Quantum dot fluorescent microsphere-based immunochromatographic strip for detecting PRRSV antibodies

Porcine reproductive and respiratory syndrome (PRRS) is an immunosuppressive disease caused by the porcine reproductive and respiratory syndrome virus (PRRSV). Current vaccine prevention and treatment approaches for PRRS are not adequate, and commercial vaccines do not provide sufficient cross-immune protection. Therefore, establishing a precise, sensitive, simple, and rapid serological diagnostic approach for detecting PRRSV antibodies is crucial. The present study used quantum dot fluorescent microspheres (QDFM) as tracers, covalently linked to the PRRSV N protein, to develop an immunochromatography strip (ICS) for detecting PRRSV antibodies. Monoclonal antibodies against PRRSV nucleocapsid (N) and membrane (M) proteins were both coated on nitrocellulose membranes as control (C) and test (T) lines, respectively. QDFM ICS identified PRRSV antibodies under 10 min with high sensitivity and specificity. The specificity assay revealed no cross-reactivity with the other tested viruses. The sensitivity assay revealed that the minimum detection limit was 1.2 ng/mL when the maximum dilution was 1:2,048, comparable to the sensitivity of enzyme-linked immunosorbent assay (ELISA) kits. Moreover, compared to PRRSV ELISA antibody detection kits, the sensitivity, specificity, and accuracy of QDFM ICS after analyzing 189 clinical samples were 96.7%, 97.9%, and 97.4%, respectively. Notably, the test strips can be stored for up to 6 months at 4 °C and up to 4 months at room temperature (18-25 °C). In conclusion, QDFM ICS offers the advantages of rapid detection time, high specificity and sensitivity, and affordability, indicating its potential for on-site PRRS screening. KEY POINTS: • QDFM ICS is a novel method for on-site and in-lab detection of PRRSV antibodies • Its sensitivity, specificity, and accuracy are on par with commercial ELISA kits • QDFM ICS rapidly identifies PRRSV, aiding the swine industry address the evolving virus.

[Clinical characteristics and surgical outcomes in pediatric progressive restrictive strabismus]

Objective: To investigate the clinical features, imaging manifestations, histopathological characteristics, and surgical outcomes in pediatric progressive restrictive strabismus. Methods: A retrospective case series study was conducted, including data from 9 cases (9 eyes) of pediatric progressive restrictive strabismus treated at Tianjin Eye Hospital from June 2017 to October 2022. The study compared the degree of globe protrusion in both eyes, changes in eyelid fissure height during internal and external rotation in the primary gaze, summarized clinical characteristics, and analyzed intraoperative conditions, surgical outcomes and postoperative histopathological results of strabismus correction surgery. Statistical analysis was performed using Wilcoxon signed-rank test and Friedman two-way analysis of variance. Results: All 9 cases involved unilateral onset, with 4 males and 5 females. Three cases affected the right eye, and six affected the left eye. Onset age ranged from 2 to 40 months. The degree of globe protrusion in the affected eyes was 13.00 (12.00, 13.00) mm for the right eye and 12.00 (12.00, 13.50) mm for the left eye, with no statistically significant difference (Z=-1.00, P=0.317). There were no significant changes in eyelid fissure height during internal rotation [8.00 (7.25, 8.00) mm], primary gaze [7.50 (7.00, 8.00) mm], and external rotation [8.00 (7.75, 8.00) mm] in the affected eyes (χ²=1.00, P=0.607). No apparent abnormalities were observed in head CT or MRI scans, serum, or immunological tests. However, orbital CT or MRI scans indicated thickening of different extraocular muscle bellies. Six out of nine cases underwent strabismus correction surgery, and postoperative examination revealed restriction in eye movement despite achieving orthophoria in the primary gaze. Tissue pathology of three cases showed increased collagen fiber proliferation in one, scattered bundles of smooth muscle fibers amid diffuse collagen fiber proliferation in another, and abnormal proliferation of striated muscle fibers with varying diameters, increased paired box (PAX)7-positive satellite cells expressing slow muscle myosin in the third case. Conclusions: Pediatric progressive restrictive strabismus presents with restrictive changes, without significant alterations in globe protrusion and eyelid fissure height. Imaging examinations reveal thickening of the extraocular muscle bellies in the affected eye. Although strabismus correction surgery improves eye position, postoperative eye movement remains restricted. Histopathological findings in some cases show abnormal proliferation of skeletal muscle fibers or collagen fibers.

[Significance of accurately interpreting the Bielschowsky tilt test in the differential diagnosis of superior oblique muscle paralysis]

Superior oblique muscle paralysis is a common type of vertical rotatory strabismus with various subtypes. Regardless of the subtype, the Bielschowsky tilt test plays a crucial role in the diagnosis of superior oblique muscle paralysis and is often considered a significant criterion for diagnosis and differential diagnosis. However, the sensitivity and specificity of the Bielschowsky tilt test for diagnosing superior oblique muscle paralysis are not 100% due to the mechanism involved. The test is not solely based on extraocular muscle imbalance but also involves reflex pathways of the vestibular system and central nervous system. Consequently, lesions affecting corresponding areas may yield positive results in the Bielschowsky tilt test. Additionally, vestibular and central nervous system lesions can also cause strabismus, leading to a lack of one-to-one correspondence between a positive Bielschowsky tilt test and superior oblique muscle paralysis. Therefore, correctly interpreting the role of the Bielschowsky tilt test in superior oblique muscle paralysis is of paramount importance for the effective clinical management and treatment of associated conditions.

[Recombinant porcine interferon-gamma expressed in CHO cells and its antiviral activity]

The aim of this study was to produce recombinant porcine interferon gamma (rPoIFN-γ) by Chinese hamster ovarian (CHO) cells expression system and to analyze its antiviral activity. Firstly, we constructed the recombinant eukaryotic expression plasmid pcDNA3.1-PoIFN-γ and transfected into suspension cultured CHO cells for secretory expression of rPoIFN-γ. The rPoIFN-γ was purified by affinity chromatography and identified with SDS-PAGE and Western blotting. Subsequently, the cytotoxicity of rPoIFN-γ was analyzed by CCK-8 test, and the antiviral activity of rPoIFN-γ was evaluated using standard procedures in VSV/PK-15 (virus/cell) test system. Finally the anti-Seneca virus A (SVA) of rPoIFN-γ activity and the induction of interferon-stimulated genes (ISGs) and cytokines were also analyzed. The results showed that rPoIFN-γ could successfully expressed in the supernatant of CHO cells. CCK-8 assays indicated that rPoIFN-γ did not show cytotoxicity on IBRS-2 cells. The biological activity of rPoIFN-γ was 5.59×107 U/mg in VSV/PK-15 system. Moreover, rPoIFN-γ could induced the expression of ISGs and cytokines, and significantly inhibited the replication of SVA. In conclusion, the high activity of rPoIFN-γ was successfully prepared by CHO cells expression system, which showed strong antiviral activity on SVA. This study may facilitate the investigation of rPoIFN-γ function and the development of novel genetically engineered antiviral drugs.

