[Cyclin A1 affects the invasion, metastasis, and prognosis of hepatocellular carcinoma].

Objective: To investigate the effect of cyclin A1 on the invasion, metastasis, and prognosis of hepatocellular carcinoma (HCC). Methods: Immunohistochemistry (IHC) was used to detect the expressional condition of cyclin A1 in HCC and paraffin-embedded non-tumor adjacent tissues. Kaplan-Meier method was used for the survival analysis of patients with HCC. Western blot (WB) was used to detect the expression of cyclin A1 in HCCLM3 and QGY-7703 cells. Scratch wound healing assay, transwell migration, and invasion assay were used to detect the effect of cyclin A1 overexpression on cell migration and invasion ability. WB was used to detect changes in the expression of matrix metalloproteinase (MMP) 2, MMP9, and vascular endothelial growth factor (VEGF) after overexpression of cyclin A1. Measurement data were compared using a t-test and analysis of variance. Count data was measured using χ (2) test and the Log-rank method was performed for survival analysis. Results: Cyclin A1 expression rates were higher in the tissues of HCC patients with recurrent metastasis than in the tissues of patients without recurrent metastasis (60.42% vs. 46.81%, χ (2) = 4.711, P < 0.05). The overall postoperative survival time (OS) and disease-free survival (DFS) were shorter in patients with high cyclin A1 expression than those with low cyclin A1 expression (45.9 months vs. 53.1 months; 42.9 months vs. 51.3 months, and P < 0.01). The postoperative OS and DFS were shorter in patients with high cyclin A1 expression and recurrent metastasis than those with low cyclin A1 expression without recurrent metastasis (31.7 months vs. 43.9 months; 18.0 months vs. 31.5 months, and P < 0.05). HCCLM3 and QGY-7703 cells were higher in the cyclin A1-pEX group than in the empty vector (vector) group (1.56 ± 0.06 vs. 0.18 ± 0.01, t = 18.75, P < 0.001; 1.31 ± 0.05 vs.0.37 ± 0.02, t = 15.17, P < 0.001). The migrated distances of HCCLM3 cells in the cyclin A1-pEX group and the vector group were (536.7 ± 14.5) µm and (327.3 ± 9.3) µm, t = 11.84, P < 0.05, respectively, while the migrated distances of QGY-7703 cells in the two groups were (916.7 ± 35.3) µm and (320.0 ± 20.8) µm, t = 13.54, P < 0.01. The migrated numbers of HCCLM3 cells in the cyclin A1-pEX group and vector group were (37.3 ± 2.4) and (7.0 ± 1.2), t = 12.67, P < 0.001, and the number of invasive cells was (73.7 ± 4.1) and (12.6 ± 1.5), t = 12.36, P < 0.001, respectively. The migrated numbers of QGY-7703 cells in the two groups were (153.3 ± 6.0) and (17.7 ± 3.7), t = 17.59, P < 0.001, and the number of invasive cells was (45.0 ± 2.9) and (9.3 ± 1.5), t = 10.66, P < 0.001, respectively. The expression levels of MMP2, MMP9, and VEGF in HCCLM3 and QGY-7703 cells were significantly higher in the cyclin A1-pEX group than those in the vector group (P < 0.05). Conclusion: Cyclin A1 plays an important role in HCC invasion and metastasis, but HCC patients with high cyclin A1 expression have a poor prognosis. Hence, cyclin A1 has high guiding significance for evaluating patient prognosis.

[Research progress in the application of non-thermal atmospheric pressure plasma in dentin bonding].

As a convenient and effective surface modification approach, non-thermal atmospheric pressure plasma (NTAPP)can be used to improve dentin bonding, and has recently become a research focus. Studies have shown that NTAPP can alter dentin surface properties, improve the penetration and polymerization of adhesives, stimulate the cross-linking of collagen, and change the micro-morphology and element content of dentin surface, thus improve the dentin bonding quality. This article introduces the current research progress in the application of NTAPP in the field of dentin bonding, in order to provide innovative information for future research in optimization of the quality of dentin bonding.

[Research progress in the application of dopa-inspired compounds to improve the dentin-resin bonding].

Mussle foot protein has a main component which is named dopa. Dopa can be used to promote a relatively firm adhesion of mussels to the surface of solid materials through forming dihydrogen bonds, π-π/π-cation bonds and chelating metals,etc. To exploit these interactions, there is the opportunity to apply dopa-inspired compounds to improve the dentin-resin bonding. The current review provides valuable information concerning the mechanism of adhesion mediated by mussel foot protein and describes the application of dopa-inspired compounds in the dentin-resin bonding. The article provides novel information for future research in optimization of the properties of dentin-resin bonding.

