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Biomedical subjects

R Ferrari

Publications and source records attributed to R Ferrari.

At least 397 records · Page 22Linked to original sources
PubMed1986

Myocardial recovery during post-ischaemic reperfusion: effects of nifedipine, calcium and magnesium.

We studied the effects of various interventions introduced at the time of post-ischaemic reperfusion on mechanical activity, tissue and mitochondrial calcium, mitochondrial function and tissue ATP and CP of isolated perfused rabbit hearts. These interventions were: nifedipine, low calcium (0.75 mM, 0.15 mM and 0.05 mM), high magnesium (15 mM) and high magnesium (15 mM) with low calcium (0.75 mM). Ischemia was induced by abolishing coronary flow for 60 min, followed by 30 min of reperfusion. The results indicate that nifedipine when given during reperfusion had no protective effect, whilst it was beneficial when administrated before ischaemia. Lowering calcium content of the perfusate during reperfusion may be advantageous, depending on the degree of calcium reduction. Reperfusion with high magnesium reduced the mitochondrial calcium overload and maintained the mitochondrial ATP-producing capacity but failed to modify the increase of tissue calcium and of diastolic pressure. Lowering calcium content in the presence of high magnesium resulted in better protection. These data suggest that the conditions of reperfusion may influence the capacity of myocardial recovery.

Adenosine Triphosphate↗
PubMed1986

Inhibitory effect of acute and chronic administration of digitalis on the sick sinus node.

We have determined the effects of the acute administration of intravenous (i.v.) digitalis administration (0.8 mg of digoxin in 5-10 min) on the electrophysiological variables of 12 normal subjects (group 1), 12 patients with asymptomatic sinus node bradycardia (group 2) and 34 patients with symptomatic sinus node dysfunction (SSS) (group 3). The injection of digitalis induced: an increase of sinus node cycle length (SNCL) in all groups; a 10% increase of sinus node recovery time (SNRT) in group 1, no changes in group 2 and a 25% increase in group 3; a tendency to increase, without reaching statistical significance, of corrected sinus node recovery time (CSNRT) and sino-atrial conduction time (SACT) in all groups. In 16 patients of group 3 the effects of oral chronic treatment with digoxin (0.25 mg daily for 7 days) was also determined. The results show that chronic treatment did not further affect SNCL, SNRT or CSNRT, but caused a greater increase of SACT than did the acute i.v. administration. Chronic treatment significantly reduced the sinus rate and increased the number of premature supraventricular and ventricular beats, measured by means of 24 hour-Holter monitoring. These data suggest that digitalis should be used with great caution in patients with SSS.

Administration, Oral↗
PubMed1986

Pulmonary haemodynamics of the yak, cattle, and cross breeds at high altitude.

The pulmonary arterial pressure of Ladakhi yaks, at an altitude of about 4500m, was not significantly different from that found in yaks bred at low altitude. The pulmonary arterial resistance, however, was slightly but significantly increased in the high altitude group. It is concluded that the yak has adapted genetically to high altitude by largely eliminating the hypoxic pulmonary vasoconstrictor response. The pulmonary arterial pressure and resistance were significantly higher in indigenous Himalayan cattle than in the yaks. The dzo (cow X yak) had pulmonary haemodynamics similar to those of the yak. Half of the stols (dzo X bull) had pulmonary haemodynamics similar to those of the yak, while in the other half the findings resembled those in the cow. The results suggest that the genetic attenuation of the hypoxic vasoconstrictor response is transmitted as a simple autosomal dominant.

Altitude↗
PubMed1986

Neocortical and olfactory bulb activity, in armadillos submitted to covering with soil.

Armadillos were submitted to an experimental condition in which their head and thorax were covered by a layer of soil 30 cm high. In this condition the electrical activity of the neocortex and of the olfactory bulbs was studied. Neocortical activity did not show signs of damage remaining without gross changes before, during and after the covering with soil. The olfactory bulbs showed a great decrease of bursting sinusoidal activity which almost instantaneously reversed when the soil was removed. The mechanisms of these changes are discussed.

Animals↗
PubMed1986

Foot-and-mouth disease vaccination: a multifactorial study of the influence of antigen dose and potentially competitive immunogens on the response of cattle of different ages.

Groups of 68 and 66 cattle aged 12 and 24 months respectively were each subdivided into 16 groups and inoculated with foot-and-mouth disease vaccines containing O1 Campos, A24 Cruzeiro and C3 Pando virus strains. The 140S antigen mass of the O1 and A24 valencies was varied while that of C3 was held constant. Multifactorial comparisons between the 21 day serum neutralising antibody titres showed that over most of the range there was a linear log dose response relationship. Doubling the antigen dose increased the serum antibody titres against both A24 Cruzeiro and O1 Campos by approximately 0.15 log10. The A24 antigen was about 30 times more immunogenic than the O1 with C3 intermediate between the two. At high antigen doses the responses flattened but the level at which this occurred depended on the immunogen administered. No difference could be demonstrated between the responses of 12- and 24-month-old cattle and there was no evidence of competitive inhibition or enhancement between the virus strains included in the vaccines.

Aging↗
PubMed1986

[Macro-CK type 1: a methodological study approach and its clinical significance].

Description of an analytical procedure in order to show the atypical-CK carriers that simulate an abnormal raising of CK-MB circulating levels in dosages for immune inhibition. This procedure was applied to two samples taken from patients of such a type, immune form neoplastic and cardiac pathology. A systematic dosage of a "real" MB isoenzyme is desirable in all the cases of very raised CK-MB activity.

Adult↗
PubMed1985

Changes in the cardiac glutathione status after ischemia and reperfusion.

In the isolated and perfused rabbit heart ischemia induced a rapid decline of contractility, associated with a reduction of the content of tissue GSH with no significant changes in GSSG. Reperfusion induced a small recovery of contractility, a substantial release of total glutathione and a further decrease in the content of tissue GSH with a significant increase of tissue GSSG. Glutathione reductase and glutathione peroxidase activities were not affected by ischemia and reperfusion. This study suggests a possible role for glutathione in the determination of functional damage induced by myocardial ischemia and reperfusion.

Animals↗
PubMed1985

Reproducibility of metabolical parameters during successive coronary sinus pacing in patients known to have coronary artery disease.

We have studied the reproducibility of myocardial extraction ratios of lactate, glucose and free fatty acids in patients with stable angina during atrial pacing. Two pacing periods, separated by an interval of 45 min, were imposed. The individual data were highly reproducible for lactate. Mean values for glucose and for free fatty acids were closely similar in the two successive tests, but the individual response was not so highly reproducible. We recommend the demonstration of the reproducibility of events during pacing in studies in which the effects of the therapeutic interventions are being assessed. This is especially so when observations are made in a small number of patients.

Angina Pectoris↗