M. Correia

Morphology of the Veins Draining the Coronary Sinus of the Dog

The morphology of the superficial cardiac veins draining the coronary sinus was investigated in 47 normal adult dogs, using the injection-corrosion-fluorescence technique. The veins pertaining to the left coronary territory all drain directly to the coronary sinus and include the following vessels: the great coronary vein and its tributaries, the left posterior atrial and ventricular veins. The veins pertaining to the right coronary territory include the posterior interventricular vein and the small cardiac vein. A comparison with the human pattern was made, particularly regarding the number of interventricular septal branches and it was suggested that such a reduction in number in the dog could be due to a take-over from the Thebesian veins in the venous drainage of the interventricular septum.

Immunophenotyping of Lymphocyte Subsets in the Third Eyelid Tissue in Dogs (Canis familiaris): Morphological, Microvascular, and Secretory Aspects of This Ocular Adnexa

The third eyelid is an important adnexa of the eye. The objective of this study was to evaluate (i) morphological aspects (ii) vascularization, and (iii) the immunophenotype of lymphocyte subsets in the third eyelid of dogs. Flow cytometric analysis revealed the presence of three patterns concerning the immunophenotype of the third eyelid tissue. Dogs without ocular insult or deficient tear production might belong to one of the following immunophenotype patterns: I ‐ the number of T‐cells that expressed CD3+ CD8+ was higher than the number of cells that expressed CD3+CD4+. II ‐ the number of cells CD3+C4+ was higher than the number of cells CD3+CD8+ and in this case a higher number of cells that expressed CD19 were identified. III ‐ Proximity of values of the cells that expressed CD3+CD4+ and CD3+CD8+. These data might suggest that the number of lymphocyte T cells alone should not be considered a direct indicator of the presence of an immune‐based inflammation. Besides, a particular population of T‐cells does not indicate a particular inflammatory state. The morphological study of the third eyelid revealed a rather uncommon angioarchitecture. The artery that irrigates the eyelid crosses almost the entire length of this structure to achieve its free border, and only then, ramificates deeply towards an inner segmental level. This spatial microvascular arrangement probably results from an adaptation to the fact that the third eyelid, in the medial cantus of the eye, is inwardly compressed into a tiny space. Efficient vascularization is achieved by allowing the first ramifications of the third eyelid artery to run straight to the top. Accini secretor cells of the third eyelid show a mucin content while tubuloacinar cells are mainly serous. Microsc. Res. Tech., 2008.

Microvascularization of the Third Eyelid in Dogs

The third eyelid protects the eye, contribute to the aqueous portion of the pre-ocular film and its distribution over the corneal surface, as well as removal of foreign material from the anterior surface of the eye. It is rather vulnerable during fights and clinicians often have to perform surgery for third eyelid neoplasia. In dogs, this lid has a triangular shape, being widest at its free margin. It is vascularized by branches of the malar artery. Being of such importance as an adnexa of the eye, the authors concentrated their attention on its vascularization, which is not well defined. Methods:  Scanning Electronic Microscopy of vascular corrosion casts and intact tissue. Observations:  It was quite interesting to notice the presence of two patterns of vascularization inside the third eyelid. One can say that there are two segmental levels of vessels. In one of these there is a predominance of arteries and veins, while in the other a meshwork of third order arteries, capillaries and post-capillary venules are present. In fact, the branch of the malar artery that reaches the base of the third eyelid divides into smaller branches that cross almost the complete length of the lid giving only a few collateral vessels, in a monopodical way, and only near the free margin of the lid is possible to observe dicothomical ramifications that became rather anastomotic (being anastomoses of type I and II are present) and contribute to the microvascular meshwork. This microvascular net is drained by post-capillary venules and veins that empty as a brush into bigger veins that occupy the same segmental level as the third eyelid artery. Remarks:  This uncommon angioarchitecture is probably an adaptation to the fact that in the medial canthus of the eye this lid has a smaller space and the way of obtaining an efficient vascularization is by going straight to the top of the lid.

Fisiopatologia da Dispneia em doentes cardíacos com Congestão Pulmonar

The purpose of this study was to evaluate whether pulmonary congestion (PC) in cardiac patients may induce changes in the control of breathing or in the respiratory muscles strength, that could be implicated in the genesis of dyspnea in this group of patients. We have compared 48 patients (GI), with a mean age of 61 years and a mean pulmonary capillary (wedge) pressure of 19.9 mmHg, with a group of 35 controls (GII) with a mean age of 62 years. We have performed the following measurements: pulmonary volumes and capacities using the helium dilution method, airway flows by pneumotachography. We also determined the occlusion pressure and the ventilatory response to C02, with simultaneous quantification of dyspnea using a visual analogue scale. Measurements of maximal inspiratory and expiratory pressures were also performed. PC patients underwent right heart catheterization and assessment of cardiac output by thermodilution technic. Cardiac patients had an increase in the central output to breathing (P0.1 GI-1.7 cmH20/GII - l.35 cmH20; < 0.001), probably due to the respiratory restrictive pattern. Because we found no changes in the P0.1, during C02 stimulation, we admit that the central command is not altered. During the C02 stimulation, and for a similar increase in ventilation, the cardiac patients showed a higher degree of dyspnea. The reduction of maximal respiratory pressures and the increased basal respiratory drive can be important factors in the generation of dyspnea presented by these patients.