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Biomedical subjects

E Fava

Publications and source records attributed to E Fava.

At least 37 records · Page 2Linked to original sources
PubMed1988

Monitoring of brain function by means of evoked potentials in cerebral aneurysm surgery.

Deliberate arterial hypotension is currently used to operate upon cerebral aneurysms. However, it is not ascertained whether this practice is really safe for all patients, especially those presenting with preoperative vasospasm. 50 patients, requiring surgical treatment for cerebral aneurysm, have been submitted, during surgery, to the recording of Somatosensory Evoked Potentials (SEPs) on median nerve stimulation. This technique allows the functional evaluation of neural pathways mediating the somatosensory stimuli and of primary somatosensory cortex; it is known that a decrease of cerebral perfusion may affect the SEP waveforms in terms of reduced subcortical conduction velocity (i.e., increased central conduction time, CCT) and of reduced cortical response amplitude. These changes may be apparent before a permanent neurological damage is produced. Preoperative SEP recording demonstrated a prolonged CCT, possibly related to vasospasm, in 9 patients, a normal clinical evaluation notwithstanding (grade I and II). During intraoperative deliberate hypotension, a SEP change has always been produced. No postoperative damage has been observed, however, as long as the CCT did not exceed 9 msec for 10 minutes (maximum normal CCT value is 6.7 msec) and as the cortical response had been visible throughout the whole surgical procedure. The critical value of CCT has been reached at a mean arterial pressure (MAP) lower than 60 Torr in patients with a normal preoperative SEP recording; at the opposite, in patients presenting with a prolonged preoperative CCT, the value of 9 msec was arrived at with a MAP value that is generally accepted as safe for all patients (75 Torr).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia↗
PubMed1984

Cat posture on a tilted platform.

The posture of cats trained to stand freely on a platform was studied during static tilts (up to +/- 30 degrees). Vertical projection of the center of mass on the support surface, as well as limb orientation in space and degree of limb flexion, varied minimally with platform tilt angle. The limbs' main axes were kept almost lined up with the vertical. This data indicates that postural control is simplified by strong internal constraints which limit the number of possible postural configurations. The mechanical advantages of this postural strategy are also considered. Finally, the data are discussed in the context of previously held views on the role of vestibular and neck reflex control of posture in intact animals.

Adaptation, Physiological↗
PubMed1984

A study of the relationship between muscle length, tension-time area and stiffness in cat areflexic soleus.

The relationship between muscle length and both tension-time area and stiffness were studied in the isolated cat soleus muscle during tetanic isometric contraction at different stimulus rates. The results show that: The area subtending the tension curve remains constant in a range of 8-10 mm of muscle length, for stimulation frequencies between 15 and 66 Hz. The muscle stiffness, measured using different amplitude stretches, remains constant over changes in muscle length of 10 mm. The stiffness is higher for smaller stretches than for larger ones. The data therefore show an approximately constant tension-time area and no significant changes in stiffness for variations in muscle length that exceed the physiological length variations during quiet standing. These results are discussed in the context of postural mechanisms.

Animals↗
PubMed1983

Properties of the spike afterhyperpolarization in pyramidal tract neurons.

Features of the spike afterhyperpolarization (AHP) recorded intracellularly have been analyzed in fast pyramidal tract neurons of cats. Cell input conductance increases during the AHP, possibly because of a change in potassium conductance, as suggested by an AHP equilibrium potential 10--15 mV negative to the resting membrane potential. When more spikes are evoked in succession, AHPs following the first one are strongly reduced in amplitude. The effect is virtually maximal (30--50% of the control) after a single spike and fades out by 200-400 ms after the last spike. At short interspike intervals the initial time course of the depression is hidden by summation occurring between consecutive AHPs.

Animals↗
PubMed1981

A horseradish peroxidase study of afferent projections to nucleus reticularis thalami in the cat.

Afferent projections from both the reticular formation and the thalamic relay nuclei to nucleus reticularis thalami (R) were studied using the HRP technique. Injections were performed in different regions of the nucleus. Numerous labelled cells were found ipsilaterally in i) the lateral geniculate nucleus (GL) following HRP injections in dorsolateral regions of R and in ii) the ventrobasal complex (VB) following HRP injections in the ventral regions. No labelling of brain stem reticular structures was ever found. These results provide evidence for a direct projections from the VB and GL nuclei to R. The functional meaning of these data is discussed in relation with previous anatomical and neurophysiological findings. The hypothesis of a significant role of R in feedback circuits modulating sensory information seems to be supported.

Afferent Pathways↗
PubMedDate not supplied

Neuronal generators of the visual evoked potentials: intracerebral recording in awake humans.

