Total carotene plasma concentrations are inversely associated with atherosclerotic plaque burden: A post-hoc analysis of the DIABIMCAP cohort.

BACKGROUND AND AIMS: Atherosclerosis is the major risk factor for cardiovascular disease (CVD), the first cause of death worldwide. Chronic low-grade inflammation and a sustained oxidative milieu are causatively related to atherosclerosis onset and progression, and therefore, dietary patterns rich in bioactive compounds with anti-inflammatory and antioxidant activities might likely contribute to revert or slowing the progression of atherosclerosis. The aim of this study is to analyse the association between fruit and vegetables intake, quantitatively measured through carotene plasma concentrations, and atherosclerotic burden, as a surrogate biomarker of CVD, in free-living subjects from the DIABIMCAP cohort study. METHODS: The 204 participants of the DIABIMCAP Study cohort (Carotid Atherosclerosis in Newly Diagnosed Type 2 Diabetic Individuals, ClinicalTrials.gov Identifier: NCT01898572), were included in this cross-sectional study. Total, α-, and ß-carotenes were quantified by HPLC-MS/MS. Lipoprotein analysis in serum was performed by 2D- 1H NMR- DOSY, and atherosclerosis and intima media thickness (IMT) were measured through standardized bilateral carotid artery ultrasound imaging. RESULTS: Subjects with atherosclerosis (n = 134) had lower levels of large HDL particles than subjects without atherosclerosis. Positive associations were found between α-carotene and both large and medium HDL particles, and inverse associations were found between ß- and total carotene, and VLDL and its medium/small particles. Subjects with atherosclerosis presented significantly lower plasma concentrations of total carotene compared with subjects without atherosclerosis. Plasma concentrations of carotene decreased as the number of atherosclerotic plaques increased, although after multivariate adjustment, the inverse association between ß- and total carotene with plaque burden remained significant only in women. CONCLUSIONS: A diet rich in fruit and vegetables results in higher plasmatic carotene concentrations, which are associated with a lesser atherosclerotic plaque burden.

The Use of Corticosteroids or Tocilizumab in COVID-19 Based on Inflammatory Markers.

BACKGROUND: The inflammatory cascade is the main cause of death in COVID-19 patients. Corticosteroids (CS) and tocilizumab (TCZ) are available to treat this escalation but which patients to administer it remains undefined. OBJECTIVE: We aimed to evaluate the efficacy of immunosuppressive/anti-inflammatory therapy in COVID-19, based on the degree of inflammation. DESIGN: A retrospective cohort study with data on patients collected and followed up from March 1st, 2020, to May 1st, 2021, from the nationwide Spanish SEMI-COVID-19 Registry. Patients under treatment with CS vs. those under CS plus TCZ were compared. Effectiveness was explored in 3 risk categories (low, intermediate, high) based on lymphocyte count, C-reactive protein (CRP), lactate dehydrogenase (LDH), ferritin, and D-dimer values. PATIENTS: A total of 21,962 patients were included in the Registry by May 2021. Of these, 5940 met the inclusion criteria for the present study (5332 were treated with CS and 608 with CS plus TCZ). MAIN MEASURES: The primary outcome of the study was in-hospital mortality. Secondary outcomes were the composite variable of in-hospital mortality, requirement for high-flow nasal cannula (HFNC), non-invasive mechanical ventilation (NIMV), invasive mechanical ventilation (IMV), or intensive care unit (ICU) admission. KEY RESULTS: A total of 5940 met the inclusion criteria for the present study (5332 were treated with CS and 608 with CS plus TCZ). No significant differences were observed in either the low/intermediate-risk category (1.5% vs. 7.4%, p=0.175) or the high-risk category (23.1% vs. 20%, p=0.223) after propensity score matching. A statistically significant lower mortality was observed in the very high-risk category (31.9% vs. 23.9%, p=0.049). CONCLUSIONS: The prescription of CS alone or in combination with TCZ should be based on the degrees of inflammation and reserve the CS plus TCZ combination for patients at high and especially very high risk.

