Changes in brain glucose metabolism in subthalamic nucleus deep brain stimulation for advanced Parkinson's disease

BACKGROUND

Despite its large clinical application, our understanding about the mechanisms of action of deep brain stimulation of the subthalamic nucleus is still limited. Aim of the present study was to explore cortical and subcortical metabolic modulations measured by Positron Emission Tomography associated with improved motor manifestations after deep brain stimulation in Parkinson disease, comparing the ON and OFF conditions.

PATIENTS AND METHODS

Investigations were performed in the stimulator off- and on-conditions in 14 parkinsonian patients and results were compared with a group of matched healthy controls. The results were also used to correlate metabolic changes with the clinical effectiveness of the procedure.

RESULTS

The comparisons using Statistical parametric mapping revealed a brain metabolic pattern typical of advanced Parkinson disease. The direct comparison in ON vs OFF condition showed mainly an increased metabolism in subthalamic regions, corresponding to the deep brain stimulation site. A positive correlation exists between neurostimulation clinical effectiveness and metabolic differences in ON and OFF state, including the primary sensorimotor, premotor and parietal cortices, anterior cingulate cortex.

CONCLUSION

Deep brain stimulation seems to operate modulating the neuronal network rather than merely exciting or inhibiting basal ganglia nuclei. Correlations with Parkinson Disease cardinal features suggest that the improvement of specific motor signs associated with deep brain stimulation might be explained by the functional modulation, not only in the target region, but also in surrounding and remote connecting areas, resulting in clinically beneficial effects.

Safety and efficacy of carvedilol in very elderly diabetic patients with heart failure

OBJECTIVE

Beta-blockers are often cautiously prescribed to older heart failure diabetics because of the paucity of published data and their perceived unfavourable effects on glucose metabolism, in spite of the evidence of their effectiveness and safety in middle-aged diabetic patients. The aim of this study was to compare the safety, tolerability and efficacy of long-term administration of carvedilol in a group of elderly patients with chronic heart failure, with and without concomitant diabetes.

METHODS

Two hundred and fifty-two patients aged > or =70 years with heart failure and left ventricular ejection fraction < or =40% were followed in specialised heart failure clinics. Diabetes was present in 29.7%. Carvedilol was associated with conventional optimised treatment in 64% of diabetics and 65% of non-diabetics (P = NS).

RESULTS

At baseline, diabetics presented with a longer duration of symptoms, higher Charlson comorbidity index, more frequent renal dysfunction and smaller left ventricular volumes than non-diabetics. New York Heart Association functional class and ejection fraction were similar in the two groups. At 1-year follow-up, tolerability (93.7 vs. 92.2%) and mean daily dose (24 +/- 17 vs. 23 +/- 14 mg/day) of carvedilol were similar in diabetics and non-diabetics. No worsening of fasting glucose, glycosylated haemoglobin and creatinine levels as well as the incidence of deaths and hospitalisations was observed in diabetics treated with carvedilol. Similar improvements in New York Heart Association class and mitral regurgitation severity were observed in diabetic and non-diabetic patients taking carvedilol. Ejection fraction showed a significant improvement, more pronounced in non-diabetics than in diabetics (+10 vs. +7 points; improvement of at least 10 points: 15 vs. 36%, P = 0.03).

CONCLUSIONS

Similarly to younger ones, also in older patients, diabetes does not negatively influence the safety, tolerability and efficacy of carvedilol. However, diabetes remains a strong prognostic factor limiting the reversibility of left ventricular systolic dysfunction and the effect of treatment on subsequent outcome.

The influence of endoscopic biliary stents on the accuracy of endoscopic ultrasound for pancreatic head cancer staging

BACKGROUND AND STUDY AIMS

Biliary stents have been found to interfere with endoscopic ultrasound (EUS) tumor (T) and nodal (N) staging in patients with periampullary cancer. Our aim was to determine whether this also occurs in patients with pancreatic head cancer.

PATIENTS AND METHODS

We studied a consecutive series of patients who were undergoing preoperative EUS for diagnosis and staging of suspected pancreatic cancer, some of whom had biliary stents in situ and some of whom did not. The main end point was the uni- and multivariate association of biliary stenting with T and N mis-staging by EUS. The surgical T and N stages were used as gold standards.

RESULTS

A total of 65 patients were identified (19 with biliary stents in situ and 46 without). Surgical stage T4 was found more frequently in patients with stents (53% vs. 22%, P = 0.014). The T stage by EUS was correct in 85% of the patients without biliary stents and in 47% of the patients with stents. The frequency of mis-staging by EUS was significant only among patients with a biliary stent. The distribution by EUS N stage did not differ significantly from the surgical N-stage distribution in the two groups of patients. According to the multivariate analysis, patients with stents were 6.55 times more likely to be incorrectly T staged (95% confidence interval [CI] 1.69-25.49) and 3.71 times more likely to be incorrectly N staged (95% CI 1.11-12.45) than patients without stents.

CONCLUSIONS

The results add support to the recommendation that EUS staging of pancreatic head neoplasms should be performed prior to stent placement.

Two-year outcome of a prospective, controlled study of a disease management programme for elderly patients with heart failure

OBJECTIVE

Elderly heart failure patients are at high risk of events. Available studies and systematic reviews suggest that elderly patients benefit from disease management programmes (DMPs). However, important questions remain open, including the optimal follow-up intensity and duration and whether such interventions are cost-effective during long-term follow-up and in different healthcare systems. The aim of this study was to determine the long-term efficacy of a hybrid DMP in consecutive older outpatients.

METHODS

Intervention consisted in combined hospital-based (cardiologists and nurse-coordinators from two heart failure clinics) and home-based (patient's general practitioner visits) care. The components of the DMP were the following: discharge planning, education, therapy optimisation, improved communication, early attention to signs and symptoms. Intensive follow-up was based on scheduled hospital visits (starting within 14 days of discharge), nurse's phone call and home general practitioner visits.

