Níveis de sódio e potássio séricos de caprinos confinados e em pastoreio

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The influence of internal surface treatments on tensile bond strength for two ceramic systems

Statement of the Problem: the ceramic composition and surface microstructure of all-ceramic restorations are important components of an effective bonding substrate. Hydrofluoric acid and sandblasting are well-known procedures for surface treatment; however, surface treatment for high alumina-containing and lithium disilicate ceramics have not been fully investigated.Purpose: This in vitro study evaluated the tensile bond strength of resin cement to two types of ceramic systems with different surface treatments.Methods and Materials: Thirty specimens of each ceramic system were made according to the manufacturer's instructions and embedded in polyester resin. Specimens of In-Ceram Alumina [1] and IPS Empress 2 [E] were distributed to three groups with differing surface treatments (n=10): sandblasting with 50 jam aluminum oxide (APA); sandblasting with 110 pm aluminum oxide modified with silica particles (ROCATEC System-RS); a combination of sandblasting with APA and 10% hydrofluoric acid etching (HA) for two minutes on In-Ceram and for 20 seconds for IPS Empress 2. After the respective surface treatments, all the specimens were silanated, and Rely-X resin cement was injected onto the ceramic surface and light polymerized. The specimens were stored in distilled water at 37 degrees C for 24 hours and thermally cycled 1,100 times (5 degrees C/55 degrees C). The tensile bond strength test was performed in a universal testing machine at a 0.5 mm/minute crosshead speed.Results: the mean bond strength values (AWa) for IPS Empress 2 were 12.01 +/- 5.93 (EAPA), 10.34 +/- 1.77 (ERS) and 14.49 +/- 3.04 (EHA). The mean bond strength values for In-Ceram Alumina were 9.87 +/- 2.40 JAPA) and 20.40 +/- 6.27 (IRS). All In-Ceram specimens treated with 10% hydrofluoric acid failed during thermal cycling.Conclusion: the Rocatec system was the most effective surface treatment for In-Ceram Alumina ceramics; whereas, the combination of aluminum oxide sandblasting and hydrofluoric acid etching for 20 seconds worked more effectively for Empress 2 ceramics.

Influence of sugar cane burning on aerosol soluble ion composition in Southeastern Brazil

Seasonal variability in the major soluble ion composition of atmospheric particulate matter in the principal sugar cane growing region of central São Paulo State indicates that pre-harvest burning of sugar cane plants is an important influence on the regional scale aerosol chemistry. Samples of particulate matter were collected between April 1999 and February 2001 in coarse (> 3.5 mum) and fine (< 3.5 mum) fractions, and analysed for HCOO-, CH3COO-, C2C42-, SO42- . Results indicated that the principal sources of the aerosols investigated NO3-, Cl-, Na+, K+, NH4+, Mg2+ and Ca2+ were local or regional in nature (scale of tens to a few hundreds of km), and that differences between air masses of varying origins were small. Fine particles were typically acidic, containing secondary nitrates, sulphates and organic species. Coarse fraction concentrations were mainly influenced by physical parameters (wind speed, movement of vehicles and surface condition) affecting rates of re-suspension, although secondary nitrate and sulphate were also present in the larger particles.Concentrations of all measured species except sodium and chloride were higher during the burning season. Although concentrations were lower than often found in polluted urban environments, the massive increases during much of the year, due to a single anthropogenic activity (sugar cane burning) are indicative of a very large perturbation of the lower troposphere in the region relative to the natural condition. These aerosols are suspected of promoting respiratory disease. They also represent an important mechanism for the tropospheric transport of species relevant to surface acidification (sulphates, nitrates, ammonium and organic acids) and soil nutrient status (potassium, nitrogen, ammonium, calcium), so their impact on fragile natural ecosystems (following deposition) needs to be considered. (C) 2004 Elsevier Ltd. All rights reserved.

