Programmable hyperbolic polaritons in van der Waals semiconductors

Collective electronic modes or lattice vibrations usually prohibit propagation of electromagnetic radiation through the bulk of common materials over a frequency range associated with these oscillations. However, this textbook tenet does not necessarily apply to layered crystals. Highly anisotropic materials often display nonintuitive optical properties and can permit propagation of subdiffractional waveguide modes, with hyperbolic dispersion, throughout their bulk. Here, we report on the observation of optically induced electronic hyperbolicity in the layered transition metal dichalcogenide tungsten diselenide (WSe₂). We used photoexcitation to inject electron-hole pairs in WSe₂ and then visualized, by transient nanoimaging, the hyperbolic rays that traveled along conical trajectories inside of the crystal. We establish here the signatures of programmable hyperbolic electrodynamics and assess the role of quantum transitions of excitons within the Rydberg series in the observed polaritonic response.

Long non-coding RNA PVT1 regulates glioma proliferation, invasion, and aerobic glycolysis via miR-140-5p

OBJECTIVE

To investigate the regulation of long non-coding RNA plasmacytoma variant translocation 1 (LncRNA PVT1) on proliferation, invasion, and aerobic glycolysis in glioma cells via miR-140-5p.

PATIENTS AND METHODS

Sixty patients with glioma treated in our hospital were recruited. The expression of PVT1 in tissues and cells was determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR), and the effects on the prognosis were observed. Glioma cell lines U87 and T98MG were either stably or transiently transfected with over-expression or inhibition vectors. Cell counting kit-8 (CCK-8), transwell, glucose, and lactate detection were employed to measure cell proliferation, invasion, and aerobic glycolysis after transfection. The correlation between PVT1 and miR-140-5p was determined by Dual-Luciferase reporter assay. RNA pull-down and RNA immunoprecipitation (RIP) test were adopted to indicate the correlation between PVT1 and miR-140-5p.

RESULTS

PVT1 was highly expressed and had superior diagnostic value in gliomas, and the high expression of PVT1 resulted in poor prognosis of patients. Over-expressing PVT1 increased cell proliferation, invasion, and aerobic glycolysis, while inhibiting PVT1 yielded opposite outcome. Dual-Luciferase reporter assay confirmed that PVT1 could target miR-140-5p. Functional analysis showed that over-expression of miR-140-5p inhibited proliferation, invasion, and aerobic glycolysis in glioma cells. Rescue experiment found that the inhibitory effect of miR-140-5p could be eliminated by up-regulating PVT1 expression.

CONCLUSIONS

PVT1 promotes proliferation, invasion, and aerobic glycolysis in glioma cells by regulating miR-140-5p.

Delayed seroreversion of specifical antibody against HIV in HIV-exposed infants: A retrospective cohort study

OBJECTIVES

To investigate the seroreversion time in HIV-1-exposed but uninfected infants from two tertiary hospitals in China.

METHODS

This study retrospectively investigated the data of perinatal, HIV-1-exposed infants from hospitals in Beijing and Shenzhen. Maternal and infant medical records from both hospitals from January 2009 to December 2019 were reviewed, and the HIV antibody seroreversion times of infants were determined. From 2009 to 2019, a total of 485 HIV-1-exposed but uninfected infants were enrolled. The majority of infants were born at term with normal birth weight.

RESULTS

The seroreversion rates were 89.3%, 94.2% and 100% at 12, 18 and 24 months of age, respectively. There were no significant associations between seroreversion and several risk factors, such as gender, birth weight, gestational age, mode of delivery, postpartum prophylaxis and antiretroviral treatment duration. The mean value of HIV-specific immunoglobulin G concentration decreased from 15.4 at day 42 to 0.03 after 24 months in HIV-exposed, uninfected infants.

CONCLUSIONS

Clearance of HIV antibodies could take more than 18 months in a small number of perinatally exposed infants. Caution should be used in excluding or diagnosing perinatal HIV infection in children with long persistence of HIV antibodies.

[Research status and prospect on autologous tissue-engineered skin as permanent graft]

To date, skin substitute that can provide permanent wound closure is still autologous tissue-engineered skin using autologous skin cells as seed cells. The development of cultured epithelial autograft has experienced a long and tortuous process. Autologous tissue-engineered composite skin is closer to autologous split-thickness skin graft in terms of structure, function, and efficacy, which has become a research focus in recent years. Based on the actual status of research on tissue-engineered skin application, this paper reviewed the main research progresses and existing problems, and the prospect of research and development and clinical application of autologous tissue-engineered skin as permanent graft in order to provide a reference for the improvement and application of autologous tissue-engineered skin.

