Optical phantoms with variable properties and geometries for diffuse and fluorescence optical spectroscopy.

Growing interest in optical instruments for biomedical applications has increased the use of optically calibrated phantoms. Often associated with tissue modeling, phantoms allow the characterization of optical devices for clinical purposes. Fluorescent gel phantoms have been developed, mimicking optical properties of healthy and tumorous brain tissues. Specific geometries of dedicated molds offer multiple-layer phantoms with variable thicknesses and monolayer phantoms with cylindrical inclusions at various depths and diameters. Organic chromophores are added to allow fluorescence spectroscopy. These phantoms are designed to be used with 405 nm as the excitation wavelength. This wavelength is then adapted to excite large endogenous molecules. The benefits of these phantoms in understanding fluorescence tissue analysis are then demonstrated. In particular, detectability aspects as a function of geometrical and optical parameters are presented and discussed.

Improved sample injection and illumination for multicapillary systems.

Multicapillary electrophoresis continues to see improvements in speed, robustness, and reliability. This paper reports on our work on two components belonging to a multicapillary sequencer developed in our group. Injection of the DNA samples into the capillaries was optimized to make it reproducible and to reduce the amount of sample volume required. An alternative laser illumination of the capillaries was also developed. Light intensity in the capillaries was increased as a result of a step-by-step scanning of the laser and the use of microlenses in front of the capillaries.

Comparison of a thermo-associating matrix and a liquid polymer.

Capillary electrophoresis is still widely used for DNA sequencing. The quality of the replaceable sieving matrix is a key area for massive sequencing with regard to speed and efficiency. The T25 polymer has been tested extensively and compared to poly(N,N-dimethylacrylamide) (PDMA). In terms of peak resolution, both polymers perform similarly. On the other hand, the run time is much shorter with the T25 polymer.

Characterization of a novel human anaplastic large cell lymphoma cell line tumorigenic in SCID mice.

L82, a novel anaplastic large cell lymphoma (ALCL) cell line was established from the pleural effusion of a 24-year-old patient with recurrent ALCL. L82 cells showed the typical morphologic features of ALCL cells with irregular, often indented, nuclear profiles, prominent nucleoli, and abundant cytoplasm. The immunoprofile of L82 corresponds to that seen typically in primary ALCL cells, with positivity for CD30, EMA, CD3, CD4, CD25, CD71, TIA1, and granzyme B; the cells were negative for EBV-related antigens. Cytogenetic analysis showed a complex, near triploid karyotype with 72-77 chromosomes, including the ALCL specific translocation t(2;5)(p23;q35). Chromosomal analysis revealed a number of secondary structural alterations including amplification of 7q21-31, 1q, and 6p, and gain of chromosomal material in 8q (affecting the c-myc gene). The rearrangement of the T-cell receptor-gamma locus shows that L82 is clonally derived from T-lineage lymphoid cells. mRNAs for interleukin 7 (IL-7), IL-8, IL-9, IL-10, TNF-beta, and for the IL-7 and IL-9 receptor were found. These data show that the T-helper cell (Th)1/Th2 balance was polarized to Th2. L82 were inoculated intraperitoneally into 4 week-old SCID mice and produced a disseminated tumor within 4-6 weeks. Morphological, immunohistochemical, and molecular genetic investigation confirmed that the xenograft and the original ALCL tumor were identical. SCID mice xenografted with the human ALCL cell line, L82, provide a useful model system for the investigation of the biology of ALCL and of new therapeutic approaches, such as specific immunotherapy.