RESULTS

A group of 173 patients aged > or =70 years (mean age 77 +/- 6 years, 48% women) was randomly assigned to DMP (n = 86) or usual care (n = 87). At 2-year follow-up, a 36% reduction in all-cause death and heart failure hospital admissions was observed in DMP vs. usual care. All-cause and heart failure admissions as well as the length of hospital stay were also reduced. DMP patients reported, compared to baseline, significant improvements in functional status, quality of life and beta-blocker prescription rate. The intervention was cost-effective with a mean saving of euro 982.04 per patient enrolled.

CONCLUSIONS

A hybrid DMP for elderly heart failure patients improves outcomes and is cost-effective over a long-term follow-up.

Systo-diastolic ventricular function in patients with hypertension: an echocardiographic tissue doppler imaging evaluation study

BACKGROUND

Tissue Doppler imaging (TDI) has evolved to become a useful non invasive method that can complement other echocardiographic techniques in the assessment of left ventricular function in different clinical conditions. Spectral pulsed TDI can provide measurements of regional systolic and diastolic myocardial velocities and is particularly useful in detecting abnormalities of left ventricular systolic and diastolic function. We investigated the presence of systo-diastolic dysfunction in patients (pts) with hypertension compared with pts affected by hypertensive cardiomyopathy and normal control subjects.

METHODS

We evaluated 214 pts with traditional echocardiography and TDI: 69 normal control subjects (Group A); 145 pts with hypertension, divided according to base echocardiographic evaluation in 74 with no evidence of hypertensive cardiomyopathy (diastolic dysfunction and ventricular hypertrophy, Group B), and 71 with evidence of hypertensive cardiomyopathy (Group C). Pts groups were matched for age, sex, heart rate, smoking status and body surface area.

RESULTS

There were no significant differences in ventricular diameters, volumes, shortening and ejection fraction values; TDI showed a progressive systolic wave peak reduction from Group A to B and from Group B to C. Routinely Doppler diastolic function did not show any significant difference between Group A and B; TDI showed progressive E wave peak velocity decrease and A wave peak velocity increase from Group A to B and C and from Group B to C.

CONCLUSIONS

TDI evaluation showed a ventricular systolic dysfunction in pts with hypertensive cardiomyopathy; in addition, an early mild systo-diastolic dysfunction was detected in subjects with hypertension but no evidence of hypertensive cardiomyopathy.

Biphasic transoesophageal vs. transthoracic electrical cardioversion of persistent atrial fibrillation

OBJECTIVE

To compare the efficacy and safety of transoesophageal (TOC) vs. transthoracic (TTC) electrical cardioversion, both with biphasic shocks, for sinus rhythm (SR) restoration in patients with persistent atrial fibrillation (AF).

METHODS

We randomised 210 patients (151 male, 59 female, mean age 66 +/- 9 years) with persistent AF into two groups: group 1 (n = 104) undergoing TOC with a step-up protocol of 30, 50, 70 and 100 J, and group 2 (n = 106) undergoing TTC with a step-up protocol of 70, 100, 120 and 150 J.

RESULTS

The two groups were homogeneous as for clinical and instrumental characteristics, except for left ventricular ejection fraction (50.5 +/- 10% in group 1 vs. 53 +/- 8% in group 2, P < 0.05) and thoracic impedance (63 +/- 8 Omega in group 1 vs. 66 +/- 6 Omega in group 2, P < 0.005). SR was restored in 98 (94%) group 1 patients vs. 99 (93%) group 2 patients (P = NS). First shock was effective in 48 (46%) group 1 patients vs. 54 (51%) group 2 patients (P = NS). Mean delivered energy was 50.4 +/- 23.6 and 95.1 +/- 29.6 J; mean effective energy was 47.3 +/- 20.7 and 91.2 +/- 26.6 J in group 1 and group 2, respectively. Cross-over to the highest energy level was never effective. TOC tolerability was optimal (mean discomfort score 1.2 on a 1-4 grading scale). Markers of myocardial necrosis did not increase and no procedure-related complications occurred. On logistic regression analysis, the most predictive variables of unsuccessful cardioversion were AF duration (P = 0.0001) and low left atrial appendage emptying velocity (P = 0.02).

CONCLUSIONS

Both TOC and TTC with biphasic shocks are effective and safe for SR restoration in patients with persistent AF; however, the considerably lower levels of delivered and effective energies for SR restoration allow TOC to be performed during mild sedation with optimal tolerability, thus avoiding general anaesthesia.

Role of telecardiology in the assessment of angina in patients with recent acute coronary syndrome

We compared two models of assistance (telecardiology versus usual care) for patients discharged after acute coronary syndrome (ACS), in the assessment of angina. Two hundred patients were randomized into two groups at discharge for ACS: Group A to telecardiology and Group B to usual care. Early hospital readmission (in the first month) occurred in 16 patients (seven in Group A and nine in Group B). Six of Group A were readmitted for a cardiac cause (non-cardiac in one). Angina was the only cardiac cause. Five of the Group B patients were readmitted for a cardiac cause (non-cardiac in four). The results of the present study emphasize that patients with ACS suffer from a definite rate of cardiac symptoms within the first month (63%). Angina occurs more frequently within the first two weeks (68% of cases). Telecardiology slightly reduces hospital readmissions (telecardiology 44% versus usual care 56%), but better identifies true angina.

[Quality of care and management programs for the elderly with heart failure]

The majority of patients with heart failure are elderly. In order to point out the clinical characteristics and the quality of care of elderly heart failure patients we evaluated available data from national databases and observational studies. Elderly patients have more severe clinical manifestations, multiple etiologies and comorbid diseases, frequent hospital admissions, and a worse prognosis. As many as 30-50% of elderly patients with heart failure may have normal systolic function. In the elderly, evidence-based treatments are relatively underused with often inappropriately low doses. However, this "underuse" largely depends on the higher "frailty" of these patients (i.e. multiple coexisting diseases, disability, socio-environmental factors) and the lack of definite evidence on efficacy and safety of treatments in the very elderly. Several studies have documented the efficacy of specialized multidisciplinary heart failure disease management programs in terms of reducing hospital utilization, improving quality of life, functional capacity, patient satisfaction, compliance with diet and medications, and decreasing cost of care. Thus, there are opportunities to improve quality in many aspects of care, such as instrumental and multidimensional assessment and out-of-hospital management. Targeted clinical trials and rigorous observational studies with the aim at favoring the implementation of specific guidelines into clinical practice and continuity of care in the elderly are needed.

