K(ATP) channel gene expression is induced by urocortin and mediates its cardioprotective effect

BACKGROUND

Urocortin is a novel cardioprotective agent that can protect cardiac myocytes from the damaging effects of ischemia/reperfusion both in culture and in the intact heart and is effective when given at reperfusion.

METHODS AND RESULTS

We have analyzed global changes in gene expression in cardiac myocytes after urocortin treatment using gene chip technology. We report that urocortin specifically induces enhanced expression of the Kir 6.1 cardiac potassium channel subunit. On the basis of this finding, we showed that the cardioprotective effect of urocortin both in isolated cardiac cells and in the intact heart is specifically blocked by both generalized and mitochondrial-specific K(ATP) channel blockers, whereas the cardioprotective effect of cardiotrophin-1 is unaffected. Conversely, inhibiting the Kir 6.1 channel subunit greatly enhances cardiac cell death after ischemia.

CONCLUSIONS

This is, to our knowledge, the first report of the altered expression of a K(ATP) channel subunit induced by a cardioprotective agent and demonstrates that K(ATP) channel opening is essential for the effect of this novel cardioprotective agent.

Language and publication in "Cardiovascular Research" articles

BACKGROUND

The acceptance rate of non-mother English tongue authors is generally a lot lower than for native English tongue authors. Obviously the scientific quality of an article is the principal reason for publication. However, is editorial rejection purely on scientific grounds? English mother tongue writers publish more than non mother-tongue writers--so are editors discriminating linguistically? We therefore decided to survey language errors in manuscripts submitted for publication to Cardiovascular Research (CVR).

METHOD

We surveyed language errors in 120 medical articles which had been submitted for publication in 1999 and 2000. The language "error" categories were divided into three principal groups: grammatical, structural and lexical which were then further sub-divided into key areas. The articles were corrected without any knowledge of the author's nationality or the corrections made by other language researchers. After an initial correction, a sample of the papers were cross-checked to verify reliability.

RESULTS

The control groups of US and UK authors had an almost identical acceptance rate and overall "error" rate indicating that the language categories were objective categories also for the other nationalities. Although there was not a direct relationship between the acceptance rate and the amount of language errors, there was a clear indication that badly written articles correlated with a high rejection rate. The US/UK acceptance rate of 30.4% was higher than for all the other countries. The lowest acceptance rate of 9% (Italian) also had the highest error rate.

DISCUSSION

Many factors could influence the rejection of an article. However, we found clear indications that carelessly written articles could often have either a direct or subliminal influence on whether a paper was accepted or rejected. On equal scientific merit, a badly written article will have less chance of being accepted. This is even if the editor involved in rejecting a paper does not necessarily identify language problems as a motive for rejection. A more detailed look at the types and categories of language errors is needed. Furthermore we suggest the introduction of standardised guidelines in scientific writing.

Ultrastructural characteristics, biological activity and pharmacological relevance of synthetic malaria pigment (beta-haematin)

Malaria pigment (haemozoin, HZ) is the detoxification product of haemoglobin-derived haem of intraerythrocytic malaria parasites. At schizont rupture, haemozoin accumulates inside host phagocytic cells. The chemical structure and the spectroscopic characteristics of haemozoin are identical to those of beta-haematin (BH), a synthetic pigment obtained from Ferriprotoporphyrin IX (Fe (III) PPIX) in acidic conditions. The process of BH formation is the target of quinoline antimalarials. Here, we summarise the results of our studies on the ultrastructural characteristics, biological and pharmacological relevance of synthetic vs. native haemozoin. 1) By electron microscopy, native HZ and synthetic BH appear as dark brown crystals, morphologically indistinguishable and are internalised by phagocytes at the same extent. 2) Both HZ and BH modulate the production of cytokines (TNF and NO) and increase the susceptibility to lipid peroxidation of mouse or human phagocytes. The antioxidant status of the phagocytes regulates the susceptibility to BH/HZ-mediated effects. 3) The process of BH formation from Fe(III)PPIX, hence haem detoxification, can be inhibited by electrochemically-reduced, Fe(II)PPIX molecules. Maintaining iron in the reduced state can thus be considered a new pharmacological target. This was confirmed by the observation that thiol-reducing agents (NAC, cystein) were able to inhibit BH formation and were toxic to parasites in vitro.

