Effects of nicorandil on QT prolongation and myocardial damage caused by citalopram in rats

Citalopram is a selective serotonin re-uptake inhibitor (SSRI) antidepressant; it exhibits the greatest cardiotoxic effect among SSRIs. Citalopram can cause drug-induced long QT syndrome (LQTS) and ventricular arrhythmias. We investigated the protective effect of nicorandil, a selective mitochondrial KATP (mito-KATP) channel opener, on LQTS and myocardial damage caused by citalopram in male rats. In a preliminary study, we determined that the minimum citalopram dose that prolonged the QT interval was 102 mg/kg injected intraperitoneally. For the main study, rats were divided randomly into five experimental groups: untreated control, normal saline + citalopram, nicorandil + citalopram, 5-hydroxydecanoate (5-HD) + citalopram, 5-HD + nicorandil + citalopram. Biochemical and histologic data from blood and heart tissue samples from six untreated control rats were evaluated. Electrocardiographic parameters including QRS duration, QT interval, corrected QT interval (QTc) and heart rate (HR) were assessed, and biochemical parameters including malondialdehyde, reduced glutathione, glutathione peroxidase, superoxide dismutase were measured. We also performed histomorphologic and immunohistochemical examination of heart tissue. Citalopram prolonged QT-QTc intervals significantly and increased significantly the histomorphologic score and proportion of apoptotic cells, but produced no differences in the oxidant and antioxidant parameters. Nicorandil did not prevent citalopram induced QT-QTc interval prolongation and produced no significant changes in oxidant and antioxidant parameters; however, it did reduce histologic damage and apoptosis caused by citalopram.

Inhaled nitric oxide as rescue therapy in severe ARDS cases due to COVID-19 pneumonia: a single center experience

OBJECTIVE

Inhaled NO (iNO) has been recommended as rescue therapy in acute respiratory stress syndrome (ARDS) cases. In this study, we aimed to demonstrate the efficacy of iNO as a rescue therapy in patients with severe ARDS due to COVID-19.

PATIENTS AND METHODS

This retrospective study included patients with ARDS due to COVID-19 who were treated with iNO between March 2020 and January 2022 in the intensive care unit (ICU) of Inonu University. Patients' files were reviewed retrospectively, and demographic data, APACHE II and Sequential Organ Failure Assessment (SOFA) scores, initiation day of iNO and duration of iNO treatment, length of stay in hospital/ICU, blood biochemistry values, complete blood counts, inflammatory parameters, arterial blood gas values, lactate, PaO2/FiO2 ratios, anti-inflammatory drugs and outcome were recorded.

RESULTS

Data from 16 patients were reached. iNO was given at a dose of 20 ppm continuously. The mean duration of treatment with iNO was 3.5 days. All patients took the prone position except a single patient. While all patients received steroid therapy, four patients received anti-cytokine therapy, and five patients received intravenous immunoglobulin therapy. All patients were in severe ARDS with a mean PaO2/FiO2 ratio of 58 before iNO therapy. A significant increase in PaO2/FiO2 values was detected with the use of iNO (p<0.05). While three patients (19%) were discharged from the ICU, thirteen patients died.

CONCLUSIONS

In our study, it was determined that iNO applied as a rescue treatment in patients with severe ARDS improved oxygenation. Although the effect of iNO on survival was low, it may be interpreted as clinically significant considering the severity of the general clinical condition of the patients.

Effect of the selective mitochondrial KATP channel opener nicorandil on the QT prolongation and myocardial damage induced by amitriptyline in rats

OBJECTIVES

The aim of this study is to evaluate the protective effect of nicorandil, a selective mitochondrial KATP channel opener, on QT prolongation and myocardial damage induced by amitriptyline.

METHODS

The dose of amitriptyline (intraperitoneal, i.p.) that prolong the QT interval was found 75 mg/kg. Rats were randomized into five groups the control group, amitriptyline group, nicorandil (selective mitochondrial KATP channel opener, 3 mg/kg i.p.) + amitriptyline group, 5-hdyroxydecanoate (5-HD, selective mitochondrial KATP channel blocker, 10 mg/kg i.p.) + amitriptyline group and 5-HD + nicorandil + amitriptyline group. Cardiac parameters, biochemical and histomorphological/immunohistochemical examinations were evaluated. p < 0.05 was accepted as statistically significant.

KEY FINDINGS

Amitriptyline caused statistically significant prolongation of QRS duration, QT interval and QTc interval (p < 0.05). It also caused changes in tissue oxidant (increase in malondialdehyde)/anti-oxidant (decrease in glutathione peroxidase) parameters (p < 0.05), myocardial damage and apoptosis (p < 0.01 and p < 0.001). While nicorandil administration prevented amitriptyline-induced QRS, QT, QTc prolongation (p < 0.05), myocardial damage and apoptosis (p < 0.05), it did not affect the changes in oxidative parameters (p > 0.05).

CONCLUSIONS

Our results suggest that nicorandil, a selective mitochondrial KATP channel opener, plays a protective role in amitriptyline-induced QT prolongation and myocardial damage. Mitochondrial KATP channel opening and anti-apoptotic effects may play a role in the cardioprotective effect of nicorandil.

