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Objective:To investigate the effects of riboflavin-ultraviolet A scleral collagen cross-linking on the retina under different irradiation time, and to determine the safe irradiation time.Methods:Sixty healthy New Zealand white rabbits were randomly divided into control group (0 minute group), 10 minutes group, 20 minutes group, 30 minutes group and 40 minutes irradiation group according to the irradiation time, with 12 rabbits in each group.The left eye was irradiated with riboflavin-ultraviolet A scleral collagen (370 nm, 10 mW/cm 2). The histopathological change of retina was observed by light microscope and transmission electron microscope and compared among different groups.The concentration of MDA and the activities of SOD, CAT and GSH-Px in retinal tissue were detected by corresponding kits.The expression levels of SOD and CAT proteins in retinal tissue were detected by Western blot method.The study protocol was approved by the Binzhou Medical University Laboratory Animal Ethical Committee (No.2017-80). The use and care of animals complied with the statement of ARVO and the Regulation on the Management of Laboratory Animal Quality of China. Results:Under the light microscope, the structure of the retinas in the control group was orderly arranged.Under the transmission electron microscope, the lamellar structure in the inner segment and the mitochondrial structure in the outer segment of the photoreceptor cells were intact, and the mitochondrial ridge was continuous in the control group.There was no obvious difference in retinal morphology between the 10 minutes irradiation group and the control group under both the light microscope and the transmission electron microscope, and the retinal damage became more severe with the prolongation of irradiation time.The concentration of MDA in the retina of each group was elevated gradually with the increase of irradiation time, and the difference was statistically significant ( F=65.25, P<0.05). The concentration of MDA was (11.31±1.84), (14.94±1.04)and (18.25±1.42)nmol/mgprot in the 20 minutes, 30 minutes and 40 minutes irradiation groups respectively, which were significantly higher than (1.13±0.02)nmol/mgprot in the control group (all at P<0.05). The MDA concentration in 20 minutes, 30 minutes and 40 minutes irradiation groups was increased successively, showing statistically significant differences (all at P<0.05). With the prolongation of irradiation time, the activities of SOD, CAT and GSH-Px as well as the expression levels of SOD and CAT proteins were significantly decreased gradually ( F=44.09, 34.18, 35.60, 115.75, 78.86; all at P<0.05). The differences between the control group and 20 minutes, 30 minutes, 40 minutes irradiation groups, and the differences among 20 minutes, 30 minutes, 40 minutes irradiation groups were statistically significant (all at P<0.05). Conclusions:Riboflavin-ultraviolet A 10 mW/cm 2 scleral collagen cross-linking irradiation for 10 minutes is safe.Excessive irradiation time can cause damage to the retina of rabits.
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Background It is determined that riboflavin/ultraviolet A (UVA)-induced corneal collagen crosslinking is able to increase resistance of cornea against enzymatic digestion and has antimicrobial efficacy for various kinds of bacteria in vitro.However,its in vivo study is less now.Objective This study aimed to evaluate the efficacy of iontophoresis-mediated corneal collagen crosslinking combined with or without drugs for Staphylococcus aureus keratitis.Methods Bacterial keratitis models were induced by the interstromaly injection of Staphylococcus aureus suspension with concentration 2× 109/ml in the right eyes of 40 rabbits,and then the rabbits were randomly classified into the model group,gatifloxacin eye drops group,riboflavin/UVA corneal crosslinking group and drugs+ crosslinking group.The smearing of corneal surface was performed for the identification of bacteria 24 hours after injection.Iontophoresis-mediated riboflavin/UVA crosslinking was applied on the eyes of the riboflavin/UVA corneal crosslinking group and drugs+crosslinking group,and gatifloxacin eye drops was topically used 7 times per day on the eyes of the gatifloxacin eye drops group and drugs+crosslinking group.The corneal inflammation was examined and graded under the slit lamp biomicroscope before and after treatment.Ocular anterior segment optical coherence tomography(AS-OCT),corneal histopathology and