Clinical analysis of P2Y2 receptor agonist in the treatment of diabetic dry eye / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the clinical efficacy of P2Y2 agonist diquafosol sodium(DQS)eye drops in the treatment of diabetic dry eye.METHODS: A total of 80 patients(160 eyes)with diabetic dry eye who admitted to our hospital from January 2022 to March 2022 were selected. They were randomly divided into study group and control group. A total of 40 patients(80 eyes)in the study group were treated with 3% DQS eye drops and 40 patients(80 eyes)in the control group were treated with 0.3% sodium hyaluronate eye drops. The ocular surface disease index(OSDI)score, non-invasive tear meniscus height(NITMH), first non-invasive tear film break-up time(NIBUTf), average non-invasive tear film break-up time(NIBUTav), tarsal gland loss score, lipid layer thickness grade and bulbar redness analysis(including conjunctival grade and ciliary grade), were examined before treatment and at 1wk, 1 and 3mo after treatment, respectively. Furthermore, corneal fluorescence staining and conjunctival lissamine green staining were analyzed based on the ocular surface staining score(OSS), and the conjunctival impression cytology and confocal microscopy were evaluated before and 3mo after treatment, respectively.RESULTS: There were no differences in OSDI score, tarsal gland loss score, conjunctival grade score and ciliary grade score between the two groups before and after treatment(P>0.05). OSS scores in the study group were lower than those in the control group, while NITMH, NIBUTf and NIBUTav were higher than those in the control group at 1 and 3mo after treatment(P<0.05). After 3mo of treatment, the density of conjunctival goblet cells increased and corneal dendritic cells decreased in the study group compared with the baseline(all P<0.05), while there were no significant changes in the control group compared with the baseline(all P>0.05).CONCLUSION: 3% DQS eye drops were effective in treating diabetic dry eye without serious complications.

Safety and efficacy of lacrimal canalicular plug in the treatment of severe chronic ocular graft-versus-host disease / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the safety and efficacy of lacrimal canalicular plug in the treatment of severe chronic ocular graft-versus-host disease(coGVHD).METHODS: Retrospective study. A total of 9 patients with severe coGVHD admitted to the dry eye clinic of the Affiliated Hospital of Xuzhou Medical University from June to September 2022 were included. All patients underwent binocular inferior lacrimal canaliculus plug. Ocular surface disease index(OSDI)score, tear meniscus height(TMH), corneal fluorescein staining(CFS)scores, conjunctival lisamine green staining(CLGS)score, noninvasive breakup time(NIBUT), Schirmer Ⅰ test(SⅠt)and the infiltration of Langerhans cells in the superficial corneal stroma tested by confocal corneal microscopy were observed before treatment and at 1 and 3 mo after treatment. At the same time, the complications related to lacrimal canalicular plug implantation were evaluated.RESULTS: The OSDI score decreased from 67.33±12.64 before treatment to 21.89±6.07 after 3mo of treatment(P<0.01); TMH increased from 0.09±0.02mm to 0.21±0.03mm after 3mo of treatment(P<0.05), and NIBUT increased from 2.24±0.68s before treatment to 6.77±2.05s after 3mo of treatment(P<0.01). In addition, the CFS and CLGS also changed significantly, from 9.11±1.45 and 6.33±1.00 before treatment to 2.22±0.67 and 2.56±0.88 at 3mo after treatment, respectively(all P<0.01). The density of Langerhans cells decreased from 140.22±38.18cells/mm2 before treatment to 39.67±9.75cells/mm2 3mo after treatment(P<0.01). SⅠt showed no significant difference before and after treatment(F=0.059, P=0.943). During the whole follow-up period, no complications such as plug abscission were observed.CONCLUSION: Lacrimal canalicular plug is safe and effective in the treatment of severe coGVHD. It can significantly improve the symptoms and signs of dry eye patients and reduce inflammatory reaction.

