Clot activators and anticoagulant additives for blood collection. A critical review on behalf of COLABIOCLI WG-PRE-LATAM.

In the clinical laboratory, knowledge of and the correct use of clot activators and anticoagulant additives are critical to preserve and maintain samples in optimal conditions prior to analysis. In 2017, the Latin America Confederation of Clinical Biochemistry (COLABIOCLI) commissioned the Latin American Working Group for Preanalytical Phase (WG-PRE-LATAM) to study preanalytical variability and establish guidelines for preanalytical procedures to be applied by clinical laboratories and health care professionals. The aim of this critical review, on behalf of COLABIOCLI WG-PRE-LATAM, is to provide information to understand the mechanisms of the interactions and reactions that occur between blood and clot activators and anticoagulant additives inside evacuated tubes used for laboratory testing. Clot activators - glass, silica, kaolin, bentonite, and diatomaceous earth - work by surface dependent mechanism whereas extrinsic biomolecules - thrombin, snake venoms, ellagic acid, and thromboplastin - start in vitro coagulation when added to blood. Few manufacturers of evacuated tubes state the type and concentration of clot activators used in their products. With respect to anticoagulant additives, sodium citrate and oxalate complex free calcium and ethylenediaminetetraacetic acid chelates calcium. Heparin potentiates antithrombin and hirudin binds to active thrombin, inactivating the thrombin irreversibly. Blood collection tubes have improved continually over the years, from the glass tubes containing clot activators or anticoagulant additives that were prepared by laboratory personnel to the current standardized evacuated systems that permit more precise blood/additive ratios. Each clot activator and anticoagulant additive demonstrates specific functionality, and both manufacturers of tubes and laboratory professional strive to provide suitable interference-free sample matrices for laboratory testing. Both manufacturers of in vitro diagnostic devices and laboratory professionals need to understand all aspects of venous blood sampling so that they do not underestimate the impact of tube additives on laboratory testing.

Ivermectin reduces in vivo coronavirus infection in a mouse experimental model.

The objective of this study was to test the effectiveness of ivermectin for the treatment of mouse hepatitis virus (MHV), a type 2 family RNA coronavirus similar to SARS-CoV-2. Female BALB/cJ mice were infected with 6,000 PFU of MHV-A59 (group infected, n = 20) or infected and then immediately treated with a single dose of 500 µg/kg ivermectin (group infected + IVM, n = 20) or were not infected and treated with PBS (control group, n = 16). Five days after infection/treatment, the mice were euthanized and the tissues were sampled to assess their general health status and infection levels. Overall, the results demonstrated that viral infection induced typical MHV-caused disease, with the livers showing severe hepatocellular necrosis surrounded by a severe lymphoplasmacytic inflammatory infiltration associated with a high hepatic viral load (52,158 AU), while mice treated with ivermectin showed a better health status with a lower viral load (23,192 AU; p < 0.05), with only a few having histopathological liver damage (p < 0.05). No significant differences were found between the group infected + IVM and control group mice (P = NS). Furthermore, serum transaminase levels (aspartate aminotransferase and alanine aminotransferase) were significantly lower in the treated mice than in the infected animals. In conclusion, ivermectin diminished the MHV viral load and disease in the mice, being a useful model for further understanding this therapy against coronavirus diseases.

Differences in Cryptococcus neoformans capsular polysaccharide structure influence assembly of alternative complement pathway C3 convertase on fungal surfaces.

Binding of complement component C3 and Factor B to Cryptococcus neoformans serotypes A through D via the alternative complement pathway was measured in a system containing fresh nonimmune human serum. Serotypes B and C (C. neoformans var. gattii) bound approximately half as many molecules of both complement components as serotypes A and D (C. neoformans var. neoformans). In contrast, removal of xylosyl and glucuronyl side chains from the mannan main chain of capsular polysaccharide by the Smith degradation procedure resulted in binding of similar quantities of C3 to each of the four serotypes. We conclude that the relatively high degree of side chain substitution of capsular polysaccharide from C. neoformans variety gattii contributes to inefficient surface assembly of the alternative pathway C3 convertase. Inefficient binding of alternative pathway complement components to serotypes B and C may contribute to the relative difficulty in successfully treating infections caused by these organisms.

HLA-DR antigens in Mexican patients with Guillain-Barré syndrome.

The distribution of HLA-DR antigens was investigated in 38 Mexican Mestizo patients with Guillain-Barré syndrome (GBS) and in 100 healthy controls belonging to the same population. IgG, IgM, IgA, CH50, C3, C4 and the number of T and B lymphocytes were also evaluated in the patients. Only DR3 was significantly increased in the patients (Yates' chi 2 = 9.943, Pc = 0.014) and the relative risk for developing the disease was 3.49. These findings support the hypothesis that DR3 or a closely linked Ir gene may play some role in the susceptibility to GBS.

