A new method for anti-negative interference of calcium dobesilate in serum creatinine enzymatic analysis.

BACKGROUND: Serum creatinine is a widely used biomarker for evaluating renal function. Sarcosine oxidase enzymatic (SOE) analysis is currently the most widely used method for the detection of creatinine. This method was negatively interfered with by calcium dobesilate, causing pseudo-reduced results. The aim of this study was to explore a new method to alleviate the negative interference of this drug on creatinine detection. METHOD: We formulated eight drug concentrations and 12 creatinine concentrations from serum. The SOE method, the new method, and the Jaffe method were used for detection in five systems. Creatinine biases were analyzed under the conditions with or without the interference of calcium dobesilate, at consistent or inconsistent creatinine concentrations. Creatinine concentrations were also analyzed at three medical decision levels (MDLs). RESULTS: Calcium dobesilate had negative interference in creatinine SOE analysis. With the increase in calcium dobesilate concentrations, the negative bias increases. The new BG method showed an anti-negative interference effect. In the Roche system, the BG method reduced the negative bias from -71.11% to -16.7%. In the Abbott system, bias was reduced from -45.15% to -2.74%. In the Beckman system, the bias was reduced from -65.36% to -7.58%. In the Siemens system, the bias was reduced from -58.62% to -7.58%. In the Mindray system, the bias was reduced from -36.29% to -6.84%. CONCLUSION: The new method alleviated the negative interference of calcium dobesilate in creatinine SOE detection. The negative bias could be reduced from -60% or -70% to less than -20%.

Pyruvate dehydrogenase deficiency disease detected by the enzyme activity of peripheral leukocytes.

BACKGROUND: Pyruvate dehydrogenase complex (PDHC) deficiency is a common neurodegenerative disease associated with abnormal mitochondrial energy metabolism. The diagnosis of PDHC is difficult because of the lack of a rapid, accurate, and cost-effective clinical diagnostic method. METHODS: A 4-year-old boy was preliminarily diagnosed with putative Leigh syndrome based on the clinical presentation. PDHC activity in peripheral blood leukocytes and a corresponding gene analysis were subsequently undertaken. Sodium pyruvate 1-13 C was used for the analysis of PDHC activity in peripheral leukocytes. The genes encoding PDHC were then scanned for mutations. RESULTS: The results showed that the corresponding PDHC activity was dramatically decreased to 10.5 nmol/h/mg protein as compared with that of healthy controls (124.6 ± 7.1 nmol/h/mg). The ratio of PDHC to citrate synthase was 2.1% (control: 425.3 ± 27.1). The mutation analysis led to the identification of a missense mutation, NM_000284.4:g214C>T, in exon 3 of PDHC. CONCLUSION: The peripheral blood leukocyte PDHC activity assay may provide a practical enzymatic diagnostic method for PDHC-related mitochondrial diseases.

Evaluation of a flow cytometric test for G6PD-deficient erythrocytes.

OBJECTIVE: Glucose-6-phosphate dehydrogenase (G6PD) deficiency, an X-linked recessive disorder, is the commonest erythrocytic enzymopathy worldwide. Reliable diagnosis and severity prediction in G6PD-deficient/heterozygous females remain challenging. A recently developed flow cytometric test for G6PD deficiency has shown promise in precisely identifying deficient females. This paper presents our experiences with this test in a subtropical setting and presents a modification in flow cytometric data acquisition strategy. METHODS: The methaemoglobin reduction + ferryl Hb generation-based flow cytometric G6PD test was compared with the screening methaemoglobin reduction test (MRT) and confirmatory G6PD enzyme activity assay (EAA) in 20 G6PD-deficient males, 22 G6PD-heterozygous/deficient females and 20 controls. Stained cells were also assessed for bright/dim G6PD activity under a fluorescent microscope. RESULTS: Flow cytometry separated and quantified %bright cells in heterozygous/deficient females, objectively classifying them into 6 normal (>85% bright cells), 14 intermediate (10-85%) and two G6PD-deficient (<10% bright cells). Concordance with MRT was 89% (55/62 cases) and with EAA was 77% (48/62 cases). Fluorometrically predicted violet laser excitation (405-nm) with signal acquisition in the 425-475 nm region was a technical advancement noted for the first time in this paper. CONCLUSION: Flow cytometry/fluorescence microscopy represent technically straightforward methods for the detection and quantification of G6PD-deficient erythrocytes. Based on our results, we recommend their application as a first-line investigation to screen females who are prescribed an oxidant drug like primaquine or dapsone.

