Singlet oxygen induced cerebral vasospasm: an experimental study in rats

A new experimental model is described which can be used as an alternative to study the effects of subarachnoid hemorrhage (SAH) in rats. Vasospasm of the basilar artery is induced photochemically after transpalatal illumination of intracisternally injected rose bengal in two different rat strains. Singlet oxygen, generated in the subarachnoid space, elicits vasospasm which has been demonstrated angiographically at 90 min and 24 h after photosensitisation. Sprague Dawley rats responded better than Wistar rats. Dilution of rose bengal in water was more vasospastic than dilution of rose bengal in artificial CSF. Since the action of singlet oxygen is similar to that of free radicals, this experiment gives an argument for the hypothesis that free radicals play a leading role in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage.     

Loss of constitutional heterozygosity in human astrocytomas

Summary Inactivation of tumour suppressor genes or anti-oncogenes as well as activation of dominant acting oncogenes seem to be important mechanisms in the pathogenesis of gliomas. We compared constitutional and tumoural genotypes at different restriction fragment length polymorphism loci (RFLP) on chromosomes 10 and 17 in 15 unrelated individualsLoss of heterozygosity (LOH) pointing to chromosomal loss or deletions was detected for at least one chromosme 17 marker in 11 gliomas (astrocytomas grades I–III and glioblastoma multiforme), whereas LOH for chromosome 10 loci was only detected in 3 out of 9 cases of glioblastoma multiforme and was not detected in low grade gliomas. Since LOH for chromosome 10 loci seems to be restricted only to glioblastoma multiforme, it is possible that recessive mutations on chromosome 10 are engaged in tumour progression from astrocytomas to glioblastoma multiforme. As LOH of chromosome 17 markers occurs in astrocytomas as in glioblastoma multiforme, chromosome 17 loci probably are involved in early tumour development.     

Intracerebral temperature monitoring in severely head injured patients

Summary In a series of 6 severely head injured patients, intraventricular as well as rectal, bladder and jugular vein temperature is recorded. The relationship between these temperatures in different conditions is evaluated. Intracerebral temperature is 0.5±0.2 °C (mean ± SD) higher than bladder temperature except in conditions such as brain death. It is concluded that rectal temperature is not representative and therefore not a good alternative to the measurement of brain temperature. More data on human intracerebral temperature are mandatory as well as prospective studies correlating intracerebral temperature with final outcome in head injury.     

MR imaging of tuberculous spondylitis.

This case report describes a patient presenting with symptoms of progressive paresis of both legs. An X-ray of the thorax demonstrated an aspect consistent with miliary tuberculosis. Magnetic resonance imaging (MRI) of the thoracic spine revealed medullary compression. The patient underwent a laminectomy and the diagnosis of spinal epidural tuberculoma was made. The patient has been treated with isoniazid, rifampicin and pyrazinamide. After a period of six months, she made a complete recovery.     

Virus Inactivation of Fresh Frozen Plasma by a Solvent Detergent Procedure: Biological Results

In order to increase the safety of blood products, we have developed a procedure for the virus inactivation of fresh frozen plasma. Several batches have been prepared and with the first 10 batches, each of them composed of 60 litres of plasma, we have determined a set of biological parameters. Virus inactivation was realised using TnBP (1%) and Octoxynol 9 (1%). After their elimination with castor oil using chromatography on insolubilized C18 resin, glycine was added and the pH of the plasma was adjusted to 7.4. Plastic bags were aseptically filled with a mean volume of 200 ml of plasma. The mean levels of coagulation factors were all over 0.7 U/ml and their recovery from initial plasma was nearly the same as total protein except for factor VIII:C. The net loss in factor VIII:C was 16%, when including the dilution of plasma. In vivo and in vitro tests demonstrated that in the final product there were no activated factors. As in fresh frozen plasma, the protein concentration was over 50 g/l and the potassium level lower than 5 mmol/l. According to these results, virus-inactivated plasma has the same qualities of fresh frozen plasma and could now replace it.     

Transcranial Doppler sonography in subarachnoid hemorrhage

Ten patients presenting a subarachnoid hemorrhage (SAH) due to rupture of a middle cerebral or an anterior communicating aneurysm are presented. Transcranial Doppler (TCD) values are obtained at different time intervals after SAH. The correlation of TCD values, vasospasm and clinical course is discussed.     

The course of vasospasm following subarachnoid haemorrhage in rats

Summary The course of vasospasm following subarachnoid haemorrhage in rats was studied using vertebrobasilar angiography. Wistar and Sprague Dawley rats were compared with respect to vasospastic response after bleeding. A more pronounced vasospasm was found in Sprague Dawley rats. In order to avoid a possible toxic effect on the contrast medium, only one angiogram per animal was initially performed. However, a comparison with the results obtained in a separate series of non-challenged animals demonstrated a difficulty due to high variability in basilar artery size in the latter group. Therefore, vasospasm can be more readily shown if multiple angiograms are used in the same animal so that the vasospasm can be expressed as a percentage of the initial diameter of the basilar artery. It was found that multiple angiograms are well tolerated when nonionic contrast media are used.     

Haemodynamic,intracranial pressure and electrocardiographic changes following subarachnoid haemorrhage in rats

Summary Experimental induction of subarachnoid haemorrhage in rats resulted in acute haemodynamic changes. Heart rate decreased concomitantly with a rise in arterial blood pressure. Intracranial pressure increased and consequently cerebral perfusion pressure dropped. These changes as well as the observed electrocardiographic (ECG) changes were comparable to those reported in patients. Apart from blood also saline, when introduced into the cisterna magna, was able to elicit such abnormalities. The haemodynamic and electrocardiographic changes, which result from subarachnoid haemorrhage, may even become aggravated, when repetitive injections of blood or saline are given into the cisterna magna and when cerebral angiography is performed prior to induction of the subarachnoid haemorrhage. Chronic intracranial pressure monitoring during the 48 hours following subarachnoid haemorrhage revealed no significant rise in pressure.A thorough control of the experimental conditions is thus of utmost importance in order to give a valid interpretation of the observed anomalies.     

Intracerebral hemorrhage after lumbar myelography with iohexol: report of a case and review of the literature

Intracranial hemorrhage is an uncommon complication of dural puncture. In most instances, hematomas are subdural; they may be unilateral or bilateral. Rarely are intraparenchymal cerebral hemorrhages related to dural puncture. This report describes a delayed occurrence of bilateral intraparenchymal hemorrhages in a 38-year-old woman 7 days after lumbar myelography with iohexol. A review of the literature is presented.