Comparison of endoscope-assisted versus conventional resection of parotid tumors.

Endoscopically-assisted partial parotidectomy for benign tumours has been reported, but we have evaluated its feasibility through different concealed incisions compared with conventional parotidectomy. A total of 124 patients with parotid tumours were enrolled in this retrospective study: an endoscopically-assisted group (n=37) compared with a group operated on conventionally (n=87). The incision for endoscopically-assisted partial, total parotidectomy and selective neck dissection was based on location and pathological characters of the parotid tumour. The sex and age of the patients, diameter of the tumour, and histopathological features were comparable between the two groups. The mean length of the incision in the endoscopic group was significantly shorter than that in the conventional group. However, intraoperative blood loss, operating time, and duration of hospital stay were significantly reduced, and postoperative secretion of saliva was significantly improved in the endoscopic group, among whom there were no recurrences of tumour. More importantly, all patients who had endoscopically-assisted operations were satisfied with the cosmetic result. Endoscopically-assisted parotidectomy is superior to conventional resection as judged by postoperative cosmetic and functional outcomes. It is noteworthy that the site of incision depends mainly on location, and on the suspected low grade of malignancy of the parotid tumour seen on preoperative computed tomography and magnetic resonance images.

[Virtual planning and 3D printing modeling for mandibular reconstruction with fibula free flap].

Objective: To evaluate the use of virtual planning and 3D printing modeling in mandibular reconstruction and compare the operation time and surgical outcome of this technique with conventional method. Methods: Between June 2013 and June 2017, A total of 18 patients underwent the mandibular reconstruction with fibula free flap in the Affiliated Hospital of Qingdao University.Among 18 patients, there were 11 males and 7 females with an average age of 36.5 years (21-73 years). Nine patients underwent vascularized fibula flap mandibular reconstruction using virtual planning and 3D printing modeling.Titanium plates were pre-bent using the models and cutting guides which were used for osteotomies.Another 9 patients who underwent mandibular reconstruction using fibula flap without aid of virtual planning and 3D printing models were selected as control group. The operation time was recorded and compared in two groups. Accuracy of reconstruction was measured by superimposing the preoperative image onto the postoperative image of mandible. The selected bony landmark, distance and angle were measured. Results: The mean total operation time were 4.7-6.2(5.5±0.5) h in computer-assisted group and 5.6-7.5(6.6±0.7) h in conventional group, respectively. The operation time was shorter in computer-assisted group. The difference between the preoperative and postoperative intercondylar distances, intergonial angle distances, anteroposterior distances were(2.6±1.4)vs(4.4±1.6)mm, (2.9±1.2)vs(4.7±1.7)mm, (4.2±1.4) vs(5.9±1.8)mm in the computer-assisted and conventional group, respectively. The differences between the preoperative and postoperative mandible were smaller in the computer-assisted group. Conclusions: Virtual planning and 3D printing modeling have the potential to increase mandibular reconstruction accuracy and reduce operation time. We believe that this technology for mandibular reconstruction in selected patients can significantly improve the quality of reconstruction.

Methyl-CpG-binding protein MBD2 plays a key role in maintenance and spread of DNA methylation at CpG islands and shores in cancer.

Cancer is characterised by DNA hypermethylation and gene silencing of CpG island-associated promoters, including tumour-suppressor genes. The methyl-CpG-binding domain (MBD) family of proteins bind to methylated DNA and can aid in the mediation of gene silencing through interaction with histone deacetylases and histone methyltransferases. However, the mechanisms responsible for eliciting CpG island hypermethylation in cancer, and the potential role that MBD proteins play in modulation of the methylome remain unclear. Our previous work demonstrated that MBD2 preferentially binds to the hypermethylated GSTP1 promoter CpG island in prostate cancer cells. Here, we use functional genetic approaches to investigate if MBD2 plays an active role in reshaping the DNA methylation landscape at this locus and genome-wide. First, we show that loss of MBD2 results in inhibition of both maintenance and spread of de novo methylation of a transfected construct containing the GSTP1 promoter CpG island in prostate cancer cells and Mbd2-/- mouse fibroblasts. De novo methylation was rescued by transient expression of Mbd2 in Mbd2-/- cells. Second, we show that MBD2 depletion triggers significant hypomethylation genome-wide in prostate cancer cells with concomitant loss of MBD2 binding at promoter and enhancer regulatory regions. Finally, CpG islands and shores that become hypomethylated after MBD2 depletion in LNCaP cancer cells show significant hypermethylation in clinical prostate cancer samples, highlighting a potential active role of MBD2 in promoting cancer-specific hypermethylation. Importantly, co-immunoprecipiation of MBD2 shows that MBD2 associates with DNA methyltransferase enzymes 1 and 3A. Together our results demonstrate that MBD2 has a critical role in 'rewriting' the cancer methylome at specific regulatory regions.

