What is the meaning of provoked spasm phenotypes by vasoreactivity testing?

Coronary artery epicardial spasm is involved in the pathogenesis of many cardiac disorders. Vasoreactivity testing, such as intracoronary injection of acetylcholine (ACH) or ergonovine (ER), is the gold standard method for the diagnosis of vasospastic angina. Provoked epicardial spasm phenotypes are classified as focal spasm and diffuse spasm. Multiple factors, including sex, ethnicity, and use of coronary vasoactive stimulators, are related to the provoked phenotypes of epicardial spasm. Diffuse-provoked spasm is often observed in females, where focal-provoked spasm is markedly more common in males. ACH provokes more diffuse and distal spasms, whereas ER induces more focal and proximal spasms. Yellow plaque and coronary thrombi are often observed in lesions with focal spasms, and intimal thickness with a sonolucent zone is significantly more common in lesions with focal spasm. Furthermore, clinical outcomes in patients with focal spasm are unsatisfactory compared with those in patients with diffuse spasm. However, the reproducibility and eternality of provoked spasm phenotypes by vasoreactivity testing is uncertain. Coronary atherosclerosis or endothelial damage may affect coronary vasomotor tone. Although coronary artery spasm may persist in the same coronary artery, provoked coronary spasm phenotypes may exhibit a momentary coronary reaction by intracoronary ACH or ER testing.

Omitting 50 μg of intracoronary acetylcholine injection in the left coronary artery during spasm provocation test

BACKGROUND

Although guidelines recommend intracoronary administration of acetylcholine (ACh) with incremental doses of 20, 50, and 100 μg into the left coronary artery (LCA) during spasm provocation test for diagnosing vasospastic angina, 50 μg of ACh rarely induced significant coronary vasospasm when no vasoconstriction was observed with 20 μg of ACh in a previous report. The aim of this study was to evaluate the safety and feasibility of omitting 50 μg according to the vasoreactivity by 20 μg of ACh in the LCA.

METHODS

A total of 556 patients undergoing ACh provocation test with 20 μg followed by 50 and/or 100 μg were retrospectively included. Injection of 50 μg of ACh was primarily omitted when vasoconstriction <25 % was observed with 20 μg, which was left to operator's discretion. Adverse events were defined as a composite of ventricular fibrillation, sustained ventricular tachycardia, and cardiogenic shock during ACh test in the LCA.

RESULTS

Positive ACh test in the LCA was observed in 245 (44.1 %) patients. Overall, patients with LCA constriction <25 % by 20 μg of ACh had a lower rate of positive ACh test than their counterpart (24.0 % vs. 88.4 %, p < 0.001). In patients with LCA constriction ≥25 % by 20 μg, the incidence of adverse events was significantly higher than in those with LCA constriction <25 % during the provocation test at doses of 50 and 100 μg (2.3 % vs. 0 %, p = 0.009).

CONCLUSIONS

Omitting 50 μg of ACh in the LCA may be safe and feasible when little vasoconstriction was observed with preceding injection of 20 μg of ACh during spasm provocation test for diagnosing vasospastic angina. However, we believe that 50 μg of ACh should not be omitted when 20 μg of ACh induced LCA constriction ≥25 %.

Safety and potential usefulness of sequential intracoronary acetylcholine and ergonovine administration for spasm provocation testing

BACKGROUND

Although guidelines recommend intracoronary acetylcholine (ACh) and ergonovine (ER) provocation testing for diagnosis of vasospastic angina, the feasibility and safety of sequential (combined) use of both pharmacological agents during the same catheterization session remain unclear.

OBJECTIVES

In this study, we investigated the feasibility and safety of sequential intracoronary ACh and ER administration for coronary spasm provocation testing.

METHODS

The study included 235 patients who showed positive results on ACh and ER provocation testing. Initial intracoronary ACh administration was followed by ER administration for left coronary artery (LCA) spasm provocation testing. Subsequently, the right coronary artery (RCA) was subjected to sequential ACh and ER administration for provocation testing. The primary outcome of the study was the safety of sequential intracoronary ACh and ER provocation testing, which was assessed based on a composite of all-cause death, sustained ventricular tachycardia and fibrillation, and cardiogenic shock.

RESULTS

Even in patients with negative results on sequential intracoronary ACh and ER provocation testing in the LCA and only ACh administration into the RCA, additional administration of ER into the RCA showed a positive provocation test result in 33 of 235 (14.0%) patients; three (1.3%) patients developed adverse effects (cardiogenic shock occurred in all cases) during LCA provocation testing. We observed no deaths attributable to spasm provocation testing.

CONCLUSION

Sequential administration of intracoronary ACh and ER was associated with a relatively low major complication rate and may be safe and potentially useful for diagnosis of vasospastic angina.

Gastroprotective and ulcer healing effects of Nauclea pobeguinii (Rubiaceae) on experimentally induced gastric ulcers in male Wistar rats

OBJECTIVES

In this study, we determined the gastroprotective and ulcer-healing effects of extracts (aqueous and methanolic) of Nauclea pobeguinii stem-back.

METHODS

Gastroprotective and healing activity were evaluated following a HCl/ethanol and an indomethacin-induced acute ulcers models; acetic acid, pylorus-ligature, pylorus ligature/histamine and pylorus ligature/acetylcholine-induced chronic ulcers models.

RESULTS

It emerges from this study that, at 100, 200 and 400 mg/kg, the extracts significantly reduced the various ulceration parameters. Compared to negative control male rats, the aqueous (100 mg/kg) and methanolic (400 mg/kg) extracts of Nauclea pobeguinii inhibited the ulcers induced by HCl/ethanol by 80.76 % and 100 % respectively, as well as ulcers induced by indomethacin by 88.28 % and 93.47 % respectively. Animals that received 200 mg/kg of both extracts showed a significant reduction in the levels of monocytes, lymphocytes, nitric oxide, MDA and a significant increase in the activities of SOD and catalase. Histological analysis showed repaired mucous epithelium at all doses of both extracts. Aqueous and methanol extracts inhibited ulceration indices by 89.33 % and 88.53 % for pylorus ligature, 83.81 % and 61.07 % for pylorus ligature/acetylcholine and 87.29 % and 99.63 % for pylorus ligature/histamine respectively. Both extracts protected the stomach lining with percentages inhibition of 79.49 % and 81.73 %, respectively in the ethanol test. The extracts induced a significant increase in mucus mass (p<0.001).

CONCLUSIONS

The aqueous and methanol extracts of Nauclea pobeguinii healed ulcers thanks to their anti-inflammatory, anti-oxidant, anti-secretory and cytoprotective properties.

J wave dynamicity during coronary angiography and intracoronary acetylcholine administration

BACKGROUND

J-waves may be observed during coronary angiography (CAG) or intracoronary acetylcholine (ACh) administration, but their significance is unknown.

METHODS

Forty-nine patients, 59.1 ± 11.5 years old and 59% male, were studied on suspicion of vasospastic angina, and J wave dynamicity was compared between CAG and Ach administration.

RESULTS

Diagnostic (≥0.1 mV) or nondiagnostic (<0.1 mV) J waves in 9 and 3 patients, respectively, were augmented, and J waves were newly observed in 2 patients during CAG and Ach administration. Similar changes in the J-wave amplitude were observed: from 0.10 ± 0.09 mV to 0.20 ± 0.15 mV (p < .002) and from 0.10 ± 0.10 mV to 0.20 ± 0.16 mV (p < .001) during CAG and Ach administration, respectively. J waves were located in the inferior leads and changed only during the right coronary interventions. In the remaining 35 patients, J waves were absent before and during the coronary interventions. Augmentation of J waves was found when the RR interval was shortened in some patients. Injection of anoxic media into the coronary artery might induce a conduction delay from myocardial ischemia that manifests as augmentation or new occurrence of J waves.

