[Clinical efficacy of single/double 125I-seed strands combined with biliary stents in the treatment of malignant obstructive jaundice].

Objective: To compare the clinical efficacy of single/double 125I-seed strands combined with biliary stents in the treatment of malignant obstructive jaundice. Methods: Totally 67 cases of patients with malignant obstructive jaundice who received single/double125I-seed strands combined with biliary stents implantation from September 2018 to December 2021 were analyzed retrospectively. Among them, 36 patients received single 125I-seed strands combined with biliary stents (single strand group) and 31 patients received double 125I-seed strands combined with biliary stents(double strands group). The technical success rate, clinical success rate, complications, biochemical and tumor indexes at 8 weeks after operation [total bilirubin (TB), direct bilirubin (DB), alanine transaminase (ALT), aspartate transaminase (AST), carbohydrate antigen 19-9 (CA19-9)], stent patency time (SP), median progression-free survival time (mPFS) and median survival time (mOS) were analyzed. Results: There was no significant difference (P>0.05) in technical success rate (100% vs 100%), clinical success rate (97.2% vs 96.8%) and major complications (5.6% vs 6.5%) between single strand group and double strands group. There were significant differences in TB, DB, ALT, AST and CA19-9 indicators between the two groups before and 8 weeks after operation (all P<0.05), but there was no significant difference in the difference value of preoperative and postoperative 8-week indicators between the two groups (all P>0.05).The SP and mPFS of double-stranded stents were longer than those of single-stranded stents.[8.6 months (95%CI:6.9-10.4) vs 6.2 months (95%CI:5.8-6.6), 3.2 months (95%CI:3.0-3.4) vs 3.0 months (95%CI:2.9-3.1), all P<0.05]. The mOS of single and double strands groups was 11.2 months (95%CI:8.3-14.1) and 13.4 months (95%CI:9.9-16.9) respectively, with no statistical difference (P=0.137). Conclusion: Compared with single 125I-seed strands, double 125I-seed strands can prolong biliary SP and mPFS, but the long-term survival index still needs further observation.

[Effects of vibration on the expression of mitochondrial fusion and fission genes and ultrastructure of skeletal muscle in rabbits].

Objective: To study the effects of vibration on the expression of mitochondrial fusion and fission genes and ultrastructure of skeletal muscle in rabbits. Methods: Thirty-two 3.5-month-old New Zealand rabbits were randomly divided into low-intensity group, medium-intensity group, high-intensity group and control group, with 8 rabbits in each group. The rabbits in the experimental group were subjected to hind limb vibration load test for 45 days. The vibration intensity of the high intensity group was 12.26 m/s(2), the medium intensity group was 6.13 m/s(2), and the low intensity group was 3.02 m/s(2) according to the effective value of weighted acceleration[a(hw (4))] for 4 hours of equal energy frequency. The control group was exposed to noise only in the same experimental environment as the medium-intensity group. The noise levels of each group were measured during the vibration load experiment. After the test, the mRNA expression of mitochondrial fusion gene (Mfn1/Mfn2) and fission gene (Fis1, Drp1) by RT-PCR in the skeletal muscles were measured and the ultrastructure of the skeletal muscles were observed in high intensity group. Results: The mRNA expression of mitochondrial in the skeletal muscle tissues of control group, low intensity group, medium intensity group and high intensity group were Mfn1: 3.25±1.36, 3.85±1.90, 4.53±2.31 and 11.63±7.68; Mfn2: 0.68±0.25, 1.02±0.40, 0.94±0.33 and 1.40±0.45; Fis1: 1.05±0.62, 1.15±0.59, 1.53±1.06 and 2.46±1.51 and Drp1: 3.72±1.76, 2.91±1.63, 3.27±2.01 and 4.21±2.46, respectively. Compared with the control group, the expressions of Mfn1 mRNA, Mfn2 mRNA and Fis1 mRNA in the high-intensity group increased significantly (P<0.05) , and the expressions of Mfn2 mRNA in the medium-intensity group and the low-intensity group increased significantly (P<0.05) . Compared with the control group, the ultrastructure of skeletal muscle of high intensity group showed mitochondrial focal accumulation, cristae membrane damage, vacuole-like changes; Z-line irregularity of muscle fibers, and deficiency of sarcomere. Conclusion: Vibration must be lead to the abnormal mitochondrial morphology and structure and the disorder of energy metabolism due to the expression imbalance of mitochondrial fusion and fission genes in skeletal muscles of rabbits, which may be an important target of vibration-induced skeletal muscle injury.

