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Biomedical subjects

A Federici

Publications and source records attributed to A Federici.

61 records · Page 4Linked to original sources
PubMedDate not supplied

Heart "timing" versus artery "timing". Neurovegetative effects in compensated and decompensated cardiocirculatory failure.

The hypothesis that the main local goal of the neurovegetative cardiovascular regulation is to set and maintain the cardiac cycle and the time constant of the arterial system within a given reciprocal proportion is discussed in this paper. Drastic changes in this reciprocal proportion can induce cardiocirculatory failure. Three different models of cardiocirculatory failure (congestive, hypovolemic and anaphylactic) have been considered in order to test the hypothesis. It is possible to outline a theory that is, decompensated failure occurs at very high levels of sympathoadrenal activation, when the arterial time constant increases when compared to the cardiac cycle, owing to mechanical properties of the arterial wall.

Animals↗
PubMedDate not supplied

The power transfer from the neuromuscular machinery to its load as a vegetative and somatic behaviour.

Models have been proposed in literature describing the contraction of visceral and somatic muscles as an interaction between the time-varying elastances of them and the loads they are working against. The aim of this paper is: 1) to make clear similarities between the models of visceral and somatic muscular contraction; 2) to stress the concept that the power transfer from a time-varying elastance to its load is a behaviour, i.e. an interaction between the entire neuromuscular machinery and the surrounding environment; 3) to propose a theory describing the various physiological and pathological behaviours of both visceral and somatic muscles as different ways of coupling between the time-varying muscular elastances and their loads. In this theory it is assumed that the entire neuromuscular machinery acts as a whole to set the most appropriate power transfer to achieve behavioural goals.

Elasticity↗
PubMedDate not supplied

Relation between the aortic pressure and the cardiac cycle in different neurovegetative conditions in the conscious dog.

The relation between mean aortic pressure (mAoP) and the duration of cardiac cycle (C) has been studied in resting conscious dogs in normal condition (n), after vagal blockade (vb), after sympathetic blockade (sb), and after combined blockade of the two systems (sb+vb). The relation has been found to be negative in all conditions. The different conditions are clearly differentiated by the slope of the relation between mAoP/C (= kPa/s = mW/ml) and C. The hypothesis is put forward that the balance between sympathetic and parasympathetic activities on the heart and the vessels produces the best compromise between the pump function of the heart and the afterload, in relation to the actual behavioural situation, in conscious animals.

Animals↗
PubMedDate not supplied

Intracranial bleeding in haemophilia. A study of eleven cases.

We have analysed eleven cases of intracranial haemorrhage occurring over the last 9 years in a population of 250 haemophiliacs. The purpose of this survey was to evaluate the prognostic possibilities available since the introduction of new diagnostic procedures and the progress in replacement therapy with anti-haemophilic factor. The sites of the haemorrhages and changes after treatment were visualized by CAT in 7 of the patients. Four patients died following dramatic evolution of their clinical conditions; two of them died before surgery, the others after having been operated on while in very deep coma. Two patients were successfully operated on for lesions occupying extracerebral spaces (one subdural and one extradural haematoma); replacement therapy avoided both recurrence and serious neurological defects. One patient with subarachnoid haemorrhage complicated by hydrocephalus was given an extrathecal shunt of cerebrospinal fluid. Four haemophiliacs had intracerebral haematomas: two of these needed surgery whilst the others recovered without serious neurological defects with replacement therapy only. These findings indicate that replacement therapy has considerably changed the prognosis of intracranial haemorrhage in haemophiliacs and that the CAT is a very helpful diagnostic procedure for evaluation of the acute stage and the follow-up.

Adolescent↗
PubMedDate not supplied

Considerations on seven cases of breakage of the polyethylene acetabular cup.

The authors describe seven cases of breakage of the polyethylene acetabular cup observed in 6 patients (5 females and 1 male) after a period of time ranging from 2 to 11 years postsurgery. By comparing the results obtained with those reported in the literature the authors analyze the possible etiopathogenesis of this rare late complication in total hip arthroplasty, which they particularly believe to be caused by hyperwear and fatigue phenomena of the acetabular cup, in turn caused by mechanical overloading.

Acetabulum↗