Estimating Postmortem Interval Using Intestinal Microbiota Diversity Based on 16S rRNA High-throughput Sequencing Technology / 法医学杂志

OBJECTIVES@#To explore the correlation between intestinal microbiota and postmortem interval(PMI) in rats by using 16S rRNA high-throughput sequencing technology.@*METHODS@#Rats were killed by anesthesia and placed at 16 ℃, and DNA was extracted in caecum at 14 time points of 0, 1, 2, 3, 5, 7, 9, 12, 15, 18, 21, 24, 27 and 30 d after death. The 16S rRNA high-throughput sequencing technology was used to detect intestinal microbiota in rat cecal contents, and the results were used to analyze the rat intestinal microbiota diversity and differences.@*RESULTS@#The total number of intestinal microbial communities did not change significantly within 30 days after death, but the diversity showed an upward trend. A total of 119 bacterial communities were significantly changed at 13 time points after death. The models for PMI estimation were established by using partial least squares (PLS) regression at all time points, before 9 days and after 12 days, reaching an R2 of 0.795, 0.767 and 0.445, respectively; and the root mean square errors (RMSEs) were 6.57, 1.96 and 5.37 d, respectively.@*CONCLUSIONS@#Using 16S rRNA high-throughput sequencing technology, the composition and structure of intestinal microbiota changed significantly within 30 d after death. In addition, the established PLS regression model suggested that the PMI was highly correlated with intestinal microbiota composition, showing a certain time series change.

Effects of femtosecond laser treatment on surface characteristics and flexural strength of zirconia / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the effects of femtosecond laser treated microgrooved surface on microscopic topography, phase transformation, and three-points flexural strength of zirconia, and to provide reference for surface microstructure optimization of zirconia implant.@*METHODS@#According to different surface treatment methods, 57 computer aided design/computer aided manufacture (CAD/CAM) zirconia bars (20.0 mm×4.0 mm×1.4 mm) were evenly divided into three groups: sintered group, no treatment after sintering, taken as control; sandblasted group, sandblasted with 110 μm aluminium oxide (Al2O3) after sintering; microgrooved group, femtosecond laser fabricated microgrooves with 50 μm width, 30 μm depth, and 100 μm pitch. Surface microscopic topography was observed with scanning electron microscope (SEM) and 3D laser microscope. Further, surface roughness in each group and microgroove size were measured. Crystal phase was analyzed with X-ray diffraction. Specimens were subjected to three- points flexural strength test, and Weibull distribution was used to analyze their strength characteristics.@*RESULTS@#SEM showed that sintered surface was flat with clear grain structure; sandblasted surface exihibited bumps and holes with sharp margins and irregular shape; microgrooves were regularly aligned without evident defect, and nano-scale particles were observed on the surface inside of the microgrooves. Ra value of microgrooved group [(9.42±0.28)] μm was significantly higher than that of sandblasted group [(1.04±0.03) μm] and sintered group [(0.60±0.04) μm], and there was statistical difference between sandblasted group and sintered group (P < 0.001). The microgroove size was precise with (49.75±1.24) μm width, (30.85±1.02) μm depth, and (100.58±1.94) μm pitch. Crystal phase analysis showed that monoclinic volume fraction of sandblasted group (18.17%) was much higher than that of sintered group (1.55%), while microgrooved group (2.21%) was similar with sintered group. The flexural strength of sandblasted group (986.22±163.25) MPa had no statistical difference with that of sintered group (946.46±134.15) MPa (P=0.847), but the strength in microgrooved group (547.92±30.89) MPa dropped significantly compared with the other two groups (P < 0.001). Weibull modulus of sintered, sandblasted, microgrooved groups were 7.89, 6.98, and 23.46, respectively.@*CONCLUSION@#Femtosecond laser was able to form micro/nanostructured microgrooves on zirconia surface, which deleteriously affected the flexural strength of zirconia.

