Aumenta o número de casos de doença transmitida por gatos

No período de janeiro de 2001 a agosto de 2006, os casos de esporotricose - micose transmitida pelo fungo Sporothrix schenckii por meio da arranhadura de gatos - aumentaram no Estado do Rio de Janeiro, de acordo com Margarete Bernardo Tavares da Silva, autora da dissertação de mestrado Distribuição sócio-espacial da esporotricose humana de pacientes atendidos no Instituto de Pesquisa Clínica Evandro Chagas no período de 1997 a 2007, residentes no Estado do Rio de Janeiro. O estudo analisou 1.848 casos, com média de 168 destes por ano. Resultados comprovaram que gatos, em ambiente domiciliar e ao mesmo tempo em contato com a natureza, são fatores de risco para contaminação por esporotricose.

Em algumas áreas urbanas tem sido registrada a ocorrência de casos de esporotricose relacionados à arranhadura ou mordedura de animais como o gato

De acordo com Margarete Silva, que também é pesquisadora do Ipec, uma das unidades técnico-científicas da Fiocruz, foram confirmados 1.107 casos de esporotricose humana, diagnosticados a partir de atendimento ambulatorial no serviço de referência de estudos clínicos de micoses. A média de notificação anual, entre 2001 e 2005, foi de 184 casos/ano. Segundo a pesquisadora, a esporotricose é uma micose subaguda ou crônica causada, na maior parte dos casos, por implantação traumática do fungo Sporothrix schenckii. Esta micose tem se tornado um grave problema de saúde pública no Estado do Rio de Janeiro devido ao aumento significativo de casos humanos nos últimos anos.

Orientado pelas pesquisadoras Rosely Magalhães de Oliveira e Maria Clara Gutierrez Galhardo, a pesquisa apontou que, historicamente, a esporotricose esteve associada a profissionais que lidam com a terra, local onde o fungo causador da doença é encontrado. No entanto, recentemente, em algumas áreas urbanas tem sido registrada a ocorrência de casos relacionados à arranhadura ou mordedura de animais como o gato, levando a surtos familiares, acometendo indivíduos de todas as faixas etárias e sexo, sem que haja necessidade de fatores individuais predisponentes.

De acordo com a autora, o estudo buscou entender a distribuição da esporotricose humana relacionada às condições sociais, ambientais e comportamentais existentes em determinadas localidades. Tais condições determinam a variação na transmissão e manutenção da doença na área de estudo. Segundo Margarete, o Boletim Epidemiológico do Serviço de Vigilância em Saúde do Ipec de 2007 mostra que, no período de janeiro de 2001 a agosto de 2006, foram confirmados 1.107 casos de esporotricose humana, diagnosticados a partir de atendimento ambulatorial no serviço de referência de estudos clínicos de micoses. A média de notificação anual, entre 2001 e 2005, foi de 184 casos/ano, apontando um aumento no número de notificações ao longo dos anos. "Desde 2003, a média foi ultrapassada em direção ascendente. Em 2006, os dados até agosto, já ultrapassavam a média dos anos anteriores. Estes dados podem não refletir a realidade da doença em todo o Estado do Rio de Janeiro, mas esta informação nos permite afirmar que ela vem aumentando com o passar dos anos", ressaltou.

A autora pôde concluir que o desconhecimento sobre a doença e os cuidados necessários para evitar a contaminação contribuíram para a manutenção dos casos ao longo desses anos. Além disso, a orientação, o tratamento e a castração desses animais são um dos caminhos para o controle da doença. Segundo Margarete, há uma enorme necessidade de realização de estudos científicos que determinem a transcendência econômica e social desta epidemia para o real conhecimento da situação epidemiológica da esporotricose humana no Rio de Janeiro, sendo necessária a instituição da esporotricose como doença de notificação compulsória em nível estadual.

Bem-Estar Animal - Pequenos brinquedos, grandes resultados

Nanopartículas liberam medicamento direto na célula cancerosa

Após a administração, as nanopartículas podem ser orientadas para os tecidos cancerosos utilizando um campo magnético e localizadas por intermédio de ressonância magnética.

Nanopartículas

Um projeto de pesquisa que está em desenvolvimento no Laboratório de Polímeros da Escola de Engenharia de Lorena (EEL), da USP, teve como principal objetivo encontrar materiais inteligentes e não-tóxicos, que liberem medicamentos de forma controlada diretamente nas células cancerosas.

