Role of plasma elongation on turbulent transport in magnetically confined plasmas.

The theoretical study of plasma turbulence is of central importance to fusion research. Experimental evidence indicates that the confinement time results mainly from the turbulent transport of energy, the magnitude of which depends on the turbulent state resulting from nonlinear saturation mechanisms, in particular, the self-generation of coherent macroscopic structures and large scale flows. Plasma geometry has a strong impact on the structure and magnitude of these flows and also modifies the mode linear growth rates. Nonlinear global gyrokinetic simulations in realistic tokamak magnetohydrodynamic equilibria show how plasma shape can control the turbulent transport. Results are best described in terms of an effective temperature gradient. With increasing plasma elongation, the nonlinear critical effective gradient is not modified while the stiffness of transport is decreasing.

Helicobacter pylori seropositivity in patients with unstable angina.

AIM: The pathogenesis of ischemic heart diseases has been correlated, on epidemiological and pathogenetic grounds, with infections by viruses and bacteria, including Helicobacter pylori (H. pylori). THE AIM: of this study were to investigate the association of unstable angina (UA) with anti-H. pylori seropositivity in a case-control study and to search for the classic cardiovascular risk factors in both infected and uninfected patients. METHODS: We studied 32 consecutive patients (20 males, 12 females), mean age 65 years (range 42-89), with final diagnosis of UA. A total of 64 subjects (40 males, 24 females, mean age 65 years, range 42-89) admitted to the Emergency Care Unit, age and sex-matched, served as controls. The presence of hypertension, serum levels of cholesterol and glucose, plasma levels of fibrinogen, smoking habit and social class were investigated in all patients. Cases and controls were inhabitants of NorthWestern Italy, and had similar socioeconomic status as based on working place and on instruction level. H. pylori seroprevalence was assessed by the presence of antibodies (IgG) against H. pylori by means of a commercial enzyme immunosorbent assay. RESULTS: Antibodies to H. pylori were found in 26/32 (81%) of the patients and in 34/64 (53%) of the controls (p=0.007); the odds ratio was 3.82 (95% confidence interval 1.27 to 12.04). Classical cardiovascular risk factors, such as socio-economic status, did not differ among patients with and without antibodies to H. pylori. CONCLUSION: Patients with unstable angina had a significantly higher seroprevalence of anti-H. pylori than the control population. Classical risk factors for ischemic heart disease, such as the indicators of socio-economic status, were equally distributed among infected or uninfected patients with UA.

Infection by Helicobacter pylori and acute myocardial infarction. Do cytotoxic strains make a difference?

The classical risk factors for acute myocardial infarction (AMI) fail to explain all the epidemiological variations of the disease. Among the risk factors recently reported, several infectious agents appear to increase the risk of AMI. Helicobacter pylori (H. pylori) infection, a bacterium involved in duodenal and gastric ulcer, gastric cancer and MALT-lymphoma, seems to be strongly associated with AMI. More virulent (anti-CagA positive) strains of the bacterium are almost exclusively the causative agents of such diseases. To determine the prevalence of H. pylori infection and of virulent strains, a case-control study was conducted in a group of male patients with AMI. A group of patients consecutively admitted to the Emergency Care Unit served as controls. We studied 223 consecutive male patients, mean age 60.2 (range 40-79) years, admitted for AMI to the Coronary Care Units at Hospitals in two towns of Northern Italy, 223 age matched male patients (mean age 61.8, range 40-79 years) admitted to the Emergency Care Unit, served as control. H. pylori seroprevalence was assessed by presence of antibodies (IgG) against H. pylori and anti-CagA in circulation. Among the patients we investigated the presence of hypertension, levels of cholesterol and glucose in serum, fibrinogen in plasma and smoking habits. H. pylori infection was present in 189/223 (84.7%) of the patients and in 138/223 (61.8%) of the control population (p < 0.0001 OR 3.42 [IC 95% 2.12-5.54]). The anti-CagA antibodies were detected in 33.8% of infected patients with AMI (64/189) versus 26.8% in the control subjects (37/138) (p:0.17, OR 1.40 [IC 95% 0.84-2.33]). Classical risk factors for AMI did not differ among patients with and without H. pylori infection. Patients admitted to the Coronary Care Unit for acute myocardial infarction had a notably higher prevalence of anti-H. pylori not restricted to virulent strains, when compared to a population of patients referred to the Emergency Care Unit. The classical risk factors for coronary disease were present in the patients with AMI irrespective of H. pylori status.

