Design, synthesis, and biological evaluation of a series of bifunctional ligands of opioids/SSRIs

A series of opioid and serotonin re-uptake inhibitors (SSRIs) bifunctional ligands have been designed, synthesized, and tested for their activities and efficacies at μ-, δ- and κ opioid receptors and SSRIs receptors. Most of the compounds showed high affinities for μ- and δ-opioid receptors and lower affinities for SSRIs and κ opioid receptors. A docking study on the μ-opioid receptor binding pocket has been carried out for ligands 3-11. The ligands 7 and 11 have displayed the highest binding profiles for the μ-opioid receptor binding site with ΔGbind (-12.14kcal/mol) and Ki value (1.0nM), and ΔGbind (-12.41kcal/mol) and Ki value (0.4nM), respectively. Ligand 3 was shown to have the potential of dual acting serotonin/norepinephrine re-uptake inhibitor (SNRI) antidepressant activity in addition to opioid activities, and thus could be used for the design of multifunctional ligands in the area of a novel approach for the treatment of pain and depression.

Modification of amphipathic non-opioid dynorphin A analogues for rat brain bradykinin receptors

It has been shown that under chronic pain or nerve injury conditions, up-regulated dynorphin A (Dyn A) interacts with bradykinin receptors (BRs) to cause hyperalgesia in the spinal cord. Thus BRs antagonist can modulate hyperalgesia by blocking Dyn A's interaction with the BRs in the central nervous system. In our earlier structure-activity relationship (SAR) study, [des-Arg(7)]-Dyn A-(4-11) 13 was discovered as a minimum pharmacophore for rat brain BRs with its antagonist activity (anti-hyperalgesic effect) in in vivo tests using naïve or injured animals. We have pursued further modification on the [des-Arg(7)]-Dyn A analogues and identified a key insight into the pharmacophore of the rat brain BRs: amphipathicity.

Synthesis and biological evaluation of compact, conformationally constrained bifunctional opioid agonist - neurokinin-1 antagonist peptidomimetics

A reported mixed opioid agonist - neurokinin 1 receptor (NK1R) antagonist 4 (Dmt-D-Arg-Aba-Gly-(3',5'-(CF3)2)NMe-benzyl) was modified to identify important features in both pharmacophores. The new dual ligands were tested in vitro and subsequently two compounds (lead structure 4 and one of the new analogues 22, Dmt-D-Arg-Aba-β-Ala-NMe-Bn) were selected for in vivo behavioural assays, which were conducted in acute (tail-flick) and neuropathic pain models (cold plate and von Frey) in rats. Compared to the parent opioid compound 33 (without NK1R pharmacophore), hybrid 22 was more active in the neuropathic pain models. Attenuation of neuropathic pain emerged from NK1R antagonism as demonstrated by the pure NK1R antagonist 6. Surprisingly, despite a lower in vitro activity at NK1R in comparison with 4, compound 22 was more active in the neuropathic pain models. Although potent analgesic effects were observed for 4 and 22, upon chronic administration, both manifested a tolerance profile similar to that of morphine and cross tolerance with morphine in a neuropathic pain model in rat.

Clinical and laboratory characteristics of systemic sclerosis patients with pulmonary arterial hypertension in China

OBJECTIVES

Pulmonary arterial hypertension (PAH) is associated with significant morbidity and mortality, especially in systemic sclerosis (SSc). Since there was no published study regarding PAH in the Chinese SSc population, we aimed to describe a cohort to provide some data for early diagnosis.

METHODS

We evaluated 236 systemic sclerosis patients prospectively registered in the EUSTAR (European League Against Rheumatism Scleroderma Trial and Research Group) database from the Peking Union Medical College Hospital from 2009 to 2012. Among them, 33 individuals received right heart catheterisations (RHC) while the remaining patients were grouped by echocardiographic data. These patients were classified into two groups, PAH and non-PAH group. Their clinical and laboratory features were statistically analysed to identify possible risk factors for PAH in Chinese SSc population.

