[Geochemical Background and Baseline Value of Soil Chemical Elements in Hebei Province].

Geochemical background and baseline values are important parameters for understanding the geochemical characteristics of soil elements, but the research degree of these two parameters is lacking in Hebei Province. Therefore, data from the multi-purpose regional geochemical survey and land quality geochemical assessment in Hebei Province from 2004 to 2018 were collected, covering approximately 71% of the land area of the whole province. Based on the data of surface soil and deep soil, scientific and robust methods including median value and median absolute deviation were used to calculate the geochemical background values, geochemical baseline values, as well as variation ranges of 54 indexes (Ag, Al2O3, As, Au, B, Ba, Be, Bi, Br, CaO, Cd, Ce, Cl, Co, Cr, Cu, F, Fe2O3, Ga, Ge, Hg, I, K2O, La, Li, MgO, Mn, Mo, N, Na2O, Nb, Ni, P, Pb, pH, Rb, S, Sb, Sc, Se, SiO2, Sn, Sr, Th, Ti, Tl, U, V, W, Y, Zn, Zr, total carbon (TC), and organic carbon (Corg)) in Hebei Province and 11 prefecture-level cities. The change rate in geochemical background for each index was also calculated. The results showed that the geochemical background and baseline values of most soil chemical elements in Hebei Province were lower than those nationwide, but the values of Ba, Br, Cl, MgO, Na2O, P, pH, S, Sr, and TC were higher, with CaO being the highest. Compared with those in north China, there was no significant difference in the geochemical background and baseline values for the 54 indexes, with the ratios of 0.83-1.17 and 0.79-1.19, respectively. Significant changes in the geochemical background for Corg, Hg, N, P, S, and Se were observed in Hebei Province, indicating that these indexes were greatly influenced by human factors. Preliminary analysis suggests that coal burning emissions and agricultural chemical use were two very important inducing factors.

Sigma ligands as potent inhibitors of Aß and AßOs in neurons and promising therapeutic agents of Alzheimer's disease.

Alzheimer's disease (AD) is an age-related neurodegenerative disease and characterized by dementia, memory decline, loss of learning and cognitive disorder. The main pathological features of AD are the deposition of amyloid plaques and the formation of neurofibrillary tangles (NFTs) in the brain. The current anti-AD drugs have shown unsatisfactory therapeutic results. Due to the complications and unclear pathogenesis, AD is still irreversible and incurable. Among several hypotheses proposed by the academic community, the amyloid cascade is widely recognized by scholars and supported by a large amount of evidences. However, controversy over pathogenic factors has also been ongoing. Increasing evidence has shown that amyloid-ß (Aß) and especially amyloid-ß oligomers (AßOs) are highly neurotoxic and pathogenic agents that damage neurons, mediate various receptors in the downstream pathways, and ultimately lead to learning and cognitive dysfunction. However, efforts in developing inhibitors of Aß or amyloid-ß precursor protein (APP) have all failed to yield good clinical results. More recently, it has been demonstrated that sigma receptors, including sigma-1 and sigma-2 subtypes, may play critical roles in the regulation of binding and metabolism of AßOs in neuron cells and the pathophysiology of AD. Thus, sigma receptor ligands are being recognized as promising therapeutic agents for treating or ameliorating AD. This article will review the pathophysiology of AD and highlight the sigma ligands that display the capability of preventing or even reversing Aß- and AßOs-induced neurotoxicity and blocking the signal transduction caused by AßOs.

Sigma-2 Receptor as a Potential Drug Target.

Sigma-2 receptor plays key roles in promoting tumor cell apoptosis, enhancing efficacy of anti-tumor drugs, blocking signal transduction controlled by Aß oligomers, regulating Ca2+ homeostasis and protecting nerve cells. Studies indicated that sigma-2 receptor may be closely coupled with ROS, LDL, mTOR, RAS, PLC/PKC, lysosomal autophagy and mitochondrial super oxidative stress. In addition, the high expression of this receptor in proliferating cells and nerve cells indicates that sigma-2 receptor is an ideal molecular target for imaging and therapeutic development for cancer, Alzheimer's disease, schizophrenia and traumatic brain injury. Various sigma-2 agonists have shown promising anticancer activities, while sigma-2 antagonists have displayed neuroprotection and inhibition of Aß oligomers in the brain of Alzheimer's disease patients. Thus, both sigma-2 agonists and antagonists are potentially useful therapeutics for the management of cancer and neurodegenerative disorders.

Synthesis, binding, and functional properties of tetrahydroisoquinolino-2-alkyl phenones as selective σ2R/TMEM97 ligands.

