Multiphase mechanics of capsule formation in tumors

The presence of a capsule around a tumor is known to be correlated with benign status, and the absence of a capsule often has negative implications for patient prognosis. A mechanical description is presented of the growth of a tumor and the resulting deformations of surrounding normal tissue. A mathematical model of the mechanics is analyzed using physical parameters measured in vivo and in vitro. The model has only three dimensionless parameters, and its results are very robust with respect to parameter variation. We show that the presence of contractility in the surrounding tissue, corresponding to a host defense, can make an existing capsule denser and constrain the tumor better, but cannot be responsible for the observed pressure gradients in encapsulated tumors. Some implications for treatment are discussed.

The IDDM13 region containing the insulin-like growth factor binding protein-5 (IGFBP5) gene on chromosome 2q33-q36 and the genetic susceptibility to rheumatoid arthritis

We considered that the constitutive over-expression by cultured rheumatoid arthritis (RA) fibroblast-lineage synoviocytes of genes like IGFBP5 could indicate new candidate susceptibility genes. IGFBP5 is located in a region where an insulin-dependent diabetes mellitus (IDDM) susceptibility locus, IDDM13 (2q33-q36), has been mapped. Previous evidence that non-MHC IDDM loci overlap RA susceptibility loci made IGFBP5 and its region an interesting candidate locus which was tested for linkage. Forty-nine sibships (2-4 affected siblings per sibship) with RA were genotyped with microsatellite markers covering an 11.2 cM interval in the IGFBP5/IDDM13 region. Both the two-point LOD scores and a 'nonparametric' allele-sharing analysis revealed no evidence for linkage (max LOD = 0.54, P = 0.5, respectively). Adjustments for the presence of 'shared-epitope' alleles did not significantly change the LOD scores. These results suggest that, despite the involvement of the 2q33-q36 chromosomal region in another organ-specific autoimmune disease, it is unlikely that this region harbors a RA susceptibility locus.

Comparison of adhesion mechanisms and surface protein expression in CD77-positive and CD77-negative Burkitt's lymphoma cells

The Burkitt lymphoma-derived Daudi cell line is often used as an in vitro model for germinal center B-cell function. Globotriaosyl ceramide (CD77), a marker for germinal center B-cells, is present on Daudi cells but is deficient in the Daudi-derived mutant VT500 cell line. Previous results showed a correlation in these cells between CD77 expression and expression of the B-cell protein CD19 and indicated that CD19/CD77 interaction is a mechanism for B-cell adhesion. Roles for CD77 in IFN-alpha-induced growth inhibition and anti-viral activity also have been described previously. Through flow cytometric analysis and adhesion assays, we investigated whether expression of CD77 was required for cell adhesion pathways induced by IFN or antibodies against additional B-cell surface molecules: CD20, CD22, CD38, CD40, CD81 and HLA-D proteins. In contrast to the pronounced homotypic adhesion induced by treatment with interferon-alpha in Daudi cells, no increase in adhesion was observed in IFN-treated VT500 cells. Of the B-cell proteins tested, only CD22-mediated adhesion and surface expression was stronger in Daudi than in VT500 cells. These results indicate that CD77 may be required for IFN and CD22-associated adhesion pathways, but CD77 is not a universal component of adhesion pathways in these cells.

Evaluation of skin sensitization potential of melatonin and nimesulide by murine local lymph node assay

Melatonin is a good candidate for transdermal delivery considering its short plasma half life, low molecular weight and a favorable octanol:water partition coefficient. Nimesulide is a nonsteroidal anti-inflammatory agent used orally and rectally for inflammatory disorders. The objective of this study was to investigate the skin sensitization potential of melatonin and nimesulide using the standard murine local lymph node assay (LLNA). Melatonin (0.5, 2.5, 5.0 and 10.0%, w/v) and nimesulide (0.5, 2.5, 5.0 and 10.0%, w/v) dissolved in acetone:olive oil (4:1, AOO) was applied (25 microl) on the dorsal surface of each ear of female CBA/Ca mice for three consecutive days. On the sixth day, [3H]methyl thymidine was administered intravenously and the uptake of [3H]methyl thymidine (dpm) by the draining lymph nodes was determined by established methods. Dinitrochlorobenzene (DNCB, 0.25%, w/v) and para-aminobenzoic acid (PABA, 2.5%, w/v) were used as positive and negative control, respectively. The mean dpm obtained with melatonin and nimesulide treatment at all concentrations were not significantly different (P>0.05) from that of AOO. The stimulation index (SI) values of melatonin and nimesulide at different concentrations were close to 1. The results of the present study using the standard LLNA approved by US Interagency Coordinating Committee in the Validation of Alternative Methods (ICCVAM) indicate that melatonin and nimesulide are not skin sensitizers. However, since LLNA has shown false negatives with many drugs, clinical trials are certainly needed to exclude the possibility of a weak or delayed type skin sensitization reaction. Further studies using modified LLNA procedures (extended exposure, alternative vehicle systems, pre-abrasion, etc.) may be useful in identifying the weak or delayed type skin sensitization reactions.

Celebrating 150 years of care at the Royal Marsden Hospital

The Royal Marsden Hospital, which provides care and treatment to patients with cancer and their families, celebrates its 150th anniversary this year. The Royal Marsden Hospital first opened its doors to patients with cancer in 1851. It was founded by the surgeon Dr William Marsden, whose wife died from cervical cancer. Her last few months were described as ‘full of misery and pain’. It was perhaps her misery and death that inspired him to found the Free Hospital for cancer sufferers (now named The Royal Marsden Hospital in his honour). Since its foundation, it has developed into a nationally and internationally respected cancer hospital, and has expanded from its original Chelsea, London home to a second site in Sutton.

Rationing versus rationality: observations from outside the United States

This commentary takes up A. David Paltiel's invitation to reflect on how to promote the use of decision analysis and cost-effectiveness analysis in health. From the perspective of a health services researcher outside the U.S. system, I make 3 arguments. First, the unthinking use of the term rationing for all applications of cost-effectiveness analysis distorts research priorities and may jeopardize wider public support. Second, public skepticism about decision and cost-effectiveness analysis (and thus the skepticism of decision makers) is well founded when ethical dimensions of these methods are not considered. We must continue to refine our methods to take account of societal values. Third, the United States may have particular problems in adopting more rational decision making in health care. The dominance of for-profit institutions in the U.S. health care system erodes the social legitimacy on which other systems depend to improve the rationality of health care decision making.