Objective To investigate whether the agonist of delta opoid receptor D-Ala(2),D-Leu(5) enkephalin (DADLE) has the effect of decreasing myocardial injury during ischemia-reperfusion of adult rabbits’ myocardium，so that a new mehanism and way to myocardial protection could be found. Methods Langendorff model was used during the experiment. Thirty rabbits were divided into three groups randomly (each group 10 rabbits). Control group: St.Thomas Ⅱ cardioplegic solution was used; group 1: St.Thomas Ⅱ cardioplegic solution and DADLE (1mg/kg) were used; group 2: St.Thomas Ⅱ cardioplegic solution and naloxone(3mg/kg) were used to induce the hearts to arrest respectively. After arrest the hearts were reperfused respectively. Data of left ventricle development pressure(LVDP) was recorded before and after ischemia. Biochemical indicators of myocardium, lactate dehydrogenase(LDH) were detected before and after ischemia. Some myocardial tissues were used to explore the changes of the tissue of ultrastructure with electron microscope，when the experiment was over. Still some myocardial tissues were to be detected by flow cytometer to evaluate the apoptosis of the myocardium. Results The LDH and LVDP showed significant difference among three groups after ischemia(Plt;0.05); LVDP in group 1 was higher than those in group 2 and control group(69.8±5.8 mmHg vs. 23.4±3.9 mmHg; 69.8±5.8 mmHg vs. 37.9±4.7 mmHg; Plt;0.05), the LDH in group 1 was lower than those in group 2 and control group(1 272.6±59.1 U/L vs. 2 764.4±27.7 U/L, 1 272.6±59.1 U/L vs. 1 884.4±37.5 U/L; Plt;0.05). The apoptosis rate in group 1 was lower than those in group 2 and control group. As could be shown from the ultrastructure: mitochondria structure was nearly normal in group 1; mitochondria structure was injuried severely in group 2; there was a minor injury in control group. Conclusion Agonist of δ opoid receptor DADLE in cardioplegic solution could induce hibernation, which has myocardial protection effect during ischemia-reperfusion injury.
A simple model of canine auto-trasplantation of liver was set up by ourselves, and the effects of hepatic artery ischemia (HAI) on ultrastructure of liver and biliary duct transplanted were observed. The results showed that the liver and biliary cells swelled slightly, mitochondrial matrix was loose and ridges were vague just often perfusion. Afte HAI for 3 hours the edema of hepatic and biliary cells aggravated cytoplasm was loose, mitochondria enlarged and partly vacuolar degenerated, ridges broke or disappeared, flocculent focal densites was seen in the matrix, endoplasmic retculum distended obviously, and the ribosome depolymerizated. So we consider that HAI causes obvious damage to hepatic and biliary cells. These indicate that HAI is one of the important factors of complication after liver transplantation, especially some biliary complications.
Objective To investingate the ultrastructural changes of retinal pigment epithelium(RPE) and its permeability in spontaneously hypertensive rats(SHR)and explore the relation between these changes and hypertensive retinopathy.MethodsThe ultrastructure of RPE cells in the SHR aged five,six,seven months wasobserved with transmission electronmicroscope and compared to its normotensive control strain(WKY) with the same age.Then,lanthanum tracer procedures were carried out to investigate pathological changes of the blood-retinal barrier.Results (1)In SHR the main pathological changes involved swelling of mitochondria,enlargement of endoplasmic reticula,decrease of RPE cell infolding,and sparseness of microvilli.These degenerations were more serious in older rats with higher blood pressure.(2)The breakdown of outer blood-retinal barrier with permeation of lanthanum tracers were evident in SHR aged six or seven month,however,in WKY and five-month SHR the traces were prevented from passing by tight junctions.ConclusionThe degeneration of RPE owing to ischemia and anoxia arises in early periosd of hypertensive retinopathy.The pathological changes of ultrastructure and permeability might interact with the damage of visual cells and play a main role in the hypertensive retinopathy.
