Growth parameters and resistance against Drechslera teres of spring barley (Hordeum vulgare L. cv. Scarlett) grown at elevated ozone and carbon dioxide concentrations

Spring barley ( Hordeum vulgare L. cv. Scarlett) was grown at two CO2 levels (400 vs. 700 ppm) combined with two ozone regimes (ambient vs. double ambient) in climate chambers for four weeks, beginning at seedling emergence. Elevated CO2 concentration significantly increased aboveground biomass, root biomass, and tiller number, whereas double ambient ozone significantly decreased these parameters. These ozone-induced reductions in growth parameters were strongly overridden by 700 ppm CO2. The elevated CO2 level increased C : N ratio of the leaf tissue and leaf starch content but decreased leaf protein levels. Exposure to double ambient ozone did not affect protein content and C : N ratio but dramatically increased leaf starch levels at 700 ppm CO2. Resistance against Drechslera teres (Sacc.) Shoemaker was increased in leaves grown at double ambient ozone but was less obvious at 700 ppm than at 400 ppm CO2. Constitutive activities of beta-1,3-glucanase and chitinase were significantly higher in leaves grown at double ambient ozone compared to ambient ozone levels. The sum of methanol-soluble and alkali-released cell wall-bound aromatic metabolites (i.e., C-glycosylflavones and several structurally unidentified metabolites) and lignin contents did not show any treatment-dependent differences.

A twin study of individual differences in perceptual asymmetry

Individual differences in perceptual asymmetry have been associated with individual differences in cognitive abilities, personality characteristics, and psychiatric symptoms, for which between-person variation appears to be genetically influenced. Perceptual asymmetry scores are also associated with direction of handedness, for which between-person variation does not appear to be genetically influenced. To assess whether between-person variation of perceptual asymmetry scores is genetically influenced, we examined asymmetry on a freevision task of face processing, the Chimeric Faces Task (CFT), in a sample of 31 monozygotic (MZ) and 20 same-sex dizygotic (DZ) twin pairs. MZ and DZ within twin-pair resemblances were compared to assess genetic and familial influences on asymmetric hemispheric function. We found that twins within a pair were no more likely to resemble each other than were unrelated individuals. The results suggest that the between-person variation in CFT perceptual asymmetry is not influenced by genes or shared environment.

Influence of ACE inhibition on myocardial damage, the Kallikrein-Kinin system and hemostasis during cardiopulmonary bypass surgery

BACKGROUND

ACE inhibitors may have a cardioprotective effect by enhancing bradykinin levels during cardiopulmonary bypass (CPB). However, ACE inhibition could lead to unwelcome effects on the kallikrein contact phase during CPB (since reduction of kallikrein activity by aprotinin has been shown to be beneficial) and may alter the hemostasis. We examined the effects of ACE inhibitors on intraoperative myocardial damage, kallikrein contact phase and hemostasis in patients undergoing CPB.

METHODS

47 patients randomly received either 20 mg/d enalapril or placebo. Creatine kinase (CK and CK-MB), lactate dehydrogenase (LDH), troponin T (TnT), thrombin-antithrombin III complex (TAT), fibrinogen and kallikrein-like activity were measured before surgery, during and immediately after CPB, at the end of surgery and 1, 3 and 5 days after surgery.

RESULTS

No significant differences between enalapril- and placebo- treated patients concerning CK (318 +/- 38.6 U/l vs. 316 +/- 16.8 U/l), CK-MB, LDH, TnT (1.81 +/- 0.45 ng/ml vs. 1.52 +/- 0.34 ng/ml), TAT, fibrinogen and kallikrein-like-activity could be found during study period.

CONCLUSIONS

Reduction of ischemic injury during CPB is not achieved with ACE inhibitors. However, treatment of patients with ACE inhibitors before and during CPB is fully feasible without side effects affecting the kallikrein contact phase or significant influence on hemostasis.

