ABSTRACT: Acute liver injury (ALI) is an important medical problem that requires effective therapy. Astaxanthin (AST) is a carotenoid, and the beneficial effects of astaxanthin, including anti-oxidative, anti-inflammatory and anti-tumour activities, have been identified. The present study was designed to elucidate the protective effects of astaxanthin against ALI and their underlying mechanisms. RAW264.7 macrophages were treated with dimethyl sulfoxide combined with different doses of astaxanthin for 12 h. Mice were fed with or without astaxanthin for up to 7 days. LPS was administered to induce inflammation. We assessed histopathology, oxidative stress, inflammation and apoptosis .The results indicated that astaxanthin attenuated LPS-induced oxidative stress, inflammation and cell apoptosis both in vivo and in vitro. In vivo and in vitro experiments showed that astaxanthin down regulated the nuclear factor-kappa beta (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2) and NLR family pyrin domain containing 3 (NLRP3) signalling pathways, inhibiting the LPS-induced inflammatory response, oxidative stress and cell apoptosis, and alleviating LPS-induced ALI in mice.

RESUMO: A lesão hepática aguda (ALI) é um problema médico importante que requer terapia eficaz. A astaxantina (AST) é um carotenóide, e os efeitos benéficos da astaxantina, incluindo atividades antioxidantes, anti-inflamatórias e antitumorais, foram identificados. O presente estudo foi desenhado para elucidar os efeitos protetores da astaxantina contra ALI e seus mecanismos subjacentes. Macrófagos RAW264.7 foram tratados com dimetil sulfóxido combinado com diferentes doses de astaxantina por 12 h. Os camundongos foram alimentados com ou sem astaxantina por até sete dias. O LPS foi administrado para induzir a inflamação. Histopatologia, estresse oxidativo, inflamação e apoptose foram avaliados. Os resultados indicaram que a astaxantina atenuou o estresse oxidativo induzido por LPS, inflamação e apoptose celular in vivo e in vitro. Experimentos in vivo e in vitro mostraram que a astaxantina regulou negativamente as vias de sinalização do fator nuclear-kappa beta (NF-κB), fator nuclear 2 relacionado ao eritróide 2 (Nrf2) e domínio de pirina da família NLR contendo 3 (NLRP3), inibindo o LPS- resposta inflamatória induzida, estresse oxidativo e apoptose celular e alívio da ALI induzida por LPS em camundongos.

Resumo Fundamento: Estudos epidemiológicos recentes demonstraram que alterações na microbiota e seus metabólitos estão associadas à hipertensão arterial sistêmica. A Helicobacter pylori (H. pylori) é um dos patógenos bacterianos mais comuns, e a possível associação entre a infecção por H. pylori e a hipertensão é controversa. Objetivos: Este estudo teve o objetivo de esclarecer a associação entre eles e proporcionar uma nova base teórica para detectar a patogênese da hipertensão. Métodos: Foram selecionados estudos caso-controle e transversais sobre a associação entre H. pylori e hipertensão, publicados de 1996 a 2019 indexados nos bancos de dados PubMed, Google Scholar, Chinese Wan Fang Data, e Chinese National Knowledge Infrastructure (CNKI). As razões de chance (RC) combinadas e o intervalo de confiança (IC) 95% foram estimados. O I² foi realizado para avaliar a heterogeneidade estatística. O viés de publicação foi avaliado utilizando-se os testes de Beggs e de Egger. Os dados extraídos foram analisados no software Stata 12.0. A significância estatística foi definida com um p-valor < 0,05. Resultados: Foram cadastrados 17 estudos envolvendo 6376 casos de hipertensão e 10850 controles. A taxa de infecção por H. pylori em pacientes hipertensos e em controles foi de 64,9% e 56,3%, respectivamente. Foi demonstrada uma associação significativamente positiva entre a infecção por H. pylori e a hipertensão, com uma RC global de 2,07 (IC 95%: 1,46–2,94; p < 0,05). A análise de subgrupos revelou que a prevalência de infecção por H. pylori foi associada à hipertensão na região da Ásia e no grupo de caso-controle, as RC (IC 95%) foram 2,26 (1,51-3,38) e 2,53 (1,72-3,72), respectivamente. Depois de estratificar por métodos de detecção, ainda existiam diferenças entre os subgrupos (todos p < 0,05). Conclusão: Esta metanálise indicou que a infecção por H. pylori está associada positivamente à hipertensão.

