The following new articles have just been published in Veterinary ResearchFor articles which have only just been published, you will see a 'provisional PDF' corresponding to the accepted manuscript. A fully formatted PDF and full text (HTML) version will be made available soon. | ||||
| Research Veterinary Research 2011, 42:69 (23 May 2011) [Abstract] [Provisional PDF] [PubMed] | ||||
| Research Veterinary Research 2011, 42:68 (23 May 2011) [Abstract] [Provisional PDF] [PubMed] | ||||
| Research Veterinary Research 2011, 42:66 (18 May 2011) [Abstract] [Provisional PDF] [PubMed] | ||||
| Research Veterinary Research 2011, 42:65 (18 May 2011) [Abstract] [Provisional PDF] [PubMed] | ||||
| Research Veterinary Research 2011, 42:64 (18 May 2011) [Abstract] [Provisional PDF] [PubMed] | ||||
| Research Veterinary Research 2011, 42:63 (11 May 2011) [Abstract] [Provisional PDF] [PubMed] | ||||
| Research Veterinary Research 2011, 42:62 (11 May 2011) [Abstract] [Provisional PDF] [PubMed] | ||||
| Research Veterinary Research 2011, 42:61 (11 May 2011) [Abstract] [Provisional PDF] [PubMed] | ||||
| Research Veterinary Research 2011, 42:60 (20 April 2011) [Abstract] [Full Text] [PDF] [PubMed] | ||||
| Research Veterinary Research 2011, 42:59 (20 April 2011) [Abstract] [Full Text] [PDF] [PubMed] | ||||
| Research Veterinary Research 2011, 42:57 (14 April 2011) [Abstract] [Full Text] [PDF] [PubMed] | ||||
| Review Veterinary Research 2011, 42:67 (18 May 2011) [Abstract] [Provisional PDF] [PubMed] | ||||
| Short report Veterinary Research 2011, 42:58 (14 April 2011) [Abstract] [Full Text] [PDF] [PubMed] | ||||
| You currently receive Veterinary Research article alerts whenever new articles are published To change the email format or frequency, to update your email address or to stop receiving these alerts, visit http://www.veterinaryresearch. |
quinta-feira, 26 de maio de 2011
Latest Article Alert from Veterinary Research (13 articles)
Medo do dentista: terapia é melhor do que anestesia geral
Fobia dental
Pessoas com fobia de dentista muitas vezes precisam recorrer a algum tipo de anestesia geral para que possam ter seus dentes tratados.
Mas estão surgindo alternativas eficazes.
Pesquisadores europeus decidiram então comparar essas alternativas, para se certificarem de qual delas é a melhor.
Tratamentos para fobia dental
Em um estudo prático, ele compararam a eficácia e a aceitação da hipnose padrão, da hipnose com imagens individualizadas, do tratamento cognitivo-comportamental e da anestesia geral no tratamento da fobia dental.
De um grupo inicial de 137 pacientes com fobia dental, 77 completaram o estudo, resultando em amostras entre 14 e 29 pacientes em cada um dos quatro grupos.
Os participantes preencheram questionários destinados a medir a ansiedade odontológica no início do estudo, antes e depois da primeira consulta odontológica, e novamente antes da segunda sessão de tratamento dental, uma semana depois.
Terapia cognitivo-comportamental
A hipnose padrão mostrou-se significativamente inferior ao tratamento cognitivo-comportamental, resultando na interrupção prematura do tratamento por reações do paciente.
A análise final mostrou uma redução significativa da ansiedade dental com o tratamento cognitivo-comportamental e com a hipnose individualizada - bem superior à anestesia geral.
Analisando as intenções dos pacientes em retomar o tratamento após a primeira sessão, foi registrada uma melhoria significativa apenas após a terapia cognitivo-comportamental.
Os resultados sugerem que a terapia cognitivo-comportamental é o melhor tratamento para a fobia dental quando se leva em conta tanto a eficácia quanto a aceitabilidade pelos pacientes.