Clinical and neurochemical effects of fenfluramine in children with autism

Fifteen children with autism were treated with 60 mg d,l-fenfluramine (FEN) or placebo in a double-blind A-B-A protocol followed immediately by double-blind placebo-controlled crossover administration of FEN (total duration 62 weeks). Both biochemical and clinical outcomes were examined. Biochemically, FEN led to an increase in dihydroxyphenylacetic acid (DOPAC) and decreases in whole-blood serotonin (5-HT), plasma norepinephrine (NE), and plasma 3-methoxy-4-hydroxyphenylglycol (MHPG). The decrease in whole-blood 5-HT was seen only during treatment with FEN. However, NE levels did not return to baseline as long as 8 weeks after the first FEN treatment period. Increases in DOPAC were greater during the second FEN treatment period than the first. Persistent changes in catecholamine regulation may be related to previously reported long-term effects on central nervous system 5-HT after FEN. Clinically, FEN led to a modest decrease in parent, but not teacher, ratings of hyperactivity and to a small reduction in sensorimotor abnormalities. Abnormal social and affectual responses also decreased, but this was not directly related to FEN treatment. Effects on cognition were equivocal. Hyperserotonemic subjects did not differ from normoserotonemic subjects in clinical response. Overall, no significant advantage for the use of FEN could be established.

Autistic children and their first-degree relatives: relationships between serotonin and norepinephrine levels and intelligence

Whole-blood serotonin (5-HT) and plasma norepinephrine (NE) were studied in 16 autistic children, 21 siblings of autistic children, and 53 parents of autistic children. Both plasma NE and whole-blood 5-HT were negatively correlated with vocabulary performance. Whole-blood 5-HT and plasma NE did not differ between autistic children with or without histories of self-injurious behavior or decreased pain sensitivity. Eighteen subjects were hyperserotonemic (whole-blood 5-HT greater than 270 ng/ml). For these subjects, plasma NE was significantly higher than for subjects without hyperserotonemia. Seven of 10 families with one hyperserotonemic member had two or more hyperserotonemic members. Observations of familiarity of whole-blood 5-HT suggest that larger-scale and more focused study of whole-blood 5-HT as a possible genetic marker may be productive.

Molecular cloning and functional expression of a stress-induced multifunctional O-methyltransferase with pinosylvin methyltransferase activity from Scots pine (Pinus sylvestris L.)

Formation of pinosylvin (PS) and pinosylvin 3-O-monomethyl ether (PSM), as well as the activities of stilbene synthase (STS) and S-adenosyl-1-methionine (SAM):pinosylvin O-methyltransferase (PMT), were induced strongly in needles of Scots pine seedlings upon ozone treatment, as well as in cell suspension cultures of Scots pine upon fungal elicitation. A SAM-dependent PMT protein was purified and partially characterised. A cDNA encoding PMT was isolated from an ozone-induced Scots pine cDNA library. Southern blot analysis of the genomic DNA suggested the presence of a gene family. The deduced protein sequence showed the typical highly conserved regions of O-methyltransferases (OMTs), and average identities of 20-56% to known OMTs. PMT expressed in Escherichia coli corresponded to that of purified PMT (40 kDa) from pine cell cultures. The recombinant enzyme catalysed the methylation of PS, caffeic acid, caffeoyl-CoA and quercetin. Several other substances, such as astringenin, resveratrol, 5-OH-ferulic acid, catechol and luteolin, were also methylated. Recombinant PMT thus had a relatively broad substrate specificity. Treatment of 7-year old Scots pine trees with ozone markedly increased the PMT mRNA level. Our results show that PMT represents a new SAM-dependent OMT for the methylation of stress-induced pinosylvin in Scots pine needles.

Fibrin specificity and procoagulant effect related to the kallikrein-contact phase system and to plasmin generation with double-bolus reteplase and front-loaded alteplase thrombolysis in acute myocardial infarction

This study was undertaken to compare the effects of reteplase and alteplase regimens on hemostasis and fibrinolysis in acute myocardial infarction (AMI). Thrombolytic treatment in patients with AMI is hampered by paradoxical procoagulant effects that favor early reocclusion. In vivo data comparing this effect and the fibrin specificity of double-bolus reteplase and front-loaded alteplase regimens are not available. In a prospective, randomized study, 50 patients with AMI were either treated with double bolus (10 + 10 U) reteplase or with front-loaded alteplase (up to 100 mg) within 6 hours of symptom onset. Thirty apparently healthy persons served as controls. Molecular markers of coagulation and fibrinolysis were serially examined for up to 5 days. Paradoxical thrombin activation at 3 hours after initiation of therapy was comparable between reteplase and alteplase. Reteplase (65 +/- 5 U/L) and alteplase (72 +/- 8 U/L) caused significantly elevated kallikrein activity at 3 hours after adminstration (p <0.01 vs controls 30 +/- 1 U/L). Fibrin specificity was less for reteplase (p <0.05) with a decrease in fibrinogen at 3 hours to 122 +/- 27 mg/dl versus 224 +/- 28 mg/dl for alteplase (p <0.01 and p <0.05 vs controls). D-Dimer levels at 3 hours were higher (p <0.05) after reteplase (5,459 +/- 611 ng/ml) versus alteplase (3,445 +/- 679 ng/ml) (both p <0.01 vs controls 243 +/- 17 ng/ml). Plasmin generation (plasmin-antiplasmin complexes) was significantly (p <0.01) increased at 3 hours with both regimens to 27,079 +/- 3,964 microg/L (reteplase) and 19,522 +/- 2,381 microg/L (alteplase). The data from 3 hours after start of thrombolytic therapy proved less marked fibrin specificity of the reteplase regimen (in vivo) compared with front-loaded alteplase. Both regimens have a moderate procoagulant effect without differences in activation of the kallikrein system.