Evaluation of a new measurement method of indoxyl sulfate in hemodialysis patients.

Indoxyl sulfate (IS) is related to the development of cardiovascular disease and total mortality in dialysis patients. High-performance liquid chromatography (HPLC) is the conventional measurement approach. However, the HPLC method is difficult to perform in real time. Recently, the IS Assay Kit "NIPRO", which enables the measuring of total IS by the enzyme method, was developed. This new reagent allows the easy and quick measurement of many samples using the automatic biochemical analyzer. Moreover, it was reported that it demonstrated satisfactory analytical performance. If this enzyme method is useful for measuring IS in hemodialysis, we can expect that the mechanism in which the IS effects adversely on a body as uremic toxins will be clarified. However, the enzyme method is more easily influenced by other coexisting substances. In this study, we have assessed on how the uremic toxins and anticoagulation effect on this new reagent and evaluate whether it can be put into practice effectively for hemodialysis patients. For the enzyme method, accuracy, simultaneous repeatability, linearity, limit of detection, influence of coexisting materials, and correlation with the HPLC method were examined. Accuracy and simultaneous repeatability were satisfactory, and linearity was good. The limit of detection was acceptable, and there was no influence of coexisting materials. With regard to the correlation, the regression equation was y = 0.947X + 7.987 and the correlation coefficient (r) was 0.972. This new reagent showed sufficient fundamental performance and had a good correlation with the conventional HPLC method for assessing the plasma of dialysis patients.

Enzymatic diagnosis of Pompe disease: lessons from 28 years of experience.

Pompe disease is a lysosomal and neuromuscular disorder caused by deficiency of acid alpha-glucosidase (GAA), and causes classic infantile, childhood onset, or adulthood onset phenotypes. The biochemical diagnosis is based on GAA activity assays in dried blood spots, leukocytes, or fibroblasts. Diagnosis can be complicated by the existence of pseudodeficiencies, i.e., GAA variants that lower GAA activity but do not cause Pompe disease. A large-scale comparison between these assays for patient samples, including exceptions and borderline cases, along with clinical diagnoses has not been reported so far. Here we analyzed GAA activity in a total of 1709 diagnostic cases over the past 28 years using a total of 2591 analyses and we confirmed the clinical diagnosis in 174 patients. We compared the following assays: leukocytes using glycogen or 4MUG as substrate, fibroblasts using 4MUG as substrate, and dried blood spots using 4MUG as substrate. In 794 individuals, two or more assays were performed. We found that phenotypes could only be distinguished using fibroblasts with 4MUG as substrate. Pseudodeficiencies caused by the GAA2 allele could be ruled out using 4MUG rather than glycogen as substrate in leukocytes or fibroblasts. The Asian pseudodeficiency could only be ruled out in fibroblasts using 4MUG as substrate. We conclude that fibroblasts using 4MUG as substrate provides the most reliable assay for biochemical diagnosis and can serve to validate results from leukocytes or dried blood spots.

Valor diagnóstico de anticuerpos antipéptido citrulinado del fibrinógeno en la artritis reumatoide / Diagnostic value of anti-fibrinogen citrullinated peptide in rheumatoid arthritis

OBJETIVO: Determinar el valor diagnóstico de los anticuerpos contra un péptido del fibrinógeno citrulinado, en pacientes cubanos con artritis reumatoide (AR), mediante un inmunoanálisis enzimático. MATERIALES Y MÉTODOS: Se sintetizó un péptido del fibrinógeno citrulinado diseñado por predicción informática y se utilizó en un inmunoanálisis enzimático. Participaron 81 pacientes con AR temprana, 81 pacientes con AR establecida, 58 pacientes con otras enfermedades reumáticas e inflamatorias y 43 individuos sanos. Se determinaron los anticuerpos contra el péptido citrulinado del fibrinógeno, antivimentina citrulinada mutada, antipéptidos citrulinados de segunda generación y factor reumatoide mediante el ensayo de inmunoabsorción ligaado a enzimas (ELISA). RESULTADOS: La determinación de anticuerpos contra el péptido citrulinado del fibrinógeno mediante el inmunoanálisis enzimático diseñado mostró el mejor desempeño diagnóstico en pacientes con enfermedad temprana, con el valor más elevado de sensibilidad (84%), valor predictivo negativo (85%), índice de Youden (0,73%) y área bajo la curva operativa del receptor (0,9192). La especificidad (89%) y el valor predictivo positivo (88%) fueron superiores al factor reumatoide, similar al ensayo antivimentina citrulinada mutada, pero inferiores al ensayo antipéptidos citrulinados de segunda generación. La positividad de proteína C reactiva se asoció a la presencia de anticuerpos contra el péptido citrulinado del fibrinógeno y los títulos de estos anticuerpos tuvieron correlación con la actividad clínica en la enfermedad temprana. CONCLUSIONES: El inmunoanálisis diseñado con un péptido citrulinado del fibrinógeno tiene un alto valor diagnóstico y permite la identificación de pacientes con mayor actividad clínica en la AR temprana

