Parasitism of a capybara (Hydrochoerus hydrochaeris) by Amblyomma nodosum Neumann, 1899 and Amblyomma humerale Koch, 1844 in an Amazon forest area, Rondônia, Brazil / [Parasitismo por Amblyomma nodosum Neumann, 1899 e Amblyomma humerale Koch, 1844 em capivara (Hydrochoerus hydrochaeris) em área de Floresta Amazônica, Rondônia, Brasil]

Dois carrapatos adultos, sendo um Amblyomma nodosum e um Amblyomma humerale foram encontrados parasitando ativamente uma capivara (Hydrochoerus hydrochaeris) proveniente da região central do estado de Rondônia, Brasil, na zona rural do município de Ji-Paraná, localizado na Amazônia ocidental. Poucos trabalhos científicos relatam a presença de A. humerale em capivaras. Assim, esta é a primeira vez que A. nodosum é relatado parasitando essa espécie animal. Por não se tratar de um hospedeiro animal conhecido para A. nodosum ou comum para A. humerale, esses achados podem sugerir uma nova relação entre hospedeiros para eles. Portanto, são necessários mais estudos acerca da ecologia desses parasitas, principalmente por serem potenciais transmissores de patógenos de importância em medicina veterinária e saúde pública.(AU)

Effects of short-term administration of estradiol on reperfusion arrhythmias in rats of different ages

Little is known about age-related differences in short-term effects of estradiol on ischemia-reperfusion (I/R) insults. The present study was designed to evaluate the effects of short-term treatment with estradiol on reperfusion arrhythmias in isolated hearts of 6-7-week-old and 12-14-month-old female rats. Wistar rats were sham-operated, ovariectomized and treated with vehicle or ovariectomized and treated with 17β-estradiol (E2; 5 µg·100 g-1·day-1) for 4 days. Hearts were perfused by the Langendorff technique. Reperfusion arrhythmias, i.e., ventricular tachycardia and/or ventricular fibrillation, were induced by 15 min of left coronary artery ligation and 30 min of reperfusion. The duration and incidence of I/R arrhythmias were significantly higher in young rats compared to middle-aged rats (arrhythmia severity index: 9.4 ± 1.0 vs 3.0 ± 0.3 arbitrary units, respectively, P < 0.05). In addition, middle-aged rats showed lower heart rate, systolic tension and coronary flow. Four-day E2 treatment caused an increase in uterine weight. Although E2 administration had no significant effect on the duration of I/R arrhythmias in middle-aged rats, it induced a marked reduction in the rhythm disturbances of young rats accompanied by a decrease in heart rate of isolated hearts. Also, this reduction was associated with an increase in QT interval. No significant changes were observed in the QT interval of middle-aged E2-treated rats. These data demonstrate that short-term estradiol treatment protects against I/R arrhythmias in hearts of young female rats. The anti-arrhythmogenic effect of estradiol might be related to a lengthening of the QT interval.

Anticonvulsant and antiarrhythmic effects of nifedipine in rats prone to audiogenic seizures

Calcium ion participates in the regulation of neural transmission and the presynaptic release of neurotransmitters. It is also involved in epileptic events, cardiac arrhythmias and abnormal conduction of stimuli. The purpose of the present study was to evaluate the effects of nifedipine, a calcium channel blocker, on epileptic seizures and on reperfusion arrhythmias in rats prone to audiogenic epileptic seizures (Wistar audiogenic rats, WAR) and in normal Wistar rats (N = 6/group). The seizure severity index was applied after an intraperitoneal injection of 20 or 40 mg/kg nifedipine (N20 and N40 groups, respectively). The Langendorff technique was used to analyze cardiac function, as well as the incidence and severity of the reperfusion arrhythmias after ligature and release of the left coronary artery in rats treated or not with nifedipine. We found that nifedipine treatment decreased seizure severity (0.94 ± 0.02 for WAR; 0.70 ± 0.10 for WAR + N20; 0.47 ± 0.08 for WAR + N40) and increased the latent period (13 ± 2 s for WAR; 35 ± 10 s for WAR + N20; 48 ± 7 s for WAR + N40) for the development of seizures in WAR. Furthermore, the incidence and severity of the reperfusion arrhythmias were lower in WAR and normal Wistar rats injected with nifedipine. In WAR, these effects were mediated, at least in part, by a decrease in heart rate. Thus, our results indicate that nifedipine may be considered to be a potential adjuvant drug for epilepsy treatment, especially in those cases associated with cardiac rhythm abnormalities.