Elevated UV-B radiation reduces genome stability in plants

Long-term depletion of the stratospheric ozone layer contributes to an increase in terrestrial solar ultraviolet-B radiation. This has deleterious effects on living organisms, such as DNA damage. When exposed to elevated ultraviolet-B radiation (UV-B; 280-315 nm), plants display a wide variety of physiological and morphological responses characterized as acclimation and adaptation. Here we show, using special sun simulators, that elevated solar UV-B doses increase the frequency of somatic homologous DNA rearrangements in Arabidopsis and tobacco plants. Increases in recombination are accompanied by a strong induction of photolyase and Rad51 gene expression. These genes are putatively involved in major DNA repair pathways, photoreactivation and recombination repair. In mutant Arabidopsis plants that are deficient in photoreactivating ultraviolet-induced cyclobutane pyrimidine dimers, recombination under elevated UV-B regimes greatly exceeds wild-type levels. Our results show that homologous recombination repair pathways might be involved in eliminating UV-B-induced DNA lesions in plants. Thus, increases in terrestrial solar UV-B radiation as forecasted for the early 21st century may affect genome stability in plants.

Responding to threat: hemispheric asymmetries and interhemispheric division of input

This investigation examined how hemispheric asymmetry and interhemispheric processing contribute to attentional biases toward emotional information. Participants (n = 88) named the color of lateralized squares presented concurrently with neutral, positive, or threatening words. A left-hemisphere advantage in color naming was reduced when distractors were emotional, suggesting right-hemisphere priming by emotional stimuli. Furthermore, the advantage of dividing the word and color across visual fields was increased for emotion words when they were frequently presented, indicating a strategic use of interhemispheric division of labor to reduce the distracting effect of emotional words. Finally, participants with high levels of anxious apprehension were most likely to make use of this interhemispheric processing strategy, supporting a processing efficiency theory of cognitive function in anxiety.

Responding to threat: hemispheric asymmetries and interhemispheric division of input

This investigation examined how hemispheric asymmetry and interhemispheric processing contribute to attentional biases toward emotional information. Participants (n = 88) named the color of lateralized squares presented concurrently with neutral, positive, or threatening words. A left-hemisphere advantage in color naming was reduced when distractors were emotional, suggesting right-hemisphere priming by emotional stimuli. Furthermore, the advantage of dividing the word and color across visual fields was increased for emotion words when they were frequently presented, indicating a strategic use of interhemispheric division of labor to reduce the distracting effect of emotional words. Finally, participants with high levels of anxious apprehension were most likely to make use of this interhemispheric processing strategy, supporting a processing efficiency theory of cognitive function in anxiety.

Neuropsychological differentiation of depression and anxiety

The high comorbidity of depression and anxiety is well established empirically but not well understood conceptually, in terms of either psychological or biological mechanisms. A neuropsychological model of regional brain activity in emotion provides contrasting hypotheses for depression and anxiety, with depression associated with a relative decrease and anxiety with a relative increase in right-posterior activity. These hypotheses received support in a comparison of individuals diagnosed with depression and community controls, and also in a separate study of nonpatients administered a measure of perceptual asymmetry. Hierarchical regressions revealed that depression and anxiety were uniquely and jointly associated with perceptual asymmetry. In light of consistent empirical support for the model, implications for conceptualizations of the comorbidity of depression and anxiety are discussed.

