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At least 433 records · Page 24Linked to original sources
PubMed2005

[The influence of the estrogens on a retinal blood vessels].

PURPOSE: To define the influence of the estrogens on a retinal blood vessels. MATERIAL AND METHODS: 20 healthy women, mean age 23.5 +/- 1.55 with normal laboratory investigations and with regular fundus and blood vessels appearance, participated in our study. Fundus examination was performed with fundus camera Canon NF 505 and with HRT II. The measurements were made before estrogens application (300 microg dermal plasters) and 36 hours after the application in 4th and 6th day of a period. RESULTS: The difference between the size of the retinal vessels before and after estrogens application was significant in all cases. In the main branches the increase of a vessel's diameter was 4.4% to 11.22% (mean 7.61% +/- 3.210%), p<0.05. The increase in a smaller branches of central retinal artery balanced from 1.2% to 9.2% (mean 5.47 +/- 4.11%), p<0.05. CONCLUSIONS: Estrogens have a great vasodilatation effect on a retinal blood vessels. The level of the dilatation after the estrogens' application is about 8% in main branches and about 5% in a smaller vessels.

Adult↗
PubMed2005

Regional and developmental variations of blood vessel morphometry in the chick embryo chorioallantoic membrane.

Avian eggs contain all the necessary materials for embryonic development except for oxygen, which diffuses in from the environment via pores in the hard, calcified eggshell to the chorioallantoic membrane (CAM), the respiratory organ, which is rich in blood vessels. An air cell is formed at the blunt pole of the egg between the two membranes of the eggshell and enlarges during incubation due to water vapor loss. In this study of the CAM of chicken eggs, we compared blood vessel numerical density [N(A(v))], area fraction of blood vessels [A(A(v))], CAM thickness (D(CAM)), total length of blood vessels (L) and surface area of the CAM attached to the eggshell (CAMre) with those under the air cell (CAMac) during incubation. We found that N(A(v)), A(A(v)), D(CAM) and L of the CAM increase with embryonic age and development. The N(A(v)), A(A(v)) and L under the air cell were higher in relation to the rest of the CAM at all ages tested, while the D(CAM) under the air cell was always lower than around the rest of the egg. Since the eggshell over the air cell has a relatively greater porosity, and the respiratory gas exchange ratio there is higher than at other areas of the egg, there is a correlation between all the above morphometric data and the eggshell porosity. This suggests optimization of embryonic gas exchange in the chicken egg. We would like to propose that, during natural incubation, an increased gas diffusion under the air cell, together with increased blood vessel numerical density, may compensate for covering of the central part of the eggshell by the incubating parent.

Age Factors↗
PubMedDate not supplied

[The internal thoracic blood vessels (internal thoracic arteries and veins) and their practical significance].

Internal thoracic blood vessels (A. et Vv. thoracicae internae) are parietal vessels of the thoracic anterior wall. Because of their position, they are often exposed to injuries during the fracture of the ribs and the sternal bone. These facts require a general knowledge about the anatomical variations of these vessels, specifically the knowledge concerning their mutual relationship, their anastomoses and their distance from the lateral margins of the sternal bone. Due to the poor and different data in the available literature, we directed our investigations towards the study and confirmation of the described anatomical variations of the internal thoracic blood vessels. In this study we investigated the distance between the internal thoracic artery and the lateral margins of the sternal bone, the level of its bifurcation, the number of the internal thoracic veins and anastomoses between them. The investigation was carried out on 300 formalin specimens consisting of the anterior wall of the thorax (persons of different ages and sexes) by using the method of dissection and the method of contrast injection. In adults (200 specimens), the distance between the arterial trunk and the lateral margin of the sternal bone was not equal in the first fifth or sixth intercostal spaces, but in children up to five years of age (100 specimens), the distance was almost the same. In adults, the internal thoracic artery was nearest to the sternal bone in the first intercostal space, but going downward the artery was gradually more and more distant from the sternum and in the sixth intercostal space the distance measured approximately from 11 mm to 13 mm. In children, the distance of the artery from the lateral margin of the sternal bone, just in the above mentioned intercostal spaces, was from 5 mm to 10 mm. There was no difference according to sex in any of the two groups. Most frequently, the internal thoracic artery gave off its terminal branches at the level of the sixth costal cartilage (adults--35% and children--45%), and most rarely, the bifurcation of the artery was at the level of the seventh costal cartilage (adults--10% and children--8%). The internal thoracic vein that accompanies the same named artery, could be either single or double, on one or both sides. In cases of double veins-the artery was situated between the two of them, but in cases of single vein-the vein was located medially to the artery. In 82% of cases in the adult group, and in 69% of cases in the children-group, there were two veins accompanying the artery. The right and the left internal thoracic veins were connected in the region of the sternal bone by the retrosternal venous net (specifically in the region of the manubrium) and by one venous vessel lying in front of the xiphoid process. According to the position and the course of that venous vessel it could be called "arcus venosus prexiphoideus". The internal thoracic blood vessels were enclosed by the unique fascial sheath. They were superiorly separated from the costal pleura by the endothoracic fascia and inferiorly by the transversal thoracic muscle (m. transversus thoracis). The safest approach to the internal thoracic artery was at the level of the second and the third intercostal space. During the approach through some of the lower intercostal spaces it was necessary to be very careful because they could be narrowed at their anterior ends.

