Ghrelin contributes to derangements of glucose metabolism induced by rapamycin in mice

AIMS/HYPOTHESIS

Rapamycin impairs glucose tolerance and insulin sensitivity. Our previous study demonstrated that rapamycin significantly increases the production of gastric ghrelin, which is critical in the regulation of glucose metabolism. Here, we investigated whether ghrelin contributes to derangements of glucose metabolism induced by rapamycin.

METHODS

The effects of rapamycin on glucose metabolism were examined in mice receiving ghrelin receptor antagonist or with Ghsr1a gene knockout. Changes in GLUT4, c-Jun N-terminal kinase (JNK) and phosphorylated ribosomal protein S6 (pS6) were investigated by immunofluorescent staining or western blotting. Related hormones were detected by radioimmunoassay kits.

RESULTS

Rapamycin impaired glucose metabolism and insulin sensitivity not only in normal C57BL/6J mice but also in both obese mice induced by a high fat diet and db/db mice. This was accompanied by elevation of plasma acylated ghrelin. Rapamycin significantly increased the levels of plasma acylated ghrelin in normal C57BL/6J mice, high-fat-diet-induced obese mice and db/db mice. Elevation in plasma acylated ghrelin and derangements of glucose metabolism upon administration of rapamycin were significantly correlated. The deterioration in glucose homeostasis induced by rapamycin was blocked by D: -Lys3-GHRP-6, a ghrelin receptor antagonist, or by deletion of the Ghsr1a gene. Ghrelin receptor antagonism and Ghsr1a knockout blocked the upregulation of JNK activity and downregulation of GLUT4 levels and translocation in the gastrocnemius muscle induced by rapamycin.

CONCLUSIONS/INTERPRETATION

The current study demonstrates that ghrelin contributes to derangements of glucose metabolism induced by rapamycin via altering the content and translocation of GLUT4 in muscles.

Stable expression and integrated hepatitis B virus genome in a human hepatoma cell line

HepG2.2.15 cell is a widely used cell model for studying HBV (hepatitis B virus) in vitro. In these cells, the HBV genome is integrated in several sites of HepG2 cellular DNA. These multiple copies may have some influence on the cellular processes. We constructed a new plasmid, pSEH-Flag-HBV, and transfected it into HepG2 cells, and then screened it with hygromycin. We then used ELISA, PCR, and RT-PCR to detect the expression of HBV in these cell lines. A cell line that stably expressed hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) was established. Using Southern blotting analysis, we found that the HBV genome was integrated as a single copy in the cellular DNA. This cell line will be a useful alternative model for HBV studies.

Osteoporotic vertebral compression fractures: surgery versus non-operative management

This 12-month retrospective study compared pain relief, quality of life (QoL), treatment cost-effectiveness and complication rates in patients with acute osteoporotic vertebral compression fracture (OVCF) undergoing percutaneous vertebroplasty (PVP; n = 58), percutaneous kyphoplasty (PKP; n = 55), or conservative medical therapy (CMT; n = 55). After surgery, Cobb angle and vertebral height were significantly improved in the PKP group. PVP and PKP patients had significantly less pain immediately after surgery than CMT patients, but this difference disappeared between weeks 2-8, only to return from months 6-12. QoL was significantly better among the surgical groups after surgery and was lower in the CMT group than in the surgical groups. Treatment times were shorter with PVP and PKP, but costs were lower with CMT. The rate of secondary fractures during follow-up was greater with CMT. Overall, PVP was considered the first choice treatment for OVCF with refractory pain.

Telescope alignment from sparsely sampled wavefront measurements over pupil subapertures

We present a simple formalism that has proven useful in on-axis alignment of two-element telescopes when wavefront information is available from only a limited region (here two noncontiguous subapertures) of the pupil. Misalignments cause predictable full-aperture aberrations, which in turn cause predictable tip/tilt modes in the subapertures. For the most useful case in which secondary mirror tilts are independently constrained by optical monitoring, the four subaperture tip/tilt modes provide enough information to solve for the state of misalignment uniquely. A practically important and intuitively appealing simplification of this inversion occurs if the tip/tilts of the two subapertures are first transformed into a new basis consisting of differential and common-mode tilts in each of the x and y directions. Then the matrices interpreting subaperture modes as full-aperture aberrations and those in turn as mechanical misalignments become diagonal, so the mechanical adjustment required to align each degree of freedom is just a constant sensitivity multiplying one of the measured differential or common-mode tilt basis modes. Knowing that this simplification occurs allows rapid empirical calibration of sensitivities in the lab and then deterministic alignment, simply and transparently, with no need for ray tracing to model the optical effects of the adjustments at each step of the alignment.

