Prevalence and risk factors for proximal deep vein thrombosis at admission in patients with traumatic fractures: a multicenter retrospective study.

Objective: This study aimed to determine the associated risk factors for proximal deep vein thrombosis (DVT) in patients with lower extremity and pelvic-acetabular fractures. Methods: The medical records of 4,056 patients with lower extremity and pelvic-acetabular fractures were retrospectively reviewed. The patients were classified into proximal or non-proximal DVT groups. Logistic regression models were used to determine the independent risk variables for proximal DVT. The predictive value of the related risk factors was further analyzed using receiver operating characteristic curves. Results: The prevalence of proximal DVT was 3.16%. Sex, body mass index (BMI), fracture site, injury mechanism, diabetes, coronary heart disease (CHD), injury-to-admission interval, hematocrit, platelet counts, and D-dimer levels differed significantly between the two groups. BMI ≥ 24.0 kg/m2, femoral shaft fractures, high-energy injury, diabetes, injury-to-admission interval >24 h were independent risk factors for proximal DVT. CHD decreased the risk of proximal DVT. The platelet and D-dimer had high negative predictive value for predicting proximal DVT formation, with cut-off values of 174 × 109/L and 2.18 mg/L, respectively. Conclusion: BMI ≥ 24.0 kg/m2, femoral shaft fractures, high-energy injury, diabetes, injury-to-admission interval >24 h were independent risk factors for proximal DVT in patients with lower extremity and pelvic-acetabular fractures. Platelet count and D-dimer level were effective indicators for excluding proximal DVT occurrence. CHD decreased the risk of proximal DVT.

Risk factors for hypoxaemia following hip fracture surgery in elderly patients who recovered from COVID-19: a multicentre retrospective study.

Objectives: To explore the risk factors associated with postoperative hypoxaemia in elderly patients who have recovered from coronavirus disease (COVID-19) and underwent hip fracture surgery in the short term. Design: Multicentre retrospective study. Setting: The study was performed in three first 3A-grade hospitals in China. Participants: A sequential sampling method was applied to select study participants. Medical records of 392 patients aged ≥65 years who had recovered from COVID-19 and underwent hip fracture surgery at three hospitals in China between 1 November, 2022, and 15 February, 2023, were reviewed. Interventions: Patients were assigned to hypoxaemia or non-hypoxaemia groups, according to whether hypoxaemia occurred after surgery. Univariate and multivariate logistic regression analyses were used to identify independent risk factors for postoperative hypoxaemia. Results: The incidence of postoperative hypoxaemia was 38.01%. Statistically significant differences were found between the two groups in terms of age, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, presence of expectoration symptoms, preoperative hypoxaemia, chronic obstructive pulmonary disease, pulmonary inflammation, time between recovery from COVID-19 and surgery, anaesthetic mode, surgical procedure, intraoperative blood loss, intraoperative infusion, duration of surgery, and length of hospital stay (p < 0.05). Furthermore, patients with BMI ≥28.0 kg/m2, expectoration symptoms, presence of preoperative hypoxaemia, ASA classification III, time between recovery from COVID-19 and surgery ≤2 weeks, and general anaesthesia were potential risk factors for postoperative hypoxaemia. Conclusion: Obesity, expectoration symptoms, preoperative hypoxaemia, ASA classification III, time between recovery from COVID-19 and surgery ≤2 weeks, and general anaesthesia were potential risk factors for postoperative hypoxaemia in elderly patients who recovered from COVID-19 and underwent hip fracture surgery in the short term.

Incidence and Risk Factors of Admission Deep Vein Thrombosis in Patients With Traumatic Fracture: A Multicenter Retrospective Study.

To identify risk factors of admission deep vein thrombosis (DVT) in patients with traumatic fractures. Medical records of 1596 patients with traumatic fractures were reviewed. According to the ultrasound reports of the lower extremity veins, patients were assigned to the DVT or non-DVT group. Univariate and multivariate logistic regression analyses were used to identify the independent risk factors of DVT, and the receiver operating characteristic (ROC) curve was used to analyze the predictive value of the D-dimer level for DVT. DVT admission incidence was 20.67%. Statistically significant differences were revealed between the 2 groups in terms of age, sex, fracture site, presence of hypertension, coronary heart disease, stroke, smoking status, time from injury to admission, and levels of fasting blood glucose, hemoglobin, fibrinogen, D-dimer, and hematocrit. Multivariate analysis results showed that age above 50 years, female, above-knee fracture, cigarette smoking, injury-to-admission delay beyond 48 h, low hemoglobin levels, high fasting blood glucose levels, and high D-dimer levels were independent risk factors for admission DVT. ROC analysis showed that the D-dimer level was effective for the prediction of admission DVT in patients with peri-knee and below-knee fractures (area under the curve [AUC] = 0.7296, cutoff point = 1.21 mg/L). An age over 50 years, female, above-knee fracture, smoking, injury-to-admission delay beyond 48 h, decreased hemoglobin level, and increased fasting blood glucose and D-dimer levels were found to be potential independent risk factors for admission DVT. In patients with peri-knee and below-knee fractures, the plasma D-dimer level was effective in predicting admission DVT.