CONCLUSIONS

Both CAG and intracoronary Ach administration affected J waves similarly in the same individuals. A myocardial ischemia-induced conduction delay may be responsible for the changes in J waves, but further studies are needed.

Evaluation of Nootropic Potential of Aerva persica Roots against D-galactose-induced Memory Impairment

BACKGROUND

The primary phytoconstituents reported to have neuroprotective effects are flavonoids and phenolic compounds. Aerva persica roots are reported to be rich in flavonoids and phenolic compounds. Therefore, this study aimed to explore the nootropic potential of Aerva persica roots.

OBJECTIVE

The objective of this study was to evaluate the nootropic potential of Aerva persica roots against D-galactose-induced memory impairment.

METHODS

In this study, the roots of Aerva persica were extracted with 70% ethanol. The obtained extract was evaluated for total phenolic content using the Folin-Ciocalteu method and total flavonoid content using the aluminium chloride colorimetric assay. Afterward, the acute oral toxicity of the extract was determined following the Organisation for Economic Co-operation and Development (OECD) guideline 423. Additionally, two doses of Aerva persica (100 and 200 mg/kg body weight (BW)) were evaluated for their nootropic potential against D-galactose-induced memory impairment. The nootropic potential of the crude extract was assessed through a behavioural study and brain neurochemical analysis. Behavioural studies involved the evaluation of spatial reference- working memory using the radial arm maze test and the Y-maze test. Neurochemical analysis was performed to determine the brain's acetylcholine, acetylcholinesterase, glutathione (GSH), and malondialdehyde (MDA) levels.

RESULTS

The total phenolic content and total flavonoid content were found to be 179.14 ± 2.08 μg GAE/mg and 273.72 ± 3.94 μg QE/mg, respectively. The Aerva persica extract was found to be safe up to 2000 mg/kg BW. Following the safety assessment, the experimental mice received various treatments for 14 days. The behavioural analysis using the radial maze test showed that the extract at both doses significantly improved spatial reference-working memory and reduced the number of total errors compared to disease control groups. Similarly, in the Y-maze test, both doses significantly increased the alteration percentage and the percentage of novel arm entry (both indicative of intact spatial memory) compared to disease control. In neurochemical analysis, Aerva persica at 200 mg/kg significantly normalised the acetylcholine level (p<0.0001) and GSH level (p<0.01) compared to disease control. However, the same effect was not observed with Aerva persica at 100 mg/kg. Additionally, Aerva persica at 200mg/kg BW significantly decreased the acetylcholinesterase level (p<0.0001) and decreased the brain's MDA level (p<0.01) compared to the disease control, whereas the effect of Aerva persica at 100 mg/kg BW in reducing acetylcholinesterase was non-significant.

CONCLUSION

Based on the results, it can be concluded that the nootropic potential of Aerva persica was comparable to that of the standard drug, Donepezil, and the effect might be attributed to the higher content of flavonoids and phenolic compounds.

Safety and prognostic relevance of acetylcholine testing in patients with stable myocardial ischaemia or myocardial infarction and non-obstructive coronary arteries

BACKGROUND

Intracoronary provocation testing with acetylcholine (ACh) is crucial for the diagnosis of functional coronary alterations in patients with suspected myocardial ischaemia and non-obstructive coronary arteries.

AIMS

Our intention was to assess the safety and predictive value for major adverse cardiovascular and cerebrovascular events (MACCE) in patients presenting with ischaemia with non-obstructive coronary arteries (INOCA) or with myocardial infarction with non-obstructive coronary arteries (MINOCA).

METHODS

We prospectively enrolled consecutive INOCA or MINOCA patients undergoing intracoronary ACh provocation testing.

RESULTS

A total of 317 patients were enrolled: 174 (54.9%) with INOCA and 143 (45.1%) with MINOCA. Of these, 185 patients (58.4%) had a positive response to the ACh test. Complications during ACh provocative testing were all mild and transient and occurred in 29 (9.1%) patients, with no difference between patients with positive or negative responses to ACh testing, nor between INOCA and MINOCA patients. A history of paroxysmal atrial fibrillation, moderate/severe diastolic dysfunction and a higher QT dispersion at baseline electrocardiogram were independent predictors of complications. MACCE occurred in 30 patients (9.5%) during a median follow-up of 22 months. The incidence of MACCE was higher among patients with a positive ACh test (24 [13.0%] vs 6 [4.5%], p=0.017), and a positive ACh test was an independent predictor of MACCE.

CONCLUSIONS

ACh provocation testing is associated with a low risk of mild and transient complications, with a similar prevalence in both INOCA and MINOCA patients. Importantly, ACh provocation testing can help to identify patients at higher risk of future clinical events, suggesting a net clinical benefit derived from its use in this clinical setting.

Vasospastic Angina Diagnosed by the Spasm Provocation Test with the Combined Use of the Acetylcholine and Ergonovine Provocation Tests

The spasm provocation test (SPT) is important for diagnosing vasospastic angina (VSA), and acetylcholine (ACh) is usually used for this test in Japan. However, some patients with VSA have negative SPT results with the use of the standard ACh regimen alone. We herein report two cases in which VSA was diagnosed by the SPT with the combined use of ACh and ergonovine (EM). VSA could not be diagnosed in either case by the SPT using ACh infusions alone. For patients with negative SPT results, cardiologists should consider performing the SPT using a combination of ACh and EM.

t-Resveratrol Protects against Acute High Glucose Damage in Endothelial Cells

Postprandial hyperglycemia in diabetic and nondiabetic subjects is associated with endothelial dysfunction. Evidence shows that high glucose generates oxidative stress and a pro-inflammatory state promoting the development of cardiovascular diseases. trans-Resveratrol (t-RV) has been shown to reduce cardiovascular risk. To determine whether t-RV acts as a protector against acute high glucose (AHG)-induced damage, two in vitro models, rat aortic rings (RAR) and human umbilical vein endothelial cells (HUVEC) were used. RAR pretreated with AHG (25 mM D-glucose) for 3 h dramatically decreased the endothelium-dependent relaxation (EDR) induced by acetylcholine in phenylephrine (PE)-precontracted vessels. However, coincubation with t-RV significantly mitigated the damage induced by AHG on EDR. Pretreatment with AHG did not affect the vasodilation induced by sodium nitroprusside. HUVEC treated with t-RV decreased cytotoxicity and reduced radical oxygen species production induced by AHG. Taken together, these results suggest that t-RV can mitigate the AHG-induced EDR damage through a mechanism involving ROS scavenging and probably an increase in the bioavailability of NO.

Augmented Pla2g4c/Ptgs2/Hpgds axis in bronchial smooth muscle tissues of experimental asthma

Rationale

Augmented smooth muscle contractility of the airways is one of the causes of airway hyperresponsiveness in asthmatics. However, the mechanism of the altered properties of airway smooth muscle cells is not well understood.

Objectives

To identify differentially expressed genes (DEGs) related to the bronchial smooth muscle (BSM) hyper-contractility in a murine asthma model.

Methods

The ovalbumin (OA)-sensitized mice were repeatedly challenged with aerosolized OA to induce asthmatic reaction. Transcriptomic profiles were generated by microarray analysis of BSM tissues from the OA-challenged and control animals, and KEGG (Kyoto Encyclopedia of Genes and Genomes) Pathway Analysis was applied.

