Value of tyrosinase RNA detection by an RT-PCR method in melanoma prognosis.
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Antineoplastic Agents↗
Biomedical subjects
K Konstantopoulos
Publications and source records attributed to K Konstantopoulos.
Familial Mediterranean fever associated pyrin mutations in Greece.
OBJECTIVE: To search for pyrin mutations associated with familial Mediterranean fever (FMF) in Greece. PATIENTS AND METHODS: 62 patients fulfilling the Tel Hashomer diagnostic criteria for definite (33) or probable (29) FMF diagnosis were studied. Eight point mutations of pyrin gene were tested by standard methods. Of the 62 patients tested, 48 were Greek, four were Jewish, seven were Armenian, and three were Arab. RESULTS: 42 patients were found to be homozygotes for pyrin mutations; 11 patients were found to carry only one of the tested mutations; in nine patients no mutations were detected. CONCLUSION: Molecular detection of pyrin gene mutations seems useful in confirming suspected cases, and in detecting asymptomatic cases, of Mediterranean fever in Greece. It may also be used as a screening tool within affected families.
Arabs↗
Transient monoclonal hypergammaglobulinemia during the course of a rickettsia infection.
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Aged↗
Pityriasis rosea associated with imatinib (STI571, Gleevec).
A tyrosine kinase inhibitor (STI571, Gleevec) has recently been applied in the treatment of chronic myeloid leukemia. We present the first reported case of pityriasis rosea occurring as a reaction to Gleevec in a woman with blast crisis of this disorder. It is suggested that although coincidental, this exanthem may be due to this agent.
Adult↗
Hydrodynamic shear regulates the kinetics and receptor specificity of polymorphonuclear leukocyte-colon carcinoma cell adhesive interactions.
The ability of tumor cells to metastasize hematogenously is regulated by their interactions with polymorphonuclear leukocytes (PMNs). However, the mechanisms mediating PMN binding to tumor cells under physiological shear forces remain largely unknown. This study was designed to characterize the molecular interactions between PMNs and tumor cells as a function of the dynamic shear environment, using two human colon adenocarcinoma cell lines (LS174T and HCT-8) as models. PMN and colon carcinoma cell suspensions, labeled with distinct fluorophores, were sheared in a cone-and-plate rheometer in the presence of the PMN activator fMLP. The size distribution and cellular composition of formed aggregates were determined by flow cytometry. PMN binding to LS174T cells was maximal at 100 s(-1) and decreased with increasing shear. At low shear (100 s(-1)) PMN CD11b alone mediates PMN-LS174T heteroaggregation. However, L-selectin, CD11a, and CD11b are all required for PMN binding to sialyl Lewis(x)-bearing LS174T cells at high shear (800 s(-1)). In contrast, sialyl Lewis(x)-low HCT-8 cells fail to aggregate with PMNs at high shear conditions, despite extensive adhesive interactions at low shear. Taken together, our data suggest that PMN L-selectin initiates LS174T cell tethering at high shear by binding to sialylated moieties on the carcinoma cell surface, whereas the subsequent involvement of CD11a and CD11b converts these transient tethers into stable adhesion. This study demonstrates that the shear environment of the vasculature modulates the dynamics and molecular constituents mediating PMN-tumor cell adhesion.
Adenocarcinoma↗
Waldenström's macroglobulinemia: clinical course and prognostic factors in 60 patients. Experience from a single hematology unit.