Contrasting patterns of brain activity in anxious apprehension and anxious arousal

Evidence suggests that a distinction between anxious apprehension (worry) and anxious arousal (somatic anxiety) might account for some discrepancies in the literature examining brain activity in anxiety. In the current study, we compared the regional brain activity of groups of anxious apprehension and anxious arousal participants, selected on the basis of self-report measures previously shown to be psychometrically distinct from each other and from a specific measure of depression. Patterns of hemispheric asymmetry in electroencephalogram alpha distinguished the two types of anxiety, with the anxious arousal group showing more right than left activity. No significant asymmetry was found for the anxious apprehension group. The results provide further support for contrasting patterns of brain activity in distinct types of anxiety. Research is needed to specify further the topography and functional significance of this distinction.

Effects of the propofol combination anesthesia on the intrinsic blood-clotting system

Fat emulsions can cause changes in blood-clotting and fibrinolysis. The aim of this study was to examine the relation between the use of the short-acting hypnotic propofol and alteration of the blood clotting system. In a double-blind randomized study, 36 patients with an aortocoronary bypass operation were given either midazolam/fentanyl or propofol/alfentanil. Eleven blood samples were taken at fixed times pre-, intra- and postoperatively to determine changes caused by the anesthetic agents on the hemostaseologic parameters during the whole operation. Perioperative blood pressures of both groups were measured at seven fixed points. From the beginning of the extracorporeal circulation (ECC) to the end of the operation, the measured values of the factor XIIa- and kallikrein-like activity in the propofol group were significantly higher than those of the midazolam group. Also the values of the kallikrein inhibition capacity and the indicators of fibrinolysis (t-PA and D-dimers) suggest a stronger activation of the contact phase at the start of the recirculation and as a result of it a stronger fibrinolysis within the propofol group. Besides, the hypotensive side-effect in the propofol group was evident in contrast to the midazolam group. With this investigation, a correlation between the application of propofol/alfentanil, contact phase activation with activation of the kallikrein-kinin-bradykinin system and the observed hypotension can be set up.

Activation markers of coagulation and fibrinolysis: alterations and predictive value in acute coronary syndromes

Several alterations of the coagulation, of the fibrinolysis and of inflammation are known in patients with acute coronary syndromes. To extent current knowledge of the pathophysiology and to optimize therapeutical strategies, the new molecular markers can be used in clinical studies. Furthermore, several studies were undertaken to assess the prognostic value of activation markers of these systems for patients with unstable angina pectoris and acute myocardial infarction with or without thrombolytic therapy. The majority of studies focussed on markers of thrombin activation, fibrinogen, fibrin degradation products and t-PA and its main inhibitor PAI-1. While there are stimulating results from larger studies, the value for prognosis for the individual patient still is limited by the overlap of patients with good versus a poor outcome.

The effects of UV exclusion on the soluble phenolics of young Scots pine seedlings in the subarctic

The characteristics of UV-absorbing compounds, particularly soluble phenolics, were studied in needles of 63-day-old seed-grown Scots pine (Pinus sylvestris L.) seedlings of two provenances in a UV exclusion field experiment at Pallas-Ounastunturi National Park in Finnish Lapland (68 degrees N, 270 m a.s.l.). The experiment used the following plastic filters in exclosure treatments to manipulate the spectral balance of natural irradiance: (1) 'control' (a polyethene plastic filter); (2) 'UV-B exclusion' (a clear polyester filter); and (3) 'UV-B/UV-A exclusion' (a clear acryl plate). Polyethene transmitted 89% of the ambient levels of total UV (280-400 nm), polyester transmitted 75% of the total UV, but only 0.6% of the UV-B (280-315 nm) component, while acryl plate transmitted 0.2% of UV (280-360 nm). The research also included (4) 'Ambient' plants that were not subjected to any treatment exclosures. After the 58 day UV exclusion, significant (p<0.0001) differences due to treatments were determined for a kaempferol derivative, kaempferol 3-glucoside, and a quercetin derivative, the quantities of which ranged from 0.23 to 0.45, 0.42 to 1.34 and 0.39 to 0.75 micromol g FW(-1), respectively, depending on treatment and provenance. Overall, Scots pine seedlings grown at ambient UV radiation (PAS300, Caldwell's generalized Plant Action Spectrum (PAS) normalized at 300 nm, 72 mW m(-2)) or under a control had significantly (p<0.05) higher quantities of soluble phenolics than seedlings grown under UV-B or UV-B/UV-A exclusion treatments. There were no significant differences in the quantity of soluble phenolics between the two exclosure treatments or between the two Scots pine provenances. The sums of diacylated flavonol glucosides ranging from 3.75 to 4.55 micromol g FW(-1) depending on treatment and provenance, were already present at very low UV-levels under the UV-B/UV-A exclusion treatment. The present study indicated that soluble phenolics, particularly the diacylated flavonol glucosides, may provide an effective preformed protection for young Scots pine seedlings against UV-B and UV-A radiation.

