Worrying results on resignation intention for ICU physicians in China: a big data report from 34 provinces.

OBJECTIVE: The clinical work of ICU doctors is characterized by high intensity and medical risks, which lead to a highly stressful state for a long time and the occurrence of resignation due to long-term burnout. This study analyzes the correlation between the personal life, hospital work, social opinion, and psychological assessment of ICU physicians and their resignation intention. SUBJECTS AND METHODS: This study is a multicenter questionnaire on the factors influencing resignation intention among ICU physicians. The study was completed through Critical Care E Institute (CCEI) and China Calm Therapy Research Group Academic Organization (CNCSG) by contacting critical care physicians in 3-A hospitals in 34 provinces in China. The questionnaire was in electronic format, and the results were filled in using the WeChat scan code. The survey included 22 indicators which included basic information about physicians (including gender, marriage, children, and income, etc.), hospital work (weekly working hours, on night duty, hospital environment, the evaluation of hospital's emphasis on medical staff, etc.), and SCL-90 psychological assessment. RESULTS: A total of 1,749 ICU physicians completed the questionnaire. The results showed that 1,208 physicians (69.1%) intended to resign. There were statistical differences between the group's resignation intention and without resignation intention on 13 indicators. These indicators include professional title, night shift every few days, hospital hours/week, income satisfaction, work environment satisfaction, career prospect, and SCL-90 score, etc. (all p<0.05, respectively). The remaining nine indicators were not statistically different between the two groups (all p>0.05, respectively). Logistics analysis showed that working years, hospital hours (h/week), income satisfaction, work environment satisfaction, pride in hospital work, career prospects, and total SCL-90 score were all independent influences on physicians' choice of resignation intention (all p<0.05, respectively). The ROC curves' results showed that all seven indicators' predictive diagnostic value was low, with AUC areas ranging from 0.567 to 0.660. However, the combined diagnostic model of seven indicators has moderate diagnostic value. The AUC area of the model was 0.740 (95% CI: 0.718-0.760), with a sensitivity of 75.99% and specificity of 60.07%. CONCLUSIONS: Physicians' income, working years, work environment satisfaction, career prospects, and psychological well-being can influence the choice of physicians' resignation intention in Chinese intensive care units. Government administration and hospitals can develop appropriate policies to enhance doctors working in hospital, thus reducing physicians' resignation choices.

[Epidemiological characteristics of severe cases of hand, foot, and mouth disease in China, 2008-2018].

Objective: To characterize the epidemiology of severe hand, foot and mouth disease (HFMD) in China from 2008 to 2018 and provide evidence for the prevention and control of severe HFMD. Methods: The incidence data of severe HFMD cases from 2008 to 2018 were collected from the National Notifiable Infectious Diseases Reporting System of Chinese Center for Disease Control and Prevention. Descriptive epidemiological methods were used to analyze distributions, pathogen constituent and change of severe HFMD. Joinpoint regression model was used to analyze the trends of severity rate, proportion of severe cases and severe fatality rate. Results: From 2008 to 2018, a total of 157 065 cases of severe HFMD were reported in China, with an average annual case-severity rate of 1.05/100 000, a severe case proportion of 0.76% and a severity-fatality rate of 2.34%. The severity rate and the proportion of severe cases showed a downward trend after 2010, and severe fatality rate decreased significantly after 2014. The severe cases mainly occurred in infants aged ≤3 years (91.47%), more boys were affected than girls (1.78∶1). The median age of severe HFMD cases caused by EV-A71 was highest (1.99 years) and increased year by year, other enterovirus infection cases accounted for a higher proportion in infants aged ≤1 year (66.56%). The incidence peak occurred during April-July, other enteroviruses replaced EV-A71 as the predominant serotype in 2018 (61.97%). The incidence of severe HFMD were high in some provinces in southwestern, central and eastern China. Conclusion: The overall severity rate, proportion of severe cases and severe fatality rate of HFMD in the mainland of China have shown a downward trend. The predominant pathogen in some provinces has changed from EV-A71 to other enteroviruses. It is necessary to strengthen the prevention and control of HFMD in key population, high incidence seasons and areas and carry out the surveillance of various pathogens of HFMD.

