Enzymatic Digestion Method Coupled with Artificial Intelligence Techniques in Forensic Drowning Diatom Detection / 中山大学学报(医学科学版)

ObjectiveArtificial intelligence （AI） full smear automated diatom detection technology can perform forensic pathology drowning diatom detection more quickly and efficiently than human experts.However， this technique was only used in conjunction with the strong acid digestion method， which has a low extraction rate of diatoms. In this study， we propose to use the more efficient proteinase K tissue digestion method （hereinafter referred to as enzyme digestion method） as a diatom extraction method to investigate the generalization ability and feasibility of this technique in other diatom extraction methods. MethodsLung tissues from 6 drowned cadavers were collected for proteinase K ablation and made into smears， and the smears were digitized using the digital image matrix cutting method and a diatom and background database was established accordingly.The data set was divided into training set， validation set and test set in the ratio of 3：1：1， and the convolutional neural network （CNN） models were trained， internally validated， and externally tested on the basis of ImageNet pre-training. ResultsThe results showed that the accuracy rate of the external test of the best model was 97.65 %， and the area where the model features were extracted was the area where the diatoms were located. The best CNN model in practice had a precision of more than 80 % for diatom detection of drowned corpses. ConclusionIt is shown that the AI automated diatom detection technique based on CNN model and enzymatic digestion method in combination can efficiently identify diatoms and can be used as an auxiliary method for diatom detection in drowning identification.

Optimization of medical educational objectives by improving summative assessment system / 生理学报

Summative assessment plays a decisive role in the educational assessment system, which is a yardstick to measure the cultivating goal of higher education. The rapid progress of modern society has put forward higher standard for higher medical education. Traditional summative assessment system with single dimension that focuses on evaluating the student's learning outcome via a standardized examination cannot meet the higher requirements for undergraduate medical education. We have improved the summative assessment system by optimizing the assessment content, criteria and method, as well as teachers' assessment skills and students' evaluation. The reform greatly increases the teaching quality and learning effect in our university.

Relationship between Postmortem Interval and FTIR Spectroscopy Changes of the Rat Skin / 法医学杂志

Objective To infer postmortem interval （PMI） based on spectral changes of the dorsal skin of rats within 15 days postmortem using Fourier transform infrared （FTIR） spectroscopy. Methods The rats were sacrificed by cervical dislocation after anesthesia, and then placed at 25 ℃ and relative humidity of 50%. The FTIR spectral data collected from the dorsal skin at PMI points were modeled with machine learning technique. Results There was no significant difference of absorption peak location among all the PMI groups but their peak intensities changed as a function of PMIs. The model for PMI estimation was constructed using partial least squares （PLS） regression, reaching a R2 of 0.92 and a root mean square error （RMSE） of 1.30 d. As shown in variable importance for projection （VIP）, four spectral bands including 1 760-1 700 cm-1, 1 660-1 640 cm-1, 1 580-1 540 cm-1 and 1 460-1 420 cm-1 were determined as important contributions to model prediction. Conclusion Application of the FTIR technique to detect postmortem spectral changes of the rat skin provides a novel proposal for PMI estimation.

Expression of NOD2 and NLRP3 in the articular cartilage of a rabbit model of osteoarthritis established by arthrorisis using plaster cast / 中国组织工程研究

BACKGROUND: Nucleotide-binding oligomerization domain (NOD)-like receptor plays an important role against inflammatory responses caused by pathogens and non-pathogens, as well as in the initial stage of autoimmune response. Meanwhile, NOD2 and NOD-like receptor protein 3 (NLRP3) are the representative proteins of NOD-like receptor family. OBJECTIVE: To detect the expression of NOD2 and NLRP3 in a rabbit model of osteoarthritis. METHODS: Thirty New Zealand rabbits were randomly divided into six groups (n=5 per group), including five experimental groups (2, 4, 6, 8 and 10 weeks) and one control group. The model of osteoarthritis was established by fixing the left knee joints using plaster cast, and were sacrificed at postoperative 2, 4, 6, 8 and 10 weeks. The controls received no intervention, and were killed at 10 weeks postoperatively. The left distal femur articular cartilage was taken for safranin-fast green staining. The pathological changes were evaluated by Mankin's scores, and the expression levels of NOD2 and NLRP3 were detected by immunohistochemistry. RESULTS AND CONCLUSION: The Mankin's scores in the experimental groups were significantly higher than those in the control group (P <0.01). Moreover, the scores in the experimental groups were significantly increased with time (P < 0.01). The expression levels of NOD2 and NLRP3 in the chondrocytes were also increased with time (P < 0.01). These results indicate that the expresison of NOD2 and NLRP3 in the cartilage cells is positively correlated with the pathological changes of osteoarthritis, which may be through promoting apoptosis in cartilage cells, thus accelerating the development of osteoarthritis.

