Summary To determine whether tumour growth is influenced by circadian variations in tumour tissue blood flow, we measured changes in area doubling time of tumours (Sato lung carcinoma) within transparent chambers and changes in tissue blood flow of rat subcutaneous tumour during a light-dark cycle. Rats were subjected to an artificial light-dark cycle with light from 7 a.m. to 7 p.m. Tumour doubling times (TDTs) dunrng the dark and the light spans were 33.5 ± 11.9 h (n = 38, 20 rats) and 70.6 ± 36.9 h (n = 39, 20 rats) respectively. The former was significantly shorter than the latter (P<0.001). In addition, the larger the tumour became, the longer was the TDT during the light span (P<0.05). Tumour tissue blood flow dunrng the night (10 p.m.-4 a.m.) was approximately 1.5 times greater than that during the day (10 a.m.-4 p.m.). The time dunrng which tumours actively grow and that during which tissue blood flow in tumours increases coincided. These results strongly suggest that tumour tissue blood flow is a determining influence on tumour proliferative activity and that tumour growth is influenced by circadian variations in tumour tissue blood flow.
To determine the phenotypic expression of cementoblasts responsible for acellular cementum, an immunohistochemical study was performed using a polyclonal antibody raised against the aminoterminal peptide of rat osteocalcin (OC). Maxillary first molars of Wistar male rats aged 2 and 3 wk were used for observations. Serial sections of decalcified paraffin embedded specimens were stained either with hematoxylin and eosin or with the anti-OC antibody. In 2-wk-old rats, apical roots were lined with the epithelial root sheath. A thin layer of acellular cementum was seen at most of the root surface, but was not seen near to root apex. In 3-wk-old rats, cellular cementum began to be formed at root apex, and acellular cementum became more thick than in 2-wk-old rats. Acellular and cellular cementum were lined with the fibroblast-like cells. Osteocalcin staining was detected in cells lining root surface in both 2- and 3-wk-old rats. Almost all cells lining cellular cementum were positive for OC. In contrast OC positive cells lining acellular cementum and root surface devoid of cementum appeared at a specific site of the root. The cells at the interradicular area of root surface were positive but the cells at the outer area (the opposite side of the interradicular area) were negative for OC. Osteoblasts and odontoblasts were positive with the antibody. The present results suggest that the OC expression of cementoblasts forming acellular cementum is similar to that of cells forming cellular cementum as well as osteoblasts and odontoblasts, and has a role for calcification of acellular cementum.
Summary Using the rat tumour cell line LY80, a subline of Yoshida sarcoma, the effects of AGM-1 470 on the growth of primary tumour and the incidence of regional lymph node metastasis were evaluated. AGM-1 470 (30 mg kg-') was administered subcutaneously or intravenously. Subcutaneous (s.c.) and intravenous (i.v.) injections were repeated for 8 days and 7 days respectively. Tumour growth of a primary region tended to be suppressed by AGM-1470. The s.c. tumours after sacrifice were much smaller in the AGM-1470-treated group (s.c. injection) than in the control groups. However, the growth of metastatic foci in the lymph nodes was prompted markedly by AGM-1470. All six of the AGM-1 470-treated rats had developed swollen axillary lymph nodes and/or brachial lymph nodes on day 19 after tumour implantation (the 7th day after the last treatment) compared with one of six saline-injected rats and three of six vehicle-alone treated rats with swollen axillary lymph nodes. The weight of lymph nodes after sacrifice in the AGM-1470-treated rats was much heavier than that of the other two groups.Histological examination showed that in the AGM-1470-treated group, the cortex and the medulla of the axillary lymph nodes were almost entirely replaced by tumour cells while, in the vehicle alone group, a notable hyperplasia of the lymph nodes due to BT cell proliferation tended to be induced. In the saline group, although a slight hyperplasia of lymph nodes was observed, there were only a few lymph node metastases. In the case of i.v. injection of AGM-1470, similar results were obtained. It is thought that LY80 cells spread to regional lymph nodes at a comparatively early stage by some change or other in which AGM-1470 participated. From the present experiment, it is concluded that application of AGM-1470 alone to patients should be carried out with great caution.Keywords: angiogenesis; AGM-1470; LY80 cell; lymph node metastasis It has been reported that AGM-1470, an analogue of fumagillin isolated from Aspergillus fumigatus, inhibited tumour growth in mice and rats (Ingber et al, 1990;Yamaoka et al, 1993a;Yanase et al, 1993) and extended the survival time of animals with some kinds of tumours (Yamaoka et al, 1993b). Furthermore, in mice treated with AGM-1470, haematogenous metastasis was strongly inhibited with regard to both the number and the size of tumour nodules (Yamaoka et al, 1993b;Tanaka et al, 1995). To date, however, there have been very few studies on the effects of AGM-1470 on lymphogenous metastasis. To improve the chance of survival, it is important to inhibit not only haematogenous metastasis but also lymphogenous metastasis, because metastases to the regional lymph nodes occur very frequently in cancer patients.The purpose of the present study was to evaluate the effects of AGM-1470 on both the growth of primary s.c. tumours and the incidence of regional lymph node metastasis. Using a model of lymph node metastasis, we used the LY80 tumour cell line system, in which tumour cells spontaneously and uniformly metastasi...
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