Residual alkaline phosphatase activity in pasteurized milk heated at various temperatures--measurement with the fluorophos and Scharer rapid phosphatase tests.

Milk containing three levels of milkfat (skim [0.5%], lowfat [2.0%], and whole [3.25%]) were heat treated at five different temperatures (59, 61, 63, 65, and 67 degrees C) using a laboratory scale, batch pasteurization method. Heated milk samples were removed at 5-min intervals, immediately cooled, and then assayed using the quantitative fluorometric method and the qualitative Scharer rapid test. Mean alkaline phosphatase (ALP) activity values as measured with the Fluorophos method decreased in all milk preparations as the time of sampling and temperature of heating increased. Samples representing the three fat levels and heat treated at 63 degrees C for 30 min, the minimum time/temperature allowed by the 1995 pasteurized milk ordinance (PMO), had ALP activity values <100 mU/liter. All values were below the 350 mU/liter standard for fluid milk products established by the Food and Drug Administration and cited in the 1995 PMO. Evaluation of the milks for adequacy of pasteurization with the Scharer rapid method indicated that those same milks were adequately pasteurized.

[Percutaneous tricuspid valvuloplasty]. / Valvuloplastica tricuspidale percutanea.

The authors herein describe the case of a 44 year old woman, who 14 years ago underwent surgical intervention after a rheumatic disease. A double mitral-aortic valvular implantation and a tricuspid commissurotomy was carried out. The patient come under our observation for severe congestive heart failure, while both mechanical prostheses were working well. Furthermore, the Doppler echocardiography showed a severe tricuspid stenosis (mean gradient = 8.6 mm Hg) and a concurrent mild to moderate valvular regurgitation. Because of her poor clinical condition and due to the high surgical risk it was decided to perform a balloon valvuloplasty of the tricuspid stenosis. The procedure, using the percutaneous femoral approach, was carried out with a TRIAD-TWIN AT (diameter = 18 + 18 mm; length = 4 cm; Mansfield) catheter and an Amplatz guide wire was advanced up to the apex of the right ventricle. Both balloons were inflated simultaneously on three occasions to a maximum pressure of 3.5 atmospheres for 60". At the end of the procedure there was the complete disappearance of telediastolic gradient, the valvular regurgitation remained unchanged (when compared to the pre-valvuloplasty control) and the mean trans-tricuspid gradient reduced to 4 mm Hg. Immediately following the procedure there was a remarkable, rapid hemodynamic improvement of the patient and at three months her condition is constant. In conclusion tricuspid valvuloplasty even using the percutaneous femoral approach can be performed and considered a simple and effective treatment.

[Preclinical left ventricular diastolic dysfunction in insulin-dependent diabetes]. / Disfunzione diastolica ventricolare sinistra preclinica nel diabete insulino-dipendente.

BACKGROUND: Isolated alterations of the left ventricular diastolic function have been described in diabetic insulin-dependent patients (IDDM), even in the absence of old age, hypertension, ischemic heart disease, left ventricular hypertrophy. Such alterations have been associated with microangiopathy but it is not known whether it is reversible or if there is a relation with the way the therapy is given. METHODS: Fifty-five subjects have been studied, of which 15 were healthy, 30 recently diagnosed IDDM without microangiopathy and 10 IDDM with microangiopathy. All the patients were under 35 years old and did not present risk factors for coronary artery disease, hypertension or autonomic neuropathy. The maximal exercise stress test proved negative. The diastolic function was studied using the results of Doppler echocardiography of the mitral flow and of isovolumetric relaxation time, with continuous and discrete parameters. RESULTS: The velocity of wave A and E, the relationship between them and their integrals are significantly greater in diabetics with microangiopathy than in those without it and in healthy subjects. There are no significant differences between healthy and diabetic subjects without microangiopathy using continuous parameters. Using discrete parameters diastolic damage is absent in the healthy subjects and is present in 48% of diabetics without microangiopathy and in 90% of those with it. CONCLUSIONS: Slight preclinical diastolic dysfunction is present in young recently diagnosed IDDM without microangiopathy. More severe dysfunction is present when there is also microangiopathy.

Double-blind crossover study of fenquizone compared to chlorthalidone in essential hypertension.