Apoptosis of endothelial cells precedes myocyte cell apoptosis in ischemia/reperfusion injury

BACKGROUND

Apoptosis contributes to cell loss after ischemia/reperfusion injury in the heart. This study describes the time course and level of apoptosis in different cell types in the intact heart during ischemia/reperfusion injury.

METHODS AND RESULTS

Isolated Langendorff-perfused rat hearts were subjected to perfusion alone (control) or to 35 minutes of regional ischemia, either alone or followed by 5, 60, or 120 minutes of reperfusion. Sections were stained by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and propidium iodide and with anti-von Willebrand factor, anti-desmin, or anti-active caspase 3 antibodies; they were then visualized by confocal microscopy. Sections were also examined by electron microscopy. No TUNEL-positive cells were seen in control hearts or hearts exposed to ischemia alone. Early in reperfusion, TUNEL staining was colocalized with endothelial cells from small coronary vessels. Endothelial apoptosis peaked at 1 hour of reperfusion and, at this time, there was clear perivascular localization of apoptotic cardiac myocytes, whose number was inversely proportional to their distance from a positive vessel. After 2 hours of reperfusion, apoptotic cardiac myocytes assumed a more homogeneous distribution. Active caspase 3 labeling was seen independent of DNA fragmentation during ischemia alone, but it colocalized with TUNEL staining over the 3 time points of reperfusion. Immunocytochemical findings were confirmed by electron microscopy and Western blotting.

CONCLUSIONS

In the very early stages of reperfusion, apoptosis is first seen in the endothelial cells from small coronary vessels. The radial spread of apoptosis to surrounding cardiac myocytes suggests that reperfusion induces the release of soluble pro-apoptotic mediators from endothelial cells that promote myocyte apoptosis.

[Glossary of terms of management and quality]

The implementation of a quality management system (QMS) in the health-care world is nowadays mandatory. This is a specific request not only of local laws but also of the World Health Organization which recently said that "By the year 2000, there should be structures and processes in all member States to ensure a continuous improvement in the quality of health care". In addition, we are bombarded by demands from patients, physicians, employers and the administration. However a QMS is something new for the medical doctor. We think that the first step to divulge the culture of quality in our field is to have a good knowledge of the specific terminology used in the QMS. This glossary explains the meaning of more than 80 terms related to the QMS.

Relative lymphocyte count: a prognostic indicator of mortality in elderly patients with congestive heart failure

BACKGROUND

A reduction in the relative lymphocyte count is a marker of the stress response; however, its prognostic value remains undetermined. The objective of this study was to investigate the predictive value of the relative lymphocyte count for survival in elderly patients with congestive heart failure (CHF).

METHODS AND RESULTS

One thousand two hundred seventy-four consecutive patients above the age of 65 years hospitalized with heart disease were enrolled in the CHF Italian Study and followed up for 3 years. Of these, 413 patients were excluded because of factors that could affect the lymphocyte count. Of the remaining 861 patients, 423 (49%) met the criteria for the diagnosis of CHF (mean age 76 +/- 7 years, 51% men), of whom 162 patients (38%) had a relative lymphocyte count < or = 20%. The 3-year all-cause mortality in patients with CHF and a relative lymphocyte count < or = 20% was 64% compared with 40% in patients with a relative lymphocyte count > 20% (P < .0001). The age- and sex-adjusted hazard ratio for death in patients with CHF and low relative lymphocyte count was 1.76 (95% confidence interval 1.34-2.32, P = .0001). After adjustment for baseline differences and variables associated with or known to affect lymphocyte count, the hazard ratio remained significantly different from 1.0 (hazard ratio 1.73, 95% confidence interval 1.21-2.48, P = .0026).

CONCLUSION

A low relative lymphocyte count is an independent marker of poor prognosis in elderly patients with CHF. The relative lymphocyte count is a simple, accurate, widely available, and inexpensive marker that can help to identify elderly patients with CHF who are at increased risk for mortality. The pathophysiologic mechanism of this observation remains to be determined.

