Testing Of Reagents Research Articles

Quality of HIV laboratory testing in Tanzania: a situation analysis

Tanzania is scaling up prevention, treatment, care and support of individuals affected with HIV. There is therefore a need for high quality and reliable HIV infection testing and AIDS staging. The objective of this study was to assess laboratories capacities of services in terms of HIV testing and quality control. A baseline survey was conducted from December 2004 to February 2005 in 12 laboratories which were conveniently selected to represent all the zones of Tanzania. The questionnaires comprised of questions on laboratory particulars, internal and external quality control for HIV testing and quality control of reagents. Source and level of customer satisfaction of HIV test kits supply was established. Of 12 laboratories, nine used rapid tests for screening and two used rapid tests for diagnosis. In the 12 laboratories, four used double ELISA and five used single ELISA and three did not use ELISA. Confirmatory tests observed were Western Blot in three laboratories, DNA PCR in two laboratories, CD4 counting in seven laboratories, and viral load in two laboratories. Although all laboratories conducted quality control (QC) of the HIV kits, only two laboratories had Standard Operating Procedures (SOPs). Internal and external quality control (EQC) was done at varied proportions with the highest frequency of 55.6% (5/9) for internal quality control (IQC) for rapid tests and EQC for ELISA, and the lowest frequency of 14.3% (1/ 7) for IQC for CD4 counting. None of the nine laboratories which conducted QC for reagents used for rapid tests and none of the five which performed IQC and EQC had SOPs. HIV kits were mainly procured by the Medical Store Department and most of laboratories were not satisfied with the delay in procurement procedures. Most of the laboratories used rapid tests only, while some used both rapid tests and ELISA method for HIV testing. In conclusion, the survey revealed inadequacy in Good Laboratory Practice and poor laboratory quality control process for HIV testing reagents, internal and external quality control.

Pathogenesis and treatment of systemic lupus erythematosus nephritis

Glomerulonephritis is a challenging complication of systemic lupus erythematosus that still results in kidney loss in up to 30% of patients. In this review we highlight the development of integrated efforts to link pathogenesis with disease definition and new therapeutics. Immune complex deposition in the kidney initiates an inflammatory cascade that causes glomerular disease but there are many modulating factors including genetic predisposition, products of the innate immune system, cytokines, complement and activated cells (both renal and immune). Animal models can help dissect potential disease mechanisms but the study of multiple models will be required since there are multiple subsets of human disease. Recent therapeutic studies in humans address the distinction between therapies for remission induction and remission maintenance. Multiple studies confirm the therapeutic equivalence of mycophenolate mofetil and cyclophosphamide in induction of remission but results are still far from ideal. The next few years should see the testing of new biologic reagents in humans. Another area of interest is the search for noninvasive measures of disease and disease response. Although there has been remarkable progress in our understanding of the immunology and phenotype of lupus nephritis current therapies have insufficient efficacy. As new therapies emerge, improved clinical design coupled with mechanistic studies will be needed to identify agents that may be effective only in some patient subpopulations.

Characterization of newly established oral cancer cell lines derived from six squamous cell carcinoma and two mucoepidermoid carcinoma cells

Since genetic abnormalities of human cancer are greatly geographically dependent, cultural and environmental backgrounds are thought to be closely related to the carcinogenic process. In the present study, eight human cell lines were established by culture from untreated carcinomas of the oral cancer, of which five were from primary oral squamous cell carcinomas (OSC), one from a mucoepidermoid carcinoma (MEC) and one each originating from metastatic OSC and MEC. All the studied tumor lines grew as monolayers, and showed: i) an epithelial origin by the presence of cytokeratin, and ii) tumorigenic potential in nude mice. Western blot analysis revealed i) over expression of EGFR in six of the cell lines ii) decreased expression of E-cadherin in six cell lines compared to normal human oral mucosa. A mutational analysis showed: point mutations of p53 at exon 7, with transversion, and at exon 8, with transition. These well-characterized human YD cell lines should serve as useful tools in the study of the molecular pathogenesis and biological characteristics of head and neck cancer cells, and in the future testing of new therapeutic reagents for oral cancer.