Mechanical stretch inhibits adipogenesis and stimulates osteogenesis of adipose stem cells

A reciprocal relationships between osteogenesis and adipogenesis has been observed in vitro and in vivo, and mechanical stretch has been believed to be a regulating factor of osteo-adipogenic axis differentiation of mesenchymal stem cells. In this study, rat adipose stem cells (ASCs) were isolated and cultured in adipogenic or normal medium. Their exposure to cyclic mechanical stretch (2000 με, 1 Hz) in the presence of adipogenic medium decreased mRNA and protein level of PPAR-γ, and increased Runx2 mRNA and protein levels as well as Pref-1 mRNA level, compared to static samples. ASCs cultured in normal medium without adipogenic induction did not show any significant change in mRNA expression of PPAR-γ, Runx2, nor Pref-1 irrespective of mechanical loading. Stretching induced phosphorylation of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) during the induction period. It was concluded that mechanical stretch inhibited adipogenesis and stimulated osteogenesis of these ASCs in the presence of adipogenic medium and that ERK1/2 activation may be involved in the mechanical stress-induced trans-differentiation.

Angiotensin-(1–7) Inhibits Vascular Remodelling in Rat Jugular Vein Grafts via Reduced ERK1/2 and p38 MAPK Activity

This study evaluated the effect of angiotensin (Ang)-(1–7) on vascular remodelling in a rat autologous jugular vein graft model in which rats underwent autologous jugular vein graft transplantation (Ang-[1–7] and control groups) or sham surgery (sham group). The animals received continuous jugular infusion of Ang-(1–7) at 25 μg/kg per h (Ang-[1–7] group) or normal saline (control and sham groups) starting 3 days after surgery. Ang-(1–7) infusion reduced venous graft hyperplasia, vascular remodelling, extracellular signal-regulated kinase 1/2 (ERK1/2) activation, p38 mitogen-activated protein kinase (MAPK) activation and levels of proliferating cell nuclear antigen and α-smooth muscle actin compared with control animals. The vascular tissue Ang II level was higher in Ang-(1–7) and control rats than in sham animals. These findings suggest that Ang-(1–7) acts by inhibiting the activation of ERK1/2 and p38 MAPK in vascular tissue. The use of exogenous Ang-(1–7) could improve the outcome of vein grafting through the attenuation of vascular remodelling.

Denileukin diftitox in combination with rituximab for previously untreated follicular B-cell non-Hodgkin's lymphoma

Follicular lymphoma exhibits intratumoral infiltration by non-malignant T lymphocytes inluding CD4+CD25+ regulatory T (T_reg) cells. We combined denileukin diftitox with rituximab in previously untreated, advanced-stage follicular lymphoma patients anticipating that denileukin diftitox would deplete CD25+ T_reg cells while rituximab would deplete malignant B-cells. Patients received rituximab 375 mg/m2 weekly for 4 weeks and denileukin diftitox 18 mcg/kg/day for 5 days every 3 weeks for 4 cycles; neither agent was given as maintenance therapy. Between August 2008 and March 2010, 24 patients were enrolled. One patient died before treatment was given and was not included in the analysis. Eleven of 23 patients (48%; 95% CI: 27–69%) responded; 2 (9%) had complete responses and 9 (39%) had partial responses. The progression-free rate at 2 years was 55% (95%CI: 37–82%). Thirteen patients (57%) experienced grade ≥3 adverse events and 1 patient (4%) died. In correlative studies, soluble CD25 and the number of CD25+ T-cells decreased after treatment, however there was a compensatory increase in IL-15 and IP-10. We conclude that while the addition of denileukin diftitox to rituximab decreased the number of CD25+ T-cells, denileukin diftitox contributed to the toxicity of the combination without an improvement in response rate or time to progression.

