Acute coronary syndrome associated cardiogenic shock in the catheterization laboratory: peripheral veno-arterial extracorporeal membrane oxygenator management and recommendations.

Cardiogenic shock (CS) in acute coronary syndrome (ACS) is a critical disease with high mortality rates requiring complex treatment to maximize patient survival chances. Emergent coronary revascularization along with circulatory support are keys to saving lives. Mechanical circulatory support may be instigated in severe, yet still reversible instances. Of these, the peripheral veno-arterial extracorporeal membrane oxygenator (pVA-ECMO) is the most widely used system for both circulatory and respiratory support. The aim of our work is to provide a review of our current understanding of the pVA-ECMO when used in the catheterization laboratory in a CS ACS setting. We detail the workings of a Shock Team: pVA-ECMO specifics, circumstances, and timing of implantations and discuss possible complications. We place emphasis on how to select the appropriate patients for potential pVA-ECMO support and what characteristics and parameters need to be assessed. A detailed, stepwise implantation algorithm indicating crucial steps is also featured for practitioners in the catheter laboratory. To provide an overall aspect of pVA-ECMO use in CS ACS we further gave pointers including relevant human resource, infrastructure, and consumables management to build an effective Shock Team to treat CS ACS via the pVA-ECMO method.

Comparison of Safety of RADial comPRESSion Devices: A Multi-Center Trial of Patent Hemostasis following Percutaneous Coronary Intervention from Conventional Radial Access (RAD-PRESS Trial).

Although radial access is the current gold standard for the implementation of percutaneous coronary interventions (PCI), post-procedural radial compression devices are seldom compared with each other in terms of safety or efficacy. Our group aimed to compare a cost effective and potentially green method to dedicated radial compression devices, with respect to access site complications combined in a device oriented complex endpoint (DOCE), freedom from which served as our primary endpoint. Patients undergoing PCI were randomized to receive either the cost effective or a dedicated device, either of which were removed using patent hemostasis. Twenty-four hours after the procedure, radial artery ultrasonography was performed to evaluate the access site. The primary endpoint was assessed using a non-inferiority framework with a non-inferiority margin of five percentage points, which was considered as the least clinically meaningful difference. The cost-effective technique and the dedicated devices were associated with a comparably low rate of complications (freedom from DOCE: 83.3% vs. 70.8%, absolute risk difference: 12.5%, one-sided 95% confidence interval (CI): 1.11%). Composition of the DOCE (i.e., no complication, hematoma, pseudoaneurysm, and radial artery occlusion) and compression time were also assessed in superiority tests as secondary endpoints. Both the cost-effective technique and the dedicated devices were associated with comparably low rates of complications: p = 0.1289. All radial compression devices performed similarly when considering the time to complete removal of the respective device (120.0 (inter-quartile range: 100.0-142.5) for the vial vs. 120.0 (inter-quartile range: 110.0-180) for the dedicated device arm, with a median difference of [95% CI]: 7.0 [-23.11 to 2.00] min, p = 0.2816). In conclusion, our cost-effective method was found to be non-inferior to the dedicated devices with respect to safety, therefore it is a safe alternative to dedicated radial compression devices, as well as seeming to be similarly effective.

Severe exacerbations and mortality in COPD patients: A retrospective analysis of the database of the Hungarian National Health Insurance Fund.

INTRODUCTION: COPD is one of the most common pulmonary diseases and one of the leading causes of death worldwide. Exacerbations of COPD include acute worsening that could lead to hospitalization and death. In this study, our objective was to investigate the natural course of moderate and severe exacerbations (SAE) and mortality in the Hungarian population in the past decade. METHODS: A retrospective financial database analysis was performed to examine the risk of additional SAEs and death after the first ever SAE in COPD patients, using the financial database of the Hungarian National Health Insurance Fund (NHIF). Patients were enrolled between 2009.01.01. and 2019.12.31. if they had received at least one inhaled drug (LABA, LAMA, ICS or SABA/SAMA) and had been hospitalized for a COPD exacerbation (ICD-10 code J44). RESULTS: A total of 63,037 patients with COPD were enrolled after their first SAE. Of them, 27,095 patients suffered at least one subsequent SAE, and 32,120 patients died during the 10-year follow-up. The median survival was 4.7 years. The risk of subsequent hospitalizations increased significantly after each SAE, with hazard ratios ranging from 1.65 to 5.01. The risk for mortality was increased after each SAE, but did not increase further with the number of SAEs. Moreover, the risk for subsequent SAE and death increased with moderate exacerbations; however, this risk did not increase further with each event. CONCLUSIONS: Despite a relevant improvement in COPD treatment, the natural course of exacerbations remained unchanged. This result highlights the importance of preventing exacerbations and the need for more research to better predict them.

