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Biomedical subjects

A Polo

Publications and source records attributed to A Polo.

14 recordsLinked to original sources
PubMed1992

Retinal oscillatory potential abnormalities in patients with chronic renal failure, before and after dialytic treatment.

Nineteen patients with chronic renal failure were studied, oscillatory potentials (OPs) being recorded shortly before and after dialytic treatment. Mean values of either onset latency (O1 latency) and duration of the complex (O1-N4 inter-peak latency) were found to be significantly longer in patients than in controls (p < 0.001). Most of the patients (12) showed a pathological prolongation of latency (> 2.5 SD). Amplitude changes also affected OPs, but earlier components were reduced to a lesser degree than the later ones, as shown by statistical analysis. Moreover, seven patients showed an almost complete loss of O3 and O4 peaks. Latency changes may be transiently reversed by dialysis, suggesting a functional impairment of the retinal response; the loss of later components is a more persistent abnormality probably related with a structural damage.

Adult↗
PubMed1992

Polyneuritis cranialis: clinical and electrophysiological findings.

A 13 year old boy, developed bilateral facial weakness, dysphonia and dysphagia acutely after a febrile illness. Neurological examination and MRI of the brain were normal. The CSF protein level increased. Blink reflex monitoring during clinical recovery was consistent with demyelination of the lower cranial nerves innervating the branchial arch musculature, a rare variant of Guillain-Barré syndrome.

Adolescent↗
PubMed1992

Evoked potentials before and after anemia correction with recombinant human erythropoietin in end-stage renal disease.

Subclinical involvement of the nervous system in uremic adults has been detected by modern neurophysiological techniques. Chronic anemia is one of the possible factors responsible for neural dysfunction in uremia. We evaluated neurophysiological (brainstem auditory and somatosensory evoked potential) abnormalities and their possible modification following anemia correction with recombinant human erythropoietin in 14 children with end-stage renal disease maintained by hemodialysis. Only peripheral and 8th cranial nerve electrophysiological data are significantly abnormal in our patients, and they are not acutely modified by anemia correction. These data confirm the importance of electrophysiological testing of uremic children for detecting nervous system involvement at an early stage and for monitoring the efficacy of its management.

Adolescent↗
PubMed1992

[Determination of basal and stimulated blood gastrin in duodenal ulcer].

Serum gastrin levels were measured under basal conditions and after hyperproteic meal stimulation in 24 patients with non-stenotic duodenal ulcer, 78% of them were males with a mean age of 36.4 years. Results were compared with those obtained in 20 volunteers. Basal gastrin levels in patients with duodenal ulcer 46.2 +/- 17.5 pg/ml did not show any significant statistical differences when compared with those in the control group (51.01 +/- 28.1 pg/ml). After meal stimulation gastrin levels at different time intervals, were similar in patients with duodenal ulcer and in the control group. We conclude that serum gastrin does not seem to play a relevant pathogenic role in the development of duodenal ulcer; its measurement is of no value as a biological marker of duodenal ulcer disease.

Adult↗
PubMed1991

Irreversible respiratory failure in an achondroplastic child: the importance of an early cervicomedullary decompression, and a review of the literature.

The authors report the case of a girl with achondroplasia suffering from a progressively worsening hypotonic quadriparesis. CT scan showed slight dilatation of ventricular and subarachnoid spaces, with well-defined evidence of cortical sulci and gyri. This aspect was compatible with the diagnosis of macrocrania and megalencephaly (CP being 51 cm). The foramen magnum was narrowed, the transverse diameter measuring 15 mm and the 50th percentile being, for age, 26 mm. Somatosensory evoked potentials (SEPs) revealed bilaterally prolonged interpeak latencies Erb-N13, slowing of central conduction time N13-N20 from right median nerve stimulation, and block from left median nerve. The suspicion of cervicomedullary compression was confirmed by MRI, showing a very marked stenosis with compression exerted by the odontoid process. Further, a stenotic cervical canal and optic nerves verticalization were manifest. The patient underwent neurosurgical decompression by suboccipital craniectomy and cervical-C1 laminectomy. In spite of treatment, both neurologic and respiratory problems (rapid, shallow and almost abdominal breathing) were unchanged. The girl died 4 1/2 months later. The authors emphasize the important role of SEPs in detection of cervicomedullary compression in achondroplastic children and also stress the necessity of an early surgical treatment as the only condition for possible clinical improvement and/or full recovery.

Achondroplasia↗
PubMed1990

Far-field and cortical somatosensory evoked potentials in motor neuron disease.

We examined median somatosensory evoked potentials (SEPs) in 26 patients with sporadic motor neuron disease (MND). SEPs were recorded with multiple scalp derivations, using both the midfront and the earlobe as references for each subject. Central conduction time (CCT) was abnormal in three patients, but only when using the midfront reference. Moreover, an exclusive alteration of the early prerolandic potentials (absent or delayed P20 and/or P22) was noted using the earlobe reference in amyotrophic lateral sclerosis and in progressive bulbar palsy (54% and 50% of patients, respectively) but not in progressive muscular atrophy. These findings correlated with clinical evidence of upper motor neuron signs and with the severity of the disease. In agreement with recent views regarding the sources of the early anterior cortical responses, neuronal loss in the motor cortex may be considered as affecting the generator sites of these potentials.

Adult↗
PubMed1990

AIDS--associated predominantly sensory neuropathy. The role of herpes viruses.

Three patients with predominantly sensory neuropathy in course of HIV-1 infection are reported. In all cases ultrastructural examination showed herpes virus-like particles in the axoplasmic matrix of myelinated fibers and in endoneurial macrophages. In 2 cases clinical patterns of posterior column involvement were observed.

