Retention of phosphorus by iron and aluminum-oxides-coated quartz particles

The capacity of adsorption of P on Fe and Al-oxides-coated quartz sand has been studied. The adsorption process has been described as Freundlich and Langmuir isotherms. In all cases Langmuir equation yields better fits than Freundlich equation. The covering quartz particles with Fe and Al oxides provide a high capacity adsorption and immobilization of P from natural and waste waters. The values obtained for adsorption, desorption and adsorption/desorption cycles show that Al oxides particles provide an excellent material for construction of a P removal system for waste waters. The characteristics of this material would allow the design of a complementary filtration system to reduce P levels in the effluent, reducing contamination risks and combating eutrophication of nearby watercourses.

Expression of proinflammatory cytokines by hepatic macrophages in acute classical swine fever

Fourteen pigs were inoculated with the 'Alfort 187' strain of classical swine fever (CSF) virus and killed in pairs at 2, 4, 7, 9, 11, 14 or 17 days post-inoculation for histopathological, ultrastructural and immunohistochemical examination. For the latter method, the antibodies used were those against viral antigen Gp55, porcine myeloid marker SWC3, IL-1alpha, IL-6, TNF-alpha and Factor VIII-related antigen. Activation and increase in the number of hepatic macrophages was observed following viral detection in liver, as well as an increase in IL-1alpha and IL-6 production, mainly by Kupffer cells. Maximum detection of viral antigen was observed in the middle stage of the experiment coinciding with overexpression of the three cytokines studied, with IL-6 production by interstitial macrophages prominent at the end. Additionally, the labelling of platelets for Factor VIII-related antigen and the ultrastructural study of the sinusoids revealed activation and aggregation of thrombocytes close to Kupffer cells at the beginning of the infection. The liver seems to play a prominent role in the origin of the thrombocytopenia that occurs in CSF and contributes to the overexpression of proinflammatory cytokines considered responsible for the disorders observed during the course of the disease.

[Anuran fauna from Salta city, Argentina]

The loss and transformation of habitat by anthropogenic activities is one of the main causes of biodiversity decrease. Amphibians are declining all over the world and one of the causes of this decline is thought to be habitat reduction. However, there are anuran populations in highly disturbed habitats, like cities. This study presents the ecological baseline needed to understand anuran communities in urban environments, for Salta City. Argentina (ca. 502,000 inhabitants). The sample was stratified by environments defined by infrastructure and geographic location. The species were identified by visual encounter techniques and by auditory transect during the 2002-2003 reproductive period. Three families, seven genera and twelve species were recorded and the species richness decreased from city border to center. Similarity index values among geographic areas was higher East-West (94.7) than South-West (33.3). Bufo arenarum was the only species recorded in all environments. Hyla andina and Odontophrynus americanus had a restricted distribution and are here considered vulnerable. The border effect can explain some distribution pattern in these populations. A map of the potential distribution of recorded species for Salta is provided.

Evolution of T Lymphocytes and Cytokine Expression in Classical Swine Fever (CSF) Virus Infection

This study characterized the cell-mediated immune response in pigs inoculated with the Alfort 187 isolate of classical swine fever (CSF) virus. Quantitative changes in the T-lymphocyte population (CD3(+), CD4(+) and CD8(+)) and qualitative changes in cytokine expression (IL-2, IL-4 and IFNgamma) by these cells in serum, thymus and spleen were demonstrated. These changes coincided spatially and temporally with previously described quantitative and qualitative changes in monocyte-macrophage populations, thus demonstrating the contribution of the two cell populations to lymphoid depletion. Moreover, examination of cytokine expression in thymus and spleen samples revealed a type 1 cell-mediated immune response in the early and middle stages of the experiment, giving way to a type 2 immune response towards the end of the experiment; these findings, which accorded with the serological results and lymphopenia, may influence the delayed humoral response characteristic of CSF.