Parâmetros bioquímicos sanguíneos, balanço de nitrogênio e metabolizabilidade da energia bruta em suínos alimentados com dietas contendo diferentes balanços eletrolíticos

The aim of this study was to evaluate different dietary electrolyte balance (DEB) on the blood biochemical parameters, nitrogen balances and crude metabolizable energy of swine in the initial phase. Sixteen barrows were used, averaging 27.95 kg of initial weight, allotted individually in metabolic cages in a randomized blocks design with four treatments (DEB of 160, 208, 257 and 305 mEq/kg) and 4 replicates. The blood biochemical parameters analyzed were chloride, potassium, sodium and urea in blood. Urine pH was also evaluated, and the parameters evaluated in nitrogen (N) balance were N intake, fecal N, N excreted in urine, absorbed N, N retention, retained N/absorbed N and total excretion of N. The gross energy digestibility and metabolizibility coefficients were determined, and the respectives values of digestible and metabolizable energy. The values of urinary pH increased (P < 0.01) linearly with increasing levels of DEB, ranging from 6.90 to 8.03. The results for chloride, potassium and nitrogen balances of variables and gross energy were similar (P > 0.05) between the evaluated DEB. A linear increase (P < 0.01) was also observed for sodium concentrations in blood serum due to the increase of DEB, with values of 2.91, 3.03, 3.27 and 3.18 g/l, respectively for the different treatments. Urea levels in blood serum increased linearly (P < 0.01), with values of 26.21, 28.64, 34.32 and 32.89 mg/dl. It was concluded that increasing the dietary electrolyte balance, from 160 to 305 mEq/kg resulted in higher concentrations of urea and sodium in blood serum, and higher pH values in the urine of swine in the initial phase.

Efeitos do fentanil, droperidol e inoval sobre função renal e eletrólitos (sódio e potássio)

The influence of Fentanyl, Droperidol and Innovar on renal function and electrolytes (sodium and potassium) were studied on 18 dogs. Fentanyl disturbs kidney function and decreases plasmatic potassium. Droperidol and Innovar do not disturb the main renal function but decrease plasmatic potassium. The results obtained point out the importance of associate employment of Fentamyl and Droperidol, since the latter seems to establish the renal disorders occasioned by Fentanyl, probably owing to its adrenergic α blocking action.

EFEITOS DA INFUSAO CONTINUA DO PROPOFOL SOBRE A FUNCAO RENAL DO CAO. ESTUDO COMPARATIVO COM O PENTOBARBITAL SODICO

Little research has been done with propofol in relation to renal function. The aim of this study was to evaluate the effects of the continuous infusion of propofol on renal function in dogs. Sixteen dogs, previously anesthetized with pentobarbital sodium (30 mg.kg-1) for surgical preparation, catheterism and monitoring, were studied. The dogs were mechanically ventilated with air and received alcuronium (0.2 mg.kg-1 in bolus and 0.06 mg.kg-1 - maintenance). The following parameters were studied: heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), aortic blood flow (A(o)BF - by electromagnetic flowmeter installed in the ascending aortic), aortic vascular resistance index (A(o)VRI), renal plasma flow (ERPF - by para-aminohipurate clearance), glomerular filtration rate (GFR - by creatinine clearance), effective renal blood flow (ERBF = ERPF/1 - hematocrit), urinary volume (UV), renal vascular resistance (RVR = MAP.80/ERBF.10-3), urinary sodium excretion (UE(Na)), fractionated sodium excretion (FE(Na)), osmolar clearance (C(osm)) and free water clearance (C(H2O)). These parameters were studied at 15 (M1), 30 (M2), 45 (M3) and 60 (M4) min after beginning pentobarbital sodium infusion (5 mg.kg-1.h-1). The dogs were allocated into two groups of eight animals each: G1 (control-pentobarbital sodium) and G2 (propofol). In G1, pentobarbital was given at the four times studied. G2 dogs received the same treatment as G1 dogs at M1 and M2; infusion of pentobarbital was substituted by propofol (3 mg.kg-1 bolus, followed by 12 mg.kg-1.h-1 continuous infusion) at M3 and M4. Profile Analysis was used to analyze the results statistically. In G1 (pentobarbital), there was a significant increase in RVR (M1 < M4) and a decrease in ERPF and ERBF (M1 > M4). In G2 (propofol) there was only a significant increase in A(o)BF (M1 < M2 = M3). In comparison among groups, these was a significant alteration of FE(Na) at M3 (pentobarbital > propofol). It was observed that the continuous infusion of propofol in dogs, at the given doses, did not alter the basic variables of renal function and hemodynamics studied. We concluded that propofol can be one of the drugs of choice to provide base anesthesia in studies of renal function in dogs.