[Epidemiological characteristics of fatal cases of hand, foot, and mouth disease in children under 5 years old in China, 2008-2018].

Objective: To understand the epidemiological characteristics and risk factors of fatal cases of hand, foot, and mouth disease (HFMD) in children under 5 years old in China from 2008 to 2018, and provide evidence for the development of targeted prevention and control measures and reduction of the incidence of fatal HFMD cases. Methods: The incidence data of reported HFMD cases in China during 2008-2018 were collected from the National Notifiable Disease Surveillance Reporting System of China for the analyses on the demographic characteristics, spatial distribution, diagnosis or reporting and pathogen spectrum of the HFMD cases. Then the risk factors causing deaths were analyzed by using logistic regression model. Results: From 2008 to 2018, a total of 3 646 fatal cases of HFMD in children under 5 years old were reported in China. There were more fatal HFMD cases in boys than in girls (1.82∶1), the death mainly occurred in age group 0 to 2 years (87.71%). Adjusted mortality rate of HFMD in children under 5 years old in China declined from 0.87 per 100 000 in 2010 to 0.11 per 100 000 in 2018 (APC=-23.20%). In the 2 523 laboratory-confirmed deaths, 2 323 (92.07%) were EV-A71 infections, but the constituents of CV-A16 and other enterovirus infections increased. The interval from onset to diagnosis M=2(P(25)-P(75):2-4)d. The interval from onset to death M=3(P(25)-P(75):2-4)d. Age between 0 and 1 years, EV-A71 infection, longer interval between onset and diagnosis, and living in rural area were the risk factors causing fatal HFMD cases. Conclusions: The number of the fatal cases, the rate of mortality and case fatality HFMD in China had shown downward trends since 2010. EV-A71 is still the main pathogen causing fatal cases, but we should pay more attention to gene pattern of the other enteroviruses except EV-A71 and CV-A16. To reduce the risk of the fatal cases we should strengthen the health education about the immunization of EV-A71 inactivated vaccines and reduce the interval from onset to diagnosis in young children in western provinces and rural areas.

[Application of moving epidemic method in establishing epidemic intensity threshold of hand, foot, and mouth disease in southern China].

Objective: To evaluate the incidence intensity of hand, foot, and mouth disease (HFMD) in 2018/2019 season in southern China by Moving Epidemic Method (MEM), and compare the intensity among provinces, so as to provide basis for optimizing the allocation of public health resources. Methods: The weekly incidence data of HFMD of children under 5 years old in 15 provinces of southern China from March 1, 2012 to February 28, 2019 were collected from Disease Surveillance Reporting System of Chinese Center for Disease Control and Prevention, and the epidemic intensity threshold of each province in southern China during this period was calculated and evaluated by MEM. Results: In the first incidence peak of 2018/2019 HFMD season, in 15 provinces in the south China, 6 provinces (Jiangsu, Zhejiang, Jiangxi, Chongqing, Sichuan and Yunnan) reported very high incidence rates in children under 5 years old while Guangdong, Guangxi and Hainan provinces had low incidence level. In the second incidence peak, the incidences in 6 provinces (Shanghai, Jiangsu, Zhejiang, Chongqing, Sichuan and Yunnan) reached very high levels. The incidences in remaining provinces also reached medium or high levels. In most provinces, the thresholds in the first incidence peak were higher than those in the second incidence peak, but Chongqing and Sichuan were different. The results of model validation showed that the sensitivity and specificity of MEM were higher than 70% except for Hainan, Chongqing and Yunnan. Conclusions: For southern provinces with two incidence peaks in HFMD season, MEM can be used to determine the epidemic intensity thresholds of different incidence peaks by dividing the disease season to analyze the incidence intensity of HFMD in different stages. The epidemic intensity threshold established by MEM integrates the historical data, and the province (city) with extremely high epidemic level identified represents that the province (city) has an abnormal increase compared with the historical incidence level, which requires more attention from all areas and timely implementation of prevention and control measures.

