Browsing by Issue Date, starting with "2024-04-18"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Spatio-temporal dynamics of early somite segmentation in the chicken embryoPublication . Maia-Fernandes, Ana C; Martins, Ana; Borralho Martins, Nísia; Pais de Azevedo, Tomás; Magno, Ramiro; dos Santos Duarte, Guilhermina Isabel; Andrade, Raquel; MDuring vertebrate embryo development, the body is progressively segmented along the anterior-posterior (A-P) axis early in development. The rate of somite formation is controlled by the somitogenesis embryo clock (EC), which was first described as gene expression oscillations of hairy1 (hes4) in the presomitic mesoderm of chick embryos with 15-20 somites. Here, the EC displays the same periodicity as somite formation, 90 min, whereas the posterior-most somites (44-52) only arise every 150 minutes, matched by a corresponding slower pace of the EC. Evidence suggests that the rostral-most somites are formed faster, however, their periodicity and the EC expression dynamics in these early stages are unknown. In this study, we used time-lapse imaging of chicken embryos from primitive streak to somitogenesis stages with high temporal resolution (3-minute intervals). We measured the length between the anterior-most and the last formed somitic clefts in each captured frame and developed a simple algorithm to automatically infer both the length and time of formation of each somite. We found that the occipital somites (up to somite 5) form at an average rate of 75 minutes, while somites 6 onwards are formed approximately every 90 minutes. We also assessed the expression dynamics of hairy1 using half-embryo explants cultured for different periods of time. This showed that EC hairy1 expression is highly dynamic prior to somitogenesis and assumes a clear oscillatory behaviour as the first somites are formed. Importantly, using ex ovo culture and live-imaging techniques, we showed that the hairy1 expression pattern recapitulates with the formation of each new pair of somites, indicating that somite segmentation is coupled with EC oscillations since the onset of somitogenesis.
- Epidemiological and clinical aspects of Cutaneous and Mucosal Leishmaniases in Portugal: retrospective analysis of cases diagnosed in public hospitals and reported in the literature between 2010 and 2020Publication . Rocha, Rafael; Conceição, Cláudia; Gonçalves, Luzia; Carvalho, Ana Cláudia; Maia, André; Martins, André; Carujo, António; Maio, António; Forra, Catarina; Melita, Catarina; Couto, Daniela; Fernandes, Diana; Pereira, Dulce; Leal, Ema; Sarmento, Helena; Sousa, Inês; Gonçalves, Jean-Pierre; Marinho, Joana; Vasconcelos, Joana; Cunha, João; Rodrigues, João; Silva, José Miguel; Caley, Lídia; Malheiro, Luís; Santos, Luís; Garcia, Margarida; Cunha, Maria; Lima, Maria; Andrade, Maria Margarida; Marques, Marta; Alpalhão, Miguel; Silva, Mónica; Ferraz, Rita; Soares, Rui; Fernandes, Salomão; Llobet, Samuel; Cruz, Sofia; Guimarães, Teresa; Branco, Tiago; Nunes, Tomás Robalo; Almeida, Vasco; Maia, CarlaLeishmania infantum, a zoonotic vector-born parasite, is endemic in the Mediterranean region, presenting mostly as visceral (VL), but also as cutaneous (CL) and mucosal leishmaniasis (ML). This study aimed to describe the epidemiological and clinical aspects of the CL and ML cases diagnosed in mainland Portugal between 2010 and 2020. Collaboration was requested from every hospital of the Portuguese National Health System. Cases were screened through a search of diagnostic discharge codes or positive laboratory results for Leishmania infection. Simultaneously, a comprehensive literature search was performed. Descriptive statistics and hypothesis testing were performed using IBM (R) SPSS (R) Statistics. A total of 43 CL and 7 ML cases were identified, with a predominance of autochthonous cases (86%). In CL, immunosuppressed individuals constituted a significant proportion of patients (48%), and in this group, disseminated CL (22%) and simultaneous VL (54%) were common. In autochthonous cases, lesions, mostly papules/nodules (62%), were frequently observed on the head (48%). The approach to treatment was very heterogeneous. ML cases were all autochthonous, were diagnosed primarily in older immunosuppressed individuals, and were generally treated with liposomal amphotericin B. The findings suggest a need for enhanced surveillance and reporting, clinical awareness, and diagnostic capacity of these forms of leishmaniasis to mitigate underdiagnosis and improve patient outcomes. A holistic One Health approach is advocated to address the multifaceted challenges posed by leishmaniases in Portugal and beyond.