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.

[Epidemiologic monitoring system for the diabetic patient; use of computerized technology in the quality of medical care]. / Sistema de vigilancia epidemiológica para el paciente diabético; el uso de tecnología computacional en la calidad de la atención médica.

OBJECTIVE: To describe an instrument for epidemiologic surveillance of diabetes mellitus and evaluating the quality of care in primary health care. MATERIAL AND METHODS: The study was conducted from January 1, 1998, to June 30, 1999, at the Epidemiology and Health Services Research Unit of the Mexican Institute for Social Security (IMSS), in Hermosillo, Sonora. A single data collection form was designed, which contains items included in the diabetes care clinic of the Unit of Family Medicine of the Mexican Institute of Social Security. RESULTS: We developed and implemented a software program to enter data from the paper format and to generate individual and group reports on attendance to scheduled medical visits, medical history, evolution of signs and symptoms, laboratory tests, and medication. CONCLUSIONS: Electronic data systems allow the availability of reliable and continuing information for surveillance of the comprehensive care of the diabetic patient.

[Role of embryonal steroidogenesis in early pregnancy]. / Papel de la esteroidogénesis embrionaria en el embarazo temprano.

Recent studies, have shown that pre-implanted embryos of several species synthesize steroid hormones: progesterone, progestins , androgens and several estrogens and it has been postulated that oviductal and endometrial functions are influenced by blastocyst synthesis and release of these molecules. Steroids may create an appropriate milieu for blastocyst migration, nutrition, development and implantation in the maternal uterus. It is the purpose of this paper to review a possible physiological role of steroid hormonal synthesis by the early embryo during the first stages of pregnancy.

Evidence for a role of brain thyrotropin-releasing hormone (TRH) on stress gastric lesion formation in rats.

Specific polyclonal antibodies raised against synthetic thyrotropin-releasing hormone (TRH) infused intracerebroventricularly (ICV) significantly decreased gastric lesions induced by cold restraint stress. The antiulcer effect of immunologic blockade of brain TRH was specific. Normal rabbit serum or antibodies raised against somatostatin, alpha-MSH, Leu-enkephalin, gonadotropin-releasing hormone and atrial natriuretic factor were ineffective. These findings suggest that brain TRH may play an important role in experimental stress ulcer formation.

Imipramine prevents gastric lesions induced by centrally administered thyrotropin-releasing hormone (TRH) in rats.

Increasing evidence indicates that thyrotropin-releasing hormone (TRH), and endogenous brain-gut peptide may play a role in experimental ulcerogenesis. Potential interactions between TRH and imipramine (a typical tricyclic antidepressant (TCA] on the development of TRH-induced gastric lesions have not been investigated. Imipramine (0.05, 0.5 and 5 mg/kg, i.p.) dose-dependently inhibited gastric lesion formation induced by intracisternal (i.c.) administration of TRH (1 micrograms). In addition, imipramine (5 mg/kg, i.p.) significantly decreased gastric acid secretion in response to i.c. TRH (1 microgram) in rats with pyloric ligation. These findings suggest the TCAs may be effective drug agents against centrally initiated gastric ulcerations. The mechanism of this response probably involves blockade of cholinergic (muscarinic) and H2 histamine receptors.