Dry heat, moist heat and body fat: are heating modalities really effective in people who are overweight?

Surface heating modalities are commonly used in physical therapy and physical medicine for increasing circulation, especially in deep tissues, to promote healing. However, recent evidence seems to indicate that in people who are overweight, heat transfer is impaired by the subcutaneous fat layer. The present investigation was conducted on 10 subjects aged 22-54 years, whose body mass index averaged 25.8+/-4.6. Subcutaneous fat above the quadriceps muscle varied from 0.51 to 0.86 cm of thickness. Three heating modalities were examined: the application of dry heat with a commercial chemical heat pack, hydrocollator heat packs (providing a type of moist heat), and a whirlpool, where conductive heat loss through water contact would be very high. The temperature of the skin and the temperature in the muscle (25 mm below the skin surface) were assessed by thermocouples. The results of the experiments showed that for heating modalities that are maintained in skin contact for long periods of time, such as dry heat packs (in place for 6 hours), subcutaneous fat did not impair the change in deep muscle temperature. In contrast, when rapid heat modalities were used, such as the hydrocollator and the whirlpool (15 minutes of sustained skin contact), the transfer of heat from the skin to deep muscle was significantly impaired in people with thicker subcutaneous fat layers. We observed that the greater the impairment in heat transfer to muscle from skin covered by body fat, the warmer the skin temperature increase during the modality.

The controlled release, bioactivity and osteogenic gene expression of Quercetin-loaded gelatin/tragacanth/ nano-hydroxyapatite bone tissue engineering scaffold

In this study, a Gelatin/Tragacanth/Nano-hydroxyapatite scaffold was fabricated via freeze-drying method. A highly porous scaffold with an average pore diameter of 142 µm and porosity of 86% was found by the micro-computed tomography. The mean compressive strength of the scaffold was about 1.5 MPa, a value in the range of the spongy bone. The scaffold lost 10 wt.% of its initial weight after 28 days soaking in PBS that shows a fair degradation rate for a bone tissue engineering scaffold. Apatite formation ability of the scaffold was confirmed via scanning electron microscopy, X-ray diffraction and Fourier transforming infrared spectroscopy, after 28 days soaking in simulated body fluid. The scaffold was able to deliver 93% of the loaded drug, Quercetin, during 120 h in phosphate-buffered solution, in a sustainable manner. The MTT assay using human bone mesenchymal stem cells showed 84% cell viability of the Quercetin-loaded scaffold. The expression of the osteogenic genes including Col I, Runx-2, BGLAP (gene of osteocalcin), bFGF, SP7 (gene of osterix) and SPP1 (gene of osteopontin) were all upregulated when Quercetin was loaded on the scaffold, which indicates the synergetic effect of the drug and the scaffold.