Objective: So far, CT back projection technology is already quite mature, this article is a basic research for CT back projection technology, which uses software method to realize back-projection technology, so that you can have a better under-standing of CT back-projection technology. It uses computer soflware programming to realize computer simulation of CT back-projection reconstruction: algorithm is CT back projection algorithm. While realizing back-projection reconstruction, we can choose a suitable faltering function to process received image data in finquency domain, so as to achieve the purpose of the elimination of simple back-projection arising from star-shaped artifact. Methods: The programming environment uses VC soft-ware platform integrated development environment ODE). It bases on the CT filtering back-projection reconstruction algorithm and develops a PC software of graphic user interface. By choosing the value of the various parameters related to the back-pro-jection, we can obtain different effect of back-projection reconstruction image, so that we can compare the result of different pa-rameters to get important factors which effects CT filter back-projection most. Results: We realize the simulation of image re-construction of standard phantom. The interface is easy, so makes it very convenient for deeper understanding of back-projec-tion reconstruction, at the same time the filtering function based on the frequency domain also partly eliminates the star artifact caused by reconstruction process. The reconstruction image of the standard phantom achieves the desired effect. Conclusions: The software simulation of the back-projectiun reconstruction can show the process of recoustruction clearly. By change the val-ue of the parameters, we can have a better understanding of the reconstruction algorithm, so that we can find more suitable fil-tering function.

Background Fungal keratitis has a high incidence in China and its clinical treatment is very difficult,and its etiology diagnosis and appraisal is the premise to improve the prognosis of disease.With the changes of regional environment and climate in recent years,whether the spectrum of fungal keratitis change in South China is remarkable.Objective The purpose of this study was to investigate recent pathogenic distribution of fungal keratitis in South China area.Methods The consecutive fungal culture resuhs of 3 350 purulent keratitis at Zhongshan Ophthalmic Center from January 2009 to December 2014 were retrospectively reviewed.The positive rate of fungal culture,genus or species distribution,seasonal distribution and different term distribution were analyzed.Results The culture-positive rate was 31.34％ in this study (1 050/3 350),and the average culture-positive number was 175 strains per year.In the positive fungus,the highest positive rate was Fusarium SP (32.10％,337/1 050),and followed by Aspergillus SP (25.71％,270/1 050),Heminthosporium SP (14.29 ％,150/1 050) and Mucor SP (9.14％,96/1 050).The fungal culture-positive rate was 36.05％ (367/1 018) in 2009 to 2010,32.45％ (324/1 014) in 2011 to 2012,and 26.86％ (354/1 318) in 2013 to 2014,respectively,with a significant difference among the three periods (x2 =22.37,P＜0.01),showing a decreasing tendency of incidence.Two hundreds and sixtyone strains were isolated from January to March (31.15 ％,261/838),182 strains from April to June (25.53 ％,182/713),237 strains from July to September (30.00％,237/790),370 strains from October to December (36.67％,370/1 009),showing a statistically significant difference among them (x2 =25.19,P ＜ 0.01).The number of infectious strains was most during October to December and fewest during April to June.Conclusions The leading pathogenic fungi of fungal keratitis is Fusarium SP and followed by Aspergillus SP,Helminthosporium SP,Mucor SP in turn.Fungal keratitis is usually prevalent from October to December,and its incidence is still rising in Chinese mainland recently.However,the increasing tendency in South China has been prevented in recent six years.

Objective To analyze the status of healthcare-associated infection(HAI)and characteristics of patho-gens in patients with traumatic brain inj ury and cerebrovascular diseases,and evaluate prevention and control meas-ures.Methods Clinical data of 236 patients with traumatic brain injury and cerebrovascular diseases in a hospital from 2008 to 2010 were analyzed retrospectively.Results A total of 29 patients developed 50 times of HAI,HAI rate was 12.29%,HAI case rate was 21.19%,HAI case rate of respiratory system,urinary system,oral cavity, gastrointestinal tract,skin and soft tissue,and other sites was 46.00%(n=23),30.00%(n=15),8.00%(n=4), 6.00%(n=3),4.00%(n=2),and 6.00%(n=3)respectively.A total of 69 pathogenic strains were detected,per-centage of gram-negative bacteria was 65.22%(n=45),the major were Pseudomonasaeruginosa(n=17),Klebsiel-lapneumoniae(n=12),Escherichiacoli(n=10),and Acinetobacterbaumannii(n=4);percentage of gram-positive bacteria was 30.43%(n=21),the major were Staphylococcusaureus(n=11),Staphylococcusepidermidis (n=7), Streptococcus spp.(n=2);percentage of fungi was 4.35%(n=3).Conclusion HAI in patients with traumatic brain inj ury and cerebrovascular diseases is high,the main infection site is respiratory system,the main pathogens are gram-negative bacteria.Preventive and control measures should be taken accordingly.

