A antitrombina de B. jararaca foi isolada por meio de cromatografia de afinidade em coluna HiTrap Heparin HP (GE Healthcare). A análise da interação da antitrombina humana ou de B. jararaca com a heparina em sistema BIAcoreT200 demonstrou que a antitrombina de B. jararaca apresenta maior afinidade pela heparina que a antitrombina humana. Com relação à sua atividade anti-inflamatória, os resultados obtidos evidenciaram o efeito anti-inflamatório do pré e do pós-tratamento com a antitrombina de B. jararaca na resposta inflamatória aguda. A análise proteômica do exsudato inflamatório de camundongos identificou algumas proteínas possivelmente relacionadas ao mecanismo de inibição da antitrombina, como a enzima C3 do sistema complemento, a sorotransferrina, a a1-antitripsina, a apolipoproteína AI, o fibrinogênio, o cininogênio e a albumina. O processo de clonagem permitiu a obtenção da sequência completa da antitrombina de B. jararaca e apesar da longa distância evolutiva entre serpentes e humanos, diversas características da antitrombina encontram-se conservadas. / B. jararaca antithrombin was isolated by affinity chromatography using HiTrap Heparin HP column (GE Healthcare). The interaction analysis of human or B. jararaca antithrombin with heparin using a BIAcoreT200 system (GE Healthcare) demonstrated that the affinity of B. jararaca antithrombin for heparin is higher than human antithrombin. Regarding the anti-inflammatory activity of B. jararaca antithrombin, the results showed the anti-inflammatory effect of pre- and post-treatment with this molecule in acute inflammation. The proteomic analysis of inflammatory exudate of mice identified some proteins possibly related to the mechanism of inhibition of antithrombin, such as C3 complement, serum transferrin, a1-antitrypsin, apolipoprotein AI, fibrinogen, albumin and kininogen. The molecular cloning process allowed the determination of the complete sequence of B. jararaca antithrombin and despite the evolutionary distance between snakes and human, a number of characteristics are preserved in antithrombin molecule.

O veneno de Philodryas patagoniensis ocasiona lesões locais importantes e similares as que ocorrem nos acidentes botrópicos. Os mecanismos envolvidos nas ações locais deste veneno são pouco conhecidos. Este estudo tem como objetivo investigar as ações locais morfológicas e inflamatórias do veneno de Philodryas patagoniensis e os mecanismos envolvidos no desenvolvimento da dor e edema, por meio de modulação farmacológica. O teor protéico total do veneno foi de 70-75% de proteínas. A análise eletroforética (SDS-PAGE 7,5-17,5%) apresentou bandas protéicas com pesos moleculares entre 62 e 14 kDa, sendo quatro majoritárias em 62, 48, 35 e 30 kDa. O edema mensurado por pletismografia foi máximo 30 min após a inoculação (53,33 ± 1,43 %), regredindo a partir da 6º hora, mostrou-se dose-dependente sendo a dose mínima edematogênica de 0,82µg e inibido em 45% por EDTA. A atividade nociceptiva foi avaliada pelo tempo (em segundos) em que os animais lambiam ou mordiam a pata injetada, e os resultados mostraram que tal atividade é dose-dependente, sendo significativamente diferente do controle e independente de metaloproteinases, uma vez que não foi inibida pelo EDTA. Através da modulação farmacológica foi possível observar que a dor causada pelo veneno foi inibida pela Indometacina, Cyproheptadina e Tramal, indicando que a mediação é por opióides, prostaglandinas e serotonina. A ação foi potencializada pelo Captopril, sugerindo a possível participação de cininas, bem como pelo L-NAME (10mg/kg). Dexametasona, Prometazina, Arcoxia, Celebra e L-NAME (50mg/kg) não interferiram nesta atividade. O edema foi inibido pela Dexametasona e Indometacina e, portanto, mediado por prostaglandinas e leucotrienos. Captopril, Tramal, Prometazina, L-NAME, Arcoxia e Celebra não foram capazes de interferir significativamente no edema. A injeção intramuscular de 30µg do veneno produziu efeitos de desorganização das fibrilas musculares, hemorragia interfibrilar, edema, infiltrado inflamatório e mionecrose dos tipos coagulativa e miolítica, as quais foram inibidas na presença de PMSF e 1-10Phenantrolina. Três, seis e 24 horas após a inoculação intra-muscular de 60µg de veneno, ocorreu um decréscimo gradativo de proteínas não-colágenas com leve redução em alguns componentes miofibrilares observados por SDS-PAGE. O infiltrado inflamatório induzido em cavidade peritoneal foi máximo três horas após a injeção e a contagem celular diferencial apresentou predominantemente leucócitos