[Epidemiological characteristics of dengue fever outbreaks in China, 2015-2018].

Objective: To analyze the epidemiological characteristics of outbreaks of dengue fever in China from 2015 to 2018, and provide evidence for the prevention and control of dengue fever. Methods: We extracted the incidence data of dengue fever from China Disease Prevention and Control Information System, Public Health Emergency Reporting Management Information System and Vector Biological Monitoring System, and explored the epidemiological characteristics of the outbreaks in the past four years. Excel 2010 software and SPSS 20.0 software were used for data processing and analysis, ArcGIS 10.5 software was used for mapping. Results: A total of 111 outbreaks of dengue fever were reported nationwide from 2015 to 2018, involving 12 490 cases, accounting for 73.7% of the total cases in China. These outbreaks occurred in 85 counties and districts of 4 provinces, namely Guangdong (77 outbreaks), Yunnan (14 outbreaks), Zhejiang (8 outbreaks) and Fujian (8 outbreaks). The outbreaks occurred during May-November. Small-scale outbreaks with no more than 10 cases ended within 30 days (28/34, 82.4%) and larger-scale outbreaks lasted for several months. Dengue virus type 1 and type 2 were the main epidemic pathogens of dengue fever outbreaks in China. The outbreaks mainly occurred in areas with high population density and poor sanitary environment. There were significant differences in the age and occupational composition of the cases in the main outbreak provinces. Conclusions: Outbreaks of dengue fever can been seen in more areas in China, even in high latitudes areas. The epidemiologic characteristics of the outbreaks were different among provinces, showing as port type, rural type and urban type. Each province should adjust the control strategies accordingly.

[A systematic review of the economic burden of influenza in China].

Objectives: To understand the status of studies about influenza economic burden in mainland China and summarize their major results. Methods: The words of influenza, flu, cost, economic, burden, effectiveness, benefit, utility, China, and Chinese, were used as search keywords. Journal papers published during 2000-2018 were searched from Chinese electronic databases (CNKI and Wanfang) and English electronic databases (PubMed, Web of science, EconLit and Cochrane Library). The language of literature was restricted to Chinese and English. A total of 23 effective documents were included, and the descriptive characteristics, research indexes and methods included in the literature were analyzed. The monetary unit used in this review is Chinese Yuan (CNY). Results: The 23 study sites were mainly in the relatively developed and populous regions. The total cost per capita of laboratory-confirmed influenza,of all age-group was reported in 6 literatures, and only 4 literatures reported it in out-patients (range: 768.0-999.9 CNY), Only one study reported this indicator in inpatients (9 832.0 CNY). One literature reported the total cost per capita of influenza-like illness,, which was 205.1 CNY. And one literature reported that the direct medical cost of inpatients per capita in children under 5 years of age was 6 072.0 CNY while two literature reported this index for the elderly over 60 years of age, ranging from 14 250.0 to 19 349.1 CNY. Four articles reported the economic burden of influenza in urban and rural areas, one of which showed that the related expenses of urban influenza inpatients accounted for 31% of the average annual income, while which for the rural flow was 113%. Conclusion: The average economic burden of lab-confirmed influenza case is higher than that of influenza-like illness, and there are differences in outpatient indirect expenses and inpatients direct medical expenses. The direct medical burden for the hospitalized 60-years-and-beyond influenza case group is heavier thar other age group. By region, the influenza associated individual economic burden in rural area is higher than that of urban area..

[The mortality burden of influenza in China: a systematic review].