Anticoagulation with unfractionated heparin in patients with prosthetic valve thrombosis- a single center study

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

Surgical and thrombolytic therapy (TT) are used as effective treatment methods to treat obstructive Prosthetic valve thrombosis (PVT). However, TT is usually contraindicated in patients who suffer PVT in the early postoperative period (first three weeks) or those who present with an acute cerebral thromboembolism. Unfractionated heparin (UFH) infusion seems to be one of the appropriate treatment options in such patients.

PURPOSE

In this single-center study, we aimed to investigate the efficacy of UFH therapy in patients with PVT.

METHODS

This retrospective, observational, single center study included 136 PVT patients (mean age: 50.3 ± 14.6 years; female: 81, male: 55) who did meet the following criteria: (i) PVT with &gt;10 mm thrombus lenght; (ii) a thrombus with embolic risk despite no thrombolytic indication, accompanied with clinical entities such as gradient increase on the valve, acute coronary syndrome, infective endocarditis, and TIA.The success criteria of the treatment was defined as a 75% reduction in the thrombus burden in the absence of major non-fatal complications. Patients with a 50 75% reduction in the thrombus burden were considered as partially successful. The development of major complications indicated treatment failure.

RESULTS

The study included 16 (11.8%) aortic, 97 (71.3%) mitral, 19 (14%) aortic and mitral, 4 (2.9%) tricuspid prosthesis, with 27 (19.9%) obstructive and 109 (80.1%) non-obstructive thrombosis. During the follow-up, 66 (48,5%) patients showed a regression &gt; 50% in the thrombus burden without facing death or major non-fatal complications; therefore the UFH therapy was considered successful in these patients. Fifty-six patients had a &lt; 50% reduction in thrombus load despite the UFH treatment. Furthermore, 14 (10.3 %) patients suffered major complications. UFH treatment was assumed unsuccessful in these 70 patients (51.5%). Nature of the thrombus (27.1% vs. 12.1%; p = 0.028), thrombus area (1.1 (in a range of 0.7-1.6) cm2 vs. 0.8 (in a range of 0.6-1.2) cm2; p = 0.005] and the duration of UFH treatment (15.1 ± 6.7 days vs. 11.8 ± 7.2 days; p = 0.005) were significantly higher in the unsuccessful UFH group. The parameters that were found to be significantly different in the univariate analyses between patients with successful and unsuccessful UFH treatment were further evaluated in multivariate regression analysis. As a result, the obstructive nature of the thrombus (RR: 3.088, 95% CI: 1.191-8.006; p = 0.020), increased thrombus area (RR: 2.400, 95% CI: 1.184-4.864; p = 0.015), and increased duration of UFH therapy (RR: 1.073 95% CI: 1.016-1.133; p = 0.012) were identified as independent predictive parameters for a failed UFH therapy.

CONCLUSIONS

In this study, we have demonstrated that UFH treatment may be beneficial in patients with PVT that are unsuitable for surgical and TT. Our findings have revealed that the most significant factor affecting the success of UFH treatment is the thrombus burden. Abstract table 1  Abstract table 2

Comprehensive evaluation of intermittent mechanical valve obstruction: a retrieval study of 16 cases

Funding Acknowledgements

Type of funding sources: None.

Background

 The intermittent stuck valve is a rarely defined clinical situation, which can be life-threatening or benign, and the clinical features are not well-known.

Purpose

 A thorough investigation of the intermittent mechanical stuck valve"s etiology, diagnostic and treatment methods, and identifying parameters are associated with clinical severity

Methods

 Over 11 years (2010- 2021), 16 patients were subsequently selected from referrals to the Kosuyolu Training and Research Hospital"s echocardiography department. We collected the data retrospectively.

Results

 The evaluated patients consisted of  12 bi-leaflet mitral valve replacements (MVR) and two mono-leaflet MVR. Etiologies were classified as follows; residual chord with four patients, obstructive thrombus (OT) with two patients, non-obstructive thrombus (NOT) with two patients, vegetation with two patients, pannus, and OT coexistence with one patient, solely pannus with one patient. One of the residual chord patients with the frequency one of three-beat severe intermittent mitral regurgitation (MR) presented in dyspnea and underwent redo MVR. The other residual chord patients were in the mild condition who had lesser entrapment frequency. One of the two patients with OT had an ischemic cerebrovascular accident (CVA) with intermittent severe mitral stenosis (MS), while the other was in severe dyspnea. These two patients also underwent redo-MVR. Intermittent stuck valve due to NOT (n:2) presented with dyspnea. Both patients presented with intermittent moderate MR. Two patients presented with endocarditis with severe intermittent MR. One patient had obstruction one of the three beats due to the pannus formation who underwent surgery. One patient who recovered with TT had pannus and NOT coincidentally with a stuck valve in one of the three beats. 

One of the patients with mono-leaflet MVR had pannus and OT. In the other patient with mono-leaflet MVR, a stuck valve was observed in one of 12 beats secondary to arrhythmia.