RESULTS

The possible prevalence of PAH in SSc patients was approximately 11% in our study. Digital ulcers (52.0% vs. 31.2%), telangiectasias (64.0% vs. 37.6%) and gastroesophageal reflux disease (GERD) (60.0% vs. 36.2%) were more common in SSc patients with PAH. Some laboratory results were also proved to be significantly correlated with it. Logistic regression analysis showed that telangiectasias (OR=2.888, 95% CI=1.176-7.093), presence of GERD (OR=2.592, 95% CI=1.067-6.296), anti-RNP positivity (OR=24.384, 95% CI=1.978-36.651), IgA level elevation (OR=8.745, 95% CI 4.838-122.896) and FVC/TLCO ratio (OR=97.067, 95% CI 12.475-755.271) were associated with an increased odds for PAH in SSc patients.

CONCLUSIONS

This study described possible predictors of PAH in Chinese SSc population, which have been supported by similar studies in other ethnic groups.

Structure-activity relationships of non-opioid [des-Arg(7)]-dynorphin A analogues for bradykinin receptors

In our earlier studies, bradykinin receptors (BRs) were identified as a potential target for the neuroexcitatory effects of dynorphin A (Dyn A) in the central nervous system (CNS), and [des-Arg(7)]-Dyn A-(4-11) (6) was discovered as a lead ligand to modulate Dyn A-(2-13) induced neuroexcitatory effects in the CNS as an antagonist. In an effort to gain insights into key structural features of the Dyn A for the BRs, we pursued further structure-activity relationships (SAR) study on the [des-Arg(7)]-Dyn A analogs and confirmed that all of the [des-Arg(7)]-Dyn A analogues showed good binding affinities at the BRs.

Variability in free 25(OH) vitamin D levels in clinical populations

Our goal was to determine total and directly measured free 25-hydroxy vitamin D (25(OH)D) serum levels in humans with a range of 25(OH)D levels and clinical conditions associated with low and high vitamin D binding protein levels. Serum samples and clinical data were collected from 106 subjects: 62 without cirrhosis or pregnancy, 24 cirrhotic patients with albumin <2.9g/dL, and 20 pregnant women. Total 25(OH)D (LC/MS/MS) and "free" 25(OH)D (immunoassay) were measured. Total 25(OH)D was significantly lower in liver disease patients but free 25(OH)D concentrations were significantly higher in this group (p<.001). Neither total nor free 25(OH)D concentrations were significantly different in pregnant women vs. the comparator group. There were significant direct positive relationships between free 25(OH)D and total 25(OH)D concentrations for the entire dataset and for each group (p<.0001), however slopes of relationships differed in the cirrhotic group compared to pregnant women or the comparator group. In cirrhotics: y (free 25(OH)D)=2.52+0.29×X(total 25 (OH)D), r(2)=.51, p<.001; y=1.45+0.09×X; r(2)=.77, p<.0001 for pregnant women; and y=1.11+0.12×X; r(2)=.72, p<.0001 for the comparator group).

CONCLUSIONS

directly measured free 25(OH)D serum concentrations and relationships between total and free 25(OH)D vary with clinical conditions, and may differ from those predicted by indirect estimation methods. This article is part of a Special Issue entitled 'Vitamin D Workshop'.

Neuropathic plasticity in the opioid and non-opioid actions of dynorphin A fragments and their interactions with bradykinin B2 receptors on neuronal activity in the rat spinal cord

Dynorphin A is an endogenous opioid peptide derived from the precursor prodynorphin. The proteolytic fragment dynorphin A (1-17) exhibits inhibitory effects via opioid receptors. Paradoxically, the activity of the dynorphin system increases with chronic pain and neuropathy is associated with the up-regulation of dynorphin biosynthesis. Dynorphin A (1-17) is cleaved in vivo to produce a non-opioid fragment, dynorphin A (2-17). Previously, a mechanism by which the non-opioid fragment promotes pain through agonist action at bradykinin receptors was revealed. Bradykinin receptor expression is up-regulated after nerve injury and both a truncated version of non-opioid fragment dynorphin A (2-17), referred to as 'Ligand 10', and novel bradykinin receptor antagonist 'Ligand 14', are known to bind to the bradykinin receptor. Here we show that Ligand 10 facilitates the response of wide dynamic range (WDR) neurons to innocuous and noxious mechanical stimuli in neuropathic, but not naïve, animals, while Ligand 14 exhibits inhibitory effects in neuropathic animals only. Furthermore, we reveal an inhibitory effect of Ligand 14 in naïve animals by pre-dosing with either Ligand 10 or a 5-HT3 receptor agonist to reflect activation of descending excitatory drives. Thus remarkably, by mimicking pro-excitatory pharmacological changes that occur after nerve injury in a naïve animal, we induce a state whereby the inhibitory actions of Ligand 14 are now effective. Ultimately our data support an increasing number of studies that suggest that blocking spinal bradykinin receptors may have a therapeutic potential in chronic pain states, here, in particular, in neuropathic pain.

