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At least 217 records · Page 12Linked to original sources
PubMed1984

Alpha- and beta-blockade in angina pectoris.

Angina pectoris encompasses a clinically diverse group of syndromes in which the common factor is myocardial ischaemia resulting from an imbalance between oxygen requirement and delivery. Anginal pain is most frequently precipitated by exercise, but may occur without any apparent cause at rest. Fixed obstructions in the coronary vessels, often attended by thickening of the overlying coronary artery media, are the most frequent cause of ischaemic cardiac pain. The resulting myocardial fibrosis impairs efficient filling and emptying of the ventricles, further aggravating the functional embarrassment resulting from the reduced coronary blood flow. In stable coronary heart disease the increased energy demands during exercise are associated with the rapid development of a haemodynamic profile characteristic of acute left ventricular failure. This results in further substantial increases in pressure work, wall stress and oxygen consumption of the left ventricle. The reflex sympathoadrenal consequences of these primary haemodynamic changes lead to further mechanical and electrical embarrassment of the ischaemic heart. Increased stimulation of beta 1- and beta 2-receptors in the heart increases heart rate and contractility and thereby myocardial oxygen demand. Increased stimulation of alpha-receptors in the peripheral veins and arteries indirectly increases left ventricular oxygen demand still further by increasing preload and afterload, respectively. The reduced blood flow to the endocardium enhances its sensitivity to increased sympathoadrenal stimulation and facilitates initiation of arrhythmias. Blockade of all adrenergic activity, particularly in the myocardium, coronary arteries and peripheral blood vessels should, therefore, help alleviate the myocardial ischaemia. There is a rational argument for the use of alpha-blockade in coronary heart disease, particularly in conjunction with beta-blockade. Attenuation of the risk of coronary spasm and ventricular arrhythmias and reduction of pressure work and left ventricular afterload are amongst the potential attributes of alpha-blockade. Alone, however, their utility is severely limited by the risks of hypotension and reduction in coronary perfusion pressure and reflex oxygen-wasting tachycardia. Alone, alpha-adrenoceptor antagonists have no place in the treatment of angina pectoris. beta-Adrenoceptor blocking drugs competitively inhibit catecholamines at both cardiac and peripheral vascular beta-adrenergic receptors. Their main advantage is that they reduce many of the important determinants of myocardial oxygen consumption, particularly by reducing the heart rate during exercise.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenergic alpha-Antagonists↗
PubMed2005

Artificial blood vessel: the Holy Grail of peripheral vascular surgery.

Artificial blood vessels composed of viable tissue represent the ideal vascular graft. Compliance, lack of thrombogenicity, and resistance to infections as well as the ability to heal, remodel, contract, and secrete normal blood vessel products are theoretical advantages of such grafts. Three basic elements are generally required for the construction of an artificial vessel: a structural scaffold, made either of collagen or a biodegradable polymer; vascular cells, and a nurturing environment. Mechanical properties of the artificial vessels are enhanced by bioreactors that mimic the in vivo environment of the vascular cells by producing pulsatile flow. Alternative approaches include the production of fibrocollagenous tubes within the recipient's own body (subcutaneous tissue or peritoneal cavity) and the construction of an artificial vessel from acellular native tissues, such as decellularized small intestine submucosa, ureter, and allogeneic or xenogeneic arteries. This review details the most recent developments on vascular tissue engineering, summarizes the results of initial experiments on animals and humans, and outlines the current status and the challenges for the future.

Animals↗
PubMed1982

[The system of blood vessels of the small intestine of ruminants (author's transl)].

The vascular system of the small intestine of sheep, goat, and the bovine was investigated by means of corrosion preparations as well as by light and electron microscopic methods. The jejunal villi are shown to contain a single--in the case of broad villi several--centrally placed arterioles. The arterioles show no ramification, they drain into subepithelial capillaries at the apex of the villus. The subepithelial capillaries are not furnished with precapillarious sphincters. In the lower third of the villi several capillaries fuse together, forming a centrally located venule which in turn passes through the base of the villus and--still above the Tunica muscularis mucosae--opens into a transverse running vein. 2 or more of these transverse running veins join together forming a short vascular trunk which opens into collecting veins of the submucosa. Special sphincters of the peripherous blood vessels of the small intestine like arteriovenous marginal loops, arteriovenous anastomoses of the submucosa, vascular sphincters of the muscularis mucosae or veins which are well known in the literature were not found in domestic ruminants.

