Valor diagnóstico de anticuerpos anti Helicobacter pylori en pacientes referidos al Servicio de Endoscopía Digestiva del Hospital San Vicente de Paul, Costa Rica

Artículo científico -- Universidad de Costa Rica, Instituto de Investigaciones en Salud. 2002Antibodies titers against H. pylori antigens were determined in 78 patients referred to the Digestive Endoscopy Service of the San Vicente de Paul Hospital, Costa Rica. The assay was performed by enzyme immunoassay (ELISA), using commercial and non comercial methods with costarrican bacterial antigens and antigens prepared in Sweden, with the purpose of determining the diagnostic sensitivity and specificity of IgG, IgM and IgA inmunoglobulines. Material and methods. The commercial ELISA method was performed according to instructions and the two ELISA methods were prepared in the laboratory using no commercial antigens, one from Costa Rica and the other prepared in Sweden. Results. H pylori infection was present in 83% of studied patients. The determination of IgG anti H. pylori by commercial ELISA method presents the highest diagnostic sensitivity (76%) and the non commercial ELISA using costarrican antigen shows the lowest diagnostic sensitivity (57%) with the highest diagnostic specificity (92%). The non commercial ELISA method more specific was the one that uses costarrican bacterial antigen, but the antigen prepared in Sweden had the highest sensitivity (67%). Discussion. The use of antigens prepared of local strains permits the detection of the presence of H. pylori with greater confidence as compared to ntigens prepared with strains from other regions, because elevated serologic tests are high suggestive of the presence of the bacteria in the gastric mucous. The anti H. pylori inmunoglobulin with the highest diagnostic sensitivity and specificity was the IgG, but a histologic study of gastric biopsy instead of using the serologic test alone is recommended for the diagnosis of H. pylori.Introducción. El estudio se realizó en 78 pacientes referidos al Servicio de Endoscopia Digestiva del Hospital San Vicente de Paul, un estudio de anticuerpos sericos anti H. pylori tipo IgG, IgM e IgA por el método de ELISA utilizando antígenos comerciales y preparados con bacterias autóctonas, a fin de determinar la sensibilidad diagnostica y la especificidad diagnostica de cada inmunoglobulina. Material y métodos. Se utilizo un método de ELISA comercial y dos métodos de ELISA preparados en el laboratorio utilizando antígenos no comerciales, uno de origen costarricense y otro preparado en Suecia. Resultados. El 83% de los pacientes presentaron infección por H. pylori. En la determinación de IgG anti H. pylori el método de ELISA comercial presentó la sensibilidad diagnostica más altas (76%) mientras que el método de ELBA no comercial con antígeno de origen costarricense presento la sensibilidad diagnostica más baja (57%), pero con la mayor especificidad diagnóstica (92%). El método de ELISA no comercial más especifico fue el que utiliza antígeno de origen costarricense, sin embargo el antígeno de origen sueco mostro mayor sensibilidad (67%). Conclusiones. El use de antígenos autóctonos permite detectar la presencia de H. pylori con mayor confianza que los foráneos, ya que una prueba serológica aumentada es altamente sugestiva de la presencia de la bacteria en la mucosa gástrica. La inmunoglobulina anti H. pylori con mejor sensibilidad y especificidad diagnostica fue la IgG, pero se recomienda realizar un estudio.Universidad de Costa Rica. Instituto de Investigaciones en Salud.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA

Decreased Erythrocyte CCS Content is a Biomarker of Copper Overload in Rats

Copper (Cu) is an essential trace metal that is toxic in excess. It is therefore important to be able to accurately assess Cu deficiency or overload. Cu chaperone for Cu/Zn superoxide dismutase (CCS) protein expression is elevated in tissues of Cu-deficient animals. Increased CCS content in erythrocytes is particularly sensitive to decreased Cu status. Given the lack of a non-invasive, sensitive and specific biomarker for the assessment of Cu excess, we investigated whether CCS expression in erythrocytes reflects Cu overload. Rats were fed diets containing normal or high levels of Cu for 13 weeks. Diets contained 6.3 ± 0.6 (Cu-N), 985 ± 14 (Cu-1000) or 1944 ± 19 (Cu-2000) mg Cu/kg diet. Rats showed a variable response to the high Cu diets. Some rats showed severe Cu toxicity, while other rats showed no visible signs of toxicity and grew normally. Also, some rats had high levels of Cu in liver, whereas others had liver Cu concentrations within the normal range. Erythrocyte CCS protein expression was 30% lower in Cu-2000 rats compared to Cu-N rats (P < 0.05). Notably, only rats that accumulated high levels of Cu in liver had lower erythrocyte CCS (47% reduction, P < 0.05) compared to rats fed normal levels of Cu. Together, these data indicate that decreased erythrocyte CCS content is associated with Cu overload in rats and should be evaluated further as a potential biomarker for assessing Cu excess in humans

