Long Non-Coding RNA Differentiation Antagonizing Nonprotein Coding RNA (DANCR) Promotes Proliferation and Invasion of Pancreatic Cancer by Sponging miR-214-5p to Regulate E2F2 Expression.

BACKGROUND Long non-coding RNA differentiation antagonizing nonprotein coding RNA (lncRNA DANCR) has been reported to act as an oncogene in various human cancers. The role of DANCR in development of pancreatic cancer (PC) is unknown. The aim of our research was to investigate the biological role of DANCR in PC. MATERIAL AND METHODS Expressions of DANCR, miR-214-5p, and E2F2 mRNA in PC tissues and cell lines were examined by qRT-PCR. Western blotting was carried out for detection of E2F2 protein expression in PC cells. Transwell assays were used to examine the metastatic ability of PC cells, while CCK-8 and colony formation assay were applied to evaluate cell proliferation. The effects of DANCR on PC cells were assessed by knockdown in vitro and in vivo. The regulatory mechanism of competitive endogenous RNAs were obtained from bioinformatics prediction and luciferase reporter assay. RESULTS DANCR was markedly upregulated in clinical tissues and cell lines of PC. High DANCR expression exhibited a significant correlation with poor prognosis. DANCR knockdown inhibited growth and metastasis of PC cells. Furthermore, DANCR acted as sponge to regulate miR-214-5p, and miR-214-5p inhibitor reversed the effects of DANCR knockdown on PC cells. Moreover, DANCR positively modulated E2F2 expression through miR-214-5p in PC cells. CONCLUSIONS Collectively, our findings demonstrated that lncRNA DANCR/miR-214-5p/E2F2 axis acts as an oncogene in PC development, which might provide a potential target for PC therapy.

Valproate Attenuates Endoplasmic Reticulum Stress-Induced Apoptosis in SH-SY5Y Cells via the AKT/GSK3ß Signaling Pathway.

Endoplasmic reticulum (ER) stress-induced apoptosis plays an important role in a range of neurological disorders, such as neurodegenerative diseases, spinal cord injury, and diabetic neuropathy. Valproate (VPA), a typical antiepileptic drug, is commonly used in the treatment of bipolar disorder and epilepsy. Recently, VPA has been reported to exert neurotrophic effects and promote neurite outgrowth, but its molecular mechanism is still unclear. In the present study, we investigated whether VPA inhibited ER stress and promoted neuroprotection and neuronal restoration in SH-SY5Y cells and in primary rat cortical neurons, respectively, upon exposure to thapsigargin (TG). In SH-SY5Y cells, cell viability was detected by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, and the expression of ER stress-related apoptotic proteins such as glucose­regulated protein (GRP78), C/EBP homologous protein (CHOP), and cleaved caspase-12/-3 were analyzed with Western blot analyses and immunofluorescence assays. To explore the pathway involved in VPA-induced cell proliferation, we also examined p-AKT, GSK3ß, p-JNK and MMP-9. Moreover, to detect the effect of VPA in primary cortical neurons, immunofluorescence staining of ß-III tubulin and Anti-NeuN was analyzed in primary cultured neurons exposed to TG. Our results demonstrated that VPA administration improved cell viability in cells exposed to TG. In addition, VPA increased the levels of GRP78 and p-AKT and decreased the levels of ATF6, XBP-1, GSK3ß, p-JNK and MMP-9. Furthermore, the levels of the ER stress-induced apoptosis response proteins CHOP, cleaved caspase-12 and cleaved caspase-3 were inhibited by VPA treatment. Meanwhile, VPA administration also increased the ratio of Bcl-2/Bax. Moreover, VPA can maintain neurite outgrowth of primary cortical neurons. Collectively, the neurotrophic effect of VPA is related to the inhibition of ER stress-induced apoptosis in SH-SY5Y cells and the maintenance of neuronal growth. Collectively, our results suggested a new approach for the therapeutic function of VPA in neurological disorders and neuroprotection.