Acquired Immunodeficiency Syndrome↗
PubMed1988

[Continuous muscular activity. Clinical aspects and neurophysiological differences from Isaacs' syndrome].

We report a case of continuous muscle activity, unusual from both the clinical and neurophysiological point of views. The neurological examination revealed a continuous rippling of muscles, but limited to the lower part of the face, to the forearm and to the muscles of the thenar eminence. All deep reflexes were normal. Hyperperspiration, spasms and stiffness of abnormal postures were absent. Electromyography displayed continuous motor unit discharges. An abnormal F wave was elicited only from the affected territories. The disappearances of the spontaneous activity and of the F wave occurred not only after the motor nerve block, but also after the block of the afferent sensitive fibres. Therapy with carbamazepine, hydantoin, diazepam and baclofen did not bring improvement.

Action Potentials↗
PubMed1977

A computer program for the analysis of controllability, observability and structural identifiability of biological compartmental systems.

A computer program to check structural identifiability of biological compartmental systems, that is the priori possibility of estamating all unknown system parameters through a multi input-multi output tracer experiment is presented. The procedure, as based only on the adopted compartmental structure and the chosen input-output experiment, is independent of the numerical values of the parameters: therefore the program can be usefully employed before parameter estimation algorithms, to assure that all the unknown parameters evidenced in the model can be estimated from the experimental data. After a short review on compartmental models, controllability observability and structural identifiability are defined and techniques to check them are provided. The digital computer implementation of the whole procedure is discussed in detail. Some typical program runs regarding the application to biological systems are given.

Computers↗
PubMedDate not supplied

[Comparative study in pediatric inhalation anesthesia. Clinical characteristics and anesthetic complications with halothane and isoflurane].

OBJECTIVES: Comparative study of clinical characteristics and complications during induction, maintenance, and recovery in pediatric inhalational anesthesia between two commonly used fluoride agents (halothane and isoflurane). MATERIAL AND METHODS: We studied 66 children aged 1 month to 13 years undergoing general anesthesia for short lasting surgery who were divided into two groups of 33 patients each one: Isoflurane group and halothane group. Induction and maintenance anesthesia was performed with the corresponding inhalant agent. Parameters measured were duration of unconsciousness, time elapsed for intubation and recovery, heart rate, arterial blood pressure, and incidence of complications. RESULTS: Children anesthetized with isoflurane showed a shorter period of unconsciousness (1.55 +/- 0.11 min) than those anesthetized with halothane (1.91 +/- 0.12 min); whereas that the time required for intubation was significantly more prolonged (8.94 +/- 0.51 and 6.57 +/- 0.32 min, respectively). The incidence of complications was higher in the isoflurane group, mainly expressed as laryngeal spasm during the induction period. Both groups of patients showed a similar hemodynamic behaviour, although diastolic arterial pressure during maintenance anesthesia was significantly lower with isoflurane. Anesthesia recovery was faster and more predictable with isoflurane than with halothane. CONCLUSIONS: Anesthetic agent isoflurane is less appropriate than halothane for induction in pediatric anesthesia due to a high incidence of complications, specially laryngeal spasm.

Administration, Inhalation↗
PubMedDate not supplied

[Pressure changes in the pneumoballoon of several endotracheal tubes after the administration of nitrous oxide].

We compare the degree of nitrous oxide diffusion in three types of endotracheal tubes available in the market, by means of continuous monitoring of the pressure attained at the pneumoballoon. Among the systems designed to impede or to minimize nitrous oxide diffusion, we have used in this study the so called "rediffusion system". When the endotracheal tube possesses this system, the pressure attained at the pneumoballoon remained constant throughout the study period (23.2 +/- 0.53 mmHg at time zero vs 24.2 +/- 0.66 mmHg 50 min after administration of protoxide). In contrast, endotracheal tubes without "rediffusion system" showed a statistically significant increase (p less than 0.05) of pneumoballoon pressure (25.2 +/- 2.43 mmHg and 26.7 +/- 1.01 mmHg at time zero vs 45.2 +/- 3.12 and 44.3 +/- 2.41 mmHg 50 min after protoxide administration in the two other types of endotracheal tubes). We believe that during anesthesia with nitrous oxide the pneumoballoon pressure should be monitored or systems that avoid diffusion of this inhalational agent should be inserted. Our results indicate that endotracheal tubes equiped with "rediffusion system" are effective in impeding diffusion of the inhalational agents.

Adult↗
PubMedDate not supplied

[Retinal oscillatory potentials in the study of retinopathy in dialyzed subjects with chronic renal insufficiency].

Oscillatory potentials (OP) were recorded from 24 patients with chronic renal insufficiency undergoing hemodialysis. Nobody had visual disturbances. Abnormal OP were found in 11 (45.8%) patients. Moreover the possible correlations among the abnormal OP and some biochemical and clinical parameters were studied. The Authors emphasize the usefulness of the OP to disclose the subclinical retinopathy of the patients with renal insufficiency.

Adult↗
PubMedDate not supplied

Assessment of autonomic functions in insulin-dependent diabetic children and adolescents.

Autonomic function has been studied in 30 insulin-dependent diabetic children and adolescents, through five cardiovascular tests. A significant difference between the diabetic and the control subjects was found in heart rate variations after deep breathing and after standing. Fifty percent of our patients showed an altered response to one or more cardiovascular tests. Although clinical manifestations of autonomic dysfunction are not frequent in young insulin-dependent patients, early signs of functional alterations are detectable in a high percentage of them.

Adolescent↗