Objective To study the effects of fluoride on longitudinal growth and pathological changes of cultured rat metatarsal bone rudiments.Methods Twenty-four neonatal SD rats were divided into four groups according to the random number table,then the second,third and fourth metatarsal bone rudiments were surgically isolated.The left metatarsal bone rudiments were cultured in α-MEM without F-as control group and the right metatarsal bone rudiments from the same rat were cultured in α-MEM with 1 × 10-7,1 × 10-6,1 × 10-5 and 1 × 10-4 mol/L F-.The length and width of the mineralized area of metatarsal were measured on day 0,day 1,day 4 and day 7,respectively,and the pathological changes of metatarsal bone rudiments were observed by the routinely paraffin-embedded sections method on day 7.Results On day 7,the length of the mineralized area was significantly lower of right metatarsal bone [(240.5 ± 139.3)μm] than the left metatarsal bone [(394.1 ± 173.9)μm,t =4.37,P ＜ 0.01] in the 1 × 10-4 mol/L F-group,but the width of the mineralized area [(239.9 ± 119.4)μm] was not different significantly compared to the left metatarsal bone [(223.3 ± 99.9)μm,t =0.44,P ＞ 0.05].The relative vertical growth rate of the mineralized area on day 4 was significantly lower of right metatarsal bone [(2.43 ± 1.44)％] than left metatarsal bone [(8.34 ± 1.74)％,t =3.21,P ＜ 0.01] in 1 × 10-4 mol/L F-group,and the difference was also significant on day 7 [(16.16 ± 2.87)％ vs.(26.52 ± 4.46)％,t =3.13,P ＜ 0.01].Toluidine blue staining results showed that the thickness of cartilage cells of proliferation and hypertrophic layers was significantly lower of right metatarsal bone [(111.33 ± 27.29),(125.33 ± 30.08)μm] than left metatarsal bone [(127.33 ± 38.36),(160.50 ± 42.73)μm,t =4.82,5.81,all P ＜ 0.01] in 1 × 104 mol/L F-group.The ratio of proliferative and hypertrophic layers was significantly higher of right metatarsal bone (0.93 ± 0.36) than left metatarsal bone (0.83 ± 0.32,t =4.42,P ＜ 0.01) in 1 × 10-4 mol/L F-group.Conclusions Our findings indicate that excessive fluoride could cause longitudinal bone growth inhibition.Such growth inhibition is mediated by decreased chondrocyte proliferation and differentiation and the disproportion of proliferation and differentiation.

Objective To investigate the application of small dose of ketamine during induction of anesthesia in patients after coronary artery bypass grafting neutrophil superoxide generation effect .Methods 30 patients undergoing elective coronary artery bypass grafting operation were randomly divided into 2 groups ,in the fentanyl induced respectively based on combined with small dose of ketamine (ketamine group) or normal saline (control group) ,a blood sample collection time points :before ,immediately after extracorporeal circulation operation ,operation after 1-6 days .Neutrophil function by using (12-) fourteen acid and phorbol ester (-13-) acetate (PMA) ,yeast polysaccharide or formyl-methylthio-light-phenylalanine after stimulation of superoxide production de-termination method .Results During general anesthesia combined with low dose ketamine inhibits superoxide anion increases .In ad-dition ,ketamine reduces perioperative 2 -6 days of the neutrophil percentage .Conclusion Ketamine can reduce the activation of neutrophils after cardiopulmonary bypass .

Objective To investigate the effect of nano-?-linolenic acid on the expression of cathepsin B(CB) in mice with viral myocarditis(VM).Methods Eighty male Balb/c mice were randomly divided into 4 groups:control group,myocarditis group,low-dose intervention group and high-dose intervention group,each group had 20 mice.Mice in control group were inoculated introperitoneally with eagle′s solution,every mouse in the last 3 groups was treated with 0.1 mL Coxsackie B3 virus(CVB3) intraperitoneally.Then,mice in low-dose intervention group and high-dose intervention group were treated with 60 mg?kg-1and 180 mg?kg-1 nano-?-linolenic acid solution for 7 days,respectively.Mice in control group and myocarditis group were treated with 9 g?L-1 saline for 7 days.All mice were killed on the 15th day,and the specimens of hearts and serum were conserved.Myocardial histopathology was determined with hematoxylin and eosin stain.The expression levels of myocardial CB mRNA were detected by reverse transcription polymerase chain reaction.Serum CB concentration was examined by enzyme-linked immunosorbent assay.Results The mortality rate was 0,45%,30% and 20% in control group,myocarditis group,low-dose intervention group and high-dose intervention group,respectively;the mortality rate was significantly lower in high-dose intervention group compared with myocarditis group(P0.05).The expression level of CB mRNA and serum CB concentration were markedly higher in myocarditis group than those in control group(Pa