Study of an Argentine mistletoe, the hemiparasite Ligaria cuneifolia (R. et P.) Tiegh. (Loranthaceae).

Ligaria cuneifolia (R. et P.) Tiegh. is an hemiparasite species used in Argentine folk medicine as a substitute for the European mistletoe (Viscum album L.) based on its putative activity of decreasing high blood pressure. This paper analyzes flavonoid composition, protein constituents and the possible immunomodulatory and antitumoral effects of this species. Micromolecular study disclosed quercetin-free, quercetin-glycosylated and proanthocyanidins corresponding to cyanidin monomers, which implies a particular metabolic pathway. Proteins present in L. cuneifolia extracts analyzed by SDS-PAGE presented multiple bands with molecular weights ranging from 14 to 90 kD. These features contribute to the characterization of the native mistletoe. As V. album is being used in cancer treatment due to its immunomodulatory and antitumoral activity, the action of aqueous L. cuneifolia extracts on murine lymphocytes was investigated. Culture of murine spleen cells alone or stimulated with Concanavalin A or lipopolysaccharide in presence of L. cuneifolia extracts indicated a certain stimulation of splenocytes alone and an inhibition of splenocytes stimulated with Concanvalin A or lipopolysaccharide. An inhibitory effect was also observed on the proliferation of murine leukemia cells. In addition, aqueous extracts increased nitric oxide production by murine macrophages. These results suggest that L. cuneifolia extracts exert an immunomodulatory effect on the mouse immune system.

Adaptive monitoring in the ICU: a dynamic and contextual study.

The wealth of physiological data made available by current medical monitoring systems can be used efficiently only if the monitoring system is capable of relieving human personnel of relatively low-level tasks by performing intelligent data interpretation, contextual analysis and advice tasks. The system described in this paper can choose the variables to which most processing time will be devoted on the basis of the evolution of the patient.

Modifications in the classification of primary myelodysplastic syndromes: the addition of a scoring system.

A retrospective series of patients with the primary myelodysplastic syndrome has been reviewed and the survival updated. A scoring system is proposed that has advantages in predicting survival outcome. The importance of either dysmegakaryocytopoiesis or dysgranulocytopoiesis is emphasized because of its prognostic impact on leukaemic progression. Over 50 per cent of the patients die from either acute leukaemia or consequences of defective marrow production of granulocytes and platelets. Although only a few cases were included, the RAEB-T group has a very poor outcome and appears much closer to FAB M2 in biologic behaviour than RAEB. Both the criteria for the FAB subtypes and the scoring system can be applied easily in each case of myelodysplasia. Of the 56 patients only 9 were still alive as of April, 1984. Eight of these were in the RA-S and RA categories (or using the scoring system grouping 7 were group 1). All of the 16 patients who progressed to overt AML died within 4 weeks, and none was treated with chemotherapy. Of the remaining 31 patients, half died as a result of infection and/or haemorrhage and the remainder from apparently unrelated causes (cardiovascular, carcinoma, renal failure). These latter deaths are not surprising in light of the median age of 72 years.

Enterotoxigenic and enteropathogenic Escherichia coli in Galicia (north-west Spain).

We have studied the incidence of enterotoxigenic and enteropathogenic Escherichia coli strains associated with infant diarrhoeal disease in Galicia (North-west Spain). During a period of 9 months we isolated heat-labile enterotoxin-positive strains in 2.1% of children with diarrhoea examined, whereas the production of heat-stable enterotoxin was detected in 1.1% of them. Enteropathogenic strains were isolated from 5.3% of the children with diarrhoea, but none of these strains released heat-labile or heat-stable enterotoxins.

[Pharmacological therapy compliance in diabetes]. / Apego al tratamiento farmacológico en pacientes con diagnóstico de diabetes mellitus tipo 2.

OBJECTIVE: To establish the frequency of compliance to pharmacological therapy, and to identify non-compliance factors, in relation to metabolic control on patients with type-II diabetes mellitus. MATERIAL AND METHODS: A comparative cross-sectional study was conducted between 1997 and 1998, among 150 type-II diabetic patients, at the Family Medicine Unit No. 33, of the Mexican Institute of Social Security, in Chihuahua, Mexico. Compliance to drug therapy was measured by counting tablets at home. Metabolic control was measured through glycosilated hemoglobin. A questionnaire was given to collect data on factors related to compliance. Statistical analysis consisted of descriptive statistics, Student's t and odds ratios. RESULTS: Pharmacological therapy compliance was 54.2%. Factors associated with non-compliance were elementary schooling and lack of information about the disease. CONCLUSIONS: Pharmacological therapy compliance was low. Factors related to non-compliance can be modified through education.