Measurements and main results

Tension study showed a BSM hyperresponsiveness to acetylcholine (ACh) in the OA-challenged mice. A total of 770 genes were differentially expressed between the OA-challenged and control animals. Pathway analysis showed a significant change in arachidonic acid (AA) metabolism pathway in BSM tissues of the OA-challenged mice. Validation of DEGs by quantitative RT-PCR showed a significant increase in PLA₂ group 4c (Pla2g4c)/COX-2 (Ptgs2)/PGD₂ synthase 2 (Hpgds) axis. PGD₂ level in bronchoalveolar fluids of the OA-challenged mice was significantly increased. A 24-h incubation of BSM tissues with PGD₂ caused a hyperresponsiveness to ACh in naive control mice.

Conclusions

AA metabolism is shifted towards PGD₂ production in BSM tissues of asthma. Increased PGD₂ level in the airways might be a cause of the BSM hyperresponsiveness in asthma.

Captopril augments acetylcholine-induced bronchial smooth muscle contractions in vitro via kinin-dependent mechanisms

Angiotensin converting enzyme (ACE) inhibitors therapy is aassociated with bothersome dry cough as an adverse effect. The mechanisms underlying this adverse effect are not clear. Therefore, influence of captopril (an ACE inhibitor) on acetylcholine (ACh)-induced bronchial smooth muscle contractions was investigated. Further, the mechanisms underlying the captopril-induced changes were also explored. In vitro contractions of rat bronchial smooth muscle to cumulative concentrations of ACh were recorded before and after exposure to captopril. Further, the involvement of kinin and inositol triphosphate (IP₃) pathways for captopril-induced alterations were explored. ACh produced concentration-dependent (5-500 µM) increase in bronchial smooth muscle contractions. Pre-treatment with captopril augmented the ACh-induced contractions at each concentration significantly. Pre-treatment with aprotinin (kinin synthesis inhibitor) or heparin (inositol triphosphate, IP₃-inhibitor), blocked the captopril-induced augmentation of bronchial smooth muscle contractions evoked by ACh. Further, captopril-induced augmentation was absent in calcium-free medium. These results suggest that captopril sensitizes bronchial smooth muscles to ACh-induced contractions. This sensitization may be responsible for dry cough associated with captopril therapy.

Antispasmodic effects of myrrh due to calcium antagonistic effects in inflamed rat small intestinal preparations

Myrrh is the oleo-gum resin of mainly Commiphora molmol and as a powdered substance, one compound in the traditional medicinal product Myrrhinil-Intest®, which has been used for the treatment of unspecific, inflammatory intestinal disorders. The aim of the present study was to evaluate the antispasmodic effect of myrrh under healthy and inflamed conditions, and to evaluate a calcium-antagonistic effect as a possible mode of action. Therefore, an ethanolic myrrh extract was tested for its effects on muscle tone and acetylcholine-induced contractions in untreated and inflamed rat ileum/jejunum preparations. Inflammation was experimentally induced by 2,4,6-trinitrobenzene sulfonic acid (10 mM, 30 min). Additionally, the effect of the calcium channel agonist Bay K8644 in the presence of varying myrrh extract concentrations was examined. Myrrh extract (0.99 mg/mL) suppressed the acetylcholine-induced contraction down to 25.8 % in untreated and 15.2 % in inflamed preparations. Myrrh extract (0.15; 0.25 and 0.35 mg/mL) induced a concentration-dependent rightward shift of the Bay K8644 concentration-response curve in untreated and inflamed preparations with a significant EC50 shift. Schild analysis resulted in a pA2 value of 0.93 for untreated preparations. Increasing myrrh extract concentrations induced a concentration-dependent decrease of the agonistic maximum effect in untreated and inflamed preparations down to 15.8 % and 25.8 %, respectively, for the highest concentration leading to a pD2 value of 0.58. Myrrh extract reduced intestinal muscle tone and acetylcholine-induced contraction of untreated and inflamed ileum/jejunum preparations based on dual calcium antagonism characterized by a right shift of the agonistic dose-response curve and a depression of the maximum effect. The resulting reduction of intestinal motility and spasmolytic effects provide a rationale for the symptom treatment of intestinal disorders such as irritable bowel syndrome.

Inhibition of p21 activated kinase (PAK) reduces airway responsiveness in vivo and in vitro in murine and human airways

The p21-activated protein kinases (Paks) have been implicated in the regulation of smooth muscle contractility, but the physiologic effects of Pak activation on airway reactivity in vivo are unknown. A mouse model with a genetic deletion of Pak1 (Pak1(-/-)) was used to determine the role of Pak in the response of the airways in vivo to challenge with inhaled or intravenous acetylcholine (ACh). Pulmonary resistance was measured in anesthetized mechanically ventilated Pak1(-/-) and wild type mice. Pak1(-/-) mice exhibited lower airway reactivity to ACh compared with wild type mice. Tracheal segments dissected from Pak1(-/-) mice and studied in vitro also exhibited reduced responsiveness to ACh compared with tracheas from wild type mice. Morphometric assessment and pulmonary function analysis revealed no differences in the structure of the airways or lung parenchyma, suggesting that that the reduced airway responsiveness did not result from structural abnormalities in the lungs or airways due to Pak1 deletion. Inhalation of the small molecule synthetic Pak1 inhibitor, IPA3, also significantly reduced in vivo airway responsiveness to ACh and 5-hydroxytryptamine (5-Ht) in wild type mice. IPA3 inhibited the contractility of isolated human bronchial tissues to ACh, confirming that this inhibitor is also effective in human airway smooth muscle tissue. The results demonstrate that Pak is a critical component of the contractile activation process in airway smooth muscle, and suggest that Pak inhibition could provide a novel strategy for reducing airway hyperresponsiveness.

Angiographic and clinical characteristics of patients with acetylcholine-induced coronary vasospasm on follow-up coronary angiography following drug-eluting stent implantation

Recent studies have shown that drug-eluting stents (DES) induce vascular endothelial dysfunction in both Cypher and Taxus stents. These studies evaluated coronary vasomotion in the peristent coronary segment for 1 lesion with 1 DES. The angiographic and clinical characteristics of real-world patients with coronary spasm following DES implantation have not been well documented.

METHODS AND RESULTS

All patients at our hospital who underwent coronary angiography at follow up after DES deployment (Cypher and Taxus stents) between July 2007 and March 2009 were included. We performed an acetylcholine (ACh) provocation test for diagnosing coronary vasospasm in 3 vessels, except in patients with significant stenosis or contraindications to ACh administration. ACh provocation test was positive in 36/55 of the coronary arteries (65.4%) and in 30/42 of the patients with DES (71.4%). There was no difference in the positive rate between patients with and without symptoms. A total of 13/20 asymptomatic patients (65.0%) also showed positive results. In patients with positive results in the ACh provocation test, vasoconstriction at segments distal to the stent was exaggerated compared with corresponding segments in non-stented vessels (0.46 ± 0.27 versus 0.31 ± 0.20, respectively; p = 0.008). Vessels with positive results had a longer stent length compared with those with negative results (31.6 ± 13.6 mm versus 24.2 ± 11.2 mm, respectively; p = 0.049).

CONCLUSION

Coronary vasoconstriction was exaggerated at distal segments in DES-implanted vessels compared to non-stented vessel segments and stent length was longer in the ACh provocation test positive group.