O estudo da engenheira química Simone de Fátima Medeiros avaliou a síntese de nanopartículas poliméricas magnéticas, sensíveis à variação de temperatura e de pH, constituídas de polímero, copolímero e ácido acrílico, e óxido de ferro.

De acordo com Simone, a novidade é que os polímeros podem ser utilizados como agentes de encapsulação de drogas hidrofílicas (solúveis em água).

Durante o preparo, tanto a droga como as partículas magnéticas (óxido de ferro) são encapsuladas por matrizes poliméricas sensíveis a estímulos, através de técnicas de polimerização em meio disperso e de métodos que utilizam polímeros pré-formados.

Hipertermia

A engenheira explica que, após a administração, as nanopartículas podem ser orientadas para os tecidos cancerosos utilizando um campo magnético e localizadas por intermédio da técnica de Imagem por Ressonância Magnética (IRM).

Posteriormente, estas nanopartículas são aquecidas pela exposição do tumor a um campo magnético alternado de alta frequência.

Neste processo, conhecido como hipertermia, a temperatura das células tumorais é aumentada até cerca de 45 a 55 ºC. Nesta faixa de temperatura é esperado um aumento das interações físicas do polímero, acarretando a expulsão da droga contida em seu interior.

Desta forma, a hipertermia também pode ser utilizada para promover a liberação do princípio ativo de maneira localizada e controlada, mantendo a sua concentração constante durante um período de tempo prolongado.

A eliminação da droga no local do tumor poupa o paciente dos efeitos colaterais agressivos dos tratamentos convencionais, como a quimioterapia, que tem doses concentradas de drogas que agem não só nas células doentes, mas também nas células sadias de todo o corpo, o que debilita o paciente e em alguns casos impossibilita a continuidade do tratamento.

Outro benefício de se utilizar o óxido de ferro nesta técnica, segundo Simone, é que ele também possui potencial para produzir avanços importantes no diagnóstico por imagem.

"Dessa forma, a imunolocalização de células tumorais com o uso de nanopartículas de óxido de ferro permite obter a detecção precoce de tumores via a técnica de Imagem por Ressonância Magnética" afirma Simone.

Nanocarregadores

Nas últimas décadas, partículas constituídas de polímeros vêm sendo utilizadas na área biomédica como agentes para diagnóstico in vitro.

Neste contexto, o uso de partículas magnéticas pode oferecer importantes vantagens, em comparação a outros sistemas poliméricos clássicos devido à sua rápida e fácil separação sob a aplicação de um campo magnético externo.

No entanto, a pesquisa de Simone visa à obtenção de materiais que possam ser utilizados, principalmente, para aplicações biomédicas in vivo - inicialmente em animais de laboratório.

"Para esta aplicação, os nanocarregadores devem ser constituídos de substâncias biocompatíveis, ou seja, não podem causar distúrbios no organismo vivo". Um composto biocompatível deve gerar mínima alteração homeostática e deve participar de vias metabólicas de eliminação.

Para dar continuidade ao seu projeto, Simone pretende desenvolver diferentes métodos para incorporação de nanopartículas de óxido de ferro na matriz polimérica termo-sensível, focando na obtenção de sistemas totalmente biocompatíveis, avaliáveis para aplicações biomédicas in vivo.

O grupo procura agora parcerias com farmacêuticos e médicos do Brasil, que queiram dar continuidade aos testes laboratoriais in vivo, com os materiais desenvolvidos por Simone.

Groundbreaking Technology Will Revolutionize Blood Pressure Measurement

ScienceDaily (Feb. 20, 2011) — In a scientific breakthrough, a new blood pressure measurement device is set to revolutionise the way patients' blood pressure is measured. The new approach, invented by scientists at the University of Leicester and in Singapore, has the potential to enable doctors to treat their patients more effectively because it gives a more accurate reading than the current method used. It does this by measuring the pressure close to the heart -- the central aortic systolic pressure or CASP.

This is the CASPro blood pressure measurement device.

Blood pressure is currently measured in the arm because it is convenient however this may not always accurately reflect what the pressure is in the larger arteries close to the heart.

The new technology uses a sensor on the wrist to record the pulse wave and then, using computerised mathematical modelling of the pulse wave, scientists are able to accurately read the pressure close to the heart. Patients who have tested the new device found it easier and more comfortable, as it can be worn like a watch.

