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BACKGROUND: Brain metastasis is an important cause of increased mortality in patients with non-small cell lung cancer (NSCLC). In brain metastasis, the blood-brain barrier (BBB) is frequently impaired, forming blood-tumor barrier (BTB). The efficacy of chemotherapy is usually very poor. However, the characteristics of BTB and the impacts of BTB on chemotherapeutic drug delivery remain unclear. The present study investigated the structure of BTB, as well as the distribution of routine clinical chemotherapeutic drugs in both brain and peripheral tumors. METHODS: Bioluminescent image was used to monitor the tumor load after intracranial injection of lung cancer Lewis cells in mice. The permeability of BBB and BTB was measured by fluorescent tracers of evans blue and fluorescein sodium. Transmission electron microscopy (TEM), immunohistochemistry and immunofluorescence were performed to analyze structural differences between BBB and BTB. The concentrations of chemotherapeutic drugs (gemcitabine, paclitaxel and pemetrexed) in tissues were assayed by liquid chromatography with tandem mass spectrometry (LC-MS/MS). RESULTS: Brain metastases exhibited increased BTB permeability compared with normal BBB detected by fluorescence tracers. TEM showed abnormal blood vessels, damaged endothelial cells, thick basement membranes, impaired intercellular endothelial tight junctions, as well as increased fenestrae and pinocytotic vesicles in metastatic lesions. Immunohistochemistry and immunofluorescence revealed that astrocytes were distributed surrounded the blood vessels both in normal brain and the tumor border, but no astrocytes were found in the inner metastatic lesions. By LC-MS/MS analysis, gemcitabine showed higher permeability in brain metastases. CONCLUSIONS: Brain metastases of lung cancer disrupted the structure of BBB, and this disruption was heterogeneous. Chemotherapeutic drugs can cross the BTB of brain metastases of lung cancer but have difficulty crossing the normal BBB. Among the three commonly used chemotherapy drugs, gemcitabine has the highest distribution in brain metastases. The permeability of chemotherapeutic agents is related to their molecular weight and liposolubility.
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Objective@#To understand the prevalence of hepatitis C virus ( HCV ) infection in sentinel surveillance in Liaoning Province from 2015 to 2019, in order to provide evidence for the precise prevention and control of HCV.@*Methods@#The HCV sentinel surveillance data of 5 kinds of populations, including dialyzed patients, patients receiving invasive diagnosis and treatment, family planning outpatients, people receiving physical examination and unpaid blood donators in Liaoning Province from 2015 to 2019 were retrieved, and the HCV positive rates of different years, gender and age groups in the five populations were analyzed. @*Results@#There were 26 000 persons surveyed and 61 HCV positive cases were detected from 2015 to 2019. The HCV positive rate was 0.23%. The HCV positive rates of dialyzed patients, patients receiving invasive diagnosis and treatment, family planning outpatients, people receiving physical examination and unpaid blood donators were 0.40%, 0.70%, 0.25%, 0.24% and 0.14%, respectively. The HCV positive rates of dialyzed patients, patients receiving invasive diagnosis and treatment, and unpaid blood donators had significant downward trends ( P<0.05 ). The HCV positive rates of males and females were 0.22% and 0.26%, without any significant difference ( P>0.05 ). The HCV positive rate of people aged above 70 years old was 1.15%, the highest among different age groups. @*Conclusions@#The prevalence of HCV infection among the patients with hemodialysis and with invasive diagnosis and treatment is relatively high. The level of HCV antibody of older age groups should be monitored regularly.
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To make an genetic analysis of starch branching enzyme (Q enzyme) inheritance, which is important in catalyzing the formation of amylopectin and thereby raising the amylopectin/amylose ratio of starch in rice grains, a linkage map of 207 DNA markers were constructed by using 247 recombinant inbred lines derived from an indica-indica rice cross Zhenshan 97B/Milyang46. In 2002 and 2003, the activities of starch branching enzyme of the parents and 247 RILs were measured 10 d and 20 d respectively after flowering (Table 1). A total of 3 quantitative trait loci (QTLs) were detected to have significant additive effects on Q enzyme activities 10 d after flowering with 10% phenotypic variations explained for the three QTLs (Table 2, Fig.1). Meanwhile, qQ10-6 with significant QTL x environment interaction was detected. Epistasis analysis detected 5 and 2 significant additive-by-additive interactions for Q enzyme 10 d and 20 d respectively after flowering (Table 3), and three pairs of QTLs 10 d after flowering with significant epistasis x environment interactions were detected, explaining 3% to 12% of the phenotypic variation. The results showed that the environmental factors had obvious effect on the gene expression of Q enzyme activity in rice grain. Meanwhile, the location of qQ10-6 in relation to that of QTLs for gelatinization temperature, gene loci involved in ADPG pyrophosphorylase and soluble starch synthase were discussed with the help of a genetic map.