Pericardial Cells Research Articles

Quercetin and Cisplatin combined treatment altered cell cycle and mitogen activated protein kinase expressions in malignant mesotelioma cells.

BackgroundMalignant mesothelioma is a locally aggressive and highly lethal neoplasm of pleural, peritoneal and pericardial mesothelial cells without successful therapy. Previously, we reported that Quercetin in combination with Cisplatin inhibits cell proliferation and activates caspase-9 and -3 enzymes in different malignant mesothelioma cell lines. Moreover, Quercetin + Cisplatin lead to accumulation of both SPC111 and SPC212 cell lines in S phase.MethodsIn present work, 84 genes involved in cell growth and proliferation have analysed by using RT2-PCR array system and protein profile of mitogen activated protein kinase (MAPK) family proteins investigated by western blots.ResultsOur results showed that Quercetin and Quercetin + Cisplatin modulated gene expression of cyclins, cyclin dependent kinases and cyclin dependent kinases inhibitors. In addition genes involved in JNK, p38 and MAPK/ERK pathways were up regulated. Moreover, while p38 and JNK phosphorylations were increased, ERK phosphorylations were decreased after using Quercetin + Cisplatin.ConclusionThis research has clarified our previous results and detailed mechanism of anti-carcinogenic potential of Quercetin alone and incombination with Cisplatin on malignant mesothelioma cells.

Gia/Mthl5 is an aorta specific GPCR required for Drosophila heart tube morphology and normal pericardial cell positioning

G-protein signaling is known to be required for cell-cell contacts during the development of the Drosophila dorsal vessel. However, the identity of the G protein-coupled receptor (GPCR) that regulates this signaling pathway activity is unknown. Here we describe the identification of a novel cardiac specific GPCR, called Gia, for “GPCR in aorta”. Gia is the only heart-specific GPCR identified in Drosophila to date and it is specifically expressed in cardioblasts that fuse at the dorsal midline to become the aorta. Gia is the only Drosophila gene so far identified for which expression is entirely restricted to cells of the aorta. Deletion of Gia led to a broken-hearted phenotype, characterized by pericardial cells dissociated from cardioblasts and abnormal distribution of cell junction proteins. Both phenotypes were similar to those observed in mutants of the heterotrimeric cardiac G proteins. Lack of Gia also led to defects in the alignment and fusion of cardioblasts in the aorta. Gia forms a protein complex with G-αo47A, the alpha subunit of the heterotrimeric cardiac G proteins and interacts genetically with G-αo47A during cardiac morphogenesis. Our study identified Gia as an essential aorta-specific GPCR that functions upstream of cardiac heterotrimeric G proteins and is required for morphological integrity of the aorta during heart tube formation. These studies lead to a redefinition of the bro phenotype, to encompass morphological integrity of the heart tube as well as cardioblast-pericardial cell spatial interactions.

Hepato-Nephrocitic System: A Novel Model of Biomarkers for Analysis of the Ecology of Stress in Environmental Biomonitoring.

Bombus presents a serious global decline of populations and even loss of species. This phenomenon is complex and multifactorial: environmental degradation due to increasing cultivation and grazing areas, indiscriminate use of agrochemicals, and a plethora of xenobiotics daily discharged in the environment. We proposed that bees have an integrated cell system, which ensures protection against chemical stressors up to a certain limit. Therefore, this hypothesis was tested, exposing workers of Bombus morio to cadmium, a harmful trace metal nowadays widespread in our society. The workers were kept in BOD (26°C, RH 70%, in the dark), fed ad libitum, and divided into a control group (n = 20) and an experimental group (n = 20). For the first group, we offered 2 mL of distilled water; for the experimental groups, 2mL of cadmium at 1 ppb. In relation to the control group, exposed bees showed that their fat body and hemocytes responded in synchronization with pericardial cells in a topographical and temporal cascade of events, where the fat body is the first barrier against xenobiotics, followed by pericardial cells. The immune cells participate throughout the process. To this system, we proposed the name of hepato-nephrocitic system (HNS), which may explain many phenomena that remain unclear in similar research with Apis mellifera and other species of bees, as shown in this paper. The bee’s HNS is a system of highly responsive cells to toxicants, considered a novel parameter for the study of the ecology of stress applied in environmental management.

Ferritin Is Required in Multiple Tissues during Drosophila melanogaster Development.

