FGF signalling is involved in cumulus migration in the common house spider Parasteatoda tepidariorum.

Cell migration is a fundamental component during the development of most multicellular organisms. In the early spider embryo, the collective migration of signalling cells, known as the cumulus, is required to set the dorsoventral body axis. Here, we show that FGF signalling plays an important role during cumulus migration in the spider Parasteatoda tepidariorum. Spider embryos with reduced FGF signalling show reduced or absent cumulus migration and display dorsoventral patterning defects. Our study reveals that the transcription factor Ets4 regulates the expression of several FGF signalling components in the cumulus. In conjunction with a previous study, we show that the expression of fgf8 in the germ-disc is regulated via the Hedgehog signalling pathway. We also demonstrate that FGF signalling influences the BMP signalling pathway activity in the region around cumulus cells. Finally, we show that FGFR signalling might also influence cumulus migration in basally branching spiders and we propose that fgf8 might act as a chemo-attractant to guide cumulus cells towards the future dorsal pole of the spider embryo.

A Rapid, Sensitive, and High-throughput Method for the Simultaneous Determination of Antihypertensive Drug Combinations in Dog Plasma by UHPLC-MS/MS: The Assessment of Predicable Bioequivalence of In-vitro Dissolution Condition.

BACKGROUND: Essential hypertension is a common clinical disease and a risk factor for cardiovascular and cerebrovascular diseases. Olmesartan medoxomil, amlodipine, and hydrochlorothiazide are commonly used antihypertensive drugs. The aim of this study was to establish a robust UPLC-MS/MS method for the simultaneous determination of olmesartan medoxomil, amlodipine, and hydrochlorothiazide in dog plasma. At the same time, the release in vivo and in vitro studies were conducted, and a preliminary in vitro-in vivo correlation (IVIVC) evaluation was performed. METHODS: The bioequivalence experiment was conducted with a double-crossed design. Three major components were extracted and analyzed by UHPLC-MS/MS. With the MRM scan, olmesartan and amlodipine were quantified by fragment conversion (m/z 447.10→190.10) and (m/z 408.95→294.00) under positive ESI mode, while hydrochlorothiazide was quantified with fragment conversion (m/z 295.90→268.90) under negative ESI mode. The in vitro release studies were performed using a USP paddle, and the dissolution medium was chosen from pH 6.0 to pH 6.8 according to the BCS classification of compounds. The IVIVC was calculated using the Wagner-Nelson equation. RESULTS: The linear ranges of olmesartan, amlodipine, and hydrochlorothiazide in the plasma were 5.0-2500, 0.1-50, and 3.0-1500 ng/mL, respectively. All accuracies were within 3.8% of the target values, and the findings revealed that intra-day and inter-day accuracy was less than 12.1%. Moreover, the recoveries exceeded 88.3%, the matrix effect tests were positive, and the stability tests were positive. With the establishment of correlation, the distinguishable dissolution condition (pH 6.8) was selected as the predictable condition. CONCLUSION: The established method was suitable for the preclinical pharmacokinetic study of tripartite drugs with strong specificity and high sensitivity. Through the evaluation of IVIVC, the connection between in vivo and in vitro drug testing was initially established.

An atlas of spider development at single-cell resolution provides new insights into arthropod embryogenesis.

Spiders are a diverse order of chelicerates that diverged from other arthropods over 500 million years ago. Research on spider embryogenesis, particularly studies using the common house spider Parasteatoda tepidariorum, has made important contributions to understanding the evolution of animal development, including axis formation, segmentation, and patterning. However, we lack knowledge about the cells that build spider embryos, their gene expression profiles and fate. Single-cell transcriptomic analyses have been revolutionary in describing these complex landscapes of cellular genetics in a range of animals. Therefore, we carried out single-cell RNA sequencing of P. tepidariorum embryos at stages 7, 8 and 9, which encompass the establishment and patterning of the body plan, and initial differentiation of many tissues and organs. We identified 20 cell clusters, from 18.5 k cells, which were marked by many developmental toolkit genes, as well as a plethora of genes not previously investigated. We found differences in the cell cycle transcriptional signatures, suggestive of different proliferation dynamics, which related to distinctions between endodermal and some mesodermal clusters, compared with ectodermal clusters. We identified many Hox genes as markers of cell clusters, and Hox gene ohnologs were often present in different clusters. This provided additional evidence of sub- and/or neo-functionalisation of these important developmental genes after the whole genome duplication in an arachnopulmonate ancestor (spiders, scorpions, and related orders). We also examined the spatial expression of marker genes for each cluster to generate a comprehensive cell atlas of these embryonic stages. This revealed new insights into the cellular basis and genetic regulation of head patterning, hematopoiesis, limb development, gut development, and posterior segmentation. This atlas will serve as a platform for future analysis of spider cell specification and fate, and studying the evolution of these processes among animals at cellular resolution.

