Controversy regarding the origin of characteristic stromal cells (SC) is responsible for the placement of hemangioblastoma as a single entity in the category of "tumors of uncertain histogenesis" in the current WHO classification of brain tumors. This subclassification of hemangioblastoma is, to a large extent, a consequence of a remarkable antigenic heterogeneity of SC demonstrated in many, often contradictory immunohistochemical studies. In contrast, most of the electron microscopic studies demonstrated a number of features indicating angiogenic nature of SC and, therefore, hemangioblastoma. This study reevaluated the histogenesis of SC, applying immunohistochemistry as well as electron microscopy and immunoelectron microscopy. Immunohistochemical studies confirmed most of the previous results indicating a very frequent expression of vimentin, S-100 protein, neuron-specific enolase, and cytokeratins. SC were less commonly immunoreactive for desmin, factor XIIIa, and Ricinus communis lectin receptors, and only occasionally for factor VIII and Ulex europeus lectin. They were negative for other markers of endothelial, neuronal, glial, neuroendocrine, and smooth muscle differentiation. Approximately 1% of SC showed Ki67 immunoreactivity, indicating their slight proliferative activity, consistent with the benign nature of the tumor. In contrast to the inconclusive results of the immunohistochemistry, electron microscopy demonstrated a clear relationship of SC to endothelial cells, smooth muscle cells, and pericytes. Occasional SC were found within the vascular lumina. SC often showed intracellular caveolae consistent with the formation of early capillary lumina. Moreover, occasional SC contained small Weibel-Palade bodies positive for factor VIII in immunoelectron microscopy. SC represent a heterogeneous population of abnormally differentiating mesenchymal cells of angiogenic lineage, with some morphological features of endothelium, pericytes, and smooth muscle cells. Occurrence of SC in hemangioblastoma could be related to a limited ability of angioformative stromal cells to develop an architecture of capillary lumina integrated with the vascular network of the tumor. Hemangioblastoma should be reclassified and included together with other vascular tumors of the central nervous system.

Biomarkers, Tumor↗

PubMedDate not supplied

[Organization and results of studies on acute hepatic porphyrias in Poland].

The organization, activities and experience of Porphyria Reference Centre of the Institute of Hematology in Poland is shown. A total of 214 families with acute hepatic porphyria were collected. The family studies in search of latent cases were conducted, and measures for preventing the disease attacks were taken. The therapy of the attacks consisted in glucose and heme arginate infusions, and hyperalimentation in the patients is stressed. The incidence rate of porphyrias in Poland, according to the material collected at the Institute of Hematology is 1:15,000 inhabitants, however, it is suggested that the true value is much higher.

Acute Disease↗

PubMedDate not supplied

Heme arginate (Normosang) in the treatment of attacks of acute hepatic porphyrias.

The treatment with heme arginate of 47 attacks of acute hepatic porphyrias are presented. Distribution of patients into three groups of severity has shown that the best clinical response is obtained when the treatment starts in the first three weeks from the beginning of the symptoms and in patients without deep involvement of the nervous system. The decrease in elimination of the precursors of heme was about 60% (mean) in comparison to the preinfusion values, non corresponding firmly with the clinical improvement.

Acute Disease↗

PubMedDate not supplied

[A decrease in plasma sodium ion during the course of an acute attack of porphyria].

Sodium ion level disorders were analysed in 53 patients with porphyria during 84 acute attacks of the disease. Thirty two daily water-electrolyte balances in 6 patients treated at ICU were analysed in detail. A decrease in sodium ion levels in patients with porphyria is rather rare and most frequently transient during the acute attack of the disease. Noted disorders were not characteristic for the reported syndrome of the abnormal antidiuretic hormone release. The treatment of the acute attack of porphyria requires the achievement of the positive energy balance which leads to the normalization of sodium ion levels despite intensive hydratation of some patients.

Acute Disease↗

PubMedDate not supplied