Biomedical subjects

J Lonovics

Publications and source records attributed to J Lonovics.

At least 73 records · Page 4Linked to original sources

PubMed1997

Plasma levels of TNF and IL-6 following induction of acute pancreatitis and pentoxifylline treatment in rats.

Activation of cytokine cascade is a decisive factor in determining the pathobiology of different inflammatory processes including acute pancreatitis. The purposes of this study were to determine the TNF and IL-6 levels after the induction of acute necrotizing pancreatitis, and to establish the effects of pentoxifylline on the cytokine production and the severity of pancreatitis. Acute necrotizing pancreatitis was induced by the retrograde injection of 200 microliters taurocholic acid into the pancreatic duct in male Wistar rats. TNF was titrated in a bioassay on cell line WEHI clone 164. IL-6 was measured via its proliferative action on the IL-6 dependent mouse hybridoma cell line B-9. Seven mg/kg pentoxifylline was administered intraperitoneally at the time of operation and/or 24 hours later. Rats were sacrificed, 48 or 72 hours after the operation. The TNF bioassay revealed high levels of TNF (36.6 +/- 6.0 U/ml) in the control group whereas levels decreased to zero in the pentoxifylline-treated group. The IL-6 bioassay likewise demonstrated high levels of IL-6 in the control group and markedly decreased levels in the pentoxifylline treated group (7083 +/- 2844 pg/ml, 6463 +/- 1307 pg/ml vs. 137.5 +/- 85.5 pg/ml, respectively, p < 0.05). The high mortality observed in the control group (43%) was sharply decreased by pentoxifylline administration to 11%. The data suggest that pentoxifylline is capable of modifying the cytokine production after 48 hours of induction of acute pancreatitis.

Amylases↗

PubMed1997

[Contact litholysis of common bile duct calculi. Study of 44 patients].

OBJECTIVES: Endoscopic sphincterotomy has become a generally accepted method for extracting common bile duct stones in high risk or cholecystectomized patients. However, stone extraction is impossible by the usual methods in 5 to 10% of cases. The purpose of this study was to evaluate the effect of a recently developed solvent system in patients with large bile duct stones. METHODS: Forty four patients (15 men and 29 women, median age of years) underwent contact dissolution after unsuccessful Dormia extraction. Solvents were administered via a nasobiliary catheter in 41 patients following papillotomy and through a T-tube in 3 patients. Solvent mixtures (26 mM ethylene diamine tetraacetic acid, 40 mM sodium deoxycholate and 30% dimethyl sulfoxide in an alkaline aqueous solution; and a 70/30 dimethyl sulfoxide/methyl tert-butyl ether mixture) were infused continuously and alternatively for 2 hours. RESULTS: Bile duct stones disappeared in 13-24 hours of infusion in 11 patients. In 29 patients, a clear reduction in stone volume occurred, allowing complete endoscopic extraction of the fragments. In 4 patients, the size of the stone did not change. Only mild and transient side-effects including abdominal pain (68%), nausea (72%), vomiting (52%), diarrhea and sleepiness (50%) were observed. CONCLUSION: Direct dissolution therapy could be an effective method for the non-surgical management of large bile duct stones in selected patients when intra- or extracorporeal lithotripsy is unsuccessful.

Aged↗

PubMed1996

[Effect of interferon-alpha2b therapy in chronic hepatitis C].

In chronic hepatitis C the interferon treatment given three times a week in a dosage of 3 million units (MU) normalizes the values of alanin-amino-transferase in a part of cases (25-40%), and produces bettering in the subjective complains of patients. In the short term therapy (3-6 months) the activity of ALT increases again after leaving the therapy, and the disease becomes active. The aim of this multicenter study in Hungary was to give newer data in the case of longterm efficacy with alpha-interferon. Ninety-one patients with chronic hepatitis C were selected into the open prospective clinical study in university and hospital departments. Treatment protocol was the following: Patients with chronic hepatitis C diagnosed by clinical and histological methods were treated with interferon-alpha 2B given 3 times a week in a dosage of 3 MU. Treatment period had lasted for one year and afterwards the patient had been on control for an other half a year. In non responder cases after 3 month treatment with interferon the dose of therapy was increased for 3 x 5 MU. In 37 cases (40.6%) out of 91 patients the authors found longterm sustained remission and in other 22 cases (24.2%) they observed a partial remission (among them 5 cases with late relapse). The rate of longterm sustained remission under 40 years was higher, than above 40. Higher rate was found when the treatment was started with a shorter chronicity of the disease. On te basis of the results the authors conclude: Interferon-alpha 2B is a good therapeutic modality for the treatment of patients with chronic hepatitis C. Efficacy of therapy is higher in younger patients and also in earlier application.

