Evidence for respiratory viruses interactions in asymptomatic preschool-aged children

Aim

To prospectively evaluate interferences between viruses of the upper respiratory tract in asymptomatic preschool children.

Platelet injury during phototherapy

Phototherapy with blue fluorescent light is widely employed for treatment of neonatal hyperbilirubinemia. Functional, biochemical, and morphologic changes produced by blue fluorescent light in human platelets were identified and characterized. Platelet-rich plasma was exposed for up to 170 min to amounts of light equivalent to that used in phototherapy of neonatal hyperbilirubinemia. Within 110 min of light exposure, platelets were essentially no longer aggregable by ADP and connective tissue suspension and were depleted of ADP, ATP, and glycogen. Electron photomicrographs revealed these platelets to be swollen, depleted of glycogen granules and organelles, and to have ill-defined membranes. Platelet injury could be accelerated by adding a photosensitizing agent, hematoporphyrin, to platelet samples before exposure. In contrast, control platelets kept in the dark for 170 min or nonirradiated platelets resuspended in irradiated plasma maintained their integrity. The results indicate that platelets are damaged in vitro when exposed to amounts of blue light used in phototherapy.     

Platelet interaction with bacterial toxins and secreted products

Abstract

Bacteria that enter the bloodstream will encounter components of the cellular and soluble immune response. Platelets contribute to this response and have emerged as an important target for bacterial pathogens. Bacteria produce diverse extracellular proteins and toxins that have been reported to modulate platelet function. These interactions can result in complete or incomplete platelet activation or inhibition of platelet activation, depending on the bacteria and bacterial product. The nature of the platelet response may be highly relevant to disease pathogenesis.     

Platelet count correlates with stage and predicts survival in melanoma

Cancer is a chronic inflammatory state which is often associated with increased platelet counts. Cancer cells induce thrombopoiesis and activate platelets, which in turn facilitate cancer invasion and metastasis. In this study, we investigate the correlation between platelet counts with each of stage and overall survival in melanoma. This is a retrospective cohort study of 642 melanoma patients diagnosed or treated at a tertiary medical center between 2000 and 2016. Multivariable analysis adjusted for age, sex, stage, and treatment modality. Using multivariable analysis, patients with thrombocytosis around time of diagnosis were more likely to present with distant metastasis (Prevalence Ratio 3.5, 95% CI 2.35–5.22). In patients with metastatic disease and in all stages combined, thrombocytosis predicted decreased 5-year overall survival in univariate and multivariable analysis, and this was most pronounced during the first year after diagnosis. Finally, we show that mice with thrombocytopenia due to the lack of heat shock protein gp96 in their megakaryocytes are protected from melanoma dissemination to the lungs. These findings are concordant with preclinical studies showing a role for platelets in cancer metastasis and suppression of antitumor immunity, further supporting targeting platelets as an adjuvant to immunotherapy in melanoma.     

血小板在缺血性脑卒中患者中的研究进展

缺血性脑卒中指大脑供血动脉闭塞或狭窄使脑供血不足而导致的脑组织不同程度受损,主要由动脉粥样硬化及继发血栓形成引起,而血小板在血栓形成过程中发挥着重要作用。缺血性脑卒中的治疗主要以血小板为靶点,但因个体用药依从性差异和缺血性脑卒中高复发等特点,部分缺血性脑卒中患者即使进行了规范的抗血小板治疗但仍存在再发脑卒中风险。本文主要对缺血性脑卒中患者抗血小板治疗、血小板参数及其检测方法进行了综述,以期为再发脑卒中的预防及监测提供参考。     

Platelet – von Willebrand factor interactions in Type IIB von Willebrand's disease

Type IIB von Willebrand's disease (vWD) is a distinct form of this disorder in which the largest multimers of the von Willebrand factor (vWF) are lacking in plasma but present in platelets. When the vasopressin analogue, l-deamino-8-D-arginine vasopressin (DDAVP), is given to patients with type IIB vWD, an abnormal vWF is released to plasma. This vWF causes thrombocytopenia in vivo and platelet aggregation in vitro. Aggregation occurs in the plasma milieu and thus at physiological fibrinogen concentration. In this study we demonstrate that IIB post-DDAVP vWF aggregated only metabolically active platelets. The platelet aggregation was completely inhibited by EDTA and PGE₁, and either inhibited or greatly weakened by ASA, demonstrating the role of divalent cations and thromboxane A₂ formation. In spite of inhibiting platelet aggregation, EDTA, PGE₁ and ASA did not prevent platelet binding of IIB post-DDAVP vWF. An antiserum against GP Ib made normal platelets less responsive to the IIB vWF although neither platelet aggregation nor vWF binding were completely prevented. The aggregation was fibrinogen-dependent and platelets from patients with Glanzmann's thrombasthenia were unresponsive. The studies provide evidence that IIB post-DDAVP vWF is bound to unstimulated platelets and that the interaction between vWF and platelets in type IIB vWD is different from ristocetin-induced as well as thrombin- and epinephrine-induced binding to platelets of normal vWF.     

