Vol 2, No 3 (2008)

The comparative analysis of pathogenic mechanisms of ischemic stroke in patients with and without Patent Foramen Ovale (PFO) was performed. 101 patients with cryptogenic stroke and stroke of known etiology were examined. All patients underwent a diagnostic protocol including brain CT/MRI scan, haemostatic system testing, ECG, standard echocardiography, transthoracal echocardiography with bubble test and transcranial Doppler with bubble test; 51 patient underwent transesophageal echocardiography. PFO was found in half of the patients with ischemic stroke. However, the paradoxical cerebral embolism could not be considered as a main stroke risk factor in the studied cases: the mechanism of stroke in PFO was clarified with the same frequency, as in patients without PFO. So, in the presence of other competing risk factors of cerebral lesion, PFO does not play independent pathogenic role in the genesis of brain ischemia.

Therapeutic drug monitoring is an important part of antiepileptic therapy, and the search for alternative non-invasive methods of such monitoring represents an actual task for clinical neurology. For this purpose, we determined by gas chromatography and mass spectroscopy the levels of the anticonvulsant carbamazepine in the plasma and saliva of healthy volunteers aged 18–25 years after one oral dose of 200 mg. Maximal drug concentration was 2.6–2.7 µg/ml in the plasma and 0.75 µg/ml in the saliva; mean saliva/plasma drug level ratio was 0.3. Time necessary to reach maximal concentration was 6–7 hrs for both plasma and saliva. T1/2 was also equal for both sources: 15–16 hrs. Significant correlation between the plasma and saliva carbamazepine concentrations was revealed (R2=0,893). Thus, while treating epilepsy patients with carbamazepine, it is possible to use the saliva as an adequate biological sample for conducting non-invasive drug monitoring.

We assessed the morphological changes induced by intraventricular haemorrhage (IVH) and investigated the effects of intraventricular fibrinolytic treatment following IVH. The experiment was performed in 30 Wistar rats. In first (control) group (15 rats) animals received intraventricular injection of 40 microl autologous blood with 10 microl normal saline. In second group (15 rats) 40 microl autologous blood with 10 microl t-PA recombinant tissue plasminogen activator (t-PA) was injected in ventricular of the animals. Morphological examination of the brains were carried out 2 days and 21 days following IVH. Marked losses of the ependymal covering of the ventricular walls, choroids plexus were founded in bouth groups. The results indicate that intraventricular administered t-PA significantly enhanced the lysis of intraventricular blood clots, but r-PA (in second group) promoted delayed periventricular white matter edema formation (more 21 days).

Presented is a review of the literature on the problem of hypoxic-ischemic perinatal brain damage in the context of alterations of astroglial regulation of neuronal energy metabolism and mechanisms of excitotoxicity. Characteristics of energy metabolism in the developing brain responsible for specificity of its damage in perinatal period, as well as cell and molecular mechanisms of disturbances of neuron-astrocyte coupling controlling regulation of neuroplasticity are discussed.

Current approaches to the diagnostics of acute stroke rely on methods of visualization that assess not only anatomical changes of the ischemic brain, but also allow to evaluate the potential effectiveness and safety of thrombolytic therapy beyond therapeutic “time window” and to study pathophysiological features of cerebral ischemia. Perfusion CT (PCT) is discussed herein as a reliable and easily available tool for acute ischemic stroke diagnostics, used as an add on to conventional CT scanning. PCT rapidly distinguishes the volume of irreversible damaged tissue and penumbra, and hence to choose optimal treatment approach and to assess its effectiveness. Technical and clinical features of PCT are reviewed, along with interpretation of PCT results in the view of pathophysiological mechanisms of cerebral ischemia, advantages and disadvantages of the technique and perspectives of its further development.

Cerebral amyloid angiopathy (CAA) is characterized by β-amyloid deposition in cortical and leptomeningeal arteries of small and medium size that disturbs normal structure of arterial wall. CAA is one of the often causes of peripheral intracerebral hemorrhages and cognitive impairment in old patients. We describe male patient, 52 years with CAA. Clinical picture was characterized by recurrent cortical-subcortical (lobar) hemorrhages, cognitive impairment of subcortiical type and epileptic seizures. MRI revealed superficial posthemorrhagic lesions. Gradient-echo MRI found small multiple asymptomatic hemorrhages in cerebral cortex and subcortical matter. Repeat gradientecho MRI carried out monthes revealed new clinically asymptomatic hemorrhages. Arterial hypertension as a cause of intracerebral hemorrhage was excluded on the base of atypical location of hemorrhage (superficial, but not deep). CAA diagnosis was made according to international Boston criteria: multiple lobar, cortical-subcortical hemorrhages not connected with other definite cause of intracerebral hemorrhage. Gradient-echo MRI is of a great importance in diagnosis of CAA, as it discovers small cortical and superficial hemorrhages, none detected by standard MRI regimes.