We studied the influence of electrode array parameters on temperature distribution to the retina during the use of retinal prosthesis in order to avoid thermal damage to retina caused by long-term electrical stimulation. Based on real epiretinal prosthesis, a three-dimensional model of electrical stimulation for retina with 4 X 4 microelectrode array had been established using the finite element software (COMSOL Multiphysics). The steady-state temperature field of electrical stimulation of the retina was calculated, and the effects of the electrode parameters such as the distance between the electrode contacts, the materials and area of the electrode contact on temperature field were considered. The maximum increase in the retina steady temperature was about 0. 004 degrees C with practical stimulation current. When the distance between the electrode contacts was changed from 130 microm to 520 microm, the temperature was reduced by about 0.006 microC. When the contact radius was doubled from 130 microm to 260 microm, the temperature decrease was about 0.005 degrees C. It was shown that there were little temperature changes in the retina with a 4 x 4 epiretinal microelectrode array, reflecting the safety of electrical stimulation. It was also shown that the maximum temperature in the retina decreased with increasing the distance between the electrode contacts, as well as increasing the area of electrode contact. However, the change of the maximum temperature was very small when the distance became larger than the diameter of electrode contact. There was no significant difference in the effects of temperature increase among the different electrode materials. Rational selection of the distance between the electrode contacts and their area in electrode design can reduce the temperature rise induced by electrical stimulation.
Electric Stimulation ; Finite Element Analysis ; Microelectrodes ; Models, Theoretical ; Retina ; physiology ; Software ; Temperature ; Visual Prosthesis

Obstructive sleep apnea (OSA)is a high incidence of potentially dangerous disease,characterized by intermittent hypoxia or hypercapnia.It is an independent risk factor for ischemic stroke.Currently a number of studies have confirmed OSA closely associated with oxidative stress.In this paper,the complex mechanisms of oxidative stress in the OSA and the occurrence of stroke will be reviewed,such as promoting atherosclerosis,damaging the mitochondria,ischemia -reperfusion injury,ischemic preconditioning.To investigate the relationship between OSA,oxidative stress and stroke from molecular mechanisms.

Objective To explore the surgical effects and follow-up results in treating adult aortic coarctation patients using ascending aorta-abdominal aorta vascular prosthesis bypass and summarize the clinical experiences. Methods From May 2008 to July 2009, ascending aorta-abdominal aorta vascular prosthesis bypass surgery was performed in nine patients with adult aortic coarctation, among which, four were male, and five were female, with the average age of 42.6 years old. All patients had upper extremity hypertension, the systolic blood pressure difference between their upper extremities and lower extremities was 55 - 100 mm Hg, mean (70.2 ± 15. 6) mm Hg. Among which, seven cases showed descending aorta aneurysmal dilatation at coarctation segment distal end, with the wall thinning; two cases showed long segment stenosis; three cases showed aortic wall near coarctation segment was calcified. All cases belonged to complex aortic coarctation. All patients underwent radial artery and dorsalis pedis artery puncture manometry, the surgical effects were evaluated according to mean pressure difference changes between radial artery and dorsalis pedis artery before and after operations. Results All patients were cured and dispertension has been significantly improved, before operation, the mean pressure difference between radial artery and dorsalis pedis artery was 36 - 63 mm Hg, mean [(48.2 ± 5.6 ) mm Hg]; 24 hours after operation, the mean pressure difference between radial artery and dorsalis pedis artery was 0 - 13 mm Hg, mean [(6.2 ± 1.6) mm Hg], significantly reduced ( P ＜per extremity hypertension disappeared, no need for oral antihypertensive drugs, the mean pressure differences between upper extremities and lower extremities after operations were all less than 20 mm Hg, thoracoabodominal aorta main vessels multi-slice CT examination three months after operation showed that bypass vascular prosthesis was unobetructed, two cases showed that autologous artery at aortic coarctation distal end were partly occluded. Conclusion Ascending aorta-abdominal aorta vascular prosthesis bypass would be an effective means for the treatment of adult aortic coarctation patients.