Platelet function and coagulation studies in patients with mitral valve prolapse

Twenty-eight consecutive patients with mitral valve prolapse (MVP), seven of whom had previous cerebrovascular disorders (CVD), were studied for platelet function and coagulation tests. While platelet function tests were found to be normal with the exception of platelet aggregation rate (PAR), there was a significant rise of factors VIII vWF:Ag (Von Willebrand) and (FPA) fibrinopeptide A. Six cases had high levels of both these factors, suggesting the existence of a particular subset of patients with MVP, with a higher risk of thromboembolic episodes, although only three out of seven patients with previous CVD had either FPA or VIII vWF:Ag levels. The broad spectrum of subjects with MVP probably explains the different results obtained when studying platelet function and coagulation factors. Therefore, larger population studies and prolonged follow-up of cases with either coagulation abnormalities similar to the ones found in the present report and/or altered platelet function tests are suggested to discover if it is possible to detect patients with a potential for thromboembolism.     

外泌体在寄生虫及媒介病毒中的研究进展

人体寄生虫主要分为医学原虫、医学蠕虫和医学节肢动物。在寄生虫与其宿主漫长的共同进化中,要求寄生虫建立一种强大的适应性和一系列复杂的分子机制来逃避、抑制宿主细胞免疫系统的攻击,同时激活宿主细胞协助调控其寄生环境,以最大限度地生存并触发和保持感染。近些年,受哺乳动物外泌体相关研究启发,研究人员发现,外泌体在以上过程中发挥着重要的作用,比如参与调节虫体的毒力、参与虫体的免疫逃逸或免疫抑制、维持寄生虫病的感染和转归。现如今,人体寄生虫领域的外泌体研究取得了一定的成果,本文针对寄生虫源外泌体以及宿主源性外泌体在寄生和感染时发挥的作用及其作用机制进行综述,同时针对外泌体与媒介病毒的研究进展进行简要概述。     

Platelet and Thrombin Activity Following Cardiac Catheterization Despite Treatment with Aspirin

Thromboembolic complications are reported to occur in up to 0.5–2% of left cardiac catheterizations and angiographies. Activation of the hemostatic system may contribute to their onset. To prevent platelet and thrombin activity during catheterization, aspirin or systemic heparin are often used in addition to heparinized flush solutions. We investigated whether aspirin alone can prevent platelet and thrombin activity induced by catheterization in ten consecutive patients (nine males, mean 50 ± 8 years) undergoing elective left cardiac catheterization after at least 5 days of oral aspirin (75–300 mg/d). Anticoagulant drugs were not given. Peripheral venous samples were drawn before, immediately after (time 0), and at 15, 60, and 180 minutes after the procedure for measurement of thrombin–antithrombin (TAT), prothrombin fragment 1.2 (F 1.2), fibrinopeptide A (FPA), and -thromboglobulin (-TG). TAT, F1.2, and FPA increased significantly at time 0 compared with both before and 180 minutes after the procedure (P < 0.04); -TG values were higher at time 0 compared with 180 minutes later (P = 0.01). TAT levels were related to those of FPA (r = 0.66; P = 0.0003), F1.2 (r = 0.35; P = 0.01), and -TG (r = 0.37; p = 0.04). Thus, routine left cardiac catheterization is associated with transient, systematically detectable, activation of coagulation and platelets, despite aspirin therapy. Newer antiplatelet agents may be more effective in preventing hemostatic activation induced by catheterization.     

Platelet aggregation in hyperapobetalipoproteinemia

Hyperapobetalipoproteinemia (HyperapoB) is a lipid disorder characterized by premature coronary disease, although the mechanisms have not been elucidated. Because abnormalities in platelet function may represent an enhanced susceptibility to coronary thrombosis, the aggregability of platelets was examined in hyperapoB subjects. Compared to controls, there were no significant differences in either platelet lipid composition or in aggregation to epinephrine, ADP, or collagen. In contrast to other dyslipidemias, platelet function does not appear to be abnormal in this well defined lipid disorder.     

