Acute effect of the carbon dioxide laser on the epicerebral microcirculation. Experimental study by fluorescein angiography

The effect of laser radiation on the central nervous system has been studied in cases of clinical and experimental tumors. However, no report yet exists on the effects of laser radiation on the cerebral microcirculation in vivo. Cerebral fluorescein angiography permits observations of small vessels that are not possible by conventional angiography. In this study, disturbance in the epicerebral microcirculation after carbon dioxide laser radiation was localized. On fluorescein angiograms, a circular zone of nonfilling of fluorescein dye around the site of impact, 1 to 1.5 mm in diameter, was seen throughout from the arterial to later venous phase. Around the nonfilling area, thrombus formation in small vessles and extravasation of the dye were demonstrated. Such extravasation of the fluorescein remained after the dye had faded from the venules and veins. Microscopically, coagulation necrosis was observed to coincide with the area of nonfillin of fluorescein dye in the fluorescein angiograms. In areas surrounding this, edema, dilatation or rupture of the capillaries, and thrombus formation in the arterioles were observed. Such areas coincided with those of extravasation of the fluorescein dye.

Genetic analysis of incompatibility in the diploid Ipomoea species closely related to the sweet potato

In order to identify the genotypic constitutions of incompatibility in the diploid species, Ipomoea leucantha Jacq. (K221), which is most closely related to the sweet potato, the progenies derived from the reciprocal crosses, backcrosses and testcrosses were analysed. All the plants examined were self-incompatible, and pollen germination was inhibited on the stigma after incompatible pollinations. No reciprocal differences were found in the incompatibility reactions. In the progenies three incompatibility groups were observed which showed the rather simple segregation ratios. The homozygous plants for incompatibility alleles were obtained in the progenies. The experimental results demonstrated a sporophytic type of incompatibility controlled by a single locus with multiple S-alleles exhibiting a dominance relationship in both the pollen and the stigma. The plants obtained in the progenies had the following genotypes: S 1 S 2, S 1 S 3, S 2 S 2, S 2 S 3 and S 3 S 3.

[Arterial occlusion following cerebral vasospasm (author's transl)]

1. The present study analysed the clinical course, the serial angiograms and the CT scans of the patients with angiographic arterial occlusion following vasospasm after subarachnoid hemorrhage. The occlusion was observed in 6 out of 84 patients with vasospasm. 2. The angiograms which showed this phenomenon were obtained between the 11th and the 30th day of the illness. The affected vessels were the branches of middle cerebral artery. 3. Thrombus formed on the intima which had been injured by vasospasm is suspected to be a genesis of this arterial occlusion. The pathological findings of a case in this series support this concept. 4. The surgical procedure during the direct aneurysmal operation performed in the period of "smooth narrowing" seems to be a contributing factor to the arterial occlusion. There was no correlation between antifibrinolytic therapy and this phenomenon except in one case. 5. Fibrinolytic therapy after clipping of aneurysm may be a treatment of choice for this arterial occlusion following vasospasm.