In the collected data, there were two aortic valve replacements (AVR). One patient had moderate aortic regurgitation due to prominent calcification; the other had moderate obstruction due to pannus. We decided on follow-up medical treatment for these patients with the aortic valve. In the patient with pannus, stuck valve formation occurred one of six beats, and moderate aortic regurgitation arose one of two beats in the patient with calcification. 

Conclusions

 The intermittent stuck valve is rarely defined, may have catastrophic outcomes and necessitates a comprehensive approach. It requires elaborative examination in symptomatic patients with prosthetic valves. When making a treatment decision in these patients, as in other native or prosthetic valve patients, the degree of regurgitation or stenosis is essential. In particular, for intermittent stuck valves, the frequency of entrapment should play a fundamental role in making treatment decisions Abstract table 1  Abstract table 2

Management of mechanical ventilation in a morbidly obese patient with COVID-19-induced ARDS

Coronavirus disease 2019-induced acute respiratory distress syndrome (ARDS) is more severe in morbidly obese patients. Mechanical ventilation differs between obese and non-obese patients. We examined these differences in an obese (body mass index = 47 kg/m2) 32-year-old patient followed up in our clinic. The patient was admitted to the intensive care unit due to respiratory failure. Recruitment maneuvers were performed in pressure-controlled ventilation mode. The optimal positive end-expiratory pressure was 25 cm H2O. The inspiratory pressure was adjusted to 45 cm H2O to provide a tidal volume of 6 ml/kg and driving pressure ≤ 15. The patient was discharged with full recovery.

Effects of resveratrol on alpha-amanitin-induced nephrotoxicity in BALB/c mice

Alpha-amanitin (α-AMA), the primary toxin of Amanita phalloides, is known to cause nephrotoxicity and hepatotoxicity. Resveratrol is an antioxidant that has shown efficacy in many nephrotoxicity models. The aim of this study was to investigate the effects of resveratrol against the early and late stages of α-AMA-induced nephrotoxicity, compared to those of silibinin, a well-known antidote for poisoning by α-AMA-containing mushrooms. Mice kidney tissues were obtained from five groups: (1) α-AMA + NS (simultaneous administration of α-AMA and normal saline), (2) α-AMA + SR (simultaneous administration of α-AMA and resveratrol), (3) α-AMA + 12R (resveratrol administration 12 h after α-AMA administration), (4) α-AMA + 24R (resveratrol administration 24 h after α-AMA administration), and (5) α-AMA + Sil (simultaneous administration of α-AMA and silibinin). Histomorphological and biochemical analyses were performed to evaluate kidney damage and oxidant-antioxidant status in the kidney. Scores of renal histomorphological damage decreased significantly in the early resveratrol treatment groups (α-AMA + SR and α-AMA + 12R), compared to those in the α-AMA + NS group (p < 0.05). Catalase levels increased significantly in the α-AMA + SR group, compared to those in the α-AMA + NS group (p < 0.001). Early resveratrol administration within 12 h after α-AMA ingestion may reverse the effects of α-AMA-induced nephrotoxicity, partly through its antioxidant action, thereby suggesting its potential as a treatment for poisoning by α-AMA-containing mushrooms.

P6487Sequential combination of different thrombolytic therapy regimens in the management of patients with prosthetic valve thrombosis and stuck valves

Introduction

Prosthetic valve thrombosis (PVT) is serious complication among patients with prosthetic heart valves. Recently, thrombolytic therapy (TT) regimens with low-dose, slow and ultra-slow infusions of tissue type plasminogen activator (tPA) has been widely used as a first-line treatment for PVT. PVT with stuck valves is a special entity which deserves particular management. In our study, we aimed to investigate the effectiveness and safety of sequential combination of different TT regimens in the management of patients with PVT and stuck valves.

Methods

The study included 52 patients with PVT and stuck valves [female: 34 (65.4%), mean age: 47.5±12.4] who underwent TT with sequential combination of slow (25mg/6 hours) and ultra-slow (25mg/25 hours) infusion of low dose t-PA regimens which was mainly based on the New York Heart Association functional class of the patients according to a previously established algoritm. All patients were evaluated by cinefluoroscopy, transthoracic and transesophageal echocardiography (Figure 1).

Results

The median number of TT sessions with slow and ultra-slow infusion of tPA were 1 (0–2.75) and 3 (1.25–5) respectively. Total tPA dose was 120 (96–175) mg and TT was successful in 46 (88.4%) patients. There were 3 major complications (cerebrovascular accident: 1, intracranial bleeding: 1, gastrointestinal bleeding requiring transfusion: 1) and 6 minor complications. The in-hospital mortality rate was 1.9%. Increased thrombus area was found to be the only independent predictor of both failed TT and adverse events. Thrombus area above 1.45 cm2 predicted failed TT with a sensitivity of 83% and a specificity of 70% (AUC: 0.871; 95% CI: 0.752–0.991; p=0.003) and predicted adverse events with a sensitivity of 77% and a specificity of 73% (AUC: 0.854; 95% CI: 0.747–0.961; p=0.001). There was a moderate positive correletion between thrombus area and total tPA dose used (r=479; p<0.001).

