Drop In Blood Flow Research Articles

The Influence of Cannulation Technique on Blood Flow to the Brain in Rats Undergoing Cardiopulmonary Bypass: A Cautionary “Tail”

Recently, there has been an increase in the use of rat models of cardiopulmonary bypass (CPB) for research purposes. Much of this work has focused on cerebral injury associated with CPB. Many of these studies employ a peripheral cannulation approach, often utilizing the caudal artery and internal or external jugular vein. The aim of the present study was to establish whether there is any alteration in blood flow to the brain associated with the use of different cannulation routes. Twenty-four adult male Sprague Dawley rats were allocated to one of three study groups: Group 1- caudal artery return, Group 2 -open-chest aortic return, and Group 3- nonbypass control group. Colored microspheres were injected into all animals at four time points (postinduction, initiation of bypass, midbypass, and end bypass). After the termination of each experiment, the brains were excised, the tissue was digested, the microspheres were harvested, and the global blood flow to the brain was assessed using the reference flow method. There was a significant reduction in blood flow to the brain between both bypass groups and the control group. Additionally, cerebral blood flow was significantly lower in the caudal return group than in the aortic return group. There is a significant drop in blood flow to the brain associated with the initiation and continuation of CPB when compared to non-CPB controls. These results also confirm a considerable cerebral hypoperfusion associated with the peripheral cannulation technique, and suggest that peripheral bypass may exaggerate the influence CPB has on cerebral injury. This technique must therefore be employed with caution.

Effects of Highly Concentrated Artificial Carbonic Acid Forearm-Bathing on Core Temperature Cooling for Hyperthermia

PURPOSE: High temperature and high humidity make heat radiation inefficient, it is easy to suffer from hyperthermia during exercise. This study examined the effect of cooling by the highly concentrated artificial carbonic acid water at rest following exercise. METHODS: Subjects were nine male students who consented to participate in the present study. Subjects were not permitted to consume alcohol on the day before the test, engage in exercise on the day of the test, or eat during the 2 hours prior to the start of the test. After 60 min resting state in a controlled environment (room temperature, 29°C; relative humidity, 70%), they exercised by cycle ergometer at 75%HRmax for 20 minutes. Then the subjects were cooled using each of the following methods: immersion of both arms in highly concentrated artificial carbonic acid water (33°C), and immersion of both arms in tap water (33°C). The skin (forearm) and core (sub-lingual) temperatures and thermal sensation in the forearm and body were measured. RESULTS: The sum of core temperatures decreases to the experiment end, assuming the time of immersion start as standard, and was larger with the carbonic acid water (13.0 ± 0.99°C) than with the tap water (12.6 ± 1.89°C). However, there was no significant difference between the immersion trial comparisons. The skin temperature decreases with the carbonic acid water (1.55 ± 0.09°C) were significantly smaller than that with the tap water (1.91 ± 0.10°C). And at the time of immersion, each of the between immersion trial comparisons was significantly different in thermal sensation for the forearm. The subjects felt warmer with the carbonic acid water (5.94 ± 0.21) than that with the tap water (4.45 ± 0.18). CONCLUSION: The carbonic acid water was larger in the sum of the variation of decline of core temperature. These data indicated that carbonic acid attenuated skin vasoconstriction and suppressed the drop in blood flow compared to water. As a result carbonic acid decreased core temperature efficiently. These results suggest that forearm bathing in highly concentrated artificial carbonic acid might afford cooling efficiency without placing athletes under the burden of cold water stimulation.

Hemodynamic Mechanisms of Reduction of Venous Return and Pulmonary Circulation during Experimental Myocardial Ischemia

Ischemia of left ventricular myocardium in cats moderated blood flow in the venae cavae and decreased venous return, which leads to a drop of blood flow and blood pressure in the pulmonary artery. Shifts in the right atrial pressure had no effects on changes in venous returns. After elevation of the left atrial pressure, promoted by a decrease in contractility of the left ventricular myocardium, blood pressure in the pulmonary artery decreased to a lesser extent than pulmonary blood flow, but did not correlate with shifts in pulmonary vascular resistance.