Animals↗
PubMed1996

Catecholamine concentrations and contractile responses of isolated vessels from hens treated with cyclic phenyl saligenin phosphate or paraoxon in the presence or absence of verapamil.

Blood samples and vascular segments from the ischiadic artery of hens treated with either cyclic phenyl saligenin phosphate (PSP; 2.5 micrograms/kg, im) or paraoxon (PXN; 0.1 micrograms/kg, im) in the presence or absence of verapamil, a calcium channel antagonist (7 micrograms/kg, im, given 4 consecutive days beginning the day before PSP or PXN administration), were examined 1, 3, 7, and 21 d after PSP or PXN administration in order to determine the contribution of catecholamines and peripheral blood vessel physiology and morphology to organophosphorus-induced delayed neuropathy (OPIDN). The levels of plasma catecholamines were measured by high-performance liquid chromatograpy (HPLC) and indicated a different effect with PSP, which causes OPIDN, and PXN, which does not. PSP treatment elevated the levels of norepinephrine and epinephrine throughout the study, while PXN treatment depressed the levels of these catecholamines. Verapamil treatment attenuated the OP response by approximately 50% for both compounds. Ischiadic vessel segments were isolated from OP-treated hens and perfused at a constant flow rate of 12 ml/min, then examined for their response to potassium chloride (KCl, 3 x 10(-3) M), acetylcholine (ACh), phenylephrine (PE), an alpha 1 adrenergic agonist, and salbutamol (SAL), a beta 2 adrenergic agonist. Agents were delivered in concentrations of 10(-8) to 10(-3) M. Vascular segments did not respond to ACh or SAL at any concentration used. Vessels displayed a significant reduction in contractile response to both KCl (3 x 10(-3) M) and PE (10(-8) to 10(-3) M) 3 and 21 d after exposure to either PSP or PXN. This reduced response was not altered by the presence of verapamil. Innervation of the peripheral vasculature was unchanged after OP treatment. This study indicates that plasma catecholamine levels could be differentially altered by treatment with OPs that do and do not cause OPIDN and suggests that the alterations involve intracellular calcium. In contrast, vascular response of the ischiadic artery was altered following OP treatment, but the effect was not specific for the neuropathy-inducing OP, PSP, and response was not mediated by Ca 2+, nor was it the result of autonomic nerve deterioration.

Acetylcholine↗
PubMed2004

Regional effects of an antivascular endothelial growth factor receptor monoclonal antibody on receptor phosphorylation and apoptosis in human 253J B-V bladder cancer xenografts.

Vascular endothelial growth factor (VEGF) is a key angiogenic factor in a variety of solid tumors, making it one of the most attractive therapeutic targets. VEGF promotes the proliferation, survival, and differentiation of vascular endothelial cells by stimulating autophosphorylation and activation of VEGF receptor-2 (VEGFR-2, fetal liver kinase-1, and kinase insert domain-containing receptor). We developed fluorescence-based, quantitative methods to measure total VEGFR-2, VEGFR-2 phosphorylation, apoptosis, and microvessel density and size within whole tumor cross-sections using a laser scanning cytometer. Using these methods, we characterized the effects of DC101, a blocking antibody specific for murine VEGFR-2, on orthotopic human 253J-BV bladder tumors growing in nude mice. Basal levels of receptor phosphorylation were heterogeneous, with approximately 50% of endothelial cells positive for phosphorylated VEGFR-2 at baseline. DC101 therapy resulted in a 50% decrease in overall VEGFR-2 phosphorylation and a 15-fold and 8-fold increase in endothelial cell (CD31-positive) and tumor cell apoptosis, respectively. DC101 also decreased overall tumor microvessel density, but it mostly affected smaller CD105-negative microvessels located in the periphery of the tumor. Intriguingly, anti-VEGFR-2 therapy resulted in increased mean vessel size and an increase in overall VEGFR-2 levels. Increases in total VEGFR-2 levels were localized to the tumor core and were associated with increased expression of the oxygen-sensitive transcription factor, hypoxia inducible factor-1alpha. These data suggest that VEGFR inhibitors preferentially target discrete populations of tumor endothelial cells associated with the smaller peripheral blood vessels. Thus, agents that target a single receptor (e.g., VEGFR-2) may not be sufficient to completely inhibit tumor angiogenesis.

