Biomedical subjects

G Piccirillo

Publications and source records attributed to G Piccirillo.

43 records · Page 3Linked to original sources

PubMed1992

23Na-NMR study of cation cotransport in human red blood cells.

Na(+)-K+ cotransport in human erythrocytes from healthy subjects has been studied by means of 23Na-nuclear magnetic resonance (NMR) in the presence of the anionic paramagnetic shift reagent dysprosium (III) tripolyphosphate [Dy(PPP)2(7-)]. The intra- and extracellular 23Na-NMR signals were well separated, giving values of 6 +/- 1 mM for internal sodium concentration. Determination of the furosemide-sensitive Na+ efflux, in the presence of ouabain, was obtained by correlating the chemical shift variation of the external signal with changes in external Na+ concentration. For this purpose, calibration curves were generated. The values of the maximum efflux velocity (Vmax; 0.29-1 mmol.h-1.l cells-1) measured in 10 healthy adult male subjects were found to be within the range of values obtained by other authors. The NMR method proposed for the study of Na(+)-K+ cotransport is relatively simple and allows quick evaluation of cotransport Vmax values for a number of samples, being a good candidate for the study of this transport mechanism in the presence of different pathologies.

Biological Transport↗

PubMed1992

23Na NMR evaluation of human erythrocytes Na+/K+/CL-cotransport. A study in elderly hypertensives.

The behaviour of sodium transport systems across the cell membrane has been poorly investigated in elderly hypertension. Sodium efflux driven by Na+/K+/Cl-cotransport activity was therefore investigated (using a novel NMR-spectroscopy method) in 5 elderly hypertensive males (mean age 78 +/- 5 years) and 5 normotensive controls (mean age 79 +/- 3 years). In order to exclude any change in cotransport activity secondary to metabolic abnormalities, both patients and controls were non-obese and had normal glucose and lipid metabolisms. The Na+/K+/Cl-cotransport evaluation was performed after three months of pharmacological wash-out, under a diet containing 120 mEq of Na+/day. The resulting data showed that Na+ efflux due to outward Na+/K+/Cl-cotransport was higher in hypertensive group than in the normotensive one (0.50 +/- 0.10 mmol Na+/l cells/hr. vs 0.33 +/- 0.03 mmol Na+/l cells/hr., respectively, p < 0.05). Intracellular Na+ content was similar in both groups. At variance with previous data from the literature, our findings indicate that the Na+/K+/Cl-cotransport activity is elevated in elderly hypertensives.

Aged↗

PubMed1990

[Role of magnetic resonance spectroscopy in the diagnosis of ischemic cerebrovasculopathy].

NMR is still considered essentially, in the field of ischemic brain vascular disease, an imaging method. On the contrary, Authors review MR-spectroscopy possibilities, emphasizing that by this method it is possible to achieve a complete and dynamic study of brain energy metabolism, and therefore to identify markers of cellular injury clearly more sensitive and precocious than MRI morphological findings. Moreover, this method allows to easily evaluate cerebral blood flow, pharmacologic treatment efficacy, effects of eventual metabolic abnormalities on ischemia's evolution.

Animals↗

PubMed1990

[Transitory myocardial ischemia appearing after cranial trauma. Description of a case].

The authors describe a case of ECG alterations, indicating myocardial ischaemia, in a patient affected by mild cranial trauma. Both cycloergometric test and angiography of coronary vessels were normal. The authors conclude that every patient affected by brain injury should be monitored by the Cardiological Department, because of the high frequency of myocardial damage and lethal arrhythmias in these patients.

Coronary Disease↗

PubMed1988

Hypertensive emergencies in old age: effects of angiotensin converting enzyme inhibition.

Hypertensive emergencies, and to a certain extent their treatment, contribute to morbidity and mortality in elderly patients. We studied 22 hospitalized patients, aged 70-90 years, all of whom had moderate essential hypertensive. During acute hypertension, mean systolic and diastolic blood pressure rose to 230 +/- 24 and 120 +/- 22 mmHg, respectively. Symptoms of reduced tissue perfusion/oxygenation and/or organ failure occurred, forcing us to begin antihypertensive therapy. We administered 50 mg of the angiotensin converting enzyme (ACE) inhibitor captopril sublingually, and within 15 min, systolic blood pressure decreased by an average 60 +/- 16 mmHg and diastolic blood pressure by an average 25 +/- 14 mmHg. There was no significant change in the heart rate. In addition, we treated 22 comparable patients with 10 mg nifedipine sublingually and observed, in four cases, a greater fall in blood pressure (up to 90 mmHg) together with tachycardia. These results show the beneficial effects of captopril in the treatment of hypertensive emergencies in elderly patients. The absence of dangerous side effects indicates that ACE inhibitors can be used as first-choice drugs for the treatment of acute hypertensive crises, even in old age.

Administration, Sublingual↗

PubMedDate not supplied

Left ventricular mass and heart rate variability in middle-aged and elderly salt-sensitive hypertensive subjects.

Previous reports have shown that in salt-sensitive hypertension a high dietary salt intake can increase sympathetic activity. We evaluated the influence of the autonomic nervous system on myocardial hypertrophy by power spectral analysis of heart rate variability in middle-aged and elderly salt-sensitive hypertensive subjects. We compared autonomic nervous system activity in 32 salt-sensitive hypertensive patients (15 subjects with mean age, 42.4+/-2.4 years and 17 subjects with mean age, 74.6+/-1.6 years) and 20 age-matched normotensive controls. Power spectral analysis detects four spectral components: total power (TP), high-frequency (HF), low-frequency (LF) and very-low-frequency (VLF) power. In the elderly subjects we found an association between the left ventricular mass index (LVMI) and the following variables: very-low frequency (P<0.0001), 24-h urinary sodium excretion (P<0.0001) and diastolic blood pressure (DBP) (P<0.0001). In contrast, in middle-aged subjects we found a significant association between the LVMI and LF (P<0.001). In middle-aged, but not in elderly salt-sensitive hypertensive subjects, increased sympathetic activity correlated with the LVMI (P<0.0001). Our findings suggest an association between sympathetic hyperactivity and the LVMI in middle-aged subjects with salt-sensitive hypertension.

Journal Article↗

PubMedDate not supplied

Carvedilol in elderly patients with chronic heart failure, a 12 weeks randomized, placebo controlled open trial.

The encouraging results of recent multicenter clinical trials conducted in the US on the effect of carvedilol therapy in patients with chronic heart failure, prompted us to verify its tolerability in a group of elderly patients. For the open, randomized, placebo-controlled study, we selected 40 patients (28 men and 12 women, mean age 76.8+/-5.9 years) with mild, moderate or severe chronic heart failure. Exclusion criteria included dementia, chronic hepatitis, renal failure, severe vascular disease and respiratory failure. All patients were receiving treatment with digitalis, furosemide and ACE inhibitors. The study lasted 12 weeks. During the first week, all subjects received oral placebo or carvedilol, at a dose of 6.25 mg twice daily. The twice daily dose was then increased to 12.5 mg during weeks 2-4 and to 25 mg from weeks 5-12. At 0, after the 2 weeks of run-in, 4 and 12 weeks patients underwent assessment of systolic and diastolic blood pressure, heart rate, left ventricular ejection fraction, cognitive status and functional ability. Our findings indicate that elderly patients with congestive heart failure tolerate carvedilol therapy well. Carvedilol slightly improves heart function without altering functional or cognitive ability. A larger-scale trial in geriatric patients is now required to determine whether this treatment will reduce serious morbidity or mortality from heart failure.

Clinical Trial↗