The Design and Feasibility of the: Radial Artery Puncture Hemostasis Evaluation - RAPHE Study, a Prospective, Randomized, Multicenter Clinical Trial.

Introduction and Aim: Radial artery approach angiography is the current gold standard for coronary status diagnostics and eventual percutaneous revascularization (PCI). Currently, application of adequate, patent hemostasis based physical torniquets are used for puncture site control, to avoid bleeding, radial artery occlusion and damage (RAO and RAD). The Radial Artery Puncture Hemostasis Evaluation (RAPHE) is a prospective, randomized, multicenter clinical trial designed to investigate new, simplified techniques of radial artery hemostasis utilizing physical compression free methods. Methods and Results: The RAPHE study has been designed to evaluate the efficacy and safety of two non-compression based radial artery hemostasis methods: a 100% chitosan bioactive hemostatic dressing and a purpose-built radial potassium-ferrate based topical hemostasis disc. These devices will be investigated in a standalone configuration. Control group is a standard pneumatic airbladder-based compression device. A total of 600 patients will be enrolled in a three-way randomization (1:1:1) with two study and one control groups. Safety and efficacy endpoints are RAO, puncture site hematoma formation and RAD respectively, consisting of dissection, (pseudo)aneurism and/or fistula formation, measured post-procedure and at sixty days. Conclusion: The results from this trial will provide valuable information on new, simplified methods of radial artery hemostasis options and possibly simplify post-puncture management of patients. Clinical Trial Registration: [www.ClinicalTrials.gov], identifier [NCT04857385].

Interplay of Liver-Heart Inflammatory Axis and Cannabinoid 2 Receptor Signaling in an Experimental Model of Hepatic Cardiomyopathy.

BACKGROUND AND AIMS: Hepatic cardiomyopathy, a special type of heart failure, develops in up to 50% of patients with cirrhosis and is a major determinant of survival. However, there is no reliable model of hepatic cardiomyopathy in mice. We aimed to characterize the detailed hemodynamics of mice with bile duct ligation (BDL)-induced liver fibrosis, by monitoring echocardiography and intracardiac pressure-volume relationships and myocardial structural alterations. Treatment of mice with a selective cannabinoid-2 receptor (CB2 -R) agonist, known to attenuate inflammation and fibrosis, was used to explore the impact of liver inflammation and fibrosis on cardiac function. APPROACH AND RESULTS: BDL induced massive inflammation (increased leukocyte infiltration, inflammatory cytokines, and chemokines), oxidative stress, microvascular dysfunction, and fibrosis in the liver. These pathological changes were accompanied by impaired diastolic, systolic, and macrovascular functions; cardiac inflammation (increased macrophage inflammatory protein 1, interleukin-1, P-selectin, cluster of differentiation 45-positive cells); and oxidative stress (increased malondialdehyde, 3-nitrotyrosine, and nicotinamide adenine dinucleotide phosphate oxidases). CB2 -R up-regulation was observed in both livers and hearts of mice exposed to BDL. CB2 -R activation markedly improved hepatic inflammation, impaired microcirculation, and fibrosis. CB2 -R activation also decreased serum tumor necrosis factor-alpha levels and improved cardiac dysfunction, myocardial inflammation, and oxidative stress, underlining the importance of inflammatory mediators in the pathology of hepatic cardiomyopathy. CONCLUSIONS: We propose BDL-induced cardiomyopathy in mice as a model for hepatic/cirrhotic cardiomyopathy. This cardiomyopathy, similar to cirrhotic cardiomyopathy in humans, is characterized by systemic hypotension and impaired macrovascular and microvascular function accompanied by both systolic and diastolic dysfunction. Our results indicate that the liver-heart inflammatory axis has a pivotal pathophysiological role in the development of hepatic cardiomyopathy. Thus, controlling liver and/or myocardial inflammation (e.g., with selective CB2 -R agonists) may delay or prevent the development of cardiomyopathy in severe liver disease.

