Role of tumor-derived fibroblasts in the growth of primary cultures of human breast-cancer cells: Effects of epidermal growth factor and the somatostatin analogue octreotide

In the present study we have investigated the role of human breast-cancer-derived fibroblasts in the proliferation of primary cultures of epithelial cells derived from the same tumor. For this purpose, a co-culture system, using Transwell tissue-culture inserts with microporous membranes was employed. Fibroblasts and epithelial cells were enriched according to differences in their density on Percoll density gradients. The co-culture system was first established using MCF-7 breast cancer cells and a human fibroblast line (HF cells). Insulin, 17β-estradiol, EGF and HF cells all significantly stimulated the growth of MCF-7 breast cancer cells. The stimulatory effects of insulin, E2 and EGF were additive to the stimulatory effect of HF cells. These data suggest that (unique) factor(s), other than the above-mentioned growth-promoting compounds, are responsible for the growth-promoting effects of fibroblasts. In half of the human breast cancers investigated, tumor-derived fibroblasts stimulated tumor-derived epithelial cell proliferation. EGF significantly stimulated epithelial cell proliferation in 4 out of 6 cultures. The stimulatory effects of fibroblasts and EGF were additive or synergistic, and were observed in the additional presence of FCS, again suggesting production of unique factor(s) by the fibroblasts, in one culture the fibroblasts significantly inhibited epithelial tumor-cell proliferation. Conversely, the epithelial cells significantly stimulated proliferation of fibroblasts in 3 out of 3 cultures. The somatostatin analogue octreotide significantly inhibited epithelial cell proliferation by 46% in one tumor-cell culture in the absence, but not in the presence, of fibroblasts. In one culture, octreotide significantly inhibited the proliferation of fibroblasts co-cultured with epithelial cells

Role of cholecystokinin in dietary fat-promoted azaserine-induced pancreatic carcinogenesis in rats.

The role of cholecystokinin in dietary fat-promoted pancreatic carcinogenesis was investigated in azaserine-treated rats, using lorglumide, a highly specific cholecystokinin-receptor antagonist. The animals were killed 8 months after the start of treatment. Cholecystokinin, but not dietary unsaturated fat, increased pancreatic weight. Rats treated with cholecystokinin developed more acidophilic atypical acinar cell nodules, adenomas and adenocarcinomas than control animals. Rats maintained on the high-fat diet developed significantly more adenomas and adenocarcinomas than controls given a diet low in unsaturated fat. Lorglumide largely inhibited the enhancing effect of cholecystokinin, but not of dietary fat, on pancreatic carcinogenesis indicating that it is unlikely that the promoting effect of dietary unsaturated fat on pancreatic carcinogenesis is mediated via cholecystokinin

Prevalence of colonisation with group B Streptococci in pregnant women of a multi-ethnic population in the Netherlands

Objective: This study was performed to determine the prevalence of GBS and to identify GBS colonisation risk factors in a multicultural population of pregnant women in The Netherlands. We calculated predictive values of cultures in pregnancy for intrapartum GBS carriage. Study design: From a total of 1702 women visiting several antenatal outpatient departments, rectovaginal swabs were collected at 35-37 weeks' gestation. In 761 women swabs were repeated at time of delivery. Carriage of GBS late in third trimester and at time of delivery was analysed in relation to age, parity, ethnicity and socio-economic status. Results: Twenty-one percent was GBS carrier late in pregnancy. Compared to Europeans, African women were at a higher risk (29%, RR 1.4, CI 1.1-1.7) and Asian women were at lower risk (13%, RR 0.6, CI 0.4-0.8) for GBS carriage. No differences in colonisation were found between women with respect to age, parity or socio-economic background. Positive predictive value of GBS carriage at 35-37 weeks' gestation for carriage at time of parturition was 79% and negative predictive value was 93%. Conclusions: It was not possible to identify a group of pregnant women at high risk for GBS colonisation. Predictive values of antenatal genital group B streptococci cultures at 35-37 weeks' gestation for intrapartum GBS carriage are lower than previously reported