Acquired von Willebrand syndrome in congenital heart disease surgery: results from an observational case-series.

Essentials Bleeding complications during congenital heart disease surgery in neonatal age are very common. We report the perioperative incidence of acquired von Willebrand syndrome (aVWS) in 12 infants. aVWS was detected in 8 out of 12 neonates and infants intraoperatively after cardiopulmonary bypass. Ten patients received von Willebrand factor concentrate intraoperatively and tolerated it well. SUMMARY: Background Cardiac surgery of the newborn and infant with complex congenital heart disease (CHD) is associated with a high rate of intraoperative bleeding complications. CHD-related anatomic features such as valve stenoses or patent arterial ducts can lead to enhanced shear stress in the blood stream and thus cause acquired von Willebrand syndrome (aVWS). Objective To evaluate the intraoperative incidence and impact of aVWS after cardiopulmonary bypass (CPB) in neonates and infants with complex CHD. Patients/Methods We conducted a survey of patients aged < 12 months undergoing complex cardiac surgery in our tertiary referral center. Twelve patients, whose blood samples were analyzed for aVWS before CPB and immediately after discontinuation of CPB on a routine basis, were eligible for the analysis. von Willebrand factor antigen (VWF:Ag), ristocetin cofactor activity (VWF:RCo), collagen binding activity (VWF:CB), VWF:multimers and factor VIII activity (FVIII:C) were determined. Results aVWS was diagnosed by VWF multimer analysis in 10 out of 12 patients (83%) prior to surgery and intraoperatively at the end of CPB in 8 out of 12 patients (66%). Ten patients received VWF/FVIII concentrate intraoperatively as individual treatment attempts during uncontrolled bleeding. They tolerated it well without intraoperative thrombotic events. One patient suffered a transient postoperative cerebral sinuous vein thrombosis. Conclusions aVWS is of underestimated incidence in complex CHD surgery. These data may offer a new approach to reduce the risk of severe bleedings and to achieve hemostasis during high-risk pediatric cardiac surgery by tailoring the substitution with von Willebrand factor concentrate.

Aspirin non-responder status in patients with recurrent cerebral ischemic attacks.

BACKGROUND: Antiplatelet agents such as acetylsalicylic acid (aspirin) reduce the relative risk for cerebrovascular events in patients with cardiovascular or cerebrovascular disorders by approximately 23 %. Recent observations raise the possibility that aspirin resistance may contribute to the failure of aspirin treatment in a significant proportion of patients (aspirin non-responders). To evaluate the clinical relevance of aspirin non-responder status, we analysed platelet functions in symptomatic and asymptomatic patients treated with aspirin for secondary prevention of cardiovascular and cerebrovascular events. METHODS: A total of 53 patients on 100 mg aspirin daily for secondary prevention (mean treatment duration > 60 months) were included. Patients were categorized as asymptomatic if they were free of cerebrovascular incidents for at least 24 months (n = 18). Symptomatic patients had suffered ischemic strokes or transient ischemic attacks within the previous 3 days (n = 35). Platelet function was assessed using the PFA-100 system that allows for quantitative assessment of platelet function, reporting platelet aggregatability as the time required to close a small aperture in a biologically active membrane. RESULTS: Collagen/epinephrine closure times were significantly shorter in symptomatic patients than in asymptomatic patients (p < 0.01). Individual closing times were normal in 12 of 35 symptomatic patients (34 % non-responders) whereas all asymptomatic patients had prolonged closure times. CONCLUSIONS: Aspirin non-responder status may contribute to failure of aspirin therapy in the secondary prevention of cerebrovascular incidents in as much as 30-40 % of patients. Quantitative assessment of platelet functions may provide a means to predict aspirin treatment failure in individual patients and to re-direct therapeutic strategies.

Evidence for a lymphotropic nature of circulating plasmacytoid monocytes: findings from a case of CD56+ chronic myelomonocytic leukemia.