A Wider and Deeper Peptide-Binding Groove for the Class I Molecules from B15 Compared with B19 Chickens Correlates with Relative Resistance to Marek's Disease.

The chicken MHC is known to confer decisive resistance or susceptibility to various economically important pathogens, including the iconic oncogenic herpesvirus that causes Marek's disease (MD). Only one classical class I gene, BF2, is expressed at a high level in chickens, so it was relatively easy to discern a hierarchy from well-expressed thermostable fastidious specialist alleles to promiscuous generalist alleles that are less stable and expressed less on the cell surface. The class I molecule BF2*1901 is better expressed and more thermostable than the closely related BF2*1501, but the peptide motif was not simpler as expected. In this study, we confirm for newly developed chicken lines that the chicken MHC haplotype B15 confers resistance to MD compared with B19. Using gas phase sequencing and immunopeptidomics, we find that BF2*1901 binds a greater variety of amino acids in some anchor positions than does BF2*1501. However, by x-ray crystallography, we find that the peptide-binding groove of BF2*1901 is narrower and shallower. Although the self-peptides that bound to BF2*1901 may appear more various than those of BF2*1501, the structures show that the wider and deeper peptide-binding groove of BF2*1501 allows stronger binding and thus more peptides overall, correlating with the expected hierarchies for expression level, thermostability, and MD resistance. Our study provides a reasonable explanation for greater promiscuity for BF2*1501 compared with BF2*1901, corresponding to the difference in resistance to MD.

Assessing Ecosystem Services Supply-Demand (Mis)Matches for Differential City Management in the Yangtze River Delta Urban Agglomeration.

With the global increase in population and urban expansion, the simultaneous rise of social demand and degradation of ecosystems is omnipresent, especially in the urban agglomerations of China. In order to manage environmental problems and match ecosystem supply and social demand, these urban agglomerations promoted regional socio-ecological integration but ignored differential city management during the process of integration. Therefore, it is necessary to design a general framework linking ecosystem supply and social demand to differential city management. In addition, in previous studies, ecosystem services supply-demand amount (mis)match assessment was emphasized, but ecosystem services supply-demand type (mis)match assessment was ignored, which may lead to biased decisions. To deal with these problems, this study presented a general ecosystem services framework with six core steps for differential city management and developed a double-indices (amount and type) method to identify ecosystem services supply-demand (mis)matches in an urban agglomeration. This framework and the double-indices method were applied in the case study of the Yangtze River Delta Urban Agglomeration. Ecosystem supply-demand amount and type (mis)match levels and spatial pattern of twenty-six cities were identified. Twenty-six cities in the YRDUA were classified into five kinds of cities with different levels of ES supply-demand (mis)matches for RS, three kinds of cities for PS, and four kinds of cities for CS. Differential city management strategies were designed. Despite its limitations, this study can be a reference to giving insights into ES supply-demand (mis)match assessment and management.

The Prognostic Value of Intraoperative Neuromonitoring by Combining Somatosensory- and Motor-Evoked Potentials for Thoracic Spinal Decompression Surgery in Patients with Neurological Deficit.

