The effect of indomethacin on the cytokine cascade and body temperature following burn injury in rats.

This study investigates the hypothesis that indomethacin's ability to prevent "fever" following burn injury in rats is mediated via decreased plasma concentrations of IL-6, the putative mediator of increased body temperature. Sprague-Dawley rats had radio transmitters and osmotic pumps containing indomethacin placed in the peritoneal cavity. Seven days later full thickness scald burns to 50% of the body surface area were produced. Following burn injuries, daily blood samples were obtained from a carotid catheter for assay of lipopolysaccharide (LPS), interleukin-1alpha (IL-1alpha), IL-1beta, tumor necrosis factor-alpha (TNF-alpha) and IL-6. In addition, body temperature (T(B)) and activity index were obtained every five minutes by telemetry. There were four experimental groups: burn + indomethacin (B-In); burn + polyethylene glycol (Peg) (B-Peg); control + indomethacin (C-In); and control + Peg (C-Peg). Burned animals demonstrated a significant two-fold increase in plasma IL-1alpha levels (p=0.004) and a seven-fold increment in IL-6 (p=0.0001) through the 7th PBD, and indomethacin administration had no significant effect upon the cytokine plasma levels. There were no significant increases in IL-1beta, TNF-alpha or LPS in any group. Indomethacin eliminated the chronic increase in T(B) following burn injury, and this effect was not produced by changes in plasma levels of the endogenous pyrogens IL-1alpha and IL-6.     

Characterisation of a myofibroblast-like cell line from an angiosarcoma

We have isolated a cell line (ASMM) by serial passage of cells from explant cultures of an angiosarcoma resected from the calf of a 62 year old female. ASMM has been in continuous culture for over eighteen months (>150 population doublings) and has a Fibroblast-like morphology with a doubling time of approximately 72 h. ASMM has a normal diploid karyology and is unable to generate tumors in nude mice or produce colonies in soft agar. Examination of the cytoskeletal proteins shows both desmin and vimentin and a low level of alpha-smooth muscle actin, which can be upregulated by treatment with TGF beta. Low levels of basal VCAM-1 are significantly upregulated with TNF alpha and reduced by the presence of TCF beta. Basal ICAM-1 is also upregulated with TNF alpha and we show an additional upregulation through TGF beta. ASMM expresses high levels of the hyaluronate receptor CD44, including the variant exons 6, 8 and 10. In addition, ASMM synthesises high levels of hyaluronate (HA), as did the original tumor. Unlike human umbilical vein endothelial cells (HUVECs) these cells were unable to generate capillary-like tubes when seeded onto basement membrane gels, and generated cords of cells containing many synthetic organelles and intermediate filaments. We were unable to detect the expression of factor VIII-related antigen, von Willebrand factor (vWF), CD31 or CD34, and were not able to induce expression of E-selectin after TNF alpha stimulation. In conclusion, this cell line represents a partially transformed population of cells which show characteristics consistent with myofibroblast-like cells. The production of high levels of HA and expression of CD44 may help to explain the high degree of agressiveness of the tumor from which ASMM was derived, as these molecules have been shown to play a role in cell motility and adhesion.     

Breast tumor-derived factors stimulate reduction of estrone to estradiol in nonmalignant breast tissue

Summary This study examines the paracrine influence by human breast carcinoma cells (UISO-BCA-1) on nonmalignant breast tissuein vitro. The 17-OH-SDH-mediated reductive pathway (estroneestradiol) was significantly increased in nonmalignant breast tissue coincubated with human breast carcinoma cells, compared to control tissues incubated in the media alone. No influence on the enzyme activity was noticed in coincubated breast cancer cells. Preincubation of breast cancer cells with estradiol (10^–8 M) significantly decreased the enzyme activity in coincubated nonmalignant breast tissue, which was restored to control levels by addition of R5020 (10^–8 M), tamoxifen (10^–6 M), or a combination of both. In nonmalignant tissues incubated in the presence of growth factor TGF, enzyme activity was reduced to between 46% and 76%. No other growth factors (IGF I, IGF II, PDGF) influenced enzyme activity. In nonmalignant tissues incubated with malignant tumor cytosol, enzyme activity was increased in 16% cases, inhibited in 21%, and not significantly changed in 63%.The data from the present study suggest that factors produced by breast carcinoma cells may influence interconversion of estradiol in nonmalignant tissue. In patients, factors produced by malignant tumor mass may have paracrine influence on surrounding nonmalignant breast tissue and, thereby, may influence the estrogen availability to tumor mass.     

Bergmann's rule near the equator: latitudinal clines in body size of an Andean passerine bird

Critical correlative support for Bergmann's ecogeographic rule is provided by symmetrical patterns of size variation in Diglossa carbonaria, a tropical passerine bird whose geographic range in the Andes Mountains of South America straddles the equator. Body size is positively correlated with latitude both north and south of the equator. Moreover, parapatric taxa that exhibit either partial (north-western Bolivia) or complete (northern Peru) reproductive isolation converge in body size. Relative uniformity in the length of the highly modified flower-piercing bill among populations of D. carbonaria that differ significantly in body size suggests that character displacement or interspecific competition is not responsible for these patterns. These findings support the hypothesis that climate, particularly temperature seasonality, is an important environmental determinant of geographic size variation in homeotherms. In addition they demonstrate that clinal variation correlated with subtle climatic gradients can occur in tropical environments.     

Multigenic control of skin tumor susceptibility in SENCARA/Pt mice

Skin tumors induced in mice by initiation-promotion (2 microg DMBA-2 microg TPA) protocols were found to be under multigenic control. Eighty- one N2 mice from the cross (BALB/cAnPt x SENCARA/Pt)F1 x SENCARA/Pt that were either solidly resistant (no papillomas) or highly susceptible (> or = 7 papillomas/mouse) were subjected to a 'genome scan' using 89 microsatellite markers to check for associations with susceptible and resistant phenotypes. A locus on Chr 5 (Skts4) was found to control the susceptibility of SENCARA/Pt mice and the resistance of BALB/cAnPt mice to papilloma formation. In addition, higher than expected linkage scores were seen for the markers D9Mit271, D11Mit268 and D12Mit56. Further work is required to establish whether genes determining papilloma formation are located in these regions of the genome. In general, no evidence was seen for loss of heterozygosity in microsatellite markers on Chrs 5, 9 and 11 in 17 microdissected papillomas from (BALB/c x SENCARA)F1 hybrid mice.      

Development of a new metastatic human breast carcinoma xenograft line.

Xenografts originated from human tumours offer the most appropriate research material for in vivo experimental research. However, primary human breast carcinomas are difficult to grow when transplanted in athymic mice: tumour take is less than 15%. Recently, we have achieved 60% tumour take by injecting tumour cell suspensions mixed with Matrigel. Human breast xenografts originated from primary breast carcinoma also frequently show the potential to metastasize spontaneously. In the present study, we generated a human breast carcinoma xenograft line (UISO-BCA-NMT-18) that shows 100% tumorigenicity and 80-100% lung metastasis when transplanted s.c. in athymic mice. We have studied in detail the characteristics of the xenograft and the patient''s tumour from which the xenograft line originated. Both the xenograft and the patient''s tumour showed intense staining for mutant p53 nuclear protein, and high expression of U-PA, PAI and u-PAR. In vivo growth of the xenograft is stimulated by exogenous supplementation of oestrogen. This xenograft is continuously growing in mice and has shown 80-100% metastasis for the last three successive in vivo passages. This well-characterized, oestrogen-responsive, metastatic breast carcinoma xenograft line will provide excellent research material for metastasis-related research.