Ultrasensitive and universal fluorescent aptasensor for the detection of biomolecules (ATP, adenosine and thrombin) based on DNA/Ag nanoclusters fluorescence light-up system.

We report here an ultrasensitive strategy based on the recognition-induced conformational alteration of aptamer and fluorescence turn-on abilities of guanine-rich (G-rich) DNA sequence in proximity to silver nanoclusters for adenosine triphosphate (ATP), adenosine (A) and thrombin (TB) detection. Herein, we designed two tailored DNA sequences noted as complementary DNA (abbreviated as c-DNA) and signal probe DNA (abbreviated as s-DNA), respectively. c-DNA is designed as a special structure consisting of a sequence complementary to aptamer at the 3'-end and a guanine-rich DNA sequence at the 5'-end; s-DNA contains a cytosine-rich sequence responsible for Ag NCs templated synthesis at the 3'-end and a link sequence (part of aptamer) complementary to partial of the c-DNA at the 5'-end. In the presence of target, the aptamer associated with the target, resulting in the formation of duplex DNA (dsDNA), the DNA-Ag NCs thereafter could close to the guanine-rich sequence, leading to enhanced fluorescence signal readout. The widespread application of the sensing system is achieved success in the detection of three biomolecules. ATP, adenosine and thrombin in the range of 0.5-8.0 µM, 0.5-7.0 µM and 50-900 nM could be linearly detected with the detection limits of 91.6 nM, 103.4 nM and 8.4 nM, respectively. This label-free and turn-on fluorescent sensing system employing the mechanism proposed here turns out to be sensitive, selective, and convenient for the detection of biomolecules without washing and separation steps.

A study on the effect of aqueous extract of Lobelia chinensis on colon precancerous lesions in rats.

This paper studies the effects of Lobelia chinensis on colon precancerous lesions and on colonic epithelial proliferation and apoptosis in DMH-induced rats. After two weeks of feeding, 50 Wistar rats were randomly divided into five groups, namely the normal group, model group, Lobelia chinensis low-dose group, medium-dose group and high-dose group. Lobelia chinensis was made into ACF model, and administered to experimental groups for 10 consecutive weeks. Control group was given equivalent amount of normal saline. After feeding for 10 weeks, the rats in each group were sacrificed and the changes in colonic ACF number of rats in experimental groups were observed, and the inhibition rates were calculated. The results showed that among the rats fed for 24 h and 48 h, the number of apoptotic cells in colonic crypts of rats in DMH group did not differ significantly from the control group, while the difference was obvious between the control group and Lobelia chinensis treatment groups. The medium and high doses, that is, 0.45 g/kg and 1.35 g/kg can significantly inhibit ACF formation (P<0.01). The inhibition rates of low, medium and high doses were 8.12%, 59.42% and 65.44%, respectively.

Enhancement of sodium caprate on intestine absorption and antidiabetic action of berberine.

Berberine, a plant alkaloid used in traditional Chinese medicine, has a wide spectrum of pharmacological actions, but the poor bioavailability limits its clinical use. The present aim was to observe the effects of sodium caprate on the intestinal absorption and antidiabetic action of berberine. The in situ, in vitro, and in vivo models were used to observe the effect of sodium caprate on the intestinal absorption of berberine. Intestinal mucosa morphology was measured to evaluate the toxic effect of sodium caprate. Diabetic model was used to evaluate antidiabetic effect of berberine coadministered with sodium caprate. The results showed that the absorption of berberine in the small intestine was poor and that sodium caprate could significantly improve the poor absorption of berberine in the small intestine. Sodium caprate stimulated mucosal-to-serosal transport of berberine; the enhancement ratios were 2.08, 1.49, and 3.49 in the duodenum, jejunum, and ileum, respectively. After coadministration, the area under the plasma concentration-time curve of berberine was increased 28% than that in the absence of sodium caprate. Furthermore, both berberine and coadministration with sodium caprate orally could significantly decrease fasting blood glucose and improve glucose tolerance in diabetic rats (P < 0.05). The hypoglycemic effect of coadministration group was remarkably stronger, and the areas under the glucose curves was decreased 22.5%, compared with berberine treatment group (P < 0.05). Morphologic analysis indicated that sodium caprate was not significantly injurious to the intestinal mucosa. The study demonstrates that sodium caprate could significantly promote the absorption of berberine in intestine and enhance its antidiabetic effect without any serious mucosal damage.