Flash and pattern reversal visual evoked potentials were recorded in awake patients undergoing stereotactic procedures for severe dyskinetic disorders resistant to medical treatment. The nucleus ventralis lateralis thalami was reached via an occipital approach. VEPs were recorded on the scalp at the entrance of the intracerebral electrode, and serially from sites at different depths. A polarity reversal of the surface recorded wave form took place as the intracerebral electrode was advanced beneath the surface cortical layers. As concerns F-VEPs, most of the scalp activity mirrored the potentials recorded down to the depth of 70-65 mm from the thalamus. The largest amplitude of intracerebral F-VEPs was obtained from recording sites at 50-70 mm from the thalamus, i.e., in the depth of the calcarine fissure. A negative wave, peaking around 47-50 msec, became evident in recording sites at 30-40 mm from the thalamus but vanished as the electrode was advanced farther. In only one patient could we record a small negative wave, peaking at 33 msec, in the vicinity of the corpus geniculatum externum. Furthermore, the oscillatory activity recorded from the scalp appeared to be generated in the cortical layers. PR-VEPs also underwent polarity reversal as the electrode traversed the cortex. PR-VEPs disappeared more superficially than F-VEPs. No PR-evoked activity could be recorded in the vicinity of the corpus geniculatum externum. We conclude that slow and fast components of VEPs recorded from the scalp are entirely generated in cortical layers.

Brain Mapping↗
PubMedDate not supplied

Role of SEP in identifying patients requiring temporary shunt during carotid endarterectomy.

EEGs and short-latency somatosensory evoked potentials (SEPs) to median nerve stimulation were recorded during 151 carotid endarterectomies, performed under general anaesthesia. Carotid occlusion did not affect either EEG or SEP in 120 cases (group A). In 31 cases the EEG showed "ischaemic" abnormalities (group B). A temporary shunt was inserted only in 16 B patients showing also severely depressed cortical SEPs within 2 min after carotid occlusion (group B shunt). In 15 B patients in whom SEPs were less affected, the operation was completed without shunt (group B no shunt). One intraoperative stroke occurred in group A and two in group B shunt. No neurological complications occurred in group B no shunt. Overall stroke rate was 2%. On retrospective analysis, latency and amplitude of N20 and P25 waves proved to be uninfluenced by carotid occlusion in group A, but were significantly affected in group B shunt. P25 amplitude alone was reduced in B no shunt. An arbitrary index (need-for-shunt index, NSI) was made in order to rate changes of P25 latency and amplitude. Its mean values were significantly different in the 3 groups. A threshold value is suggested above which shunt is required, as a useful adjunct to EEG, in order to balance prevention of brain ischaemia against the risks of shunt.

Aged↗
PubMedDate not supplied

[Psychotherapies in psychosocial centers in Lombardia: a point of view of psychiatrists and psychologists].

OBJECTIVE: The purpose of this study is the systematic analysis of operators' points of view about psychotherapies concretely performed in the Public Psychiatric Public Services and inside the global operating mode of the assistance. SETTING: The study has involved 26 CPS selected randomly in Lombardia. The sample has been built with 73 psychiatrists and 42 psychologists. MAIN OUTCOME MEASURES: All the therapeutists involved in this research have been submitted to a question-form querying socio-anagraphic data, professional training, orientations, operating modes in their CPS, rules and objectives of their psycotherapies, observations and evaluations about psychoterapic treatments and their effects. RESULTS AND CONCLUSIONS: Psychiatrists and psycologists working in CPS, mostly the younger ones (less than 45 years old), followed a personal training in over the 70% of the cases. The prevalent orientation is the psycoanalityc one in both the categories. The most part of therapeutists deems that there has been an evolution in their way of conceiving psychiatry inside the public service. The lines at these evolutions have been mentioned explicitly in the article. Psychiatrists and psycologists, even with some concrete differences; seems to have mostly homogeneous points of view: psychiatrists have a more flexible vision of which practices can be considered as a psychotherapy, whereas psycologists are more rigorously linked to theoric reference models and to rules learnt during their training. They are both slightly favourable to the use of psychotherapies in their services, even if, as a matter of fact, they are used by just a few patients. No contrast between psycotherapy and psycopharmacology has been detected from operators' answers. These practices seem to be both considered useful and integrable.

Adult↗
PubMedDate not supplied

[Protection and risk factors with respect to "burnout" of operatives. A comparative study of the psychosocial centers of Milan and Trieste].

The Maslach Burn Out Inventory (1981) has been applied to a group of workers at three Psychosocial Centres at Milan and Trieste characterised by differing work styles. Point scores were related to a number of variables relative to the professional situation and work organisation. The same scores were related to the results of a questionnaire (Contessa 1987) on the operator's perception of his activity and on motivational factors with respect to the professional choice in actuality and at the beginning of the career. It was therefore possible to identify a set of positive correlations that indicate the presence of factors which increase or reduce B.O. Level.

Burnout, Professional↗
PubMedDate not supplied

Evaluation of spinal cord function by means of lower limb somatosensory evoked potentials in reparative aortic surgery.

A group of patients undergoing aortic replacement of thoracic and abdominal aneurysms were studied by intraoperative recording of Somatosensory Evoked Potentials (SEPs). Lower limb nerves were stimulated and SEPs recorded at spinal and cortical level. Progressive changes of cortical SEPs until their disappearance were observed. In operations on the thoracic aorta, the spinal response was essentially unmodified, so that the observed alterations reflected true dysfunction of the spinal cord. The only patient who developed an intraoperative anterior spinal infarct had the longest period of absent SEPs and a striking latency prolongation when they returned. Postoperative recordings were absolutely normal. When the abdominal aorta was occluded, SEP alterations involved both cortical and spinal responses, so that it is difficult to distinguish between the relative roles of peripheral nerve and spinal cord ischemia. These findings indicate that SEPs can be reliably applied to spinal cord monitoring in the course of aortic surgery, even though they are mainly conducted in the posterior cord tracts.

Aged↗