Objective: To systematically review the mortality burden study of influenza in mainland China. Method: "influenza", "flu", "H1N1", "pandemic", "mortality", "death", "fatality", "burden", "China" and "Chinese" were used as keywords, and a systematic literature search was conducted to identify articles in three English databases (PubMed, Web of Science and Embase) and three Chinese database (CNKI, WanFang and VIP) during 1990-2018 (excluding Hong Kong, Macao and Taiwan). The language of literature was restricted to Chinese and English. The inclusion criteria were human-oriented researches with method based on population, and research indexes included mortality and excess mortality. The exclusion criteria were non-primary research materials, predictive research and research on the burden of avian influenza related deaths. A total of 17 literatures were included, and the basic information to descriptive characteristics, methodology of modeling and the corresponding results were extracted. Results: All the 17 studies adopted indirect statistical models, with 14 of which adopted the regression model, and all the research index was excess mortality. All causes (16 studies), respiratory and circulatory diseases (14 studies) and pneumonia and influenza (10 studies) were the main causes of death associated with influenza. Influenza associated mortality burden in the elderly was higher, with the lowest excess mortality rates of all causes, respiratory and circulatory diseases, pneumonia and influenza being 49.57, 30.80 and 0.69 per 100 000 people, and the highest rates being 228.16, 170.20 and 30.35 per 100 000 people, respectively. In the non-elderly, the corresponding lowest rates were -0.27, -0.08 and 0.04 per 100 000 people respectively, and the highest rates were 3.63, 2.6 and 0.91 per 100 000 people, respectively. The influenza-related excess mortality was higher in the north, with a minimum of 7.8 per 100 000 and a maximum of 18.0 per 100 000, and slightly lower in the south, with a minimum of 6.11 per 100 000 and a maximum of 18.7 per 100 000. There were also differences in deaths caused by different influenza virus subtypes, with influenza A(H3N2) and influenza B virus possibly posing a heavier mortality burden. Conclusions: Studies on influenza mortality burden is mainly based on indirect model and urban level in China. The mortality burden of influenza in the elderly, the northern and subtype A(H3N2) and B were more severe.

[Clipping for large paraclinoid internal carotid artery aneurysms by non-fluoroscopic occlusion via a micro-bone window frontolateral approach].

Objective: To evaluate the clinical value and outcomes of technical improvement of hybrid operatical clipping for large paraclinoid internal carotid artery aneurysms. Methods: A review was conducted on 18 cases of large paraclinoid internal carotid artery aneurysm which were clipped by balloon non-fluoroscopic occlusion of the parent artery via a micro-bone window frontolateral approach in hybrid operating room at Neurosurgery Department of Tianjin Medical University General Hospital from June 2014 to December 2017. There were 8 males and 10 females with age of (63±4) years. There were 6 cases of unruptured aneurysm and 12 cases of ruptured aneurysm of subarachnoid hemorrhage (6 cases of grade Ⅱ, 4 cases of grade Ⅲ and 2 cases of grade Ⅳ in Hunt-Hess classification). Frontolateral approach incision (average length of about 5 cm) and bone window about 3 cm×3 cm were performed. No incision of the neck was needed to expose the internal carotid artery for temporary occlusion. In the operation, the balloon was slowly pushed to the preset position of the internal carotid artery under non-fluoroscopy. The balloon was expanded to block the blood flow of internal carotid artery. Then aneurysm was clipped. The balloon was loosened and retraced to the guiding catheter after clipping. The clipping condition was examined by cerebral angiography. If there was residual aneurysm neck or stenosis of the parent artery, the balloon was pushed under non-fluoroscopy again to temporary occlusion and the clip was adjusted until the aneurysm neck was clamped satisfactorily. Results: Eighteen aneurysms were successfully clipped in hybrid operating room. Fourteen aneurysms showed complete occlusion of the aneurysm neck and no stenosis of the parent artery. Four cases showed residual aneurysm neck after clipping by intraoperative angiography, then aneurysms were clipped satisfy by adjusting the aneurysm clip. The patients were followed up for 3 months to 1 year. Ten patients recovered well (modifed Rankin score (mRS): 0), and 3 patients had no obvious disability (mRS: 1). Two patients with Hunt-Hess grade Ⅲ were slightly disabled (mRS: 2). 1 patients with Hunt-Hess grade Ⅲ were moderately disabled (mRS: 3). 1 patients with Hunt-Hess grade Ⅳ were severely disabled (mRS: 4). One elderly patients with Hunt-Hess grade Ⅳ were seriously disabled (mRS: 5). Conclusions: Application of balloon non-fluoroscopic occlusion clipping for large paraclinoid internal carotid artery aneurysm via a micro-bone window frontolateral approach is safe, effective and minimally invasive.