Cosmic Implications of NXY-059

The SAINT studies on NXY-0591,2 have reinvigorated debate over the momentous issues of neuroprotection and the development of novel stroke therapeutics. Some may argue there is little new ground that NXY-059 has unearthed and, in fact, the clinical trials merely confirm that as a strategy, neuroprotection has not been shown to be effective. Editorials in high-profile journals have sent out the clarion call to terminate research on neuroprotection given decades of work, which has uniformly led to failure after failure in clinical studies.3 These sentiments are premature and ignore studies showing that hypothermia improves outcome in patients after cardiac arrest, a major cause of global cerebral ischemia.4,5 Proof for the neuroprotection concept has therefore already been established. Despite decades of neutral clinical trials, there still remains optimism among the stroke academic community. A majority of university-affiliated stroke neurologists in the United States in a recent survey still believe neuroprotection is a viable therapeutic strategy, although admittedly, that survey was conducted between the SAINT I and SAINT II publications.6 However, the question whether neuroprotection will ever work in stroke has been overshadowed by the larger issue of whether animal studies, which serve as the foundation for the development of stroke therapeutics, are even relevant to our patients with acute stroke. In the discussion section of the SAINT II article, the authors write, “it is possible that the animal models of acute focal infarction are not relevant to the patient population; they certainly are insufficient to guarantee a positive clinical-trial result.” Have all prior neuroprotective agents failed in clinical studies because rodent stroke is not relevant to human stroke? This is a key question. Substantial reductions in infarct size in rodents with stroke treated with various types of purported neuroprotective agents would seem to support this view. There …

Right Ventricular Assistance by Continuous Flow Device

This work is another step in the development of the circulatory model CARDIOSIM and of its model library. Continuous flow assistance is often used to support the right ventricular failure. Computer simulation is one of the methods to study the effect of this assistance on the failing ventricle. The purpose of this study was to evaluate the effect of this support on some hemodynamic variables, when different right ventricular end-systolic elastance and pump speed values were applied. The rotary blood pump model was included into the software package CARDIOSIM, which reproduces the cardiovascular system. Lumped parameters models were used to reproduce the circulatory phenomena. Variable elastance models reproduced the Starling's law of the heart for both ventricles. In the study right ventricular end-systolic elastance (EmaxRIGHT) and the rotational speed of the pump took three different values. All the other parameters of the model were constants. The rotational speed of the pump had a significant influence on right ventricular end-diastolic and end-systolic volumes, right atrial pressure (Pra), right ventricular (Qro) and pump flows. The effects on pulmonary arterial pressure (Pap) were more evident when the right ventricular end-systolic elastance was low. When the speed of the device increased the mean value of Pra decreased for each value of EmaxRIGHT. The total flow (Qro+pump flow) increased when the speed of the pump increased. Our simulation (in good agreement with the results presented in literature) showed that Hemopump produces a rise in total flow, a drop in blood flow pumped out by the right ventricle and a drop in right atrial pressure.

Hyperthermia Impairs Brain, Heart and Muscle Function in Exercising Humans

Marathon running poses a severe challenge to multiple regulatory systems and cellular homeostasis, especially when performed in hot environments without fluid replacement. During exercise in the heat, the ensuing dehydration causes hyperthermia and the synergistic effects of both stressors reduce cardiac output and blood flow to muscle, skin, brain and possibly splanchnic tissues. The drop in blood flow beyond the regulatory adjustment to concurrent increases in blood oxygen content leads to reductions in oxygen delivery, suppressed muscle aerobic energy turnover and greater reliance of the exercising muscles on anaerobic metabolism before fatigue. The accelerated hyperthermia-mediated fatigue during prolonged and maximal exercise is preceded by functional alterations in multiple bodily systems including the brain, heart and muscle. It is proposed that the impaired marathon running performance in warm environments is associated with a greater thermal, cardiovascular and metabolic strain, and perception of effort that prevents marathon runners from running at their personal record speed without inducing an accelerated regulatory dysfunction in multiple bodily systems.

