Circulating tumor DNA (ctDNA) comes from tumor, reflecting the genetic information of the tumor well, and will change with the progress of tumor. In recent years, the unique capabilities of ctDNA have attracted much attention and been widely studied. In this paper, based on the summary of the source, properties and sample processing of ctDNA, its detection technology and application in cancer diagnosis and treatment are reviewed. The roles and importance of ctDNA reference material in second-generation sequencing are described. The urgency of establishing uniform standards and specifications of ctDNA in various processes, such as samples collection, storage, quantitative testing and data analysis, has been pointed out.

The ICR(Institute of Cancer Research)mouse infection model was constructed to study the pathogenicity of Sal-monella Telelkebir serotype,and the pathogenic identification of mouse isolates was carried out.Observe the bacterial excretion cycle,evaluate the pathogenicity of Salmonella serotype to mice,and calculate the LD50 by the changes in clinical characteris-tics,histopathology and tissue bacterial load of infected mice;by flight mass spectrometry,biochemical identification,serotype identification,molecular typing and other experiments,compared with human isolates;virulence gene analysis was carried out by PCR experiment and whole genome sequencing.The LD50 of Salmonella Telelkebir is 2.67 × 108 CFU/mL;curling and fluffing may occur 0.5 h after infection;autopsy of dead mice showed that the small intestine was severely congested,with more bubbles and fluid accumulation,cecal necrosis,liver apical degeneration and necrosis,necrotic foci on the surface of the kidney and spleen atrophy;the bacterial load of spleen,kidney,lung,liver and jejunum in mice reached its peak at 3 days after infection,while that of heart at 6 days;the bacterial excretion time of the high-dose group exceeded 100 days;The level of CD3 in tissues increased with increasing dose,with inflammatory cell infiltration,myocardial capillary dilation and hyperemia,large area of vacuoles,degeneration and necrosis of hepatocytes,obvious enlargement of splenic sinus,blurred zoning,thickening of glomerular basement membrane,partial exfoliation of ciliated epithelium,atrophy and exfoliation of jejunal villi;PCR and whole genome sequencing revealed Salmonella-related virulence genes such as cdtB,plt A and pltB.This study was the first to successfully establish the ICR mouse model of Salmonella Telelkebir,demonstrating that this serotype of Salmonella has some pathogenicity.

Background: Genetic defects in the human thyroid-stimulating hormone (TSH) receptor (TSHR) gene can cause congenital hypothyroidism (CH). However, the biological functions and comprehensive genotype–phenotype relationships for most TSHR variants associated with CH remain unexplored. We aimed to identify TSHR variants in Chinese patients with CH, analyze the functions of the variants, and explore the relationships between TSHR genotypes and clinical phenotypes. Methods: In total, 367 patients with CH were recruited for TSHR variant screening using whole-exome sequencing. The effects of the variants were evaluated by in-silico programs such as SIFT and polyphen2. Furthermore, these variants were transfected into 293T cells to detect their Gs/cyclic AMP and Gq/11 signaling activity. Results: Among the 367 patients with CH, 17 TSHR variants, including three novel variants, were identified in 45 patients, and 18 patients carried biallelic TSHR variants. In vitro experiments showed that 10 variants were associated with Gs/cyclic AMP and Gq/11 signaling pathway impairment to varying degrees. Patients with TSHR biallelic variants had lower serum TSH levels and higher free triiodothyronine and thyroxine levels at diagnosis than those with DUOX2 biallelic variants. Conclusions We found a high frequency of TSHR variants in Chinese patients with CH (12.3%), and 4.9% of cases were caused by TSHR biallelic variants. Ten variants were identified as loss-of-function variants. The data suggest that the clinical phenotype of CH patients caused by TSHR biallelic variants is relatively mild. Our study expands the TSHR variant spectrum and provides further evidence for the elucidation of the genetic etiology of CH.