Figure 1

Conclusion

This study demostrated that TT with sequential combination of slow and ultra-slow infusion of low dose t-PA regimens may be useful for the treatment of patients with PVT and stuck valves with acceptable success and complications rates.

Effects of Nigella sativa oil on ovarian volume, oxidant systems, XIAP and NF-kB expression in an experimental model of diabetes

We investigated the effects of Nigella sativa oil on ovary volume, nuclear factor-kappaB (NF-κB), X-linked inhibitor of apoptosis protein (XIAP) expression, and serum malondialdehyde (MDA), superoxide dismutase (SOD), total antioxidant status (TAS) and total oxidant status (TOS) levels in diabetic rats. We divided 21 adult female rats into three groups: controls, diabetics and diabetics + N. sativa oil. The diabetics + N. sativa oil group was given 0.2 mg/kg/day N. sativa oil 6 days/week for 4 weeks. NF-κB and XIAP expression was assessed in ovarian sections using immunohistochemistry. The right and left ovary volumes were calculated using stereology. We also measured serum MDA, SOD, TAS and TOS levels. We found that N. sativa oil reduced hyperglycemia, but not to control levels. N. sativa oil also exhibited antioxidant properties as demonstrated by reduced serum TOS and MDA levels, and increased SOD and TAS levels compared to controls. We found no significant difference in total ovarian volume, XIAP or NF-κB expression among the groups, which may be due to the short study period. Our findings suggest that N. sativa oil may be useful for reducing blood glucose levels and elevated oxidant activity in diabetic patients.

The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation

Haumea-one of the four known trans-Neptunian dwarf planets-is a very elongated and rapidly rotating body. In contrast to other dwarf planets, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system, and the Centaur Chiron was later found to possess something similar to Chariklo's rings. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea's equator and the orbit of its satellite Hi'iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea's spin period-that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea's largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.

A Comparison of the Effectiveness of Silibinin and Resveratrol in Preventing Alpha-Amanitin-Induced Hepatotoxicity

Amanita phalloides species mushrooms containing alpha-amanitin (α-AMA) are responsible for the majority of fatal mushroom intoxications and can lead to severe poisonings resulting in hepatotoxicity and acute hepatic failure. Existing antidotes, such as silibinin, are not sufficiently effective in the prevention and/or resolution of α-AMA-induced hepatotoxicity. We investigated the effects of resveratrol on α-AMA-induced hepatotoxicity and compared with silibinin, a known antidote using in vivo and in vitro toxicity models. In the in vivo protocol, resveratrol (30 mg/kg) was given simultaneously with α-AMA (α-AMA + SR) or 12 (α-AMA + 12R) or 24 (α-AMA + 24R) hr after α-AMA administration. Silibinin (5 mg/kg) (α-AMA + Sil) and normal saline (α-AMA + NS) were given simultaneously with α-AMA. We found that liver transaminase levels in α-AMA + SR and α-AMA + 12R groups and histomorphologic injury score in the α-AMA + SR, α-AMA + 12R, α-AMA + 24R and α-AMA + Sil groups were significantly lower than that of the α-AMA + NS group. Resveratrol decreased mononuclear cell infiltration, necrosis and active caspase-3 immunopositivity in the liver. In the in vitro protocol, the effects of resveratrol and silibinin were evaluated in a reduction in cell viability induced by α-AMA in THLE-2 and THLE-3 hepatocytes. Neither resveratrol nor silibinin was found to be effective in increasing cell viability decreased by α-AMA + NS. As a conclusion, resveratrol was found to be effective in α-AMA-induced hepatotoxicity with its anti-inflammatory properties in in vivo conditions. It is a promising compound with the potential for use in the treatment of hepatotoxicity associated with Amanita phalloides type mushroom poisonings.

Efficacy of an adenosine A1 receptor agonist compared with atropine and pralidoxime in a rat model of organophosphate poisoning

The objective of this study was to evaluate the effects of an adenosine A1 agonist, phenylisopropyl adenosine (PIA), on metamidophos poisoning compared to specific antidotes. Rats were poisoned with metamidophos (30 mg/kg, oral) and observed for 24 hours. One group received sodium chloride (1 mL/kg) and four experimental groups received atropine (5 mg/kg), pralidoxime (PAM, 20 mg/kg), atropine/PAM (5/20 mg/kg) or PIA (1 mg/kg) intraperitoneally. Atropine reduced salivation and prevented respiratory distress when compared to sodium chloride-treated rats. Treatment with PAM did not cause any suppression of cholinergic signs. Atropine and PAM combination prevented salivation, convulsion and respiratory distress. PIA delayed initial time of the salivation, convulsion and time to death. However, PIA was found ineffective against the metamidophos-induced cholinergic symptoms and mortality. All treatments, except PIA, lead to survival of these animals. Acetylcholinesterase (AChE) activity was not normalized by PIA or PAM. PIA prevented metamidophos-induced diaphragmatic muscle necrosis as much as PAM. In conclusion, a single dose of PIA was unable to protect the rats from metamidophos toxicity. Further studies are needed involving a combination of PAM and/or atropine with repeated doses of PIA to clarify the efficacy of adenosine agonists in OP poisoning.