Measurements of fusion reactions of low-intensity radioactive carbon beams on 12C and their implications for the understanding of X-ray bursts

The interaction between neutron-rich nuclei plays an important role for understanding the reaction mechanism of the fusion process as well as for the energy production through pycnonuclear reactions in the crust of neutron stars. We have performed the first measurements of the total fusion cross sections in the systems (10,14,15)C+(12)C using a new active target-detector system. In the energy region accessible with existing radioactive beams, a good agreement between the experimental and theoretical cross sections is observed. This gives confidence in our ability to calculate fusion cross sections for systems which are outside the range of today's radioactive beam facilities.

Discovery of amphipathic dynorphin A analogues to inhibit the neuroexcitatory effects of dynorphin A through bradykinin receptors in the spinal cord

We hypothesized that under chronic pain conditions, up-regulated dynorphin A (Dyn A) interacts with bradykinin receptors (BRs) in the spinal cord to promote hyperalgesia through an excitatory effect, which is opposite to the well-known inhibitory effect of opioid receptors. Considering the structural dissimilarity between Dyn A and endogenous BR ligands, bradykinin (BK) and kallidin (KD), this interaction could not be predicted, but it allowed us to discover a potential neuroexcitatory target. Well-known BR ligands, BK, [des-Arg(10), Leu(9)]-kallidin (DALKD), and HOE140 showed different binding profiles at rat brain BRs than that previously reported. These results suggest that neuronal BRs in the rat central nervous system (CNS) may be pharmacologically distinct from those previously defined in non-neuronal tissues. Systematic structure-activity relationship (SAR) study at the rat brain BRs was performed, and as a result, a new key structural feature of Dyn A for BR recognition was identified: amphipathicity. NMR studies of two lead ligands, Dyn A-(4-11) 7 and [des-Arg(7)]-Dyn A-(4-11) 14, which showed the same high binding affinity, confirmed that the Arg residue in position 7, which is known to be crucial for Dyn A's biological activity, is not necessary, and that a type I β-turn structure at the C-terminal part of both ligands plays an important role in retaining good binding affinities at the BRs. Our lead ligand 14 blocked Dyn A-(2-13) 10-induced hyperalgesic effects and motor impairment in in vivo assays using naïve rats. In a model of peripheral neuropathy, intrathecal (i.th.) administration of ligand 14 reversed thermal hyperalgesia and mechanical hypersensitivity in a dose-dependent manner in nerve-injured rats. Thus, ligand 14 may inhibit abnormal pain states by blocking the neuroexcitatory effects of enhanced levels of Dyn A, which are likely to be mediated by BRs in the spinal cord.

A comparison of measured and calculated free 25(OH) vitamin D levels in clinical populations

OBJECTIVE

Our goal was to compare direct quantitation of circulating free 25-hydroxyvitamin D (25(OH)D)levels to calculated free 25(OH)D levels and their relationships to intact PTH (iPTH), a biomarker of 25(OH)D effect, in humans with a range of clinical conditions.

PATIENTS AND METHODS

Serum samples and clinical data were collected from 155 people: 111 without cirrhosis or pregnancy (comparison group), 24 cirrhotic patients with albumin <2.9 g/dL, and 20 pregnant women (second and third trimester). Total 25(OH)D (LC/MS/MS), free 25(OH)D (immunoassay), vitamin D binding protein (DBP) (immunoassay), albumin, and iPTH (immunoassay) were measured.