Development of a new method for monitoring blood purification: The blood flow analysis of the head and foot by laser Doppler blood flowmeter during hemodialysis

The management of blood pressure in hemodialysis patients greatly affects not only their quality of life, but also the duration of dialysis (dialysis life). Approximately 25% of dialysis patients suffer from continuous low blood pressure; however, the relationship between blood pressure and blood flow during dialysis has not been established. We hypothesized that with complete extracorporeal circulation, blood purification methods might affect blood flow, resulting in a change in blood pressure. The purpose of this study was to develop a noninvasive continuous monitoring method (NICOMM) as a microcirculation monitor by devising a laser-Doppler flowmeter (LDF) system with a wavelength of 780 nm. The aim was to use this system to simultaneously measure blood flow rate in both the head and the foot during dialysis and to determine the effectiveness of NICOMM by measuring blood flow and arterial distensibility. When exhibiting a significant decline in blood pressure at 240 min after the initiation of hemodialysis, a drop in blood flow in parallel with the blood pressure fall was recorded by the LDF. However, no changes were observed, in the readings by a continuous hematocrit monitor (Crit-Line monitor, CLM). Furthermore, a significant correlation was registered between mean arterial blood pressure and blood flow rate in the earlobe tissue from 180 min after the initiation of hemodialysis to the completion of hemodialysis (p < 0.001, r = 0.78). Comparisons were made by measuring vascular dehydration using the CLM. NICOMM showed more stable readings than the CLM in monitoring blood flow in response to changes in blood pressure.

Decreased Porcine Uterine Blood Flow During Laparoscopic Nissen Fundoplication

Background: Laparoscopy produces significant hemodynamic alterations that could affect blood flow through various systems, such as the cerebral, splanchnic, and renal circulations. While laparoscopic surgery is indicated for obstetrical and non-obstetrical conditions in pregnant patients, the effect of laparoscopy on uterine blood flow has hitherto been unclear. This experiment measures uterine blood flow in pigs undergoing laparoscopic Nissen fundoplication using radioactive microspheres. Methods: Six (6) pigs were subjected to a standard laparoscopic Nissen fundoplication. Microspheres (15 µm) labeled with five different radioisotopes were injected directly into the left ventricle at five different stages of the procedure. After the procedure, the pigs were euthanized and the uterus of the pig was harvested to measure blood flow. Results: There was a decrease in uterine blood flow at all stages of the procedure, with a statistically significant maximal drop in blood flow of –82%. These changes were associated with a simultaneous increase in paCO2 in all stages from baseline excepting the last time-point. Conclusions: Laparoscopy produces significant alterations in uterine blood flow. These changes can have profound effects on the fetus and maternal wellbeing by possibly worsening fetal acidosis. (J GYNECOL SURG 20:113)

The Physiological Effect of DE QI during Acupuncture

Acupoints tend to show higher electric conductivity and have a higher concentration of neural and vascular elements as well as mast cells. According to one model, the meridian is an extravascular fluid (interstitial fluid) pathway and circulation of this fluid is driven by skeletal muscle contraction. Our result derived from laser Doppler flowmetry shows that Yanglao (SI6) and Xiaohai (SI8) have larger amplitude of heartbeat and vasomotion than non-acupuncture points. The amplitude of blood flow on the SI8 shows a more significant increase (4.3 ± 0.7 PU) than that of non-acupuncture points (1.1 ± 0.2 PU). Our results indicate that acupuncture increases blood flow when the De-Qi sensation takes place. In the experiment, the needle was only entered into the subject by 2 mm for about 15 sec during a SI6 acupuncture session, and the blood flow increased immediately. The blood flow of SI8 began to rise 5 sec after implementation and increased by 11.1 ± 0.9 PU. However, when the arm was tied up, the blood flow at the SI8 point slowed down quickly. Even though insertion with a twirling needle was followed after the drop in blood flow, the blood flow at the SI8 point did not accelerate again (0.7 ± 0.2 PU). The present study seems to show that acupuncture is effective in regulating the autonomic nervous system. Implementation of acupuncture causes the sphincter of microvessel to relax, and the tissue fluid to flow out, and the propagated sensation along the meridian is caused by this large amount of tissue fluid that flows along the loosen body stalk. The interstitial fluid increases during the needling and blood capillary expansion, which may be one of the mechanisms of acupuncture regulation.