[Bovine viral diarrhea virus Erns protein expressed in Chinese hamster ovary cells and its immunogenicity analysis]

The aim of this study was to produce Erns protein of bovine viral diarrhea virus (BVDV) by using suspensively cultured CHO cells expression system and to analyze the immunogenicity of the purified Erns protein. In this study, the recombinant eukaryotic expression plasmid pcDNA3.1-BVDV-Erns was constructed based on the gene sequence of BVDV-1 NADL strain. The Erns protein was secreted and expressed in cells supernatant after transfecting the recombinant expression plasmid pcDNA3.1-BVDV-Erns into CHO cells. The expression and purification of the Erns protein was analyzed by SDS-PAGE, the reactivity was determined with anti-His monoclonal antibodies and BVDV positive serum with Western blotting. Immunogenicity analysis of the Erns protein was determined after immunizing New Zealand white rabbits, and the serum antibodies were tested by indirect ELISA (iELISA) and indirect immunofluorescence (IFA). The serum neutralizing titer of the immunized rabbits was determined by virus neutralization test. The concentration of the purified Erns protein was up to 0.886 mg/mL by BCA protein quantification kit. The results showed that the Erns protein could be detected with anti-His monoclonal antibodies and anti-BVDV sera. Serum antibodies could be detected by iELISA on the 7th day post-prime immunization, and the antibody level was maintained at a high titer until the 28th day post-immunization. The antibody titer was 1:128 000. Furthermore, the expression of the Erns protein in BVDV-infected MDBK cells could be detected with immunized rabbits sera by IFA. Moreover, antigen-specific neutralizing antibodies of 2.71 log10 was induced in rabbits. In this study, purified BVDV Erns protein was successfully produced using CHO suspension culture system, and the recombinant protein was proved to have a good immunogenicity, which may facilitate the development of BVD diagnosis method and novel subunit vaccine.

Assessing hydrological connectivity for natural-artificial catchment with a new framework integrating graph theory and network analysis

Anthropogenic activities alter the underlying surface conditions and arrangements of landscape features in a drainage basin, interfering with the pollutant (e.g., dissolved nitrogen, phosphorus) transport network configuration and altering the hydrological response. Assessing the impact of anthropogenic activities on hydrological connectivity for natural-artificial catchment is critical to understand the hydrological-driven ecosystem processes, services and biodiversity. However, quantifying this impact at catchment scale remains challenging. In this study, a new framework was proposed to quantify the impact of anthropogenic activities on hydrological connectivity combined with graph theory and network analysis. This framework was exemplified in a natural-artificial catchment of the Yangtze River basin of China. Based on remote sensing and field-investigated data, three transport networks were constructed, including natural transport network (N1), ditch-road transport network (N2), and terrace-dominated transport network (N3), which reflected the different human intervention. The results showed that human intervention improved the connectivity of the nodes and enhanced the complexity of the catchment transport network structure. Anthropogenic activities significantly decreased the hydrological structural connectivity of the catchment. In particular, compared with the N1 network, the critical nodes for hydrological connectivity which were judged by connectivity indexes were reduced by 92.94% and 95.29% in the N2 and N3 network, respectively. Furthermore, the ditch-road construction had a greater impact than terraces in decreasing hydrological structural connectivity at catchment scale. This framework has proven effective in quantifying the hydrological connectivity analysis under different human intervention at the catchment scale and facilitates the improvement of catchment management strategies.

Identification of Potential Novel B-Cell Epitopes of Capsid Protein VP2 in Senecavirus A

Senecavirus A (SVA) is a type of nonenveloped single-stranded, positive-sense RNA virus. The VP2 protein is a structural protein that plays an important role in inducing early and late immune responses of the host. However, its antigenic epitopes have not been fully elucidated. Therefore, defining the B epitopes of the VP2 protein is of great importance to revealing its antigenic characterization. In this study, we analyzed B-cell immunodominant epitopes (IDEs) of the VP2 protein from the SVA strain CH/FJ/2017 using the Pepscan approach and a bioinformatics-based computational prediction method. The following four novel IDEs of VP2 were identified: IDE1, 41TKSDPPSSSTDQPTTT56; IDE2, 145PDGKAKSLQELNEEQW160; IDE3, 161VEMSDDYRTGKNMPF175; and IDE4, 267PYFNGLRNRFTTGT280. Most of the IDEs were highly conserved among the different strains. To our knowledge, the VP2 protein is a major protective antigen of SVA that can induce neutralizing antibodies in animals. Here, we analyzed the immunogenicity and neutralization activity of four IDEs of VP2. Consequently, all four IDEs showed good immunogenicity that could elicit specific antibodies in guinea pigs. A neutralization test in vitro showed that the peptide-specific guinea pig antisera of IDE2 could neutralize SVA strain CH/FJ/2017, and IDE2 was identified as a novel potential neutralizing linear epitope. This is the first time VP2 IDEs have been identified by using the Pepscan method and a bioinformatics-based computational prediction method. These results will help elucidate the antigenic epitopes of VP2 and clarify the basis for immune responses against SVA. IMPORTANCE The clinical symptoms and lesions caused by SVA are indistinguishable from those of other vesicular diseases in pigs. SVA has been associated with recent outbreaks of vesicular disease and epidemic transient neonatal losses in several swine-producing countries. Due to the continuing spread of SVA and the lack of commercial vaccines, the development of improved control strategies is urgently needed. The VP2 protein is a crucial antigen on the capsids of SVA particles. Furthermore, the latest research showed that VP2 could be a promising candidate for the development of novel vaccines and diagnostic tools. Hence, a detailed exploration of epitopes in the VP2 protein is necessary. In this study, four novel B-cell IDEs were identified using two different antisera with two different methods. IDE2 was identified as a new neutralizing linear epitope. Our findings will help in the rational design of epitope vaccines and further understanding of the antigenic structure of VP2.

Deletion of MGF-110-9L gene from African swine fever virus weakens autophagic degradation of TBK1 as a mechanism for enhancing type I interferon production

African swine fever (ASF) caused by African swine fever virus (ASFV) is a devastating disease for the global pig industry and economic benefit. The limited knowledge on the pathogenesis and infection mechanisms of ASF restricts progress toward vaccine development and ASF control. Previously, we illustrated that deletion of the MGF-110-9L gene from highly virulent ASFV CN/GS/2018 strains (ASFV∆9L) results in attenuated virulence in swine, but the underlying mechanism remains unclear. In this study, we found that the difference in virulence between wild-type ASFV (wt-ASFV) and ASFV∆9L strains was mainly caused by the difference in TANK Binding Kinase 1 (TBK1) reduction. TBK1 reduction was further identified to be mediated by the autophagy pathway and this degradative process requires the up-regulation of a positive autophagy regulation molecule- Phosphatidylinositol-4-Phosphate 3-Kinase Catalytic Subunit Type 2 Beta (PIK3C2B). Moreover, TBK1 over-expression was confirmed to inhibit ASFV replication in vitro. In summary, these results indicate that wt-ASFV counteracts type I interferon (IFN) production by degrading TBK1, while ASFVΔ9L enhanced type I IFN production by weakening TBK1 reduction, clarifying the mechanism that ASFVΔ9L present the attenuated virulence in vitro.

