Associação da ocorrência do ectima contagioso (ORF vírus) em ovinos com os cuidadores desses animais / Occurrence of the Association contagious ecthyma (ORF virus) in sheep with these animals' caregivers

A enfermidade ectima contagioso está difundida em todo o estado de São Paulo. Foram amostrados 42 (8,64%) cuidadores de animais e 444 (91,36%) ovinos (n=486). A prevalência de reagentes para vírus-neutralização foi de 67% (IC95%=62-71%) nos ovinos, e em seus cuidadores de 76% (IC95%=63-89%), sendo P=0,22, ou seja, não houve diferença estatística significativa entre as espécies. A distribuição dos títulos teve diferença estatística significativa entre as espécies, com P=0,0048. As variações de titulação foram de 0,6 a 2,1 tanto nos ovinos quanto nos seus cuidadores. Dentre os 42 cuidadores de ovinos participantes do estudo, 32 apresentaram títulos de anticorpos expressos por log10 acima de 0,6.(AU)

These diseases are all widespread in the State of São Paulo. 42 (8.64%) animal caregivers and 444 (91.36%) sheep (n=486) were sampled. The reagents Prevalence paragraph virus neutralization was 67% (95% CI = 62-71%) in sheep and 76% (95% CI = 63-89%) for caregivers, with P=0.22 not being a statistically significant difference between the species. One of the distribution titles had significant difference between statistics as species with P=0.0048. The titration variations were 0.6 to 2.1, both in sheep and their caregivers. Among the 42 sheep caregivers participating in the study, 32 had antibody securities denominated in log10 above 0.6.(AU)

Neural mass modeling of power-line magnetic fields effects on brain activity.

Neural mass models are an appropriate framework to study brain activity, combining a high degree of biological realism while being mathematically tractable. These models have been used, with a certain success, to simulate brain electric (electroencephalography, EEG) and metabolic (functional magnetic resonance imaging, fMRI) activity. However, concrete applications of neural mass models have remained limited to date. Motivated by experimental results obtained in humans, we propose in this paper a neural mass model designed to study the interaction between power-line magnetic fields (MFs) (60 Hz in North America) and brain activity. The model includes pyramidal cells; dendrite-projecting, slow GABAergic neurons; soma-projecting, fast GABAergic neurons; and glutamatergic interneurons. A simple phenomenological model of interaction between the induced electric field and neuron membranes is also considered, along with a model of post-synaptic calcium concentration and associated changes in synaptic weights Simulated EEG signals are produced in a simple protocol, both in the absence and presence of a 60 Hz MF. These results are discussed based on results obtained previously in humans. Notably, results highlight that (1) EEG alpha (8-12 Hz) power can be modulated by weak membrane depolarizations induced by the exposure; (2) the level of input noise has a significant impact on EEG power modulation; and (3) the threshold value in MF flux density resulting in a significant effect on the EEG depends on the type of neuronal populations modulated by the MF exposure. Results obtained from the model shed new light on the effects of power-line MFs on brain activity, and will provide guidance in future human experiments. This may represent a valuable contribution to international regulation agencies setting guidelines on MF values to which the general public and workers can be exposed.

Neurophysiological and behavioral effects of a 60 Hz, 1,800 µT magnetic field in humans.

The effects of time-varying magnetic fields (MF) on humans have been actively investigated for the past three decades. One important unanswered question is the potential for MF exposure to have acute effects on human biology. Different strategies have been used to tackle this question using various physiological, neurophysiological and behavioral indicators. For example, researchers investigating electroencephalography (EEG) have reported that extremely low frequency (ELF, <300 Hz) MF can increase resting occipital alpha rhythm (8-12 Hz). Interestingly, other studies have demonstrated that human motricity can be modulated by ELF MF: a reduction of anteroposterior standing balance or a decrease of physiological tremor intensity have been reported as consequences of exposure. However, the main limitation in this domain lies in the lack of results replication, possibly originating from the large variety of experimental approaches employed. Therefore, the present study aimed to investigate the effects of a 60 Hz, 1,800 µT MF exposure on neurophysiological (EEG) and neuromotor (standing balance, voluntary motor function, and physiological tremor) aspects in humans using a single experimental procedure. Though results from this study suggest a reduction of human standing balance with MF exposure, as well as an increase of physiological tremor amplitude within the frequency range associated with central nervous system contribution, no exposure effect appeared on other investigated parameters (e.g., EEG or voluntary motor control). These results suggest that 1 h of 60 Hz, 1,800 µT MF exposure may modulate human involuntary motor control without being detected in the cortical electrical activity.

