OBJECTIVE To establish a method for determining the contents of clopidogrel （CLP）， clopidogrel carboxylate （CLP-C）， clopidogrel acyl-β-D-glucuronide （CLP-G） and contents of clopidogrel active metabolite （CAM） in rat plasma， and to investigate their in vivo pharmacokinetic characteristics. METHODS The Shisedo CAPCELL ADME column was used with a mobile phase consisting of water and acetonitrile （both containing 0.1% formic acid） in a gradient elution. The flow rate was 0.4 mL/min， and the column temperature was maintained at 20 ℃. The injection volume was 2 μL. The analysis was performed in positive ion mode using electrospray ionization with multiple reaction monitoring. The ion pairs for quantitative analysis were m/z 322.1→211.9 （for CLP）， m/z 308.1→197.9 （for CLP-C）， m/z 322.1→154.8 （for CLP-G）， m/z 504.1→154.9 [for racemic CAM derivative （CAMD）]. Six rats were administered a single intragastric dose of CLP （10 mg/kg）. Blood samples were collected before medication and at 0.08， 0.33， 0.66， 1， 2， 4， 6， 10， 23 and 35 hours after medication. The established method was used to detect the serum contents of various components in rats. Pharmacokinetic parameters were then calculated using WinNonlin 6.1 software. RESULTS The linear ranges for CLP， CLP-C and CAMD were 0.08-20.00， 205.00-8 000.00， and 0.04-25.00 ng/mL， respectively （r≥0.990）. The relative standard deviations for both intra-day and inter-day precision tests were all less than 15%， and the relative errors for accuracy ranged from －11.68% to 14.40%. The coefficients of variation for the matrix factors were all less than 15%， meeting the requirements for bioanalytical method validation. The results of the pharmacokinetic study revealed that， following a single intagastric administration of CLP in rats， the exposure to the parent CLP in plasma was extremely low. Both the area under the drug concentration-time curve （AUC0-35 h） and the peak concentration of the parent CLP were lower than those of its metabolites. The AUC0-35 h of the active metabolite CAM was approximately 43 times that of CLP， though it had a shorter half-life （2.53 h）. The inactive metabolite CLP-C exhibited the highest exposure level， but it reached its peak concentration the latest and was eliminated slowly. The AUC0-35 h of CLP-G was about four times that of CAM， and its half-life was similar to that of CLP-C. CONCLUSIONS This study successfully established an liquid chromatography-tandem mass spectrometry method for the determination of CLP and its three metabolites， and revealed their pharmacokinetic characteristics in rats. Specifically， the parent drug CLP was rapidly eliminated， while the inactive metabolites CLP-C and CLP-G exhibited long half-lives， and active metabolite CAM displayed a transient exposure pattern.

Periodontitis is an inflammatory disease caused by bacterial infection directly, and the dysregulation of host immune-inflammatory response finally destroys periodontal tissues. Current treatment strategies for periodontitis mainly involve mechanical scaling/root planing (SRP), surgical procedures, and systemic or localized delivery of antimicrobial agents. However, SRP or surgical treatment alone has unsatisfactory long-term effects and is easy to relapse. In addition, the existing drugs for local periodontal therapy do not stay in the periodontal pocket long enough and have difficulties in maintaining a steady, effective concentration to obtain a therapeutic effect, and continuous administration always causes drug resistance. Many recent studies have shown that adding bio-functional materials and drug delivery systems upregulates the therapeutic effectiveness of periodontitis. This review focuses on the role of biomaterials in periodontitis treatment and presents an overview of antibacterial therapy, host modulatory therapy, periodontal regeneration, and multifunctional regulation of periodontitis therapy. Biomaterials provide advanced approaches for periodontal therapy, and it is foreseeable that further understanding and applications of biomaterials will promote the development of periodontal therapy.