Seawater Incursion Events in a Cretaceous Paleo-lake Revealed by Specific Marine Biological Markers.

Many large paleo-lakes in North China were formed after the Triassic Era. Seawater incursion events (SWIEs) in these lakes have been extensively discussed in the literature, yet lack reliable methodology and solid evidence, which are essential for reconstructing and confirming SWIEs. The present study employs specific marine biological markers (24-n-propyl and 24-isopropyl cholestanes) to trace SWIEs in a dated core taken from the Songliao Basin (SLB). Two SWIEs were identified. The first SWIE from 91.37 to 89.00 Ma, was continuous and variable but not strong, while the second SWIE from 84.72 to 83.72 Ma was episodic and strong. SWIEs caused high total organic carbon (TOC) and negative δ(13)Corg values in the sediments, which were interpreted as an indication of high productivity in the lake, due to the enhancement of nutrient supplies as well as high levels of aqueous CO2, due to the mixing of alkaline seawater and acidic lake water. The SWIEs in SLB were controlled by regional tectonic activity and eustatic variation. Movement direction changes of the Izanagi/Kula Plate in 90 Ma and 84 Ma created faults and triggered SWIEs. A high sea level, from 90 to 84 Ma, also facilitated the occurrence of SWIEs in SLB.

Aberrant promoter methylation of the CD4 gene in peripheral blood cells of mastitic dairy cows.

Bovine mastitis is the most common and costly disease of dairy cattle. Cluster of differentiation 4 (CD4) is closely related to the immune response in mastitis. We quantified promoter CpG methylation levels of the CD4 gene in Chinese Holsteins with clinical mastitis (CM) and in healthy controls; these levels were quantitatively detected with bisulfite pyrosequencing assays and confirmed by cloning sequencing. We found that the bovine CD4 promoter had 16% more methyl groups in the cows with CM (75.0 ± 5.8%) compared to the controls (59.0 ± 8.5%). The decreased expression level of CD4 in CM cows may be downregulated by the increased DNA methylation levels in the CD4 promoter. Two-dimensional hierarchical clustering analyses showed large differences in promoter CD4 methylation between mastitic and healthy cows; the dendrogram clearly distinguished the cows with clinical mastitis from healthy controls based on methylation levels. The DNA methylation level of the CD4 gene was strongly influenced by mastitis status in all comparisons. We suggest that the DNA methylation level of the CD4 promoter can be used as a molecular marker for clinical mastitis in dairy cows.

Differential expression of Toll-like receptor genes in lymphoid tissues between Marek's disease virus-infected and noninfected chickens.

Toll-like receptors (TLR) are trans-membrane sensors recognizing invading microbes. Toll-like receptors play a central role in initiating immune responses against several pathogens. In this study, we investigated the response of TLR and downstream genes to Marek's disease virus (MDV) infection. Forty 1-d-old chicks were randomly divided into 2 groups, with 20 chicks infected with MDV and 20 chicks mock-infected. Four chickens were euthanized respectively from infected and age-matched noninfected groups at 4, 7, 14, 21, and 28 d postinfection (dpi). Bursas, spleens, and thymuses were removed. The differential expression of TLR genes, including TLR3, TLR5, TLR7, TLR15, and TLR21, and downstream genes of TLR7, including MyD88, TRAF3, TRAF6, IFNA, IFNB, and IL6, in lymphoid tissues of MDV-infected and noninfected chickens was determined by real-time PCR. The results showed that the change of TLR genes was different in 3 lymphoid tissues. Expression of TLR7 and MyD88 was upregulated at 14 dpi and downregulated at 28 dpi in MDV-infected compared with noninfected spleens. The TRAF6 and IFNB were upregulated, and TRAF3, IFNA, and IL6 genes showed increasing trends in MDV-infected compared with noninfected spleens at 14 dpi. The expression of TLR3 and TLR15 genes was downregulated in MDV-infected compared with noninfected spleens at 28 dpi. The results indicated that TLR7 and its downstream genes were a response to MDV infection at 14 dpi. However, the function of TLR was impaired when the infection entered the tumor transformation phase. In bursas, TLR3 and TLR15 genes were upregulated at 7 and 4 dpi, respectively. It indicated that TLR3 and TLR15 might be involved in response to MDV infection in bursa at early phases. However, no differential expression of TLR genes was observed between MDV-infected and noninfected thymuses, which indicated that the thymus had little response to MDV infection mediated by TLR.