Prevention of the development of heart failure with preserved ejection fraction by the phosphodiesterase-5A inhibitor vardenafil in rats with type 2 diabetes.

AIMS: Heart failure with preserved ejection fraction (HFpEF) has a great epidemiological burden. The pathophysiological role of cyclic guanosine monophosphate (cGMP) signalling has been intensively investigated in HFpEF. Elevated levels of cGMP have been shown to exert cardioprotective effects in various cardiovascular diseases, including diabetic cardiomyopathy. We investigated the effect of long-term preventive application of the phosphodiesterase-5A (PDE5A) inhibitor vardenafil in diabetic cardiomyopathy-associated HFpEF. METHODS AND RESULTS: Zucker diabetic fatty (ZDF) rats were used as a model of HFpEF and ZDF lean rats served as controls. Animals received vehicle or 10 mg/kg body weight vardenafil per os from weeks 7 to 32 of age. Cardiac function, morphology was assessed by left ventricular (LV) pressure-volume analysis and echocardiography at week 32. Cardiomyocyte force measurements were performed. The key markers of cGMP signalling, nitro-oxidative stress, apoptosis, myocardial hypertrophy and fibrosis were examined. The ZDF animals showed diastolic dysfunction (increased LV/cardiomyocyte stiffness, prolonged LV relaxation time), preserved systolic performance, decreased myocardial cGMP level coupled with impaired protein kinase G (PKG) activity, increased nitro-oxidative stress, enhanced cardiomyocyte apoptosis, and hypertrophic and fibrotic remodelling of the myocardium. Vardenafil effectively prevented the development of HFpEF by maintaining diastolic function (decreased LV/cardiomyocyte stiffness and LV relaxation time), by restoring cGMP levels and PKG activation, by lowering apoptosis and by alleviating nitro-oxidative stress, myocardial hypertrophy and fibrotic remodelling. CONCLUSIONS: We report that vardenafil successfully prevented the development of diabetes mellitus-associated HFpEF. Thus, PDE5A inhibition as a preventive approach might be a promising option in the management of HFpEF patients with diabetes mellitus.

Trastuzumab cardiotoxicity: from clinical trials to experimental studies.

Epidermal growth factor receptor-2 (HER-2) is overexpressed in 20 to 25% of human breast cancers, which is associated with aggressive tumour growth and poor prognosis. Trastuzumab (Herceptin®) is a humanized monoclonal antibody directed against HER-2, the first highly selective form of therapy targeting HER-2 overexpressing tumours. Although initial trials indicated high efficacy and a favourable safety profile of the drug, the first large, randomized trial prompted a retrospective analysis of cardiac dysfunction in earlier trials utilizing trastuzumab. There has been ongoing debate on the cardiac safety of trastuzumab ever since, initiating numerous clinical and preclinical investigations to better understand the background of trastuzumab cardiotoxicity and evaluate its effects on patient morbidity. Here, we have given a comprehensive overview of our current knowledge on the cardiotoxicity of trastuzumab, primarily focusing on data from clinical trials and highlighting the main molecular mechanisms proposed. LINKED ARTICLES: This article is part of a themed section on New Insights into Cardiotoxicity Caused by Chemotherapeutic Agents. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.21/issuetoc.

Chronic plus binge ethanol feeding induces myocardial oxidative stress, mitochondrial and cardiovascular dysfunction, and steatosis.

