The class B G-protein-coupled GLP-1 receptor: an important target for the treatment of type-2 diabetes mellitus

Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone secreted from L cells in the distal small intestine and proximal colon after a meal that acts as an incretin to augment the insulin response, while also inhibiting glucagon and slowing gastric emptying. These characteristics of GLP-1, as well as its ability to reduce islet beta cell apoptosis and expand beta cell mass and its cardioprotective and neuroprotective effects, provide a broad spectrum of actions potentially useful for the management of type-2 diabetes mellitus. GLP-1 also has the added advantage of having its incretin effects dependent on the level of serum glucose, only acting in the presence of hyperglycaemia, and thereby preventing hypoglycemic responses. Although natural GLP-1 has a very short half-life, limiting its therapeutic usefulness, a variety of analogues and formulations have been developed to provide extended actions and to limit side effects. However, all of these peptides require parenteral administration. Potentially orally active small-molecule agonists acting at the GLP-1 receptor are also being developed, but have not yet been approved for clinical use. Recent insights into the molecular nature of the class B G-protein-coupled GLP-1 receptor has provided insights into the modes of binding these types of ligands, as well as providing opportunities for rational enhancement. The advantages and disadvantages of each of these agents and their possible clinical utility will be explored.

Photoprotection in the green tidal alga Ulva prolifera: role of LHCSR and PsbS proteins in response to high light stress

Ulva prolifera, an intertidal macroalga, has to adapt to wide variations in light intensity, making this species particularly rewarding for studying the evolution of photoprotective mechanisms. Intense light induced increased non-photochemical quenching (NPQ) and stimulated de-epoxidation of xanthophyll cycle components, while DTT-treated samples had lower NPQ capacity, indicating that the xanthophyll cycle must participate in photoprotection. In this work, we found that the PsbS-related NPQ was maintained in U. prolifera. According to analysed gene expression, both LhcSR and psbS were up-regulated in high light, suggesting that these two genes are light-induced. LHCSR and PsbS proteins were present at different light intensities and accumulated under high light conditions, and PsbS concentrations were higher than LHCSR, showing that the NPQ mechanism of U. prolifera is more dependent on PsbS protein concentration. Moreover, the level of both LHCSR and PsbS proteins was high even in the darkness, and neither the transcript level nor protein content of LhcSR and psbS genes varied significantly following short-term exposure to intense light. These findings suggest that this alga can modulate NPQ levels through regulation of the xanthophyll cycle and concentrations of PsbS and/or LHCSR.

Receptor activity-modifying protein-dependent impairment of calcitonin receptor splice variant Δ(1-47)hCT((a)) function

BACKGROUND AND PURPOSE

Alternative splicing expands proteome diversity to GPCRs. Distinct receptor variants have been identified for a secretin family GPCR, the calcitonin receptor (CTR). The possible functional contributions of these receptor variants are further altered by their potential interactions with receptor activity-modifying proteins (RAMPs). One variant of the human CTR lacks the first 47 residues at its N terminus [Δ(1-47)hCT((a)) ]. However, very little is known about the pharmacology of this variant or its ability to interact with RAMPs to form amylin receptors.

EXPERIMENTAL APPROACH

Δ(1-47)hCT((a)) was characterized both with and without RAMPs in Cos7 and/or HEK293S cells. The receptor expression (ELISA assays) and function (cAMP and pERK1/2 assays) for up to six agonists and two antagonists were determined.

KEY RESULTS

Despite lacking 47 residues at the N terminus, Δ(1-47)hCT((a)) was still able to express at the cell surface, but displayed a generalized reduction in peptide potency. Δ(1-47)hCT((a)) retained its ability to interact with RAMP1 and formed a functional amylin receptor; this also appeared to be the case with RAMP3. On the other hand, its interaction with RAMP2 and resultant amylin receptor was reduced to a greater extent.

CONCLUSIONS AND IMPLICATIONS

Δ(1-47)hCT((a)) acts as a functional receptor at the cell surface. It exhibits altered receptor function, depending on whether it associates with a RAMP and which RAMP it interacts with. Therefore, the presence of this variant in tissues will potentially contribute to altered peptide binding and signalling, depending on the RAMP distribution in tissues.

Estimation of birth population-based perinatal-neonatal mortality and preterm rate in China from a regional survey in 2010

Objective:

To estimate birth population-based perinatal-neonatal mortality and preterm rate in China from a regional survey in 2010.

