Postoperative corneal topography generation based on attention mechanism and Pix2Pix network / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To explore the use of attention mechanism and Pix2Pix generative adversarial network to predict the postoperative corneal topography of age-related cataract patients undergone femtosecond laser arcuate keratotomy.METHODS:In this retrospective case series study, the 210 preoperative and postoperative corneal topographies from 87 age-related cataract patients(105 eyes)undergoing femtosecond laser arcuate keratotomy at Shanxi Eye Hospital between March 2018 and March 2020 were selected and divided into a training set(180)and a test set(30)for model training and testing. The peak signal-to-noise ratio(PSNR), structural similarity(SSIM)and Alpins astigmatism vector analysis were used to compare the accuracy of postoperative corneal topography prediction under different attention mechanisms.RESULTS:The model based on attention mechanism and Pix2Pix network can predict postoperative corneal topography, among which the model based on Self-Attention mechanism has the best prediction effect, with PSNR and SSIM reaching 16.048 and 0.7661, respectively. There were no statistically significant differences in the difference vector, difference vector axis position, surgically induced astigmatism, and correction index between real and generated corneal topography on the 3mm and 5mm rings(all P>0.05).CONCLUSION:Based on the Self-Attention mechanism and Pix2Pix network, the postoperative corneal topography can be well predicted, which can provide reference for the surgical planning and postoperative effects of ophthalmic clinicians.

Influence factors of debilitating and nutritional risk on complications of primary hip replacement / 中国骨伤

OBJECTIVE@#To analyze relationship of debilitating and nutritional risk on complications of primary hip replacement, and risk factors of influence of complications of primary hip replacement.@*METHODS@#Totally 100 patients who underwent hip replacement from January 2019 to January 2021 were retrospectively analyzed, including 36 males and 64 females, aged from 18 to 85 years old with an average of (73.82±4.04) years old. Postoperative frailty status was evaluated by modified frailty index, and nutritional status was evaluated by clinical biochemical indexes and NRS2002 nutritional risk assessment scale. One hundred patients were divided into frailty group and non-frailty group according to modified frailty index, 100 patients were divided into normal nutrition group and nutritional risk group according to nutritional status, and relationship between frailty, nutritional risk and complications after primary hip replacement was analyzed.@*RESULTS@#There were significant differences in age, body mass index (BMI), complications and ASA grade between frailty group and non-frailty group(P<0.05). There were statistically significant differences in age, BMI, complications and ASA grade between normal nutrition group and nutritional risk group (P<0.05). Thirty-five patients occurred at least one postoperative complications, and the incidence of pulmonary infection was the highest, accounting for 34.29% (12/35). The second was urinary infection, accounting for 22.86%(8/35). Univariate Logistic regression analysis showed that age, BMI, ASA grade, complications, frailty and nutritional risk were the risk factors for postoperative complications. Multivariate Logistic regression analysis showed that complications, frailty and nutritional risk were independent factors affecting postoperative complications.@*CONCLUSION@#Patients with comorbidities, frailty and nutritional risk could increase the incidence of complications. Timely assessment and identification of these patients in time, and formulation of targeted intervention measures have great clinical significance.

Rapid Analysis and Identification of Chemical Constituents from Siwei Tumuxiang San by HPLC-Q-Exactive-MS/MS / 中国实验方剂学杂志

Objective::To rapidly characterize and identify the components of Siwei Tumuxiang San by using high performance liquid chromatography tandem quadrupole-electrostatic field orbitrap high resolution mass spectrometry (HPLC-Q-Exactive-MS/MS). Method::Agilent ZORBAX SB-Aq column (4.6 mm×150 mm, 5 μm) was adopted and 5 mmol·L-1 ammonium acetate+ 0.1% formic acid aqueous solution-acetonitrile were used as mobile phase. According to the separation and structure identification results of chemical components based on the methods of ChemSpider and ChemicalBook database retrieval, a local database of molecular formula, molecular weight, structural formula and MS/MS spectrum information of chemical components in Siwei Tumuxiang San was established. An HPLC-Q-Exactive-MS/MS analysis method was established. The complex compounds of Siwei Tumuxiang San were identified rapidly by using Xcalibar 3.0 software, comparison of reference materials and studies on MS/MS fragment pathways. Result::A total of 110 compounds were identified from the Siwei Tumuxiang San by HPLC-Q-Exactive-MS/MS technology, including 3 sesquiterpene compounds from Inulae Radix, 16 alkaloid compunds and 38 isoprene flavonoid compounds from Sophorae Radix flavescentis, 12 triterpenoid saponin compounds, 1 catechin compounds and 4 flavonoid glycoside compounds from Rubus sachalinensis. The fragment pathways of the main types of compounds were summarized. Among them, mass spectrometry information of 31 compounds was reported for the first time. Conclusion::This study can be used to identify the target compounds and non-target compounds in Siwei Tumuxiang San systematically, accurately and quickly, which will lay a foundation for the in vivo analysis and pharmacokinetic study of the formulation.