Molecular analyses of mycobacteria other than the M. tuberculosis complex isolated from Northern Ireland cattle

Mycobacteria other than the Mycobacterium tuberculosis complex (MOTT), isolated from Northern Ireland cattle, were identified by PCR amplification of the 16S rRNA gene, and subsequent reverse cross blot hybridisation and sequence analyses. Elucidation of the MOTT species was to facilitate specificity testing of new and existing diagnostic test reagents for bovine tuberculosis. The presence of the genes for potential diagnostic antigens: MPB70, MPB64, ESAT-6 and CFP-10 in the isolated MOTT species was investigated. Molecular analyses of cultured isolates from bovine lymph node specimens of 48 cattle identified a wide variety of mycobacterial species including Mycobacterium nonchromogenicum, Mycobacterium malmoense, Mycobacterium bohemicum, Mycobacterium paratuberculosis, Mycobacterium avium, Mycobacterium kansasii, Mycobacterium holsaticum, Mycobacterium palustre, Mycobacterium sp. IWGMT 90210, Mycobacterium sp. LIV-2129, a potentially novel mycobacterial species (EMBL/GenBank/DDBJ Accession Number AJ617495) and Rhodococcus equi. Apart from M. kansasii, the results of traditional (standard phenotypic and biochemical) and molecular identification methods did not correlate well, with traditional methods identifying fewer species. Most of the species identified were either recognised pathogenic or potential pathogenic species. The genes for ESAT-6, CFP-10 and, unusually, MPB64 were detected in M. kansasii only. The MPB70 gene was not detected in any of the species. This study supported restricted species distribution of these genes as well as identifying a different range of MOTT species that could be included in specificity testing of new diagnostic reagents for bovine tuberculosis.

Development and standardization of multiplexed antibody microarrays for use in quantitative proteomics

BackgroundQuantitative proteomics is an emerging field that encompasses multiplexed measurement of many known proteins in groups of experimental samples in order to identify differences between groups. Antibody arrays are a novel technology that is increasingly being used for quantitative proteomics studies due to highly multiplexed content, scalability, matrix flexibility and economy of sample consumption. Key applications of antibody arrays in quantitative proteomics studies are identification of novel diagnostic assays, biomarker discovery in trials of new drugs, and validation of qualitative proteomics discoveries. These applications require performance benchmarking, standardization and specification.ResultsSix dual-antibody, sandwich immunoassay arrays that measure 170 serum or plasma proteins were developed and experimental procedures refined in more than thirty quantitative proteomics studies. This report provides detailed information and specification for manufacture, qualification, assay automation, performance, assay validation and data processing for antibody arrays in large scale quantitative proteomics studies.ConclusionThe present report describes development of first generation standards for antibody arrays in quantitative proteomics. Specifically, it describes the requirements of a comprehensive validation program to identify and minimize antibody cross reaction under highly multiplexed conditions; provides the rationale for the application of standardized statistical approaches to manage the data output of highly replicated assays; defines design requirements for controls to normalize sample replicate measurements; emphasizes the importance of stringent quality control testing of reagents and antibody microarrays; recommends the use of real-time monitors to evaluate sensitivity, dynamic range and platform precision; and presents survey procedures to reveal the significance of biomarker findings.

Proposal for translational analysis and development of clinical radiolabeled immunoglobulin therapy

Background and purpose: Radiolabeled immunoglobulin therapy (RIT) can be a selective, effective, low-toxicity outpatient cancer therapy. A consensus on the best approach for the preclinical and clinical development of RIT reagents needs to be developed. We report the M.D. Anderson Cancer Center prior experience in translating RIT from laboratory to clinic for the treatment of Hodgkin's disease and propose a flow diagram for the development of RIT for other malignancies. Material and methods: Three different animal models are described: nude mice bearing human tumor xenografts, normal beagle dogs, and normal rhesus monkeys. We produced and purified antibodies and prepared chelate-immunoconjugates reactive with six different human tumor-associated antigens. The Igs used were derived from rabbits, mice, and humans (human-derived RIT reagents being less immunogenic in human patients). Eighty patients with refractory Hodgkin's disease were treated with radiolabeled antiferritin. Results: We recommend a two-injection scheme using, (1) an indium-111-labeled radioimmunoconjugate for diagnosis, pharmacokinetic studies, and dosimetry, and (2) a yttrium-90-labeled radioimmunoconjugate for therapy. The animal models provide useful data on tumor targeting, radiotoxicology, and undesirable biodistributions. A 70% response rate is obtained in patients with advanced recurrent Hodgkin's disease. More extensive preclinical testing allows for safer and more effective clinical RIT studies. Conclusions: We recommend, (1) preclinical optimization of chelation chemistry, Ig size, Ig origin, route of administration, and fractionation, (2) new clinical Phase I–III studies more appropriate for RIT development than the classical Phase I–III studies used for the development of chemotherapeutic agents, and (3) more extensive preclinical testing of RIT reagents.