Proinflammatory Cytokines Induce Lymphocyte Apoptosis in Acute African Swine Fever Infection

Twenty-one pigs inoculated with a highly virulent isolate (E70) of African swine fever (ASF) virus were killed 1-7 days later; a further three animals served as uninfected controls. An early increase in TNF-alpha, IL-1alpha, IL-1beta and IL-6 expression was detected in lymphoid organs from infected animals, together with an increase in the serum concentrations of TNF-alpha and IL-1beta. These changes were accompanied by increased apoptosis of lymphocytes, and the presence of infected and uninfected macrophages showing changes indicative of secretory and phagocytic activation. The present study demonstrated an increase in the number of macrophages expressing TNF-alpha, IL-1 and IL-6 in proximity to lymphocytes undergoing apoptosis, supporting previous suggestions that in acute ASF proinflammatory cytokines induce lymphocyte apoptosis.

Bioelectrical impedance vector analysis in haemodialysis patients: relation between oedema and mortality

In this work, bioelectrical impedance vector analysis (BIVA) method is used in a sample of haemodialysis patients in stable (without oedema) and critical (hyperhydrated and malnutrition) states, in order to establish the relation between hyperhydration (oedema) and mortality. The measurements obtained were single frequency (50 kHz), tetrapolar (hand-foot) complex impedance measurements (vector components are: resistance R and reactance Xc). The impedance components were standardized by the height H of the subjects, (R/H and Xc/H) to obtain de impedance vector Z/H, that is represented in the RXc plot (abscise R/H, ordinate Xc/H). Measurements were performed on a sample of 74 patients (30 men and 44 women, 18-70 year, body mass index (BMI), 19-30 kg m(-2)) at the Saturnino Lora University Hospital in Santiago de Cuba. The 46 stable patients comprised 28 men and 18 women; the 28 critical patients 16 men and 12 women. The reference population consisted of 1196 healthy adult subjects living in Santiago de Cuba (689 men and 507 women, 18-70 year, BMI 19-30 kg m(-2)). We used the RXc plot with the BIVA method to characterize the reference population using the 50%, 75% and 95% tolerance ellipses. Student's t-test and Hotelling's T2-test were used to analyse the separation of groups obtained by means of clinical diagnosis and those obtained by BIVA. We obtained a significant difference (P < 0.05) in R/H, Xc/H and phase angle (PA) in men as in women between the location of Z/H vectors in the RXc graph and the separation made by the doctors between stable and critical patients. Critical (hyperhydrated) patients were located below the inferior pole of the 75% tolerance ellipse, whereas stable patients were within the tolerance ellipses. Some cases classified as stable by the clinic were classified as hyperhydrated by BIVA with 100% sensitivity and 48% specificity. In conclusion, the BIVA method could be used to classify patients by hydration state and to predict survival. Advantages of the method are its simplicity, objectivity and that it does not require the definition of patient dry weight.

Immunohistochemical Detection of the Expression of Pro-inflammatory Cytokines by Ovine Pulmonary Macrophages

The aim of this study was to determine the expression of three proinflammatory cytokines by pulmonary macrophages of sheep in paraffin wax-embedded tissue. Samples of lung from seven healthy sheep were fixed by immersion in either 10% neutral buffered formalin, acetic formalin, paraformaldehyde-lysine-periodate or Bouin's solution and processed for structural and immunohistochemical studies. The expression of interleukin (IL)-1alpha, IL-6 and tumour necrosis factor (TNF)-alpha by pulmonary intravascular macrophages (PIMs) and alveolar macrophages (AMs) was detected by the avidin-biotin-peroxidase (ABC) technique. Bouin's solution proved to be the most suitable fixative and Tween 20 the most effective pretreatment for increasing permeability. Constitutive expression of IL-1alpha, IL-6 and TNF-alpha by both macrophage populations was detected. The number of PIMs expressing IL-1alpha (the predominant cytokine in ovine lung) was higher than that of AMs, while the expression of IL-6 was greater in AMs. No differences between PIMS and AMs were found in respect of TNF-alpha expression. The evaluation of cytokine expression represents a valuable tool for studying the pathogenesis of disease in the ovine lung.