Efficacy and safety of ibutilide vs. transoesophageal atrial pacing for the termination of type I atrial flutter

AIMS

Comparing efficacy and safety of ibutilide vs. transoesophageal atrial pacing (ATP) for the termination of type I atrial flutter (AFL).

METHODS AND RESULTS

Eighty-seven patients affected by AFL lasting between 2 h and 30 days were randomized in two groups: Group 1-i.v. ibutilide treatment, up to 2 mg, and Group 2-ATP, with "burst" and "ramp" pacing protocols. Sinus rhythm was restored in 36/45 (80%) patients in Group 1 vs. 18/42 (43%) in Group 2 (P<0.0005). In Group 1, mean AFL duration was 11.4 +/- 7.7 days in responders vs. 12.1 +/- 7.6 in non-responders (P=ns), while in Group 2 it was 2.7 +/- 1.4 vs. 14.2 +/- 5.4 days (responders vs. non-responders, respectively, P<0.0001); 30/36 (83%) responders in Group 1 had AFL >48 h vs. 10/18 (56%) responders in Group 2 (P<0.05). Non-sustained polymorphic ventricular tachycardia occurred in 2 patients in Group 1 vs. none in Group 2 (P=ns). It did not require any specific treatment except the interruption of ibutilide infusion.

CONCLUSION

Both ibutilide and ATP proved to be safe and effective for recent onset type I AFL termination, but ibutilide was more effective when the arrhythmia had lasted longer than 48 h.

[Management programs for elderly patients with chronic heart failure]

PURPOSE

Most patients with heart failure are elderly with multiple coexisting diseases and heart failure is the most common discharge diagnosis in elderly hospitalized patients. Despite major advances in the pharmacotherapy of heart failure, hospitalization rates remain high, owing in large part to a multitude of psychosocial, behavioral, and financial factors that serve as barriers to effective compliance with prescribed treatment. In the last decade, several models have been proposed in order to optimise the long-term management of elderly patients with heart failure.

DESIGN

A review of most significant and recent models available was performed.

RESULTS

Several studies have documented the efficacy of specialized multidisciplinary heart failure disease management programs in terms of reducing hospital utilization, improving quality of life, functional capacity, patient satisfaction, compliance with diet and medications and decreasing cost of care.

CONCLUSIONS

At present, the greatest challenge in managing elderly heart failure patients is to more effectively implement proven treatments and disease management systems.

Safety and diagnostic accuracy of intravenous accelerated high-dose dipyridamole-atropine stress echocardiography

BACKGROUND

In the present study, the safety and diagnostic accuracy of a modified protocol with accelerated high-dose dipyridamole-atropine stress echocardiography, utilized in an attempt to significantly shorten the test imaging time with respect to the standard protocol, were evaluated.

METHODS

Three hundred and thirty-seven patients (231 men, 106 women, mean age 63 +/- 9 years) with known or suspected coronary artery disease underwent 404 tests. The ECG and blood pressure were continuously monitored during constant infusion of 0.21 mg/kg/min of dipyridamole over 4 min; atropine (0.50 mg at 5 and 6 min) was given in order to reach > or = 85% of the age-predicated heart rate. The wall motion score index and the 16-segment model were used to evaluate contractility. Eighty-nine patients underwent selective coronary angiography. Coronary artery stenosis was considered significant if the vessel diameter was < 50% of the normal value.

RESULTS

Eight-eight out of 404 tests were positive: 72 for echocardiographic criteria, 11 for ECG criteria, 2 for clinical symptoms, and 3 for combined criteria. Three hundred and sixteen tests were negative. In 303 tests atropine was administered and 380 tests were performed in pharmacological wash-out. The maximal heart rate was 105.8 +/- 9 b/min and the maximal blood pressure was 128 +/- 19/78 +/- 9 mmHg. No major side effects nor life-threatening complications were observed. In 24 tests (5.9%) only minor side effects occurred and in no case did these effects cause premature suspension of the test. The sensitivity, specificity and diagnostic accuracy of angiographically assessed coronary artery disease were 56, 86 and 73% respectively.

CONCLUSIONS

Accelerated high-dose dipyridamole echocardiography is practical, feasible and safe and allows for a significant reduction in the imaging time, with an increased cost-effectiveness and tolerance of the patients. In our experience the diagnostic accuracy of this new protocol was quite good and similar to that of the standard test.

Left ventricular mass and cardiovascular morbidity in essential hypertension: the MAVI study

OBJECTIVES

This study investigated the prognostic value of left ventricular (LV) mass at echocardiography in uncomplicated subjects with essential hypertension.

BACKGROUND

Only a few single-center studies support the prognostic value of LV mass in uncomplicated hypertension.

METHODS

The MAssa Ventricolare sinistra nell'Ipertensione study was a multicenter (45 centers) prospective study. The prespecified aim was to explore the prognostic value of LV mass in hypertension. Admission criteria included essential hypertension, no previous cardiovascular events, and age > or =50. There was central reading of echocardiographic tracings. Treatment was tailored to the single subject.

RESULTS

Overall, 1,033 subjects (396 men) were followed for 0 to 4 years (median, 3 years). Mean age at entry was 60 years, and systolic/diastolic blood pressure was 154/92 mm Hg. The rate of cardiovascular events (x100 patient-years) was 1.3 in the group with normal LV mass and 3.2 in the group (28.5% of total sample) with LV mass > or =125 g/body surface area (p = 0.005). After adjustment for age (p < 0.01), diabetes (p < 0.01), cigarette smoking (p < 0.01) and serum creatinine (p = 0.03), LV hypertrophy was associated with an increased risk of events (RR [relative risk] 2.08; 95% CI [confidence interval]: 1.22 to 3.57). For each 39 g/m(2) (1 SD) increase in LV mass there was an independent 40% rise in the risk of major cardiovascular events (95% CI: 14 to 72; p = 0.0013).