STUDY DESIGN: Retrospective study. OBJECTIVE: To explore a relation between somatosensory- and motor-evoked potential (SEPs, MEPs) and corresponding thoracic cord function for thoracic spinal decompression surgery (TSDS) in patients with neurological deficit. SUMMARY OF BACKGROUND DATA: Although SEPs and MEPs monitoring has been developed as an essential technique in spinal surgery. There are limited data on the reliability of using SEPs and MEPs for TSDS and its prognosis. METHODS: One hundred twenty patients underwent TSDS in our hospital, 91 patients completed the trial. All the patients were divided into three subgroups according to the changes of MEPs and SEPs: neither SEPs nor MEP deteriorated -. Simply MEP deteriorated and both SEPs and MEP deteriorated -. Bispectral (BIS) was used to monitor the depth of sedation, which ranged from 40 to 60 by varying the infusion speed of anesthetics. The pre- and postoperative spinal function was assessed by muscle strength and Japanese Orthopaedic Association (JOA) score at three time points:1) before surgery; 2) immediately after general anesthesia recovery; 3) after 3-month follow-up. RESULTS: Sixty-nine cases showed neither SEPs nor MEP deteriorated -, 10 cases showed only MEP deteriorated, and 12 cases showed both SEPs and MEP deteriorated -. The patients in the group where neither SEPs nor MEP deteriorated had the best recovery of the extremity muscle strength, the shortest recovery time (8.10 ±â€Š1.60, P < 0.05), and toe movement time (8.50 ±â€Š1.60, P < 0.05). There is a strong correlation between SEPs variability ratio at T4 time point and JOA recovery ratio (JOA RR) in the 3-month follow-up. CONCLUSION: Combined SEPs and MEPs monitoring are important for TSDS in patients with neurological deficit and it is helpful for evaluating postoperative prognosis. It is more accurate to record SEPs at T4 time point to predict the patients' prognosis.Level of Evidence: 3.

Spatiotemporal Change and the Natural-Human Driving Processes of a Megacity's Coastal Blue Carbon Storage.

Coastal blue carbon storage (CBCS) plays a key role in addressing global climate change and realizing regional carbon neutrality. Although blue carbon has been studied for some years, there is little understanding of the influence of a megacity's complex natural and human-driven processes on CBCS. Taking the Shanghai coastal area as an example, this study investigated the spatiotemporal change in CBCS using the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) model during 1990-2015, and analyzed the response of the CBCS to a megacity's complex natural- and human-driven processes through a land use/land cover transition matrix and hierarchical clustering. The results were as follows: (1) Thirty-three driving processes were identified in the study area, including four natural processes (e.g., accretion, succession, erosion, etc.), two human processes (reclamation and restoration) and twenty-seven natural-human coupled processes; they were further combined into single and multiple processes with positive and negative influences on the CBCS into four types (Mono+, Mono-, Multiple+ and Multiple- driving processes). (2) Shanghai's CBCS increased from 1659.44 × 104 Mg to 1789.78 ×104 Mg, though the amount of Shanghai's coastal carbon sequestration showed a decreasing trend in three periods: 51.28 × 104 Mg in 1990-2000, 42.90 × 104 Mg in 2000-2009 and 36.15 × 104 Mg in 2009-2015, respectively. (3) There were three kinds of spatiotemporal patterns in the CBCS of this study area: high adjacent to the territorial land, low adjacent to the offshore waters in 1990; high in the central part, low in the peripheral areas in 2009 and 2015; and a mixed pattern in 2000. These patterns resulted from the different driving processes present in the different years. This study could serve as a blueprint for restoring and maintaining the CBCS of a megacity, to help mitigate the conflicts between socioeconomic development and the conservation of the CBCS, especially in the Shanghai coastal area.

Thermal and Humidity Effect of Urban Green Spaces with Different Shapes: A Case Study of Shanghai, China.

Research shows that urban green spaces (UGSs) provide a number of positive effects, including enhancing human thermal comfort levels by decreasing air temperature (AT) and increasing relative humidity (RH). However, research on how the shape of an UGS influences these effects is yet to be explored. This paper explores the principles and features behind this. The AT and RH surrounding an UGS within a horizontal scale of 20 m was explored. Microclimate field measurements around 35 UGSs in Shanghai, China were carried out. The samples covered the most applied types of UGSs-punctiform, linear, and planar. Comparison spots were selected away from the sampled UGSs. The effects were studied by data collection and statistical analysis. The results indicate that the shape of the UGS had significant impact on the Temperature Humidity Index (THI). In the summer, the amplitude of THI variation decreases with the distance to UGS. For punctiform UGS, a larger total area and existence of water body results in a lower THI. A wider, linear UGS with the same orientation as the direction of the prevailing wind contributes more to decrease the surrounding THI. The total area of planar UGS is not critical. A higher landscape shape index of a planar UGS is the critical point to achieve a lower THI. The results can serve as a reference when planning and designing future UGSs.

Accuracy of ultrasound to measure the cricoid cartilage diameter in children.

