[Magnesium in cerebrospinal fluid in acute cerebral ischemia: its relation to glutamate neurotoxicity]

INTRODUCTION

In animal models it has been shown that there is an increase in tissue magnesium concentration during cerebral ischemia. We studied the changes in magnesium levels in the cerebrospinal fluid (CSF) during the acute phase of cerebral ischemia.

MATERIAL AND METHODS

We included 95 patients with first ischemic cerebral infarcts admitted to hospital within the first 24 hours and also 37 controls. CT scan was done on admission and between four and seven days later (when the volume of the infarct was determined). The neurological defect was evaluated on the Canadian scale on admission, after 48 hours, on the seventh day and after three months. The CSF magnesium concentration was determined using a colorimetric method and the glutamate by HPLC.

RESULTS

The CSF magnesium concentrations were significantly higher in the patients than in the controls (2.6 +/- 0.6 mmol/l vs 2.2 +/- 0.6 mmol/l p = 0.0001). The magnesium concentration was higher in the larger infarcts (Pearson's coefficient = 0.2901, p = 0.0043), and in those presenting greater neurological defects after 48 hours (Spearman's coefficient = -0.4649, p < 0.0001). The magnesium concentration was not related to the presence of early signs on the initial CT scan and the Canadian scale rating on admission. The concentration of magnesium was significantly correlated with that of glutamate (Pearson coefficient = 0.7735, p < 0.0001).

CONCLUSIONS

The levels of magnesium in the CSF were satisfactorily related to the volumes of the infarct and the intensity of the neurological defect. However, this association was late, occurring more than 48 hours after onset of the condition.

[Time for cerebral damage due to hyperglycemia in acute ischemia]

INTRODUCTION

Hyperglycemia increases morbimortality in cerebral infarcts. In animal models, this relationship is only seen during the initial moments of cerebral ischaemia. The time needed in humans for cerebral damage to occur due to hyperglycemia is not known.

MATERIAL AND METHODS

We included 194 patients admitted within 24 hours of the start of their first clinical episode of cerebral hemisphere infarction. The glucemia was determined on admission and after 24, 48 and 72 hours. The neurological defect was evaluated on the Canadian scale on the seventh day. The volume of the infarct was determined on a second CT scan done between the fourth and seventh days after the episode.

RESULTS

There was a positive association between the volume of the infarct and the glycemias on admission and after 24 hours, but this was not seen in later determinations. The difference in scoring, on the Canadian scale, on the seventh day, between patients with glycemias above or below 120 mg/dl decreased from the time of admission up to the time samples were taken 72 hours later. However, statistical significance persisted during the whole period studied. Nevertheless, in a logistic regression model, the glycemia on admission was the only determination associated with the Canadian scale on the seventh day (OR = 1.02; IC 95% = 1.01-1.02).

CONCLUSIONS

There is a clear association between hyperglycemia and the worst stage of the infarct, and this is most intense in the first hours after onset of the clinical features.

Neuroexcitatory amino acids and their relation to infarct size and neurological deficit in ischemic stroke

BACKGROUND AND PURPOSE

The participation of excitatory amino acids (EAAs) in the pathogenesis of ischemic neuronal lesion has been experimentally demonstrated, but clinical experience is scarce. Our objective was to examine EAA levels during the acute phase of cerebral infarction in relation to infarct size and intensity of neurological deficit.

METHODS

Using high-performance liquid chromatography, we determined the glutamate, aspartate, taurine, and glycine concentrations in the plasma and cerebrospinal fluid (CSF) of 128 patients with ischemic cerebral infarction confirmed by CT and 43 control subjects. Blood and CSF samples were obtained on admission within the first 24 hours from symptom onset. The severity of the neurological deficit was assessed with the Canadian Stroke Scale immediately after these tests and at 48 hours after inclusion in the study. Infarct volume was determined in a second CT performed between the 4th and 7th day after the patient's inclusion.

RESULTS

The concentration of plasmatic glutamate was 121.39 +/- 80.89 mumol/L in the control group and 163.71 +/- 103.13 mumol/L in the patient group (P = .015); in CSF it was 3.46 +/- 1.20 mumol/L in control subjects and 6.55 +/- 4.65 mumol/L in patients (P < .0001). The concentration of glycine in plasma was 158.02 +/- 32.15 mumol/L in control subjects and 189.37 +/- 74.04 mumol/L in patients (P = .007); in CSF it was 6.18 +/- 2.28 mumol/L in control subjects and 11.23 +/- 6.96 mumol/L in patients (P < .0001). The concentrations of glutamate in plasma and in CSF were significantly higher in patients with large cerebral infarcts and in those with cortical infarcts. Levels of glutamate and glycine in plasma and CSF were significantly higher in patients with a higher degree of neurological deficit.

CONCLUSIONS

Our results support the excitotoxic activity of glutamate and glycine in patients with cerebral infarction.

[The prognostic value and evolution of blood pressure during an acute phase of stroke]

We studied the prognostic influence and evolution of blood pressure during the acute phase of stroke in 89 patients (50 men and 39 women) with an average age of 69.4 +/- 10.8 years. Seventy-two were diagnosed as having ischaemic infarct and 17 as having spontaneous intracerebral haemorrhage. Blood pressure was taken every four hours for twelve days. Clinical situation was evaluated using the Rankin scale. Systolic and diastolic blood pressure progressively decreased without needing any medication in the first two weeks of evolution. The decrease was greatest in hypertense patients and in those with left ventricle hypertrophy. We found the initial figures for systolic and diastolic blood pressure significantly higher in those patients with brain infarct who had not died and in those in a better functional position the second week of evolution. Blood pressure did not influence the prognosis of intracerebral haemorrhage patients.

Cerebrospinal fluid tyrosine and 3,4-dihydroxyphenylacetic acid levels in migraine patients

We studied biochemical parameters related with central dopaminergic neurotransmission in migraine patients during crisis. We determined tyrosine and 3,4-dihydroxyphenylacetic acid (DOPAC) levels in cerebrospinal fluid (CSF) of 47 patients, 29 suffering migraine without aura and 18 suffering migraine with aura, comparing them with 27 control subjects. Tyrosine levels did not differ significantly between patients and controls. The CSF concentration of DOPAC was 0.73 +/- 0.55 ng/ml in the control population, 3.84 +/- 2.08 ng/ml in patients with migraine without aura and 3.30 +/- 1.49 ng/ml in patients suffering migraine with aura. The concentration of DOPAC correlated positively with the intensity of headache. These results suggest that patients with migraine have a central dopaminergic hyperfunction, probably related to a coexisting central dysfunction of noradrenergic neurotransmission.

[The prognostic value of analytical hemorheological factors in stroke]

Plasmatic hyperviscosity is a known vascular risk factor which depends, among other parameters, upon total proteins, haematocrit value and fibrinogen. The aim of this study was to determine the relationship between these analytical haemorrological parameters and mortality and acute stroke sickness rate. We studied 216 patients with brain infarct and spontaneous intracerebral haemorrhage out of a sample of 256 acute stroke patients. We evaluated neurological affectation using the Canadian scale upon admission, on the seventh day and after three months. We determined plasmatic haemorrological factors (haematocrit, fibrinogen and total proteins) upon admission and again after one week and then at three months High fibrinogen levels in plasma were related to brain infarct mortality regardless of the cause of death.