State-of-the-Art Review : Monitoring of High-Dose Intravenous Heparin Therapy—A Contribution to the Safety of Heparin Monitoring

Whenever unfractionated heparin (UFH) is administered i.v. in therapeutic doses, therapeutic drug monitoring of the anticoagulant response should be man datory and the dose should be adjusted accordingly. UFH therapy is usually monitored by the activated partial thromboplastin time (APTT). A 1.5- to 2.5-fold prolonga tion of APTT has become generally accepted as an indi cator of effective i.v. anticoagulation, but it has become common to recommend this ratio without testing the APTT reagents used for their heparin sensitivity and for their actual therapeutic APTT ratio (actual APTT: normal control APTT). Internal heparin sensitivity testing of APTT reagents is managed using heparin sensitivity curves obtained from heparin-spiked normal plasma pool. The most common APTT reagents in Austria and a newly developed double activated APTT reagent were tested for their heparin sensitivity and therapeutic ratios on differ ent automated analyzers, depending on their optical and chemical conditions. Also, newly developed, commer cially prepared heparin standards (0.19, 0.52, 0.86 IU heparin/ml plasma) were tested. APTT reagents differ in their heparin sensitivity and therapeutic ratio; variations in heparin sensitivity are also seen between different an alyzers. Therefore, therapeutic ratio should regularly be checked and the literature should always state which APTT reagent was used on which instrument.

Modeling Human Lymphoid Precursor Cell Gene Therapy in the SCID-hu Mouse

Gene therapy of human T-lymphocyte disorders, including acquired immunodeficiency syndrome (AIDS), would be greatly facilitated by the development of an in vivo system in which transduced human hematopoietic stem cells can be used to reconstitute the T-lymphoid compartment. Here we use the SCID-hu mouse as a recipient for human CD34+ hematopoietic progenitor cells transduced in vitro with a retroviral vector carrying the neomycin resistance gene (neoR). The transduced cells engraft and reconstitute the lymphoid compartments of the human thymus implant with as few as 5 x 10(4) CD34+ cells. The neoR gene was expressed at low levels in human thymocytes and there was no apparent effect on thymocyte differentiation as a result of vector transduction. Thus, this SCID-hu mouse system is the first in vivo model showing human thymopoiesis after transduction of exogenous vectors, and should allow preclinical testing of gene therapeutic reagents designed to function in human cells of the T-lymphoid lineage. Because human immunodeficiency virus type 1 infection induces depletion of human thymocytes in SCID-hu mice, this system may be particularly valuable in evaluating efficacy of gene therapies to combat AIDS.

Modeling human lymphoid precursor cell gene therapy in the SCID-hu mouse

Gene therapy of human T-lymphocyte disorders, including acquired immunodeficiency syndrome (AIDS), would be greatly facilitated by the development of an in vivo system in which transduced human hematopoietic stem cells can be used to reconstitute the T-lymphoid compartment. Here we use the SCID-hu mouse as a recipient for human CD34+ hematopoietic progenitor cells transduced in vitro with a retroviral vector carrying the neomycin resistance gene (neoR). The transduced cells engraft and reconstitute the lymphoid compartments of the human thymus implant with as few as 5 x 10(4) CD34+ cells. The neoR gene was expressed at low levels in human thymocytes and there was no apparent effect on thymocyte differentiation as a result of vector transduction. Thus, this SCID-hu mouse system is the first in vivo model showing human thymopoiesis after transduction of exogenous vectors, and should allow preclinical testing of gene therapeutic reagents designed to function in human cells of the T-lymphoid lineage. Because human immunodeficiency virus type 1 infection induces depletion of human thymocytes in SCID-hu mice, this system may be particularly valuable in evaluating efficacy of gene therapies to combat AIDS.