Adult↗
PubMed1976

[Testing of the resistance of peripheral blood vessels by ultrasound].

The authors carried, out a test on the resistance of blood vessels to the flow of blood, (namely arteries), using an apparatus known by the name SONICAID EM 220. The SONICAID is a portable ultrasound generator and receiver weighing 3.5 kg. It consists of a transducer, and an ultra sound generator. The transducer, (which is about as large as a matchbox), receives the generated ultrasound signal, transforms it to an audible signal, and sends it to the main via a cable. The amplified signal can be monitored through a built-in speaker, or through headphones. The signal can also be recorded on tape, but th is feature was not included in the authors' unit. The SONICAID is based on the Doppler Principle; interference of reflected waves. If the generated ultrasound waves reach moving matter, (in this case a stream of blood), they are reflected back in such a way that they reach the transducer as interference waves. This signal is not unlike the sound produced by the heart during systolic contraction, or by stenotic blood vessels. The authors examined 21 ill patients with normal circulation using the SONICAID, and found it difficult to register the signals. The arteries of the forearm and lower leg could not be convincingly registered because it was difficult to determine the proper angle required to pick up the signals. In addition the area in which the signals could be picked up did not always concide with the anatomical position of the artery. These are the factors which the authors used to explain the rather inanccurate results. In 9 individuals (38%), the SONICAID indicated pathooligcal findings (false positive results). Later the authors examined 23 patients with previously confirmed vascular diseases, and obtained 15 pathological findings (65%). With 4 individuals, a false positive result was obtained, and wit the remaining 4, a false negative result, or a total of 8 false results (35%). Based on these results, the authors concluded that; the relatively large percentage of false results, the difficulty of demonstrating normal findings, and the relatively long examination time make this method of examination rather uncertain. The subjectivity of the person conducting the examination also influences the interpretation of the sounds emitted by the machine, which in turn influences the results. Objectivization, and documentation of such results is not certain. As a result, This method has no advantage over the oscillograph, and clinical examination. Such a conclusion however does not justify discontinuing the use of the more sophisticated diagnostic tools and methods used in vascular surgery.

Blood Vessels↗
PubMed1990

["Ex situ" reconstruction of blood vessels of the renal hilus in experimental transplantation in dogs].

The variations of arterial and venous hillar blood vessels in human kidneys are numerous and surgical transplant teams have to know them. It is very important during doner-nephrectomy for transplantation. Sometimes, after doner, nephrectomy and kidney cold perfusion with Collins, there is a need for vascular repair of kidney hillar blood vessels, using microvascular surgical technique. The aim of this repair is: to have a kidney with main renal artery of good length and size and with main renal vein of good length and size. This procedure is called: extracorporeal "ex-situ" vascular repair of kidney hillar blood vessels. In the period 1987-1988, in our Experimental Surgery Unit a total of 20 dogs were operated on (kidney autotransplantation) and only in four (4) dogs we found variations in numbers of kidneys arterial and venous hillar blood vessels (20%) and repaired those vessels after cold perfusion of kidney. One dog had kidney with double renal arteries and double renal veins, and we had to make fusion the both arteries into the main renal artery of good size (5 mm) and the both veins into the renal vein of good size (12 mm). Three dogs had kidneys with main trunk of renal artery and one important separate polar renal artery, and we had to make implantation of separate polar renal artery into the main trunk of renal artery (end-te-side vascular anastomosis). For those vascular reconstructions we used polipropilene 6-o or -o as suturae material and binocular (magnification 2.5 x). The hemodynamically results of those reconstructions immediately after kidney implantation were very satisfactory.