Coronary smooth muscle reactivity to muscarinic stimulation after ischemia-reperfusion in porcine myocardial infarction.

This study tested whether ischemia-reperfusion alters coronary smooth muscle reactivity to vasoconstrictor stimuli such as those elicited by an adventitial stimulation with methacholine. In vitro studies were performed to assess the reactivity of endothelium-denuded infarct-related coronary arteries to methacholine (n = 18). In addition, the vasoconstrictor effects of adventitial application of methacholine to left anterior descending (LAD) coronary artery was assessed in vivo in pigs submitted to 2 h of LAD occlusion followed by reperfusion (n = 12), LAD deendothelization (n = 11), or a sham operation (n = 6). Endothelial-dependent vasodilator capacity of infarct-related LAD was assessed by intracoronary injection of bradykinin (n = 13). In vitro, smooth muscle reactivity to methacholine was unaffected by ischemia-reperfusion. In vivo, baseline methacholine administration induced a transient and reversible drop in coronary blood flow (9.6 +/- 4.6 to 1.9 +/- 2.6 ml/min, P < 0.01), accompanied by severe left ventricular dysfunction. After ischemia-reperfusion, methacholine induced a prolonged and severe coronary blood flow drop (9.7 +/- 7.0 to 3.4 +/- 3.9 ml/min), with a significant delay in recovery (P < 0.001). Endothelial denudation mimics in part the effects of methacholine after ischemia-reperfusion, and intracoronary bradykinin confirmed the existence of endothelial dysfunction. Infarct-related epicardial coronary artery shows a delayed recovery after vasoconstrictor stimuli, because of appropriate smooth muscle reactivity and impairment of endothelial-dependent vasodilator capacity.

Role of K+ATP channels, endothelin A receptors, and effect of angiotensin II on blood flow in oral tissues.

K+(ATP) channels are involved in CGRP-mediated vasodilation and in the vasoconstriction induced by endothelin or angiotensin II. In this study, we examined the effects of a K+(ATP) channel antagonist and an ET(A) receptor antagonist on resting blood flow in the pulp and gingiva, and observed their role in the vasodilation induced by tooth stimulation. We also investigated whether receptors for angiotensin II exist in the pulp and gingiva. Blood flow was measured with laser-Doppler flowmetry. Under control conditions, the K+(ATP) channel antagonist and angiotensin II caused a significant drop in blood flow in both target tissues. Blocking of ET(A) receptor did not change basal blood flow. The vasodilation observed after tooth stimulation remained unchanged following blockade of K+(ATP) channels and ET(A) receptors. Analysis of the data shows that open K+(ATP) channels exist during resting conditions in the pulp and gingiva, but that CGRP seems to induce vasodilation mainly via mechanisms other than K+(ATP) channels. ET(A) and AT(1) receptors are found in the pulp and gingiva, but ET(A) receptors are not involved in modulation of a basal vascular tone in these tissues or in the vasodilation observed after tooth stimulation.

Neurochemical changes and laser Doppler flowmetry in the endothelin-1 rat model for focal cerebral ischemia

Generalized neurotransmitter overflow into the extracellular space, after cerebral ischemia, has been suggested to contribute to subsequent neuronal death. This study aims to investigate the striatal release of the neurotransmitters dopamine (DA), glutamate (Glu) and gamma-aminobutyric acid (GABA) by means of microdialysis, in a rat model for focal transient cerebral ischemia. Ischemia was induced by the application of 120 pmol endothelin-1 (Et-1), adjacent to the middle cerebral artery (MCA) in freely moving rats. Ischemia produced a large increase in extracellular striatal DA concentrations (2400%), Glu (5500%) and GABA (800%) concentrations. Laser Doppler flowmetry in anaesthetized rats, indicated that the blood flow within the striatum decreased by 75±11%. The period of sustained drop of blood flow, was dose-dependently related to the concentration Et-1 injected. Histological analysis of brain slices, taken from anaesthetized and conscious animals, indicated a 500 pmol dose of Et-1 was required to produce a similar infarct in anaesthetized rats to a 120 pmol dose of Et-1 in freely moving rats. The immediate drop in striatal blood flow, and the prompt increase of extracellular DA, after the micro-application of Et-1, were quite striking. This suggests that the DA release, rather than the Glu overflow may be the primary event initiating the cascade of processes ultimately leading to cell death and neurological deficits.