Cuantificación espectrofotométrica del cloruro en suero mediante reacción con tiocianato de mercurio

El anión que se encuentra en mayor concentración en el fluido extracelular es el ion cloruro (i) (2), por lo que juega un papel importante en regular la distribución del agua, la presión osmótica y el balance aniónico-catiónico (2). Los métodos más usados actualmente para la cuantificación de cloruro en suero, se fundamentan en la poca solubilidad que presentan las sales de cloruro de plata (3-5) y en la baja ionización de las sales de cloruro de mercurio (7-9). Los métodos titrimétricos par a el análisis de cloruro en fluidos biológicos, se basan en la titulación manual con nitrato de mercurio (S) (JO) y en la titulación coulométrica-amperométrica (11). Otros tipos de técnicas incluyen la dilución isotópica (12), la del electrodo ion selectivo (13) y las técnicas colorimétricas que utilizan reactivos libres de mercurio (14). Las desventajas del método titrimétrico manual, radican en la lentitud y en la poca reproducibilidad causada por la subjetividad en la detección del punto final de la titulación.UCR::Vicerrectoría de Docencia::Salud::Facultad de Microbiologí

Truncating mutations in the Wilson disease gene ATP7B are associated with very low serum ceruloplasmin oxidase activity and an early onset of Wilson disease

<p>Abstract</p> <p>Background</p> <p>Mutations in the gene ATP7B cause Wilson disease, a copper storage disorder with a high phenotypic and genetic heterogeneity. We aimed to evaluate whether 'severe' protein-truncating ATP7B mutations (SMs) are associated with low serum ceruloplasmin oxidase activities and an early age of onset when compared to missense mutations (MMs).</p> <p>Methods</p> <p>The clinical phenotype of 59 genetically confirmed WD patients was analyzed retrospectively. Serum ceruloplasmin was measured by its oxidase activity with <it>o</it>-dianisidine dihydrochloride as substrate and immunologically.</p> <p>Results</p> <p>Thirty-nine patients had two MMs, 15 had the genotype SM/MM, and 5 patients had two SMs on their ATP7B alleles. Enzymatic and immunologic serum ceruloplasmin levels differed significantly between the three groups (P < 0.001 and P < 0.01, respectively). The lowest levels were measured in patients with two SMs (0.0 U/L; IQR, 0.0-0.0 U/L and 0.02 g/L; IQR, 0.01-0.02 g/L, respectively) and the highest in patients with two MMs (17.8 U/L; IQR, 5.8-35.1 U/L and 0.11 g/L; IQR,0.10-0.17 g/L, respectively). The age of onset was also significantly different between the three patient groups (P < 0.05), with SM/SM patients showing the earliest onset (13 years; IQR, 9-13 years) and patients with two MMs showing the latest onset (22 years; IQR, 14-27 years). By ROC curve analysis a ceruloplasmin oxidase level ≤ 5 U/L can predict the presence of at least one SM with a sensitivity of 80% and a specificity of 79.5%.</p> <p>Conclusions</p> <p>In our German study cohort truncating ATP7B mutations were associated with lower ceruloplasmin serum oxidase levels and an earlier age of onset when compared to MMs. Measurement of serum ceruloplasmin oxidase might help to predict presence of truncating ATP7B mutations and might facilitate the mutation analysis.</p

In Absence of the Cellular Prion Protein, Alterations in Copper Metabolism and Copper-Dependent Oxidase Activity Affect Iron Distribution

Essential elements as copper and iron modulate a wide range of physiological functions. Their metabolism is strictly regulated by cellular pathways, since dysregulation of metal homeostasis is responsible for many detrimental effects. Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and prion diseases are characterized by alterations of metal ions. These neurodegenerative maladies involve proteins that bind metals and mediate their metabolism through not well-defined mechanisms. Prion protein, for instance, interacts with divalent cations via multiple metal-binding sites and it modulates several metal-dependent physiological functions, such as S-nitrosylation of NMDA receptors. In this work we focused on the effect of prion protein absence on copper and iron metabolism during development and adulthood. In particular, we investigated copper and iron functional values in serum and several organs such as liver, spleen, total brain and isolated hippocampus. Our results show that iron content is diminished in prion protein-null mouse serum, while it accumulates in liver and spleen. Our data suggest that these alterations can be due to impairments in copper-dependent cerulopalsmin activity which is known to affect iron mobilization. In prion protein-null mouse total brain and hippocampus, metal ion content shows a fluctuating trend, suggesting the presence of homeostatic compensatory mechanisms. However, copper and iron functional values are likely altered also in these two organs, as indicated by the modulation of metal-binding protein expression levels. Altogether, these results reveal that the absence of the cellular prion protein impairs copper metabolism and copper-dependent oxidase activity, with ensuing alteration of iron mobilization from cellular storage compartments