Animals↗
PubMed2002

A blood vessel exposed to ultrasound: a mathematical simulation of the temperature field.

In this article we present a mathematical simulation of the temperature field in and around a blood vessel when it is sonicated by a focused ultrasound beam. A simplified geometry is considered: a cylindrical blood vessel is embedded in tissue parallel to a flat skin surface. The ultrasound transducer is placed on the skin above the blood vessel, perpendicular to the skin surface. The 3D geometry of the problem is simplified by transformation, which maps the domain into a parallelepiped. A computational algorithm and computer program were developed. The simulation provides the conditions for successful occlusion of a blood vessel and demonstrates the significant role of the blood flow rate on the temperature difference between the vessel wall and the surrounding tissue. Comparing the predictions with published experimental data tested the validity of the method.

Blood Flow Velocity↗
PubMed1984

Pathogenesis of the so-called cystic adventitial degeneration of peripheral blood vessels.

Eleven cases of cystic adventitial degeneration of peripheral blood vessels were examined by light and (in three instances) by electron microscopy. Eight cases were in arteries, three were detected in veins. In six cases a cellular lining of the cysts was observed. Ultrastructurally the lining cells resembled synovial mesothelial cells. In three cases a pedicle connection was detected between the adventitial cysts and an adjacent joint. In one case such a pedicle could be followed to its junction with the knee joint capsule and was also lined by synovial mesothelium. These findings indicate that the so-called cystic adventitial degeneration is not a primary dysplasia of the blood vessel wall but originates from ectopic tissue of a joint capsule or bursa.

Adult↗
PubMed1995

Studies on pregnancy hypertension and IUGR-SFD: effects of drugs on the blood vessels in the placenta of pregnant SHRSP.

1. Based upon our previous work, we came to the conclusion that a decrease in placental blood volume was a possible factor behind intrauterine growth retardation (IUGR) in pregnancy-induced hypertension. 2. In a second study, we used an image analysis system to measure cross-sectional areas and wall thicknesses of central blood vessels of the spiral artery, the so-called 'central artery'. 3. It was thought that one of the more basic factors behind IUGR in pregnancy-induced hypertension might possibly be narrowings and spasms of the maternal placental blood vessels. 4. In this study, we found that the three drugs we used (MgSO4 center dot 7H2O, Solcoseryl and KCl) all resulted in an enlargement of the cross-sectional areas of the maternal blood vessels, and that MgSO4 center dot 7H2O, in particular, also relaxed maternal blood vessel spasms in SHRSP placenta.

Animals↗
PubMed1989

Mosaic reconstruction of blood vessels in mouse neocortical tissue transplanted into the third ventricle of rat brain.

Newborn mouse neocortical tissue was transplanted into the third ventricle of rat brain and the reconstruction and the origin of the blood vessels were investigated by using a monoclonal antibody against mouse endothelial surface antigen-1 (MESA-1). It was clearly demonstrated that some of the blood vessels in the graft originated in the donor mouse neocortical tissue. An India ink perfusion experiment revealed that the blood was supplied to the MESA-1-positive blood vessels. Furthermore, electron microscopic immunohistochemical studies demonstrated the existence of a mosaic reconstruction of blood vessels which consisted of mouse- and rat-derived vascular endothelial cells. It was concluded that the blood vessels originating in the donor tissue and those originating in the host tissue inoculate with each other in the grafted tissue.

Animals↗
PubMed2006

A sandwich tubular scaffold derived from chitosan for blood vessel tissue engineering.

Many materials have been investigated in blood vessel tissue engineering, such as PGA, PLGA, P4HB. However, chitosan is not mentioned in the arena. This study aimed to develop a chitosan-based tubular scaffold and examine its feasibility of being applied in this field. Briefly, a knitted chitosan tube was dipped into chitosan solution (2%, w/v) and dried, then its inner and outer surface was mantled with a layer of chitosan/gelatin (4:1, w/w) complex solution, and then freeze-dehydrated. In vitro characterization showed that the scaffold had a wall of 1.0 mm in thickness with a sandwich structure, and a porosity of 81.2%. The pore diameter was 50-150 microm and could be regulated by varying freezing conditions. The scaffold possessed proper swelling property, burst strength of almost 4000 mmHg, and high suture-retention strength. After degradation for 2 months, the scaffold could maintain enough mechanical strength with an average mass loss of 18.7%. Vascular smooth muscle cells could spread and grow very well on the scaffold. This study provided a novel method to fabricate chitosan and its complex into a tubular scaffold and demonstrated the feasibility of the scaffold employed in the field of blood vessel tissue engineering.

