To establish a sensitive and specific LC-MS/MS method for determination of the binding conditions of ponicidin with bovine serum albumin (BSA) and analysis of its mechanism. The protein binding rates and related binding constants of ponicidin in BSA samples were determined by ultrafiltration and LC-MS/MS. Scatchard equation was used to calculate the binding constant (Ka) of ponicidin in BSA samples as well as the number of binding sites (n), and the mechanism on ponicidin binding with BSA was explored. The results showed that the average protein binding rate of ponicidin with BSA was 57.2%, mainly as grade Ⅰ intensive binding, and the relevant binding constant was 2.54×104 L•μg⁻¹, with a binding site number of n=0.75. The binding of ponicidin with BSA had no concentration dependence within the investigated concentrations. The established method in this study showed high sensitivity, specificity, simple operation and met the analysis requirements, and the calculation of binding constant laid foundation for the clinical drug interactions and pharmacokinetics research.

To determine the absorption properties and study the intestinal absorption kinetics of poncidin in rats. In situ single pass perfusion model was combined with High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS/MS) method to investigate the intestinal absorption characteristics and calculate absorption parameters with aspects of drug absorption, concentration and perfusion medium. The absorption of poncidin under acid condition at pH 6.5 was more stable, where intestinal enzymes showed little influence on metabolism, and the absorption was significantly higher than that in pH alkaline condition at pH 8.0 (<0.05). Drug concentrations had no significant influence on absorption rate constant of the same intestinal segment Ka and apparent permeability coefficient Papp values of poncidin. Different concentrations of poncidin showed no significant differences in the Ka and Papp values among duodenum, jejunum and colon, but the values were significantly lower than ileum absorption parameters, with significant differences (<0.05). There was no significant effect of verapamil on intestinal absorption of poncidin. The results showed that poncidin could be absorbed at all the studied intestinal segments while ileum seemed to be the best absorption segment in the concentration range of 10-1 000 μg·L⁻¹. The absorption was characterized by a linear dynamic process of passive transport, without absorption saturation. Weak acid environment was helpful for the intestinal absorption of poncidin, and ponicidin was not a substrate of P-glycoprotein (P-gp).

OBJECTIVETo investigate the effects of alveolar bone resorption on stress of tooth/implant-supported restoration connected by precision attachment using three-dimensional finite element(FEM) approach.

METHODSThe FEM was applied to analyze the stress distribution of tooth/implant-supported restoration connected by precision attachment under various loading conditions when the alveolar bone was absorbed to different level.

RESULTSThe stress values of the tooth, implant and their surrounding bone increased when their surrounding bone decreased by bone absorption.

CONCLUSIONThe stress values of the tooth, implant and their surrounding bone were closely related with the bone resorption.

Alveolar Process ; Bone Resorption ; Bone and Bones ; Dental Prosthesis, Implant-Supported ; Dental Stress Analysis ; Finite Element Analysis ; Humans

Objective To optimize clinical dosage regimen of sparfloxa-cin through series of pharmacokinetic/pharmacodynamic ( PK/PD ) val-ues.Methods The minimum inhibitory concentration ( MIC ) of spar-floxacin to 479 isolated bacteria were measured by two -fold agar dilution method.To perform pharmacokinetic test after those healthy volunteers were given a single oral dose of 0.1 , 0.2 , 0.3 g of Sparfloxacin , respec-tively.Based on PK/PD theory, calculation of AUC0-24 h/MIC values af-ter three dosages were done.Estimated value of AUC 0-24 h/MIC≥125 was expected to be the target value ( for streptococcus pneumoniae AUC0-24 h/MIC≥50).The Monte Carlo simulation was repeated 1 ×104 times, and the cumulative fraction of response ( CFR) value was calculat-ed according to the respective probability distributions and different AUC0-24 h/MIC and MIC values.The dosage achieving a CFR above 90 percent was recognized as the optimal dosage regimen.Results Given dose of 0.1 g, the pharmacodynamics value CFR was above 90%only to salmonella genera.Given dose of 0.2 g, the pharmacodynamics value CFR was above 90%to Nitrate negative bacillus, Streptococcus pneumoni-ae, Acinetobacter and Methicillin -sensitive Staphylococcus aureus (MSSA).For other strains, oral dose of 0.3 g was needed to not only achieve satisfactory clinical curative effect but also effectively prevent the drug resistance.And for infections caused by Methicillin -resistant Staphylococcus aureus (MRSA), enhanced drug dose should be considered to achieve satisfactory clinical efficacy.Conclusion For infection caused by salmonella genera, oral dose of 0.1 g was a appropriate dosage regimen.For infection caused by Nitrate negative bacillus, Strepto-coccus pneumoniae, Acinetobacter and MSSA, oral dose of 0.2 g was a proper dosage regimen.For infection caused by others, oral dosage regimen of 0.3 g could achieve the expected satisfactory clinical efficacy.And for infections caused by MRSA, an increasing dosage , such as 0.4 mg, could achieve satisfactory clinical curative effect.

BACKGROUNDTransforming growth factor β (TGFβ) is one of the most important growth factors in the development of fibrosis and scarring on cornea. Smad7, an inhibitory Smad, can inhibit TGFβ signal transduction. In recent years, effects of lentiviral-mediated Smad7 on inhibition of fibrosis on some organs have been studied, while little is known about the effects on cornea. This study aimed to determine the effects of lentiviral-mediated Smad7 gene expression on keratocyte proliferation and fibrosis induced by TGF β2 in vitro.