Epigenetic-induced repression of microRNA-205 is associated with MED1 activation and a poorer prognosis in localized prostate cancer.

Deregulation of microRNA (miRNA) expression can have a critical role in carcinogenesis. Here we show in prostate cancer that miRNA-205 (miR-205) transcription is commonly repressed and the MIR-205 locus is hypermethylated. LOC642587, the MIR-205 host gene of unknown function, is also concordantly inactivated. We show that miR-205 targets mediator 1 (MED1, also called TRAP220 and PPARBP) for transcriptional silencing in normal prostate cells, leading to reduction in MED1 mRNA levels, and in total and active phospho-MED1 protein. Overexpression of miR-205 in prostate cancer cells negatively affects cell viability, consistent with a tumor suppressor function. We found that hypermethylation of the MIR-205 locus was strongly related with a decrease in miR-205 expression and an increase in MED1 expression in primary tumor samples (n=14), when compared with matched normal prostate (n=7). An expanded patient cohort (tumor n=149, matched normal n=30) also showed significant MIR-205 DNA methylation in tumors compared with normal, and MIR-205 hypermethylation is significantly associated with biochemical recurrence (hazard ratio=2.005, 95% confidence interval (1.109, 3.625), P=0.02), in patients with low preoperative prostate specific antigen. In summary, these results suggest that miR-205 is an epigenetically regulated tumor suppressor that targets MED1 and may provide a potential biomarker in prostate cancer management.

The wavelet-based cluster analysis for temporal gene expression data.

A variety of high-throughput methods have made it possible to generate detailed temporal expression data for a single gene or large numbers of genes. Common methods for analysis of these large data sets can be problematic. One challenge is the comparison of temporal expression data obtained from different growth conditions where the patterns of expression may be shifted in time. We propose the use of wavelet analysis to transform the data obtained under different growth conditions to permit comparison of expression patterns from experiments that have time shifts or delays. We demonstrate this approach using detailed temporal data for a single bacterial gene obtained under 72 different growth conditions. This general strategy can be applied in the analysis of data sets of thousands of genes under different conditions.

Synthesis of a muscarinic receptor antagonist via a diastereoselective Michael reaction, selective deoxyfluorination and aromatic metal-halogen exchange reaction.

An efficient synthesis of a structurally unique, novel M(3) antagonist 1 is described. Compound 1 is conveniently disconnected retrosynthetically at the amide bond to reveal the acid portion 2 and the amine fragment 3. The synthesis of key intermediate 2 is highlighted by a ZnCl(2)-MAEP complex 19 catalyzed diastereoselective Michael reaction of dioxolane 7 with 2-cyclopenten-1-one (5) to establish the contiguous quaternary-tertiary chiral centers and a subsequent geminal difluorination of ketone 17 using Deoxofluor in the presence of catalytic BF(3).OEt(2). The synthesis of the amine moiety 3 is highlighted by the discovery of a novel n-Bu(3)MgLi magnesium-halogen exchange reaction for selective functionalization of 2,6-dibromopyridine. This new and practical metalation protocol obviated cryogenic conditions and upon quenching with DMF gave 6-bromo-2-formylpyridine (26) in excellent yield. Further transformations afforded the amine fragment 3 via reductive amination with 35, Pd-catalyzed aromatic amination, and deprotection. Finally, the highly convergent synthesis of 1 was accomplished by coupling of the two fragments. This synthesis has been used to prepare multi-kilogram quantities of the bulk drug.

Determination of quinolizidine alkaloids in traditional Chinese herbal drugs by nonaqueous capillary electrophoresis.