Animals↗
PubMed1984

Peripheral pressor effects of sympathetic stimulation, noradrenaline, angiotensin II and vasopressin in Brattleboro rats.

The following study was designed to test the hypothesis that peripheral blood vessels of vasopressin deficient (Di/Di) rats are less responsive to pressor substances than normal rats. To address this question, pithed Di/Di and normal Long-Evans rats (LE) were exposed to intravenous injections of arginine-vasopressin, angiotensin II and noradrenaline. In addition, blood pressure increments and noradrenaline release in response to spinal cord stimulation in pithed Di/Di and LE rats were studied. The results show no abnormalities in peripheral vascular sensitivity to any of the pressor substances administered, nor was there any change in blood pressure and sympatho-adrenomedullary response to graded stimulation of the sympathetic outflow from the spinal cord. This study suggests that the failure of vasopressin deficient rats to recover from acute hemorrhage is not due to hyporesponsiveness of the peripheral vasculature to pressor agents but, rather, to the deficiency in the direct pressor effect of vasopressin.

Angiotensin II↗
PubMed2004

[Atherosclerosis in patients hospitalized at the Internal Medicine Clinic in Mostar in the past three years].

UNLABELLED: Atherosclerosis, polygenetic, multifactorial and chronic progressive disease of arteries leaves significant consequences on organs and their systems and cause frequent hospitalisations of patients. Aim found out frequency of atherosclerosis process and its consequences (acute myocardial infarction, cardiomyopathy, cerebrovascular insult, renal diseases and diseases of peripheral blood vessels) together with risc factors (artery hypertension, diabetes mellitus, hyperlipidemia, smoking, obesitas, stress an so on.) at patients of Internal Clinic in Mostar in the last three years (2001; 2002; 2003). RESULTS AND METHODS: During last three years we hospitalised 7278 patients which consequences and manifestations of arterosclerosis process had 4825 patients or 66.29% (male 2595 or 53.7% and female 2230 or 46.22%. Most frequent were CM (1496 or 31%) CAD (1036 or 21.47%) peripheral vessel diseases (169 or 3.5%) and the most significant CVI (104 or 2.15%) which were at our clinic as complication for other internal diseases.

Adult↗
PubMed1997

[Repair and functional reconstruction of war wounds of limbs].

From 1979 to 1994, reparative and reconstructive surgery were used to repair the war injuries of skins, bones, blood vessels and nerves of the limbs in 800 cases. A systematic clinical study was carried out. Many new operative methods were used and the results of treatment were good. Innovations and modifications were made in technique. In 120 cases of war injuries having soft tissues defects including skin and muscles, various tissue transplantations were used with the hope to accomplish one-staged repair of the defect and reconstruction of motor function of muscle. To those infections of bone and joint in war injuries, following early eradication of infected focus, transplantation of musculo-cutaneous flap or omental graft was immediately carried out with the aim to obtain primary healing of the wound. In the treatment of bone defects from war wounds with loss of skin and muscles, the vascularized skeleto-cutaneous graft was used. In the treatment of 150 cases of injury of peripheral nerve from forearms, the result of good to fair rated 68.8 percent for upper extremity and that for lower extremity, it was 62.2 percent. Following the early repair of 500 cases of injury of peripheral blood vessels, the patency rate of the blood vessel was 90 percent. The result following by pass vascular graft in the treatment of forearms injury of blood vessels even with very poor local condition was still very successful.

Adolescent↗
PubMed1992

[Micromorphological studies of the blood vessels of the dental pulp of small ruminants].

