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Herrera D.,Science and Technology Information Institute IDICT | Gonzalez E.C.,Immunoassay Center | Lavaut K.,Docent Paediatric Hospital William Soler
Journal of Neonatal-Perinatal Medicine | Year: 2013

BACKGROUND: Gaucher disease (GD) is a lysosomal storage disorder characterized by a deficiency of the lysosomal acid β-D-glucosidase (GBA). The aim of this study was to develop an ultramicro-fluorometric assay based on the method of Chamoles et al. for determining GBA activity in dried blood spots on filter paper (DBS). METHODS: The assay used 3-mm diameter blood spot and 8 mmol/l of 4-methylumbelliferyl-β-D-glucoside as enzymatic substrate. The reaction occurred in plates incubated at 37°C for 20 hours and the enzyme activity was expressed in μmol hydrolysed substrate/l blood/h. The fluorescence of the enzyme product was automatically measured in a fluorometer-photometer reader (SUMA Technology). RESULTS: The intra and inter-assay coefficients of variation were lower than 9 and 12%, respectively, and the recovery range was 97-109%.Three patients with GD were correctly diagnosed using the ultramicroassay. Healthy newborn DBS samples (n = 3003) from the National Neonatal Screening Program were analyzed, and the mean GBA activity was 5.7 μmol/l blood/h. Our assay showed high Pearson (n = 26; r = 0.99) and concordance correlations (ρc = 0.99) with the traditional method described by Chamoles et al. CONCLUSIONS: The analytical performance characteristics of our ultramicro-fluorometric assay suggest that it can be used in the diagnosis of GD in newborns and adults. © 2013 - IOS Press and the authors. All rights reserved.


Castells Martinez E.M.,Immunoassay Center | del Valle R.,Immunoassay Center | Gonzalez E.C.,Immunoassay Center | Melchor A.,Immunoassay Center | Perez P.L.,Immunoassay Center
Journal of Immunoassay and Immunochemistry | Year: 2016

Human epidermal growth factor is a small peptide consisting of 53 amino acid residues, which stimulates cell proliferation and is associated with several human carcinomas. A simple sandwich-type ultramicroELISA assay (UMELISA), based on the advantages of high affinity reaction between streptavidin and biotin has been developed for the measurement of EGF in human serum samples. Strips coated with a high affinity monoclonal antibody directed against EGF are used as solid phase, to ensure the specificity of the assay. The EGF assay was completed in 18 hr, with a measuring range of 39–2500 pg/mL. The intra- and inter-assay coefficients of variation were 4.4–7.3% and 0–5.1%, respectively, depending on the EGF concentrations evaluated. Percentage recovery ranged from 96–104%. Regression analysis showed a good correlation with the commercially available Human EGF Immunoassay Quantikine® ELISA kit (n = 130, r = 0.92, P < 0.01). The analytical performance characteristics of our UMELISA EGF endorse its use for the quantification of EGF in human serum samples. © 2016 Taylor & Francis


Gonzalez Fernandez R.S.,University of Habana | Gonzalez Fernandez R.S.,Immunoassay Center
MEDICC Review | Year: 2014

A review was conducted of screening strategies for detecting the main cancer sites for which screening has been recommended, assessing WHO and other international organizations' positions, as well as the requirements of Cuba's cancer control strategy. Universally, screening is recommended for cervical, breast and colorectal cancer, all included in the Cuban strategy. Additionally, in Cuba, PSA testing is indicated for men considered at risk (aged >45 years with family history) and those aged >50 years who request it; annual oral exams and teaching of oral self-examination are recommended for the entire population; and for adults aged >35 years, active annual oral cancer case finding. Screening for skin cancer is performed by physical examination of individuals at risk. To maximize benefits of early cancer detection, greater coverage is needed as well as studies of how well screening is performing under current Cuban conditions.


Perez L.,Immunoassay Center | Zulueta O.,Immunoassay Center | Melchor A.,Immunoassay Center | Hernandez L.,Immunoassay Center | And 3 more authors.
Hybridoma | Year: 2011

Human prostate-specific antigen (hPSA) is found in serum and semen in a variety of forms, is form-free and complex, and has clinical importance to prostate cancer diagnosis. Here, a simple procedure is described for the efficient purification of hPSA from seminal plasma. The semen was clarified by centrifugation, and the isolation of PSA was carried out by immunoaffinity chromatography using the monoclonal antibody anti total PSA CB-PSA.4. The recuperation of PSA from seminal plasma by this procedure was 66.4%, and a purification factor of 65.8 was reached. The specificity activity obtained was 0.79 mg PSA/mg protein, and the preparation appeared homogeneous by SDS-PAGE and immunoelectrophoresis. A molecular weight of preparation was 30.46 kDa by SDS-PAGE, similar to the commercial PSA. These results indicate that immunoaffinity purification of PSA by means of this monoclonal antibody is a simple one-step procedure for the production of biologically active, highly purified human PSA. © Copyright 2011, Mary Ann Liebert, Inc.


Gonzalez-Fernandez R.S.,Immunoassay Center | Gonzalez-Fernandez A.,Julio Diaz National Rehabilitation Hospital
MEDICC Review | Year: 2016

Intersectoral action in health refers to actions led by the health sector based on coordinated national and local policies, strategically oriented to address priority health issues where actions by other sectors can have a decisive impact on health outcomes. A Cuban example of this approach is the joint efforts by the Ministry of Public Health and the biotechnology industry in development and application of technologies for cervical cancer screening, early detection and treatment. The resulting products have been used by the National Health System since 2010, as part of efforts to reduce cervical cancer mortality. This is an example of intersectoral action intended to identify and contribute to solving problems affecting people's well-being and quality of life.