Alcoholic cardiomyopathy in humans develops in response to chronic excessive alcohol consumption; however, good models of alcohol-induced cardiomyopathy in mice are lacking. Herein we describe mouse models of alcoholic cardiomyopathies induced by chronic and binge ethanol (EtOH) feeding and characterize detailed hemodynamic alterations, mitochondrial function, and redox signaling in these models. Mice were fed a liquid diet containing 5% EtOH for 10, 20, and 40 days (d) combined with single or multiple EtOH binges (5 g/kg body wt). Isocalorically pair-fed mice served as controls. Left ventricular (LV) function and morphology were assessed by invasive pressure-volume conductance approach and by echocardiography. Mitochondrial complex (I, II, IV) activities, 3-nitrotyrosine (3-NT) levels, gene expression of markers of oxidative stress (gp91phox, p47phox), mitochondrial biogenesis (PGC1α, peroxisome proliferator-activated receptor α), and fibrosis were examined. Cardiac steatosis and fibrosis were investigated by histological/immunohistochemical methods. Chronic and binge EtOH feeding (already in 10 days EtOH plus single binge group) was characterized by contractile dysfunction (decreased slope of end-systolic pressure-volume relationship and preload recruitable stroke work), impaired relaxation (decreased time constant of LV pressure decay and maximal slope of systolic pressure decrement), and vascular dysfunction (impaired arterial elastance and lower total peripheral resistance). This was accompanied by enhanced myocardial oxidative/nitrative stress (3-NT; gp91phox; p47phox; angiotensin II receptor, type 1a) and deterioration of mitochondrial complex I, II, IV activities and mitochondrial biogenesis, excessive cardiac steatosis, and higher mortality. Collectively, chronic plus binge EtOH feeding in mice leads to alcohol-induced cardiomyopathies (National Institute on Alcohol Abuse and Alcoholism models) characterized by increased myocardial oxidative/nitrative stress, impaired mitochondrial function and biogenesis, and enhanced cardiac steatosis.

[Retrospective analysis of short-term and mid-term results of percutaneous endovascular repair in patients with abdominal aortic aneurysm]. / Retrospektívna analýza krátkodobých a strednodobých výsledkov perkutánnej endovaskulárnej liecby pacientov s aneuryzmou abdominálnej aorty.

INTRODUCTION: Endovascular abdominal aortic aneurysm repair (EVAR) is a modern and, compared to conventional open surgery, less invasive therapeutic strategy with short-term lower morbidity and mortality. The aim of our retrospective analysis was the assessment of safety, technical success, short-term and mid-term results of elective patients scheduled for total percutaneous EVAR implantation (PEVAR). MATERIAL AND METHODS: One hundred and sixteen consecutive patients (M:F 104:12, age 71±9 years, maximum AAA diameter 60±14mm) underwent elective PEVAR between January 2009 and August 2012. All the patients were treated under local anaesthesia by total percutaneous approach via femoral access. The immediate technical success of stentgraft implantation as well as the presence of 30-day and 1-year complications and the need of reintervention rate were assessed. RESULTS: In 115/116 patients (99.1%),immediate technical success of the procedure was recorded, with no need of conversion to open surgery; in 1 patient (0.9%) the performance technically failed due to unfavourable arterial anatomy. The mortality in 30-day follow-up was 2.6% (3 patients), during 1-year follow-up it amounted to 8.6% (10 patients), without causal relationship with stentgraft implantation. Overall event-free survival was 85% (98/116) without serious complications (mortality, MI, stroke, reintervention, severe ischemic complication) in the one-year follow-up period. CONCLUSION: Endovascular AAA repair is a safe and feasible method with low mortality and acceptable complication rate in patients scheduled for EVAR implantation. Percutaneous approach allows for the extension of indications also for the highest-risk group of polymorbid patients. Technical feasibility and adequate periprocedural management are essential for further reduction in adverse events after PEVAR.

Endovascular treatment of internal carotid and vertebral artery aneurysms using a novel pericardium covered stent.

Intracranial aneurysm is a fairly common (often asymptomatic) condition. Subarachnoid hemorrhage associated with aneurysmal rupture is a potentially lethal event with a mortality rate as high as 50 percent and a high rate of disability among those who survive the initial hemorrhage, such that recently published guidelines support treatment of intracerebral aneurysms. The current treatment options include surgical clipping and endovascular treatment, but these are not without significant problems. Despite the trend toward endovascular treatment the rate of recurrence and complications is high. Current published evidence of the use of covered stent is limited to stents covered with polytetrafluoroethylene. It is now recognized that mammalian extracellular matrix represents an excellent scaffold material suitable for many therapeutic applications and glutaraldehyde treated pericardium has been widely used for many years due to its desirable features such as low immunogenicity and durability. This report describes the first published experience with the Aneugraft Pericardium Covered Stent (ITGI Medical, OR Akiva, Israel) in the treatment of internal carotid and vertebral artery aneurysms in three patients. In all three cases, the implantation of this novel device has resulted in successful closure of aneurysms.

