Facilitated diffusion

can promote microtubule assembly, because, upon encountering a growing nucleus or the microtubule wall, random GTP-tubulin sliding on their surfaces will increase the probability of association to the target sites (nucleation sites or MT ends). This is an original explanation for understanding the apparent discrepancy between the high rate of microtubule elongation and the low rate of tubulin association at the microtubule ends in the viscous cytoplasm. The mechanism of facilitated diffusion requires an attraction force between two tubulins, which can result from the sharing of multivalent counterions. Natural polyamines (putrescine, spermidine, and spermine) are present in all living cells and are potent agents to trigger tubulin self-attraction. By using an analytical model, we analyze U0126 concentration the implication of facilitated diffusion mediated by polyamines on nucleation and elongation of microtubules.

In vitro experiments using pure tubulin indicate that the promotion of microtubule assembly by polyamines is typical of facilitated diffusion. The results presented here show that polyamines can be of particular importance for the regulation of the microtubule network in vivo and provide the basis for further investigations into the effects of facilitated diffusion on cytoskeleton dynamics.”
“Background This clinical study reports our experience with endovenous laser treatment (ELT) in which external air cooling is used without classic tumescent anesthesia. Methods Two hundred thirty-two patients underwent ELT under general sedation. In group A (n=192), ELT was Epigenetics inhibitor performed with air cooling but without the concurrent use of tumescent anesthesia. In group B (n=40),

check details patients were treated using the traditional tumescent technique. The parameters were similar for both groups: 980-nm diode laser, power of 15W, and pulse duration of 1second. The laser fiber and catheter were manually withdrawn in 3-mm increments. Ultrasound was performed to reevaluate vein closure at the end of surgery and 2 and 8weeks and 1year after. During follow-up, complications such as burns, dyschromia, pain, and dysesthesia, as well as time used for surgery were recorded. Results A 96% closure rate was obtained in groups A and B at 2 and 8 weeks. This rate remained stable 1 year after the ELT procedure. Except for a higher percentage of ecchymoses in group B (55%) than in group A (0%) (p<0.001), no significant differences were observed for complications. With external air cooling, ELT took 17.5minutes to perform for the whole leg, compared with 38.5minutes when using tumescent anesthesia (p<0.05). Conclusion ELT surgery for the great saphenous vein can be safely performed using the air cooling method and is as efficacious as ELT done with tumescent anesthesia but takes significantly less time to perform.