Objective Many environmental epidemiological studies have shown the associations between short-term exposure of air pollution and daily deaths.However,the generally available population data only contain a small number of measured confounding factors,which is faced with the problem that a large number of unobserved confounding factors are not included in the model,resulting in biased estimates.The instrumental variable method can solve the problem of estimating the effects caused by unobserved confounders.In this paper,We used the instrumental variable method to estimate the effects of PM2.5 on daily mortality.Methods We collected daily PM2.5 concentrations,meteorological data,and nonaccidental daily deaths in a Chinese city from 2016 to 2019.We used boundary layer height and wind speed as instrumental variables to estimate the effects of PM2.5 on nonaccidental daily mortality.Negative exposure control was used to test the hypothesis of instrumental variables.Meanwhile time series bootstrap method was used to estimate confidence interval.We compared the results of the generalized additive model and instrumental variable method.Results The instrumental variable method showed that PM2.5 was significantly related to daily deaths.For every 10 μg/m3 increase of PM2.5 concentrations,the nonaccidental daily deaths increased by 0.94%(95%CI:0.39%～1.55%).Negative exposure control results showed no correlation between negative exposure and nonaccidental deaths(P=0.19),indicated that the aforementioned instrumental variable model was not affected by unmeasured and uncontrolled confounders.The traditional generalized additive model estimated that for every 10 μg/m3 increase in PM2.5 concentrations,the nonaccidental deaths would increase by 0.24%(95%CI:0.01%～0.47%).Conclusion The instrumental variable method estimated that PM2.5 concentrations were significantly correlated with the nonaccidental daily deaths.Boundary layer height and wind speed can be used as instrumental variables to estimate the effects of PM2.5 concentrations on nonaccidental deaths.

Objective:To investigate the expression of cancer-associated fibroblasts(CAFs) marker proteins in papillary thyroid carcinoma(PTC) using immunohistochemistry and explore their correlation with clinicopathological characteristics.Methods:The clinicopathological data of 90 PTC patients at Tianjin Medical University General Hospital from December 2019 to January 2021 were retrospectively analyzed. Surgical pathological cancer tissue samples were selected for immunohistochemical staining, and control group tissues were obtained from normal thyroid tissue adjacent to the tumor lesion. Four CAFs marker proteins, including fibroblast-activated protein(FAP), α-smooth muscle actin(α-SMA), Vimentin, and platelet-derived growth factor receptor-α(PDGFR-α), were stained and scored, followed by statistical analysis.Results:The immunoreactivity score of the CAFs marker proteins were correlated with extrathyroid invasion, lymph node metastasis, and multi-focality of PTC. FAP and α-SMA demonstrated better performance in this regard. Multivariate logistic regression analysis and receiver operating characteristic(ROC) curve analysis showed that high immunoreactivity scores of FAP and α-SMA were risk factors for poor clinical pathological features, with good predictive sensitivity and accuracy.Conclusion:Strong expression of CAFs was the risk factor for extrathyroid invasion, lymph node metastasis, and mutli-focality of PTC. FAP has the highest clinical value compared with other CAFs marker proteins.

Essential fatty acids are those that could not be synthesized by the body itself but crucial for health and life. Studies have shown that ω-3 fatty acids may facilitate human physiological functions. Mammals lack ω-3 desaturase gene, and the Δ15 fatty acid desaturase (Δ15 Des) from Caenorhabditis elegans can transform the ω-6 polyunsaturated fatty acids (PUFAs) into ω-3 PUFAs. Transgenic mice expressing Δ15 Des enzyme activity was constructed by using a PiggyBac transposon (PB). Homozygous transgenic mice with stable inheritance was bred in a short time, with a positive rate of 35.1% achieved. The mice were fed with 6% ω-6 PUFAs and the changes of fatty acids in mice were detected by gas chromatography (GC). The expression level of Δ15 Des in mice was detected by quantitative PCR (qPCR) and Western blotting (WB). qPCR and GC analysis revealed that the percentage of positive mice harboring the active gene was 61.53%. Compared with traditional methods, the transformation efficiency and activity of Δ15 Des were significantly improved, and homozygotes showed higher activity than that of heterozygotes. This further verified the efficient transduction efficiency of the PiggyBac transposon system.
Animals ; Caenorhabditis elegans/genetics* ; Fatty Acid Desaturases/genetics* ; Fatty Acids ; Fatty Acids, Omega-3 ; Mice ; Mice, Transgenic