OBJECTIVE: To determinate the diagnostic value of an antibody against a citrullinated fibrinogen peptide in Cuban patients with rheumatoid arthritis, using an enzyme immunasay. MATERIALS AND METHODS: A citrullinated peptide of fibrinogen designed by informatics prediction was synthesized and used in an enzyme immunoassay. The participants were 81 patients with early disease, 81 patients with established disease, 58 patients with other rheumatic and inflammatory diseases, and 43 healthy individuals. Anti- citrullinated fibrinogen peptide, anti-mutated citrullinated vimentin, anti second generation citrullinated peptides and rheumatoid factor antibodies were determined by enzyme-linked immunosorbent assay. RESULTS: Determination of anti-citrullinated peptide of fibrinogen antibodies by the designed enzyme immunoassay showed the best diagnostic value in early rheumatoid arthritis patients, with the highest value sensitivity (84%), negative predictive value (85%), Youden index (0.73%) and area under the receiver operating curve (0.9192). Specificity (89%) and positive predictive value (88%) were higher than rheumatoid factor, similar to anti- mutated citrullinated vimentin, but lower than second generation anti-citrullinated peptides assay. The positivity of C-reactive protein was associated with the presence of anti- citrullinated fibrinogen peptide antibodies and the titres of these antibodies correlated with clinical activity in early disease. CONCLUSIONS: The immunoassay designed with a citrullinated fibrinogen peptide has a high diagnostic value and can identify patients with greater clinical activity in early rheumatoid arthritis

Characterization of total adenosine deaminase activity (ADA) and its isoenzymes in saliva and serum in health and inflammatory conditions in four different species: an analytical and clinical validation pilot study.

BACKGROUND: Measurement of adenosine deaminase (ADA) can provide information about cell-mediated immunity. This report's objective was to study the enzymatic activity of total ADA (tADA) and its isoenzymes ADA1 and ADA2 in canine, equine, porcine, and bovine serum and saliva and their changes in different inflammatory situations in each species. Besides, an automated method for ADA2 measurement was developed and validated. RESULTS: tADA was present in serum and saliva of healthy animals of the four species. Erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) concentration of 0.47 mM was needed for ADA1 inhibition in canine and porcine samples (serum and saliva) and bovine saliva, whereas for equine saliva 0.94 mM was needed. ADA2 activity was not detected in bovine serum and was very low or absent in equine serum and bovine saliva. An automated procedure to measure ADA2 consisting of adding EHNA to a commercial reagent for tADA measurement provided repetitive (coefficients of variation < 8.8% in serum and < 10% in saliva) and accurate (linearity of serial sample dilutions with R2 > 0.90) results, being equivalent to a manual incubation of the sample with EHNA at a similar concentration. Salivary tADA, as well as ADA1 and ADA2, were higher in dogs with leishmaniosis, horses with acute abdominal disease and pigs with lameness than in healthy animals. tADA and isoenzymes in saliva showed a positive significant correlation with serum ferritin in dogs (r = 0.602, P < 0.01; r = 0.555, P < 0.05; and r = 0.632, P < 0.01; respectively for tADA, ADA1 and ADA2) and serum C-reactive protein in pigs (r = 0.700, P < 0.01, for both tADA and ADA1; r = 0.770, P < 0.001, for ADA2), whereas salivary ADA2 significantly correlated with serum amyloid A in horses (r = 0.649, P < 0.01). In cows, salivary tADA and ADA1 significantly increased after calving, correlating with total white blood cell count (r = 0.487, P < 0.05, for both tADA and ADA1). CONCLUSIONS: The activity of total ADA and its different isoenzymes, can be measured in serum and saliva of dogs, horses, pigs and cows by a simple and fast procedure described in this report. When measured in saliva, these analytes correlated with other biomarkers of inflammation and it could potentially be used as a biomarkers of inflammation and immune activation in the species of this study.

Usefulness of serum amylase and lipase as predictors of the severity of post-endoscopic retrograde cholangiopancreatography pancreatitis.