[Successfully combined management of the abberant retroesophageal arteria subcalvia dextra aneurysm (arteria lusoria)]. / Uspesné kombinované riesenie aneuryzmy aberantnej retroezofageálne prebiehajúcej arteria subclavia dextra (arteria lusoria). Kazuistika.

INTRODUCTION: Aberrant right subclavian artery arising from the distal part of the aortic arch and passing behind the oesophagus (arteria lusoria) is a rare congenital vascular anomaly, it is the 4th most common aortic arch anomaly. At the site of the orifice there is the Kommerell's diverticulum, which is the locus minoris resistentiae with the possible arise of the aortic aneurysm. Aneurysmatic dilatation of the anomalous artery and of the aorta may be the cause of distal embolism or rupture. Less frequently there is also the possibility of aortic dissection or traumatic rupture. CASE REPORT: 54-old man with a symptomatic aberrant aneurysmatic dilated right subclavian artery (arteria lusoria) and an anerurysmatic dilatation of the Kommerell's diverticulum was indicated to staged combined management. Firstly we performed open surgical debranching of two supraaortic trunks (both subclavian arteries). Thereafter we excluded the orifice of the aberrant artery with the Kommerell's diverticulum by use of the endovascular techniques. There have been no complications during the perioperative period and the effect of surgery was optimal. DISCUSSION: It is generally accepted that the presence of aneurysm of the aberrant right subclavian artery is an indication for surgery, whether symptomatic or not. The conventional surgery is usually staged. Firstly there is a carotid-subclavian bypass or transposition on the right side and thereafter a transthoracic resection of the Kommerell's diverticulum and aortic angioplasty. The combined management with supraaortic revascularization followed with the stentgraft exclusion of the aneurysm is a sophisticated alternative. CONCLUSION: Experiences with the combined treatment published in the literature and ours are excellent, this technique is miniinvasive with a low complication rate. In our opinion it is the management of choice.

Reversal of propranolol blockade of adrenergic receptors and related toxicity with drugs that increase cyclic AMP.

An overdose of propranolol, a widely used nonselective beta-adrenergic receptor blocking agent, can result in hypotension and bradycardia leading to irreversible shock and death. In addition, the blockade of adrenergic receptors can lead to alterations in neurotransmitter receptors resulting in the interruption of the activity of other second messengers and the ultimate cellular responses. In the present experiment, three agents, aminophylline, amrinone, and forskolin were tested in an attempt to reverse the potential lethal effects of a propranolol overdose in dogs. Twenty-two anesthetized beagle dogs were given a 10-min infusion of propranolol at a dose of 1 mg/kg/min. Six of the dogs, treated only with intravenous saline, served as controls. Within 15-30 min all six control dogs exhibited profound hypotension and severe bradycardia that led to cardiogenic shock and death. Seven dogs were treated with intravenous aminophylline 20 mg/kg 5 min after the end of the propranolol infusion. Within 10-15 min heart rate and systemic arterial blood pressure returned to near control levels, and all seven dogs survived. Intravenous amrinone (2-3 mg/kg) given to five dogs, and forskolin (1-2 mg/kg) given to four dogs, also increased heart rate and systemic arterial blood pressure but the recovery of these parameters was appreciably slower than that seen with aminophylline. All of these animals also survived with no apparent adverse effects. Histopathologic evaluation of the hearts of the dogs treated with aminophylline showed less damage (vacuolization, inflammation, hemorrhage) than the hearts from animals given propranolol alone. Results of this study showed that these three drugs, all of which increase cyclic AMP, are capable of reversing the otherwise lethal effects of a propranolol overdose in dogs.

Polymer structure and solubility of deoxyhemoglobin S in the presence of high concentrations of volume-excluding 70-kDa dextran. Effects of non-s hemoglobins and inhibitors.