Because the cells previously designated plasmacytoid T cells share major immunophenotypic features with cells of the mononuclear-phagocyte system, they have been re-named and are now known as plasmacytoid monocytes (PM). We describe a unique case of chronic myelomonocytic leukemia with circulating PM. The patient, a 48-year-old man, presented initially with refractory anemia. Four years later his general condition deteriorated, accompanied by an increase in leukocytes to 200,000/microliters blood. The bone marrow histology was interpreted as compatible with a diagnosis of chronic myelomonocytic leukemia. Two months before he died, the patient developed generalized lymphadenopathy clinically simulating malignant lymphoma. Histologic examination of an axillary lymph node revealed diffuse infiltration by PM. The PM in the lymph node and some circulating cells closely resembling PM expressed L-selectin, a finding that could be interpreted as a morphologic correlate of their marked lymphotropism. The detection of large numbers of CD56/CD33 double-positive circulating blast cells by FACS analysis strongly supported the diagnosis of a leukemia of myelogenous origin. The patient died of tumor cachexia. Autopsy revealed widespread leukemic infiltrates (always containing clusters of PM) in bone marrow, spleen, liver, lymph nodes, and mucosa-associated lymphoid tissue of the oropharynx. The final diagnosis was one of chronic myelomonocytic leukemia with marked lymphotropism and partial differentiation towards PM. We consider that the rare instances of a hematologic tumor with differentiation towards PM should be classified amongst the myelogenous leukemias.

Fish oil preparations rich in docosahexaenoic acid modify platelet responsiveness to prostaglandin-endoperoxide/thromboxane A2 receptor agonists.

The effects of daily dietary supplementation for 6 weeks with either 4.5 g eicosapentaenoic acid (EPA) and 3.35 g docosahexaenoic acid (DHA) (group I, EPA/DHA = 1.33) or 3.5 g EPA and 6.4 g DHA (group II, EPA/DHA = 0.54) on platelet responsiveness to the stable prostaglandin (PG)-endoperoxide analogue 9,11-dideoxy,9 alpha-11 alpha-methanoepoxy-PGF2 alpha (U 46619) were studied in healthy volunteers. Dose-response curves (DRC) of U 46619-induced platelet aggregation were analysed by computerized non-linear curve fitting. In group I, the concentration of U 46619 required for half-maximum platelet aggregation (EC50) remained unchanged, whereas the Hill coefficient decreased from 6.2 to 3.3 (P < 0.02). In group II, characterized by a high intake of DHA, a considerable increase of EC50 from 0.3 to 1.4 microM was found (P < 0.02). These results suggest different effects of EPA and DHA on the platelet thromboxane/endoperoxide-amplifying system. The considerable shift of the DRC in group II suggests a direct effect of DHA on the presentation of the endoperoxide receptor and/or post-receptoral events.

Platelets from patients with liver cirrhosis exhibit a defect in the von Willebrand factor-binding domain.

In this study, we examined the platelet von Willebrand factor (vWF)-binding domain in patients with liver cirrhosis. Direct binding studies were performed with the monoclonal antibody (mab) AN51 with specificity for the glycoprotein (GP) lb alpha. Specific binding of AN51 to intact washed platelets was monitored by an enzyme-linked immunoassay (ELISA). Half-maximum binding to intact washed platelets occurred at concentrations as low as 94 +/- 24 ng/ml; N = 12). Binding saturation analysis of with AN51 revealed a more than fifty percent reduction of AN51-binding sites (p < 0.001) in cirrhosis (N = 13) as compared to sex- and age-matched healthy controls (N = 12). These data demonstrate an impairment of the platelet surface vWF-binding domain in patients with liver cirrhosis. The resulting defect in primary haemostasis, i.e. the vWF-mediated attachment of platelets to the exposed subendothelium, is expected to contribute to the increased risk of haemorrhagic complications in these patients.

Intracellular cytosine arabinoside accumulation and cytosine arabinoside triphosphate formation in leukemic blast cells is inhibited by etoposide and teniposide.

