Short-term effects of 448 kilohertz radiofrequency stimulation on supraspinatus tendon elasticity measured by quantitative ultrasound elastography in professional badminton players: a double-blinded randomized clinical trial

Objective: To study changes in supraspinatus tendon elasticity after a 448 kHz capacitive resistive monopolar radiofrequency (CRMR) intervention in professional badminton players. Design: Double-blinded randomized clinical trial. Setting: All participants were recruited in a private care practice. Participants were randomized to receive either a CRMR treatment (n ¼ 19) or placebo (n ¼ 19). Subjects: Professional badminton players (n ¼ 38). Intervention: A total of nine intervention (three per week) with CRMR at 448 kHz were carried out in the experimental group. The same intervention without an active CRMR current was carried out in the control group. Main measures: Mean values of three different regions of the supraspinatus tendon were reported at baseline (T1), immediately after the intervention (T2) and one week after the end of the whole intervention program (T3) using quantitative ultrasound strain elastography (SEL). Results: There were statistically significant differences in the supraspinatus tendon elasticity immediately after the intervention (p¼ <.001) and one week after the end of the whole intervention program (p¼.001). Conclusion: CRMR at 448 kHz produces significant changes in supraspinatus tendon elasticity after an intervention program of three weeks and those changes last for a week when compared to control group

The effect of heat shocks in skin rejuvenation

The formation of wrinkles, one of the aspects of aging skin, results as a consequence of a degenerated dermis. The aged protein network, muscle contractions and gravitation result in wrinkling of the skin. Currently, in the cosmetic industry, treatments for skin rejuvenation are rapidly evolving. Only a few techniques are used to counteract the aging dermis. One of the most promising areas is non-ablative laser techniques. These techniques have clinically been tested. However, the physiological background remains to be established. It is hypothesized that laser induced heat in the skin causes a heat shock and a subsequent heat shock response by the dermal fibroblasts. This heat shock response is said to stimulate, through heat shock proteins, the collagen synthesis by these cells. Subsequently, the laser has next to the thermal effect also a photochemical effect, where the photons are absorbed by cytochrome-c proteins, located on the cell membranes of the fibroblasts, and by doing so enhance the oxidative phosphorylation process, which in turn would result in a positively stimulated metabolism of the cell resulting in synthesizing more proteins, such as collagen. The present thesis focuses on the influence of the thermal effect on the collagen production of human dermal fibroblasts in culture and in ex-vivo skin. A model was developed that describes the interaction of laser light with skin resulting in the generation of heat. This model was combined with a transport model to describe the distribution of this heat through the skin. The model was used to determine the optimal laser conditions for heating and to describe the temperature distribution in the skin as a function of time. To investigate the response of human skin to heat shocks, the initial research was performed on cell cultures. Here, human dermal fibroblasts were cultured and exposed to heat shocks of 45°C and 60°C, respectively, and with pulse duration of 2 seconds. The results of this study showed that these heat shocks enhanced the collagen type I synthesis. Subsequently, a study was performed with heat shocks of 45°C and 60°C that were applied for 2, 4, 8, 10 and 16 seconds. The conclusion from this study is that 8 to 10 second pulses at 45°C are the maximum exposure time range at which the collagen type I synthesis is optimal. In addition, viable ex-vivo human skin samples were immersed into heated PBS of 45°C and 60°C. The 45°C heat shock does not create damage at all, while the 60°C heat shock shows initial damage around the cells in the skin. It was demonstrated that procollagen type I as well as type III were upregulated by both 45°C and 60°C heat shocks. Subsequently, a pilot study of a laser induced heat shock on ex-vivo skin study was performed. The results of this research demonstrated that the 45°C laser induced heat shocked did not damage the skin samples. The 60°C laser induced heat shock, on the other hand, demonstrated the presence of hsp27 in the area of the cells, and indication of early damage. The gene expression results revealed that the 45°C heat shocks upregulated procollagen type I. In conclusion, it has been shown in this thesis that a heat shock of 45°C applied to fibroblasts or in ex-vivo skin results in upregulation of in collagen heat shock gene expression. Furthermore, the cell studies showed the relevance of the combination of time and temperature; an optimal exposure time range of 8 to 10 seconds at 45°C to achieve the highest amount of collagen type I was found. Also the harmful nature of a 60°C heat shock was revealed. Showing that collagen synthesis can be enhanced by the 45°C heat shock is another step towards understanding the physiological pathways that lead to skin rejuvenation

Pulsed heat shocks enhance procollagen type I and procollagen type III expression in human dermal fibroblasts

Background: The formation of wrinkles is associated with degeneration of the collagen matrix. For regeneration of the matrix, fibroblasts need to be stimulated in producing new collagen. Aims: In this study, the effect of short-pulsed heat shocks on gene expression of procollagen type I, procollagen type III, heat shock protein (hsp)27, hsp47 and hsp70 and on the expression of remodeling markers, procollagen type I carboxy-terminal peptide (P1P) and carboxy-terminal telopeptide of type I (ICTP), of human dermal fibroblasts in vitro, is investigated. Materials and Methods: Temperatures of 45 °C and 60 °C were used for the heat shocks. The proliferation rates, viability and metabolic activity were measured directly after the pulsed heat shocks and quantitative PCR was performed at five different time points after the heat shocks. Enzyme Immuno Assays were performed to determine the concentrations of P1P and ICTP. Results: A decreased proliferation rate of the 60 °C heat shocked cells was shown, whereas the viability and metabolic activity did not differ. Furthermore, gene expressions were upregulated in both 45 °C and 60 °C heat-shocked cells. However, remodeling marker analyses showed a larger amount of collagen produced by 60 °C heat-shocked cells. Conclusion: It can be concluded that these findings, together with upregulation in gene expression, show that it is possible to stimulate the cells to produce more collagen with short-pulsed heat shock

Protein motions, dynamic effects and thermal stability in dihydrofolate reductase from the hyperthermophile thermotoga maritima

Dihydrofolate reductase (DHFR) has long been used as a model system in studies of the relationship between enzyme structure and catalysis. DHFR from the hyperthermophilic bacterium Thermotoga maritima (TmDHFR) is substantially different to other chromosomal DHFRs. It is dimeric where most others are monomeric, it lacks the conformational behaviour of monomeric DHFRs, and the kinetics of the catalysed reaction are significantly different. Experimental and computational studies of TmDHFR and comparison to other DHFRs have yielded deep insights into the role of enzyme motions and dynamics in catalysis. Mutational studies and formation of hybrids between TmDHFR and a monomeric homologue have demonstrated that dimerisation is required for extreme thermostability, but also leads to an inability to adequately close the active site with detrimental effects for the speed of the catalysed reaction. However, in common with other DHFRs there is no involvement of large-scale enzyme motions in the chemical reaction itself and dynamic coupling to the reaction coordinate is efficiently minimised. Studies of DHFRs from hyperthermophilic organisms and comparisons to their mesophilic counterparts remain a rich source of information on the fundamental nature of enzyme catalysis