Biomedical point-of-care microanalyzer for potentiometric determination of ammonium ion in plasma and whole blood

Acord transformatiu CRUE-CSICSome inborn errors of metabolism and other diseases can result in increasing blood ammonium (hyperammonemia episodes), which can cause serious neurological complications in patients or even death. Early diagnosis, follow up and treatment are essential to minimize irreversible damages in brain. Currently, adequate analytical instrumentation for the necessary ammonium bedside determination is not available in all health centers but only in clinical laboratories of reference hospitals. We therefore have developed a low cost and portable potentiometric Point-of-Care microanalyzer (POC) to address this problem. It consists of a cyclic olefin copolymer-based microanalyzer, the size of a credit card and working in continuous flow, which integrates microfluidics, a gas-diffusion module and a potentiometric detection system. The analytical features achieved are a linear range from 30 to 1000 μmol L NH , a detection limit of 18 μmol L NH and a required sample volume of 100 μL, which comply with the medical requirements. Plasma and blood samples are analyzed with no significant differences observed between ammonium concentrations obtained with both the proposed microanalyzer and the reference method. This demonstrates the value of the developed POC for bedside clinical applications

Cerebrospinal fluid neopterin analysis in neuropediatric patients: establishment of a new cut off-value for the identification of inflammatory-immune mediated processes.

ObjectiveA high level of cerebrospinal fluid (CSF) neopterin is a marker of central nervous system inflammatory-immune mediated processes. We aimed to assess data from 606 neuropediatric patients, describing the clinical and biochemical features of those neurological disorders presenting CSF neopterin values above a new cut-off value that was defined in our laboratory.MethodsTo establish the new CSF neopterin cut-off value, we studied two groups of patients: Group 1 comprised 68 patients with meningoencephalitis, and Group 2 comprised 52 children with a confirmed peripheral infection and no central nervous system involvement. We studied 606 CSF samples from neuropediatric patients who were classified into 3 groups: genetic diagnosis (A), acquired/unknown etiologic neurologic diseases (B) and inflammatory-immune mediated processes (C).ResultsThe CSF neopterin cut-off value was 61 nmol/L. Out of 606 cases, 56 presented a CSF neopterin level above this value. Group C had significantly higher CSF neopterin, protein and leukocyte values than the other groups. Sixteen of twenty-three patients in this group had a CSF neopterin level above the cut-off, whereas three and seven patients presented increased leukocyte and protein values, respectively. A significant association was found among CSF neopterin, proteins and leukocytes in the 606 patients. White matter disturbances were associated with high CSF neopterin concentrations.ConclusionsAlthough children with inflammatory-immune mediated processes presented higher CSF neopterin values, patients with other neurological disorders also showed increased CSF neopterin concentrations. These results stress the importance of CSF neopterin analysis for the identification of inflammatory-immune mediated processes

CSF biochemical values from subjects with CNS infections and peripheral infections.

<p>*Significant values were observed in Total Group 1 vs Total Group 2 (U-Mann Whitney test). The data for the CSF variables are shown as median and range in brackets. CSF: cerebrospinal fluid, WBC: white blood cells.</p

Patients with CSF neopterin levels below 61/l (n = 550).

<p>Out of 550 patients with CSF neopterin levels below 61 nmol/l, 68 patients had altered CSF proteins, and nine had altered CSF leucocytes. CSF NP: cerebrospinal fluid neopterin. The results are shown as the median and interval in brackets.</p

ROC curve to determine the new CSF neopterin cut-off.

<p>The samples were classified into two groups according to the condition that they presented either bacterial/viral central infection (n = 68) or peripheral infection (n = 52). The area under the curve was 0.934 (range: 0.883–0.985) with 61 nmol/l as the new cut-off. The sensitivity was 91.3%, and the specificity was 88.5%.</p

Representation of the 606 neurological patients in the clinical groups.

<p>Each group shows the percentage of patients with high CSF WBC, high CSF proteins and high CSF neopterin. The inflammatory/immune-mediated group had a significantly elevated percentage of high CSF WBC (^*X² = 27.91, p<0.001), high CSF proteins (^ΨX² = 17.51, p<0.001) and high CSF NP (^ΦX² = 103.73, p<0.001) compared with the other groups.</p

Patients with CSF neopterin levels above 61/l (n = 56).

<p>*Inflammatory/immune-mediated group had significantly elevated CSF neopterin (X² = 35.01, p<0.001), CSF proteins (X² = 12.71, p = 0.002) and CSF leukocytes (X² = 6.23, p = 0.044) compared with the other groups. Moreover, up to 69.6% of the patients more frequently had CSF NP>61 nmol/L. Out of 56 patients with a CSF neopterin level above 61 nmol/l, 13 patients had altered CSF proteins and four had altered CSF leucocytes.</p><p>AGS: Aicardi-Goutières syndrome; ARCI: arthrogryposis, renal tubular dysfunction, cholestasis, ichthyosis syndrome; anti-NMDA encephalitis: anti-(N-methyl D-aspartate) receptor encephalitis; CINCA: chronic infantile neurological, cutaneous and articular syndrome; VLCAD: very long-chain acyl-CoA dehydrogenase; CSF NP: cerebrospinal fluid neopterin; WBC: white blood cells. Dist: disturbances. The results are shown as the median and interval in brackets.</p

Verbeia: Journal of english and spanish studies Nº2

Verbeia nace con la finalidad de contagiarnos con la pasión de la Filología. Durante este año hemos crecido, nuestro Comité Científico aumenta y con él las esperanzas de estabilidad. Todos sabemos lo que cuesta llegar hasta aquí, y hoy llegamos con artículos escritos por profesores e investigadores de distintas universidades del planeta