In Drosophila melanogaster, iron is stored in the cellular endomembrane system inside a protein cage formed by 24 ferritin subunits of two types (Fer1HCH and Fer2LCH) in a 1:1 stoichiometry. In larvae, ferritin accumulates in the midgut, hemolymph, garland, pericardial cells and in the nervous system. Here we present analyses of embryonic phenotypes for mutations in Fer1HCH, Fer2LCH and in both genes simultaneously. Mutations in either gene or deletion of both genes results in a similar set of cuticular embryonic phenotypes, ranging from non-deposition of cuticle to defects associated with germ band retraction, dorsal closure and head involution. A fraction of ferritin mutants have embryonic nervous systems with ventral nerve cord disruptions, misguided axonal projections and brain malformations. Ferritin mutants die with ectopic apoptotic events. Furthermore, we show that ferritin maternal contribution, which varies reflecting the mother’s iron stores, is used in early development. We also evaluated phenotypes arising from the blockage of COPII transport from the endoplasmic reticulum to the Golgi apparatus, feeding the secretory pathway, plus analysis of ectopically expressed and fluorescently marked Fer1HCH and Fer2LCH. Overall, our results are consistent with insect ferritin combining three functions: iron storage, intercellular iron transport, and protection from iron-induced oxidative stress. These functions are required in multiple tissues during Drosophila embryonic development.

Distinct functions of the laminin β LN domain and collagen IV during cardiac extracellular matrix formation and stabilization of alary muscle attachments revealed by EMS mutagenesis in Drosophila.

BackgroundThe Drosophila heart (dorsal vessel) is a relatively simple tubular organ that serves as a model for several aspects of cardiogenesis. Cardiac morphogenesis, proper heart function and stability require structural components whose identity and ways of assembly are only partially understood. Structural components are also needed to connect the myocardial tube with neighboring cells such as pericardial cells and specialized muscle fibers, the so-called alary muscles.ResultsUsing an EMS mutagenesis screen for cardiac and muscular abnormalities in Drosophila embryos we obtained multiple mutants for two genetically interacting complementation groups that showed similar alary muscle and pericardial cell detachment phenotypes. The molecular lesions underlying these defects were identified as domain-specific point mutations in LamininB1 and Cg25C, encoding the extracellular matrix (ECM) components laminin β and collagen IV α1, respectively. Of particular interest within the LamininB1 group are certain hypomorphic mutants that feature prominent defects in cardiac morphogenesis and cardiac ECM layer formation, but in contrast to amorphic mutants, only mild defects in other tissues. All of these alleles carry clustered missense mutations in the laminin LN domain. The identified Cg25C mutants display weaker and largely temperature-sensitive phenotypes that result from glycine substitutions in different Gly-X-Y repeats of the triple helix-forming domain. While initial basement membrane assembly is not abolished in Cg25C mutants, incorporation of perlecan is impaired and intracellular accumulation of perlecan as well as the collagen IV α2 chain is detected during late embryogenesis.ConclusionsAssembly of the cardiac ECM depends primarily on laminin, whereas collagen IV is needed for stabilization. Our data underscore the importance of a correctly assembled ECM particularly for the development of cardiac tissues and their lateral connections. The mutational analysis suggests that the β6/β3/β8 interface of the laminin β LN domain is highly critical for formation of contiguous cardiac ECM layers. Certain mutations in the collagen IV triple helix-forming domain may exert a semi-dominant effect leading to an overall weakening of ECM structures as well as intracellular accumulation of collagen and other molecules, thus paralleling observations made in other organisms and in connection with collagen-related diseases.

ROS Regulate Cardiac Function via a Distinct Paracrine Mechanism

SUMMARYReactive oxygen species (ROS) can act cell autonomously and in a paracrine manner by diffusing into nearby cells. Here, we reveal a ROS-mediated paracrine signaling mechanism that does not require entry of ROS into target cells. We found that under physiological conditions, nonmyocytic pericardial cells (PCs) of the Drosophila heart contain elevated levels of ROS compared to the neighboring cardiomyocytes (CMs). We show that ROS in PCs act in a paracrine manner to regulate normal cardiac function, not by diffusing into the CMs to exert their function, but by eliciting a downstream D-MKK3-D-p38 MAPK signaling cascade in PCs that acts on the CMs to regulate their function. We find that ROS-D-p38 signaling in PCs during development is also important for establishing normal adult cardiac function. Our results provide evidence for a previously unrecognized role of ROS in mediating PC/CM interactions that significantly modulates heart function.