Early stage transplantation of bone marrow cells markedly ameliorates copper metabolism and restores liver function in a mouse model of Wilson disease

<p>Abstract</p> <p>Background</p> <p>Recent studies have demonstrated that normal bone marrow (BM) cells transplantation can correct liver injury in a mouse model of Wilson disease (WD). However, it still remains unknown when BM cells transplantation should be administered. The aim of this study was to investigate the potential impact of normal BM cells transplantation at different stages of WD to correct liver injury in toxic milk (tx) mice.</p> <p>Methods</p> <p>Recipient tx mice were sublethally irradiated (5 Gy) prior to transplantation. The congenic wild-type (DL) BM cells labeled with CM-DiI were transplanted via caudal vein injection into tx mice at the early (2 months of age) or late stage (5 months of age) of WD. The same volume of saline or tx BM cells were injected as controls. The DL donor cell population, copper concentration, serum ceruloplasmin oxidase activity and aspartate aminotransferase (AST) levels in the various groups were evaluated at 1, 4, 8 and 12 weeks post-transplant, respectively.</p> <p>Results</p> <p>The DL BM cells population was observed from 1 to 12 weeks and peaked by the 4^thweek in the recipient liver after transplantation. DL BM cells transplantation during the early stage significantly corrected copper accumulation, AST across the observed time points and serum ceruloplasmin oxidase activity through 8 to 12 weeks in tx mice compared with those treated with saline or tx BM cells (all <it>P </it>< 0.05). In contrast, BM cells transplantation during the late stage only corrected AST levels from 4 to 12 weeks post-transplant and copper accumulation at 12 weeks post-transplant (all <it>P </it>< 0.05). No significant difference was found between the saline and tx BM cells transplantation groups across the observed time points (<it>P </it>> 0.05).</p> <p>Conclusions</p> <p>Early stage transplantation of normal BM cells is better than late stage transplantation in correcting liver function and copper metabolism in a mouse model of WD.</p

Copper Chaperone for Cu/Zn Superoxide Dismutase is a sensitive biomarker of mild copper deficiency induced by moderately high intakes of zinc

BACKGROUND: Small increases in zinc (Zn) consumption above recommended amounts have been shown to reduce copper (Cu) status in experimental animals and humans. Recently, we have reported that copper chaperone for Cu/Zn superoxide dismutase (CCS) protein level is increased in tissues of overtly Cu-deficient rats and proposed CCS as a novel biomarker of Cu status. METHODS: Weanling male Wistar rats were fed one of four diets normal in Cu and containing normal (30 mg Zn/kg diet) or moderately high (60, 120 or 240 mg Zn/kg diet) amounts of Zn for 5 weeks. To begin to examine the clinical relevance of CCS, we compared the sensitivity of CCS to mild Cu deficiency, induced by moderately high intakes of Zn, with conventional indices of Cu status. RESULTS: Liver and erythrocyte CCS expression was significantly (P < 0.05) increased in rats fed the Zn-60 and/or Zn-120 diet compared to rats fed normal levels of Zn (Zn-30). Erythrocyte CCS expression was the most sensitive measure of reduced Cu status and was able to detect a decrease in Cu nutriture in rats fed only twice the recommended amount of Zn. Liver, erythrocyte and white blood cell CCS expression showed a significant (P < 0.05) inverse correlation with plasma and liver Cu concentrations and caeruloplasmin activity. Unexpectedly, rats fed the highest level of Zn (Zn-240) showed overall better Cu status than rats fed a lower level of elevated Zn (Zn-120). Improved Cu status in these rats correlated with increased duodenal mRNA expression of several Zn-trafficking proteins (i.e. MT-1, ZnT-1, ZnT-2 and ZnT-4). CONCLUSION: Collectively, these data show that CCS is a sensitive measure of Zn-induced mild Cu deficiency and demonstrate a dose-dependent biphasic response for reduced Cu status by moderately high intakes of Zn