[Analysis of Antibodies with Superior Antigen-recognition in Serum from Patients Infected by Necator americanus].

Objective: To evaluate the reactivity of adult hookworm antigens to serum from patients with hookworm disease, and analyze in the serum class- or subclass-specific antibodies that show superior antigen recognition. Methods: Sera from healthy participants, patients infected by Necator americanus and those with other parasitic infections were processed for ELISA, which used raw antigens extracted from adult worms of Necator americanus as the coating antigen, and different classes or subclasses of anti-human antibody labeled with HRP as the secondary antibody. The sensitivity and specificity of the assay with various secondary antibodies were compared. Results: The ELISA using IgM, IgD，IgE, IgG, IgG1, IgG2, IgG3, or IgG4 as the secondary antibody showed a sensitivity of 41.84%, 2.04%, 1.02%, 92.93%, 19.39%, 25.51%, 17.35%, and 88.78%, respectively; specificity of 77.61% 97.01%, 92.54%, 79.10%, 95.52%, 92.53%, 92.53%, and 92.53%, respectively; and diagnostic efficiency of 56.36%, 40.61%, 38.18%, 87.88%, 50.30%, 52.7%, 47.88%, and 90.30%, respectively. The sensitivity when using IgG4 and IgG as the secondary antibody had far exceeded that when using IgM, IgD, IgE, and other three subclasses of IgG (P<0.05). There was no difference in sensitivity between tests using IgG4 and IgG (χ2=1.61, P＞0.05). However, the test using IgG4 revealed significantly higher specificity than that using IgG (χ2=4.97, P＜0.05). Conclusion: Use of IgG4 as the enzyme-linked secondary antibody shows advantages in overall diagnostic efficiency over other classes/subclasses in ELISA.

Event-triggered H∞ control for discrete-time switched systems with saturation nonlinearities.

This paper studies the event-triggered H∞ control based on the average dwell time (ADT) method for discrete-time switched system with input saturation and state saturation. Based on the convex hull method, the state feedback controller and the dynamic output feedback controller are designed respectively. The influence of input saturation and state saturation on the dynamic performance of the system is eliminated. The dynamic event-triggered mechanism is introduced, which saves the communication resources and computation resources of the system. Based on ADT, the H∞ exponential stability of the closed-loop system is guaranteed.Finally, the effectiveness of the proposed method is verified by the numerical examples.

Differential diagnosis of cystic and alveolar echinococcosis using an immunochromatographic test based on the detection of specific antibodies.

Human cystic and alveolar echinococcoses are zoonotic diseases caused by the larval stages of Echinococcus granulosus and Echinococcus multilocularis, respectively. As the diseases are co-endemic in many areas of the world, a simple and rapid test for the differential diagnosis of cystic echinococcosis (CE) and alveolar echinocoocosis (AE) is needed. Here, we describe the development of an immunochromatographic test (ICT) using crude hydatid cyst fluid and a recombinant 18-kDa protein (rEm18) as antigens for the detection of E. granulosus and E. multilocularis antibodies in serum samples. The ICT was evaluated with serum samples from 195 echinococcosis patients from different endemic areas in northwestern China. These included 144 from CE patients, 51 from AE patients, 67 from patients with other parasitic diseases, 13 from patients with serous hepatic cysts, and 60 from healthy individuals. The sensitivity and specificity of the ICT for CE were 91.0 and 96.9% and for AE were 98.0 and 99.3% with diagnostic efficiencies of 94.1 and 99.1%, respectively. No significant differences and high degrees of agreement were found between the ICT and an enzyme-linked immunosorbent assay for both CE and AE. Five serum samples from cysticercosis patients and one serum sample from a healthy control were found positive for CE with the ICT. These findings indicate that this test allows for discrimination between both forms of human echinococcosis. In conclusion, the ICT developed in this study is a promising tool for the simultaneous detection and discrimination of CE and AE. This test will be useful for serodiagnosis of CE and AE in clinical settings and screening programs.