EFEITOS DO SULFATE DE MAGNESIO NA HEMODINAMICA E FUNCAO RENAL DE CAES ANESTESIADOS CORN PENTOBARBITAL SODICO

Background and objectives - The use of magnesium sulphate for the prevention of seizures in pre-eclampsia may induce hypermagnesemia. Clinical and experimental studies are not in agreement about the effects of magnesium on the renal hemodynamics and function. We therefore studied the effects of hypermagnesemia on the renal hemodynamics and function of dogs anesthetized with pentobarbitone. Methods - Sixteen mongrel dogs were anesthetized with pentobarbitone 30 mg.kg-1 and submitted to extracellular ) and mechanical ventilation with room air. The dogs were volume expansion with Ringer's solution (0.4 ml.kg.min allocated into two groups of 8 animals, for the study of renal hemodynamics and function following the administration of 5 mg.kg-1 of pentobarbitone (Group 1 - control or of pentobarbitone associated with magnesium sulphate in the dose (Group 2). The parameters studied were: PAH of 140 mg.kg, administered in 15 minutes, followed by 80 mg.kg-1.h-1 clearance, creatinine clearance, osmolar clearance, free water clearance, renal blood flow, renal vascular resistance, filtration fraction, urinary volume, plasmatic and urinary osmolarity, urinary and fractionary excretion of sodium and potassium, measured at five moments: 15 (M1), 30 (M2), 60 (M3) and 75 (M4) minutes after the first supplementary dose of pentobarbitone and 15 minutes (M5) after the second supplementary dose in Group 1. In Group 2, the moments M3, M4, M5 were 15, 30 and 60 minutes after the priming dose of magnesium sulphate and during the maintenance dose. Results - In Group I no significant changes were observed in renal hemodynamic parameters and creatinine clearance. The extracellular volume expansion increased urinary volume and decreased urinary osmolarity as a consequence of sodium, potassium and free water clearance. The fractionary excretion of sodium was maintained. The plasmatic osmolarity increased. In Group 2, renal hemodynamic parameters and creatinine clearance were also maintained. There was an increase in renal sodium clearance, as detected by the increase in the fractionary excretion of sodium. Conclusions - Magnesium sulphate did not produce significant changes in renal hemodynamics and facilitated the renal excretion of sodium in dogs anesthetized with pentobarbitone.

Efeitos do alopurinol em rins isquemicos de caes anestesiados com pentobarbital sodico

Background and Objectives - Allopurinol is a drug which inhibits the formation of noxious renal free radicals. The aim of this study was to evaluate the protecting renal effects of allopurinol in ischemic kidneys of dogs. Methods - Sixteen dogs were anesthetized with sodium pentobarbital and submitted to extracellular volume expansion (1.4 ml.kg-1.min-1), to mechanic ventilation with air, to right nephrectomy and to left renal artery clamping. Changes which might occur in renal morphology and function after 30 min of total ischemia and posterior reperfusion were studied in Group 1 (G1), in addition to the action of allopurinol (50 mg.kg-1) on those kidneys, when administered 24 h before the experiment and 1 h before the ischemic procedure in Group 2 (G2). The following parameters: heart rate, inferior vena cava pressure, mean blood pressure, PAH clearance (PAH(c)), renal blood flow (RBF), renal vascular resistance (RVR), creatinine clearance (Cr(c)), filtration fraction, urine output, plasma and urine osmolality, osmolar clearance, free water, sodium and potassium clearance, urine and fractional sodium and potassium excretion, hematocrit, rectal temperature, and left kidney histology were evaluated in four moments: M1 control, and M2, M3, M4 obtained immediately, 15 and 30 min after unclamping of the left renal artery. In G2, M1, M2, M3 and M4 were obtained 45, 90, 105, and 120 min after the second allopurinol dose. Results - Both groups showed the highest values for PAH(c), RBF, and Cr(c), and the lowest values for RVR in M1. Animals were tachycardiac since the beginning of the experiment both in G1 and in G2. The other parameters were not changed. Left kidney histological evaluation showed alterations compatible with acute tubular necrosis in both experimental groups. Conclusions - Alterations found in renal hemodynamics were compatible with the release of vasoconstrictor substances due to renal ischemia. Allopurinol was not effective in preventing renal alterations caused by ischemia and reperfusion.