Baseline neuropsychological profiles in prion disease predict survival time.

OBJECTIVE: Few studies have captured the neuropsychological profile of sporadic Creutzfeldt-Jakob disease (sCJD) with neuropsychological testing, and little is known about cognitive predictors of survival. We characterized baseline neuropsychological performance in sCJD and investigated associations with survival. METHODS: sCJD participants who completed the MMSE (n = 118), 61 sCJD of whom also completed a neuropsychological battery at baseline, and 135 age-matched healthy controls, were included. Composite scores of global cognition, memory, executive functions, visuospatial, and language were derived. Cox proportional hazard models estimated survival time, controlling for age and education. Additional models adjusted for Barthel Index and PRNP codon 129 polymorphism. RESULTS: sCJD participants performed significantly worse than controls on all cognitive tasks and composites with most showing very large effect sizes. The three tests showing the largest group differences were delayed verbal recall (Hedges'g = 4.08, P < 0.0001), Stroop Inhibition (Hedges'g = 3.14, P < 0.0001), and Modified Trails (Hedges'g = 2.94, P < 0.0001). Memory (95%) and executive functioning (87%) composites were most commonly impaired. Poorer global (HR = 0.65, P < 0.0001), visuospatial (HR = 0.82, P < 0.0001), and memory (HR = 0.82, P = 0.01) composites predicted shorter survival. Visuospatial cognition remained a significant predictor even after adjusting for all other cognitive composites; each standard deviation decrease in visuospatial cognition was associated with an 18% higher chance of death (HR = 0.82, P < 0.003). Global (HR = 0.68, P = 0.03) and visuospatial (HR = 0.82, P = 0.001) composites remained significant predictors after controlling for Barthel Index and codon 129. INTERPRETATION: sCJD participants exhibit a broad range of cognitive impairments, with memory and executive functioning deficits in the vast majority. Neuropsychological assessment, particularly of visuospatial abilities, informs prognostication in sCJD.

5-cis-, Trans- and Total Lycopene Plasma Concentrations Inversely Relate to Atherosclerotic Plaque Burden in Newly Diagnosed Type 2 Diabetes Subjects.

Diabetic subjects are at increased risk of cardiovascular disease. Atherosclerosis, the common soil of most of the cardiovascular complications, is more prevalent and extensive in this population due not only to hyperglycemia, insulin resistance, and dyslipidemia, but also to inflammation and oxidative stress. Lycopenes are bioactive compounds with antioxidant and anti-inflammatory activities mostly supplied by tomato and tomato byproducts. We investigated the association between circulating lycopenes and carotid plaque burden in diabetic patients, in a cross-sectional study in 105 newly diagnosed diabetic subjects. Atheroma plaque (wall thickness ≥ 1.5 mm), number of plaques, and plaque burden (sum of maximum heights of all plaques) were assessed by sonographic evaluation of carotid arteries. Plasma lycopenes (5-cis-, 9-cis-, 13-cis-, and trans-lycopene) were quantified by high performance liquid chromatography-mass spectrometry HPLC-MS. Atheroma plaque was observed in 75 participants, from which 38 presented one plaque and 37 two or more carotid plaques. No differences were observed in the plasmatic concentrations of lycopenes between subjects with and without atherosclerotic plaque presence. However, plaque burden was inversely associated with 5-cis-lycopene, all cis-lycopene isomers, trans-lycopene, and total lycopene isomers (all, p < 0.05). High plasma levels of lycopenes inversely relate to atherosclerotic burden. We provide novel evidence that suggests that the consumption of compounds found in tomato and tomato byproducts might be beneficial for the prevention of atherosclerosis.

An informative nursing intervention for families of patients admitted to the intensive care unit regarding the satisfaction of their needs: The INFOUCI study.