Tritrichomonas fetus extracellular products decrease progressive motility of bull sperm.

Tritrichomonas fetus causes infertility and abortion in cattle; however, there is scarce information regarding the susceptibility of bovine sperm to this parasite. The objective of this study was to analyze in vitro the interaction between T. fetus and bovine sperm and to evaluate the effect of extracellular products secreted by the parasite on these reproductive cells. Sperm from five fertile bulls (Bos taurus taurus, Holstein-Friesian), selected through a Percoll gradient, adhered to T. fetus after 30min of interaction, resulting in agglutination between the two kinds of cells. Based on reverse transcription-polymerase chain reaction (RT-PCR), T. fetus continuously expressed its gene for cysteine peptidase in the presence or absence of sperm. Computer-assisted semen analysis (CASA) revealed that, after 1h incubation of sperm in T. fetus culture extract, the extracellular products secreted by the parasite decreased sperm progressive motility (P<0.05). Although T. fetus extracellular products did not lead to loss of sperm viability (P<0.05) based on the Annexin-V/propidium iodide assay, the percentage of Annexin-V fluorescein isothiocyanate-positive and propidium iodide-positive cells increased (P<0.05) during incubation of sperm in T. fetus culture extract, consistent with cellular damage. In conclusion, extracellular products secreted by T. fetus were cytotoxic to bovine sperm, as they decreased sperm progressive motility; perhaps this contributes to the pathogenesis of T. fetus-induced infertility.

Dynamics of the subthalamo-pallidal complex in Parkinson's disease during deep brain stimulation.

The dynamics of the subthalamo-pallidal complex in Parkinson's disease during deep brain stimulation (DBS) were studied using two models, a simple firing-rate model and a population-based model. We extended the simple firing-rate model of the complex formed by the subthalamic nucleus (STN) and the external segment of the Globus Pallidus (GPe) to explore its dynamical regime during DBS. More specifically, the modulation of neuronal activity (i.e., pattern and amplitude) during DBS was studied. A similar approach was used with the population-based model. Simulation results revealed a gradual decrease in bursting activity in STN cells when the DBS frequency increased. In addition, the contribution of the stimulation current type (mono- or biphasic) to the results was also examined. A comparison of the two models indicated that the population-based model was more biologically realistic and more appropriate for exploring DBS mechanisms. Understanding the underlying mechanisms of DBS is a prerequisite for developing new stimulation protocols.

New insights offered by a computational model of deep brain stimulation.

Deep brain stimulation (DBS) is a standard neurosurgical procedure used to treat motor symptoms in about 5% of patients with Parkinson's disease (PD). Despite the indisputable success of this procedure, the biological mechanisms underlying the clinical benefits of DBS have not yet been fully elucidated. The paper starts with a brief review on the use of DBS to treat PD symptoms. The second section introduces a computational model based on the population density approach and the Izhikevich neuron model. We explain why this model is appropriate for investigating macroscopic network effects and exploring the physiological mechanisms which respond to this treatment strategy (i.e., DBS). Finally, we present new insights into the ways this computational model may help to elucidate the dynamic network effects produced in a cerebral structure when DBS is applied.

Comparative bioavailability of two ramipril formulations after single-dose administration in healthy volunteers.

OBJECTIVE: To assess the bioequivalence of a ramipril 5 mg tablet formulation (ramipril test formulation from Laboratórios Biosintética Ltda (Sao Paulo, Brazil) and Triatec from Aventis Pharma (Sueano, Brazil) standard reference formulation) in 26 healthy volunteers of both sexes. METHODS: The study was conducted using an open, randomized, 2-period crossover design with a 2-week washout interval. Plasma samples were obtained over a 36-hour period. Plasma ramipril and ramiprilat concentrations were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) with positive ion electrospray ionization using multiple reaction monitoring (MRM). From the ramipril and ramiprilat plasma concentration vs. time curves, the following pharmacokinetic parameters were obtained: AUClast, AUCinf and Cmax. RESULTS: The limit of quantification was 0.2 ng x ml(-1) and 1.0 ng x ml(-1) for ramipril and ramiprilat, respectively. The geometric means and 90% confidence intervals (CI) for Ramipril/Triatec and Ramiprilat/Triatec percent ratios were: 104.69% (90% CI = 93.21-117.59%) for Cmax, 102.49% (90% CI = 92.76-113.24%) for AUClast, 103.60% (90% CI = 93.56 114.73%) for AUCinf, 108.48% (90% CI = 98.86-119.03%) for Cmax, 105.88% (90% CI = 101.55-110.39%) for AUClast, 97.30% (90% CI = 90.17-104.99%) for AUCinf, respectively. CONCLUSION: Since the 90% CI for AUClast, AUCinf and Cmax ratios were within the 80-125% interval proposed by the U.S. FDA, it was concluded that the ramipril formulation produced by Laboratórios Biosintética Ltda is bioequivalent to the Triatec formulation in both rate and extent of absorption.