polimorfonucleares. A técnica de microscopia intravital direta demonstrou que a administração tópica de 0,1µg de veneno induziu distúrbios marcantes em vênulas pós-capilares, caracterizados por vasodilatação, lesões hemorrágicas distribuídas em focos (microsangramentos) e alterações nas interações leucócito-endotélio, tais como redução do número de leucócitos em rolling, aumento da adesão e indução da migração de células através da parede do endotélio. A inoculação subcutânea do veneno na bolsa escrotal de camundongos induziu efeitos típicos de inflamação aguda, com leucócitos migrados vistos a partir de uma hora após a inoculação, regredindo em 48 horas. O veneno age sobre mastócitos in vitro, causando degranulação e conseqüente liberação de histamina concentração dependente. Os resultados obtidos indicam o potencial inflamatório deste veneno e a cinética dos eventos sugere uma complexa sinergia de diversos efeitos, contribuindo para a severidade do quadro local nos envenenamentos. / The venom of Philodryas patagoniensis causes important and similar local lesions the ones that happen in the botropic accidents. The mechanisms involved in the local actions of this venom are little known. This study has as objective investigates the morphologic and inflammatory local actions of the venom of Philodryas patagoniensis and the mechanisms involved in the development of the pain and edema, through pharmacological modulation. The protein content of the venom was of 70-75%. The eletrophoretic analysis (SDS-PAGE 7,5-17,5%) it presented bands of protein with molecular weights between 62 and 14 kDa, being four majority in 62, 48, 35 and 30 kDa. The edema measured by pletismography, it was maximum 30 min after the inoculation (53,33 ± 1,43%), regressing starting from at 6th hour, it was shown dose-dependent, the edematogenic minimum dose was of 0,82µg and it was inhibited in 45% by EDTA. The nociceptive activity was evaluated by the time (in seconds) in that the animals licked or they bit the injected paw, and the results showed that such activity is dose-dependent, being significantly different from the control and independent of metaloproteinases, once it was not inhibited by EDTA. Through the pharmacological modulation it was possible to observe that the pain caused by the venom was inhibited by Indometacin, Cyproheptadine and Tramal, being mediated by opioids, prostaglandins and serotonin. It was potentiated by Captopril, suggesting the possible participation of kinins, as well as for L-NAME (10mg/kg). Dexamethasone, Prometazine, Arcoxia, Celebra and L-NAME (50mg/kg) didn\'t interfere in this activity. The edema was inhibited by Dexamethasone and Indometacin and, therefore, mediated for prostaglandins and leukotrienos. Captopril, Tramal, Prometazine, L-NAME, Arcoxia and Celebra were not capable to interfere significantly in the edema. The intramuscular injection of 30µg of the venom produced effects as disorganization of the muscular fibrils, hemorrhage, edema, inflammatory infiltrated and mionecrosis of the coagulative and miolitic types, which were inhibited in the presence of PMSF and 1-10Phenantrolina. Three, six and 24 hours after the intra-muscular inoculation of 60µg of venom, happened a gradual decrease of proteins no-colagen with light reduction in some miofibrilar components observed by SDS-PAGE (17,5%). The inflammatory infiltrated induced in cavity peritoneal was maximum three hours after the injection and the differential cellular counting presented polimorfonuclear leukocytes predominantly. The technique of intravital microscopy direct demonstrated that the topical administration of venom 0,1µg induced outstanding disturbances in post-capillary venules, characterized by vasodilatation, hemorrhagic lesions distributed in focuses (microbleedings) and alterations in the interactions leukocyte-endothelium, such as reduction of the number of leukocytes in rolling, increase of the adhesion and induction of the migration of cells through the wall of the endothelium. The subcutaneous inoculation of the venom in the scrotal bag of mice induced typical effects of sharp inflammation, with migrated leukocytes seen starting from one hour after the inoculation, regressing in 48 hours. The venom acts on mast cells in vitro, causing degranulating and consequent liberation of histamine concentration-dependent. The results obtained indicate the inflammatory potential of this venom and the kinetics of the events suggests a complex synergy of several effects, contributing to the severity of the local picture in the envenomings.