Dose-dependent inhibition of allergic inflammation and bronchial hyperresponsiveness by budesonide in ovalbumin-sensitised Brown-Norway rats

Corticosteroids are known to inhibit bronchial hyperresponsiveness (BHR) and allergic inflammation but there is little information on its dose-dependence. We examined the effect of different doses of the glucocorticosteroid budesonide in an allergic model. Brown-Norway rats were sensitised to ovalbumin (OVA) and pretreated with an intra-gastric dose of budesonide (0.1, 1.0, or 10 mgkg(-1)). Exposure to OVA induced BHR, accumulation of eosinophils in the bronchoalveolar lavage (BAL) fluid and in the airways submucosa. Budesonide dose-dependently inhibited BAL fluid influx of lymphocytes, eosinophils and neutrophils, tissue eosinophils and lymphocytes and BHR. At 0.1 mgkg(-1), budesonide did not inhibit these parameters but at 1 mgkg(-1), BAL fluid eosinophils and T-cells, and submucosal T-cells were significantly reduced. At 10 mgkg(-1), budesonide suppressed BHR, BAL fluid inflammatory cells numbers and tissue eosinophilia. T-cell numbers were more related to BHR than eosinophil numbers. Budesonide inhibited both airway inflammation and BHR, but BAL fluid eosinophil cell counts may be dissociated from BHR.

[Shock during spasm provocation tests with acetylcholine: four case reports]

Four patients suffered shock during the spasm provocation test with acetylcholine. An 84-year-old man with acute coronary syndrome was treated with stent implantation in the mid left anterior descending artery. Before discharge, acetylcholine test demonstrated coronary spasm in both the proximal left anterior descending artery and proximal left circumflex artery. A 61-year-old woman was admitted to the hospital because of recurrent rest and effort chest pain. Coronary arteriography showed no significant stenosis but shock was observed by intracoronary injection of acetylcholine due to diffuse severe coronary vasospasm in the proximal left anterior descending artery and left circumflex artery. Shock occurred in 4 of 1110 (0.36%) consecutive acetylcholine tests. Coronary spasm was gradually relieved and recovered from shock by the intraarterial administration of small amounts of norepinephrine and isosorbide dinitrate. Although the acetylcholine spasm provocation test is safe and reliable, care is required even during a selective procedure.

Usefulness of translesional pressure gradient and pharmacological provocation for the assessment of intermediate renal artery disease

OBJECTIVE

We sought to determine the hemodynamic significance of intermediate RAS by measuring translesional systolic pressure gradients (TSPG), using a pressure-sensing guidewire at baseline and after acetylcholine (ACh) induced hyperemia, following selective renal artery angiography.

BACKGROUND

Renal artery stenosis (RAS) is a cause of reversible hypertension and nephropathy. Stenting effectively relieves RAS, however improvement in blood pressure control or renal function is variable and unpredictable. Hemodynamic significance is usually present with RAS when diameter stenosis is >75%, but is less predictable in intermediate (30%-75%) RAS.

METHODS

Twenty-two patients (26 renal arteries) with uncontrolled hypertension underwent invasive hemodynamic assessment because of intermediate RAS, defined as radiocontrast angiographic diameter stenosis (DS) between 30% and 75% (quantitative DS was measured prospectively). Translesional pressure gradients were measured using a 0.014" pressure-sensing wire. Hyperemia was induced by administration of intrarenal ACh.

RESULTS

Visual and measured angiographic lesion severity did not correlate with TSPG either at baseline (visual DS, R(2) = 0.091, P = 0.13; measured DS, R(2) = 0.124, P = 0.07) or with hyperemia (visual DS, R(2) = 0.057, P = 0.24; measured DS, R(2) = 0.101, P = 0.12). Baseline and maximal hyperemic gradient did correlate (R(2) = 0.567; P < 0.05). Pharmacological provocation produced a significant increase in TSPG (mean; baseline, 18 +/- 21 vs. hyperemia, 34 +/- 41 mm Hg; P < 0.05). A hemodynamically significant lesion (TSPG > 20 mm Hg) was found in 14/26 (54%) arteries (13 patients); 13 (60%) patients subsequently underwent renal artery stenting for hemodynamically significant RAS. At follow-up (at least 30 days), there was a significant decrease in systolic blood pressure (mean; 167 +/- 24 vs. 134 +/- 19 mm Hg; P < 0.001).

CONCLUSIONS

Intrarenal administration of ACh induces hyperemia and can be used to unmask resistive renal artery lesions. Gradient measurement and induced hyperemia may be warranted in the invasive assessment of intermediate renal artery stenoses, rather than relying on stenosis severity alone. Further study is needed to determine whether translesional pressure gradients and pharmacological provocation predict clinical benefit after renal artery stenting.

Effect of MX-68 on airway inflammation and hyperresponsiveness in mice and guinea-pigs

MX-68 is a newly synthesized antifolate, which is a derivative of methotrexate (MTX). In this paper, the effect of MX-68 on allergic airway responses in mice and guinea-pigs was studied. In the first experiment, antigen-induced airway inflammation and airway hyperresponsiveness (AHR) to acetylcholine in mice were examined and compared with the effects of classical antifolate methotrexate and prednisolone. Mice were sensitized with ovalbumin as an antigen and challenged with ovalbumin inhalation three times. After the last inhalation, AHR and airway inflammation were observed. An increase in Th2 cytokines (IL-4 and IL-5) and a decrease in a Th1 cytokine (IFN-gamma) in the bronchoalveolar lavage fluid (BALF), as well as an elevation of the immunoglobulin level in serum, were observed in sensitized mice. Oral administration of MX-68 had no effect on changes of body weight, but prednisolone reduced body weight during the experiment. The antigen-induced AHR and increases in the number of eosinophils and lymphocytes in BALF were significantly inhibited by MX-68. MX-68 interfered with the elevation of IL-4 and IL-5 levels in BALF, but had no effect on the decrease in IFN-gamma. Moreover, MX-68 significantly inhibited the elevation of serum IgE and IgG levels. In the guinea-pig model for bronchial asthma, biphasic increases in airway resistance (immediate asthmatic response, IAR, and late asthmatic response, LAR), as well as accumulated inflammatory cells in BALF, were observed after repeated antigen challenge. These asthmatic responses and inflammatory signs were significantly decreased by administration of MX-68. These results suggest that MX-68 obviously has an anti-inflammatory effect in an animal model of asthma and would be useful clinically for the treatment of bronchial asthma.

Induction of coronary artery spasm by two pharmacological agents: comparison between intracoronary injection of acetylcholine and ergonovine

BACKGROUND AND OBJECTIVES

There have been few studies comparing the clinical usefulness for the induction of coronary artery spasm (CAS) between acetylcholine (ACh) and ergonovine (ER). This study is designed: (1) to examine the duration of effect after intracoronary injection of ACh on the responsible vessels using a 0.014 inch, 15 MHz Doppler guide wire, and (2) to evaluate the efficacy of two pharmacological agents, ACh and ER, for the induction of CAS in patients with <50% stenosis in the cardiac laboratory.

METHODS

Phasic coronary flow velocity patterns were recorded at rest and during ACh tests in 22 patients with normal or near-normal coronary arteries. The tip of the guide wire was placed on the proximal right coronary artery (RCA) and mid-left anterior descending artery. We measured the time required to baseline level of average peak velocity after intracoronary injection of ACh. We performed selective intracoronary administration of both ER and ACh in the same 171 patients (106 men, 65 women, mean age of 62+/-10 years) with <50% stenosis. Under no medication, ACh was injected first in incremental doses of 20, 50, and 80 microg into the RCA and of 20, 50, and 100 microg into the left coronary artery (LCA). Ten minutes later, ER was administered at 10 microg/min for four minutes for a maximal dose of 40 microg on the RCA and at 16 microg/min over four minutes for a total dose of 64 microg on the LCA. Positive spasm was defined as > or =99% luminal narrowing.