Objective To evaluate the effects of high-fat diet on the pharmacokinetics of metronidazole in Chinese healthy adult subjects.Methods This program is designed according to a single-center,randomized,open,single-dose trial.Forty-seven healthy subjects were assigned to receive single dose of metronidazole tablets 200 mg in either fasting and high-fat diet state,and blood samples were taken at different time points,respectively.The concentrations of metronidazole in plasma were determined by high performance liquid chromatography-mass spectromentry.Results The main pharmacokinetic parameters of metronidazole in fasting state and high-fat diet state were as follows:Cmax were(4 799.13±1 195.32)and(4 044.17±773.98)ng·mL-1;tmax were 1.00 and 2.25 h;t1/2 were(9.11±1.73)and(9.37±1.79)h;AUC0_t were(5.59±1.19)x 104 and(5.51±1.18)x 104 ng·mL-1·h;AUC0_∞ were(5.79±1.33)x 104 and(5.74±1.32)× 104 ng·mL-1·h.Compared to the fasting state,the tmaxof the drug taken after a high fat diet was delayed by 1.25 h(P＜0.01),Cmax,AUC0_t,AUC0-∞ were less or decreased in different degrees,but the effects were small(all P＞0.05).Conclusion High-fat diet has little effects on the pharmacokinetic parameters of metronidazole,which does not significantly change the degree of drug absorption,but can significantly delay the time to peak.

Objective To evaluate the bioequivalence of metronidazole tablet and reference formulation in Chinese healthy subjects.Methods A single-dose,two-cycle,randomized,open,self-crossover trial was designed with 48 healthy subjects randomly assigned to fasting or postprandial group.For each group,a single oral dose of metronidazole tablet(200 mg)or a reference preparation(200 mg)per cycle were enrolled.The concentration of metronidazole in plasma was measured by high performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS).The non-compartmental model was applied to calculate the pharmacokinetic parameters for bioequivalence analysis via SAS 9.3 software.Results The main pharmacokinetic parameters of test and reference metronidazole tablets in the fasting group were as follows,the Cmax were(4 855.00±1 383.97)and(4 799.13±1 195.32)ng·h·mL-1;the AUC0-t were(54 834.68±12 697.88)and(55 931.35±11 935.28)ng·h·mL-1;the AUC0-∞ were(56 778.09±13 937.76)and(57 922.83±13 260.54)ng·h·mL-1;the Tmax were respectively 1.17 and 1.00 h;t1/2 were(8.99±1.76)and(9.11±1.73)h,respectively.The ratio of the geometric mean and its 90％confidence intervals(CI)of Cmax,AUC0-t and AUC0-∞ were all within the equivalent interval of 80.00％-125.00％.As for postprandial conditions,the main pharmacokinetic parameters of test and reference metronidazole tablets were as follows,the Cmax were(4 057.08±655.08)and(4 044.17±773.98)ng·h·mL-1;the AUC0-t were(55 956.42±12 228.12)and(55 121.04±11 784.55)ng·h·mL-1;the AUC0-∞ were(58 212.83±13 820.00)and(57 350.38±13 229.46)ng·h·mL-1;the Tmax were 2.50 and 2.25 h;the t1/2 were(9.37±1.68)and(9.37±1.79)h,respectively.The ratio of the geometric mean and 90％CI of Cmax,AUC0-t and AUC0-∞ were all within the equivalent interval of 80.00％-125.00％.Conclusion The two preparations were bioequivalent to Chinese healthy adult volunteers under both fasting and fed conditions.

