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Experiments were performed to elucidate a possible mechanism for the peripheral circulatory disturbance caused by vibration. Rats were exposed to local vibration (60 Hz, 5 G) on their hind legs for four hours a day for 30 days or 90 days. With exposure for 30 days the small arteries at the exposed site did not change. With exposure for 90 days, however, disruption of the internal elastic lamina was observed in the small arteries. This disruption was followed by focal cell proliferation with regenerative formation of collagen and elastic fibres. The fibrocellular thickening of the intima was further augmented, and in addition a complete stenosis of the lumen of the small arteries was observed. Electron micrography showed that the fibrocellular thickening of the intima consisted of a proliferation of arterial smooth muscle cells and numerous collagen and elastic fibres. These alterations were not observed in the arteries of the controls. The thickness of the media did not differ between the control and exposed groups or in animals with different durations of exposure. Concerning plasma total cholesterol, HDL-cholesterol, and lipoperoxide, there were no significant differences between the control and exposed groups after either 30 or 90 days, but the whole blood viscosity was significantly increased by day 90. This finding may be related to the intimal thickening.

A new surgical approach to apical segment lung diseases, including carcinomas and inflammatory diseases A new surgical approach to lung cancer and inflammatory pulmonary diseases has been developed. This approach focuses on diseases located in the apical segments of the lung and showing invasion or severe adhesion to the apical thoracic waD or to vital organs near the thoracic dome (including superior sulcus tumors). The conventional posterolateral approach leaves the surgeon "blind" because it forces the surgeon to perform the operation looking up through a tube from the bottom. This limited view makes accurate assessment of the surrounding vital organs involved in these diseases almost impossible and also increases the risk of injury to adjacent vital organs. The incision in this new approach allows extensive retraction of the scapula to provide easier access to the posterior chest waD. Because the incision curves upward anteriorly, rather than downward as usual, it gives excellent exposure of the apical anterior thoracic region. In the few cases in which we have used this approach, we have found that the surgical field is in plain view and that the operation is consequently safer and easier. So far we have not encountered any complications, and we can recommend this approach with confidence. (J

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OKADA A, INABA R, FURUNO T, NOH ARA S, ARIIZUMI M. Usefulne ss of blood parameters, especially viscosity, for the diagnosis and elucidation of pathogenic mechanism s of the hand-arm vibration syndrome. Scand J Work En viron Health 13 (1987) 358-362. In the present study it was found that, in vibratin g-tool operators with Raynaud ' s phenomenon , whole blood viscosity was significantly higher than in operators without Raynaud 's phen omenon at shear rat es from 230 to 11.5 S-I . In addi tion rats were experimentally exposed to local vibrat ion (60 Hz, 5 g) on their hind limbs for 4 hid for 30 or 90 d. In the case of 30-d exposure, the small arteries in the exposed site did not change. However, aft er exposure for 90 d, disru ption of the intern al elastic lamina was observed in the small arter ies. The disrupti on was followed by focal cell prolifera tion with regenerati ve form ation of collagen and elastic fibers. The fibrocellular thickening of the intima was furth er augmented, and , in addition, a complete stenosis of the small lumen of the small art ery was observed. Medial thickness did not show signi ficant differences between the control and exposed groups for either exposure duration . The whole blood viscosity was significantly increased by the 90-d but not by the 30-d exposure. Th ese results suggest that there are some relationships between the increase in whole blood viscosity and the intimal thickening of some small arteri es in the exposed site.