Action of anti-bothropic factor isolated from Didelphis marsupialis on renal effects of Bothrops erythromelas venom

Acute renal failure is the most common complication in the lethal cases caused by snakebites in Brazil. Among the Brazilian venom snakes, Bothrops erythromelas is responsible for the majority of accidents in Northeastern Brazil. Didelphis marsupialis serum could inhibit myonecrotic, hemorrhagic, edematogenic hyperalgesic and lethal effects of envenomation determined by ophidian bites. In the present study, we evaluated the action of the anti-bothropic factor isolated from D. marsupialis on the renal effects promoted by B. erythromelas venom without systemic interference. Isolated kidneys from Wistar rats were perfused with Krebs-Henseleit solution containing 6% bovine serum albumin. We analyzed renal perfusion pressure (PP), renal vascular resistance (RVR), glomerular filtration rate (GFR), urinary flow (UF), and the percentages of sodium and potassium tubular transport (%TNa +, %TK +). The B. erythromelas venom (10 μg mL -1) decreased the PP (ct=108.71±5.09 mmHg; BE=65.21±5.6 mmHg*) and RVR (ct=5.76±0.65 mmHg mL -1 g -1 min -1; BE=3.10±0.45 mmHg mL -1 g -1 min -1*) . On the other hand, the GFR decreased at 60 min (ct 60=0.76±0. 07 mL g -1 min -1; BE 60=0.42±0.12 mL g -1 min -1*) and increased at 120 min (ct 120=0.72±0.01 mL g -1 min -1; BE 120=1.24±0.26 mL g -1 min -1*). The UF increased significantly when compared with the control group (ct=0.14±0.01 mL g -1 min -1; BE=0.47±0.08 mL g -1 min -1*). The venom reduced the %TNa + (ct 90=79.18±0.88%; BE 90=58.35±4.86%*) and %TK + (ct 90=67.20±4.04%; BE 90=57. 32±5.26%*) The anti-bothropic factor from D. marsupialis (10 μg mL -1) incubated with B. erythromelas venom (10 μg mL -1) blocked the effects on PP, RVR, %TNa +, and %TK +, but was not able to reverse the effects in UF and GFR promoted by venom alone. However, the highest concentration of D. marsupialis serum (30 μg mL -1) reversed all the renal effects induced by the venom. In conclusion, B. erythromelas venom altered all the renal functional parameters evaluated and the anti-bothropic factor from D. marsupialis was able to inhibit the effects induced by the venom in isolated kidney. © 2005 Elsevier Ltd. All rights reserved.

Changes in blood parameters of hybrid tambacu fish parasitized by Dolops carvalhoi (Crustacea, Branchiura), a fish louse

Measurement of blood parameters has been used for many years as a tool for monitoring the health offish. The present study investigated the effects of a natural infestation of Dolops carvalhoi Lemos de Castro, 1949, on red blood cells, thrombocytes and white blood cell counts, as well as plasma glucose and serum electrolyte levels in hybrid tambacu (Piaractus mesopotamicus × Colossoma macropomum). Parasitized fish showed low haematocrit and magnesium levels and increases in MCHC, plasma glucose levels, serum protein, sodium and chloride levels, number of monocytes and PAS-positive granular leukocytes (PAS-GL), when compared with values in control fish. This study is the first to report changes in fish physiology caused by D. carvalhoi infestation, and the results obtained indicate that a mild infection can lead to important osmoregulatory disturbances in hosts.

Efeitos da ciclosporina a sobre a função renal de cães da raça Golden Retriever normais ou afetados pela distrofia muscular

The muscular dystrophy of Golden Retriever is a degenerative miopaty caused by the absence of dystrophy and it is genetically homologue of the Duchenne muscular dystrophy in humans, so, these dogs are considerably experimental models for studies on cellular therapy. Their successful depends of the adequate immunosuppression. Cyclosporin A is indicated for that and the monitoring of blood concentration and adverse effects are essential to viabilise the therapy. It was studied GRMD dogs, and normal dogs from the same breed, submitted for therapy with CsA, associated, on GRMD, of cell transplantation. It was evaluated the possible effects of the drug on renal functions. It has been considerate the clinic manifestations, urinalisis, testis of glomerular function and blood concentrations of urea, cretinine, sodium and potassium. In our results we found a discrete increase of blood urea on booth groups; increased levels of urine's cylinders and protein and also increase of urinary density on GRMD group. CsA therapy could make acute lesions on renal tubules, especially on GRMD. These dogs also have different reactions than normal dogs on relation of ions homeostasis and renal function. However, earlier diagnosis and adequate treatment could prevent the development of renal diseases.