Composto do cogumelo do sol impede câncer de próstata
Prevenção do câncer
Um cogumelo conhecido por seus benefícios culinários e medicinais mostrou-se 100 por cento eficaz na supressão do desenvolvimento do tumor de próstata.
Os pesquisadores descobriram que um composto extraído do cogumelo do sol (Yun zhi), o polissacaropeptídeo (PSP), alveja diretamente as células-tronco do câncer de próstata e suprime a formação do tumor.
A pesquisa, realizada em modelos animais, foi realizada na Universidade de Tecnologia de Queensland, na Austrália, e publicada na revista científica PLoS ONE.
Células-tronco do câncer
O Dr. Patrick Ling, coordenador da pesquisa, afirma que os resultados representam um passo importante para o combate à doença que é uma das principais causas de morte entre os homens.
"Os resultados são bastante significativos", disse o Dr. Ling. "O que queríamos era demonstrar, antes de tudo, que esse composto pode parar o desenvolvimento de tumores de próstata.
"No passado, outros inibidores testados em pesquisas mostraram-se até 70 por cento eficazes, mas estamos vendo uma eficácia de 100 por cento na prevenção do tumor com o PSP." diz ele.
As terapias convencionais só são eficazes com relação a determinadas células cancerosas, mas não às células-tronco do câncer, que iniciam e fazem a doença progredir.
Via oral
O pesquisador ressalta que, nos testes feitos até agora, não foi observado nenhum efeito colateral.
Apesar dos cogumelos terem propriedades valiosas para a saúde, o Dr. Ling afirma que não seria possível obter o mesmo benefício em relação ao câncer de próstata simplesmente comendo-os.
Brasileiro descobre anticorpo que indica doença autoimune rara
Neuromielite óptica recorrente
A neuromielite óptica recorrente (NMO) é uma doença autoimune que causa inflamação dos nervos ópticos e da medula espinhal, podendo levar à cegueira e à paralisia.
É uma doença rara e, por conta da falta de estudos na área, costuma ter um diagnóstico tardio, quando já deixou sequelas graves.
O neurologista Tarso Adoni, a Faculdade de Medicina da Universidade de São Paulo (USP), analisou a presença do anticorpo NMO-IgG, um dos indicativos da doença, nos pacientes já diagnosticados.
Suas conclusões poderão aumentar a qualidade de vida dos portadores da síndrome.
Anticorpo
A análise, orientada pelo professor Dagoberto Callegaro, envolveu 28 pacientes. Destes, 64,5% apresentaram o NMO-IgG, estatística semelhante a de outros países do mundo.
"Quando um portador da NMO apresenta um sintoma, como uma diminuição abrupta da acuidade (precisão) visual, muitas vezes não se consegue identificar o motivo e ele pode permanecer sem diagnóstico até que novos episódios aconteçam.
"Com a descoberta de que uma parcela expressiva dos pacientes possui o anticorpo, faz-se um teste em busca dele. Ao encontrá-lo, a doença é detectada antes de alguma consequência mais grave, como perda da visão ou paralisia", explica o pesquisador.
Imunossupressores
Apesar de não ter cura, a NMO tem tratamento.
Se diagnosticada precocemente, pode ser tratada antes de uma nova manifestação e a pessoa pode ter uma vida normal.
Adoni enfatiza que o tratamento é feito por meio de medicamentos imunossupressores, que deixam o sistema de defesa do organismo mais inofensivo, evitando que ataque a si próprio.
Este tratamento tem que ser feito durante todo o período de vida do paciente.
O médico explica que pode haver casos de pacientes que não respondam aos imunosupressores da maneira esperada, mas que tais casos constituem-se em uma exceção.
Doença rara
Ao analisar os dados, Adoni percebeu que a idade média de manifestação da doença nos pacientes foi de 28 anos. Em outros países, a média se mantém em torno dos 36 anos.