[Characteristics of visual function in children with autism complicated with mental retardation]

Objective: To explore the characteristics of visual function and eye diseases in children with autism spectrum disorder (ASD) and mental retardation. Methods: It was a cross-sectional study. Two hundred and ninety-two cases (584 eyes) of children with ASD combined with mental retardation from 7 special education schools in Chaoyang District of Beijing, including 235 males (80.48%) and 57 females (19.52%); The age ranged from 2 to 18 years old. Subjective far and near vision, near stereoacuity, objective vision, diopter, anterior segment and fundus were examined. In addition, 300 students with normal intelligence level, aged 2 to 18 years, were included as controls. LogMAR was used to record vision examination. Subjective, objective vision and diopter were examined. Mann Whitney U test or Kruskal Wallis H test was used for the data of children with different genders, different age. Results: Among 584 eyes of children with ASD and mental retardation, 272 eyes (47.22%) were ametropia, 260 eyes (45.14%) were astigmatism, 29 eyes (5.03%) were hyperopia, 10 eyes (1.74%) were myopia, and 47 eyes (8.16%) were amblyopia risk factors. Among 292 children, there were 20 cases of strabismus (6.85%), 3 cases of color weakness (1.03%), and 4 cases of external eye abnormalities (1.37%). Two hundred and eleven children completed near stereopsis examination, of which 54 (25.59%) were within 100″ and 157 (74.41%) were within 200″ to 900″. Two hundred and seventy-two eyes with ametropia, 157 eyes (57.72%) needed correction but did not. The median and quartile of subjective and objective logMAR visual acuity were 0.22(0.10, 0.35), 0.10(0.00, 0.22), respectively; There were no significant differences in far visual acuity, near visual acuity, objective visual acuity, diopter, and near stereoacuity between different genders of ASD children with mild or moderate mental retardation (all P>0.05); There was a statistically significant difference in ASD children with mild mental retardation at different age rangs (H=21.453, P<0.001). There was a statistically significant difference in subjective tests such as far visual acuity and near visual acuity, for children with moderate mental retardation (Z=-3.508, -4.503; P<0.001). There was no statistically significant difference in objective visual acuity, diopter and near stereo acuity(all P>0.05). There are 300 healthy children as the control group, with LogMar's subjective far vision is 0.10(0.00, 0.22), and the objective vision is 0.00(0.00, 0.10), diopter 0.25 (-0.25, 0.50) D. Compared with healthy children, ASD children with mental retardation had a significant difference in subjective far vision and objective vision (Z=-8.527, -10.393; P<0.001). There was no significant difference in diopter (Z=-1.274, P=0.203). Conclusions: The subjective and objective visual acuity of children with ASD combined with mental retardation was lower than that of healthy children. The prevalence and uncorrected rate of refractive errors, strabismus, amblyopia and other eye diseases were significantly higher than those of healthy children. Their refractive errors were mainly astigmatism, and the rates of correction and treatment were low.

[Advances in the development of ocular cardiac reflex in extraocular muscle surgery]

Ocular cardiac reflex (OCR) usually occurs in ophthalmic surgery, especially in extraocular muscle(s) surgery. OCR generally can cause sinus bradycardia, arrhythmia, reduced atrial pressure, ventricular tachycardia, ventricular fibrillation, ventricular doublet, dizziness, nausea and other symptoms. Severe cases will appear cardiac arrest, respiratory arrest, etc. Recent studies on the mechanism of OCR and the relationship between surgical operation and anaesthesia in extraocular muscle surgery and the occurrence of OCR are reviewed in this paper in order to reduce the occurrence of OCR and treatment of OCR in extraocular muscle surgery.

Research progress on the proteins involved in African swine fever virus infection and replication

African swine fever (ASF) is an acute, hemorrhagic and highly contagious infectious disease caused by African swine fever virus (ASFV), which infects domestic pigs or wild boars. It is characterized by short course of disease, high fever and hemorrhagic lesions, with mortality of up to 100% from acute infection. Up to now, the lack of commercial vaccines and effective drugs has seriously threatened the healthy economic development of the global pig industry. ASFV is a double-stranded DNA virus and genome varies between about 170-194 kb, which encodes 150-200 viral proteins, including 68 structural proteins and more than 100 non-structural proteins. In recent years, although the research on structure and function of ASFV-encoded proteins has been deepened, the structure and infection process of ASFV are still not clear. This review summarizes the main process of ASFV infection, replication and functions of related viral proteins to provide scientific basis and theoretical basis for ASFV research and vaccine development.

[Graded vertical rectus tenotomy for small angle vertical deviation]

Objective: To observe the effectiveness of the graded vertical rectus tenotomy procedure for small-angle vertical deviation. Methods: Retrospective case series study. Twelve patients, including 8 males and 4 females, with an average age of (48±8) years were treated in Tianjin Eye Hospital from January 2017 to December 2019 for diplopia in primary gaze by strabismus surgery. The disease duration was (15±7) months. MRI/CT scan of the orbits and brain was performed to exclude the orbital and craniocerebral diseases. All patients underwent ocular movement examination, with the prism and alternate cover test to detect the deviation angle in primary gaze and the double Maddox test. Based on the results, the posterior segment of the nasal/temporal superior/inferior rectus muscle was operated. The changes of vertical and cyclotorsion deviation angle and the relationship between the vertical rectus graded tenotomy and corrected vertical deviation angle were observed at 1 day after surgery and the last follow-up. The vertical deviation angle was represented by M (Q₁, Q₃). Friedman test (Bonferroni correction) and linear fitting analysis were used for statistical analysis. Results: The follow-up time of all patients was (7±3) months. The vertical deviation angle in primary gaze before surgery [7.00 (5.25, 7.75) PD] was significantly different from that at 1 day after surgery [1.00 (1.00, 2.00) PD] and the last follow-up [1.50 (1.00, 2.00) PD] (P<0.001, P=0.003). There was no significant difference in postoperative cyclotorsion in all patients. Linear fitting results showed that 50% to 90% vertical rectus tenotomy corrected 5 to 8 PD vertical deviation (R²=0.72; P<0.001). Conclusion: The graded vertical rectus tenotomy procedure can effectively improve the small-angle vertical deviation in primary gaze.

Molecular Characterization and Gene Expression Analysis of Aquaporin in Haemaphysalis qinghaiensis

Aquaporins (AQPs) are important functional proteins and are widely present in the cell membrane of almost all organisms, mediating transmembrane transport of liquid and other solutes. Much is known about the molecular characterization of AQPs in other tick species; however, nothing is known about them in Haemaphysalis qinghaiensis. In this study, we first sequenced the transcript variants of AQPs in H. qinghaiensis (HqAQPs), analyzed the biological structure features of AQPs, and investigated the pattern of gene expression of the AQP gene of H. qinghaiensis in different tick tissues and stages to predict their biological functions. In conclusion, four AQP transcript variants (i.e., HqAQP1-1, HqAQP1-2, HqAQP1-3, and HqAQP1-4) of H. qinghaiensis were found, and the sequences were comparable with its orthologs from the reported tick species. Gene expression of AQPs in different tick tissues and stages showed the higher expression level in salivary glands and gut of adult female, as well as in the female and nymph than in Malpighian tubules, ovary, male, larvae, and egg. Further studies will be performed to evaluate the function of HqAQPs against H. qinghaiensis infestation on animals.

[Generation and immunogenicity evaluation of Senecavirus A virus-like particles]

To develop Senecavirus A (SVA) virus-like particles (VLPs), a recombinant prokaryotic expression plasmid pET28a-SVA-VP031 was constructed to co-express SVA structural proteins VP0, VP3 and VP1, according to the genomic sequence of the field isolate CH-FJ-2017 after the recombinant proteins were expressed in E .coli system, and purified by Ni+ ion chromatographic method. The SVA VLPs self-assemble with a high yield in vitro buffer. A typical VLPs with an average diameter of 25-30 nm which is similar to native virions by using TEM detection. Animals immunized by SVA VLPs shown that the VLPs induced high titers neutralizing antibodies in Guinea pigs. This study indicated that the VLPs produced with co-expressing SVA structural proteins VP0, VP3 and VP1 in prokaryotic system is a promising candidate and laid an important foundation for the development of a novel SVA VLPs vaccine.