Objective To investigate correlation between Helicobacter pylori infection and incidence of myocardial infarction and cerebral infarction ,and serum homocysteine(Hcy) level .Methods A total of 72 patients with myocardial infarction ,86 patients with cerebral infarction and 80 healthy subjects were enrolled and detected for Hp‐IgG and serum Hcy by using enzyme‐linked im‐munosorbent assays and enzymatic cycling method .Relationship between Hp infection and serum level of Hcy were analyzed .Results The positive rate of Hp‐IgG and serum Hcy level in patients with myocardial infarction were significantly higher than healthy subjects(P<0 .05) .Among patients with myocardial infarction ,serum level of Hcy in Hp‐IgG positive patients was higher than that in Hp‐IgG negative patients(P<0 .05) .The positive rate of Hp‐IgG between patients with cerebral infarction and healthy subjects was without significant difference(P>0 .05) .Among patients with cerebral infarction ,serum level of Hcy between Hp‐IgG positive patients and Hp‐IgG negative patients were without significant difference(P>0 .05) .But serum Hcy level in patients with cerebral infarction was significantly higher than that in healthy subjects(P<0 .05) .Conclusion Hp infection might promote the occurrence of myocardial infarction by affecting serum level of Hcy .However ,there might be without obvious correlation between Hp infection and the occurrence of cerebral infarction .And there could be no direct association between high serum level of Hcy in patients with cerebral infarction and Hp infection .

Objective To investigate how mobility training affects the synapses and their functioning in the region around a cerebral infarct.Methods One hundred and fifty rats were randomly divided into 5 groups:a mo- tor training group,a normal saline group,an Ara-c inhibition group,a mevastatin group and a control group.Cere- bral infarcts were surgically induced in all 150 rats,and the level of either glial fibrillary acidic protein(GFAP)or synaptophysin,and the cholesterol content around the infarct were observed at 7,21 and 42 days using immunohisto- chemical staining and high performance liquid chromatography.Results At 7,21 and 42 days after the infarct model was induced,significant differences in the optical density of either GFAP or synaptophysin and in cholesterol levels were noted between the motor training group and the control group.Ara-c inhibition was also significantly high- er in the controls.The optical density of synaptophysin and the cholesterol levels were significantly lower in the me- vastatin group than in the motor training group.Conclusion Motor skill training can improve synapse redefinition in rats with a model of acute cerebral infarct.Astrocytes may play a crucial role by means of the secretion of choles- terol in the region around the infarct.

Optical coherence tomography (OCT),as a noncontact,innovative technology,can produce high-resolution images of ocular tissues.This technology is originally used for posterior segment in ophthalmology,which were widely utilized for the anterior segment at first.The development of anterior segment OCT (AS-OCT) technology enables the precise visualization of anterior segment structure.Moreover,ultrahigh-resolution OCT (UHR-OCT) has been helpful for diagnosis and management of corneal and anterior segment diseases,including quantification of tear film for dry eye,authentication of ocular surface squamous neoplasia (OSSN),pterygium,keratoconus,traumatic corneal injuries,etc.Besides,UHR-OCT can be also used for planning and performing surgery for anterior segment,such as corneal transplantation,and monitoring of epithelial wound healing and postoperative course as well.Moreover,this technology can help understand the physiology and pathophysiology of the anterior segment structure.Therefore,this review will give a review on the application of UHR-OCT for diagnosis and management of corneal and anterior segment disorders.