Analysis of interleukin-36 expression in tears of allogeneic hematopoietic stem cell transplantation patients and its correlation with the ocular surface microenvironment / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To detect the expression of interleukin(IL)-36(α, β, γ)in tears of patients undergoing allogeneic hematopoietic stem cell transplantation(allo-HSCT), investigate its correlation with ocular surface microenvironment, and further analyze the relationship between its expression and ocular graft-versus-host disease(oGVHD).METHODS: Prospective study. A total of 35 patients(70 eyes)underwent allo-HSCT in the hematology department of our hospital in January 2020 were selected, and 35 healthy volunteers(70 eyes)with appropriate age and gender were selected as normal control group. The patients in the allo-HSCT group were followed up 3 times after operation once every 3mo. The subjects with postoperative ocular symptoms were divided into oGVHD and Non-oGVHD group.Ocular surface disease index(OSDI)questionnaire, Schirmer test, tear break-up time(TBUT), corneal fluorescein staining(FL), and conjunctival impression cytology(CIC)was conducted in three groups. Furthermore, the expression levels of IL-36(α,β,γ)in tears were detected by ELISA.RESULTS: In the normal control group, IL-36(α, β, γ)expression levels were 74.32±5.27, 70.02±8.43, 97.41±8.66 pg/mL, respectively; in the allo-HSCT group, IL-36(α, β, γ)baseline expression levels were 77.27±7.03, 74.53±7.53, 100.77±9.74 pg/mL, with no statistically significant differences between the two groups(t=1.648, 1.954, 1.262, all P>0.05). There were no significant differences in IL-36α, IL-36β and IL-36γ in Non-oGVHD group at different time points(P>0.05), while there were significant differences in IL-36α, IL-36β and IL-36γ in oGVHD group at different time points(P<0.05). Compared with Non-oGVHD group, the levels of IL-36α and IL-36β at different time points were significantly increased in oGVHD group(all P<0.05).IL-36(α, β, γ)of oGVHD group was positively correlated with OSDI score, FL and CIC, while it was negatively correlated with TBUT and Schirmer test(all P<0.05).CONCLUSION: Evaluation of levels of tear IL-36(α, β, γ)can be of significance in diagnosing oGVHD after allo-HSCT. IL-36(α, β, γ)is highly expressed in the tears of oGVHD patients before the onset of ocular symptoms, and it is correlated with the ocular surface parameters.

Safety and efficacy of intense pulsed light in the treatment of severe chronic ocular graft-versus-host disease / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the safety and efficacy of intense pulsed light in the treatment of severe chronic ocular graft-versus-host disease.METHODS: Prospective randomized controlled study. A total of 35 cases(35 eyes), who had a history of allogenic hematopoietic stem cell transplantation(allo-HSCT), admitted to the Affiliated Hospital of Xuzhou Medical University from January to September 2022 and were diagnosed by our hospital's hematology and ophthalmology departments with severe chronic ocular graft-versus-host disease(coGVHD)were selected. One eye was randomly selected for inclusion in the study if both eyes met the enrollment criteria, and the eye was selected if a single eye met the enrollment criteria. All patients were administrated with Dextran and Hypromellose eye drops 4 times a day and Cyclosporine eye drops twice a day. The experimental group was additionally treated with intense pulsed light, once every two weeks a week, for 4 times in total. The evaluation indicators were evaluated before treatment and 2wk, 1 and 2mo after treatment. The evaluation indicators include ocular surface disease index(OSDI)score, best corrected visual acuity(BCVA), intraocular pressure(IOP), tear meniscus height(TMH), non-invasive break-up time(NIBUT), conjunctival injection score(CIS), meibomian gland area proportion(MGAP), meibomian gland evaluation(MGE), cornea fluorescein staining(CFS), conjunctival lissamine green staining(CLGS), lid margin abnormality score(LMAS), and Schirmer's Ⅰ test(SⅠt).RESULTS: After treatment, OSDI score, TMH, NIBUT, BCVA, CFS, CLGS, and CIS improved in both groups compared with those before treatment(all P<0.05), with NIBUT, CFS and CLGS showing more significant improvements in the test group. In the control group, MGAP, MGE of the upper and lower eyelids and LMAS did not change significantly before and after treatment(P>0.05), while in the experimental group, MGAP of the lower eyelids, MGE of upper and lower eyelids and LMAS improved compared with those before treatment(P<0.05), except for MGAP of the upper eyelids, which did not differ from that before treatment(P>0.05). There was no difference in SⅠt and IOP between the two groups before and after treatment(P>0.05). Patients did not experience adverse reactions such as skin burns, redness and swelling in the treated area and eyelash loss during the follow-up period.CONCLUSION: Intense pulsed light is safe and effective in the treatment of severe coGVHD, which can significantly improve the symptoms and signs of patients and enhance the stability of tear film.