Cell-free DNA from bile outperformed plasma as a potential alternative to tissue biopsy in biliary tract cancer.

BACKGROUND: Biliary tract cancers (BTCs) are rare and highly heterogenous malignant neoplasms. Because obtaining BTC tissues is challenging, the purpose of this study was to explore the potential roles of bile as a liquid biopsy medium in patients with BTC. PATIENTS AND METHODS: Sixty-nine consecutive patients with suspected BTC were prospectively enrolled in this study. Capture-based targeted sequencing was performed on tumor tissues, whole blood cells, plasma, and bile samples using a large panel consisting of 520 cancer-related genes. RESULTS: Of the 28 patients enrolled in this cohort, tumor tissues were available in eight patients, and plasma and bile were available in 28 patients. Somatic mutations were detected in 100% (8/8), 71.4% (20/28), and 53.6% (15/28) of samples comprising tumor tissue DNA, bile cell-free DNA (cfDNA), and plasma cfDNA, respectively. Bile cfDNA showed a significantly higher maximum allele frequency than plasma cfDNA (P = 0.0032). There were 56.2% of somatic single-nucleotide variant (SNVs)/insertions and deletions (indels) shared between bile and plasma cfDNA. When considering the genetic profiles of tumor tissues as the gold standard, the by-variant sensitivity and positive predictive value for SNVs/indels in bile cfDNA positive for somatic mutations were both 95.5%. The overall concordance for SNVs/indels in bile was significantly higher than that in plasma (99.1% versus 78.3%, P < 0.0001). Moreover, the sensitivity of CA 19-9 combined with bile cfDNA achieved 96.4% in BTC diagnosis. CONCLUSION: We demonstrated that bile cfDNA was superior to plasma cfDNA in the detection of tumor-related genomic alterations. Bile cfDNA as a minimally invasive liquid biopsy medium might be a supplemental approach to confirm BTC diagnosis.

[Targeted therapy for malignant peripheral nerve sheath tumor: translational research and clinical application].

Malignant peripheral nerve sheath tumor (MPNST) is a rare invasive soft tissue sarcoma that originates from peripheral nerve branches and peripheral nerve sheaths. Early radical surgery is an effective treatment for MPNST. Since it is insensitive to radiotherapy and chemotherapy, the disease manifests a rapid progression, poor prognosis and high mortality. In recent years, the translational researches on the driving factors and therapeutic targets of MPNST have been rapidly developed, including the pathways of NF1-Ras, Raf-MEK-ERK, PI3K-AKT-mTOR, Wnt signaling, and abnormal expressions of apoptotic proteins, the general loss of polycomb repressive complex 2 (PRC2), upregulation of the HDAC family, abnormal expressions of receptor tyrosine kinases, expressions of programmed cell death ligand (PD-L1), aurora kinase and various microRNAs.This review summarizes the current translational researches on potential therapeutic targets of MPNST, and the clinical trials which provide helpful information for MPNST targeted therapy.

[The effects of silica dust on the expression of MyD88 and TRAF6 mRNA of lung macrophages in rats].