[Clinical observation of anterior tucking of the superior oblique tendon for correction of excyclotropia in adults]

Objective: To investigate the clinical effect of anterior 1/3 superior oblique tendon tucking in acquired symptomatic excyclotropia adults. Methods: Retrospective case series. Seven patients (7 eyes) with acquired symptomatic excyclotropia who underwent an anterior 1/3 superior oblique tendon tuck procedure in Tianjin Eye Hospital from January 2019 to December 2019 were included. There were 5 male patients and 2 female patients, with an average age of (49±12) years old. All the patients had a history of a closed head injury. There was torsional diplopia in primary position, and eye movement examination showed paralysis of the superior oblique muscle in the affected eye, without obvious hyperactivity of the inferior oblique muscle. The anterior 1/3 tendon of the superior oblique muscle was tucked during surgery according to the relaxation of the superior oblique tendon in the forced duction test. The paired-sample nonparametric rank sum test was used to analyze the preoperative and postoperative (at 1 day after surgery and the last follow-up) excyclotropia angle. Results: The mean tuck amount was (7.7±1.8) mm (range, 6.0 to 10.0 mm). During operation, patients complained that excyclotropia improved markedly. The excyclotropia angle with the double Maddox rod test improved significantly from preoperative 10° (8°, 15°) to 2° (0°, 3°) at 1 day (Z=-2.379; P<0.05) and 2° (2°, 5°) at the last follow-up (Z=-2.375; P<0.05). The follow-up period was (112+38) days. All patients had no complaints of excyclotropia at the last follow-up. Conclusions: The anterior 1/3 superior oblique tendon tucking can effectively improve clinical symptoms in the primary position in adults with acquired excyclotropia and diplopia. The short-term postoperative results seem to be stable, without significant regression. (Chin J Ophthalmol, 2021, 57: 685-688).

[Clinical analysis and surgical treatment of atypical acute acquired concomitant esotropia]

Objective: To investigate the clinical characteristics, possible etiology and surgical efficacy of acute acquired concomitant esotropia (AACE) with atypical etiology. Methods: Case-control study. Twelve patients, including 7 males and 5 females, who complained of diplopia and were diagnosed with AACE in Tianjin Eye Hospital from January to December 2019 and underwent surgical treatment were included. The duration of the disease was (8.83±3.71) months. All patients underwent routine ocular examination except amblyopia and ocular organic lesions. MRI examination of the orbits and the brain was performed in all the patients in order to screen orbital and craniocerebral diseases, and patients denied that the existence of common causes of AACE (such as occlusion of one eye, mental or psychological factors, medium to high myopia, etc. during medical examination). The characteristics of the disease, the difference of deviation angle at 33 cm and 5 m, and the changes of deviation angle and stereopsis before and after surgery were analyzed. The forced duction test was performed before operation, and the distance between the sclera margin and the midpoint of the medial rectus muscle attachment was measured and compared with the patients with intermittent exotropia (10 cases) and comitant esotropia (10 cases). Paired sample t-test and one-way analysis of variance were used for statistical analysis. Results: The mean spherical equivalent was (1.70±0.88) D in all AACE patients, and the deviation angle was (22.42±5.82) prism diopter (PD) at 33 cm and (20.00±4.86) PD at 5 m in primary gaze, which were not statistically significant (P=0.371). The force duction test showed no obvious tension or contracture of the medial rectus and no paralysis. In patients with AACE, the horizontal distance from the midpoint of the medial rectus to the limbus was (5.20±0.27) mm, versus (5.30±0.25) mm in intermittent exotropia patients and (5.30±0.31) mm in concomitant esotropia patients. All the differences were not statistically significant (P=0.618). All the patients with AACE had residual esotropia (mean, 3.42 to 6.33 PD) at 6 weeks, 3 months, and 6 months postoperatively, and their stereopsis improved more than before, with no stereopsis in 2 patients before surgery and stereopsis in all 12 patients after surgery. Conclusions: AACE patients with atypical etiology do not have high myopia and hyperopia. There is no significant difference between the distance and near angles. The occurrence of esotropia is related to decompensation of esophoria, which may result in clinical symptoms of diplopia. Conventional surgery can reduce esotropia and restore stereoscopic vision, but there is still a small amount of esophoria after surgery. There is no abnormality in the attachment point of the medial rectus muscle. (Chin J Ophthalmol, 2021, 57: 348-352).

Amber codon is genetically unstable in generation of premature termination codon (PTC)-harbouring Foot-and-mouth disease virus (FMDV) via genetic code expansion

The foot-and-mouth disease virus (FMDV) is the causative agent of FMD, a highly infectious and devastating viral disease of domestic and wild cloven-hoofed animals. FMD affects livestock and animal products' national and international trade, causing severe economic losses and social consequences. Currently, inactivated vaccines play a vital role in FMD control, but they have several limitations. The genetic code expansion technology provides powerful strategies for generating premature termination codon (PTC)-harbouring virus as a live but replication-incompetent viral vaccine. However, this technology has not been explored for the design and development of new FMD vaccines. In this study, we first expanded the genetic code of the FMDV genome via a transgenic cell line containing an orthogonal translation machinery. We demonstrated that the transgenic cells stably integrated the orthogonal pyltRNA/pylRS pair into the genome and enabled efficient, homogeneous incorporation of unnatural amino acids into target proteins in mammalian cells. Next, we constructed 129 single-PTC FMDV mutants and four dual-PTC FMDV mutants after considering the tolerance, location, and potential functions of those mutated sites. Amber stop codons individually substituted the selected amino acid codons in four viral proteins (3D, L, VP1, and VP4) of FMDV. We successfully rescued PTC-FMDV mutants, but the amber codon unexpectedly showed a highly degree of mutation rate during PTC-FMDV packaging and replication. Our findings highlight that the genetic code expansion technology for the generation of PTC-FMD vaccines needs to be further improved and that the genetic stability of amber codons during the packaging and replication of FMDV is a concern.

[MRI study of rectus extraocular muscles in concomitant exotropia with small angle vertical deviation]

Objective: To observe the changes of four pulley locations of extraocular rectus muscles and rectus muscle volumes, as well as superior and inferior part ratio of horizontal rectus muscles, in concomitant exotropia with small-angle vertical deviation in primary gaze. Methods: Cross-sectional study. Data was collected from January 2018 to December 2019 in Tianjin Eye Hospital. The pulley position changes and volumes of four extraocular rectus muscles in the coronal position of patients who had concomitant exotropia without vertical deviation (group A) or with small-angle vertical deviation in primary gaze (<5 prism diopter; group B) and normal controls (group C) were observed using MRI, and the changes of the volume ratio of the superior and inferior parts of the horizontal rectus muscle were calculated. One way analysis of variance and Kruskal-Wallis test were used for statistical analysis. Results: There were 19 patients (38 eyes; 10 males, 9 females) aged (30±7) years in group A, ten patients (20 eyes; 4 males, 6 females) aged (27±6) years in group B, and 20 healthy volunteers (40 eyes) in group C. Age and gender distribution were matched among the three groups (all P>0.05). Among the three groups, the pulley locations of the four extraocular rectus muscles were not significantly different (all P>0.05). The medial rectus muscle volume in groups A [(358.6±44.9) mm³; t=6.405, P<0.01] and B [(334.7±35.6) mm³; t=6.025, P<0.01] was significantly smaller than group C [(437.5±49.3) mm³]. There was no statistically significant difference in the superior and inferior muscle volume ratio of the lateral rectus in three groups (all P>0.05), while the ratio in group B was more dispersive. Conclusions: The pulley location changes of four extraocular rectus muscles of patients with concomitant exotropia and small-angle vertical deviation in primary gaze are not significant, but the medial rectus volume in patients who had concomitant exotropia with vertical deviation or not is significantly smaller. The dispersive superior and inferior muscle volume ratio of the horizontal rectus muscles may be related to the small angle of vertical deviation in clinical examinations. (Chin J Ophthalmol, 2021, 57: 223-227).