Clinical Value of 1.5-T Non-contrast Whole-heart Magnetic Resonance Coronary Angiography in Evaluating the Severity of Coronary Stenosis / 中国医学科学院学报

Objective To evaluate the diagnostic performance of 1.5-T non-contrast free-breathing whole-heart magnetic resonance coronary angiography(MRCA)for≥50% and≥70% coronary artery stenosis in coronary artery disease(CAD).Methods Forty-one patients clinically scheduled for invasive coronary angiography(ICA)underwent 1.5-T non-contrast free-breathing whole-heart MRCA.The diagnostic performance for≥50% and≥70% stenosis was evaluated and compared using ICA as a reference standard.Results MRCA was completed in all the 41 patients with the total acquisition time of(10.1 ± 2.2)min.The sensitivity,specificity,and accuracy of MRCA for≥50% and≥70% stenosis were 100%(95%

Feasibility of Non-contrast-enhanced Coronary Magnetic Resonance Angiography at 3.0T / 中国医学科学院学报

To evaluate the feasibility of non-contrast-enhanced magnetic resonance angiography (NCE-MRA) on a 3.0T scanner. Totally 36 volunteers and 24 patients with clinically suspected coronary artery disease underwent NCE-MRA. The quality of the NCE-MRA images was graded for each segment on a four-point scale. The subjects were divided into two groups according to image quality. The age,body mass index (BMI),heart rate,end-expiratory diaphragm displacement,and respiratory diaphragm motion amplitude were evaluated and compared. The average image quality score of every segment was above 2 points. The proximal and middle segments of left anterior descending artery had significantly higher quality scores than the distal segments (=0.000) and the proximal segment of left circumflex coronary artery had significantly higher quality scores than the distal segments (=0.000),the proximal segment of right coronary artery also had a significant higher quality score than its distal segment (=0.001). The image quality was good in 38 subjects (64.4%). The heart rate [(66.35±9.39) beat/min (75.32±11.67) beat/min] (=0.002) and the body mass index [(24.72±3.33) kg/m (27.82±3.61) kg/m ] (=0.002) were significantly different between the good image quality group and the poor image quality group. The end-expiratory diaphragm displacement in good image quality group was (4.43±2.07)mm,which was significantly lower than that in poor image quality group [(9.26±7.62)mm](=0.013). The respiratory diaphragm motion amplitude [(21.35±6.02) mm] in good image quality group was significantly lower than that in poor image quality group [(30.68±14.20)mm](=0.012). NCE-MRA on 3.0T is a feasible tool for visualization of the proximal and middle segments of coronary arteries,and the image quality can be optimized by controlling heart rate and respiration in the future.

Feedback analysis of integrated medical imaging training on cultivating medical students / 基础医学与临床

Objective To investigate the effects and acceptability of introducing integrated medical imaging training on cultivating medical students. Methods Thirty-two postgraduate students, doctoral candidates and junior resi-dents gave feedback from 2015 to 2017.Analysis of those appraisements to understand the perspective and satisfac-tion of medical students on imaging learning and practicing.Results The results showed that integrated medical im-aging training helps a lot in improving learning initiative and efficiency,strengthening the clinical application of bas-ic medical knowledge for medical students. Conclusions Using innovative methods to improve teaching mode is promising for promoting the effectiveness of medical students' cultivation.