Objective: To investigate the effects of silica dust on the expression of Myeloid differentiation factor 88 (MyD88) mRNA and tumor necrosis factor receptor-associated factor (TRAF6) mRNA of lung macrophages in rats. Methods: Selecting 40 SPF-class Wistar rats with average weight (200±20) g randomly divided into control group and 30 d, 60 d, 120 d experimental groups with 10 rats in each group according to body weight. The experimental groups rats were injected with 1 ml of SiO(2) (100 mg/ml) suspension through the trachea into lung only once, then they were respectively killed after 30, 60, 120 days. The control group rats were injected with 1 ml of saline into lung, and killed after 120 days. The lungs of the rats were taken for pathological observation. Lung macrophages were extracted and counted, and their activity was detected by MTT. RT-qPCR was used to assess the relative contents of MyD88 mRNA and TRAF6 mRNA. Results: Silica dust inhalation led to infiltration of lung tissue cells, thickening the alveolar wall and destruction of alveolar structure. The longer the exposure to dust, the more obvious the results were. The number of macrophages in all experimental groups and activity in the 30 d, 60 d groups were significantly higher than that in the control group (P<0.05) . Among them, 30 d group had the largest number and the highest activity. Compared with the control group, the expression of MyD88 mRNA and TRAF6 mRNA of lung macrophages in rats increased in the experimental groups (P<0.05) , especially in the 60 d group. Conclusion: Silica dust inhalation can increase the expression of MyD88 and TRAF6 in macrophages, suggesting that silica dust can induce silicosis fibrosis by activating TLR/NF-κB signal pathway.

[Study on the Specific Complexation of GMDTC and Metal Ion].

Objective: Study the response of GMDTC to cadmium ions and metal ions in vivo to determine whether GMDTC are specifically complexed with cadmium ions to provide a reference for the safety and dfficacy of GMDTC. Methods: Complexometric titration, HPLC and HPLC-MS were applied to research the complexation reaction of GMDTC and various metal ions. The molecular ion peak of GMDTC, GMDTC-Cd complex and GMDTC-Pb complex also detected by LC-MS. Additionally, the initial structure was determined by DFT simulation method. Results: Results of complexometric titration and HPLC detection showed that GMDTC characteristic absorption peak area was proportional to the concentration of itself and there was no color change and peak time change when the GMDTC mixed with Ca(2+), Fe(2+), Mg(2+), Zn(2+). However, the color changed to black transition when the GMDTC mixed with Cu(2+) and the color changed from yellow precipitate to light yellow transparent transition when GMDTC mix with Hg(2+). Moreover, the peak area as well as the retention time has changed a lot which indicated that a chemical reaction has already happened. When the GMDTC mixed with Cd(2+) and Pb(2+), the color has changed from pale yellow to colorless transparent and the peak area of GMDTC has increased a lot. Finally, the GMDTC-Cd complex ratio both of which are 2:1 were calculated based on the results of LC-MS instrument and atomic calculations. Conclusion: The specific cadmium chelating agent GMDTC can not react with the Ca(2+), Fe(2+), Mg(2+), Zn(2+), but it can react chemically with Cu(2+) and Hg(2+), even specific complex with Pb(2+) and Cd(2+).

[Influence of sodium nitrite exposure on sulfhemoglobin and hydroxyl radicals in mice].