Effect of TAGLN2 in the regulation of meningioma tumorigenesis and development.

OBJECTIVE: To explore the role of transgelin-2 TAGLN2 in the development and progression of meningioma and the potential regulatory. MATERIALS AND METHODS: TAGLN2 knockdown expression and overexpression in vitro models were constructed using lentivirus in meningioma cell line CH157; their corresponding transfection efficiencies were verified by qRT-PCR and Western Blot. Actions of TAGLN2 on the proliferation of meningioma cells were explored by CCK8 and colony formation assays. The effect of TAGLN2 on invasion of meningioma cells was analyzed by transwell cell invasion assay. Biological function of TAGLN2 on apoptosis of meningioma cells was determined by flow cytometry. Finally, Western Blot was used to investigate the detailed mechanism of TAGLN2 on regulating the biological functions of meningioma cells. RESULTS: After down-regulating the expression of TAGLN2, there were significantly decreased capacities of cells proliferation and colony formation of meningioma cells, meanwhile, cell invasion was significantly decreased but the apoptosis rate was increased. On the contrary, up-regulation of TAGLN2 expression, the proliferation, colony formation ability were significantly increased as well as the invasion capacity, whilst apoptosis rate was decreased. Western Blot showed that expressions of p-PI3K and p-AKT were inhibited after knockdown of TAGLN2, which were significantly increased after TAGLN2 was overexpressed. CONCLUSIONS: TAGLN2 can affect the proliferation, invasion and apoptosis of meningioma cells and may participate in the development of meningioma through regulating the PI3K/AKT signaling pathway.

[The role of smoking and metabolic enzyme polymorphisms in the organic solvent induced chronic encephalopathy].

OBJECTIVE: The organic solvents and other exogenous compounds of metabolic enzymes genetic variation may affect the risk of the toxic effect of organic solvents exposure. Therefore, this research we observed the glutathione transferase M1 and T1 (GSTM1, GSTT1) deletion mutation genotype, two kinds of microsomal epoxide hydrolase (mEPHX) genetic polymorphism, organic solvents exposure and smoking effection in chronic cases of toxic encephalopathy (CTE) correlation. METHODS: The object was 115 patients who had a long history of organic solvents exposure, were divieded into two groups: CTE (n=83) , no CET (n=32) according to clinical diagnosis. DNA was isolated from patients in white blood cells through the multiple-polymerase chain reaction to determine the loss of GSTM1 and GSTT1 genotype. two kinds of mEPHX polymorphism were analysised through the PCR-RFLP (restriction fragment length polymorphism). RESULTS: The relative risk has obviously improved when lack of GSTM1 genotypes to CTE (RR=2.35, 95% CI 2.35 0.96). in according to the patient's Smoking condition and classify genotype, patients lack of GSTM1 genotypes had a significantly higher risk CTE than GSTM1+genotype patients (RR=3.13, 95% CI 3.13 1.2) , both mEPHX polymorphisms had nothing to do with an increased risk of CTE. CONCLUSION: The GSTM1 genotypes played an important role in the organic solvent induced the CTE of susceptibility.it was Influenced by the interaction between smoking at the same time.

Effects of intracutaneous injections of sterile water in patients with acute low back pain: a randomized, controlled, clinical trial

Intracutaneous sterile water injection (ISWI) is used for relief of low back pain during labor, acute attacks of urolithiasis, chronic neck and shoulder pain following whiplash injuries, and chronic myofascial pain syndrome. We conducted a randomized, double-blinded, placebo-controlled trial to evaluate the effect of ISWI for relief of acute low back pain (aLBP). A total of 68 patients (41 females and 27 males) between 18 and 55 years old experiencing aLBP with moderate to severe pain (scores ≥5 on an 11-point visual analogue scale [VAS]) were recruited and randomly assigned to receive either ISWIs (n=34) or intracutaneous isotonic saline injections (placebo treatment; n=34). The primary outcome was improvement in pain intensity using the VAS at 10, 45, and 90 min and 1 day after treatment. The secondary outcome was functional improvement, which was assessed using the Patient-Specific Functional Scale (PSFS) 1 day after treatment. The mean VAS score was significantly lower in the ISWI group than in the control group at 10, 45, and 90 min, and 1 day after injection (P<0.05, t-test). The mean increment in PSFS score of the ISWI group was 2.9±2.2 1 day after treatment, while that in the control group was 0.9±2.2. Our study showed that ISWI was effective for relieving pain and improving function in aLBP patients at short-term follow-up. ISWI might be an alternative treatment for aLBP patients, especially in areas where medications are not available, as well as in specific patients (e.g., those who are pregnant or have asthma), who are unable to receive medications or other forms of analgesia because of side effects.