The clinical efficacy and tolerability of fenquizone (10 mg), a thiazide-like diuretic, were studied in comparison with chlorthalidone (25 mg) in 20 hypertensive out-patients during a four-month treatment course. Both drugs were very active in reducing hypertension. Fenquizone proved to be more active on systolic blood pressure, while there were no differences between groups regarding diastolic blood pressure. Chlorthalidone induced a more significant loss of plasma K+ than fenquizone. Fenquizone showed also a significant decrease of symptoms (headache, dizziness) due to hypertension. No undesirable side effects were observed.

Long-term follow-up after a controlled randomized post-myocardial infarction rehabilitation programme: effects on morbidity and mortality.

Prognosis during 4.5 years of follow-up after myocardial infarction (MI) in 2 groups of patients 25 to 65 years of age was related to physical rehabilitation and usual risk factors. We randomized 167 patients to a rehabilitation (R) group and a control (C) group (84 and 83 patients respectively). At the end of the training period, the R group had a significantly higher work capacity, a higher double product reached during the stress test and lower triglycerides. During the 55 months of follow-up after the physical training or the equivalent spontaneous activity, we observed the prevalence of risk factors and of cardiac events such as angina, new MI, unstable angina, coronary bypass grafting and cardiac death. Survival rate was 92.6% in the R group and 93.7% in the C group. There was no relationship between serum cholesterol levels, tobacco smoking, and blood pressure and mortality and morbidity after the infarction. R patients were more symptom-free (44% against 30%), and had almost the same number of episodes of unstable angina and of cardiac death. 6.1% of the R group and 11.2% of the C group developed a new myocardial infarction. As in previous randomized studies we did not reach statistical significance for long-term benefit, perhaps because of the low sample size. However, our study confirmed a favorable tendency in terms of symptoms and the self confidence of the R patients.

The prognostic significance of clinical history, exercise testing and ambulatory electrocardiography in patients with uncomplicated myocardial infarction.

The prognostic value of early clinical history, exercise testing and ambulatory electrocardiography was assessed in 263 men (mean age 50 years) recovering from an uncomplicated myocardial infarction (MI). During a mean follow-up period of 31 months, 11 patients died of cardiac causes, 22 developed a non fatal recurrent MI, 16 unstable angina (UA) and 16 underwent coronary artery bypass surgery. The appearance at the exercise stress test of an ischemic S-T segment depression of 0.2 mV or greater (P less than 0.001) as well as the achievement of a work load of 360 Kg-m/m' or less (P less than 0.01) and of a rate-pressure product of 200 Units or less (P less than 0.01), were found to be predictive of the future development of UA, but neither of cardiac death nor of non fatal recurrent MI. The ischemic response was also seen to be predictive of cardiac death (P less than 0.05). S-T segment depression of 0.1 mV or greater, angina and ventricular ectopic activity during the stress test and clinical history were not of predictive value. Complex ventricular ectopic activity (multiform extrasystoles, couplets and ventricular tachycardia) recorded during 24 hour ambulatory electrocardiogram was seen to be predictive of death and non fatal MI. Whereas some parameters such as the ejection fraction and the extension of coronary artery disease are generally accepted as good predictors for cardiac events, others, such as those derived from exercise testing, history and ambulatory electrocardiography may change their predictive value from one survey to another. These discrepancies are due to differences in patient characteristics, in methodology and in medical management.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic intrapericardial bleeding from a left ventricular aneurysm.

A case of an aneurysm of the left ventricle associated with recurrent hemorrhagic pericardial effusion is described. A small conduit connecting the left ventricle to the pericardial cavity was identified by left ventriculography. The mechanisms which prevented sudden cardiac tamponade and death are discussed.

Acute effects of chewable nifedipine on hemodynamic responses to upright exercise in patients with prior myocardial infarction and effort angina.

To evaluate the hemodynamic effects of nifedipine on anginal patients during exercise in the upright position, a placebo (P) and 20 mg of nifedipine were administered in a double-blind random sequence to ten patients presenting with exertional angina and a healed myocardial infarction. All patients had previously undergone coronary angiography. The effects of nifedipine in the upright position at rest, at the anginal threshold, and at the maximal level of exercise were studied. Nifedipine decreased systemic vascular resistances in upright position and increased the cardiac index. It reduced the severity of angina and allowed a higher physical work capacity without anginal symptoms. The most important beneficial effect of nifedipine appears to be the reduction in afterload, but an improvement of left ventricular function cannot be ruled out.