Very long chain polyunsaturated fatty acids (VLC-PUFAs) are unique fatty acids in tissues of mammals such as retina and testis, and the key enzyme of its biosynthesis is very long chain fatty acid elongase 4 (Elovl4). Development of an animal model of tissue-specific knockout of Elovl4 gene is conducive to the in-depth study of the biological function of VLC-PUFAs. Therefore, we constructed Stra8-Cre mice and Elovl4 floxed mice based on Cre/loxP system, and obtained the (Elovl4[flox/+], Stra8-Cre) heterozygous knockout mice by hybridization. Subsequently, female mice were selected to cross with male mice with homozygous Elovl4[flox/flox] to gain homozygous mice (Elovl4[flox/flox], Stra8-Cre) through genotype identification and screening. RT-PCR, qRT-PCR, Western blotting, immunohistochemistry and immunofluorescence techniques were used to detect the knock-out efficiency of Elovl4 in testis. The expression of Elovl4 in testis of both heterozygous and homozygous knockout mice were significantly down-regulated at mRNA and protein levels, but were not affected in other tissues. In summary, we constructed a mouse model with specific knockout of Elovl4 gene in testis, which provides a reliable animal model for studying the effect of VLC-PUFAs on the reproductive function of male mice and the underpinning molecular mechanisms.
Animals ; Disease Models, Animal ; Eye Proteins/metabolism* ; Female ; Gene Knockout Techniques ; Integrases ; Male ; Mammals/metabolism* ; Membrane Proteins/metabolism* ; Mice ; Mice, Knockout ; Testis/metabolism*

Quench of magnetic resonance imaging system refers to the process that the superconducting condition inside the magnet is destroyed due to some reason. The large current stored in the coil is quickly converted into heat at the place where the resistance is formed, and a large amount of liquid helium in the magnet is evaporated. If it happens, it will cause huge loss to the user. We introduce the real cases of 1.5 T magnetic resonance imaging system's quench fault, maintenance treatment and management improvement, which can be used for reference by various medical institutions, so as to better strengthen the operation and maintenance management of magnetic resonance imaging system, so as to avoid the occurrence of out of tolerance fault, and do a good job in the guarantee work after the out of tolerance fault.
Helium ; Magnetic Resonance Imaging ; Magnets

The transposon vector containing enhanced green fluorescent protein (EGFP) was injected into early housefly (Musca domestica L.) eggs by microinjection method to realize stable gene expression in vivo for verification, and to study housefly gene function. A borosilicate glass micro injection needle suitable for microinjection of housefly eggs was made, the softening treatment conditions of housefly egg shells were explored, and a microinjection technology platform suitable for housefly was constructed with a high-precision microsyringe Nanoject Ⅲ as the main body. The recombinant plasmid PiggyBac-[3×P3]-EGFP containing the eye-specific 3×P3 promoter and EGFP and the stable genetic expression helper plasmid pHA3pig helper were microinjected into the treated housefly eggs. After emergence, the eye luminescence was observed, and the expression and transcription level of EGFP were detected. The results showed that the normal hatching rate of housefly eggs was 55% when rinsed in bleaching water for 35 s. The hardness of the egg shell treated for 35 s was suitable for injection and the injection needle was not easy to break. About 3% of the emerged housefly eyes had green fluorescence. Through further molecular detection, EGFP specific fragments with a size of 750 bp were amplified from DNA and RNA of housefly. Through the technical platform, the stable expression of reporter genes in housefly can be conveniently and effectively realized, and a bioreactor with housefly as the main body can be established, which provides certain reference value for subsequent research on housefly gene function.
Animals ; Animals, Genetically Modified ; Gene Expression ; Genes, Reporter ; Green Fluorescent Proteins/genetics* ; Houseflies/genetics* ; Microinjections

In most insects, polyunsaturated fatty acids (PUFAs) are mainly polyunsaturated fatty acids with a carbon-chain length less than 18 carbon atoms, hardly any long-chain polyunsaturated fatty acids such as C20 and C22 that are more valuable and bioactive. This study, by using Drosophila melanogaster (Fruit fly) as a model organism, optimized the Δ6-fatty acid elongase enzyme Elovl5 gene from mice and transferred it to fruit flies for expression. Vectors containing Elovl5 gene were successfully injected into drosophila embryo through the microscopic injection. There were enhanced green fluorescent proteins expressed in the whole developmental stage of Drosophila be means of fluorescence microscope. At the same time, expression of Elovl5 gene significantly contributed to the transformation of fruit flies C18-polyunsaturated fatty acids in the body towards the biosynthesis of longer-chain polyunsaturated fatty acids. The transgenic fruit fly model rich in long-chain polyunsaturated fatty acids such as C20 and C22 were obtained, providing a basis for further research on biosynthesis of polyunsaturated fatty acids in fruit flies.
Acetyltransferases/genetics* ; Animals ; Drosophila melanogaster/genetics* ; Fatty Acid Elongases/metabolism* ; Fatty Acids/genetics* ; Gene Transfer Techniques ; Mice