AIM: To evaluate whether an informative intervention by nursing professionals through Short Message Service (SMS) improved patients' family members' satisfaction with the intensive care experience. METHODS/DESIGN: This was an exploratory, two-armed, randomised, non-pharmacological, prospective study. The intervention consisted of providing information to the contact persons of patients admitted to the ICU of the University Hospital La Princesa (Madrid, Spain) through SMS based on the patient's nursing assessment. Nursing diagnoses established by NANDA and based on the Virginia Henderson model were used as a reference. The main result was the satisfaction levels of the contacts of patients admitted to the intensive care unit, which was evaluated with the Critical Care Family Needs Inventory. RESULTS: The total score on the Critical Care Family Needs Inventory was significantly better in the intervention group (16.6 ±â€¯3.3 vs. 19.1 ±â€¯4.7; p = 0.012) compared with the control group. All participants included in the intervention considered it useful to some degree. Even when the contact person received negative information, there was no demand for information outside established hours, which was included as a possible adverse effect of the intervention. CONCLUSION: Support in the form of additional nursing information implied an increase in the satisfaction of the needs perceived by the contact persons of patients admitted to the intensive care unit, together with a better perception of the quality of intensive care unit care and a reassuring and beneficial effect.

Relationship between noninvasive scores of nonalcoholic fatty liver disease and nuclear magnetic resonance lipoprotein abnormalities: A focus on atherogenic dyslipidemia.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is an emerging, highly prevalent, cardiovascular risk factor, and lipoprotein proatherogenic disturbances likely explain a large part of this risk. However, information regarding associations between detailed nuclear magnetic resonance (NMR) lipoprotein changes and noninvasive NAFLD scores is lacking. OBJECTIVE: The objective of the study was to investigate the NMR-assessed atherogenic lipoprotein profile according to noninvasive NAFLD status. METHODS: Lipoprotein profiles by NMR spectroscopy and NAFLD status by fatty liver index (FLI) and Gholam's models. RESULTS: We assessed 173 participants (55% males), mean age 60.8 ± 7.8 years, 87% overweight/obese, 53% with diabetes. An FLI <30, 30 to 60, and >60 was found in 32, 50, and 91 participants, respectively. Individuals with FLI >60 had lower high-density lipoprotein (HDL)-cholesterol (P < .001), higher triglyceride (P < .001), and similar non-HDL-cholesterol (P = .912) concentrations. In NMR analysis, FLI was related with very-low-density lipoprotein (VLDL) and HDL parameters in a dose-dependent manner. VLDL particle number (P < .001) and VLDL size (39.1 ± 0.99, 39.7 ± 0.96, 40.8 ± 1.19 nm, P < .001) increased with increased FLI (<30, 30-60, and >60, respectively). Conversely, although total HDL particle number did not differ by FLI (P = .377), larger HDL particles (P < .001), amount of cholesterol within HDL particles (P < .001), and HDL size (median [p25-p75]: 8.23 [8.08-8.41], 8.12 [8.03-8.29], 8.04 [7.93-8.16] nm, P < .001) decreased as FLI increased. FLI >60 (vs <60) was associated with a higher proportion of small LDL particles (P = .010) and lower LDL size (19.85 ± 0.34 vs 19.98 ± 0.25 nm; P = .005). Similar findings were found for Gholam's model. CONCLUSION: Simple and noninvasive NAFLD scores are useful to detect many of the proatherogenic changes (especially in VLDL and HDL), beyond conventional lipids parameters that are common in individuals with this high-risk condition.

The proportion of total C18:1 trans-fatty acids in red blood cell membranes relates to carotid plaque prevalence.