Circ_0001982 accelerates the progression of colorectal cancer via sponging microRNA-144

OBJECTIVE

The aim of this study was to uncover the expression pattern and biological function of circ_0001982 in the progression of colorectal cancer (CRC).

PATIENTS AND METHODS

Relative expression level of circ_0001982 in 66 paired CRC tissues and adjacent normal tissues was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The association between circ_0001982 level and clinical indexes of CRC patients was assessed. The effect of circ_0001982 on cellular behaviors of HT29 and HCT-116 cells was evaluated in vitro. Dual-Luciferase reporter gene assay was conducted to verify the binding relation between circ_0001982 and microRNA-144. Finally, rescue experiments were performed to assess the role of the circ_0001982/microRNA-144 axis in mediating the progression of CRC.

RESULTS

Circ_0001982 was significantly up-regulated in CRC tissues when compared with adjacent normal ones. CRC patients with a high expression level of circ_0001982 showed a significantly higher rate of distant metastasis and worse survival. Knockdown of circ_0001982 remarkably attenuated the proliferative, migratory, and invasive capacities of HCT-116 cells. However, opposite results were observed after the overexpression of circ_0001982 in HT29 cells. MicroRNA-144 was verified as a target gene of circ_0001982, which could be negatively regulated by circ_0001982. Furthermore, microRNA-144 was capable of reversing the regulatory effect of circ_0001982 on the proliferative, migratory, and invasive capacities of CRC cells.

CONCLUSIONS

Up-regulated circ_0001982 was closely related to distant metastasis and poor prognosis of CRC. In addition, circ_0001982 attenuated the progression of CRC by negatively regulating microRNA-144.

The investigation of hepatitis A virus and hepatitis E virus co-infection in humans and animals in China

The aim of this study was to investigate the prevalence of co-infection of hepatitis A and hepatitis E virus (HAV/HEV) in patients with acute hepatitis as well as in different animal species. A total of 46 serum samples from patients diagnosed as hepatitis A or hepatitis E and 675 fecal samples of 11 animal species were collected. The IgM class antibodies to HEV and HAV, respectively, were detected by enzyme-linked immunosorbent assay. HEV and HAV RNAs were extracted from serum and fecal samples for the nested reverse transcription polymerase chain reaction. At least 10.9% (5/46) of the patients were co-infected with both HAV and HEV. Fifteen percent (18/120) of rabbit fecal samples and 17.5% (7/40) of swine fecal samples were positive for HEV RNA, but only 1% (2/200) of ferret fecal samples were positive for HAV RNA. Our study showed that co-infection with both HAV and HEV in patients and animals is infrequent. At least in our study, we showed that ferrets may represent the potential HAV hosts. Keywords: hepatitis A virus; hepatitis E virus; co-infection; zoonosis; prevalence.

Highly sensitive and specific detection of hepatitis B virus DNA and drug resistance mutations utilizing the PCR-based CRISPR-Cas13a system

OBJECTIVES

Undetectable or low-level hepatitis B virus (HBV) DNA and drug resistance mutations in patients may increase the risk of HBV transmission or cause active viral replication and other clinical problems. Here, we established a highly sensitive and practical method for HBV and drug resistance detection using a polymerase chain reaction (PCR) -based CRISPR-Cas13a detection system (referred to as PCR-CRISPR) and evaluated its detection capability using clinical samples.

METHODS

Specific CRISPR RNAs (crRNAs) are designed for HBV DNA detection and YMDD (tyrosine-methionine-aspartate-aspartate) variant identification. The HBV DNA was detected in 312 serum samples for HBV diagnosis using quantification PCR (qPCR) and PCR-CRISPR. Additionally, 424 serum samples for YMDD testing were detected by qPCR, direct sequencing, and our assay.

RESULTS

Using PCR-CRISPR, one copy per test of HBV DNA was detected with HBV-1 crRNA in 15 min after PCR amplification. Consistent results with qPCR were observed for 302 samples, while the remaining 10 samples with low-level HBV DNA were detectable by PCR-CRISPR and droplet digital PCR but not by qPCR. PCR-CRISPR diagnosed all 412 drug-resistant samples detected by the YMDD detection qPCR kit and direct sequencing, as well as the other 12 drug-resistant samples with low-level HBV DNA undetectable by qPCR and direct sequencing.

CONCLUSIONS

We developed a novel PCR-CRISPR method for highly sensitive and specific detection of HBV DNA and drug resistance mutations. One copy per test for HBV DNA and YMDD drug resistance mutations could be detected. This method has wide application prospects for the early detection of HBV infection, drug resistance monitoring and treatment guidance.

[Paying attention to the application of imaging examination in strabismus]

There are many pathogenic factors of strabismus. In addition to the changes of alignment and ocular movement, there may be abnormal pathways and development of extraocular muscles, abnormalities of orbital and intraorbital connective tissue, paralysis of cranial nerves (oculomotor nerve, trochlear nerve, and abductor nerve), and nuclear and supranuclear lesions, accompanied by other cerebral dysplasia sometimes. In recent years, advances in imaging technology and its application in the professional field of strabismus have made it possible to clearly observe the eye, orbital, intracranial, and innervation changes, which is helpful to clarify the etiology of strabismus and extraocular muscle-related diseases, and to provide a basis for the diagnosis and treatment of strabismus. Strabismus specialists should learn and pay attention to the application of imaging examination, so as to achieve in-depth understanding and accurate treatment. (Chin J Ophthalmol, 2020, 56: 166-170).

Experimental study on penetration characteristic of submerged steam jet in quiescent water

The direct contact condensation is an effective way to rapid depressurization for light water reactor, such as pressure suppression pool, for which the characteristic of steam plume is a key parameter to evaluate the efficiency of depressurization. In this paper, a series of visualization experiments are described which investigate the characteristic of steam plume, the influence of jetting direction, air mass fraction, water temperature, diameter of jet on the steam plume were analyzed. The results show that, the dimensionless steam plume length increased with the increase of inlet pressure and water temperature for pure steam submerged jet, a correlation was set up to predict the dimensionless penetration length and the predicted errors were within the band of ±15%. Furthermore, the penetration length decreased with the rise of air mass fraction due to buoyancy force, the penetration length increased with the increase of inlet pressure, and the jet penetration length for vertical jet is longer than horizontal jet about 25% at the same inlet pressure and air mass fraction.

