R. Cruz

β-Ag2MoO4 microcrystals: Characterization, antibacterial properties and modulation analysis of antibiotic activity

This study reports the antibacterial properties and modulation analysis of antibiotic activity by β-Ag2MoO4 microcrystals as well as their structural and vibrational characterization. The silver molybdate was obtained by the conventional hydrothermal method, and the structural, vibrational and morphological properties of the sample were determined using X-ray diffraction, Raman spectroscopy and scanning electron microscopy images. β-Ag2MoO4 microcrystals obtained show spinel-type cubic structure (Fd-3m) with irregular shapes. The evaluation of antibacterial and modulatory-antibiotic activity was performed using the microdilution method to determine the Minimum Inhibitory Concentration (MIC) of the β-Ag2MoO4 and antibiotics alone and associated with the silver molybdate. The β-Ag2MoO4 modulates the antibiotic activity against all bacteria assayed in a synergistic (as the norfloxacin and gentamicin against S. aureus and gentamicin against E. coli) or an antagonistic form (as the norfloxacin against E.coli and P. aeruginosa). The reversion of antibiotic resistance by combinations with Ag2MoO4 could be a novel strategy to combat infections caused by multiple drug resistance (MDR) pathogens. Our results indicate that these silver molybdates present a clinically relevant antibacterial activity and enhanced the antibiotic activity of some antibiotics against MDR strain of S. aureus and E. coli, being an interesting alternative to combat antibiotic-resistant bacterial infectious agents.

Evaluation of renal injury caused by acute volume replacement with hydroxyethyl starch 130/0.4 or Ringer's lactate solution in pigs

This work aimed to evaluate the effects on renal tissue integrity after hydroxyethyl starch (HES) 130/0.4 and Ringers lactate (RL) administration in pigs under general anesthesia after acute bleeding. A total of 30 mL/kg of blood were passively removed from the femoral artery in two groups of Large White pigs, under total intravenous anesthesia with propofol and remifentanil. After bleeding, Group 1 (n = 11) received RL solution (25 mL/kg) and Group 2 (n = 11) received HES 130/0.4 solution (20 mL/kg). Additionally, Group 3 (n = 6) was not submitted to bleeding or volume replacement. Pigs were euthanized and kidneys were processed for histopathological and immunohistochemical analyses. Minimal to moderate glomerular, tubular, and interstitial changes, as well as papillary necrosis, were observed in all experimental groups. Pre-apoptosis and apoptosis indicators were higher in pigs that received HES 130/0.4, indicating a higher renal insult. Both HES 130/0.4 and RL administration may cause renal injury, although renal injury may be more significant in pigs receiving HES 13/0.4. Results also suggest that total intravenous anesthesia with propofol and remifentanil may cause renal injury, and this effect can be dose related.

Modulation of antibiotic effect by Fe2(MoO4)3 microstrutures

ABSTRACT In this study, we report the antibacterial activity and modulation of antibiotic activity by Fe2(MoO4)3 microstructures obtained by the hydrothermal route without use of surfactants or organic additives. This material was characterized by X‐ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM) images. The XRD pattern showed that the Fe2(MoO4)3 crystallize in a monoclinic structure without secondary phases. Raman spectroscopy confirms the formation of Fe2(MoO4)3. SEM images show that the Fe2(MoO4)3 obtained have ball‐of‐yarn shaped morphology. In the antibacterial assays, strains of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus were assayed by microdilution method to evaluate the antibacterial and modulatory‐antibiotic activity with antibiotics as gentamicin, norfloxacin and imipenem. Against all bacteria, the Minimum Inhibitory Concentration (MIC) was Fe2(MoO4)3 ≥ 1024 &mgr;g/mL. This high MIC result must be associated with the fact of the iron be an essential microelement to the bacterial growth. However, when the Fe2(MoO4)3 was assayed in association with the antibiotics was observed an antagonistic effect demonstrated by an enhance of the MIC. This fact is associated directly with the pro‐oxidative properties of metallic oxides. These compounds enhance the production of free radicals, as H2O2 and superoxide ions that can affect the cell structures as cell membrane and cell wall. Other effect is associated with the possible coordination of the metal, performing bonds with the chemical structure of the antibiotics, reducing their activity. Our results indicated that nanocompounds as Fe2(MoO4)3 can not be used as antimicrobial products for clinical usage, neither directly and neither in association with antibiotics. Graphical abstract Figure. No Caption available.

Prospective Serosurvey of Coxiella burnetii Antibodies in Selected Sheep of Portugal

Q fever is a zoonotic disease caused by Coxiella burnetii that is highly prevalent across the world. In this study, a prospective serosurvey was performed to study C. burnetii circulation in a population of sheep in the central region of Portugal. Blood from a representative sample of 168 animals was drawn in both 2015 and 2016, and sera were tested for IgG anti-C. burnetii by EIA. In 2015, 7.7% (13/168) animals tested positive for IgG anti-C. burnetii, while in 2016, 17.3% (29/168) tested positive, showing a statistically significant (P = 0.008) increase in anti-C. burnetii seroprevalence. Results support the notion that Q fever is emerging in central Portugal.