Machine learning classification of cell-specific cardiac enhancers uncovers developmental subnetworks regulating progenitor cell division and cell fate specification

The Drosophila heart is composed of two distinct cell types, the contractile cardial cells (CCs) and the surrounding non-muscle pericardial cells (PCs), development of which is regulated by a network of conserved signaling molecules and transcription factors (TFs). Here, we used machine learning with array-based chromatin immunoprecipitation (ChIP) data and TF sequence motifs to computationally classify cell type-specific cardiac enhancers. Extensive testing of predicted enhancers at single-cell resolution revealed the added value of ChIP data for modeling cell type-specific activities. Furthermore, clustering the top-scoring classifier sequence features identified novel cardiac and cell type-specific regulatory motifs. For example, we found that the Myb motif learned by the classifier is crucial for CC activity, and the Myb TF acts in concert with two forkhead domain TFs and Polo kinase to regulate cardiac progenitor cell divisions. In addition, differential motif enrichment and cis-trans genetic studies revealed that the Notch signaling pathway TF Suppressor of Hairless [Su(H)] discriminates PC from CC enhancer activities. Collectively, these studies elucidate molecular pathways used in the regulatory decisions for proliferation and differentiation of cardiac progenitor cells, implicate Su(H) in regulating cell fate decisions of these progenitors, and document the utility of enhancer modeling in uncovering developmental regulatory subnetworks.

Isolation, culture and identification of primary human pericardial interstitial cells

Objective To establish a method for isolation,culture and identification of primary human pericardial interstitial cells( PICs). Methods Human pericardial tissues were cut into 1 mm × 1 mm × 1 mm sized pieces,digested with type Ⅱ collagenase,hyaluronic acid enzyme and trypsin to isolate the interstitial cells. The cells were cultured and cell morphology was observed. The cell doubling time, flow cytometry and immunohistochemical staining were applied for cell identification. Results Adherent cells were observed 24 h after culturing. The cells reached 80% confluences and could be subcultured after about 10 days. The cells isolated and cultured were fibroblast-like or spindle-like,with obvious nuclei,clear nucleolus,and a greater proportion of nucleus and cytoplasm. Flow cytometry results showed no cell surface markers CD34 and CD45. Immunocytochemistry showed negative CK staining,and positive vimentin and α-SMA staining. Cells isolated from 8 of the 10 pericardial tissues were successfully cultured. Conclusion The present method can effectively isolate and culture primary human PICs,which lays a foundation for further in vitro study of constrictive pericarditis.

Probable role of dopamine in the regulation of ventral nephrocyte functioning in Drosophila melanogaster adults

AbstractFiltration of haemolymph in insects to remove waste products is performed by nephrocytes, which comprise accessory cells of the circulatory system that are not connected to Malpighian tubules. There are two types of nephrocytes in Drosophila: ventral cells, situated around the junction between the cardia and the oesophagus, and pericardial cells, situated around the heart. In the present study, the expression of dopamine D1 (DopR) and D2‐like (DD2R) receptors in the ventral nephrocytes of Drosophila melanogaster Meigen (Diptera: Drosophilidae) is investigated. Immunohistochemical staining with polyclonal antibodies against DopR and DD2R demonstrates the presence of these receptors in adult nephrocytes. The functioning of D. melanogaster nephrocytes is investigated by evaluation of mortality rates in flies treated with silver nitrate (AgNO3) compared with untreated controls. To determine whether a change in the level of dopamine receptors has an effect on the functioning of nephrocytes, the antisense suppressor of DD2R gene together with a nephrocyte‐specific driver is used in the UAS‐GAL4 system. The suppression of DD2R in nephrocytes results in a significant decrease of mortality under toxic conditions. Taken together, the data obtained in the present study indicate that dopamine takes part in the control of ventral nephrocyte functioning in D. melanogaster.

The ultrastructure of the Aedes aegypti heart

Comparative structural analyses of the heart and associated tissues in 4th instar larvae (L4), pupae and adults of Aedes aegypti were undertaken using a combination of microscopy techniques. The Ae. aegypti heart consists of cardiomyocytes arranged in a helical fashion, and it is physically associated with intersegmental groups of pericardial cells (PCs) and the alary muscles (AMs). Ramifications commonly present in AMs are more developed in adults than in the immature stages. Pericardial cells absorb and store extracellular components as shown by the uptake of carmine dye fed in larval diet. We also observed that carmine stained inclusions corresponding to electron-dense structures resembling lysosomes that were more abundant and prominent in pupae, suggestive of increase of waste accumulation during pupation. The results presented here expand on previously known aspects of the mosquito heart and describe for the first time comparative aspects of the morphology of the heart in different developmental stages.