Foram caracterizadas e comparadas a morfologia, a dieta, a utilização do substrato, a atividade sazonal e a biologia reprodutiva de Tropidodryas serra e T. striaticeps ao longo de toda sua distribuição na Mata Atlântica. Há segregação altitudinal na maior parte da distribuição geográfica das duas espécies-irmãs, T. serra habita predominantemente áreas de baixada e T. striaticeps ocupa as porções mais elevadas. Em localidades onde ocorrem em simpatria, há diferenciações na morfologia, na utilização do hábitat, nos tipos de presas consumidas e na extensão dos ciclos reprodutivos, possibilitando a partilha de recursos entre as duas espécies afins. As fêmeas das duas espécies foram maiores que os machos, indicando que não há combate ritual. Os machos em ambas as espécies apresentaram maiores comprimentos relativos da cauda, da cabeça e do olho que as fêmeas conspecíficas. Nas duas espécies as fêmeas foram mais robustas que os machos. Com relação às diferenças interespecíficas, T. serra é maior e mais pesada e T. striaticeps tem cauda, cabeça e olhos maiores. Nas duas espécies, os juvenis apresentaram a ponta da cauda branca. Os adultos de T. serra alteraram a coloração da ponta da cauda com a mudança nos tipos de presas ingeridas, ao passo que os adultos de T. striaticeps mantiveram a ponta da cauda branca mesmo com a variação na dieta. Poucos foram os indivíduos, em ambas as espécies, com mutilações na ponta da cauda. As duas espécies são diurnas, procuram ativamente por suas presas no solo e sobre a vegetação. Parecem utilizar mais a vegetação para repousar. Tropidodryas serra utiliza a vegetação com maior freqüência que T. striaticeps. Alimentam-se principalmente de mamíferos, mas incluem também aves, lagartos, anuros e serpentes na sua dieta. Tropidodryas serra apresentou maior equitabilidade na freqüência de captura de diferentes itens alimentares. Tropidodryas striaticeps apresentou maior freqüência de indivíduos com alimento no trato digestivo. Há variação ontogenética na dieta: juvenis se alimentam de presas ectotérmicas e adultos, em sua maioria, de endotérmicas. As fêmeas de T. serra foram coletadas com mais freqüência durante os meses mais quentes e chuvosos e os machos tiveram um pico de atividade entre fevereiro e abril. Os machos e as fêmeas de T. striaticeps não apresentaram diferenças na abundância ao longo do ano. Em T. serra as fêmeas atingiram a maturidade sexual antes que os machos coespecíficos, já em T. striaticeps ocorreu o contrário, os machos maturaram antes que as fêmeas. As fêmeas das duas espécies apresentam ciclos sazonais, com vitelogênese secundária e ovos durante a estação chuvosa. Nas fêmeas de T. serra o ciclo reprodutivo é mais restrito, as ninhadas são menores, os recém-nascidos maiores e a freqüência reprodutiva é maior que nas fêmeas de T. striaticeps. O ciclo espermatogênico é contínuo em ambas as espécies. O volume dos testículos e o diâmetro dos ductos deferentes se mantiveram elevados durante todo o ano nas duas espécies congêneres. Portanto, o ciclo sazonal nas fêmeas é pós-nupcial (a produção de ovos é dissociada da época de cópula) e o ciclo contínuo nos machos é pré-nupcial (a cópula ocorre simultaneamente com a produção de espermatozóides). / Morphology, diet, habitat use, seasonal activity and reproductive biology were analyzed and compared between Tropidodryas serra and T. striaticeps along their geographical distribution in the Atlantic Forest. The distribution of these sister species do not overlap in most of their range, T. serra have its distribution in lower altitude areas\' while T. striaticeps occurs in higher ones. In some localities where both species occur in sympatry they develop differences in body size, habitat preferences, food items and extension of reproductive cycles allowing them to share the resources. Mature females attained larger body sizes than mature males in T. striaticeps and T. serra, such differences in body length suggest that the ritual combat is absent. Males attained larger lengths of tail, head and eye than did females. In both species females have stouter body