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.

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.

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 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.

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.

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.

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.

Vasorelaxant effect of iloprost on isolated human internal mammary artery

In this study, vasodilator effect of iloprost on KCl-induced contraction in human internal mammary artery (IMA) was studied and compared with other vasodilators papaverin and diltiazem. Ring segments of IMA were studied in organ baths for measurement of isometric tension. After the tissues has reached their baseline tension, precontraction was induced by 100 mm KCl and cumulative concentration-relaxation was measured by the application of iloprost (10(-9)-10(-6) m), papaverine (10(-5)-10(-4) m), diltiazem (10(-9)-10(-4) m) or ethanol; a solvent for iloprost; alone. The maximal relaxation of IMA segments to iloprost was 13.5 +/- 2.2%. Iloprost caused significantly limited relaxation when compared with papaverin (106.0 +/- 2.9%) and diltiazem (93.6 +/- 2.5%) (P < 0.001). Papaverin produced the greatest maximal relaxation to KCl-induced contraction of IMA. The potency of iloprost (-log EC(50) = 6.59 +/- 0.19) was significantly higher than those of papaverine (-log EC(50) = 4.21 +/- 0.11) and diltiazem (-log EC(50) = 5.63 +/- 0.06) (P < 0.001). In addition, -log EC(50) of diltiazem was significantly greater than papaverin (P < 0.001). Iloprost appears to be more potent than those of papaverine and diltiazem but it was inefficient in maximal inhibition on KCl-induced contraction. Iloprost may have little benefit in KCl-related vasoconstriction on human IMA segments.

Interrelation between the Poisoning Severity Score, carboxyhaemoglobin levels and in-hospital clinical course of carbon monoxide poisoning

The aim of the present study is to evaluate the relationship between the Poisoning Severity Score (PSS) and carboxyhaemoglobin (COHb) levels in patients with carbon monoxide poisoning (COP) using outcome as the measure. The study was designed as a retrospective chart review of patients with final diagnosis of COP. Correlation of PSS and COHb levels at presentation was evaluated with collected data. Majority of the cases were grade 1 (minor) PSS (134 cases, 73.6%) and 93.4% of these patients made a complete recovery. There were six deaths (mortality 3.3%) and six in-hospital major complications (IHMCs) (3.3%) (please specify whether the complications were in the patients who died). There is moderate correlation between PSS and outcome (p < 0.001, r = 0.493). Grade 3 (severe) PSS was significantly different from other grades for outcome (six mortalities and three IHMCs). Patients classified as grade 3 and patients who died had a significantly higher mean age (p < 0.05, 41.8 +/- 23.6 and p < 0.01, 60.1 +/- 20.3, respectively). Mean COHb level of grade 3 (33.2 +/- 13.9%) was significantly higher than that of other grades (p < 0.05). COHb levels according to outcome were not different (? within the patients in grade 3). Decreased level of consciousness, acidosis, tachycardia, high glucose and leucocyte levels showed significant relation with higher PSS, COHb level and adverse outcome. We conclude that the PSS is a reliable guide in COP. Value of the PSS in COP may be enhanced if additional factors and investigations are included.

Local image structures and optic flow estimation

Different kinds of local image structures (such as homogeneous, edge-like and junction-like patches) can be distinguished by the intrinsic dimensionality of the local signals. Intrinsic dimensionality makes use of variance from a point and a line in spectral representation of the signal in order to classify it as homogeneous, edge-like or junction-like. The concept of intrinsic dimensionality has been mostly exercised using discrete formulations; however, recent work has introduced a continuous definition. The current study analyzes the distribution of local patches in natural images according to this continuous understanding of intrinsic dimensionality. This distribution reveals specific patterns than can be also associated to local image structures established in computer vision and which can be related to orientation and optic flow features. In particular, we link quantitative and qualitative properties of optic-flow error estimates to these patterns. In this way, we also introduce a new tool for better analysis of optic flow algorithms.

Diffusion-weighted MR imaging of pleural fluid: differentiation of transudative vs exudative pleural effusions

The aim of this study was to evaluate the ability of diffusion-weighted MRI in differentiating transudative from exudative pleural effusions. Fifty-seven patients with pleural effusion were studied. Diffusion-weighted imaging (DWI) was performed with an echo-planar imaging (EPI) sequence (b values 0, 1000 s/mm(2)) in 52 patients. The apparent diffusion coefficient (ADC) values were reconstructed from three different regions. Subsequently, thoracentesis was performed and the pleural fluid was analyzed. Laboratory results revealed 20 transudative and 32 exudative effusions. Transudates had a mean ADC value of 3.42+/-0.76 x 10(-3) mm(2)/s. Exudates had a mean ADC value of 3.18+/-1.82 x 10(-3) mm(2)/s. The optimum cutoff point for ADC values was 3.38 x 10(-3) mm(2)/s with a sensitivity of 90.6% and specificity of 85%. A significant negative correlation was seen between ADC values and pleural fluid protein, albumin concentrations and lactate dehydrogenase (LDH) measurements ( r=-0.69, -0.66, and -0.46, respectively; p<0.01). The positive predictive value, negative predictive value, and diagnostic accuracy of ADC values were determined to be 90.6, 85, and 88.5%, respectively. The application of diffusion gradients to analyze pleural fluid may be an alternative to the thoracentesis. Non-invasive characterization of a pleural effusion by means of DWI with single-shot EPI technique may obviate the need for thoracentesis with its associated patient morbidity.