Cytosine arabinoside (ara-C) is one of the most active compounds in the treatment of acute leukemias. In the majority of current protocols ara-C is combined with other cytotoxic agents in an attempt to increase antileukemic activity. The present study investigated the impact of etoposide, teniposide, amsacrine, mitoxantrone, anthracyclines, and asparaginase on the cellular accumulation of ara-C and its intracellular metabolism in order to provide a better rationale for combination therapy. Intracellular accumulation and phosphorylation of ara-C were determined in peripheral blast cells from twenty patients with acute leukemias after exposure to 1 and 10 mumol/l ara-C alone and after preincubation with 1 and 10 micrograms/ml etoposide, 10 and 100 micrograms/ml teniposide, 10 mumol/l amsacrine, 500 ng/ml mitoxantrone (or daunorubicin or doxorubicin) or 10 mumol/l asparaginase. Ara-C accumulation at 10 mumol/l was decreased by 1 microgram/ml etoposide (67 +/- 18% of control), 10 micrograms/ml etoposide (30 +/- 22%), 10 micrograms/ml teniposide (12 +/- 23%), 100 micrograms/ml teniposide (10 +/- 18%), and amsacrine (51 +/- 21%). Intracellular ara-CTP formation was determined at an extracellular concentration of 10 mumol/l and preincubation with these drugs. The intracellular formation of ara-CTP was decreased by 1 microgram/ml etoposide (77 +/- 15% of control), 10 micrograms/ml etoposide (32 +/- 22%), 10 micrograms/ml teniposide (10 +/- 9%), 100 micrograms/ml teniposide (0 +/- 0%), but not by amsacrine. These data indicate that prior exposure to etoposide and teniposide influence ara-C metabolism and possibly cytotoxicity, and thus should not immediately precede ara-C administration in clinical trials.

Platelet endoperoxide/thromboxane A2 (PGH2/TXA2) receptors in patients with myeloproliferative disorders.

In patients with myeloproliferative disorders (MPD) an altered sensitivity of platelets to antiaggregatory prostaglandins and to the endoperoxide analogue U 46619 has been found. In this study we examined U 46619-induced platelet aggregation and binding of the endoperoxide/thromboxane A2 (TXA2) receptor antagonist SQ 29548 in 11 patients with MPD and 11 healthy controls. Although platelet responsiveness to U 46619 was significantly enhanced (p less than 0.05) in MPD, binding affinity and binding capacity of the corresponding endoperoxide/TXA2 receptor were not altered (Bmax 0.67 +/- 0.20 vs. 0.58 +/- 0.14 pmol/10(9) platelets, Kd 0.41 +/- 0.11 vs. 0.55 +/- 0.09 nM). These data exclude the possibility that changes in the presentation of endoperoxide/TXA2 receptors are responsible for the enhanced platelet sensitivity to endoperoxides found in MPD.

The anti-fungal agent itraconazole exerts immunosuppressive effects on alloreactivity but not on natural immunity in vitro.

The anti-fungal azole drug itraconazole was compared with fluconazole regarding immunosuppressive effects in a model of human alloreactivity in vitro (the mixed lymphocyte culture, MLC) and in assays of non-adaptive immunity (natural killing, NK, and lymphokine activated killing, LAK). Itraconazole, but not fluconazole, strongly inhibited lymphocyte proliferation and the generation of allospecific cytolytic activity, but had no effect on the development of major histocompatibility complex (MHC)-unrestricted ("natural killer-like") cytotoxicity or of alloindifferent suppressive activity in MLC. Neither drug blocked LAK cell induction, nor the effector phase of either NK or LAK activity. These results suggest that itraconazole might represent a new class of immunosuppressive agent which specifically blocks alloreactivity without affecting natural immunity.

Comparison of the immunosuppressive activities of the antimycotic agents itraconazole, fluconazole, ketoconazole and miconazole on human T-cells.