Earlier observations indicated that volume exclusion by admixed non-hemoglobin macromolecules lowered the polymer solubility ("Csat") of deoxyhemoglobin (Hb) S, presumably by increasing its activity. In view of the potential usefulness of these observations for in vitro studies of sickling-related polymerization, we examined the ultrastructure, solubility behavior, and phase distributions of deoxygenated mixtures of Hb S with 70-kDa dextran, a relatively inert, low ionic strength space-filling macromolecule. Increasing admixture of dextran progressively lowered the Csat of deoxyHb S. With 12 g/dl dextran, a 5-fold decrease in apparent Csat ("dextran-Csat") was obtained together with acceptable sensitivity and proportionality with the standard Csat when assessing the effects of non-S Hb admixtures (A, C, and F) or polymerization inhibitors (alkylureas or phenylalanine). The volume fraction of dextran excluding Hb was 70-75% of total deoxyHb-dextran (12 g/dl) volumes. Electron microscopy showed polymer fibers and fiber-to-crystal transitions indistinguishable from those formed without dextran. Thus when Hb quantities are limited, as with genetically engineered recombinant Hbs or transgenic sickle mice, the dextran-Csat provides convenient and reliable screening of effects of Hb S modifications on polymerization under near-physiological conditions, avoiding problems of high ionic strength.

HbC compound heterozygotes [HbC/Hb Riyadh and HbC/Hb N-Baltimore] with opposing effects upon HbC crystallization.

Compound heterozygotes of variant haemoglobins (Hbs) with HbC, with or without novel phenotypic changes, have provided insight into the molecular basis of the interacting haemoglobins and information concerning the role of specific residues in the crystallization of oxy HbC. A high phosphate buffer system has proved useful for studying the effects of variant haemoglobins (naturally co-existing with HbC in the red cell) on the oxy HbC crystallization process and has led us to conclude that beta87 and beta73 are contact sites of the oxy HbC crystal. We now present investigations from two HbC compound heterozygotes which exhibit opposing effects upon HbC crystallization: HbC/Hb N-Baltimore (beta95 Lys-->Glu) and HbC/Hb Riyadh (beta120 Lys-->Asn). The latter inhibits the in vitro crystallization of HbC, explaining the lack of erythrocyte abnormalities (with the exception of microcytosis) in the doubly heterozygous infant. In contrast, Hb N-Baltimore accelerates the crystallization of HbC, contributing to multiple abnormalities in red cell morphology, albeit in the absence of morbidity. We conclude that (1) beta120 and beta95 are additional contact sites in the crystal, and (2) the HbC/Hb Riyadh haemoglobinopathy demonstrates that crystallization may not be required for the generation of the observed microcytosis and increased red cell density in HbC-containing red cells.

Reversal of acute theophylline toxicity by calcium channel blockers in dogs and rats.

Theophylline, widely used in the treatment of pulmonary diseases, has a narrow therapeutic index; the recommended plasma levels being 10-20 micrograms/ml in humans. The misuse or abuse of theophylline can cause life-threatening central nervous system and cardiovascular effects. Increased intracellular Ca2+ levels are thought to play an important role in theophylline toxicity and death. The objective of this study was to determine whether Ca2+ channel blockers, e.g. verapamil, nifedipine, or diltiazem, prevent sudden death caused by theophylline treatment in rats and dogs. Groups of Sprague-Dawley rats were treated with theophylline alone (150 mg/kg i.p.) or with theophylline pretreatment followed by administration of verapamil (0.25 to 0.5 mg/kg i.p.), nifedipine (0.25 to 1.0 mg/kg i.p.), or diltiazem (0.5 to 1.0 mg/kg i.p.), 2.5 to 15 min later. The rats were observed for toxic signs and survival over a period of 15 days. All three calcium channel blockers significantly reduced the theophylline-induced sudden death in rats. In a separate study, neither verapamil (0.5 mg/kg i.p.) nor nifedipine (1.0 mg/kg i.p.) prevented the theophylline-induced myocardial necrosis in the rat. In beagle dogs, verapamil (0.5 mg/kg i.v.) prevented theophylline (15 mg/kg/min i.v. for 10 min)-induced hypotension, arrhythmias, and sudden death. Our results support previously reported findings that calcium plays a major role in theophylline-induced toxicity and death.