Silencing of Maternal Heme-binding Protein Causes Embryonic Mitochondrial Dysfunction and Impairs Embryogenesis in the Blood Sucking Insect Rhodnius prolixus

The heme molecule is the prosthetic group of many hemeproteins involved in essential physiological processes, such as electron transfer, transport of gases, signal transduction, and gene expression modulation. However, heme is a pro-oxidant molecule capable of propagating reactions leading to the generation of reactive oxygen species. The blood-feeding insect Rhodnius prolixus releases enormous amounts of heme during host blood digestion in the midgut lumen when it is exposed to a physiological oxidative challenge. Additionally, this organism produces a hemolymphatic heme-binding protein (RHBP) that transports heme to pericardial cells for detoxification and to growing oocytes for yolk granules and as a source of heme for embryo development. Here, we show that silencing of RHBP expression in female fat bodies reduced total RHBP circulating in the hemolymph, promoting oxidative damage to hemolymphatic proteins. Moreover, RHBP knockdown did not cause reduction in oviposition but led to the production of heme-depleted eggs (white eggs). A lack of RHBP did not alter oocyte fecundation. However, produced white eggs were nonviable. Embryo development cellularization and vitellin yolk protein degradation, processes that normally occur in early stages of embryogenesis, were compromised in white eggs. Total cytochrome c content, cytochrome c oxidase activity, citrate synthase activity, and oxygen consumption, parameters that indicate mitochondrial function, were significantly reduced in white eggs compared with normal dark red eggs. Our results showed that reduction of heme transport from females to growing oocytes by RHBP leads to embryonic mitochondrial dysfunction and impaired embryogenesis.

The Iroquois Complex Is Required in the Dorsal Mesoderm to Ensure Normal Heart Development in Drosophila

Drosophila heart development is an invaluable system to study the orchestrated action of numerous factors that govern cardiogenesis. Cardiac progenitors arise within specific dorsal mesodermal regions that are under the influence of temporally coordinated actions of multiple signaling pathways. The Drosophila Iroquois complex (Iro-C) consists of the three homeobox transcription factors araucan (ara), caupolican (caup) and mirror (mirr). The Iro-C has been shown to be involved in tissue patterning leading to the differentiation of specific structures, such as the lateral notum and dorsal head structures and in establishing the dorsal-ventral border of the eye. A function for Iro-C in cardiogenesis has not been investigated yet. Our data demonstrate that loss of the whole Iro complex, as well as loss of either ara/caup or mirr only, affect heart development in Drosophila . Furthermore, the data indicate that the GATA factor Pannier requires the presence of Iro-C to function in cardiogenesis. Furthermore, a detailed expression pattern analysis of the members of the Iro-C revealed the presence of a possibly novel subpopulation of Even-skipped expressing pericardial cells and seven pairs of heart-associated cells that have not been described before. Taken together, this work introduces Iro-C as a new set of transcription factors that are required for normal development of the heart. As the members of the Iro-C may function, at least partly, as competence factors in the dorsal mesoderm, our results are fundamental for future studies aiming to decipher the regulatory interactions between factors that determine different cell fates in the dorsal mesoderm.

The Conserved ADAMTS-like Protein Lonely heart Mediates Matrix Formation and Cardiac Tissue Integrity

Here we report on the identification and functional characterization of the ADAMTS-like homolog lonely heart (loh) in Drosophila melanogaster. Loh displays all hallmarks of ADAMTSL proteins including several thrombospondin type 1 repeats (TSR1), and acts in concert with the collagen Pericardin (Prc). Loss of either loh or prc causes progressive cardiac damage peaking in the abolishment of heart function. We show that both proteins are integral components of the cardiac ECM mediating cellular adhesion between the cardiac tube and the pericardial cells. Loss of ECM integrity leads to an altered myo-fibrillar organization in cardiac cells massively influencing heart beat pattern. We show evidence that Loh acts as a secreted receptor for Prc and works as a crucial determinant to allow the formation of a cell and tissue specific ECM, while it does not influence the accumulation of other matrix proteins like Nidogen or Perlecan. Our findings demonstrate that the function of ADAMTS-like proteins is conserved throughout evolution and reveal a previously unknown interaction of these proteins with collagens.