Use of novel therapeutic agents for the treatment of serious infection

The use of biologic reagents directed against invading microbes and deleterious aspects of the host response is presently under intense investigation. The development and use of these reagents have contributed significantly to our understanding of the host response to infection, and they probably represent the first true foray into the area of immunotherapeutic manipulation. Thus, the effects of the administration of anti-endotoxin and antitumor necrosis factor-alpha monoclonal antibodies and the interleukin-1 receptor antagonist are being examined in large-scale clinical trials, and tumor necrosis factor-binding protein and bactericidal/permeability-increasing protein also may undergo clinical testing. Much controversy has already arisen regarding the manner in which these therapeutic reagents will be best utilized. The enormous amount of information that has already been obtained concerning the use of these reagents assuredly will contribute significantly to our understanding of the diagnosis and treatment of serious infection and will set the stage for the development and appropriate testing of additional new diagnostic and therapeutic reagents during the current decade.

Scientific and Technological Challenges in Mineral Processing

Due to increasingly complex mineralogy, steadily decreasing ore grades and ever increasing economic and environmental pressures, the mineral processing industry over the past decade had to evolve appropriate means to treat these difficult-to-process ore deposits. Some of the important emerging trends and the evolutionary changes which have occurred in mineral processing technology; are reviewed. This includes the areas of quantifying mineral liberation, in the design of new size reduction devices like high pressure rolls mills, advances in gravity separation and magnetic separation, development of new flotation machines like column flotation and flash flotation, design and testing of new flotation reagents and the new technologies based on a combination of physical and chemical separation methods are reviewed. The challenging areas of current research efforts have been highlighted.

Basic phenotyping of lymphocytes: Selection and testing of reagents and interpretation of data

Basic phenotyping of lymphocytes: Selection and testing of reagents and interpretation of data

Testing and evaluation of reagents for mineral flotation

The selection, testing, and commercial utilization of flotation reagents is best carried out in stages through microflotation tests on pure minerals and their synthetic mixtures followed by bench-scale batch flotation tests on the ore. A systematic approach to quantitatively evaluate different reagents, in particular, through the analysis of batch flotation data, has been presented in this paper. It is recommended that the reagents are compared both in terms of their performance with respect to the recovery-time as well as the recovery-grade plots. While the former describes the kinetic aspects of reagent interaction, the latter is a measure of its selectivity for a particular separation problem.

Accelerated-degradation testing of immunodiagnostic reagents.

Accelerated-degradation testing of immunodiagnostic reagents.

Ames Salmonella/mammalian-microsome testing of peptides and peptide synthesis reagents

The Ames Salmonella/mammalian-microsome assay was used to evaluate the bacterial mutagenicity of 6 bioactive peptides and of 11 chemical reagents used in peptide synthesis. Samples of 2 reagents, bis(2-oxo-3-oxazolidinyl)phosphinic chloride and fluoren-9-ylmethyl chloroformate, showed mutagenic activity with strains TA100 and TA1535, and with TA1537, respectively. No mutagenic activity was found with the bioactive peptides or with the other 9 peptide synthesis reagents.

Nonmicrobial alternative to reagent quality control testing.

The traditional approach to quality control in microbiology involves the routine testing of both media and reagents with live microbial cultures. This is expensive, time consuming, and subject to the variables associated with the use of live organisms. A system of reagent quality control based on the pure chemical form of the metabolic end products important to the identification of the Enterobacteriaceae was evaluated. The metabolite reagent control system is simple, reliable, and extremely cost effective, and it eliminates the need for live microbial cultures and media for reagent quality control.