BACKGROUND: Post-ERCP pancreatitis (PEP) is the most common complication of Post-endoscopic retrograde cholangiopancreatography. OBJECTIVE: to demonstrate whether serum amylase and lipase values correlate with the presence and severity of PEP. METHOD: We conducted a retrospective, observational and analytical study of patients who underwent ERCP, those who developed pancreatitis were classified by severity according to the 2012 revised Atlanta criteria and their serum enzyme levels were analyzed. We used ROC (Receiver Operating Characteristics) curves to know the best enzyme cutoff points and analyzed their diagnostic yields. Chi-square, t-distribution and Mann-Whitney U test were used in the variable analysis and it was considered statistically significant when p < 0.05. RESULTS: A total 621 patients, 54 presented pancreatitis. For moderately severe and severe forms: lipase level of 1500 U/L had an area under the curve (AUC) = 0.827, 95% CI (0.67-0.98), sensitivity = 72.7%, specificity = 86%, negative predictive value = 92.5%, p < 0.05. Amylase level of 920 U/L presented AUC = 0.65, 95% CI (0.43-0.86), sensitivity = 63%, specificity = 67%, p > 0.05. CONCLUSIONS: Serum lipase shows correlation with the presence and severity of PEP. Amylase shows no significant correlation with PEP.

ANTECEDENTES: La pancreatitis poscolangiopancreatografía retrógrada endoscópica (PPCPRE) es la complicación más frecuente de este procedimiento. OBJETIVO: Demostrar si la amilasa y la lipasa séricas se correlacionan con la presencia y la gravedad de la PPCPRE. MÉTODO: Realizamos un estudio retrospectivo, observacional y analítico de pacientes a quienes se realizó CPRE. Los que desarrollaron pancreatitis se clasificaron por gravedad de acuerdo con la revisión de Atlanta de 2012 y se analizaron sus concentraciones séricas de enzimas. Empleamos curvas ROC (Receiver Operating Characteristics) para conocer los mejores puntos de corte enzimáticos y analizamos sus rendimientos diagnósticos. Usamos las pruebas de ji al cuadrado, t de Student y U de Mann Whitney para el análisis de las variables, y se consideró estadísticamente significativo un valor de p < 0.05. RESULTADOS: De un total de 621 pacientes, 54 presentaron pancreatitis. Para pancreatitis moderadamente grave y grave, unas cifras de lipasa de 1500 U/l presentaron un área bajo la curva (AUC) = 0.827 (intervalo de confianza del 95% [IC 95%]: 0.67-0.98), con una sensibilidad del 72.7%, una especificidad del 86% y un valor predictivo negativo del 92.5% (p < 0.05); y unas cifras de amilasa de 920 U/l presentaron un AUC = 0.65 (IC 95%: 0.43-0.86), con una sensibilidad del 63% y una especificidad del 67% (p > 0.05). CONCLUSIONES: La lipasa muestra correlación con la presencia y la gravedad de la PPCPRE. La amilasa muestra correlación no significativa con la PPCPRE.

First clinical assessment of a prototype assay to detect the enzymatic activity of ß-lactamase as a marker for pulmonary tuberculosis.

The objective was to evaluate the sensitivity and specificity of a novel prototype test, TB REaD™, a reporter enzyme fluorescence-based assay, for pulmonary tuberculosis and to determine the optimal threshold for test positivity. This blinded, prospective study enrolled 250 patients, of which 23.2% were Mycobacterium tuberculosis complex (MTB) culture-positive. At the manufacturer-set threshold, sensitivity of the assay was 93.1% (95% confidence interval [CI] 83.3-98.1) and specificity was 8.9% (95% CI 5.2-13.8). The highest accuracy was seen at a higher threshold: sensitivity 58.6% (95% CI 44.9-71.4), specificity 59.4% (95% CI 52.1%-66.4%), with sensitivity by smear status being 40.0% (95% CI 21.1-61.3) for smear-negative and 72.7% (95% CI 54.5-86.7) for smear-positive. This study demonstrated limited accuracy of the TB REaD™ prototype for detection of pulmonary TB. Further improvements are necessary, potentially exploring probes that are more specific to MTB.

Determination of diagnostic value (validity) leukocyte esterase (urine dipstick strip) in differentiating inflammatory arthritis from bacterial arthritis.