Serological profile of anti-Toxoplasma gondii antibodies in apparently healthy dogs of the city of Botucatu, São Paulo State, Brazil

Toxoplasmosis is a zoonosis caused by Toxoplasma gondii, a coccidian protozoan of worldwide distribution. The seroprevalence in canine population can be an alternative for measuring T. gondii urban spreading. A total of 780 blood samples from dogs were collected, during the yearly anti-rabies campaign, carried out by the Department of Veterinary Hygiene and Public Health, School of Veterinary Medicine and Animal Husbandry (FMVZ), São Paulo State University, UNESP, together with the county health authorities, in August 1999. Using Indirect Fluorescent Antibody Test (IFAT) for detecting antibodies anti-T. gondii in the sera samples, we observed that 258 dogs (33.1 percent) were positive. The associations between the serological results and the epidemiological variables were studied. Statistically significant differences were not found regarding sex (32.2 percent male and 34.3 percent female reactors). Dogs without a defined breed showed seropositivity statistically higher than the pedigreed group. The occurrence of infection was considered higher with age.

The comparison of the Butzler medium, filtration technique and their association with isolation of Campylobacter ssp.

Campylobacter was isolated in 178 out of 622 stool samples (200 porcine, 220 bovine, and 202 canine). From these 178 samples, the microorganism was identified in 64 samples (36%) isolated only in Butzler selective medium (BSM), 34 samples (19%) using filtration technique (FT), and in 80 samples (45%) using both BSM and FT. Comparison of the proportion of positivity using both techniques showed a significant value (chi2 = 9,184; p > 0.001); BSM (36%) being more efficient than FT (19%). The use of both techniques yielded the highest isolation positivity (45%).

Ocorrência de Campylobacter em genitais de bovinos vasectomizados mantidos em central de transferência de embriöes / Occurrence of Campylobacter in the genitals of teaser bulls maintained at an embryo transfer center

Em central de transferência de embriöes, após os procedimentos de reconhecimento do cio em 37 vacas receptoras, através de quatro rufiöes vasectomizados, observou-se que 83 por cento delas apresentavam retorno ao cio e algum corrimento serofibrinoso. Nos exames bacteriológicos realizados nos lavados prepuciais dos rufiöes foi isolado o Campylobacter fetus subsp. venerealis em todos, fato que, analisado associadamente com o retorno ao cio das vacas receptoras, é indicativo da ocorrência de campilobacteriose no plantel. Essa ocorrência demonstra a necessidade de medidas eficazes de planejamento de saúde animal, pela utilizaçäo de rufiöes com desvio lateral do pênis. Uma vez impossibilitado o contato sexual, seria impedida a transmissäo do agente durante o coito. Torna-se imperioso consignar que a prática da prevençäo racional de enfermidades continua sendo o procedimento mais econômico para uma produtividade animal mais rentável

Atividade in vitro do danofloxacin e de sete drogas antimicrobianas frente a linhagens de Staphylococcus aureus isoladas de mastite bovina / Antimicrobial activity of danofloxacin and seven other drugs against Staphylococcus aureus from bovine mastitis

Duzentas estirpes mastitogênicas de Staphylococcus aureus foram submetidas à atividade antimicrobiana de oito drogas (danofloxacin, cefuroxime, ciprofloxacin, trimetoprim/sulfametoxazol, cloranfenicol, imipenem, tetraciclina e oxacilina). O danofloxacin, antimicrobiano da família das 4-fluoroquinolonas, foi recém-lançado para uso exclusivo em veterinária. O estudo comparativo das drogas antimicrobianas foi realizado pela técnica do disco (Bauer-Kirby) e da determinaçäo da concentraçäo inibitória mínima (CIM) juntamente com a avaliaçäo da concentraçäo bactericida mínima (CBM). Os resultados demonstraram que as drogas mais eficientes foram: imipenem (100 por cento), trimetoprim/sulfametoxazol (98,9 por cento), cefuroxime (97,3 por cento), tetraciclina (96,9 por cento), danofloxacin (95,4 por cento), cloranfenicol (93,9 por cento), oxacilina (93,4 por cento) e ciprofloxacin (91,1 por cento), considerando-se somente os percentuais de linhagens sensíveis. Levando-se em conta também as linhagens moderadamente sensíveis, o danofloxacin foi considerado o terceiro antimicrobiano mais eficiente. O estudo da determinaçäo da CIM e da CBM do danofloxacin caracterizou sua elevada eficiência antimicrobiana, tendo em vista a proximidade entre elas (CIM90 por cento subscrito - 0,18 µg/ml - CBM90 por cento subscrito - 0,23 µg/ml) e a relaçäo CIM/CBM de 1:1 e 1:2 para a maioria das linhagens em estudo

