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Biomedical subjects

D Gambi

Publications and source records attributed to D Gambi.

At least 91 records · Page 5Linked to original sources
PubMed1981

Checkerboard reversal pattern and flash VEPs in dialysed and non-dialysed subjects.

In forty-three patients suffering from chronic renal failure (CRF; 32 non-dialysed, 11 dialysed) the flash VEP and the pattern VEP to different spatial (7.5', 15', 30', 60' checks) and temporal (2, 10, 20, 40 Hz) frequencies were investigated. Abnormally delayed flash VEPs were obtained in 53.6% of the cases; transient pattern VEPs had a delayed major positive deflection in 46% of the tested eyes and altered steady-state response in 58% with a total of 65% abnormal responses. Chronically dialysed subjects showed higher levels of altered VEPs for both the techniques. The shorter latencies normally observed with coarser checks in healthy people were maintained in CRF patients, resulting in an abnormal prolongation of the shift between high and low spatial frequencies. Higher statistical correlations linked the pattern VEP with blood urea nitrogen (P less than 0.001) and other renal chemistry than the flash VEP. These and other features could be ascribed to a specific involvement of a maculo-calcarine channel devoted to 'detailed' vision and suggest the usefulness of this method to provide a tool for the early detection of an encephalopathic uraemia.

Adult↗
PubMed1981

Longitudinal study of clinical, neurophysiological and immunological parameters in multiple sclerosis. Preliminary investigation.

Thirty subjects affected with multiple sclerosis, of which 22 were female and eight male, with an average of 30 +/- 7, years were studied, for a period of 10-15 months,. clinically using Kurtzkes' report form, neurophysiologically (responses tested: VEP, BAEP, SEP, ESG) and immunologically (Rosette Et, Ea, EAC). Of the 30 cases, 19 showed poussées in the last three years and 11 were in the stabilization phase. The Kurtzke reports and the neurophysiological tests permitted an accurate assessment of lesion levels and their rate of evolution. The immunological tests showed a notable ability to differentiate between subjects with recent poussées and those in the stabilization phase presenting overall values significantly below the norm. In the follow-up, after treatments with methisoprinol, the immunological tests also revealed modifications of notable interest.

Adult↗
PubMed1981

Neurophysiological abnormalities in uraemic encephalopathy.

Sophisticated electrophysiological assessments have been employed to display cortical alterations in uraemia and to follow the influence of haemodialysis treatment (RDT). Flash-Visual Evoked Responses (VERs); Pattern Reversal Visual Evoked Potentials (VEPs); Brain-stem Auditory Evoked Responses (BAERs); Electroencephalogram (EEG) with Berg's analysis of frequencies were recorded in 15 uraemic patients, 10 of whom subsequently started RDT. VER latency was delayed compared with controls and unmodified after RDT. VEP latency was similarly delayed returning to normal range with RDT. BAER, preliminarily recorded only in 10 patients, showed increased latency of waves I, III, V. EEG showed 7 to 10 and 10 to 13 Hz to be reduced, and after eight months of haemodialysis the 13 to 20 Hz band increased.

Adult↗
PubMed1980

Visual evoked cortical potentials (V.E.C.P.) by television presentation of different patterned stimuli to patients with multiple sclerosis.

Visual pattern reversal evoked potentials constitute a test that can reveal early pathological changes in multiple sclerosis. Sixty nine subjects (52 controls, and 17 patients) were studied with this technique. The transient potentials evoked by checkerboard pattern reversal reveal an increase in the CII peak latency (significantly different from the controls) in M.S., with single elements of 15 and 30 min of arc and 20%-50% of contrast depth. The steady state potentials are absent or show phase lags in some patients with transient responses within the normal limits. The delayed evoked responses are detectable in a high percentage of patients with M.S., even when ocular symptoms are not seen in the clinical observation. Transient and steady-state E.Ps can furnish early tools for evaluation of functionality of visual pathways related to retinal form- and movement-analyzers, the former being sensitive to high spatial frequencies but conducting more slowly than the latter.

Adult↗
PubMed1980

Cephalic and noncephalic references in brain stem-evoked potential recording.

55 controls were studied to investigate the morphology of brain stem evoked potential, utilizing variable electrode arrays. In a first series the active electrodes placed at Cz and subocciput (SO) were referred to the linked earlobes. In a further 15 recording sessions, Cz, SO and A1A2 were connected to a noncephalic (hand) electrode. In the former array there was a reversed and depressed Vth wave in 95% of the cases at SO, while in the latter the peaks were phase and time-locked at all the recording sites coupled to a depressed IV-V complex from SO and A1A2 in respect to Cz.

Acoustic Stimulation↗
PubMed1973

Neuromuscular block after intra-arterially injected acetylcholine. 1. Introduction, methods, and technique.

The neuromuscular depolarizing block induced by intra-arterially injected ACh was studied to determine the variability in the same subject and in different subjects without disorders at the motor end-plate. Amplitude of action potentials of the opponens pollicis muscle evoked by intermittent repetitive supramaximal stimulation of the median nerve at the wrist were recorded for one hour from the beginning of ACh injection. The features of prompt and late depression stages after the injection were analysed statistically. Re-testing of the same subjects after a while shows that, in spite of all efforts to maintain the same experimental conditions, variations do occur in late depression. Time course and duration are particularly affected, while the degree of depression is altered but slightly. The presence of such variations limits this test to evaluation of the influence of other factors only within their already established statistical limits.

Acetylcholine↗
PubMed1973

Neuromuscular block after intra-arterially injected acetylcholine. 2. Effects of ACTH treatments as possible detectors of desensitization level in the receptor site.

It has been suggested that the effect of ACTH in myasthenia gravis may be ascribed to an action involving neuromuscular transmission which favours repolarization processes, with a tendency towards hyperpolarization of the membranes of muscle fibres and motor nerve endings. A similar mechanism has been postulated for the action of ACTH in epilepsy (Klein, 1970). A direct or indirect action on nerve membrane would interfere with depolarization. There is evidence of raised concentration of intracellular potassium and increased outflow of sodium ions which would cause hyperpolarization of the membrane. This paper studies the effect of ACTH on the late block of neuromuscular transmission caused by acetylcholine (ACTH).

Acetylcholine↗