Suscetibilidade a antimicrobianos e produção de betalactamase em amostras de Staphylococcus isolados de mastite caprina no semiárido paraibano / Susceptibility to antimicrobial drugs and production of beta-lactamase by Staphylococcus strains isolated from mastitis in goats in the semi-arid region of Paraiba state, Brazil

Este trabalho teve como objetivo avaliar a susceptibilidade antimicrobiana in vitro e a produção de betalactamase de 42 amostras de Staphylococcus isolados de mastite subclínica caprina. Foram utilizados 14 Staphylococcus chromogenes, 10 S. waneri, 6 S. saprophyticus, 5 S. aureus, 3 S. epidermidis, 2 S. intermedius e 2 Staphylococcus coagulase negativo. Os maiores índices de resistência foram para penicilina 66,67% e ampicilina 63,89% e sensibilidade frente a cefoxitina 97,62%. A múltipla resistência a 3 ou mais antimicrobianos foi observada em 42,86% dos isolados. Das 42 amostras de Staphylococcus avaliadas, 73,81% foram positivas para o teste de produção de betalactamase. A concentração inibitória mínima apresentou 100% das amostras susceptíveis à norfloxacina e os valores de resistência para os demais antimicrobianos não ultrapassaram os 30%. A alta resistência apresentada para penicilina e ampicilina demonstra a limitação no uso desses antimicrobianos no tratamento da mastite caprina na região. Embora neste estudo as cefalosporinas tenham apresentado boa sensibilidade, o uso desses fármacos em medicina veterinária se torna preocupante devido à incidência de estirpes produtoras de betalactamase.

The present study was aimed to test the in vitro antimicrobial susceptibility using disc diffusion assay and minimum inhibitory concentration (MIC) values, as well as the production of beta-lactamase of 42 strains of Staphylococcus sp. isolated from subclinical mastitis in goats in the semi-arid region of Paraiba state, in Brazil. To this end, 14 samples of negative Staphylococcus chromogenes, 10 S. waneri, 6 S. saprophyticus, 5 S. aureus, 3 S. epidermidis, 2 S. intermedius and 2 Staphylococcus were used. Regarding the in vitro susceptibility, the highest levels of resistance observed concerned penicillin (66.67%) and ampicillin (63.89%), and the greatest sensitivity observed concerned Cefoxitin (97.22%). Multiple resistance to 3 or more antimicrobial drugs was observed in 42.86% of the isolates. Of the total Staphylococcus isolated, 73.81% were positive for the beta-lactamase production test. The minimum inhibitory concentration showed 100% of the samples susceptible to norfloxacin, and the maximum resistance values to the other antimicrobial drugs were 30%. According to the results obtained, it is concluded that, in order to select the most appropriate drug to treat mastitis in goats caused by strains of Staphylococcus, the antimicrobial sensitivity profile of the strain must be known and routine laboratory tests for detecting beta-lactamase should be performed because these enzymes are disseminated both in human and veterinary medicine. The high resistance to penicillin and ampicillin demonstrates the limitation in the use of antibiotics in the treatment of mastitis in goats. Although in the present study the cephalosporines demonstrated a considerable degree of sensitivity, the use of these antimicrobial agents in veterinary medicine becomes a matter of concern due to the incidence of strains that produce betalactamase.

Efeito do consumo de óleo de linhaça e de vitamina E no desempenho e nas características de carcaças de frangos de corte / Effect of linseed oil and vitamin E consumption on poultry performance and carcass traits

