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PubMed1986

Studies on the functional morphology of rat ocular vessels with scanning electron microscopy.

Tests are still lacking about the suitability of scanning electron microscopy (SEM) of vascular resin casts to show different functional states of peripheral blood vessels. With the aid of a vitalmicroscopic device, we tried to elaborate a vascular casting method using the model of the albino rat iris vasculature. Functional variations of the vasculature were induced by local application of epinephrine to one eye using the untreated fellow eye as a control. It was found that if our modification of Araldite plastic is injected via a systemic access and without preceding rinsing with fixatives or salt solutions there is a good correlation between the vessel diameters seen in SEM of resin casts and the vessel diameters found in the vitalmicroscopic observations. Thus, this method appears also suitable for studying the effect of vasoactive substances.

Animals↗
PubMed1992

Peripheral MR angiography with variable velocity encoding. Work in progress.

An electrocardiographically triggered two-dimensional phase-contrast (PC) magnetic resonance angiographic pulse sequence was developed in which velocity encoding (VENC) was varied throughout an acquisition in response to changes in blood velocity during the cardiac cycle. This was done to better capture signal in the peripheral vasculature, where pulsatile flow degrades images. After reconstruction, a matched filter addition technique was applied to the cardiac phase images to obtain a single high-quality static image. Images were obtained of six healthy volunteers--with and without varying VENC--and contrast-to-noise ratio (C/N) calculations were performed for the added images. Varying VENC significantly improved vascular signal from small and large vessels (P less than .02), but it was most helpful for small vessels, for which the C/N increased by as much as 260% (average increase, 149%). These preliminary findings suggest that variable VENC can enhance the signal from the small and large peripheral blood vessels in cardiac-gated PC acquisitions.

Angiography↗
PubMed2004

Basics of intravascular ultrasound: an essential tool for the endovascular surgeon.

The concept of catheter-based ultrasound imaging was first introduced in the early 1970s. Since its inception, intravascular ultrasound (IVUS) technology has become more user-friendly because of improvements in both the catheters and computer-driven imaging platforms. IVUS catheters enable luminal and transmural cross-sectional imaging of coronary and peripheral blood vessels with high-dimensional accuracy and detailed information about lesion morphology. With the advent of endovascular techniques in both the coronary and peripheral vasculature, IVUS has emerged as a useful and necessary adjunct. In addition to providing diagnostic information, IVUS enables optimal choice of appropriate angioplasty technique, endovascular device guidance, and controlled assessment of the efficacy of interventions. In this review we discuss the design and function of available IVUS catheters, imaging techniques and interpretation, and the present and future clinical utility in peripheral endovascular interventions.

Forecasting↗
PubMedDate not supplied

[The capillaroscopy method and possibilities of its clinical use].

The aim of this paper is to point out the purpose and possibilities of practical application of capillaroscopy in the peripheral blood vessel alterations diagnosis and follow-up. The paper gives a detailed technical description of the method as well as the capillaroscopic findings interpretation criteria. A special attention has been paid to the most important external factors as well as to the diseases that may affect the peripheral blood flow condition.

Capillaries↗
PubMed1992

Effect of flunarizine on micro-regional distributions of intravascular HbO2 saturations in RIF-1 and KHT sarcomas.