Effects of intracutaneous injections of sterile water in patients with acute low back pain: a randomized, controlled, clinical trial.

Intracutaneous sterile water injection (ISWI) is used for relief of low back pain during labor, acute attacks of urolithiasis, chronic neck and shoulder pain following whiplash injuries, and chronic myofascial pain syndrome. We conducted a randomized, double-blinded, placebo-controlled trial to evaluate the effect of ISWI for relief of acute low back pain (aLBP). A total of 68 patients (41 females and 27 males) between 18 and 55 years old experiencing aLBP with moderate to severe pain (scores ≥5 on an 11-point visual analogue scale [VAS]) were recruited and randomly assigned to receive either ISWIs (n=34) or intracutaneous isotonic saline injections (placebo treatment; n=34). The primary outcome was improvement in pain intensity using the VAS at 10, 45, and 90 min and 1 day after treatment. The secondary outcome was functional improvement, which was assessed using the Patient-Specific Functional Scale (PSFS) 1 day after treatment. The mean VAS score was significantly lower in the ISWI group than in the control group at 10, 45, and 90 min, and 1 day after injection (P<0.05, t-test). The mean increment in PSFS score of the ISWI group was 2.9±2.2 1 day after treatment, while that in the control group was 0.9±2.2. Our study showed that ISWI was effective for relieving pain and improving function in aLBP patients at short-term follow-up. ISWI might be an alternative treatment for aLBP patients, especially in areas where medications are not available, as well as in specific patients (e.g., those who are pregnant or have asthma), who are unable to receive medications or other forms of analgesia because of side effects.

Prevention of etomidate-induced myoclonus during anesthetic induction by pretreatment with dexmedetomidine

Myoclonus induced by etomidate during induction of general anesthesia is undesirable. This study evaluated the effect of dexmedetomidine (DEX) pretreatment on the incidence and severity of etomidate-induced myoclonus. Ninety patients undergoing elective surgical procedures were randomly allocated to three groups (n=30 each) for intravenous administration of 10 mL isotonic saline (group I), 0.5 µg/kg DEX in 10 mL isotonic saline (group II), or 1.0 µg/kg DEX in 10 mL isotonic saline (group III) over 10 min. All groups subsequently received 0.3 mg/kg etomidate by intravenous push injection. The incidence and severity of myoclonus were recorded for 1 min after etomidate administration and the incidence of cardiovascular adverse events that occurred between the administration of the DEX infusion and 1 min after tracheal intubation was recorded. The incidence of myoclonus was significantly reduced in groups II and III (30.0 and 36.7%), compared with group I (63.3%). The incidence of severe sinus bradycardia was significantly increased in group III compared with group I (P<0.05), but there was no significant difference in heart rate in groups I and II. There were no significant differences in the incidence of low blood pressure among the 3 groups. Pretreatment with 0.5 and 1.0 µg/kg DEX significantly reduced the incidence of etomidate-induced myoclonus during anesthetic induction; however, 0.5 µg/kg DEX is recommended because it had fewer side effects.

Prevention of etomidate-induced myoclonus during anesthetic induction by pretreatment with dexmedetomidine.