OBJECTIVE To establish a method for simultaneous determination of atorvastatin （ATV） and its active metabolites 2-hydroxy atorvastatin acid （2-HAT）， 4-hydroxy atorvastatin acid （4-HAT） and toxic metabolite atorvastatin lactone （ALT） in rat plasma and apply it for pharmacokinetic study. METHODS LC-MS/MS method was adopted for analysis. The one-step precipitation method was used for processing plasma samples （plasma samples were pretreated by acidification to adjust pH value so as to prevent inversion of configuration）， gradient elution was used to analyze the samples， and the analysis time was 5 min. Electrospray positive ionization was adopted， and positive ion scanning was performed in multi-reaction monitoring. The m/z of quantified ion pairs of ATV and its metabolites such as 2-HAT， 4-HAT and ATL， and internal standard pitavastatin were 559.3→ 440.2， 575.2→440.3， 575.0→440.2， 540.9→448.2 and 422.2→290.0， respectively. After conducting a comprehensive methodological investigation of the analytical method， the concentrations of ATV and its metabolites 2-HAT， 4-HAT，and ATL were determined， and the pharmacokinetic parameters of ATV and its metabolites were calculated using the non- compartment model of WinNonlin 6.1. RESULTS The results of methodological validation showed that endogenous substances in blank plasma did not interfere with the determination of the components to be tested， and the standard curve had a good linear relationship； the lower limits of quantification for ATV， 2-HAT， 4-HAT and ATL were 0.5， 0.5， 0.25 and 0.063 nmol/L， respectively. The precision， accuracy， recovery， matrix effect and stability investigation were all in line with the requirements of biological analysis. Pharmacokinetic analysis showed that after intragastric administration in rats， ATV calcium metabolized rapidly， and was mainly exposed to blood circulation in the form of ATV and 2-HAT， with the lowest concentration of lactone-type metabolites. CONCLUSIONS The established method is precise， rapid and accurate for plasma concentration analysis of ATV and its active/toxic metabolites. The application of the method could help to fully elucidate the pharmacokinetic characteristics of atorvastatin calcium in rats.

Objective:To investigate the small and dense low density lipoprotein cholesterol (sdLDL-C) level, ratios of sdLDL-C/low density lipoprotein cholesterol (LDL-C), sdLDL-C/high density lipoprotein cholesterol (HDL-C) and sdLDL-C/apolipoprotein B (apoB), and their correlation with lipid components in healthy adults.Methods:A total of 1 151 healthy adults, who underwent physical examination in Beijing Anzhen Hospital Affiliated to Capital Medical University from September to December 2020 (557 men and 594 women), were included in this study. They were divided into five age groups: 18-29 years old ( n=247), 30-44 years old ( n=269), 45-59 years old ( n=225), 60-74 years old ( n=207) and 75-90 years old ( n=203) according to the age classification standard of the United Nations World Health Organization in 2018. The levels of total cholesterol (TC), triglyceride (TG), HDL-C, LDL-C, sdLDL-C, apoA1 and apoB were measured, and the distribution of sdLDL-C, sdLDL-C/LDL-C, sdLDL-C/HDL-C and sdLDL-C/apoB in different sex and age groups were analyzed. Pearson/Spearman correlation was used to analyze the correlation between the above four indexes and other blood lipid components. Results:SdLDL-C, sdLDL-C/LDL-C, sdLDL-C/HDL-C and sdLDL-C/apoB were higher in male group ([0.56±0.23] mmol/L, 0.24±0.07, 0.49±0.22, 0.27±0.07) than those in female group ([0.48±0.18] mmol/L, 0.20±0.06, 0.36±0.17, 0.23±0.07) (all P<0.01). SdLDL-C, sdLDL-C/LDL-C, sdLDL-C/HDL-C and sdLDL-C/apoB were different among different age groups of male and female participants (all P<0.001). SdLDL-C level was significantly higher in males than in females among 18-29 years old group, 30-44 years old group, 45-59 years old group (all P<0.05). SdLDL-C, sdLDL-C/LDL-C, sdLDL-C/HDL-C and sdLDL-C/apoB were higher in males of 18-29 years old group, 30-44 years old group, 45-59 years old group and 60-74 years old group than in females of corresponding age groups (all P<0.05). The level of sdLDL-C of all participants was positively correlated with TC, TG, LDL-C, apoB, non-HDL-C and remnant cholesterol ( r＝0.50, 0.45, 0.67, 0.68, 0.61, 0.11, all P<0.01), and negatively correlated with HDL-C and apoA1 ( r＝-0.17 and -0.10, P<0.01). Conclusions:The levels of sdLDL-C, sdLDL-C/LDL-C, sdLDL-C/HDL-C and sdLDL-C/apoB in healthy adults are different in healthy adults of different ages and sex. There is a high correlation between sdLDL-C and apoB.

