Ineffectiveness of interferon-gamma in the treatment of idiopathic myelofibrosis: a pilot study.

It has been proposed that interferon-gamma (IFN) inhibits collagen synthesis in myeloproliferative disorders through an inhibitory effect on PDGF and TGF-beta. We therefore evaluated the role of IFN-gamma on bone marrow fibrosis in idiopathic myelofibrosis (IMF). After a 3-month observation period, nine patients (five female, four male), median age 64 years (range 43-72 years), received 3 x 3 mU IFN-gamma/week over 6 months and were monitored after withdrawal of IFN-gamma for further 3 months. Three out of nine patients have completed the study according to the protocol. Six patients had to be withdrawn from IFN-gamma due to the following reasons: bacterial infection (three patients), splenic infarction or deterioration of splenomegaly (one patient, each) and refusal to continue IFN-gamma (one patient). Results from seven patients treated for at least 8 weeks were considered measurable. Leukopenia, initially present in one of the evaluated patients, deteriorated during IFN-gamma treatment. This patient died during the observation period shortly after withdrawal of the therapy as a result of septicemia. Transfusion-dependent anemia, initially observed in two of the evaluated patients, deteriorated during the IFN-gamma treatment. Bone marrow fibrosis increased in three patients, whereas it remained unchanged in another and improved in a further patient. Splenomegaly improved in two patients but deteriorated markedly in one. Taking these observations together, four patients had disease progression during IFN-gamma treatment, two had stable disease and one could be qualified as a partial responder. According to these data IFN-gamma cannot be considered as a treatment option for patients with IMF.

The decanucleotide polymorphism in the factor VII promoter predicts factor VII plasma levels but not the risk of acute coronary syndromes.

It is known from large epidemiological studies that the elevation of coagulation factor VII in plasma is an independent risk factor for acute coronary syndromes. The level of factor VII is influenced by polymorphic sites in the factor VII gene. However, data on the association of such polymorphisms with the risk of acute coronary syndromes are conflicting. A decanucleotide insertion/deletion polymorphic site has been described in the promoter of the factor VII gene that leads to a dramatic change in the plasma factor VII levels. We therefore analyzed the association of this polymorphism with the risk of acute coronary syndromes in a case-control study. Included in the study were 111 patients with angiographically documented acute coronary syndromes and 108 age- and sex-matched individuals from the same geographic area without signs or symptoms of coronary heart disease. The presence or absence of the decanucleotide stretch at position -323 in the promoter of factor VII was monitored using a polymerase chain reaction (PCR)-based restriction technique. The prevalence of the genotype with the homozygous deletion was similar in the patients with acute coronary syndromes (79.2%) and in the control patients (79.6%). There was a non-significant trend toward a higher prevalence of the homozygote deletion in patients with premature acute coronary syndromes (77.4%) compared with an age-matched subgroup of the control patients (67. 5%) (odds ratio [OR] 1.6, confidence interval [CI] 0.95, 0.61-3.93). Thus, we could not find a significant association of the occurrence of acute coronary events with the insertion/deletion polymorphism in factor VII.

A prospective controlled trial comparing weekly self-testing and self-dosing with the standard management of patients on stable oral anticoagulation.

Oral anticoagulant therapy requires frequent laboratory controls of its intensity to assure therapeutic efficacy and to prevent potentially life threatening adverse events. It is generally assumed, that increasing the frequency of testing would lead to a better control of anticoagulation. We tested this hypothesis in a prospective controlled trial comparing weekly self-testing and self-dosing (self management) with the standard-management of these patients in an anticoagulation clinic. Only patients with stable anticoagulation were included into the study. We recorded 2733 weekly determinations of the intensity of anticoagulation (INR) in 49 patients on self-testing and self-dosing and 539 determinations of the INR in 53 patients on standard-management. Two intensities of anticoagulation were used in each group: a target INR of 3.5 for patients with artificial heart valves (target range: 2.5-4.5) and a target INR 2.5 (target range: 2.0-3.0) for patients with atrial fibrillation or venous thromboembolism. The deviation from the target INR, the fraction of INR determinations within the preset therapeutic range and the difference between the target INR and the actually achieved mean INR were the three major endpoints of the study. The mean deviation from the target INR was smaller in the groups of patients on self-management compared to the patients on standard-management. Individual deviations were significantly (p <0.0001) dependent on the type of management in interaction with the treatment intensity in a general linear model. Patients on weekly self-testing and self-dosing had more INR values within the therapeutic range than patients on standard-management (86.2% vs. 80.1% at INR range 2.5-4.5; 82.2 vs. 68.9 at INR range 2.0-3.0). The achieved mean INR was almost identical with the target INR in the patients on self-management but was significantly (p <0.005) below the target INR in the high intensity anticoagulation group on standard-management (target INR:3.5; achieved mean INR: 3.19; CI 0.95: 3.05-3.34). Our data show, that weekly self-testing and self-dosing leads to a better control of anticoagulation than standard treatment in an anticoagulation clinic.

The impact of Glu102Lys on the factor X function in a patient with a doubly homozygous factor X deficiency (Gla14Lys and Glu102Lys).

