Identification of three novel SRD5A2 mutations in Chinese patients with 5α-reductase 2 deficiency / 亚洲男科学杂志(英文版)

In this study, we investigated the genetics, clinical features, and therapeutic approach of 14 patients with 5α-reductase deficiency in China. Genotyping analysis was performed by direct sequencing of PCR products of the steroid 5α-reductase type 2 gene (SRD5A2). The 5α-reductase activities of three novel mutations were investigated by mutagenesis and an in vitro transfection assay. Most patients presented with a microphallus, variable degrees of hypospadias, and cryptorchidism. Eight of 14 patients (57.1%) were initially reared as females and changed their social gender from female to male after puberty. Nine mutations were identified in the 14 patients. p.G203S, p.Q6X, and p.R227Q were the most prevalent mutations. Three mutations (p.K35N, p.H162P, and p.Y136X) have not been reported previously. The nonsense mutation p.Y136X abolished enzymatic activity, whereas p.K35N and p.H162P retained partial enzymatic activity. Topical administration of dihydrotestosterone during infancy or early childhood combined with hypospadia repair surgery had good therapeutic results. In conclusion, we expand the mutation profile of SRD5A2 in the Chinese population. A rational clinical approach to this disorder requires early and accurate diagnosis, especially genetic diagnosis.

Decreased hepatic glucose production in obese rats by dipeptidyl peptidase-IV inhibitor sitagliptin / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Dipeptidyl peptidase-IV (DPP-4) inhibitors are now used to improve postprandial glycemic control in type 2 diabetes. However, their effects on hepatic glucose production (HGP) in obesity are not clear. This study was designed to test the hypothesis that gluconeogenesis and HGP can be modulated by DPP-4 inhibitors in obesity.</p><p><b>METHODS</b>Sprague Dawley male rats were divided into four groups, each on a different diet: general rat chow, n = 10 (G); G + sitagliptin, n = 10; high fat chow (obesity), n = 10 (55% fat calories, HFO); HFO + sitagliptin, n = 10. After 10 weeks, the rats were fasted overnight and glucose metabolism was determined using 3-(3)H-glucose and (14)C-glycerol as tracers.</p><p><b>RESULTS</b>Glycerol rate of appearance (P < 0.00001), plasma glycerol (P < 0.05) and free fatty acid (FFA) (P < 0.05) concentrations, and HGP (P < 0.05) were decreased in HFO + sitagliptin group compared with HFO group, but there was no significant difference between G and G + sitagliptin groups (P > 0.05). Gluconeogenesis in HFO group was five times of that in G rats (P < 0.01), but was significantly declined in HFO + sitagliptin group (P < 0.0001).</p><p><b>CONCLUSIONS</b>Gluconeogenesis and HGP were inhibited by sitagliptin in high fat-induced obese rats due to decreased glycerol availability, which was a result of reduced glycerol release from adipose tissues. The finding suggests that sitagliptin is potentially useful for controlling fasting glucose in obesity, thereby delaying or preventing the development of diabetes.</p>

Preliminary study on in vitro tendon engineering using tenocytes and polyglycolic acids / 中华外科杂志

<p><b>OBJECTIVE</b>To find out the feasibility of tendon engineering in vitro using expanded tenocytes and polyglycolic acids (PGA).</p><p><b>METHODS</b>Tenocytes were isolated using tissue explant method and expanded in vitro. Tenocytes (20 x 10(6)) at the second passage were collected and then seeded onto PGA unwoven fibers to form a cell-scaffold construct in a shape of tendon. The constructs were cultured in DMEM with 20% FBS for 1 week. The cell-scaffold constructs were then cultured under constant tension generated by a U-shaped spring (n = 5), which served as experimental group, or cultured without tension (n = 4), which served as control group 1. PGA fibers alone were cultured (n = 3), which served as control group 2. Small fragments at the end of the constructs were harvested at 2, 4 and 6 weeks respectively for histological and immunohistochemistry (IHC) analysis. Six-week samples were also evaluated by transmission electron microscope (TEM) and mechanical test.</p><p><b>RESULTS</b>No obvious difference was observed among the three groups at 2 weeks grossly and histologically as the constructs remained to be mainly undegraded PGA fibers. By 4 weeks, a neo-tendon was formed in the experimental group and control group 1 grossly, and histology and IHC revealed the formation of collagen fibers. In contrast, PGA fibers alone in control group 2 were mostly degraded. At 6 weeks, tendons of control group 1 were much thicker [(2.55 +/- 0.18) mm in diameter] than those of experimental group [(1.44 +/- 0.13) mm in diameter]. Periodical striae were observed in collagen fibers of experimental group and control group 1 by TEM. However, histology of tendons in experimental group revealed longitudinally aliened collagen fibers, which resembled the structure of normal tendon more closely than that of control group 1 tendons. Furthermore, the maximum tensile stress (N/mm(2)) of experimental group (1.107 +/- 0.327) was greater than that of control group 1 (0.294 +/- 0.138) (P < 0.05).</p><p><b>CONCLUSION</b>It is possible to use an engineering to construct tendon tissue in vitro. Periodical strain generated by bioreactor may be the optimal mechanical stimulation, which is currently under investigation.</p>