上海市市售食品食源性寄生虫污染状况调查

目的 了解上海市市售食品中食源性寄生虫污染状况, 为制定寄生虫病监测策略、 保障食品安全提供依据。方法 采用分层整群随机抽样调查方法, 2005-2010年对上海市18个区 （县） 部分农贸市场和超市的淡水类水产品、 海水类水产品、 蔬果类、 肉类、 螺类和蛙类等样品, 分别采用消化法、 压片法、 剖检法和漂浮法检测寄生虫囊蚴、 幼虫和虫卵。结果 2005-2010年共检测淡水类水产品23种5 185尾, 寄生虫囊蚴感染率为1.93%。检测淡水鱼、 虾20种4 033尾, 华支睾吸虫囊蚴感染率为1.76%; 其中麦穗鱼感染率最高, 为7.83% （48/613）, 显著高于其他鱼种 （P < 0.01）。检测淡水甲壳类1 152 只, 未检出并殖吸虫囊蚴。检测海水产品23种433尾, 异尖线虫幼虫感染率为12.70%; 其中鲐鱼和带鱼异尖线虫幼虫感染率分别为50.00% （13/26） 和23.46% （42/179）, 显著高于其他海产品 （P < 0.01）。检测蔬菜37种428份, 寄生虫虫卵检出率为 0.47% （1/428）; 检测10种水果103份, 未检出寄生虫虫卵。检测螺类样品330份, 未检出广州管圆线虫幼虫。检测青蛙102 只, 曼氏迭宫绦虫裂头蚴感染率为31.37%。检测猪、 牛肉样品116份, 未检出寄生虫污染。 同期居民肠道寄生虫感染率为 0.42% （131/31 239）。 结论 上海市部分市售食品受到寄生虫污染。应加强食品卫生宣教工作, 采取有效的综合防治措施, 以确保提供安全的食品     

Intestinal parasites: Associations with intestinal and systemic inflammation

The aim of the present study was to evaluate associations between intestinal parasitic infection with intestinal and systemic inflammatory markers in school‐aged children with high rates of obesity. Plasma concentrations of C‐Reactive Protein (CRP), leptin, TNF‐α, IL‐6 and IL‐10 were measured as systemic inflammation markers and count of stool leukocytes as marker of intestinal inflammation in 291 children (6‐10 years). Intestinal parasitic infection was measured by stool examination. Logistic regression analyses were performed to determine the odds of having high inflammatory markers for each parasite or group of parasites as compared to parasite‐free children while adjusting for sex, age, mother's educational level and percentage of body fat. The prevalence of soil‐transmitted helminths and intestinal protozoa infections was 12% and 36%, respectively. Parasitic infection was not associated with CRP, IL‐6, IL‐10 or TNF‐α. Children infected with Ascaris lumbricoides (aOR: 5.91, 95% CI: 1.97‐17.70) and Entamoeba coli (aOR: 8.46, 95% CI: 2.85‐25.14) were more likely to have higher stool leucocytes than parasite‐free children. Children with multiple infections (aOR: 10.60, 95% CI: 2.85‐25.14) were more likely to have higher leptin concentrations than parasite‐free children. Intestinal parasitic infection was not associated with systemic inflammation, but was associated with intestinal inflammation. Having multiple infections were associated with higher leptin concentrations.     

Platelet Function Related to the Development and Presenting Symptoms in Coronary Artery Disease

Among 2014 apparently healthy men aged 40–59 years platelet function was studied with Hellem's retention method in 488 men. In 55 of these 488 men coronary heart disease (CHD) was strongly suspected and coronary angiography confirmed the diagnosis in 34 of 51 angiographied men. Platelet responsiveness was significantly lower among those who had angina pectoris than among their CHD-suspect counterparts without angina, regardless of coronary angiographic findings. Since angiopositive men without angina and 408 ‘normals’ had similar retention values, it seems as if presenting symptoms, but not the development of CHD are linked to platelet function. During a near maximal bicycle exercise test significantly higher peak exercise blood pressure was found among men with very low retention values than among men with rention values in the middle and upper range. This could not be explained by differences in maximal heart rate or work performance. This indicates that blood pressure regulation during exercise may in part be linked to platelet function related mechanisms.     

Platelets in Myeloproliferative Disorders. III: Glycoprotein Profile in Relation to Platelet Function and Platelet Density

Membrane glycoproteins (GP) are implicated in platelet functions. In myeloproliferative diseases (MD), some of these functions are known to be perturbed. 16 patients with various MD were investigated for platelet functions (retention to glass beads, epinephrine- and ristocetin-induced aggregation), platelet density distribution and PAS-staining glycoprotein profile on SDS-polyacrylamide-gel-electrophoresis. An abnormal GP pattern (moderate reduction of GP (Ib + Is) and GP IIb with corresponding increase in GP IIIb) was demonstrated but no relation to platelet dysfunction or density distribution was observed. No differences between the various types of MD were noticed although the group of poly-cythaemia vera was the less perturbed for platelet function, platelet density and also GP profile.     

