Dynamic visual acuity (DVA) is defined as the ability to discriminate the fine parts of a moving object. DVA is generally better in athletes than in non-athletes, and the better DVA of athletes has been attributed to a better ability to track moving objects. In the present study, we hypothesized that the better DVA of athletes is partly derived from better perception of moving images on the retina through some kind of perceptual learning. To test this hypothesis, we quantitatively measured DVA in baseball players and non-athletes using moving Landolt rings in two conditions. In the first experiment, the participants were allowed to move their eyes (free-eye-movement conditions), whereas in the second they were required to fixate on a fixation target (fixation conditions). The athletes displayed significantly better DVA than the non-athletes in the free-eye-movement conditions. However, there was no significant difference between the groups in the fixation conditions. These results suggest that the better DVA of athletes is primarily due to an improved ability to track moving targets with their eyes, rather than to improved perception of moving images on the retina.
These results suggest that the better DVA of baseball players is primarily due to a better ability to track moving objects with their eyes rather than to improved perception of moving images on the retina. This skill is probably obtained through baseball training.
Hemolymphangioma of the pancreas is a very rare benign tumor. There were only five reports of this disease until March 2008. Herein, we report a case of hemolymphangioma of the pancreas with gastrointestinal bleeding due to duodenal invasion. A 53-year-old man had been admitted a referral hospital because of severe anemia due to gastrointestinal bleeding in December 2005. He was then transferred to our institute with a diagnosis of a tumor of the head of the pancreas with duodenal invasion in January 2006. No abnormalities were revealed except for anemia in laboratory data including CEA and CA19-9. Gastrointestinal endoscopy r e ve a l e d b l e e d i n g a t t h e d u o d e n u m . C o m p u t e d tomography also demonstrated a heterogenous mass at the pancreatic head and suspected invasion to the duodenal wall. Ultrasonography showed a huge mass at the pancreatic head with a mixture of high and low echoic areas. Pylorous-preserving pancreatoduodenectomy was performed. The pancreatic tumor was soft and had invaded to the duodenum. The pathological diagnosis was a hemolymphangioma of the pancreas invaded to the duodenum. His postoperative course was uneventful and he was discharged on the 26th d after surgery. Hemolymphangioma of the pancreas is a very rare benign tumor. In a literature review until March 2008, we found five case reports. Major symptoms are abdominal pain and distension due to the enlarged tumor. However, we experienced a case of hemolymphangioma of the pancreas with gastrointestinal bleeding due to invasion to the duodenum. This disease is a very rare entity, but should be considered when patients have gastrointestinal bleeding.
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