The blood vascular supply of the dental pulp of 15 domestic sheep of varying age and sex was investigated using light and electron microscopy. The pulp vascular system is showing arterioles with a media of varying thickness and with endothelial cells of variable structure. In the transitional zone between crown and root pulp, the arterioles are taking a typical S- or U-shaped course. The capillary network of the crown pulp is denser and more regular than that in the root pulp. In addition to the capillaries lined by a continuous endothelial tube, there may be others with a typically fenestrated endothelial lining. Specialised vascular structures of the peripheral blood vessels, especially arterio-venous anastomoses as described in man, have not been observed in the sheep.

Animals↗
PubMed2001

Real-time spatial compound imaging: application to breast, vascular, and musculoskeletal ultrasound.

Real-time spatial compound imaging (SonoCT) is an ultrasound technique that uses electronic beam steering of a transducer array to rapidly acquire several (three to nine) overlapping scans of an object from different view angles. These single-angle scans are averaged to form a multiangle compound image that is updated in real time with each subsequent scan. Compound imaging shows improved image quality compared with conventional ultrasound, primarily because of reduction of speckle, clutter, and other acoustic artifacts. Early clinical experience suggests that real-time spatial compound imaging can provide improved contrast resolution and tissue differentiation that is beneficial for imaging the breast, peripheral blood vessels, and musculoskeletal injuries. Future development of real-time spatial compound imaging will help address the bulk of general imaging applications by extending this technology to curved array transducers, tissue harmonics, panoramic imaging, and three-dimensional sonography.

Breast Diseases↗
PubMed1997

Long-term vascular access for hemodialysis using silicon dual-lumen catheters with guidewire replacement of catheters for technique salvage.

Difficulties in creating vascular access in patients on hemodialysis are encountered in most dialysis centers. This is usually due to a lack of suitable peripheral vessels due to previous access surgery in patients on long-term hemodialysis, but also may be seen in some patients de novo, particularly diabetics and patients with peripheral vascular disease. Surgical techniques used to overcome this problem vary depending on patient characteristics and, to a certain extent, on local expertise/preference. We report our experience of using silicon dual-lumen hemodialysis catheters over a 3-year period; during this time, 54 catheters were inserted into 32 hemodialysis patients. The indication for this procedure in 52 catheters (31 patients) was either exhausted vascular access or obvious difficulty identifying a suitable peripheral blood vessel. Of the catheters inserted, 20 were placed into subclavian veins by primary insertion (ie, patients did not have existing subclavian catheter); 34 were replaced over a guidewire (a procedure used to allow technique salvage). The catheter survival rate was 72.7% at 90 days and 48.7% at 1 year. Corresponding rates at 90 days and 1 year for technique survival were 93.3% and 81.8%, respectively. The mean catheter and technique survival was 387 (95% confidence intervals [CIs], 273, 502) and 844 (95% CIs, 684, 1,005) days, respectively. Poor flow accounted for 70.4% of catheter failures and, despite 18 episodes of catheter-related sepsis, no catheters were lost due to infection. Factors identified as leading to reduced catheter survival were left-sided placement and catheter tip placement in the superior vena cava (as opposed to right atrial placement). We did not observe poorer survival or increased sepsis in catheters replaced over a guidewire, and would advocate this technique as a means of salvage in this group of patients.

Adult↗
PubMed2004

Aging enhances vascular dysfunction induced by the Alzheimer's peptide beta-amyloid.

Aging is a major risk factor for Alzheimer's disease and the evidence suggests a role for cerebrovascular pathology in cognitive dysfunction. The hypothesis in this study is that aging is a significant risk factor in the effect of the Alzheimer peptide beta-amyloid on endothelium-dependent function of cerebral and peripheral vessels. The diameter response to acetylcholine, an endothelium-dependent vasodilator, was recorded in pressurized segments of rat posterior cerebral vessels from mature (3 months) and aged (20 months) rats. The threshold concentration of beta-amyloid for a significant decrease in the response to acetylcholine was lower in vessels from aged rats (10(-9) M) than in vessels from mature rats (10(-8) M). The threshold concentration of beta-amyloid for a significant decrease in the sensitivity to acetylcholine was lower for ring segments of aorta from aged rats (10(-10) M) than for aorta from mature rats (10(-8) M). Structural changes of the endothelium were first observed in electron micrographs of aorta from aged rats when the concentration of beta-amyloid was 10(-8) M, whereas structural changes in aorta from mature rats did not occur until the concentration of beta-amyloid was increased to 10(-7) M. The results suggest that aging increases the susceptibility of cerebral and peripheral blood vessels to beta-amyloid related dysfunction and that functional change precedes structural change.