[Establishment and evaluation of colloid gold labeled immunochromatographic strip test for rapid diagnosis of alveolar echinococcosis].

OBJECTIVE: To establish and evaluate a colloid gold immunochromatographic strip test for the diagnosis of alveolar echinococcosis. METHODS: Total RNA was prepared from Echinococcus multilocularis protoscoleces collected from Xinjiang Uygur Autonomous Region. Em18 gene was obtained by reverse transcription-polymerase chain reaction (RT-PCR). The PCR product was sequenced and cloned into pGEX-3X vector. The recombinant plasmid was expressed and induced by isopropyl-beta-D-thiogalactopyranoside (IPTG) to obtain recombinant protein. The anti-human IgG monoclonal antibodies was conjugated with colloid gold as detecting reagent; the recombinant Em18 antigen and goat anti-mouse IgG were immobilized on nitrocellulose in proper position. The prepared immunochromatographic strip was evaluated using serum samples from patients with alveolar echinococcosis (56), cystic echinococcosis (87), cysticercosis (30), schistosomiasis japonica (10), toxoplasmosis (10) and healthy subjects (50) . Comparison between the immunochromatographic strip test and ELISA was made by kappa statistics. RESULTS: Sensitivity detected by the immunochromatographic strip test was 92.9% (52/56). The cross-reactivity to cystic echinococcosis and cysticercosis was 9.2% (8/87) and 3.3% (1/30), respectively. There was no cross reactivity with schistosomiasis japonica and toxoplasmosis. 4 samples out of 50 healthy people showed false positive reaction. The overall specificity was 93.0 (174/187). Sensitivity and specificity both showed no statistical difference between immunochromatographic strip test and ELISA. High degree of agreement was observed between the strip test and ELISA (kappa = 0.98). CONCLUSION: The developed immunochromatographic strip test using recombinant Em18 antigen as coated antigen is a sensitive, specific, simple and rapid assay for diagnosing alveolar echinococcosis.

The complete mitochondrial genome of Xenopsylla cheopis (Siphonaptera: Pulicidae).

Xenopsylla cheopis, also called oriental rat flea, is an ectoparasite as well as disease vector for murine typhus and bubonic plague. In the study, the whole mitochondrial genome of X. cheopis was sequenced and assembled, which is the second report of mitochondrial genome in the family Pulicidae and the sixth mitochondrial genome in the order Siphonaptera (fleas). The mitochondrial genome is 18,902 bp in length, consisting of 40% A, 44% T, 6% G, and 10% C. Phylogenetic analysis of all available mitochondrial genomes from Siphonaptera indicated that X. cheopis clustered with Ctenocephalides felis since both species belonged to the family Pulicidae. The complete mitochondrial genome of X. cheopis could serve as useful genetic data for investigating the genetic relationship of fleas.

[Detection and species identification of two imported cases of cutaneous leishmaniasis].

OBJECTIVE: To diagnose and identify pathogen of two suspected cases of cutaneous leishmaniasis. METHODS: Two cases of dermatosis with several major ulcers on the skin were examined, who worked and returned from Algeria (case 1) and Saudi Arabia (case 2), respectively. The stained smears of skin tissue from lesions were observed by microscope. Extravasate from lesions was cultured in NNN medium to search protozoan parasites, which were obtained by centrifugation. Two pairs of species-specific primers, ITS1-ITS2 and K13A-K13B, were used to amplify inter-nal transcribed spacer of rDNA and kinetoplast DNA, respectively. The products were sequenced and analyzed by Blast. RESULTS: There were Leishmania amastigotes in the tissue smear of case 2, while none in that of case 1. Promastigotes were found in culture medium of both cases. The PCR products of ITS1-ITS2 and K13A-K13B from 2 cases were about 330 bp and 120 bp with respective homology of 100% and 96% to corresponding sequences of Leishmania major. The accession numbers of 4 sequences were JF831924-JF831927. CONCLUSION: Two cases of dermatosis are diagnosed as imported cutaneous leishmaniasis and the pathogen is L. major.