Genetic signature of hybridization between Chinese spot-billed ducks and domesticated ducks

In this study, we analyzed 93 whole genomes from Chinese spot-billed ducks (CSB), meat-type ducks (MET), and egg and dual purpose-type ducks (EDT) to characterize the genetic material flowing between the CSB and modern ducks. Using a frequency of shared identical-by-descent method, approximately 10.9 Mb introgression segments containing 140 genes were identified showing the signatures of introgression between CSB and EDT. Meanwhile, nearly 10.6 M introgression regions containing 149 genes were identified between CSB and MET. Based on the haplotypes tree of each segment, we found that the introgression between CSB and domesticated ducks was asymmetric with a high level of gene flow from domestic to CSB and a low level of migration in the opposite direction. Moreover, we identified several genes that were introgressions from CSB and showed the signature of positive selection, which may contribute to the breeding of modern ducks. Our results provide new insight into the evolution and breeding history of domestic ducks and may be useful for the future management of wild and domestic duck populations.

[Safety and immunogenicity analysis of recombinant （hansenula polymorpha) hepatitis B vaccine （CpG ODN adjuvant) among adults: the preliminary results of phase I clinical trial]

Objective: To evaluate the safety and immune effect of recombinant hepatitis B vaccine （CpG ODN adjuvant). Methods: On Oct. 26, 2016, we launched volunteer recruitment in Kaihua county, Quzhou city, Zhejiang Province. In the randomized, double-blind, controlled trial, a total of 48 subjects with negative HBV screening tests and normal hepatorenal function among 18 and 60 years old were selected and divided into two groups randomly, 24 cases each. The experimental group was given 250 μg of CpG ODN recombinant （Hansenula polymorpha) Hepatitis B vaccine and the control group was given 10 μg of commercial Hepatitis B vaccine with timed at 0, 1and 6 months. The inoculation reactions were compared the difference between the two groups after observed and recorded in time periods. We also collected serum before and after immunization to compare the two groups of anti-HBs positive rate, geometric mean concentration（GMC). Results: During the study period, the incidence of adverse events was 66.67%（16/24) in the experimental group and 54.17%（13/24) in the control group, with no significant difference（P=0.556). The severities of adverse events were level 1 or level 2, and no level 3 or above adverse reactions occurred. After full-course immunization, in the FAS data set, the anti-HBs GMC in the experimental group [2 598.56（1 127.90-5 986.90) mIU/ml] was higher than that in the control group[371.97（164.54-840.91) mIU/ml] In the PPS set, the GMC of test group was 7 808.21（3 377.00-18 052.00) mIU/ml, which was higher than that of the control group [843.22（213.80-3 325.90) mIU/ml]. The anti-HBs positive rate of FAS（PPS) was 95.83%（100.00%) in the experimental group and the control group; The anti-HBs strongly positive rate of FAS（PPS) was 79.17%（90.00%) in the experimental group and 33.33%（50.00%) in the control group, with statistically significant differences among the FAS set（P=0.003) and no statistically significance differences among the PPS set（P=0.074). Conclusion: CpG Hepatitis B Vaccine is safe and shows better immunogenicity than the control vaccine.

Melatonin inhibits the inflammation and apoptosis in rats with diabetic retinopathy via MAPK pathway

OBJECTIVE

To investigate the effect of melatonin on diabetic retinopathy rats through the mitogen-activated protein kinase (MAPK) pathway.

MATERIALS AND METHODS

A total of 48 Sprague Dawley (SD) rats were randomly divided into normal group (n=12), model group (n=12), melatonin group (n=12), and inhibitor group (n=12). The rats in normal group received no treatment. Those in model group, melatonin group, and inhibitor group were prepared into models of diabetic retinopathy and intraperitoneally injected with normal saline, melatonin, and SB 203580, respectively. After 7 days of intervention, the materials were taken. The expressions of B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) were detected through immunohistochemistry. Western blotting was employed to determine the protein expression levels of p38 MAPK, phosphorylated (p)-p38 MAPK, and cysteinyl aspartate specific proteinase-3 (Caspase-3). The messenger ribonucleic acid (mRNA) expression levels of Bax and Bcl-2 were measured via quantitative Polymerase Chain Reaction (qPCR). Enzyme-linked immunosorbent assay (ELISA) was performed to detect the levels of serum interleukin-1β (IL-1β) and IL-18. The apoptosis was determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling (TUNEL).