Being able to measure blood pressure in the aorta which is closer to the heart and brain is important because this is where high blood pressure can cause damage. In addition, the pressure in the aorta can be quite different from that traditionally measured in the arm. The new technology will hopefully lead to better identification of those who will most likely benefit from treatment by identifying those who have a high central aortic systolic pressure value. This will be especially important for younger people in whom the pressure measured in the arm can sometimes be quite exaggerated compared to the pressure in the aorta.

A key question is whether measurement of central aortic pressure will become routine in clinical practice. Professor Williams said: "it is not going to replace what we do overnight but it is a big advance. Further work will define whether such measurements are preferred for everybody or whether there is a more defined role in selective cases to better decide who needs treatment and who doesn't and whether the treatment is working optimally"

The University's close collaboration with the Singapore-based medical device company HealthSTATS International ("HealthSTATS") has led to the development of this world-first technique for more accurate blood pressure measurement.

The research work carried out by the University of Leicester was funded by the Department of Health's National Institute for Health Research (NIHR). The NIHR has invested £3.4million with a further £2.2million Capital funding from the Department of Health to establish a Biomedical Research Unit at Glenfield Hospital, Leicester, dedicated to translational research in cardiovascular research. The work, led by Professor Bryan Williams, Professor of Medicine at the University of Leicester and consultant physician at University Hospitals of Leicester NHS Trust, has the promise to change the way we measure blood pressure.

Professor Williams, who is based in the University of Leicester's Department of Cardiovascular Sciences at Glenfield Hospital, said: "I am under no illusion about the magnitude of the change this technique will bring about. It has been a fabulous scientific adventure to get to this point and it will change the way blood pressure has been monitored for more than a century. The beauty of all of this, is that it is difficult to argue against the proposition that the pressure near to your heart and brain is likely to be more relevant to your risk of stroke and heart disease than the pressure in your arm.

"Leicester is one of the UK's leading centres for cardiovascular research and is founded on the close working relationship between the University and the Hospitals which allows us to translate scientific research into patient care more efficiently. Key to our contribution to this work has been the support from the NIHR without which we would not have been able to contribute to this tremendous advance. The support of the NIHR has been invaluable in backing us to take this project from an idea to the bedside. Critical to the success of this project has been the synergies of combining clinical academic work here with HealthSTATS and their outstanding medical technology platform in Singapore. This has been the game-changer and I really do think this is going to change clinical practice."

Dr. Choon Meng Ting the Chairman and CEO of HealthSTATS said: "This study has resulted in a very significant translational impact worldwide as it will empower doctors and their patients to monitor their central aortic systolic pressure easily, even in their homes and modify the course of treatment for BP-related ailments. Pharmaceutical companies can also use CASP devices for clinical trials and drug therapy. All these will ultimately bring about more cost savings for patients, reduce the incidences of stroke and heart attacks, and save more lives."

Health Secretary Andrew Lansley said: "I saw this new technique in action in Leicester when I visited a few months ago. This is a great example of how research breakthroughs and innovation can make a real difference to patients' lives. We want the NHS to become one of the leading healthcare systems in the world and our financial commitment to the National Institute for Health Research reflects this.

"I believe patients deserve the best treatments available and science research like this helps us move closer to making that happen."

Professor Dame Sally Davies, Director General of Research and Development and Interim Chief Medical Officer at the Department of Health, said:

"This is fantastic work by Professor Williams and his team and I am delighted to welcome these findings. I am particularly pleased that the clinical research took place at the NIHR Biomedical Research Unit in Leicester. NIHR funding for Biomedical Research Centres and Units across England supports precisely this type of translational research, aimed at pulling-through exciting scientific discoveries into benefits for patients and the NHS by contributing to improved diagnostics and treatments."

New High-Resolution Method for Imaging Below the Skin Using a Liquid Lens

ScienceDaily (Feb. 20, 2011) — University of Rochester optics professor Jannick Rolland has developed an optical technology that provides unprecedented images under the skin's surface. The aim of the technology is to detect and examine skin lesions to determine whether they are benign or cancerous without having to cut the suspected tumor out of the skin and analyze it in the lab. Instead, the tip of a roughly one-foot-long cylindrical probe is placed in contact with the tissue, and within seconds a clear, high-resolution, 3D image of what lies below the surface emerges.