O médico acredita que essa diferença pode ter sido constatada por causa do pequeno número de pessoas observadas, ou realmente a doença se manifesta mais cedo na população brasileira. Somente um estudo com um maior número de pessoas poderia sanar essa dúvida.
O que dificulta é a raridade da doença: no Japão, onde ela é mais comum, os casos variam entre 20 e 30 a cada 100 mil habitantes. A doença também atinge principalmente mulheres negras e jovens, na faixa dos 20 aos 40 anos, mas ainda não há explicação para esse fato.
Doenças autoimunes
O estudo também aponta que a presença do anticorpo NMO-IgG é um marcador de que os portadores da NMO têm uma pré-disposição maior a outras doenças autoimunes. Muitos deles tiveram problemas com a tireoide, por exemplo.
O teste de detecção do anticorpo NMO-IgG pode fazer a diferença na vida de um portador da neuromielite óptica, mas por enquanto só está disponível em um laboratório particular em São Paulo, e custa em torno de R$300,00.
Alguns serviços públicos estão desenvolvendo a técnica pelo Brasil e o SUS, em algumas situações especiais, faz convênio com o Estado e paga pelo exame.
Suplemento com aminoácido e vitamina diminui pré-eclâmpsia
Pré-eclâmpsia
Um suplemento dietético que contém um aminoácido e vitaminas antioxidantes, administrado a mulheres grávidas com alto risco de pré-eclâmpsia, pode reduzir a ocorrência da condição.
A pré-eclâmpsia é uma condição grave, quando uma pressão sanguínea anormalmente elevada e outros distúrbios surgem durante a gravidez.
Ela afeta cerca de 5% de todas as primeiras gravidezes e é perigosa para a mãe e para a criança.
Acredita-se que a pré-eclâmpsia esteja associada a uma deficiência de L-arginina, um aminoácido que ajuda a manter um fluxo sanguíneo saudável durante a gravideza.
Alguns especialistas também acreditam que as vitaminas antioxidantes podem ajudar a proteger contra a doença.
Suplemento contra a pré-eclâmpsia
Agora, uma equipe de pesquisadores no México e nos Estados Unidos começou a testar a teoria de que uma combinação de L-arginina e antioxidantes poderia impedir o desenvolvimento da pré-eclâmpsia em mulheres com alto risco da doença.
As mulheres grávidas com alto risco de pré-eclâmpsia foram divididas aleatoriamente em três grupos: 228 receberam barras de alimentação diária contendo L-arginina, vitaminas e antioxidantes, 222 receberam barras contendo apenas vitaminas, e 222 receberam placebo (sem L-arginina e sem vitaminas).
Os suplementos começaram a ser administrados na vigésima semana de gravidez, prosseguindo até o parto. A pressão arterial e os níveis de L-arginina foram medidos a cada três a quatro semanas no hospital.
A proporção de mulheres que apresentaram a pré-eclâmpsia foi de 30,2% no grupo placebo, 22,5% no grupo somente vitamina, e de 12,7% no grupo de vitamina mais L-arginina.
Isto significa que as mulheres no grupo da vitamina mais L-arginina tiveram uma probabilidade significativamente menor de desenvolver a pré-eclâmpsia em comparação com o grupo placebo.
Somente com as vitaminas, a ocorrência de pré-eclâmpsia teve uma redução menos significativa.
Prevenção do parto prematuro
A equipe também descobriu que a combinação de L-arginina e vitaminas reduziu significativamente o risco de parto prematuro, em comparação com o placebo.
"Esta intervenção relativamente simples e de baixo custo pode ser valiosa na redução do risco de pré-eclâmpsia e da prematuridade associada à condição," concluem os autores.
No entanto, eles dizem que mais estudos são necessários para determinar se esses resultados podem ser repetidos e identificar se eles são devidos à L-arginina isoladamente ou à combinação de L-arginina, vitaminas e antioxidantes.
O estudo foi publicado no site do British Medical Journal.