Consistent evidence supports the pro-atherogenic properties of dietary trans-fatty acids (TFAs). However, there are no clinical data on TFA intake and atheroma plaque. We cross sectionally investigated whether the proportion of total C18:1 TFA in red blood cells (RBCs), which mirrors dietary TFA intake, independently relates to carotid plaque prevalence in subjects with new-onset type 2 diabetes mellitus without prior cardiovascular disease (n=101, 56% men, mean age 61 years) and age- and sex-matched controls (n=96). RBC fatty acid composition was determined by gas chromatography. Plaque (defined as carotid intima-media thickness ≥1.5 mm) was sonographically assessed at three bilateral carotid segments. In multivariate models adjusting for group (diabetes or control) and classical cardiovascular risk factors, for each 0.1% increase in RBC total C18:1 TFA isomers, plaque prevalence increased by 53% (P=.002). In contrast, for each 0.1% increase in RBC alpha-linolenic acid, the vegetable omega-3 fatty acid, plaque prevalence decreased by 43% (P<.001). We conclude that the RBC membrane proportion of total C18:1 TFA, considered a proxy of intake, directly relates to the ultrasound feature that best predicts future cardiovascular events. Our findings support current recommendations to limit TFA intake for cardiovascular health promotion.

Feasibility and Preliminary Outcomes of a Web and Smartphone-Based Medication Self-Management Platform for Chronically Ill Patients.

OBJECTIVE: The aim of this study was to assess the feasibility and preliminary outcomes of a medication self-management platform for chronically ill patients, Medplan. METHODS: We performed a 6-month single-arm prospective pre-post intervention study of patients receiving treatment for hypertension and/or dyslipidemia and/or heart failure and/or human immunodeficiency virus infection. During the pre-intervention phase, participants were followed according to their usual care; during the intervention phase, they used Medplan. We evaluated adherence, health outcomes, healthcare resources and measured the satisfaction of patients and health care professionals. RESULTS: The study population comprised 42 patients. No differences were found in adherence to medication measured by proportion of days covered with medication (PDC). However, when adherence was measured using the SMAQ, the percentage of adherent patients improved during the intervention phase (p < 0.05), and the number of days with missed doses decreased (p < 0.05). Adherence measured using the Medplan app showed poor concordance with PDC. No differences were found in health outcomes or in the use of health care resources during the study period. The mean satisfaction score for Medplan was 7.2 ± 2.7 out of 10 among patients and 7.3 ± 1.7 among health care professionals. In fact, 71.4 % of participants said they would recommend the app to a friend, and 88.1 % wanted to continue using it. CONCLUSION: The Medplan platform proved to be feasible and was well accepted by its users. However, its impact on adherence differed depending on the assessment method. The lack of effect on PDC is mainly because patients were already good adherers at baseline. The study enabled us to validate the platform in real patients using many different mobile devices and to identify potential barriers to scaling up the platform.

Nuclear magnetic resonance lipoprotein abnormalities in newly-diagnosed type 2 diabetes and their association with preclinical carotid atherosclerosis.

BACKGROUND AND AIMS: Atherogenic dyslipidemia is common in type 2 diabetes (T2DM) and predicts cardiovascular disease, but information on the association of its components with atherosclerosis is scarce. We aimed to assess differences in the lipoprotein profile in newly-diagnosed T2DM and matched control individuals and their associations with preclinical carotid atherosclerosis. METHODS: In a case-control study, we evaluated lipoprotein profiles by nuclear magnetic resonance (NMR) spectroscopy and determined carotid intima-media thickness (IMT) and plaque presence (IMT ≥1.5 mm) by B-mode ultrasonography. RESULTS: We assessed 96 T2DM patients (median age 63 years, 44% women, 19% smokers, 54% hypertension, 38% dyslipidemia) and 90 non-diabetic controls matched for age, sex, and cardiovascular risk factors. In T2DM VLDL-particles (mainly large and enriched in cholesterol and triglycerides) were increased, and large HDL-particles (enriched in triglycerides and depleted in cholesterol) were reduced (p < 0.05; all comparisons). Regarding associations with preclinical atherosclerosis, VLDL triglyceride content (odds ratio [OR], 8.975; 95% confidence interval [CI], 2.330-34.576), total number of VLDL particles (OR, 2.713; CI, 1.601-4.598) and VLDL size (OR, 2.044; CI, 1.320-3.166), and the ratio cholesterol/triglycerides in HDL (OR, 0.638; CI, 0.477-0.852) were associated with plaque burden (≥3 plaques) independently of confounders, including conventional lipid levels. CONCLUSION: NMR-assessed advanced lipoprotein profile identifies lipid abnormalities associated with newly-diagnosed T2DM and preclinical atherosclerosis that are not captured by the traditional lipid profile. At this early stage of diabetes, NMR lipoproteins could be useful to identify candidates for a more comprehensive cardiovascular risk prevention strategy.