Changes in graft flow pattern from the descending aorta due to intraaortic balloon pump

During surgery for lung cancer in a patient who had undergone coronary artery bypass grafting through the descending aorta by left thoracotomy, we measured graft bypass blood flow from the descending aorta under intraaortic pump (IABP) assistance. Under IABP assistance, the diastolic waveform changed to a spiky pattern with a sharp drop in blood flow of approximately 16% compared to that without IABP assistance. We report changes in graft flow pattern during IABP assistance when the graft is placed from the descending aorta.

Outpatient High-Dose Urokinase Infusion Improves Dialysis Catheter Longevity: A Prospective Observational Study

Catheter thrombosis is a major limiting factor affecting catheter survival in hemodialysis (HD). A previous retrospective study highlighted the utility of outpatient intradialytic high-dose urokinase (HDU) infusion in the treatment of HD catheter thrombosis. The present study was designed to prospectively evaluate the effectiveness of 250 000 IU urokinase given as a 3-hour infusion during HD. The infusion would follow detection of a drop in blood flow thought to be secondary to thrombosis [a "thrombotic event" (TE)] after exclusion of nonthrombotic causes of drop in blood flow [a "nonthrombotic event" (NTE)], such as systemic hypotension or suboptimal position of the catheter on x ray. An “event” was defined as a drop in pump blood flow by greater than or equal to 20% of the prescribed blood flow. Twenty patients (mean age 57.7 years; 13 males) with documented or potentially long-term catheters were recruited (total catheters used, 30) from an outpatient HD unit. A variety of catheter types were used. Catheter position was confirmed on x ray. Hemodialysis sessions were monitored for 6 months or until catheter removal (whichever was earlier). Thrombotic and NTEs (mostly related to drop in blood flow) were noted. The use of intradialytic HDU infusions was monitored. Improvement was defined as reestablishment of blood flow to within 10% of prescription. There were 24 TEs in 11 patients and 15 NTEs in 7 patients. Twenty-one of 22 (95%) TEs responded to HDU, with complete restoration of blood flow; in 1/22 HDU-treated instances there was a partial response. For 2/24 TEs the patients underwent catheter stripping with good results. Twelve of 15 NTEs occurred in the first 2 weeks of catheter placement versus 6/24 TEs (p = 0.001, chi-square). Catheter survival was longer than 24 weeks in 12/30 catheters. Nine catheters were lost to NTEs. No catheter was lost secondary to a TE. It is therefore concluded that intradialytic outpatient HDU is useful for the treatment of HD catheter thrombosis. It may obviate/reduce the need for catheter stripping or replacement. Randomized controlled trials with this approach are needed. A higher proportion of NTEs tended to occur earlier after catheter placement compared to TEs.

Outpatient High-Dose Urokinase Infusion Improves Dialysis Catheter Longevity: A Prospective Observational Study.