Epidemiology and Emergence of Schmallenberg Virus Part 1: Origin, Transmission and Differential Diagnosis

Schmallenberg virus (SBV) is a novel Orthobunyavirus causing mild clinical signs in cows and malformations in aborted and neonatal ruminants in Europe. SBV belongs to the family Bunyaviridae and is transmitted by biting midges. This new virus was identified for the first time in the blood samples of cows in the city of Schmallenberg in North‐ Rhine‐Westphalia in November 2011. Since then the virus spread to several European countries. Here we describe the origin and emergence, as well as the transmission and the differential diagnosis of this virus, now known to be a serious threat to Veterinary Public Health.

Epidemiology and Emergence of Schmallenberg Virus Part 2: Pathogenesis and Risk of Viral Spread

Schmallenberg virus (SBV) is a novel Orthobunyavirus causing mild clinical signs in cows and malformations in aborted and neonatal ruminants in Europe. SBV belongs to the family Bunyaviridae and is transmitted by biting midges. This new virus was identified for the first time in blood samples of cows in the city of Schmallenberg in North-Rhine Westphalia in November 2011. Since then, the virus spread to several European countries. Here, we describe the pathogenesis and the risk of viral spread in the Portuguese territory.

Renal Apoptosis Signalling in a Pig Haemorrhagic Model after Volume Replacement with HES 130/0.4 or Ringer's Solution

RENAL APOPTOSIS SIGNALLING IN A PIG HAEMORRHAGIC MODEL AFTER VOLUME REPLACEMENT WITH HES 130/0.4 OR RINGER’S SOLUTION R. Cruz*,y,z, H. Vala*,y, A. Machado*,y, C. Venâncio z, J.R. Mesquita*,y, A. Silva x, A.L. Ortiz{ and D. Ferreira *ESAV, IPV, yCI&DETS, IPV, zUTAD, xREQUIMTE, Portugal, {Le on University, Spain and CICV/FMV-ULHT, Portugal Introduction: TUNEL labelling is one of the most frequently used methods to detect apoptosis in renal tissues. The aim of this study was to evaluate kidney damage after acute haemorrhage and volume replacement with a colloid or a crystalloid, in a pig model. Materials and Methods: In accord with animal welfare regulations, three groups (n 5 6) of large white pigs were enrolled in the study. All groups underwent total intravenous anaesthesia and were subjected to acute haemorrhage and volume replacement with Ringer’s lactate or HES 130/0.4, 20 min after haemorrhage. Control pigs did not undergo bleeding and volume replacement. Pigs were killed and renal samples were taken and analyzed by the TUNEL method. ANOVA was used to compare data between groups. Results: An intense positive signal in tubular epithelial cells was observed in all samples. The level of signalling per mm was significantly lower in the group receiving Ringer’s lactate (11.94) compared with the group receiving HES130/0.4 (67.94) and controls (146.34) (P !0.05). Conclusions: Signalling levels were lower in pigs subjected to fluid replacement with Ringer’s lactate when compared with the control group. Ringer’s lactate might promote better renal perfusion in the presence of severe hypoperfusion. HISTOLOGICAL EVALUATION OF THE SPLEEN AFTER ACUTE BLEEDING FOLLOWED BY VOLUME REPLACEMENT WITH TWO DIFFERENT PHYSIOLOGICAL SOLUTIONS M. Cabral*, A. Ortiz y, C. Venâncio z, J. Mesquita x, C. N obrega x, A. Silva{, H. Vala x and D. Ferreira *Agrarian Superior School, IPV Viseu, Portugal, yUniversity of Le on, Spain, zIBMC-Porto, xCEETS-IPV Viseu, {REQUIMTE, Porto and CICVULHT, Lisboa, Portugal Introduction: The spleen is important for many haemopoietic and immunological functions, particularly in haemodynamic compensation during haemorrhagic shock, with a crucial role in restoring blood volume in situations of acute haemorrhage. The administration of physiological solutions is of great importance for the correction of circulating volume, avoiding complications due to hypovolaemia. The aim of this study was to evaluate histopathological changes in the spleen associated with volume replacement using two different physiological solutions (hydroxyethyl starch [HES] 130/0.4 and Ringer’s lactate), after acute controlled bleeding, in a pig model. Materials andMethods: Thirty-one large white pigs underwent total intravenous anaesthesia with propofol and remifentanil. A total of 25ml/kg of blood was removed passively over 20 min. Intravascular volume was replaced using Ringer’s lactate at 25 ml/kg (group 1, n 5 13) or HES130/0.4 at 20 ml/kg (group 2, n 5 11). Spleen samples were processed for routine histopathological evaluation. Results: Significant differences were found in lymphoid follicular hyperplasia between the control group and group 1, and between group 1 and group 2, with increased follicular hyperplasia in group 1. Conclusions: Volume replacement with HES130/0.4 may reduce follicular lymphoid hyperplasia when compared with volume replacement with Ringer’s lactate after acute bleeding.

The Endocrine Glands in the Dog: From the Cell to Hormone

The animal body represents one of the more complex and perfect systems of nature. Despite its complexity and its functionality, which is incredibly effective, the control of its basic functions is performed by only two systems: the nervous system and endocrine system. The nervous system is associated with electrical and chemical signals that are transmitted at high speed, resulting in rapid organic activities. The endocrine system acts through the synthesis and release of chemical messengers and is responsible for several functions of the organism, in a slower, but more durable way.