Interactions between epidermal keratinocytes and dermal fibroblasts play an important role in regulating tissue homeostasis and repair. Nevertheless, little is known about the role of keratinocytes in the pathogenesis of keloid. In this study, we investigated the influence of normal skin- and keloid-derived keratinocytes on normal skin- and keloid-derived fibroblasts utilizing a serum-free indirect coculture system. The keloid-derived fibroblasts showed a greater proliferation and minimal apoptosis when cocultured with normal skin- or keloid-derived keratinocytes, and the results were most significant in the latter. This difference was not observed when the fibroblasts were treated with conditioned medium obtained from normal skin- and keloid-derived keratinocytes. Nevertheless, conditioned medium-treated groups showed more proliferation and less apoptosis compared to the nonconditioned medium-treated control groups. We also analyzed the profile of factors involved in cell growth and apoptosis in fibroblasts cocultured with keratinocytes. Extracellular signal-regulated kinase and c-Jun N-terminal kinase phosphorylations and expression of Bcl-2 and transforming growth factor-beta1 were all significantly upregulated in the fibroblasts cocultured with keloid-derived keratinocytes. Together, these results strongly suggest that the overlying keratinocytes of the keloid lesion play an important role in keloidogenesis by promoting more proliferation and less apoptosis in the underlying fibroblasts through paracrine and double paracrine effects.
Competitive inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (the statins) that inhibit the synthesis of mevalonic acid are in wide use for treatment of hypercholesterolemia. Although antitumor effects on a variety of cell types have been reported for statins, the effect of simvastatin (one of the statins) on human melanoma cell lines is not known. Here, we report antitumor effects of simvastatin on human melanoma cell lines. We treated human melanoma cell lines, A375M, G361, C8161, GAK, and MMAc with simvastatin in various concentrations for 1 to 3 days. To investigate the antitumor effect of simvastatin, we analyzed cell viability, morphologic changes, reversibility of inhibition by geranylgeranyl pyrophosphate and farnesyl pyrophosphate, apoptosis and the cell cycle. Simvastatin treatment reduced cell viability in all five melanoma cell lines. The different melanoma cell lines, however, displayed different sensitivities to simvastatin. The addition of geranylgeranyl pyrophosphate to A375M and G361 cells in the presence of simvastatin completely restored the viability of cells, but the addition of farnesyl pyrophosphate did not. DNA fragmentation assay showed that simvastatin induced apoptosis in A375M and G361 cells. Simvastatin caused a G1 arrest in G361 and MMAc cells. Consistent with the cell cycle arrest, simvastatin caused an increase in the mRNA levels of p21 and p27 on G361 and MMAc cells. We conclude that simvastatin has an antitumor effect on human melanoma cells in vitro via apoptosis and cell cycle arrest. These results suggest that simvastatin may be an effective anticancer drug for malignant melanoma.
High-efficiency visible light emission in N-and-B-doped 6H-SiC epilayers was observed in photoluminescence measurements at room temperature. The orange-yellow light emission due to the recombination of donor-acceptor pairs ͑DAPs͒ has a broad spectrum with a peak wavelength of 576 nm and a full width at half maximum of 110 nm at 250 K. The high B concentration of more than 10 18 cm −3 improves the emission efficiency of the DAP recombination at a high temperature. Compared with the photoluminescence spectrum of GaN at 10 K, a high quantum efficiency of 95% was estimated for the highly B-doped sample. From time-resolved photoluminescence measurements, a DAP recombination time of 5.0 ms was obtained, which is in good agreement with the calculated value by the rate equation with the assumption of a 95% internal quantum efficiency. This is quite promising as a light-emitting medium by optical pumping, as well as monolithic light sources combined with nitride-based light-emitting diodes grown on the DA-doped SiC epilayer.
This splinted lymphedema model closely simulates the volume response, histopathology, and lymphography characteristics of human acquired lymphedema. Given these similarities to human lymphedema, this refinement of a mouse hindlimb model of acquired lymphedema represents a promising platform for the study of lymphatic vascular insufficiency and for the evaluation of new therapeutic modalities.
Lymphedema is known to be caused by many pathologic conditions; however, its correct diagnosis and optimal therapeutic strategies remain to be established. In this report, we describe an experimental model for acquired lymphedema in the lower extremity of the mouse that creates a lymphatic block in the groin induced by both radiation treatment and surgical division of the superficial and deep lymphatics. To evaluate the lymphatic system in this model, an indocyanine green fluorescence-sensitive camera system was used. This model has the advantages of relative technical simplicity and cost-effective use of a rodent animal model. Furthermore, a greater range of research tools such as antibodies and various databases are available for mice. This mouse model may be useful to anyone modeling lymphedema mechanisms, by providing a defined molecular context.
We evaluated a new standardized adjuvant corticosteroid therapy to prevent recurrence after surgical keloid or hypertrophic scar excision. Using this method, we achieved low recurrence rates.
These results suggest that the anteroposterior relationship was not significantly different between the groups, but the transversal relationship was better in the two-stage group than in the one-stage group.
The microbial mats responsible for biological desulfurization from biogas in a full-scale anaerobic digester were characterized in terms of their structure, as well as their chemical and microbial properties. Filament-shaped elemental sulfur 100-500 μm in length was shown to cover the mats, which cover the entire headspace of the digester. This is the first report on filamentous sulfur production in a non-marine environment. The results of the analysis of the mats suggest that the key players in the sulfide oxidation and sulfur production in the bio-desulfurization in the headspace of the digester were likely to be two sulfide-oxidizing bacteria (SOB) species related to Halothiobacillus neapolitanus and Sulfurimonas denitrificans, and that the microbial community, cell density, activity for sulfide oxidation varied according to the environmental conditions at the various locations of the mats. Since the water and nutrients necessary for the SOB were provided by the digested sludge droplets deposited on the mats, and our results show that a higher rate of sulfide oxidation occurred with more frequent digested sludge deposition, the habitat of the SOB needs to be made in the lower part of the headspace near the liquid level of the digested sludge to maintain optimal conditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.