A rapid method for the determination of quinolizidine alkaloids by nonaqueous capillary electrophoresis was developed. A total of 10 alkaloids (matrine, sophocarpine, oxymatrine, oxysophocarpine, sophoridine, cytisine, sophoramine, aloperine, lehmannine and dauricine) could be easily separated within 18 min. A running buffer composed of 50 mM ammonium acetate, 10% tetrahydrofuran and 0.5% acetic acid in methanol was found to be the most suitable for this separation. Five of these alkaloids were selected for further studies. The linear calibration ranges were 2.51-50.1 microg/ml for sophoridine and sophocarpine, 2.71-54.2 microg/ml for matrine, 3.30-65.9 microg/ml for oxymatrine, and 3.10-62.0 microg/ml for oxysophocarpine. The recovery of the five alkaloids was 98.0-101.3% with relative standard deviations from 1.03 to 2.68% (n=5). The limits of detection for all 10 alkaloids were over the range 0.93-2.31 microg/ml. The method was successfully applied to the phytochemical analysis of alkaloid extracts from three commonly used traditional Chinese herbal drugs: Sophora flavescens Ait. (Kushen), S. alopecuroides L. (Kudouzi or Kugancao) and S. tonkinensis Gapnep (Shandougen).

Determination of L-threonate in calcium L-threonate preparations by capillary electrophoresis with indirect UV detection.

A validated capillary electrophoresis method with indirect UV detection for the determination of L-threonate in a calcium L-threonate (Ca-Th) chewable tablet and dry syrup was described. The 2,6-naphthalenedicarboxylic acid (NDC) was used as the background carrier ion and the tetradecyltrimethylammonium bromide (TTAB) was used as electroosmotic flow modifier. The running buffer contained 2 mM NDC, 6 mM disodium carbonate and 0.2 mM TTAB. The detection wavelength was set at 240 nm. A linear calibration range of 50-500 microg/mL was obtained (r = 0.9996). The limit of detection and limit of quantitation were found to be 6 microg/mL and 20 microg/mL, respectively. The recovery was 99.45% (RSD = 0.57%, n = 5) and 99.12% (RSD = 0.48%, n = 5) for the tablet and dry syrup preparation, respectively. Repeatability tests on the migration times or peak areas proved that the results were of high precision. The RSD of peak area ratio was lower than 1% (0.74%, n = 5). The factors influencing quantitation were discussed and three batches of chewable tablet and also of dry syrup were assayed by the proposed method.

Significance of plasma and peripheral blood mononuclear cell derived HIV-1 sequences in establishing epidemiologic linkage between two individuals multiply exposed to HIV-1.

Establishing epidemiologic linkage in individuals multiply exposed to HIV can be a difficult task. To date, only peripheral blood mononuclear cell (PBMC)-derived sequences have been used in studying HIV-1 transmission between individuals. So far, the combined utility of plasma and PBMC-derived HIV-1 sequences has not been assessed in establishing epidemiologic linkage in people involved in transmission of HIV. In this study, both PBMC (DNA) and plasma (RNA) derived viral quasispecies was used in establishing epidemiologic linkage between two infected individuals (B-90 and B-69) multiply exposed to HIV-1 via injecting drug use. A detailed sequence, and phylogenetic analyses of HIV-1V3 region quasispecies derived from these two compartments clearly demonstrated compartmentalization of viral quasispecies between PBMC and plasma. More importantly, these data also demonstrate that in order to establish epidemiologic linkage between individuals multiply exposed to HIV-1, analyses of viral strains from both plasma and PBMC compartments may be necessary. The PBMC compartment alone may not provide sufficient information on epidemiologic linkage, overall diversification of viral quasispecies, replacement of older strains and the emergence of new viral recombinant strains in vivo. These are the first analyses that demonstrate the incremental value of plasma derived sequences, when used in conjunction with PBMC-derived sequences, in establishing the epidemiologic linkage between individuals multiply exposed to HIV parenterally. Further, the plasma derived HIV-1 sequences may prove to be invaluable in predicting a recent transmission between two epidemiologically-linked individuals.

Assay for the determination of low dosage form of formoterol dry syrup by capillary electrophoresis with head-column field-amplified sample stacking.

The development of a capillary zone electrophoresis method with head-column field-amplified sample stacking injection for the determination of formoterol (FMTR) in a low dosage dry syrup form was described. To obtain the highest sensitivity, the sample solution was prepared by high content of organic solvent with the presence of a small amount of H+ (60-100 microM) and the capillary inlet end was dipped in water before electroinjection. This method was fully validated in terms of repeatability (RSDs for migration time, peak area of FMTR and peak area ratio between FMTR and I.S. at 1 microg/ml of FMTR was 0.76, 1.10 and 0.55% respectively), reproducibility (RSDs from different capillaries, analytes, days and instruments were 1.52%, 1.04%, 1.16% and 1.93% respectively), linearity (y = 0.827x - 0.085, r = 0.9993 (n = 6) over the range of 0.25-2.0 microg/ml), limits of quantitation, ruggedness and robustness. The method was applied to the determination of the drug in commercial dry syrup preparation (recovery was 100.9%, RSD = 1.5%, n = 5) and proved to be fast and reliable for the quantitation analysis of FMTR in the pharmaceutical form.

