Muscle fibers of the masseter muscle of mice which had been fed a fine-grained diet for various periods were studied histochemically and morphometrically. The diameters of both extrafusal and intrafusal muscle fibers decreased with time in mice fed a fine-grained diet, compared with those of control mice. In animals maintained on the special diet for 160 days after weaning at the 20th postnatal day, the effects of the diet on the diameter of muscle spindles were severe, and the diameter of each type of red and white fibers was significantly smaller than those of control animals. But a significant difference was not recognized in the diameter of intermediate fibers between control and treated mice. Unexpectedly, white fibers having a smaller diameter than red fibers were observed in diet-fed mice after the 180th postnatal day, although white fibers having such small diameter were not detectable in control animals. Succinic dehydrogenase activities were decreased in both extrafusal and intrafusal fibers of experimental animals. Moreover, muscle spindles with no annulospiral endings were increased in number in mice fed the diet for 130 and 160 days after weaning, although those spindles also increased in control animals. The diameters of outer capsules and primary endings were also significantly decreased in the animals kept on the diet for a long time. These effects of the finegrained diet on the mouse masseter muscle became severer with time.
Background
Recently, colorectal cancer has increased in elderly patients worldwide, with laparoscopic colorectal surgery increasing in elderly patients with colorectal cancer. However, whether laparoscopic colorectal surgery is an optimal procedure for colorectal cancer in the elderly remains unclear. This study aimed to verify safety and curability of laparoscopic colorectal surgery in elderly patients ≥80 years old.
Methods
Patients undergoing curative colorectal surgery from 2006 to 2014 were enrolled and classified into the laparoscopic surgery in elderly patients aged ≥80 years (LAC-E) group, open surgery in elderly patients (OC-E) group, and laparoscopic surgery in non-elderly patients (LAC-NE) group. Short- and long-term outcomes were compared between these groups.
Results
The LAC-E, OC-E, and LAC-NE groups comprised 85, 25, and 358 patients, respectively. Intraoperative blood loss and incidence of postoperative complications were significantly lower in the LAC-E versus OC-E group (97 vs. 440 mL, p < .01 and 14% vs. 32%, p < .05, respectively). Long-term outcomes were not different between these two groups. Operation time was significantly shorter in the LAC-E versus LAC-NE group (249 vs. 288 min, p < .01). Intraoperative blood loss and postoperative complications were similar between the groups. Although the 5-year overall survival rate in the LAC-E group was lower than that in the LAC-NE group (64% vs. 80%, p < .01), there was no difference in 5-year disease-specific survival between the groups.
Conclusion
Laparoscopic colorectal surgery is technically and oncologically safe for colorectal cancer in the elderly as well as the non-elderly and can be an optimal procedure for colorectal cancer in the elderly.
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