RESULTS

The time-averaged peak velocity returned to baseline after intracoronary injection of ACh within 10 minutes in all 120 procedures, consisted of 19 with positive spasm (RCA (n=10): 245+/-33 s; LCA (n=9): 351+/-187 s) and 101 with negative spasm (RCA (n=48): 155+/-62 s, LCA (n=53): 248+/-106 s). In the overall results, there was no difference concerning the incidence of provoked spasm between the two pharmacological agents (ACh: 33% versus ER: 32%, NS). Coronary spasms were induced by either pharmacological agent in 134 vessels. Concordance in this study was 94% in all vessels, whereas the remaining 6% of vessels were different from each other. The non-concordance rate of the right coronary artery was significantly higher than that of the left coronary artery (10% versus 4%, p<0.01). However, ER provoked more focal spasms, whereas ACh provoked more diffuse and distal spasms, compared with each other. Seventy-four (55%) of the 134 vessels had coronary spasms in the same coronary arteries. Concordance of both provoked spasm sites and spasm configurations in the same coronary artery was observed in only 18 (13%) vessels. No serious or irreversible complications were observed during the two sequential tests.

CONCLUSIONS

As a spasm provocation test, there were no differences between ACh and ER. We recommend the supplementary use of these two pharmacological agents for the induction of CAS in the cardiac laboratory, if available.

Coronary microvascular spasm causes myocardial ischemia in patients with vasospastic angina

OBJECTIVES

We aimed to test the hypothesis that coronary microvascular spasm (MVS) alone causes myocardial ischemia in patients with angina attributable to epicardial coronary spasm, and to determine whether there is a difference in clinical characteristics between those with and without microvascular spasm.

BACKGROUND

Patients with "vasospastic angina" have epicardial coronary artery spasm, but it is unknown whether coronary microvessel disease also contributes to the occurrence of angina in these patients.

METHODS

We studied 55 consecutive patients with angina in whom epicardial coronary spasm was provoked by intracoronary acetylcholine (ACH).

RESULTS

In 14 patients (25.5%, Group 1), submaximal dose of ACH induced myocardial ischemia (chest pain, ischemic electrocardiogram changes, lactate production) without large epicardial spasm, suggesting the occurrence of coronary microvascular spasm. By contrast, the remaining 41 patients (Group 2) had evidence of myocardial ischemia only when epicardial spasm was angiographically demonstrated. The Group 1 patients were predominantly women (p < 0.05) and had a history of prolonged (>30 min) chest pain (p < 0.05), whereas the Group 2 patients were more likely men and smokers (p < 0.01).

CONCLUSIONS

Myocardial ischemia most probably due to coronary MVS was demonstrated in a sizable portion of patients with epicardial vasospasm, preferentially in women having both typical and prolonged anginal pain. The result suggests that coronary microvascular disease may also contribute to angina in patients with "vasospastic angina."

Safety evaluation of routine intracoronary acetylcholine infusion in patients undergoing a first diagnostic coronary angiogram

BACKGROUND

Recent findings imply prognostic significance of intracoronary acetylcholine infusion for endothelial function testing. We evaluated whether routine use of this test in coronary angiography patients is safe.

METHODS

Patients undergoing a first diagnostic coronary angiography were selected to receive intracoronary acetylcholine for endothelial function evaluation. The relation between adverse reactions during infusion and risk factors was analyzed with a logistic regression model. Included in the multiple logistic regression model were the variables with a univariate P value < 0.20.

RESULTS

Adverse reactions occurred in 16% (49/299) of the patients. This included two life-threatening events caused by occlusive spasm and flow limitation in the left coronary artery. Other adverse events were chest pain (n = 38), AV block or sinus bradycardia (n = 10), dyspnea (n = 3). Adverse reactions were more likely to occur in patients younger than 60 years of age (relative risk, 5.6 [2.2-14.3]).

CONCLUSION

Intracoronary acetylcholine infusion is safe, but may lead to serious adverse reactions. Care should be taken especially in patients younger than 60 years of age. Routine use of acetylcholine infusion can thus only be justified if it has important prognostic significance. This has to be proven further in large prospective studies.

Class I antiarrhythmic drug and coronary vasospasm-induced T wave alternans and ventricular tachyarrhythmia in a patient with Brugada syndrome and vasospastic angina

A 50-year-old man presented with a history of transient chest pain and palpitations. The 12-lead ECG at rest showed normal sinus rhythm. A slight ST segment elevation was observed in leads V1 to V3. During hospitalization, atrial fibrillation developed, and oral pilsicainide was administered. Thirty minutes after the drug was given, the ECG showed marked ST segment elevation in leads V1 to V3, and T wave alternans became visible in leads V2 and V3. Self-terminating ventricular tachycardia was initiated following frequent ventricular premature complexes, which showed a left bundle branch block pattern. The coronary angiogram was normal, but in the provocation test of vasospastic angina, acetylcholine administration into the left coronary artery resulted in complete occlusion of the left anterior descending and circumflex arteries. Marked ST segment elevation developed in leads I, aVL, and V3 to V6 concomitant with visible QT/T alternans in leads V4 and V5, and ventricular tachyarrhythmia was initiated. Brugada syndrome and vasospastic angina coexisted in this patient, and T wave alternans can be used as a predictor of ventricular tachyarrhythmias in such patients.

Diet-induced mild hyperhomocysteinemia and increased salt intake diminish vascular endothelial function in a synergistic manner

OBJECTIVES

We investigated the influence of hyperhomocysteinemia and high salt intake on sodium handling, oxidative state, vascular endothelial function and blood pressure in a rat model.

METHODS

Eight-week-old male Sprague-Dawley rats were divided into subgroups and maintained for 4 weeks prior to experimentation on either control chow containing 0.36% methionine and 0.5% NaCl; or one of the following modified diets containing either 0.7% methionine, 8% NaCl or 0.7% methionine + 8% NaCl. Sodium handling, homocysteine metabolism, lipid profile, NO synthesis, oxidative state, blood pressure and relaxation to acetylcholine of carotid rings were evaluated and compared.

RESULTS

Diet-induced mild hyperhomocysteinemia (plasma homocysteine levels 1.4-fold higher than control), by itself, had no significant influence on sodium excretion, vascular endothelial function and blood pressure. Increased salt intake had no influence on homocysteine metabolism, vascular endothelial function and blood pressure. The coexistence of mild hyperhomocysteinemia and high salt intake significantly diminished vascular endothelial function (rmax to acetylcholine; control chow 83.2 +/- 6.2%, 0.7% methionine diet 74.7 +/- 3.9%, 8% NaCl diet 85.1 +/- 4.6%, 0.7% methionine + 8% NaCl diet 57.9 +/- 6.6%) but manifested no rise in blood pressure. No significant difference in oxidative state was observed in this analysis.

CONCLUSIONS

Diet-induced mild hyperhomocysteinemia, the extent of which is comparable with the levels that are associated with a predisposition to common atherosclerotic diseases, was found to induce vascular endothelial dysfunction only when accompanied by high salt intake.