Apoptosis of thymocytes in experimental African Swine Fever virus infection

This paper report on the lesions occurred in the thymus in experimental acute African swine fever (ASF). Twenty-one pigs were inoculated with the highly virulent ASF virus (ASFV) isolate Spain-70. Animals were slaughtered from 1 to 7 days post infection (dpi). Three animals with similar features were used as controls. Thymus samples were fixed in 10% buffered formalin solution for histological and immunohistochemical study and in 2.5% glutaraldehyde for ultrastructural examination. For immunohistochemical study, the avidin-biotin-peroxidase complex (ABC) technique was used to demonstrate viral protein 73 and porcine myeloid-histiocyte antigen SWC3 using specific monoclonal antibodies. Cell apoptosis was evaluated by the TUNEL assay. Blood samples were taken daily from all pigs and were used for leukocyte counts. The results of this study show a severe thymocyte apoptosis not related to the direct action of ASFV on these cells, but probably to a quantitative increase in macrophages in the thymus and their activation. A decrease in the percentage of blood lymphocytes was observed at the same time No significant vascular changes were observed in the study. With these results we suggest that ASFV infection of the thymus does not seem to play a critical role in the acute disease. Although severe apoptosis was observed, animals died because of the severe lesions found in the other organs.

[Post-transplant diabetes mellitus associated with acute hepatitis C virus infection in a renal transplant recipient]

There are some controversial reports about the pathogenic role of hepatitis C virus infection on diabetes mellitus in renal graft recipients. We report a case of a renal transplanted who developed diabetes mellitus post-transplantation during an acute hepatitis C virus infection. We discuss the multifactorial etiology of post-transplant diabetes mellitus, and the possible interaction between tacrolimus and an acute virus C infection on its pathogenesis.

Ras-GRF1 signaling is required for normal beta-cell development and glucose homeostasis

Development of diabetes generally reflects an inadequate mass of insulin-producing beta-cells. beta-cell proliferation and differentiation are regulated by a variety of growth factors and hormones, including insulin-like growth factor I (IGF-I). GRF1 is a Ras-guanine nucleotide exchange factor known previously for its restricted expression in brain and its role in learning and memory. Here we demonstrate that GRF1 is also expressed in pancreatic islets. Interestingly, our GRF1-deficient mice exhibit reduced body weight, hypoinsulinemia and glucose intolerance owing to a reduction of beta-cells. Whereas insulin resistance is not detected in peripheral tissues, GRF1 knockout mice are leaner due to increased lipid catabolism. The reduction in circulating insulin does not reflect defective glucose sensing or insulin production but results from impaired beta-cell proliferation and reduced neogenesis. IGF-I treatment of isolated islets from GRF1 knockouts fails to activate critical downstream signals such as Akt and Erk. The observed phenotype is similar to manifestations of preclinical type 2 diabetes. Thus, our observations demonstrate a novel and specific role for Ras-GRF1 pathways in the development and maintenance of normal beta-cell number and function.

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.

African swine fever and classical swine fever: a review of the pathogenesis

This paper describes major pathogenetic mechanisms of African and Classical Swine Fever virus infections. The interactions between both viruses and the monocyte-macrophage-system result in the release of mediator molecules, which are important for the further progression of the diseases. The causes of the thrombocytopenia and the mechanisms of the haemorrhages, which are characteristic in both infections, are described. Apoptotic cell death is regarded as the predominant cause of lymphopenia in both virus infections.

Firing activity and postsynaptic properties of morphologically identified neurons of ventral oral pontine reticular nucleus

The ventral part of the oral pontine reticular nucleus (vRPO) is an important region for the generation and maintenance of REM sleep. Firing activity and synaptic response properties of morphologically identified vRPO neurons have been investigated in urethane-anaesthetized cats. Extracellular recordings were performed through recording micropipettes and neurons were extracellularly stained with biocytin. Two types of neurons were identified under spontaneous conditions: type I neurons (77%) are characterized by non-rhythmic firing; type II neurons (23%) display single spikes firing rhythmically at between 7 and 22 Hz. Type I neurons displayed ellipsoid somata with thick dendritic trunks and axons that arose from either the soma or the initial dendritic segment; these axons could not be clearly followed. Type II neurons showed polygonal somata with radial dendrites; their axons branched at a small distance from the soma. Electrical stimulation of the contralateral vRPO elicited responses in both neuron types (57% and 31%, respectively); this effect was blocked by the non-NMDA glutamatergic receptor antagonist CNQX. Electrical stimulation of the PpT evoked orthodromic responses in type I neurons (41%) and inhibited the firing rate of all type II neurons for 50-100 ms. Both effects were blocked by the muscarinic receptor antagonist atropine. The cholinergic agonist, carbachol, increased the firing rate in most type I neurons and inhibited most type II neurons in these animals. The results demonstrated that the activity of vRPO neurons is modulated through the postsynaptic activation exerted by extrinsic afferents on cholinergic and glutamatergic receptors.

