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Biomedical subjects

S Mazzoni

Publications and source records attributed to S Mazzoni.

At least 19 recordsLinked to original sources

Transient oscillations in Soret-driven convection in a colloidal suspension.

We present measurements of the transient stage of Soret-driven convective instability. The sample is a diluted colloidal suspension of silica spheres in water with an unusually large negative Soret coefficient S(T). A large temperature gradient (heating from above) is rapidly applied over the sample, while a shadowgraph imaging technique provides images of the convective flow. From the processing of the variance of the intensity of the images we are able to recover the time evolution of the overall intensity of the convective flow. A typical evolution of such signal exhibits, after a latency time, a peak followed by some damped oscillations leading to a steady-state value. Both the onset time tau(p) (the temporal position of the first peak), and the oscillation period tau(osc) show a power law dependence as a function of the solutal Rayleigh number R(s). The exponents found are compared with predictions from existing models.

Journal Article↗

Prevalence and patterns of self-initiated nutritional supplementation in men at high risk of prostate cancer.

OBJECTIVE: To define the prevalence and patterns of self-initiated herbal and vitamin supplementation among men at high risk of developing prostate cancer, as there is increasing public awareness of prostate cancer screening, risk-factor assessment and prevention, leading to increasing interest in the use and systematic study of nutritional therapies for prostate cancer prevention. SUBJECTS AND METHODS: Since 1996 our institution has prospectively maintained a prostate cancer-risk registry through its Prostate Cancer Risk Assessment Program (PRAP). Eligibility includes African-American men, any man with at least one first-degree relative or two or more second-degree relatives with prostate cancer, or men who tested positively for the BRCA1 gene mutation. A 420-item self-administered questionnaire was completed and included the use of nutritional supplements and complementary therapies. We divided men into groups who used supplements to lessen their cancer risk and those who did not. The prevalence and patterns of use were evaluated and the two groups then compared for differences in demographic, socio-economic and risk-perception variables. RESULTS: In all, 345 high-risk men were enrolled in the PRAP over a 5-year period. Data on the use of dietary or herbal supplements were available on 333 men (97%), of whom over half (170) reported taking one or more supplements to prevent prostate cancer. Supplement use was divided into eight categories, including vitamins, minerals, extracts from fruits/seeds, organic compounds, flowers/bulbs, leaves/bark, roots, or animal products. Most commonly used for self-initiated chemoprevention were vitamins (95%), minerals (28%), and fruit/seed extracts (18%). More than a quarter of men (27%) took three or more agents. Men taking proactive preventative measures were statistically more likely to be Caucasian and aged > 60 years (P < 0.05). African-Americans were less likely to self-initiate preventative steps. Men taking supplements tended to return more often for follow-up and participate in PRAP longer, while those not taking supplements tended to earn less and report less self-perceived risk. CONCLUSIONS: A significant proportion of men at risk of developing prostate cancer initiate measures they perceive to reduce their risk. Although the chemopreventative efficacy of many of these supplements remains unsubstantiated, they are widely perceived by the public to reduce the risk of developing prostate cancer. These data provide an insight into patient perceptions and misconceptions of chemopreventative strategies, and may help to refine recruitment efforts in multi-institutional prostate cancer prevention trials.

Adult↗

Pituitary function in chronic heart failure in the elderly.

Heart failure is a complex syndrome characterized by the activation of hemodynamic, immunologic and neurohormonal systems, which have beneficial effects in the short run, but will ultimately lead to secondary end-organ damage with worsening of LV remodeling and subsequent cardiac decompensation. A very important role seems to be played by modifications of the pituitary hormone systems. Due to the neurohormonal activation there is an increase in the activity in the renin angiotensin system, in the adrenergic nervous system, and in the cytokine system. In heart failure there is a decrease in many anabolic hormones, such as a decrease of GH and IGF-I, of DHEA/DHEAS with normal or increased F, and a decrease of LH and sex steroids, resulting in an important catabolic drive, capable of contributing to the development of cardiac failure and to sarcopenia and/or cachexia, frequently observed in the advanced stages of the disease. However, these hormone alterations have been described in relatively young patients with chronic heart failure, since the mean age of all the subjects studied was of about 60 yr and none of the studies have specifically addressed this issue in the very old patients, who represent the largest portion of population affected by this pathological condition. The role of hormone replacement therapy needs to be verified in a population of elderly patients with heart failure.

Aged↗

"Separation" of the mother-child couple: pregnancy and maternity of drug-dependent women.

Children of drug addicts are at risk of neglect and scanty maternal care. The objective of the present study was to identify homogeneous subgroups within a sample of drug addicted women, according to the quality of the outcome of the mother-child relationship. A group of 13 opiate-addicted women, followed from the seventh month of pregnancy up until the child was 2 years of age, underwent psychometric evaluation and was subdivided into two distinct groups based on whether the child remained within the family nucleus or was entrusted to a foster family or institution. The psychometric instrument used, an adaptation of Osgood's semantic differential which investigates maternal representations, allowed us to identify items with a very high predictability for the outcome of the mother-child relationship.

Adult↗

Juvenile drug addiction: a typology of heroin addicts and their families.

In this article the authors propose: 1) a typology of drug addiction cases consisting of four main classes: A. traumatic drug addiction, B. drug addiction from actual neuroses, C. transitional drug addiction, and D. sociopathic drug addiction; 2) a clinical study (with 18 months of follow-up data) involving 131 heroin addicts mostly treated with structural or counterparadoxical family therapy in the same psychotherapy center and in the same year; and 3) some preliminary conclusions emerging from an examination of the four-class typology with respect to the effectiveness of family therapy interventions. If, for example, structural family therapy techniques seem more suitable in type-B cases (similar to cases described by Haley in his Leaving Home), the counterparadoxical techniques are likely to be more effective in type-C cases (similar to the anorectics described by Selvini-Palazzoli).