[Molecular mechanism of exocytosis in neural and immune system]

Exocytosis is a common process for the secretion of physiologically active substances such as neurotransmitter, hormone, and inflammatory mediators. Exocytosis is triggered by an increase in intracellular calcium ion concentration. At the nerve terminal, voltage dependent calcium channels (VDCCs) are responsible for this calcium increase. There are several types of VDCC which are different from each other in their electro-physiological and pharmacological characteristics. In order to identify the types of VDCC at the cholinergic nerve terminal, acetylcholine (ACh) release from the electric organ synaptosomes was measured in the presence of type-specific channel blockers. At least three types of VDCC were involved in the ACh release, and N- and P/Q-type VDCC had a major contribution. Adenosine receptor A1 was coupled with N-type VDCC and had negative feedback regulation of ACh release, while A2 receptor coupled with P/Q-type VDCC enhanced the ACh release. Investigation of the inhibitory effects of antibodies from patients of autoimmune disease Lambert-Eaton syndrome on ACh release revealed that P/Q-type channel was a target for the autoantibodies. Unlike the nerve terminal, little is known about the mechanism and molecules involved in the exocytosis of immune cells. Ion channel activities of secretory granule proteins of mast cells were observed. The calcium dependency of the open probability of the channel was similar to that of histamine release from mast cells. We also showed the expression of some SNARE proteins in RBL-2H3 cells. Localization and dynamics of VAMP-7 and syntaxin-3 after antigen stimulation suggested the involvement of SNARE proteins in the exocytosis of mast cells.

Major complications during spasm provocation tests with an intracoronary injection of acetylcholine

This study sought to clarify major complications associated with acetylcholine testing. Serious major complications, such as sustained ventricular tachycardia, shock, and cardiac tamponade were determined in 4 of 715 patients (0.56%), but no cases of death or irreversible complications occurred. The spasm provocation test using acetylcholine should be performed carefully, although it is considered a safe and reliable method.

The local effects of systemic digoxin on the cutaneous microcirculation

OBJECTIVE

The present study was designed to explore whether digoxin modifies cutaneous vascular responses to an endothelium-dependent vasodilator (acetylcholine) or to the vasoconstrictor norepinephrine.

METHODS

In a double-blind cross-over study 12 healthy subjects received digoxin 0.25 mg twice daily (after adequate loading doses) or placebo for a total of 11 days. Dose-response curves to iontophoresis of acetylcholine or norepinephrine were constructed at day 11. Laser Doppler flux (LDF) was measured at the same sites. Mean arterial pressure (MAP) was measured non-invasively and cutaneous vascular conductance (CVC) was calculated (CVC = LDF/MAP).

RESULTS

Serum concentrations of digoxin were within the therapeutic range [1.3 (0.5) ng x ml(-1); mean with (SD)]. Blood pressure and heart rate were significantly lower during supine rest under digoxin treatment [mean with (SD); minute 10 to 70 of supine rest; systolic blood pressure: 121 (11) mmHg (placebo) vs 116 (11) mmHg (digoxin); P = 0.001; diastolic blood pressure: 63 (6) mmHg vs 58 (8) mmHg; P = 0.007; heart rate: 60 (10) beats x min(-1) vs 54 (8) beats x min(-1); P = 0.001]. Digoxin also caused significantly higher baseline CVC [169 (25) Perfusion Units (PU) x mmHg(-1) (digoxin) vs 109 (14) PU x mmHg(-1)(placebo); P = 0.013] and significantly increased the vasoconstriction to norepinephrine iontophoresis. Acetylcholine iontophoresis was unaltered by digoxin treatment.

CONCLUSIONS

Digoxin does not modify the cutaneous vascular response to an administered endothelium-dependent vasodilator. It reduces resting heart rate, blood pressure and baseline cutaneous blood flow and augments the vasoconstrictive effect of exogenous norepinephrine. The findings do not support the hypothesis that digoxin lowers diastolic blood pressure through a direct action on blood vessels.

[Round Table: urticaria with a physical cause]

Physical urticaria comprises a series of clinically differentiated conditions in which wheals develop as a result of physical stimuli: mechanical (friction, pressure), cold, heat, increased body temperature, exercise exposure to sunlight, vibration and contact with water. The present study reviews their clinical, diagnostic and treatment characteristics. Although the precise prevalence of physical urticaria is not know, it nevertheless represents the most common form of urticaria of known etiology in children. Symptomatic dermatographism is the most frequent presentation in children; it may be present from birth and persist indefinitely. In order to study the prevalence of dermatographism in our pediatric population, we randomly selected 238 children of both sexes (128 boys and 110 girls) aged 2 to 14 years, in the Paternal Health Care Center (Valencia, Spain). An evaluation was made of skin response 5 minutes after the application of pressure (3,200 g/cm2) along a 5-cm extent of skin on the back, using a dermatographometer. A positive response was considered when a wheal over 2 mm in diameter developed; in this context, the prevalence of dermatographism was 24%, with a significant predominance of females (33%) over males (16%). According to the data obtained from the anamnesis, 41% of the children with dermatographism referred exanthema in response to friction and pressure compatible with symptomatic dermatographism, versus only 5% of those who tested negatively. Lastly, 42% of the children with dermatographism referred intense local reaction (5 cm or more) in response to mosquito bites, versus only 16% of the children who tested negatively for dermatographism. The study of bronchial reactivity to metacholine in 17 children with dermatographism but no bronchial asthma (based on the Chatham method) proved positive in 13 cases (76%). Seven of these 17 children (41%) yielded positive skin tests (3 referred symptoms of rhinitis, with no manifestations of asthma in any case), and the metacholine challenge proved positive in 5 (71%). Ten of the children showed negative skin testing for aeroallergens - with positive metacholine testing in 8 (80%). These results indicate a high prevalence of bronchial hyper-responsiveness in children with dermatographism, suggesting the existence of an association between skin and bronchial hyper-reactivity. Skin tests with aeroallergens were made in 45 of the 58 children with positive dermatographism; 38% were found to be positive for at least one of the allergens studied, a figure that increased to 43% when only considering children over the age of 7 years. This points to a high prevalence of atopy among children with dermatographism. In order to evaluate the prevalence of dermatographism in the atopic population, we studied 100 patients in the 4-14 years age range suffering from respiratory pathology associated with sensitization to aeroallergens. A positive response to pressure (3,200 g/cm2) was observed in 47% of cases, this being significantly higher than the prevalence observed among the general pediatric population.

Administration of acetylcholine and vasoactive intestinal polypeptide to atopic eczema patients

Responses to acetylcholine (ACh) and vasoactive intestinal polypeptide (VIP) were investigated in atopic eczema (AE) patients. To elucidate the involvement of histamine to ACh-provoked vasoreactions and sensations, we applied a selective H1-antagonist (cetirizine) 3 h prior to the ACh-administration. Solutions of acetylcholine (ACh, 0.55 M) and vasoactive intestinal polypeptide (VIP, 1.5x 10(-5) M) were injected (10 microl) intracutaneously into the volar forearm of 14 healthy subjects and 14 atopic eczema (AE) patients. The substances were applied as single stimulus as well as in combination. Sensations evoked by the stimulation were recorded using 2 visual analog scales (VAS). Vasoreactions were analyzed with the new technique of computer assisted video image analysis. With this method we measured the dynamics of the flare development and the extension of the final flare size independent of the observer's assessment. In control subjects the development and extension of the final flare size was almost similar, regardless whether ACh and VIP were applied in combination or separately. Compared to healthy controls, after injection of ACh, VIP and the combination of VIP and ACh smaller flare sizes were recorded in AE patients. After VIP was given, the control subjects reported pruritus, which was significantly augmented compared to AE patients. In contrast, controls reported a burning pain after the injection of ACh, whereas AE patients felt predominantly pruritus. Itch sensation after the combined application of VIP and ACh was significantly elevated in AE patients. Consequently, we assume that mediators of sudomotor neurons, i.e., VIP and ACh meet in AE patients apparently sensitized nociceptive primary afferents and induce exaggerated itch, pain and flare responses. When pretreated with the selective H1-antagonist cetirizine before ACh was injected, pain and erythema due to ACh was diminished in healthy controls. In contrast, cetirizine did not influence the size of erythema and the magnitude of sensation in AE patients. We conclude, that the release of histamine is not involved in ACh-induced erythema and pruritus in AE. These data provide evidence that pruritus can be elicited in atopic eczema by a cholinergic, histamine independent mechanism.