CONCLUSIONS

Our findings show a strong, continuous and independent relationship of LV mass to subsequent cardiovascular morbidity. This is the first study to extend such demonstration to a large nationwide multicenter sample of uncomplicated subjects with essential hypertension.

Expression of glyoxalase I and II in normal and breast cancer tissues

The present work aimed to study the activities of glyoxalase system enzymes, glyoxalase I (G I) and glyoxalase II (G II), as well as the expression of their genes in human breast carcinoma. Samples of tumoral tissue and normal counterparts were drawn from several patients during surgery. They served either for preparing extracts to be used in enzyme activity evaluations or for RNA extraction and subsequent northern blot analysis. A far higher activity level of G I and G II occurs in the tumor compared with pair-matched normal tissue, as shown by both spectrophotometrical assay and electrophoretic pattern. Such increased activities of G I and G II likely result from an enhanced enzyme synthesis as a consequence of increased expression of the respective genes in the tumoral tissue, as evidenced by northern blot. The present findings confirm a key-role of glyoxalase system to detoxify cytotoxic methylglyoxal and modulate S-D-lactoylglutathione levels in tumor cells. Moreover, they suggest a possible employment of GI inhibitors as anti-cancer drugs.

Soluble and membrane-bound acetylcholinesterases in Mytilus galloprovincialis (Pelecypoda: Filibranchia) from the northern Adriatic sea

Three forms of acetylcholinesterase (AChE) were detected in samples of the bivalve mollusc Mytilus galloprovincialis collected in sites of the Adriatic sea. Apart from the origin of the mussels, two spontaneously soluble (SS) AChE occur in the hemolymph and represent about 80% of total activity, perhaps hydrolyzing metabolism-borne choline esters. These hydrophilic enzymes (forms A and B) copurified by affinity chromatography (procainamide-Sepharose gel) and were separated by sucrose gradient centrifugation. They are, respectively, a globular tetramer (11.0-12.0 S) and a dimer (6.0-7.0 S) of catalytic subunits. The third form, also purified from tissue extracts by the same affinity matrix, proved to be an amphiphilic globular dimer (7.0 S) with a phosphatidylinositol tail giving cell membrane insertion, detergent (Triton X-100, Brij 96) interaction and self-aggregation. Such an AChE is likely functional in cholinergic synapses. All three AChE forms show a good substrate specificity and are inactive on butyrylthiocholine. Studies with inhibitors showed low inhibition by eserine and paraoxon, especially on SS forms, high sensitivity to 1,5-bis(4-allyldimethylammoniumphenyl)-pentan-3-one dibromide (BW284c51) and no inhibition with propoxur and diisopropylfluorophosphate (DFP). The ChE forms in M. galloprovincialis are possibly encoded by different genes. Some kinetic features of these enzymes suggest a genetic polymorphism.

[Heart arrest]

Cardiac arrest is one of the leading causes of mortality in industrialized countries and is mainly due to ischemic heart disease. According to ISTAT estimates, approximately 45,000 sudden deaths occur annually in Italy whereas according to the World Health Organization, its incidence is 1 per 1000 persons. The most common cause of cardiac arrest is ventricular fibrillation due to an acute ischemic episode. During acute ischemia the onset of a ventricular tachyarrhythmia is sudden, unpredictable and often irreversible and lethal. Each minute that passes, the probability that the patient survives decreases by 10%. For this reason, the first 10 min are considered to be priceless for an efficacious first aid. The possibility of survival depends on the presence of witnesses, on the heart rhythm and on the resolution of the arrhythmia. In the majority of cases, the latter is possible by means of electrical defibrillation followed by the reestablishment of systolic function. An increase in equipment alone does not suffice for efficacious handling of cardiac arrest occurring outside the hospital premises. Above all, an adequate intervention strategy is required. Ambulance personnel must be well trained and capable of intervening rapidly, possibly within the first 5 min. The key to success lies in the diffusion and proper use of defibrillators. The availability of new generation instruments, the external automatic defibrillators, encourages their widespread use. On the territory, these emergencies are the responsibility of the 118 organization based, according to the characteristics specific to each country, on the regulated coordination between the operative command, the crews and the first-aid means. Strategies for the handling of these emergencies within hospitals have been proposed by the Conference of Bethesda and tend to guarantee an efficacious resuscitation with a maximum latency of 2 min between cardiac arrest and the first electric shock. The diffusion of external automatic defibrillators is a preventive measure. Such equipment has permitted early defibrillation by non-medical first-aid personnel. These instruments contain software capable of recognizing an arrhythmia which may be defibrillated and of instructing the operator whether and when to press the defibrillation button. The latest instruments deliver the shock by means of a biphasic wave necessitating a lesser amount of energy which can be provided by lighter condensers. Thus such equipment weighs just a couple of kilograms. As suggested by ILCOR, for reasons of priority, such instruments should not only be available within hospitals and in ambulances but also on the territory, in particular in more crowded places. The availability of external automatic defibrillators in such places should reduce the time latency before intervention and thus increase survival. The ILCOR guidelines have suggested the constitution of an itinerary team well equipped for defibrillation and composed of trained personnel of State Institutions such as the Municipal Police, Traffic Police and the Fire Brigades. With regard to the majority of arrhythmias amenable to defibrillation which occur at home or in less crowded places, other strategies, such as primary prevention and training programs for categories at increased risk, must be employed. Antiarrhythmic drugs have long been considered the best solution for the prevention and treatment of ventricular tachyarrhythmias. However, the approach to these pathologies has drastically changed during the last few years owing to accumulating evidence in favor of defibrillators which may be implanted for the primary and secondary prevention of malignant ventricular arrhythmias. For patients with previous cardiac arrest, randomized studies have proven the advantages of such an approach compared to medical therapy. On the basis of the above, the guidelines for the use of antiarrhythmic implants have been modified. In most western countries, the laws regarding this aspect of medicine have recently been renewed. In the United States, where there is the "Law of the Good Samaritan", in order to protect and acquit persons who give first-aid, many states have adopted new laws which promote the use of external automatic defibrillators. Following recent dispositions by the President of the United States that defibrillators should be present in all Federal properties and on civil aircraft, a new Federal Law is about to pass. Italy lacks legislation regarding the use of defibrillators: in order to rectify this position, which is still anchored to existing dispositions of the civil and penal codes including those regarding the omission of first-aid, a bill entitled "The definition and modalities of the use of the external cardiac defibrillator" has recently been presented.