Adult↗

PubMed1996

[Studying the effect of enzyme replacement in chronic pancreatitis].

Authors studied the effect of Neo-Panpur in chronic pancreatitis patients with moderate or severe exocrine pancreatic insufficiency. Patient's complaints, laboratory parameters and pancreatic function were also registered. Indications of pancreatic substitution therapy and the advantages of Neo-Panpur treatment are also discussed.

Adult↗

PubMed1996

Impaired nitrergic relaxation of the sphincter of Oddi of hyperlipidaemic rabbits.

Field stimulation relaxed the sphincter of Oddi muscle rings of the rabbit after incubation with phentolamine, oxprenolol and atropine (all 1 microM). The relaxation was blocked by NG-nitro-L-arginine methyl ester (30 microM) and was reversed by 3 mM L-arginine but not D-arginine. Sphincter of Oddi preparations from hypercholesterolaemic rabbits exhibited contractions under the same conditions. We conclude that nitrergic relaxation is impaired in the sphincter of Oddi from hypercholesterolaemic rabbits.

Animals↗

PubMed1996

Time-course changes in serum cytokine levels in two experimental acute pancreatitis models in rats.

Activated leukocytes and cytokines have important roles in the multi-system involvement during acute pancreatitis. The changes in the serum level of tumor necrosis factor-a (TNF-alpha) and interleukin-6 (IL-6) over time were investigated in two experimental acute pancreatitis models in rats. Mild edematous pancreatitis was induced with an overdose of cholecystokinin octapeptide (CCK-8), while a severe hemorrhagic form of pancreatitis was induced by ligation of the common bilio-pancreatic duct. The rats were examined 2, 4, 8, 16, 24 and 48 h after pancreatitis induction. The severity of the inflammation was assessed by measurement of the serum amylase activity, quantification of the edema, and histological examination. Serum TNF-alpha and IL-6 were determined by bioassay, using the TNF-sensitive WEHI 164 and the IL-6-dependent B9 cell lines, respectively. In CCK-8-induced acute pancreatitis, the pancreatic weight/body weight ratio (pw/bw) and amylase level were significantly elevated at 2 h, and the maximum levels were observed at 4 h (8.19 +/- 1.13 mg/g and 69.4 +/- 12.8 x 10(3) U/ml, respectively). Both parameters subsequently decreased continuously during the observation period. The serum IL-6 level was significantly increased at 4 h relative to the controls (123.3 +/- 5.8 vs 37.5 +/- 15 pg/ml), and then decreased continuously. In this model, only a moderate level of serum TNF-alpha was observed at 2 h. In the biliary type of acute pancreatitis, the ratio pw/bw increased continuously during the study and reached the maximum level at 48 h relative to the sham-operated control (8.8 +/- 1.4 vs 5.3 +/- 0.8 mg/g). The serum amylase level was significantly elevated at 2 h (43.2 +/- 13 x 10(3) U/ml), but then decreased continuously. The serum IL-6 reached its maximum level at 16 h (3800 +/- 447 pg/ml). In this model, increased TNF-alpha levels (75-300 U/ml) were measured 8, 16 and 24 h after pancreatitis induction. The results led to correlations between the serum IL-6 levels and the biochemical and morphological severity of acute pancreatitis in both experimental models. The data suggest that IL-6 and TNF-alpha may participate in the pathogenesis of these types of acute pancreatitis.

Acute Disease↗

PubMed1996

Cytokine level changes in L-arginine-induced acute pancreatitis in rat.