Calidad del informe de alta hospitalaria realizado por médicos internos residentes de especialidades quirúrgicas / Quality of hospital discharge report conducted by surgical resident physicians

Introducción: Los médicos internos residentes (MIR) deben adquirir competencia en la correcta redacción del informe de alta hospitalaria (IAH). Este documento debe contener un conjunto de datos mínimos y ha de ser comprensible para el paciente, su médico de familia u otros profesionales. El proceso de adquisición de esta competencia ha sido poco estudiado y la calidad de los IAH firmados por MIR no se ha evaluado previamente. Sujetos y métodos: El presente estudio ha evaluado la calidad de 124 IAH de urgencias comparando aquellos firmados por especialistas, firmados únicamente por MIR o firmados por MIR y especialista, en las especialidades de cirugía ortopé- dica y traumatología y de cirugía general. Resultados: El resultado ha sido más favorable que el de publicaciones previas, con una puntuación superior a 7 sobre 10 en el 94,4% de los casos. Además, los IAH realizados por residentes de primer año y supervisados por especialistas han sido los informes con mejor puntuación, con diferencias estadísticamente significativas (p = 0,003). No se observaron diferencias estadísticamente significativas entre los informes redactados por la mañana respecto de los redactados por la madrugada (p = 0,6). En cuanto a los contenidos, un 12,9% de los informes presentaba siglas de difícil comprensión. Conclusión: Nuestro estudio objetiva el efecto beneficioso de la supervisión del IAH en el primer año de residencia, al igual que se identifica un objetivo de mejora consistente en minimizar el uso de siglas médicas

Introduction: Resident intern physicians (MIR) must become competent in writing correct hospital discharge reports (HDR). This document must contain a minimum data set, and should be understandable to the patient, family doctor or other professionals. The acquisition of this competence has been little studied, and the quality of HDRs performed by MIR has not been previously evaluated. Subjects and methods: The present study evaluated the quality of 124 emergency HDRs comparing those signed by specialists, only signed or signed by MIR, or signed by MIR and specialist in the fields of Orthopaedic Surgery and General Surgery. Results: The result has been more favourable than that of previous publications, with a score of 7 out of 10 in 94.4 % of cases. HDRs made by first-year residents and supervised by specialists obtained the best scores with statistically significant differences (p = 0.003). No differences were observed between the reports by the morning or night (p = 0.6). In terms of content, 12.9% of reports had acronyms difficult to understand. Conclusion: Our study depicts the beneficial effect of HDR monitoring in the first year of residency as well as an improvement objective by minimizing the use of medical abbreviations

Linkage and association analyses using families identified a locus affecting an osteoporosis-related trait.

