Blood from the glandular part of hamster gastric mucosa is drained by collecting venules, running from the subepithelial layer towards lamina muscularis mucosae. To visualise vessels involved in the venous outflow, hamsters were exposed to atropine and subjected to intravital ligation of portal vein, causing strong hyperaemia. Distribution of vessels and their connections were studied a) in translucent, flat preparations of the glandular stomach, b) in thick sections of glandular mucosa cleared in the mineral oil, and c) in semi-thin plastic or paraffin sections. Collecting venules were drained by single vessels running parallel to the lamina muscularis mucosae (paramuscular venules), which, in turn, joined submucosal veins through openings in muscularis mucosae. Moreover, some collecting and paramuscular venules discharged into venules belonging to vascular triples composed of two venules and arteriole. The triplets were also parallel to muscularis mucosae. Triplets did not form connections with submucosal veins but passed on the abluminal surface of muscularis mucosae. Thus, some structural elements involved in venous outflow from glandular gastric mucosa differ from those in rats, in which vascular triplets were absent and all collecting venules drained into single paramuscular vessels. Contraction/relaxation of muscularis mucosae may regulate the amount of blood present in the venous system of the mucosa and the diameter of venules. Rhythmical changes of the latter could cause changes in intramucosal pressure, affecting movement of tissue fluid in the mucosa and thus the function of gastric cells.
Chondrocytes differentiate from mesenchymal progenitors and produce templates (anlagen) for the developing bones. Chondrocyte differentiation is controlled by Sox transcription factors. Templates for the neighbour bones are subsequently separated by conversion of differentiated chondrocytes into non-chondrogenic cells and emergence of interzone in which joints cavitation occurs. A central role in initiating synovial joint formation plays Wnt-14/beta-catenin signalling pathway. Moreover, bone morphogenetic proteins and growth and differentiation factors are expressed at the site of joint formation. Joint cavitation is associated with increased hyaluronic acid synthesis. Hyaluronic acid facilitates tissue separation and creation of a functional joint cavity. According to the traditional view articular cartilage represents part of cartilage anlage that is not replaced by bone through endochondral ossification. Recent studies indicate, however, that peri-joint mesenchymal cells take part in interzone formation and that these interzone cells subsequently differentiate into articular chondrocytes and synovial cells. Thus, anlage chondrocytes have a transient character and disappear after cessation of growth plate function while articular chondrocytes have stable and permanent phenotype and function throughout life. (Folia Morphol 2013; 72, 3: 181–187)
Synovial membrane is traditionally considered as a part of the joint capsule. It, however, differs from fibrous part of the capsule in development, structure, function, vascularisation, innervation and involvement in pathological processes. Moreover, in some areas, it even does not contact with the fibrous capsule. Thus, it appears that the synovial membrane should be considered as an independent organ and not as the lining of the joint capsule. (Folia Morphol 2014; 73, 4: 395–398)
Potencjał właściwości drażniących substancji chemicznych jest obecnie oceniany zdolnością do wywoływania podrażnienia oka królika (test Draize'a). Ze względów humanitarnych zaleca się zastąpienie tego testu testami alternatywnymi. Niniejszy artykuł jest przeglądem testów alternatywnych do testu Draize'a, wykonywanych w laboratoriach krajów Wspólnoty Europejskiej, jednocześnie jest dyskutowana czułość metod oraz ich powtarzalność.
The eye irritancy test in rabbits (Draize test) is currently the method used to evaluate the hazard or safety of chemical substances. To reduce the need for animal testing some new procedures as alternative were elaborated. We present a review of method used as well as evaluation of sensitivity and repeatability of alternative tests applied in laboratories of European Economic Communities.
The purpose of this work was to compare the organisation of the gastric mucosal venous system in larger animals, exemplified by rabbits, with that of the rat and the hamster which we have described previously. Rabbits were given atropine and hexamethonium followed by intravital ligation of all veins draining the stomach, causing strong hyperaemia. The distribution of vessels was studied in the non-mounted mucosa, in mounts of mucosa cleared in light mineral oil and in paraffin or semi-thin plastic sections. We found that blood from rabbit gastric mucosa is drained by collecting venules, running from the subepithelial layer towards the muscularis mucosae. The collecting venules join the paramuscular vessels parallel and adjacent to the muscularis mucosae. Neighbouring venules form numerous arcade-like connections and gradually enlarge. Two venules and an arteriole form triplets initially situated at the luminal face of the muscularis mucosae and gradually passing onto its abluminal surface. In rats vascular triplets were absent and the collecting venules drained into paramuscular vessels joining submucosal veins. In hamsters both connections between paramuscular vessels and submucosal veins and the passing of vascular triplets across muscularis mucosae were observed. Contraction/relaxation of the muscularis mucosae may regulate the amount of blood in the venous system of the mucosa and change the intramucosal pressure, affecting movement of the tissue fluid and, indirectly, the function of the gastric cells.