RESULTS

Based on immunohistochemistry, model group, melatonin group, and inhibitor group exhibited significantly increased positive expression of Bax but notably decreased positive expression of Bcl-2 in comparison with normal group (p<0.05). Compared with those in model group, the positive expression of Bax was clearly reduced, while the positive expression of Bcl-2 was overtly raised in melatonin group and inhibitor group (p<0.05). The results of Western blotting showed that there was no difference in the protein expression of p38 MAPK among all groups (p>0.05). Compared with normal group, the other three groups had remarkably elevated protein expressions of p-p38 MAPK and Caspase-3 (p<0.05). The protein expressions of p-p38 MAPK and Caspase-3 in melatonin group and inhibitor group were significantly lower than those in model group decreased (p<0.05). QPCR assay revealed that the mRNA expression of Bax was markedly lower in normal group than that in the other three groups, while the mRNA expression of Bcl-2 was significantly higher in normal group than that in the other three groups (p<0.05). Compared with model group, melatonin group, and inhibitory group showed clearly declined mRNA expression level of Bax and notably increased mRNA expression level of Bcl-2 (p<0.05). TUNEL results revealed that the apoptosis rate was remarkably elevated in the other three groups compared with that in normal group (p<0.05). In comparison with model group, melatonin group and inhibitor group exhibited significantly reduced apoptosis rate (p<0.05).

CONCLUSIONS

Melatonin inhibits the inflammation and apoptosis in rats with diabetic retinopathy by repressing the MAPK pathway.

MicroRNA-145 inhibits proliferation and promotes apoptosis of HepG2 cells by targeting ROCK1 through the ROCK1/NF-κB signaling pathway

OBJECTIVE

Hepatocellular carcinoma (HCC) is a malignant cancer with a high fatality rate, and the expression of microRNA-145 (miR-145) is significantly low in HCC tissue. Therefore, the effect of miR-145 on HCC was explored.

PATIENTS AND METHODS

Primary hepatocellular carcinoma samples and corresponding normal samples, and HepG2 cells were analyzed using flow cytometry, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Real-time quantitative reverse transcription-polymerase chain reaction, Western blotting, and dual-luciferase reporter assay.

RESULTS

miR-145 expression was significantly downregulated in HCC tissue and HepG2 cells as compared to normal liver tissue. After HepG2 cells were transfected with miR-145 mimics, miR-145 expression was recovered, accompanied by a significantly lower cell number, inhibition of the G1/S phase transition, and promotion of the apoptosis of HepG2 cells, as well as changes in levels of G1/S-specific cyclin-E1 (CCNE1) and activated caspase-3. Furthermore, the rho-associated protein kinase 1 (ROCK1) levels were opposite the levels of miR-145 expression in vivo and in vitro, and additional experiments with co-transfection of miR-145 mimics and pEGFP-N3-3'UTR provided the direct evidence that the ROCK1 gene is a target of miR-145. Moreover, a significant decrease or increase in the expression of ROCK1 was associated with nuclear factor-kB (NF-κB)(p65) activity, and lipopolysaccharide (LPS) significantly increased NF-κB(p65) activity, accompanied by recovery of the reduction in the number of HepG2 cells for miR-145 mimics. The NF-κB activity and cell number were significantly (p < 0.05, p < 0.01) increased in response to the overexpression of the ROCK1 gene in HepG2 cells.

CONCLUSIONS

We showed that miR-145 can target and downregulate ROCK1 expression, and it controls HCC by inhibiting the cell cycle and activating apoptosis via the ROCK1/NF-κB signaling pathway. Our findings will provide a new perspective for the therapy of HCC.

Melatonin inhibits the inflammation and apoptosis in rats with diabetic retinopathy via MAPK pathway

The article "Melatonin inhibits the inflammation and apoptosis in rats with diabetic retinopathy via MAPK pathway, by Y. Ma, Q. Zhao, Y. Shao, M.-Z. Cao, M. Zhao, D. Wang, published in Eur Rev Med Pharmacol Sci 2019; 23 (3 Suppl): 1-8-DOI: 10.26355/eurrev_201908_18620-PMID: 31389568" has been withdrawn from the authors. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/18620.