Four antifungal agents have been screened in vitro for their immunosuppressive effects on proliferative responses in human mixed lymphocyte cultures (MLC). A hierarchy of inhibitory activity was observed, where itraconazole was greater than ketoconazole greater than miconazole greater than fluconazole, with itraconazole as suppressive as cyclosporin A, and fluconazole completely without suppressive activity. The mechanism of inhibition did not involve blockade of T-cell growth factor production and, consistent with this, interleukin-2-dependent T-cell clone proliferation was blocked by these agents in the same order of decreasing activity as in MLC. The secretion of cytokines without known T-cell growth factor activity (interferon-gamma, tumour necrosis factor-alpha) was also not significantly blocked by these agents. These results therefore demonstrate that antifungal azole drugs may be variably strongly immunosuppressive for human T-lymphocyte proliferation in vitro, but none appear to be so via a mechanism involving inhibition of cytokine secretion.

Effects of novel antifungal azole derivatives on the 5-lipoxygenase and cyclooxygenase pathway.

5-Lipoxygenase and cyclooxygenase catalyze the first steps of the conversion of arachidonic acid into leukotrienes and prostanoids, respectively. Leukotrienes are important mediators of inflammation and thromboxanes are mainly involved in platelet functions. The effects of the new antimycotic drugs, itraconazole and fluconazole, on the 5-lipoxygenase pathway in human polymorphonuclear leukocytes (PMNL), on the eicosanoid metabolism in platelets, platelet aggregation and on cyclooxygenase activity were investigated and compared with miconazole and ketoconazole. Itraconazole inhibited the formation of 5-lipoxygenase metabolites in human PMNL (IC50 = 2 x 10(-6) mol/l), while it had no effect on cyclooxygenase and platelet aggregation at concentrations up to 10(-4) mol/l and 10(-5) mol/l, respectively. Fluconazole was ineffective in all assays. Miconazole inhibited thromboxane synthase (IC50 = 1 x 10(-5) mol/l) and platelet aggregation (IC50 = 3 x 10(-5) mol/l). Ketoconazole was less active in this respect (IC50 for platelet aggregation = 2 x 10(-4) mol/l). All compounds did not affect cyclooxygenase activity in concentrations up to 10(-4) mol/l in the pure enzyme assay. These results indicate that among the tested azoles two compounds show remarkable effects. Miconazole inhibits thromboxane synthesis and itraconazole is a potent inhibitor of leukotriene formation which has only minor effects on the cyclooxygenase pathway. This finding is of considerable interest regarding the application of itraconazole during immunosuppressive therapy and suggests further studies of its potential antiphlogistic properties.

[Rocky Mountain spotted fever]. / Rocky-Mountain-Fleckfieber.

After returning from a holiday in the USA a 24-year-old man fell ill with diarrhoea, high fever and marked rash including the palms of the hands and soles of the feet. When a history of a tick bite in the USA was elicited, a rickettsial infection was suspected. Treatment with doxycycline, 100 mg twice daily, was instituted finally and the fever slowly resolved. The patient became completely well again within four weeks. Serological tests confirmed the diagnosis of Rocky Mountain spotted fever.

[Transplantation of bone marrow from unrelated donors in chronic myeloid leukemia]. / Transplantation von Knochenmark unverwandter Spender bei chronischer myeloischer Leukämie.

Bone marrow transplantations in four patients (aged 8-28 years, median 27 years) with chronic myeloid leukaemia (CML) were performed from unrelated donors who were HLA-identical and MLC-negative. One patient was in the stage of refractory blast crisis, one in a chronic phase, and two in the second chronic phase. Conditioning treatment consisted of fractionated radiation and administration of cyclophosphamide; in the patients with their second chronic phase additionally etoposide. Cyclosporin A and methotrexate were administered to prevent graft versus host reaction. The patient in the blast crisis died on day 12 after transplantation of Candida pneumonia. The other three patients are still alive 128, 306 and 530 days, respectively, after transplantation, only a mild form of graft versus host disease having occurred. It is suggested that for patients younger then 50 years with CML in the chronic phase an unrelated donor should be searched for in the absence of a familial donor.