Flunarizine, a calcium channel-blocker, preferentially active on peripheral blood vessels and red blood cells, has previously been shown to increase not only tumor blood flow, but also both chemosensitivity and radiosensitivity. The mechanisms behind these effects are not clear at present, and different tumor lines have been demonstrated to respond quite differently to the same flunarizine treatment. To clarify the underlying mechanisms at the micro-regional level, the present investigation examined the effects of flunarizine on spatially-resolved distributions of intravascular oxyhemoglobin (HbO2) saturations. Tumors were implanted s.c. in the flanks of C3H mice and grown to a volume of 500-1000 mm3. Flunarizine was injected i.p. at 5 mg/kg; animals were anesthetized, and following a 20 min delay, tumors were quick-frozen. HbO2 saturations were determined cryospectrophotometrically at systematically selected sites across each tumor cross-section. Three primary questions were addressed: (a) Does flunarizine have a direct effect on tumor oxygen delivery as measured by intravascular HbO2 saturations? (b) Are changes in oxygen delivery uniformly distributed throughout the tumor volume? (c) Are HbO2 distributions for tumor lines of dissimilar radiobiological hypoxic fraction affected similarly by flunarizine? For KHT tumors, flunarizine substantially increased the % vessels greater than or equal to 10% saturated throughout the tumor volume, with a somewhat larger increase for the interior vessels than for the peripheral vessels. In contrast, for the RIF-1 tumors, HbO2 saturations following flunarizine remained near control levels. These results indicate that fundamental differences in vascular geometry, hemodynamics, or blood rheology may exist between the KHT and RIF-1 tumor lines, and furthermore, that the response of one tumor line to a given blood-flow modifier may be completely unrelated to that of another.

Animals↗
PubMed1985

Modification of the vasoconstrictor effects of noradrenaline and serotonin by the selective calcium antagonist PY 108-068 in the peripheral circulation of anesthetized cats.

The effects of a noradrenaline (NA, 1 microgram/kg min) or serotonin (5-HT, 10 micrograms/kg min) infusion on regional blood flow and conductance were assessed with tracer microspheres before and after administration of the calcium-antagonist PY 108-068 (PY; 30 micrograms/kg). Chloralose-urethane-anesthetized cats were pretreated with propranolol 1 mg/kg i.v. or chlorisondamine 1 mg/kg i.v. for the experiments with NA or 5-HT, respectively. PY attenuated the NA-induced increase of blood pressure and the decrease of total peripheral conductance. The NA-induced vasoconstriction, occurring mainly in the kidneys, adrenals, liver, spleen, and arteriovenous shunts, was significantly attenuated by PY. The vessels of heart, stomach, pancreas, and skeletal muscle were not constricted by NA. In contrast, 5-HT dilated or tended to dilate almost all vascular beds examined. Only arteriovenous shunts were constricted. PY did not antagonize this vasoconstrictor effect. Moreover, after but not before PY treatment, a coronary vasoconstrictor effect of 5-HT was seen. Antivasoconstrictor effects of PY were observed both in organs where dihydropyridines normally elicit vasodilatation and in organs where such compounds have no vasodilator effects in the absence of a vasoconstrictor infusion. The regional distribution of the antivasoconstrictor effects was different for each vasoconstrictor tested so far (angiotensin II, 5-HT, and NA). The sites of action of calcium antagonists in peripheral blood vessels appear to depend on the mechanism of activation operating at that site and at the time of the investigation.

Animals↗
PubMed2002

Disseminated single tumor cells as detected by real-time quantitative polymerase chain reaction represent a prognostic factor in patients undergoing surgery for colorectal cancer.

OBJECTIVE: To evaluate the clinical relevance of real-time quantitative polymerase chain reaction (qPCR) detection of CEA and CK20 transcripts, as potentially related to tumor cell dissemination, in blood and peritoneal lavage from patients undergoing surgery for colorectal cancer. SUMMARY BACKGROUND DATA: Dissemination of single colorectal cancer cells in the peritoneal cavity, as well as in tumor drainage and peripheral blood vessels, might play a role in the metastasis process, thus affecting the clinical course. However, this phenomenon needs further elucidation. METHODS: In a prospective study the authors evaluated the potential of qPCR in the detection of CEA and/or CK20 transcripts in the peritoneal lavage fluid and in the peripheral and mesenteric venous blood of 39 patients undergoing curative resection for colorectal cancer. Peritoneal lavage and peripheral blood was sampled before and after tumor resection; mesenteric venous blood was sampled from the major tumor-draining vein immediately before clamping. After RNA extraction and reverse transcription, qPCR was performed using specific cDNA primers and probes for CEA and CK20. The dichotomous results from the qPCR were used as a predictor along with other covariates in Cox proportional hazard regression models of long-term outcome (disease-free survival and overall survival). RESULTS: Of 39 patients, 11 were positive. The median follow-up at analysis was 31 months for all patients. The dichotomous qPCR covariate was significant, with P =.001 and.0035 for disease-free survival and overall survival, respectively, in the proportional hazard regression models with only qPCR. In seven patients, disseminated colorectal cancer cells were found in the peritoneal lavage fluid but not in blood specimens; five of these patients (71%) had recurrence. CONCLUSIONS: These data suggest that detection of mRNA coding for CEA and/or CK20 using qPCR has potential clinical utility as a prognostic marker and should be evaluated in larger clinical studies. Identification of patients at high risk for metastatic disease after curative resection of colorectal cancer might be improved by analyzing peritoneal lavage specimens in addition to blood samples. This is based on the observation that in more than half of qPCR-positive patients, disseminated colorectal cancer cells were detected in peritoneal lavage specimens but not in blood samples, and that 71% of them had recurrence.