ObjectiveTo investigate the effects of acute and chronic ozone exposure on inflammation,structure and function in murine lung. Methods32 C57/BL6 mice were randomly divided into a single (acute) ozone exposed group,a single air exposed group,a multiple (chronic) ozone exposed group (every three days over 6 weeks),and a multiple air exposed group with 8 mice in each group.The mice were exposed to 2.5 ppm of ozone or air for 3 hours per time and sacrificed 24 hours after the last time of ozone exposure.Lung volume,low attenuation area (LAA) percentage,lung function,cell counts and malondialdehyde (MDA) in bronchoalveolar lavage fluid (BALF),8-hydroxy-2'-deoxyguanosine (8-OHdG) in serum,inflammation scores and mean linear intercept (Lm) in lung section were assessed. ResultsCompared with the single air exposed group,single (acute) ozone exposure led to increases in inflammatory cells in BALF,inflammation scores in the lung tissue,MDA in BALF and 8-OHdG in serum,but had no effect on lung volume,LAA percentage,airflow or Lm.Compared with the single (acute) ozone exposed group,the single air exposed group and the multiple air exposed group,multiple (chronic) ozone exposure increased inflammatory cells in BALF,lung volume,LAA percentage,total lung capacity and lung compliance,mediated airflow obstruction,and also increased lung inflammation socres and Lm. ConclusionAcute ozone exposure induced airway/lung inflammation and oxidative stress,while chronic ozone exposure induced airway/lung inflammation,emphysema and airflow obstruction.
ObjectiveTo investigate relationship between ultrastructural changes and expression of basic fibroblast growth factor of diabetic retinopathy in rats.MethodsDiabetes was induced in rats with a single injection of streptozotocin (STZ) and divided into normal control group and 1- , 3- and 5- month diabetes group. The paraffin slide was observed by in-situ hybridization and immunohistochemistry, and retinal ultrastructure was examined by transmission electron microscopy.ResultsNo change of retinal ultrastructure was found in the control group. Different degrees of ultrastructure lesion were found in 1-month diabetic rats with fragmental increase of thickness of basement membrane, swelling of endothelial cells and obvions fingerlike processes in the capillary cavity, disconcentration of heterochromatin both in endothelium and pericyte, and swelling and degeneration of mitochondrion. The edema of endothelial cells of 3-month diabetic rats was more serious than that of 1month ones, and the capillary cavity was nearly occluded. In 5-month diabetic rats, the basement membrane was unevenly thickened, or obviously split. The positive rate of in-situ hybridization in 3-month diabetic rats was 77.8% while the positive rate of immunohistochemical stain was 55.6%, which increased to 88.9% in 5-month diabetic rats.ConclusionsThe occurrence of the ultrastructural changes in STZ rats with diabetic retinopathy is earlier than that of the expression of bFGF.(Chin J Ocul Fundus Dis, 2003,19:348-351)
OBJECTIVE To investigate possibility of cartilage cultured in centrifuge tube as graft materials. METHODS: Articular chondrocytes isolated from a 3-week-old rabbit formed cartilage after cultivation for 2 weeks. Articular cartilage of humeral head, growth plate of proximal tibia and meniscus were collected from a 6-week-old rabbit. The ultrastructure of chondrocytes and extracellular matrix in the three kinds of cartilages and cultured cartilage were observed by transmission electronic microscopy. RESULTS: Cartilage cultured in centrifuge tube possessed unique ultrastructure and was similar to articular cartilage and growth plate, but it was markedly different from meniscus. The four kinds of cartilages were characteristic of respectively different chondrocytes and extracellular matrix. Cultured cartilage showed typical apoptosis of chondrocytes and "dark chondrocytes" appeared in growth plate. Condrocyte apoptosis was not seen in articular cartilage and meniscus. CONCLUSION: Cartilage cultured in centrifuge tube has unique ultrastructure and may be used as graft materials for articular cartilage and growth plate.