Waldenström's macroglobulinemia (WM) is a lymphoplasmacytic lymphoma characterized by the presence in patients' serum of an IgM monoclonal component. We report on our experience with 60 WM patients, focusing on their clinical findings, response to treatment, and the possible identification of prognostic factors. Of these patients, 70% presented with fatigue, and lymphadenopathy was observed in 22%, splenomegaly in 18%, hepatomegaly in 13%, and extranodal site of involvement in 6%. Bleeding tendency was seen in 17%, infections in 17%, hyperviscosity syndrome in 12%, and cardiac failure in 25% of the patients. The median of IgM levels was 30 g/l with hypoalbuminemia in 20% of cases, hypogammaglobulinemia in 27%, polyclonal hypergammaglobulinemia in 15%, kappa light-chain restriction in 78%, and Bence-Jones proteinuria in 54%. Anemia was frequent (85%), followed by leukocytosis (18%), lymphocytosis (12%), leukopenia (10%), and thrombocytopenia (10%). Cryoglobulinemia and autoimmune hemolytic anemia were encountered in 5%. In all cases but two, bone marrow was involved. Of 50 patients initially treated with intermittent oral chlorambucil, 46 (92%) responded. Median overall survival was 108 months. Factors associated with adverse prognosis were age > or =65 years (p=0.06), presence of lymphadenopathy (p=0.06), bone marrow infiltration > or =50% (p=0.007), international prognostic index (IPI) > or =3 (p=0.0001), and Morel's scoring system (p=0.04). Concluding, we found in this series of WM patients that chlorambucil is an effective treatment and that the parameters of age, lymphadenopathy, percentage of bone marrow infiltration, IPI, and Morel's scoring system carry prognostic significance.
Adult↗
Glycolipids support E-selectin-specific strong cell tethering under flow.
This study provides functional evidence that glycosphingolipids constitute ligands for E-selectin but not P-selectin. Chinese hamster ovary (CHO) cells expressing E-selectin (CHO-E) or P-selectin (CHO-P) were perfused over alpha2,3-sialyl Lewis X (alpha2,3-sLe(x)) presented as the hexaosylceramide glycosphingolipid adsorbed in a monolayer containing phosphatidylcholine and cholesterol. CHO-E cells tethered extensively and formed slow, stable rolling interactions with alpha2,3-sLe(x) glycosphingolipid but not with the comparable alpha2,6-sLe(x) glycosphingolipid. Tethering/rolling varied with wall shear stress, selectin density, and ligand density. In contrast, alpha2,3-sLe(x) glycosphingolipid supported only limited, fast CHO-P cell rolling. As calculated from a stochastic model of cell rolling, the step size between successive bond releases from the alpha2,3-sLe(x) glycosphingolipid was smaller for CHO-E than CHO-P cells, whereas the opposite effect was observed for the waiting time between these events. Detachment assays revealed stronger adhesive interactions of CHO-E than CHO-P cells with alpha2,3-sLe(x) glycosphingolipid. These findings indicate that glycosphingolipids expressing an appropriate oligosaccharide mediate cell tethering/rolling via E-selectin but not P-selectin.
Animals↗
Detection of CD55- and/or CD59-deficient red cell populations in patients with lymphoproliferative syndromes.
INTRODUCTION: Paroxysmal nocturnal hemoglobinuria is an acquired clonal stem cell disorder characterized by the decrease or absence of glycosylphosphatidylinositol-anchored molecules from the surface of the affected cells, such as CD55 and CD59, resulting in chronic intravascular hemolysis, cytopenia and increased tendency to thrombosis. PNH-phenotype has been described in various hematological disorders, mainly in aplastic anemia and myelodysplastic syndromes, while it has been reported that complete deficiency of CD55 and CD59 has also been found in patients with lymphoproliferative syndromes, like non-Hodgkin's lymphomas. MATERIALS AND METHODS: The presence of CD55- and/or CD59-defective red cell populations was evaluated in 217 patients with lymphoproliferative syndromes. The study population included 87 patients with NHL, 55 with HD, 49 with CLL, 22 with ALL and four with hairy cell leukemia. One hundred and twenty-one healthy blood donors and seven patients with PNH were also studied as control groups. The sephacryl gel microtyping system was performed for the detection of CD55- and CD59-deficient red cell populations. Ham and sucrose lysis tests were also performed in all samples with CD55 or CD59 negative populations. RESULTS: Red cell populations deficient in both CD55 and CD59 molecules were detected in 9.2% of patients with lymphoproliferative syndromes (more often in ALL and nodular sclerosis type of HD) and in all PNH patients. CD55-deficient red cell populations were found in 8.7% of LPS patients (especially in low grade B-cell NHL), while CD59-deficient populations were found in only two patients with low grade B-cell NHL. CONCLUSION: These data indicate a possible association between paroxysmal nocturnal hemoglobinuria phenotype and lymphoproliferative syndromes, while further investigation is necessary to work out the mechanisms and the significance of the existence of this phenotype in these patients.