Study design:

Data of total births in 2010 obtained from 151 level I–III hospitals in Huai’an, Jiangsu, were prospectively collected and analyzed.

Results:

From 61 227 birth registries (including 60 986 live births and 241 stillbirths), we derive a birth rate of 11.3‰ (of 5.4 million regional population), a male-to-female ratio of 116:100 and valid data from 60 615 newborns. Mean birth weight (BW) was 3441 ± 491 g with 13.6% macrosomia. Low BW was 2.8% (1691/60 372) with 8.83% mortality. Preterm rate was 3.72% (2239/60 264) with 7.61% mortality. Cesarean section rate was 52.9% (31 964/60 445), multiple pregnancy 1.8% (1088/60 567) and birth defects 6.7‰ (411/61 227). There were 97.4% healthy newborns and 2.2% (1298) requiring hospitalized after birth. The perinatal mortality was 7.7‰ (471/61 227, including 241 stillbirths, 230 early neonatal deaths). The neonatal mortality was 4.4‰ (269/60 986). The main causes of neonatal death were birth asphyxia (24.5%), respiratory diseases (21.5%), prematurity related organ dysfunction (18.5%) and congenital anomalies (7.7%), whereas incidence of congenital heart disease and respiratory distress syndrome was 8.6‰ and 6.1‰, respectively.

Conclusions:

This regional birth population-based data file contains low perinatal-neonatal mortality rates, associated with low proportion of LBW and preterm births, and incidences of major neonatal disease, by which we estimate, in a nationwide perspective, in 16 million annual births, preterm births should be around 800 000, perinatal and neonatal mortality may be 128 000–144 000 and 80 000–96 000, respectively, along with 100 000 respiratory distress syndrome.

Degradation of nitenpyram pesticide in aqueous solution by low-temperature plasma

In order to study the new technique of plasma wastewater treatment, the degradation behaviour ofnitenpyram (NTP) pesticide was investigated in a low-temperature plasma formed during a dielectric barrier discharge process. The reactor was a radial flow sedimentation tank centred around the water inlet. We studied the effect of pesticide concentration and input power of the dielectric barrier discharge, together with the effect of external factors on the degradation of nitenpyram pesticide wastewater such as conductivity and the use of various of catalysts, and the reaction products were analyzed by high-performance liquid chromatography mass spectrometry (HPLC-MS). The results showed that NTP could be effectively removed from aqueous solution by low-temperature plasma. Increasing the input power could improve the efficiency of degradation, conforming to a first-order kinetic model. Use of a suitable catalyst clearly improved the degradation process, as also did low conductivity. The pH of NTP was reduced with discharge time.

Acute pancreas allograft rejection is associated with increased risk of graft failure in pancreas transplantation

The effect of acute allograft rejection (AR) on long-term pancreas allograft function is unclear. We retrospectively studied 227 consecutive pancreas transplants performed at our institution between January 1, 998 and December 31, 2009 including: 56 simultaneous pancreas and kidney (SPK), 69 pancreas transplantation alone (PTA); and 102 pancreas after kidney (PAK) transplants. With a median follow-up of 6.1 (IQR 3-9) years, 57 patients developed 79 episodes of AR, and 19 experienced more than one episode. The cumulative incidence for AR was 14.7%, 19.7%, 26.6% and 29.1% at 1, 2, 5 and 10 years. PTA transplant (hazards ratio [HR]=2.28, p=0.001) and donor age (per 10 years) (HR=1.34, p=0.006) were associated with higher risk for AR. The first AR episode after 3 months post PT was associated with increased risk for complete loss (CL) (HR 3.79, p<0.001), and the first AR episode occurring during 3- to 12-month and 12- to 24-month periods after PT were associated with significantly increased risk for at least partial loss (PL) (HR 2.84, p=0.014; and HR 6.25, p<0.001, respectively). We conclude that AR is associated with increased risk for CL and at least PL. The time that the first AR is observed may influence subsequent graft failure.

Detrimental effects of endogenous oestrogens on primary acute myocardial infarction among postmenopausal women

OBJECTIVE

Traditionally, oestrogens were considered to be protective for the cardiovascular system for premenopausal women. Therefore, we conducted a retrospective case-control study to examine the association between endogenous oestrogens and acute myocardial infarction (AMI) risk among postmenopausal women.