Myoclonus induced by etomidate during induction of general anesthesia is undesirable. This study evaluated the effect of dexmedetomidine (DEX) pretreatment on the incidence and severity of etomidate-induced myoclonus. Ninety patients undergoing elective surgical procedures were randomly allocated to three groups (n=30 each) for intravenous administration of 10 mL isotonic saline (group I), 0.5 µg/kg DEX in 10 mL isotonic saline (group II), or 1.0 µg/kg DEX in 10 mL isotonic saline (group III) over 10 min. All groups subsequently received 0.3 mg/kg etomidate by intravenous push injection. The incidence and severity of myoclonus were recorded for 1 min after etomidate administration and the incidence of cardiovascular adverse events that occurred between the administration of the DEX infusion and 1 min after tracheal intubation was recorded. The incidence of myoclonus was significantly reduced in groups II and III (30.0 and 36.7%), compared with group I (63.3%). The incidence of severe sinus bradycardia was significantly increased in group III compared with group I (P<0.05), but there was no significant difference in heart rate in groups I and II. There were no significant differences in the incidence of low blood pressure among the 3 groups. Pretreatment with 0.5 and 1.0 µg/kg DEX significantly reduced the incidence of etomidate-induced myoclonus during anesthetic induction; however, 0.5 µg/kg DEX is recommended because it had fewer side effects.

Solid-phase photocatalytic degradation of polyethylene-goethite composite film under UV-light irradiation.

A novel photodegradable polyethylene-goethite (PE-goethite) composite film was prepared by embedding the goethite into the commercial polyethylene. The degradation of PE-goethite composite films was investigated under ultraviolet light irradiation. The photodegradation activity of the PE plastic was determined by monitoring its weight loss, scanning electron microscopic (SEM) analysis and FT-IR spectroscopy. The weight of PE-goethite (1 wt%) sample steadily decreased and led to the total 16% reduction in 300 h under UV-light intensity for 1 mW/cm(2). Through SEM observation there were some cavities around the goethite powder in the composite films, but there were few changes except some surface chalking phenomenon in pure PE film. The degradation rate could be controlled by changing the concentration of goethite particles in PE plastic. The degradation of composite plastic initiated on PE-goethite interface and then extended into polymer matrix induced by the diffusion of the reactive oxygen species generated on goethite particle surface. The photocatalytic degradation mechanism of the composite films was briefly discussed.

Stage specificity of novel growth factor expression during development of proliferative vitreoretinopathy.

OBJECTIVE: To compare the relative levels of connective tissue growth factor (CTGF), platelet-derived growth factor alpha (PDGF-AA), and hepatocyte growth factor (HGF) in glial and retinal pigment epithelial (RPE) cells of epiretinal membranes from proliferative vitreoretinopathy (PVR). METHODS: A total of 37 PVR membranes, of various stages, underwent fluorescent immunohistochemisty and confocal laser scanning microscopy to localize CTGF, HGF, and PDGF-AA in RPE and glial cells. RESULTS: Numerous RPE, and relatively fewer glial cells, were found in all stages of PVR. CTGF immunoreactivity increased from early to late stage PVR and was principally expressed by RPE cells in early stage, and by glial cells in late stage PVR. HGF, expressed by both RPE and glial cells, was principally expressed in mid-stage PVR. PDGF-AA, expressed by both cell types, demonstrated a uniform level of staining throughout all stages of PVR. CONCLUSIONS: RPE and glial cells contribute to the expression of CTGF, HGF, and PDGF-AA during PVR, but with specific developmental patterns. PDGF-AA is expressed uniformly throughout all stages of PVR, while HGF expression peaks during mid stage, and CTGF expression is highest during late stage PVR. These results allow for the development of stage-specific therapeutics for PVR that may allow targeting of the early proliferative and/or the late tractional stages of PVR.

Vitreous leptin levels in retinal disease.

BACKGROUND/AIMS: The purpose of this study was to investigate the relationship between vitreous leptin levels and retinal diseases. METHODS: Levels of vitreous leptin were evaluated in proliferative diabetic retinopathy (PDR) and a variety of other retinopathies including: macular disease, neovascular maculopathies, primary retinal detachments, and vascular occlusive disease. RESULTS: In patients with PDR (N=7), the average vitreous level of leptin (37.4 ng/ml) was significantly higher than that in patients with PVR (<1.0 ng/ml, P<0.05). Vitreous leptin level in patients with PVR or macular disease (N=18), with or without diabetes, was not significantly different from the control subjects who had retinal detachment only (N=7). CONCLUSION: The results show that the leptin level in vitreous taps is elevated in PDR. We suggest that leptin plays an active role in PDR.