BACKGROUND: Ultrasonography is used to pre-operatively predict the endotracheal tube size required for intubation by measuring the cricoid cartilage diameter. This study aimed to determine the accuracy of ultrasound measurements of the transverse diameters of the cricoid cartilage in children. METHODS: We examined 50 children who underwent magnetic resonance imaging (MRI) scans at the HongHui Hospital, Xi'an Jiaotong University, from February 2019 to December 2019. Each child underwent MRI and ultrasound scans for measurement of the transverse diameters of the cricoid cartilage. The data measured by each technique were compared using Bland-Altman analysis and linear regression analysis. RESULTS: Results of linear regression and Bland-Altman analysis showed strong correlation in the level of agreement between MRI and ultrasound measurements (r = 0.94, P < .001). The estimated bias was 0.11 mm; precision, 0.25 mm; and the limit of agreement, -0.47 to 0.70 mm. CONCLUSION: Ultrasound is a reliable tool for measuring the transverse diameters of the cricoid cartilage in children.

The effect of habitat changes along the urbanization gradient for breeding birds: an example from the Xiong'an New Area.

BACKGROUND: Because of its status as an ecocivilization pilot city, fundamental research on spatial distribution patterns and impact factors of the avian community within the Xiong'an New Area is necessary for future ecological planning and mitigation of negative impacts from future urbanization. Gradient research within small cities can provide important information for the development of urbanization gradient patterns of avian communities. METHODS: A total of 30 sample points within the urbanization gradient were selected, and avian communities and environmental variables were measured within a 50 m radius sample circle. Principal component regression analysis was used to analyze bird-environment relationships. The Sorensen dissimilarity index was used to calculate the beta-diversity. RESULTS: Our results showed that there was a significant urban-rural pattern with a gradient phenomenon in avian communities. Results of this study showed more resident, passenger and insectivore species, and a higher density of breeding insectivore and omnivore individuals appear in the urban fringe than in the other areas. A relatively high value of overall beta-diversity and spatial isolation probably exists among the three disjunct constructed regions. Both species richness and individual abundance were significantly influenced by the species diversity of the trees and foliage height diversity (FHD). DISCUSSION: Based on our results and our goal of avian species diversity conservation, we first suggest that urban green spaces be established and ensure a high complexity of vegetation structure as this is critically needed to increase avian species α-diversity within habitat patches. Second, different habitat types within and around the three constructed areas should be developed based on the important existing bird habitats to increase avian diversity in each city, especially in the areas within Xiongxian and Rongcheng that are well protected, and to elevate the beta-diversity of the total region. Finally, based on the biodiversity hotspots identified by this research, ecological corridors should be carefully planned to improve the stability of regional bird communities.

LncRNA Snhg3 contributes to dysfunction of cerebral microvascular cells in intracerebral hemorrhage rats by activating the TWEAK/Fn14/STAT3 pathway.

LncRNA small nucleolar RNA host gene 3 (Snhg3) has been involved in cell proliferation and migration in malignant cells. However, its role in regulating functions of non-malignant cells has been hardly reported. Here, we found Snhg3 expression was sharply induced in primary brain microvascular endothelial cells (BMVECs) treated with oxygen-and-glucose-deprivation (OGD) plus hemin, an in vitro model of intracerebral hemorrhage (ICH). Downregulation of Snhg3 by siRNA transfection improved cell proliferation and migration abilities and reduced cell apoptosis and monolayer permeability in BMVECs under treatment with OGD plus hemin. Snhg3 overexpression suppressed cell proliferation and migration and increased cell apoptosis and monolayer permeability under normal condition. In ICH rats, downregulation of Snhg3 by siRNA injection improved behavioral and histological manifestations, including number of right turns, limb placement score, integrity of blood-brain barrier (BBB), brain water content and cell apoptosis in vivo. In the mechanism exploration, we found that, TWEAK and Snhg3 displayed a positive correlation with each other. Snhg3 overexpression increased expression of TWEAK protein and its receptor Fn14, that were also induced by OGD plus hemin, activating the downstream neuroinflammatory pathway STAT3 and enhancing the secretion of MMP-2/9. Finally, the TWEAK-siRNA, the Fn14 inhibitor ATA and the STAT3 blocker AG490 were respectively used to treat BMVECs under treatment with OGD plus hemin. Our results showed either TWEAK downregulation, Fn14 inhibition, or STAT3 blockade, could rescue Snhg3-induced impairment of BMVEC functions. In conclusion, the lncRNA Snhg3 contributes to dysfunction of cerebral microvascular cells in ICH rats by activating the TWEAK/Fn14/STAT3 pathway.