METHODSKeratocytes were cultured from corneal tissue isolated from Sprague-Dawley (SD) rats and transfected with Smad7 expressing lentiviral vector (Lv-Smad7) or non-functioning control vector (Lv-blank). Following the exposure to TGFβ2, keratocytes were processed for immunoblotting to assess the phosphorylation of Smad2 as down-stream event of TGFβ/Smad signaling. Expression of fibrotic markers α-smooth muscle actin (α-SMA), type III collagen (collagen III) were measured by Western blotting and quantitative real time polymerase chain reaction (PCR). Overall cell proliferation was determined by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the expression of cell cycle-related marker Ki67 at both mRNA and protein levels.

RESULTSThe Smad7 gene transfer suppressed TGFβ/Smad signaling in keratocytes by down-regulating phosphorylation of Smad2. Markers of cell proliferation and fibrosis including Ki67, α-SMA, collagen III were inhibited by introduction of Smad 7 into TGFβ exposed keratocytes. Consequently, the rate of cell proliferation was attenuated.

CONCLUSIONSmad7 gene transfer inhibited fibrogenic responses of keratocytes to TGFβ2.

Actins ; genetics ; metabolism ; Animals ; Blotting, Western ; Cell Proliferation ; Cells, Cultured ; Collagen Type III ; genetics ; metabolism ; Corneal Keratocytes ; cytology ; drug effects ; metabolism ; Genetic Vectors ; genetics ; Ki-67 Antigen ; genetics ; metabolism ; Lentivirus ; genetics ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects ; genetics ; Smad7 Protein ; genetics ; metabolism ; pharmacology ; Transforming Growth Factor beta2 ; pharmacology

BACKGROUNDHaze or corneal subepithelial fibrosis is one of the common complications after refractive surgery procedures, such as photorefractive keratectomy (PRK), laser epithelial keratomileusis, and epipolis laser in situ keratomileusis, which would result in refractive regression, decreased visual quality, and corneal opacification. Haze directly resulted from corneal fibrosis mediated by transforming growth factor β (TGFβ). Smad7, an inhibitory Smad, can inhibit TGFβ signal transduction. Recently, the effects of Smad7 on the inhibition of fibrosis in several organs have been studied, while little is known about the effects on cornea after PRK. This study was aimed to determine the effects of lentiviral-mediated Smad7 gene expression on corneal fibrosis in rats after PRK.

METHODSFour different experimental groups were established using right eyes of Sprague-Dawley rats. Thirty-two eyes underwent de-epithelialization only and served as a sham operation group (group 1). Ninety-six eyes underwent PRK operation and were further divided into group 2 (the PRK group) without lentivector administration, group 3 (the Lv-blank group) with control lentiviral vector without Smad7 administration, and group 4 (the Lv-Smad7 group) with Smad7 expressing lentiviral vector Smad7 administration. At 1 day, 1 week, 1 month, and 3 months after PRK, the transfection efficiency was determined by measuring the fluorescence signal as well as Smad7 protein and mRNA levels. Corneas were further processed for immunoblotting to assess the phosphorylation of Smad2 as a downstream event of TGFβ/Smad signaling. The expression of fibrotic markers, such as α-smooth muscle actin (α-SMA), Type III collagen (collagen III), and cell cycle-related marker Ki67, was measured by quantitative real-time reverse transcription polymerase chain reaction (RT-PCR).

RESULTSLentivirus-mediated exogenous Smad7 gene expression in rat corneal tissue resulted in reduced activation of TGFβ/Smad signaling caused by downregulation of phosphorylation of Smad2. Smad7 also downregulated the expression of TGFβ2. Markers of cell proliferation and fibrosis, including Ki67, α-SMA, and collagen III, were inhibited by Smad7 up to 3 months after PRK operation.

CONCLUSIONSmad7 gene transfer inhibits fibrogenic responses of cornea in rats after PRK.

Actins ; genetics ; Animals ; Collagen Type III ; genetics ; Cornea ; pathology ; Fibrosis ; Genetic Therapy ; Ki-67 Antigen ; genetics ; Lentivirus ; genetics ; Photorefractive Keratectomy ; adverse effects ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Smad7 Protein ; genetics ; physiology ; Transforming Growth Factor beta ; physiology

Patients with severe trauma require an extremely timely treatment and transfusion plays an irreplaceable role in the emergency treatment of such patients. An increasing number of evidence-based medicinal evidences and clinical practices suggest that patients with severe traumatic bleeding benefit from early transfusion of low-titer group O whole blood or hemostatic resuscitation with red blood cells, plasma and platelet of a balanced ratio. However, the current domestic mode of blood supply cannot fully meet the requirements of timely and effective blood transfusion for emergency treatment of patients with severe trauma in clinical practice. In order to solve the key problems in blood supply and blood transfusion strategies for emergency treatment of severe trauma, Branch of Clinical Transfusion Medicine of Chinese Medical Association, Group for Trauma Emergency Care and Multiple Injuries of Trauma Branch of Chinese Medical Association, Young Scholar Group of Disaster Medicine Branch of Chinese Medical Association organized domestic experts of blood transfusion medicine and trauma treatment to jointly formulate Chinese expert consensus on blood support mode and blood transfusion strategies for emergency treatment of severe trauma patients ( version 2024). Based on the evidence-based medical evidence and Delphi method of expert consultation and voting, 10 recommendations were put forward from two aspects of blood support mode and transfusion strategies, aiming to provide a reference for transfusion resuscitation in the emergency treatment of severe trauma and further improve the success rate of treatment of patients with severe trauma.