Application of the Dual-layer Spectral Detector CT in the CT Angiography of Superior Vena Cava / 中国医学科学院学报

Objective To evaluate the application of the dual-layer spectral detector CT in the CT angiography of superior vena cava (SVC). Methods Totally 30 consecutive patients who underwent chest enhanced CT in our center were enrolled in this study. Eight series of images were reconstructed,including the conventional images at 120 kVp and seven series of virtual monoenergetic spectral images at 40,50,60,70,80,90,and 100 keV. The regions of interest (ROIs) were placed at the level of the proximal end,middle part,and distal end in the SVC vessel. The CT values and standard deviations of these three ROIs and the lipid on prothroax wall were measured. The signal to noise ratio (SNR),contrast to noise ratio (CNR),and effective dose (ED) were calculated. In addition,the quality of images was evaluated by two blinded readers using a grading scheme. The differences in CT values,SNR,and CNR among groups were analyzed using the independent t-test. The quality of all images was compared using non-parametric test between two readers,and the consistency between two radiologists were evaluated by using Kappa (κ) value. Results There was no significantly different attenuation value among three ROIs of the SVC for each monoenergetic images (all P>0.05). The SVC showed significantly higher attenuation value (223.51±40.35)HU,SNR 13.56±4.18 and CNR 24.15±6.58 in the 40 keV group than in other keV groups and the conventional group [attenuation value:(97.70±13.85)HU;SNR:4.59±1.41;CNR:9.69±2.81] (P<0.005). The mean ED was(2.04±0.63) mSv. The subjective diagnostic scores accessed from two radiologists were 1 (1,2) and 1 (1,2) (Z=-0.358,P=0.720). The subjective diagnostic quality values evaluated by two observers showed excellent consistency (κ=0.863,P=0.000). Conclusion An optimal imaging of the SVC can be achieved on monoenergetic reconstructions at 40 keV by using the dual-layer spectral detector CT.

Clinical Application and Research Advances of CT Myocardial Perfusion Imaging / 中国医学科学院学报

Computed tomography (CT)-based myocardial perfusion imaging (CTP)has been widely recognized as a one-station solution for the imaging of myocardial ischemia-related diseases. This article reviews the clinical scanning protocols,analytical methods,and research advances of CTP in recent years and briefly discusses its limitations and future development.

Application of Reporter Gene Labeling in Stem Cell Therapy for Acute Myocardial Infarction / 中国医学科学院学报

Stem cell therapy for acute myocardial infarction is drawing great attention. However,the biological behavior and function mechanism of implanted stem cells remain controversial, as well as their clinical benefits. With the development of imaging probes and devices, molecular imaging enables noninvasive, dynamic tracking of stem cells in vivo. In this review, we summarize the use of various markers,especially the technique of reporter gene labeling, in the field of stem cell therapy, and highlight some recent preclinical and clinical achievements.

Value of dual-source computed tomography angiography of coronary artery for preoperative evaluation of old patients scheduled for noncardiac surgery / 中国医学科学院学报

<p><b>OBJECTIVE</b>To assess the role of computed tomography angiography (CTA) using dual-source computed tomography in the preoperative evaluation of old patients scheduled for noncardiac surgery.</p><p><b>METHODS</b>A retrospective review of the clinical data of patients who underwent CTA in our hospital between May 2011 and May 2013 was performed, and totally 111 old patients with risk factors of coronary artery diseases scheduled for noncardiac surgery were found to coronary CTA for preoperative evaluation. Prospectively electrocardiograph-triggered sequence scan protocol with dual-source computed tomography was performed. The imaging quality, coronary artery stenosis, the treatment before operation, and perioperative complications were assessed.</p><p><b>RESULTS</b>For 1 779 coronary artery segments in 111 patients, the number of evaluable segments was 1 676 (97.4%). The mean effective dose of CTA was (2.7 ± 0.9) mSv. Among them, 71 patients with coronary artery stenosis <50% underwent surgery without cardiac complication and 17 patients with coronary artery stenosis ≥ 70% underwent conventional coronary angiography and coronary angioplasty or bypass surgery. The sensitivity and specificity of CTA in detecting ≥ 50% stenosis were 95% and 96%, and the sensitivity and specificity of CTA in detecting ≥ 70% stenosis were 97% and 98%. For 19 patients with coronary artery stenosis between 50% and 70%, the levels of myocardial enzyme were transiently higher for two patients, and no other cardiac complication occurred.</p><p><b>CONCLUSION</b>Coronary artery CTA is reliable in artery stenosis evaluation and can be used as cardiac risk stratification for old patients scheduled for noncardiac surgery.</p>

128-slice Dual-source Computed Tomography Coronary Angiography in Patients with Atrial Fibrillation: Image Quality and Radiation Dose of Prospectively Electrocardiogram-triggered Sequential Scan Compared with Retrospectively Electrocardiogram-gated Spiral Scan / 中国医学科学杂志(英文版)