RESULTS

Total 25(OH)D, DBP, and albumin were lowest in patients with cirrhosis, but measured free 25(OH)D was highest in this group (P < .001). DBP was highest in pregnant women (P < .001), but measured free 25(OH)D did not differ from the comparison group. Calculated free 25(OH)D was positively correlated with measured free 25(OH)D (P < .0001) but explained only 13% of the variability with calculated values higher than measured. African Americans had lower DBP than other ethnic populations within all clinical groups (P < .03), and differences between measured and calculated free 25(OH)D were greatest in African Americans (P < .001). Measured free 25(OH)D was correlated with total 25(OH)D (P < .0001; r(2) = 0.51), but calculated free 25(OH)D was not. Similarly, both measured free 25(OH)D (P < .02) and total 25(OH)D (P < .05) were correlated with iPTH, but calculated free 25(OH)D was not.

CONCLUSIONS

Calculated free 25(OH)D levels varied considerably from direct measurements of free 25(OH)D with discrepancies greatest in the data for African Americans. Differences in DBP binding affinity likely contributed to estimation errors between the races. Directly measured free 25(OH)D concentrations were related to iPTH, but calculated estimates were not. Current algorithms to calculate free 25(OH)D may not be accurate. Further evaluation of directly measured free 25(OH)D levels to determine its role in research and clinical management of patients is needed.

Noise temperature improvement for magnetic fusion plasma millimeter wave imaging systems

Significant progress has been made in the imaging and visualization of magnetohydrodynamic and microturbulence phenomena in magnetic fusion plasmas [B. Tobias et al., Plasma Fusion Res. 6, 2106042 (2011)]. Of particular importance have been microwave electron cyclotron emission imaging and microwave imaging reflectometry systems for imaging T(e) and n(e) fluctuations. These instruments have employed heterodyne receiver arrays with Schottky diode mixer elements directly connected to individual antennas. Consequently, the noise temperature has been strongly determined by the conversion loss with typical noise temperatures of ~60,000 K. However, this can be significantly improved by making use of recent advances in Monolithic Microwave Integrated Circuit chip low noise amplifiers to insert a pre-amplifier in front of the Schottky diode mixer element. In a proof-of-principle design at V-Band (50-75 GHz), significant improvement of noise temperature from the current 60,000 K to measured 4000 K has been obtained.

Covalent amphiphilic polyoxometalates for the design of biphasic microemulsion systems

Unprecedented stabilization of a Winsor I microemulsion has been achieved using a covalent polyoxotungstate amphiphile.

Gene expression signature analysis and protein-protein interaction network construction of spinal cord injury

BACKGROUND

The aim of this study was to investigate the gene expression profile of thoracic propriospinal neurons between post-injury rat and controls.

MATERIALS AND METHODS

Microarray dataset GSE20907 was downloaded from GEO database, including 12 Spinal Cord Injury (SCI) rat and 12 controls. Student's t test was employed to identified differentially expressed genes with a fold-change > 1.2. Then, we used DAVID to perform functional enrichment analysis to uncover dysfunctional biological processes and molecular signatures database (MsigDB) to find any potential relationship between SCI gene expression signature and other published gene expression signature. Protein-Protein interaction (PPI) network was constructed by STRING and visualized in Cytoscape. Functional analysis of the hub protein was performed by BinGO.

RESULTS

The maximum change of gene expression profile was found at 3-days post injury and immune response was found upregulated all tested time points. Interestingly, genes upregulated 2-weeks post injury was found significantly overlapped with genes upregulated in brains from Alzheimer's disease patients. Protein interaction network analysis found that LYN, PTPN6 and SMAD1 could be of great value for further investigation.

CONCLUSIONS

It could be inferred that understanding the underlying molecular mechanism post injury, especially at early moment, may provide novel insight for development of therapeutics strategy.

Vulval cancer incidence, mortality and survival in England: age-related trends

OBJECTIVE

To explore the trends and age characteristics of vulval cancer incidence, mortality, survival and stage of disease.

DESIGN

Retrospective population-based observational study based on cancer registry and Office for National Statistics data.

SETTING

England.