Objective: To investigate the influence of sodium nitrite exposure on sulfhemoglobin and hydroxyl radicals in mice. Methods: A total of 60 mice were randomly divided into low-, middle-, and high-dose groups (the concentrations of sodium nitrite were 0.055 mg/ml, 0.110 mg/ml, and 0.220 mg/ml, respectively) and control group (treated with distilled water) , with 15 mice in each group (male/female ratio=1: 1) . A free-drink model was applied and the duration of exposure was 2 weeks. The body weight of all mice was recorded before exposure and at weeks 1 and 2 of exposure. At the end of exposure, the mice were treated with intraperitoneally injected sodium salicylate to capture the hydroxyl radicals and produce 2, 5-dihydroxybenzoic acid and 2, 3-dihydroxybenzoic acid, and high-performance liquid chromatography was used to measure their content. Spectrophotometry was used to measure the relative content of sulfhemoglobin. Results: At week 2 of exposure, the low-, middle-, and high-dose groups had significantly lower body weight than the control group (22.8±2.8 g/21.6±2.8 g/21.2±3.0 g vs 25.6±2.2 g, P<0.05) . The low-, middle-, and high-dose groups had a significantly higher total content of hydroxyl radicals than the control group[ (0.015 3±0.006 5) µg/ml, (0.016 4±0.017 2) µg/ml, and (0.062 7±0.091 0) µg/ml vs (0.009 ±0.007 3) µg/ml, P<0.05]. The relative content of sulfhemoglobin was 1.54%±0.73%, 2.22%±0.44%, and 2.80%±0.69%, respectively, in the low-, middle-, and high-dose groups, and the middle- and high-dose groups had a significant increase in the relative content of sulfhemoglobin compared with the control group (2.22%±0.44%/2.80%±0.69% vs 1.76%±0.60%, P<0.05) . The content of hydroxyl radicals was positively correlated with the relative content of sulfhemoglobin (r=0.837, P<0.05) . Conclusion: Sodium nitrite exposure can increase the content of sulfhemoglobin and hydroxyl radicals in blood, and there is a positive correlation between them.

Connexin 43 enhances oxaliplatin cytotoxicity in colorectal cancer cell lines.

Oxaliplatin, a platinum-based chemotherapeutic agent, is an important first-line drug in the treatment of colorectal cancers, but drug resistance causes treatment failure. It has been reported that gap junctional communication can enhance the cytotoxicity of platinum drugs.  The gap junction formed of connexin proteins provides a direct pathway for electrical and metabolic cell-cell interaction. The voltage-dependent gating of gap junction allows small hydrophilic molecules and ions to permeate to adjacent cells. Connexin 43 is a diagnostic marker for cancer therapy and the predominant connexin isoform in many cell types. The purpose of this study was to investigate the role of connexin 43 in oxaliplatin activity by using colorectal cancer cell lines. LoVo and HCT116 cell lines were used for analysis. Connexin 43 expression was confirmed by western blot and immunocytochemistry. MTT, western blot, "Parachute" dye-coupling assays and reactive oxygen species measurement were used to detect cytotoxicity and the inhibition of connexin 43 expression induced by oxaliplatin. Results showed that connexin 43 enhanced oxaliplatin cytotoxicity through gap junctional communication function and high concentration of oxaliplatin inhibited connexin 43 expression to counteract its cytotoxicity. This study suggested that connexin 43 could be considered a molecular target of oxaliplatin activity in colorectal cancer.

[Influence of n-hexane on vascular endothelial active substances in brain tissue in mice].

Objective: To investigate the influence of n-hexane on vascular endothelial active substances in brain tissue in mice and its significance. Methods: A total of 48 healthy Kunming mice were randomly divided into high-dose exposure group, middle-dose exposure group, low-dose exposure group, and control group, with 12 mice in each group. All groups except the control group were exposed to n-hexane via static inhalation (0.035 g/L, 0.018 g/L, and 0.009 g/L for the high-, middle-, and low-dose exposure groups, respectively) 4 hours a day for 21 days. the mice in the control groups were not exposed to n-hexane. After the exposure, the lev-els of endothelin-1 (ET-1) , nitric oxide (NO) , and angiotensin II (Ang II) in brain tissue were measured in all groups. Results: There were significant differences in the levels of ET-1, NO, and Ang II between the three ex-posure groups and the control group (P<0.05). Compared with the control group, the high-and middle-dose expo-sure group had significant increases in the levels of ET-1 and Ang II and the high-dose exposure group had a sig-nificant reduction in the level of NO (P<0.05 or P<0.01). Conclusion: n-Hexane can affect the vascular endothe-lial active substances in brain tissue in mice, and the changes and imbalance in vascular endothelial active sub-stances may be one of the reasons for central nervous system impairment caused by n-hexane.

[Effect of silica dust on protein oxidative injury in lung tissue of mice].