This prototype device developed by University of Rochester Professor of Optical Engineering Jannick Rolland can take high-resolution images under the skin's surface without removing the skin. Researchers say that in the future .it may eliminate the need for many biopsies to detect skin cancer

Rolland presented her findings at the 2011 annual meeting of the American Association for the Advancement of Science in Washington, D.C., on Feb. 19.

"My hope is that, in the future, this technology could remove significant inconvenience and expense from the process of skin lesion diagnosis," Rolland says. "When a patient walks into a clinic with a suspicious mole, for instance, they wouldn't have to have it necessarily surgically cut out of their skin or be forced to have a costly and time-consuming MRI done. Instead, a relatively small, portable device could take an image that will assist in the classification of the lesion right in the doctor's office."

The device accomplishes this using a unique liquid lens setup developed by Rolland and her team for a process known as Optical Coherence Microscopy. In a liquid lens, a droplet of water takes the place of the glass in a standard lens. As the electrical field around the water droplet changes, the droplet changes its shape and therefore changes the focus of the lens. This allows the device to take thousands of pictures focused at different depths below the skin's surface. Combining these images creates a fully in-focus image of all of the tissue up to 1 millimeter deep in human skin, which includes important skin tissue structures. Because the device uses near infrared light instead of ultrasounds, the images have a precise, micron-scale resolution instead of a millimeter-scale resolution.

The process has been successfully tested in in-vivo human skin and several papers on it have been published in peer-reviewed journals. Rolland says that the next step is to start using it in a clinical research environment so its ability to discriminate between different types of lesions may be assessed.

Rolland joined the faculty of the Hajim School of Engineering and Applied Science's Institute of Optics in 2009. She is the Brian J. Thompson Professor of Optical Engineering and is also a professor of biomedical engineering and associate director of the R.E. Hopkins Center for Optical Design and Engineering.

Efficacy of Tuberculosis Vaccine Enhanced Thanks to New Research

ScienceDaily (Feb. 19, 2011) — Nele Festjens and Nico Callewaert of VIB and Ghent University have improved the efficacy of the vaccine for tuberculosis. The new vaccine affords -- as already proven in mice -- better protection against the disease. The development of a new tuberculosis vaccine is a priority in the fight against the disease which claims the lives of 1.7 million people each year. The current vaccine provides only partial protection.

Nico Callewaert: "Our vaccine is more effective because it is more quickly recognized by the immune system of the vaccinated person. We have, as it were, undressed the existing vaccine by removing its protective shield."

Tuberculosis: a worldwide problem

One third of the world population is infected with the Mycobacterium tuberculosis bacterium which causes tuberculosis (TB). TB, AIDS and malaria are the three infectious diseases claiming the largest number of fatalities worldwide. The World Health Organization (WHO) estimates that each year 8 to 10 million people become infected. TB is in particular a disease of the poor and mainly affects young adults in their most productive years. Most TB fatalities are in the developing countries, more than half of them in Asia. In almost all of these countries, multidrug-resistant TB is becoming increasingly frequent. This form of TB is very hard to treat.

Prevention is better than cure

TB treatments are expensive and also very difficult because of multidrug-resistant TB. There has therefore been a strong focus on vaccination in the fight against TB. The only vaccine on the market is Bacillus Calmette-Guérin (BCG). It is produced from attenuated live bovine tuberculosis bacterium, Mycobacterium bovis, which has lost its virulence in humans. In children, the vaccine prevents only half of cases of tuberculosis and in adolescents and adults the degree of protection is much lower still.

In recent years, several other candidate vaccines have been developed and some of these have been tested on humans. Only a few have led to a moderate improvement in protection compared with the BCG vaccine. The search for a more efficient vaccine is therefore still on.

Removing the bacterium's defense shield

The bacterium from which the BCG vaccine is derived hides as it were from the immune system of the organism in which it ends up. This may well be the reason why the vaccine is not very effective. The fact is that a vaccine is meant to trigger an immune reaction in order to be able to afford good protection. Nele Festjens and Nico Callewaert have discovered that the bacterium hides behind the SapM enzyme that acts as a kind of shield.

They have used this knowledge to develop a new vaccine. They adapted Mycobacterium bovis BCG in such a way that it was no longer able to generate SapM and could therefore no longer hide from the immune system. Testing the new vaccine on mice has shown that it affords better protection than the present BCG vaccine.

