Tiredness is a physiological phenomenon,inevitably appears in certain period of exercise.If the tiredness has not been eliminated promptly,it would roll up to fatigue.It is important to analyze the generation,evaluation and recovery of fatigue,to make people come back to training,working or studying as soon as possible.

BACKGROUND:With the development of modern pathological techniques, the misdiagnosis rate has been reduced remarkably, but special stains are still the most important method for pathological diagnosis. OBJECTIVE:To compare the advantages and disadvantages of different special stains used for observing the structure of human lumbar facet joints. METHODS:The specimens of facet joint cartilage at L4/5 level were collected from patients undergoing lumbar surgery, and then stained with hematoxylin-eosin, safranin O, toluidine blue, Masson, and saranin-O-fast green for structure observation. RESULTS AND CONCLUSION:The structure of the articular cartilage could be observed clearly through hematoxylin-eosin, toluidine blue, and saranin-O-fast green staining. The cartilage surface, tidemark, and subchondral bone were shown by the hematoxylin-eosin staining, with the presence of violet chondrocyte nuclei. Safranin-O-fast green staining showed the four layers of the cartilage clearly, including the shallow layer (cartilage surface), middle layer (spherical cells arranged in disorder), columnar cell layer (large and multinucleated chondrocytes arranged neatly), tidemark, subchondral bone layer; and the cartilage matrix was reddish uniformly, the subchondral bone was green, and the cartilage and bone tissue showed a striking contrast. The cartilage structure was unclear in toluidine blue staining, with clear nuclei and almost no coloring cytoplasm, but the matrix appeared with slight purplish blue. Safranin O staining showed that the cartilage was red, which had no obvious boundary with the cartilage matrix, and chondrocytes were stained lightly. Masson staining showed clear collagen fibers, but the structures of the cartilage and subchondral were obscure. To conclude, safranin-O-fast green staining can achieve the best results, followed by hematoxylin-eosin staining and Masson staining in turn.

Objective To assess the feasibility and the value of MR T2 * mapping in valuing the early degeneration of lumbar intervertebral disc quantificationally.Methods 67 patients with low back pain and 21 healthy volunteers were chosen for the study.The two groups both underwent 3.0T MR with the axial T2 WI and T2 * mapping images in 440 discs of L1-S1.We graded all intervertebral discs by Pfirrmann score,and measured the T2 * values of annulus fibrosus(AF) and nucleus pulposus(NP).Results The T2 * values of the anterior AF and the NP among different Pfirrmann grades were statistically significant (P =0.001;P =0.000,respectively).There was significant difference in T2 * values of the anterior AF at L3/L4 between patients and volunteers (P=0.043);The T2 * values of the NP at L2/L3,L3/L4,L4/L5,L5/S1 between the two groups were significant difference (P＜0.05).There was also distinct difference in T2 * values of the posterior AF at L1/L2 and L4/L5 between the two groups (P＜0.05).Conclusion The lumbar intervertebral disc degenerates from the NP to posterior AF,and mainly occurs at L4/L5.The T2 * mapping technique can provide a good basis for diagnosing in lumbar intervertebral disc degeneration.

AIM: To analyze and screen influencing factors of diabetic patients complicated with retinopathy, and establish and validate prediction model of nomogram.METHODS: A total of 1 252 patients from the Diabetes Complications Early Warning Dataset of the National Population Health Data Archive(PHDA)between January 2013 to January 2021 were selected and randomly divided into a modeling group(n=941)and a validation group(n=311). Univariate analysis, LASSO regression and Logistic regression analysis were used to screen out the influencing factors of diabetic retinopathy, and a nomogram prediction model was established. The receiver operating characteristic curve, Hosmer-Lemeshow test and calibration curve were used to evaluate the model. The clinical benefit was evaluated by the decision curve analysis(DCA).RESULTS: Age, hypertension, nephropathy, systolic blood pressure(SBP), glycated hemoglobin(HbA1c), high-density lipoprotein cholesterol(HDL-C), and blood urea(BU)were the influencing factors of diabetic retinopathy. The area under the curve(AUC)of the modeling group was 0.792(95%CI: 0.763-0.821), and the AUC of the validation group was 0.769(95%CI: 0.716-0.822). The Hosmer-Lemeshow goodness of fit test and calibration curve suggested that the theoretical value of the model was in good agreement(modeling group: χ2=14.520, P=0.069; validation group: χ2=14.400, P=0.072). The DCA results showed that the threshold probabilities range was 0.09-0.89 for modeling group and 0.07-0.84 for the validation group, which suggested the clinical net benefit was higher.CONCLUSION: This study constructed a risk prediction model including age, hypertension, nephropathy, SBP, HbA1c, HDL-C, and BU. The model has a high discrimination and consistency, and can be used to predict the risk of diabetic retinopathy in patients with diabetes.