Label-Free Quantitative Proteomic Analysis of Three Strains of Viscerotropic Leishmania Isolated from Patients with Different Epidemiological Types of Visceral Leishmaniasis in China.

BACKGROUND: There are three epidemiological types of visceral leishmaniasis in China, which are caused by Leishmania strains belonging to the L. donovani complex. The mechanisms underlying their differences in the population affected, disease latency, and animal host, etc., remain unclear. We investigated the protein abundance differences among Leishmania strains isolated from three types of visceral leishmaniasis endemic areas in China. METHODS: Promastigotes of the three Leishmania strains were cultured to the log phase and harvested. The protein tryptic digests were analyzed with liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS), followed by label-free quantitative analysis. The MS experiment was performed on a Q Exactive mass spectrometer. Raw spectra were quantitatively analyzed with the MaxQuant software (ver 1.3.0.5) and matched with the reference database. Differentially expressed proteins were analyzed using the bioinformatics method. The MS analysis was repeated three times for each sample. RESULTS: A total of 5012 proteins were identified across the KS-2, JIASHI-5 and SC6 strains in at least 2 of the three samples replicate. Of them, 1758 were identified to be differentially expressed at least between 2 strains, including 349 with known names. These differentially expressed proteins with known names are involved in biological functions such as energy and lipid metabolic process, nucleotide acid metabolic process, amino acid metabolic process, response to stress, cell membrane/cytoskeleton, cell cycle and proliferation, biological adhesion and proteolysis, localization and transport, regulation of the biological process, and signal transduction. CONCLUSION: The differentially expressed proteins and their related biological functions may shed light on the pathogenicity of Leishmania and targets for the development of vaccines and medicines.

A room-temperature ultrasonic hydrogen sensor based on a sensitive layer of reduced graphene oxide.

It is challenging to increase the sensitivity of a hydrogen sensor operating at room temperature due to weak sorption and tiny mass of hydrogen. In this work, an ultrasonic sensor is presented for detecting hydrogen, which is composed of a 128° YX-LiNbO3 substrate and a reduced graphene oxide (RGO) sensitive layer with a platinum catalyzer. By optimizing the depositing parameters of RGO and platinum, a considerably high sensitivity is achieved at room temperature. A frequency shift of 308.9 kHz is obtained in 100 ppm hydrogen mixed with argon, and a frequency shift of 24.4 kHz is obtained in 1000 ppm hydrogen mixed in synthetic air. It is demonstrated that in addition to strong sorption of the sensitive layer, the coaction of mass load and conductivity variation is key to high sensitivity of the sensor. By establishing the original conductivity of the sensitive layer within the "conductivity window" for enhancing electrical response, we improve the sensitivity of the ultrasonic sensor, which is available for detecting hydrogen with an extremely low concentration of 5 ppm.

Molecular characterization of Leishamania isolates from China by inter-simple sequence repeat polymerase chain reaction.

Leishmania has distinct epidemiological and biological characteristics and causes a variety of clinical symptoms. To understand the genetic diversity and the phylogenetic relationships among Leishmania isolates from China, 29 Leishmania isolates from different geographic origins, vectors, and hosts were analyzed using 21 inter-simple sequence repeat polymerase chain reaction (ISSR-PCR) primers. A total of 864 polymorphic bands were obtained. According to the results of the neighbor-joining phylogenetic tree and principal component analysis, the 29 isolates studied clustered into six groups. Isolates of Leishmania donovani complex from China share the highest similarity with the reference strain of L. donovani (DD8). This study helps to elucidate the genetic relationship among Leishmania isolates from China and similarities between Chinese isolates and World Health Organization reference strains. Furthermore, ISSR-PCR could also be a quick, simple, and reliable method for Leishmania species identification.