Objective To investigate the clinical efficacy of sodium nitroprusside on the treatment of pulmonary edema in elderly patients with heart failure. Methods 50 elderly cases with heart failure and pulmonary edema From January 2015 to January 2017 were divided into the control group and the observation group according to the different treatment methods. The control group were received conventional therapy, the observation group were given conventional drug combined with sodium nitroprusside. The experimental data was recorded and compared. To investigate the effect of sodium nitroprusside on the rescue of elderly heart failure and pulmonary edema. Results The clinical effect in the observation group is better than that in the control group. The protein related indexes about heart failure and pulmonary edema were significantly improved (P<0.05). The difference of adverse reaction rate in the two groups has no statistically significat. Conclusion Conventional drug therapy combined with sodium nitroprusside were used on the treatment of elderly patients with heart failure, pulmonary edema, which can improve the clinical symptoms, related serum protein, without increasing the incidence of adverse reactions, it is worthy of clinical application.

Objective To investigate the correlation between the level of postprandial blood glucose (PBG)and the incidence of coronary artery disease(CAD). Methods Eighty-five patients performed coronary angiography with abnormal blood glucose levels were divided into 3 groups according the blood glucose levels: impaired fasting glucose(IFG)group(28 cases), impaired glucose tolerance(IGT)group(29cases)and diabetes mellitus(DM)group(28 cases). The detection rate and the extent of CAD were observed. The risk factors of CAD in 3 groups such as C-reactive protein(CRP),carotid artery intima-media thickness(CIMT), blood lipids, blood pressure, body mass index(BMI)and the correlation with CAD were analyzed. Results Sixty-two cases were confirmed CAD by coronary angiography. The incidence rate of CAD in IGT group[79.3%(23/29)]and DM group[85.7%(24/28)]was significantly higher than that in IFG group[53.6%(15/28)](P ＜ 0.01). The incidence rate of CAD in DM group was higher than that in IGT group, but there was no significant difference(P ＞ 0.05). The incidence rate of two-lesion and three-lesion in IGT group and DM group were significantly higher than those in IFG group(P＜ 0.01). The incidence rate of two-lesion and three-lesion in DM group were higher than those in IGT group, but there was no significant difference(P＞0.05). The levels of CRP, CIMT, BMI, triacylglycerol(TG)and systolic blood pressure(SBP)were higher and HDL-C was lower in IGT group and DM group than those in IFG group(P ＜ 0.01 or ＜ 0.05).The levels of CRP,TG and SBP were higher in DM group than those in IGT group(P＜0.05). Correlation analysis showed, in IGT group and DM group,2 h PG had significantly positive correlation with CRP, CIMT,B MI, TG(P＜0.05 or＜0.01), and had significantly negative correlation with HDL-C(P＜0.05 or ＜0.01).Conclusions PBG is closely related with the development of CAD.IGT patients should be intervened as early as possible, which can be effective in preventing cardiovascular events.

BACKGROUND:Long-term patency rate of smal-caliber artificial blood vessels is stil the most important issue to be solved.
OBJECTIVE:To review the materials and fabrication technologies of smal-caliber artificial blood vessels as wel as endothelialization of smal-caliber artificial blood vessels.
METHODS:A computer-based search of PubMed (2000-2013) and Wanfang database (2003-2013) was done for relevant articles using the key words of“smal-caliber, vascular graft, electrospun, layer-by-layer assembly, endothelialization”in English and Chinese, respectively. A total of 125 articles were retrieved, and final y, 41 were included for further analysis.
RESULTS AND CONCLUSION:At present, smal-caliber vascular graft materials include natural biological materials, biodegradable polymers, composite materials and xenogeneic biomaterials. Preparation technologies of smal-caliber artificial blood vessels mainly include electrospinning, self-assembly, rapid prototyping, and gel spinning. Numerous methods can elicit endothelialization of smal-caliber artificial blood vessels, but each method has its flaws and cannot ensure long-term patency radical y. With the development and diversification of preparation technologies and in-depth study of endothelialization of vascular prostheses, the long-term patency of smal-caliber artificial blood vessels wil gradual y be resolved.

Objective To explore the diagnostic value of combined bedside detection of aminoterminal pro-B-type natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI) in the diagnosis of cardiac dyspnea. Methods A total of 120 patients with dyspnea admitted in our department from June 2014 to February 2016 were included in this study. At the time of admission, NT-proBNP and cTnI levels were measured by bedside test. Values of NT-proBNP>300 ng/L or cTnI>0.16 mg/L were defined as positive for cardiac dyspnea. According to the final diagnosis, patients were divided into two groups:cardiac dyspnea group (n=68) and pulmonary dyspnea group (n=52). At the same time, 30 healthy people were selected as control group. Values of NT-proBNP and cTnI were used for statistical analysis between the three groups. The sensitivity and specificity of NT-proBNP, cTnI and cTnI+NT-proBNP were compared between three groups. Results The levels of NT-proBNP and cTnI were significantly higher in pulmonary dyspnea group and cardiac dyspnea group than those in the control group, and the levels were significantly higher in cardiac dyspnea group than those of pulmonary dyspnea group (P<0.01). The detection sensitivity of NT-proBNP and cTnI alone was 67.65% and 52.94%, combined detection of both was up to 94.12%. The specificity of NT-proBNP and cTnI detection alone was 70.00% and 53.33%, respectively, and combined detection of both was up to 86.67%. The sensitivity of NT-proBNP+cTnI was significantly higher than that of NT-proBNP and cTnI alone (P<0.05), but there was no significant difference in the specificity between combined detection andindividual detection of NT-proBNP. The positive predictive value of the combined detection in the diagnosis of cardiac dyspnea was 94.12%(64/68), and the negative predictive value was 86.67%(26/30). Conclusion Bedside detection with combination of cTnI and NT-proBNP has important clinical application value in the rapid diagnosis of cardiac dyspnea, which is a rapid clinical testing method.