Objective: To investigate the effect of silica dust on protein oxidative injury in the lung tissue of mice. Methods: A total of 60 mice were randomly divided into control group (not exposed to dust) , 2-hour group (inhalation of dust for 2 hours per day) , 4-hour group (inhalation of dust for 4 hours per day) , and 8-hour group (inhalation of dust for 8 hours per day) , with 15 mice in each group. During dust exposure, the mice were placed in a dust exposure cabinet; the dust was blown with an air blower and the concentration was maintained at 125 mg/m(3). All mice were exposed to silica dust for 3 weeks. The changes of the lung were observed after dust exposure ended, and spectrophotometry was performed to measure the activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA) and protein carbonyl in the lung tissue. Results: The 2-, 4-, and 8-hour groups had marked edema, sporadic punctate hemorrhage, and nodular shadow in the lungs. Compared with the control group, the 2-, 4-, and 8-hour groups had a significant increase in lung coefficient (7.03±0.78 mg/g, 8.48±0.93 mg/g, and 8.99±0.85 mg/g vs 5.52±0.81 mg/g, P<0.05) . Compared with the control group, the 2-, 4-, and 8-hour groups had significant increases in the content of MDA (2.83±0.52, 3.94±0.65, and 4.56±0.77 nmol/mg prot vs 1.26±0.36 nmol/mg prot, P<0.05) and protein carbonyl (1.61±0.44, 1.96±0.47, and 2.20±0.58 nmol/mg prot vs 1.13±0.21 nmol/mg prot, P<0.05) in lung tissue. The 4- and 8-hour groups had a significantly lower activity of SOD than the control group (153.69±20.58 and 140.35±18.97 U/mg prot vs 186.00±25.46 U/mg prot, P<0.05) . Conclusions: Silica dust may lead to protein oxidative injury in the lung tissue of mice, which might play an important role in lung injury.

[Effects of expression of calpain mRNA in rabbits exposed to vibration by hind legs].

OBJECTIVE: To study the effects of expression of calpain mRNA in rabbits exposed to vibration by hind legs. METHODS: 32 New Zealand rabbits were randomly divided into a control group and 3 experimental groups according to 4-hour energy-equivalent frequency-weighted acceleration[ahw (4)]: low (4.33 m/s(2)) , moderate (8.67 m/s(2)) and high (17.34 m/s(2)) intensity group to accepted the vibration by hind legs. 45 ds later, brain and skeletal muscle tissue of rabbits were taken to detect the expression of calpain-1 and calpain-2 mRNA by RT-qPCR technique. RESULTS: The relative content of calpain-1 mRNA in the brain tissues in rabbits of low, medium and high intensity group were 8.35±3.75,9.64±4.54,5.10±5.26. While the relative content of calpain-2 mRNA in the brain tissues in rabbits of low, medium and high intensity group were 7.34±4.97,8.50±5.66, 8.16±5.59. Compared with the control group (1.10±0.29, 0.56±0.43) , the expression of calpain-1 and calpain-2 mRNA of the intensity groups showed an significantly increasing trend (P<0.01). In skeletal muscle tissue, the relative content of calpain-1 mRNA were 4.36±2.05, 7.37±4.06, 12.46±6.21.Compared with the control group (0.98±0.59) , the expression of calpain-1 mRNA of experiment groups were significantly higher (P<0.05) .The expression of calpain-2 mRNA of the intensity groups had no significantly difference with the control group (P>0.05). CONCLUSION: The expression of calpain-1 and calpain-2 mRNA can be promoted by the vibration by the hind legs.

Co-suppression of vitamin C composite nano-drug carrier and its drug delivery to nidus in tumor cells.