Promotion of hepatocellular foci in female rats by chenodeoxycholic acid.

Chenodeoxycholic acid (CDC), a dihydroxylated primary bile acid, was evaluated for promotional activity in the liver of rats using a two-stage initiation-promotion model. CDC is a primary bile acid that can attain high concentrations in serum and liver during induced or naturally occurring hepatocellular disorders. Female Sprague-Dawley rats were injected once (i.p.) with diethylnitrosamine (DEN, 150 mg/kg) or sterile physiologic saline (SAL, 0.85% NaCl). Two weeks later, rats in each group were placed into one of two subgroups and fed either NIH-31 mash (Control) or NIH-31 mash containing 0.5% CDC for a 10 week period. At the end of the feeding period, blood and liver samples were collected for determination of bile acid profiles and quantitation of hepatocellular foci respectively. Serum samples were analyzed for concentrations of individual bile acids using a HPLC method that utilizes a post-column enzymatic reaction and fluorescence detection. Liver slices from the left hepatic lobe were stained for foci positive for placental glutathione S-transferase. In serum, significant increases occurred in concentrations of all forms of CDC and were accompanied by mild, insignificant increases in lithocholic acid. Decreased serum concentrations occurred in all forms of cholic and deoxycholic acids. Analysis of liver sections revealed that rats treated with DEN-CDC had significant increases in numbers and volume of foci compared to those treated with DEN-Control. For rats in groups DEN-CDC and DEN-Control, the numbers of foci per square centimeter were 32 and 12; per cubic centimeter, 2221 and 937; and the per cent volume of foci, 1.487 and 0.385 respectively. In this study, CDC was a promoter of hepatocellular foci. Because concentrations of CDC in liver and serum increase in a variety of hepatobiliary disorders, the possibility that increases in endogenous concentrations can enhance the formation of hepatocellular foci is being explored.

Aspergillus fumigatus complement inhibitor: production, characterization, and purification by hydrophobic interaction and thin-layer chromatography.

Aspergillus fumigatus has previously been shown to produce a soluble extracellular inhibitor of the alternative complement pathway, called Aspergillus complement inhibitor, or CI. We now report an efficient method for production of CI which relies on the fact that poorly conidiating cultures yielded CI activity with approximately sevenfold-higher potency than CI produced by conidiating cultures. CI from poorly conidiating cultures provided 50% inhibition of alternative pathway-mediated binding of 125I-labeled complement component C3 to cryptococcal blastoconidia at a mean concentration of 60 micrograms/ml. The ability of crude CI to inhibit the alternative complement pathway seemed to be independent of intact protein or polysaccharide structure, as evidenced by resistance of inhibitory activity to digestion by proteases, including subtilisin, alpha-chymotrypsin, papain, and pepsin as well as endoglycosidases F and H. Separation of the active inhibitory component of CI from contaminating materials contained in crude CI preparations was achieved by using Phenylsuperose hydrophobic interaction chromatography in a fast protein liquid chromatography system. The active material proved to be extremely hydrophobic, desorbing from the column only during elution with ethanol; it contained only 15% protein and 5% polysaccharide. Furthermore, results from preparative thin-layer chromatography indicated that lipids which comigrated with phosphatidylserine/phosphatidylinositol and phosphatidylethanolamine possessed significant complement-inhibitory activity. Taken together, these data suggested that phospholipids from A. fumigatus contributed to the functional activity of CI.

Duplicación gástrica / Gastric duplication

Introducción: La duplicación gástrica es una malformación poco frecuente del tubo digestivo, que en algunos casos puede dar sintomatología secundaria a una complicación. Objetivo: Reportar dos pacientes portadores de una duplicación gástrica que fueron resueltos por vía laparoscópica. Se detallan los aspectos clínicos, radiológicos y los beneficios de la técnica utilizada. Casos: Un lactante de 9 meses portador de una neurofibromatosis que en su estudio abdominal aparece como hallazgo una malformación quística del estómago, y un recién nacido que presenta vómitos frecuentes, dolor abdominal y masa palpable. Ambos tratados con cirugía laparoscópica, con buena evolución. Conclusión: La duplicación gástrica es una entidad poco frecuente que requiere tratamiento quirúrgico, ya sea por vía abierta o laparoscópica, siendo esta última una técnica recomendable y segura en la actualidad.