[Changes in the hemodynamics of rats with immunological liver fibrosis].

OBJECTIVE: To observe the changes in the hemodynamics of rats with immunological liver fibrosis and explore the pathogenesis of "blood stasis" in liver fibrosis. METHODS: Rat models of liver fibrosis were established by multiple intraperitoneal injections of pig serum. The hematocrit, blood viscosity at the shear rate of 150/s, 30/s, 5/s, and 1/s, serum markers for liver fibrosis, and serum transaminase levels were measured in the control and model rats. RESULTS: The hematocrit, blood viscosity at different shear rates, hyaluronic acid (HA), laminin (LN), procollagen type III (PCIII), type IV collagen (CIV), glutamic-pyruvic transaminase (ALT) and glutamic-oxaloacetic transaminase (AST) increased significantly in the rats with experimental liver fibrosis appeared as compared with those in the control rats. Positive correlations were noted between blood viscosity at different shear rates and serum concentrations of the fibrosis markers (HA, LN, PCIII, and CIV) in the model rats. CONCLUSION: The changes in the hemodynamics in rats with immunological liver fibrosis suggests the role of "blood stasis" in the pathogenesis of liver fibrosis and provide experimental evidence for therapies to "activate the blood circulation and dissipate blood stasis" for treatment of liver fibrosis.

Expression of Pkd2l2 in testis is implicated in spermatogenesis.

Pkd2l2 is a novel member of the polycystic kidney disease (PKD) gene family in mammals. Prominently expressed in testis, this gene is still poorly understood. In this study, reverse transcription polymerase chain reaction (RT-PCR) results showed a time-dependent expression pattern of Pkd2l2 in postnatal mouse testis. Immunohistochemical analysis revealed that Pkd2l2 encoded a protein, polycystin-L2, which was predominantly detectable in the plasma membrane of spermatocytes and round spermatids, as well as in the head and tail of elongating spermatids within seminiferous tubules in mouse testis tissue sections of postnatal day 14 and adult mice. A green fluorescent fusion protein of Pkd2l2 resided in the plasma membrane of HEK 293 and MDCK cells, suggesting that it functions as a plasma membrane protein. Overexpression of Pkd2l2 increased the intracellular calcium concentration of MDCK cells, as detected by flow cytometry. Collectively, these data indicated that Pkd2l2 may be involved in the mid-late stage of spermatogenesis through modulation of the intracellular calcium concentration.

The characterization of high-fat diet and multiple low-dose streptozotocin induced type 2 diabetes rat model.

AIM: Based on the previously established method, we developed a better and stable animal model of type 2 diabetes mellitus by high-fat diet combined with multiple low-dose STZ injections. Meanwhile, this new model was used to evaluate the antidiabetic effect of berberine. METHOD: Wistar male rats fed with regular chow for 4 weeks received vehicle (control groups), rats fed with high-fat diet for 4 weeks received different amounts of STZ once or twice by intraperitoneal injection (diabetic model groups), and diabetic rats were treated with berberine (100 mg/kg, berberine treatment group). Intraperitoneal glucose tolerance test and insulin tolerance test were carried out. Moreover, fasting blood glucose, fasting insulin, total cholesterol, and triglyceride were measured to evaluate the dynamic blood sugar and lipid metabolism. RESULT: The highest successful rate (100%) was observed in rats treated with a single injection of 45 mg/kg STZ, but the plasma insulin level of this particular group was significantly decreased, and ISI has no difference compared to control group. The successful rate of 30 mg/kg STZ twice injection group was significantly high (85%) and the rats in this group presented a typical characteristic of T2DM as insulin resistance, hyperglycemia, and blood lipid disorder. All these symptoms observed in the 30 mg/kg STZ twice injection group were recovered by the treatment of berberine. CONCLUSION: Together, these results indicated that high-fat diet combined with multiple low doses of STZ (30 mg/kg at weekly intervals for 2 weeks) proved to be a better way for developing a stable animal model of type 2 diabetes, and this new model may be suitable for pharmaceutical screening.