Potassium and blood vessels.

Intraarterial infusion of potassium causes vasodilation whereas reduction of the potassium concentration in the inflowing blood causes vasoconstriction. These responses have always been puzzling since the predicted effects from the Nernst equation are just the reverse. Recent evidence suggests that they result form effects on the activity of sarcolemmal Na, K ATPase in the vascular smooth muscle cell which influence the electrogenic NaK pump. The possible relevance of these findings is discussed.     

Influence of long-term head-down body position on innervation density in extremity blood vessels

The aim of the present study was to quantitate and compare the density of nerve terminals (NTD), as well as of their synaptic vesicle population (SyVD) in saphenous and brachial vein and artery, obtained from rats maintained in the horizontal or head-down tilted (HDT) position for two weeks. The same technique was applied as that for the head-up tilt study.     

The cephalic neural crest provides pericytes and smooth muscle cells to all blood vessels of the face and forebrain

Most connective tissues in the head develop from neural crest cells (NCCs), an embryonic cell population present only in vertebrates. We show that NCC-derived pericytes and smooth muscle cells are distributed in a sharply circumscribed sector of the vasculature of the avian embryo. As NCCs detach from the neural folds that correspond to the future posterior diencephalon, mesencephalon and rhombencephalon, they migrate between the ectoderm and the neuroepithelium into the anterior/ventral head, encountering mesoderm-derived endothelial precursors. Together, these two cell populations build a vascular tree rooted at the departure of the aorta from the heart and ramified into the capillary plexi that irrigate the forebrain meninges, retinal choroids and all facial structures, before returning to the heart. NCCs ensheath each aortic arch-derived vessel, providing every component except the endothelial cells. Within the meninges, capillaries with pericytes of diencephalic and mesencephalic neural fold origin supply the forebrain, while capillaries with pericytes of mesodermal origin supply the rest of the central nervous system, in a mutually exclusive manner. The two types of head vasculature contact at a few defined points, including the anastomotic vessels of the circle of Willis, immediately ventral to the forebrain/midbrain boundary. Over the course of evolution, the vertebrate subphylum may have exploited the exceptionally broad range of developmental potentialities and the plasticity of NCCs in head remodelling that resulted in the growth of the forebrain.     

Early postoperative efficacy of fibrin glue in face lifts: a prospective randomized trial

Fibrin glue is increasingly finding use in plastic surgery at the clinical and basic science level. The authors conducted a prospective, nonblinded, randomized, controlled trial in 30 patients undergoing face lifts to examine the efficacy of fibrin glue in reducing postoperative wound drainage, hematomas, and, in particular, the degree of ecchymosis and edema at 24 hours and at 8 days. Patients were their own controls and were randomized to have the glue on one side of their face only to compare the glued and unglued sides. The patients ranged in age from 42 to 72 years (mean age, 60 years). There was one major hematoma requiring surgical evacuation. In the remaining 29 patients, the mean drainage on the glued side was 26 ml, compared with 33.5 ml on the control, unglued side. This difference was statistically significant numerically (p = 0.037) but was not thought to be surgically significant. Comparing scores among grades of hematomas, ecchymosis, and edema, there were minimal differences between the glued and unglued sides. This study suggests that fibrin glue may not be as beneficial as previously thought in reducing ecchymosis and edema in the early postoperative period after face lifts, and its future role is discussed.     

A prospective, randomized, double-blind trial of the use of fibrin sealant for face lifts.

Fibrin sealant imitates the final phase of the blood coagulation process. Fibrinogen is converted into fibrin on a tissue surface by the action of thrombin, which is then cross-linked by factor XIIIa, creating a mechanically stable fibrin network. This fibrin network is thought to reduce the amount of postoperative bleeding by sealing capillary vessels and allowing raw operative surfaces to adhere.The authors conducted a prospective, double-blind, randomized, controlled trial on the use of fibrin sealant in 20 consecutive patients undergoing bilateral face lifts by the same surgeon. Each patient was randomized for the use of fibrin sealant on either the right or the left side with the contralateral side acting as the control. Total drainage was recorded on each side for 24 hours before drains were removed. The age range of the patients in the trial (all of whom were women) was 44 to 70 years (mean, 55). The side treated with fibrin glue had a median drainage of 10 ml and the control side 30 ml. The Wilcoxon signed rank test shows a significant difference in drainage between sides (p = 0.002). The reduction in postoperative drainage could also reduce pain and bruising, increasing patient satisfaction with this procedure. The need for drains may also be obviated.     