Ace-inhibition with quinapril modulates the nitric oxide pathway in normotensive rats

Angiotensin-converting enzyme (ACE) inhibitors exert some cardiovascular benefits by improving endothelial function. We evaluated the effects of chronic treatment with quinapril (Q) on the l -arginine/nitric oxide (NO) pathway in normotensive rats under baseline and inflammatory conditions. The role of bradykinin was also investigated. The animals received for 1 week either the ACE-inhibitor Q (1 and 10 mg/kg/day), the B(2)receptor antagonist HOE 140, Q+HOE 140, or no drug. At the end of chronic treatment, rats underwent either a 6-h placebo or an E. coli endotoxin challenge. The following measurements were made: (i) endothelial and inducible NO synthase (eNOS and iNOS) protein expression; (ii) eNOS/iNOS activity; (iii) serum levels of nitrite/nitrate and tumour necrosis factor (TNF)- alpha; (iv) NO in the expired air (eNO). Q increased baseline aortic eNOS protein expression (up to 99%, P<0.001) and activity (l -citrulline synthesis up to 94%, P<0.01; serum nitrite/nitrate up to 55%, P<0.05). HOE 140 partially reversed Q-induced upregulation of eNOS (P<0.05). Moreover, Q counteracted LPS effects, i.e. increased the impaired eNOS pathway and limited iNOS induction (up to 94 and 24%, respectively), and reduced the increased nitrite/nitrate and TNF- alpha serum levels as well as eNO (up to 25, 38 and 28%, respectively, P<0.01 for all comparisons). HOE 140 did not influence Q effects on iNOS during endotoxaemia. In conclusion, in (patho)physiological conditions in rats, Q up-regulated eNOS with a bradykinin-mediated mechanism, while downregulated iNOS with a possible TNF- alpha -mediated mechanism.

[Electronic medical records: medical and legal aspects, privacy, safety, and legal validity]

Medical records must collect all data concerning in-hospital management of patients: data have to be verified and easily retrievable. Clinicians are responsible for both format and content of medical records. Respect of patient's privacy must be made sure both during on-line management and long-term storage of records. Computerization can offer many advantages to clinicians, but needs some significant adjustments: training and motivation of operators, arrangement of clinical processes and of administrative rules to technological developments. Nevertheless, some important results can be afforded: standardization of procedures, distribution of univocal, verified and ubiquitous data to all concerned operators, protection against undesired retrieval, reliability of effective reports. Preliminary condition is a clinical local area network, widespread into the institution. Database implementation must follow well accepted methodology: flow chart design of data dictionary, standardization of data coding, input of verified data, effective reporting. Access to data must be controlled by sophisticated and sure password system. Back-up of data must be automatically available with adequate timing and methodology. Respect of rules on patient's privacy must be realized whenever possible. Complex clinical records should be made available, containing data, signals and images (both single frames and dynamic sequences), due to continuous technical progress of diagnostic tools. Medical records must be available for long periods of time: database engine and managing tools must be selected among well accepted and largely available producers; informatic assistance must be assured for management and evolution of systems over the years.

Revascularization of severe hibernating myocardium in the beating heart: early hemodynamic and metabolic features

BACKGROUND

We investigated the effects of coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB) in selected patients with severe hibernating myocardium.

METHODS

Twelve patients (EF = 25% +/- 0.7%) with reversible ventricular dysfunction (from 2.0 +/- 0.06 to 1.6 +/- 0.05 left ventricular score index by echodobutamine, p < 0.01) in the territory of the left anterior descending artery (LAD) have been studied. Revascularization was achieved by anastomosing the left internal mammary artery to the LAD. The ischemic time of LAD was 9.0 +/- 0.4 minutes.

RESULTS

Left ventricular function increased 6 hours and 48 hours after revascularization (left ventricular stroke work index from 32 +/- 1.8 to 42 +/- 1.5 and 40 +/- 0.6 gxm/m2, respectively: p = 0.0001). During the surgical procedure, the heart did not release lactate or creatine phosphokinase. There were no perioperative deaths or severe complications.