Abstract Background: Recent epidemiological studies have shown that alterations in microbiota and its metabolites are associated with systemic arterial hypertension. Helicobacter pylori (H. pylori) is one of the most common bacterial pathogens, and the potential association between H. pylori infection and hypertension are controversial. Objective: This study aimed to clarify their association and provide a new theoretical basis for uncovering the pathogenesis of hypertension. Methods: Case-control and cross-sectional studies on the association between H. pylori and hypertension published from 1996 to 2019 indexed in PubMed, Google Scholar, Chinese Wan Fang Data, and Chinese National Knowledge Infrastructure (CNKI). The pooled odds ratios (OR) and 95% confidence interval (CI) were estimated. I2 was performed to evaluate the statistical heterogeneity. Publication bias was evaluated using Begg’s and Egger’s test. The extracted data was analyzed in Stata 12.0. Statistical significance was defined as p-value < 0.05. Results: A total of 17 studies involving 6,376 cases of hypertension and 10,850 controls were enrolled. H. pylori infection rate in hypertension patients and controls were 64.9% and 56.3%, respectively. A significantly positive association was shown between H. pylori infection and hypertension with an overall OR of 2.07 (95% CI: 1.46–2.94; p < 0.05). Subgroup analysis revealed that the prevalence of H. pylori infection was associated with hypertension in the region of Asia and the case-control group, ORs (95% CI) were 2.26 (1.51-3.38) and 2.53 (1.72-3.72), respectively. After stratifying by detection methods, differences still existed in subgroups (all p < 0.05). Conclusion: This meta-analysis indicated that H. pylori infection is positively associated with hypertension.

Resumo Objetivo: Comparar o valor preditivo negativo (VPN) da RM multiparamétrica da próstata para o diagnóstico de tumores escore de Gleason (EG) ≥ 3+4 e avaliar os preditores desses tumores em homens com suspeita de doença e nos sob vigilância ativa (VA). Materiais e Métodos: Este estudo retrospectivo incluiu 38 homens com suspeita de câncer de próstata e 38 em VA com RM, aos quais foram atribuídos escores PI-RADS v2 1 ou 2 entre maio de 2016 e setembro de 2017. Os resultados da biópsia foram ausência de câncer, câncer EG = 3+3 ou câncer EG ≥ 3+4. PSA pré-RM, volume da glândula e densidade de PSA foram anotados. Qui-quadrado, igualdade de proporções e regressões logísticas foram utilizados para analisar os dados. Resultados: Câncer de grau intermediário a alto grau foi encontrado em 12,8% (IC 95% = 2,3-23,3) e 35,9% (IC 95% = 20,8-50,9) dos homens com suspeita de câncer e nos sob VA (p = 0,02), respectivamente. O VPN para GS ≥ 3+4 foi 87,2% (suspeita de câncer; IC 95% = 76,7-97,7) e 64,1% (VA; IC 95% = 49,0-79,2). Em nenhum dos grupos o PSA previu significativamente o grau de câncer (p = 0,75 e 0,63. Embora não tenha alcançado o limiar de significância estatística usual, a densidade de PSA foi um bom preditor de grau de câncer em homens com suspeita de doença (p = 0,06), mas não sob VA (p = 0,62). Conclusão: O VPN da RM multiparamétrica para GS ≥ 3+4 é maior em homens com suspeita de câncer de próstata do que em homens sob VA. Uma densidade de PSA ≤ 0,15 melhorou a previsão de doença de grau intermediário a alto grau em pacientes sem diagnóstico prévio de câncer.

Abstract Objective: To compare the negative predictive value (NPV) of multiparametric MRI for Gleason score (GS) ≥ 3+4 cancer and evaluate predictors of these tumors in men with suspected disease and under active surveillance (AS). Materials and Methods: This retrospective study included 38 men with suspected prostate cancer and 38 under AS with scans assigned PI-RADS v2 scores 1 or 2 between May 2016 and September 2017. Biopsy results were no cancer, GS = 3+3, or GS ≥ 3+4. Pre-MRI PSA, gland volume, and PSA density were recorded. Chi-square, equality of proportions, and logistic regressions were used to analyze the data. Results: Intermediate to high-grade cancer was found in 12.8% (95% CI = 2.3-23.3) and 35.9% (95% CI = 20.8-50.9) of men with suspected cancer, and under AS (p = 0.02), respectively. The NPV for GS ≥ 3+4 were 87.2% (suspected cancer; 76.7-97.7) and 64.1% (AS; 49.0-79.2). In neither group PSA significantly predicted cancer grade (p = 0.75 and 0.63). Although it did not reach conventional statistical significance, PSA density was a good predictor of cancer grade in men with suspected disease (p = 0.06), but not under AS (p = 0.62). Conclusion: The NPV of multiparametric MRI for GS ≥ 3+4 is higher in men with suspected prostate cancer than in men under AS. PSA density ≤ 0.15 improved the prediction of intermediate to high-grade disease in patients without known cancer.

