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Biomedical subjects

N Accornero

Publications and source records attributed to N Accornero.

64 records · Page 4Linked to original sources
PubMedDate not supplied

Changes in color vision after a single dose of vigabatrin or carbamazepine in healthy volunteers.

In patients with epilepsy the older antiepileptic drugs induce distinct electroencephalographic changes and may also alter visual function. Although the effects of the newer antiepileptic drugs on the electroencephalogram remain less clear, long-term treatment with vigabatrin (VGB) has been reported to induce severe and permanent visual impairment. Our aim in this study was to investigate the effects of a single oral dose of VGB and carbamazepine (CBZ) on visual function in normal healthy volunteers randomly assigned to three groups according to a single-blind, placebo-controlled design. All subjects underwent color visual evoked potential tests and color perimetry at baseline and after receiving placebo, VGB (2,000 mg) or CBZ (400 mg). Whereas CBZ induced a mild overall impairment of the chromatic and achromatic systems, VGB induced a selective blue impairment. The differential changes the two antiepileptic drugs induced in visual tests presumably depend on their different mechanisms of action. The selective blue impairment in color visual tests in VGB-treated healthy subjects is consistent with gamma-aminobutyric acid (GABA)-ergic inhibition also at retinal level. Hence, color visual tests may be suitable to detect initial visual abnormalities in VGB-treated patients with epilepsy.

Adult↗
PubMedDate not supplied

Clinical and electroencephalographic effects of topiramate in patients with epilepsy and healthy volunteers.

Although topiramate, one of the newer drugs used in treating epilepsy, is effective in reducing seizure frequency and has a wide spectrum of action, it often induces intolerable adverse effects, predominantly related to the central nervous system. Information that would help document adverse reactions early, thus allowing topiramate doses to be adjusted during the drug titration and maintenance phases, could be obtained from electroencephalogram (EEG) studies. We studied the clinical effects and EEG changes induced by topiramate in patients with refractory partial epilepsy receiving the drug as add-on therapy. To exclude effects related to the other drugs and to epilepsy itself, we compared data from patients and healthy volunteers. After receiving topiramate, 22.6% of patients became seizure free and 29% had their seizures reduced by 50% or more. Topiramate nevertheless induced noteworthy adverse reactions, the main problems being sedative and cognitive changes. Also, in healthy volunteers, a single 100-mg dose of topiramate induced mild adverse reactions, mainly affecting concentration and attention, with difficulties in speech and writing. In patients with epilepsy, the EEG changes induced by topiramate consisted of increased delta and theta activities and decreased activity in the rapid bands. This recognizable topiramate-induced EEG pattern was again evident in the healthy volunteers, in whom we also detected a significant reduction in the alpha frequency rhythm. Our results confirm that topiramate needs to be introduced gradually while patients undergo close neuropsychologic and neurophysiologic monitoring to detect adverse sedative and cognitive reactions early. The EEG correlate of these events seems to be increased activity in the slower frequency bands.

Adult↗
PubMedDate not supplied

[Congenital analgesia].

The case of a 12 years old boy with a congenital anaesthesia covering all cutaneous and visceral districts is reported. There were no other neurological abnormalities apart a light mental retardation and loss of axon reflex after intradermal injection of hystamine. Notwithstanding this last finding a diagnosis of congenital indifference to pain was made. The differential diagnosis between indifference and insensitivity to pain is discussed.

Axons↗
PubMedDate not supplied

[Plasma, intraerythrocytic and spinal fluid amino acid levels in a case of ulcero-mutilating acropathy].

In a patient affected by Thevenard's disease (degenerative disease of the spinal ganglia and posterior roots) we measured levels of intraerythrocytic, plasmatic and cerebrospinal fluid aminoacids. In the plasma we found an increased concentration of taurine and glycine, expression of hypercatabolism, which was confirmed by the presence of a decreased level of the free intraerythrocytic aminoacids. In the cerebrospinal fluid we found increased concentrations of methionine, valine and lysine which indicates the presence of an enzymatic inhibition that involves the systemic transport of aminoacids at the barrier level. The increased levels of glutamic acid and arginine suggests an alteration of the synthesis of alpha-guanino butyric acid. We have also found an increase in the levels of valine, methionine, glycine, tyrosine which suggests the presence of an enzymatic alteration in the collateral reactions that biochemically feed into the Krebs cycle. The authors therefore conclude that the basis of this disease may be found in a metabolic defect biochemical synthesis.

Amino Acids↗
PubMedDate not supplied

[Ulcero-multilating acropathy].

A case of a 46 years old male suffering from chronic sensory neuropathy is reported. The symptoms consisted of superficial and deep sensory disturbances, and bilateral trophic plantar ulcerations with osteolysis, resulting in a deformity of the feet. There was an increased sweating of the distal portions of the four limbs, and a delayed adaptation of blood pressure and heart frequency to postural changes. CSF aminoacids were all increased except taurine, which was markedly descreased. An increased blood flow in lower extremities was demonstrated angiographically. The possibilities of pharmacological and surgical treatment raised by the hemodynamic hypothesis of BUREAU and BARRIERE (1957) are discussed.

Bone Resorption↗