Long non-coding RNA PVT1 regulates glioma proliferation, invasion, and aerobic glycolysis via miR-140-5p

The article "Long non-coding RNA PVT1 regulates glioma proliferation, invasion, and aerobic glycolysis via miR-140-5p, by Y. Shao, H.-T. Chen, Q.-R. Ma, Y.-W. Zhang, Y.-Q. He, J. Liu published in Eur Rev Med Pharmacol Sci 2020; 24(1): 274-283-DOI: 10.26355/eurrev_202001_19922-PMID: 31957841" has been withdrawn from the authors. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/19922.

Quality improvement tool for rapid identification of risk factors for SARS-CoV-2 infection among healthcare workers

The rapid growth of the coronavirus disease 2019 (COVID-19) pandemic, limited availability of personal protective equipment, and uncertainties regarding transmission modes of severe acute respiratory syndrome coronavirus-2 have heightened concerns for the safety of healthcare workers (HCWs). Systematic studies of occupational risks for COVID-19 in the context of community risks are difficult and have only recently started to be reported. Ongoing quality improvement studies in various locales and within many affected healthcare institutions are needed. A template design for small-scale quality improvement surveys is proposed. Such surveys have the potential for rapid implementation and completion, are cost-effective, impose little administrative or workforce burden, can reveal occupational risks while taking community risks into account, and can be repeated easily with short time intervals between repetitions. This article describes a template design and proposes a survey instrument that is easily modifiable to fit the particular needs of various healthcare institutions in the hope of beginning a collaborative effort to refine the design and instrument. These methods, along with data management and analytic techniques, can be widely useful and shared globally. The authors' goal is to facilitate quality improvement surveys aimed at reducing the risk of occupational infection of HCWs during the COVID-19 pandemic.

Metformin inhibits proliferation and migration of endometrial cancer cells through regulating PI3K/AKT/MDM2 pathway

OBJECTIVE

To investigate the influences of metformin on the proliferation and migration of endometrial cancer (EC) Ishikawa cells and its mechanism.

MATERIALS AND METHODS

After the EC Ishikawa cells were treated with metformin at a concentration of 10 mM for 24 h, the proliferation of cancer cells was detected via XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-car-boxanilide] assay and colony formation assay, and the migration and invasion of cancer cells were detected via wound healing assay and transwell assay. In addition, the expressions of epithelial-mesenchymal transition (EMT)-related proteins, E-cadherin and Vimentin, were detected via Western blotting, and immunofluorescence staining was performed for E-cadherin in cancer cells. Finally, the protein expression level of phosphatidylinositol 3-hydroxy kinase/protein kinase B/murine double minute 2 (PI3K/AKT/MDM2) signaling pathway in cancer cells was detected via Western blotting.

RESULTS

Metformin inhibited the proliferation of Ishikawa cells in a concentration-dependent manner (0-10 mM) (p<0.05). Moreover, metformin (10 mM) also inhibited the proliferation of Ishikawa cells in a time-dependent manner (0-72 h) (p<0.05). The results of colony formation assay revealed that metformin (10 mM) could significantly inhibit the colony formation of Ishikawa cells (p<0.05). The results of wound healing assay and transwell assay showed that metformin (10 mM) significantly inhibited the migration and invasion of Ishikawa cells (p<0.05). According to further studies, metformin (10 mM) inhibited the EMT process in Ishikawa cells. Western blotting results manifested that the activation of PI3K/AKT/MDM2 signaling pathway was inhibited by metformin (p<0.05).

CONCLUSIONS

Metformin can inhibit the proliferation and migration of EC cells by inhibiting the activation of PI3K/AKT/MDM2 signaling pathway. Therefore, metformin is expected to be a new drug for the clinical treatment of EC.

Exploring of the Mechanism of Rib Fracture Caused by Landing on Different Parts of the Trunk after Falls from Height Using Finite Element Method