Adolescent↗
Erythropoietic response to hypoxaemia in diffuse idiopathic pulmonary fibrosis, as opposed to chronic obstructive pulmonary disease.
The aim of this study was to assess the erythropoietic response to hypoxaemia in patients with diffuse idiopathic pulmonary fibrosis (DIPF), and to speculate on the underlying mechanisms. Patients on an established chronic respiratory failure due to DIPF or chronic obstructive pulmonary disease (COPD) were studied. The erythropoietic response to hypoxaemia in both conditions was assessed. We studied 18 patients with DIPF and 29 patients with COPD in respiratory failure in a stable stage, free from acute infection and congestive heart failure. Blood gases, erythrocytic parameters, as well the serum levels of iron, ferritin and erythropoietin were determined. All the DIPF patients studied, apart from two, had normal or subnormal haematocrit values. The patients with COPD had an inconsistant response to hypoxaemia; 12 had normal or subnormal haematocrit values and the remaining 17 were erythraemic. The mean value of erythropoietin (EPO) in both DIPF and COPD patients was significantly higher than normal. In conclusion, patients with DIPF exhibit a lack of erythropoietic response to hypoxaemia, despite the augmented erythropoietin levels. This may reflect a defective bone marrow erythropoietic response in DIPF patients. It is suggested that the pathophysiology of DIPF underlies this mechanism.
Adult↗
Multilocalized pyomyositis in a previously healthy subject.
A case of pyomyositis is presented. This case is unique in the literature as at least 29 abscesses were detected, affecting the vast majority of big muscle groups. We outline the origin of this disease entity which selectively affects striated muscles. We also discuss its natural history and management strategy.
Aged↗
Comparative antiplatelet efficacy of a novel, nonpeptide GPIIb/IIIa antagonist (XV454) and abciximab (c7E3) in flow models of thrombosis.
Glycoprotein (GP) IIb/IIIa is pivotal in homotypic platelet aggregation and may also be involved in the heterotypic adhesion of leukocytes and tumor cells to platelets. This study was primarily undertaken to compare the antiplatelet efficacy of a novel, nonpeptide GPIIb/IIIa antagonist, XV454, to that of abciximab in 2 flow models of platelet thrombus formation: (1) direct shear-induced platelet aggregation imposed by a cone-and-plate rheometer and (2) platelet adhesion onto von Willebrand factor (vWF)/collagen I followed by aggregation in a perfusion system. XV454 inhibited platelet aggregation in a concentration-dependent manner in both experimental models. Maximal inhibition of aggregation was achieved by XV454 at approximately 70% receptor occupancy, which is lower than the >/=85% previously reported for abciximab. At similar levels of receptor blockade (approximately 45%), XV454 appeared to be relatively more effective than abciximab in suppressing platelet aggregation. Neither XV454 nor abciximab inhibited platelet adhesion to collagen. Pretreatment of surface-adherent platelets with either XV454 or abciximab inhibited the attachment of monocytic THP-1 cells under flow. In contrast, the rapidly reversible GPIIb/IIIa inhibitor orbofiban failed to suppress these heterotypic interactions. These findings demonstrate that XV454 is a potent GPIIb/IIIa antagonist with a long receptor-bound lifetime like abciximab and may be beneficial for the treatment/prevention of thrombotic complications.
Abciximab↗
Detection of CD55 and/or CD59 deficient red cell populations in patients with aplastic anaemia, myelodysplastic syndromes and myeloproliferative disorders.
Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired clonal stem cell disorder characterized by intravascular haemolysis, venous thrombosis, marrow hypoplasia, frequent episodes of infection, and rarely leukaemic conversion. At the cellular level, PNH is characterized by the decrease or absence of glycosylphosphatidylinositol (GPI)-anchored molecules, such as CD55 and CD59, from the cell surface. PNH-like clones have been described in various haematological disorders. The link between PNH and aplastic anaemia (AA) has been established but the relationship of PNH with myelodysplastic syndromes (MDS) or myeloproliferative disorders (MPD) remains unclear. In this study, the presence of CD55 and/or CD59 defective (PNH-like) red cell populations was evaluated in 21 patients with AA, 133 with MDS, 197 with MPD, 7 with PNH and in 121 healthy blood donors using the Sephacryl Gel Test microtyping system. Red cell populations deficient in both molecules CD55 and CD59 were detected in 33.3% of AA patients, in 16.5% of MDS patients (50% with hypoplastic bone marrow), in 14.2% of MPD patients (more often in essential thrombocythemia, 21.2%) and in all PNH patients. CD55 deficient red cell populations were found in 14.2% of patients with AA, 12.7% of patients with MDS and 21.3% of patients with MPD. CD59 deficient populations were found in 9.5% of AA patients, 2.2% of MDS patients and 2% of MPD patients. These results indicate an association between PNH, AA and MDS or even between PNH and MPD. Further investigation is necessary to work out the mechanisms of this association, and to define classification criteria for borderline cases, where diagnosis is difficult.
Anemia, Aplastic↗
Multiple myeloma in sickle cell syndromes.
Multiple myeloma (MM) is rare among patients with sickle cell syndromes (SCS). We describe six Greek sickle cell patients aged 56 to 65 years: five haemoglobin Sbeta+thalassaemia (HbSbeta+ (thal), one sickle cell anaemia (HbSS), who developed MM (three IgGkappa, one IgGlambda, one IgAkappa, and one IgGK-IgAK (biclonal). Our HbSbeta+thal cases, represent the first reported association of this entity with MM. Generalized bleeding diathesis, stroke, grand mal seizures, bone marrow necrosis and other clinical manifestations due to hyperviscosity aggravated by sickle cell vasoocclusion were treated by plasmaphereses and exchange blood transfusions. The increase of mean survival in SCS patients due to the current medical facilities may have an impact on the incidence of MM among them, if a pathogenetic link between the two conditions exists. All our patients carried a diagnosis of cholelithiasis which may predispose to MM; two of them progressed from a monoclonal gammopathy of undetermined significance (MGUS) to MM. Further studies are needed in order to understand the relationship between SCS and MM.
Adult↗
Clinical significance of the molecular detection of melanoma cells circulating in the peripheral blood in melanoma patients.
BACKGROUND: Blood circulating melanoma cells may be important for the spread of the disease. The current methods are not sensitive in detecting micro metastases. Tyrosinase mRNA can be detected in peripheral blood by a molecular test. As tyrosinase is expressed only in melanocytes and melanocytes normally do not circulate in the blood, the test may prove reliable in detecting circulating melanoma cells. METHODS EXPERIMENTAL DESIGN: we used a reverse-transcription polymerase chain reaction (RT-PCR) detecting tyrosinase mRNA in the blood. A prospective investigation in melanoma patients undergoing surgery was conducted; follow-up duration was 12 months. SETTING: University Department Laboratory and Melanoma Clinic of a Tertiary Hospital. PATIENTS: a total of 27 Greek patients with a diagnosis of malignant melanoma at different stages of the disease; 12 months follow-up after surgery. Samples form 12 healthy volunteers and 13 patients with chronic myelogenous leukemia served as controls. INTERVENTIONS: none. MEASURES: none. RESULTS: We detected mRNA tyrosinase in the peripheral blood in 16 out of 27 melanoma patients studied. No tyrosinase mRNA was detected in any of the 25 samples from the controls. Two of the 16 positive cases developed a metastasis within the next 12 months following testing. The other 14 positive cases remain metastasis free for this period, as also did the test negative cases. CONCLUSIONS: Detection of blood circulating melanoma cells by a RT-PCR technique, may be helpful in defining melanoma patients who are at risk for the spread of the disease.
Adult↗
Familial Mediterranean fever phenotype II in Greece.
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Aged↗
Antiplatelet therapies: platelet GPIIb/IIIa antagonists and beyond.