The Drosophila Nephrocyte

Drosophila nephrocytes have been an object of study for more than a century. They were named by Bruntz, based on observations of cells around the heart, the central nervous system, and in the sternal area in scorpions.[1][1] Kowalevsky suggested that they function as a storage kidney, because they

Infection-Induced Interaction between the Mosquito Circulatory and Immune Systems

Insects counter infection with innate immune responses that rely on cells called hemocytes. Hemocytes exist in association with the insect's open circulatory system and this mode of existence has likely influenced the organization and control of anti-pathogen immune responses. Previous studies reported that pathogens in the mosquito body cavity (hemocoel) accumulate on the surface of the heart. Using novel cell staining, microdissection and intravital imaging techniques, we investigated the mechanism of pathogen accumulation in the pericardium of the malaria mosquito, Anopheles gambiae, and discovered a novel insect immune tissue, herein named periostial hemocytes, that sequesters pathogens as they flow with the hemolymph. Specifically, we show that there are two types of endocytic cells that flank the heart: periostial hemocytes and pericardial cells. Resident periostial hemocytes engage in the rapid phagocytosis of pathogens, and during the course of a bacterial or Plasmodium infection, circulating hemocytes migrate to the periostial regions where they bind the cardiac musculature and each other, and continue the phagocytosis of invaders. Periostial hemocyte aggregation occurs in a time- and infection dose-dependent manner, and once this immune process is triggered, the number of periostial hemocytes remains elevated for the lifetime of the mosquito. Finally, the soluble immune elicitors peptidoglycan and β-1,3-glucan also induce periostial hemocyte aggregation, indicating that this is a generalized and basal immune response that is induced by diverse immune stimuli. These data describe a novel insect cellular immune response that fundamentally relies on the physiological interaction between the insect circulatory and immune systems.

Antimicrobial properties of Anopheles albimanus pericardial cells

Insect pericardial cells (PCs) are strategically located along the dorsal vessel where they encounter a high hemolymph flow enabling them to undertake their osmoregulatory, detoxifying, and scavenging functions. In this location, PCs also encounter foreign molecules and microorganisms. The response of PCs of the mosquito Anopheles albimanus, one of the most important Plasmodium vivax vectors in Mexico and Latin America, to Saccharomyces cerevisiae was analyzed by using biochemical, cellular, ultrastructural, and bioinformatics approaches. Immune gene transcripts were identified in the PC transcriptome of A. albimanus. PCs responded to the presence of yeast and zymosan with increased lysosomal and phosphatase activities and produced lytic activity against bacteria. Our results indicate that mosquito PCs play a key role in the neutralization and elimination of pathogens.

Aortic valve replacement with autologous pericardium: long-term follow-up of 15 patients and in vivo histopathological changes of autologous pericardium

The study aimed to assess the long-term follow-up of patients with an autologous pericardial aortic valve (APAV) replacement and to analyse in vivo histopathological changes in implanted APAVs. From 1996 to 1997, 15 patients (mean age, 34 years) underwent aortic valve replacement with the glutaraldehyde-treated autologous pericardium. All patients were followed up after discharge. The excised APAVs were processed for haematoxylin-eosin, Victoria blue-van Gieson and immunohistochemical staining. The mean clinical follow-up was 11.43 ± 4.50 years. APAV-related in-hospital and late mortalities were both 0%. Five (33%) patients required reoperation because of a prolapse of the right coronary cusp (n = 1), infective endocarditis (n = 1) or fibrocalcific degeneration (n = 3). Freedom from endocarditis, fibrocalcific degeneration and reoperation at the end of follow-up was 93, 80 and 67%, respectively. The remaining 10 patients were alive and well with a mean New York Heart Association class of 1.10 ± 0.32 and normally functioning aortic valves (peak pressure gradient: 7.70 ± 3.41 mmHg; mean pressure gradient: 1.79 ± 0.64 mmHg). Histopathology revealed that (i) a thin factor VIII-positive layer (endothelialization) was found on all non-endocarditis APAVs; (ii) pericardial cells in all APAVs were positive for α-smooth muscle actin (myofibroblast phenotype) and some cells in the fibrocalcific APAVs were positive for alkaline phosphatase (osteoblast phenotype) and (iii) an elastic band was found in 3 cases (in vivo >9 years). APAV replacement is a procedure with a low mortality. APAVs adapt to new environmental demands by producing an elastic band and by endothelialization, whereas myofibroblast/osteoblast transdifferentiation seems to be responsible for the fibrocalcification of APAVs.