Simultaneous and trace level quantification of two potential genotoxic impurities in valsartan drug substance using UPLC-MS/MS.

A sensitive and selective Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method was developed for the identification and quantification of two potential genotoxic impurities (PGIs) - viz. methyl N-((2'-(1H-tetrazol-5-yl)-[1,1'-biphenyl]-4-yl)methyl)-N-nitroso-L-valinate (PGI-1) and N-nitroso Valsartan (PGI-2) - in the angiotensin II receptor blocker valsartan. Among these impurities, PGI-1 is a distinctive compound which has never been reported. For this, chromatographic separation was performed using a Waters XBridge BEH C18 column (150 mm × 4.6 mm, 2.5 µm), with ammonium acetate aqueous solution (0.01 mol/L) as mobile phase A and acetonitrile as mobile phase B, in a gradient elution mode at a 0.5 mL/min flow rate. Mass spectrometric conditions were optimized using electrospray ionization (ESI) in positive mode. Following the International Conference of Harmonization (ICH) guidelines, this methodology is capable of quantifying 2 PGIs at 0.016 ppm in samples at 50 mg/mL concentration. This validated approach presented good linearity over the concentration range of 0.016-0.06 ppm for 2 PGIs. The correlation coefficient of each impurity was observed greater than 0.999. The accuracy of this method was in the range of 83-113% for the aforementioned PGIs. In addition, expert knowledge rules (Derek-based) and statistical (Q) SAR evaluation system (Sarah-based) were used to evaluate and classify the genotoxicity of both valsartan-related PGIs as well as to define their standard limits. The predicted results were positive and classified into the third category, and the total nitrosamine limit was set to 0.03 ppm. As such, this approach represents a good quality control system for the simultaneous and precise quantitation of PGIs in valsartan.

Qualitative and quantitative assessment of related substances in the Compound Ketoconazole and Clobetasol Propionate Cream by HPLC-TOF-MS and HPLC.

Related substances in pharmaceutical formulations are associated with their safety, efficacy and stability. However, there is no overall study already published on the assessment of related substances in the Compound Ketoconazole and Clobetasol Propionate Cream. In this work, a reliable HPLC-TOF-MS qualitative method was developed for the analysis of related substances in this preparation with a quick and easy extraction procedure. Besides the active pharmaceutical ingredients, two compounds named ketoconazole impurity B' optical isomer and ketoconazole impurity E were identified. Furthermore, a new HPLC method for qualitative and quantitative assessment on related substances and degradation products, which were found in the stability test, was established and validated. The single standard to determine multi-components method was applied in the quantitative analysis, which was an effective way for reducing cost and improving accuracy. This study can provide a creative idea for routine analysis of quality control of the Compound Ketoconazole and Clobetasol Propionate Cream.

Protective effects of oleanolic acid on oxidative stress and the expression of cytokines and collagen by the AKT/NF­κB pathway in silicotic rats.

Oleanolic acid (OA), a natural pentacyclic triterpenoid, has been reported to have several benefits and medicinal properties. However, its protective effects against silica­induced lung injury and fibrosis remain to be elucidated. The aim of the present study was to investigate the effects of OA on oxidative stress, and the expression of cytokines and collagen in silicotic rats. Male rats were induced by intratracheal instillation of silicosis (250 mg/kg), with the exception of the control group (NS). The rats in the OA group were intragastrically administered with OA (60 mg/kg/d). The rats in the solvent control group were gavaged daily with 0.6% sodium carboxymethyl cellulose (10 ml/kg) solution for 56 consecutive days. The data showed that OA significantly attenuated the extent of silicosis fibrosis by histopathologic analysis of the lung tissues. In addition, oxidative stress activated by silica exposure, as evidenced by increasing of malondialdehyde content, and activities of superoxide dismutase and glutathione peroxidase in the lung, was regulated by treatment with OA. Furthermore, enzyme­linked immunosorbent assay analysis showed that OA significantly decreased the levels of tumor necrosis factor­α and transforming growth factor­ß1. Immunohistochemistry analysis showed that OA significantly decreased collagen types I and III. In investigating the mechanisms underlying the action of OA, it was found that OA decreased the level of phosphorylated AKT1, which in turn inactivated the transcriptional of nuclear factor (NF)­κB in the development and progress of silicosis. In conclusion, these results suggested that the protective effects of OA were due, at least in part, to its anti­oxidant activity and its ability to decrease the expression of cytokines and collagen by modulating the AKT/NF­κB pathway.