Resumo Introdução: A lesão hepática por isquemia-reperfusão é um processo fisiopatológico comum em cirurgias hepáticas. Mais estudos ainda são necessários para avaliar se o propofol pode reduzir a lesão de isquemia-reperfusão miocárdica induzida pela lesão de isquemia-reperfusão hepática em ratos, juntamente com os mecanismos que estão relacionados. Objetivo: Investigar se propofol protege as células do miocárdio da apoptose com a lesão hepática por isquemia-reperfusão. Métodos: Ratos machos da raça Sprague-Dawley (n = 18) foram alocados aleatoriamente em três grupos: Grupo Sham (Grupo S, n = 6), Grupo Lesão Hepática por Isquemia-reperfusão (Grupo IR, n = 6) e Grupo Propofol (Grupo P, n = 6). O Grupo S foi submetido apenas à laparotomia. O grupo IR foi submetido à isquemia por 30 min e reperfusão por 4 h. O grupo P foi submetido à mesma isquemia do grupo IR, com a administração de 120 mg.kg-1 de propofol iniciada 10min antes da isquemia, seguida de infusão contínua a 20 mg.kg-1.h-1. A apoptose celular foi examinada por meio do ensaio de marcação de terminações dUTP pela deoxinucleotidil transferase. Retículo endoplasmático Ca2+-ATPase2 (SERCA2) e caspase-3 do ácido aspártico contendo cisteína (caspase-3 clivada) foram avaliados com o ensaio western blot e reação em cadeia da polimerase. Resultados: A taxa de apoptose foi maior com mRNA e proteína de SERCA2 regulados para baixo e caspase-3 clivada suprarregulada no Grupo IR, em comparação com o Grupo S (p < 0,01). A taxa de apoptose foi menor com mRNA e proteína de SERCA2 suprarregulada e caspase-3 clivada sub-regulada no Grupo P, em comparação com o Grupo IR (p < 0,01). Conclusões: O propofol pode reduzir a apoptose de células miocárdicas induzida por lesão hepática por isquemia-reperfusão. Entretanto, pode suprarregular o mRNA e a proteína de SERCA2 em ratos.

Abstract Introduction: Hepatic ischemia-reperfusion injury is a common pathophysiological process in liver surgery. Whether Propofol can reduce myocardial ischemia-reperfusion injury induced by hepatic ischemia-reperfusion injury in rats, together with related mechanisms, still needs further studies. Objective: To investigate if propofol would protect the myocardial cells from apoptosis with hepatic ischemia-reperfusion injury. Methods: Male Sprague-Dawley rats (n = 18) were randomly allocated into three groups: Sham Group (Group S, n = 6), Hepatic Ischemia-reperfusion Injury Group (Group IR, n = 6) and Propofol Group (Group P, n = 6). Group S was only subjected to laparotomy. Group IR was attained by ischemia for 30 min and reperfusion for 4 h. Group P was subjected identical insult as in Group IR with the administration of propofol started 10 min before ischemia with 120 mg.kg−1, following by continuous infusion at 20 mg.kg−1.h−1. Cell apoptosis was examined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. Endoplasmic reticulum Ca2+-ATPase2 (SERCA2) and cysteine-containing aspartic acid cleaved-caspase3 (cleaved-caspase3) were assayed by western blot and Altimeter polymerase chain reaction. Results: Apoptosis rate was increased, with mRNA and protein of SERCA2 down-regulated and cleaved-caspase3 up-regulated in Group IR compared with Group S (p < 0.01). Apoptosis rate was decreased, with mRNA and protein of SERCA2 up-regulated and cleaved-caspase3 down-regulated in Group P compared with Group IR (p < 0.01). Conclusions: Propofol can reduce hepatic ischemia-reperfusion injury-induced myocardial cell apoptosis, meanwhile, can up-regulate mRNA and protein of SERCA2 in rats.