Traumatic spinal cord injury (TSCI) is a common nerve injury in the world, which has a high incidence and disability rate. Intraspinal pressure (ISP) monitoring is performed by placing a pressure sensing probe under the dura of the most severe part of the spinal cord injury after anterior/posterior laminectomy or vertebral body decompression. ISP value is monitored dynamically and objectively in real time by the pressure sensing system. Recent studies have found that ISP monitoring plays an important role in the clinical management and prognosis evaluation of TSCI. The author reviews the recent advance in ISP monitoring in TSCI in order to provide references for the improvement of clinical diagnosis and treatment of TSCI.

Traumatic spinal cord injury (TSCI) is a common nerve injury in the world, which has a high incidence and disability rate. Intraspinal pressure (ISP) monitoring is performed by placing a pressure sensing probe under the dura of the most severe part of the spinal cord injury after anterior/posterior laminectomy or vertebral body decompression. ISP value is monitored dynamically and objectively in real time by the pressure sensing system. Recent studies have found that ISP monitoring plays an important role in the clinical management and prognosis evaluation of TSCI. The author reviews the recent advance in ISP monitoring in TSCI in order to provide references for the improvement of clinical diagnosis and treatment of TSCI.

Objective:To study the correlation between liver imaging reporting and data system (LI-RADS) category with tumor differentiation, Ki67 index, microvascular infiltration, and predictive prognosis in hepatocellular carcinoma (HCC).Methods:We retrospectively analyzed the clinical and radiological data of 178 patients with HCC who were confirmed by histopathological studies after liver resection between January 2015 and September 2020 at Lishui Central Hospital and Lishui People’s Hospital. There were 156 males and 22 females, with age of (57±10) years old. These patients were assessed for LI-RADS categories according to the 2018 version of LI-RADS, and they were divided into 4 groups according to the assessment results: 12 patients with LI-RADS-3 (the LI-RADS-3 group); 26 patients with LI-RADS-4 (the LI-RADS-4 group); 102 patients with LI-RADS-5 (the LI-RADS-5 group); and 38 patients with LI-RADS-M (the LI-RADS-M group). The patients' general information, tumor markers, pathology and other clinical data were recorded. Correlation analysis between the LI-RADS category with pathology was performed by the Kendall's tau-b test. Survival analysis between groups was performed by the Kaplan-Meier analysis. The Cox regression risk model was used to analyze the relationship between these variables with the risk of death.Results:The Kendall's tau-b test showed that LI-RADS category was positively correlated with the degree of tumor differentiation ( t=0.204, P=0.002), but not with microvascular infiltration and Ki 67 index ( P>0.05). All patients were followed up for 4.2 to 84.2 months (median follow-up 36.3 months). By the end of follow-up, 31 patients had died and 147 patients were alive. The cumulative 1-year and 3-year survival rates of the LI-RADS-5 group were 97% and 90% respectively, which were significantly higher than those in the LI-RADS-M group (81% and 63%), and the LI-RADS-4 group (96% and 81%), ( P<0.05). The cumulative 1-year and 3-year survival rates of patients in the LI-RADS-3 group were 100% and 67% respectively, and there was no statistically significant difference with the LI-RADS-5 group ( P>0.05). The Cox multivariate regression analysis showed that tumor glycoantigen 199 (>50 μl/ml) to be an independent influencing factor in survival of HCC patients ( HR=0.43, 95% CI: 0.24-0.76, P=0.004). Conclusion:The LI-RADS category of HCC was positively correlated with the degree of tumor differentiation, and patients with HCC meeting the LI-RADS-5 criteria had relatively better prognosis.

