Elektronenmikroskopischer Nachweis der Adenosintriphosphataseaktivit�t am Amnion-, Nabelstrang-und Hautepithel beim Schaffetus

A histochemical study on the vitamin D synthesis into the epidermis

Using a suitable histochemical method vitamins D and 7-dehydrocholesterol could be shown into the epidermis of several mammal species. As the histochemical method used is able to discriminate vitamins D and 7-dehydrocholesterol from cholesterol and its esters, the sites where these vitamins were synthesized within the epidermis layers could be established. Vitamins D and 7-dehydrocholesterol were found into the epidermis in the same sites where cholesterol and its esters take place, such as: the keratinizing cell thick membrane and the stratum spinosum and stratum granulosum keratinocytes cytoplasm. Inside the keratinocyte cytoplasm vitamin D shows a granular pattern and appears weakly bound to proteins. The reactivity of such granules seems to be partially blocked as could be shown by an hydrolysis accomplished previously. After the hydrolysis reactive vitamin D was also found inside the epidermis intercellular space. The results suggest that vitamin D is synthesized into the cytoplasm of stratum spinosum and stratum granulosum keratinocytes, where it appears weakly bound to proteins. Afterwards it reaches the intercellular space, where its synthesis is accomplished and it becomes firmly protein-bound losing its histochemical reactivity. However, after a suitable hydrolysis the histochemical reactivity could be recovered. From the intercellular spaces vitamin D could take 2 fates: It was partially incorporated on the keratinizing cell thick membrane out surface and eliminated by means of the epidermis exfoliation. It was partially absorbed after passing across the basement membrane. On the other hand, the vitamin D placed inside the stratum spinosum and stratum granulosum keratinocytes cytoplasm become incorporated on the inner surface of the keratinizing cell thick membrane. The relationship between vitamin D biosynthesis and the epidermis lamellar bodies was discussed.

[Lightmicroscopical and histochemical studies on the chorionic plate of the mature human placenta (author's transl)]

The chorionic plate of the normal mature human placenta was studied by light-microscopy and enzyme-histochemistry. Thereby the following findings were obtained in the various layers: The enzyme content of the amniotic epithelium refers to a secretory activity. The question with regard to a resorbant activity remains unclarified. The cells of the amnion mesoderm chiefly show the enzymes of the intermediary metabolism. The intermediate layer consists of mesothelium cells which furthermore have also phagocytotic activity. The chorionic plate mesoderm consists of several layers with connective tissue cells of diverse stage of differentiation. In the early embryonic phase they differentiate amnionward from the primary cytotrophoblast layer and still get cellular supply from residual primary cytotrophoblastic cells up to the date of birth. The enzymes of the primary cytotrophoblast cells refer accordingly with a strong activity of G6PDH to proliferation and differentiation. One part of the X-cells embedded in the Langhans fibrinoid stria descends from this primary cytotrophoblast layer; but in part they differentiate also from the Langhans cells of the placental villi surrounded by the fibrinoid stria. According to their different descent, these cells show a varying content of enzymes. The bordering of the chorionic plate to the intervillous space is represented by a rudimentary, syncytotrophoblast layer.

Cytochemical localization of acid phosphatase and adenosine triphosphatase in some avian mechanoreceptors

Ultrastructural distribution of acid phosphatase and adenosine triphosphatase was studied in the receptor elements of HERBST and GRANDRY sensory corpuscles. Acid phosphatase activity was established in the elements of smooth and rough endoplasmic reticulum of perineural capsule cells, as well as in the secondary lysosomes of all cell types. Particular interest was paid on the activity of myelin-like dense bodies and some clear core vesicles belonging to the axoplasm of receptor nerve fibres. Adenosine triphosphatase activity was established on the membranes of receptor structures and pinocytotic vesicles. More deposits of electron dense material were localized on the axolemma of the non-myelinated portions of the receptor nerve fibres. The functional significance and importance of the both enzymes in the receptor structures was discussed.