Evaluation of markers of deep vein thrombosis in patients undergoing surgery for maxillofacial malignancies

During and following significant surgical intervention, deep venous thrombosis prophylaxis by application of anticoagulants is routinely used. However, patients with malignant disorders are subject to an especially high risk of deep venous thrombosis progressing in severe cases to subsequent pulmonary embolism. The present study focuses on appraising modern markers of deep vein thrombosis in 34 patients undergoing major maxillofacial surgery, with some malignant disorders. No significant differences between the two patient groups were noted using the markers of the kallikrein-kinin-system. From the first postoperative day plasma levels of the coagulation indicator thrombin-antithrombin-III complexes were significantly higher in the group of tumour patients. Markers of fibrinolysis indicated corresponding results: on the first postoperative day tissue-plasminogen activator values rose to 18.9 +/- 3.2 micrograms/l in the group of malignant patients, but only to 7.4 +/- 1.1 micrograms/l (P < 0.05) in the control group. Also postoperative D-dimer concentrations in the malignancy group were significantly above those of the control group. In the present study it could be demonstrated that patients with malignant neoplasia undergoing major maxillofacial surgery are exposed postoperatively to a particularly high risk of developing thromboembolic complications. All in all, the status of anti-thrombotic therapy requires reappraisal with respect to the current treatment approach adopted in tumour patients.

Platelet protection in coronary artery surgery: benefits of heparin-coated circuits and high-dose aprotinin therapy

OBJECTIVE

To examine the extent of platelet activation during extracorporeal circulation by using the combination of heparin-coated oxygenation systems and high-dose aprotinin therapy, and to examine the affinity and thereby the protective capacity of aprotinin to the glycoprotein (GP) receptors of the platelet membrane.

DESIGN

Experimental in vitro study.

SETTING

Research laboratory of a university hospital.

PARTICIPANTS

Thirty-two volunteers (blood donors).

MEASUREMENTS AND MAIN RESULTS

Thirty-two oxygenation circuits of the same construction series (16 heparin-coated and 16 noncoated) were investigated in a closed system of a heart-lung machine model with fresh human whole blood. In each of these two groups, eight circuits with and eight without a high-dose aprotinin application (250 kallikrein inhibitory units [KIU]/mL) were investigated. In all four groups, the number of platelets declined continuously during the 90-minute recirculation period. Group I (no heparin coating, no aprotinin) showed the greatest reduction; group IV (heparin coating, aprotinin) had a significantly smaller decrease in platelet number (p < 0.01). Platelet factor 4 (PF-4) levels, released from the alpha-granule, were in inverse proportion to the platelet loss. After 90 minutes of recirculation, the PF-4 values increased to 615.8% +/- 559.5% and 237.2% +/- 179.0% of the initial value for groups I and IV, respectively (p < 0.01). Affinity chromatography and immunoblotting techniques were used to evaluate the affinity of aprotinin for the GP receptors of the platelet membrane. The affinity appeared in the following order: GPIIb < GPIIIa < GPIb.

CONCLUSION

Heparin-coated oxygenation systems and additional aprotinin caused significantly less platelet damage in an in vitro cardiopulmonary bypass model. Chromatographic and immunologic methods could prove aprotinin's affinity for the platelet receptor proteins GPIb and GPIIb-IIIa and therefore its probable role in diminishing the triggering of the platelet activation cascade.