than males. Interespecific comparison shows that T. serra has the largest body size and is stouter whereas T. striaticeps has the largest tail, head and eye and is more slender. The juveniles present the tip of the tail white. Tail tip of adults T. serra is suffused with cryptic colors but in T. striaticeps the whitish tail tip remains until adult stage although the ontogenetic dietary changes take place. There were few individuals with tail injures. Both species are diurnal and forage actively on the ground and upon the vegetation. They may use the vegetation to rest. Tropidodryas serra seems to inhabit more frequently the lower branches of the vegetation instead T. striaticeps may use the canopy trees. They feed mainly on mammals, but also prey birds, lizards, anurans and snakes. Tropidodryas serra has a more equitable frequency of capture of food items whereas T. striaticeps shows a higher frequency of individuals with preys in their gut. The ontogenetic shift in diet is present, juveniles prey upon ectothermics and adults feed on endothermic preys. Females of T. serra show a peak of abundance during the warmest and rainy periods of the year and males show a peak of activity in February and April. Both sexes in T. striaticeps were equally distributed among seasons, showing no differences between rainy and dry one. Females attained sexual maturity before males in T. serra, the converse occur to T. striaticeps where males where mature before the co-specific females. Both females of these two closely related species present seasonal reproductive cycles with vitellogenesis and egg-laying occurring at the rainy season. In T. serra females the reproductive cycle is more restrict, the clutch size is smaller, the newborns are bigger and the frequency of reproduction higher than T. striaticeps. The spermatogenic cycle is continuous, testes volume and deferent ducts diameter did not vary throughout the year for both species. The seasonal cycle in females is postnuptial (mating seems to be dissociated from vitellogenesis and egg production) and the continuous cycle in males is prenuptial (the produced sperm is used immediately during the mating).

Orientador: Marcos Roberto de Mattos Fontes / Banca: Richard Garratt / Banca: Jonas Perales / Banca: Humberto D'Muniz / Banca: Marcia Gallaci / Resumo: O envenenamento por picadas de serpentes é um importante problema de saúde pública em muitos países tropicais e subtropicais. Aspectos científicos, médicos e sociais relacionados ao envenenamento por serpentes do gênero Bothrops são especialmente importantes no Brasil já que estes animais são responsáveis por aproximadamente 90% dos acidentes ofídicos relatados em nosso país. Um dos principais problemas relacionados ao acidente botrópico é o proeminente dano tecidual local cuja patogênese é complexa e envolve a ação combinada de uma variedade de componentes do veneno. As fosfolipases A2 (PLA2s) são os componentes mais abundantes no veneno e tem papel fundamental quando se trata do estabelecimento de lesão muscular. O presente trabalho descreve estudos estruturais com miotoxinas que adotam enovelamento de PLA2s (PLA2s homólogas) com o objetivo de melhor entender a relação estrutura - função destas toxinas. Para tanto, estudos estruturais por cristalografia de difração de raios X com Lys49-PLA2s de venenos botrópicos complexadas com os inibidores manganês e ácido rosmarínico (AR) foram realizados. A estrutura cristalográfica de uma miotoxina Asp49-PLA2 homóloga complexada com cálcio também foi elucidada. Adicionalmente, o arranjo quaternário de miotoxinas Asp49-PLA2s homólogas do gênero Bothrops foi revisado e características estruturais relevantes para a expressão da miotoxicidade destas proteínas foram apontadas. A estrutura cristalográfica do complexo formado entre uma Lys49-PLA2 e o inibidor AR evidencia que este inibidor interage com a proteína na entrada de uma dos canais hidrofóbicos do dímero protéico, estabelecendo ligações de hidrogênio com átomos dos resíduos Phe3, Lys7, Leu10, Gln11 e Gly15 do monômero com a qual interage. Já no... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Envenoming resulting from snakebites is an important public health problem in many tropical and subtropical countries. Scientific, medical and social aspects related to envenoming by snakes from Bothrops genus are especially important in Brazil because these animals are responsible for approximately 90 % of all ophidian accidents reported in our country. One of the main problems regarding bothropic accidents is a prominent local tissue damage whose pathogenesis is complex and involves the combined action of a variety of venom components. Phospholipases A2 (PLA2s) are the most abundant muscle-damaging components of these venoms playing a central role in the muscle damage establishment. The present work reports structural studies with myotoxins that adopt a PLA2 fold (PLA2- like myotoxins) aiming a better understanding of their structure-function relationship. For this purpose, X-ray crystallographic studies of Lys49-PLA2s from bothropic snake venoms complexed to the inhibitors manganese and rosmarinic acid (RA) were performed. The crystallographic structure of the complex formed between an Asp49-PLA2-like myotoxin and calcium was also solved. Additionally, the quaternary assembly of Asp49-PLA2-like myotoxins from Bothrops genus was reviewed and relevant structural features for their myotoxicity expression were pointed out. The crystallographic structure of the complex formed between a Lys49-PLA2 and the inhibitor RA demonstrates that the inhibitor interacts with the protein in the entrance of one of its hydrophobic channel, establishing hydrogen bonds with atoms of the residues Phe3, Lys7, Leu10, Gln11 and Gly15 of the monomer with which it interacts. For the complex formed between a Lys49-PLA2 and the inhibitor Mn2+ the manganese ion is coordinated by atoms of the... (Complete abstract click electronic access below) / Doutor

Orientador: Márcia Gallacci / Banca: Selma Maria Michelin Matheus / Banca: Yoko Yoshima-Franco / Resumo: Os acidentes botrópicos representam cerca de 87% dos envenenamentos ofídicos registrados no Brasil e se destacam pelas graves seqüelas que limitam a vida do acidentado. O principal efeito tóxico local destes é a mionecrose, que pode levar à perda tecidual permanente e à amputação. A mionecrose pode ser decorrente da isquemia do tecido muscular, causada por fatores hemorrágicos presentes nestes venenos (metaloproteases), ou da presença de miotoxinas (PLA2s) que afetam diretamente o tecido muscular. O método mais eficaz para o tratamento dos envenenamentos ofídicos é a soroterapia passiva. No entanto, esta é limitada devido à relativa ineficácia do soro em neutralizar a mionecrose dos venenos botrópicos, além de muitas comunidades não terem acesso à soroterapia. Estes fatores conduzem a busca de métodos alternativos, como o uso de extratos vegetais. Evidências mostram que o extrato aquoso da Casearia sylvestris, conhecida popularmente como "guaçatonga, é capaz de neutralizar efeitos tóxicos de venenos brutos e de suas miotoxinas isoladas. A Casearia sylvestris apresenta diversos outros efeitos terapêuticos como: anti-séptico, antiinflamatório, anestésico local, anti-tumoral, anti-úlcera e cicatrizante. Devido à escassez de estudos experimentais para avaliar a eficácia de extratos vegetais na redução dos danos locais ocasionados pelo envenenamento botrópico, torna-se importante avaliar a potencial atividade antiofídica da Casearia sylvestris. O presente estudo teve por objetivo investigar o uso do extrato aquoso da Casearia sylvestris, como terapêutica tópica dos efeitos locais do envenenamento botrópico experimental em camundongos. Foi avaliada a capacidade do extrato bruto da planta em neutralizar a mionecrose induzida pelo veneno da Bothrops jararacussu e/ou acelerar o processo de regeneração... