1,721,059 research outputs found
Gametogenesis and maturity stages scale of Raja asterias Delaroche, 1809 (Chondrichthyes, Raijdae) from the South Ligurian Sea
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Immunohistochemical Study on Glucagon-Like Peptide-1(GLP-1) and Pituitary Adenylate Cyclase Activating Peptide (PACAP) in the Small Intestine of Muscovy Duck during the Prehatching and Posthatching Periods
No full textImmunohistochemical Localization of Glucagon-Like-Peptide 1 in the Canine Embryo
No full textGLP-1 is a peptide hormone highly conserved among mammals that derives from a tissue specific post-translational processing of the proglucagon gene. It is known to be produced in the intestinal L-cells as a consequence of pro-hormone convertase PC 1/3 cleavage of major proglucagon fragment. It has a role as “incretin” stimulating postprandial insulin synthesis and secretion, somatostatin release and inhibiting glucagon secretion. Recently a role has been assigned in embryological processes and in the differentiation of the pancreatic β-cells. Objective. The aim of this study was to describe GLP-1 distribution in the canine embryo. Methods. Paraffin sections obtained from 6 thirtydays canine embryos collected from two different mothers during hysterectomy were used in the present study. Immunolocalization of GLP-1 and Chromogranin-A was performed by using the peroxidase method. Colocalization studies were also accomplished by immunofluorescence. Results. We detected GLP-1 only in the developing primordial of pancreas where it did colocalize sometimes with Chromogranin-A. Intestinal presence of GLP-1 was not detected. Chromogranin-A was very seldom observed in the developing duodenum. Conclusions. Our results suggest an embryologic role of GLP-1 in pancreas organogenesis. This speculation is further corroborated by the recent literature data on the potential role of the α-cells in stimulating either the generation (embryos) or the re-generation of β-cells together with the GLP-1 ability to modulate different pathways involved in tissue morphogenesis and differentiation
Bioinspired liver scaffold design criteria
No full textMaintaining hepatic functional characteristics in-vitro is considered one of the main challenges in engineering liver tissue. As hepatocytes cultured ex-vivo are deprived of their native extracellular matrix (ECM) milieu, developing scaffolds that mimic the biomechanical and physicochemical properties of the native ECM is thought to be a promising approach for successful tissue engineering and regenerative medicine applications. On the basis that the decellularized liver matrix represents the ideal design template for engineering bioinspired hepatic scaffolds, to derive quantitative descriptors of liver ECM architecture, we characterised decellularised liver matrices in terms of their biochemical, viscoelastic and structural features along with porosity, permeability and wettability. Together, these data provide a unique set of quantitative design criteria which can be used to generate guidelines for fabricating biomaterial scaffolds for liver tissue engineering. As proof-of-concept, we investigated hepatic cell response to substrate viscoelasticity. On collagen hydrogels mimicking decellularised liver mechanics, cells showed superior morphology, higher viability and albumin secretion than on stiffer and less viscous substrates. Although scaffold properties are generally inspired by those of native tissues, our results indicate significant differences between the mechano-structural characteristics of untreated and decellularised hepatic tissue. Therefore, we suggest that design rules - such as mechanical properties and swelling behaviour - for engineering biomimetic scaffolds be re-examined through further studies on substrates matching the features of decellularized liver matrices
Parvalbumin expression in the claustrum of the adult dog. An immunohistochemical and topographical study with comparative notes on the structure of the nucleus
Full text linkAlthough the detailed structure and function of the claustrum remain enigmatic, its extensive reciprocal connection with the cortex suggests a role in the integration of multisensory information.
Claustrum samples, obtained from necropsy of four dogs, were formalin fixed for paraffin embedding. Sections were either stained for morpho-histological analysis or immunostained for parvalbumin (PV). We focused on PV because in cortical and hippocampal areas it is a marker of the fast-splicing interneurons which have an important role in the information transmission and processing. Soma area, perimeter and circularity were considered as morphological parameters to quantitatively group the PV positive somata by k-means clustering.
The histological investigation revealed a superior pyramidoid puddle and a posterior puddle characterized by a "cloud" of neurons in its dorso-lateral part. Immunostaining showed positive somata and fibers throughout the rostro-caudal extent of the dog claustrum, localized principally in the dorsal region. k-Means clustering analysis enabled neuron classification according to size, identifying respectively big (radius = 11.42 +/- 1.99 mu m) and small (radius = 6.33 +/- 1.08 mu m) cells. No statistical differences in soma shape were observed. The topographical distribution of PV immunoreactivity suggests that the dog dorsal claustrum might be functionally related to the processing of visual inputs.
Taken together our findings may help in the understanding the physiology of claustrum when compared with anatomical and functional data obtained in other species
Localization of the Ca2+-binding proteins, cannabinoid CB1 receptor (CB1R) and fatty acid amide hydrolase (FAAH) in the swine claustrum
No full textIntroduction: Elevation of intracellular Ca2+ is associated to the retrograde suppression of the synaptic transmission mediated by cannabinoid CB1R. Also, in cultured trigeminal ganglion neurons, the endocannabinoid anandamide directly caused Ca2+ influx in a dose-dependent manner, which then triggered an increase of intracellular Ca2+ concentration. Moreover, the endocannabinoid anandamide degrading enzyme FAAH is a postsynaptic enzyme associated with membranes organelles known to store Ca2+ (e.g. mitochondria, smooth endoplasmic reticulum) localized in somata and dendrites. Thus we investigated here the immunohistochemical localization of CB1 receptor, FAAH and the Ca2+-binding proteins Parvalbumin (PV), Calbindin (CB) and Calretinin (CR) in the pig claustrum.
Materials and Methods: Claustrum samples, obtained from four healthy slaughtered animals (females, 10 months old), were promptly formalin fixed for paraffin embedding. Commercially available antibodies were used to reveal CB1R, FAAH, PV, CB and CR presence by mean of indirect immunohistochemistry using the anti-peroxidase method.
Results: Immunoreactive somata and nerve fibers were recorded for PV, CR and CB throughout the pig claustrum. The CB1R antibody labeled nerve fibers, whereas the anti-FAAH antibody stained cell bodies. All the structures identified in the stained sections revealed that FAAH-immunoreactive (ir) neuronal somata and dendrites were surrounded by CB1R-ir fibers.
Conclusion: CB1R and FAAH complementary immunostaining and their cellular localization reported here provide the first anatomical evidence for existence of the endocannabinoid system in the swine claustrum. The observed populations of Ca2+-binding proteins positive interneurons lead to the hypothesis that the endocannabinoid system could play a role in the so-called depolarization-
induced suppression of inhibition. Further investigations including colocalization studies may help clarifying how interneurons are involved in the claustrum endocannabinoid system of pigs
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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