Acetylcholine↗
PubMed1991

[Experimental study on the characteristic features of sympathetic nervous system reactions in dogs with obstructive jaundice].

Possible abnormalities in the sympathetic nervous system responsible for circulatory disturbances with obstructive jaundice were investigated by determining the reactions of the heart and peripheral blood vessels using alpha.beta receptor stimulants or blockers. Mongrel dogs were randomly assigned to three groups: untreated (UT) and sham-operated (SO) controls and 3-week-old bile duct ligated (BDL). Under anesthesia with Nembutal, circulatory parameters and blood catecholamine concentration were measured. In term of alpha- and beta-adrenergic reactions, reactions in the sympathetic nervous system to alpha- and beta-receptor stimulants were examined. Mean arterial pressure (MAP) and heart rate were used as an alpha-adrenergic parameter and a beta-adrenergic parameter, respectively. The hemodynamic study in BDL group was characterized by a reduction in MAP (p less than 0.05), total peripheral resistance (p less than 0.005) and left ventricular stroke work (LVSW) (p less than 0.05) and by an increase in cardiac index (p less than 0.05). The blood norepinephrine concentration was significantly increased in jaundice (p less than 0.01). Reaction to the beta-receptor stimulant was significantly decreased in BDL group. In response to the alpha-receptor stimulant, lower reactivity was found in some animals in BDL group in comparison to SO group. Taking this into consideration with the increase in blood norepinephrine and the decrease in LVSW, the presence of abnormalities particularly in the beta-adrenergic system (receptor, cardiac muscle etc.) in jaundice is suggested to be a characteristic feature of reactions in the sympathetic nervous system. Such abnormalities are speculated to be responsible for postoperative shock.

Animals↗
PubMed1977

Lack of bronchial beta adrenoceptor resistance in asthmatics during long-term treatment with terbutaline.

The increasing mortality in acute asthma noted during the sixties has been ascribed to resistance of the beta 2 receptors of the bronchi due to treatment with beta-stimulating drugs. This study questions that theory. Eight patients with reversible airways obstruction were studied. Treatment with oral terbutaline 5 mg 3 times a day was given for 1 yr. Thereafter, terbutaline as metered aerosol was added in the dose of 2 puffs (0.5 mg) 4 times a day for 4 days and 6 puffs (1.5 mg) 4 times a day for further 4 days. The responsiveness of the receptors of bronchi, heart, skeletal muscles, and peripheral vessels was tested before and after 1, 2, 3, 6, 9, and 12 mo of treatment with oral terbutaline and after the two 4-day periods with inhaled terbutaline. The receptors were tested by infusion of increasing doses of isoprenaline, so that dose-response curves for isoprenaline were recorded. No signs of resistance of the beta 2 receptors of the bronchi developed during the terbutaline treatment period. Thus no even spray in moderate overdose caused resistance. Within 1 mo of treatment with oral terbutaline, resistance developed to the tremorogenic effect of terbutaline. Six of the 8 patients showed no signs of development of resistance to the chronotropic effect of isoprenaline. No signs were found of resistance of the beta 2 receptors of peripheral blood vessels.

Adult↗
PubMed2006

The vascular endothelium in hypertension.