Sigma-2 receptor (σ2R/TMEM97) has been implicated to play important roles in multiple cellular dysfunctions, such as cell neoplastic proliferation, neuro-inflammation, neurodegeneration, etc. Selective σ2 ligands are believed to be promising pharmacological tools to regulate or diagnose various disorders. As an ongoing effort of discovery of new and selective σ2 ligands, we have synthesized a series of tetrahydroisoquinolino-2-alkyl phenone analogs and identified that 10 of them have moderate to potent affinity and selectivity for σ2R/TMEM97. Especially, 4 analogs showed Ki values ranging from 0.38 to 5.1 nM for σ2R/TMEM97 with no or low affinity for sigma-1 receptor (σ1R). Functional assays indicated that these 4 most potent analogs had no effects on intracellular calcium concentration and were classified as putative σ2R/TMEM97 antagonists according to current understanding. The σ2R/TMEM97 has been suggested to play important roles in the central nervous system. Based on published pharmacological and clinical results from several regarded σ2R/TMEM97 antagonists, these analogs may potentially be useful for the treatment of various neurodegenerative diseases.

Synthesis and evaluation of pyrimidoindole analogs in umbilical cord blood ex vivo expansion.

The scarcity of hematopoietic stem cells (HSCs) significantly hindered their clinical potentials. Umbilical cord blood (UCB) has become the leading source of HSCs for both research and clinical applications. But the low content of HSCs in a single UCB unit limited its use only to pediatric patients. Various cytokines and small molecules have demonstrated strong abilities in promoting HSC ex vivo expansion, of which UM171 is the newest and by far the most potent HSC ex vivo expansion agent. In this study, we synthesized 37 pyrimidoindole analogs and identified 6 compounds to be potent in promoting HSC ex vivo expansion. In particular, analog 11 was found to be the most effective in stimulating ex vivo expansion of UCB CD34+ cells and CD34+CD38- cells. Initial data indicated that compound 11 promoted the absolute number of long term HSCs and inhibited their differentiation. UCB HSCs expanded with 11 retained adequate multi-lineage differentiation capacity. In addition, compound 11 is not cytotoxic at its test concentrations, suggesting that it merits further investigation for potential clinical applications.

Isolation, synthesis, and cytotoxicity evaluation of two impurities in nomegestrol acetate.

Nomegestrol acetate (NOMAc) is a synthetic progesterone analog and classified as a fourth-generation progestin. It has been approved in many countries for oral contraception, hormonal replacement therapy (HRT), and treatment of various gynecological disorders. There are several synthetic routes reported for the synthesis of NOMAc and they all share the very similar last three to five steps toward the conversion of 6-methylene to 6-methyl-6,7-unsaturated structure. Therefore the final product from different processing routes may have similar impurity profiles. In the analysis of NOMAc, we identified two impurities, impurity A (listed in EP 8.0) and impurity B (not specified in EP 8.0). Both impurities were further confirmed by synthesis. In addition, both impurities and NOMAc were evaluated for their in vitro cytotoxicities against L02 liver cells, mesenchymal stem cells, MCF-7 breast cancer cells, and C33A cervical cancer cells. These three analogs are not cytotoxic to the four cell lines at low concentrations (<20 µM). NOMAc and impurity A showed cytotoxicity to L02, MCF-7, and C33A cells at high concentrations, while impurity B did not show significant cytotoxicity to any of the cell lines tested.

Synthesis and pharmacological evaluation of 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline derivatives as sigma-2 receptor ligands.

Increasing evidences have implicated that sigma-2 receptor is a biomarker and significantly over-expressed in many proliferative cancer cells with no or low expression in normal cells. Sigma-2 receptor selective ligands have been successfully used as valuable tools to study its pharmacological functions, tumor imaging, and cancer therapeutics or adjuvants. 6,7-Dimethoxy-1,2,3,4-tetrahydroisoquinolinylalkyl benzamides are among a few categories of structures that have demonstrated high affinities and selectivities for sigma-2 receptor and been used extensively as study tools in various tumor imaging and therapy. As a continuous effort, we have synthesized a new series of 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline derivatives and evaluated their affinities for both sigma-1 and sigma-2 receptors. Most of these newly developed analogs showed good to excellent binding affinities for sigma-2 receptor with no or low affinities for sigma-1 receptor. In particular, compounds 3b, 3e, 4b, and 4e demonstrated Ki values of 5-6 nM affinities and excellent selectivities for sigma-2 receptor. In addition, these analogs also demonstrated moderate anticancer activities against human liver Huh-7 tumor cells and human esophagus KYSE-140 cancer cells. But their cytotoxicities seem not to be correlated with their sigma-2 receptor affinities.