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Biomedical subjects

A Starita

Publications and source records attributed to A Starita.

13 recordsLinked to original sources
PubMed1995

NEUREX: a tutorial expert system for the diagnosis of neurogenic diseases of the lower limbs.

Specialist tutors have to transfer two types of knowledge to doctors who are specialising in a particular clinic: public declarative knowledge, including facts, notions, principles in that particular field; and their own private procedural knowledge acquired in years of direct experience. Embodying this knowledge into an expert system means that this information can be shared more rapidly, and tutoring is easier. This paper presents a tutorial expert system for neurological clinics which can emulate the diagnostic process of an expert neurologist for neurogenic diseases of the lower limbs, assist users in planning the optimal sequence of NG and EMG tests, interpret the results of these tests, and help users to achieve the most suitable diagnosis.

Diagnosis, Computer-Assisted↗
PubMed1994

Sex differences in surface EMG interference pattern power spectrum.

Sex differences in the spectral parameters of the surface electromyogram (EMG) power spectrum were studied during voluntary muscle contractions of different strength with rest in between. The influence of two different types of leads (unipolar and bipolar) on the values of the spectral parameters was also investigated under the same experimental conditions. The subjects were 15 healthy female and 15 healthy male volunteers. The relationship between the amplitude (root mean square) of the EMG and the force developed was not linear. The mean values of the median power frequency were lower in women than in men. With both types of lead, the increase in force was accompanied by a progressive increase in median power frequency in male and female subjects. The significant differences in spectral parameters observed in the two sexes are probably correlated with anatomic differences.

Adult↗
PubMed1992

Antigliadin antibody, D-xylose, and cellobiose/mannitol permeability tests as indicators of mucosal damage in children with coeliac disease.

A dual sugar (cellobiose/mannitol) permeability test using an iso-osmolar solution was performed, to compare its ability to predict small-bowel mucosal damage in children affected by coeliac disease with the determination of serum levels of D-xylose and antigliadin antibody. Eighty-three children (67 on gluten-containing diet and 16 on gluten-free diet) were investigated. The D-xylose and the serum antigliadin antibody test predicted accurately 70% and 78% of the small-bowel biopsy results, respectively, whereas the cellobiose-mannitol permeability test predicted 93%. These data confirm the superiority of the permeability test over the D-xylose test, although the former cannot be advocated as a substitute for jejunal biopsy. Our results suggest a complementary use of the permeability test and the antigliadin antibody measurement as screening tests for coeliac disease before applying more invasive procedures.

Adult↗
PubMed1988

Differences between surface EMG in male and female subjects evidenced by automatic analysis.

40 healthy volunteers (20 males and 20 females) have been studied by an automatic analysis of their surface EMG. The power density spectrum (PDS) of the electromyographic signal, derived from the tibialis anterior muscle, was used to evaluate the RMS values of the EMG developed during maximal voluntary (Vc) and evoked (Vm) contractions. The ratios between Vc, calculated over each of 5 frequency bands (5-15, 20-40, 45-70, 75-110, 115-160 Hz), and the total Vc have also been calculated. No significant differences emerge in the Vm values for males and females, whereas the Vc values for female subjects are found to be significantly reduced (P less than 0.001) with respect to the corresponding values for males. Significant differences have also been found concerning the percentage distribution of power in the above mentioned frequency bands for men and women (P less than 0.001). It can thus, be hypothesized that there are two different modalities of motor unit recruitment and that different sociological and cultural traditions may be more important in producing these differences than sexually determined physiological differences.

Adult↗
PubMed1985

Automatic analysis of surface EMG (preliminary findings in healthy subjects and in patients with neurogenic motor diseases).

Supramaximal electrical stimulation of a motor nerve produces a full contraction of a muscle and the corresponding compound action potential can be recorded. Recent studies appear to support the view that all the motor units are activated during voluntary maximal contraction, at least in the tibialis anterior muscle. The compound action potential and the EMG interference pattern in the tibialis anterior are regarded as two different manifestations of the activation of all the motor units. A method has been developed which compares these EMG activities, by automatic analysis, in order to obtain useful parameters for clinical applications.

Adolescent↗
PubMed1983

EMG responses of the vertical eye muscles to dynamic and static natural vestibular stimulation about different axes in alert rabbits.

The EMG responses of the vertical eye muscles have been recorded in alert intact rabbits submitted to both dynamic and static natural vestibular stimulations about different axes. Following dynamic vestibular stimulation, the phase lead of the EMG response with respect to head position as well as its sensitivity increased with stimulus frequency in all the stimulation modalities. This indicates a progressive recruitment by the stimulus of the second-order vestibular neurons related to semicircular canals. The sensitivity of the response was consistently higher in the effective intermediate roll-pitch modality for all the 4 muscles. Following static stimulation, the EMG response showed an asymmetric modulation. The excitatory response was always higher than the inhibitory one and linearly related with the stimulus. Also for the static stimulation the amplitude of the response was significantly higher when the animal was tilted about the effective intermediate roll-pitch axis for all the 4 muscles. The presence of a maximal EMG response in the same modality for both static and dynamic stimulation indicates a similar spatial organization of those subgroups of ampullar and macular receptors projecting to the same eye muscle.

Acoustic Stimulation↗
PubMed1981

Phase changes induced by ketamine in the vertical vestibulo-ocular reflex in the rabbit.

The effect of ketamine has been tested on the phase of the vertical vestibulo-ocular reflex of rabbits sinusoidally oscillated at various frequencies. A significant phase lag, predominantly affecting the macular component of the reflex, was observed. This action resembles that induced by Nembutal in the same preparation. A specific action of ketamine on synaptic transmission is suggested. Erroneous phase relationship between natural stimuli responses can be obtained in experiments employing ketamine.

Animals↗
PubMed1980

The dynamic discharge properties of oculomotor neurons in rabbits with intact and canal-plugged labyrinths during sinusoidal lateral tilt.

The characteristics of the control exerted by macular and ampullar vestibular receptors on oculomotor neurons (OMN) have been investigated by submitting unanesthetized, encéphale isolé rabbits, with intact and canal-plugged labyrinths, to sinusoidal lateral tilts of varying frequencies (0.013-0.2 Hz). For frequencies of tilt above 0.025 Hz, corresponding to peak angular accelerations suprathreshold for canal related vestibular neurons, both phase and sensitivity of the OMN response differ significantly in the two types of preparation. At lower frequencies of tilt the characteristics of the OMN response are, on the contrary, very similar, thus indicating that also in the intact animals the control of the vertical vestibulo-ocular reflex, in this frequency range, is exerted almost exclusively by the otoliths.

Animals↗
PubMed1979

Behavior of the oculomotor neurons discharge during sinusoidal lateral tilt in the rabbit.

The characteristics of the control exerted by macular and ampullar vestibular receptors on oculomotor neurons (OMN) have been investigated by submitting unanesthetized, encéphale isolé rabbits to sinusoidal lateral tilts of varying frequencies (0.013-0.2 Hz). The phase of the response exhibited a progressive shift towards head velocity with increasing frequencies of tilt. The sensitivity of the OMN significantly increased at frequencies above 0.025 Hz, corresponding to peak accelerations suprathreshold for canals related vestibular neurons. The convergent action of macular and ampullar vestibular receptors in the control of vertical eye movements is discussed in relation with stimulus frequency.

Animals↗