ultrastructure were examined 14 days after treatment.The living environment of the experimental animals was maintained at 21 ℃ with a 12-hour light and dark cycle.Animals used in this study were treated in accordance with the Weifang Medical College Animal Experimentation Ethic Committee (AEEC) guidelines.The study protocol was approved by the AEEC.Results Corneal inflammation and ulcer were observed,but no significant difference was found in the inflammatory grade among the 4 groups 24 hours after injection (x2=0.293,P＞0.05).In the 14th day after injection,the corneal ulcer area was smaller and corneal edema was milder in the drugs+crosslinking group compared with the model group,gatifloxacin eye drops group and riboflavin/ UVA corneal crosslinking group,showing a significant difference in the inflammatory grade among them (x2 =38.710,P＜0.001).The cornea thickness values of ulcer zone were (428.1 ± 146.2) μm on the 14th postinjected day in the drugs+crosslinking group,which was evidently higher than those in the model group,gatifloxacin eye drops group and riboflavin/UVA corneal crosslinking group,with a significant difference among the 4 groups (F =8.310,P＜0.001).A lower degree of destruction of cornea collagen and less inflammatory cells were seen in the cornea tissue of the drugs+ crosslinking group by haematoxylin and eosin staining in comparison with other 3 groups,and normal keratocytes were much more in the drugs + crosslinking group than those in other treated groups.Conclusions Iontophoresismediated corneal collagen crosslinking can alleviate Staphylococcus aureus keratitis.The combination of crosslinking with drugs has a better effectiveness than the administration of gatifloxacin eye drops only or riboflavin/UVA corneal crosslinking only.
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Objective To investigate the features,prevention and treatment of complications of ultrasound-guided hepatic puncture biopsy.Methods One hundred and seventy-five cases underwent ultrasound-guided hepatic puncture biopsy were retrospectively analyzed.Results The incidence of complications was 16 cases (9.1%),including 5 cases with vasovagal episodes(2.9%),4 cases with ache which needed medicine treatment (2.2%),3 cases with hemorrhage in liver capsule(1.7%),3 cases with hypoglycemia(1.7%),1 case with serve hemorrhage in abdominal cavity(0.6%).Hemorrhage limited in liver capsule,vasovagal episodes,hypoglycemia and ache were relieved with corresponding treatments.One case with hemorrhage in abdominal cavity was handled with percutaneous microwave ablation therapy guided by contrast-enhanced ultrasound.Conclusions Ultrasound-guided hepatic puncture biopsy has good value and low complication.The most severe complication is hemorrhage,which can be handled with percutaneous microwave ablation therapy guided by contrast-enhanced ultrasound.
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Objective To quantitatively study the features of cerebromspinal fluid(CSF)flow dynamies in normal sella region in MRI with phase-contrast method.Methods Seventeen healthy volunteers were studied.The CSF flow image in sella region was positioned at the middle sagittal T1WI or T2WI image.This pulse sequence used a encoding velocity of 20 cm/s.The waveforms were analyzed for the maximum flow velocity,flow volume rate and the change of the figures.From the velocity and area measurements on the cine images,mean CSF flow was calculated in millimeters per second and milliliters per cardiac cycle.Results The normal CSF flow of the sella region had two directions which was downward(caudal)flow during thesystolic period and upward(cranial)flow during the diastolic period of the cardiac cycle.The downward and upward peak flow velocity,mean downward and upward flow velocity and mean flow velocity was(1.44±0.99)cm/s,(302.71±248.15)ms,(1.16±0.64)cm/s,(331.00±225.38)ms,(0.49±0.39)cm/s.(0.67±0.44)cm/s,(0.54±O.30)cm/s,respectively.The downward and upward peak flow volume rate.mean downward and upward flow volume rate and mean flow volume rate was (0.014±0.009)ml/s.(0.012±0.006)ml/s,(0.047±0.041)ml/s,(0.053±0.003)ml/s,(0.005±0.003)ml/s,(0.034±0.031)ml/s,respectively.The mean cycle was(775.25±173.06)ms.Conclusion Phase-contrast method in MRI cine is a noninvasive method to study the CSF flow in physiological and pathological conditions for determining the pattern,direction,speed and quantity of the CSF flow.Therefore it is better than other invasive research modalities and has an important value in clinical application.