Estenosis traqueal congénita, Serie clínica / Congenital tracheal stenosis

Introducción: La estenosis traqueal congénita (ETC) es una entidad clínica infrecuente, que se caracteriza por la presencia de anillos traqueales circulares completos, que determinan estrechez fija del lumen traqueal ocasionando dificultad respiratoria de grado variable. Objetivos: Comunicar 10 pacientes portadores de ETC, sus aspectos clinicos, morfológicos y alternativas en el tratamiento. Pacientes y Método: Se analizó retrospectivamente las formas de manifestación, exámenes diagnósticos y evolución de diez pacientes portadores de ETC diagnosticados entre los años 1998 y 2006. Resultados: Seis pacientes con síntomas respiratorios graves requirieron cirugía correctora de la traquea, uno falleció luego de un año, en el postoperatorio de una intervención cardiovascular. Cuatro pacientes con sintomatología respiratoria menor no requirieron corrección quirúrgica, uno falleció en el postoperatorio de una cirugía cardiaca. Conclusión: La ETC es una malformación potencialmente grave que requiere tratamiento quirúrgico en los pacientes sintomáticos con obstrucción severa de vía aérea. Los pacientes con síntomas leves pueden permanecer en control y no ser sometidos a cirugía correctora.

Congenital tracheal stenosis (CTS) constitutes an uncommon disease, characterized by the presence of complete tracheal rings that determine a fixed narrow tracheal lumen with different levels of respiratory distress. Objective: To expose 10 patients with CTS in relation to their morphological-clinical aspects and treatment alternatives. Method: Retrospective analysis of these patients diagnosed with CTS between 1998 and 2006, in terms of clinical evolution and diagnostic exams. Results: 6 patients with severe respiratory symptoms needed corrective tracheal surgery; one of them died one year later during cardiac surgery. 4 patients with mild respiratory symptoms did not require tracheal surgery; one of them died during cardiac surgery. Conclusion: CTS is a serious malformation that requires surgical treatment in those patients with severe airway obstruction. Patients with mild symptoms are observed closely without the need for surgery.

Pulmón esofágico: caso clínico / Esophageal lung: a case-report

Introducción: El pulmón esofágico es una malformación congénita muy infrecuente que se produce por una alteración en el desarrollo normal del intestino anterior. Consiste en la presencia de tejido pulmonar conectado con el esófago. Clínicamente se puede manifestar como neumonías recurrentes, dificultad respiratoria o disnea que aparece junto con la alimentación. Objetivo: Reportar el primer paciente portador de esta malformación tratado en nuestra institución. Caso Clínico: Lactante masculino, 4 meses de edad, con neumonías recurrentes del lóbulo superior derecho. El estudio con imágenes y endoscopía, confirmó la presencia de un pulmón supernumerario que estaba comunicado con el tercio medio del esófago. El paciente fue sometido a una resección quirúrgica de la malformación. Evoluciona favorablemente con mejoría de sintomatología. Conclusión: El pulmón esofágico es una malformación poco frecuente que debe ser sospechada en pacientes con sintomatología respiratoria recurrente. El estudio con imágenes y endoscopía permite precisar el diagnóstico.

Hendidura esternal total en un recién nacido y parcial en una niña de 4 años / Cleft sternum: 2 clinical cases

La hendidura esternal es una malformación congénita de la pared torácica que se origina en una falla embrionaria de la fusión de las valvas esternales en la línea media. El defecto debe ser reparado precozmente al nacer, para reestablecer la protección ósea de las estructuras del mediastino, prevenir el movimiento paradojal de las vísceras en la respiración, eliminar la deformidad visible y permitir un desarrollo normal de la caja torácica. Objetivo: Notificar 2 pacientes portadores de esta infrecuente malformación y revisar sus características clínicas, permitiendo realizar un diagnostico preciso, orientar el estudio y definir un adecuado tratamiento. Casos clínicos: Recién nacido masculino con una hendidura esternal completa que provoca un "distress" respiratorio y una preescolar de 4 años, con una hendidura parcial del tercio superior esternal, asociada a una cardiopatía congénita operada. Los pacientes son sometidos a una reparación quirúrgica que permitió un alta precoz y una evolución clínica favorable. Conclusión: La Hendidura Esternal es una malformación de baja frecuencia que debe ser corregida precozmente para evitar el uso de técnicas de mayor complejidad con resultados variables.

Registro continuado por 24 horas del pH esofágico en el diagnóstico de reflujo gastroesofágico en niños / Continuous register by 24 hours of the esophageal pH in gastroesophageal reflux diagnosis in children

El registro continuado del pH esofágico en 24 h. es el método funcional más objetivo para el estudio delreflujo gastroesofágico, pues permite determinar la exposición esofágica al ácido y correlacionar diversos síntomas con el reflujo, siendo la pesquisa del reflujo oculto una de las principales indicaciones. La estandarización propuesta por la Sociedad Europea de Gastroenterología y Nutrición Pediátrica (ESPGAN) ha sido un gran aporte para uniformar la interpretación y comunicación de resultados entre diferentes agrupaciones clínicas