The Chemistry behind Catechol-Based Adhesion.

The adhesion of some marine organisms to almost any kind of surface in wet conditions has aroused increasing interest in recent decades. Numerous fundamental studies have been performed to understand the scientific basis of this behaviour, with catechols having been found to play a key role. Several novel bio-inspired adhesives and coatings with value-added performances have been developed by taking advantage of the knowledge gained from these studies. To date there has been no detailed overview focusing exclusively on the complex mode of action of these materials. The aim of this Review is to present recent investigations that elucidate the origin of the strong and versatile adsorption capacities of the catechol moiety and the effects of extrinsic factors that play important roles in the overall adhesion process, such as pH value, solvent, and the presence of metal ions. The aim is to detail the chemistry behind the astonishing properties of natural and synthetic catechol-based adhesive materials.

Solvent-Tuned Supramolecular Assembly of Fluorescent Catechol/Pyrene Amphiphilic Molecules.

The synthesis and structuration of a novel low-molecular-weight amphiphilic catechol compound is reported. The combination of a hydrophilic tail containing a catechol unit and a pyrene-based hydrophobic head favors solvent-tuned supramolecular assembly. Formation of hollow nanocapsules/vesicles occurs in concentrated solutions of polar protic and nonprotic organic solvents, whereas a fibril-like aggregation process is favored in water, even at low concentrations. The emission properties of the pyrene moiety allow monitoring of the self-assembly process, which could be confirmed by optical and electronic microscopy. In organic solvents and at low concentrations, this compound remains in its nonassembled monomeric form. As the concentration increases, the aggregation containing preassociated pyrene moieties becomes more evident up to a critical micellar concentration, at which vesicle-like structures are formed. In contrast, nanosized twist beltlike fibers are observed in water, even at low concentrations, whereas microplate structures appear at high concentrations. The interactions between molecules in different solvents were studied by using molecular dynamics simulations, which have confirmed different solvent-driven supramolecular interactions.

Coordination polymer particles with ligand-centred pH-responses and spin transition.

A bis-catechol ligand connected through an imine bond is used to fabricate switchable coordination polymer particles with pH-tuned spin transition responses.

QT interval prolongation and risk of life-threatening arrhythmias during toxoplasmosis prophylaxis with spiramycin in neonates.

We recently reported two cases of QT interval prolongation and cardiac arrest in newborns receiving antibiotic therapy with spiramycin, a macrolide agent extensively used for toxoplasmosis prophylaxis. In this study we assessed the effects of this drug on ventricular repolarization and on the potential risk of lethal arrhythmias in eight newborn infants in whom toxoplasmosis prophylaxis after birth was necessary. Electrocardiograms (ECGs) and echocardiograms were recorded during spiramycin therapy (350,000 i.u./kg/ day) and after its withdrawal. In a control group of eight healthy newborns matched for age and sex, no differences were found between two ECGs analogously recorded. The QT interval corrected for heart rate (QTc) was longer during spiramycin therapy than after drug withdrawal (448 +/- 32 msec vs 412 +/- 10 msec, +9%, p = 0.021). QTc dispersion, expressed as the difference between the longest and the shortest value in 12 different leads (QTcmax-min), was also higher during spiramycin therapy (60 +/- 32 msec vs 34 +/- 8 msec, +76%, p = 0.021), mainly because of a major lengthening of the longest QTc (QTcmax). QTc and QTc dispersion were markedly increased in the two newborns who experienced cardiac arrest after beginning treatment compared with the six neonates who had no drug-induced symptoms. During therapy seven of eight newborns had a rare abnormality in the thickening of the left ventricular posterior wall similar to that observed in patients with congenital long QT syndrome. This abnormality disappeared after drug withdrawal. Thus antibiotic therapy with spiramycin in the neonatal period may induce QT interval prolongation and increase QT dispersion. When this effect on ventricular repolarization is more marked, it may favor the occurrence of torsades des pointes and lead to cardiac arrest.