Avaliaçäo da sensibilidade do Califórnia Mastitis Test (CMT) e Whiteside (WS) na mastite caprina / Sensitivity of California mastitis (CMT) and Whiteside (WS) tests on the diagnosis of caprine mastitis

Considerando que uma das medidas para o controle da mastite caprina consiste, inicialmente, na determinaçäo da taxa de mastite subclínica, e também diante da importância da caprinocultura, o presente estudo teve por objetivo comparar o teste California Mastitis test (CMT) com o Whiteside (WS), utilizando-se 322 amostras de leite de cabra. Dessas, 67 (21 por cento) reagiram concomitantemente ao CMT e ao WS, 210 (65 por cento) apresentaram-se negativas para ambos os testes e 45 (14 por cento) apresentaram resultados discordantes entre os dois testes, 41 (91 por cento) delas positivas ao CMT e negativas ao WS. Os resultados permitiram apontar o CMT como o mais sensível e que, por ser mais prático, poderá trazer benefícios no planejamento do controle da mastite caprina

Gallium arsenide metal-semiconductor-metal photodiodes as optoelectronic mixers for microwave single-sideband modulation.

Gallium arsenide (GaAs) metal-semiconductor-metal (MSM) photodetectors have unique properties including high-bandwidth, linearity, and biphase response that make them suitable as mixers and programmable weights for microwave and communications applications. An optical technique for microwave single-sideband modulation that uses GaAs MSM photodiodes as mixers is reported. It uses MSM Schottky photodiodes formed in a GaAs/Al(0.3)Ga(0.7)As materials system to detect microwave in-phase and quadrature signals on optical carriers. Modulation of the photodetector bias voltages results in a single-sideband modulation of the microwave signal. Radio frequency and undesired-sideband suppression of 36 and 27 dB, respectively, were achieved. The optical wavelength was 850 nm, and the bandwidth of the photodetectors was > or = 29 GHz.

Planar, Al0.3Ga0.7As-passivated-base, heterojunction bipolar phototransistors.

New planar GaAs heterojunction bipolar phototransistors have been designed and demonstrated. The devices use a GaAs/Al(0.3)Ga(0.7) As molecular-beam-epitaxy materials system with an Al(0.3)Ga(0.7) As passivated, 10-nm-thick base; a depleted, high-low emitter; and a low emitter-base capacitance. Electrical contact to the emitter is made by a set of parallel, ohmic fingers and to the collector by an ohmic contact formed in a large, approximately 1.48-microm deep via. Rise times in response to impulse optical excitation at 810 nm were 747-891 ps except at the two lowest optical excitation powers measured. Photocurrent gains measured at 810 and 850 nm were 0.67-19, depending on experimental conditions. These devices are promising for use in heterodyne photodetector arrays for coherent optical processing channelizers requiring a 100-MHz bandwidth.

Incidência e caracterizaçäo de bactérias com resistência múltipla antimicrobiana em leite mastítico bovino da regiäo centro-oeste do Estado de Säo Paulo, Brasil / Incidence and characterization of mastitic bovine milk antimicrobial multi-drug resistant bacteria in middle west region of Sao Paulo, Brazil

Foram analisadas a incidência e a multi-resistência a drogas antimicrobianas em bactérias patogênicas isoladas de 750 amostras de leite de vacas com mastite sub-clínica, na regiäo-centro oeste do Estado de Säo Paulo. Os microorganismos do gênero Staphylococcus (75,8 por cento), principalmente representados pelos S. aureus e S. epidermes, e a Escherichia coli (7,1 por cento) foram as bactérias mais freqüentemente isoladas. A maioria dos agentes etiológicos apresentou-se em cultura pura, embora associaçöes de microorganismos tenham sido encontradas em algumas amostras. A resistência múltipla a drogas antimicrobianas (penicilina, ampicilina, dicloxacilina, estreptomicina, tetraciclina e oxacilina) foi observada somente entre bactérias Gram negativas e em algumas linhagens de S. aureus (39,9 por cento). Os demais agentes bacterianos Gram positivos demonstraram sensibilidade às drogas testadas. Os problemas conseqüentes da resistência múltipla a drogas constituem um obstáculo à terapêutica e de difícil soluçäo, principalmente através de programas de controle a curto prazo

[Oocysts of Cryptosporidium sp in feces: comparison of the modified Kinyoun and Heine methods]. / Pesquisa de oocistos de Cryptosporidium sp em fezes: comparação entre os métodos de Kinyoun modificado e de Heine.