Animals↗
PubMed1981

Effects of a progesterone-releasing intrauterine contraceptive device on endometrial blood vessels: a morphometric study.

The concentration of microscopically detectable blood vessels was significantly lower in endometrium exposed to progesterone-releasing intrauterine contraceptive devices (IUDs) than in control endometrium (mean vessel density 2.39 and 3.92, respectively). The percentage of vessels with defects was significantly higher in IUD samples (35.0%) than in control samples (13.4%). There was no significant difference in hemostatic response to vessel injury between the IUD and control samples. Although they were more defective than in controls, the blood vessels of progesterone IUD-exposed endometrium were far fewer in number, which may account for significantly less uterine blood loss in the users of these devices. In addition, the progesterone IUDs do not appear to inhibit hemostasis in the endometrium so that blood loss from injured vessels may be minimized.

Endometrium↗
PubMed2002

First-order system least squares for elastohydrodynamics with application to flow in compliant blood vessels.

Mathematical modeling of compliant blood vessels generally involves the Navier-Stokes equations on the evolving fluid domain and constitutive structural equations on the tissue domain. Coupling these systems while accounting for the changing shape of the fluid domain is a major challenge in numerical simulation. Many techniques have been developed to model compliant vessels, but all suffer from disproportionate increase in computational cost as problem complexity increases (i.e., larger domains, more dimensions, and more variables.). Even the best standard methods result in computational cost that typically grows quadratically with the degrees of freedom. Using a least-squares formulation of the problem, elliptic grid generation for the changing fluid domain, and an algebraic multigrid solver for the linear system can overcome many shortcomings of standard techniques. Most notably, the computational cost of solving the problem increases linearly with the degrees of freedom and the associated functional provides an a posteriori error measurement. Least squares represents a systematic approach for formulating the original problem so that the numerical process becomes straightforward and optimal, and it avoids restrictions that often limit other methods. Results are presented for a two-dimensional test problem consisting of a Newtonian fluid with properties of blood in a linear-elastic vessel with properties of smooth muscle.

Computer Simulation↗
PubMed1981

VIP nerve fibres around peripheral blood vessels.

By immunocytochemistry nerve fibres containing vasoactive intestinal polypeptide (VIP) were demonstrated around many peripheral blood vessels in the cat. Such nerve fibres were particularly numerous around arteries in the upper respiratory, gastrointestinal and genito-urinary tracts. They were less numerous around large arteries and veins and seemed to be absent from the blood vessels in liver, spleen and kidney. VIP nerve fibres were few around blood vessels in skeletal muscle and absent in coronary arteries. Administration of VIP in vitro relaxed all arteries tested provided they had been given an increased tone, for instance by preincubation with PGF2 alpha. It is likely that VIP in vascular nerve fibres may participate in the regulation of systemic and local blood flow.

Animals↗
PubMed1995

Occurrence and coexistence of some neuropeptides in nerve fibers supplying the bovine ovary and its extrinsic blood vessels.

Single- and double-labelling immunofluorescence was applied to investigate the occurrence and coexistence of vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP) and substance P (SP) in nerve fibers supplying the bovine ovary as well as its extrinsic blood vessels. We also studied the coexistence of these neuropeptides with tyrosine hydroxylase (TH) and neuropeptide Y (NPY) to determine features of "chemical coding" of nerve fibers innervating this organ. The bovine ovary was found to be supplied by VIP- and SP-immunoreactive (VIP- and SP-IR) nerve fibers. No intraovarian CGRP-IR nerve terminals were detected. Immunoreactivity to VIP was shown in a moderate number of nerve fibers occurring in all ovarian regions - ovarian hilus, cortex and medulla. VIP-IR nerves were found to innervate blood vessels and ovarian follicles, especially primordial and primary ones. Immunoreactivity to SP was detected only in solitary intraovarian nerve fibers which were also encountered in all ovarian regions, but with special preference to ovarian medulla, where they innervated blood vessels. SP-IR nerve fibres were sometimes observed in close vicinity to primordial and primary follicles. Double-labelling immunofluorescence revealed that some VIP-IR nerve fibres supplying intraovarian blood vessels were simultaneously TH- or NPY-IR. Small numbers of VIP-IR fibres contained immunoreactivity to SP. All SP-IR nerve terminals were TH-or NPY-negative. The ovarian artery as well as arteries of the paraovarian plexus were moderately supplied with VIP-, or by single CGRP- or SP-IR nerve fibres. Veins were innervated by only solitary nerve terminals containing these neuropeptides. The following patterns of coexistence were determined in nerve fibres supplying the investigated blood vessels: VIP, VIP/CGRP, VIP/SP, CGRP/SP, VIP/NPY. No distinct differences in the innervation of the ovary and its extrinsic blood vessels between juvenile and adult cows were found.