Influence of residual ischaemia on heart rate variability after myocardial infarction.

Despite the growing evidence for the positive predictive value of depressed baroreflex sensitivity and/or reduced heart rate variability after myocardial infarction, the mechanisms involved in these autonomic alterations are not fully understood. Specifically, the possible influence of residual ischaemia has not been assessed. To address this problem we studied the spectral analysis of heart rate variability in 21 patients with a first myocardial infarction in whom the only clinical correlate was the presence of residual ischaemia, as documented by the positive response to both an exercise stress test and an echocardiographic stress test. Data from these patients were compared with those obtained in a group of postmyocardial infarction patients similar for several risk factors, age, site of myocardial infarction, but without residual ischaemia. Patients positive for residual ischaemia had lower power in the whole spectrum (1146 +/- 158 vs 1631 +/- 159 ms2, P = 0.032) as well as in the low and high frequency bands of heart rate variability. A nocturnal increase in high frequency was observed in those without residual ischaemia (from 167 +/- 35 to 242 +/- 51 ms2, +45%, P = 0.034), but not in those with residual ischaemia (from 111 +/- 19 to 141 +/- 29 ms2, +27%, ns). Thus, residual ischaemia reduces heart rate variability after myocardial infarction. The autonomic effects of residual ischaemia probably contribute to its negative prognostic value after myocardial infarction.

Transfusion-transmitted human parvovirus B19 infection in a thalassemic patient.

BACKGROUND: Human parvovirus (HPV) B19 infection has been shown to be transmissible by clotting factor concentrates, most often resulting in asymptomatic seroconversion. So far, no case of B19 transmission due to single-donor transfusion has been documented. CASE REPORT: A case of transfusion-transmitted HPV B19 infection in a 22-year-old female thalassemia major patient is described. She presented with an aplastic crisis; this was followed 1 week later by transitory heart failure and acute tricuspid incompetence. The echocardiogram revealed a grade III tricuspid regurgitation and a floating vegetation on the atrial face of the tricuspid lateral leaflet. The tricuspid regurgitation and vegetation spontaneously disappeared within 15 days. Blood cultures for bacteria were repeatedly negative. IgM anti-HPV B19 seroconversion was documented in the acute phase. B19 DNA was detected by polymerase chain reaction and remained detectable up to 4 months after diagnosis. High-titer IgM anti-HPV and B19 DNA were also found in serum samples collected at the time of donation from one of the donors of the blood transfused before the onset of clinical symptoms. CONCLUSION: This case documents the transmission of HPV B19 by the transfusion of 1 red cell unit and the occurrence of possible transient cardiac involvement in this infectious complication.

Cardiologic abnormalities in patients with long-term lupus nephritis.

To assess the cardiological status of patients with long-term lupus nephritis we evaluated 30 patients (mean age 43 +/- 11 years) with lupus nephritis lasting from at least 10 years (mean 15 +/- 5 years). At the time of cardiological evaluation the mean plasma creatinine was 132.6 +/- 11.1 mumol/l and in 28 patients lupus had been quiescent for at least 3 years. Fourteen patients (46.6%) showed one or more cardiac abnormalities: 10 had valvular lesions (1 verrucous endocarditis, 9 thickening and stiffness of one or more valves)--4 patients had regional myocardial akinesis as a consequence of a previous cardiac infarct (one had valvular abnormalities too). One patient had pulmonary hypertension probably secondary to pulmonary vasculitis. No patient had pericarditis. These cardiac abnormalities proved to be statistically correlated with the number of ARA criteria (p = 0.045), the number of lupus flares (p = 0.004), the serum levels of cholesterol (p = 0.04) and of triglycerides (p = 0.025) as well as the duration of hypercholesterolemia (p = 0.005) and of hypertriglyceridemia (p = 0.007). In conclusion, in patients with long-term lupus nephritis cardiac lesions are frequent. The main lesions are non-verrucous valvulopathy (probably a consequence of healing verrucous endocarditis) and cardiac infarct (caused by an accelerated atherosclerosis). On the contrary cardiac lesions caused by active lupus as pericarditis, myocarditis and verrucous endocarditis are rare.