Electrosorptive removal of salt ions from water by membrane capacitive deionization (MCDI): characterization, adsorption equilibrium, and kinetics.

Capacitive deionization (CDI) was demonstrated to be an affordable technology for reduction of salt concentrations in brackish water. In this study, a novel membrane capacitive deionization (MCDI) cell was assembled by incorporating ion exchange membranes into the CDI cell which was built with high-adsorption electrodes based on ordered mesoporous carbon. The synthesized mesoporous carbon electrode was fully characterized. The simultaneous analysis of the electrosorption capacity and adsorption/desorption kinetics was evaluated by using real power plant desulfurization wastewater. The ordered mesoporous carbon was favorable for salt ion electrosorption, and the best performance was obtained by using MCDI which improved the removal efficiency of total dissolved solids (TDSs) from 65 to 82%. The total hardness and alkalinity of the effluent after treatment could meet the requirement of water quality standard for industries. Langmuir isotherm and pseudo-first-order kinetic models were found to be in best agreement with experimental results of salt ion electrosorption. The selective transport of ions between the electrode surface and bulk solution due to the ion exchange membranes resulted in a better desalination performance of MCDI. The results presented in this paper could be used for developing new electrode materials of MCDI for desalination from water.

Genome-Wide Identification of the Aux/IAA Family Genes (MdIAA) and Functional Analysis of MdIAA18 for Apple Tree Ideotype.

The Aux/IAA (auxin/indole-3-acetic acid) gene family is one of the early auxin-responsive gene families, which play a central role in auxin response. Few reports are involved in Aux/IAA genes in fruit trees, especially in apple (Malus × domestica Borkh.). A total of 33 MdIAA members were identified, of which 27 members contained four conserved domains, whereas the others lost one or two conserved domains. Several cis-elements in promoters of MdIAAs were predicted responsive to hormones and abiotic stress. Tissue-specific expression patterns of MdIAAs in different apple tree ideotypes were investigated by quantitative real-time PCR. A large number of MdIAAs were highly expressed in leaf buds and reproductive organs, and MdIAAs clustered in same group showed similar expression profiles. Overexpression of MdIAA18 in Arabidopsis resulted in compact phenotype. These results indicated that MdIAA genes may be involved in vegetative and reproductive growth of apple. Taken together, the results provide useful clues to reveal the function of MdIAAs in apple and control apple tree architecture by manipulation of MdIAAs.

[Continuous lumbar plexus block reduces the incidence of early postoperative cognitive dysfunction in elderly patients undergoing hip arthroplasty].

OBJECTIVE: To observe the impacts of continuous lumbar plexus block (CLPB) on postoperative cognitive dysfunction (POCD) in elderly patients undergoing hip arthroplasty.
 Methods: Sixty elderly patients scheduled for hip arthroplasty with general anesthesia, were randomly allocated into a CLPB group and a PCIA group (n=30 each). In the CLPB group, lumbar plexus block was performed before trachea intubation, and CLPB was used for postoperative analgesia. In the PCIA group, intravenous analgesia was controlled in patients after operation. Visual Analogue Scale (VAS) at 12, 24, and 48 h after operation was recorded. Mini-Mental State Examination (MMSE) scale was used to evaluate the cognitive dysfunction at the 1st day before operation (D0) and at the 1st (D1), 3rd (D3), and 7th (D7) days after operation and the occurrence of POCD was recorded. S-100ß concentrations were detected by ELISA at D1, D3, and D7. Postoperative adverse events were recorded.
 Results: VAS scores at 12, 24, and 48 h after operation in the CLPB group were significantly lower than those in the PCIA group (P<0.05). Compared with the PCIA group, the MMSE scores were significantly higher (P<0.05), and the incidence of POCD at D1 and D3 was obviously reduced in the CLPB group (P<0.05). S-100ß concentration at D1 and D3 in the CLPB group was significantly lower than that in the PCIA group (P<0.05).
 Conclusion: Application of CLPB in elderly patients undergoing hip arthroplasty could obviously relieve their postoperative pain, inhibit the production of S-100ß, and reduce the incidence of early postoperative cognitive dysfunction.

Identifying hotspots and management of critical ecosystem services in rapidly urbanizing Yangtze River Delta Region, China.

Rapid urbanization has altered many ecosystems, causing a decline in many ecosystem services, generating serious ecological crisis. To cope with these challenges, we presented a comprehensive framework comprising five core steps for identifying and managing hotspots of critical ecosystem services in a rapid urbanizing region. This framework was applied in the case study of the Yangtze River Delta (YRD) Region. The study showed that there was large spatial heterogeneity in the hotspots of ecosystem services in the region, hotspots of supporting services and regulating services aggregately distributing in the southwest mountainous areas while hotspots of provisioning services mainly in the northeast plain, and hotspots of cultural services widespread in the waterbodies and southwest mountainous areas. The regionalization of the critical ecosystem services was made through the hotspot analysis. This study provided valuable information for environmental planning and management in a rapid urbanizing region and helped improve China's ecological redlines policy at regional scale.

Comparison of plasma microRNA-1 and cardiac troponin T in early diagnosis of patients with acute myocardial infarction.

BACKGROUND: Early reperfusion can effectively treat acute myocardial infarction (AMI) and reduce the mortality significantly. This study aimed to compare the role of plasma microRNA-1 (miR-1) and cardiac troponin T (cTnT) in early diagnosis of AMI patients. METHODS: From May 2011 to May 2012, plasma samples were collected from 56 AMI patients and 28 non-AMI controls. The expression of plasma miR-1 was measured by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and the level of plasma cTnT was measured using electrochemiluminescence-based methods on an Elecsys 2010 Immunoassay Analyzer. SPSS 16.0 was used for the statistical analysis of the results. Data were expressed as mean±standard deviation unless otherwise described. The differences about clinical characteristics between the AMI patients and controls were tested using Student's t test or Fisher's exact test. The Mann-Whitney U test was conducted to compare the expression of microRNAs between the AMI patients and controls. MicroRNAs expression between different intervals of the AMI patients was compared using Wilcoxon's signed-rank test. The receiver operating characteristic (ROC) curve was established to discriminate the AMI patients from the controls. RESULTS: In the present study, the expression of plasma miR-1 was significantly increased in the AMI patients compared with the healthy controls (P<0.01). The plasma miR-1 in the AMI patients decreased to the normal level at 14 days (P>0.05). The expression of plasma miR-1 was not related to the clinical characteristics of the study population (P>0.05). ROC curve analyses demonstrated that miR-1 was specific and sensitive for the early diagnosis of AMI, but not superior to cTnT. CONCLUSION: Plasma miR-1 could be used in the early diagnosis of AMI, but it is similar to cTnT.

[Purification of Taq DNA polymerase expressed in Escherichia coli].

Taq DNA polymerase is one of the most commonly thermostable DNA polymerases in molecular biological researches, which shares its basic characters with others of the family, thereby its purifying strategy could be used not only in itself production but also in the extraction of the others as a reference. At present, the protocols reported for large scale preparation of Taq DNA are high cost, so a cheaper method was described here. In this protocol, by heat denaturation, ammonium sulfate precipitation and cation exchange chromatography of 724 resin, about 18 g powder of Na form resin could recover about 27.07 mg of Taq enzyme. The total activity and specific activity were approximately 2.2 × 105 U and 8131.98 U/mg. The total yield was about 48.92% with 59.35 of purification folds. Analysis of quality of purified enzyme indicated that only one protein 94 kDa was identified against SDS-PAGE and the remnant of DNA nuclease was not detected. For PCR reaction, The amplification ability of purified Taq polymerase was not different from that of the commercially avail-able ones. This method reported in the present study is effective and low cost, making it suitable for general purification in laboratories or business production.

A duplex real-time reverse transcription polymerase chain reaction for the detection and quantitation of avian leukosis virus subgroups A and B.

Avian leukosis is a disease that is spreading widely in the world causing large economic losses to the poultry industry. In this study, a duplex quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) assay was developed to detect and quantify avian leukosis virus subgroups A and B (ALVA/B). The assay was optimised to measure viral gp85 and chicken housekeeping (ß-actin) genes. The result showed that the assay was specific for reference strains of ALVA/B subtype and no cross-reaction was detected with ALV subtypes E and J or with four other non-ALV viruses. The assay detected as few as 56 gp85 cDNA copies and was 100-fold more sensitive than a conventional RT-PCR. Seventy clinical blood samples were evaluated by both the qRT-PCR and the conventional RT-PCR assay, and the results show that 65 samples were positive by the qRT-PCR compared with 43 by the conventional RT-PCR. When this assay was used to quantify the viral load in ALV-inoculated embryos from three congenic chicken lines, the embryos from the B21 line showed the highest viral load, whereas the lowest load was found in the B5 line. This assay provides a powerful tool for quantitative detection of the ALVA/B and for the study of host genetic resistance to avian leukosis.