Foi avaliado o efeito da utilização de óleo de linhaça na ração, em substituição ao óleo de soja em diferentes proporções, e de vitamina E, até o nível de 400mg/kg de ração, sobre o desempenho e a composição de carcaça de frangos de corte. O desempenho produtivo foi avaliado com base em pesagens das aves e da ração aos 21 e 49 dias de idade. No 49º dia, as aves foram abatidas, e os rendimentos de carcaça e dos principais cortes comerciais e a porcentagem de vísceras e de gordura abdominal foram avaliados. A composição da fração oleosa da ração, de forma geral, não interferiu nos parâmetros de desempenho avaliados (P>0,05). Os machos consumiram mais ração e ganharam mais peso que as fêmeas (P<0,01). As fêmeas apresentaram, em geral, pior conversão alimentar, associada à maior deposição de gordura abdominal. Os machos apresentaram maior porcentagem de coxa com sobrecoxa em relação ao peso da carcaça eviscerada, e as fêmeas apresentaram maior porcentagem de peito. A porcentagem de asas e vísceras não diferiu entre os sexos.

The effect of the utilization of linseed oil at different concentrations in poultry feed instead of soy oil and the effect of vitamin E administration up to 400mg/kg feed on performance and carcass traits of broilers was investigated. Productive parameters were determined by weighting birds and rations at 21 and 49 days of experiment. Broilers were slaughtered on the 49th day of the experiment for the evaluation of yields of carcass and main cuts, percentages of viscera and abdominal fat. The oil composition of rations did not influence the performance of the broilers (P>0.05). Male broilers had higher feed consumption and weight gain (P<0.05). Female broilers showed worse feed conversion and higher deposition of abdominal fat (P<0.05). Male broilers also had higher percentages of legs and forelegs in relation the weight of the eviscerated carcass while females showed higher breast percentage (P<0.05). Percentages of wings and viscera did not differ between genders (P>0.05).

Angiotensin-(1-7) improves the post-ischemic function in isolated perfused rat hearts

We evaluated the effects of angiotensin-(1-7) (Ang-(1-7)) on post-ischemic function in isolated hearts from adult male Wistar rats perfused according to the Langendorff technique. Local ischemia was induced by coronary ligation for 15 min. After ischemia, hearts were reperfused for 30 min. Addition of angiotensin II (Ang II) (0.20 nM, N = 10) or Ang-(1-7) (0.22 nM, N = 10) to the Krebs-Ringer perfusion solution (KRS) before the occlusion did not modify diastolic or systolic tension, heart rate or coronary flow (basal values for Ang-(1-7)-treated hearts: 0.72 ± 0.08 g, 10.50 ± 0.66 g, 216 ± 9 bpm, 5.78 ± 0.60 ml/min, respectively). During the period of occlusion, the coronary flow, heart rate and systolic tension decreased (values for Ang-(1-7)-treated hearts: 2.83 ± 0.24 ml/min, 186 ± 7 bpm, 6.95 ± 0.45 g, respectively). During reperfusion a further decrease in systolic tension was observed in control (4.95 ± 0.60 g) and Ang II-treated hearts (4.35 ± 0.62 g). However, in isolated hearts perfused with KRS containing Ang-(1-7) the further reduction of systolic tension during the reperfusion period was prevented (7.37 ± 0.68 g). The effect of Ang-(1-7) on the systolic tension was blocked by the selective Ang-(1-7) antagonist A-779 (2 nM, N = 9), by the bradykinin B2 antagonist HOE 140 (100 nM, N = 10), and by indomethacin pretreatment (5 mg/kg, ip, N = 8). Pretreatment with L-NAME (30 mg/kg, ip, N = 8) did not change the effect of Ang-(1-7) on systolic tension (6.85 ± 0.61 g). These results show that Ang-(1-7) at low concentration (0.22 nM) improves myocardial function (systolic tension) in ischemia/reperfusion through a receptor-mediated mechanism involving release of bradykinin and prostaglandins

Angiotensin-(1-7) potentiates the coronary vasodilatatory effect of bradykinin in the isolated rat heart