Detection of platelets activated during acetylcholine-induced coronary vasospasm

Although platelet activation may play a role in coronary artery spasm, platelets activated following coronary vasospasm have not been clinically detected. We performed flow cytometric analysis of activation-dependent granular proteins, CD62P (P-selectin), CD63, PAC-1 (activated glycoprotein [GP] IIb/IIIa) and thrombospondin on the platelet plasma membrane in patients who exhibited acetylcholine-induced coronary vasospasm and compared findings with those in control patients without vasospasm. We simultaneously investigated the plasma levels of thrombin anti-thrombin III complex (TAT), plasmin alpha2-plasmin inhibitor complex (PIC), and thrombomodulin. In patients with vasospasm, the expression of CD62P, CD63 and PAC-1 on the platelet membrane surface increased in coronary sinus blood samples following coronary vasospasm, although the expression in aortic samples did not change. The TAT level also increased in the coronary sinus after vasospasm. Platelets might be activated by coronary vasospasm within the coronary circulation. The platelet activation process may be modulated by thrombin generation.

Intracoronary acetylcholine-induced prolongation of monophasic action potential in long QT syndrome

Two patients with long QT syndrome, who had episodes of syncope, underwent recordings of the monophasic action potential (MAP) from the right ventricle. Intracoronary administration of acetylcholine (ACh) induced prolongation of MAP duration and caused Torsade de Pointes (Tdp) in both patients. In one patient, intravenous atropine administration did not induce any change in MAP duration. In the other patient, ACh was administered after atropine. According to the results of the present study, abnormal regulation of the muscarinic receptor-mediated K-channel may be involved in the mechanism causing prolongation of MAP duration caused by ACh administration.

Intraoperative miotics and posterior capsular opacification following phacoemulsification with intraocular lens insertion

BACKGROUND AND OBJECTIVES

Posterior capsular opacification (PCO) is a frequent complication following phacoemulsification with intraocular lens (IOL) implantation. A series of consecutive patients receiving capsular bag-fixated, silicone IOL implants were assessed for both incidence of PCO and the administration of intraoperative miotics.

PATIENTS AND METHODS

During a 5-year period, 477 consecutive eyes were retrospectively evaluated. Surgeries were grouped according to intraoperative miotic agent: 0.01% carbachol or 1.0% acetylcholine. Patients receiving no miotic drug served as a control group. Yttrium-aluminum-garnet (YAG) laser posterior capsulotomy was performed on patients with clinically significant PCO.

RESULTS

The percentage of eyes requiring YAG laser capsulotomy was similar for the three groups: 21.6% (25 of 91) for the carbachol group, 18.4% (14 of 62) for the acetylcholine group, and 18.6% (53 of 232) for the control group. A chi-squared analysis indicated that the difference among the groups was not statistically significant. The three groups also had similar average follow-up times between surgery and YAG capsulotomy (carbachol group = 52.2 weeks, acetylcholine group = 47.5 weeks, and control group = 48.3 weeks).

CONCLUSION

Intraocular miotics do not increase the incidence of PCO.

Acetylcholine-induced coronary microvascular vasospasm in a patient with angina pectoris and normal coronary angiogram--a case report

We demonstrated a continuous intracoronary infusion of acetylcholine-induced marked decrease of coronary blood flow estimated by intracoronary Doppler flow wire without significant epicardial coronary narrowing. This case can be called a patient with microvascular vasospastic angina.

Acetylcholine is an inducer of itching in patients with atopic eczema

As previous experimental studies disproved histamine as the main mediator of eliciting pruritus in atopic eczema (AE), we examined the neurocutaneous sensations in 15 patients with AE and in 15 age- and sex-matched non-atopic controls after i.c. injection of acetylcholine (Ach, 0.5 M, 20 microliters) or buffered saline. The sensory perceptions were rated by the participants of the study with regard to their quality and intensity using a visual analogue scale. Simultaneously, the vascular reactions to Ach were recorded by the examinators via laser Doppler fluxmetry as well as flare and wheal planimetry. In contrast to the approximately equal flare and wheal extensions in either group, the cutaneous sensations differed significantly. The patients complained of 'pure' itching that developed shortly after Ach injection, whereas the control subjects reported only burning pain. Moreover, the patients perceived their sensations significantly earlier and significantly longer than did the controls. The study provides evidence that Ach plays an important role in the pathogeny of pruritus in patients with AE. Further investigations of the neuronal mechanisms involved in this atopy-related effect of Ach have to be performed.

[Reduction of endothelial cell number by cataract operation with intraocular thymoxamine administration. A randomized, double-blind study]

BACKGROUND

Thymoxamine, an alpha-1-receptor blocker, considerably enhances miosis when given intraocularly in combination with acetylcholine. We investigated whether intraocular use of thymoxamine 0.02% reduced the number of endothelial cells.

PATIENTS AND METHODS

After phacoemulsification of 59 eyes, either thymoxamine 0.02%, acetylcholine 1.0% or buffered saline solution was given intraocularly. With a contact specular microscope, corneal endothelial cell photographs were taken on the day before treatment and 3 days and 6 weeks after surgery.

RESULTS

There were no statistically significant differences between endothelial cell counts of eyes treated with thymoxamine (-7.2%), acetylcholine (-10.2%) or BSS (-9.4%).

CONCLUSION

This study shows for the first time that thymoxamine, when given in the anterior chamber after phacoemulsification, does not cause a greater loss of endothelial cells than acetylcholine or buffered saline solution.

Effects of acetylcholine and carbachol on bovine corneal endothelial cells in vitro

PURPOSE

To assess the relative cytotoxicity of Miochol (1% acetylcholine and mannitol), Miostat (0.01% carbachol, sodium, potassium, magnesium, and calcium salts), and their individual components using in vitro models of bovine corneal endothelial cells (BCECs).

SETTING

Laboratories of the Departments of Ophthalmology and Physiology, The University of Texas Health Science Center, Houston.

METHODS

The study was divided into four experiments. Experiment 1 used a confluent model to compare the relative cytotoxicity of Miochol and Miostat on BCECs following short-term exposure. In Experiments 2, 3, and 4, the proliferation model (preconfluent BCECs) was used to detect the possible cytotoxicity of individual components in the commercial preparations of the miotics; i.e., the preconfluent BCECs were exposed to buffered salt solutions containing mannitol (1%, 3%, and 4%), acetylcholine (0.5%, 1%, and 2%), or carbachol (0.1%, 0.5%, and 1%) for 3 hours.

RESULTS

Confluent BCECs exposed to Miochol for 30 minutes underwent necrosis and degeneration, while those treated with Miostat did not show any morphological changes. None of the tested solutions except 2% acetylcholine and 1% carbachol caused observable changes in the nuclear densities of BCECs at 24, 72, 120, and 168 hours.

CONCLUSION

The major components of Miochol (acetylcholine and mannitol) were found to be nontoxic; the cytotoxicity of the preparation was possibly due to the lack of an appropriate balanced salt solution. These findings may influence the selection of a miotic for use during intraocular surgery.