The role of adenosine receptors and endogenous adenosine in citalopram-induced cardiovascular toxicity

Aim:

We investigated the role of adenosine in citalopram-induced cardiotoxicity.

Materials and Methods:

Protocol 1: Rats were randomized into four groups. Sodium cromoglycate was administered to rats. Citalopram was infused after the 5% dextrose, 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX; A₁ receptor antagonist), 8-(-3-chlorostyryl)-caffeine (CSC; A_2a receptor antagonist), or dimethyl sulfoxide (DMSO) administrations. Protocol 2: First group received 5% dextrose intraperitoneally 1 hour prior to citalopram. Other rats were pretreated with erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA; inhibitor of adenosine deaminase) and S-(4-Nitrobenzyl)-6-thioinosine (NBTI; inhibitor of facilitated adenosine transport). After pretreatment, group 2 received 5% dextrose and group 3 received citalopram. Adenosine concentrations, mean arterial pressure (MAP), heart rate (HR), QRS duration and QT interval were evaluated.

Results:

In the dextrose group, citalopram infusion caused a significant decrease in MAP and HR and caused a significant prolongation in QRS and QT. DPCPX infusion significantly prevented the prolongation of the QT interval when compared to control. In the second protocol, citalopram infusion did not cause a significant change in plasma adenosine concentrations, but a significant increase observed in EHNA/NBTI groups. In EHNA/NBTI groups, citalopram-induced MAP and HR reductions, QRS and QT prolongations were more significant than the dextrose group.

Conclusions:

Citalopram may lead to QT prolongation by stimulating adenosine A₁ receptors without affecting the release of adenosine.

Inhibitory effect of adenosine on intimal hyperplasia and proliferation of smooth muscle cells in a carotid arterial anastomosis animal model

PURPOSE

The effect of adenosine (9-β-0-ribifuranosyladenine) on the endothelial cell proliferation and neointimal hyperplasia is investigated in the rabbit carotid artery anastomosis model.

METHODS

Twenty-eight New Zealand white rabbits were arranged in four groups of seven animals each. The right carotid arteries of each animal were transsected and re-anastomosed. The left sides remained as control. In Group A, no medication was used. In Group B, subcutaneous Adenosine was applied for 3 days. In Group C, the same dose was applied for 7 days, and in Group D for 21 days. After 28 days, the luminal diameters, luminal areas, intima/media ratios were all measured by using histopathological evaluation.

FINDINGS

The mean luminal diameters and areas of the four groups were smaller than the control ones. Massive thickening of smooth muscle cell proliferation and dense intensifying in the connecting tissues were observed most prominently in Group A, in decreasing degrees within other groups. Intima/media ratio was highest in Group A. Scoring the quantity of e-NOS positive staining also revealed a significant difference between the experimental groups and their control associates.

CONCLUSION

The process of endothelial cell proliferation and neointimal hyperplasia can be significantly reduced by the use of adenosine.

The role of adenosine receptors on amitriptyline-induced electrophysiological changes on rat atrium

We investigated the role of adenosine receptors in amitriptyline-induced cardiac action potential (AP) changes in isolated rat atria. In the first group, APs were recorded after cumulative addition of amitriptyline (1 μM, 10 μM and 50 μM). In other groups, each atrium was incubated with selective adenosine A1 antagonist (8-cyclopentyl-1,3-dipropylxanthine (DPCPX), 10−4 M) or selective adenosine A2a receptor antagonist (8-(3-chlorostyryl) caffeine, 10−5 M) before amitriptyline administration. Resting membrane potential, AP amplitude (APA), AP duration at 50% and 80% of repolarization (APD50 and APD80, respectively), and the maximum rise and decay slopes of AP were recorded. Amitriptyline (50 μM) prolonged the APD50 and APD80 ( p < 0.001) and the maximum rise slope of AP was reduced by amitriptyline ( p < 0.0001). Amitriptyline reduced maximum decay slope of AP only at 50 μM ( p < 0.01). DPCPX significantly decreased the 50-μM amitriptyline-induced APD50 and APD80 prolongation ( p < 0.001). DPCPX significantly prevented the effects of amitriptyline (1 μM and 50 μM) on maximum rise slope of AP ( p < 0.05). DPCPX significantly prevented the amitriptyline-induced (50 μM) reduction in maximum decay slope of AP ( p < 0.001). The selective adenosine A1 receptor antagonist prevented the electrophysiological effects of amitriptyline on atrial AP. A1 receptor stimulation may be responsible for the cardiovascular toxic effects produced by amitriptyline.

Effects of BQ-788 on amitriptyline-induced cardiovascular toxicity

Objective:

We investigated both the effects of the endothelin type B (ETB) receptor antagonist, BQ-788, on amitriptyline-induced cardiotoxicity and the role of ETB receptors on amitriptyline-induced cardiovascular depression.

