Recently, minimally invasive approach via limited incision becomes one of the rapidly developing strategy in cardiac surgery as it gives less surgical trauma and is more satisfactory to the patients in respect to operative scar although the surgical technique is more demanding. Here, we report two cases of aortic valve replacement via limited transsternal incision. The methodology is described with review of the relevant literature.

BACKGROUND: It has been suggested that the regulation of hair growth might involve complex interaction between dermal papilla cells and hair matrix cells. Dermal papilla cells secrete diffusible factors that would act an hair matrix cells. During anagen the papilla appears to have prominent capillary loop, whereas in telogen it is nonvascularized. Vascular endothelial growth factor(VEGF) was recently reported to be produced by dermal papilla cells in rats. OBJECTIVES: We performed this study in order to evaluate the effect of VEGF on human hair growth in vitro and on the proliferation of dermal papilla cells and to define the splice forms of VEGF. METHODS: To detect the isoforms of VEGF, RT-PCR was performed on RNA isolated from dermal papilla cells and RT-PCR products were hybridized with VEGF-specific oligonucleotide probe located in exon 4. Isolated human hair follicles were cultured with various concentrations of VEGF165 and VEGF121. Hair follicle growth was measured by an Olympus inverted microscope with an eyepiece measuring graticule. RESULTS: The following results were obtained from this study. 1. Southern hybridization and size calculation of RT-PCR products revealed that mRNA species corresponding to 121, 165, 189, and 206 amino-acid forms of VEGF were praduced by cultured human dermal papilla cells. 2. 10 ng/ml of rhVEGF165, 0.1 ng/ml of rhVEGF165 and 10 ng/ml of rhVEGF121 stimulated follicle elongation in vitro(p < 0.05). 3. rhVEGF165 and rhVEGF121 had no effect on the numbers and thymidine incorporation of dermal papilla cells. CONCLUSION: These results suggest that VEGF is produced by dermal papilla cells and is able to promote hair growth in vitro. Increased hair growth by VEGF might occur other than by proliferation of dermal papilia cells.