Immune complex-associated thrombocytopenic purpura syndrome in sexually mature Göttingen minipigs

Eleven cases of thrombocytopenic purpura (TP) in sexually mature male or female Göttingen minipigs occurred sporadically over 3 1/2 years in a closed breeding colony protected by strict barrier conditions. Typical clinical signs of TP, including extensive subcutaneous haemorrhages, were seen in all affected animals. Haematological abnormalities included marked thrombocytopenia and anaemia. A consistent histopathological finding was the presence of membranoproliferative lesions in the renal glomeruli. Immunohistochemically, glomerular deposits were positively labelled for complement factor C1q and often also for immunoglobulins. Bone marrow findings consisting of increased numbers of immature and apoptotic megakaryocytes were compatible with a state of increased platelet consumption. Based on the combined presence of thrombocytopenia and renal immune complexes, it is suggested that the syndrome was related to a type III hypersensitivity reaction. However, further studies are needed to verify this hypothesis.

Apoptosis of thymocytes related to cytokine expression in experimental classical swine fever

Atrophy of the thymic cortex and loss of thymocytes were studied in 32 pigs inoculated with the virulent strain "Alfort" of classical swine fever (CSF) virus and killed at intervals from 2 to 15 days after infection. Immunohistochemical, ultrastructural, ELISA and TUNEL methods were used. The results suggested that direct action of CSF virus on thymocytes played no more than a minor role. The massive lymphoid depletion observed in the thymus, may, however, have been associated with the numerical increase in monocytes-macrophages in this organ, and their secretory activation, leading to synthesis and release of tumour necrosis factor (TNF)-alpha, interleukin (IL)-1alpha and C1q complement component as main chemical mediators, and IL-1beta and IL-6 as minor mediators. These cytokines (TNF-alpha and IL-1alpha) may have played a role in the apoptosis of thymocytes, demonstrated by TUNEL and ultrastructural methods. The pathogenetic mechanism outlined may contribute to the lymphoid depletion observed in others organs in CSF and may explain the lymphopenia characteristic of the disease.

Viscosity minimum in bimodal concentrated suspensions under shear

We study a model of concentrated suspensions under shear in two dimensions. Interactions between suspended particles are dominated by direct-contact viscoelastic forces and the particles are neutrally bouyant. The bimodal suspensions consist of a variable proportion between large and small droplets, with a fixed global suspended fraction. Going beyond the assumptions of the classical theory of Farris (R.J. Farris, Trans. Soc. Rheol. 12, 281 (1968)), we discuss a shear viscosity minimum, as a function of the small-to-large-particle ratio, in shear geometries imposed by external body forces and boundaries. Within a linear-response scheme, we find the dependence of the viscosity minimum on the imposed shear and the microscopic drop friction parameters. We also discuss the viscosity minimum under dynamically imposed shear applied by boundaries. We find a reduction of macroscopic viscosity with the increase of the microscopic friction parameters that is understood using a simple two-drop model. Our simulation results are qualitatively consistent with recent experiments in concentrated bimodal emulsions with a highly viscous or rigid suspended component.

Histopathological and ultrastructural changes associated with herpesvirus infection in waterfowl

Duck virus enteritis is an acute contagious viral disease affecting birds of the order Anseriformes (ducks, geese and swans). The disease agent is a member of the Herpesviridae family (Anatidae herpes virus 1). A group of Anseriformes waterfowl from a Nature Reserve and Centre for the Recovery of Endangered Species in Spain suffered an outbreak of the disease, affecting adults, young and newborns. Other non-Anseriformes waterfowl such as coots, from the family Rallidae, order Gruiformes, were also affected. Histopathological and ultrastructural findings confirmed the viral infection. The present study provides evidence that birds different from the order Anseriformes can be affected, suggesting that the virus has the ability to infest other non-Anseriformes waterfows.