[Combination of transesophageal atrial pacing and echo-dipyridamole test in the diagnosis of coronary disease in patients with suspected angina pectoris and negative exercise test]. / Associazione dell'atrial pacing transesofageo al test eco dipiridamolo nella diagnosi di malattia coronarica in pazienti con sospetta angina pectoris e test da sforzo negativo.

BACKGROUND: Echo-dipyridamole test is an useful tool for non-invasive demonstration of inducible myocardial ischemia in patients with coronary artery disease, its sensitivity being consistently higher as compared with classic exercise stress testing. However, in patients with single vessel who often perform a normal or borderline stress test, even the sensibility of echo-dipyridamole test is comparatively reduced. METHODS: In 19 patients with clinically suspected angina (effort-related in 4, at rest in 8, mixed in 7) and normal exercise stress test, standard echo-dipyridamole test was performed. Thereafter, rapid atrial pacing, a procedure associated with a sharp increase of myocardial oxygen consumption, was performed by means of a transoesophageal catheter during the proceeding 5 min and during 4 min of repeated dipyridamole 0.56 mg/kg infusion. RESULTS: Standard echo-dipyridamole test induced ventricular wall motion abnormalities in 3 patients (one with borderline exercise stress test), whereas repeated pacing-sensitized procedure obtained wall motion abnormalities (apical, septal and lateral) in the same and in 4 additional patients. Coronary angiography demonstrated > 70% stenosis in 8/19 patients (single vessel disease in 5), 7 of whom had been correctly recognized by pacing-dipyridamole test; therefore, sensitivity of the latter as compared with standard dipyridamole test was 87% and 37% respectively. The anatomic correlation of induced wall motion abnormalities with coronary arterial stenosis was demonstrated in all cases. Specificity was 100% with both methods. CONCLUSIONS: Although limited by its restricted patient population, this study suggests that atrial pacing, performed via transoesophageal catheter, can significantly improve the positive predictive value of echo-dipyridamole test in coronary artery disease. By means of this simple procedure, the possibility of non invasively diagnosing even single vessel stenosis in patients with inconclusive exercise stress testing can be significantly improved.

Effect of calcium channel block on the wall motion abnormality of the idiopathic long QT syndrome.

BACKGROUND: We recently showed the frequent occurrence of an unusual ventricular wall motion abnormality, assessed by echocardiography, in patients with the idiopathic long QT syndrome (LQTS). Two new quantitative indexes were developed: Th1/2 (time needed to reach half of the maximal systolic thickening), which was smaller in LQTS patients than in controls; and TSTh (time spent at a very low thickening rate before rapid relaxation), which was much greater in LQTS patients, indicating the presence of a slow contraction in the late thickening phase. This marked late systolic "plateau," either rectilinear or with a peculiar double peak pattern, was significantly more frequent in patients with a history of syncope or cardiac arrest. The mechanism underlying this puzzling phenomenon remained unexplained. METHODS AND RESULTS: The present study assessed the effects of the calcium channel blocker verapamil on the contraction pattern in 10 LQTS patients (9 females and 1 male; mean age, 19 +/- 7 years) with a marked plateau pattern and in 6 healthy controls (4 females and 2 males; mean age, 28 +/- 5 years). Either verapamil (0.1 mg/kg) or saline was randomly injected over 2 minutes. Saline had no effect. In LQTS patients, verapamil increased Th1/2 by 27%, from 16.9 +/- 3.2% to 21.4 +/- 3.9% of the cardiac cycle (P = .005), and dramatically reduced TSTh by 92%, from 13.7 +/- 5.3% to 1.08 +/- 0.6% of the cardiac cycle (P < .00001). At the peak effect of verapamil, the contraction pattern of all patients was normal. In healthy control subjects, verapamil did not significantly change either Th1/2 (from 17.6 +/- 2.5% to 18.5 +/- 3.5% of the cardiac cycle) or TSTh (from 0.92 +/- 0.47% to 1.17 +/- 0.74%). CONCLUSIONS: This study demonstrates that the wall motion abnormality of LQTS is completely abolished by verapamil. These results suggest that symptomatic LQTS patients may have an abnormal increase in the intracellular calcium concentration before relaxation has completed, possibly linked to an early afterdepolarization, and that the contraction abnormality may be the mechanical equivalent of an early afterdepolarization.