BACKGROUND: The current diagnostic cornerstone for septic arthritis contains gram stains, bacterial culture, and cell count with a differential of aspirated synovial fluid. Recently, a synovial leukocyte esterase (LE) test has been used for diagnosing septic arthritis. Since this test measures the esterase activity of leukocytes, there is always a dilemma for using this test in patients with inflammatory arthritis. METHODS: We collected the synovial fluid specimens as part of the general diagnostic protocol for patients suspected of Juvenile Idiopathic Arthritis (JIA) or Septic Arthritis (SA). Each group included 34 patients. We compared the result of the synovial LE test with the result of the culture of each patient. RESULTS: The mean ages of patients were 64.14 ± 31.27 and 50.88 ± 23.19 months in the JIA group and septic arthritis group, respectively. The LE test results were positive in 30 specimens, trace in 3 and negative in one in the first-time test and were positive in 31 specimens and trace in 3 in the second-time test, while it was negative in all patients with JIA. Hence, the sensitivity of the synovial LE test was 80.8%, the specificity, PPV, and NPV were 78.6, 70.0, 86.8% respectively based on a positive culture. CONCLUSION: The leukocyte esterase strip test can be used as a rapid, bedside method for diagnosing or excluding bacterial infections in different body fluids. The synovial LE test can be used as an accurate test to rapidly rule in or out an acute articular bacterial infection, even in patients with concurrent inflammatory arthritis.

Diagnostic Performance of C6 Enzyme Immunoassay for Lyme Arthritis.

OBJECTIVES: In Lyme disease endemic areas, initial management of children with arthritis can be challenging because diagnostic tests take several days to return results, leading to potentially unnecessary invasive procedures. Our objective was to examine the role of the C6 peptide enzyme immunoassay (EIA) test to guide initial management. METHODS: We enrolled children with acute arthritis undergoing evaluation for Lyme disease presenting to a participating Pedi Lyme Net emergency department (2015-2019) and performed a C6 EIA test. We defined Lyme arthritis with a positive or equivocal C6 EIA test result followed by a positive supplemental immunoblot result and defined septic arthritis as a positive synovial fluid culture result or a positive blood culture result with synovial fluid pleocytosis. Otherwise, children were considered to have inflammatory arthritis. We report the sensitivity and specificity of the C6 EIA for the diagnosis of Lyme arthritis. RESULTS: Of the 911 study patients, 211 children (23.2%) had Lyme arthritis, 11 (1.2%) had septic arthritis, and 689 (75.6%) had other inflammatory arthritis. A positive or equivocal C6 EIA result had a sensitivity of 100% (211 out of 211; 95% confidence interval [CI]: 98.2%-100%) and specificity of 94.2% (661 out of 700; 95% CI: 92.5%-95.9%) for Lyme arthritis. None of the 250 children with a positive or equivocal C6 EIA result had septic arthritis (0%; 95% CI: 0%-1.5%), although 75 children underwent diagnostic arthrocentesis and 27 underwent operative joint washout. CONCLUSIONS: In Lyme disease endemic areas, a C6 EIA result could be used to guide initial clinical decision-making, without misclassifying children with septic arthritis.

Leukocyte esterase strip test as a reliable intraoperative PJIs biomarker. Our experience.

ackgroud and aim of work: Prosthetic joint infection (PJI) is the most common cause of total knee replacement failure and the third most common cause of total hip replacement failure, accounting for 16.8% of all knee revisions and 14.8% of the hip revisions; nevertheless, the diagnosis of PJI is often a challenge for the orthopaedic surgeon. The aim of these study was to evaluate the reliability of the LE strip test for diagnosis of PJI. MATERIALS AND METHODS: From December 2016 to January 2019, we enrolled 50 patients with suspected PJI; 32 females and 18 males, the average age at the time of the surgery was 76 years. Twenty-four patients underwent knee revision surgery and twenty-six hip revision surgery. In all patients during the surgery, the synovial fluid was aspirated and used for leukocyte esterase strip test. The result of the tests was compared to periprosthetic tissues culture, histological examination and sonication fluid culture for PJI. RESULTS: Comparing the results obtained from the LE test with the results obtained from the other diagnostic methods, we found that the concordance between the results of the leukocyte-esterase test and those of the culture test with peri-prosthetic tissue or synovial fluid was shown to be 93%, between LE and histological examinations, the concordance was 93% and finally with the culture of the sonicated fluid the concordance was 86% of the cases. CONCLUSIONS: The results of our serie show a good intraoperative diagnostic accuracy of the LE test, especially in its ability to exclude the hypothesis of periprosthetic infection in case of a negative result.

Evaluation of quantitative biosensor for glucose-6-phosphate dehydrogenase activity detection.