RESUMO Devido ao aquecimento global, em Seul na Coreia do Sul, é plausível plantar árvores de folhagem perenes no inverno frio, oferecendo opções para criar um ambiente verde. Assim, é válido investigar quais tipos de plantas de folhagem perene poderiam sobreviver em Seul durante o inverno. Neste estudo, escolheu-se a hera-inglesa (Hedera helix), planta nativa da Europa utilizada como ornamental. Ela cresce em condições de temperaturas moderadas. Neste trabalho, investigou-se H. helix, uma planta de cobertura perene ao longo do inverno, a fim de avaliar a possibilidade de utilizar esta espécie em Seul. Descobriu-se que H. helix pode sobreviver durante o inverno em Seul. Isso significa que ela pode ser utilizada para criar um ambiente perene em Seul. Isto também implica que similares tipos de plantas poderiam ser testados assumindo que o ambiente em Seul está se tornando mais adequado para as plantas originadas de lugares quentes. Isto nos proverá maiores opções para elaborar ambientes ao ar livre na cidade que não é tão arborizada.

ABSTRACT Due to the global warming, Seoul in Korea seems to be plausible to grow evergreen broad-leaved trees over the cold winter. This offers the planting options to create green environment. Thus, it became worth investigating what kinds of evergreen broad-leaved plants could stand in Seoul during the winter. Ivy (Hedera helix) has been chosen in the current study which is a well-known native and ornamental plant in Europe. It grows in warm condition in general. The current study tracked H. helix which is evergreen cover plant over winter in order to evaluate the possibility for utilizing this species as a climber or cover-plant in Seoul. We found that H. helix can survive over the winter and can be utilized to create evergreen environment in Seoul. It also implies that similar kinds of plants could be tested assuming the environment of Seoul is becoming more suitable for the plants originated from the warmer sites. H. helix is an option for elaborating outdoor environments in the city that lacks of green color.

Abstract The severity of Helicobacter pylori-related disease is correlated with the presence and integrity of a cag pathogenicity island (cagPAI). cagPAI genotype may have a modifying effect on the pathogenic potential of the infecting strain. After analyzing the sequences of cagPAI genes, some strains with the East Asian-type cagPAI genes were selected for further analysis to examine the association between the diversity of the cagPAI genes and the virulence of H. pylori. The results showed that gastric mucosal inflammatory cell infiltration was significantly higher in patients with East Asian-type cagPAI genes H. pylori strain compared with mosaicism cagPAI genes H. pylori strain (p < 0.05). H. pylori strains with the East Asian-type cagPAI genes were closely associated with IL-8 secretion in vitro and in vivo compared with H. pylori strains with the mosaicism cagPAI genes (p < 0.01). H. pylori strains with East Asian-type cagPAI genes are able to strongly translocate CagA to host cells. These results suggest that H. pylori strains with East Asian-type cagPAI genes are more virulent than the strains of cagPAI gene/genes that are Western type.

During endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), a needle is commonly used with a stylet, although recently the stylet has been omitted. This prospective study aimed to compare the quality of specimens obtained by EBUS-TBNA performed with and without a stylet. Between November 2013 and November 2014, 131 patients with lung cancer underwent EBUS-TBNA, with a total of 148 mediastinal or hilar lymph nodes sampled both with and without an inner-stylet, yielding 296 cytological specimens. Specimens were scored cytologically using five parameters: background blood or clot, amount of cellular material, degree of cellular degeneration, degree of cellular trauma, and retention of appropriate architecture. The procedure with a stylet required significantly longer operation time than without a stylet (14.5±0.8 vs 12.7±1.1 min, P<0.001). Excellent specimens were obtained in 261/296 and 260/296 samples in the procedures with and without a stylet, respectively (P=0.9), while the remaining 35 and 36 samples, respectively, were adequate. The diagnosing and staging of lung cancer using EBUS-TBNA did not differ significantly between the groups. In conclusion, specimen collection by EBUS-TBNA without a stylet is easier and faster than the procedure using a stylet and absence of a stylet did not alter specimen quality or diagnostic accuracy.