Objective To investigate the correlation between cerebral microbleeds (CMBs ) and cognitive impairment in patients with chronic cerebral ischemia. Methods From January 2015 to January 2017, patients with chronic cerebral ischemia admitted to the Department of Neurology, the Second Hospital of Hebei Medical University were divided into CMBs positive group and CMBs negative group according to the findings of susceptibility weighted imaging. Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were used to compare the cognitive function of both groups of patients and analyze the effects of different parts of CMBs on cognitive function. They were divided into cognitive impairment group and non-cognitive impairment group according to MoCA scores. Multivariate logistic regression analysis was used to determine the independent risk factors for cognitive impairment. Results A total of 96 patients were enrolled, aged 45-83 years, 32 were females (33. 3％) and 64 were males (66. 7％). There were 51 patients (53. 1％) in the CMBs positive group, and 45 (46. 9％) in the CMBs negative group, there were 33 patients (34. 4％) in the cognitive impairment group and 63 (65. 6％) in the non-cognitive impairment group. In the CMBs positive group, 10 patients had lobar CMBs, 29 had deep brain and infratentorial CMBs, and 12 had mixed CMBs. Multivariate logistic regression analysis showed that age (odds ratio [OR] 1. 115, 95％ confidence interval [CI] 1. 030-1. 207; P = 0. 007), the number of CMBs (OR 1. 254, 95％ CI 1. 064-1. 479; P = 0. 007), Fazekas scale score (OR 2. 697, 95％ CI 1. 012-7. 185; P = 0. 047), and multiple lacunar infarction ( OR 7. 103, 95％ CI 1. 248- 40. 424; P = 0. 027 ) were the independent risk factors for cognitive impairment. Compared with the CMBs negative group, the rates of cognitive impairment and dementia in the CMBs positive group were higher. The total MoCA score, visual space and execution function, attention, and delayed recall scores were significantly lower (all P < 0. 05). Each cognitive domain score in the lobar CMBs group were significantly lower than that in the non-lobar CMBs group (all P < 0. 05). There was no significant difference in each cognitive domain score between deep and infratentorial CMBs group and that of the non-deep and infratentorial CMBs group (all P > 0. 05). The visual space and execution function, attention, and delayed recall in the mixed CMBs group were significantly lower than those in the non-mixed CMBs group (all P < 0. 05). Conclusion CMBs (especially lobar CMBs) may cause a decline in overall cognitive function, even dementia in patients with chronic cerebral ischemia, and they are most closely related to visual space and executive function, attention, and delayed recall.

Objective To establish a model for preparation of tissue-engineered skin grafts with hTERT cells carrying human papillomavirus type 6 (HPV 6) genome in vitro, so as to lay a foundation for studying HPV life cycle. Methods The full-length linear HPV6 genome and plasmid pEGFP-▲EGFP were electrophoretically cotransferred into hTERT cells. After selection using G418 resistance, Southern blotting was performed to determine the viral load of HPV6 in transfected cells. 3T3 J2 trophoblastic cells, type I rat-tail collagen and hTERT cells containing the full-length HPV6 genes (HPV6.hTERT cells)were mixed and cocultured on metal meshes to form skin graft-like structures. Hematoxylin and eosin (HE)staining was performed to observe the structure of formed skin grafts, an immunohistochemical assay to measure the expression of HPV6 L1 protein, and electron microscopy to observe virus particles in the skin grafts. Results The linear HPV6 gene was successfully transferred into hTERT cells, and Southern blotting showed the presence of HPV6 DNA in the transferred hTERT cells. The HPV6.hTERT cells, which were cocultured with 3T3 J2 trophoblastic cells and type I rat-tail collagen, proliferated and differentiated over time, and gradually formed skin grafts giving the appearance of verrucous hyperplasia. HE staining showed that the cocultured HPV6.hTERT cells could form typical stratified structure of skin after 7 days of cultivation, and histopathologic features of HPV infection, including obvious papillomatous hyperplasia, presence of vesicular cells, hyperkeratosis and parakeratosis, could be observed after 21 days. The immunohistochemical assay showed the expression of HPV6 L1 protein in the upper portion of skin grafts, and electron microscopy revealed the presence of HPV6 virus particles in skin grafts. Conclusions The established model for preparation of tissue-engineered skin grafts using HPV 6 genome-carrying cells provides a basis for biological studies of HPV, but its application is limited to some degree.