Frometa A.,Immunoassay Center | Reyes E.C.G.,Immunoassay Center | Castells E.,Immunoassay Center | Tejeda Y.,Immunoassay Center | And 2 more authors.
Journal of Perinatal Medicine | Year: 2011

Background: To describe a simple, rapid, quantitative ultramicrotest (UMTEST) based on the fluorometric method introduced by Fujimura et al. adapted to an Ultra Micro Analytic System (SUMA) for the detection of total galactose (GAL) in dried blood specimens. Methods: The assay uses 3 mm discs of dried blood on Whatman 903 filter paper and small volumes of each reagent. A methanol/acetone/water solution is used for deproteination, and a specially designed 96-well polystyrene opaque ultramicroplates, with a maximum capacity of 30 μL per well, are used for the reading. Results: The UMTEST GAL is completed in 2 h, with measuring range of 0.28-3.92 mmol/L. The intra-and inter-assay coefficients of variation were 2.3%-8.9% and 6.8%-11.1%, respectively, depending on the total GAL concentrations. Percentage recovery ranged from 97.7% to 103%. Limit of detection and limit of quantitation were 0.06 and 0.16 mmol/L, respectively. The mean GAL concentration, in 2510 dried blood samples from the National Neonatal Screening Program was 0.23 mmol/L. Our assay showed high concordance correlations with the commercially available ICN Immuno-Chem™ GAL-MW EA kit. Conclusions: The analytical performance characteristics of this assay is suitable for mass newborn screening of galactosemia in Cuba. © 2011 by Walter de Gruyter Berlin New York.


Arce Quintana J.L.,Immunoassay Center | Lobaina R.,Immunoassay Center | Hernandez Collado Y.,Immunoassay Center | Garcia Sardinas R.,Immunoassay Center | And 2 more authors.
Journal of Laboratory Automation | Year: 2013

This article is about how to improve the positional dispensing accuracy of low-volume (microliters) drops and to understand the factors affecting them. These same parameters can be investigated to reduce deleterious effects on dispensing performance. Many applications, such as those in immunoassay diagnostics, require accurate volumetric dispensing and are also less tolerant of other phenomena that cause the reagent to be located outside the target area of interest. In this article, we work with liquid inertia. This phenomenon is present in positional dispensing and affects its accuracy. The negative effect of liquid inertia is reduced by changing parameters such as pressure and the diameter of the involved conducts. © 2013 Society for Laboratory Automation and Screening.


PubMed | Immunoassay Center
Type: Journal Article | Journal: Journal of laboratory automation | Year: 2013

This article is about how to improve the positional dispensing accuracy of low-volume (microliters) drops and to understand the factors affecting them. These same parameters can be investigated to reduce deleterious effects on dispensing performance. Many applications, such as those in immunoassay diagnostics, require accurate volumetric dispensing and are also less tolerant of other phenomena that cause the reagent to be located outside the target area of interest. In this article, we work with liquid inertia. This phenomenon is present in positional dispensing and affects its accuracy. The negative effect of liquid inertia is reduced by changing parameters such as pressure and the diameter of the involved conducts.


Human prostate-specific antigen (hPSA) is found in serum and semen in a variety of forms, is form-free and complex, and has clinical importance to prostate cancer diagnosis. Here, a simple procedure is described for the efficient purification of hPSA from seminal plasma. The semen was clarified by centrifugation, and the isolation of PSA was carried out by immunoaffinity chromatography using the monoclonal antibody anti total PSA CB-PSA.4. The recuperation of PSA from seminal plasma by this procedure was 66.4%, and a purification factor of 65.8 was reached. The specificity activity obtained was 0.79 mg PSA/mg protein, and the preparation appeared homogeneous by SDS-PAGE and immunoelectrophoresis. A molecular weight of preparation was 30.46 kDa by SDS-PAGE, similar to the commercial PSA. These results indicate that immunoaffinity purification of PSA by means of this monoclonal antibody is a simple one-step procedure for the production of biologically active, highly purified human PSA.


PubMed | Immunoassay Center
Type: Evaluation Studies | Journal: Journal of perinatal medicine | Year: 2011

To describe a simple, rapid, quantitative ultramicrotest (UMTEST) based on the fluorometric method introduced by Fujimura et al. adapted to an Ultra Micro Analytic System (SUMA) for the detection of total galactose (GAL) in dried blood specimens.The assay uses 3 mm discs of dried blood on Whatman 903 filter paper and small volumes of each reagent. A methanol/acetone/water solution is used for deproteination, and a specially designed 96-well polystyrene opaque ultramicroplates, with a maximum capacity of 30 L per well, are used for the reading.The UMTEST GAL is completed in 2 h, with measuring range of 0.28-3.92 mmol/L. The intra- and inter-assay coefficients of variation were 2.3%-8.9% and 6.8%-11.1%, respectively, depending on the total GAL concentrations. Percentage recovery ranged from 97.7% to 103%. Limit of detection and limit of quantitation were 0.06 and 0.16 mmol/L, respectively. The mean GAL concentration, in 2510 dried blood samples from the National Neonatal Screening Program was 0.23 mmol/L. Our assay showed high concordance correlations with the commercially available ICN Immuno-Chem GAL-MW EA kit.The analytical performance characteristics of this assay is suitable for mass newborn screening of galactosemia in Cuba.

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