Objective To evaluate the image quality (IQ) and radiation dose of 128-slice dual-source computed tomography (DSCT) coronary angiography using prospectively electrocardiogram (ECG)-triggered sequential scan mode compared with ECG-gated spiral scan mode in a population with atrial fibrillation. Methods Thirty-two patients with suspected coronary artery disease and permanent atrial fibrillation referred for a second-generation 128-slice DSCT coronary angiography were included in the prospective study. Of them, 17 patients (sequential group) were randomly selected to use a prospectively ECG-triggered sequential scan, while the other 15 patients (spiral group) used a retrospectively ECG-gated spiral scan. The IQ was assessed by two readers independently, using a four-point grading scale from excel-lent (grade 1) to non-assessable (grade 4), based on the American Heart Association 15-segment model. IQ of each segment and effective dose of each patient were compared between the two groups. Results The mean heart rate (HR) of the sequential group was 96±27 beats per minute (bpm) with a variation range of 73±25 bpm, while the mean HR of the spiral group was 86±22 bpm with a variationrange of 65±24 bpm. Both of the mean HR (t=1.91, P=0.243) and HR variation range (t=0.950, P=0.350) had no significant difference between the two groups. In per-segment analysis, IQ of the sequential group vs. spiral group was rated as excellent (grade 1) in 190/244 (78%) vs. 177/217 (82%) by reader1 and 197/245 (80%) vs. 174/214 (81%) by reader2, as non-assessable (grade 4) in 4/244 (2%) vs. 2/217 (1%) by reader1 and 6/245 (2%) vs. 4/214 (2%) by reader2. Overall averaged IQ per-patient in the sequential and spiral group showed equally good (1.27±0.19 vs. 1.25±0.22, Z=-0.834, P=0.404). The effective radiation dose of the sequential group reduced significantly compared with the spiral group (4.88±1.77 mSv vs. 10.20±3.64 mSv; t=-5.372, P=0.000). Conclusion Compared with retrospectively ECG-gated spiral scan, prospectively ECG-triggered sequential DSCT coronary angiography provides similarly diagnostically valuable images in patients with atrial fibrillation and significantly reduces radiation dose.

Effect of hydrogen peroxide with different pH values on the color, translucency and laser-induced fluorescence of human dentin / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of 30% hydrogen peroxide(HP) with different pH values on color, translucency and laser-induced fluorescence of human dentin.</p><p><b>METHODS</b>Sixty dentin specimens from crown of mandibular third molars were randomly assigned into four groups (n = 15) and treated with acidic 30% HP, neutral 30% HP, alkaline 30% HP and deionized water (control group), respectively. The bleaching process was 0.5 h×4 times, and time points for measuring were baseline (0), 0.5, 1 and 2 h. A colorimeter was employed to measure the L(*), a(*), b(*) coordinates of dentin against white, black and yellow background. Then the parameters of translucency, masking effects, chroma and whiteness were calculated. The dentinal laser-induced Raman/fluorescence spectra was recorded by a Raman spectrometer and the fluorescence intensity(FI) and FI% were calculated.</p><p><b>RESULTS</b>ΔFI of acidic, neutral, alkaline 30% HP at 2 h were 9960.03 ± 2037.74, 8502.09 ± 1413.86, 8554.29 ± 1986.19. And ΔFI% were 84.60 ± 3.43, 84.89 ± 5.19, 86.72 ± 2.65, respectively. Repeated measure of ANOVA revealed that all parameters in the bleaching groups were significantly influenced by time (P < 0.001). Compared with control group, bleaching resulted significant change of ΔTP, Δchroma, Δwhiteness, ΔL(*), Δa(*), Δb(*), ΔE, ΔFI and ΔFI% (P < 0.001). There was no significant difference between three bleaching groups on ΔTP, Δmasking effects, Δchroma, Δwhiteness, ΔL(*), Δb(*), ΔE, ΔFI and ΔFI%. Correlation analysis demonstrated that FI was associated with chroma, a(*), b(*) and whiteness, respectively, and ΔFI was associated with ΔTP, Δmasking effects, Δwhiteness, Δchroma, Δb(*) and ΔE.</p><p><b>CONCLUSIONS</b>30% HP with different pH values could result in the same change of the color, translucency and laser-induced fluorescence of human dentin.Laser-induced fluorescence was associated with dentinal color and translucency, which might be a novel way to investigate the bleaching mechanism of dentin.</p>