Adult↗
PubMed1992

[Diabetic retinopathy and other complications of diabetes mellitus].

The paper reviews the results of a ten-year follow up conducted in 140 diabetic patients at the Ophthalmology Clinic in Novi Sad. We analysed the number of the cases and ratios between diabetic retinopathy and other complications in eyes and other organs. Apart from retinopathy among eye diseases the most frequent was hypertonic fundus in 20%, cataract in 17% of the eyes and occlusive conditions in the retinal blood vessels in 2.6%. In the whole group only 8% of the examined eyes had no changes. Complications develop in 70% of diabetics with retinopathy and 48% of those without retinopathy. Nephropathy was found in 18% of diabetics with retinopathy and 13% of those without it. Macroangiopathy of the brain, heart and peripheral blood vessels was found in lower percentage but more frequently in diabetics with retinopathy.

Adult↗
PubMed1980

GABA receptors in bovine cerebral blood vessels: binding studies with [3H]muscimol.

[3H]Muscimol, a potent GABA agonist used to label GABA receptor sites in brain and invertebrate striated muscle, was found to bind specifically to sites in a crude membrane fraction prepared from bovine cerebral blood vessels. Specific [3H]muscimol binding was saturable of high affinity (Kd = 41 nM), and was selectively inhibited by GABA, specific GABA agonists, and the antagonist bicuculline with potencies similar to what has been found for GABA receptors in mammalian brain. GABA and several GABA agonists including muscimol have been reported to dilate isolated cerebral arteries, but not peripheral blood vessels. The pharmacology of the [3H]muscimol binding site correlated well with that of the vasodilatory response. No significant specific [3H]muscimol binding was detected in aorta and mesenteric arteries. The characteristics of the cerebrovascular muscimol binding site thus are indicative of a physiologically relevant GABA receptor associated with cerebral blood vessels. These findings suggest a direct role for GABA in cerebral vascular function.

Animals↗
PubMed1987

Cardiovascular effects of serotonin.

The major target for circulating serotonin (released from aggregating platelets) appears to be the blood vessel wall (although little evidence is available), suggesting a role for the monoamine in controlling cardiac function. In cerebral blood vessels, serotonergic neurons are present, implying a potential serotonergic neurogenic control. Serotonin causes contraction of most large arteries and veins; it also causes contraction of venules. This is due mainly to direct activation of vascular smooth muscle, although amplification of the response to other endogenous vasoconstrictors (e.g., angiotensin II and norepinephrine) as well as facilitated release of norepinephrine may contribute. In peripheral blood vessels, the receptors mediating the contractions evoked by serotonin belong mainly to the 5-HT2-serotonergic subtype; in the coronary and cerebral arteries, this need not be the case. Vasodilator responses to serotonin are seen mainly at the arteriolar level, but they can also be observed in larger blood vessels. They can be caused by the release of other endogenous vasodilators (e.g., vasoactive intestinal polypeptide), direct relaxation of vascular smooth muscle, inhibition of adrenergic neurotransmission, or production of endothelium-derived relaxing factor(s). The dilator responses to serotonin are mediated by receptors with characteristics similar to 5-HT1-serotonergic binding sites. Aggregating platelets release enough serotonin to evoke both constrictor and dilator responses. The absence of endothelium may change the primary response to aggregating platelets from relaxation to contraction. The responsiveness of the blood vessel wall to serotonin can be augmented acutely by local hypoxia or by cooling. It is exaggerated in blood vessels taken from hypertensive or atherosclerotic animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1980

Cardiovascular effect of "peritoneal dialysate-depressor-I", a short-active hypotensive phospholipid in dog peritoneal dialysate.