CONCLUSIONS

Early hemodynamic and metabolic features of CABG without CPB in patients with hibernating myocardium suggest that this procedure is safe and results in a significant improvement of cardiac function without affecting myocardial metabolism.

Standardization of the physicochemical parameters to assess in vitro the beta-hematin inhibitory activity of antimalarial drugs

Intraerythrocytic plasmodia form hemozoin as a detoxification product of hemoglobin-derived heme. An identical substance, beta-hematin (BH), can be obtained in vitro from hematin at acidic pH. Quinoline-antimalarials inhibit BH formation. Standardization of test conditions is essential for studying the interaction of compounds with this process and screening potential inhibitors. A spectrophotometric microassay of heme polymerization inhibitory activity (HPIA) (Basilico et al., Journal of Antimicrobial Chemotherapy 42, 55-60, 1998) previously reported was used to investigate the effect of pH and salt concentration on BH formation. The yield of BH formation decreased with pH. Moreover, under conditions used in the above HPIA assay (18 h, 37 degrees C, pH = 2.7), several salts including chloride and phosphate inhibited the process. Aminoquinoline drugs formulated as salts (chloroquine-phosphate, primaquine-diphosphate), but not chloroquine-base, also inhibited the reaction. Interference by salts was highest at low pH and decreased at higher pH (pH 4). Here, we describe different assay conditions that eliminate these problems (BHIA, beta-hematin inhibitory activity). By replacing hematin with hemin as the porphyrin and NaOH solution with DMSO as solvent, the formation of BH was independent of pH up to pH 5.1. No interference by salts was observed over the pH range 2.7-5.1. Dose-dependent inhibition of BH formation was obtained with chloroquine-base, chloroquine-phosphate, and chloroquine-sulfate at pH 5.1. Primaquine was not inhibitory. The final product, characterized by solubility in DMSO, consists of pure BH by FT-IR spectroscopy. The BHIA assay (hemin in DMSO, acetate buffer pH 5 +/- 0.1, 18 h at 37 degrees C) is designed to screen for those molecules forming pi-pi interactions with hematin and thus inhibiting beta-hematin formation.

[Nitrates and nitric oxide]

Nitrovasodilators are pro-drugs able to release nitric oxide. They have been used in clinical practice for about 100 years and they are still widely used in the treatment of several diseases such as angina pectoris, acute pulmonary edema, and hypertensive crises. This article discusses the pharmacological differences of nitrovasodilators, describes the biochemical pathway of nitric oxide formation, and suggests some criteria to achieve the best therapeutic results.

[The appropriateness of hospital admissions: reflections for a global approach]

In accordance with a recent definition, appropriateness of medical care is a diagnostic-therapeutic intervention with a correct use of resources and competency, and a procedure that satisfies the request of patients. This definition considers not only the risk/benefit relationship but also the interaction between costs and benefits. In this light, the concept of appropriateness needs a global approach. The identification of the Mission and Vision of the structure, the use of medical guidelines, the distribution of documents which inform patients on the procedures carried out in the hospital and the modalities of access to the structure, the implementation of procedures which define hospital admission and finally the random check of medical records could represent important steps to implement a quality system aimed at guaranteeing the appropriateness of hospital admissions in accordance with the international standards for total quality management ISO 9000.

[A resources-activities analysis in cardiology: a report on Piemonte experience. The Cardiology Network of the Piemonte Section of the Associazione Nazionale Medici Cardiologi Ospedalieri]

We are living in an era characterized by cost-containment. Thus, expenditure for the health system represents one of the most important items of the national balance. Nowadays, the optimal management of health organization is essential. In addition, patients expect hospitals to provide more and more effective and efficient cures. With respect to this need, in order to achieve high standard of health cure, the identification of work and the time that the medical departments dedicate to a specific therapeutic and/or diagnostic procedure represent a fundamental tool for the optimal management of patients. However, to provide reliable results, these data should be collected in the largest number of structures possible. For this purpose, 17 departments of cardiology have organized a network with the goal of creating the most important data base on this matter available in Italy. The evaluation of the data obtained (more than 8000 medical procedures) allows us to identify the resources normally used for curing patients admitted to cardiological departments. These provide an extensive view of the work load in the Public Health Services fundamental to implementing a health service in accordance with the criteria of Total Quality Management. The present paper illustrates the scope of this study and the methods used to create the data base. In addition, it discusses some cultural aspects related to the introduction of managerial criteria in the medical arena. The detailed results, regarding the items analyzed, will be presented in a special paper.