[Field evaluation of gold-immunochromatographic assay for diagnosis of vivax malaria].

OBJECTIVE: To evaluate a gold-immunochromatographic assay (GICA) for malaria diagnosis in an endemic area of vivax malaria. METHODS: Blood samples were collected from febrile patients in 5 township-hospitals of Mengcheng County, Anhui Province, between September and October 2008. The samples were examined by GICA and microscopy under double blind condition and the results were compared. RESULTS: Among 292 blood samples, 181 were found P. vivax-positive by microscopy, and 163 were positive by GICA. Altogether, the coincidence of the two methods stood for 92.8% (271/292), including 108 negatives and 163 positives. 21 samples with discrepancy covered 18 microscopy positive but GICA negative, 3 microscopy negative but GICA positive. The GICA positive rate in patients with a parasitaemia of > 1,000 parasites/microl, 100-1,000 parasites/microl, and < 100 parasites/microl was 93.5% (115/123), 86.0% (43/50), and 62.5% (5/8), respectively. CONCLUSION: GICA is a useful diagnosis method for endemic area of vivax malaria.

Role of the lipoxin A4 receptor in the development of neutrophil extracellular traps in Leishmania infantum infection.

BACKGROUND: Neutrophils play an immunomodulatory role through the release of neutrophil extracellular traps (NETs). NETs are released in response to Leishmania infection, but the mechanism of NET extrusion has not been elucidated. The lipoxin A4 receptor on neutrophils is crucial for the inflammatory response and immune regulation of many diseases, including Leishmania infection. Therefore, in the present study, we tried to explore whether Leishmania infantum promastigotes stimulate neutrophil activation and NET release via activating the lipoxin A4 receptor. RESULTS: Leishmania infantum promastigotes stimulated neutrophil activity, but blocking of the lipoxin A4 receptor with its antagonist Boc prior to L. infantum stimulation abrogated these effects. Neutrophils showed citrullinated histone H3 expression and simultaneous NET extrusion on L. infantum stimulation, but a decline in both was observed on blocking of the lipoxin A4 receptor. Moreover, differentiated HL-60 cells with lipoxin A4 receptor silencing showed a decrease in citrullinated histone H3 expression as compared to the unsilenced HL-60 samples on stimulation with promastigotes. CONCLUSIONS: Leishmania infantum promastigotes altered the characteristics of neutrophils and induced NET extrusion by activating the lipoxin A4 receptor. The lipoxin A4 receptor may have potential as a therapeutic target in relation to NET extrusion in the treatment of leishmaniasis, but its mechanisms of action need to be explored in more depth.

Listening to lanthanide complexes: determination of the intrinsic luminescence quantum yield by nonradiative relaxation.

The photophysical properties of lanthanide complexes have been studied extensively; however, fundamental parameters such as the intrinsic quantum yield as well as radiative and nonradiative decay rates are difficult or even impossible to measure experimentally. Herein, a photoacoustic (PA) method is proposed to determine the intrinsic quantum yield of lanthanide complexes with lifetimes in the order of milliseconds. This method is used to determine the intrinsic quantum yields for europium(III)-containing metallomesogens as well as terbium(III) complexes. The results show that the PA signal is sensitive to both the lifetime and the ratio of the fast-to-slow heat component of the samples. It is found that there is an efficient ligand sensitization and a moderate intrinsic quantum yield for the complexes. The intrinsic quantum yield of Eu(3+) in the metallomesogens exhibits an obvious increase upon the isotropic liquid to smectic A transition. The proposed PA method is quite simple, and can contribute to a clearer understanding of the photophysical processes in luminescent lanthanide complexes.

Pressure-induced phase transitions on a liquid crystalline europium(III) complex.