Objective To observe the effects of dexmedetomidine combined with esketamine on early postoperative pain and cognitive function in elderly patients undergoing spinal surgery.Methods The aged spinal surgery patients were divided into control group and treatment group by random number table method.Both groups were anesthetically induced by intramuscular injection of esketamine 3 mg·kg-1,while the control group was anesthetically induced by intravenous injection of propofol 4 mg·kg-1 with constant velocity pump.The treatment group was given 1 μg·kg-1 dexmedetomidine by intravenous pump for 10 min,and then continued pumping at 0.5 μg·kg-1 rate.The changes of vital signs 5 min before surgery(T1),5 min after surgery(T2),at the end of surgery(T3),at the time of recovery(T4),early postoperative pain,cognitive function,the time of the first patient control analgesia(PC A),the cumulative dosage of sufentanil in different time periods within 48 h and the occurrence of adverse drug reactions were observed in the 2 groups.Results 44 patients were included in the control group and 45 patients in the treatment group,respectively.At T2,T3 and T4,the heart rate of treatment group were(82.51±3.05),(80.15±3.21)and(81.51±3.04)beat·min-1,and that of control group were(92.54±3.10),(93.52±3.05)and(88.45±3.51)beat·min-1,respectively.The mean arterial pressure(MAP)of the treatment group were(54.51±3.58),(55.25±3.21)and(60.25±3.24)mmHg;and that of the control group were(73.25±3.54),(70.52±3.20)and(68.51±3.05)mmHg,respectively.The blood oxygen saturation(SPO2)of treatment groups were(98.56±0.38)％,(98.25±0.35)％and(99.02±0.14)％;and the SPO2 of control group were(94.52±0.35)％,(95.25±0.25)％and(96.25±0.32)％,respectively.Visual analogue pain(VAS)scores were(5.69±1.12),(5.02±0.89),(4.52±0.65)and(4.01±0.45)scores at 2,4,6 and 8 h after operation,respectively;the control group were(6.25±1.35),(5.46±1.12),(4.98±0.84)and(4.25±0.52)scores,respectively.24,36 and 72 h after operation,the scores of MMSE in treatment group were 24.25±1.15,26.25±1.14,27.25±0.89 and 28.86±0.62,respectively;the control group were 22.52±1.02,24.25±1.12,26.58±0.87 and 28.78±0.52,respectively.Compared with the control group,there were statistically significant differences in the above indexes of treatment groups(all P＜0.05).The adverse drug reactions in the control group were mainly lethargy,respiratory depression,nausea and vomiting,and the adverse drug reactions in the treatment group were mainly lethargy,nausea and vomiting,and the incidence of total adverse drug reactions in the treatment group and the control group was 6.67％and 22.73％,respectively,with statistical significance(P＜0.05).Conclusion Dexmedetomidine combined with esketamine is safe and effective in elderly patients undergoing spinal surgery.It can effectively reduce early postoperative pain and quickly restore cognitive function.

Objective The purpose of this study was to investigate the bacterial communities of biting midges and ticks collected from three sites in the Poyang Lake area,namely,Qunlu Practice Base,Peach Blossom Garden,and Huangtong Animal Husbandry,and whether vectors carry any bacterial pathogens that may cause diseases to humans,to provide scientific basis for prospective pathogen discovery and disease prevention and control. Methods Using a metataxonomics approach in concert with full-length 16S rRNA gene sequencing and operational phylogenetic unit(OPU)analysis,we characterized the species-level microbial community structure of two important vector species,biting midges and ticks,including 33 arthropod samples comprising 3,885 individuals,collected around Poyang Lake. Results A total of 662 OPUs were classified in biting midges,including 195 known species and 373 potentially new species,and 618 OPUs were classified in ticks,including 217 known species and 326 potentially new species.Surprisingly,OPUs with potentially pathogenicity were detected in both arthropod vectors,with 66 known species of biting midges reported to carry potential pathogens,including Asaia lannensis and Rickettsia bellii,compared to 50 in ticks,such as Acinetobacter lwoffii and Staphylococcus sciuri.We found that Proteobacteria was the most dominant group in both midges and ticks.Furthermore,the outcomes demonstrated that the microbiota of midges and ticks tend to be governed by a few highly abundant bacteria.Pantoea sp7 was predominant in biting midges,while Coxiella sp1 was enriched in ticks.Meanwhile,Coxiella spp.,which may be essential for the survival of Haemaphysalis longicornis Neumann,were detected in all tick samples.The identification of dominant species and pathogens of biting midges and ticks in this study serves to broaden our knowledge associated to microbes of arthropod vectors. Conclusion Biting midges and ticks carry large numbers of known and potentially novel bacteria,and carry a wide range of potentially pathogenic bacteria,which may pose a risk of infection to humans and animals.The microbial communities of midges and ticks tend to be dominated by a few highly abundant bacteria.