Molecular cloning and expression of a full-length cDNA encoding acetylcholinesterase in optic lobes of the squid Loligo opalescens: a new member of the cholinesterase family resistant to diisopropyl fluorophosphate

Acetylcholinesterase cDNA was cloned by screening a library from Loligo opalescens optic lobes; cDNA sequence analysis revealed an open reading frame coding for a protein of 610 amino acids that showed 20-41% amino acid identity with the acetylcholinesterases studied so far. The characteristic structure of cholinesterase (the choline binding site, the catalytic triad, and six cysteines that form three intrachain disulfide bonds) was conserved in the protein. The heterologous expression of acetylcholinesterase in COS cells gave a recovery of acetylcholinesterase activity 20-fold higher than in controls. The enzyme, partially purified by affinity chromatography, showed molecular and kinetic features indistinguishable from those of acetylcholinesterase expressed in vivo, which displays a high catalytic efficiency. Both enzymes are true acetylcholinesterase corresponding to phosphatidylinositol-anchored G2a dimers of class I, with a marked substrate specificity for acetylthiocholine. The deduced amino acid sequence may explain some particular kinetic characteristics of Loligo acetylcholinesterase, because the presence of a polar amino acid residue (S313) instead of a nonpolar one [F(288) in Torpedo] in the acyl pocket of the active site could justify the high substrate specificity of the enzyme, the absence of hydrolysis with butyrylthiocholine, and the poor inhibition by the organophosphate diisopropyl fluorophosphate.

Gallopamil activity on asynergic viable myocardium in acute myocardial infarction: insights on stunned and hibernating myocardium

The influence of the calcium antagonist gallopamil on the contractility of asynergic viable myocardium after acute myocardial infarction treated with thrombolysis was investigated by two-dimensional echocardiography. Sixteen patients with > or = 1 viable segment(s), identified during the low-dose phase (up to 10 micrograms/kg/min) of a dobutamine echocardiographic test (up to 40 micrograms/kg/min) performed 4-5 days after a first acute myocardial infarction, were given a gallopamil intravenous bolus (50 micrograms/kg) 12-24 hours later. Two-dimensional echocardiography was done before and 15 minutes after the bolus. A score index of 1 (normokinesis) to 4 (dyskinesis) and a 16-segment model were used. A segment was considered viable when a resting asynergy (score > or = 2) improvement of > or = 1 grade was seen during low-dose dobutamine. Follow-up echocardiograms were done 3-5 months later. A total of 30 viable segments were found; of these, 10 showed sustained improvement in contractility (group A) during high-dose dobutamine, while 20 exhibited a biphasic response returning to their basal contractile state (group B). After the gallopamil bolus, 9 of 10 group A segments improved their contractility, in comparison with 0 of 20 group B segments (P < .001). Infarct-related vessel significant (> or = 75%) coronary stenosis was present in the tributary vessel of 0 of 10 group A and of 20 of 20 group B segments (P < .001). At follow-up, 9 of 10 group A segments showed a spontaneous contractile improvement; of the 20 group B segments, 8 of 10 that underwent revascularization (7 angioplasty, 3 bypass graft) showed contractile improvement, in comparison with 0 of 10 segments not revascularized (P = .001). We conclude that gallopamil may reverse the contractile dysfunction of postischemic stunned myocardium in patients with acute myocardial infarction, whereas no effects are apparent on ischemic/hibernating myocardium.

Acetylcholinesterase at high catalytic efficiency and substrate specificity in the optic lobe of Eledone moschata (Cephalopoda: Octopoda): biochemical characterization and histochemical localization

In the optic lobe of the cephalopod mollusc Eledone moschata, two acetylcholinesterase forms I and II were detected, both showing a marked active site specificity with differently sized substrates. Catalytic efficiency (kcat/Km) of the prevailing form II is similar to that of acetylcholinesterases from vertebrate nervous system. Enzyme forms I and II were co-purified from a high-salt-Triton X-100 soluble extract of optic lobe by consecutive affinity chromatographies on procainamide- and concanavalin A-Sepharose columns and then separately obtained by preparative density gradient centrifugation. According to gel-filtration chromatography, sedimentation analysis and SDS-PAGE, the major form II is an amphiphilic globular dimer (135-136 kDa, 6.3-7.4 S) of monomers (66 kDa) S-S linked between terminal segments. Phosphatidylinositol anchors give cell membrane insertion, self-aggregation and detergent (Triton X-100, Brij 97) interaction. Form I, characterized only in part owing to its small amount, showed molecular size (129 kDa) and sedimentation coefficient (7.5 S) similar to those of form II; it is likely to be attached to the cell membrane by electrostatic interactions. Both forms behaved similarly with various inhibitors and underwent excess-substrate inhibition. The results obtained suggest a common origin of both form I and II from a single gene. The former could be a degradation product of the prevailing one (II), which is likely to be functional in cholinergic synapses.

[Management of ventricular arrhythmia in chronic congestive heart failure]

PURPOSE

To evaluate efficacy and indications of therapy for ventricular arrhythmias in patients with chronic congestive heart failure.

DESIGN

A review of most significant and recent clinical trials was performed.

RESULTS

In patients with severe left ventricular dysfunction, the desirable actions of antiarrhythmic drugs are attenuated and their negative inotropic and proarrhythmic actions are enhanced. Treatment should be limited to patients with malignant ventricular arrhythmias, or to patients considered at high risk. When indicated, amiodarone is usually well tolerated and safe. The prevention of sudden death in patients with heart failure should be based on optimized therapy of pump failure, reducing left ventricle work load and modulating neurohormonal systems with ACE-inhibitors and betablockers drugs. Further, an important role is held by anti-ischemic therapy, revascularization procedures, anticoagulant therapy and prevention of electrolytes unbalances. Patients with sustained of high risk arrhythmias, resuscitated from a cardiac arrest, should be considered for transvenous Implantable Cardioverter Defibrillator (ICD) implant.