Isolating and defining cells to engineer human blood vessels

A great deal of attention has been recently focused on understanding the role that bone marrow-derived putative endothelial progenitor cells (EPC) may play in the process of neoangiogenesis. However, recent data indicate that many of the putative EPC populations are comprised of various haematopoietic cell subsets with proangiogenic activity, but these marrow-derived putative EPC fail to display vasculogenic activity. Rather, this property is reserved for a rare population of circulating viable endothelial cells with colony-forming cell (ECFC) ability. Indeed, human ECFC possess clonal proliferative potential, display endothelial and not haematopoietic cell surface antigens, and display in vivo vasculogenic activity when suspended in an extracellular matrix and implanted into immunodeficient mice. Furthermore, human vessels derived became integrated into the murine circulatory system and eventually were remodelled into arterial and venous vessels. Identification of this population now permits determination of optimal type I collagen matrix microenvironment into which the cells should be embedded and delivered to accelerate and even pattern number and size of blood vessels formed, in vivo. Indeed, altering physical properties of ECFC-collagen matrix implants changed numerous parameters of human blood vessel formation, in host mice. These recent discoveries may permit a strategy for patterning vascular beds for eventual tissue and organ regeneration.     

Adrenergic innervation of human mesenteric blood vessels.

A fluorescent histochemical technique has been applied to study the adrenergic innervation of human superior mesenteric arteries obtained at autopsy. Specific catecholamine fluorescence was demonstrated in the smaller branches of this artery taken from three infants and one child. No specific fluorescence was seen in arteries from three adult subjects.     

Nitric oxide as a signal in blood vessels.

In the five years since the discovery that nitric oxide is produced as a signal in blood vessels, a great deal has been discovered about the processes involved. This article reviews current knowledge about the vascular cell synthesis, effects and subsequent destruction of this messenger molecule.     

Relationship of blood vessels to small intensely fluorescent cells in the autonomic ganglion.

In our experiments we observed the relationship of the blood vessels to the small, intensely fluorescent cells (SIF cells) in the lower mesenteric ganglion of the cat. We injected the solution of Evan's blue into the ganglia and processed them with the fluorescent histochemical method by Falck and Hillarp. We observed that the SIF cells are placed in the ganglia closely to the blood vessels or closely round them. When observing lager groups of SIF cells placed at the edge of the ganglia a dense network of the blood vessels was observed among these cells.     

Smooth muscle cells of blood vessels in response to vibration

In smooth muscle cells of the rat femoral arteries, when the animals have been subjected to a prolonged general vibration (100 Hz, amplitude 0.5 mm), size of their nuclei increases. The nuclei of myocytes in the posterior vena cava in the experimental animals are also larger than in the intact ones. Increase of the volumes of the smooth muscle cells in the posterior vena cava is not connected with the increase of the level of their ploidity. In the control animals accumulations of glycogene are revealed in the smooth muscle cells situating along the course of the internal elastic membrane of the femoral arteries. Single glycogene granules are found in other areas of the t. media. The type of glycogene distribution in the muscle layer of the femoral arteries remains the same in the rats after vibration, however, its general content is essentially decreasing.     

Use of Lactobacillus to prevent infection by pathogenic bacteria

This review focuses on the use and potential of Lactobacillus to prevent infections of the urogenital and intestinal tracts. The presence and dominance of Lactobacillus in the vagina is associated with a reduced risk of bacterial vaginosis and urinary tract infections. The mechanisms appear to involve anti-adhesion factors, by-products such as hydrogen peroxide and bacteriocins lethal to pathogens, and perhaps immune modulation or signaling effects. The instillation of Lactobacillus GR-1 and B-54 or RC-14 strains into the vagina has been shown to reduce the risk of urinary tract infections, and improve the maintenance of a normal flora. Ingestion of these strains into the gut has also been shown to modify the vaginal flora to a more healthy state. In addition, these strains inhibit the growth of intestinal, as well as urogenital pathogens, colonize the gut and protect against infections as shown in mice. Other probiotic strains, such as Lactobacillus GG, have been shown to prevent and treat gastroenteritis caused by rotavirus and bacteria. Given that lactobacilli are not the dominant commensals in a gut which comprises around 10(10) organisms, much work is still needed to define the mechanisms whereby GR-1, RC-14, GG and other strains contribute to health restoration and maintenance. Such critically important studies will require the medical science community to show a willingness to turn away from pharmaceutical remedies as the only solution to health and disease.     

Superficial anastomoses of blood vessels in the human heart.

We investigated superficial interarterial, intra-arterial, arterio-venous and veno-venous anastomoses in 100 hearts from men and women taken at random who died at 20-85 years of age. By means of careful dissection and injection into the blood vessels of a differently stained 12% solution of vinilit in acetone, we studied the number and localization of the anastomoses and their appearance. Interarterial anastomoses, i.e. anastomoses between the ramification of the left and the right coronary artery, were detected in 33 hearts. Intra-arterial anastomoses, i.e. anastomoses between the ramifications of one and the same artery, were seen in 5 hearts. Arterio-venous anastomoses were found in 39 hearts. Veno-venous anostomoses were found in 49 hearts. The veno-venous anastomoses display a great many variations, being commonly the regular finding in human veins.