AIM: To evaluate the effects induced by topical antiglaucomatous drugs, Travoprost eyedrops on tear film.
METHODS: Eighteen patients ( 32 eyes ) with primary open-angle glaucoma or ocular hypertension were all treated with Travoprost eyedrops once every night. The symptom score, Schirmer's test ( S Ⅰ t ) , corneal fluorescein staining ( FL ) , tear film break - up time (BUT), were observed before the treatment and 1, 2 and 3mo after the treatment.
RESULTS: The average symptom score, FL of all patients were 1. 34 ± 1. 56 and 0. 44 ± 0. 73 before the treatment, and 2. 75±1. 63, 1. 08±0. 84; 5. 10±1. 68, 1. 53±0-67;6. 33±1. 40, 1. 98±0. 50 respectively after 1, 2 and 3mo of the treatment. There was significant increase in symptom score and FL after the treatment for 1, 2 and 3mo (P=0. 00). The average BUT, SⅠt of all patients were (7. 76±0. 92s), (8. 47±2. 73mm/5min) before the treatment, and (7. 08±1. 15s), (7. 73±3. 44mm/5min);(5-59±1. 33s), (6. 82±3. 05mm/5min); (4. 29±1. 87s), (6-04±3. 15mm/5min) respectively after 1, 2 and 3mo of the treatment. There was significant decrease in BUT and ST after the treatment for 1, 2 and 3mo (P=0. 00).
CONCLUSION: Travoprost eyedrops can obviously aggravate patients’ corneal irritation after treatment. Our results show abnormal decreased tear secretion and stability of tear film induced by Travoprost eyedrops over the short term.

Background Retinal retinoic acid (RA) plays an important role in the formation of the lensinduced myopia.However,it is not clear how RA transfer the myopic signal to choroid throughout the retinal pigment epithelium (RPE) barrier.Objective The aim of this study was to investigate the effect of all-trans retinoic acid (atRA) on the barrier of RPE in lens-induced myopic eye of guinea pig.Methods Thirty left eyes of 30 21-dayold clean guinea pigs were randomized into normal control group and the model group.The models of out of focus were induced by covering of-6.00 D concave lens on the left eyes for 15 days.Radius of corneal curvature was measured using corneal curvimeter,and diopeter of the guinea pig was examined by mydriatic optometry.The length of ocular axis was detected by A-sonography.The animals were sacrificed and the retinas of the left eyes were isolated for the culture and passage of RPE cells.The third generation of cells were incubated Millcell-PET microporous film,and atRA at the concentration of 1 × 10-6,1 × 10-7,1 × 10-8 and 1 × 10-9 mol/L was added to the micropore respectively for 12 hours,and the micropores with equal-solvent served as negative control group.Methyl thiazolyl tetrazolium (MTT)colorimetric method was used to detect the survival rate of the cells.Subsequently,the transepithelial electrical resistance (TER) of the monolayer cells was determined with CN10-EVOM2 resistance measuring meter.The vesicular transport change of RPE membrane in different groups was evaluated by FM1-43 fluorescence staining.Results The mean diopter was (-2.20±0.95) D in the models,and that in the controls was (+ 1.15 ±0.30) D,with a significant difference between them (t =14.57,P＜ 0.01).The axial length was (8.24 ± 0.09) mm in the models and it was significantly longer than (7.81±0.05) mm in the controls (t=17.20,P＜0.01).RPE cells grew well to form a monolayer in Millcell culture pool after one week.After 24 hours of the atRA treatment,the survival rate of RPE cells reduced gradually with the increase of atRA concentration with the highest rate in the 1 × 10-9 mol/L atRA group (93.3 ％) and followed by the 1 × 10-8 mol/L atRA group (88.2％).More than half of the cells dead in the 1 × 10-6mol/L and 1 × 10-7mol/L atRA groups (53.8％ and 47.1％).Significant differences in the TER value and fluorescence staining intensity of the cells were seen among the various groups (F =43.89,P =0.00 ; F =26.13,P =0.00),with the maximal values in the 1 × 10-8mol/L atRA group.The FM1-43 fluorescence located on the cellular membrane and cytoplasm.Conclusions AtRA can increase the functional state of tight junction and vesicular transport,which regulated the RPE cell barrier in the guinea pig.