Atividade rizosférica de solo tratado com herbicida durante processo de remediação por Stizolobium aterrimum

This study aimed to evaluate the soil microbiota activity associated to S. aterrimum rhizosphere, during the phytoremediation process of a soil contaminated with trifloxysulfuron-sodium. S. aterrimum was cultivated in vases (6, 0 L) filled with soil, after trifloxysulfuron-sodium, at 7.5 g ha -1, was applied or not. Every 15 days after sowing (DAS), rhizospheric soil was collected for soil microbial respiration (amount of evolved CO 2) and microbial biomass carbon (MBC) analysis. To determine herbicide residues in the soil samples, after phytoremediation, Sorghum bicolor L. was cultivated as an indicator species, in addition to high performance liquid chromatography (HPLC) analysis. The microbiota associated to S. aterrimum rhizosphere showed to be sensitive to trifloxysulfuron-sodium and may be used as a microbiological indicator of disturbances caused by this herbicide in the environment. Regarding time for remediation, 45 days of development is enough for S. aterrimum to reduce residual trifloxysulfuron- sodium to a level not able to cause toxicity to the indicator plant.

Avaliação da função glomerular de cães sadios e nefropatas sob estimulação dopaminérgica

Dopamine is an endogenous compound widely used in intensive care. It has a broad spectrum of action, on the cardiovascular system and urinary tract. Increased glomerular filtration rate, renal blood flow and fractional excretion of sodium and phosphorus are expected renal effects in normal individuals, but are poorly explored in veterinary medicine. This study was conducted to evaluate the glomerular function of dogs with renal disease submitted to continuous infusion of dopamine. Different doses of dopamine were administered in healthy and nephropathic dogs. Laboratory evaluations of creatinine clearance and urinary protein/creatinine ratio were performed during and after treatments. Creatinine clearance showed dose-dependent increase in healthy dogs. In dogs with renal disease, the dose of 1μg/kg/min GFR increased slightly, without changing the urine P/C and blood pressure, while the dose of 3μg/kg/min increased urinary protein excretion.

Tolerância de Espécies de Mucuna a Herbicidas Utilizados na Cultura da Cana-de-Açúcar

The emergence of Mucuna species in sugarcane plantations, even after herbicide spraying for weed management, allowed us to elaborate the hypothesis that these plants are tolerant to the herbicides commonly used in the culture. Thus, to prove this hypothesis, this work was carried out to study the tolerance of Mucuna aterrima, Mucuna cinerea and Mucuna deeringiana to application of herbicides with different mechanisms of action in pre- and postemergence. The experiment was arranged in a randomized block design with 9 treatments and five replications in a factorial 3 × 3, plus controls. At pre-emergence, the first factor was constituted by the herbicides sulfentrazone (800 g ha-1), imazapic (245 g ha-1), and amicarbazone (1,400 g ha-1), and the second factor by the Mucuna species, besides the additional control for each species studied. At post- emergence, the herbicides tested were clomazone (1,100 g ha-1), ametryn+trifloxysulfuronsodium (1,463 + 37 g ha-1), and 2,4-D (1,209 g ha-1). In the chemical management at pre-emergence, the species were sensitive to amicarbazone, followed by sulfentrazone, and tolerant to imazapic. At post-emergence, all species were sensitive to ametryn + trifloxysulfuron-sodium and 2,4-D, but tolerant to clomazone.

Thermal stability of ionene polymers

Two different cationic polymers of the same chemical type and with very similar chemical structures were reacted with a natural bentonite over a wide range of polymer/clay ratios. This study involved the synthesis of cationic aliphatic ammonium polyionenes, specifically 3,6-ionene and 3,6-dodecylionene. Ionenes are ion-containing polymers that contain quaternary nitrogen atoms in the main macromolecular chain as opposed to a pendant chain. The CHN content, basal spacing, and elemental composition of each of the polymer-clay complexes were analyzed by X-ray diffraction, X-ray fluorescence, and thermogravimetry. All the polycations reacted to form interlayer complexes with clay, which displaced more Na+ and little Ca2+. Sodium and calcium were both present as interlayer cations in the clay and its complexes. The TG/DTG curves show that both polymers underwent thermal degradation in more than one stage. Specifically, 3,6-ionene was found to undergo two stages of decomposition and 3,6-dodecylionene undergo three stages. The behavior of the TG/DTG curves and the activation energy values suggest that 3,6-dodecylionene (E = 174,85 kJ mol-1) complexes have greater thermal stability than 3,6-ionene (E = 115,52 kJ mol-1) complexes. The mechanism of degradation suggests a direct interaction with the dodecyl chain containing 12 carbons, which are present in 3,6-dodecylionene but not in 3,6-ionene. © 2012 Akadémiai Kiadó, Budapest, Hungary.