Accumulating evidence supports the critical role of platelet involvement in arterial thrombosis, and argues for the development of more efficacious, yet safe, antiplatelet therapies. Aspirin continues to be used routinely for the management of acute myocardial infarction, unstable angina and secondary prevention of ischemic events. Nevertheless, adverse clinical outcomes still occur. Newer-generation drugs such as clopidogrel (an adenosine-diphosphate receptor antagonist) and intravenous glycoprotein (GP)IIb/IIIa antagonists (inhibitors of platelet aggregation irrespective of the stimulus) have demonstrated significant clinical benefit. This review will discuss the role of the aforementioned antiplatelet therapies in thrombotic disorders as well as future directions in the field.
Animals↗
CCR3-active chemokines promote rapid detachment of eosinophils from VCAM-1 in vitro.
Selective eosinophil recruitment is the result of orchestrated events involving cell adhesion molecules, chemokines, and their receptors. The mechanisms by which chemokines regulate eosinophil adhesion and migration via integrins are not fully understood. In our study, we examined the effect of CCR3-active chemokines on eosinophil adhesion to VCAM-1 and BSA under both static and flow conditions. When eotaxin-2 or other CCR3-active chemokines were added to adherent eosinophils, it induced rapid and sustained eosinophil detachment from VCAM-1 in a concentration-dependent manner. Adhesion was detectably reduced within 3 min and was further reduced at 10-60 min. Simultaneously, eotaxin-2 enhanced eosinophil adhesion to BSA. Preincubation of eosinophils with the CCR3-blocking mAb 7B11 completely prevented chemokine-induced changes in adhesion to VCAM-1 and BSA. Using a different protocol, pretreatment of eosinophils with chemokines for 0-30 min before their use in adhesion assays resulted in inhibition of VCAM-1 adhesion and enhancement of BSA adhesion. By flow cytometry, expression of alpha4 integrins and a beta1 integrin activation epitope on eosinophils was decreased by eotaxin-2. In a flow-based adhesion assay, eotaxin-2 reduced eosinophil accumulation and the strength of attachment to VCAM-1. These results show that eotaxin-2 rapidly reduced alpha4 integrin function while increasing beta2 integrin function. These findings suggest that chemokines facilitate migration of eosinophils by shifting usage away from beta1 integrins toward beta2 integrins.
Actins↗
Immobilized platelets support human colon carcinoma cell tethering, rolling, and firm adhesion under dynamic flow conditions.
Accumulating evidence suggests that successful metastatic spread may depend on the ability of tumor cells to undergo extensive interactions with platelets. However, the mechanisms mediating tumor cell adhesion to platelets under conditions of flow remain largely unknown. Therefore, this study was designed to analyze the ability of 3 human colon carcinoma cell lines (LS174T, COLO205, and HCT-8) to bind to surface-anchored platelets under flow and to identify the receptors involved in these processes. Immobilized platelets support LS174T cell adhesion at wall shear stresses up to 1.4 dyn/cm(2). Our data suggest that platelets primarily recruit LS174T cells through a 2-step, sequential process of adhesive interactions that shares common features but is distinct from that elaborated for neutrophils. Platelet P-selectin mediates LS174T cell tethering and rolling in a PSGL-1- and CD24-independent manner. Moreover, platelet alpha(IIb)beta(3)-integrins appear to be capable of directly capturing LS174T cells from the fluid stream, and also convert instantaneously transient tethers initiated by P-selectin into stable adhesion. This step is at least partially mediated by von Willebrand factor, but not fibrinogen or fibronectin, that bridges platelet alpha(IIb)beta(3) with a yet unidentified receptor on the LS174T cell surface via an RGD-dependent mechanism. The sequential engagement of platelet P-selectin and alpha(IIb)beta(3) is also requisite for the optimal adhesion of COLO205. Furthermore, HCT-8 cells, which fail to interact with P-selectin, tether minimally to surface-anchored platelets under flow, despite their extensive adhesive interactions under static conditions. This cascade of events depicts an efficacious process for colon carcinoma arrest at sites of vascular injury. (Blood. 2000;96:1789-1797)
Biomechanical Phenomena↗