Abstract: Objective　To analyze the nucleic acid detection results of severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) by droplet digital PCR (ddPCR) and compare with the detection results of real-time fluorescence quantitative RT-PCR (qRT-PCR), so as to evaluate the advantages and disadvantages of detection, and to provide data support for optimizing the nucleic acid detection scheme of SARS-CoV-2. Methods　According to the SARS-CoV-2 specific primer probe published by the China Center for Disease Control and Prevention, a ddPCR detection method for SARS-CoV-2 was designed. One sample was selected for sensitivity test after gradient dilution; six respiratory virus nucleic acid positive samples including seasonal H3N2 influenza virus and SARS-CoV-2 positive samples were selected for specificity test; five SARS-CoV-2 positive samples were selected for repeatability test; in addition, 30 positive and 20 negative SARS-CoV-2 samples were selected for multiple clinical samples testing, and the results were analyzed and compared with those of qRT-PCR. Results　The ddPCR method can specifically detect SARS-CoV-2, and directly obtain the original copy number of the sample target gene to achieve accurate quantification; the sensitivity test of gradient dilution positive samples showed that qRT-PCR detected target genes in part of the 10-5 dilution of samples, and no target genes were detected in 10-6 dilution, while ddPCR detected all target genes in both 10-5 and 10-6 dilution of samples. The detection limit of ddPCR was two orders of magnitude higher than that of qRT-PCR, and the sensitivity was higher than that of qRT-PCR; in the comparison of the repeatability test results of the two methods, the coefficient of variation of ddPCR was 1.266%-11.814%, lower than 1.729%-26.174% of qRT PCR, and the repeatability was higher than qRT-PCR; among 50 clinical samples, 30 positive samples of confirmed cases of Coronavirus Disease 2019 (COVID-19) were detected by both methods, SARS-CoV-2 was successfully detected by both methods, and 20 negative samples of COVID-19 were detected by both methods, and the results were negative, with a coincidence rate of 100.00% (50/50). Conclusion　The ddPCR method can accurately quantify SARS-CoV-2 with strong specificity, and its sensitivity and repeatability are higher than those of qRT-PCR, but it also has certain detection limitations and is more suitable for the detection of low load samples. In the actual detection, the two methods can be reasonably combined to improve the detection accuracy.

Objective:To explore the method of establishing a modified demyelination and myelination regeneration model induced by dicyclohexanone oxalyl dihydrazone (CPZ) in mice with multiple sclerosis (MS), and to analyze the image markers of demyelination and myelination regeneration in mouse MS model.Methods:After the intragastrically administered with sodium carboxymethyl cellulose (CMCNa) for one week, a total of 30 C57BL/6 male mice were randomly divided into the control group ( n=10), the demyelination group ( n=10), and the remyelination group ( n=10). The mice of the control group were immediately performed MR scanning and pathological specimen obtaining; the mice in the demyelination group were administered with intragastrical CPZ-CMCNa once a day for 6 weeks for inducing demyelination, then received MR scanning and specimen obtaining with the same protocols used in control group; the mice in the remyelination group were administered with intragastrical CPZ-CMCNa once a day for six weeks for demyelination, then CPZ was withdrawn and normal diet was given for another four weeks. Then MR scanning and specimen obtaining were performed with the same protocols used in the other two groups. Regions of interest (ROIs) were set at the rostrum of corpus callosum (rCC), the bilateral normal appearing white matters (NAWM) of the rostrum of corpus callosum, and the bilateral cerebral cortex (Cx). The normalized T 2WI (T 2-normalized), fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) values were compared among the three groups by one-way ANOVA. Results:The demyelination and remyelination mice model of MS were successfully established. The T 2-normalized values of rCC in control group, demyelination group and remyelination group were 0.47±0.03, 0.72±0.04, 0.54±0.04, respectively, with statistically significant difference found ( F=90.511, P<0.05). Post-hoc multiple comparisons showed significant differences among those groups ( P<0.05). There was no significant difference of T 2-normalized value in NAWM and Cx among the three groups ( P>0.05). Moreover, there were significant differences in the FA values (0.36±0.04, 0.29±0.03, and 0.32±0.05), the MD values [(0.572±0.015), (0.598±0.034), and (0.626±0.043)×10 -3 mm 2/s], the AD values [(0.79±0.04), (0.77±0.06), and (0.83±0.04)×10 -3 mm 2/s], and the RD values [(0.46±0.02), (0.51±0.03), and (0.53±0.05)×10 -3 mm 2/s] of rCC of the control group, the demyelination group, and the remyelination group (all P<0.05). Significant difference was found in FA values between the demyelination group and the control group ( P<0.05), and in MD values between the remyelination group and the control group ( P<0.05), as well as in AD values between the remyelination group and the demyelination group ( P<0.05). There were also significant differences in RD values between the remyelination group and the control group, and the demyelination group and the control group (all P<0.05). However, no significant difference was found in all diffusion tensor imaging (DTI) metrics of NAWM and Cx among the three groups (all P>0.05). The LFB-eosin staining showed that the myelin sheath of rCC was lost in the demyelination group, and the rCC was partially regenerated and repaired in the remyelination group. Conclusion:The modified CPZ-CMCNa model can selectively induce demyelination and remyelination of rCC, and the changes of demyelination and remyelination of rCC in the modified CPZ-CMCNa model can be quantitatively detected by T 2WI combined with DTI, which might provide related theoretical basis for the study on dynamic changes of MS lesions.