Targeted disruption of Ras-Grf2 shows its dispensability for mouse growth and development

The mammalian Grf1 and Grf2 proteins are Ras guanine nucleotide exchange factors (GEFs) sharing a high degree of structural homology, as well as an elevated expression level in central nervous system tissues. Such similarities raise questions concerning the specificity and/or redundancy at the functional level between the two Grf proteins. grf1-null mutant mice have been recently described which showed phenotypic growth reduction and long-term memory loss. To gain insight into the in vivo function of Grf2, we disrupted its catalytic CDC25-H domain by means of gene targeting. Breeding among grf2(+/-) animals gave rise to viable grf2(-/-) adult animals with a normal Mendelian pattern, suggesting that Grf2 is not essential for embryonic and adult mouse development. In contrast to Grf1-null mice, analysis of grf2(-/-) litters showed similar size and weight as their heterozygous or wild-type grf2 counterparts. Furthermore, adult grf2(-/-) animals reached sexual maturity at the same age as their wild-type littermates and showed similar fertility levels. No specific pathology was observed in adult Grf2-null animals, and histopathological studies showed no observable differences between null mutant and wild-type Grf2 mice. These results indicate that grf2 is dispensable for mouse growth, development, and fertility. Furthermore, analysis of double grf1/grf2 null animals did not show any observable phenotypic difference with single grf1(-/-) animals, further indicating a lack of functional overlapping between the two otherwise highly homologous Grf1 and Grf2 proteins.

African swine fever: Expression of interleukin-1 alpha and tumour necrosis factor-alpha by pulmonary intravascular macrophages

To determine, in the acute form of African swine fever (ASF), the relationship between the appearance of pulmonary oedema and viral replication and expression of cytokines by pulmonary intravascular macrophages (PIMs), 14 pigs were inoculated intramuscularly with ASF virus (strain España'70) and killed in pairs on days 1-7 post-inoculation. Samples of lung were examined immunohistochemically and ultrastructurally. The immunohistochemical study was carried out with antibodies against interleukin-1 alpha (IL-1alpha), tumour necrosis factor-alpha (TNF-alpha), viral antigen of ASF (Vp73) and a myeloid marker (SWC3). Viral replication was observed mainly in PIMs, which at the same time showed intense activation, accompanied by the expression of IL-1alpha and TNF-alpha. The occurrence of interstitial oedema, neutrophil sequestration and fibrin microthrombi in septal capillaries coincided with high degrees of cytokine expression by infected PIMs. Alveolar macrophages did not show a significant change in cytokine expression as a result of ASF infection, and viral replication was detected in only a low percentage of these cells.

Asymptomatic brugada syndrome case unmasked during dimenhydrinate infusion

Typical ECG of that described for Brugada syndrome was elicited in a patient diagnosed with labyrinthopathy during infusion of dimenhydrinate, a first-generation antihistamine usually used to treat motion sickness. Although the patient had no history of syncope or palpitations, and there was no family history of cardiac disease or sudden death, the ECG abnormality was reproduced later with intravenous flecainide, and an asymptomatic Brugada syndrome was diagnosed.

Angiotensin II AT(1) receptor antagonists and platelet activation

Multiple factors are involved in thrombus formation and require complex and highly therapeutic strategies. Platelet activation plays a critical role in the genesis of acute coronary syndromes involving not only platelets but also endothelial cells, leucocytes and erythrocytes. Angiotensin II (Ang II) is a vasoconstrictor that could participate in the thrombotic process. Platelets also express Ang II AT1 type receptors on their surface. Losartan is a non-peptidic inhibitor of AT1 receptors. It has been demonstrated that losartan reduced platelet aggregation induced by the thromboxane A2 (TXA2) analogue U46619. This effect was not observed with the losartan metabolite EXP 3174. The effect of losartan was assessed in binding studies in which losartan competitively inhibited the binding of [3H]U46619 to platelets in a dose-dependent manner. Irbesartan also inhibits the TXA2 receptor in platelets, an effect that was not obtained with the active form of candesartan, CV11974, and with valsartan. These results suggest that the structural requirements necessary to antagonize the TXA2/PGH2 platelet receptor may be different from those involved in AT1 receptor antagonism. The in vivo relevance of the in vitro findings has been confirmed by the fact that in vivo administration of losartan decreases P-selectin expression in platelets obtained from stroke-prone spontaneously hypertensive rats.