Coronary thrombosis induced by intracoronary acetylcholine injection in a patient with normal coronary myocardial infarction

A 67-year-old male was admitted with acute myocardial infarction. Coronary thrombolysis was carried out because complete occlusion of the obtuse marginal branch (OM) in the circumflex artery was detected in emergent coronary angiography, and recanalization of the OM was obtained at 3 hours after the onset of chest pain. No significant stenosis of the OM was found in coronary angiography performed at the recovery stage. After intracoronary acetylcholine injection to the left coronary artery, coronary spasm was induced and coronary thrombosis was observed in the left anterior descending artery thereafter. These findings indicate the possibility that the etiology of myocardial infarction is coronary thrombosis induced by coronary spasm.

High thoracic epidural anesthesia does not alter airway resistance and attenuates the response to an inhalational provocation test in patients with bronchial hyperreactivity

BACKGROUND

The functional relevance of an intact pulmonary sympathetic innervation for airway resistance is unknown. We therefore evaluated whether or not pulmonary sympathetic denervation by thoracic epidural anesthesia decreases the threshold of an inhalational provocation with acetylcholine in 20 patients with documented bronchial hyperreactivity scheduled for elective upper abdominal or thoracic surgery.

METHODS

Baseline inhalational provocation with acetylcholine was performed 2-4 days before surgery. The acetylcholine threshold concentration for a hyperreactivity response (i.e., for a 20% decrease in forced expiratory volume in 1 s and a 100% increase in total respiratory resistance by oscillometry) was determined. On the day of surgery a second inhalative provocation with acetylcholine was performed 45 min after the patients had received 6-8 ml epidural bupivacaine 0.75% (n = 10), intravenous bupivacaine (1.2 mg.min-1, n = 6), or 6-8 ml epidural saline (n = 4). The acetylcholine threshold concentration for a hyperreactive response was again determined. We also measured vital capacity, forced expiratory volume in 1 s as a percentage of vital capacity, spread of sensory blockade (pin prick), skin temperature on hand and foot (telethermography).

RESULTS

During thoracic epidural anesthesia, C4-T8 skin temperature increased significantly on hand and foot indicating widespread sympathetic blockade including the lungs. Compared to values obtained immediately before pulmonary sympathetic blockade, forced expiratory volume in 1 s as a percentage of vital capacity, and total respiratory resistance by oscillometry remained unchanged, while vital capacity decreased. Compared to baseline the acetylcholine threshold concentration for the hyperreactive response increased threefold after epidural as well as after intravenous bupivacaine. Epidural saline evoked no directional changes in the acetylcholine threshold concentration.

CONCLUSIONS

We conclude that in patients with bronchial hyperreactivity 1. blockade of pulmonary sympathetic innervation seems to be of no relevance for airway resistance and 2. both epidural and intravenous bupivacaine substantially attenuate the response to an inhalational provocation with acetylcholine.

Intracoronary acetylcholine-induced prolongation of the QT interval and Torsade des Pointes in long QT interval syndrome

A 75-year-old female had syncopal episodes from Torsade des Pointes (TdP). Her electrocardiogram showed a prolonged QT interval which was not associated with electrolyte imbalances or drug therapy. Similar electrocardiographic abnormalities were found in three family members. Electrophysiologic study showed a mildly prolonged effective refractory period of 260-290 msec, but no tachyarrhythmia was induced. Coronary arteriography was normal but intracoronary acetylcholine unexpectedly induced a prolongation of the QT interval and TdP. Direct action of acetylcholine on the ventricular muscle was suggested.

Methylergonovine-induced diffuse coronary spasm in a patient with exercise-induced coronary spasm after heart transplantation

Coronary artery spasm is a rarely reported condition after heart transplantation. We report a case of exercise-induced coronary artery spasm in a patient 1-year after orthotopic heart transplantation. Serial quantitative coronary angiography showed significant diffuse loss of luminal diameter. Provocative testing with intracoronary acetylcholine and intravenous methylergonovine maleate was performed in an effort to document efficacy of the antispasm regimen. Infusion of acetylcholine into the left anterior descending coronary artery resulted in transient closure of the vessel. Diffuse spasm resulting in hypotension and ventricular fibrillation occurred with intravenous methylergonovine maleate administration. Because of the risk of provoking diffuse spasm, intravenous administration of methylergonovine maleate should be avoided in the posttransplantation setting. Review of the literature suggests that coronary artery spasm after transplantation is often associated with severe transplant coronary artery disease and may be associated with a poor prognosis. Coronary artery spasm may be a more common cause of syncope and death after transplantation than it is currently thought to be.

Tosyl arginine methyl ester induces bronchoconstriction in rabbit bronchial tissues in vitro: a possible new mediator in asthma

Tosyl arginine methyl ester induced bronchoconstriction in rabbit bronchial rings mounted in vitro with a calculated EC50 of 5.6 x 10(-5) M as compared with acetylcholine which induced sustainable constriction with an EC50 of 2.5 x 10(-6) M. Tosyl arginine methyl ester, however, had definite bronchoconstricting properties though less potent than acetylcholine. We concluded that our data support the hypothesis that tosyl arginine methyl ester could be a possible biochemical mediator of airway contraction.

Intraocular miotics and postoperative inflammation

Sixty patients scheduled for planned extracapsular cataract extraction with intraocular lens (IOL) implantation were randomly assigned to receive acetylcholine chloride, carbachol, or balanced salt solution (BSS) immediately after IOL placement and at the end of the surgical case. As part of the postoperative evaluation, patients were examined at the first and eighth postoperative day with a Kowa FC-1000 laser flare and cell meter to assess objectively the amount of postoperative inflammation. At day one and day eight, the amount of cell and flare in the carbachol group was significantly greater than in the acetylcholine group or in the BSS control group. The acetylcholine group had significantly less flare than the BSS group at day one; yet there was no difference between the two groups at day eight, nor was there a significant difference in the amount of cells between day one and day eight. It is presumed that the prolonged miosis seen in the carbachol group delays the re-establishment of the blood-aqueous barrier after surgery, causing the inflammatory response.

Acetylcholine-induced myocardial ischemia without epicardial coronary artery spasm: a possible vasospasm of small coronary arteries--a case report

Small-vessel vasospasm has been speculated upon as a possible cause of chest pain in patients with normal-appearing coronary angiograms. In this report, a patient who experienced typical chest pain during acetylcholine testing, which caused ST segment elevation without epicardial coronary spasm, is presented. This finding suggests that small-vessel vasospasm may be involved in the induction of myocardial ischemia in patients with normal epicardial coronary arteries.

Spontaneous coronary artery dissection after a natural course for 10 years--a case report

We encountered a patient with spontaneous coronary artery dissection complicated by acute inferior myocardial infarction. A 58-year-old male was admitted to our hospital due to acute inferior myocardial infarction in 1979. Coronary angiography performed 4 weeks after the onset showed a double lumen divided by a linear intimal flap in the right coronary artery, suggesting coronary artery dissection, but no apparent occlusion. Subsequently, he had been medicated with nitrates without any recurrent infarction. In February, 1989, 10 years after the first examination, coronary angiography was again performed and showed that the dissection had remained unchanged. Acetylcholine infusion into the right coronary artery induced coronary spasm. The prognosis of this condition seems to be better than has been generally considered, particularly in patients such as ours in whom the involvement of coronary spasm in the development of coronary artery dissection and myocardial infarction is suggested. When coronary spasm in controlled by treatment with nitrates or calcium antagonists, an uneventful course may be expected.