In order to study the significance of CD276 and CD133 in the development and progression of colorectal cancer (CRC),the expression of CD276 and CD133 was detected by immunohistochemistry in CRC and precancerous lesions.The results showed that the intensity of CD276 and CD133 in CRC samples was higher than that in adenoma group and non-adenoma group.CD276 and CD133 single and double positive expression were significantly correlated with CRC lymph node metastasis,distant metastasis and survival.CD276 and CD133 are significantly correlated to the development and progression of CRC and associated with poor prognosis.

DHA (22:6n-3) is a Ω-3 polyunsaturated fatty acid with 22 carbon atoms and 6 double bonds, which has important biological functions in human body. Human and other mammals synthesize only limited amounts of DHA, more requirements must be satisfied from food resources. However, the natural resources of DHA (Mainly deep-sea fish and other marine products) are prone to depletion. New resources development is still insufficient to satisfy the growing market demand. Previous studies have revealed that the mammals can increase the synthesis of DHA and other long-chain polyunsaturated fatty acids after transgenic procedures. In this study, mammalian cells were transfected with Δ6, Δ5 desaturase, Δ6, Δ5 elongase, Δ15 desaturase (Isolated from nematode Caenorhabditis elegans) and Δ4 desaturase (Isolated from Euglena gracilis), simultaneously. Results show that the expression or overexpression of these 6 enzymes is capable of conversion of the o-6 linoleic acid (LA, 18:2n-6) in DHA (22:6n-3). DHA content has increased from 16.74% in the control group to 25.3% in the experimental group. The strategy and related technology in our research provided important data for future production the valuable DHA (22:6n-3) by using genetically modified animals.
Animals ; Caenorhabditis elegans ; enzymology ; Cells, Cultured ; Docosahexaenoic Acids ; chemistry ; Euglena gracilis ; enzymology ; Fatty Acid Desaturases ; biosynthesis ; Linoleic Acid ; chemistry ; Mammals ; Transfection

OBJECTIVETo evaluate the alterations in renal function after radical nephrectomy (RN) and partial nephrectomy (PN) for renal cell carcinoma (RCC) and to determine the risk factors for the onset of postoperative renal function impairment.

METHODSWe assessed the renal function of 429 T1a RCC patients by investigating the time-dependent changes of the estimated glomerular filtration rate (eGFR) after surgery from August 2003 to August 2010. Univariate and multivariate regression models were used to determine the risk factors for the onset of an eGFR < 60 ml · min⁻¹ · 1.73 m⁻² function, and to evaluate the prognosis for the two groups.

RESULTSThe mean eGFR values (ml · min⁻¹ · 1.73 m⁻²) at postoperative 1, 7 days, 1, 3, 6, 12 and 24 months were 51.4 ± 12.6, 52.1 ± 17.8, 53.2 ± 19.5, 54.6 ± 20.2, 53.8 ± 16.6, 52.7 ± 22.3 and 51.5 ± 18.4 in the RN group and 69.6 ± 18.3, 70.3 ± 19.5, 71.5 ± 21.4, 76.2 ± 22.8, 75.4 ± 19.7, 74.3 ± 16.3 and 73.1 ± 23.2 in the PN group, respectively. The eGFR of the radical nephrectomy group was significantly lower than that of the partial nephrectomy group (P < 0.05). Multivariable analysis revealed that radical nephrectomy and age were risk factors for the onset of postoperative chronic renal dysfunction.

CONCLUSIONSRenal function recovered partially after partial and radical nephrectomy and is maintained constantly after 3 months. Surgical mode and age are risk factors for the onset of postoperative eGFR < 60 ml · min⁻¹ · 1.73 m⁻² impairment. Compared with radical nephrectomy, partial nephrectomy can preserve renal function and reduce the incidence of postoperative chronic renal dysfunction.

Age Factors ; Carcinoma, Renal Cell ; pathology ; physiopathology ; surgery ; Glomerular Filtration Rate ; Humans ; Kidney Neoplasms ; pathology ; physiopathology ; surgery ; Nephrectomy ; adverse effects ; methods ; Postoperative Complications ; physiopathology ; Postoperative Period ; Renal Insufficiency, Chronic ; etiology ; physiopathology ; Risk Factors