Contact force (CF) sensing technology allows real-time monitoring during catheter ablation for atrial fibrillation (AF). However, the effect of CF sensing technology on procedural parameters and clinical outcomes still needs clarification. Because of the inconsistent results thus far in this area, we performed a meta-analysis to determine whether CF sensing technology can improve procedural parameters and clinical outcomes for the treatment of AF. Studies examining the benefits of CF sensing technology were identified in English-language articles by searching the MEDLINE, Web of Science, and Cochrane Library databases (inception to May 2015). Ten randomized, controlled trials involving 1834 patients (1263 males, 571 females) were included in the meta-analysis (681 in the CF group, 1153 in the control group). Overall, the ablation time was significantly decreased by 7.34 min (95%CI=-12.21 to -2.46; P=0.003, Z test) in the CF group compared with the control group. CF sensing technology was associated with significantly improved freedom from AF after 12 months (OR=1.55, 95%CI=1.20 to 1.99; P=0.0007) and complications were significantly lower in the CF group than in the control group (OR=0.50, 95%CI=0.29 to 0.87; P=0.01). However, fluoroscopy time analysis showed no significantly decreased trend associated with CF-guided catheter ablation (weighted mean difference: -2.59; 95%CI=-9.06 to 3.88; P=0.43). The present meta-analysis shows improvement in ablation time and freedom from AF after 12 months in AF patients treated with CF-guided catheter ablation. However, CF-guided catheter ablation does not decrease fluoroscopy time.

High plasma levels of homocysteine (Hcy) promote the progression of neurodegenerative diseases. However, the mechanism by which Hcy mediates neurotoxicity has not been elucidated. We observed that upon incubation with Hcy, the viability of a neuroblastoma cell line Neuro2a declined in a dose-dependent manner, and apoptosis was induced within 48 h. The median effective concentration (EC50) of Hcy was approximately 5 mM. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) nuclear translocation and acylation has been implicated in the regulation of apoptosis. We found that nuclear translocation and acetylation of GAPDH increased in the presence of 5 mM Hcy and that higher levels of acetyltransferase p300/CBP were detected in Neuro2a cells. These findings implicate the involvement of GAPDH in the mechanism whereby Hcy induces apoptosis in neurons. This study highlights a potentially important pathway in neurodegenerative disorders, and a novel target pathway for neuroprotective therapy.

OBJECTIVES: The eradication of Helicobacter (H.) pylori allows peptic ulcers in patients infected with the bacteria to be cured. Treatment with the classic triple regimen (proton pump inhibitor, amoxicillin and clarithromycin) has shown decreased efficacy due to increased bacterial resistance to clarithromycin. In our country, the eradication rate by intention to treat with this regimen is 83%. In Brazil, a commercially available regimen for bacterial eradication that uses levofloxacin and amoxicillin with lansoprazole is available; however, its efficacy is not known. Considering that such a treatment may be an alternative to the classic regimen, we aimed to verify its efficacy in H. pylori eradication. METHODS: Patients with peptic ulcer disease infected with H. pylori who had not received prior treatment were treated with the following regimen: 30 mg lansoprazole bid, 1,000 mg amoxicillin bid and 500 mg levofloxacin, once a day for 7 days. RESULTS: A total of 66 patients were evaluated. The patients’ mean age was 52 years, and women comprised 55% of the sample. Duodenal ulcers were present in 50% of cases, and gastric ulcers were present in 30%. The eradication rate was 74% per protocol and 73% by intention to treat. Adverse effects were reported by 49 patients (74%) and were mild to moderate, with a prevalence of diarrhea complaints. CONCLUSIONS: Triple therapy comprising lansoprazole, amoxicillin and levofloxacin for 7 days for the eradication of H. pylori in Brazilian peptic ulcer patients showed a lower efficacy than that of the classic triple regimen.

Acute cerebral hemorrhage (ACH) is an important clinical problem that is often monitored and studied with expensive devices such as computed tomography, magnetic resonance imaging, and positron emission tomography. These devices are not readily available in economically underdeveloped regions of the world, emergency departments, and emergency zones. We have developed a less expensive tool for non-contact monitoring of ACH. The system measures the magnetic induction phase shift (MIPS) between the electromagnetic signals on two coils. ACH was induced in 6 experimental rabbits and edema was induced in 4 control rabbits by stereotactic methods, and their intracranial pressure and heart rate were monitored for 1 h. Signals were continuously monitored for up to 1 h at an exciting frequency of 10.7 MHz. Autologous blood was administered to the experimental group, and saline to the control group (1 to 3 mL) by injection of 1-mL every 5 min. The results showed a significant increase in MIPS as a function of the injection volume, but the heart rate was stable. In the experimental (ACH) group, there was a statistically significant positive correlation of the intracranial pressure and MIPS. The change of MIPS was greater in the ACH group than in the control group. This high-sensitivity system could detect a 1-mL change in blood volume. The MIPS was significantly related to the intracranial pressure. This observation suggests that the method could be valuable for detecting early warning signs in emergency medicine and critical care units.