A Resource for Manipulating Gene Expression and Analyzing cis-Regulatory Modules in the Drosophila CNS

Here, we describe the embryonic central nervous system expression of 5,000 GAL4 lines made using molecularly defined cis-regulatory DNA inserted into a single attP genomic location. We document and annotate the patterns in early embryos when neurogenesis is at its peak, and in older embryos where there is maximal neuronal diversity and the first neural circuits are established. We note expression in other tissues, such as the lateral body wall (muscle, sensory neurons, and trachea) and viscera. Companion papers report on the adult brain and larval imaginal discs, and the integrated data setsare available online (http://www.janelia.org/gal4-gen1). This collection of embryonically expressed GAL4 lines will be valuable for determining neuronal morphology and function. The 1,862 lines expressed in small subsets of neurons (<20/segment) will be especially valuable for characterizinginterneuronal diversity and function, because although interneurons comprise the majority of all central nervous system neurons, their gene expression profile and function remain virtually unexplored.

Characteristics of pericardial interstitial cells and their implications in pericardial fibrocalcification

Pericardial fibrocalcification (PF) is a prominent feature of human pericardial pathology, including constrictive pericarditis and, to a lesser extent, degenerated autologous pericardial substitutes. However, the role of pericardial interstitial cells (PICs) in the pathogenesis of PF has yet to be established. Using a combination of histology and immunohistochemistry, we showed that the critical cellular event in PF in situ was the transdifferentiation of PICs into myofibroblasts/osteoblasts and that the percentage of myofibroblasts/osteoblasts correlated positively with the severity of PF. In vitro studies demonstrated that PICs, similar to mesenchymal stem cells, had the potential to differentiate along adipogenic, osteogenic, chondrogenic or myogenic lineages. However, PICs exhibited a more limited self-renewal capacity and a lower expression of Oct4 (POU5F1) and Kruppel-like transcription factor Klf4, underwent earlier senescence and spontaneously transdifferentiated into myofibroblasts/osteoblasts. Quantitative-real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) confirmed that the mRNA levels of α-smooth muscle actin (α-SMA), alkaline phosphatase (ALP), core-binding factor α1/runt-related transcription factor2 (Cbfa1/Runx2), transforming growth factor (TGF)-β1 and bone morphogenetic protein (BMP)-2 were upregulated as the passage number increased. The mRNA level of platelet-derived growth factor (PDGF)-AA was also significantly upregulated with higher levels at passage 3. Ectopic expression of Oct4 and Klf4 enhanced the colony formation of PICs and selectively impaired induction of genes involved in transdifferentiation into myofibroblasts/osteoblasts (α-SMA, ALP, Cbfa1/Runx2, PDGF-AA and BMP-2). These data, while offering new insights into the biology of PICs, reinforce the central role of these cells in cell-mediated PF and may assist in future strategies to treat fibrocalcific pericardial diseases.

Diagnostic value of biochemical biomarkers in malignant and non-malignant pericardial effusion

The aim of this study was to examine the biochemical composition of pericardial effusions of different etiology and to evaluate the diagnostic utility of biochemical parameters and tumor markers to discriminate malignant from benign effusion. Pericardial and serum levels of biochemical parameters and tumor markers were compared in 105 patients who underwent pericardiocentesis and pericardioscopy with targeted epicardial biopsy. Etiologic diagnosis was based on pericardial fluid and epicardial biopsy analysis by cytology, histology, immunohistochemistry, microbiology and polymerase chain reaction. The total of 105 patients comprised 29 patients with malignant and 76 patients with non-malignant pericardial effusions (40 autoreactive, 28 viral, 5 postcardiotomy syndromes and 3 associated with systemic diseases). Malignant pericardial effusions had significantly higher pericardial fluid levels of the tumor markers CEA, CA 19-9, CA 72-4, SCC and NSE (p<0.001, p=0.002, p<0.001, p=0.004 and p<0.001, respectively) as well as higher pericardial fluid hemoglobin (p<0.001), pericardial fluid white blood cells (p=0.003), pericardial fluid LDH (p<0.001) and ratio of pericardial to serum LDH levels compared to benign effusions. None of the biochemical or cell-count parameters tested proved to be accurate enough for distinguishing malignant from benign effusions. However, measurement of pericardial CA 72-4 levels offered a high diagnostic accuracy for malignancy, particularly in bloody pericardial effusions. None of the biochemical parameters tested was useful for the discrimination of malignant from benign effusions. However, measurement of pericardial CA 72-4 levels in bloody pericardial effusions yielded a high diagnostic accuracy and thus offers the potential as a diagnostic tool to distinguish between malignant and benign effusions.