[Smoking abstinence rate and its associated factors between abrupt and gradual smoking cessation]

Objective: To analyze and compare the abstinence rate of smoking quitting methods and its associated factors between abrupt and gradual smoking cessation in smokers with drug-based therapy. Methods: A prospective clinical study was conducted in patients undergoing quitting smoking intervention in Ruijin Hospital smoking cessation clinic between June 2013 and May 2016. All the subjects were randomized in a 1∶1 ratio into the abrupt smoking cessation group (smoking as usual over 3 weeks before a planned quit day, and then stopping smoking abruptly) and the gradual smoking cessation group (gradually reducing tobacco use over 3 weeks before a planned quit day, and then stopping smoking totally). The primary outcome was the complete abstinence rate, and the secondary outcomes included 1-month, 3-month and 6 month 7-day point prevalence of abstinence rates and 3 month sustained abstinence rates. Changes of body weight and drug adverse events were also compared. Results: A total of 314 moderate to severe nicotine-dependent patients were admitted in the study, including 157 patients in the abrupt smoking cessation and 157 patients in the gradual smoking cessation group. Fourteen patients fell off during the follow-up. For the complete abstinence rate, the gradual smoking cessation group was higher than the abrupt smoking cessation group(55.0% vs. 36.9%, χ(2)=9.841, P=0.002) .For 7-d smoking abstinence rate in the 1st, 3rd, 6th month, there was no significant difference between the 2 groups (all P>0.05). As for the 3-month sustained abstinence rate, a higher smoking quitting rate was seen in the gradual smoking cessation group compared to the abrupt smoking cessation group in the 6-month follow-up (17.9% vs.8.7%, χ(2)=5.441, P=0.020). The adverse drug reaction incidence was higher in the abrupt smoking cessation group than the gradual smoking cessation group (Gastrointestinal discomfort: 39.2% vs. 17.7%, χ(2)=12.336, P=0.000; Dreaminess: 40.2% vs. 13.3%, χ(2)=20.172, P=0.000). Conclusions: For moderate to severe nicotine-dependent patients, the gradual smoking cessation could serve to enhance the abstinence rate and mitigate the withdrawal symptoms.

[A study of superior oblique muscle changes in superior oblique palsy using magnetic resonance imaging]

Objective: To observe the magnetic resonance imaging(MRI) changes of superior oblique muscle and to study the relationship between changes and clinical signs in superior oblique muscle palsy. Methods: Cross-sectional study. Data was collected from January 2014 to January 2016 in Tianjin Eye Hospital. Twenty-three(30 eyes) patients who were diagnosed with superior oblique palsy included 15 patients with congenital superior oblique palsy [9 males and 6 females aged (32±13) years (range, 12-53 years)] and 8 cases with acquired superior oblique palsy [3 males and 5 females aged (36±15) years(range, 17-62 years)]. Twenty normal volunteers [11 males and 9 females aged (35±13) years (range, 15-60 years)] were also observed. Coronal MRI was used to detect superior oblique muscle morphological changes, as well as the maximum cross-sectional area and volume changes. The relationship between the morphological changes and vertical deviation and cyclotorsion in the primary gaze was analyzed. Rank sum test, t-test and Person correlation analysis were used for statistical analysis. Results: Two morphological changes were obtained using MRI in superior oblique muscle palsy, including round (19 eyes) and oval changes (11 eyes). The maximum cross-sectional area in eyes with the palsied superior oblique muscle [round, (10.38±1.76) mm(2); oval, (11.16±2.02) mm(2)] was significantly smaller than fellow eyes [(14.16±1.88) mm(2); Z=6.208, 5.178, both P<0.001] and eyes with normal superior oblique muscle [(15.40±1.71) mm(2); Z=8.215, 6.330, both P<0.001], and the volume changes [round, (104.92±13.36) mm(3); oval, (110.43±16.11) mm(3)] were also significantly different from fellow eyes [(254.57±20.15) mm(3); Z=7.511, 5.396, both P<0.001] and eyes with normal superior oblique muscle [(258.04±16.36) mm(3); Z=10.040, 6.936, both P<0.001]. There was no significant difference in vertical deviation between round and oval superior oblique muscle palsies (P>0.05). The cyclotorsion effect of the round change in superior oblique muscle palsy was significantly less than that of the oval change (5.47°±1.05° vs. 7.36°±0.97°, t=3.083, P=0.005). The correlation of the volume changes with vertical deviation angle in the primary gaze was not significantly different (round and oval, both P<0.05), but there was a correlation between the morphological changes and cyclotorsion strabismus (r=0.631, P=0.004; r=0.801, P=0.003). Conclusions: In the patients with superior oblique palsy, MRI scans shows that the maximum cross-sectional area decreased and the volume was smaller, which indicated superior oblique muscle atrophy. Deformation of superior oblique muscle do not significantly affect the vertical deviation, but is in correlation with cyclodeviation. (Chin J Ophthalmol, 2019, 55:20-24).

[Advances in research of synergistic divergence]

Synergistic divergence is a rare condition characterized by complete absence of adduction that is associated with simultaneous abduction of the affected eye on attempted adduction. This causes the affected eye to move further into abduction on gaze to the normal side and results in extreme divergence of both eyes. It is sometimes referred to as exotropic Duane syndrome with synergistic divergence (type 4 Duane syndrome) or congenital fibrosis syndrome with synergistic divergence. Diseases combined with synergistic divergence fall within the category of congenital cranial dysinnervation disorders (CCDDs). The ocular associations reported with synergistic divergence are uncommon and include Horner syndrome, ocular albinism, foveal hypoplasia, Goldenhar syndrome and pupillary abnormalities. MRI and electro-oculographic study suggested that this is the result of CCDDs. Various surgical techniques have been tried in individual cases including large recession of the lateral rectus muscle, lateral rectus muscle extirpation, large resection of the medial rectus (MR) muscle, weakening procedures of the oblique muscles, combination of lateral rectus orbital wall fixation with MR resection, but further investigations with large-scale samples are needed. Recent research advances in the definition, etiology, and treatment of synergistic divergence are reviewed in this article. (Chin J Ophthalmol, 2019, 55:63-67).

[The preliminary study of stimulus input temporal changes on the visual cortex of rats at different ages]

Objective: To observe the impact of the input temporal changes on visual cortex of rats cells and the change of the synaptic efficacy, for the study of visual developmental plasticity mechanism. Methods: Experimental research. The brain slice of ten 14d healthy Wistar rats and ten 21d healthy Wistar rats were recorded with whole cell recording technique, using single stimulation and combined stimulate model, to observe the visual cortex of rats neurons changes in synaptic activity. Change the stimulus input sequence, and observe the visual cortex of rats changes of synaptic efficacy. Using the paired t test to compare the change of excitatory postsynaptic potential (EPSC) of visual cortex. Result: The difference between single stimulation and combined stimulate about EPSC was statistically significant, which was decreased (14.3±7.4) % (n=15) in single stimulation and (53.4±17.5) % (n=20) in combined stimulation for P14 rats which were long-term depression (t_s2=3.9, t_s1+s2=2.2; P<0.05) , and was increased (27.5±11.4) % (n=16) in single stimulation and (34.6±10.3) % (n=10) in combined stimulation for P20 rats which were long-term potentiation (t_s2=2.3, t_s1+s2=3.5; P<0.05) . Rats in different development period have a specific time window for input temporal changes. Combined stimulation patterns produced by the neuron cell reaction were not just an accumulation of simple response caused by single stimulation. For P14 rats, its time window was of about ±0.5ms. However, for P20 rats, scope of time window reduced to ±0.1ms. Conclusions: Different development period of rats, change the stimulation pattern can cause the change of the visual cortex synapses reaction, and stimulate the temporal change within a specific time window to producenonlinear results. (Chin J Ophthalmol, 2016, 52: 936-940).

PHACTR4 regulates proliferation, migration and invasion of human hepatocellular carcinoma by inhibiting IL-6/Stat3 pathway

OBJECTIVE

Phosphatase and actin regulator 4 (PHACTR4) is one member of the largely uncharacterized PHACTR family of protein phosphatase 1 (PP1)-and actin-binding proteins. PHACTR4 is significantly deleted or mutant in many tumor subtypes, such as breast, colorectal, lung, neural, ovarian, and renal cancers. However, the role of PHACTR4 in human hepatocellular carcinoma (HCC) is completely unknown.