The role of different cytokines in the pathogenesis of L-arginine (Arg)-induced acute pancreatitis in rat, and the ability of KSG-504, a novel cholecystokinin receptor antagonist, to exert protection in this type of acute pancreatitis was evaluated. Male Wistar rats received 250 mg/100 g body weight of Arg intraperitoneally twice, at an interval of 1 h. Control rats received instead the same amount of glycine at the same times. Fifty mg/kg KSG-504 was injected subcutaneously 0.5 h before and 6, 18 and 36 h after the first Arg administration. Rats were examined 12, 24 and 48 h after pancreatitis induction. To assess the severity of inflammation, the edema was quantified, the serum amylase level was measured, and histologic examinations were performed. Serum tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) levels were determined by bioassay, using the TNF-sensitive WEHI 164 and the IL-6-dependent B9 cell lines, respectively. In Arg-induced acute pancreatitis, the amylase level was increased significantly at 12 h (48.600 +/- 3.980 U/l) and 24 h (30.800 +/- 3.813 U/l) vs. the control group (6.382 +/- 184 U/l). No significant alteration in the ratio pancreatic weight/body weight was found in the different groups. However, in Arg-induced acute pancreatitis, both the TNF-alpha (15.1 +/- 6.9 U/ml) and the IL-6 (39.6 +/- 19.2 pg/ml) levels were already elevated significantly at 12 h vs. the controls (3.1 +/- 0.8 U/ml and 15.2 +/- 3.1 pg/ml, respectively) and remained elevated at 24 and 48 h. Simultaneous KSG-504 administration did not modify the measured cytokine levels. No significant changes in plasma CCK levels were observed. In Arg-induced acute pancreatitis, histological evaluation revealed diffuse but microfocal necrobiotic alterations. No marked protective effects of KSG-504 were observed on histological sections. These results suggest that excessive doses of Arg induce severe acute pancreatitis in rat, with a simultaneous cytokine level elevation. Endogenous CCK does not seem to play an essential role in the pathogenesis of Arg-induced acute pancreatitis.

Acute Disease↗

PubMed1995

The loss of pacing-induced preconditioning in atherosclerotic rabbits: role of hypercholesterolaemia.

A brief rapid pacing has been shown to protect rabbit heart against global myocardial ischaemia induced by subsequent longer pacing. We studied whether pacing-induced preconditioning was reproducible in experimental hypercholesterolaemia. In conscious rabbits with an implanted right ventricular electrode and left ventricular polyethylene catheters, pacing of 500 bpm over 20 min induced an intracavitary ST-segment elevation of 3.2 +/- 0.41 mV, shortened ventricular effective refractory period and increased left ventricular end-diastolic pressure from prepacing 105 +/- 3.9 ms and 4.0 +/- 0.93 mmHg to post-pacing 62 +/- 6.4 ms and 27.9 +/- 7.2 mmHg, respectively. A 10-min preconditioning pacing followed by a 5-min interval markedly attenuated these test pacing-induced ischaemic changes. Rabbits were fed a cholesterol-enriched diet over 4, 8 and 12 weeks, responded to a 5- or 10-min pacing with ischaemic changes of the same degree as did controls to a 10- or 20-min pacing, respectively. A 4-week diet elevated total serum cholesterol from 1.7 +/- 0.4 to 24.1 +/- 2.9 mmol/l without apparent atherosclerotic lesions in the thoracic aorta assessed by Oil-Red O staining and planimetry, but it abolished protection induced by a 5-min preconditioning pacing. A 12-week diet increased serum cholesterol and lesion surface area to 26.9 +/- 3.2 mmol/l and 89.6 +/- 6.4%, respectively, and continued to block preconditioning. When these animals were refed normal chow over additional 6 weeks, serum cholesterol level dropped to 2.6 +/- 0.80 mmol/l with no change in atherosclerotic lesions, the preconditioning effect, however, recovered. We conclude that hypercholesterolaemia blocks preconditioning irrespective of the development of atherosclerosis.

Animals↗

PubMed1995

Evaluation of results of the prostigmine-morphine test with quantitative hepatobiliary scintigraphy: a new method for the diagnosis of sphincter of Oddi dyskinesia.

