After laser irradations, retinas of 13 rabbits were examined by electron microscope. The laser focus was set between 30 min and 140 h or 6 weeks in advance. The anatomical separation between the retina and the connective tissue of the choriocapillary in all the lesions is preserved by an intact Bruch's membrane. Destruction of the pigment epithelium, rod layer, and outer granular layer occurs in the early stages after coagulation. Later the nuclei of the rods show various stages of degeneration with simultaneous increases in the volume of the Müller's cells. The cytoplasma of the Müller's cells penetrates the nuclei of the sensory cells undergoing degeneration. Proliferation of the pigment epithelium begins after about 20 h. The first appearance of macrophages in the retina is visible after 30 h. Between 92 and 140 h in the area of the pigment epithelium, variously differentiated cells, which partly contain pigment granules and lamellary inclusion bodies, form. Some cells or cell groups which are visible might represent histiocytes within the Bruch's membrane 35, 45, 68, and 92 h as well as 6 weeks after coagulation. They partly cross the outer layer of the Bruch's membrane and neighboring connective tissue of the choroid. According to our studies, pigment epithelial cells, choroidal histiocytes, and Müller's cells participate in the phagocytosis.

Prä-und intraoperative Befunde von 71 Patienten mit rhinochirurgisch verschlossener frontobasaler Liquorfistel werden gegenubergestellt. In 80% der

The electron microscopical findings in the outer nuclear layer of the rabbit retina following exposure of ruby laser beams are described: half-an-hour following laser coagulation the nuclei show a conglomeration of the chromatin. 20 h after coagulation, fragments of outer and inner segments of the rods are observed in the outer nuclear layer. Some cells also contain homogeneous and dense nuclear aggregations of small electrondense granules. 25 h after laser application, the alterations in the nuclei are more pronounced : the chromatin shows a marginal condensation or has sickle-shaped appearance. 35 h after coagulation, Müller cells appear in the outer nuclear layer. 10 h later these cells accumulate, whereas the outer nuclear cells decrease. Between 45 and 116 h, macrophages and Müller cells are observed in the outer nuclear layer.

The value of biochemical methods, scintigraphy and sonography in the diagnosis of liver metastases was compared in 150 patients. Of the laboratory methods, gamma-GT proved the most suitable screening method. A negative scan was of considerable value in excluding liver metastases. Positive findings are not always definite and require confirmation. Ultrasound, because of its high accuracy, is the most valuable method for excluding or demonstrating liver metastases. Suggestions for diagnostic procedures are made as a result of these findings.

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