[Catecholamines and beta-blockers in heart failure: some physiopathological and pharmacological reflections]

Although in the past the use of beta-blockers was considered inadvisable in patients with chronic heart failure, recent evidence strongly recommends the use of these drugs for chronic heart failure due to their positive effects on mortality and hospitalization. This paper analyzes some of the possible mechanisms responsible for the positive action of beta-blockers in heart failure. In fact, the effects of reducing sympathetic activity by beta-blockers on the myocardium, skeletal muscle, inflammatory system, metabolism of free fatty acids and glucose, insulin resistance, serum electrolytes, renal function and oxygen free radical generation are illustrated and discussed.

Heart failure-related myopathy. Clinical and pathophysiological insights

AIMS

To evaluate the relationship of skeletal and respiratory muscular dysfunction with the degree of clinical severity, cardiac impairment and exercise intolerance in patients with chronic heart failure.

METHODS AND RESULTS

Ninety-one patients (age 52.7+/-8 years) on standard therapy and in a stable clinical condition with normal nutritional status underwent evaluation of (1) clinical severity and metabolic status (NYHA class, weight, albuminaemia, natraemia, cortisol, insulin, neurohormones), (2) cardiac function (Echo, right heart catheterization), (3) exercise tolerance (peak VO(2)), (4) dynamic isokinetic forces of the quadriceps and hamstring (Cybex method), and respiratory muscle strength (maximal inspiratory and expiratory pressures). Fifty patients had a peak VO(2)<14 ml x kg(-1) x min(-1)(10.6+/-2) and 41 had values >/=14 (18.3+/-4). In the former group, leg and respiratory strength were significantly lower (extensors: 80+/-24 vs 100.9+/-22 Nm; flexors: 48.5+/-24 vs 75.3+/-22, both P<0.001; maximal expiratory pressure: 85.5+/-30 vs 104.8+/-31, P<0.01). Muscular strength was not related to indices of clinical severity, metabolic status, neurohormones or to the degree of systolic/diastolic cardiac function, but it was related to weight and age. Multivariate analysis of the peak VO(2)with clinical, haemodynamic and peripheral indicators showed weight (beta= 0.32, P = 0.007), muscular strength (beta= 0.32, P = 0.01) and NYHA class (beta= 0.31, P = 0.001) as the only independent predictors. The joint adjusted R(2)value was 0.48 (P<0.001).

CONCLUSION

Muscular dysfunction is part of the syndrome of heart failure. Together with symptom perception, it predicts nearly half of the variation in exercise tolerance.

High-dose heparin impairs nitric oxide pathway and vasomotion in rats

BACKGROUND

Platelet-activating effects have been reported with high-dose heparin in acute thrombotic disorders. Recent studies have shown that increased platelet aggregation is due to reduced nitric oxide (NO) production in endothelial cells cultured in the presence of high-dose heparin. The aim of this study was to determine whether heparin can affect the NO pathway and the regulation of the vascular tone in vivo.

METHODS AND RESULTS

Anesthetized and mechanically ventilated Sprague-Dawley rats were treated with high-dose heparin. After 4 hours, the endothelial constitutive NO synthase (ecNOS) protein content in the aorta decreased (36% reduction, P<0.05), as detected by immunoblotting, and NO-dependent vascular reactivity was impaired. In fact, the increase in mean arterial blood pressure after inhibition of ecNOS with NG-nitro-L-arginine methyl ester (30 mg/kg) was smaller in heparin-treated animals than in controls (+26. 9+/-4.8 versus +48.3+/-9.1 mm Hg, P<0.05), and further infusion of the biological ecNOS substrate L-arginine (0.5 g/kg) was ineffective in reversing systemic vasoconstriction (-1% versus 28% vasodilatation, P<0.001).