The vascular endothelium plays a fundamental role in the basal and dynamic regulation of the circulation. Thus, it has a crucial role in the pathogenesis of hypertension. A spectrum of vasoactive substances is synthesised in the endothelium; of these, nitric oxide (NO), prostacyclin (PGI2) and endothelin (ET)-1 are the most important. There is a continuous basal release of NO determining the tone of peripheral blood vessels. Systemic inhibition of NO synthesis or scavenging of NO through oxidative stress causes an increase in arterial blood pressure. Also, the renin-angiotensin-aldosterone system has a major role in hypertension as it has a direct vasoconstrictor effect and important interactions with oxygen free radicals and NO. Prostacyclin, in contrast to NO, does not contribute to the maintenance of basal vascular tone of conduit arteries, but its effect on platelets is most important. ET acts as the natural counterpart to endothelium-derived NO and has an arterial blood pressure-raising effect in man. Anti-hypertensive therapy lowers blood pressure and may influence these different mediators, thus influencing endothelial function. In summary, due to its position between the blood pressure and smooth muscle cells responsible for peripheral resistance, the endothelium is thought to be both victim and offender in arterial hypertension. The delicate balance of endothelium-derived factors is disturbed in hypertension. Specific anti-hypertensive and anti-oxidant treatment is able to restore this balance.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Successful limb reperfusion using prolonged intravascular shunting in a case of an unstable trauma patient--a case report.

When peripheral vascular injuries present in conjunction with life threatening emergencies, controlling hemorrhage from a peripheral blood vessel may take initial priority, however, sacrificing a limb to preserve life is a well-established dictum. The use of intravascular shunts has allowed arterial and venous injuries to be controlled and temporized while treating other injuries. Typically, intravascular shunts are used for short time periods while orthopedic injuries are repaired or other life threatening injuries are managed. The following case demonstrates the long-term use of an intravascular arterial shunt to treat a traumatic transection of the common femoral artery and vein in a patient with an open pelvic fracture from blunt trauma. A 20-year-old woman fell between a subway platform and an oncoming train. She sustained a crush injury to her lower extremity and pelvis as she was pinned between the train and platform. The patient presented with active hemorrhage from a groin laceration, quickly became hemodynamically unstable, and was brought to the operating room. In addition to a pelvic fracture with massive pelvic hematoma she sustained a complete transection of the bifurcation of the common femoral artery (CFA), the common femoral vein (CFV), and associated orthopedic injuries. Vascular shunts were placed in the common femoral artery and vein. The patient became hypotensive from an expanding retroperitoneal hematoma. Pelvic bleeding was controlled with angioembolization and the venous injury was repaired. At this time the patient became cold, acidotic, and coagulopathic. It was thought unsafe to proceed with the arterial repair and it was elected to keep her arterial shunts in place and perform a planned reexploration in 24 hours after correcting her physiologic status. The patient returned to the operating room for an elective repair of her CFA the following day. Her shunt had remained patent throughout this time. She underwent a reverse saphenous vein graft from her CFA to her SFA. After a prolonged hospital course she was ultimately transferred to a rehabilitation center with intact pulses in both lower extremities. This case demonstrates the effectiveness of prolonged (>6 hours) use of an intravascular shunt as part of damage control surgery for peripheral arterial and venous injuries. In a patient who would otherwise undergo an amputation for their injury, the risk of shunt thrombosis, or infection, during damage control resuscitation may not be a contraindication for placement.

Adult↗
PubMed2002

Dermal microdialysis provides evidence for hypersensitivity to noradrenaline in patients with familial dysautonomia.

OBJECTIVES: To use the technique of dermal microdialysis to examine sensitivity of skin vessels to noradrenaline (NA) in patients with familial dysautonomia (FD) and in healthy controls. METHODS: In 14 patients with FD and 12 healthy controls, plasma extravasation, local laser Doppler blood flow, and skin blanching were observed before, during, and after application of 10(-6) M NA through a microdialysis membrane, located intradermally in the skin of the lower leg. RESULTS: Maximum local vasoconstriction measured by laser Doppler blood flow did not differ between patients with FD and controls. In contrast, patients with FD had an earlier onset of vasoconstriction (p = 0.02). Moreover, reaction to NA was more prominent and prolonged in FD, shown by a larger zone of skin blanching around the microdialysis membrane (p < 0.001) and delayed reduction of the protein content in the dialysate after termination of NA application (p = 0.03). CONCLUSION: These data support the hypothesis that peripheral blood vessels of patients with FD show a denervation hypersensitivity to catecholamines. This may be one mechanism contributing to the major hypertension that frequently occurs during "dysautonomic crises" in FD.

Administration, Cutaneous↗