METHODS

A case-control study was performed among 30 primary AMI patients and 60 control subjects. Baseline characteristics data was collected and endogenous sex hormones levels were determined using chemoluminescence and radioimmunoassay methods. Conditional logistic regression models were developed with adjustment for confounders.

RESULTS

Compared with controls, the circulating oestrone, oestradiol, androstenedione and testosterone levels were significantly higher in AMI patients (P < 0.05) while the sex hormone binding globulin (SHBG) level was lower (P < 0.05). Spearman correlation coefficients showed oestradiol was positively correlated with body mass index (BMI) and waist-to-hip ratio (WHR) in cases, but not in controls. In univariable conditional logistic regression models, oestrone, oestradiol, testosterone, WHR, BMI, diabetes and hypertension were all found to be positively associated with AMI (P < 0.05). After adjusting for these factors, oestradiol (odds ratio (OR) = 4.75; 95 % confidence interval (CI) = 1.07-21.10; P = 0.04) and WHR (OR = 6.46; 95 % CI = 1.09-38.39; P = 0.04) continued to demonstrate strong positive associations with AMI.

CONCLUSIONS

A higher level of oestradiol was potentially associated with primary AMI risk among postmenopausal women.

Bisoprolol improved endothelial function and myocardium survival of hypertension with stable angina: a randomized double-blinded trial

AIM

This study was designed to determine the effect of bisoprolol on endothelial function of brachial artery and the myocardium survival in hypertensive patients with stable angina.

PATIENTS AND METHODS

222 subjects with hypertension who had received coronary angiography examination were involved in the study, 162 in bisoprolol therapy group (96 men, 59%) and 60 in non-bisoprolol group (39 men, 65%). In accordance with results of angiography (coronary stenosis ≥ 50%), the patients in bisoprolol group were divided into three sub-groups: (1) single-vessel coronary disease group (n=42); (2) double-vessel coronary disease group (n=44); (3) multi-vessel coronary disease group (n=39) and hypertension-only group (n=37). All the subjects were treated with conventional drugs plus bisoprolol and followed up for 12 months. Parameters of clinical features, echocardiography, radionuclide ventriculographic and laboratory findings were measured and analyzed.

RESULTS

After 12 months bisoprolol treatment, the flow-mediated vasodilatation (FMD) and 99Tcm-sestamibi (99Tcm-MIBI) uptake fraction which reflects the survival of myocardium were improved markedly in bisoprolol group (all p < 0.05). Interestingly, a more significant improvement in FMD and 99Tcm-MIBI uptake fraction were observed in severe coronary disease sub-groups (double-vessel group and multi-vessel group) when compared with single-vessel sub-group (p < 0.05).

CONCLUSIONS

Hypertensive subjects with stable angina might get benefit from the treatment of bisoprolol in improving endothelial function and the survival of myocardium.

Autologous dendritic cells combined with cytokine-induced killer cells synergize low-dose chemotherapy in elderly patients with acute myeloid leukaemia

OBJECTIVES

To investigate the possibility of culturing dendritic cells (DCs) and cytokine-induced killer (CIK) cells, obtained at initial diagnosis of AML in elderly patients, and to investigate the safety and efficacy of treatment with autologous DCs and CIK cells when administered to these patients in combination with low-dose chemo therapy.

METHODS

DCs and CIK cells obtained at initial diagnosis of AML in elderly patients were cultured and used in combination with low-dose chemo therapy to treat these patients (immunotherapy group). Elderly patients with AML treated only with low-dose chemotherapy served as the control. Before treatment and on day 7 after treatment with autologous DCs and CIK cells, T cell subsets and cytokine levels were evaluated in the immunotherapy group.

RESULTS

A total of 21 elderly patients with AML were included in the immunotherapy group and 23 in the control group. The clinical efficacy in the immunotherapy group was greater than in the control group. The percentages of T cell subsets and cytokine levels after immunotherapy treatment were significantly higher than before the treatment.

CONCLUSION

Immuno therapy with autologous DCs and CIK cells was found to be a promising candidate for treatment of AML in elderly patients.