In order to study the influence of severity of tendon injury on the morphology of collagen fibers during healing process of extensor tendons, 40 female Wistal rats were used for investigation. The rats were divided into 2 groups. Transection of the tendon of extensor digitorum longus was performed in one group, while partial section of the same tendon was performed in the other group. Morphometric analysis was undertaken on the 15th, 30th, 60th and 90th day after operation. The result was that there was no significant difference between the two groups both in distribution and diameter of collagen fibers on the 15th and 30th days (P gt; 0.05). However, there was significent difference between those on the 60th and 90th days (P lt; 0.05). It was concluded that the severity of the tendon injury could influence the morphology of collagen fibers during the late stage of tendon healing.
Objective：To observe the histochemical changes of retinal photochemical damage in rats. Methods：The changes of retinal ultrastructure were observed.The concentration of malondaldehyde(MDA) was tested and the activity the histochemical change of cytochrome oxidase (CCO) and (Mg ++ -ATPasw) were evaluated on the retnal photochemical damage in SD rats. Results：At the 6th hour after light exposure,the swelling appwared at the nuclei of photoreceptor,the mitochondria of inner segment.The apical microvilli of RPE disappeared and lysosomes increased in RPE.On the 6th day after light exposure,the changes became more obvious.While on the 14th day after light expose the nuclei of photoreceptors and the inner segments renewed but the arrangement of the disk was lose;and the microvilli appeared of the disk was lose;and the microvilli appeared at the tip of RPE.The Activity of CCO and Mg ++ -ATPase decreased and MDA increased in retina at the 6th hour and on the 6th day and they recovered on the 14th day after light exposure. Conclusion：Lipd peroxidation that broke the cell membrane system of photoreceptor which induced changes of the cell ultrastru cture abd the activity of enzyme might relate to pathogenesis in retinal photochemical damage. (Chin J Ocul Fundus Dis,1998,14:38-40)
Polypoidal choroidal vasculopathy (PCV) is originally defined as a separate disease, but with the development of imaging techniques, it has now been included in the spectrum of neovascularization. In the Asian population, the prevalence of PCV is high, and with the deepening of clinical studies, the pathological characteristics, pathogenesis and clinical manifestations of PCV have been more deeply understood. Through dynamic observation and histopathological study of PCV lesions during operation, it can be confirmed that the lesions are mainly located between the retinal pigment epithelium and the Bruch membrane, rather than originating from the choroidal circulation, which is of great significance for understanding the origin and natural course of PCV. It is worth noting that although a theoretical bridge has been established between age-related macular degeneration (AMD)/PCV, there is a lack of intuitive clinical data on the ultrastructural and molecular manifestations of the cells/stroma in the local lesions of the eye, especially the progression of AMD/PCV from early/middle stage to exudative stage. It is precisely because of this that highly attractive research topics and exploration space are proposed for the future.
Objective To automatically segment diabetic retinal exudation features from deep learning color fundus images. Methods An applied study. The method of this study is based on the U-shaped network model of the Indian Diabetic Retinopathy Image Dataset (IDRID) dataset, introduces deep residual convolution into the encoding and decoding stages, which can effectively extract seepage depth features, solve overfitting and feature interference problems, and improve the model's feature expression ability and lightweight performance. In addition, by introducing an improved context extraction module, the model can capture a wider range of feature information, enhance the perception ability of retinal lesions, and perform excellently in capturing small details and blurred edges. Finally, the introduction of convolutional triple attention mechanism allows the model to automatically learn feature weights, focus on important features, and extract useful information from multiple scales. Accuracy, recall, Dice coefficient, accuracy and sensitivity were used to evaluate the ability of the model to detect and segment the automatic retinal exudation features of diabetic patients in color fundus images. Results After applying this method, the accuracy, recall, dice coefficient, accuracy and sensitivity of the improved model on the IDRID dataset reached 81.56%, 99.54%, 69.32%, 65.36% and 78.33%, respectively. Compared with the original model, the accuracy and Dice index of the improved model are increased by 2.35% , 3.35% respectively. Conclusion The segmentation method based on U-shaped network can automatically detect and segment the retinal exudation features of fundus images of diabetic patients, which is of great significance for assisting doctors to diagnose diseases more accurately.