CONCLUSIONS

Ventricular arrhythmias are common in heart failure patients, represent an important cause of sudden death and the choice of treatment is difficult because of the complexity of underlying mechanisms, frequency of adverse reactions and the severity of left ventricular dysfunction.

Expression of a single dimeric membrane-bound acetylcholinesterase in Parascaris equorum

A single form of cholinesterase was detected in the parasitic nematode Parascaris equorum and purified from a low-salt Triton X-100 extract of whole animals by affinity chromatography on an edrophonium-Sepharose matrix. Based on gel-filtration chromatography, sedimentation analysis and SDS-PAGE, such a cholinesterase is an amphiphilic globular (G2) dimer (125-129 kDa, 6.1 S). It includes some hydrophobic domain other than phosphatidylinositol, which gives autoaggregation, detergent interaction and also anchors the molecule to the cell membrane. The enzyme, probably functional in cholinergic neurotransmission, is an acetylcholinesterase showing a fairly low substrate specificity with thiocholine esters. Electrostatic interactions seem to play a major role in the catalytic activity. Studies with inhibitors gave complete inhibition with 1 mM eserine, low sensitivity for procainamide and for tetra(monoisopropyl)pyrophosphortetramide as well as higher inhibition with edrophonium chloride and 1,5-bis(4allyldimethylammoniumphenyl)-pentan-3-one dibromide. The enzyme also showed excess-substrate inhibition with acetylthiocholine. No cross-hybridization occurred between the gene(s) encoding acetylcholinesterase in P. equorum and ace-1 from the free-living nematode Caenorhabditis elegans. The expression of a single cholinesterase form in P. equorum, unusual in free-living nematodes, could be due to parasitic life adaptation with resulting reduction of locomotor activity.

Diagnostic and prognostic value of dipyridamole and dobutamine stress echocardiography in patients with Q-wave acute myocardial infarction

The aim of this study was to compare dipyridamole and dobutamine stress echocardiography, performed early in patients with acute myocardial infarction (AMI) to evaluate residual ischemia, viability, and prognosis. Fifty patients (mean age 55 +/- 9 years, 47 men, 3 women) with AMI, all treated with thrombolytic therapy, underwent standard dipyridamole and dobutamine tests, within the fifth day of the event. Wall motion score index and the 16 segments model were used to evaluate contractility. Forty-seven patients underwent coronary angiography within the tenth day of the event. The mean follow-up was 24 +/- 12 months. No side effects occurred during both tests. Both dipyridamole and dobutamine tests were positive for ischemia, in 32 and 33 of 47 patients, respectively (sensitivity 73% and 75%; specificity 67% and 67%); these tests induced an improvement of contractility in 23 and 38 of 139 abnormal segments at baseline, respectively (sensitivity 52% and 86%; specificity 100% and 100%). Cardiac events occurred in 26 of 50 patients, 22 with a positive dipyridamole test and 21 with positive dobutamine test. Thus, both tests were feasible, safe, and useful to evaluate residual ischemia, viability, and prognosis. No significant differences were found in sensitivity and specificity between tests.

Synthesis and study of thiocarbonate derivatives of choline as potential inhibitors of acetylcholinesterase

Fourteen alkyl and aryl thiocarbonate derivatives of choline were synthesized and studied as potential inhibitors of acetylcholinesterase (AChE). Twelve of the compounds inhibited AChEs derived from calf forebrain, human red blood cells, and octopus brain ranging from low to moderately high inhibition potency. The concentration of each inhibitory compound giving 50% inhibition of enzyme activity (IC50 values, which ranged from 1 x 10(-2) to 8 x 10(-7) M) was determined and is reported; inhibitor constants (Ki values) for the most inhibitory compounds, (1-pentylthiocarbonyl)choline chloride and (1-heptylthiocarbonyl)choline chloride, were calculated from kinetic data and are also reported. The inhibitors are competitive with substrate, and they are not hydrolyzed by the AChE activities. Certain of these new compounds may provide direction for the development of new drugs that have anticholinesterase activity and may be used for the treatment of Alzheimer's disease.

Acetylcholinesterase in Spirographis spallanzanii (Polychaeta: Sedentaria): presence of two dimeric membrane-bound forms

In the annelid polychaete Spirographis spallanzanii two acetylcholinesterases, named DS and HSDS, were detected. They differ in relative amount, membrane anchoring and pharmacological properties. Studies with inhibitors evidenced complete inhibition of both acetylcholinesterases by 10(-3) M eserine and different sensitivities for edrophonium or procainamide. Both enzymes, sensitive to BW284c51, were unaffected by iso-OMPA; at variance, only the HSDS form underwent excess-substrate inhibition. DS and HSDS enzymes were solubilized by homogenization in a low-salt or high-salt-Triton X-100 buffer and then purified by affinity chromatography on edrophonium- or procainamide-Sepharose column respectively. According to gel-filtration chromatography, sedimentation analysis and SDS-PAGE, the least represented (30%) DS form is a G2 amphiphilic globular dimer (124-130 kDa, 6.0-7.0S) with S-S linked monomers (66 kDa). Phosphatidylinositol anchors give cell membrane insertion, self-aggregation and detergent (Triton X-100, Brij 97) interaction. The prevailing (70%) HSDS acetylcholinesterase is once again a G2 form similar to DS enzyme in its molecular size (117-125 kDa), sedimentation coefficient (6.0S) of the native form and presence of S-S linked subunits (66 kDa). However, it is likely attached to the cell membrane by involvement of strong electrostatic interactions. DS acetylcholinesterase displays moderate active site specificity with differently sized substrates. The HSDS form is inactive on butyrylthiocholine. DS and HSDS forms show a comparable catalytic efficiency (kcat/K(m)) approaching that of other invertebrate enzymes. The results suggest that DS and HSDS enzymes, likely encoded by distinct genes, are both functional in cholinergic synapses.

