Layer-specific activity of tissue non-specific alkaline phosphatase in the human neocortex.

The ectoenzyme tissue non-specific alkaline phosphatase (TNAP) is mostly known for its role in bone mineralization. However, in the severe form of hypophosphatasia, TNAP deficiency also results in epileptic seizures, suggesting a role of this enzyme in brain functions. Accordingly, TNAP activity was shown in the neuropil of the cerebral cortex in diverse mammalian species. However in spite of its clinical significance, the neuronal localization of TNAP has not been investigated in the human brain. By using enzyme histochemistry, we found an unprecedented pattern of TNAP activity appearing as an uninterrupted layer across diverse occipital-, frontal- and temporal lobe areas of the human cerebral cortex. This marked TNAP-active band was localized infragranulary in layer 5 as defined by quantitative comparisons on parallel sections stained by various techniques to reveal the laminar pattern. On the contrary, TNAP activity was localized in layer 4 of the primary visual and somatosensory cortices, which is consistent with earlier observations on other species. This result suggests that the expression of TNAP in the thalamo-recipient granular layer is an evolutionary conserved feature of the sensory cortex. The observations of the present study also suggest that diverse neurocognitive functions share a common cerebral cortical mechanism depending on TNAP activity in layer 5. In summary, the present data point on the distinctive role of layer 5 in cortical computation and neurological disorders caused by TNAP dysfunctions in the human brain.

1H-MRS experiences after bilateral DBS of the STN in Parkinson's disease.

UNLABELLED: The objective of this study was to evaluate the changes in the concentrations of certain brain metabolites in 13 patients with Parkinson's disease before and after bilateral subthalamic nucleus (STN DBS). The N-acetylaspartate (NAA)/choline (Chol), NAA/creatine (Cr), Chol/Cr ratios were determined by single voxel Proton magnetic resonance spectroscopy ((1)H-MRS) studies on 1.0T unit using short TE stimulated echo acquisition mode (STEAM) sequence. Spectra were obtained from the right and left globus pallidus, and left fronto-basal cortex. The patients were also assessed according to the UPDRS part III, in the "medication-on and off" conditions. CONCLUSIONS: after STN DBS cortical NAA/Cho, NAA/Cr ratios increased significantly, which were highly correlated with the significant improvements of the UPDRS scores.

Ablative stereotactic surgery improves manual performance time in Parkinson's disease.

The objective of this study was to determine the influence of stereotactic ablative surgical interventions on the time required for the performance of manual tasks (i.e. performance time) in patients with Parkinson's disease (PD). We studied 28 patients after pallidotomy and pallido-thalamotomy who were evaluated at four time: before the operation, and 2 days, 3 and 6 months postoperatively. The speed of performance of handwriting and drawing were assessed by means of a chronometer using certain parts of an international standard scale (modified by Fahn). The patients were also assessed according to the Unified Parkinson's Disease Rating Scale (UPDRS) part III. The patients were divided into two groups. Those in group A had relief of all main Parkinsonian symptoms after pallidotomy including tremor. The patients in group B had no relief of tremor straight after pallidotomy. For them the pallidotomy was completed with thalamotomy in the same sitting, which had resulted in cessation of tremor. The time of performance of the manual tasks diminished significantly in all cases in both groups (Student's t-test: p<0.0001). No complications developed following pallidotomy. Pallido-thalamotomy caused transient adverse effects in two patients, and one patient developed permanent adverse effects such as dysarthria and dysequilibrium. Significant improvements were observed in the speed of handwriting and drawing in both groups, but pallido-thalamotomy was accompanied with complications.

[MRI guided stereotactic thalamotomy for the treatment of the neurogenic pain]. / Talamotomía estereotáxica por resonancia magnética para el tratamiento del dolor neural.

INTRODUCTION: Medial thalamotomy is one of the first stereotactic operations to have been used for neurogenic pain, has a low complication rate and no risk of the development of iatrogenic neurogenic pain. It represents selective local relief for all types of pain, without causing somatosensorial deficit. PATIENTS AND METHODS: We did 39 posteromedial thalamotomies in patients with persistent intractable pain due to various disorders. The pain was assessed pre- and postoperatively on the VAS (Visual Analogic Scale). RESULTS: Half of the patients operated on had relief of pain after thalamotomy. In 84% (n = 39) of our cases this relief occurred on the second day, in 70% (n = 35) after three months, in 63% (n = 27) after six months, in 64% (n = 25) after nine months, in 62% (n = 23) of the patients after 12 months, and in 62% (n = 22) after 24 months. Three patients had temporary complications and one a permanent complication, but this did not make him an invalid. CONCLUSION: Posteromedial stereotactic thalamotomy under MR guidance can provide safe, effective treatment for persistent, intractable pain.

Peptidergic innervation of human cerebral blood vessels and saccular aneurysms.

Peptidergic innervation of the human cerebral vasculature has not yet been described in detail and its role in the maintenance of cerebral autoregulation still needs to be established. Similarly, few data exist on the innervation of vascular malformations. The aim of this study was to clarify the peptidergic innervation patterns of human cerebral arteries of various sizes, and, for the first time, that of saccular aneurysms. Light microscopic study of whole-mount preparations of human cerebral arteries and aneurysm sacs resected either during tumor removal or after neck-clipping were carried out by means of silver-intensified light microscopic immunocytochemistry visualizing neuropeptide-Y, calcitonin gene-related peptide and substance P immunoreactivity. Systematic morphological investigations confirmed the presence of longitudinal fiber bundles on the adventitia and a network-like deeper peptidergic system at the adventitia-media border, while in smaller pial and intraparenchymal vessels, only sparse longitudinal immunopositive axons could be detected. The innervation pattern was totally absent in the wall of saccular aneurysms with the complete disappearance of peptidergic nerve fibers in some areas. To the best of our knowledge neither the disappearance of this network on small pial and intraparenchymal vessels, nor the absence of an innervation pattern in saccular aneurysms have been described before. Nonhomogeneous peptidergic innervation of the human cerebral vascular tree might be one of the factors responsible for the distinct autoregulatory properties of the capacitance and resistance vessels. Malfunction of this vasoregulatory system might lead to the impairment of autoregulation during pathological conditions such as subarachnoid hemorrhage.

Atrial natriuretic peptide (ANP) attenuates brain oedema accompanying experimental subarachnoid haemorrhage.

The effects of centrally administered atrial natriuretic peptide (ANP) on the brain water and electrolyte contents were investigated in a rodent subarachnoid haemorrhage (SAH) model. SAH caused statistically significant increases in the brain sodium and water contents, while the potassium content did not change significantly, indicating that the brain oedema could be classified as having a primarily vasogenic component. Two micrograms or 5 micrograms of rat ANP administered into the lateral ventricle at the time of SAH induction statistically significantly decreased the water and sodium accumulation measured 90 minutes following SAH. The same treatment did not inhibit development of brain oedema measured 3 hours following SAH. However, when 5 micrograms of ANP was administered intraventricularly at the time of SAH induction and also 90 minutes later, the brain oedema 3 hours following SAH was again reduced statistically significantly. These effects of ANP were found not to be mediated by primary changes in serum osmolality and electrolyte concentrations. The present results confirm that centrally administered ANP may act directly on the central nervous system to inhibit brain water and sodium accumulation in SAH-induced brain oedema. The potentials of influencing the central neuro-endocrine system as a novel way of the treatment of brain oedema are discussed.