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Bothrops accidents represent about 87% of snakebites recorded in Brazil and account for serious the consequences that affect the life of the victim with social and economic repercussions. Its main toxic effect is myonecrosis, which can lead to permanent tissue loss and amputation. Myonecrosis may result from muscle tissue ischemia, hemorrhage caused by factors present in these venoms (metalloproteases), or the presence of myotoxins (PLA2s) that directly affect muscle tissue. The most effective treatment is passive serotherapy. However, this is limited due the relative ineffectiveness of the serum to neutralize the myonecrosis of Bothrops venoms and the lack of access to serotherapy by many communities. These factors lead to alternative methods such as the use of plant extracts. Evidence shows that the aqueous extract of Casearia sylvestris, known popularly as "guaçatonga", is able to neutralize the toxic effects of venom and their crude myotoxins isolated. Casearia sylvestris presents several other therapeutic effects such as, antiseptic, antiinflammatory, local anesthetic, anti-tumor, anti-ulcer and wound healing. Due to the scarcity of experimental studies to evaluate the efficacy of plant extracts in reducing the harm caused by Bothrops envenomation, it is important to evaluate the potential activity of antiophidic Casearia sylvestris as a complement to conventional serum therapy. The present study aimed to investigate the use of aqueous extract of Casearia sylvestris, topical therapy as complementary to local effects of Bothrops envenomation in experimental mice. We evaluated the ability of the crude extract of the plant to neutralize myonecrosis induced by the venom of Bothrops jararacussu and / or accelerate the process of muscle regeneration. The onset of myonecrosis and the regenerative process... (Complete abstract click electronic access below) / Mestre

Many plants and animals are defended by toxic compounds, and circumvention of those defenses often has involved the evolution of elaborate mechanisms for tolerance or resistance of the toxins. Toads synthesize potent cardiotonic steroids known as bufadienolides (BDs) from cholesterol and store those toxins in high concentrations in their cutaneous glands. Those toxins protect toads from the majority of predators, including most snakes that readily consume other species of frogs. BDs exert their effect by inhibiting ion transport by the Na+/K+-ATPase (NKA). This ubiquitous transmembrane enzyme consists of a catalytic alpha-subunit, which carries out the enzyme's functions, and a glycoprotein beta-subunit, which provides structural stability. Inhibition of the NKA causes highly elevated intracellular Ca2+ levels and results in often lethal increased cardiac contraction strength. Molecular resistance to bufadienolides in snakes is conferred by mutations in the alpha-subunit of the Na+/K+-ATPase. I have found that these mutations are more prevalent in snakes than previously suggested, and that many genetically resistant species do not feed on toads. This suggests that possession of the mutations alone does not carry substantial negative consequences, and that feeding on toads may have been an ancestral habit in some groups of snakes. I have further found evidence of tissue-specific variation in resistance to bufadienolides, and gene expression investigations revealed that the bufadienolide resistance-conferring mutations are not expressed equally among different organs. Variation in resistance among different tissues indicates that possession of the mutations does not protect all cells equally. Finally, by testing the physiological responses of resistant snakes to exposure to cardiotonic steroid, I have found that feeding on toads incurs negative consequences and that toad-specialized resistant snakes respond differently from nontoad-specialized resistant snakes. The presence of physiological consequences of toxin exposure may explain why feeding on toads has been lost in some lineages of snakes that retain resistance-conferring mutations. In summary, these findings indicate that genetic resistance of the Na+/K+-ATPase is necessary in order for snakes to survive acute toxicity of bufadienolides, but it is not sufficient to explain fully the physiological mechanisms involved in dealing with chronic exposure to the toxins.