Once pulp necrosis or apical periodontitis occurs on immature teeth, the weak root and open root apex are challenging to clinicians. Berberine (BBR) is a potential medicine for bone disorders, therefore, we proposed to apply BBR in root canals to enhance root repair in immature teeth. An in vivo model of immature teeth with apical periodontitis was established in rats, and root canals were filled with BBR, calcium hydroxide or sterilized saline for 3 weeks. The shape of the roots was analyzed by micro-computed tomography and histological staining. In vitro, BBR was introduced into stem cells from apical papilla (SCAPs). Osteogenic differentiation of stem cells from apical papilla was investigated by alkaline phosphatase activity, mineralization ability, and gene expression of osteogenic makers. The signaling pathway, which regulated the osteogenesis of SCAPs was evaluated by quantitative real time PCR, Western blot analysis, and immunofluorescence. In rats treated with BBR, more tissue was formed, with longer roots, thicker root walls, and smaller apex diameters. In addition, we found that BBR promoted SCAPs osteogenesis in a time-dependent and concentration-dependent manner. BBR induced the expression of β-catenin and enhanced β-catenin entering into the nucleus, to up-regulate more runt-related nuclear factor 2 downstream. BBR enhanced root repair in immature teeth with apical periodontitis by activating the canonical Wnt/β-catenin pathway in SCAPs.
Animals ; Berberine ; pharmacology ; Cell Differentiation ; drug effects ; Dental Papilla ; Male ; Osteogenesis ; drug effects ; Periapical Periodontitis ; therapy ; Rats ; Stem Cells ; cytology ; drug effects ; metabolism ; Wnt Signaling Pathway ; drug effects ; Wnt3A Protein ; genetics ; metabolism ; X-Ray Microtomography

Homoeostasis depends on the close connection and intimate molecular exchange between extracellular, intracellular and intercellular networks. Intercellular communication is largely mediated by gap junctions (GJs), a type of specialized membrane contact composed of variable number of channels that enable direct communication between cells by allowing small molecules to pass directly into the cytoplasm of neighbouring cells. Although considerable evidence indicates that gap junctions contribute to the functions of many organs, such as the bone, intestine, kidney, heart, brain and nerve, less is known about their role in oral development and disease. In this review, the current progress in understanding the background of connexins and the functions of gap junctions in oral development and diseases is discussed. The homoeostasis of tooth and periodontal tissues, normal tooth and maxillofacial development, saliva secretion and the integrity of the oral mucosa depend on the proper function of gap junctions. Knowledge of this pattern of cell-cell communication is required for a better understanding of oral diseases. With the ever-increasing understanding of connexins in oral diseases, therapeutic strategies could be developed to target these membrane channels in various oral diseases and maxillofacial dysplasia.
Bone and Bones ; Cell Communication ; Connexins ; metabolism ; physiology ; Gap Junctions ; metabolism ; pathology ; Homeostasis ; physiology ; Humans ; Mouth Diseases ; Phosphorylation

Bone remodelling keeps going through the lifespan of human by bone formation and bone resorption. In the craniofacial region, mandibles act as the main force for biting and chewing, and also become susceptible to a common bone-loss disease, namely, apical periodontitis, once infected dental pulp is not treated timely, during which bone resorption occurs from the apical foramen to the apical bone area. Although conventional root canal treatment (RCT) can remove the most of the infection, chronical apical periodontitis due to incomplete removal of dental pulp and subsequent microleakage will become refractory and more challenging, and this process has scarcely been specifically studied as a bone remodelling issue in rat models. Therefore, to study chronical and refractory apical periodontitis owing to incomplete cleaning of infected dental pulp and microleackage in vivo, we establish a modified rat model of gradually progressive apical periodontitis by sealing residual necrotic dental pulp and introducing limited saliva, which simulates gradually progressive apical periodontitis, as observed in the clinical treatment of chronical and refractory apical periodontitis. We show that bone-loss is inevitable and progressive in this case of apical periodontitis, which confirms again that complete and sound root canal treatment is crucial to halt the progression of chronical and refractory apical periodontitis and promote bone formation. Interestingly, bone remodelling was enhanced at the initial stage of apical periodontitis in this model while reduced with a high osteoblast number afterwards, as shown by the time course study of the modified model. Suggesting that the pathological apical microenvironment reserve its hard tissue formation ability to some degree but in a disturbed manner. Hopefully, our findings can provide insights for future bone regenerative treatment for apical periodontitis-associated bone loss.