Catheter thrombosis is a major limiting factor affecting catheter survival in hemodialysis (HD). A previous retrospective study highlighted the utility of outpatient intradialytic high-dose urokinase (HDU) infusion in the treatment of HD catheter thrombosis. The present study was designed to prospectively evaluate the effectiveness of 250 000 IU urokinase given as a 3-hour infusion during HD. The infusion would follow detection of a drop in blood flow thought to be secondary to thrombosis [a "thrombotic event" (TE)] after exclusion of nonthrombotic causes of drop in blood flow [a "nonthrombotic event" (NTE)], such as systemic hypotension or suboptimal position of the catheter on x ray. An "event" was defined as a drop in pump blood flow by greater than or equal to 20% of the prescribed blood flow. Twenty patients (mean age 57.7 years; 13 males) with documented or potentially long-term catheters were recruited (total catheters used, 30) from an outpatient HD unit. A variety of catheter types were used. Catheter position was confirmed on x ray. Hemodialysis sessions were monitored for 6 months or until catheter removal (whichever was earlier). Thrombotic and NTEs (mostly related to drop in blood flow) were noted. The use of intradialytic HDU infusions was monitored. Improvement was defined as reestablishment of blood flow to within 10% of prescription. There were 24 TEs in 11 patients and 15 NTEs in 7 patients. Twenty-one of 22 (95%) TEs responded to HDU, with complete restoration of blood flow; in 1/22 HDU-treated instances there was a partial response. For 2/24 TEs the patients underwent catheter stripping with good results. Twelve of 15 NTEs occurred in the first 2 weeks of catheter placement versus 6/24 TEs (p = 0.001, chi-square). Catheter survival was longer than 24 weeks in 12/30 catheters. Nine catheters were lost to NTEs. No catheter was lost secondary to a TE. It is therefore concluded that intradialytic outpatient HDU is useful for the treatment of HD catheter thrombosis. It may obviate/reduce the need for catheter stripping or replacement. Randomized controlled trials with this approach are needed. A higher proportion of NTEs tended to occur earlier after catheter placement compared to TEs.

Effects of systemic hypothermia and selective brain cooling on ischemic brain damage and swelling.

The present study investigates the neuroprotective effects of temporary mild systemic hypothermia and selective brain cooling against focal cerebral infarction in the rat and the changes of cortical blood flow, and compares these two treatment modalities. In permanent middle cerebral artery (MCA) model, the treatments were induced 15 min following the artery occlusion. The animals were kept at the desired rectal or brain temperature (about 32 degrees C) for 30 min; (each, n = 6) and for 1 hr (each, n = 6), and then allowed to rewarm spontaneously, whereas control animals were kept at normothermia throughout the experiment. The volumes of brain infarction and edema were assessed 24 hr post-occlusion. The blood flow of the dorsolateral cortex was monitored by Laser-Doppler flowmetry (LDF) in the other experiments. Hemispheric infarct volume was attenuated only in the animals treated for 1 hr with systemic hypothermia (49.2%, P < 0.001) and selective brain cooling (26.7%, P < 0.01). The volume of brain swelling was diminished only in the animals treated with systemic hypothermia for 1 hr (23.6%, P < 0.05). LDF examination revealed a sharp drop in blood flow upon MCA occlusion and maintaining in low blood flow throughout the experiment in the control and systemic hypothermia. However, in the selective brain cooling, the reduced blood flow increased from 40% to 70% of baseline value while the brain was rewarmed. The present study indicates that mild systemic hypothermia has much stronger protective effects against focal cerebral infarction and edema than selective brain cooling. The lack of protective effects of selective brain cooling may be caused by post-cooling cerebral hyperemia in the ischemia area.

Response of the middle cerebral artery to serotonin

The effect of serotonin on blood flow in the middle cerebral and common carotid arteries was studied with the help of Doppler ultrasonography on Wistar rats under general anesthesia. Serotonin induced a constrictor-dilator reaction in the middle cerebral artery: in 50% of experiments a marked initial blood flow drop was followed by a moderate increase, and then again by a profound and long decrease of the blood flow. At the same time the blood flow augmented in the common carotid artery. The data show selective and mostly vasoconstrictor effect of serotonin of the middle cerebral artery system.

Neurally mediated negative inotropic effect impairs myocardial function during cholinergic coronary vasoconstriction in pigs.