Protective effects of endogenous carbon monoxide against myocardial ischemia-reperfusion injury in rats / 生理学报

The present study is aimed to explore the effects of endogenous carbon monoxide on the ischemia-reperfusion in rats. Wistar rats were intraperitoneally injected with protoporphyrin cobalt chloride (CoPP, an endogenous carbon monoxide agonist, 5 mg/kg), zinc protoporphyrin (ZnPP, an endogenous carbon monoxide inhibitor, 5 mg/kg) or saline. Twenty-four hours after injection, the myocardial ischemia-reperfusion model was made by Langendorff isolated cardiac perfusion system, and cardiac function parameters were collected. Myocardial cGMP content was measured by ELISA, and the endogenous carbon monoxide in plasma and myocardial enzymes in perfusate at 10 min after reperfusion were measured by colorimetry. The results showed that before ischemia the cardiac functions of CoPP, ZnPP and control groups were stable, and there were no significant differences. After reperfusion, cardiac functions had significant differences among the three groups (P < 0.05). Compared with pre-ischemia, the cardiac function decreased and obvious cardiac arrest was shown in control and ZnPP groups, while the cardiac function in CoPP group did not change significantly, maintaining a relatively stable level. At the same time, three groups' carbon monoxide level, myocardial enzymology and the cardiac function recovery time after reperfusion also had significant differences (P < 0.05). Compared with those in control group, recovery after reperfusion was faster, activities of creatine kinase and lactic dehydrogenase were significantly decreased, plasma CO and myocardial cGMP contents were significantly increased in CoPP group, while these changes were completely opposite in ZnPP group. It is concluded that endogenous carbon monoxide can maintain cardiac function, shorten the time of cardiac function recovery, and play a protective role in cardiac ischemia-reperfusion.

Advances in ocular biomechanics / 医用生物力学

Ocular biomechanics are generally applied in the diagnosis treatment of high myopia and ocular movement disorder. Progress has also achieved in the development of glaucoma and ocular trauma research fields. In this paper, the advances in the modeling of eye movement, the mechanical properties and mechanobiology of the cornea and sclera, glaucoma biomechanics, and the mechanism of ocular trauma are reviewed.

Effects of mechanical stretch on gene expression of extracellular matrix in rabbit corneal fibroblasts / 医用生物力学

Objective To explore the combined effects of mechanical stretch and interleukin-1β (IL-1β) on gene expression of extracellular matrix in rabbit corneal fibroblasts. Methods Isolated rabbit corneal fibroblasts were subjected to 15% equibiaxial stretch at frequency of 0.1 Hz for 12 h, 24 h and 36 h, respectively, in presence of IL-1β. The gene expressions of matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinases 1 (TIMP-1) and collagen type I alpha 1 (Collagen Iα1) were detected by real-time quantitative PCR. Results The mRNA levels of MMP-1, MMP-3 and MMP-9 could be up-regulated by IL-1β alone. However, MMP-1 and MMP-3 mRNA levels decreased with time, while MMP-9, TIMP-1 and collagen Iα1 increased with time. Compared with corresponding IL-1β treatment with mechanical stretch groups, the mRNA levels of MMP-1, MMP-3 and MMP-9 were increased and the mRNA levels of TIMP-1 and collagen Iα1 were decreased in a time-dependent manner. The mRNA level of Collagen Iα1 was decreased by loading mechanical stretch alone, and would further decrease time-dependently in combination with IL-1β treatment. Conclusions Mechanical stretch combined with IL-1β may facilitate the corneal tissue damage, thereby contribute to the development of keratectasia.

Relationship between corneal thickness and postmortem interval in rabbit / 法医学杂志

OBJECTIVE@#To explore the relationship between corneal thickness and postmortem interval (PMI) in rabbit.@*METHODS@#The rabbit model was established by air embolism. The rabbit cornea was sampled at 6-hour-interval from 0 to 72 h postmortem. After routine HE staining, the whole cornea image was collected by the optical microscope. Three markers were observed including corneal epithelial thickness (x1), corneal stromal thickness (x2) and whole corneal thickness (x3) using Motic Images Plus 2.0 image analysis software and the data were statistically analyzed to establish the regression function with PMI (y).@*RESULTS@#Within 72 h postmortem, rabbit corneal stromal thickness and whole corneal thickness increased at 12h postmortem and reached the peak at 54h postmortem. The two markers showed positive correlation with PMI. The regression functions of the two markers were y = -0.070 2 x2(2) +11.398 x2 + 1634 (R2 = 0.712 2, P < 0.05) and y = -0.074 9 x3(2) +12.036 x3 + 1819.4 (R = 0.675 0, P < 0.05), respectively.@*CONCLUSION@#The two markers of corneal stromal thickness and the whole corneal thickness showed the strong linear correlation with PMI. The correlation of the corneal stromal thickness is better than the whole corneal thickness. The two markers can be used to estimate PMI.

