Tomuleasa C.,Ion Chiricuta Comprehensive Cancer Center |
Tomuleasa C.,University of Medicine and Pharmacy, Cluj-Napoca |
Soritau O.,Ion Chiricuta Comprehensive Cancer Center |
Brie I.,Ion Chiricuta Comprehensive Cancer Center |
And 9 more authors.
Journal of B.U.ON. | Year: 2010
Purpose: The purpose of this study was to challenge current knowledge on the potential therapeutic advantages of stem cells in radiotherapy by developing an in vitro model of the healthy tissue surrounding or replacing the widely resected tumor. After radical surgery, the start of radiotherapy is often delayed due to wound healing process, with potential loss of the opportunity for treating microscopic disease instead of macroscopic early recurrence. Hyperfractionated radiotherapy, contrary to the standard one, can extend the limits of radical surgery and shorten the gap before the onset ofpostoperative radiotherapy, with potential improvement in local control. Methods: By using both mesenchymal stem cells and pre-differentiated osteoblasts, cultured in proper pro-osteogenic media after cell irradiation, we investigated both the differences in the response to DNA damage between lineages undergoing differentiation in culture and the intensity of the mineralization process. Results: Ionizing radiation stimulated stem cell proliferation and differentiation at 0.5 Gy and 1 Gy, thus confirming in vitro the clinical results of hyperfractionated irradiation randomized trials in head and neck cancers (HNCs). Conclusion: To our knowledge, this study is the first to investigate the biophysics of low dose gamma irradiation on stem cell culture, focusing on the potential applications in radiation oncology. For advanced oral cavity and oropharyngeal cancers, as radical surgery often implies major bone resection, the use of mesenchymal stem cells as bone reconstruction vectors might shorten the onset of adjuvant hyperfractionated radiotherapy which enhances the mineralization process. As postoperative radiotherapy has recently being revisited for osteosarcoma, this scenario could impact also on bone reconstruction process in this pathology. © 2010 Zerbinis Medical Publications. Source
Lefkaditis M.,Laboratory of Microbiology and Parasitology |
Koukeri S.,Veterinary Clinic |
Cozma V.,University of Veterinary Medicine
Helminthologia | Year: 2010
Summary: Following an examination conducted on a population of three hundred and forty-one dogs living on the eastern foothills of Mt Olympus in Northern Greece, 17.9 % were found to be seropositive for the Dirofilaria immitis specific antigen. These results indicate that the region is an endemic area for the above-mentioned parasitosis in dogs. Serum samples were examined using the PetChek kit Snap (IDDEX Laboratories, ELISA, Portland USA) according to the manufacturer's instructions. With respect to gender, age and type of coat, the statistical analysis has shown that the prevalence of seropositive results is significantly higher (P < 0.05) among male dogs, older dogs and short-haired dogs. As regards breed and size, the same study has recorded a higher prevalence in mixed breed and small-sized dogs. © 2010 Parasitological Institute of SAS. Source
A pygmy slow loris (Nycticebus pygmaeus) in its natural habitat. The picture was taken in the Cuc Phuong National Park in Vietnam. More Hibernation is well-documented in a number of animal species, and is common across the mammal family tree. In primates, however, it's almost unheard of. Until recently, the only primates known to hibernate were Madagascar lemurs. But scientists have found another primate that settles down for a seasonal snooze: the pygmy slow loris, native to Vietnam. Researchers conducted the first-ever study of hibernation in pygmy slow lorises (Nycticebus pygmaeus), working with six adult animals at Vietnam's Endangered Primate Rescue Center. The researchers were looking for evidence such as reduced body temperature for extended periods of time, occurring in otherwise healthy animals. They built nesting boxes to mimic the tree holes that the lorises typically use for hibernating, and implanted the lorises with devices that logged their temperatures every 6 minutes for nearly a year. During the cool, dry winter months, from late October until early April, the lorises exhibited behavior and physical responses consistent with animals that are known hibernators. They would repeatedly retreat to their nesting boxes and lapse into periods of inactivity that lasted up to 63 consecutive hours at a time, the researchers said. While in hibernation, their temperatures would dip to about 52 degrees Fahrenheit (11 degrees Celsius). [In Photos: Cute New Slow Loris Species] The animals' bodies would also be stiff to the touch, said the study's corresponding author, Thomas Ruf, a physiologist with the University of Veterinary Medicine in Vienna. Ruf told Live Science that he had suspected for some time that lorises hibernated, based on accounts dating back to the 1980s. Those reports described lorises curled up in trees, where they remained inactive for days. But without monitoring the animals over time, it was impossible to tell whether this was a sign of hibernation or of illness, Ruf added. The data gathered by Ruf and his colleagues provided the first evidence that the lorises entered a state of inactivity and reduced metabolic rate in response to seasonal changes, the new study reported. Hibernation is an effective survival strategy for animals living in parts of the world where