Seroprevalence of hepatitis B virus markers in individuals for physical examination in West China Hospital, China

BACKGROUND

Hepatitis B virus (HBV) is the major cause of chronic hepatitis,cirrhosis, and hepatocellular carcinoma. The global epidemiological scenario of HBV infection has been changing rapidly over the last two decades due to an effective immunization programme initiated by the World Health Organization. The objective of this study is to estimate the prevalence of HBV in apparently adult people who were taken health examination in our Hospital.

METHODS

A cross-sectional seroprevalence analysis of hepatitis B virus infection was performed in 12037 adult residents (aged > or =18 years) in Chengdu, who visited Health Examination Center of West China Hospital of Sichuan University for routine medical check-up during the period from March to December 2008. A structured medical form was used to collect data on demographic characteristics and risk factors. ELISA was used to test sera for HBV markers. Descriptive and logistic regression models were used for analysis.

RESULTS

A total of 12,037 urban residents were involved. Prevalence of positive HBsAg was 6.1%, lower than the level of national seroepidemiological survey in (7.18%). Among HBsAg negative people, anti-HBs and anti-HBc was 60.2% and 13.6% respectively. There was a maximum between 18 to 29 years of age (61.8%) in anti-HBs positive people. Multivariate conditional logistic regressive analysis showed that, except for blood and vertical transmission, factors of male gender (OR, 1.876; 95% CI, 1.519-2.316; P < 0.001) and alcohol intake (OR, 0.689; 95% CI, 0.571-0.832; P < 0.001) were associated with a higher risk of positive HBsAg.

CONCLUSIONS

Among the medical examination people in Chengdu, HBsAg positive rate was lower than the national general population, the epidemiological characteristics of hepatitis B has been changed, because of vacination policies to the newborn; therefore, the necessity to continue to carry on the vaccination program.

Effect of liver X receptor activation on the very low density lipoprotein secretion and messenger ribonucleic acid level of related genes in goose primary hepatocytes

In this study, we investigated the role of liver X receptor (LXR) activation in hepatic assembly and in the secretion of very low density lipoprotein-triglycerides in goose primary hepatocytes. Goose primary hepatocytes were isolated and treated with the LXR agonist T0901317. Total triglyceride accumulation, intracellular and extracellular triglyceride concentrations, extracellular very low density lipoprotein concentration, and gene expression levels of LXRα, microsomal triglyceride transfer protein, acyl coenzyme A:diacylglycerol acyltransferase (DGAT) 1, and DGAT2 were measured in primary hepatocytes. We found a dose-dependent upregulation of total and intracellular TG accumulation when using 0, 0.01, 0.1, 1, and 10 μM T0901317, but the extracellular triglyceride and very low density lipoprotein concentrations were dose dependent only when the T0901317 concentration was below 1 μM; as compared with 1 μM T0901317, 10 μM T0901317 had an inhibiting effect (P < 0.05). The mRNA levels of all the detected genes increased in the presence of T0901317. The change in LXRα and DGAT1 was dose dependent, and the mRNA levels of microsomal triglyceride transfer protein and DGAT2 increased with a T0901317 concentration up to 1 μM, but decreased when treated with 10 μM T0901317 (P < 0.05). In conclusion, the secretion of very low density lipoprotein plays a role in pharmacologically activating the LXR-induced development of hepatocellular steatosis in geese.

Hybrid High-Temperature Nanostructured Magnets

The hysteretic behavior of two-phase permanent magnets for high-temperature applications is examined. A variety of systems have been synthesized and investigated, including Sm-Co-Cu-Ti bulk magnets, SmCo5:Cu-Ti thin-film materials, and mechanically milled Sm-CoZr magnets. The hybrid character of the material leads to very high room-temperature coercivities, between 30.2 and 43.6 kOe, and to the survival of a comparatively large part of the coercivity at high temperatures (12.3 kOe at 500 °C for SmCo 6.5Cu0.8Ti0.3). The coercivity reflects the structure and chemical composition of the material. When ferromagnetic grains are separated by a ferromagnetic boundary phase, the boundary phase acts as a pinning center, but when the grain-boundary phase has a comparatively low Curie temperature, the high-temperature magnetism of the system is that of a weakly interacting ensemble of magnetic particles. In spite of some residual paramagnetic exchange coupling, which is discussed in this work, this mechanism enhances the coercivity.