Dan'e fukang soft extract improved the oocyte quality and GDF-9 expressions of endometriosis patients: an experimental study / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To study the mechanism of Dan'e Fukang Soft Extract (DFSE) on improving oocyte and embryo qualities in endometriosis patients undergoing in vitro fertilization-embryo transfer (IVF-ET).</p><p><b>METHODS</b>Totally 70 patients with endometriosis confirmed by laparoscope were randomly assigned to two groups, the treated group and the control group, 35 cases in each group. Patients in the treated group were treated with DFSE + controlled ovarian hyperstimulation (COH), while those in the control group were treated with DFSE placebo + COH. Besides, recruited were another 35 subjects undergoing intracytoplasmic sperm injection-embryo transfer (ICSI-ET) as a normal control group. The content of growth differentiation factor 9 (GDF-9) in the granulocytes of the mature follicular fluid on the oocyte retrieval day was determined by Western blot. The mRNA expression of GDF-9 was detected by RT-PCR. The oocyte retrieval number, the cleavage rate, the fertilization rate,the high-quality embryo rate, and the pregnancy rate were compared.</p><p><b>RESULTS</b>The mRNA expression of GDF-9 in the granulocytes was significantly higher in the treated group than in the control group, showing statistical difference (P < 0.05), but with no statistical difference when compared with that of the normal control group. There was no statistical difference in the cleavage rate between the two groups (P > 0.05). The fertilization rate and the high-quality embryo rate were higher in the treated group than in the control group, showing statistical difference (P < 0.05), but with no statistical difference when compared with that of the normal control group.</p><p><b>CONCLUSIONS</b>DFSE could improve the oocyte and embryo qualities of endometriosis patients undergoing IVF-ET. Its mechanism might be associated with regulating the GDF-9 mRNA level of granulocytes.</p>

Effects of mechanical stimulation on basic fibroblast growth factor expression of corneal fibroblasts / 医用生物力学

Objective To investigate the effect of different mechanical environment ( in vivo and in vitro) on expression of basic fibroblast growth factor (bFGF) and explore the role of mechanical stimulation in corneal tissue repair after laser assisted in situ keratomileusis (LASIK) surgery. Methods Animal models by LASIK surgery were established to keep the corneas under different mechanical environment. The experimental animals were killed at the first week or the first month after LASIK surgery to obtain the corneas. In addition, the primary corneal fibroblasts were subjected to cyclic mechanical stretch (0.1 Hz; 5%, 10%, 15% stretch; 6 h or 24 h) using Flexcell 4 000 tension system. Expression of bFGF was determined by ELISA method. Results At the first week after LASIK surgery, expression of bFGF was increased significantly in 30% group (residual stroma bed accounting for 30% of the whole cornea), as compared with the control group (P<0.05), and then it was decreased to the normal level in all groups at the first month after LASIK surgery. Analysis on the same surgery method at different time showed that there were significant differences only in 30% group at the first week and month (P<0.05). Cyclic stretch experiment in vitro indicated that bFGF expression in 15% stretch group was significantly increased after 6 h than that in the control group (P<0.05), with a significant decrease after 24 h (P<0.05). Conclusions Mechanical stimulation can regulate bFGF expression of corneal tissues and corneal frbroblasts, and bFGF plays a positive role in the early corneal tissue repair after LASIK surgery.

Application of particle tracking microrheology in biomechanics / 医用生物力学

As a new technique of determining the viscoelasticity of soft biomaterials and cell cytoplasm in living cells, particle tracking microrheology (PTM) is mainly applied in the biomechanical research field, such as cell movement, embryo development, laminopathies. PTM has many advantages over the conventional detection methods in cell mechanics. Using this technique, the Brownian motion of probe particles embedded in the medium could be measured by the video-microscopy, and the movement trajectories of the probe could be mathematically transformed into the mean squared displacements (MSDs) thus to extract the parameters such as the frequency-dependent viscoelastic modulus or the creep compliance from the time dependent MSDs of the probes. The basic principles of PTM technique and its application in biomechanics will be reviewed in this paper.