Measurement of the hemoglobin concentration in deoxyhemoglobin S polymers and characterization of the polymer water compartment.

Biological polymers contain freely exchangeable water within intermolecular crevices with restricted access to large extrapolymer solutes. Our recent studies highlighted large osmotic effects of such polymer water compartments (PWCs), and their substantial physiological and pathophysiological relevance. The size and accessibility of the PWC are critical parameters determining the polymers' osmotic properties. We report here a new experimental approach to investigate these parameters in deoxyhemoglobin S polymers. The size of the PWC is inversely related to the deoxyhemoglobin S concentration in the polymer (CP). Only an approximation of CP (approximately 69 g/dl) was previously available. By analyzing the distributions of soluble hemoglobin and a large molecular weight (MW) marker (14C-dextran, MW approximately 70kDa) in the supernatant and pellet of centrifuged gels, we obtained a reproducible value of CP, 54.7 (+/- 0.7)g/dl. This indicates that 60% of the polymer is composed of a water compartment inaccessible to soluble Hb and other non-interactive macromolecules. The accessibility properties of this PWC to smaller molecules were explored with markers of different MW. Non-interactive markers with MW < 200 kDa diffused freely in the PWC, whereas those with 300 kDa < MW < 1000 kDa showed partial exclusion. Higher MW markers were generally excluded, except molecules with elongated (rather than spherical) shapes or possible interactivity with hemoglobin. These results predict that dense sickle cells would significantly dehydrate on deoxygenation, generating a PWC of up to 60% to 80% of the cell water. Soluble enzymes would concentrate in the residual cytosol. For osmotic equilibrium, most of the ions and low MW substrates would concentrate in the PWC. Oxygenation-deoxygenation would thus cause dynamic oscillations in cell hydration and between states of single and double cytoplasmic water phases, the latter with a substantially altered internal environment. The relevance of such oscillations to the membrane and metabolic abnormalities of dense sickle cells requires further investigation.

Enhancement of acute myocardial lesions by asthma drugs in rats.

Asthma morbidity and mortality have risen significantly in the last 10 years. The reasons for the increase are multifactorial. One proposed explanation is possible myocardial toxicity arising from the use of beta-agonists alone or in combination with methylxanthines. Previous studies have shown that beta-agonists given alone and beta-agonist/methylxanthine combinations given at higher than recommended clinical doses induced dose-related cardiotoxicity and sudden death in rats. The objective of the present study was to determine whether or not beta-agonists given alone and in combination with methylxanthines at recommended clinical doses also induce cardiotoxicity and sudden death in rats. The beta-agonists, isoproterenol hydrochloride (15 micrograms/kg), fenoterol hydrobromide (40 micrograms/kg), and terbutaline hemisulfate (0.4 mg/kg) were given in single sc doses separately and concurrently with the methylxanthines aminophylline hydrate (20 mg/kg) and caffeine (40 mg/kg), which were given up to a susceptible animal model, the heavy Sprague-Dawley rat. beta-agonist-induced myocardial toxicity (necrosis) was observed. The toxicity was enhanced by aminophylline resulting in the sudden death (most likely due to ventricular fibrillation) of some animals. A decrease in serum iron levels was observed in rats of all beta-agonist and/or methylxanthine-treated groups.

Effects of non-psychotropic drugs on conditioned behavior of cats.

Cats were trained to obtain food pellets under a cycle reward condition in 4-6 weeks. These conditioned-behavior cats were then used for testing a group of non-psychotropic drugs, and any modification of the feeding cycle (FC) was considered as a side effect of the drug on conditioned behavior. All drugs were given orally. Of the 16 non-psychotropic drugs studied, only indomethacin caused a loss and irregularity in the FC. Antihistamines, acetylsalicylic acid, phenoxybenzamine and amantadine reduced the number of FC by about 50%. Studies of conditioned behavior in the cat appear to be useful for both the investigation of drug interactions and the detection of side effects of drugs not ordinarily considered to have central nervous system effects.