Neonatal jaundice is a common and severe disease in premature infants with Glucose-6-Phosphate Dehydrogenase (G-6-PD) deficiency. The World Health Organization (WHO) has recommended screening for G-6-PD deficiency in newborns for early recognition as well as to prevent unwanted outcomes in a timely manner. The present study aimed to assess a point-of-care, careSTARTTM G6PD biosensor as a quantitative method for the diagnosis of G-6-PD deficiency. Factors influencing the evaluation of G-6-PD enzyme activity were examined in 40 adults, including ethylenediaminetetraacetic acid (EDTA) anticoagulant, hematocrit concentration, storage temperature and time. Analytic performance of the careSTARTTM G6PD biosensor was evaluated in 216 newborns and compared with fluorescent spot test (FST) and standard quantitative G-6-PD enzyme activity (SGT) assay. The results of factors affecting the G-6-PD enzyme activity showed that the activity determined from finger-prick was not statistically different from venous blood (p = 0.152). The G-6-PD value was highly dependent on the hematocrit and rose with increasing hematocrit concentration. Its activity was stable at 4°C for 3 days. Reliability analysis between the careSTARTTM G6PD biosensor and SGT assay showed a strong correlation with a Pearson's correlation coefficient of 0.82 and perfect agreement by intraclass correlation coefficient (ICC) of 0.90. Analysis of the area under the Receiver Operating Curve (AUC) illustrated that the careSTARTTM G6PD biosensor had 100% sensitivity, 96% specificity, 73% positive predictive value (PPV), 100% negative predictive value (NPV) and 97% accuracy at 30% of residual activity. While the diagnostic ability for identifying G-6-PD deficiency had 78% sensitivity, 89% specificity, 56% positive predictive value (PPV), 96% negative predictive value (NPV) and 88% accuracy when stratified by gender. The careSTARTTM G6PD biosensor is an attractive option as a point-of-care quantitative method for G-6-PD activity detection. Quantification of G-6-PD enzyme activity in newborns is the most effective approach for the management of G-6-PD deficiency to prevent severe jaundice and acute hemolysis.

Guía de práctica clínica multidisciplinar española sobre la enfermedad de Anderson-Fabry en adultos. I: Método y recomendaciones / Spanish multidisciplinary clinical practice guidelines for Anderson-Fabry Disease in Adults. I. Method and recommendations

La enfermedad de Anderson-Fabry es una afección multisistémica progresiva y grave de origen genético que afecta tanto a hombres como a mujeres y que reduce sus expectativas y calidad de vida. La gran variabilidad en su expresión clínica, las dificultades para su diagnóstico y la disponibilidad actual de varias alternativas para su tratamiento suponen un gran reto que justifica la realización de una guía de práctica clínica basada en la evidencia que pueda ayudar a los profesionales sanitarios en la toma de decisiones en el manejo de estos pacientes. Para elaborarla se ha realizado una búsqueda sistemática en las principales bases de datos bibliográficas mediante estrategias adaptadas a cada una de las 32 preguntas clínicas consideradas. Se confeccionaron fichas para la síntesis y evaluación de la calidad de las evidencias para cada una de las preguntas. La metodología empleada se basa en el Manual metodológico español para la elaboración de guías de práctica clínica e incorpora en la evaluación de la evidencia científica y en la elaboración de las recomendaciones la metodología GRADE, considerando la calidad de la evidencia, el balance entre beneficios y riesgos, valores y preferencias de los pacientes, equidad y uso de recursos. Para la elaboración definitiva de las recomendaciones se llevó a cabo un proceso de consenso estructurado basado en la metodología Delphi-RAND en 2 rondas, con un panel de expertos propuesto por diferentes sociedades científicas, centros de investigación y asociaciones de pacientes. Finalmente, se han elaborado 92 recomendaciones específicas para el manejo de la enfermedad de Fabry

Anderson-Fabry disease is a severe progressive multisystem condition of genetic origin that affects men and women, reducing their life expectancy and quality of life. The considerable variability in its clinical expression, the difficulties in diagnosing the condition and the current availability of several alternatives for its treatment represent a considerable challenge that justifies the development of evidence-based clinical practice guidelines that can help health professionals in the decision-making process for managing these patients. To develop these guidelines, we conducted a systematic search of the main reference databases using strategies adapted to each of the 32 clinical questions considered. We prepared documents to synthesise the evidence and assess its quality for each of the questions. The methodology employed is based on the Spanish methodology manual for preparing clinical practice guidelines, incorporating the GRADE methodology in the assessment of the scientific evidence and the preparation of the recommendations, considering the quality of the evidence, the risk-benefit balance, patient values and preferences, equity and use of resources. For the definitive preparation of the recommendations, we conducted a structured consensus process based on the Delphi-RAND methodology in 2 rounds, with an expert panel proposed by various scientific societies, research centres and patient associations. Ultimately, we developed 92 specific recommendations for managing Fabry disease

Species differences in lipoprotein lipase and hepatic lipase activities: comparative studies of animal models of lifestyle-related diseases.

Lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) have an important role in lifestyle-related diseases. To evaluate species differences, we compared LPL and HTGL activities in different animal models of lifestyle-related diseases using the same assay kit. Normal animals (JW rabbits, ICR mice, and SD rats), a hypercholesterolemic animal model (WHHLMI rabbits), and obese animal models (KK-Ay mice and Zucker fatty rats) fed standard chow were used in this study. Plasma was prepared before and after an intravenous injection of heparin sodium under fasting and feeding. LPL and HTGL activities were measured with the LPL/HTGL activity assay kit (Immuno-Biological Laboratories) using an auto-analyzer. Only in mice, high HTGL activity was observed in pre-heparin plasma. In normal animals, LPL and HTGL activities were high in ICR mice and SD rats but low in JW rabbits. Compared to normal animals, LPL activity was high in Zucker fatty rats and WHHLMI rabbits at both fasting and feeding, while LPL activity after feeding was low in KK-Ay mice. HTGL activity was higher in fasted and fed WHHLMI rabbits and fasted Zucker fatty rats, but was lower in fed KK-Ay mice. Gender difference was observed in HTGL activity in SD rats and LPL activity in WHHLMI rabbits but not in ICR mice. In conclusion, this simple assay method was effective for measuring LPL and HTGL activities of experimental animals, and the activities are highly regulated depending on animal species, animal models, feeding/fasting conditions and genders.

Systematic review on recent potential biomarkers of chronic obstructive pulmonary disease.

Introduction: Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death worldwide and associated with decreased lung function and inflammation. The heterogeneity of COPD and its molecular and clinical features hinder efficient patient stratification and introduction of personalized therapeutic approaches. The available clinical tools do not efficiently predict the progression and exacerbations of the disease. Areas covered: An overview of the most recent studies on putative COPD protein biomarkers and the challenges for implementing their use in the clinical setting is presented. Expert commentary: Proteomics biomarker discovery in COPD has mostly focused on approaches evaluating specific proteins on a limited number of samples. The most promising protein candidates can be classified into five main biological categories: extracellular matrix (ECM) remodeling, inflammation/immune response, oxidative stress response, vascular tone regulation, and lipid metabolism. To efficiently stratify COPD patients and predict exacerbations, it will be necessary to implement biomarker panels to better represent the complex pathophysiology of this disease. The application of unbiased proteomics and bioinformatics followed by appropriate clinical validation studies will contribute to the achievement of this aim while increasing the number of validated biomarkers that can enter the qualification processes by the regulatory entities.

Recent advances in histone modification and histone modifying enzyme assays.

Introduction: Histone modifying enzymes (HMEs)-catalyzed histone modifications are important epigenetic markers that play critical roles in the regulation of a variety of cellular functions, especially the regulation of gene expression. The aberrant histone modifying enzyme activity and the abnormal histone modification level are closely associated with various human diseases including cancers, making them become the promising and attractive disease biomarkers. Consequently, the development of efficient assays for accurate and sensitive detection of histone modifications and HMEs are crucial for disease diagnosis. Areas covered: In this review, we summarize the advances in histone modifications and HMEs assays in recent 5 years (2013-2018), including the development of various methods based on fluorescent, bioluminescent, colorimetric, electrochemical, surface-enhanced Raman scattering, and mass spectrometry strategies. Their principles and applications for in vitro and in vivo assays are reviewed, and the future directions are discussed as well. Expert commentary: In comparison with the conventional radioactive and Western blot assays, the newly developed histone modifications and HMEs assays exhibit distinct advantages. Especially, the introduction of novel nanomaterials and advanced analytical techniques in recent years has greatly improved the assay performances, promoting their further applications in biomedical research and clinical diagnosis.