Estimating Postmortem Interval by Protein Chip Detection Technology Combined with Multidimensional Statistics / 法医学杂志

Objective To obtain the protein expression profile of rat liver tissue after death by the 2100 bioanalyzer combined with protein chip, and infer the relationship between protein expression profile and postmortem interval. Methods Rats were killed by abdominal anesthesia and placed at 16 ℃. Water-soluble proteins in liver tissues were extracted at 14 time points after death. The expression profile data of proteins with relative molecular weight of 14 000-230 000 were obtained using protein chip, and principal component analysis （PCA）, partial least squares-discriminant analysis （PLS-DA） and Fisher discriminant were used to analyze the data. Results According to the changes of protein expression profile, the postmortem interval was divided into group A （0 d）, group B （1-9 d）, group C （12-30 d） according to the result of PLS-DA. The prediction accuracy of the training set and test set of the model were all 100.0%, and the internal cross-validation of the training set was 100.0% according to Fisher discriminant. The Fisher discriminant model at each time point of group B and C was established to narrow the time window of postmortem interval estimation. The prediction accuracy of the training set and test set were all 100.0%, and the internal cross-validation accuracy of the training set was 100.0% in group B. The prediction accuracy of the training set and test set were respectively 95.2% and 78.6% in group C, and the internal cross-validation of the training set was 88.1%. Conclusion Protein chip detection technology can quickly and easily obtain the expression profile of water-soluble proteins of rat liver tissue with a relative molecular weight of 14 000-230 000 at different time points after death. PLS-DA and Fisher discriminant models are established to classify and predict the postmortem interval, in order to provide new ideas and methods for postmortem interval estimation.

Comparison of the two magnetic resonance deartifact techniques in imaging of different porcelain-fused-to-metal crowns / 华西口腔医学杂志

OBJECTIVE@#This study aimed to compare the porcelain-fused-to-metal (PFM) crown artifact in the magnetic resonance imaging (MRI) of the two magnetic resonance deartifact techniques in studying the application value of the propeller-fast spin-echo T2-weighted sequence (FSE T2WI) in troubleshooting PFM crown artifacts.@*METHODS@#A total of 48 patients with right mandible first molar crown who underwent MRI head examination were chosen as subjects in the study. According to different metal substrates, PFM crowns were divided to three types, namely, nickel-chromium alloy crown, cobalt-chromium alloy crown and titanium crown. The patients received two MRI scan sequences, that is, FSE T2WI and propeller-FSE T2WI sequences. The MRI artifacts areas in two sequences were measured.@*RESULTS@#The difference between FSE T2WI and propeller-FSE T2WI sequences in three kinds of PFM crown was significant (P<0.05).@*CONCLUSIONS@#Propeller-FSE T2WI sequence technique can effectively reduce the metal artifacts of various PFM crowns.

Effects of Synthetic Long-Chain Polyphosphate on Blood Coagulation and Platelet Aggregation / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the effects of synthetic long-chain polyphosphate on blood coagulation and platelet aggregation.</p><p><b>METHODS</b>The effect of artificial synthetic long chain poly phosphate on blood coagulation and platelet aggregation was detected by coagulation tests, coagulation factor activity detection and platelet aggregation test, and its mechanism was explored by ELISA, flow cytometry and high content imaging system.</p><p><b>RESULTS</b>The long chain polyphosphates prolonged activated partial thromboplastin time, decreased coagulation factor FⅧ, FⅨ, FⅪ and FⅫ activity, blocked ADP-induced platelet aggregation, and decreased the concentration of calcium and TXA2 in platelet.</p><p><b>CONCLUSION</b>The synthetic long-chain polyphosphate can inhibit endogenous coagulation and inhibit platelet aggregation, which may be related with the inhibition of intracellular calcium and TXA2.</p>