The effects of captopril on serum digoxin levels in patients with severe congestive heart failure

The effects of captopril on serum digoxin concentrations were studied in 8 patients with severe (NYHA Class IV) congestive heart failure. Serum digoxin concentrations were determined before and after the administration of captopril for 1 week in patients on chronic digoxin therapy. Each patient who was taking 0.25 mg of digoxin PO q.d., was administered 12.5 mg of captopril PO t.i.d. for 7 days. The peak serum concentration of digoxin (Cmax) before and after (on Days 0 and 7) captopril administration was 1.7+/-0.2 ng/ml and 2.7+/-0.2 ng/ml, the time to peak (tmax) was 2.4+/-0.5 h and 1.3+/-0.2 h, and the area under the 24-hour digoxin concentration-time curve (AUC0-24h) was 30.0+/-1.5 ng x h/ml and 41.7+/-3.4 ng x h/ml, respectively. While captopril caused a significant increase in peak serum concentration and the area under the digoxin concentration-time curve, it decreased the time to digoxin peak (p = 0.01, p = 0.04, p = 0.01, respectively). No patient developed evidence of digoxin toxicity. Concomitant administration of captopril with digoxin increases serum digoxin concentration in patients with severe congestive heart failure.

Effects of subchronic parathion exposure on cyclosporine pharmacokinetics in rats

Parathion undergoes enzymatic oxidation by hepatic cytochrome P-450 (CYP450) enzymes to the active metabolite paraoxon. Consequently, alterations in CYP450-dependent oxidation may affect the pharmacokinetics and pharmacodynamics of drugs that are metabolized in the liver. The CYP3A family is known to be responsible for the majority of cyclosporine metabolism. The aim of the present study was to assess the disposition kinetics of cyclosporine during subchronic parathion exposure. Male Wistar rats were administered either water or two different doses of parathion (1/100 LD50, 1/25 LD50; LD50 = 14 mg/kg) by gavage for 6 wk. Subsequently, rats in each experimental group received a single oral dose of cyclosporine (10 mg/kg), and serial blood samples were drawn from the carotid artery over a period of 48 h. Pharmacokinetic analysis showed that parathion increased the blood cyclosporine concentration twofold as evidenced by AUC (area under the curve), half life (t 1/2) and peak plasma concentration (Cmax). This may be due to inhibition of cyclosporine metabolism, an interaction that may be of clinical relevance in immunosuppression therapy.

The effects of propofol on normal and hypercholesterolemic isolated rabbit heart

The aim of the present study was to compare the effects of propofol on cardiac contractile force in normal and hypercholesterolemic isolated rabbit hearts. While one group was fed with standard chow pellets (150 g/day), the other group received cholesterol (1% w/w) in addition to the same amount of rabbit chow pellets during 1 month. Hearts from standard-fed rabbits were given intralipid solvent or 25, 50 and 100 microM propofol by infusion. Hypercholesterolemic rabbit hearts were administered 25, 50 and 100 microM propofol by infusion. All concentrations of propofol did not result in any significant change of the heart rates (HR) in two groups. Propofol (25, 50 and 100 microM) infusion induced a concentration- and time-dependent inhibition in left ventricular pressure (LVP) in standard chow diet group (P<.05,.05 and.05, respectively). In hypercholesterolemic rabbit hearts, 25 and 50 microM propofol infusion developed a significant inhibition in LVP when compared with the standard chow diet group (P<.05 and.05, respectively). Propofol (100 microM) infusion developed a significant increase in LVP after 20 min in hypercholesterolemic rabbit hearts when compared with normal rabbit hearts (P<.05). Supratherapeutic concentration of propofol might have cardioprotective effect on hypercholesterolemic rabbit hearts.

Effect of verapamil on responses to endothelin-1 in aortic rings from streptozotocin-induced diabetic rats

In this study, we investigated the constrictor responsiveness to endothelin-1 (ET-1, 10-30 n m) of aortic rings (under 1 g resting tension in Krebs-Bicarbonate solution) from 8-weeks streptozotocin (STZ, 65 mg kg-1, i.p)-induced diabetic rats and vehicle-treated control rats. The maximum ET-1-induced contraction of the aorta in diabetic rats was increased by 150%, but the EC50 of ET-1 remained unchanged. Although in both groups, verapamil reduced the constrictor responses to ET-1 (diabetic group P<0.001, control group P<0.05), there were not any significant differences between PD2 values. These results suggest that verapamil inhibits ET-1-induced Ca2+ entry through the L-type channel and this effect did not change in diabetes mellitus.