The diagnosis of intestinal infection by Cryptosporidium sp is crucial today; with the progression of the AIDS epidemic, many cases of cryptosporidiosis have appeared in this setting and in other immunodeficiency diseases. We compared the advantages and disadvantages of Heine's method and modified Kinyoun's method in the following parameters: morphology of the parasite, quantitation of cysts, stability of the staining characteristics timewise on the slides and time spend at staining. All positive fecal smears were obtained from patients with AIDS. The sensitivity of these two techniques was the same. The choice should be made by the best aspects of each method. Heine's was better for quantitation of the cysts and was faster. Kinyoun's was better for conserving the stained smear.

Characterization of aerobic bacteria in the uterus and cervix of mares with suspected or clinical metritis

Quatrocentos e trinta éguas com metrite clínica ou suspeita foram examinadas clínica e bacteriologicamente quanto à análise comparativa entre o diagnóstico clínico e o sucesso na resposta bacteriológica. De 303 (70,4 por cento) éguas que mostraram contaminaçäo bacteriana, 172 (40 por cento) apresentaram organismos Gram negativos e 131 (30,4 por cento) bactérias Gram positivas, sendo a E. coli (n = 82), K. pneumoniae (n = 26), P. aeruginosa (n = 20), S. aureus (n = 19) e S. zooepidemicus (n = 18) os patógenos mais frequentes. Contra um conjunto de 18 agentes antimicrobianos, os microrganismos Gram-negativos mostraram resistência in vitro à maioria das drogas, enquanto que os Gram positivos (excluindo-se S. aureus e E. faecalis) foram todos sensíveis. Nitrofurantoína, sulfamethoxazol + trimethoprim e gentamicina foram os agentes de açäo antimicrobiana mais efetivos contra todas as bactérias

[The evaluation of the effect of formol and sodium hypochlorite on the demonstration of Cryptosporidium oocysts in feces by Heine's method]. / Avaliação da influência do formol e do hipoclorito de sódio na pesquisa de oocistos de Cryptosporidium nas fezes, através do método de heine.

Cryptosporidium oocysts were searched by Heine's method in stools of nine calves with cryptosporidiosis after stool treatment with two disinfectants, 10% paraformaldehyde solution and 14.5% sodium hypochlorite solution. After 30 minutes exposition to sodium hypochlorite solution oocysts became non refractile and acquired a reddish tinge, making their identification difficult. No morphological alterations occurred in oocysts after paraformaldehyde treatment. We recommend paraformaldehyde at 10% concentration as means of human immunodeficiency virus (HIV) inactivation for routine use in stool examinations and therefore making safer those type of procedures for laboratory personnel, when using Heine's method.

A practical approach for the treatment of bovine trichomoniasis

Cinco touros, naturalmente infectados com Trichomonas foetus, cada um pesando 800 kg e com idade entre seis e oito anos, foram tratados, por via intravenosa, com uma única aplicaçäo de benzoilnitroimidazole a 50 mg/kg e diluídos em três litros de soluçäo de 20 por cento de DMSO. A pesquisa microscópica a fresco e o cultivo microbiológico do protozoário revelaram-se negativos às 24 horas e 12 semanas pós-tratamento. Os touros tratados emprenharam fêmeas que levaram a gestaçäo a termo. O êxito obtido nesse procedimento terapêutico pode representar, a campo, praticidade no controle de trichomoniase bovina

Characteristics of Staphylococcus aureus from subclinical bovine mastitis in Brazil.

A total of 127 Staphylococcus aureus strains isolated from milk samples of cows with subclinical bovine mastitis was examined for biotype, phage pattern, in-vitro antibiotic susceptibilities and ability to produce enterotoxins. The majority of the strains showed features consistent with bovine rather than human origin. All strains were sensitive to the antibiotics tested, except penicillin and streptomycin. Enterotoxigenicity was observed in 6 (4.7%) strains and only enterotoxins A and C were produced.