Scientists Recreate Brain Cell Networks Providing View of Activity Behind Memory Formation
ScienceDaily (May 25, 2011) — University of Pittsburgh researchers have reproduced the brain's complex electrical impulses onto models made of living brain cells that provide an unprecedented view of the neuron activity behind memory formation.
 |
A fluorescent image of the neural network model developed at Pitt reveals the interconnection (red) between individual brain cells (blue). Adhesive proteins (green) allow the network to be constructed on silicon discs for experimentation. |
The team fashioned ring-shaped networks of brain cells that were not only capable of transmitting an electrical impulse, but also remained in a state of persistent activity associated with memory formation, said lead researcher Henry Zeringue [zuh-rang], a bioengineering professor in Pitt's Swanson School of Engineering. Magnetic resonance images have suggested that working memories are formed when the cortex, or outer layer of the brain, launches into extended electrical activity after the initial stimulus, Zeringue explained. But the brain's complex structure and the diminutive scale of neural networks mean that observing this activity in real time can be nearly impossible, he added.
The Pitt team, however, was able to generate and prolong this excited state in groups of 40 to 60 brain cells harvested from the hippocampus of rats -- the part of the brain associated with memory formation. In addition, the researchers produced the networks on glass slides that allowed them to observe the cells' interplay. The work was conducted in Zeringue's lab by Pitt bioengineering doctoral student Ashwin Vishwanathan, who most recently reported the work in the Royal Society of Chemistry (UK) journal, Lab on a Chip. Vishwanathan coauthored the paper with Zeringue and Guo-Qiang Bi, a neurobiology professor in Pitt's School of Medicine. The work was conducted through the Center for the Neural Basis of Cognition, which is jointly operated by Pitt and Carnegie Mellon University.
To produce the models, the Pitt team stamped adhesive proteins onto silicon discs. Once the proteins were cultured and dried, cultured hippocampus cells from embryonic rats were fused to the proteins and then given time to grow and connect to form a natural network. The researchers disabled the cells' inhibitory response and then excited the neurons with an electrical pulse.
Zeringue and his colleagues were able to sustain the resulting burst of network activity for up to what in neuronal time is 12 long seconds. Compared to the natural duration of .25 seconds at most, the model's 12 seconds permitted an extensive observation of how the neurons transmitted and held the electrical charge, Zeringue said.
Unraveling the mechanics of this network communication is key to understanding the cellular and molecular basis of memory creation, Zeringue said. The format developed at Pitt makes neural networks more accessible for experimentation. For instance, the team found that when activity in one neuron is suppressed, the others respond with greater excitement.
"We can look at neurons as individuals, but that doesn't reveal a lot," Zeringue said. "Neurons are more connected and interdependent than any other cell in the body. Just because we know how one neuron reacts to something, a whole network can react not only differently, but sometimes in the complete opposite manner predicted."
Zeringue will next work to understand the underlying factors that govern network communication and stimulation, such as the various electrical pathways between cells and the genetic makeup of individual cells.
Improving Health Assessments With a Single Cell: Portable Microchip for Immune Monitoring and Clinical Applications
ScienceDaily (May 25, 2011) — There's a wealth of health information hiding in the human immune system. Accessing it, however, can be very challenging, as the many and complex roles that the immune system plays can mask the critical information that is relevant to addressing specific health issues. Now, research led by scientists from the California Institute of Technology (Caltech) has shown that a new generation of microchips developed by the team can quickly and inexpensively assess immune function by examining biomarkers -- proteins that can reflect the response of the immune system to disease -- from single cells.
 |
A small sample of a patient's blood contains both white and red blood cells (bottom left). The white blood cells are comprised of many different cell types, each of which perform various functions that together represent the activity of the immune system. A thousand or so single immune cells of defined types are captured on the single cell barcode chip (middle left) and their functional behavior read out by recording the levels of a dozen functional, secreted proteins for each captured cell. The resultant information, which is contained in the many barcodes shown in the image at right, provides a rich and detailed view into the status of the patient's immune system. |
The scientists reported on their advanced technology in the May 22 online issue of Nature Medicine.