Three-dimensional finite element analysis of removable partial denture with periodontally compromised abutments / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate three-dimensional (3D) finite element (FE) modeling of different periodontally compromised unilateral distal extension removable partial denture (RPD) abutments using the data of a 3D non-contact digitizing scanner.</p><p><b>METHODS</b>FE models were established, and the following structures were simulated in the models: alveolar bone, mucosa, abutments, periodontal ligaments, framework and artificial teeth. The alveolar bone and periodontal ligaments around the distal abutment in the three models were designed as normal, with bone defect and with periodontal ligaments defect respectively.Vertical or buccally inclined forces of 50, 100, 100 N were applied on the artificial teeth of the RPD and the stress distributions on the supporting tissues were calculated.</p><p><b>RESULTS</b>Under vertical loading, the maximal stress on the alveolar bone of the abutment were as follows: periodontal ligaments defect model (3.57 MPa) > bone defect model (3.21 MPa) > normal model (2.63 MPa). Under buccally inclined loading, the maximal stress on the alveolar bone of the abutment were as follows: periodontal ligaments defect model (2.50 MPa) > bone defect model (2.41 MPa) > normal model (1.79 MPa). Under buccally inclined loading, the stresses on distal aspects of the residual alveolar ridge were higher than that of the vertical loading model.</p><p><b>CONCLUSIONS</b>3D non-contact digitalizing scanner was useful for the finite element modeling process of removable partial denture.</p>

In vivo and in vitro imaging tracing of dual-labeled bone mesenchymal stem cells transplanted into myocardium of F344 rats / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the feasibility of in vitro and in vivo magnetic resonance imaging (MRI) and fluorescence imaging tracking of transplanted bone mesenchymal stem cells (BMSCs) dual-labeled with ultrasmall superparamagnetic iron oxide (USPIO) and red fluorescence protein (RFP).</p><p><b>METHODS</b>BMSCs were incubated with culture medium containing USPIO for 24 hours. The Prussian-blue staining, transmission electron microscopy and trypan-blue staining were used to study the efficacy and safety of labeling. F344 rat model of acute myocardial infarction was established by ligating the left anterior descending coronary artery. The dual-labeled BMSCs were injected into the margin of the infraction myocardium. Then MRI and fluorescence imaging were performed to trace the cells both in vitro and in vivo. Postmortal study was carried out to observe the distribution of transplanted cells in myocardium.</p><p><b>RESULTS</b>The percentage of dual-labeled BMSCs reached 99% after co-incubating with USPIO for 24 hours. USPIO particles were mainly located in lysosomes. As demonstrated by trypan-blue staining, there was no significant deference in viability between labeled and unlabeled groups (P>0.05). All dual-labeled transplanted BMSCs showed a significant decreasing signal on MRI, and the signal intensity changes had no significant difference over 4 weeks (P=0.66). In vitro cell tracing with fluorescence imaging of isolated heart from F344 rats was successful,while in vivo cell tracing with fluorescence imaging failed. Prussian blue staining showed that USPIO distributed near the infarcted myocardium, corresponding with the fluorescence imaging.</p><p><b>CONCLUSION</b>MRI can be used to trace the dual-labeled BMSCs transplanted into F344 rat hearts in vivo, while fluorescence imaging and pathological fluorescence imaging can trace the transplanted cells in vitro.</p>