Methods:

Male Wistar rats were anaesthetized with urethane/chloralose. Mean arterial pressure (MAP), heart rate (HR) and QRS duration were recorded. Toxicity was induced by amitriptyline infusion (0.94 mg/kg per min) until the 50% inhibition of MAP. In the first protocol, 5% dextrose or BQ-788 bolus was administered to control or experimental group animals, respectively. In the second protocol, after incubation with BQ-788 or 5% dextrose, amitriptyline was infused.

Results:

Amitriptyline caused a significant decrease in MAP, prolonged QRS duration and decreased HR for both the groups. BQ-788 administration improved MAP (5, 10 and 15 min), shortened the prolonged QRS (5 and 10 minutes) and increased HR (5, 10 and 15 min) compared with dextrose group. While all the amitriptyline-infused rats survived in BQ-788 group, all the amitriptyline-infused rats died within 20 min in dextrose group. In the second protocol, BQ-788 incubation did not cause any statistically significant change in amitriptyline-induced cardiovascular depression.

Conclusion:

BQ-788 may have beneficial effects in amitriptyline-induced cardiovascular changes via a physiologic antagonism. ETB receptor antagonists may be the promising antidotes for the cardiovascular toxicity with hypotension and bradycardia.

Adenosine-mediated cardiovascular toxicity in amitriptyline-poisoned rats

We investigated the contribution of endogenous adenosine to amitriptyline-induced cardiovascular toxicity in rats. A control group of rats was pretreated with intraperitoneal (i.p.) 5% dextrose and received intravenous 0.94 mg/kg/min of amitriptyline for 60 minutes. The second and third groups of rats pretreated with i.p. 10 mg/kg of erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA), an adenosine deaminase inhibitor, and i.p. 1 mg/kg of S-(4-nitrobenzyl)-6-thioinosine (NBTI), a facilitated adenosine transport inhibitor, received 5% dextrose and amitriptyline infusion, respectively. Outcome parameters were mean arterial pressure (MAP), heart rate (HR), QT and QRS durations, and plasma adenosine concentrations. Plasma adenosine concentrations were increased in all groups. In the control group, amitriptyline decreased MAP and HR and prolonged QT and QRS durations after 10 minutes of infusion. In EHNA/NBTI-pretreated rats, amitriptyline prolonged QRS duration at 10 and 20 minutes. In EHNA/NBTI pretreated rats, amitriptyline-induced MAP, HR reductions, and QRS prolongations were more significant than that of dextrose-infusion-induced changes. Our results indicate that amitriptyline augmented the cardiovascular effects of endogen adenosine by increasing plasma levels of adenosine in rats.

Effects of terlipressin in a rat model of severe uncontrolled hemorrhage via liver injury

BACKGROUND

Animal experiments and clinical studies have shown that vasopressin infusion in cases of uncontrolled hemorrhagic shock is a promising treatment. However, there are only a few studies regarding the application of terlipressin in hemorrhagic cases. This study was designed to evaluate the effects of terlipressin vs controlled fluid resuscitation on hemodynamic variables and abdominal bleeding in a rat model of uncontrolled hemorrhage via liver injury.

METHODS

A total of 21 average weight 250 ± 30 g Wistar rats were used. A midline celiotomy was performed, and approximately 65% of the median and left lateral lobes were removed with sharp dissection. After creation of the liver injury, rats were randomized into 1 of 3 resuscitation groups, the control group, Lactated Ringer's (LR) group, and terlipressin group, with 7 rats in each group. Blood samples were taken from rats for arterial blood gas analysis. At the end of the experiments, free intraperitoneal blood was collected on preweighed pieces of cotton, and the amount of free blood was determined by the difference in wet and dry weights.

RESULTS

In response to resuscitation, the terlipressin group demonstrated a significant elevation in mean arterial pressure (MAP). Blood loss was greater in the LR group compared with the control group (12.8 ± 1.9 mL vs 8.2 ± 0.7 mL, P < .05). At the end of the experiments, 5 rats in the control group, 5 in the LR group, and 2 in the terlipressin group died. The average survival rates were 28.6%, 28.6%, and 71.4%, respectively.

CONCLUSIONS

Compared with the control group, intravenous terlipressin bolus after liver injury contributed to an increase in MAP and survival rates without increasing abdominal bleeding.

Is serum S100B protein a biomarker for amitriptyline-induced cardiovascular toxic effects?

The aim of this study was to assess the role of serum S100B protein as a biomarker for cardiovascular effects in an anesthetized rat model of amitriptyline toxicity. Adult male Wistar rats (n = 28) were randomized into four groups. While the control group received normal saline, the experimental groups received different doses of amitriptyline (0.625 or 0.94 or 1.25 mg/kg/min) infusion. Mean arterial pressure (MAP), heart rate (HR), electrocardiogram parameters, and serum S100B protein levels were recorded during the experiment. Linear Pearson's correlation coefficient was used to examine the association between cardiovascular parameters and serum levels of S100B protein. In the experimental groups, amitriptyline caused a significant decrease in MAP and HR (P < 0.001), a prolongation in QRS duration and QT intervals (P < 0.01), but it did not change PR intervals significantly. At the end of the experiment of the second group, a significant correlation was found between HR and serum S100B protein levels (r = -0.963, P = 0.037). At the end of the experiment of the third and fourth groups, a significant correlation between MAP, HR, all ECG parameters, and serum S100B protein levels was found. Serum S100B protein levels correlate well with amitriptyline-induced cardiovascular toxicity and can be used as a biomarker for predicting cardiovascular toxic effects of amitriptyline.