Protective effect of dexrazoxane on cardiotoxicity in breast cancer patients who received anthracycline-containing chemotherapy / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the cardioprotective effects of dexrazoxane (DEX) on breast cancer patients who received anthracycline-containing chemotherapy.</p><p><b>METHODS</b>A total of 122 breast cancer patients after operation were randomly divided into two groups: The experimental group of 61 cases treated with EPI plus DEX (DEX:EPI = 10:1) as adjuvant chemotherapy regimen, and the control group of 61 cases treated with EPI but without DEX. All patients received four cycles of adjuvant chemotherapy and their changes of specific cardiac functional status and hematology status before and after chemotherapy, as well as non-cardiac toxicity were observed and analyzed.</p><p><b>RESULTS</b>Brain natriuretic peptide (BNP) before chemotherapy and after four cycles of chemotherapy in the control group was (106.78 ± 4.52)×10(-6) µg/ml and (187.19 ± 8.71)×10(-6) µg/ml, respectively, with a significant difference between them (P < 0.05). It in the experimental group was (102.34 ± 8.76)×10(-6) µg/ml and (105.29 ± 7.21)×10(-6) µg/ml, respectively, without a significant difference (P > 0.05). Cardiac troponin T (cTnT) before chemotherapy and after four cycles of chemotherapy in the control group was (12.55 ± 2.73)×10(-3) µg/ml and ( 31.05 ± 7.10 )×10(-3) µg/ml, respectively, with a significant difference between them (P < 0.05). It in the experimental group was (12.70 ± 2.15)×10(-3) µg/ml and (13.65 ± 7.82)×10(-3) µg/ml, respectively, without a significant difference (P > 0.05). The hart rate (HR) before chemotherapy and after four cycles of chemotherapy in the control group, was 75.32 ± 7.14 bpm and 89.60 ± 9.21 bpm, respectively, with a significant difference (P < 0.05). It in the experimental group was 78.60 ± 6.29 bpm and 83.10 ± 7.56 bpm, respectively, without a significant difference (P > 0.05). The left ventricular ejection fraction (LVEF) before chemotherapy and after four cycles of chemotherapy in the control group was (65.23 ± 7.82)% and (55.21 ± 7.23)%, respectively, with a significant difference between them (P < 0.05). It in the experimental group was (64.12 ± 6.25)% and (59.6 ± 4.72)%, respectively, without a significant difference (P > 0.05). The absolute neutrophil count before chemotherapy and after four cycles of chemotherapy in the control group was (3.95 ± 1.36)×10(9)/L and (3.50 ± 1.52)×10(9)/L, respectively, without a significant difference (P > 0.05). It in the experimental group, was (4.96 ± 1.41)×10(9)/L and (3.10 ± 1.26)×10(9)/L, respectively, with a significant difference (P < 0.05). The incidence of grade I-IV bone marrow suppression in the experimental group was 21.3%, 16.4%, 24.6%, and 4.9%, respectively. It in the control group was 16.4%, 11.5%, 9.8%, and 5.5%, respectively, with a significant difference (P < 0.05).</p><p><b>CONCLUSIONS</b>Cardiac toxicity after anthracycline treatment in breast cancer patients may be significantly reduced by DEX, without increase of non-cardiac and and non-hematologic toxicity. DEX combined with anthracycline increases the risk of bone marrow suppression, therefore, peripheral blood picture should be monitored or routine bone marrow support may be needed.</p>

Randomized trial of breast self-examination in 266,064 women in Shanghai / 中华肿瘤杂志

<p><b>OBJECTIVE</b>A randomized trial of breast self-examination (BSE) program was carried out to evaluate whether the intensive BSE can reduce the death number of women from breast cancer.</p><p><b>METHODS</b>A total of 266,064 women (age of 30 to 64 years) associated with 519 textile factories in Shanghai had been randomly assigned to a BSE instruction group (132,979 women) or a control group (133,085 women) since 1989. Initial instruction in BSE group included demonstration of proper palpation techniques. It was followed by 2 reinforcement sessions during the subsequent 4 years including video shows, BSE instruction sessions and BSE practice under medical supervision. These activities were continued for 5 years. Attendance at all events was recorded. The cohort was followed through July 2000 for development of breast diseases, and the breast cancer cases were followed up through 2001 for vital status. The data analysis methods used included Kaplan-Meier plots, Log-rank test and Cox modeling.</p><p><b>RESULTS</b>Among women under instruction, 864 breast cancers were detected and 133 breast cancer deaths occurred, and 896 breast cancers were detected and 130 deaths recorded in the control group. The tumor size (P = 0.07), TNM stage (P = 0.39) and cumulative breast cancer mortality rate (P = 0.72) were not significantly different between the 2 groups. However, more and smaller fibroadenomas were detected in the instruction group than in the control group (P < 0.01).</p><p><b>CONCLUSION</b>Intensive instruction in BSE can not reduce mortality rate of breast cancer, but more and smaller benign breast lumps can be detected.</p>