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The heat transport within living biological tissue is a complicated process coupled with various physiological activities. The nonhomogeneous inner anatomical structure leads to an essential difference from classical heat transfer. The generalized model of bioheat transfer involving the relaxation mechanism as well as nonequilibrium heat transfer is first proposed to explore the heat transport properties within living biological tissues. Due to the volume averaging theory, the new local instantaneous energy equations of blood and tissue are constructed separately by introducing the phase lags, in which the delay effect between the heat flux and temperature gradient absent in existing generalized models is considered. The effective phase lags covering the delay effect and nonequilibrium effect are obtained on this basis. A detailed parametric study has been conducted to estimate the values of these effective phase lags and evaluate their contributions on heat transport within living biological tissues. The results state that the effective phase lags depend on the anatomical structure of tissues and its physical properties. The delay effect is dominated in general and has a higher temperature elevation than that induced by nonequilibrium effect only. [ABSTRACT FROM AUTHOR]

An increasing number of natural antioxidants f om medicinal plants have been shown safe and effective to human health. Abelmoschus manihot (L.) Medic flower is a traditional medicine with high flavonoid content. In this study we investigated the antioxidant activities of total flavonoid extract from A. manihot (L.) Medic flowers (TFAE) in vivo and in vitro and explored the expression of antioxidant genes in mice. In the in vitro assay, the scavenging activities of TFAE were evaluated against DPPH radical, superoxide radical, hydroxyl radical. Meanwhile, fem e reducing antioxidant power and inhibiting lipid peroxidation of TFAE were investigated. In the in vivo assay, male Kunming mice were randomly divided into six groups (n = 10/group): (1) Normal control, (2) GAL (D-galactose) model, (3) GALA (positive control, GAL+ ascorbic acid), (4) GALL (GAL + 40 mg total flavonoid of TFAE/kg body weight), (5) GALM (GAL + 80 mg total flavonoid of TFAE/kg body weight), (6) GALH (GAL + 160 mg total flavonoid of TFAE/kg body weight). After 42 days, protective effects of TFAE were determined by biochemical studies and Real-time PCR. TFAE had strong scavenging activities against DPPH radical (IC50 = 7.98 μg/ ml), superoxide anion radical (IC50= 14.96 μg/ml), hydroxyl radical (IG-0 - 129.02 μg/ml) and high ferric reducing antioxidant power (A700mm = 2.32) compared to ascorbic acid. However, the inhibiting of lipid peroxidation was lower than that ofBHA. GAL-induced mice that were administered TFAE showed significant elevation in serum and liver activities of antioxidant enzymes (CAT, GPx, SOD) and T-AOC whereas reduction in MDA production in a dose-dependent manner compared with mice in GAL model group. Furthermore, the mRNA expression of antioxidant genes also increased in TFAE treatment groups significantly. Tltese results suggested that TFAE exhibited antioxidant activities possibly regulated through antioxidant genes expression. TFAE may represent a potential natural source fo r reducing the risk of diseases and preventing aging. [ABSTRACT FROM AUTHOR]

The drug camptothecin has a wide range of antitumor effects in cancers including gastric cancer, rectal and colon cancer, liver cancer, and lung cancer. Camptothecin-based drugs inhibit topoisomerase 1 (Topo 1), leading to destruction of DNA, and are currently being used as important chemotherapeutic agents in clinical antitumor treatment. However, the main obstacle associated with cancer therapy is represented by systemic toxicity of conventional anticancer drugs and their low accumulation at the tumor site. In addition, low bioavailability, poor water solubility, and other shortcomings hinder their anticancer activity. Different from traditional pharmaceutical preparations, nanotechnology-dependent nanopharmaceutical preparations have become one of the main strategies for different countries worldwide to overcome drug development problems. In this review, we summarized the current hotspots and discussed a variety of camptothecin-based nanodrugs for cancer therapy. We hope that through this review, more efficient drug delivery systems could be designed with potential applications in clinical cancer therapy. [ABSTRACT FROM AUTHOR]

Cisplatin is a chemotherapeutic drug commonly used in clinics. However, acquired resistance confines its application in chemo-therapeutics. To overcome the acquired resistance to cisplatin. it is reasoned, based on our previous findings of mediation of cellular responses by [Gd@C82(OH)22)n nanoparticles, that [Gd@C82(OH)22)n may reverse tumor resistance to cisplatin by reactivating the impaired endocytosis of cisplatin-resistant human prostate cancer (CP-r) cells. Here we report that exposure of the CP-r PC-3-luc cells to cisplatin in the presence of nontoxic [Gd@C82(OH)22]n not only decreased the number of surviving CP-r cells but also inhibited growth of the CP-r tumors in athymic nude mice as measured by both optical and MRI. Labeling the CP-r PC-3 cells with transferrin, an endocytotic marker, demonstrated that pretreatment of the CP-PC-3-luc cells with [Gd@C82(OH)22]n enhanced intracellular accumulation of cisplatin and formation of cisplatin-DNA adducts by restoring the defective endocytosis of the CP-r cancer cells. The results suggest that [Gd@C82(OH)22]n nanoparticles overcome tumor resistance to cisplatin by increasing its intracellular accumulation through the mechanism of restoring defective endocytosis. The technology can be extended to other challenges related to multidrug resistance often found in cancer treatments. [ABSTRACT FROM AUTHOR]