The role of leptin in choroidal neovascularization.

PURPOSE: The purpose of this study was to investigate the role of leptin in choroidal neovascularization. METHODS: We examined the localization of leptin by immunohistochemistry in nine choroidal neovascular membranes surgically excised from patients with age-related macular degeneration, idiopathic choroidal neovascularization, and ocular histoplasmosis. Controls included omission of primary antibody, use of an irrelevant primary antibody and leptin staining of posterior segment of four normal donor eyes. RESULTS: Leptin was present in eight membranes and appeared vesicular, within the cytoplasm. The more vascular membranes and those consisting of a larger number of retinal pigment epithelium cells were associated with greater leptin staining. Leptin was not seen in the posterior segment of the four normal eyes. CONCLUSION: We suggest that leptin plays an active role in choroidal neovascularization, although further experiments are necessary to establish a causal relationship.

Natural history of choroidal neovascularization induced by vascular endothelial growth factor in the primate.

BACKGROUND: A new model of choroidal neovascularization (CNV) has been developed in the primate by implanting vascular endothelial growth factor (VEGF)-impregnated microspheres in the subretinal space. METHODS: CNV was induced in Macaca mulatta monkeys by implanting VEGF-impregnated gelatin microspheres in the subretinal space. Progression of CNV was followed for 24 weeks after surgery using fluorescein angiography. Eyes were enucleated at various time points, and lesions were evaluated for evidence of CNV by light microscopy and by immunohistochemical staining. RESULTS: CNV developed in 12 (92%) of 13 eyes. Fluorescein leakage was first observed in the 2nd postoperative week and was apparent for the following 12 weeks. CD31 staining for endothelial cells was first observed at day 7 and was evident for the following 8 weeks. Glial fibrillary acidic protein staining revealed a glial adhesion between the proliferative membrane and the retina at 6 weeks after implantation. Smooth muscle actin-positive cells were found a +2 weeks and remained prominent for at least the next 6 weeks. Cytokeratin-positive retinal pigment epithelial (RPE) cells, first identified in the proliferative membrane at day 3, predominated throughout the growth of the membrane. Macrophages (RAM-II positive) were present at day 3 but were no longer observed after day 7. CONCLUSION: In monkeys, subretinal implantation of VEGF-impregnated gelatin microspheres leads to the development of CNV. Early, disciform and reparative stages of CNV were observed, similar to those seen in humans. This model will be useful for studying the pathogenesis of CNV and for evaluating potential treatment strategies.

Transplantation of autologous iris pigment epithelium to the subretinal space in rabbits.

BACKGROUND: Transplantation of autologous iris pigment epithelium (IPE) into the subretinal space has been suggested as one approach for the treatment of age-related macular degeneration. Autologous rabbit IPE cells were transplanted to the subretinal space to define the technique of transplantation and examine the survival of the transplanted cells. METHODS: Autologous IPE cells were harvested by iridectomy and transplanted directly to the subretinal space of the fellow eye in 25 rabbits, using the parsplana approach. Animals were killed over a period of 5 months, and the retinas were examined morphologically by light and electron microscopy. RESULTS: Autologous IPE cells survived and formed a polarized monolayer above the retinal pigment epithelium in the subretinal space, with apical microvilli adjacent to photoreceptors. Fragments of phagocytosed photoreceptor rod outer segments were observed in phagosomes in the cytoplasm of IPE cells. Adjacent rod outer segments remained healthy throughout the experimental period. No signs of a cell-mediated immunologic response were observed. CONCLUSIONS: Our results show that in rabbits, autologous IPE cells transplanted to the subretinal space survive and do not adversely affect the photoreceptors. These results suggest that in humans, IPE cells might provide a substitute for retinal pigment epithelium cells as autologous transplants for the treatment of age-related macular degeneration.