Evaluation of caustics and household detergents exposures in an emergency service

OBJECTIVE

The aim of this study was to analyse the caustic and household detergent exposure cases were admitted to the Department of Emergency Medicine at Dokuz Eylul University Hospital (EMDEU) between 1993 and 2008.

METHODS

Age, sex, reason of exposure, clinical signs, rate of endoscopy in oral exposures, treatment attempts, length of hospital stay and outcome were evaluated. A chi-square test was used to analyse statistical differences.

RESULTS

Caustic exposures accounted for 8.5% (1160 cases) and 4.1% (1988 cases) of all poisonings in children and adults, respectively. Female/male ratio of caustic exposure poisonings was 0.8. Most of the exposures were unintentional (158, 86.8%). Intentional exposures were common in cases between 19 and 29 years old (χ(2) = 25.685, p < 0.001). The most common caustic substance was alkaline (106, 58.3%) followed by acidic (47, 25.8%) and other household detergents (28, 15.4%). Vomiting (35.7%), nausea (14.8%) and sore throat (13.1%) were the most common clinical signs. The patients who had endoscopy, the most frequent finding was first-degree damage (58.7%). A 48-year-old man died from intentional hydrochloric acid ingestion.

CONCLUSION

Because of the large number of unintentional caustic exposures, parent education is very important to decrease the caustic exposures in children.

Cardiovascular medication exposures and poisonings in Izmir, Turkey: A 14-year experience

Cardiovascular medications (CVMs) are frequently prescribed for cardiovascular diseases. The unconscious use of cardiovascular drugs may lead to severe clinical manifestations, even to death, especially when in overdose. The objective of this study is to clarify the profile of CVM exposures admitted to Department of Emergency Medicine in Dokuz Eylul University Hospital (EMDEU) between 1993 and 2006. Case demographics, type of the medication, route and reason for exposure, clinical effects and outcome were recorded. Related to the CVM exposures, 105 poisoning cases were admitted. Mean age of children and adults were 12.8 ± 1.0 and 30.1 ± 1.8, respectively. Females were dominating (77.1%). Poisoning by accident occurred mainly among children in the 0—6 age group (64.3%) and suicide attempt was predominant in the 19—29 age group (47.8%). The most common ingested CVMs admitted to EMDEU were calcium channel blockers (19.7%), beta-blockers (17.3%), angiotensin converting enzyme inhibitors and diuretics (11.8%). Most of the patients were asymptomatic (59.1%). Frequently observed symptom was altered consciousness (18.6%). Antihypertensive drugs are responsible for the most of the CVM exposures. Prospectively designed multi-centered studies are needed to reflect the epidemiological properties of cardiovascular drug exposures throughout our country and would be very valuable for the determination of preventive measures.

Effect of glucagon on amitriptyline-induced cardiovascular toxicity in rats

The aim of this study was to investigate the effect of glucagon on cardiovascular parameters in anesthetized rat model of tricyclic antidepressant overdose. Toxicity was induced by infusion of amitriptyline 0.94 mg/kg/min until a 40–45% of reduction in mean arterial pressure was observed. Amitriptyline infusion rats were then randomized into three groups. Control group of rats (group 1) received a bolus of 5% dextrose followed by the continuous infusion of dextrose, whereas treatment groups received 1 mg/kg (group 2) or 2 mg/kg (group 3) bolus doses of glucagon followed by continuous infusion (0.1 mg/kg/min) of glucagons for 60 min. Mean arterial pressure, heart rate, and electrocardiogram were recorded. Amitriptyline caused a significant decrease in mean arterial pressure and a prolongation in QRS, yet it did not change the heart rate. High-bolus dose of glucagon (2 mg/kg) followed by glucagon infusion significantly increased mean arterial pressure at 40, 50, and 60 min ( P < 0.05) and shortened the prolonged QRS at 50 and 60 min ( P < 0.05) when compared with control group. There was also a significant increase in heart rate. In conclusion, bolus doses followed by a continuous infusion of glucagon were found to be effective in reversing the hypotension and QRS prolongation in the rat model of amitriptyline toxicity. Further studies are needed to reveal the exact mechanism of the proposed effect.