Unsuspected echocardiographic abnormality in the long QT syndrome. Diagnostic, prognostic, and pathogenetic implications.

BACKGROUND: The idiopathic long QT syndrome (LQTS) is characterized by electrocardiographic abnormalities and by a high incidence of lethal arrhythmias. The present case/control study demonstrates the frequent occurrence of unusual and specific ventricular wall motion abnormalities in LQTS and their association with history of syncope or cardiac arrest. These anomalies were present in 23 of 42 LQTS patients (55%) and in two of 42 healthy controls (5%, p less than 0.0001) matched for age, sex, height, and weight. METHODS AND RESULTS: Two new measurements were developed to assess quantitatively the abnormalities observed. The first, Th1/2, is an index of the rapidity of the early contraction phase; the second, TSTh, is an index of the presence of a slow movement in the late thickening phase. Th1/2 was smaller in LQTS patients (15.0 +/- 4.1 versus 19.9 +/- 3.9% of the cardiac cycle, p less than 0.001), indicating that they reach half-maximal systolic contraction more rapidly than controls. TSTh was greater in LQTS patients (9.37 +/- 6.82 versus 2.88 +/- 4.46%, p less than 0.001), indicating that they spend more time at a very low thickening rate. A peculiar double peak pattern of late thickening was present in 11 patients and in no controls. These abnormalities were more frequent in symptomatic than in asymptomatic patients (20 of 26, 77%, versus three of 16, 19%, p less than 0.005; relative risk, 2.75). They were not affected by beta-blockade or by left cardiac sympathetic denervation. The same echocardiographic abnormalities were produced by right stellectomy in nine of nine anesthetized dogs, were not dependent on cycle length, and were not modified by subsequent left stellectomy. CONCLUSIONS: This study demonstrates a previously unsuspected abnormality in the ventricular contraction pattern of LQTS patients and, for the first time, provides evidence that a noninvasively detected cardiac abnormality is associated with a higher risk for syncope/cardiac arrest. The experimental reproduction of this echocardiographic abnormality by right stellectomy indicates that this newly found clinical characteristic of LQTS does not contradict the "sympathetic imbalance" hypothesis.

Cardiac alterations in 36 consecutive patients with idiopathic haemochromatosis: polygraphic and echocardiographic evaluation.

Thirty-six consecutive patients with idiopathic haemochromatosis (IH) were studied by electrocardiography (ECG), polygraphy, M-mode and 2-D echocardiography and Doppler-echocardiography. No significant correlations were found between ECG, PEP/LVET ratio and echocardiographic measurements. Left ventricular (LV) enlargement with impaired LV systolic function was present only in three patients (5.5%), of whom two died during iron-depleting therapy because of cardiovascular complications. Compared with controls, echocardiographic abnormalities were significantly more frequent and marked in subjects with higher iron overload than in those in whom it was lower. Ten patients were studied before and after iron depletion, nine of whom had only mild echocardiographic abnormalities at baseline examination. Significant reduction of end-diastolic thickness of the interventricular septum and LV mass (P less than 0.01 and less than 0.02 respectively) was observed. Also the end-diastolic thickness of the LV posterior wall and the end-systolic diameter of the left atrium reduced although not to a significant degree. The increased thickness of ventricular walls without impairment of LV systolic function is probably the first and still reversible cardiac alteration due to iron deposition in the myocardium. Later, with increasing iron overload, LV function becomes impaired and dilated cardiomyopathy develops. Early diagnosis and treatment of IH cardiopathy is needed before irreversible cardiac damage occurs.