It has been shown that angiotensin-(1-7) (Ang-(1-7)) infusion potentiates the bradykinin (BK)-induced hypotensive response in conscious rats. The present study was conducted to identify Ang-(1-7)-BK interactions in the isolated rat heart perfused according to the Langendorff technique. Hearts were excised and perfused through the aortic stump under a constant flow with Krebs-Ringer solution and the changes in perfusion pressure and heart contractile force were recorded. Bolus injections of BK (2.5, 5, 10 and 20 ng) produced a dose-dependent hypotensive effect. Ang-(1-7) added to the perfusion solution (2 ng/ml) did not change the perfusion pressure or the contractile force but doubled the hypotensive effect of the lower doses of BK. The BK-potentiating Ang-(1-7) activity was blocked by pretreatment with indomethacin (5 mg/kg, ip) or L-NAME (30 mg/kg, ip). The Ang-(1-7) antagonist A-779 (50 ng/ml in Krebs-Ringer) completely blocked the effect of Ang-(1-7) on BK-induced vasodilation. These data suggest that the potentiation of the BK-induced vasodilation by Ang-(1-7) can be attributed to the release of nitric oxide and vasodilator prostaglandins through an Ang-(1-7) receptor-mediated mechanism.

Effect of angiotensin-(1-7) on reperfusion arrhythmias in isolated rat hearts

There is increasing evidence that angiotensin-(1-7) (Ang-(1-7) is an endogenous biologically active component of the renin-angiotensin system (RAS). In the present study, we investigated the effects of Ang-(1-7) on reperfusion arrhythmias in isolated rat hearts. Isolated rat hearts were perfused with two different media, i.e., Krebs-Ringer (2.52 mM CaCl2) and low-Ca2+ Krebs-Ringer (1.12 mM Cacl2) and low-Ca2+ Krebs-Ringer (1.12 mM CaCl2). In hearts perfused with Krebs-Ringer, Ang-(1-7) produced a concentration-dependent (27-210 nM) reduction in coronary flow (25 percent reduction at highest concentration), while only slight and variable changes in contaction force and heart rate were observed. Under the same conditions, angiotensin II (Ang II; 27 and 70 nM) produced a significant reduction in coronary flow (39 percent and 48 percent, respectively) associated with a significant increase in force. A decrease in heart rate was also observed. In low-Ca2+ Krebs-Ringer solution, perfusion with Ang-(1-7) or Ang II at 27 nM concentration produced similar changes in coronary flow, contraction force and heart rate. In isolated hearts perfused with normal Krebs- Ringer, Ang-(1-7) produced a significant enhancement of reperfusion arrhythmias revealed by an increase in the incidence and duration of ventricular tachycardia and ventricular fibrillation (more than 30-min duration). The faciliation of reperfusion arrhythmias by Ang-(1-7) was associated with an increase in the magnitude of the decreased force usually observed during the postischemic period. The effects of Ang-(1-7) were abolished in isolated rat hearts perfused with low-Ca2+ Krebs-Ringer. The effect of Ang II (27 nM) was similar but less pronounced than that of Ang-(1-7) at the same concentration. These results indicate that the heart is a site of action for Ang-(1-7) and suggest that this heptapeptide may be involved in the mediation of the cardiac effects of the RAS.

Cross-reactivity between hard tick antigens

1. The present study was carried out to determine the target cells and tissues for anti-tick immunoglobulins using an indirect immunohistochemical technique. 2. Sections in triplicate prepared from unfed ticks Rhipicephalus appendiculatus, R. evertsi and Amblyomma variegatum were used to assess the cross-reactivity of serum from guinea pigs naturally infested with these tick species or immunized against them. 3. The sections showed slight (+) to strong ( +) labelling of several structures in the tick body, e.g. salivary gland, gut lumen and malpighian tubules, depending on the serum used. 4. The immune serum resulting from the immunization of guinea pigs with an extract of unfed nymphs of R. appendiculatus ticks showed the most intense cross-reactivity with the sections examined

Effects of anesthetics on the incidence and duration of reperfusion arrhythmias in isolated rat heart

The present study was carried out to evaluate the effect of anesthetics on reperfusion arrhythmias. Male Wistar rats (200-300 g) were injected ip with heparin (200 IU), followed by anesthesia with thiopental (40 mg/kg), pentobarbital (30 mg/kg), urethane (1.2 g/kg), either, or halothane and sacrificed by decapitation. The isolated heart (5 to 8 per group) was perfused with Locke solution by the Langendorff method and the left coronary artery was ligated for 10 min. The incidence of reperfusion arrhythmias (100 per cent ) was similar in hearts of control and previously anesthetized rats, but the duration of the arrhythmias was significantly increased by anesthesia (5-fold with thiopental, 15-fold with pentobarbital, ether and halothane, and 30-fold with urethane). In hearts taken from unanesthetized rats and perfused with Locke solution containing anesthetics (5-7 per group), the duration of reperfusion arrhythmias decreased with thiopental (0.23 +/- 0.15 min), did not change with pentobarbital (1.14 +/- 0.26 min) and increased with urethane (16.10 +/- 5.60 min). Our results show that anesthetics alter the duration of reperfusion arrhythmias in the isolated rat heart