POPULATION

All women diagnosed with vulval cancer, defined by the site of the tumour (ICD-10 code C51).

METHODS

Including all C51 cases, Poisson regression was used to test for trends in incidence and mortality rates, and generalised linear modelling was used to test for trends in relative survival. Excluding women with melanomas, basal cell carcinomas and Paget disease, stage was investigated as a percentage of staged data by age.

MAIN OUTCOME MEASURES

Age-standardised incidence and mortality rates, relative survival rates and stage of disease at diagnosis.

RESULTS

From 1990, there was a statistically significant increase in overall incidence (P = 0.018) and decrease in mortality (P < 0.001). In addition, there were statistically significant increases in overall survival (1-year, P < 0.001; 5-year, P < 0.001). However, from 1990, incidence increased in women aged 20-39 years (P = 0.002), 40-49 and 50-59 years (both P < 0.001) and 60-69 years (P = 0.030) and decreased in women aged 80 years and above (P < 0.001). There were statistically significant decreases in mortality in women aged ≥60 years (P < 0.001), and statistically significant increases in 1-year survival in women aged ≥40 years (P ≤ 0.047) and in 5-year survival in women aged 40-49 and ≥60 years (P ≤ 0.011). Stage patterns by age highlight diagnosis at an earlier stage in younger women and more advanced stage diagnosis in older women.

CONCLUSION

Survival from vulval cancer has improved and mortality has decreased since 1990. The overall incidence of disease has increased as a result of more new diagnoses in the under 70-year age group.

Dietary patterns as compared with physical activity in relation to metabolic syndrome among Chinese adults

AIMS

To examine the nationally-representative dietary patterns and their joint effects with physical activity on the likelihood of metabolic syndrome (MS) among 20,827 Chinese adults.

METHODS AND RESULTS

CNNHS was a nationally representative cross-sectional observational study. Metabolic syndrome was defined according to the Joint Interim Statement definition. The "Green Water" dietary pattern, characterized by high intakes of rice and vegetables and moderate intakes in animal foods was related to the lowest prevalence of MS (15.9%). Compared to the "Green Water" dietary pattern, the "Yellow Earth" dietary pattern, characterized by high intakes of refined cereal products, tubers, cooking salt and salted vegetable was associated with a significantly elevated odds of MS (odds ratio 1.66, 95%CI: 1.40-1.96), after adjustment of age, sex, socioeconomic status and lifestyle factors. The "Western/new affluence" dietary pattern characterized by higher consumption of beef/lamb, fruit, eggs, poultry and seafood also significantly associated with MS (odds ratio: 1.37, 95%CI: 1.13-1.67). Physical activity showed significant interactions with the dietary patterns in relation to MS risk (P for interaction = 0.008). In the joint analysis, participants with the combination of sedentary activity with the "Yellow Earth" dietary pattern or the "Western/new affluence" dietary pattern both had more than three times (95%CI: 2.8-6.1) higher odds of MS than those with active activity and the "Green Water" dietary pattern.

CONCLUSIONS

Our findings from the large Chinese national representative data indicate that dietary patterns affect the likelihood of MS. Combining healthy dietary pattern with active lifestyle may benefit more in prevention of MS.

Chiral Effect of a Phe Residue in Position 3 of the Dmt1-L(or D)-Tic2 Analogues on Opioid Functional Activities

In this letter, we describe a structure-activity relationships study, specifically related to the chirality of third amino acid residue in our H-Dmt-L(or D)-Tic analogues, of which C-terminus is attached to a piperidinyl moiety. Observed selectivities and functional activities of these analogues demonstrated that the chiralities of the second and third position residues are crucial for determining whether these ligands act as antagonists or agonists at the δ opioid receptor, but not at the μ opioid receptor.

Biological active analogues of the opioid peptide biphalin: mixed α/β(3)-peptides

Natural residues of the dimeric opioid peptide Biphalin were replaced by the corresponding homo-β(3) amino acids. The derivative 1 containing hβ(3) Phe in place of Phe showed good μ- and δ-receptor affinities (Ki(δ) = 0.72 nM; Ki(μ) = 1.1 nM) and antinociceptive activity in vivo together with an increased enzymatic stability in human plasma.