Liver-Specific Commd1 Knockout Mice Are Susceptible to Hepatic Copper Accumulation

Canine copper toxicosis is an autosomal recessive disorder characterized by hepatic copper accumulation resulting in liver fibrosis and eventually cirrhosis. We have identified COMMD1 as the gene underlying copper toxicosis in Bedlington terriers. Although recent studies suggest that COMMD1 regulates hepatic copper export via an interaction with the Wilson disease protein ATP7B, its importance in hepatic copper homeostasis is ill-defined. In this study, we aimed to assess the effect of Commd1 deficiency on hepatic copper metabolism in mice. Liver-specific Commd1 knockout mice (Commd1Δhep) were generated and fed either a standard or a copper-enriched diet. Copper homeostasis and liver function were determined in Commd1Δhep mice by biochemical and histological analyses, and compared to wild-type littermates. Commd1Δhep mice were viable and did not develop an overt phenotype. At six weeks, the liver copper contents was increased up to a 3-fold upon Commd1 deficiency, but declined with age to concentrations similar to those seen in controls. Interestingly, Commd1Δhep mice fed a copper-enriched diet progressively accumulated copper in the liver up to a 20-fold increase compared to controls. These copper levels did not result in significant induction of the copper-responsive genes metallothionein I and II, neither was there evidence of biochemical liver injury nor overt liver pathology. The biosynthesis of ceruloplasmin was clearly augmented with age in Commd1Δhep mice. Although COMMD1 expression is associated with changes in ATP7B protein stability, no clear correlation between Atp7b levels and copper accumulation in Commd1Δhep mice could be detected. Despite the absence of hepatocellular toxicity in Commd1Δhep mice, the changes in liver copper displayed several parallels with copper toxicosis in Bedlington terriers. Thus, these results provide the first genetic evidence for COMMD1 to play an essential role in hepatic copper homeostasis and present a valuable mouse model for further understanding of the molecular mechanisms underlying hepatic copper homeostasis

Preclinical Evaluation of Caprylic Acid-Fractionated IgG Antivenom for the Treatment of Taipan (Oxyuranus scutellatus) Envenoming in Papua New Guinea

articulo (arbitrado) -- Universidad de Costa Rica, Instituto de Investigaciones Clodomiro Picado, 2011Background: Snake bite is a common medical emergency in Papua New Guinea (PNG). The taipan, Oxyuranus scutellatus, inflicts a large number of bites that, in the absence of antivenom therapy, result in high mortality. Parenteral administration of antivenoms manufactured in Australia is the current treatment of choice for these envenomings. However, the price of these products is high and has increased over the last 25 years; consequently the country can no longer afford all the antivenom it needs. This situation prompted an international collaborative project aimed at generating a new, low-cost antivenom against O. scutellatus for PNG. Methodology/Principal Findings: A new monospecific equine whole IgG antivenom, obtained by caprylic acid fractionation of plasma, was prepared by immunising horses with the venom of O. scutellatus from PNG. This antivenom was compared with the currently used F(ab’)2 monospecific taipan antivenom manufactured by CSL Limited, Australia. The comparison included physicochemical properties and the preclinical assessment of the neutralisation of lethal neurotoxicity and the myotoxic, coagulant and phospholipase A2 activities of the venom of O. scutellatus from PNG. The F(ab’)2 antivenom had a higher protein concentration than whole IgG antivenom. Both antivenoms effectively neutralised, and had similar potency, against the lethal neurotoxic effect (both by intraperitoneal and intravenous routes of injection), myotoxicity, and phospholipase A2 activity of O. scutellatus venom. However, the whole IgG antivenom showed a higher potency than the F(ab’)2 antivenom in the neutralisation of the coagulant activity of O. scutellatus venom from PNG. Conclusions/Significance: The new whole IgG taipan antivenom described in this study compares favourably with the currently used F(ab’)2 antivenom, both in terms of physicochemical characteristics and neutralising potency. Therefore, it should be considered as a promising low-cost candidate for the treatment of envenomings by O. scutellatus in PNG, and is ready to be tested in clinical trials.This study was supported by Vicerrectoría de Investigación, Universidad de Costa Rica (project 741-A9-003); the PNG Office of Higher Education, CTP Limited (Milne Bay Estates), and the Australian Venom Research Unit (University of Melbourne), which is funded by the Australian Government Department of Health and Ageing, the Australia Pacific Science Foundation and Snowy Nominees. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP