用NucliSens HIV-1 QT试剂盒定量测定精浆中的HIV-1 RNA

目的探讨NucliSens HIV-1 QT试剂盒用于定量测定HIV-1感染者人群精液或精浆中HIV-1的可行性。方法在正常人精液、精浆和血浆中分别添加5个滴度的HIV-1RNA,用NucliSens HIV-1QT测定,观察精液和精浆成分对测定结果有无影响,进一步测定、分析15名HIV-1感染者血浆和精浆中的HIV-1病毒载量。结果发现精液中因含有严重抑制核酸扩增的现象故不能使用NucliSens HIV-1QT,但精浆中未见该抑制现象。用Nu-cliSens HIV-1QT测定分别添加HIV-1RNA的正常人血浆和精浆样本,结果之间差异无统计学意义;所测定的10份正常人精浆样本,未发现假阳性结果。在15名HIV-1感染者中,血浆和精浆的HIV-1检出率分别为80%(12/15)和40%(6/15),病毒载量范围分别为(<250-140000)cp/ml和(<250-46000)cp/ml。结论NucliSens HIV-1QT可用于定量测定HIV-1感染者人群精浆中的HIV-1,精浆和血浆中HIV-1病毒载量之间具有一定的相关性。     

Influence of time and storage conditions on plasma HIV viral load measurements

Quantification of human immunodeficiency virus (HIV) RNA in plasma from HIV-infected patients is now widely used as a clinical indicator of disease prognosis and of response to antiretroviral therapy. However, controversy exists as to whether values obtained under different testing conditions could vary significantly, thus jeopardizing the appropriate interpretation of data. Herein, we demonstrate that results obtained after testing plasma versus whole blood, or immediate versus deferred processing, do not appear to influence viral load measurements significantly. Thirty blood samples from HIV-infected patients were analysed. The second generation branched-DNA assay was used for quantification of plasma viral load. HIV RNA remained stable for at least 24 h at room temperature, either in plasma or in whole blood, in 72.4% of the samples (< 0.2 log difference in viral load values) although lower levels of HIV RNA tend to be seen in samples after being stored as whole blood at room temperature. Only 3.4% of samples showed a decline > 0.5 log when they were left as whole blood at room temperature for 24 h in comparison with testing after immediate plasma separation. Although immediate separation and refrigeration of plasma samples may reduce the chance of significant falls in viral load measurements, this level of processing can be limited in regions where clinical blood samples cannot be processed rapidly. Our data provide confidence in the results obtained when testing specimens, either plasma or whole blood, 24 h after venepuncture and storage at room temperature, mimicking the conditions in the transport of blood samples to reference centres.     

Glycosylated hemoglobin measured by affinity chromatography: micro-sample collection and room-temperature storage

Under proper conditions, whole blood can be stored at room temperature for as long as 21 days before measurement of glycosylated hemoglobin by affinity chromatography. Whole blood (anticoagulated with EDTA or heparin) was placed in capillary tubes, which were then sealed at both ends and stored at room temperature. Just before assay, whole blood was rinsed from the tubes and diluted 10-fold with water. Samples of each patient's blood were assayed as whole-blood hemolysates by affinity chromatography after zero, seven, 14, and 21 days of storage. Values for glycosylated hemoglobin did not change over 21 days of storage and values for each storage day correlated well (r = 0.97, p less than .0001) with hemoglobin A1C measured in fresh erythrocyte hemolysates by "high-performance" liquid ion-exchange chromatography.     

Effect of transport conditions on the stability of biochemical markers in blood

We examined the stability of lipids, carotenoids, alpha-tocopherol, and endogenous hormones in plasma prepared from whole blood that had been mailed to a central location for processing. Initially, to simulate transport conditions, whole-blood samples were stored in the laboratory, either at room temperature or cooled, for up to 72 h before processing. In the latter samples, lipid concentrations changed up to 1.4% per day, carotenoids up to -5.5%, and hormones up to 9.5%. In a second study, analyte concentrations in plasma from cooled whole blood mailed via overnight courier were compared with those from plasma that had been immediately separated, frozen, and mailed via overnight courier. Concentrations of cholesterol, high-density lipoprotein subfraction 3, apolipoprotein B, and retinol were stable. Overall, for each marker except estradiol, the between-person variation was at least twice the within-person variation. In a third study, at least 340 micrograms of DNA was recovered from 30 mL of cool-shipped whole blood. Our results indicate that shipping whole-blood samples by overnight courier is feasible for assay of several biochemical markers of interest in epidemiological research.     

Evaluation of hepatitis C virus RNA stability in room temperature and multiple freeze–thaw cycles by COBAS AmpliPrep/COBAS TaqMan HCV

To assess the stability of various sample types and storage conditions for quantitative detectability of hepatitis C virus (HCV) RNA viral loads, we studied serum and EDTA/citrate plasma samples obtained from 10 patients known to be positive for HCV RNA. Samples were subjected to the following conditions: 1) 10 freeze–thaw (FT) cycles, and 2) storage at room temperature for 24, 48, and 72 h. Detection of HCV RNA was performed by COBAS AmpliPrep/COBAS TaqMan HCV. The following conclusions were reached: 1) no significantly different viral loads were observed in different blood compartments; 2) no significantly different viral loads were observed after 24, 48, and 72 h at room temperature; 3) no significantly different viral loads were observed after 10 FT cycles in serum and plasma samples; and 4) HCV RNA is quite stable in serum and plasma (EDTA/citrate) samples.     

West Nile virus in blood: stability,distribution, and susceptibility to PEN110 inactivation

BACKGROUND: The outbreak of West Nile virus (WNV) is the most recent reminder that the blood supply continues to be vulnerable to emerging and reemerging pathogens. A potentially prospective approach to reducing the risk of transfusion-transmitted infections of a known or newly emerging microbe is implementation of a broad-spectrum pathogen reduction technology. The purpose of this study was to evaluate the susceptibility of WNV to PEN110 inactivation in RBCs and to characterize the WNV interaction with blood, including the stability of WNV in RBCs stored at 1 to 6 degrees C, its distribution and infectivity, and its ability to infect WBCs. STUDY DESIGN AND METHODS: Inactivation was performed with three WNV isolates spiked into WBC-reduced RBCs. The stability of the virus was evaluated by spiking two viral loads into RBCs followed by storing at 1 to 6 degrees C for up to 42 days. The distribution of the virus in plasma, RBCs, and PBMCs was evaluated with whole blood from infected hamsters. Finally, in vitro propagation of WNV was evaluated with the THP-1 cell line and primary monocytes. RESULTS: The kinetics of PEN110 inactivation of WNV isolates RI-44, NJ-176, and 99-3494031 were fast and complete within 24 hours with reduction factors of 5 to 7 log plaque-forming units per mL. WNV remained infectious for up to 42 days at 1 to 6 degrees C. The WNV titers in whole blood, plasma, RBCs, and PBMC fractions were equally distributed and ranged from 2 to 3 log tissue culture infectious dose 50 percent per mL. Productive infection of stimulated monocytes and THP-1 cells was also demonstrated. CONCLUSIONS: These studies demonstrated that PEN110 efficiently inactivated WNV in RBCs and whole blood from infected hamsters to the limit of detection. WNV survived in RBCs stored at 1 to 6 degrees C with a gradual loss of titer but infectivity could still be observed for up to 42 days. In addition, it was observed that WNV was equally distributed in all blood fractions including PBMCs and it was possible to establish productive infection of a human monocytic cell line and stimulated human monocytes.     

Effect of anticoagulants and storage temperatures on stability of plasma and serum hormones

OBJECTIVES: To determine the effect of different anticoagulants and storage conditions on the stability of hormones in plasma and serum. DESIGN AND METHODS: Human blood samples were collected from volunteers into EDTA, lithium heparin, sodium fluoride/potassium oxalate, or tubes without anticoagulant, plasma and serum left at -20 degrees C, 4 degrees C or 30 degrees C for 24 and 120 hours then assayed for ACTH, aldosterone, alpha-subunit, AVP, CRH, C-peptide, estradiol, FSH, glucagon, GH, IGF-1, IGFBP-3, insulin, leptin, LH, PPP, PTH, prolactin and VIP, or at room temperature for 0 to 72 hours (BNP, NT-BNP)(n = 6 per condition). RESULTS: The anticoagulant altered the measured concentrations for 9 hormones when compared to EDTA. All hormones except ACTH were stable for > 120 hours in EDTA or fluoride at 4 degrees C, but only 13 hormones were stable in all anticoagulants. At 30 degrees C, 8 hormones were stable for > 120 hours in EDTA, and 3 hormones in all anticoagulants. BNP and NT-BNP were stable for < 24 hours when stored in EDTA or heparin at room temperature. DISCUSSION: Storage of samples in EDTA plasma at 4 degrees C is suitable for most hormones (except ACTH) for up to 120 hours.     

Human immunodeficiency virus type 1 protease inhibitors irreversibly block infectivity of purified virions from chronically infected cells.

Synthetic peptide analog inhibitors of human immunodeficiency virus type 1 (HIV-1) protease were used to study the effects of inhibition of polyprotein processing on the assembly, structure, and infectivity of virions released from a T-cell line chronically infected with HIV-1. Inhibition of proteolytic processing of both Pr55gag and Pr160gag-pol was observed in purified virions from infected T cells after treatment. Protease inhibition was evident by the accumulation of precursors and processing intermediates of Pr55gag and by corresponding decreases in mature protein products. Electron microscopy revealed that the majority of the virion particles released from inhibitor-treated cells after a 24-h treatment had an immature or aberrant capsid morphology. This morphological change correlated with the inhibition of polyprotein processing and a loss of infectivity. The infectivity of virion particles purified from these chronically infected cell cultures was assessed following treatment with the inhibitor for 1 to 3 days. Virions purified from cultures treated with inhibitor for 1 or 2 days demonstrated a 95- to 100-fold reduction in virus titers, and treatment for 3 days resulted in complete loss of detectable infectivity. The fact that virions from treated cultures were unable to establish infection over the 7- to 10-day incubation period in the titration experiments strongly suggests that particles produced by inhibitor-treated cells were unable to reactivate to an infectious form when they were purified away from exogenous protease inhibitor. Thus, a block of HIV-1 protease processing of viral polyproteins by specific inhibitors results in a potent antiviral effect characterized by the production of noninfectious virions with altered protein structures and immature morphologies.     

Deactivation of human immunodeficiency virus type 1 in medium by copper oxide-containing filters

Human immunodeficiency virus type 1 (HIV-1) can be transmitted through breast-feeding and through contaminated blood donations. Copper has potent biocidal properties and has been found to inactivate HIV-1 infectivity. The objective of this study was to determine the capacity of copper-based filters to inactivate HIV-1 in culture media. Medium spiked with high titers of HIV-1 was exposed to copper oxide powder or copper oxide-impregnated fibers or passed through copper-based filters, and the infectious viral titers before and after treatment were determined. Cell-free and cell-associated HIV-1 infectivity was inhibited when exposed to copper oxide in a dose-dependent manner, without cytotoxicity at the active antiviral copper concentrations. Similar dose-dependent inhibition occurred when HIV-1 was exposed to copper-impregnated fibers. Filtration of HIV-1 through filters containing the copper powder or copper-impregnated fibers resulted in viral deactivation of all 12 wild-type or drug-resistant laboratory or clinical, macrophage-tropic and T-cell-tropic, clade A, B, or C, HIV-1 isolates tested. Viral inactivation was not strain specific. Thus, a novel means to inactivate HIV-1 in medium has been developed. This inexpensive methodology may significantly reduce HIV-1 transmission from "mother to child" and/or through blood donations if proven to be effective in breast milk or plasma and safe for use. The successful application of this technology may impact HIV-1 transmission, especially in developing countries where HIV-1 is rampant.     

Mutations to the probe of Cobas TaqMan HIV-1 ver. 1.0 assay causing undetectable viral load in a patient with acute HIV-1 infection

We encountered a human immunodeficiency virus (HIV)-1 in which the viral load was undetectable with the Cobas TaqMan HIV-1 ver. 1.0 (CTM v.1.0) in a patient with acute HIV-1 infection. The CTM v.1.0 assay showed more than 1,000-fold underestimation compared with the subsequent Cobas Amplicor Monitor v.1.5 assay. Because five mismatches to the CTM v.1.0 assay probe in the HIV-1 virus in the patient were disclosed by the manufacturer, partial gag regions of the HIV genome were directly sequenced from the patient’s plasma viral RNA. The detected single nucleotide point mutations were located near the 5′-end of the Cobas Amplicor Monitor probe. Clinicians should be very careful in making interpretations when indeterminate Western blot analysis results and a low or even undetectable HIV-1 viral load are encountered with the CTM HIV-1 ver. 1.0 assay in patients with suspected acute HIV infection. Repeating Western blot analysis is essential before considering a low HIV-1 viral load to be a false-positive result.     

Quantification of Rifapentine,a Potent Antituberculosis Drug,from Dried Blood Spot Samples Using Liquid Chromatographic-Tandem Mass Spectrometric Analysis

The quantification of antituberculosis drug concentrations in multinational trials currently requires the collection of modest blood volumes, centrifugation, aliquoting of plasma, freezing, and keeping samples frozen during shipping. We prospectively enrolled healthy individuals into the Tuberculosis Trials Consortium Study 29B, a phase I dose escalation study of rifapentine, a rifamycin under evaluation in tuberculosis treatment trials. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantifying rifapentine in whole blood on dried blood spots (DBS) to facilitate pharmacokinetic/pharmacodynamic analyses in clinical trials. Paired plasma and whole-blood samples were collected by venipuncture, and whole blood was spotted on Whatman protein saver 903 cards. The methods were optimized for plasma and then validated for DBS. The analytical measuring range for quantification of rifapentine and its metabolite was 50 to 80,000 ng/ml in whole-blood DBS. The analyte was stable on the cards for 11 weeks with a desiccant at room temperature and protected from light. The method concordance for paired plasma and whole-blood DBS samples was determined after correcting for participant hematocrit or population-based estimates of bias from Bland-Altman plots. The application of either correction factor resulted in acceptable correlation between plasma and whole-blood DBS (Passing-Bablok regression corrected for hematocrit; y = 0.98x + 356). Concentrations of rifapentine may be determined from whole-blood DBS collected via venipuncture after normalization in order to account for the dilutional effects of red blood cells. Additional studies are focused on the application of this methodology to capillary blood collected by finger stick. The simplicity of processing, storage, shipping, and low blood volume makes whole-blood DBS attractive for rifapentine pharmacokinetic evaluations, especially in international and pediatric trials.     

Incidence of anti HIV antibodies and viral antigen in standard and control sera

Most material used for control and calibration in a clinical laboratory is based on pool sera of human origin, guaranteed to be HBsAg-free. Since little information is available on the potential infectivity of HIV, the causative agent of acquired immunodeficiency syndrome (AIDS), 54 control and calibration sera, in routine use, were investigated for the incidence of antibodies to HIV by means of Elisa. Sixteen test specimens ( = 30%) gave positive or borderline Elisa results and were further analysed by immunoblotting, resulting in 15 samples all recognizing gp 160 and partially the p 24, p 31, p 55, p 64 and gp 120 band. Only one sample with borderline Elisa result was negative by this assay. Furthermore, all sera were examined for the presence of viral antigen by a solid phase Elisa. All samples under investigation gave negative antigen Elisa results. Bearing in mind that the sensitivity of this assay is limited to 10 micrograms/l of viral antigen, no conclusion on infectivity should be drawn. The high incidence of HIV-antibodies in the sera investigated demands that this material should be handled with special care by laboratory personnel.     

Immunochemical and biological properties of a mouse monoclonal antibody reactive to prunus necrotic ringspot ilarvirus

A monoclonal antibody reacting with prunus necrotic ringspot ilarvirus was tested in immunochemical studies, neutralization of infectivity assays, and by immuno-electron microscopy. The antibody was able to detect the 27,000 Mr coat protein of prunus necrotic ringspot ilarvirus in western blots and also detected all polypeptide fragments generated after incubation of whole virus with proteolytic enzymes. In neutralization of infectivity studies, the antibody blocked virus infectivity, although it did not precipitate the antigen in agar gel Ouchterlony double diffusion tests. Immuno-electron microscopy confirmed that the antibody coats virions but does not cause clumping. The antibody may be a useful tool for investigating coat protein-dependent initiation of ilarvirus infection.     

不同处理和保存条件下体外HCV RNA稳定性研究

对献血者或病人进行HCV核酸检测时，如果标本的采集、处理、保存不当，会造成病毒核酸降解，从而影响检测结果的真实性。本研究的目的是对不同抗凝剂、不同温度、不同保存时间下的HCV RNA病毒稳定性进行研究，以考察常规采供血过程中，标本采集及保存方式对NAT检测的影响。采集7例HCV RNA阳性献血者的血样，采用不同的抗凝剂、经不同的温度和不同的时间保存后，采用荧光定量PCR方法测定HCV RNA病毒含量，考察HCV RNA的稳定性。结果表明：①不同抗凝剂抗凝的全血于4℃保存48小时过程中，病毒含量下降至原滴度的42．7％；EDTA抗凝组各时间点的滴度均低于其它3组（分别相当于其它3组的67．6％-25．1％）。②ACD抗凝的全血在4、25和37℃保存48小时．病毒含量分剐下降到原滴度的53．8％、72．5％、29．8％。③ACD抗凝的全血离心分离出血浆，4℃或25℃继续保存7天，病毒含量分别下降至原滴度的70．9％和25．1％。④ACD抗凝的全血分离的血浆，反复冻融4次，病毒含量下降到原滴度的38．9％。结论：①用于核酸检测的标本应该用无菌采血管采样；②在无菌采血管采样的前提下，核酸检测标本用未抗凝血、EDTA、ACD、CPDA抗凝血均可；③采集的全血应避免放置37℃以上，ACD抗凝全血在4℃、25℃保存48小时内、37℃保存14小时内，HCV RNA病毒仍较为稳定；④分离后的血浆应避免放置25℃以上，ACD抗凝全血分离后的血浆在4℃保存7天，25℃保存3天，HCV RNA病毒仍比较稳定；⑤血浆标本应避免多次冻融，但冻融3次的血浆HCV RNA病毒含量仍然较为稳定；⑥无菌采样对维持病毒的稳定性非常重要；单纯的机械性溶血并不会明显导致病毒的降解；只要注意无菌的问题和有合适的核酸提取方法去除血红素，HCV RNA病毒实际上比以前认为的要稳定得多。     

Measurement of prostate-specific antigen by use of a novel blood collection and analytical system

BACKGROUND: Prostate-specific antigen (PSA) is widely used in the detection and monitoring of prostate cancer. We developed a system for the self-collection and transport of capillary whole blood for PSA analysis, with the goal of reducing phlebotomy visits and, thus, increasing the access and utilization of PSA in prostate cancer screening and monitoring. METHODS: The blood collection device [BIOSAFE Blood Transport System (BTS] collects 70 microL of blood through a heparin-coated material into 200 microL of stabilizing solution. The diluted whole blood is used for measurement of PSA by a modified version of the Hybritech Tandem-MP PSA Assay. Results were compared for matched samples of professionally and self-collected BTS blood and for matched BTS samples sera from blood collected by venipuncture. Imprecision for the whole-blood PSA measurement was estimated from analysis of whole-blood controls in duplicate, twice per day, over 20 days. RESULTS: BTS samples (n = 140) collected by a qualified healthcare professional compared with serum samples yielded the regression equation: y =1.02x + 0.04 (S(yx) = 0.35; r = 0.99). Comparison of the results for samples (n = 128) collected by the patient without professional assistance with serum samples yielded: y = 1.08x + 0.02 (S(yx) = 0.31; r = 0.99). The between-run CVs at 0.069, 0.53, 2.9, and 10.7 microg/L were 21%, 6.0%, 3.5%, and 3.8%, respectively. PSA was stable in BTS samples stored for 21 days at 18-24 degrees C and for 7 days at 37 degrees C. CONCLUSION: The BIOSAFE BTS system allows accurate and convenient measurement of circulating PSA by a precise method for diluted whole blood.     

Release of anandamide from blood cells.

BACKGROUND: Endogenous ligands of cannabinoid receptors (endocannabinoids), in particular anandamide (arachidonylethanolamide), have been recognized as being of crucial importance in a variety of physiological functions. Plasma concentrations of anandamide have been measured in a number of investigations; however, discrepant data on "normal" anandamide plasma concentrations were reported. Since this might be caused by pre-analytical variables, we investigated the impact of different sample handling conditions on measured plasma anandamide concentrations. METHODS: Blood samples were taken from healthy volunteers in EDTA- or heparin-containing tubes; whole blood samples were kept at +4 degrees C, room temperature, or 37 degrees C, respectively, for up to 120 min before obtaining plasma by centrifugation. Plasma anandamide concentrations were measured by an isotope-dilution liquid chromatography tandem mass spectrometry (LC-MS/MS) method. RESULTS: A marked time- and temperature-dependent increase in plasma anandamide concentrations ex vivo was observed in both EDTA- and heparin-containing tubes. Mean anandamide concentrations approximately doubled when EDTA samples were kept at 4 degrees C for 60 min before centrifugation [immediately centrifuged, 1.3 microg/L (SD 0.3 microg/L); 2.8 microg/L (SD 0.5 microg/L) after storage for 60 min; n=12). After storage of heparinized whole-blood samples for 120 min at 37 degrees C, a mean plasma anandamide concentration of 11.9 microg/L (SD 1.8 microg/L) was found. In cell-free plasma, no increase in anandamide concentrations was found. CONCLUSION: Anandamide is released from blood cells ex vivo at a very high rate; therefore, strictly standardized pre-analytical protocols have to be applied for plasma anandamide determination.     

Comparability of point-of-care whole-blood electrolyte and substrate testing using a Stat Profile Critical Care Xpress analyzer and standard laboratory methods.

BACKGROUND: Rapid technological progress in point-of-care testing allows the measurement of multiple analytes in whole-blood samples. The present study evaluated biosensor-based methods for the measurement of electrolytes and substrates in whole blood using a Stat Profile Critical Care Xpress (Nova Biomedical, Waltham, MA, USA) multiprofile analyzer and their comparability with standard laboratory methods. Because of the increased utilization of arterial blood samples in hospitalized patients and limited information on differences between arterial and venous blood for most routine laboratory tests, analytical differences caused by different sample types were evaluated. METHODS: Whole-blood arterial samples and venous serum samples were obtained from 70 random patients with a variety of diagnoses admitted to the intensive care unit. The Stat Profile Critical Care Xpress analyzer was used to obtain whole-blood electrolyte and substrate profiles. For comparison studies, plasma or serum samples were analyzed according to standard laboratory methods using an Olympus AU 600 analyzer (Olympus Mishima, Shizuoka, Japan). RESULTS: Imprecision, expressed as the coefficient of variation (CV%), was less than 5.7% for all analytes at both high and low concentrations, except for creatinine, with a CV of 13.8% for low and 9.5% for high concentrations. The inaccuracy of electrolyte and substrate measurements in whole blood using a Stat Profile Critical Care Xpress analyzer met the analytical quality specification required for near patient testing, with observed bias within the range -4.5% to 5.3%. Statistically significant correlation (p<0.05) was obtained between standard laboratory methods performed on arterial plasma or venous serum samples on an Olympus AU 600 analyzer and direct whole-blood measurements on the Stat Profile Critical Care Xpress point-of-care analyzer for all parameters tested, although slope and intercept values showed analytical differences for electrolyte measurement. CONCLUSIONS: The Stat Profile Critical Care Xpress multiprofile point-of-care analyzer provides rapid and accurate direct whole-blood measurement with acceptable performance compared to standard laboratory methods. The results obtained for electrolytes and substrates in whole blood were comparable to those for standard laboratory methods using arterial plasma or venous serum samples.