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Abstract: Leptin is thought to be not only a satiety factor but also a stimulator of angiogenesis. We examined leptin, PPARγ2, and vascular endothelial growth factor (VEGF) expression in bovine intramuscular preadipocyte (BIP) cells during proliferation. The cells were seeded at 0.85 × 104 cells/cm2 and collected every day until the fifth day after passage. Leptin mRNA was present in the cells between days 2 and 4, as indicated by RT-PCR analysis. Western blot analysis showed a band for leptin at approximately 16 kDa on all of the days during growth, and the cytoplasmic concentration of leptin was highest on day 2 and decreased gradually thereafter. A PPARγ2 band at approximately 54 kDa was also observed on all days. The concentration was highest on day 2 and decreased thereafter, which is similar to the expression pattern of leptin. In constant, the expression level of VEGF protein did not change while in culture. We have demonstrated that BIP cells can synthesize both leptin and PPARγ2, with maximal synthesis occurring during maximal proliferation. Given the role of leptin in angiogenesis, we speculate that leptin is involved in the neovascularization of adipose tissue, because new organization of adipose tissue requires the growth of new blood vessels. [Copyright &y& Elsevier]

A survey of biophysical and biomedical applications of free-electron lasers (FELs) is presented. FELs are pulsed light sources, collectively operating from the microwave through the x-ray range. This accelerator-based technology spans gaps in wavelength, pulse structure, and optical power left by conventional sources. FELs are continuously tunable and can produce high-average and high-peak power. Collectively, FEL pulses range from quasicontinuous to subpicosecond, in some cases with complex superpulse structures. Any given FEL, however, has a more restricted set of operational parameters. FELs with high-peak and high-average power are enabling biophysical and biomedical investigations of infrared tissue ablation. A midinfrared FEL has been upgraded to meet the standards of a medical laser and is serving as a surgical tool in ophthalmology and human neurosurgery. The ultrashort pulses produced by infrared or ultraviolet FELs are useful for biophysical investigations, both one-color time-resolved spectroscopy and when coupled with other light sources, for two-color time-resolved spectroscopy. FELs are being used to drive soft ionization processes in mass spectrometry. Certain FELs have high repetition rates that are beneficial for some biophysical and biomedical applications, but confound research for other applications. Infrared FELs have been used as sources for inverse Compton scattering to produce a pulsed, tunable, monochromatic x-ray source for medical imaging and structural biology. FEL research and FEL applications research have allowed the specification of spin-off technologies. On the horizon is the next generation of FELs, which is aimed at producing ultrashort, tunable x rays by self-amplified spontaneous emission with potential applications in biology. [ABSTRACT FROM AUTHOR]