Myocardial dysfunction elicited during cholinergic coronary vasospasm is generally ascribed to myocardial ischemia. However, when pericoronary nerves extend to the ventricles, efferent vagal discharges that elicit coronary vasoconstriction may, at the same time, depress myocardial contractility by releasing acetylcholine into the myocardium. We analyzed whether a neurally mediated effect contributes to impairment of ventricular function during cholinergic coronary vasoconstriction. Left ventricular (LV) function, ECG mapping, and coronary angiography were analyzed during pericoronary application of methacholine (MCh) to the left anteriors. descending coronary artery in 53 chloralose-anesthetized openchest pigs. MCh induced local coronary vasoconstriction and depressed coronary blood flow (13.3 +/- 3.7 to 6.0 +/- 4.6 mL/min [54%]; ANOVA, P < .001), systolic LV pressure (105 +/- 10 to 91 +/- 10 mm Hg [13%], P < .001), peak LV (+)dP/dt (2890 +/- 524 to 2270 +/- 447 mm Hg/s [21%], P < .001), peak LV (-)dP/dt (1446 +/- 484 to 1048 +/- 276 mm Hg/s [27%], P < .001), and regional systolic segment shortening (0.32 +/- 0.09% to 0.18 +/- 0.14% [43%], P = .02) and caused local ST-segment elevation (0.9 +/- 0.8 to 8.4 +/- 3.9 mV, P < .001). These changes were not preceded by heart rate variations, were reproducible, and were inhibited by atropine. MCh during perfusion of nitroglycerin (2 micrograms.kg-1.min-1 IV) continued to depress LV pressure (9%, P = .002), LV (+)dP/dt (16%, P < .01), LV (-)dP/dt (20%, P < .01), and segment shortening (18%, P = .03) even though coronary blood flow drop was markedly attenuated (7% versus 54%; ANOVA, P < .01). Disruption of pericoronary nerves with phenol attenuated MCh-induced LV pressure fall (P < .05). Histological data show that cholinergic and adrenergic pericoronary nerves extend into the ventricular myocardium. A neurally mediated effect, in addition to ischemia, impairs LV function during cholinergic coronary constriction in a model with pericoronary nerves extending into the ventricles.

Decreases in postural change of finger blood flow in ceramic painters chronically exposed to low level lead

To elucidate the effect of low level lead (Pb) exposure on somatic and automatic peripheral nerve functions in ceramic painters, 58 males and 70 females, aged 29–75 years (mean 53.3 years), with lead concentrations in blood (Pb-B) ranging from 2.1 to 69.5 μg/dl (geometric mean 13.3 μg/dl), were examined for median nerve maximal conduction velocity as a measure of motor nerve function, the coefficient of variation of R-R interval on electrocardiography as a measure of parasympathetic function, and postural changes in finger blood flow volume (ΔFBF), and changes in finger blood flow drop velocity (FDV) from the supine to standing position as a measure of sympathetic function. No significant association was found between Pb-B levels and the results of the neurophysiological tests, however, except for that between Pb-B and ΔFBF. ΔFBF was decreased linearly with increasing Pb-B levels. However, this association could not be concluded to be a reflection of sympathetic nerve dysfunction due to Pb exposure in the subjects, since ΔFBF was not a specific parameter of sympathetic nerve function. The possibility that the decrease in ΔFBF is a reflection of the atherosclerotic effect of chronic low level Pb exposure should be further investigated. © 1996 Wiley-Liss, Inc.

Decreases in postural change in finger blood flow in ceramic painters chronically exposed to low level lead.

To elucidate the effect of low level lead (Pb) exposure on somatic and autonomic peripheral nerve functions in ceramic painters, 58 males and 70 females, aged 29-75 years (mean 53.3 years), with lead concentrations in blood (Pb-B) ranging from 2.1 to 69.5 micrograms/dl (geometric mean 13.3 micrograms/dl), were examined for median nerve maximal conduction velocity as a measure of motor nerve function, the coefficient of variation of R-R interval on electrocardiography as a measure of parasympathetic function, and postural changes in finger blood flow volume (delta FBF), and changes in finger blood flow drop velocity (FDV) from the supine to standing position as a measure of sympathetic function. No significant association was found between Pb-B levels and the results of the neurophysiological tests, however, except for that between Pb-B and delta FBF was decreased linearly with increasing Pb-B levels. However, this association could not be concluded to be a reflection of sympathetic nerve dysfunction due to Pb exposure in the subjects, since delta FBF was not a specific parameter of sympathetic nerve function. The possibility that the decrease in delta FBF is a reflection of the atherosclerotic effect of chronic low level Pb exposure should be further investigated.