A new approach to the problem of multiple comparisons in the genetic dissection of complex traits.

Saturated genetic marker maps are being used to map individual genes affecting quantitative traits. Controlling the "experimentwise" type-I error severely lowers power to detect segregating loci. For preliminary genome scans, we propose controlling the "false discovery rate," that is, the expected proportion of true null hypotheses within the class of rejected null hypotheses. Examples are given based on a granddaughter design analysis of dairy cattle and simulated backcross populations. By controlling the false discovery rate, power to detect true effects is not dependent on the number of tests performed. If no detectable genes are segregating, controlling the false discovery rate is equivalent to controlling the experimentwise error rate. If quantitative loci are segregating in the population, statistical power is increased as compared to control of the experimentwise type-I error. The difference between the two criteria increases with the increase in the number of false null hypotheses. The false discovery rate can be controlled at the same level whether the complete genome or only part of it has been analyzed. Additional levels of contrasts, such as multiple traits or pedigrees, can be handled without the necessity of a proportional decrease in the critical test probability.

Determination of metformin in plasma by capillary electrophoresis using field-amplified sample stacking technique.

A capillary electrophoresis method was described for the determination of metformin in human plasma based on the extraction of the ion-pair with bromothymol blue into chloroform. Phenformin was used as internal standard. Field-amplified sample stacking injection was employed with an electrokinetic injection voltage of 10 kV for 10 s. The running buffer was 0.1 M phosphate buffer (pH 2.5), running voltage was 20 kV and the UV absorbance detection was set at 195 nm. The limit of quantitation was 0.25 microg/ml. Linearity range of calibration curve was 0.25 to 3.5 microg/ml. Recoveries for three levels (0.25, 1 and 2 microg/ml) were 80.24%, 67.44% and 58.97% (n = 5 for each level), respectively. The intra-day precisions for the three levels were 11.9%, 3.09% and 4.33% and the inter-day precisions were 12.4%, 4.57% and 4.94%, respectively. The concentrations of metformin hydrochloride in human plasma of eight volunteers were measured after orally administrating metformin enteric-capsule and tablet.

Determination of thiamphenicol in human plasma by micellar electrokinetic capillary chromatography.

A micellar electrokinetic chromatographic method is described for the determination of thiamphenicol in human plasma. The plasma sample was basified by adding K2HPO4 and was then extracted with ethyl acetate. After the solvent was evaporated, the residue was reconstituted in water. Approximately 40 nl of the solution were injected hydrodynamically. The running buffer was 20 mM borate (pH 9.2) containing 40 mM sodium dodecyl sulfate and 10% acetonitrile. The applied voltage was 18 kV and the detector wavelength was set at 195 nm. On-column sample stacking was achieved during the analysis to enhance the sensitivity; the limit of quantitation was 0.1 microg/ml. Linearity was over the range of 0.2 to 10 microg/ml. Recovery was 93.7+/-3.3%, the intra-day precision and accuracy was 99.6+/-2.8%; the inter-day precision and accuracy was 98.4+/-3.4%. The concentration of thiamphenicol in human plasma from eight volunteers was measured after administering thiamphenicol capsules orally.

[Development of resistance of herpes simplex virus to antivirus drugs in vitro].

Resistant variants of HSV-1 wt strain to ACV, CC, DHPG and PFA can be selected after several passages in drug-containing cultures. The degree of resistance of different variants varied and emerged at different times. The combination of antiviral agents can delay and even prevent the emergence of drug-resistant variants. At the same time, the concentration, dose and, therefore, toxicity of the antiviral agents can also be reduced. So, it is a feasible method for treating resistant HSV infections. Cross-sensitivity tests showed that ACVr variants are resistant to ACV, DHPG and PFA, but sensitive to CC; PFAr variants are sensitive to ACV, CC and DHPG; CCr variants are sensitive to ACV and DHPG, but resistant to PFA; DHPGr variants are sensitive to ACV, CC and PFA. These results suggest that the study of cross-sensitivity of HSV strains in vitro provide information which will aid the design of suitable therapy for drug-resistant HSV infections.