"The technology permits us for the first time to quantitatively measure the levels of many functional proteins from single, rare immune cells," says James Heath, the Elizabeth W. Gilloon Professor and professor of chemistry at Caltech and corresponding author of the study. "The functional proteins are the ones that are secreted by the cells, and they control biological processes such as cell replication and inflammation and, specific to our study, tumor killing."
In 2008, Heath -- an expert in molecular electronics and personalized medicine -- led the development of a "barcode chip" that, using just a pinprick's worth of blood, could measure the concentrations of dozens of proteins, including those that herald the presence of diseases like cancer and heart disease. This latest single-cell barcode chip (SCBC) device builds upon the success of that initial design, which is currently being utilized in diagnostic medical testing of certain cancer patients.
The researchers tested the chip by measuring a cancer patient's response to a type of cell-based immunotherapy designed to target and kill tumor cells. The only way to know if the therapy is doing its job is to measure many proteins at the same time from the individual cells that were targeting the tumor. The SCBC aced this test, generating readouts of a dozen secreted biomarkers -- each of which represented a distinct cell function -- and taking those readings from about a thousand single cells simultaneously.
The team was able to conduct a proof-of-concept study by looking at samples from a melanoma patient participating in the immunotherapy trials, and comparing those results to similar samples from three healthy subjects.
"This technology has the potential to be used routinely to monitor immune system performance," says Chao Ma, a graduate student in Heath's lab at Caltech's NanoSystems Biology Cancer Center and lead author of the Nature Medicinepaper. "For example, it can be directly used to evaluate the effectiveness of certain classes of therapeutics, such as vaccines and other immunotherapies."
According to Ma, the technology is minimally invasive, cost-effective, and highly informative. The goal, he says, is to help physicians closely track the effectiveness of a therapy, and to rapidly alter or switch that therapy for the maximum benefit of the patient.
"The research fully demonstrates real-life clinical use of our revolutionary technology," Ma says.
The next step for the team will be to systematically apply the technology to clinical studies. The researchers have already begun to test the technology in additional patient populations, and to combine the SCBC with existing assays in order to get a more comprehensive picture of a therapy's efficacy.
In fact, the same study that showed the microchip's efficacy is already helping the researchers better evaluate the specific cancer immunotherapy trial, from which the patient in the study was drawn. "We are doing these same types of measurements on similar patients but at a significantly higher level of detail, and at many time points over the course of the cancer immunotherapy procedure," explains Heath. "It is helping us put together a 'movie' of the patient's immune system during the therapy, and it is providing us with some very surprising but also valuable insights into how the therapy works and how we might work with our UCLA colleagues to improve it."
"Application of this technology provides an unprecedented understanding of the human immune system by allowing an efficient and multiplexed functional readout of immune responses using limiting numbers of lymphocytes," says Antoni Ribas, associate professor of medicine and physician who led the clinical trial portion of the study at UCLA's Jonsson Comprehensive Cancer Center.
The other Caltech authors of the Nature Medicine paper, "A clinical microchip for evaluation of single immune cells reveals high functional heterogeneity in phenotypically similar T cells," are postdoctoral scholar Qihui Shi; Rong Fan, former postdoctoral scholar; former graduate students Habib Ahmad and Gabriel Kwong; and Chao-Chao Liu, former undergraduate student. Begonya Comin-Andiux, assistant professor of surgery; Thinle Chodon, assistant researcher of medicine; Richard C. Koya, assistant professor of surgery; and Caius G. Radu, associate professor of medical and molecular pharmacology from UCLA's Jonsson Comprehensive Cancer Center also contributed to the study.
The work was funded by the National Cancer Institute, the Ivy Foundation, the Jean Perkins Foundation, the California Institute for Regenerative Medicine, the Caltech/UCLA Joint Center for Translational Medicine, the Melanoma Research Alliance, and the National Institutes of Health.