Attempts have long been made to use the prostigmine-morphine provocation test for the selection of postcholecystectomy patients suffering from sphincter of Oddi (SO) dyskinesia. Since the whole procedure is based upon the evaluation of subjective complaints, this test has frequently been criticized. To improve the diagnostic value of this method, we have visualized SO spasms during prostigmine-morphine provocation by means of quantitative hepatobiliary scintigraphy (QHBS). Twenty-two cholecystectomized patients with typical postprandial biliary pain were included in this study. In the first series of studies, QHBS with technetium-99m 2,6-diethylphenylcarbamoylmethyl-diacetic acid was performed in each patient 2 days before prostigmine-morphine provocation. The time to peak activity (Tmax) and the half-time of excretion (T1/2) over the liver parenchyma (LP), hepatic hilum (HH) and common bile duct (CBD), and the duodenum appearance time (DAT), were determined and served as control values. In the second series of experiments, sphincter spasms were evoked by prostigmine-morphine administration and visualized by means of QHBS. The same parameters were evaluated and serum levels of aspartate aminotransferase (AST) were determined simultaneously at regular intervals. In 12 patients who responded to prostigmine-morphine provocation with typical biliary pain and a significant AST elevation (Nardi positive group) the hepatobiliary scintigram demonstrated a marked biliary obstruction. Tmax and T1/2 over the LP, HH and CBD were significantly increased, while DAT was significantly longer relative to the corresponding data obtained without provocation. Four of the remaining ten patients indicated atypical abdominal pain during prostigmine-morphine provocation, but the AST level remained unchanged in all ten (Nardi negative group).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

[Direct dissolution therapy of biliary tract calculi].

The aim of this study was to evaluate the effect of a recently developed biphasic multicomponent solvent in 39 patients with biliary duct stones that are too large (15-35 mm) to be removed after endoscopic sphincterotomy. From November 1991 to October 1993, 37 patients with common bile duct stones were papillotomized during endoscopic retrograde cholangiography and a nasobiliary catheter was positioned above the stone. In 2 patients, the residual stones were dissolved via the T-tube inserted during cholecystectomy. Solvent mixtures (solvent 1:26 mM ethylene diamine tetraacetic acid, 40 mM sodium deoxycholate and 30% dimethyl sulfoxide in an aqueous buffer solution glycine-NaOH, pH: 9.2; solvent 2: a 70: 30 mixture of dimethyl sulfoxide and methyl-tert-butyl-ether) were infused continuously and alternatively for 2 h at a rate of 0.3-0.5 ml/kg b.w./h. In order to diminish the absorption of the solvent from the duodenum, charcoal was given orally periodically. Fluoroscopy indicated that the common bile duct stones disappeared during 13-24 h of infusion in 10 of 39 patients. In 25 patients, the size of the stones diminished sufficiently for them to be removed by basket extraction. In 4 patients, the size of the stone did not change and surgery (1 pt) or endoscopic stenting (3 pts) was required. Only mild toxic side-effects were observed, including laboratory abnormalities and moderate duodenitis (34/39). Transient abdominal pain and/or cramp (21/39), nausea and vomiting (34/39) and diarrhoea (19/39) were the most common complaints during treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1994

Regional differences in nitric oxide-mediated relaxation of the rabbit sphincter of Oddi.

We studied the role of the L-arginine-nitric oxide (NO) pathway in non-adrenergic, non-cholinergic (NANC) relaxation of the rabbit sphincter of Oddi by recording changes in isometric tension in response to electrical field stimulation in two series of experiments. In a first set of experiments, biliary sphincters of Oddi removed from New Zealand white rabbits were placed horizontally in an organ bath containing oxygenized, buffered (pH 7.4) Krebs solution. Contractile responses of the whole sphincter to field stimulation were determined. In the second set of experiments, sphincter of Oddi was divided into two parts and the effects of field stimulation were studied separately on areas close to the duodenal papilla (area I) and areas close to the common bile duct (area II). In the whole sphincter of Oddi, field stimulation induced an initial twitch-like contraction followed by relaxation proportional to the number of stimuli (3 and 10 stimuli at 20 Hz, 50 V, 0.1 ms). The magnitude of the contractile responses was considerably reduced by 1 microM atropine, phentolamine and oxprenolol (NANC solution). Field stimulation produced dose-dependent contractions of both segments of sphincter of Oddi in response to the same protocol as used with whole sphincter of Oddi. However, preincubation with NANC solution produced monophasic relaxations in response to field stimulation in area I, whereas area II preparations such as the whole sphincter of Oddi responded with contractions followed by minimal relaxations. Field stimulation failed to induce either contractions or relaxations in the presence of 1 microM tetrodotoxin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Differentiation between organic stenosis and functional dyskinesia of the sphincter of Oddi with amyl nitrite-augmented quantitative hepatobiliary scintigraphy.