CONCLUSIONS

High-dose heparin can significantly affect vascular reactivity in vivo by downregulation of ecNOS protein expression.

The blood perfused isolated heart: characterization of the model

We have characterized the aerobic blood-perfused isolated heart model evaluating the hemodynamics and metabolism of both the blood donor animal and the isolated organ. Anaesthesia of the blood donor with sodium pentobarbital (30 mg/kg) increases arterial concentration of non esterified fatty acids (NEFA) from 80 +/- 6 to 452 +/- 70 microM; p < 0.01. Injection of 1,000 U/kg heparin causes a second significant increase from 452 +/- 70 to 1012 +/- 104 microM; p < 0.01. Insertion of the perfusion circuit, without the isolated heart, causes a reduction in blood pressure of the blood donor and a significant increase in norepinephrine from 277 +/- 44 to 634 +/- 130 pg/ml; p < 0.05. Two hours of aerobic perfusion of the isolated heart inserted in the perfusion circuit, decreases arterial pressure of the blood donor with a concomitant increase of plasma norepinephrine from 475 +/- 150 to 841 +/- 159 pg/ml; p < 0.05. Developed pressure, oxygen consumption, glucose and NEFA uptake of the isolated heart remain constant during two hours of aerobic perfusion, NEFA being the preferred substrate. Tissue content of high energy phosphates at the end of the perfusion is high and similar to that observed "in vivo". Despite this, there is a release of lactate and CPK from the isolated heart. We conclude that: 1) the model allows accurate measurement of hemodynamics and metabolism of both the isolated heart and the blood donor animal; 2) the perfusion procedure modifies the substrates concentration of the blood donor animal which, in turn, results in the preferential NEFA utilization of the isolated heart. These changes do not affect the functional parameters of the perfused heart.

[Emergency myocardial revascularization of the beating heart after angioplasty failure]

Occlusion of the left anterior descending coronary artery during angioplasty has a high mortality rate despite emergent myocardial revascularization. We describe two cases of coronary artery bypass grafting on beating heart without extracorporeal circulation to perform emergency operations after failed angioplasty.

Detection of nitric oxide in exhaled air of different animal species using a clinical chemiluminescence analyser

The aim of the present study was to evaluate the nitric oxide (NO) concentrations present in end-expired gas (FENO) of different animal species under basal and stimulated conditions using a clinical chemiluminescence analyser, which has been developed for measurement of single exhalations in humans. Anaesthetised, tracheotomised and artificially ventilated guinea pigs, rats and rabbits were prepared for recording systemic blood pressure and FENO. Stable levels of FENO were detected in expired air over a 1-h observation period in the three animal species tested. Rabbits exhibited the highest concentrations and output (FENO 12.9+/-1.0 ppb, VNO 9.0+/-0.7 nl min-1), followed by guinea pigs (FENO 6.2+/-0.70 ppb, VNO 1.7+/-0.19 nl min-1) and rats (FENO 0.9+/-0.01 ppb, VNO 0.25+/-0.00 nl min-1). L-arginine (1 g kg-1 i.v.) evoked significant increments in VNO in guinea pigs and rabbits but was ineffective in rats. However, L-arginine showed a direct effect on blood pressure in all the animal species tested, causing a rapid fall in the mean arterial blood pressure (MABP; 38, 48 and 50% decrease in rabbits, guinea pigs and rats, respectively; P<0.05). An inhibitor of endogenous NO synthesis, NG-nitro-L-arginine methyl ester (L-NAME, 20 mg kg-1 i.v.), decreased both basal and L-arginine-induced VNO in guinea pigs and rabbits, but was ineffective in rats. L-NAME increased MABP in all the animal species tested (58% in guinea pigs, 43% in rats and 18% in rabbits; P<0.05). The results indicate that it is possible to detect NO in the exhaled air of different animal species using a clinical chemiluminescence analyser and that different species exhibit striking differences in the levels of basal and stimulated NO output.