BACKGROUND:The occurrence and development of osteoarthritis is strongly associated with immune abnormalities,and the importance of various immune cells and immune mediators in the pathogenesis of osteoarthritis has been continuously elucidated. OBJECTIVE:To review the role of immune cells and related cytokines in osteoarthritis disease,and provide new ideas for future research and prevention of osteoarthritis. METHODS:Taking"osteoarthritis,knee,macrophages,T cells,B cells,natural killer cells,dendritic cells,cytokines,inflammatory factors,immune cells"as search terms,relevant published literature was searched on CNKI,WanFang,VIP,PubMed and Web of Science databases.After reading the title and abstract for preliminary screening,98 articles were selected for review after reading the full text again. RESULTS AND CONCLUSION:In the past,it was believed that the pathogenesis of osteoarthritis was associated with cartilage wear.In recent years,studies have suggested that osteoarthritis is a chronic inflammatory state in which immune cells are widely involved.With the in-depth study of the pathogenesis of osteoarthritis,scholars believe that the pathogenesis of osteoarthritis is driven by early innate immune response,which will gradually catalyze degenerative changes and eventually lead to changes in the joint microenvironment.Various immune cells and cytokines are the key factors affecting the repair of osteoarthritis.Macrophages and natural killer cells participate in synovial inflammatory reaction,and T cell immune reaction participates in the degradation of osteoarthritis cartilage and aggravates the condition of osteoarthritis.Interleukin-1β secreted by immune cells,interleukin-6,tumor necrosis factor α,interleukin-17 and interleukin-37 play an important role in the pathophysiology of osteoarthritis,among which interleukin-1β is the most important inflammatory factor causing articular cartilage damage.Assessing immunological risk factors at the early stage of osteoarthritis can effectively treat the disease at an early stage,which can significantly reduce disability,morbidity and costs associated with osteoarthritis.At present,the immunomodulatory effect of stem cells and their derived secretions and biomaterials on the treatment of osteoarthritis has been confirmed in different experimental models,but there is still a lot of research to be done before they are used in clinical practice.With the discovery of new therapeutic targets,targeted treatment will bring new hope for the repair of clinical osteoarthritis.

Objective : To explore the general information，clinical features，imaging findings and outcome of pa- tients with drug-induced cholestatic． Methods : The clinical data of patients diagnosed as cholestatic drug-induced liver injury in recent 5 years were analyzed retrospectively，and followed up for at least 6 months. Results : There were 105 patients with drug-induced cholestatic liver injury in the hospital，the median age was 55 years old (54. 3% male) ，most of them had no specific clinical symptoms ; there were nearly 80 kinds of drugs involved，the top three were traditional Chinese medicine (34. 3% ) ，antineoplastic drugs (22. 9% ) and antibiotics ( 10. 5% ) . Among the 49 patients with magnetic resonance cholangiopancreatography ( MRCP) ，7 ( 14. 3% ) had sclerosing cholangitis-like changes ; most of the patients were combined with multiple liver-protecting and enzyme-lowering drugs ; there were 53 cured (50. 5% ) ，41 improved (39. 0% ) ，7 uncured (6. 7% ) ，and 4 died (3. 8% ) among 105 patients，and the total effective rate was 89. 5%． Conclusion Drug-induced cholestatic liver injury mainly oc- curs in elderly patients，involving many kinds of drugs，mainly traditional Chinese medicine．Drugs can also cause changes similar to sclerosing cholangitis，so drug-induced liver injury (DILI) should be used as one of the differen- tial diagnosis of cholestasis and abnormal cholangiography．Liver disease and the number of drugs have no effect on the prognosis of the patients，while low Roussel Uclaf causality assessment method (RUCAM) score and hemoglobin count，short hospitalization time and high white blood cell count are poor prognostic factors.