changing seasons mean that food is less available for parts of the year. Pygmy slow lorises eat fruit and insects, and when winter rolls around, the insects become scarce. "That's why we think they hibernate — they have to save energy somehow," Ruf said. Another benefit of hibernation is that the drop in body temperature means that animals' natural body odors are reduced, making the creatures harder for predators to detect, Ruf said. He recalled an experiment from decades ago that "you couldn't do these days," in which hibernating mice were placed in a room with hungry weasels. Because the mice were cold, motionless and stiff, the weasels weren't interested and left the potential prey alone. Likewise, lorises hibernating in trees would be easy prey for snakes, but a cold, stiff, loris doesn't have much appeal to predators looking for a warm, lively dinner. "Hibernation is a very safe time for animals," Ruf told Live Science. "They have a very high survival probability." Small wonder, then, that so many animals hibernate. In mammals, hibernation appears in 11 different orders, which suggests the behavior originated far back in the ancestral time line of mammals. "It's unlikely that it evolved independently among so many genetic branches, " Ruf said. "So it must be really old." It's possible that more hibernating species are yet to be discovered, even in the primate lineage, where hibernation is considered rare. Hibernating lemurs and the pygmy slow loris all belong to the same suborder, Strepsirrhini, and more species in that grouping could be hibernators, too, the researchers said. "I suspect there are more primates that hibernate," Ruf added. "Now we have to go and look." The findings were published online Dec. 3 in the journal Scientific Reports. Follow Mindy Weisberger on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science. Copyright 2015 LiveScience, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Elrike Frenzel, Markus Kranzler and Monika Ehling-Schulz of the Institute of Microbiology at the University of Veterinary Medicine Vienna have now shown for the first time that B. cereus has an alternative lifestyle in the form of so called small colony variants (SCVs). In B. cereus these SCVs form in response to exposure with aminoglycoside antibiotics. SCVs grow slower than the original form of B. cereus. They have an altered metabolism and are resistant to those antibiotics which triggered this state, namely aminoglycosides. "The bacterium protects itself against the harmful effects of the antibiotics by forming these Small Colony Variants. But B. cereus is usually treated with exactly those antibiotics which induce the SCV state. If an antibiotic triggers the formation of SCVs, it also triggers resistance," first author Frenzel explains. The mechanism discovered by Frenzel, Kranzler and Ehling-Schulz is of enormous significance in clinical practice. Traditional diagnostic methods are based on the identification of metabolic features of B. cereus. These tests will not detect SCVs, however, as they have a slower, altered metabolism. This may result in incorrect antibiotic therapies or even failed diagnoses. Study author Frenzel sees molecular-based diagnostics as the only way to diagnose this form of B. cereus. Treating B. cereus infections using only aminoglycoside antibiotics could bear the risk of a prolonged infection. SCVs grow more slowly, but they still produce toxins that are harmful to the body. "In this case, a combination therapy with other antibiotic groups is advisable," Frenzel recommends. One species of bacteria that has been known for years to be a multiresistant hospital pathogen and which poses a life-threatening risk for immunocompromised individuals in particular is Staphylococcus aureus. Those bacteria also form SCVs, but unlike B. cereus they are capable of reverting to its original state. For B. cereus, the adaptation to a small colony variant appears to be final. "We believe that the SCV formation in B. cereus functions differently than in S. aureus," says study author Ehling-Schulz. "The ability to form SCVs appears to be of environmental significance for the bacteria," Frenzel believes. "This alternative lifestyle allows the bacteria to avoid threatening stress factors such as antibiotic exposure. B. cereus are soil-dwelling, and other microorganism in the soil produce antibiotics. Here, too, the formation of SCVs would be an advantage for the bacteria." Explore further: Molecular basis for Pseudomonas aeruginosa persistent infections in CF patients More information: Elrike Frenzel et al. The Endospore-Forming Pathogen Exploits a Small Colony Variant-Based Diversification Strategy in Response to Aminoglycoside Exposure , mBio (2015). DOI: 10.1128/mBio.01172-15
The pygmy slow loris truly hibernates, making it the first primate outside Madagascar found to do so, a new study says. “Up until now there were only three species of primate known to hibernate: All lemurs in Madagascar,” says Thomas Rufof the University of Veterinary Medicine in Vienna. But in Vietnam, new measurements of wintertime body temperature for pygmy slow lorises (Nycticebus pygmaeus) show bouts of chilly torpor lasting as long as 63 hours. A plunge in metabolic rate for more than 24 hours counts as hibernation, Ruf says. There was talk about whether some unique conditions in Madagascar allowed the evolution of primate hibernation only there, Ruf says. But he and his colleagues dismiss that scenario December 3 in Scientific Reports.