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Biomedical subjects

J Castillo

Publications and source records attributed to J Castillo.

At least 253 records · Page 14Linked to original sources
PubMedDate not supplied

Aggravation of acute ischemic stroke by hyperthermia is related to an excitotoxic mechanism.

OBJECTIVE: To examine whether hyperthermia aggravates cerebral injury in acute ischemia by an excitotoxic mechanism, we studied the relationship between body temperature on admission and CSF concentrations of neuroexcitatory amino acids in 128 patients with acute ischemic stroke of less than 24 h duration. METHODS: Stroke worsening was defined as the percent change between the Canadian Stroke Scale (CSS) at 48 h and the CSS on admission. Infarct volume was measured on days 4-7 on cranial computed tomography. Excitatory amino acids were analyzed using HPLC. RESULTS: Glutamate concentration [median (min.-max.)] was 11 (2-19) micromol/l in hyperthermic patients (body temperature >37.5 degreesC) and 5 (2-22) micromol/l in normothermic patients (p < 0.0001). Glycine concentration in hyperthermic and normothermic patients was 16 (3-21) micromol/l and 9 (3-50) micromol/l, respectively (p < 0.0001). Glutamate was significantly higher in patients with hyperthermia only during the first 12 h after the onset of symptoms. The CSF concentrations of glutamate (r = 0.52; p < 0.0001) and glycine (r = 0.62; p < 0.0001) correlated with body temperature. Body temperature was significantly related to stroke worsening and infarct size, but this effect was dependent on the glutamate effect. CONCLUSION: Glutamate and glycine release during the acute phase of cerebral ischemia could be responsible for the increased brain damage in hyperthermia.

Acute Disease↗
PubMedDate not supplied

Serum amino acid levels after permanent middle cerebral artery occlusion in the rat.

BACKGROUND AND PURPOSE: High levels of glutamate in plasma and cerebrospinal fluid (CSF) have been demonstrated in patients with acute ischemic stroke. Whereas this glutamate increase in CSF is only evidenced during the first 6 h in stable ischemic stroke, it is sustained for 24 h in progressing stroke. The aim of this investigation was to study the evolution of serum glutamate levels after stroke in a rat model of permanent cerebral artery occlusion. METHODS: Glutamate, glycine, aspartate, taurine and tryptophan were measured by high-performance liquid chromatography from serum samples taken before and at different times after permanent middle cerebral artery occlusion (MCAO) and from sham-operated rats. RESULTS: After MCAO, a 3-fold increase in glutamate and a 2-fold increase in glycine and aspartate were observed in rat serum. The onset of this amino acid increase began 4-6 h after ischemic induction, reached peak values at 8-24 h and returned to preischemic values by 48-72 h. Serum concentrations of taurine and tryptophan were not modified after MCAO. Sham-operated rats did not exhibit changes of basal amino acid concentrations in serum. CONCLUSIONS: The serum excitatory amino acid profile in this experimental model confirms that the early detection of increased concentrations of glutamate and glycine at systemic circulation observed in patients with acute stroke is a consequence of the cerebral ischemic process.

Acute Disease↗
PubMedDate not supplied

Nasolacrimal polyurethane stent placement: preliminary results.

PURPOSE: To present our initial results in the treatment of nasolacrimal obstruction by placing a polyurethane stent. METHODS: 74 nasolacrimal stents were implanted under fluoroscopic guidance in obstructed nasolacrimal systems of 64 patients. Dacryocystography and CT were used to verify the position and patency of the stents. Mean follow-up was 15 months. Clinical examinations were done at the first week, first month, third month and sixth month after stent placement. RESULTS: Polyurethane stents were successfully inserted and permeable in 59 patients (92.1%), but could not be inserted in 5 patients (7.8%). Epiphora was solved and permeable in 53 cases (82.8%), it was not permeable but asymptomatic in 2 cases (3.1%), and was not permeable but symptomatic in 4 (6.2%). In 5 cases (7.8%) stents remained permeable although patients complained of epiphora. CONCLUSIONS: Polyurethane stent placement is a non-invasive technique that can replace dacryocystorhinostomy, giving better results and tolerance.

Adolescent↗
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Burn scar carcinoma.

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Animals↗
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[Physiopathology of cerebral ischemia].

INTRODUCTION: Knowledge of physiopathological mechanisms permits understanding of neuro-imaging changes during the various phases of cerebral ischaemia and the mechanisms of action on which many aspects of treatment are based. DEVELOPMENT: The physiopathology of cerebral ischemia is different in the white and grey matter of the brain. In the grey matter, obstruction of a blood vessel causes an ischemic gradient. In the more peripheral zones, known as the ischemic penumbra, functional alterations occur in the neurons and the glia, although the structural integrity is maintained for some time. Liberation of glutamate and the entrance of calcium into the cells leads to a series of biochemical processes which end in neurone death. In the white matter, loss of energy alters the direction of the ion exchange pumps, resulting in calcium entering the axon. Liberation of GABA activates specific receptors which protect the nerve fibres from the consequences of anoxia. CONCLUSIONS: The cerebral oedema which accompanies ischemia has a double mechanism: initially it is cytotoxic and then vasogenic. Both contribute to increase the neurological damage caused by cerebral ischaemia.

Animals↗