Objective To investigate the influence of chronic fluorosis on protein kinase Cβ (PKCβ)/p66shc signal pathway in the brain of rats,and reveal the molecular mechanism of brain damage.Methods According to body weight by the random number table method thirty SD rats were divided into three groups of 10 each (half females and half males),the normal control group [less than 0.5 mg/L of fluorine (prepared with NaF) in drinking water],low fluoride exposure group (10.0 mg/L fluorine),and high fluoride exposure group (50.0 mg/L fluoride).The experiment period was 6 months.The protein level of PKCβ,p66shc,phospho-p66shc and preserved ammonia acyl isomerase (Pin1) in rat brain was detected by Western blotting.The level of neuron nuclear antigen (NeuN),p66shc and phospho-p66sh in brain of rats was detected by immunohistochemistry.Results By Western blotting,the levels of PKCβ,Pin1 and phospho-p66shc protein in brain tissue in high fluoride exposure group [(193.00 ± 57.53)％,(228.21 ± 71.14)％,(201.54 ±:50.86)％] were higher than those of the normal control groups [(100.00 ± 21.24)％,(100.00 ± 40.55)％,(100.00 ± 13.35)％,all P ＜ 0.05].By immunohistochemistry,the numbers of NeuN staining in brain tissue of the rats in both high and low fluoride exposure groups [(49.50 ± 12.57)％,(65.66 ±14.58)％] were lower than that of the control group [(100.00 ± 18.32)％,all P ＜ 0.01].The level of phospho-p66shc protein in brain tissue in high fluoride exposure group [(242.66 ± 93.01)％] was higher than those of the low fluoride exposure and the normal control groups [(152.53 ± 60.65)％,(100.00 ± 25.63)％,all P ＜ 0.01].Conclusion Chronic fluorosis has increased the expressions of PKCβ,Pin1 and phospho-p66shc at protein level in brain of rats,which may be related to the molecular mechanism of brain damage resulted from chronic fluorosis.

Objective To investigate the expression of the preferentially expressed antigen of melanoma (PRAME) gene in acute myeloid leukemia (AML),and to evaluate its applicability in monitoring minimal residual disease (MRD).Methods Bone marrow specimens were collected from 63 cases of de-novo AML,while 34 samples from 11 patients were tracked for 28 months.The level of PRAME mRNA was measured by real time RT-PCR.Results The PRAME gene expressed in 52.4 ％ (33/63) of de-novo patients,and the positive rate was highest in M3 than that in other subtypes of AML.The expression of PRAME became negative after treatment and increased in the following months before morphology relapse.Conclusion The PRAME gene is highly expressed in AML and could be a useful marker to monitor MRD.

Objective:To investigate the efficacy and toxicity of oxaliplatin reintroduction combined with raltitrexed as second-line che-motherapy after the first-line oxaliplatin-based chemotherapy in advanced colorectal cancer patients. Methods:The 48 evaluable pa-tients with advanced colorectal cancer following disease progression prior to the first-line chemotherapy were treated with oxaliplatin and raltitrexed (raltitrexed 3 mg/m2 ivgtt d1, oxaliplatin 100-130 mg/m2 ivgtt d1, q21d). All 48 patients were divided into two groups:Group A, non-oxaliplatin-based regimens as the first-line chemotherapy, 20 cases;Group B, oxaliplatin-based regimens as the first-line chemotherapy, 28 cases. Each group was evaluated every two cycles. Results:The response rates (RR) of Groups A and B were 30.0%(6/20) and 32.1%(9/28), the disease control rates (DCR) were 80.0%(16/20) and 75.0%(21/28), the median progression free survival time (mPFS) was 6.5 and 7.0 months, and the median overall survival time (mOS) was 10 and 13 months, respectively. No statistical sig-nificance was observed between the two groups in their RR, CR, mPFS, and mOS (P=0.264, 0.514, 0.713, 0.788), respectively. The most common adverse effects observed wereⅠ-Ⅱgrades of bone marrow suppression, aminotransferase abnormality, and digestive toxici-ties. The incidence of neurotoxicity (Ⅰ-Ⅱgrades) between the two groups was similar. Conclusion:Instead of irinotecan combined with raltitrexed, oxaliplatin reintroduction combined with raltitrexed for second-line chemotherapy after the first-line oxaliplatin-based chemotherapy in advanced colorectal cancer patients is feasible.