Objective Viral encephalitis is an infectious disease severely affecting human health.It is caused by a wide variety of viral pathogens,including herpes viruses,flaviviruses,enteroviruses,and other viruses.The laboratory diagnosis of viral encephalitis is a worldwide challenge.Recently,high-throughput sequencing technology has provided new tools for diagnosing central nervous system infections.Thus,In this study,we established a multipathogen detection platform for viral encephalitis based on amplicon sequencing. Methods We designed nine pairs of specific polymerase chain reaction(PCR)primers for the 12 viruses by reviewing the relevant literature.The detection ability of the primers was verified by software simulation and the detection of known positive samples.Amplicon sequencing was used to validate the samples,and consistency was compared with Sanger sequencing. Results The results showed that the target sequences of various pathogens were obtained at a coverage depth level greater than 20×,and the sequence lengths were consistent with the sizes of the predicted amplicons.The sequences were verified using the National Center for Biotechnology Information BLAST,and all results were consistent with the results of Sanger sequencing. Conclusion Amplicon-based high-throughput sequencing technology is feasible as a supplementary method for the pathogenic detection of viral encephalitis.It is also a useful tool for the high-volume screening of clinical samples.

Chronic kidney disease(CKD)commonly used dietary assessments including 24-hour dietary recall(24 h DR)/3-day dietary recall(3DDR),food frequency questionnaire(FFQ),dietary records,and estimation of dietary protein intake based on nitrogen balance.Given the high prevalence of CKD patients in Asian population and the scarcity of research using FFQ method,it is crucial to develop an FFQ suitable for Chinese CKD patients.This review summarizes the advantages and disadvantages of dietary assessment methods for CKD,the current research status,and the content and steps involved in establishing an FFQ,with the aim of providing reference for the modification of FFQ for Chinese CKD patients.

Objective To investigate the performance of brands and types of high-flow nasal cnnula oxygen therapy(HFNC)devices at different altitudes.Methods Four different models of HFNC devices,including R-80S bi-level non-invasive ventilator integrated with HFNC device,HF-60A HFNC device,HFT-300 HFNC device and H-80A HFNC device,were connected with the gas flow meter,simularted head and QuickLung and then put into a low-pressure chamber.The flow rates of the HFNC devices were set to 10,15,20,25,30,35,40,45,50,55 and 60 L/min,and the simulated altitudes of the low-pressure chamber were set to 6 000,5 000,4 000,3 000,2 000,1 000 and 0 m.The actual output airway flow rates,airway pressure changes and trends of the four HFNC devices were recorded at different setting altitudes and flow rates.SPSS 25.0 software was used for statistical analysis.Results The actual output airway flow rates of the four HFNC devices showed an increasing trend as the altitude rose with the simulated altitude of 6 000 m and the setting flow rate kept constant,which increased slowly and even went to decrease when the altitude and flow rate exceeded some limits.The degree of changes in the flow rate with the increasing altitude varied,and there was no uniform pattern.With the rising of altitude,the actual output airway pressure of the four HFNC devices with the flow rate raning from 10 to 35 L/min also increased gradually,which showed a decreasing trend(turning point)after going up to some certain value when the flow rate exceeded 35 L/min,and the altitude where the turning point appeared was lowered as the flow rate increased.Conclusion The actual output airway flow rates and airway pressure during HFNC rise at a high-altitude environment,and generally considerations have to be taken on required airway pressure,patient comfort and the altitude of the patient's usual place of residence when setting the flow rates of the HFNC device.[Chinese Medical Equipment Journal,2024,45(6):49-58]