Recurrent biliary pain after cholecystectomy is presumably due to sphincter of Oddi dysfunction (SOD). There is no ideal non-invasive test for SOD, and the diagnosis often relies on invasive procedures such as sphincter of Oddi (SO) manometry. Amyl nitrite-augmented quantitative hepatobiliary scintigraphy (QHBS) was performed on nine asymptomatic volunteers and 22 patients with SOD of biliary types I and II. Normal QHBS parameters were established in the asymptomatic volunteers. QHBS revealed a partial obstructive pattern in nine patients in whom SO stenosis was suspected and in 13 patients in whom SO dyskinesia was suspected. This obstructive pattern remained unchanged in the former group, but was completely relieved in the latter group of patients on amyl nitrite administration. In conclusion, amyl nitrite-augmented QHBS proved to be a useful non-invasive method in the diagnosis of SOD of biliary types I and II and permitted differentiation between organic stenosis and functional motor abnormalities of the SO.

Adult↗

PubMed1994

Cromakalim and cicletanine against pacing-induced myocardial ischemia in conscious rabbits.

Myocardial ischemia assessed by intracavital ST-segment elevation, shortening of ventricular effective refractory period (VERP), and increase in left ventricular end-diastolic pressure (LVEDP) was provoked by ventricular overdrive pacing (VOP) in conscious rabbits. Cromakalim (10 micrograms/kg), an ATP-sensitive K+ channel opener, and cicletanine (30 mg/kg), a cGMP-phosphodiesterase inhibitor, reduced VOP-induced ST-segment elevation and LVEDP-increase. Under resting conditions, cromakalim lowered blood pressure, increased heart rate (HR), and shortened VERP, whereas cicletanine decreased HR, prolonged VERP without changing blood pressure. Co-administration of cromakalim and cicletanine additively reduced VOP-induced ST-segment elevation, shortening of VERP, and LVEDP-increase. Cicletanine did not change cromakalim-induced hypotension but abolished reflexogenic tachycardia. This suggests that VERP shortening is not a prerequisite for the anti-ischemic effect of cromakalim, and the combination of these drugs may afford a potent and safe anti-ischemic effect without affecting hypotension induced cromakalim.

Animals↗

PubMed1994

Loss of preconditioning in rabbits with vascular tolerance to nitroglycerin.

A preceding right ventricular overdrive pacing (VOP) of 500 b.p.m. for 5 min, markedly reduced the severity of global myocardial ischaemia produced by a subsequent 5-min VOP in conscious rabbits. This VOP-induced preconditioning developed in parallel with an increase in cardiac cyclic guanosine 3':5'-monophosphate (cyclic GMP) content. VOP-induced preconditioning was abolished when the animals had been made tolerant to the vasodilator effect of nitroglycerin (NG). In the heart of the NG-tolerant rabbits, neither VOP nor preconditioning increased cyclic GMP content. This suggests that changes by NG tolerance of cyclic GMP metabolism may account for the loss of VOP-induced preconditioning.

Animals↗

PubMed1994

Ventricular overdrive pacing-induced anti-ischemic effect: a conscious rabbit model of preconditioning.

To study whether ventricular overdrive pacing (VOP) induces preconditioning, rabbits were equipped with right ventricular electrode catheters for pacing and intracavital recording and polyethylene cannulas in the left ventricle and right carotid artery to measure intraventricular pressure and blood pressure. One week after surgery in conscious animals, VOP at 500 beats/min over 2, 5, or 10 min resulted in an intracavital S-T segment elevation, shortening of ventricular effective refractory period, decrease in maximum rate of pressure development and blood pressure, and increase in left ventricular end-diastolic pressure proportional to the duration of stimulation. A 5-min preconditioning VOP applied 5 or 30 min before a 10-min VOP markedly attenuated ischemic changes, whereas a 2-min VOP had no effect. In anesthetized rabbits, a 5-min VOP slightly increased guanosine 3',5'-cyclic monophosphate (cGMP) and profoundly elevated adenosine 3',5'-cyclic monophosphate (cAMP) content in left ventricular samples. When this VOP was preceded (5 or 30 min) by a preconditioning VOP, the cAMP increase was significantly attenuated, whereas the cGMP increase was amplified. We conclude that a single 5-min VOP induces preconditioning in association with alterations in cardiac cyclic nucleotide contents.