Abstract

Objective To study the mechanism of rib fracture caused by landing on different parts of the trunk using finite element method, and to provide some new techniques and new ideas for the reconstruction of the whole process of falls from height. Methods The finite element method was used to study the rib fracture of human security model THUMS4.0 caused by landing on different parts of the trunk. Then the model was compared with actual cases and the mechanism of rib fracture caused by falls from height was analyzed from a biomechanical point of view. Results There were some differences in the stress and strain distribution as well as the rib fracture sites when different parts touched the ground. Ribs on both sides of the body were fractured when the front of the trunk touched the ground, and the fractures were mainly located in the junction of the ribs and costal cartilage and the midaxillary line area. When the right anterior part of the trunk touched the ground, rib fracture occurred first on the side that touched the ground, and rib fractures were mainly located in the area from the right midaxillary line to the posterior axillary line, and junction of ribs on both sides and costal cartilage. When the back of the trunk touched the ground, the fracture sites were mainly located on the back of the ribs on both sides. When the right posterior part of the trunk touched the ground, multiple rib fractures were likely to occur in the parts that touched the ground. The plastic strains were mainly concentrated at the fracture sites, while the von Mises stresses were not only concentrated at the fracture sites, but also at other sites. Conclusion There are some differences in rib fracture location sites and injury mechanisms when different parts of the trunk touch the ground.

Role of echocardiography in screening for portopulmonary hypertension in liver transplant candidates: a meta-analysis

Objectives

To demonstrate the screening value of echocardiography for portopulmonary hypertension (POPH) in liver transplant candidates.

Design

Systematic review and meta-analysis.

Background

POPH is a complication of end-stage liver disease that adversely affects the outcome of orthotopic liver transplant. There are no specific symptoms in the early stage of POPH. POPH reduce the survival rate of patients with end-stage liver disease specially if they are not diagnosed. Therefore, early detection may improve prognosis. The objective of this study is to explore the screening value of echocardiography on liver transplant candidates for screening of POPH compared to right heart catheterization (RHC).

Method

PubMed, EMBASE and the Cochrane Library were searched by two independent reviewers for potentially eligible studies published up to 30 June 2019 to retrieve data based on per-patient analysis. STATA, Meta-DiSc, and RevMan were applied to perform this meta-analysis.

Results

Our search yielded 1576 studies, of which 11 satisfied the inclusion criteria. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR) and area under the summary receiver operating characteristic (SROC) curve (AUC) of echocardiography for POPH were 0.85 (95% CI [0.65–0.94]), 0.83 (95% CI [0.73–0.90]), 4.99 (95% CI [3.03–8.21]), 0.19 (95% CI [0.07–0.46]), and 0.91 (95% CI [0.88–0.93]), respectively. Deeks’ funnel plot did not indicate the existence of publication bias (P = 0.66).

Conclusions

Echocardiography, a noninvasive modality, provides superior screening for POPH, but the diagnosis of POPH still requires RHC. PROSPERO registration number CRD42019144589.

Government regulation and consumer evaluation after dairy products scandal in China

With the continuous expansion of the global dairy trade market, the quality and safety of the Chinese dairy market have a wide and far-reaching impact on the world. Based on the development of the dairy scandal in the past few years in China, this study illustrates the serious damage of melamine on human health and the negative impact on the dairy industry in China.

This study shows that the lack of effective government regulations is a key reason for dairy market failure. Consumers are lacking confidence in the quality of Chinese dairy products and the government's market regulations. The Chinese dairy market will continue to rely on imported dairy products. By analyzing the typical cases of the dairy market in China, this study aims to provide a guide for dairy industries in other countries.

Research Progress on Postmortem Changes of Computed Tomography Imaging Characteristics on Corpses

Abstract

Postmortem changes on corpses appear immediately after death, and can transform the original structure characteristics of the corpse to different degrees as well as show specific changes on computed tomography （CT） images, sometimes with false positives and false negatives, influencing the identification of injuries or diseases. This paper systematically summarizes the postmortem changes of computed tomography imaging characteristics on corpses, to further expand the application of virtopsy in the practices of forensic pathology identification, and provide reference for the identification of injuries, diseases and changes after normal death.

Piperine, a functional food alkaloid, exhibits inhibitory potential against TNBS-induced colitis via the inhibition of IκB-α/NF-κB and induces tight junction protein (claudin-1, occludin, and ZO-1) signaling pathway in experimental mice

BACKGROUND

Inflammatory bowel disease is a chronic immunoinflammatory disease of the gastrointestinal tract. Piperine, an alkaloid, has been reported to possess antioxidant, anti-inflammatory, antiapoptotic, and antiulcer potential.

AIM

To elucidate the plausible mechanisms of action of piperine on experimental trinitrobenzenesufonic acid (TNBS)-induced colitis by assessing various biochemical, molecular, histological, and ultrastructural modifications.