MATERIALS AND METHODS

Ten paired HCC tissues and adjacent non-cancerous tissues were used to detect the expression PHACTR4. Real-time PCR was used to detect the mRNA level of PHACTR4 in clinic samples. The protein level of PHACTR4 was determined by Western blot. Retrovirus-based gene transduction was used to generate Flag-tagged PHACTR4 HepG2 stable cell line. BrdU assay was used to determine the cell growth of HepG2 cells. The cell cycle distribution was detected by flow cytometry assay. In vitro scratch wounding and Matrigel invasion assays were used to test the migration and invasion ability of HepG2 cells.

RESULTS

The expression of PHACTR4 was noticeably decreased in clinical HCC tissues, compared to the non-tumoral tissues. Overexpression of PHACTR4 inhibited HCC cells proliferation, colony formation, migration and invasion, and resulted in significant cycle arrest. PHACTR4 attenuated both constitutive and IL-6-induced phosphorylation of signal transducer and activator of transcription 3 (Stat3), and inhibited Stat3 downstream genes expression.

CONCLUSIONS

Overall, our results suggest that PHACTR4 is a tumor suppressor in HCC by inhibiting IL-6/ Stat3 pathway.

Stabilization of boron carbide via silicon doping

Boron carbide is one of the lightest and hardest ceramics, but its applications are limited by its poor stability against a partial phase separation into separate boron and carbon. Phase separation is observed under high non-hydrostatic stress (both static and dynamic), resulting in amorphization. The phase separation is thought to occur in just one of the many naturally occurring polytypes in the material, and this raises the possibility of doping the boron carbide to eliminate this polytype. In this work, we have synthesized boron carbide doped with silicon. We have conducted a series of characterizations (transmission electron microscopy, scanning electron microscopy, Raman spectroscopy and x-ray diffraction) on pure and silicon-doped boron carbide following static compression to 50 GPa non-hydrostatic pressure. We find that the level of amorphization under static non-hydrostatic pressure is drastically reduced by the silicon doping.

Diagnostic performance of FDG PET or PET/CT in prosthetic infection after arthroplasty: a meta-analysis

AIM

The purpose of this study was to systematically review and perform a meta-analysis of published data regarding the diagnostic performance of positron emission tomography (PET) or PET/computed tomography (PET/CT) in prosthetic infection after arthroplasty.

METHODS

A comprehensive computer literature search of studies published through May 31, 2012 regarding PET or PET/CT in patients suspicious of prosthetic infection was performed in PubMed/MEDLINE, Embase and Scopus databases. Pooled sensitivity and specificity of PET or PET/CT in patients suspicious of prosthetic infection on a per prosthesis-based analysis were calculated. The area under the receiver-operating characteristic (ROC) curve was calculated to measure the accuracy of PET or PET/CT in patients with suspicious of prosthetic infection.

RESULTS

Fourteen studies comprising 838 prosthesis with suspicious of prosthetic infection after arthroplasty were included in this meta-analysis. The pooled sensitivity of PET or PET/CT in detecting prosthetic infection was 86% (95% confidence interval [CI] 82-90%) on a per prosthesis-based analysis. The pooled specificity of PET or PET/CT in detecting prosthetic infection was 86% (95% CI 83-89%) on a per prosthesis-based analysis. The area under the ROC curve was 0.93 on a per prosthesis-based analysis.

CONCLUSION

In patients suspicious of prosthetic infection, FDG PET or PET/CT demonstrated high sensitivity and specificity. FDG PET or PET/CT are accurate methods in this setting. Nevertheless, possible sources of false positive results and influcing factors should kept in mind.

Hypothyroidism and first-trimester spontaneous miscarriages

OBJECTIVE

To evaluate the association between hypothyroidism and first-trimester spontaneous miscarriages and to explain the mechanism.

MATERIALS AND METHODS

Patients admitted between October and May 2011 with threatened miscarriage in the first trimester were analyzed and levels of progesterone and thyroid hormones as T3, T4, and thyroid-stimulating hormone (TSH) were estimated. Once hypothyroidism was diagnosed, patients were treated with sodium levothyroxine (LT4) as substitution and outcomes were observed.

RESULTS

Measurement of progesterone was useful for predicting the outcome of threatened miscarriage The results showed that progesterone (P) = 14.74 ng/ml is selected as predictive value to judge whether the fetal treatment was successfully or not. When serum P value is above 14.74 ng/ml before treatment, it may favour a miscarriage, if the serum P value is below 14.74 ng/ml, miscarriage is unlikely; its sensitivity and specificity are high. The risk for miscarriage in patients diagnosed with hypothyroidism in which LT4 substitution was similar to the level observed in the controls, and P between the two groups had no distinct difference. The mechanism explaining the risk of miscarriage increased by thyroid disorders remains unclear, which needs advanced research.

CONCLUSION

Screening of thyroid disorders has important clinical significance in early pregnancy, and substitution of LT4 to those who are in the early pregnancy with hypothyroidism could reduce the risk of miscarriage.

Optimization of electrotransfection conditions of mammalian cells with different biological features

We introduced eukaryotic expression plasmid pEGFP-N1 encoding green fluorescent protein (GFP) genes into cells with different biological features through electroporation. The effects of conditions, including voltage, capacitor flow, pulse cycle, DNA dosage and buffer, on transfection efficiency were investigated based on fluorescent microscopy and posttransfection survival rate of cells by staining with trypan blue. Better electrotransfection outcomes were achieved in the following epithelial cells: Vero cells at 300 V/850 μF, PK15 cells at 300 V/500 μF, MDCK cells at 200 V/600 μF, F81 cells at 200 V/500 μF, cancer cells MB49 at 300 V/400 μF, Hela cells at 200 V/450 μF, HF-29 cells at 300 V/800 μF and B16F1 cells at 200 V/650 μF. Among fibroblast cells, better electrotransfection was achieved in BHK21 cells at 300 V/600 μF and ST cells at 200 V/750 μF. RPMI-1640 medium without antibiotics and serum demonstrated higher electrotransfection efficiency and cell survival rate than other cell culture media as electroporation buffer. Our findings further prove that electroporation transfection is an effective method for genetic transfection. Cells with different biological features require varying transfection conditions to obtain higher transfection efficiency of target genes.

Upconversion nanoparticles modified with aminosilanes as carriers of DNA vaccine for foot-and-mouth disease

The potential of the upconversion nanoparticles NaYF(4):Yb/Er@silica(UCPs)/plasmid DNA (pcDNA3.1/VP1-GFP) complex in inducing immune responses was evaluated using the UCPs as carriers of the foot-and-mouth disease virus (FMDV AsiaI/Jiangsu2005) DNA vaccine. The UCPs protection against DNaseI degradation was measured using an in vitro inhibition assay. The expression of the plasmid in vivo was determined via confocal microscopy. Its biocompatibility was evaluated through cytotoxicity assay. Based on the results, the aminosilane-modified UCPs can electrostatically bind, condense, and protect plasmid DNA. Cell viability assays demonstrated that the cytotoxicity of the UCPs/plasmid DNA complex is lower than that of the cationic lipid/plasmid DNA complex, and that the transfection efficiency of UCPs is the same as that of the cationic lipid. Furthermore, the UCP/plasmid DNA complex was intramuscularly administered to guinea pigs. Humoral and cellular immune responses were detected using indirect enzyme-linked immunosorbent assay (ELISA), micro-neutralization assay, and T-lymphocyte proliferation assay. Anti-FMDV specific antibodies, neutralizing antibodies, and T-lymphocyte proliferation responses were induced after vaccination. In the challenge test, all the guinea pigs vaccinated with the UCPs/plasmid DNA complex were fully protected from the FMDV challenge. The current study encourages the use of UCPs as an effective nanosystem for gene delivery to cells for in vitro and in vivo vaccination, and other therapeutic applications.