Identification of viable myocardium early after acute myocardial infarction under beta-blockade by enoximone echocardiography

The influence of the beta-blocker metoprolol on the capacity either of low-dose dobutamine echocardiography or the recently introduced enoximone echocardiography to detect viable dysfunctioning myocardium after myocardial infarction was investigated. Initial clinical experience would suggest that the phosphodiesterase III inhibitor enoximona could be an alternative pharmacological stimulation, inducing an increase in contractility in the presence or absence of beta-receptor stimulation. Ten patients with a baseline low-dose dobutamine-echocardiographic test (up to 10 micrograms/kg/min) positive for myocardial viability in > or = 1 segment(s), performed 4-5 days after a first acute myocardial infarction treated with rtPA, were randomized after the administration of intravenous metoprolol (15 mg in three 5-mg boluses) either to dobutamine (up to 15 micrograms/kg/min) or to an enoximone intravenous bolus (1 mg/kg over 5 min) under echocardiographic monitoring, in a crossover sequence, with a 24-h interval. The infarct related artery was patent (TIMI grade 2 o 3) in all the patients. Follow-up echocardiograms were performed 5-7 weeks later. Resting asynergy was found in 40 segments; of these, 17 were viable. All the viable segments remained unresponsive during the post-metoprolol dobutamine infusion, while improved their contractility during enoximone echocardiography. Two patients suffering from early post-infarction angina underwent coronary angioplasty successfully. Eight out of ten patients (2 revascularized and 6 not) showed contractile recovery in a total of 14 segments at the follow-up echocardiogram. Sensitivity, specificity and overall accuracy in predicting reversible dysfunction after acute myocardial infarction for enoximone echocardiography were 93, 85, and 88%, respectively. Our results support the value of enoximone echocardiography in the identification of myocardial viability after myocardial infarction, in patients treated with beta-blockers, which interfere heavily with the results of dobutamine echocardiography.

Actinic lichen planus simulating melasma

A 23-year-old Italian woman presented with asymptomatic, symmetric, hyperpigmented patches on her face. The dermatosis became exacerbated in summer and closely resembled melasma. The histologic examination and immunofluorescence studies revealed typical features of lichen planus. Actinic lichen planus mimicking melasma is a rare dermatosis occurring mostly in women of oriental origin. The differential diagnosis of further facial melanoses will be discussed.

Acetylcholinesterase in Dendrobaena veneta (Oligochaeta: Opisthopora) is present with forms sensitive and insensitive to phosphatidylinositol phospholipase C. Biochemical characterization and histochemical localization in the nervous system

Three distinct acetylcholinesterases were detected in the annelid oligochaete Dendrobaena veneta. Two enzymes (alpha, beta), copurified from a Triton-X-100-soluble extract of whole animals by affinity (edrophonium-Sepharose) chromatography, were separately eluted from a Sephadex G-200 column. Gel-filtration chromatography, sedimentation analysis and SDS/PAGE showed the alpha and beta forms to be a globular dimer (110 kDa, 7.0 S) and a hydrophilic monomer (58 kDa, 5.0 S) respectively, both weakly linked to the cell membrane. The third form (gamma), also purified to homogeneity by slower filtration through an edrophonium-Sepharose matrix, proved to be an amphiphilic globular dimer (133 kDa, 7.0 S) with a phosphatidylinositol anchor giving cell membrane insertion, detergent (Triton X-100, Brij 96) interaction and self-aggregation. The alpha acetylcholinesterase showed a fairly low substrate specificity: the beta form hydrolyzed propionylthiocholine at the highest rate and was inactive on butyrylthiocholine; the gamma acetylcholinesterase, showing a marked active-site specificity with differently sized substrates, was likely functional in cholinergic synapses. Studies with inhibitors showed incomplete inhibition of all three acetylcholinesterase by 1 mM eserine and different sensitivity for edrophonium or procainamide. The alpha and beta forms, sensitive to 1,5-bis(4-allyldimethylammoniumphenyl)-pentan-3-one dibromide, were unaffected by tetra(monoisopropyl)-pyrophosphortetramide, while both these agents inhibited the gamma enzyme. All three forms showed excess-substrate inhibition by acetylthiocholine. Enzyme activity was histochemically localized in the nerve ring and its minor branches. Monomeric acetylcholinesterase (beta) is likely the only form present in the ganglionic glial framework.

Acetylcholinesterase in tentacles of Octopus vulgaris (Cephalopoda). Histochemical localization and characterization of a specific high salt-soluble and heparin-soluble fraction of globular forms

Transverse sections of Octopus tentacles were stained for acetylcholinesterase (AChE) activity. An intense staining, that was suppressed by preincubation in 10(-5) M eserine, was detected in a number of neuronal cells, nerve fibres and neuromuscular junctions of intrinsic muscles of the arm. Octopus acetylcholinesterase was found as two molecular forms: an amphiphilic dimeric form (G2) sensitive to phosphatidylinositol phospholipase C and a hydrophilic tetrameric (G4) form. Sequential solubilization revealed that a significant portion of both G2 and G4 forms was recovered only in a high salt-soluble fraction (1 M NaCl, no detergent), Heparin (2 mg/ml) was able to solubilize G2 and G4 forms with the same efficiency than 1 M NaCl. The solubilizing effect of heparin was concentration-dependent and was reduced by protamine (2 mg/ml). This suggests that heparin operates through the dissociation of ionic interactions existing in situ between globular forms of AChE and cellular or extracellular polyanionic components. Interaction of AChE molecular forms with heparin has been reported so far in only a few instances and its physiological meaning is uncertain. G2 and G4 forms, interacting or not with heparin, all belong to a single pharmacological class of AChE. This suggests the existence of a single AChE gene. Amphiphilic and hydrophilic subunits thus likely result either from the processing of a single AChE transcript by alternative splicing (as in vertebrate AChE) or from a post-translation modification of a single catalytic peptide.