Osteoporosis is a common disorder characterized by low bone mass and microarchitectural deterioration of bone tissue, resulting in an increase in bone fragility and in susceptibility to fractures. The genetic basis of osteoporosis is complex and involves multiple genes and environmental factors. Here we introduce a family-based study of the genetics of osteoporosis - the Genetic Analysis of Osteoporosis (GAO) Project - to discover genetic variants affecting osteoporosis-related phenotypes. The GAO Project involved 11 extended families from Barcelona, Spain selected through a proband with osteoporosis (N=367). We performed spine, femur and whole body densitometry for all participants and also analyzed strength and geometrical properties of the hip. Our study focused on 23 densitometric phenotypes that we considered of high clinical relevance and four definitions of low bone mass and fracture status. Pedigree validation was carried out through microsatellite genotyping. The same microsatellites were used to interrogate our data (i) for the replication of previous linkage signals and (ii) for the potential discovery of new linkage signals. The linkage analysis identified one region marked by microsatellite D17S787 showing a strong and significant signal of linkage with femoral shaft cross-sectional moment of inertia (CSMI; LOD=3.18; p=6.5×10(-5)). The chromosomal location marked by microsatellite D17S787 includes several genes, among which two are of particular interest: COL1A1 and SOST, coding for collagen alpha-1 (I) chain and sclerostin, respectively. Follow-up association analysis resulted in only one significant result for rs4792909 from the SOST genomic region (p=0.00248). As a result, we provide strong and significant evidence from both linkage and association analyses that the SOST gene may affect the strength of the femoral shaft. Future investigations should study the relationship between bone mass formation and strength properties of the bones.

Linfoma gástrico primario / The conservative treatment with anthracycline containing chemotherapy has replaced gastrectomy as a standard approach against primary gastric lymphoma

El estómago constituye la localización más frecuente del linfoma no-Hodgkin extranodal. El linfoma difuso de células grandes B es el tipo histológico predominante. Es un linfoma agresivo que inicialmente se presenta como enfermedad localizada asociada o no a la infección con Helicobacter pylori. El tratamiento conservador con regímenes quimioterápicos con antraciclina seguidos o no por radioterapia en campos comprometidos ha reemplazado a la gastrectomía como tratamiento de primera línea.

The stomach is the extranodal site most commonly involved by non-Hodgkin lymphomas. Diffuse large B-cell lymphoma is the most common histotype category arising in this organ. This is an aggressive lymphoma usually presenting as limited disease, being associated or not to Helicobacter pylori infection. Conservative treatment with anthracycline-containing chemotherapy, followed or not by involved-field radiotherapy has replaced gastrectomy as standard approach against this malignancy.

Rituximab, 2a línea de tratamiento en leucemia de células vellosas / Rituximab 2nd line of treatment for hairy cell leukemia

La leucemia de células vellosas (LCV) es un desorden linfoproliferativo crónico caracterizado por: esplenomegalia, pancitopenia con linfocitos vellosos e infiltración de médula ósea y de bazo. Rituximab demuestra eficacia terapéutica y en pacientes con LCV refractaria/recaída.

Inmunoquimioterapia en linfoma no Hodgkin indolente (LNHI) / Immunochemotherapy for non-hodkin indolent lyphomas

Actualmente esta bien establecido que la asociación de Rituximab (R) con quimioterapia (QT), inmunoquimioterapia, aumento la sobreviva global en pacientes (pts.) con LNHI.