Midazolams cardiac depressant effects and their lack of reversal by flumazenil in isolated rabbit hearts

Midazolam is known to cause a dose-dependent increase and decrease in the contractile force of the myocardium. Whether flumazenil can reverse these effects of midazolam remains unclear. In this study, we determined the cardiac effects of midazolam and the counter effect of flumazenil on midazolam-induced myocardial depression in isolated rabbit hearts. Rabbit hearts were isolated and perfused using the Langendorff technique, and left ventricle pressure and heart rate were measured by a pressure transducer in the left ventricle. One set of hearts were perfused with increasing concentrations of midazolam for 10 min, another set were perfused with concomitant midazolam and flumazenil. Concentrations of 5, 10, 20 and 50 microM midazolam decreased left ventricle pressure significantly (P < 0.01, P < 0.05, P < 0.01, P < 0.01, respectively). Heart rates decreased with concentrations of 10, 20 and 50 microM midazolam (P < 0.01, P < 0.01, P < 0.05, respectively). Flumazenil had no effect on the midazolam-induced decrease in left ventricle pressure and heart rate. Midazolam decreased the cardiac contractile force and heart rate of isolated rabbit hearts in a concentration-dependent manner. The failure of flumazenil to reverse these effects suggest that this cardiac depressant effect of midazolam is not mediated through peripheral benzodiazepine receptors.

Relationship between high serum digoxin levels and toxicity

A retrospective study of 1,269 patients on digoxin was done to determine the relationship between serum digoxin levels of 3.0 ng/ml or higher and clinical toxicity. Of 1,269 patients, 58 (4.6%) had digoxin serum levels of 3.0 ng/ml or higher. Clinical evidence of digoxin toxicity was present in only 11 of these patients and premature blood sampling accounted for the high levels in 10 other nontoxic patients. None of the patients with clinical toxicity died. The other 37 patients tolerated the high digoxin levels without exhibiting toxic effect. Low cardiac output, concomitant use of other drugs, and impaired renal function increased the serum digoxin levels in patients with and without clinical toxicity. Appropriate therapeutic digoxin level monitoring and confirmatory laboratory-clinical relationship may have important influences on these results. Additional work on further definition of "toxic" digoxin levels needs to be performed.

The effects of amrinone and glucagon on verapamil-induced cardiovascular toxicity in anaesthetized rats

The goal of this study was to compare the effects of glucagon and amrinone on mean arterial pressure (MAP) and heart rate, when used alone and in combination, in an anaesthetized rat model of verapamil toxicity. Rats were anaesthetized and the carotid artery was cannulated for MAP and heart rate measurements. Jugular and femoral veins were cannulated for drug administration. After verapamil infusion (15 mg/kg/h), control animals were given normal saline solution and the other groups received amrinone (0.1 or 0.2 mg/kg/min), glucagon (0.3 mg/kg bolus followed by 0.1 or 0.2 mg/ kg/min infusion), glucagon plus amrinone (0.1 mg/kg/min and 0.1 mg/kg/min respectively) or glucagon plus amrinone (0.2 mg/kg/min and 0.1 mg/kg/min respectively). Glucagon (0.2 mg/kg/min) significantly increased MAP when compared to the control group (P < 0.01). The combination of glucagon and amrinone did not produce a synergistic effect for the recovery of MAP. Furthermore, this combination masked the positive effects of glucagon (0.2 mg/kg/min) on MAP. Glucagon (0.2 mg/kg/min) increased the heart rates compared with those of the control group (P < 0.05). Additionally, amrinone (0.1 mg/kg/min) plus glucagon (0.1 mg/kg/min) increased the heart rates (P < 0.05). Finally, glucagon dose dependently recovered MAP. While amrinone depressed MAP in combination with glucagon, it did not alter the positive chronotropic effect of high dose glucagon.

The effect of acute bilateral adrenalectomy on serotonin-induced inhibition of gastric acid secretion and acute gastric mucosal injury in rats

Serotonin (5-hydroxytryptamine, 5-HT) produces many changes in gastric functional parameters, including the inhibition of gastric acid secretion and changes in mucosal blood flow. Exogenous 5-HT has also been shown to induce gastric erosion. The influence of adrenalectomy on experimental lesions in the rat gastric mucosa remains controversial. The aim of this study was to see the effects of adrenalectomy on pentagastrin stimulated gastric acid secretion in anaesthetized male Wistar rats. Gastric acid was collected via cannulae placed in the stomach. 5-HT (3.5 mumol/kg, i.v.) inhibited pentagastrin stimulated acid output by 54% and produced haemorrhagic gastric lesions with a mean ulcer index of 2 +/- 0.3. Adrenalectomy prevented both 5-HT induced inhibition of gastric acid secretion and mucosal injury. The results suggest that the effects of 5-HT require an intact adrenal gland.