The effect of pressure on the phase behavior of the liquid crystalline complex [Eu(bta)(3)L(2)] (bta is benzoyltrifluoroacetonate, and L is the Schiff base 2-hydroxy-N-octadecyl-4-tetradecyloxybenzaldimine) was studied by X-ray diffraction, Raman spectroscopy, and luminescence spectroscopy. The pressure was varied between ambient pressure and 8.0 GPa. [Eu(bta)(3)L(2)] exhibits a smectic A (SmA) phase at room temperature. The complex undergoes a transition from the SmA phase to a solid lamellar structure around 0.22 GPa and another transition from the solid lamellar phase to an amorphous state from 1.6 to 3.5 GPa. At low pressures, the smectic layer spacing increases, and the intermolecular distance decreases. Above 3.5 GPa, both the interlamellar and the intermolecular spacings hardly change, but the intensity of X-ray reflections exhibits a remarkable decrease and eventually vanishes. An interpretation of the changes in the molecular structure is given. It was found that less interdigitation of the alkyl chains situated in adjacent layers and/or a full extension of the alkyl chains occurred at low pressures and that the second phase transition was accompanied by a transfer of the hydrogen atom from the nitrogen atom of the imine group to the oxygen atom of the Schiff base ligand. The effect of applying pressure equals that of the lanthanide contraction on the phase behavior.

[Study of lanthanide complexes-doped silica gels and the Co-fluorescence effect by photoacoustic spectroscopy in situ].

Silica matrices, due to their good optical, thermal and chemical properties, are suitable candidates for the hosts of luminescent lanthanide complexes. However, lanthanide complexes would be unstable in the most common sol-gel precursor solution. It is important to study the coordination environment of lanthanide ions and the formation of lanthanide complexes in silica gels. In the present work, lanthanide complexes Ln(Sal)3 x H2O(Ln3+:La3+, Nd3+ and Tb3+; Sal:salicylic acid) were incorporated into silica gels via a sol-gel process. PA technique was firstly used to monitor the formation of lanthanide complexes in silica gels. Upon heat treatment at 110 degrees C, PA intensity of the ligand increased for Tb3+, La3+ and Nd3+ complexes in silica gels, respectively, while this difference could not be observed for the wet gels (samples without heat treatment). By comparison with fluorescence spectra, experimental data indicate that lanthanide complexes decompose in wet gels. The formation of lanthanide complexes in silica gels is discussed from two aspects: radiative and nonradiative processes. Co-luminescence effect was found for lanthanide complexes with aromatic carboxylic acid doped silica gels for the first time. For Tb0.8 Ln0.2 (Sal)3 x H2O (Ln3+:Gd3+ or Nd3+)-doped silica gel, the addition of Gd3+ increased the luminescence efficiency of Tb3+, while the luminescence of Tb3+ was quenched remarkably with the addition of Nd3+. Possible mechanism behind the co-luminescence phenomena of lanthanide complexes-doped silica gels is discussed.

Field evaluation of an immunochromatographic test for diagnosis of cystic and alveolar echinococcosis.

BACKGROUND: The larval stages of the tapeworms Echinocoocus granulosus and Echinococcus multilocularis are the causative agents of human cystic echinococcosis (CE) and human alveolar echinococcosis (AE), respectively. Both CE and AE are chronic diseases characterised by long asymptomatic periods of many years. However, early diagnosis of the disease is important if treatment and management of echinococcosis patients are to be successful. METHODS: A previously developed rapid diagnostic test (RDT) for the differential detection of CE and AE was evaluated under field conditions with finger prick blood samples taken from 1502 people living in the Ganzi Tibetan Autonomous Prefecture, China, a region with a high prevalence for both forms of human echinococcosis. The results were compared with simultaneously obtained abdominal ultrasonographic scans of the individuals. RESULTS: Using the ultrasonography as the gold standard, sensitivity and specificity, and the diagnostic accuracy of the RDT were determined to be greater than 94% for both CE and AE. For CE cases, high detection rates (95.6-98.8%) were found with patients having active cysts while lower detection rates (40.0-68.8%) were obtained with patients having transient or inactive cysts. In contrast, detection rates in AE patients were independent of the lesion type. The positive likelihood ratio of the RDT for CE and AE was greater than 20 and thus fairly high, indicating that a patient with a positive test result has a high probability of having echinococcosis. CONCLUSIONS: The results suggest that our previously developed RDT is suitable as a screening tool for the early detection of human echinococcosis in endemic areas.