DNA degradation in nucleolus of skeletal muscle, heart, liver, kidney and brain in mice after death / 法医学杂志

OBJECTIVE@#To study the change of DNA degradation in nucleolus of mice organs and its relationship with the postmortem interval, and to investigate a new accurate method to estimate the postmortem interval.@*METHODS@#Eight parameters of cell nuclei were chosen, including the head DNA level, the tail DNA level, the head radius, the tail length, the tail moment, the Olive moment, the head area and the tail area. The changes of DNA degradation were analyzed in skeletal muscle, myocardium, liver, kidney and brain in mice at different intervals (0-72 h postmortem) by using single-cell gel electrophoresis and fluorescent microscope connected with auto-analysis-image system.@*RESULTS@#The tail DNA level, the tail length, the tail moment, the Olive moment and the tail area showed an increasing tendency. The head DNA level, the head radius and the head area showed a decreasing tendency within 72h postmortem in mice. A quadratic regression equation (P < 0.001) and multiple regression equation of DNA degradation tendency were established (P < 0.000 1).@*CONCLUSION@#The regression equations established can be used as a new method for estimating postmortem interval in forensic practice.

Advances in biomechanical study of sclera and scleral fibroblasts / 医用生物力学

Sclera plays an very important role in maintenance of eyeball structure and its functions. The biological and biomechanical properties of sclera is determined by the extra cellular matrix metabolism, the cytokine expression and its own biomechanical properties of scleral fibroblasts. Lots of biological and biomechanical changes in sclera and scleral fibroblasts are the concomitants in the process of myopic development and therapy. The biomechanical studies on sclera and scleral fibroblasts by Mechanics Biology coupling will enable to reveal the physiological function, pathological change and therapeutic mechanism of ocular organ and in this review, such biomechanical studies about sclera and scleral fibroblasts were summarized and discussed.

Mechanical effect of Myosin Ⅱ on cell mitosis / 医用生物力学

Cytoskeleton can cause active deformations and resist passive deformations which related to some active deformations of cells known as mitosis. Mitosis occurs through a series of stereotypical shape changes resulted in the mechanical separation of a mother cell into two daugther cells, accompanied by mechanical phenomena throughout the whole course. As a molecular motor of cytoskeleton, myosin II is a kind of multifunctional protein that can participate in mitosis. To make deep study on the roles of myosin II in mitosis could get important theoretical and application value. This paper will sum up the recent research achievements on roles of myosin II in mitosis.

Effect of inhibiting cytoskeleton on the mechanical properties of normal rat kidney cells / 医用生物力学

Objective To determine whether the alteration of cytoskeleton interfere with the mechanical properties of normal rat kidney cells (NRKCs).Method NRKCs were treated with cytochalasin D, colchicine and blebbistatin using micropipette aspiration technique, and the changes in Young’s modulus and viscoelasticity of NRKCs were assessed. Results The Young's modulus of is significantly decreased after treated with all cytoskeleton inhibitors. Compared to the control, the viscoelasticity is significantly decreased in NRKCs treated with cytochalasin D and blebbistatin, but in not in colchicines treated cells. Conclusions The effect of blebbistatin on NRKCs mechanical properties is independent of cytoskeleton. Inhibition of assembling of actin meshwork or the activity of myosin II ATPase will reduce cell's Young's modulus and viscoelasticity. In addition, microtubule assembling is correlated with Young's modulus rather than viscoelasticity.

Effects of post material on stress distribution in dentine / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate stress distribution of different material restored post-cores in dentine and provide a theoretical guidance for clinical use.</p><p><b>METHODS</b>A three-dimensional finite element model of maxillary central incisor restored with post-core and PFM crown was constructed by SCT scan technology. Based on this model, stress distribution in dentine was analyzed before and after post-core restorations with 6 different materials, including cast Ni-Cr alloy, cast titanium alloy, cast gold alloy, glass fiber reinforced composite, polythene fiber reinforced composite, and common composite resin.</p><p><b>RESULTS</b>When the tooth was restored with cast Ni-Cr alloy post and PFM crown, the maximum tensile stress and Von Mises stress in dentin at post apex increased 152% and 162% respectively, compared with a tooth restored only with PFM crown. If polythene fiber reinforced composite was used as post material, the stress distribution did not significantly change. When the other materials were used for the post, the stress distribution changed greatly. The elastic modulus of post-core materials affected the stress distribution pattern in dentine.</p><p><b>CONCLUSION</b>The materials with elastic modulus similar to that of dentin, such as polythene fiber reinforced composite, may be suitable for post restoration.</p>