ABSTRACT
To evaluate the cerebral blood flow in feline hydrocephalic brain, this study was designed to measure the regional cerebral blood flow(rCBF ; frontal and periventricular area) by the hydrogen clearance method and to visualize the vascular morphology such as angioarchitecture, diameter and number of vessels using microfil in different stages of the kaolininduced hydrocephalus. There have been several prior reports about intracraial vascular morphology, using various material such as colloida carbon and microcorrosion casts. But there is none about microfil in normal or hydrocephalic cats. The authors made a first cicrofil model to observe the vascular changes in experimental feline hydrocephalus in the literature. The results were as follows : 1) A reduction of rCBF was detected in the left periventricular area at 2 weeks after kaolin injection. A significant reduction of rCBF was revealed at left periventricular area at 4 weeks after kaolin injection. However, the rCBF of the left frontal cortex was significantly decreased at 4 week after kaolin injection. 2) A reduction in diameter of vessels was detected in the left periventricular area at 2 weeks after kaolin injection. The significant reduction of diameter in the left periventricular area was revealed at 4 weeks after kaolin injection. 3) The vessels of the periventricular area in the control cats were dense but loose in hydrocephalic cats. A reduction in number of vessels was found in the a periventricular area at 1 week after kaolin injection. A reduction in number of vessels was found at 2 weeks after kaolin injection also. And a significant reduction in number of vessels was found at 4 weeks after kaolin injection. 4) The number and caliber of vessels in the frontal cortex were similar between the control and hydrocephelic groups. However, cortical vessels of the control group were straight and parallel and showed the typical 'palisade pattern', whereas some of the hydrocephalic group showed distortion of the cortical vessels. In conclusion, ventricular enlargement causes displacement of primary cerebral arteries, followed by both stretching and a decrease in the caliber of the microvasculature, resulting in diminished cerebral blood flow and tissue destruction. The results suggest that vascular changes playa important role in the production of brain damage in hydrocephalus.
Subject(s)
Animals , Cats , Brain , Carbon , Cerebral Arteries , Hydrocephalus , Hydrogen , Kaolin , Microvessels , Silicone ElastomersABSTRACT
The microangioarchitecture of human thalamus was studied by the ink-gelatin injection, thick section transparency, histochemical staining and methacrylate cast under the stereoscope and scanning electron microscopy. There were some impressions of smooth muscular cells on the arteriole, precapillary arteriole, origin of capillary, larger venule, and converging region of each venula. Some circular impressions presented at the course of capillary regularly and discontinuously, which might be caused by contraction of pericytes of capillary. The microvascular anastomoses were rich and complex. Besides capillary anastomoses of different shape, there were many anastomoses occurred between two arterioles, or between several arterioles. The form of venular anastomoses was similar to arterioles. The anastomosis between arteriole and venule was observed occasionally. The relationship of characteristic of vertical branches of arterioles to thalamic hemorrhage was discussed.
ABSTRACT
In monkey submandibular gland there were two types of capillary networks, which were apparently different in calibre and architecture, i. e. the capillary networks around the acini and the capillary networks around the striated ducts. They originate from their respective precapillary arterioles stemed from intralobular terminal arterioles. Between the two types of capillary networks they are connected by both capillaries and postcapillary venules. The latter were called portal vessels. The capillary networks around the striated duct have two types of draining vessels. First, they converged to form postcapillary venules, which continued to form intralobular veins. Second, they directly continued to form the capillary networks around the intralobular ducts. The capillary networks around the intralobular ducts directly supplied blood through precapillary arteioles around the duct besides they connected respectively with the capillary networks around the acini and striated ducts through capillaries. Furthermore, a ring-shaped constriction was observed distinctly at the intralobular terminal arteriole.