Expression of caspase-3 and HAX-1 after cerebral contusion in rat / 法医学杂志

OBJECTIVE@#To observe the expression pattern of caspase-3 and HCLS1-associated protein X-1 (HAX-1) at different time after cerebral contusion in rat, and explore the new method for estimating the injury interval.@*METHODS@#The cerebral contusion model was established using adult SD male rats. Then the rats were randomly allocated into 8 groups: 2 h, 6 h, 12 h, 1 d, 3 d, and 7 d after cerebral contusion, sham-operation and normal control. Expression of caspase-3 and HAX-1 protein after cerebral contusion in rat was detected by Western blotting. Laser scanning confocal microscope was used to observe the number of HAX-1 positive cells and TUNEL-stained cells after cerebral contusion.@*RESULTS@#The expression of caspase-3 increased parallelly with the time after cerebral contusion and reached the peak value on 3 d. The expression of caspase-3 decreased gradually and still maintained a high level expression on 7 d (P < 0.05). The expression of HAX-1 positive cell went up after injury, and reached the peak value at 6 h (P < 0.05), then turned down gradually after 12 h and went out of detection after 3 d. The number of TUNEL-stained cells increased obviously at 2 h and reached the peak value on 3 d. The number of TUNEL-stained apoptotic cells decreased gradually and still maintained a high level expression on 7 d (P < 0.05).@*CONCLUSION@#The expression of caspase-3 and HAX-1 after cerebral contusion has time sequential regularity, which may provide new evidence for forensic diagnosis of cerebral contusion interval.

Cloning, sequence analysis and expression in E. coli of the group 3 allergen of Dermatophagoides farinae / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The dust mites, which are mostly represented by Dermatophagoides spp. (Acari: Pyroglyphidae), are the major sources of indoor allergens. Identification and characterization of these mite allergen molecules are an important step in the development of new effective diagnostic procedures and possible therapeutic strategies for allergic disorders associated with dust mites.</p><p><b>METHODS</b>Total RNA was extracted from Dermatophagoides farinae. The gene coding for Der f 3 was amplified by RT-PCR with the primers designed based on previous sequence published in GenBank. The target gene was cloned intermediately into pMD19-T plasmid and finally into plasmid pET28a (+), expressed in E. coli BL21 at the aid of the inducer isopropyl-D-thiogalactopyranoside (IPTG). The physicochemical properties, spatial structure of the allergen were analyzed with bioinformatics software.</p><p><b>RESULTS</b>The cDNA coding for group 3 allergen of Dermatophagoides farinae from China was cloned and expressed successfully. Sequencing analysis showed that there were nineteen mismatched nucleotides in five Der f 3 cDNA clones in comparison with the reference (GenBank Accession No. AY283291), which resulted in deduced amino acid sequence incompatibility in eleven residues. Bioinformatics analysis revealed that the Der f 3 pro-protein was an extracellular hydrophobic protein, consisting of 259 amino acids with a 16 amino acid signal peptide. The protein was deduced to have three chymotrypsin active sites (53-68 AA, 108-122 AA and 205-217 AA), one N-glycosylation site, one cAMP- and cGMP-dependent protein kinase phosphorylation site, four protein kinase C phosphorylation sites, two casein kinase II phosphorylation sites, and five N-myristoylation sites.</p><p><b>CONCLUSIONS</b>Der f 3 is an extracellular hydrophobic protein which possesses multiple activation and phosphorylation sites. Polymorphism may exist in the Der f 3 gene but this needs to be further confirmed in the future.</p>

Time-order expression of caspase-3 and iNOS in contused human brain tissue / 法医学杂志

OBJECTIVE@#To investigate the expression of caspase-3 and iNOS in different intervals and to provide evidence for estimation of injury intervals after brain contusion in human.@*METHODS@#Thirty cases died of serious brain injury were included into the injury groups and 5 cases died of non-brain injury were served as control group. To analyze the changes of caspase-3 and iNOS expression in brain samples at different intervals (2h, 4-8h, 10-14h, 1-2d, 3-5d, 8-11d) by immunohistochemistry and auto-image analysis system.@*RESULTS@#The level of caspase-3 expression started to increase in 2 hours after brain contusion compared to the control group (P<0.05). The level of caspase-3 expression continued to increase in 1-2 days and maintained high level in 3-5 days compared to the control group (P<0.05), then decreased gradually. There was no statistically significant difference between the expression level of iNOS in 2 hours with the control group (P>0.05). But the expression level of iNOS began to increase in 4-8 hours after brain contusion and reached its maximum in 1-2 days, then decreased. Weak expression of iNOS still could be detected in 8-11 days.@*CONCLUSION@#The expression of caspase-3 and iNOS can be used as effective evidence for human brain contusion interval.