Evaluation of a Novel Quantitative Test for Glucose-6-Phosphate Dehydrogenase Deficiency: Bringing Quantitative Testing for Glucose-6-Phosphate Dehydrogenase Deficiency Closer to the Patient.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency, a common genetic blood condition, can result in kernicterus at birth, and later in life as severe hemolysis on exposure to certain infections, foods, and drugs. The unavailability of point-of-care tests for G6PD deficiency is a barrier to routine curative treatment of Plasmodium vivax malaria with 8-aminoquinolines, such as primaquine. Two quantitative reference tests (Trinity Biotech, Bray, Ireland and Pointe Scientific, Canton, MI; Cat No. G7583) and the point-of-care STANDARD™ G6PD test (SD Biosensor, Suwon, South Korea) were evaluated. The STANDARD G6PD test was evaluated at multiple temperatures, in anticoagulated venous and capillary samples, including 79 G6PD-deficient and 66 intermediate samples and across two laboratories, one in the United States and one in Thailand. The STANDARD test performed equivalently to a reference assay for its ability to diagnose G6PD deficiency (< 30% normal) with a sensitivity of 100% (0.95 confidence interval [CI]: 95.7-100) and specificity of 97% (0.95 CI: 94.5-98.5), and could reliably identify females with less than 70% normal G6PD activity with a sensitivity of 95.5% (0.95 CI: 89.7-98.5) and specificity of 97% (0.95 CI: 94.5-98.6). The STANDARD G6PD product represents an opportunity to diagnose G6PD deficiency equally for males and females in basic clinical laboratories in high- and low-resource settings. This quantitative point-of-care diagnostic test for G6PD deficiency can provide equal access to safe radical cure of P. vivax cases in high- and low-resource settings, for males and females and may support malaria elimination, in countries where P. vivax is endemic.

Low Serum Pancreatic Amylase and Lipase Values Are Simple and Useful Predictors to Diagnose Chronic Pancreatitis.

Background/Aims: This study aimed to evaluate the diagnostic role of low serum amylase and lipase values in the detection of chronic pancreatitis. Methods: Patients underwent endoscopic retrograde cholangiopancreatography and were diagnosed with non-calcific chronic pancreatitis (NCCP; n=99) and calcific chronic pancreatitis (CCP; n=112). Patient serum amylase and lipase values were compared with those of healthy controls (H; n=170). Results: The median serum amylase (normal range, 19 to 86 U/L) and lipase values (7 to 59 U/L) (P25-P75) were 47.0 (39.8 to 55.3) and 25.0 (18.0 to 35.0) for H, 34.0 (24.5 to 49.0) and 19.0 (9.0 to 30.0) for NCCP, and 30.0 (20.0 to 40.8) and 10.0 (3.0 to 19.0) for CCP, respectively. The cutoff values with the highest diagnostic accuracy for discriminating NCCP from H were 40 U/L for amylase and 20 U/L for lipase, respectively, and for CCP from H were 38 U/L for amylase and 15 U/L for lipase, respectively. For the diagnosis of NCCP with a criterion of serum amylase <40 and lipase <20 U/L, the sensitivity, specificity, positive predictive value, and negative predictive values were 37.4%, 88.8%, 66.1%, and 70.9%, respectively. Conclusions: Serum amylase and/or lipase levels below the normal serum range are highly specific for chronic pancreatitis patients. Clinicians should not ignore low serum pancreatic enzyme values.

Postoperative changes of liver enzymes can distinguish between biliary stricture and graft rejection after living donor liver transplantation: A longitudinal study.

There is no known useful clinical parameter that can specifically predict a biliary stricture and differentiate it from other related complications after living donor liver transplantations (LDLT). The aims of this study were to determine whether the changes of liver enzymes can predict postoperative biliary stricture apart from other complications. We reviewed the medical records of 203 patients who underwent LDLT with duct to duct anastomosis from 2008 to 2010. The longitudinal changes of liver enzyme over time and the occurrence of complication were evaluated. A total of 124 patients had no complication up to 2 years after LDLT, and 74 patients had complications including biliary stricture and graft rejection. Complications developed more frequently in patients who's alkaline phosphatase (ALP) and gamma-glutamyl transpeptidase (GGT) did not return to the baseline plateau at 30 days after LDLT (ALP; P = .045, GGT; P = .047). Aspartate transaminase (AST) and alanine transaminase (ALT) increased continuously until the diagnosis of complication in both stricture and rejection groups with more rapid increase in enzymes in the rejection versus stricture group (P < .05). In addition, AST and ALT were 2-fold higher in the rejection than the stricture group at the diagnosis of each complication (AST; P < .05, ALT; P < .05). The increasing slope and final levels of AST and ALT are potentially helpful parameters to differentiate rejection and stricture, the 2 most common posttransplantation complications.