Interactive effects of mechanical stress, sand burial and defoliation on growth and mechanical properties in Cynanchum komarovii

In drylands, wind, sand burial and grazing are three important factors affecting growth and mechanical properties of plants, but their interactive effects have not yet been investigated. Plants of the semi-shrub Cynanchum komarovii, common in semi-arid parts of NE Asia, were subjected to brushing, burial and defoliation. We measured biomass allocation and relative increment rates of dry mass (RGR(m)), height (RGR(h)) and basal diameter (RGR(d)). We also measured the stem mechanical properties, Young's modulus (E), second moment of area (I), flexural stiffness (EI) and breaking stress (σ(b)), and scaled these traits to the whole-plant level to determine the maximum lateral force (F(lateral)) and the buckling safety factor (BSF). Brushing increased RGR(m); neither burial nor defoliation independently affected RGR(m), but together they reduced it. Among buried plants, brushing positively affected stem rigidity and strength through increasing RGR(d), E, I and EI, and at whole plant level this resulted in a larger BSF and F(lateral). However, among unburied plants this pattern was not observed. Our results thus show that effects of mechanical stress and grazing on plants can be strongly modified by burial, and these interactions should be taken into account when considering adaptive significance of plant mechanical traits in drylands.

Protective effect of puerarin against beta-amyloid-induced oxidative stress in neuronal cultures from rat hippocampus: involvement of the GSK-3β/Nrf2 signaling pathway

Current evidence suggests that amyloid beta (Aβ) peptides may play a major role in the pathogenesis of Alzheimer's disease in part by eliciting oxidative stress. Puerarin, a major isoflavone glycoside from Kudzu root (Pueraria lobata), has been reported to exert estrogen-like and antioxidant activities. The central hypothesis guiding this study is that puerarin will prevent or at least markedly attenuate Aβ(25-35)-induced excess production of reactive oxygen species (ROS) by interrupting glycogen synthase kinase-3β (GSK-3β) signaling. In this study, we demonstrate that pretreatment of primary hippocampal neurons with puerarin significantly reduced Aβ(25-35)-induced oxidative stress characterized by scavenging of ROS and inhibiting lipid peroxidation. Puerarin induced expression of nuclear Nrf2 protein, but not in the Nrf2 mRNA level, and increased heme oxygenase-1 (HO-1) levels at levels of transcription and translation. Puerarin-induced Serine 9 phosphorylation of GSK-3β was blocked by lithium chloride treatment in primary hippocampal neurons, indicating the participation of the GSK-3β inactivation. This protective effect was partially reversed when GSK-3β were blocked by the chemical inhibitors such as lithium chloride. These results suggest puerarin as a phytoestrogen with potential of a possible therapeutic agent in neurodegenerative diseases involving oxidative stress.

Cellular and physiological mechanisms of new-onset diabetes mellitus after solid organ transplantation

New-onset diabetes after transplantation is recognized as one of the metabolic consequences which may increase the risk of morbidity and mortality after solid organ transplantation. The pathophysiology of new-onset diabetes after transplantation has not been clearly defined and may resemble that of Type 2 diabetes, characterized by predominantly insulin resistance or defective insulin secretion, or both. This review aims to summarize the current state of knowledge regarding the prevalence, consequences, pathogenesis, and management of new-onset diabetes after transplantation, with a major focus on the possible mechanisms involved in the pathogenesis of the disorder. The aetiology of new-onset diabetes after transplantation is multifactorial, with diabetogenic immunosuppressive drugs playing a major role. Multiple cellular and physiologic mechanisms are involved in the process. Selection of an appropriate maintenance immunosuppressive regimen should involve balancing the risk of patient and graft survival vs. the potential for new-onset diabetes after transplantation.

Pulmonary delivery and tissue distribution of aerosolized antisense 2'-O-Methyl RNA containing nanoplexes in the isolated perfused and ventilated rat lung

Pulmonary delivery of drugs, particularly in the treatment of lung cancer, is an attractive strategy for future targeted therapy. In this context, inhalation of nanoplexes might offer a new mode for drug delivery in gene therapy. However, limited data are currently available demonstrating pulmonary delivery, cellular uptake as well as local tolerability in lung tissue. The aim of this study was to elucidate the pulmonary delivery, tissue distribution and local tolerability of aerosolized chitosan-coated poly(lactide-co-glycolide) based nanoplexes containing antisense 2'-O-Methyl RNA (OMR). Therefore, an aerosol of OMR-nanoplexes or OMR alone was administered intra-tracheally using the model of the isolated perfused and ventilated rat lung. Localization of OMR in rat lung tissue was examined by immunohistochemistry. Administration of the OMR-nanoplex formulation resulted in significantly higher cellular OMR uptake of the respiratory epithelium in contrast to the administration of OMR alone, indicating that drug administration via aerosolized nanoplexes is able to target lung tissue. No prominent changes in lung physiology parameters were observed following inhalation, suggesting good local tolerability of OMR-nanoplex formulation.