Rol de las plaquetas en la hemostasia / The role of the platelets in hemostasis

Luego de la injuria del vaso sanguíneo, las plaquetas son activadas, cambian su forma discoide a esférica y se adhieren al endotelio expuesto por un proceso denominado adhesión. Este proceso involucra la interacción de un componente plasmático, el FvW, y una glicoproteína específica de membrana, la GPIb, sobre la superficie plaquetaria. La adhesión es seguida por el reclutamiento de plaquetas adicionales que se adhieren entre sí (proceso denominado agregación). Este proceso comprende, entre otros elementos, la unión del fibrinógeno a receptores plaquetarios específicos GP IIb y IIIa. La adhesión y agregación comprometen la interacción con las proteínas (FG y FvW) que están presentes en el plasma y en los gránulos alfa. Las plaquetas activadas liberan el contenido de sus gránulos, por un proceso llamado secreción. Esto libera sustancias como el ADP, que pueden causar activación adicional de plaquetas. La interacción de las plaquetas con sus agonistas produce una serie de fenómenos que preceden a respuestas como la agregación o secreción. Una de las respuestas plaquetarias más tempranas es la activación de la fosfolipasa C, llevando a la hidrólisis del fosfatidilinositol y a la generación de mensajeros moleculares como el IP3y el DG. El IP3 media el aumento de la concentración del calcio ionizado en la plaqueta, lo cual se considera un factor regulador en varias respuestas plaquetarias como la movilización mediada por fosfolipasa A2 de AA libre, desde los fosfolípidos unidos a la membrana y la fosforilación de la cadena liviana de miosina, que está involucrada en la secreción plaquetaria. El DG activa a la proteinquinasa C, la cual produce la fosforilación de una proteína de 47 kD. Esta se sabe que tiene un rol sinérgico con la movilización de calcio intracelular. Otra respuesta a la estimulación plaquetaria es la liberación de AA de los fosfolípidos de la membrana y su oxigenación a tromboxano A2 por las enzimas cicloxigenasa y tromboxano sintetasa. De este modo la activación plaquetaria termina en la formación y liberación de sustancias activantes (ejemplos: ADP y TXA2), los cuales producen un mecanismo de feed-back positivo, que amplifica el proceso de activación. El rol más importante de las plaquetas en la hemostasia es su contribución a la activación de la cascada de coagulación y los fenómenos que conducen a la generación de trombina. Varias reacciones enzimáticas de la coagulación ocurren sobre la superficie plaquetaria...

Rol de las plaquetas en la hemostasia / The role of the platelets in hemostasis

Luego de la injuria del vaso sanguíneo, las plaquetas son activadas, cambian su forma discoide a esférica y se adhieren al endotelio expuesto por un proceso denominado adhesión. Este proceso involucra la interacción de un componente plasmático, el FvW, y una glicoproteína específica de membrana, la GPIb, sobre la superficie plaquetaria. La adhesión es seguida por el reclutamiento de plaquetas adicionales que se adhieren entre sí (proceso denominado agregación). Este proceso comprende, entre otros elementos, la unión del fibrinógeno a receptores plaquetarios específicos GP IIb y IIIa. La adhesión y agregación comprometen la interacción con las proteínas (FG y FvW) que están presentes en el plasma y en los gránulos alfa. Las plaquetas activadas liberan el contenido de sus gránulos, por un proceso llamado secreción. Esto libera sustancias como el ADP, que pueden causar activación adicional de plaquetas. La interacción de las plaquetas con sus agonistas produce una serie de fenómenos que preceden a respuestas como la agregación o secreción. Una de las respuestas plaquetarias más tempranas es la activación de la fosfolipasa C, llevando a la hidrólisis del fosfatidilinositol y a la generación de mensajeros moleculares como el IP3y el DG. El IP3 media el aumento de la concentración del calcio ionizado en la plaqueta, lo cual se considera un factor regulador en varias respuestas plaquetarias como la movilización mediada por fosfolipasa A2 de AA libre, desde los fosfolípidos unidos a la membrana y la fosforilación de la cadena liviana de miosina, que está involucrada en la secreción plaquetaria. El DG activa a la proteinquinasa C, la cual produce la fosforilación de una proteína de 47 kD. Esta se sabe que tiene un rol sinérgico con la movilización de calcio intracelular. Otra respuesta a la estimulación plaquetaria es la liberación de AA de los fosfolípidos de la membrana y su oxigenación a tromboxano A2 por las enzimas cicloxigenasa y tromboxano sintetasa. De este modo la activación plaquetaria termina en la formación y liberación de sustancias activantes (ejemplos: ADP y TXA2), los cuales producen un mecanismo de feed-back positivo, que amplifica el proceso de activación. El rol más importante de las plaquetas en la hemostasia es su contribución a la activación de la cascada de coagulación y los fenómenos que conducen a la generación de trombina. Varias reacciones enzimáticas de la coagulación ocurren sobre la superficie plaquetaria... (AU)