Myocardial hydatid cyst ruptured into the pericardium: cross-sectional echocardiographic study and surgical treatment.

We describe a patient with a large intramyocardial hydatid cyst lying in the postero-lateral segment of the left ventricle near the atrioventricular groove level which ruptured into the pericardial sac, resulting in cardiac tamponade. Cross-sectional echocardiographic examination from a modified four-chamber apical view showed the multiloculated cyst and the breach connecting it to the pericardial sac, allowing for the definitive diagnosis and indication for emergency cardiac surgery. The risks of pericardiocentesis and invasive diagnostic procedures could thus be avoided.

Clinical and biochemical correlations in mitochondrial myopathies treated with coenzyme Q10.

We tested the efficacy of coenzyme Q10 (ubidecarenone, CoQ10) therapy in patients with Kearns-Sayre syndrome and other mitochondrial myopathies with chronic progressive external ophthalmoplegia (CPEO). We treated seven patients for 1 year with daily oral administration of 120 mg of CoQ10. Throughout the treatment most of our patients showed a progressive reduction of serum lactate and pyruvate levels following standard muscle exercise and generally improved neurologic functions. The ECG and echocardiogram showed no significant changes in our patients. None of our patients showed any improvement in ptosis and CPEO.

Hemodynamic evaluation by M-mode echocardiography in acute myocardial infarction.

We assessed the relationship between echocardiographic and hemodynamic parameters in 28 patients with documented acute myocardial infarction (AMI), who underwent M-mode echocardiography and Swan-Ganz catheterization during the same hospitalization. Patients with valvular heart disease were excluded from the study. On mitral valve echogram, DE interval was measured and the area enclosed by mitral valve echogram during DE interval (DE subarea ) was calculated in each echocardiogram. DE subarea /DE interval ratio was computed for each measurement set. Hemodynamic parameters were obtained in the usual fashion. Patients with pulmonary artery wedge pressure (PWP) less than 18 mm Hg showed a DE interval markedly longer than patients with PWP greater than 18 mm Hg: 81.72 +/- 15.23 vs 55.12 +/- 9.85 msec (p less than 0.001). Patients with cardiac index greater than 2.2 L min-1 m-2 had a DE subarea /DE interval ratio greater than patients with cardiac index less than 2.2 L min-1 m-2: 0.169 +/- 0.035 vs 0.094 +/- 0.017 dm2 sec-1 (p less than 0.001). Echocardiographic and hemodynamic data were then correlated in the whole study group, and it was found that DE interval was significantly (p less than 0.001) and inversely correlated to PWP; stroke index more than cardiac index was correlated (p less than 0.005) both to DE subarea /DE interval ratio and to DE interval itself; DE interval was not affected by heart rate. We were able to categorize the patients into four subsets on the basis of echocardiographic measurements. Our findings suggest the possibility of providing, through M-mode echocardiography, a noninvasive and accurate evaluation of PWP and stroke index.

[Echocardiographic recognition of Valsalva aneurysm. A case report (author's transl)]. / Riconoscimento ecocardiografico dell'aneurisma del seno di Valsalva. Descrizione di un caso.

M-mode echocardiography has proved in these last years to be a reliable method for the recognition and evaluation of several cardiac diseases, both congenital and acquired. The following is a case we have examined in which M-mode echocardiography has allowed us to diagnose a Valsalva sinus aneurysm combined with a bicuspid aortic valve causing a valvular steno-insufficiency. We discuss the genesis of an echogram situated in the left ventricular outflow tract. A very similar image had been ascribed in the past to the rupture of an aneurysm into the interventricular septum, which caused a filling of the septum itself in diastole and therefore the echogram described above. On the basis of two-dimensional echocardiography, angiography and the autoptic report we could exclude this hypothesis in our case. We suggest that the image might be due to a prolapse of the valvular leaflet in the left ventricular outflow tract and/or to the prolapse of the aneurysm itself in the tract between the valvular leaflet and the interventricular septum.