We introduce a new way to accurately segment the 3D femur from pelvic CT scans. The femur is a difficult target for segmentation due to its proximity to the acetabulum, irregular shape and the varying thickness of its hardened outer shell. Atypical bone morphologies, such as the ones present in hips suffering from Femoral Acetabular Impingements (FAIs) can also provide additional challenges to segmentation. We overcome these difficulties by (a) dividing the femur into the femur head and body regions (b) analysis of the femur-head and neighbouring acetabulum’s composition (c) segmentations with two levels of detail – rough and fine contours. Segmentations of the CT volume are performed iteratively, on a slice-by-slice basis and contours are extracted using the morphological snake algorithm. Our methodology was designed to require little initialization from the user and to deftly handle the large variation in femur shapes, most notably from deformations attributed to cam-type FAIs. Our efforts are to provide physicians with a new tool that creates patient-specific and high-quality 3D femur models while requiring much less time and effort. We tested our methodology on a database of 20 CT volumes acquired at the Ottawa General Hospital during a study into FAIs. We selected 6 CT scans from the database, for a total of 12 femurs, considering wide inter-patient variations. Of the 6 patients, 4 had unilateral cam-type FAIs, 1 had a bilateral cam-type FAI and the last was from a control group. The femurs segmented with our method achieved an average volume overlap error of 2.71 ± 0.44% and an average symmetric surface distance of 0.28 ± 0.04 mm compared against the same, manually segmented femurs. These results are better than all comparable literature and accurate enough to be used to in the creation of patient-specific 3D models.

Habitat loss is the greatest contributor to the decline of species globally and thus understanding habitat use and the consequences fragmentation has on biodiversity is a fundamental step towards management and recovery. I conducted a radio-telemetry study to examine the spatial ecology and the effects of roads on Eastern Hognose Snakes (Heterodon platirhinos), a species at risk, in the Long Point Region of Ontario, Canada. I tested habitat selection at multiple spatial scales and I found that within the home range, snakes avoided agricultural land and selected open sand barrens, particularly for nesting. At the local scale, snakes avoided mature overstory trees and used younger patches of forest. Used locations had more woody debris, logs and low-vegetative coverage than locations selected at random. Eastern Hognose Snakes also showed avoidance of paved road crossings in their seasonal movements, but readily crossed unpaved roads. Management efforts for this species at risk should be placed on the conservation of sand barrens and on the construction of road underpasses to prevent genetic isolation of populations.

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We introduce a new way to accurately segment the 3D femur from pelvic CT scans. The femur is a difficult target for segmentation due to its proximity to the acetabulum, irregular shape and the varying thickness of its hardened outer shell. Atypical bone morphologies, such as the ones present in hips suffering from Femoral Acetabular Impingements (FAIs) can also provide additional challenges to segmentation. We overcome these difficulties by (a) dividing the femur into the femur head and body regions (b) analysis of the femur-head and neighbouring acetabulum’s composition (c) segmentations with two levels of detail – rough and fine contours. Segmentations of the CT volume are performed iteratively, on a slice-by-slice basis and contours are extracted using the morphological snake algorithm. Our methodology was designed to require little initialization from the user and to deftly handle the large variation in femur shapes, most notably from deformations attributed to cam-type FAIs. Our efforts are to provide physicians with a new tool that creates patient-specific and high-quality 3D femur models while requiring much less time and effort. We tested our methodology on a database of 20 CT volumes acquired at the Ottawa General Hospital during a study into FAIs. We selected 6 CT scans from the database, for a total of 12 femurs, considering wide inter-patient variations. Of the 6 patients, 4 had unilateral cam-type FAIs, 1 had a bilateral cam-type FAI and the last was from a control group. The femurs segmented with our method achieved an average volume overlap error of 2.71 ± 0.44% and an average symmetric surface distance of 0.28 ± 0.04 mm compared against the same, manually segmented femurs. These results are better than all comparable literature and accurate enough to be used to in the creation of patient-specific 3D models.