Effects of three at-home bleaching agents on enamel structure and structure-related mechanical properties / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of three differently concentrated at-home bleaching agents on the structure and the structure-related mechanical properties of human enamel.</p><p><b>METHODS</b>Sixty enamel specimens were randomly divided into four groups and treated with 10% carbamide peroxide (CP), 15% CP, 20% CP and distilled water, respectively. The bleaching process was 8 h/day for 14 consecutive days. Baseline and final atomic force microscopy (AFM) surface detection, Raman spectroscopy, attenuated total reflectance-infrared spectroscopy (ATR-IR), microhardness and fracture toughness (FT) measurements were carried out before and after bleaching experiments.</p><p><b>RESULTS</b>CP didn't change the morphology of enamel. Meanwhile, the three bleached groups and the control group had no significant difference in root mean square detection (P = 0.774), ν(2)CO(3)(2-) : ν(1)ν(3)PO(4)(3-) (P = 0.263) and microhardness (P = 0.829). The percentage of relative Raman intensity in the three bleached groups and the control group were (105.74 ± 11.34)%, (104.46 ± 8.83)%, (99.52 ± 9.32)% and (97.62 ± 7.46)%, respectively. There was no significant difference among them (P = 0.062). However, the percentage of laser-induced fluorescence in the three bleached groups and the control group were (20.86 ± 7.23)%, (22.14 ± 7.34)%, (21.10 ± 7.59)% and (100.78 ± 3.70)%, respectively. There was significant difference between either of the bleached groups and the control group (P < 0.001). Moreover, FT declined significantly in the three groups (P = 0.024, P = 0.005, P = 0.013) when compared with the control group.</p><p><b>CONCLUSIONS</b>Under in vitro condition, three differently concentrated at-home bleaching agents wouldn't induce the demineralization and the decline of microhardness on enamel. However, the decrease of FT on enamel seemed to be inevitable after bleaching.</p>

Effects of try-in paste and luting agent on the resultant color of all-ceramic veneers / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The purposes of this study was to investigate the effects of luting agents on the resultant color of IPS e.max all-ceramic veneer restorations, and to evaluate the similarity of try-in pastes and the corresponding luting agents on the final color.</p><p><b>METHODS</b>Disc-shaped ceramic specimens were fabricated and seated on four shades of resin specimens to mimic the complex of ceramic veneer laying on tooth substrates. Try-in pastes and luting agents (Shades of TR, B0.5, A1, A3, W0) were applied into the inter-layer of ceramic and resin specimens, respectively. The color of the combinations was measured using a spectrophotometer and subsequently converted to CIE L*a*b* values. Color changes after luting agent applied, and between try-in paste and corresponding luting agent were calculated and registered as DeltaEresin and DeltaEpaste-resin.</p><p><b>RESULTS</b>DeltaEresin value of A2, A3 backgrounds was more than 1.0. DeltaEresin value of A4, A5 backgrounds was less than 1.0. The DeltaEpaste-resin value of A3 backgrounds was more than 1.0, whereas, A2 was less than 1.0 (except for shade W0). The DeltaEpaste-resin value of shade W0 was significantly different from other shades of luting agents.</p><p><b>CONCLUSION</b>The color of ceramic veneer restorations were affected by luting agents with A2, and A3 background colors. The agreement of the try-in paste and the corresponding luting agent was excellent for A2 background (except for W0).</p>

Coronary computed tomographic angiography using low-dose prospectively electrocardiographic triggered high-pitch spiral acquisition by dual-source computed tomography: image quality and radiation dose / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate image quality (IQ) and radiation exposure of coronary computed tomographic angiography (CTA) with prospectively electrocardiographic (ECG) triggered high-pitch spiral acquisition using dual source CT.</p><p><b>METHODS</b>Totally 75 consecutive patients with a stable heart rate (HR) ≤65 bpm underwent coronary CTA. patients were divided into two groups according to their HR (group A HR≤60 bpm, group B HR >60 bpm to≤65 bpm) . A dual-source CT scanner was used (0.6mm collimation, 0.28s rotation time, 80~100 kV, 370 mAs/rot) . Data acquisition was prospectively ECG-triggered at 60% of the R-R interval with a pitch of 3.4. Images were reconstructed with 75ms temporal resolution, 0.75mm slice thickness and 0.5mm increment. IQ was evaluated using a four-point scale (1=excellent, 4=unevaluable) .</p><p><b>RESULTS</b>The mean HR and scan time of all patients was (57.2 ± 4.8) bpm and (0.42 ± 0.02) s. Of 1103 coronary artery segments, 934 (84.7%) had an IQ score of 1, 135 (12.2%) score of 2, 18 (1.6%) score of 3,and 16 (1.5%) were rated as unevaluable. There was no significant difference between the two groups in IQ [mean score (1.19 ± 0.52 vs. 1.22 ± 0.55;Z=-1.107,P=0.268) . The rate of evaluable segments showed no significant difference between the two groups (98.5% vs. 98.6%;X2=0.000,P=1.000) . Mean dose-length product of all patients was (67.2 ± 30.4) mGy × cm, mean effective dose was (0.94 ± 0.43) mSv.</p><p><b>CONCLUSION</b>In patients with a stable HR of 65 bpm or less, prospectively ECG-triggered high-pitch spiral CT acquisition provides high IQ at low radiation dose.</p>