[The permanent electrostimulation with ventricular programmable pacemaker (author's transl)]. / L'elettrostimolazione definitiva con pacemaker ventricolare programmabile.

The purpose of this study is to evaluate the directions, reliability and long-term results of ventricular programmable pacemakers (PPM's). One hundred and ten PPM's, types Cordis and Medtronic, were implanted in 60 patients (pts) with intermittent or paroxysmal 2 degrees, 3 degrees a-v block and in 50 pts with S.S.S., mostly symptomatics, with a follow-up of 45 months. We did not observe either spontaneous or wrong reprogrammations nor circuit failure. In 92% of pts with Omni-Stanicor Cordis PM's, the stimulation was effective at the "lower" current amplitude, hence a longer life of the generator. Eighteen pts (16.3%) needed to raise ventricular rate (average 65 bpm): 6 pts for dizziness, syncopes or cardiac failure; 2 pts to control ventricular arrhythmias; 10 pts for a stable bradycardia lower than 50 bpm. In 11 pts with bradyarrhythmia due to S.S.S., cardiac output (CO) was measured both with thermodilution and echocardiography ("mitral valve echogram", being "r" of the two methods = 0.92), in spontaneous rhythm (63.3 +/- 3.13 bpm) and increasing artificially heart rate to 74.8 +/- 3.0 bpm; CO decreased from 4.65 +/- 0.13 l/min to 3.58 +/- 0.09 l/min, likely for the loss of atrial pumping. Similar results were obtained in other pts evaluated only with echocardiographic method after PM implantation: some of these underwent a further echocardiographic haemodynamic evaluation after 15 days of constant ventricular pacing at a mean rate of 75 bpm, with a different behaviour among them. This emphasizes the utility of PPM's in preserving spontaneous rhythm until bradycardia reaches dangerous levels and also the usefulness of echocardiography to evaluate, haemodinamically, the paced patient's ventricular performance.

[Echocardiographic evaluation of cardiac output in patients with acute myocardial infarction (author's transl)]. / Determinazione ecocardiografica della portata cardiaca nell'infarto miocardico acuto.

Echocardiography is a non invasive technique particularly useful to assess both hemodynamics and left ventricular performances; different methods have been proposed to evaluate echocardiographically the cardiac output. The aim of this work is to suggest a new method (planimetry of the area enclosed by echoes from the mitral valve) stating its advantages and limits and to test three already known methods (cubes method, method of Lalani and Lee, method of Rasmussen and coll.) comparing them to thermodilution. In 24 patients admitted in our Coronary Care Unit for acute myocardial infarction 30 measurements have been performed simultaneously with echocardiography and thermodilution. Statistical analysis (correlation coefficient with the method of the square minimums and Student's 't') of the results has shown that the cubes method is unprecise (P = NS) and unbiased (d = 0.97 +/- 15.46); Lalani-Lee method is unprecise (P = NS) and biased (d = 9.64 +/- 21.36) by a systematic underestimate error concealed by the poor precision; Rasmussen and coll. method is precise (P < 0.01) but biased (d = --3.03 +/- 5.5), the systematic mistake being entirely due to the group of patients with abnormal hemodynamics. Our method is precise (P < 0.01) and unbiased (d = --0.04 +/- 9.62) in patients both with normal and abnormal hemodynamics. Therefore this method offers the following advantages: 1) it is unbiased, even in the presence of abnormal left ventricular performance; 2) it is sufficiently precise, having a correlation coefficient with thermodilution of r = 0.80; 3) it measures directly the amount of flow due to the atrial systole; 4) the measurement is rapid and hardly biased by the reader.