Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

[EX Q]: Abstract: To determine the end point of histopathologic damage in avulsed arteries, the forearm arteries of five monkeys being sacrificed were avulsed longitudinally and samples of proximal and distal arteries prepared for light microscopy and transmission and scanning electron microscopy. A severe and consistent circumferential skip lesion was found on the luminal surface involving the intima and media. In 30 percent of vessels, histopathologic damage extended more than 3.0 cm from the rupture point. Similar circumferential tears occurred on the luminal surface of resected human avulsed arteries collected at the time of replantation surgery. No consistent lesions were noted in resected veins from human avulsed amputations. It is possible that in the human artery (as in the monkey) circumferential lesions frequently extend many centimeters from the rupture point and therefore beyond resection distances. Lesions present in the vessel after resection and microsurgical repair might be the site of thrombosis and subsequent occlusion.
[EX A]: Animal

[EX Q]: Abstract: The objective of this study was to find naturally occurring anti-idiotypic (anti-Id) antibodies to anti-human thyroglobulin (anti-hTg) idiotype in sera of patients with autoimmune thyroid disease. Sera from patients with Hashimoto's thyroiditis (HT), Graves' disease (GD), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE) and sera from normal subjects were tested for the presence of anti-Id antibodies against mouse anti-hTg monoclonal antibodies (McAb) in indirect ELISA and in indirect solid-phase RIA. Microtitration plates were coated with six McAb, five of them directed against different epitopes on hTg molecule, and then incubated with patients' sera. The bound antibody was detected with either peroxidase or 125I-labeled anti-human IgG. The specific positive reaction was observed in four of 40 patients with HT, in two of 26 patients with GD, in seven of 58 patients with RA, and in none of 20 normal subjects. The detected binding was due to the presence of anti-hTg anti-Id antibodies and not to Tg-anti-Tg circulating immune complexes, as the positive sera did not contain hTg when resolved on SDS-PAGE, nor did they bind to all anti-hTg McAb tested. The binding was dose dependent, and titers of anti-Id antibodies varied from 1:243 to 1:2187. The binding could be inhibited up to 50% by hTg, but not by the thyroid microsomal antigen, indicating that some of those anti-Id might represent the internal image of the antigen. Serum from the patient 3403, showing the strongest reactivity against McAb A-3, was chosen for IgG purification and F(ab')2 fragment isolation. The 3403 F(ab')2 fragment, but not the Fc fragment, was found to react specifically with four mouse anti-hTg McAb but not with the control mouse IgG. Thus, the obtained results permit the conclusion that anti-hTg anti-Id antibodies could occur naturally during the course of thyroid autoimmune disorders.
[EX A]: Antibodies, Monoclonal

[EX Q]: Abstract: Developmental changes and sexual differences in the lactotrope population were studied with a reverse hemolytic plaque assay for detection and measurement of PRL secretion from individual cells in conjunction with PRL immunocytochemistry (ICC). Pituitary glands from both sexes at different ages were monodispersed with 0.1% trypsin. Freshly dispersed cells were incubated in Cunningham chambers for measurement of the fraction of plaque-forming cells and the size of plaques formed, or attached to glass slides for measurement of the fraction of cells staining for PRL by ICC. The percentage of plaque-forming cells in both sexes gradually increased with age from about 5% of the total anterior pituitary cell population at 5 days of age to the adult levels of about 54% in the females at proestrus and about 37% in the males. Sexual differences in the percentage of plaque-forming cells were consistently seen at 40 days of age and thereafter. The mean size of plaques in both sexes also increased with age from about 1,100 microns 2 at 5 days of age to a peak level of about 15,600 microns 2 in the females at proestrus and about 6,700 microns 2 in the males at 60 days of age; then fell to the adult levels of about 5,500 microns 2 in the females at proestrus and about 3,200 microns 2 in males. Sexual differences first appeared at 40 days of age and were estrogen-dependent. The results from ICC closely matched those from the plaque assay, except at 5 days of age and in the adult males. At 5 days, the fraction of cells staining for PRL was twice that of cells forming plaques. In adult male rats there were about 47% immunostained PRL cells but only about 39% plaque-forming cells. This difference, however, disappeared after estrogen treatment. These results demonstrate that sexual differences in the lactotrope population develop around puberty in rats and appear to be estrogen dependent.
[EX A]:
Age Factors