A retrospective evaluation of analgesic exposures from Izmir, Turkey

The objective of this study is to analyze exposures concerning analgesics that were reported to Dokuz Eylul University Drug and Poison Information Center (DPIC) and admitted to the Department of Emergency Medicine in Dokuz Eylul University Hospital (EMDEU) between 1993 and 2004. Demographics of the patients, characteristics of analgesic exposures, performed treatment attempts and outcome of the poisoned patients were recorded on standard data forms and were then entered into a computerized database program. Statistical analysis was performed by using the chi-square test. The DPIC recorded 55 962 poisoning calls, 48 654 (86.9%) of them related to medicines. Analgesics accounted for 16.3% (7 939 cases) of all medicine-related exposures; among them 446 exposures were admitted to EMDEU. More than half of the analgesic exposure calls and admitted cases involved adults (55.9%, 4 440). Females dominated in all age groups (70.3%, 5 578). Mean age was 20.2 +/- 11.8. The most involved analgesics were paracetamol (47.9%), propionic acid derivatives (16.1%) and salicylates (13.7%). Most of the poisonings were intentional (75.1%), especially in 19-29 years age group of adults and 13-18 years age group of children. Most of the patients reported to DPIC and admitted to EMDEU were asymptomatic (84.4% and 54.7%, respectively). Gastrointestinal decontamination methods were performed more frequently for admitted poisoning cases before hospital admission than reported poisoning cases (61% vs. 23%). Paracetamol ingestion was the most common cause of analgesic exposures reported to our DPIC. Most of the analgesic exposures reported to DPIC were asymptomatic or mild. DPICs have an important role for the referral of analgesic exposures without unnecessary gastrointestinal decontamination procedures.

Effects of adenosine receptor antagonists on amitriptyline-induced vasodilation in rat isolated aorta

BACKGROUND

Although we have previously demonstrated the beneficial effects of adenosine receptor antagonists in preventing cardiovascular toxicity of amitriptyline in rats, it is not clear whether adenosine receptors in heart or in vasculature are dominant. The aim of the current study was to investigate the role of adenosine A(2a) receptors on amitriptyline-induced vasodilation in rat isolated aorta.

METHODS

After determining EC(80) of noradrenalin (NA) (the concentration of noradrenalin that produces 80% of maximal contractile response) as 10(-5)M, the IC(50) value of amitriptyline was measured in rat isolated aorta (the drug concentration causing a half- maximal inhibition of contractile responses to NA); IC(50) of amitriptyline was then compared in the presence of the DPCPX (a selective adenosine A(1) antagonist), CSC (a selective A(2a) antagonist) or DMSO (a solvent for adenosine antagonists). Statistical analysis was done using the Student t test.

RESULTS

Amitriptyline-inhibited 49.9 +/- 3.7 % contractile response to NA on aorta segments at 1.8 x 10(-5)M (IC(50)). While DPCPX increased amitriptyline-induced inhibition on contractile response to NA dose dependently, CSC decreased the contractile response to NA only at 10(-5)M. DMSO did not change amitriptyline-induced IC(50).

CONCLUSION

Adenosine A(2a) receptor stimulation seems to be responsible partly for amitriptyline-induced vasodilation and hypotension since the adenosine A(1) antagonist, DPCPX, increased amitriptyline-induced vasodilation in rat isolated aorta.

Effect of subacute methyl parathion administration on the pharmacokinetics and pharmacodynamics of nifedipine in rats

Families living in agricultural areas may submitted to repeated exposure of methyl parathion (MP) that has been widely used as an agricultural insecticide. MP inhibits cytochrome P450 enzymes and has the potential to alter pharmacokinetic profiles of therapeutic agents that are metabolized in the liver. The aim of the present study is to investigate the possibility that the increased pharmacokinetic and pharmacodynamic effects of nifedipine is due to the inhibition of the metabolism after repeated administration of low doses of MP in rats. Male rats received commercial formulation of diluted MP (1/100 LD(50) or 1/25 LD(50), n=6) or tap water (control, n=5) via gastric gavage (0.5ml) for 14 days. On the 15th day, the carotid artery and jugular vein were cannulated for measurement of cardiovascular parameters and blood sampling, respectively. Nifedipine was administered 3mg/kg via the cannula inserted in the duodenum of the rat. Subacute MP administration did not change pharmacokinetic AUC((0-240)), C(max), t(max), t(1/2)) and pharmacodynamic (mean arterial pressures and heart rates) parameters of nifedipine. These findings provide evidence that repeated exposure of low doses of commercial MP did not affect the elimination of nifedipine which might be due to the lack of inhibition of CYP3A in rats.

First-order and second-order statistical analysis of 3D and 2D image structure

In the first part of this article, we analyze the relation between local image structures (i.e., homogeneous, edge-like, corner-like or texture-like structures) and the underlying local 3D structure (represented in terms of continuous surfaces and different kinds of 3D discontinuities) using range data with real-world color images. We find that homogeneous image structures correspond to continuous surfaces, and discontinuities are mainly formed by edge-like or corner-like structures, which we discuss regarding potential computer vision applications and existing assumptions about the 3D world. In the second part, we utilize the measurements developed in the first part to investigate how the depth at homogeneous image structures is related to the depth of neighbor edges. For this, we first extract the local 3D structure of regularly sampled points, and then, analyze the coplanarity relation between these local 3D structures. We show that the likelihood to find a certain depth at a homogeneous image patch depends on the distance between the image patch and a neighbor edge. We find that this dependence is higher when there is a second neighbor edge which is coplanar with the first neighbor edge. These results allow deriving statistically based prediction models for depth interpolation on homogeneous image structures.