[Establishment and evaluation of colloid gold labeled immunochromatographic strip test for rapid diagnosis of malaria].

OBJECTIVE: To establish and evaluate a gold immunochromatographic strip test for detection and differentiation of Plasmodium vivax and P. falciparum. METHODS: The monoclonal antibodies, F4H12, G4C9 and D8F7, were conjugated with colloid gold as detecting reagent; monoclonal antibody B2G10 (against P. vivax/ P. falciparum) and D6A7 (only against P. falciparum) were immobilized on nitrocellulose in proper position. Blood samples from 107 febrile patients from endemic area of malaria and 17 patients with visceral leishmaniasis were used for evaluating the specificity. Blood samples of malaria patients (110 with P. vivax and 54 with P. falciparum) were used for evaluating the sensitivity. RESULTS: 5 samples out of 107 febrile patients and 17 patients with visceral leishmaniasis showed false positive reaction with a specificity of 96.0% (119/124), all the 17 samples from patients with visceral leishmaniasis were negative. 164 blood samples of malaria patients showed a sensitivity of 92.3% (153/164), 92.7% (102/110)and 94.4% (51/ 54) for patients infected with P. vivax or P. falciparum, respectively. CONCLUSION: The immunochromatographic strip test based on antigen-capturing is a sensitive, specific, simple and rapid assay for malaria diagnosis.

[Asymptomatic Leishmania infection in human population of Wenxian County, Gansu Province].

OBJECTIVE: To analyze the status of Leishmania infantum asymptomatic infection in human population of a Kala-azar endemic area in Wenxian County, Gansu Province, and to evaluate the tests used. METHODS: Blood samples were tested by PCR using two pairs of primers, RV1-RV2 and K13A-K13B, for detecting Leishmania-specific DNA. ELISA and rK39-dipstick were used to detect Leishmania-specific antibodies. RESULTS: The positive rate of PCR, ELISA and rK39-dipstick was 30.9%(83/269). 24.2%(65/269) and 0 (0/269) respectively. CONCLUSION: The prevalence of asymptomatic infection of L. infantum in humans is high in the area. PCR test based on RV1-RV2 and K13A-K13B primer pairs is a sensitive and specific method for detecting the asymptomatic infection.

[Study on PCR method for detecting the asymptomatic infection of Leishmania infantum].

OBJECTIVE: To establish PCR method for the detection of the asymptomatic infection of Leishmania infantum. METHODS: Six primer pairs were selected for detecting Chinese strain of L. infantum by optimizing conditions which affect amplification. Their sensitivity and specificity were compared by using DNAs extracted from human blood seeded with cultured L. infantum promastigotes (MHOM/CN/86/GS) as template. Blood samples of the inhabitants without symptoms of visceral leishmaniasis in the endemic area were analyzed with two selected primer pairs with good sensitivity and specificity. RESULTS: The specificity of all six primer pairs reached 100%, and the sensitivity varied among the primer pairs. The primer pairs RV1-RV2 (0.1 parasite/ml blood) and K13A-K13B (1 parasite/ml blood) were most sensitive. Leishmania DNA was detected in 33% (33/100) and 30% (30/100) human blood samples by RV1-RV2 and K13A-K13B primer pairs respectively. CONCLUSION: This study suggests that RV1-RV2 and K13A-K13B primer pairs are suitable in detecting the asymptomatic infection of L. infantum, and the prevalence of the asymptomatic infection is high in human population in the endemic area.