P1-02-04: Estrogen Receptor beta Inhibits Breast Cancer EMT by Regulating the Expression of miR-200

Estrogen receptor beta (ERβ) mediates the effects of estrogens in a variety of human tissues and regulates cellular processes involved in initiation and progression of breast cancer such as cell proliferation and migration. Clinical studies produced contradictory data regarding the role for ERβ in prognosis of metastatic breast cancer and the molecular mechanism through which ERβ influences cell migration and invasion has not been fully elucidated. Here we show that induction of ERβ expression inhibits epithelial to mesenchymal transition (EMT) in metastatic breast cancer cells. This correlates with an ERβ-mediated induction in the expression of the epithelial marker E-cadherin and downregulation of its transcriptional repressors ZEB1 and SIP1. ERβ alters the expression of ZEB1 and SIP1 by inducing the expression of the miR-200a, miR200b and miR-429. Downregulation of these miRNAs in ERβ-expressing cells resulted in decreased cell-cell contact and decline of E-cadherin levels. In addition, ERβ was found to inhibit the invasiveness of metastatic breast cancer cells in a zebrafish xenotransplantation model. We are now examining breast cancer specimens derived from ductal carcinomas and metaplastic breast cancers to see whether ERβ levels decline in the mesenchymal regions and ERβ expression is correlated with epithelial markers. These data propose a crucial role for ERβ in the regulation of EMT and in prognosis of invasive and metastatic breast cancer.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-02-04.

57 NUCLEAR TRANSFER WITH RABBIT EMBRYONIC STEM CELLS: SERUM-STARVATION IMPROVES THE QUALITY OF CLONED EMBRYOS

Rabbit cloning by NT with somatic cells is so far a rather inefficient process. However, this technology is urgently required to generate rabbits with a humanized immune system as a source of human polyclonal antibodies. Embryonic stem cells (ESCs) have a number of advantages over somatic cells as tools for cell-mediated transgenesis including long periods of proliferation in vitro, higher frequency of homologous recombination between exogenous and chromosomal DNA, and less requirements for reprogramming (Rideout et al. 2000 Nat. Genet. 24, 109–110). To improve rabbit cloning we have derived and characterized 19 putative rabbit ESC lines and tested cells from 6 lines as donors for NT. First, we assessed in vitro development of NT embryos. Blastocyst rates varied in the range of 6–68% depending on the particular cell line and passage number, but the quality of the resultant embryos was worse compared to NT embryos derived from adult fibroblasts [hatched blastocysts: 13/214 (6%) v. 36/86 (42%), respectively]. Transfer of NT embryos derived from the ESC line showing the highest development to blastocysts into recipients resulted only in implantations (70%, 7/10) but not in offspring. Assuming that poor quality of NT embryos derived from ESCs could be due to the incompatibility between cell cycles of donor and recipient cells we used serum starvation to make ESCs more suitable for nuclear transfer. Serum starvation of one of the ESC lines (0.5% FCS for 3 days) greatly improved the quality of cloned embryos compared to those derived from non-starved cells of the same ESC line as indicated by the high proportions of hatched [38/151 (25%) v. 4/153 (3%)] and attached [25/151 (17%) v. 0%] to the surface of a culture dish blastocysts. Moreover, some of these blastocysts grew in vitro for 14–25 days. Our study provides evidence that the quality of NT embryos derived from ESCs can be significantly improved using serum starvation of donor cells suggesting possible effect of this treatment on the cell cycle synchronization. We are currently testing whether serum starvation of ESCs would also improve post-implantation development of rabbit NT embryos. This work is supported by Roche Diagnostic GmbH.

Design of annular photonic crystal slabs

We present the design of realistic annular photonic-crystal (APC) structures of finite thickness aiming to obtain a complete photonic bandgap (PBG). The APC is composed of dielectric rods and circular air holes in a triangular lattice such that each rod is centered within each hole. The optical and geometrical values of the structure are studied, and the interplay between various design parameters is highlighted. The coupled role of the inner-dielectric-rod radius, material types, and slab thickness is investigated. It is shown that the slab thickness is vital to obtain a complete photonic bandgap below the light line, and the specific value of the inner-dielectric-rod radius to sustain the maximum PBG if the hole radius is fixed at proper value is found.

102 RABBIT CLONING: HISTONE ACETYLATION STATUS OF DONOR CELLS AND CLONED EMBRYOS

Epigenetic status of the genome of a donor nucleus is likely to be associated with the developmental potential of cloned embryos produced by somatic cell nuclear transfer (SCNT). Prevention of epigenetic errors by manipulation of the epigenetic status of donor cells is expected to result in improvement of cloning efficiency. In this study, we transferred cultured rabbit cumulus cells (RCC) and fetal fibroblasts (RFF) from genetically marked rabbits (Ali/Bas) into metaphase II (MII) oocytes and analyzed the levels of histone H3K9 acetylation in donor cells and cloned embryos. We also assessed the correlation between the histone acetylation status of donor cells and cloned embryos and their developmental potential. To test whether alteration of the histone acetylation status affects development of cloned embryos, we treated donor cells with sodium butyrate (NaBu), a histone deacetylase inhibitor. Further, we tried to improve cloning efficiency by chimeric complementation of cloned embryos with one or two blastomeres from in vitro-fertilized or parthenogenetic embryos. Histone acetylation in donor cells and cloned embryos was detected by anti-acH3K9 antibody using Western immunoblot analysis or immunochemistry, respectively. Data were analyzed by chi-square (developmental rates) or Student-Newman-Keuls (histone acetylation) test. The levels of acetylated histone H3K9 were higher in RCCs than in RFFs (P &lt; 0.05). Although the type of donor cells did not affect development to blastocyst, after transfer into recipients, RCC-cloned embryos induced a higher initial pregnancy rate as compared to RFF-cloned embryos (40% vs. 20%; P &lt; 0.05). However, almost all pregnancies with either type of cloned embryos were lost by the middle of gestation and only one fully developed; a live RCC-derived rabbit was obtained. Treatment of RFFs with NaBu significantly (P &lt; 0.05) increased the level of histone H3K9/14 acetylation and the proportion of nuclear transfer embryos developing to blastocyst (49% vs. 33% with non-treated RFF; P &lt; 0.05). The distribution of signals for acH3K9 in either group of cloned embryos did not resemble that in in vivo-fertilized embryos, suggesting that reprogramming of this epigenetic mark is aberrant in cloned rabbit embryos and cannot be corrected by treatment of donor cells with NaBu. Aggregation of embryos cloned from NaBu-treated RFFs with blastomeres from in vivo-derived embryos improved development to blastocyst, but no cloned offspring were obtained. Two live cloned rabbits were produced from this donor cell type only after aggregation of cloned embryos with a parthenogenetic blastomere. Our study demonstrates that the levels of histone acetylation in donor cells and cloned embryos correlate with their developmental potential and can be a useful epigenetic mark to predict efficiency of SCNT rabbits. This work was supported by the Bayerische Forschungsstiftung and by Therapeutic Human Polyclonals, Inc.