A different mechanism

The researchers also demonstrated that their vaccine works in a way different from the other vaccines currently being tested. In fact, it acquires its extra protective value by emitting signals that provoke inflammation and in this way activate the right cells of the immune system. Festjens and Callewaert are convinced that applying their strategy -- removing the protective shield -- in the new vaccines that are somewhat better than the vaccine currently being marketed should lead to a vaccine that affords genuine protection against TB.

Conventional Wisdom of How Neurons Operate Challenged: Axons Can Work in Reverse

ScienceDaily (Feb. 19, 2011) — Neurons are complicated, but the basic functional concept is that synapses transmit electrical signals to the dendrites and cell body (input), and axons carry signals away (output). In one of many surprise findings, Northwestern University scientists have discovered that axons can operate in reverse: they can send signals to the cell body, too.

Computer-generated image representing connections between neurons. 

It also turns out axons can talk to each other. Before sending signals in reverse, axons can perform their own neural computations without any involvement from the cell body or dendrites. This is contrary to typical neuronal communication where an axon of one neuron is in contact with another neuron's dendrite or cell body, not its axon. And, unlike the computations performed in dendrites, the computations occurring in axons are thousands of times slower, potentially creating a means for neurons to compute fast things in dendrites and slow things in axons.

A deeper understanding of how a normal neuron works is critical to scientists who study neurological diseases, such as epilepsy, autism, Alzheimer's disease and schizophrenia.

The findings are published in the February issue of the journalNature Neuroscience.

"We have discovered a number of things fundamental to how neurons work that are contrary to the information you find in neuroscience textbooks," said Nelson Spruston, senior author of the paper and professor of neurobiology and physiology in the Weinberg College of Arts and Sciences. "Signals can travel from the end of the axon toward the cell body, when it typically is the other way around. We were amazed to see this."

He and his colleagues first discovered individual nerve cells can fire off signals even in the absence of electrical stimulations in the cell body or dendrites. It's not always stimulus in, immediate action potential out. (Action potentials are the fundamental electrical signaling elements used by neurons; they are very brief changes in the membrane voltage of the neuron.)

Similar to our working memory when we memorize a telephone number for later use, the nerve cell can store and integrate stimuli over a long period of time, from tens of seconds to minutes. (That's a very long time for neurons.) Then, when the neuron reaches a threshold, it fires off a long series of signals, or action potentials, even in the absence of stimuli. The researchers call this persistent firing, and it all seems to be happening in the axon.

Spruston and his team stimulated a neuron for one to two minutes, providing a stimulus every 10 seconds. The neuron fired during this time but, when the stimulation was stopped, the neuron continued to fire for a minute.

"It's very unusual to think that a neuron could fire continually without stimuli," Spruston said. "This is something new -- that a neuron can integrate information over a long time period, longer than the typical operational speed of neurons, which is milliseconds to a second."

This unique neuronal function might be relevant to normal process, such as memory, but it also could be relevant to disease. The persistent firing of these inhibitory neurons might counteract hyperactive states in the brain, such as preventing the runaway excitation that happens during epileptic seizures.

Spruston credits the discovery of the persistent firing in normal individual neurons to the astute observation of Mark Sheffield, a graduate student in his lab. Sheffield is first author of the paper.

The researchers think that others have seen this persistent firing behavior in neurons but dismissed it as something wrong with the signal recording. When Sheffield saw the firing in the neurons he was studying, he waited until it stopped. Then he stimulated the neuron over a period of time, stopped the stimulation and then watched as the neuron fired later.

"This cellular memory is a novelty," Spruston said. "The neuron is responding to the history of what happened to it in the minute or so before."

Spruston and Sheffield found that the cellular memory is stored in the axon and the action potential is generated farther down the axon than they would have expected. Instead of being near the cell body it occurs toward the end of the axon.

Their studies of individual neurons (from the hippocampus and neocortex of mice) led to experiments with multiple neurons, which resulted in perhaps the biggest surprise of all. The researchers found that one axon can talk to another. They stimulated one neuron, and detected the persistent firing in the other unstimulated neuron. No dendrites or cell bodies were involved in this communication.

"The axons are talking to each other, but it's a complete mystery as to how it works," Spruston said. "The next big question is: how widespread is this behavior? Is this an oddity or does in happen in lots of neurons? We don't think it's rare, so it's important for us to understand under what conditions it occurs and how this happens."

In addition to Spruston and Sheffield, other authors of the paper are Tyler K. Best and William L. Kath, from Northwestern, and Brett D. Mensh, from Harvard Medical School.