Objective To explore the relationship between different smoking status and hypothyroidism in six iodine-suitable areas of China. Methods A total of 8187 residents were investigated by cluster sampling in six cities, and 7448 residents were included in the survey. The height, weight, waist circumference, and blood pressure were measured by filling out epidemiological questionnaire. Blood samples were collected to detect thyroid stimulating hormone ( TSH) , thyroid peroxidase antibody ( TPOAb) , and thyroglobulin antibody ( TgAb) . Results The mean TSH, TPOAb, and TgAb positive rates in passive smoking and active smoking groups were all lower than those in non-smoking group ( all P<0.01) . In the active smoking group, the TSH value decreased by 0.023 units for every unit increase in smoking index. The positive rates of TgAb and TPOAb in both passive smoking and active smoking groups were lower than those in non-smoking group (all P<0.01). Active and passive smoking reduced the prevalence of hypothyroidism (both P<0.01). Among women, the risks of clinical hypothyroidism and subclinical hypothyroidism were reduced in both active and passive smoking groups. Besides, the risk of subclinical hypothyroidism decreased significantly when the smoking index was more than 70. In male population, the risk of subclinical hypothyroidism in active and passive smoking group decreased. Besides, the risk of clinical hypothyroidism and subclinical hypothyroidism decreased significantly when the smoking index was more than 70. Conclusion Smoking in iodine-suitable areas may reduce TSH level and the positive rates of TPOAb and TgAb.

Objective To understand the epidemiological characteristics of norovirus detection based on the diarrhea syndromic surveillance in Pudong ,Shanghai .Methods Diarrhea syndromic surveillance program was conducted in outpatient and emergency departments of 12 sentinel hospitals during 2012 -2016 .The clinical and epidemiological data of diarrheal patients were collected .The fecal specimens were also sampled . The detections for norovirus by polymerase chain reaction and gene sequencing were performed .Chi-square test or Fisher exact probability test was used to compare the detection rate .Binary logistic regression was used to explore the impact factors of norovirus infection among diarrheal patients . Results The detective rate of norovirus among diarrheal patients was 21 .59％ ,peaking from October to next March .Among all the age groups ,the detection rate was highest among patients with 25 - 64 years old .The patients with more severe diarrhea symptoms (> 5 times a day) were more likely to be infected with norovirus than those with diarrhea 3 - 5 times a day (χ2 = 21 .167 ,P< 0 .01) .Vomiting was also an indicator of norovirus infection .Patients presented with vomiting had a higher norovirus detection rate (χ2 = 198 .543 , P < 0 .01) . Norovirus G Ⅱ was the predominant genotype .Conclusions The recent epidemic of norovirus infection in diarrheal patients in Pudong new district has an apparent seasonality peaked from October to next March .Adult ,patients with vomiting and more severe diarrhea symptoms are at risk of norovirus infection .The long-term surveillance is critical for the norovirus infection control .

Background: Subclinical hypothyroidism (SCH) is the most common thyroid dysfunction, and its relationship with blood pressure (BP) has been controversial. The aim of the study was to analyze the association between SCH and newly-diagnosed hypertension. Methods: Based on data from the Thyroid disease, Iodine nutrition and Diabetes Epidemiology (TIDE) study, 49,433 euthyroid individuals and 7,719 SCH patients aged ≥18 years were enrolled. Patients with a history of hypertension or thyroid disease were excluded. SCH was determined by manufacturer reference range. Overall hypertension and stage 1 and 2 hypertension were diagnosed according to the guidelines issued by the American College of Cardiology/American Heart Association in 2017. Results: The prevalence of overall hypertension (48.7%), including stage 1 (28.9%) and 2 (19.8%) hypertension, increased significantly in SCH patients compared with euthyroid subjects. With elevated serum thyroid stimulating hormone (TSH) level, the hypertension prevalence also increased significantly from the euthyroid to different SCH subgroups, which was more profound in females or subjects aged <65 years. The age- and sex-specific regression analysis further demonstrated the same trends in the general population and in the 1:1 propensity matched population. Similarly, several BP components (i.e., systolic, diastolic, and mean arterial BP) were positively associated with TSH elevation, and regression analysis also confirmed that all BP components were closely related with SCH in female subjects aged <65 years. Conclusion The prevalence of hypertension increases for patients with SCH. SCH tends to be associated with hypertension and BP components in females younger than 65 years.