This study aimed to discuss the co-suppression of vitamin C-contained composite nano-drug carrier and its drug delivery to nidus in tumor cells. Amphiphilic polymers PLA-block-PAAA and block polymer PLA-PEG4000-Maleimide, PLA-block-PAAA and PLA-PEG4000-Maleimide composite nano-micelles were prepared, and, PLA-block-PAAA polymer-coated Nile red nano-micelle, PLA-block-PAA and PLA-PEG4000-Maleimide composite nano-micelles as well as paclitaxel-carrying composite nano-micelle in different molar ratios were given stability tests. Lastly, PLA-block-PAAA and PLA-PEG4000-Maleimide composite nano-micelle cancer cells and paclitaxel-carrying composite nano-micelle cancer cells were given toxicity tests. Stability tests showed that self stability of PLA-block-PAAA (63/8) nano-micelle was not sufficient; the stability was good when the molar ratio of PLA-block-PAAA and PLA-PEG4000-Maleimide composite nano-micelle was 3:1; paclitaxel-carrying composite nano-micelle had good stability within 48 hours; PAAA segment had an inhibiting effect on C6 cancer cells and paclitaxel-carrying composite nano-micelle had a strong inhibiting effect also on tumors. After 24 hours, with the continuous release of paclitaxel, the tumor inhibiting effect of paclitaxel-carrying composite nano-micelle enhanced gradually, and the controlled-release of drugs had continuous inhibiting effect on tumor cells. Therefore, PAAA segment and paclitaxel had time-postponed synergistic effect. In conclusion, vitamin C-contained composite nanometer drug carrier materials can deliver anti-cancer drugs to nidus and thus inhibit tumor cells.

ATAD2 is overexpressed in gastric cancer and serves as an independent poor prognostic biomarker.

OBJECTIVE: ATPase family, AAA domain containing 2 (ATAD2) has been found overexpressed in various cancer types and correlated with malignant status and poor prognosis. However, little is known about the clinical significance of ATAD2 in gastric cancer patients. The aim of this study was to explore the clinical and prognostic significance of ATAD2 in gastric cancer. METHODS: The mRNA and protein levels expression of ATAD2 were detected in clinical tissue samples by qRT-PCR and immunohistochemistry, respectively. We examined the ATAD2 protein expression by immunohistochemistry. Furthermore, we analyzed the association between ATAD2 expression and clinicopathological features including prognosis in 166 gastric cancer samples. RESULTS: In our results, ATAD2 mRNA and protein were highly expressed in gastric cancer samples. ATAD2 overexpression was correlated with advanced clinical stage, tumor depth, lymph node metastasis, and distant metastasis. According to the survival analysis, ATAD2 protein overexpression was a poor independent prognostic factor for gastric cancer patients. CONCLUSIONS: In summary, ATAD2 could serve as a prognostic biomarker for gastric cancer patients.

miR-625 suppresses tumour migration and invasion by targeting IGF2BP1 in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies and the third leading cause of cancer-related deaths worldwide. Tumour metastasis is one of the major causes of high mortality. microRNAshave been implicated in HCC metastasis. In this study, we found that miR-625 was frequently downregulated in HCC samples. A decrease in miR-625 was significantly correlated with lymph node anddistance metastasis (P=0.013), the presence of portal venous invasion (P=0.036), tumor-node-metastasis (TNM) stage (P=0.027) and unfavourable overall survival (P=0.003). Compared with primary tumours, miR-625 expression was markedly reduced in portal venous metastatic tumours. Re-expression of miR-625 in HCC cells was remarkably effective in suppressing cell migration andinvasiveness in vitro and in vivo. Mechanistically, miR-625 was confirmed to downregulate IGF2 mRNA-binding protein 1(IGF2BP1) directly, the expression of which was inversely correlated with the level of miR-625 in HCC cell lines and tissues. High expression of IGF2BP1 was frequently found in HCC samples, and associated with poor prognosis. Knockdown of endogenous IGF2BP1 by siRNA exhibited similar effects as the overexpression of miR-625, whereas overexpression of IGF2BP1 (without the 3'-UTR) abrogated miR-625-mediated metastasis inhibition. Interference of the PTEN/HSP27 pathway contributed to miR-625-mediated metastasis inhibition. Taken together, our data suggest that miR-625 might function as an antimetastatic miRNA to have an important role in HCC progression by modulating the IGF2BP1/PTEN pathway. The newly identified miR-625/IGF2BP1 axis represents a new potential therapeutic target for HCC treatment.