N,S-bis-fluorenylmethoxycarbonylglutathione: a new, very potent inhibitor of mammalian glyoxalase II

A very potent competitive inhibitor of mammalian glyoxalase II activity, N,S-bis-fluorenylmethoxycarbonylglutathione (DiFMOC-G) has been synthesized and characterized. The Ki value for inhibition of glyoxalase II purified from calf liver is 0.08 microM. The Ki values for glyoxalase I inhibitions range from 285 to 500 fold higher than the values obtained for glyoxalase II inhibitions, depending on the source of the enzyme. Among other enzymes involved in glutathione metabolism, such as glutathione S-transferase, glutathione reductase, and glutathione peroxidase, only glutathione S-transferase is inhibited to a small extent by DiFMOC-G. Diesters of DiFMOC-G were prepared in order to improve transport of DiFMOC-G into mammalian tumor cells (rat adrenal pheochromocytoma, PC-12) in culture. Among the diesters synthesized, diisopropyl DiFMOC-G was found to be the most inhibitory to cell viability, with a [I]0.5 value of 3 microM.

Solubilization, molecular forms, purification and substrate specificity of two acetylcholinesterases in the medicinal leech (Hirudo medicinalis)

Two acetylcholinesterases (AChE) differing in substrate and inhibitor specificities have been characterized in the medical leech (Hirudo medicinalis). A 'spontaneously-soluble' portion of AChE activity (SS-AChE) was recovered from haemolymph and from tissues dilacerated in low-salt buffer. A second portion of AChE activity was obtained after extraction of tissues in low-salt buffer alone or containing 1% Triton X-100 [detergent-soluble (DS-) AChE). Both enzymes were purified to homogeneity by affinity chromatography on edrophonium- and concanavalin A-Sepharose columns. Denaturing SDS/PAGE under reducing conditions gave one band at 30 kDa for purified SS-AChE and 66 kDa for DS-AChE. Sephadex G-200 chromatography indicated a molecular mass of 66 kDa for native SS-AChE and of 130 kDa for DS-AChE. SS-AChE showed a single peak sedimenting at 5.0 S in sucrose gradients with or without Triton X-100, suggesting that it was a hydrophylic monomer (G1). DS-AChE sedimented as a single 6.1-6.5 S peak in the presence of Triton X-100 and aggregated in the absence of detergent. A treatment with phosphatidylinositol-specific phospholipase C suppressed aggregation and gave a 7 S peak. DS-AChE was thus an amphiphilic glycolipid-anchored dimer. Substrate specificities were studied using p-nitrophenyl esters (acetate, propionate and butyrate) and corresponding thiocholine esters as substrates. SS-AChE displayed only limited variations in Km values with charged and uncharged substrates, suggesting a reduced influence of electrostatic interactions in the enzyme substrate affinity. By contrast, DS-AChE displayed higher Km values with uncharged than with charged substrates. SS-AChE was more sensitive to eserine and di-isopropyl fluorophosphate (IC50 5 x 10(-8) and 10(-8) M respectively) than DS-AChE (5 x 10(-7) and 5 x 10(-5) M.

S-fluorenylmethoxycarbonyl glutathione and diesters: inhibition of mammalian glyoxalase II

Inhibitors having high specificity toward mammalian glyoxalase II, but not glyoxalase I, were sought as part of a program to study glyoxalase enzyme function in mammalian cells. The compound, S-fluorenylmethoxycarbonyl glutathione (FMOC-G), was synthesized and found to be a competitive inhibitor of purified calf liver glyoxalase II (Ki = 2.1 mumol/l). Inhibition constants (Ki values) for the other glyoxalase enzyme, glyoxalase I, and the glutathione-requiring enzyme, glutathione S-transferase, from other sources, were found to be 17 and 25 mumol/l, respectively. FMOC-G is a very poor inhibitor of glutathione reductase and glutathione peroxidase. Diesters (dimethyl, diethyl, diisopropyl) of FMCO-G were also synthesized, as proinhibitors, to improve transport of FMOC-G into mammalian tumor cells (rat adrenal pheochromocytoma, PC-12) in culture. The diesters were inhibitory to cell growth and variability; the most effective of these, diisopropyl FMOC-G, exhibited an [I]0.5 value of approximately 275 mumol/l. Diesters of FMOC-G may be useful in studies of the glyoxalase enzyme system in cultured mammalian cells.

Dipyridamole echocardiography evaluation of acute inferior myocardial infarction with concomitant anterior ST segment depression

The significance of anterior ST segment depression in inferior acute myocardial infarction (AMI) remains controversial. The aim of this study was to relate precordial ST segment depression to the topography of residual myocardial ischaemia, with myocardial mapping of the asynergic area and coronary anatomy. Twenty-five patients with first inferior AMI (15 patients with anterior ST segment depression: group A and 10 patients without anterior ST segment shift: group B), all underwent: (1) electrocardiographic evaluation on admission to the Coronary Care Unit and at 24 h intervals thereafter; (2) 2D-echocardiographic study within 3 h of CCU admission; (3) dipyridamole echocardiographic test (DET) (doses of dipyridamole up to 0.84 mg.kg-1 i.v. over 10 min) 4 days after AMI; (4) coronary arteriography within 14 days from AMI. To assess regional left ventricular wall motion, a 16 segment model was used and a wall motion score index (WMSI) was derived. The results of DET were correlated to the anatomy of the infarct-related vessel. Compared to group B, group A patients showed a significantly greater maximal ST segment elevation in inferior limb leads (lead III: 3.9 +/- 1.9 mm vs 2.2 +/- 1.1 mm, P < 0.05; aVF: 3.5 +/- 1.3 mm vs 1.7 +/- 0.8 mm, P < 0.001). Group A patients showed greater WMSI (1.35 +/- 0.22 vs 1.17 +/- 0.12, P < 0.05), with more frequent postero-lateral wall involvement (72% vs 20%, P < 0.05). No patient of either group showed asynergy of the anterior, anterolateral or anteroseptal segments. No differences in the distribution of coronary artery disease were observed.(ABSTRACT TRUNCATED AT 250 WORDS)