Cardiovascular action of "peritoneal dialysate-depressor-I" (PD.D-I), a short-acting hypotensive phospholipid occurring in dog peritoneal dialysate, was investigated. With an intravenous injection of PD.D-I into an anaesthetized rat, a sharp fall of arterial blood pressure was observed and the effects were dose dependent. The maximum hypotensive effect was about 60 mmHg and the minimum effective dose was approximately 35 micrograms/kg. Neither tachyphylaxis nor sensitization was observed. Even in conscious rats PD.D-I elicited hypotensive responses, though the effect was much weaker than that produced in anaesthetized rats. In spinal rats the hypotensive effects were also observed. In the tests on rats reserpinized or pretreated with antimuscarinic, antihistaminic, beta-adrenergic-blocking and ganglionic-blocking agents, the depressor effect of PD.D-I was not affected. PD.D-I elicited also hypotensive responses in anaesthetized cats, rabbits and guinea pigs in the same degree as those in anaesthetized rats. The relaxation of the peripheral blood vessels was observed in the test on perfused rabbit ear. The depressor factor showed no smooth muscle stimulating activity in isolated guinea pig ileum preparations. Judging from these findings, the hypotensive effect of PD.D-I is not ascribable to the central, sympathetic or parasympathetic nervous system but possibly to direct action on the peripheral vascular system.

Animals↗
PubMed1987

Reflex regulation of the circulation after stimulation of cardiac receptors by prostaglandins.

Prostaglandins (PGs) are potent vasoactive substances that may participate in the control of coronary blood flow, platelet aggregation, and inflammation. An important action of PGs may be the stimulation of c fibers in general and vagal cardiac c fibers in particular. The Bezold-Jarisch reflex after intracoronary injection of Veratrum alkaloids is very similar to the vagal bradycardia elicited by stimulation of cardiac PG synthesis or injection of prostacyclin (PGI2). The characteristic features of this reflex are 1) stimulation of c fibers, 2) inferoposterior wall location of receptors, 3) vagal afferents, 4) vagal efferents to the heart, 5) sympathetic efferents to peripheral blood vessels, and 6) interaction with other reflexes. Vagal cardiac c fibers are activated by intracoronary injections of PGI2 or arachidonic acid, resulting in a vagal reflex bradycardia and hypotension due to withdrawal of peripheral alpha-adrenergic tone to resistance vessels. The cardiac receptors are located predominantly in the inferoposterior wall of the left ventricle. When stimulated by PGs, cardiac receptors may also modify the regulation of arterial pressure by the baroreflexes, altering the inverse relationship between systemic arterial pressure and heart rate. Thus, there is a striking parallelism between the veratridine-induced Bezold-Jarisch reflex and PG-induced cardiac reflexes, although the physiological and clinical significance of these reflexes remains to be determined.

Animals↗
PubMed1975

Problems with bovine heterografts for hemodialysis. Recognition, correction, and prevention.

1. Careful examination of the peripheral blood vessels is essential in choosing the site for an arteriovenous heterograft. 2. Ischemia of the hand or fingers was avoided by placing upper extremity grafts in the forearm. 3. In the lower extremity, if peripheral pulses are normal, a straight thigh graft is preferred. 4. The recipient vien in the antecubital fossa should be no less than 4 mm in diameter; in the lower extremity the venous anastomosis should be made to the common femoral vein. 5. "Graft hypertension" is a sign of inadequate venous runoff and should be corrected before false aneurysms develop or occlusion of the graft occurs. 6. Most thrombosed grafts can be reopened and should be explored promptly through an incision near the venous end.