Genetic polymorphisms of CCND1 and PTEN in progression of esophageal squamous carcinoma.

Cyclin D1 (CCND1) plays a significant role in G1-S transition of cell cycle, and phosphatase and a tensin homologue (PTEN) negatively regulate cell cycle through phosphatidylinositol 3-kinase (PI3K)/AKT signaling. CCND1 and PTEN genetic polymorphisms might induce susceptibility to the occurrence of esophageal squamous cell carcinoma (ESCC). Three hundred and four ESCC patients and 413 healthy controls from Anyang, China, were enrolled in this study. All genotyping at CCND1 (807 G/A) and PTEN (rs701848 T/C and rs2735343 C/G) were identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Unconditional logistic regression model was used to analyze the correlation between the polymorphisms and the susceptibility to develop ESCC. Statistically significant differences were observed between cases and controls in distribution of genotypes or alleles at PTEN rs701848 T/C and rs2735343 C/G, with either haplotype TG or CG possessing notably higher proportion in cases than in the controls. However, such difference could not be found in the distribution of the polymorphisms at CCND1 807 G/A. In summary, the polymorphisms of PTEN rs701848 T/C and rs2735343 C/G might represent crucial modifying factors for development of ESCC.

Selection of peptide inhibitors for double-stranded RNA-dependent protein kinase PKR.

Protein kinase inhibitors have been developed and applied as antitumor drugs. The majority of these inhibitors are derived from ATP analogs with limited specificity towards the kinase target. Here we present our proof-of-principle study on peptide inhibitors for kinases. Two peptides were selected by phage display against double-stranded RNA-dependent protein kinase (PKR). In vitro assay revealed that these peptides exhibit an inhibitory effect on PKR-catalyzed phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF2α). The peptides also interrupt PKR activity in cells infected by viruses, as PKR activation is one of the hallmarks of host response to viral infection. Kinetic study revealed that one of the peptides, named P1, is a competitive inhibitor for PKR, while the other, named P2, exhibits a more complicated pattern of inhibition on PKR activity. Fragment-based docking of the PKR-peptide complex suggests that P1 occupies the substrate pocket of PKR and thus inhibits the binding between PKR and eIF2α, whereas P2 sits near the substrate pocket. The computational model of PKR-peptide complex agrees with their kinetic behavior. We surmise that peptide inhibitors for kinases have higher specificity than ATP analogs, and that they provide promising leads for the optimization of kinase inhibitors.

Potential implication of activating killer cell immunoglobulin-like receptor and HLA in onset of pulmonary tuberculosis.

Killer cell immunoglobulin-like receptor (KIR) and human leucocyte antigen (HLA) play crucial role in maintaining immune homoeostasis and controlling immune responses. To investigate the influence of KIR and HLA-C ligands on the risk of pulmonary tuberculosis (PTB), we studied 200 patients who were confirmed to have PTB and 200 healthy controls on the different frequencies of KIR and HLA-C ligands. Genotyping of these genes was conducted by sequence-specific primer polymerase chain reaction (SSP-PCR) method. Gene frequencies were compared between PTB group and the control group by χ(2) test, and P < 0.05 was regarded as statistically significant. As a result, the frequency of KIR genotype A/B was increased in PTB than controls but A/A was decreased. Moreover, striking differences were observed in the frequencies of HLA-Cw*08 between the two groups. Besides, the frequencies of '2DL2/3 with C1' in PTB were increased compared with control group. In addition, individuals with no KIR2DS3 and no Cw*08 were higher in controls than in PTB. KIR2DS1 was increased in PTB when HLA-C group 2 alleles were missing. In conclusion, KIR and HLA-C gene polymorphisms were related to susceptibility to PTB.