No abstract

A new poly(L-)lactic acid (PLLA) thread was tested by applying it in fascial closures of male Wistar rats. The tissue reactions around the thread and in the fascial union, and the changes on the surface and the mechanical properties of the thread were evaluated at 1, 3, 6, 12, 28, and 52 weeks following surgery. Histologically, the extension of the general inflammatory reaction and the number of the different cell types did not markedly change during the 52-week follow-up period. The surface of the thread was intact up to 28 weeks when examined with the scanning electron microscope. At 52 weeks no thread was found. The breaking force and the stretching of the incubated PLLA thread was reduced about 20% during the first 2 weeks and it remained constant up to 6 weeks. The in vivo testing of the fascial strips closed with the PLLA thread retained their resistance against the breaking force, nearly comparable to that of the intact control fascial strips. It can be concluded that the PLLA thread is a suitable suture for wounds that require healing time of up to 28 weeks and thus need good support from the suture.

The occurrence of large-bowel melanosis was evaluated by microscopy in 200 large bowels at autopsy. Melanin was seen as yellow-brown pigment in the macrophages of the lamina propria. The pigment stained with diastase-alcian blue PAS, Fontana, and iron stains. One hundred nineteen of 200 (59.5 percent) bowels showed melanosis, which was equally common in both sexes. Usually more than one segment was involved (most commonly, four segments). Melanosis was common in the proximal part of the colon, but much rarer in distal parts (sigmoid and rectum). Affected segments were successive; negative segments between positive ones were exceptional. If the rectum was affected, all five proximal segments were affected in 11 of 12 cases. The intensity of melanosis was directly related to the number of segments involved. In the oral part of the colon, affected males had a higher intensity of melanosis than affected women, but about the same intensity in the sigmoid and rectum. The fraction of patients with melanosis increased with age. Of men and women in the age group of 20 to 54 years, 32 and 44 percent were affected, and above the age of 75 years, 76 and 67 percent, respectively.