Elastofibroma dorsi as a cause of shoulder pain or snapping scapula

Elastofibroma dorsi is a benign soft tissue tumor, not well-known because of its low incidence, located in the chest wall in the subscapular area. In 10 patients with elastofibroma dorsi, the clinical symptoms were snapping scapula or shoulder pain. In three of the patients, the previous diagnosis was shoulder impingement, and the patients were treated without success. The clinical diagnosis was confirmed by magnetic resonance imaging. Surgical treatment resolved the symptoms in all patients. This tumor should be considered in the differential diagnosis of snapping scapula or shoulder impingement.

[Doxazosin and soluble guanylate cyclase in a rat model of hypertension]

BACKGROUND

Although different studies have evaluated the ability of endothelial cells to produce NO in the setting of the endothelial dysfunction associated with hypertension, less it is known about the soluble guanylate cyclase system.

AIM

To analyze the level of expression of sGC in the vascular wall in Stroke-prone spontaneously hypertensive rats (SHRSP). Moreover, the effect of treatment with an alpha1 adrenergic antagonist, doxazosin, on sGC expression was also evaluated.

METHODS

The study was performed in 24 untreated 20-week-old SPSHR and 12 SPSHR treated orally with doxazosin (10 mg/Kg bw/day; for 15 days). A group of normotensive Wistar-Kyoto (WKY) rats were used as controls (n = 12).

RESULTS

Isolated aortic segments from SHRSP showed impaired response to SNP. Doxazosin treatment prevented impaired vasodilatory response to SNP. Expression of the beta1 sGC in the vascular wall of SHRSP determined by Western blot and immunohistochemistry was markedly reduced with respect to that of WKY. Doxazosin treatment increased of beta1 sGC expression in treated SHRSP particularly at the medium level with respect to that of untreated SHRSP.

CONCLUSION

SHRSP showed reduced expression of beta1 sGC in the vascular wall and an impaired vasodilator response to SNP which improved with doxazosin treatment. These results suggest the role the sGC system may play in the global treatment of endothelial dysfunction.

Inhibition of platelet activation in stroke-prone spontaneously hypertensive rats: comparison of losartan, candesartan, and valsartan

In vitro studies have suggested that losartan interacts with the thromboxane (TxA2)/ prostaglandin H2 (PGH2) receptor in human platelets, reducing TxA2-dependent platelet activation. The aim of this study was to evaluate the effect of different angiotensin II type 1 receptor antagonists in stroke-prone spontaneously hypertensive rats (SHRSP). The level of platelet activation was assessed by determining P-selectin expression in platelets by flow cytometry. The ex vivo adhesion of platelets was also analyzed. The number of platelets that expressed P-selectin in SPSHR was significantly increased (% P-selectin expression: WKY 4 +/- 0, 4%; SHRSP 15.5 +/- 0, 8% [n = 8], p < 0.05). In SHRSP receiving losartan (20 mg/kg body weight per day) the percentage of platelets expressing P-selectin fell to levels close to that observed in WKY. The number of platelets from SHRSP treated with valsartan and candesartan (20 mg/kg body weight per day for 14 days) that expressed P-selectin was not significantly different from those from untreated SPRHR. Only losartan treatment reduced ex vivo platelet adhesion to a synthetic surface. The antiplatelet effect of losartan does not appear to be related to the level of blood pressure reduction. In ex vivo experiments, losartan significantly reduced the binding of the radiolabeled TxA2 agonist U46619 to platelets obtained from SHRSP in a dose-dependent manner. Treatment with losartan reduced the number of activated platelets in SHRSP independently of its blood pressure effects. TxA2-receptor blockade is proposed as a mechanism by which losartan can prevent platelet activation.