Adolescent↗

[The role of reduction of the heart rate in the favorable effect of the beta blockers on myocardial ischemia due to isoprenalin in patients with angina pectoris].

In the patient suffering from angina, the protective effect of oxprenolol in the isoprenaline test is demonstrated by the reduction of disappearance of ischemic-type electrocardiographic alterations and of angina and rhythm disturbances. In our study, these results were obtained in spite of neutralization of the negative chronotropic effect of the beta-blocker through the use of an endo-auricular pacemaker. This points indirectly to the role played by the contractile state of the myocard in catecholamine-induced modifications of the oxygen intake of cardiac muscle.

Adult↗

[Electrocardiographic diagnosis of coronary insufficiency by means of right atrial pacing].

In 285 patients who underwent selective coronary arteriography and atrial pacing for electrocardiographic diagnosis of suspected coronary failure, the sensitivity of this test was found to be rather poor: 43% positive results for atrial pacing compared to 50% for the submaximal exercise test, 75% for the maximal exercise test and 63% for the isoprenaline infusion test. In our experience atrial pacing is of diagnostic value only where uncertainty persists after a negative isoprenaline infusion test and an exercise test likewise negative but for some reason submaximal.

Coronary Disease↗

[Proceedings: Results of the surgical treatment of valvulopathies and ischemic heart disease in patients older than 65 years].

53 patients aged from 65 to 76 years underwent surgery for valvulopathies (23 patients), atherosclerotic heart disease (24 patients) or both diseases combined (6 patients). All these cases were in NYHA fonctional classes III and IV except for one patient in class II. Hospital mortality after surgical treatment of these cardiopathies was 3.8% (2 deaths). The late mortality of 19% (10 deaths), though high, was of non-cardiac origin in 7 of these patients. The clinical and hemodynamic findings in the two patients who died in the postoperative period were compared with those in the others. These two patients were more severely ill and had a greater degree of cardiomegaly than the average patient in the surviving group. The satisfactory clinical improvement in these elderly cardiac patients suggests that surgery can be recommended at least up to 75 years of age if there are no obvious contraindications. Life expectancy of 13-16 years for patients aged 65 and 8-9 years for patients aged 75 is a further reason for advocating surgical intervention.

Aged↗

[Proceedings: Evaluation of the hemodynamic condition during the recuperative phase after the diagnostic isoproterenol test in a patient with coronary disease].

Previous investigations concerning isoproterenol infusion (PI) in the diagnosis of myocardial ischemia have shown that ischemic ECG changes are only significant if they persist or appear after discontinuing PI. In an effort to explain the mechanisms of this delayed response, hemodynamic parameters were measured in 10 patients with angiographically proven coronary disease before, during and after PI. It was found that the principal determinants of myocardial oxygen consumption (TTI and contractility) remain significantly elevated in the recuperation phase, but that aortic pressure and systemic arterial resistance, which diminish during PI, return to pre-infusion levels immediately after halting PI. The combined effects favor the late appearance of ischemic changes in the ECG. The coronary vasodilatation with resultant increased oxygen delivery to the myocardium seen during PI may be sufficient to meet the increased myocardial oxygen demand during PI but disappears immediately if PI is discontinued.

Adult↗

Contractility of the hypertrophied human left ventricle in chronic pressure and volume overload.

Nine patients with normal left ventricles (C), 10 patients with pressure load (PL) due to predominant aortic stenosis, and 9 patients with predominant volume load (VL) due to aortic incompetence were studied by left ventricular high-fidelity pressure measurements and cineangiography. Peak measured velocity of the contractile elements (Vpm) used as index of contractility and left ventricular muscle mass (LMMI) were determined. The patients with PL and VL were matched with respect to LMMI. In PL LMMI was 241 +/- 41 and in VL 254 +/- 42 gm. per square meter. Both were sizably increased (P smaller than 0.001) as compared to LMMI in C (89 +/- 24 gm. per square meter). Vpm was 1.41 +/- 0.20 ML per second in C. In PL and VLVpm was reduced to 1.05 +/- 0.26 (P smaller than 0.01) and to 1.07 +/- 0.33 ML per second (P smaller than 0.02). Vpm in PL was not different from Vpm in VL. Heart rate showed no major difference in the three groups. It is concluded that in two groups of patients with predominant PL and VL matched with respect to LMMI left ventricular contractility was depressed to a similar extent regardless of the stimulus to hypertrophy.

Animals↗

[The isoproterenol test in the electrocardiographic diagnosis of coronary insufficiency. Experience in 100 cases of ischemic cardiopathy].

Intravenous infusion of 10 to 30 gamma/min. of Isuprel for 3 to 7 minutes is accurate in diagnosing coronary disease in at least 80% of cases in our series of 100 patients with segmental coronary artery stenoses of 50% or more, demonstrated by coronary angiography. By comparing these 100 patients with a control group of 30 healthy subjects we can state that the late "ST" segment changes (persisting or appearing 3 minutes after stopping the infusion) are typical of coronary insufficiency. In patients without previous infarction, coronary insufficiency is expressed by a horizontal "ST" depression of 1 mm or more. In patients with previous infarction we observed either an "ST" depression or an "ST" elevation. The "ST" elevation, never observed in the control group, seems to have a different significance depending on whether or not a previous myocardial infarction has occurred. If there was no previous necrosis, severe coronary artery disease seems to be suggested and is a bad prognostic sign. This is not so if the patient has previously presented a myocardial infarction.

Adult↗