Animals↗
PubMed1994

[The effects of the cyclopentyl ethinyl estriol on the cardiovascular function of postmenopausal women].

The cardiovascular function of postmenopausal women before and after oral supplement of cyclopentyl ethinyl estriol (CEE3) were evaluated with 3-dimensional ultrasound and Doppler technique. The results are as follows: there were no changes of HR, SBP, DBP, MBP and E2 in postmenopausal women before and after the oral supplement of CEE3. Ves and SVR were obviously reduced (P < 0.001). SV, CO, EF, Vmax V and A were obviously increased (P < 0.001). There were no changes in Ved, E and E/A. The results showed that CEE3 could reinforce the cardiac function and increase cardiac output and also reduce the resistance in peripheral blood vessels in postmenopausal women. It is assumed that the cardioprotective effect of hormone replacement therapy in postmenopausal women may be due not only to changes in lipid profile but also to direct effects of estrogens on central and peripheral hemodynamic parameters.

Estrogen Replacement Therapy↗
PubMed1976

The role of noradrenaline and other transmitter hormones in the pathogenesis of hypertension.

1. Studies with a sensitive radioenzymatic assay for plasma noradrenaline suggest there is a selective overactivity of the sympathetic nerous system in essential hypertension. 2. Serotonin turnover in the mesenteric vessels is approximately twice that of noradrenaline and it is suggested that serotonin may interact with noradrenaline to maintain vascular resistance. 3. Methodology which allows the study of local sympathetic turnover in nuclei of the central nerous system and in peripheral blood vessels is decribed. This approach has been used to study non-innervated sympathetic turnover observed in phaceochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1977

Studies of neurotransmitter release in the pathogenesis of hypertension.

Studies using a sensitive radioenzymatic assay for plasma noradrenaline suggest there is a selective overactivity of the sympathetic nervous system in essential hypertension. Methodology which allows the study of local sympathetic turnover in CNS nuclei and peripheral blood vessels is described. This approach has been used to study the non-innervated sympathetic turnover phaeochromocytoma. It is suggested that studies of local regulatory mechanism in neurotransmitter release are required to give a greater understanding of the central and peripheral role of the sympathetic nervous system in the pathogenesis of hypertension.

Adrenal Gland Neoplasms↗
PubMed1997

Effects of carbogen plus fractionated irradiation on KHT tumor oxygenation.

BACKGROUND AND PURPOSE: Numerous studies have demonstrated improvements in the oxygenation of tumor cells following both irradiation and carbogen breathing. The current studies were initiated to measure the combined effects of carbogen inhalation plus single and multi-dose irradiation on tumor oxygen availability, to better define the underlying physiological relationships. MATERIALS AND METHODS: Using KHT murine sarcomas, radiation was delivered to the tumor-bearing legs of non-anesthetized mice. Tumors were quick-frozen prior to or following single or multifraction irradiation and carbogen breathing, and intravascular HbO2 saturation profiles were determined cryospectrophotometrically. RESULTS: HbO2 levels for blood vessels located near the tumor surface initially decreased following 10 Gy irradiation, then increased and remained elevated. Interior HbO2 levels remained unchanged. Following 2.5 Gy, HbO2 changes were minimal. At 24 h following 10 Gy, HbO2 levels were significantly increased compared to non-irradiated controls, and carbogen breathing produced no additional benefit. At 24 h following five fractions of 2 Gy, HbO2 levels throughout the tumor volume were significantly higher in carbogen breathing animals than in air breathing controls. CONCLUSIONS: Although peripheral blood vessels demonstrated substantial improvements in oxygenation following irradiation, oxygen availability nearer the tumor center remained at very low levels. The utility of carbogen in enhancing tumor oxygen availability was maintained following five clinically relevant fractions. At higher doses, radiation-induced enhancements in HbO2 levels overshadowed the carbogen effect. For either air or carbogen breathing, a decrease in the percentage of vessels with very low oxygen content did not appear to be a major factor in the reoxygenation of the KHT tumor.

Animals↗