Assessment of coronary stent lumen visibility and patency by dual-source computed tomographic angiography / 中国医学科学院学报

<p><b>OBJECTIVE</b>To assess the in-stent lumen visibility and image quality of coronary stents by dual-source computed tomography (DSCT) coronary angiography, and the diagnostic accuracy of DSCT in the detection of coronary in-stent restenosis.</p><p><b>METHODS</b>DSCT was performed at 147 stents in 78 patients at an interval of (21.8?22.2) months after coronary stent implantation. Axial multi-planar reconstruction of the stents and curved-planar reconstruction through the median of the stents were evaluated for stent image quality on a 5-point scale, and the stent lumen diameters were detected. Thirty out of these 78 patients underwent conventional coronary angiography within one month after CT angiography. The patency of 60 stents were independently evaluated by two blinded readers.</p><p><b>RESULTS</b>Image quality was good to excellent on average score (1.6?0.6) . Stent image quality score was correlated with stent diameter, stent location, and heart rate. All stents were assessable in lumen visibility with an average visible lumen diameter percentage of (72.2?12.2) %. Visible lumen diameter percentage was correlated with stent diameter and stent location. For the stents with calcified plaques, the visible lumen diameter percentage at the calcified site was significantly lower than that at the non-calcified site (P<0.001) . Compared with the conventional coronary angiography, 12 out of 14 in-stent stenoses were correctly detected. The sensitivity, specificity, positive predictive value, and negative predictive value for the detection of in-stent stenosis was 85.7%, 95.7%, 85.7%, and 95.7%, respectively. For stents whose diameter >0.275cm, the sensitivity, specificity, positive predictive value, and negative predictive value were all 100%. The agreement between CT findings and coronary angiography results was 93.3%, and it was correlated with stent diameter and heart rate.</p><p><b>CONCLUSIONS</b>Using a DSCT, coronary stent lumen is partially visible and the image quality is high. Stent diameter and location can influence the stent lumen visibility and image quality. DSCT has a high diagnostic accuracy for the detection of in-stent restenosis and may be a valuable modality for the follow-up of coronary artery stent patency."</p>

Comparison of prospectively electrocardiographic triggered spiral and sequential acquisition for coronary computed tomographic angiography using dual-source computed tomography / 中国医学科学院学报

<p><b>OBJECTIVE</b>To compare the image quality and radiation dose of prospectively electrocardiogram (ECG) -triggered spiral and sequential acquisition for coronary computed tomographic angiography by dual-source computed tomography.</p><p><b>METHODS</b>Sixty patients with suspected or known coronary artery disease were randomly divided into two groups. Group A underwent prospective ECG-triggering spiral scan and Group B underwent prospective ECG-triggering sequential scan. Both the image quality and radiation dose of the two groups were compared.</p><p><b>RESULTS</b>There was no significant difference in age and body mass index of the two groups. The average image quality score was 1.12 ± 0.38 in group A and 1.14 ± 0.38 in group B (Z=-0.291,P=0.771) . The rates of diagnostic coronary segments for two groups were 98.87% and 99.56% respectively (X2=0.59,P=0.443) . The mean radiation dose of group A was significantly lower than that of group B [ (1.31 ± 0.30) mSv vs. (3.36 ± 0.93) mSv; t=11.47, P=0.000] .</p><p><b>CONCLUSION</b>Compared with the prospective ECG-triggered sequential acquisition, the prospective ECG - triggered spiral scan for coronary computed tomographic angiography can remarkably reduce radiation dose without impairing image quality in patients with a low and stable heart rate (≤ 70 bpm) .</p>