[Blood coagulation and fibrinolysis in arteriosclerosis]

Thrombus formation at the site of atherosclerotic lesions, especially on a ruptured plaque, plays a central role in the "atherothrombosis" hypothesis. An activation of the hemostasis and a disturbed fibrinolysis are known. These alterations are especially marked in patients with acute coronary syndromes. In stable coronary artery disease, fibrinogen is elevated. Furthermore, minor alterations of the contact phase factor VII and consecutively of the thrombin system are detectable depending on the study population. Thrombin generation and activation become marked in patients with unstable angina pectoris or acute myocardial infarction. Possible reasons for this activation are an activation of the contact phase factor XII system and the release of tissue factor both from the ruptured plaque and from stimulated monocytes. The fibrinolytic system is markedly altered already in patients with stable coronary heart disease. Increased levels of tissue-type plasminogen activator and of urokinase-type plasminogen activator/receptor are measurable in atheromas. Tissue-type plasminogen activator mass concentration is systemically elevated already at early stages of atherosclerosis. Especially in patients with increased risk for acute coronary syndromes, the plasminogen activator inhibitor activity is significantly increased. Furthermore, a hypercoagulative state with increased d-dimer levels and plasmin-antiplasmin complexes can be measured. The alterations of hemostasis and especially of fibrinolysis are detectable for prolonged time period and persist much longer than the clinical symptoms of the patients. The increased plasminogen activator inhibitor activity is associated with the metabolic syndrome and constitutes an (in part genetically determined) disturbance in patients with stable or unstable coronary heart disease. However, the large intra- und interobserver as well as diurnal variability of this marker limits its use as a routine measure for risk stratification in patients. Alterations of the hemostasis and disturbances of fibrinolysis are detectable during the chronic as well as the acute phase of atherosclerosis. These changes are best documented for coronary heart disease, whereas less data are available for other manifestations of atherosclerosis. The use of newly developed molecular markers for single reaction steps of pathways instead of global functional tests and of new molecular biological methods did considerably improve the detailed knowledge on the pathomechanisms of the development of atherosclerosis, making the development of targeted therapies, e.g., against receptors possible. Future studies will investigate the quantitative impact of the various activated pathways (cause or reaction) and the effects of interventions on these pathomechanisms in patients with acute coronary syndromes. Studies will have to focus especially on the meaning of polymorphisms, early changes in the development of atherosclerosis and interactions with inflammatory processes.

Correlation between coronary morphology and molecular markers of fibrinolysis in unstable angina pectoris

BACKGROUND

In acute coronary syndromes, marked alterations of coagulation and fibrinolysis have been observed, but no data are available concerning a possible relation to coronary stenosis morphology.

METHODS

Thirty one patients with unstable angina pectoris were included. Culprit stenosis morphology judged from coronary angiography was graded using the modified ACC/AHA classification. Molecular and functional markers of hemostasis and fibrinolysis were determined from venous plasma samples obtained at admission.

RESULTS

Patients with unstable angina pectoris had a moderate procoagulant state, especially a contact phase activation compared with age-matched controls (factor XII 93.9 +/- 5.6 vs 112.8 +/- 5.4%; P < 0.05; high molecular weight kininogen 55.3 +/- 5.4 vs 86.1 +/- 6.5%; P < 0.01). Thrombin-antithrombin (TAT) was not significantly elevated (7.6 +/- 1.9 vs 4.0 +/- 0.5 microg/l). Elevated plasminogen activator mass concentration (16.6 +/- 2.1 vs 5.4 +/- 0.6 ng/ml; P < 0.01) and plasminogen activator inhibitor (PAI) activity (9.9 +/- 3.0 vs 5.6 +/- 3.0 AU/ml; P < 0.05) indicated an alteration of the fibrinolysis. Complexity of coronary stenosis was positively correlated with tissue-type plasminogen activator (TPA) mass concentration (P < 0.01) and PAI activity (P < 0.05). No association was found to markers of a hypercoagulative state.

CONCLUSION

These findings indicate a relation between alterations of the fibrinolytic system and coronary morphology, whereas the acute changes of coagulation occur independently of culprit stenosis complexity.

Action of aprotinin in myocardial ischemia - an investigation using a plasma-free model

BACKGROUND

The protease inhibitor aprotinin has been reported to have an anti-ischemic effect on left-ventricular myocardium in patients undergoing cardiopulmonary bypass operation. To examine the anti-ischemic properties beside its antifibrinolytic and inhibitory action on the kallikrein-bradykinin system, we investigated this substance in buffer-perfused rat hearts.

METHODS

24 isolated isovolumically contracting rat hearts received a 10-minute infusion of either 10000 units aprotinin or pure saline followed by 30 minutes of no-flow global ischemia and 45 minutes of reperfusion. Hemodynamics, high-energy phosphates, and troponin T as molecular marker of cardiac injury were studied.