Treatment of lung cancer via telomerase inhibition: self-assembled nanoplexes versus polymeric nanoparticles as vectors for 2'-O-Methyl-RNA

Antisense oligonucleotide, 2'-O-Methyl-RNA (OMR), is known as potent telomerase inhibitor for the treatment of lung cancer but limited by poor intracellular uptake. Chitosan-coated polymeric nanoparticles were compared to chitosan solution as non-viral vectors for OMR. The study investigated the role of chitosan properties and concentration in improving the efficiency of the nanocarriers in terms of loading, viability, cellular uptake, and telomerase inhibition in human lung cancer cell lines. Certain concentration of chitosan on nanoparticle surface is necessary to significantly increase the cellular uptake. However, excessive chitosan negatively affected the transfection efficiency. Self-assembled nanoplexes with chitosan polymer are preferentially adsorbed to the cell membrane rather than being internalized. Thus, polymeric nanoparticles proved to be superior to cationic polymers as carrier for antisense oligonucleotides. Charge cannot be considered the principle factor behind improved transfection. Uptake studies carried out on air-interface cell cultures to mimic in vivo conditions supported the results on normal cultures showing enhanced uptake of nanoplexes over naked oligonucleotides. OMR nanoplexes reduced telomerase activity by ∼50% in A549 cells concluding the potential of the system as a safe, non-invasive, and efficient treatment for lung carcinoma. These data are prerequisites for the ongoing studies on lung perfusion model and in vivo experiments.

Interindividual reaction time variability is related to resting-state network topology: an electroencephalogram study

Both anatomical and functional brain network studies have drawn great attention recently. Previous studies have suggested the significant impacts of brain network topology on cognitive function. However, the relationship between non-task-related resting-state functional brain network topology and overall efficiency of sensorimotor processing has not been well identified. In the present study, we investigated the relationship between non-task-related resting-state functional brain network topology and reaction time (RT) in a Go/Nogo task using an electroencephalogram (EEG). After estimating the functional connectivity between each pair of electrodes, graph analysis was applied to characterize the network topology. Two fundamental measures, clustering coefficient (functional segregation) and characteristic path length (functional integration), as well as "small-world-ness" (the ratio between the clustering coefficient and characteristic path length) were calculated in five frequency bands. Then, the correlations between the network measures and RT were evaluated in each band separately. The present results showed that increased overall functional connectivity in alpha and gamma frequency bands was correlated with a longer RT. Furthermore, shorter RT was correlated with a shorter characteristic path length in the gamma band. This result suggested that human RTs were likely to be related to the efficiency of the brain integrating information across distributed brain regions. The results also showed that a longer RT was related to an increased gamma clustering coefficient and decreased small-world-ness. These results provided further evidence of the association between the resting-state functional brain network and cognitive function.

Exploring serological classification tree model of active pulmonary tuberculosis by magnetic beads pretreatment and MALDI-TOF MS analysis

Pulmonary tuberculosis (TB) is an infectious disease disturbing status of public health, and accurate diagnosis of TB would effectively help control the disturbance. Our study tried to establish a classification tree model that distinguished active TB from non-TB individuals. We used matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) combined with weak cationic exchange (WCX) magnetic beads to analyse 178 serum samples containing 75 patients with active TB and 103 non-TB individuals (43 patients with common pulmonary diseases and 60 healthy controls). Samples were randomly divided into a training set and a test set. Statistical softwares were applied to construct this model. An amount of 48 differential expressed peaks (P < 0.05) were identified by the training set, and our model was set up by three of them, m/z 7626, 8561 and 8608. This model can discriminate patients with active TB from patients with non-TB with a sensitivity of 98.3% and a specificity of 84.4%. The test set was used to verify the performance, which demonstrated good sensitivity and specificity: 85.7% and 83.3%, respectively. Differential expressed peaks between smear-positive and smear-negative active TB also have been analysed. It came out that m/z 8561 and 8608 not only acted as vital factors in the pathogenesis of active TB but also played an important role in regulating different active TB status. In conclusion, MALDI-TOF MS combined with WCX magnetic beads was a powerful technology for constructing classification tree model, and the model we built could serve as a potential diagnostic tool for active TB.