A composição e atividade antimicrobiana dos óleos essenciais obtidos de madeira de ágar originária de Aquilaria sinensis (Lour.) Gilg induzido por agente biológico da madeira de ágar, Lasiodiplodia theobromae (F), foram caracterizadas e comparadas com madeira de ágar selvagem (W) e árvores saudáveis não inoculadas (H) como controles positivo e negativo, respectivamente. A composição química de F foi investigada usando cromatografia gasosa-espectrometria de massas (GC-MS). O óleo essencial de F mostrou uma composição similar de W, sendo rico em sesquiterpenos e constituintes aromáticos. No entanto, o óleo essencial de H era abundante em alcanos. Os óleos essenciais de F e W mostraram ser inibidores mais potentes de L. theobromae, Fusariumoxysporum, e Candida albicans do que o óleo essencial de H. Nossas descobertas demonstram pela primeira vez que o óleo essencial obtido da madeira de ágar originado de A. sinensis induzido por L. theobromae teve uma alta similaridade com o óleo essencial da madeira de ágar selvagem, tanto em composição química como em atividade antimicrobiana. Além disso, a estratégia de madeira de ágar induzida por fungos pode ser potencialmente aplicada em madeira de ágar e produção de óleo essencial em árvores do gênero Aquilaria.

The composition and antimicrobial activity of essential oils obtained from agarwood originating from Aquilaria sinensis (Lour.) Gilg induced by a biological agent of agarwood, Lasiodiplodia theobromae (F), were characterized and compared to those from wild agarwood (W) and uninoculated healthy trees (H) as positive and negative control, respectively. The chemical composition of F was investigated using gas chromatography-mass spectrometry (GC-MS). The essential oil of F showed a similar composition to that of W, being rich in sesquiterpenes and aromatic constituents. However, the essential oil of H was abundant in alkanes. Essential oils of F and W were more potent inhibitors of L. theobromae, Fusarium oxysporum, and Candida albicans than the essential oil of H. Our findings demonstrate for the first time that the essential oil obtained from the agarwood originating from A. sinensis induced by L. theobromae had a high similarity to that of the essential oil of wild agarwood, both in chemical composition and in antimicrobial activity. Furthermore, the strategy of agarwood induced by fungi could be potentially applied in agarwood and essential oil production in Aquilaria trees.

Ziyuglycoside II is an active compound of Sanguisorba officinalis L. that has anti-inflammation, antioxidation, antibiosis, and homeostasis properties. We report here on the anticancer effect of ziyuglycoside II on human gastric carcinoma BGC-823 cells. We investigated the effects of ziyuglycoside II on cell growth, cell cycle, and cell apoptosis of this cell line. Our results revealed that ziyuglycoside II could inhibit the proliferation of BGC-823 cells by inducing apoptosis but not cell cycle arrest, which was associated with regulation of Bax/Bcl-2 expression, and activation of the caspase-3 pathway. Our study is the first to report the antitumor potential of ziyuglycoside II in BGC-823 gastric cancer cells. Ziyuglycoside II may become a potential therapeutic agent against gastric cancer in the future.

Carrying out regression analysis for gas leakage of pressure-relief valve (PRV) to get accurate leakage flow and changing trend of leakage will be helpful in assessing the reliability of PRV. Classic support vector regression (SVR) is an excellent regression model, and has been widely used in various fields. However, standard SVR model does regression only using leakage data without elements closely related to the leakage considered. In this paper a regression model based on support vector regression plus (SVR+) is put forward to perform leakage regression of PRV, in which particle swarm optimization (PSO) is used to select optimum parameters of SVR+, termed PSO_SVR+. The experimental results demonstrate that the proposed model taking the difference of inlet pressure and outlet pressure of PRV as hidden information can access a more favorable regression precision than SVR can provide. Meanwhile this article also investigates effects of PSO and Genetic Algorithm on the performance of regression model (SVR+ or SVR)