Animals↗

PubMed1994

Time-course changes in pancreatic laboratory and morphologic parameters in two different acute pancreatitis models in rats.

The aim of this work was to study in rats the temporal course of laboratory parameters and morphologic features in acute pancreatitis induced by cholecystokinin octapeptide (CCK-8) or by a closed duodenal loop. Pancreatitis was induced either with an overdose of CCK-8 (3 x 75 micrograms/kg at 1 h intervals) or by ligation of the duodenum on both sides of the bilio-pancreatic duct. The animals were examined at 0, 2, 4, 8, 16 and 24 h after AP induction. In CCK-8-induced acute pancreatitis, the pancreatic weight/body weight ratio (8.2 +/- 1.1 mg/g) and the amylase level (44.8 +/- 7.5 x 10(3) U/ml) were significantly increased vs. the controls (4.5 +/- 0.8 mg/g and 3.3 +/- 0.2 x 10(3) U/ml, respectively) 2 h after the intervention. The plasma CCK was significantly increased at 4 h (4.55 +/- 1.7 pM) and remained elevated thereafter. The tissue malonyldialdehyde concentration was significantly elevated at 8 h (0.28 +/- 0.07 mumol/mg pancreas) vs. the controls (0.20 +/- 0.02 mumol/mg pancreas). In closed duodenal loop-induced acute pancreatitis, the ratio pancreatic weight/body weight steadily increased during the study; it reached its maximum level at 24 h (7.1 +/- 0.5 mg/g) vs. the sham-operated control (4.8 +/- 0.9 mg/g). The serum amylase level was significantly elevated at 2 h (47.1 +/- 9.3 x 10(3) U/ml), and then decreased steadily. Plasma CCK values were significantly higher than the controls throughout the study. A significant increase in the tissue malonyldialdehyde concentration (0.94 +/- 0.15 mumol/mg vs. 0.20 +/- 0.01 mumol/mg pancreas) appeared at 4 h. Our data indicate that in CCK-8-induced acute pancreatitis the laboratory signs of pancreatitis are most expressed at 4 h, whereas the morphologic changes culminate 8 h, following the last CCK injection. In closed duodenal loop-induced acute pancreatitis, the histologic findings showed a progressive deterioration. Endogenous CCK and oxygen-derived free radicals seem to play a role in the pathogenesis of both types of acute pancreatitis.

Acute Disease↗

PubMed1993

[Diagnosis of Verner-Morrison syndrome (VDHA) and its treatment with sandostatin an streptozocitin].

A case report is presented of a man with Verner-Morrison syndrome of extreme severity, caused by an unresectable pancreatic VIPoma. The pathological role of vasoactive intestinal polypeptide (VIP) is discussed in the pathogenesis of Watery Diarrhoea, Hypokalaemia, Achlorhydria (WDHA) syndrome. The authors describe the typical symptoms of the syndrome and provide a diagnostic and therapeutic strategy. Plasma level of VIP was determined by the authors' own VIP RIA method. Administration of a long acting somatostatin analogue, octreotide (Sandostatin, Sandoz) at a dose of 100 micrograms daily, decreased the plasma level of VIP from about 55 to 38 fmol/ml, which was associated with complete regression of the diarrhoea. Due to the 'escape phenomenon' the dose of Sandostatin was gradually increased and finally completed with streptozotocin (Zanosar, Upjohn) administration, which was repeated every 8 weeks. The combination of Sandostatin and streptozotocin resulted in complete regression of diarrhoea and substantial diminution of the tumour mass. The patient displayed a weight gain and returned to normal life.

Humans↗

PubMed1993

Zaprinast, cicletanine, and verapamil attenuate overdrive pacing-induced myocardial ischemia in conscious rabbits.

In conscious rabbits equipped with right ventricular electrode and left ventricular polyethylene catheters, zaprinast and cicletanine, inhibitors of phosphodiesterase (PDE) V and PDEs I and V, respectively, as well as verapamil, a Ca2+ channel blocker, decreased intracavital ST-segment elevation induced by ventricular overdrive pacing (VOP). Zaprinast and cicletanine attenuated VOP-induced QT reduction and increase in left ventricular end-diastolic pressure (LVEDP), whereas verapamil increased LVEDP. These results suggest that inhibition of cGMP-PDEs can protect heart against ischemia.

3',5'-Cyclic-AMP Phosphodiesterases↗