Two homozygous point mutations were found in a patient with factor X (FX) deficiency; One results in substitution of Lys for Gla+ 14 and the second causes a Lys substitution for Glu102. The proposita has a severely reduced FX coagulant activity in the extrinsic (<1% of normal) and in the intrinsic (30% of normal) system of coagulation and after activation with Russel's viper venom (18% of normal). The FX antigen is reduced in this patient to 20% of normal. The substitution of Lys for Glu102 in FX deficiency has been reported previously in a heterozygous state in conjunction with a Lys for Gla+14 substitution and with a Pro for Ser334 substitution. The contribution of the Lys for Glu102 substitution in the observed combined FX defect in these patients was unclear. The mutation causing the Glu102Lys substitution was introduced by site directed mutagenesis into a wild-type FX cDNA, and recombinant protein was expressed in HEK 293 cells. Compared to the wild-type FX cDNA, the mutant construct had a 67% activity upon activation in the extrinsic system, 93% activity upon activation in the intrinsic system and 72% after activation with RVV. The data presented show that the substitution of Lys for Glu102 results in a minor functional defect of the FX molecule.

Elevated activation markers of coagulation in patients undergoing orthognathic surgery.

Surgery is associated with a variable but increased incidence of postoperative venous thromboembolism (VTE). The risk of VTE after orthognathic surgery is unknown. Recently developed assays for activation markers of blood coagulation allow the detection of a prethrombotic state and may thus help to identify surgical procedures with a risk of postoperative VTE. The pre- and postoperative levels of thrombin-antithrombin complex (TAT) and prothrombin fragment 1+2 (F1+2) were studied in ten patients undergoing orthognathic surgery. Mean levels of TAT and F1+2 were within the normal range preoperatively (TAT:2.6+1.0 microg/L, F1+2:0.8+0.2 nmol/L). A significant increase in both parameters occurred postoperatively (TAT:21.8+21.4 microg/L, P<0.005; F1+2:1.3+0.4, P<0.02). No increase was observed in a control group (n=13) consisting of patients undergoing minor surgical procedures in general anesthesia. Our study shows that a marked activation of the coagulation cascade occurs during orthognathic surgery which warrants further studies on the true incidence of postoperative VTE in patients undergoing orthognathic surgery.

Factor X Frankfurt I: molecular and functional characterization of a hereditary factor X deficiency (Gla+25 to Lys).

A family with hereditary factor X deficiency is presented. One member, a 25-year-old man, showed a mild bleeding tendency. His factor X activity (extrinsic: 56%; intrinsic: 55%; Russell's viper venom: 57%) and his level of circulating factor X antigen (55% of normal) were markedly reduced. Analysis of his factor X gene revealed a single point mutation within exon II resulting in the substitution of +25 Gla (GAA) by Lys (AAA). The mutation was determined by gene analysis to be heterozygous in this patient, his mother and one of his brothers. Clotting assays of factor X purified from the plasma of the index patient revealed an activity of 89% of normal upon activation with Russell's viper venom, 77% of normal in the intrinsic and 81% of normal in the extrinsic coagulation pathway. The mutation responsible for the substitution of Lys for Gla+25 was introduced into an expression plasmid containing a wild type factor X cDNA and expressed in a mammalian cell line. Factor X antigen levels in the cell lysates and in the supernatant were identical in the mutant and wild type constructs. The specific activity of the factor X expressed from the mutant construct was 3% compared with the wild type construct. These data demonstrate that the substitution of Lys for Gla+25 results not only in a reduced level of factor X in the affected family members, but also in a substantial loss of specific factor X activity.

Reduction of net photosynthesis in oats after treatment with low concentrations of ozone.

Oats (Avena sativa L. cv Titus) were exposed to low concentrations of O3 in an assimilation chamber system. Net photosynthesis (net CO2 uptake), measured before and after O3 fumigation, showed significantly different responses for leaves of different age. The oldest active leaf was the most sensitive to O3. Net photosynthesis was depressed after 2 h with 0.075 ppm (150 microg m(-3)) O3. For leaves exposed to 0.150 ppm (300 microg m(-3)) O3 for 2 h, net photosynthesis was reduced significantly for 4 h, after which recovery occurred, nearly reaching the preexposure level 19 h after the exposure. Dark respiration was initially more than doubled after exposure to 0.130 ppm (260 microg m(-3)) O3. There was no visible injury after any of the experiments. The results indicate that O3 may cause crop losses through effects on photosynthesis even in Scandinavia, where a typical O3 episode lasts 1 to 2 h, and the concentration seldom exceeds 0.150 ppm.

Effect of ozone on net photosynthesis in oat (Avena sativa) and duckweed (Lemna gibba).

Short exposure to ozone depressed photosynthesis in both oat and duckweed at concentrations above 140 microg m(-3) and 300 microg m(-3), respectively. The effect on exposed oat flag leaves was age-dependent, with maximum susceptibility to ozone 10-20 days after emergence of the panicle. In duckweed, photosynthesis was more sensitive to differences in ozone concentration than to differences in duration of exposure.