Thyroxin plasmal levels and sulfamethoxazol-Timetrhoprim total clearance in dogs

Os níveis plasmáticos de tiroxina (T4) foram determinados por radioimunoensaio em 9 cäes, antes da administraçäo, em dose única, via intramuscular ou intravenosa, de uma associaçäo (5:1) sulfametoxazol (SMT) - trimetropina (TMP), tendo a dose (30 mg/kg) sido calculada em relaçäo ao SMT. O clearance total (Clt) foi calculado para ambos os componentes da associaçäo após dosagem das concentraçöes sanguíneas, a intervalos regulares. Os níveis médios de T4 foram 1,01 mais ou menos 0,25 ug/dl, o Clt para o SMT e o TMP foram 1,38 mais ou menos 0,41 e 0,20 mais ou menos 0,04 l/kg/h respectivamente. Näo houve correlaçäo significativa entre os níveis de T4 e os valores de Clt para SMT ou para TMP

Oscillations of cardiac rate induced by acetylcholine in the isolated guinea pig heart

1. The effects of acetylcholine (ACh) on cardiac rate (electrocardiogram), contractile force and coronary flow recorded simultaneously were investigated in isolated guinea pig hearts perfused with Locke solution by the method of Langendorff. 2. Bolus injections of 0.5-550 nmol ACh induced oscillations of cardiac rate. These changes were not directly related to the doses of ACh injected (X**2 test, P > 0.05). 3. The presence of 10 micronM physostigmine in the Locke solution increased the number of heart rate oscillations elicited by ACh. 4. The electrocardiogram showed that the heart rate oscillations were due to wandering pacemakers, such as slow or fast junctional rhythm, and slow or fast indioventricular rhythmy, which were intermingled with sinus rhythym, A - V block or sinus bradycardia. 5. In most experiments, the increase in ventricular rate was associated with an increase in ventricular contractile force ("Bowditch Effect") and a simultaneous reduction of coronary flow. 6. The heart rate oscillations were not prevented bu reserpine or blockade of nicotinic receptors (hexamethonium plus gallamine) but were prevented blockade of muscarinic receptors with atropine. 7. We conclude that the heart rate oscillations induced by ACh are due to several electrophysiological mechanisms (automatism and/or conduction disturbances_ related to activation of muscarinic receptors

Gastric acetylcholine and histamine content of normal and Trypanosoma cruzi - infected rats

The consequences of acute Trypanosoma cruzi infection for acetylcholine and histamine levels in gastric wall and for mast cells of the stomach were studied in rats. Intraperitoneal infection with 4,000 trypomastigotes/g of a Y strain of Trypanosoma cruzi led to a 4-fold decrease in gastric acetylcholine level and to a 57 - and 15-fold increase in histamine content in the membranous and glandular regions of the rat stomach, respectively. Infection of rats with Trypanosoma cruzi also induced a 2- and 4-fold increase in mast cell numbers in the membranous and glandular regions of the muscle layer of the gastric wall, respectively, and a ganglionic inflammatory reaction with predominance of mononuclear cells. We conclude that in acutely Trypanosoma cruzi-infected rats, the reduction of acetylcholine content is due to gastric denervation and that the histamine increase might be secondary to gastric denervation and/or to an increase in the number of mast cells of the gastric wall

Efeito hipnotico e tranquilizante do triazolam no periodo pre-anestesico. / Hypnotic and tranquilizing effect of triazolam in the pre-anesthetic period

O triazolam (halcion) administrado na dose de 0,5 mg, em estudo simples cego a doentes cirurgicos, na vespera e no dia da operacao, mostrou efeito favoravel sobre os seguintes parametros: inducao, duracao, e qualidade do sono, despertares noturnos e reducao das doses de anestesicos na inducao da anestesia. Nenhum efeito colateral foi observado