Removal of Heavy Metal and Halide Contamination from Macronutrient Salts

In micronutrient deficiency experiments with plants the salts used to supply macronutrients must obviously be free of significant contamination. Hewitt (4), in reviewing the testing and purification of nutrient reagents, clearly pointed out that there is no guarantee that even the purest salts commercially available are sufficiently free of the known micronutrients, and that routine use of an appropriate purification procedure is amply justified by many examples of improvement gained in deficiency technique. Routine purification is further justified if it can be done more easily than analytical testing of reagents in search of the occasional highly pure batch. While recrystallization has been extensively used as a general purification procedure, Hughes (5) and Iewitt (4) have pointed out that more effective processes for specific groups of micronutrients are needed. This view is supported by data on the effectiveness of recrystallization which we have included in this report. We have applied a number of procedures with the aim of removing specific micronutrients. For example, micronutrient metals have been removed by adsorption on calcium phosphate (1), by coprecipitating with CuS and FeS (2, 4, 11) and by extracting with 8-quinolinol (4, 9), while chloride has been removed by adding AgNO3 as well as by recrystallizing (2). Some of these processes have not been highly effective, and all are somewhat time-consuming. Accordingly we have developed two new proceduresevaporative treatment with HNO3 to remove halides, and coprecipitation with Mg(OH)2 to remove heavy metal cations. Both are exceedingly simple as well as effective.

The testing of organic reagents for inorganic analysis

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe testing of organic reagents for inorganic analysisHelmut M. Haendler Cite this: J. Chem. Educ. 1939, 16, 2, 66Publication Date (Print):February 1, 1939Publication History Received3 August 2009Published online1 February 1939Published inissue 1 February 1939https://doi.org/10.1021/ed016p66RIGHTS & PERMISSIONSArticle Views51Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

The Stability of Schick Toxin

The stability of the biological reagents used in routine immunological procedures is a matter of practical interest to the public health worker, and an attempt has been made in the following research to estimate the period during which the diluted toxin used in the Schick test for the estimation of susceptibility to diphtheria remains potent. In the early days of Schick testing, although Leete (1920) reported that a diluted toxin retained its potency for as long as 5 weeks, it has hitherto been considered inadvisable to use a toxin at a longer interval than 48 hours after it had been diluted to its proper strength. Glenny, Waddington and Pope (1928) and O'Brien, Okell and Parish (1928) have introduced a new diluent consisting of a solution of a combination of crystal borax 57, boric acid 84 and sodium chloride 99 parts. A 1·5 per cent, solution of this mixture is now used as a diluent and has the effect of sustaining the potency of the diluted toxin over a greater period of time. In our work over 400 persons have been tested with toxins made up according to this formula, a comparison being made in each individual between the reactions elicited by an aged toxin, stored for varying periods at room temperature or in the cold room, with those produced by a fresh toxin. Enough toxin was made up at the beginning of the experiment to last over a considerable period of time, samples being sent to us by post periodically together with batches of freshly diluted toxin. The testing of reagents was carried out immediately on receipt, the lower age groups being selected in any series of individuals as being likely to give the largest number of reactors. The actual testing was performed practically throughout by one of us (J. C. J. McEntee) so as to maintain uniformity of technique. Each pair of toxins was controlled by a single injection of inactivated toxin and the results were scrutinised at the 4th and 10th days, a record of the comparative intensities of the positives being made at the same time. The results are recorded in Table I.

The Testing of Chemical Reagents for Purity

CAVEAT EMPTOR is a good maxim, if a somewhat hackneyed quotation. The principle it embodies need not be disregarded, even by the chemist. True, he is a protector of the purchasing public in certain cases where that public cannot take care of itself; but this does not absolve him from the necessity of keeping a watchful eye upon his own purchases. On the contrary, the very fact that he may be called upon, for instance, to certify to the purity of other people's food makes it all the more incumbent upon him to look well after the purity of his own reagents. It may happen—and it has happened—that through insufficient attention to the quality of his chemicals, an analyst may introduce into some article the very impurity which he is required to search for, or an investigator in pure chemistry may be led to propound some brilliant theory which more circumspect working presently renders untenable. As examples in point, one need only recall the testing of foodstuffs for arsenic, and the alleged conversion of this element into antimony. Wherefore, when the chemist buys his chemicals let him remember the legal tag above quoted, and not trust too implicitly to the manufacturer who supplies them. The Testing of Chemical Reagents for Purity. By Dr. C. Krauch. Third Edition. Authorised translation by J. A. Williamson, F.C.S., and L. W. Dupré. Pp. 350. (London: Maclaren and Sons, n.d.) Price 12s. 6d. net.