Age Factors↗
PubMedDate not supplied

[Human blood vessels created with tissue engineering].

Progress in tissue engineering now allows the recreation of functional blood vessels from cultured human vascular cells. When reconstructed under specific conditions, their structure, mechanical properties and function (especially vasomotricity) allow them to be used as human models for studying the biology and pharmacology of blood vessels. These models may help to circumvent the limitations in the obtention and use of native human blood vessels for experimental purpose.

Biomedical Research↗
PubMed1998

cDNA cloning of canine adrenomedullin and its gene expression in the heart and blood vessels in endotoxin shock.

Adrenomedullin (AM) is a potent vasorelaxing peptide isolated from human pheochromocytoma. It is proposed that AM dilates the blood vessels by autocrine or paracrine mechanisms. Our investigation concerned whether the vasodilating function of AM accounts for the hypotension occurring in endotoxin shock. The effect of endotoxin shock on AM gene expression in the cardiovascular system was probed using a canine model. The cDNA encoding the AM precursor in dogs was isolated from cDNA libraries of the adrenal gland and was sequenced. The canine AM precursor is constituted of 188 amino acids and its AM consists of 52 amino acids, similar to human and porcine AM. The dogs were injected intravenously with 2 mg/kg of lipopolysaccharide (LPS) after being anesthetized and intubated. After 4 h, we collected whole blood, the large and small blood vessels, and the heart from our canine model of endotoxin shock, and extracted RNA from those tissues for Northern blot analysis. In the endotoxin shock model, the mRNA levels of the AM had increased in almost all of the blood vessels. These results suggest that AM may dilate the blood vessels systemically, even if AM acts as a local modulator of vascular tone. In addition, the plasma concentrations of the AM were high enough to allow for AM to act as a vasodilating hormone. Consequently, AM may be one of the factors facilitating severe hypotension complicated with endotoxin shock.

Adrenomedullin↗
PubMed1993

Increased endothelin-1 content in blood vessels of deoxycorticosterone acetate-salt hypertensive but not in spontaneously hypertensive rats.

Endothelin-1 (ET-1) is a powerful vasoconstrictor peptide produced in the endothelium of blood vessels that may play an important role in the control of local blood flow and could be involved in the pathogenesis of hypertension. We investigated immunoreactive ET-1 (ir-ET-1) levels in acid extracts from blood vessels of deoxycorticosterone acetate (DOCA)-salt and spontaneously hypertensive rats. We found that segments of thoracic aorta and the mesenteric vascular bed contain significantly more ir-ET-1 (11.84 +/- 0.84 and 17.30 +/- 1.89 fmol, respectively) than uninephrectomized control rats (1.78 +/- 0.20 and 9.19 +/- 0.63 fmol, respectively; p < 0.001). High performance liquid chromatography showed that ir-ET-1 of blood vessels of DOCA-salt hypertensive rats eluted in the same position as synthetic ET-1. Significantly increased ir-ET-1 was localized by immunohistochemistry in endothelial cells of aorta and large and small mesenteric arteries of DOCA-salt hypertensive rats. In contrast to the latter, in spontaneously hypertensive rats, vascular content of ir-ET-1 was similar to that of blood vessels of Wistar-Kyoto control rats, at both 6 and 16 weeks of age. High levels of vascular ET-1 may explain the downregulation of vascular endothelin receptors previously described in DOCA-salt hypertensive rats. Furthermore, this suggests that ET-1 may be involved in the maintenance of high blood pressure in mineralocorticoid hypertension.

Animals↗