Biomedical subjects
Publications and source records attributed to G Beltrami.
Age-related physiological changes alter drug responsiveness in the elderly. The changes of pharmacokinetics are widely known but they do not explain completely the altered drug action in the elderly. In this work the authors deal with the alterations of pharmacodynamics which could be responsible for the different pharmacological action and the high frequency of side effects which can be found in old age.
The latency of saccadic eye movements evoked by the presentation of auditory and visual targets was studied while starting eye position was either 0 or 20 deg right, or 20 deg left. The results show that for any starting position the latency of visually elicited saccades increases with target eccentricity with respect to the eyes. For auditory elicited saccades and for any starting position the latency decreases with target eccentricity with respect to the eyes. Therefore auditory latency depends on a retinotopic motor error, as in the case of visual target presentation.
We studied saccadic and smooth pursuit eye movements in 24 patients suffering from multiple sclerosis during disease worsening, before and after high-dose 6-methylprednisolone infusions. Quantitative evaluation of saccades was based on amplitude/duration and amplitude/peak velocity relationships, precision (i.e. the ratio of actual to desired saccade amplitude) and the latency, whereas smooth pursuit eye movements were studied using target velocity/performance index relationship. At basal recordings, 22/24 (91.7%) of the patients showed at lest one abnormality. Eleven of the 24 patients (45.8%) showed modification of one or several parameters: improvement in 6 patients, worsening in 2, coexistence of both trends in 3. Latency improvement was the only significant modification when patients were considered as a group. Neurophysiological modifications did not correspond to clinical changes.
The electrooculographic technique was used to record smooth pursuit eye movements in 71 healthy subjects homogeneously distributed within an age range between the 2nd and the 6th decades. The target moved at constant velocity (triangular ramps) and 9 different target velocities (V), from 10 deg/s to 50 deg/s were considered and presented according to pseudorandom sequence. Ad hoc software suppressed catch-up saccades so that a pursuit index (PI) value was computed for each ramp taking into account only the smooth pursuit tracking modality. It was demonstrated that the relationship between V and PI could be described by the linear model PI = a + b * V. Pursuit index was proved to be influenced by the age of subject (decade factor in the analysis of variance), since an almost linear increase in b values yields a reduction of pursuit index values. The method was tested in 22 multiple sclerosis patients and an association was found between the occurrence of cerebellar signs and the reduction of a value.
PURPOSE: The authors evaluated the reliability of the coefficients of the (1) amplitude/duration and (2) amplitude/peak velocity relationships of the mean precision values and the mean latency values (saccadic eye movements) and the coefficients of the target velocity/gain relationship (smooth pursuit eye movements). They computed test-retest maximum variability limits for these parameters. METHODS: After a 1-week interval, saccadic and smooth pursuit eye movements were recorded twice from 20 healthy subjects; 12 of these subjects underwent a third recording session. The estimate of the intraclass coefficient of reliability, R, was adopted to evaluate the reliability of eye movement quantitative analysis. RESULTS: The data demonstrated that the reliability was fairly good for the amplitude/peak velocity relationship, was good for the precision, and was excellent for the amplitude/duration, the target velocity/gain relationships, and the latency. CONCLUSIONS: Quantitative analysis of both saccadic and smooth pursuit eye movements is reliable. One statistic used to estimate reliability, ie, the within-subjects mean square value, also enables the determination of test-retest normal variability values for both the variances and the differences of measurements.
118 cases of traumatic lesions of the liver have been reviewed. The patients were admitted to the First Aid and Emergency Surgery Division of Niguarda General Hospital between 1965 and 1976. The statistico-clinical data were elaborated in accordance with classical subdivisions of each disease form and compared and discussed, as far as possible, with similar data provided by the recent literature. Stress is laid on the increase in the number and gravity of cases in recent years, the prevalent localization of lesions in the right lobe, the importance of trauma pathogenesis for diagnostic and therapeutic purposes, and diagnostic difficulties. The importance of peritoneal probing and dialysis and of the examination for bile salts in the urine are underlined. As for treatment, the various surgical techniques are mentioned and discussed in relation to the characteristics of the traumatic lesion; the commonest technique was simple suture of the break in the liver parenchyma. Mortality was 33.05%. The cause of death in the 39 cases is mentioned.
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Between 1989 and 1994 free gracilis muscle reinnervation was used to treat three patients severely affected with Volkmann's syndrome of the forearm. All three patients were males and they had supracondyloid fracture of the humerus, treated nonsurgically an average of 7.6 years previously. Mean age at the time of surgery was 19.3 years. The flap was transplanted in flexor function of the fingers in two of the patients, in extensor function of the wrist in one. Electromyography and successive clinical monitoring revealed an increase in contractile strength up to one year after surgery. In the first two cases final hold strength exceeded by more than 50% that of the contralateral limb, in the third case excursion of the wrist which could not be quantified, but which was useful for elementary activities was recovered. When myotendinous units for transplantation are not available, free gracilis muscle reinnervation constitutes a valid surgical solution in cases of severe Volkmann's syndrome of the forearm.
Eye-head coordination during gaze orientation toward auditory targets in total darkness has been examined in human subjects. The findings have been compared, for the same subjects, with those obtained by using visual targets. The use of auditory targets when investigating eye-head coordination has some advantages with respect to the more common use of visual targets: (i) more eccentric target positions can be presented to the subject; (ii) visual feedback is excluded during the execution of gaze displacement; (iii) complex patterns of saccadic responses can be elicited. This last aspect is particularly interesting for examining the coupling between the eyes and the head displacements. The experimental findings indicate that during gaze orientation toward a visual or an auditory target the central nervous system adopts the same strategy of using both the saccadic mechanism and the head motor plant. In spite of a common strategy, qualitative and quantitative parameters of the resulting eye-head coordination are slightly different, depending on the nature of the target. The findings relating to patterns of eye-head coordination seem to indicate a dissociation between the eyes and the head, which receive different motor commands independently generated from the gaze error signal. The experimental findings reported in this paper have been summarized in a model of the gaze control system that makes use of a gaze feedback hypothesis through the central reconstruction of the eye and head positions.
Some reports suggest that immunologic mechanisms may play a role in the pathogenesis of anemia in idiopathic myelofibrosis (IMF). Herein we report the case of a transfusion dependent IMF patient with psoriasis in whom cyclosporin-A (CyA) treatment for skin lesions (200 mg/day) was associated with long-lasting correction of anemia. After 2 months of CyA therapy the patient's Hb level increased and he became transfusion free in 4 months. After 12 months immunosuppressive therapy was discontinued due to renal toxicity, yet the Hb level remained stable for an additional 12 months. The patient is currently being administered CyA at a reduced dosage because of mild renal impairment along with transfusional support consisting of a median of 2 red cell units/month. Altogether the patient received no transfusional support for 36 months. This case, as well as other reports, suggests that the issue of immunosuppressive treatment in IMF anemia deserves further investigation.