Prevalence of intestinal parasites in rural Southern Indians

objective   To determine the prevalence of intestinal protozoal and helminthic infection in a rural population. method   Seventy-eight members of 15 families from a village were studied. Stool samples from all subjects were examined on alternate days for one month. results   The overall prevalence rate of various parasitic infections was 97.4%, with only 2 of 78 subjects not excreting parasites in any of their 15 samples. Eighteen (23.1%) persons had only one type of parasite, while 58 (74.3%) excreted multiple parasites. Giardia and Cryptosporidium were the commonest protozoan infections, affecting 42/78 (53.8%) and 31/78 (39.7%), respectively. Hookworm infestations were the commonest helminthic infections, seen in 48/78 (61.5%). Based on excretion patterns, the asymptomatic individuals could be divided into 2 groups of infrequent and frequent excretors, indicating that the host response may determine the level of parasite replication in the gut.     

Platelet glycosomes

Most of the structural constituents of human platelets have been well characterized in ultrastructural studies over the past five decades. However, some structures occur rarely and have not been reported previously. The present article describes an organelle bounded by a unit membrane and filled with particles of glycogen. For that reason we have called this organelle the 'glycosome'. Similarities and differences between glycosomes, alpha-granules and tubular inclusions are discussed.     

Splenic Platelet Kinetics and Platelet Production after Major Reconstructive Vascular Surgery

ABSTRACT By using ¹¹¹In-labelled platelets and dynamic gamma camera scintigraphy, platelet production rate and intrasplenic platelet kinetics were determined in 13 patients at 1 and 4 months after aortic reconstructive vascular surgery with implantation of dacron prostheses. A significant decrease in platelet production rate and venous platelet count was recorded over time after surgery. Irrespective of whether the exchangeable splenic platelet pool was estimated from initial recovery of platelet-bound radioactivity or from compartmental analysis, the size of this pool was significantly lower at the first study; a change in intrasplenic platelet transit time accounted for the observed difference. Platelet mean life-span increased over time after surgery but the difference between the duplicate studies was not statistically significant. It can be concluded that there is a reduction of platelet production rate and venous platelet count over time after major reconstructive vascular surgery. The early postoperative elevation in the platelet count is mainly the result of an increased platelet production and to a lesser degree due to redistribution of platelets between the splenic platelet pool and general circulation.     

Platelet activation in obesity and metabolic syndrome

Obesity is associated with increased cardiovascular disease. Metabolic syndrome (MS) identifies substantial additional cardiovascular risk beyond the individual risk factors, and is a powerful predictor of cardiovascular events even regardless of body mass index, thus suggesting a common downstream pathway conferring increased cardiovascular risk. Platelet hyper-reactivity/activation plays a central role to accelerate atherothrombosis and is the result of the interaction among the features clustering in obesity and MS: insulin resistance, inflammation, oxidative stress, endothelial dysfunction. Interestingly, the same pathogenic events largely account for the less-than-expected response to antiplatelet agents, namely low-dose aspirin. The proposed explanations for this phenomenon, besides underdosing of drug and/or reduced bioavailability, subsequent to excess of adipose tissue, include enhanced platelet turnover, leading to unacetylated COX-1 and COX-2 in newly formed platelets as a source of aspirin-escaping thromboxane formation; extraplatelet sources of thromboxane, driven by inflammatory triggers; and enhanced lipid peroxidation, activating platelets with a mechanism bypassing COX-1 acetylation or limiting COX-isozyme acetylation by aspirin. This review will address the complex interactions between platelets and the pathogenic events occurring in obesity and MS, trying to translate this body of mechanistic information into a clinically relevant read-out, in order to establish novel strategies in the prevention/treatment of atherothrombosis.     

Platelet mass has prognostic value in patients with myelodysplastic syndromes

Platelet mass (mean platelet volume x platelet count) can be derived from data obtained from the routine full blood count and separates patients with myelodysplastic syndromes (MDS) at diagnosis into three distinct prognostic groups: low platelet mass group - median survival 5 months and 5-year survival 0%; intermediate platelet mass group - median survival 30 months and 5-year survival 34%; high platelet mass group median survival - not reached at 82 months follow-up with a 5-year survival of 82%. These data provide a simple rapid prognostic index at the time of diagnosis in MDS.     

Platelet activation in normo- and hyperlipoproteinemias

Summary In the last few years it became obvious that platelets are involved in the development of atherosclerotic diseases. This involvement of platelets has been taken into account in the response to injury hypothesis of atherosclerosis. The hypothesis is based on the assumption that atherosclerotic lesions result from endothelial injury, followed by the interaction of, vessel wall constituents with lipoproteins, macrophages, and platelets.In the first part of this review, general aspects of platelet activation are summarized and the pathways of platelet aggregation as well as their involvement in blood coagulation are discussed.The second part of this paper describes the influence of cholesterol, lipoproteins, and apolipoproteins upon the activation and metabolic behavior of, platelets. Physiological and pathophysiological processes particularly occurring in different types of hyperlipoproteinemias and atherosclerotic disorders are discussed in this context.