RESULTS

During 15 minutes of reperfusion steady state function was identical in both groups, with a recovery of the developed left-ventricular pressure to 81.9+/-1.5% after protease inhibition and 83.0+/-2.6% in the controls. Coronary flow, myocardial oxygen consumption, and contractile reserve after maximum Ca++ stimulation were also identical. High-energy phosphates were comparably reduced in both groups (adenine nucleotides: 3.1+/-0.3 micromol/g ww after aprotinin vs. controls 2.7+/-0.4 micromol/g ww and creatine phosphate: 6.5+/-0.9 micromol/g ww vs. controls 4.7+/-1.1 micromol/g ww). However, release of the cardiac specific marker troponin T was lower after ischemia at several measurements (p<0.05). The total release of troponin T was 44+/-10 ng in the aprotinin treated hearts vs. 90+/-17 ng in the postischemic control hearts (p<0.05).

CONCLUSIONS

The findings demonstrate that aprotinin in a moderate dose is effective in reducing postischemic troponin release in a non-blood perfused system. Measurement of myocardial high-energy phosphates after aprotinin use was performed for the first time and indicates that not a reduction in severity of direct myocardial ischemic intensity but a beneficial action on processes causing release of troponin is the mode of action of this effect.

Expression of uroporphyrinogen decarboxylase or coproporphyrinogen oxidase antisense RNA in tobacco induces pathogen defense responses conferring increased resistance to tobacco mosaic virus

Transgenic tobacco plants with reduced activity of either uroporphyrinogen decarboxylase or coproporphyrinogen oxidase, two enzymes of the tetrapyrrole biosynthetic pathway, are characterized by the accumulation of photosensitizing tetrapyrrole intermediates, antioxidative responses, and necrotic leaf lesions. In this study we report on cellular responses in uroporphyrinogen decarboxylase and coproporphyrinogen oxidase antisense plants, normally associated with pathogen defense. These plants accumulate the highly fluorescent coumarin scopolin in their leaves. They also display increased pathogenesis-related protein expression and higher levels of free and conjugated salicylic acid. Upon tobacco mosaic virus inoculation, the plants with leaf lesions and high levels of PR-1 mRNA expression show reduced accumulation of virus RNA relative to wild-type controls. This result is indicative of an increased resistance to tobacco mosaic virus. We conclude that porphyrinogenesis as a result of deregulated tetrapyrrole synthesis induces a set of defense responses that resemble the hypersensitive reaction observed after pathogen attack.

Thrombolytic therapy in acute myocardial infarction: comparison of procoagulant effects of streptokinase and alteplase regimens with focus on the kallikrein system and plasmin

BACKGROUND

Thrombolytic therapy in patients with acute myocardial infarction (AMI) is hampered by procoagulant effects. In vitro studies have indicated that plasmin stimulation activates the kallikrein-contact-phase system, resulting in thrombin activation. This prospective comparative study was designed to examine the procoagulant effects of streptokinase or alteplase in AMI.

METHODS AND RESULTS

Sixty-one patients with AMI received 1.5 million U of streptokinase or front-loaded alteplase (up to 100 mg) and systemic heparin. Twenty-four patients with AMI and no thrombolytic therapy and 30 control subjects were examined for comparison. Molecular markers of thrombin, plasmin activation, and coagulation activities were determined before therapy and serially for up to 10 days. Moderate thrombin (initial thrombin-antithrombin [TAT] complex 18+/-5 versus 4+/-0.3 microg/L, P<0.05) and kallikrein (up to 45+/-4 versus 30+/-1 U/L at 3 hours, P<0.01) activation occurs in patients with AMI. D-Dimers are increased (P<0.01), and plasmin is stimulated (P<0.01). Streptokinase and alteplase increase TAT to 50+/-17 and 51+/-18 microg/L at 3 hours and to 50+/-17 and 33+/-14 microg/L at 6 hours, respectively (P<0.01). Kallikrein activity is elevated (P<0. 01) to 76+/-5 and 71+/-7 U/L at 3 hours and 64+/-6 and 47+/-5 U/L by streptokinase and alteplase, respectively, at 6 hours. Reductions in fibrinogen and increases in D-dimers and plasmin-antiplasmin complexes are more marked (P<0.05 and 0.01) after streptokinase versus alteplase. Correlations were found among TAT, kallikrein activity, and plasmin activation (P<0.01).

CONCLUSIONS

The data indicate a more marked procoagulant action of the streptokinase regimen compared with front-loaded alteplase, thus supporting the hypothesis of a plasmin-mediated kallikrein activation with consecutive procoagulant action in vivo.