Pineal gland calcification under hypoxic conditions.

The pineal gland (glandula pinealis) is neuroendocrine gland located at the epithalamus of the brain secreting melatonin. The aim of this study was to explore effects of prenatal hypoxia in rats at the age of 33 weeks on the occurrence of pineal gland calcification. Distribution and chemical composition of calcerous material by light, scanning and transmission electron microscopy was investigated. Melatonin concentrations in blood plasma by direct radioimmunoassay were measured. Rats were exposed to prenatal hypoxia for 12 h at day 20 of development and second group to prenatal hypoxia for 2x8 h at days 19 and 20 of development. Vacuoles of intracellular edema in the pineal samples after 12 h hypoxia were found. Their size ranges up to 30 µm. Some of them were filled with the flocculent and fibrous material. Samples of pineal glands after 2 x 8 h hypoxia revealed the pericellular edema of pinealocytes. The amount of calcium rich particles in 2 x 8 h hypoxia group was lower than in 12 h hypoxia group. Plasma melatonin levels did not differ between control and both hypoxia groups. We concluded that calcification is a process induced by osteoblasts and osteocytes with melatonin as a promotor and it is favored under hypoxic conditions.

The combined algorithm of venous ulcer therapy.

AIM: This prospective study was undertaken to find a new combined algorithm to help patients suffering from long-term chronic non-healing venous ulcers. METHODS: A total number of 20 patients suffering from chronic venous ulcers and important co-morbidities such as diabetes mellitus or cardiac failure and not responding to other therapeutic modalities were treated at our surgical department with a combination of compressive sclerotherapy, and maggot debridement therapy (MDT) using larvae of green blowfly Lucilia sericata. RESULTS: Using the combined therapy we have achieved a significant clinical effect in 19 patients (95 %). In 1 patient, this effect was only impermanent while 5 patients (25 %) were completely cured. Eleven patients (55 %) benefited despite incomplete healing of the ulcer. With three of our patients we have lost contact. CONCLUSIONS: Even though the number of patients in our study is not large, we have achieved remarkable results with the combined algorithm of venous ulcer therapy. We start the healing process with compressive sclerotherapy and when this kind of therapy does not bring about the expected effect, we continue with Maggot debridement therapy. This combination of therapeutic modalities appears to be very effective and efficient (Fig. 2, Ref. 16).

Merkel cells--review on developmental, functional and clinical aspects.

The objective of this review is to introduce Merkel cells, to provide a basic overview on the theoretical background of function, development and clinical importance of Merkel cells. Merkel cells (MCs) are post-mitotic neuroendocrine cutaneous cells primarily localized in the epidermal basal layer of vertebrates and concentrated in touch-sensitive areas in glabrous, hairy skin and in some mucosa. There is a great site variation in the density of MCs. In routine light microscopy human MCs can hardly be identified. Cytokeratine 20 is a reliable marker with highest degree of specifity. MCs can be also distinguished by electron microscopy. The origin of human MCs has been controversial. Some investigators believe that it is a neural crest derivate, whereas others have proposed that it is a differentiation product of the fetal epidermal keratinocytes. Most studies focus on neuroendocrine functions and their possible malignant transformation into Merkel cell carcinomas (MCC). MCC is an uncommon and often aggressive malignancy and found mainly in elderly patients. It occurs most frequently in the head and neck region. MCC may be difficult to diagnose, it appears as a firm, painless lump. Diagnosis is based on typical histology representation on haematoxylin-eosin stained slides together with the results of immunohistochemistry. Histologically, MCC has been classified into three distinct subtypes: trabecular, intermediate and small cell type. Radical surgery is the recomended procedure for the treatment of primary MCC. Oncological treatment is generally reserved for stage III. (distant metastases) cases of MCC (Tab. 1, Fig. 13, Ref. 58). Full Text in free PDF www.bmj.sk.