Long-Term Study of Swine Flu Viruses Shows Increasing Viral Diversity
ScienceDaily (May 25, 2011) — Although swine influenza viruses usually sicken only pigs, potentially one might also spark a pandemic in people, as occurred with the 2009 H1N1 influenza virus. Because few long-term studies have surveyed flu viruses in swine, however, gaps exist in what is known about the evolution of swine influenza viruses and the conditions that enable a swine virus to infect humans and cause disease. Increased transportation of live pigs appears to have driven an increase in the diversity of swine influenza viruses found in the animals in Hong Kong over the last three decades, according to a new study.
 |
The gene flow of influenza A viruses occurs among birds, pigs and humans. |
In the longest study of its kind, Duke-NUS Graduate Medical School researchers found that swine viruses crossed geographic borders and mixed with local viruses, increasing their diversity.
"The majority of reported human infections have been people with close contact to farm animals," said Vijaykrishna Dhanasekaran, Ph.D., an assistant professor at Duke-NUS, who works in the Laboratory of Virus Evolution.
"I think the risk of swine-to-human transmission has not increased greatly, but the diversity of swine viruses has increased as shown in our study," Vijaykrishna said. "This means that the repertoire of viruses that humans are in contact with everyday has increased and this may lead to a higher likelihood of swine-to-human transmission, although the risk remains unquantified."
The study was published online in the journal Nature on May 25.
"The geographic transport of swine viruses that we highlight in our study is likely through the transport of live pigs," Vijaykrishna said. "Most swine viruses that have been described to date have been isolated from farmed pigs in Asia, Europe and North America. Some viruses have been isolated from backyard pigs in southeast Asia. However, no information is available on status of influenza in naturally roaming wild or domestic pigs."
The study looked at the epidemiology, genetics and antigenic properties of swine influenza virus in Hong Kong from more than 650 samples taken from swine, more than 800 swine blood specimens from 12 years of surveillance, and 34 years worth of other data on swine flu viruses. Antigens are the features on the surface of the virus that pigs and humans develop antibodies against to fight the infection. Influenza viruses evade the immune response by mutations in the hemagglutinin protein, an attachment protein that serves as an antigen. Antibodies formed during previous infections fail to recognize the newly mutated antigen, which is why seasonal influenza vaccines have to be reformulated each year.
Mutations in the swine influenza hemagglutinin have been linked to reassortment, which is the mixing of genetic material from multiple virus species into new combinations, said Vijaykrishna. The greater viral diversity they found in the swine flu viruses may mean more possible combinations from reassortment.
"These results provide important clues into the mechanism of influenza virus evolution in general," he said.
The researchers discovered that two major lineages of H1 subtype viruses and the human H3N2 viruses were frequently detected in swine. Several combinations of the three lineages were detected in pigs, including some avian (bird) viruses.
While the pigs had no symptoms or very mild undetected symptoms to most viruses isolated for the study, the scientists don't know how virulent these viruses can be in humans. "It is important to monitor viruses in swine, especially those that can emerge in humans that we do not have antibodies for," said Vijaykrishna, who is a faculty member of the Duke-NUS Program on Emerging Infectious Diseases.
Vijaykrishna and Gavin Smith at the Laboratory of Virus Evolution (LoVE) at Duke-NUS conducted the genetic analyses with Dr. Oliver Pybus at Oxford University. The swine surveillance used data on swine specimens collected over 34 years, and the laboratory work was done by the University of Hong Kong.
The work was supported in part by the U.S. National Institute of Allergy and Infectious Diseases (NIAID) and the Area of Excellence Scheme of the University Grants Commission of the Hong Kong SAR Government. The Food and Environmental Hygiene Department of Hong Kong facilitated the study. The authors also note the support of the Royal Society of London, UK COSI, and the Agency for Science, Technology and Research and the Ministry of Health, Singapore.
Assinar:
Postagens (Atom)