METHODS

Colitis was induced in male Sprague-Dawley rats via intrarectal instillation of TNBS. Then, the rats were treated with piperine (10, 20, and 40 mg/kg, p.o.) for 14 days.

RESULTS

TNBS induced significant (p < 0.05) colonic damage, which was assessed by disease activity index, macroscopic score, and stool consistency. The administration of piperine (20 and 40 mg/kg) significantly inhibited (p < 0.05) these damages. Treatments with piperine (20 and 40 mg/kg) notably inhibited (p < 0.05) the TNBS-induced elevation of oxido-nitrosative stress (superoxide dismutase, glutathione, malondialdehyde, and nitric oxide), 5-hydroxytryptamine, and hydroxyproline content in the colon. Furthermore, colonic inducible nitric oxide synthase (iNOs), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, IL-6, interferon-gamma, and cyclooxygenase-2 (COX-2) messenger RNA (mRNA) expressions were upregulated after TNBS instillation and piperine (20 and 40 mg/kg) significantly attenuated (p < 0.05) these elevated mRNA expressions. TNBS decreased the expressions of tight junction (TJ) protein (claudin-1, occludin, and zonula occludens-1 (ZO-1)) and increased the expressions of proapoptotic (caspase-1) protein. These expressions were markedly inhibited (p < 0.05) by piperine treatment. Histological and ultrastructural studies of transmission electron microscopy suggested that piperine significantly ameliorated (p < 0.05) TNBS-induced colonic aberrations.

CONCLUSION

Piperine ameliorated the progression of TNBS-induced colitis by modulating the nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor-alpha/nuclear factor-kappa B signaling pathway, thus inhibiting the overexpression of proinflammatory cytokines (TNF-α and IL's), COX-2, iNOs, oxido-nitrosative stress, and proapoptotic proteins (caspase-1) that may improve the expression of TJ protein (claudin-1, occludin, and ZO-1).

Dorsal-ventral patterned neural cyst from human pluripotent stem cells in a neurogenic niche

Despite its importance in central nervous system development, development of the human neural tube (NT) remains poorly understood, given the challenges of studying human embryos, and the developmental divergence between humans and animal models. We report a human NT development model, in which NT-like tissues, neuroepithelial (NE) cysts, are generated in a bioengineered neurogenic environment through self-organization of human pluripotent stem cells (hPSCs). NE cysts correspond to the neural plate in the dorsal ectoderm and have a default dorsal identity. Dorsal-ventral (DV) patterning of NE cysts is achieved using retinoic acid and/or sonic hedgehog and features sequential emergence of the ventral floor plate, P3, and pMN domains in discrete, adjacent regions and a dorsal territory progressively restricted to the opposite dorsal pole. This hPSC-based, DV patterned NE cyst system will be useful for understanding the self-organizing principles that guide NT patterning and for investigations of neural development and neural disease.

Quantitative Expression of RNA from Frozen Organs and Formaldehyde-fixed and Paraffin-embedded Tissues

Abstract

Objective Quantitative analysis and comparison of the expression of ribonucleic acid （RNA） from frozen organs and formaldehyde-fixed and paraffin-embedded （FFPE） tissues. Methods Frozen specimens of human brain, myocardium and liver tissues as well as FFPE samples at different postmortem intervals were collected and mass concentration of RNA was extracted and detected. Reverse transcription-quantitative polymerase chain reaction （RT-qPCR） technology was used to analyze the amplification efficiency and relative expression of each RNA marker. Results The mass concentration and integrity of RNA extracted from FFPE samples were relatively low compared with frozen specimens. The amplification efficiency of RNA markers was related with RNA species and the length of amplification products. Among them, glyceraldehyde-3-phosphate dehydrogenase （GAPDH） and β-actin （ACTB） with relatively long amplification products failed to achieve optimal amplification efficiency, whereas 5S ribosomal RNA （5S rRNA） achieved ideal amplification efficiency and showed quite stable expression across various tissues, therefore it was chosen as internal reference marker. The expression quantity of GAPDH and ACTB in frozen specimens with longer postmortem intervals and in FFPE samples with relatively long amplification products was decreased. The expressions of tissue-specific microRNAs （miRNAs）, GAPDH and ACTB with relatively short amplification products had consistency in the same tissues and FFPE samples. Conclusion Through standardizing the RT-qPCR experiment, selecting the appropriate RNA marker and designing primers of appropriate product length, RNA expression levels of FFPE samples can be accurately quantified.