Open Science in regulatory environmental risk assessment.

A possible way to alleviate the public skepticism toward regulatory science is to increase transparency by making all data and value judgments used in regulatory decision making accessible for public interpretation, ideally early on in the process, and following the concepts of Open Science. This paper discusses the opportunities and challenges in strengthening Open Science initiatives in regulatory environmental risk assessment (ERA). In this discussion paper, we argue that the benefits associated with Open Science in regulatory ERA far outweigh its perceived risks. All stakeholders involved in regulatory ERA (e.g., governmental regulatory authorities, private sector, academia, and nongovernmental organizations), as well as professional organizations like the Society of Environmental Toxicology and Chemistry, can play a key role in supporting the Open Science initiative, by promoting the use of recommended reporting criteria for reliability and relevance of data and tools used in ERA, and by developing a communication strategy for both professionals and nonprofessionals to transparently explain the socioeconomic value judgments and scientific principles underlying regulatory ERA. Integr Environ Assess Manag 2021;17:1229-1242. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Population-level effects and recovery of aquatic invertebrates after multiple applications of an insecticide.

Standard risk assessment of plant protection products (PPP) combines "worst-case" exposure scenarios with effect thresholds using assessment (safety) factors to account for uncertainties. If needed, risks can be addressed applying more realistic conditions at higher tiers, which refine exposure and/or effect assessments using additional data. However, it is not possible to investigate the wide range of potential scenarios experimentally. In contrast, ecotoxicological mechanistic effect models do allow for addressing a multitude of scenarios. Furthermore, they may aid the interpretation of experiments such as mesocosm studies, allowing extrapolation to conditions not covered in experiments. Here, we explore how to use mechanistic effect models in the aquatic risk assessment of a model insecticide (Modelmethrin), applied several times per season but rapidly dissipating between applications. The case study focuses on potential effects on aquatic arthropods, the most sensitive group for this substance. The models provide information on the impact of a number of short exposure pulses on sensitive and/or vulnerable populations and, when impacted, assess recovery. The species to model were selected based on their sensitivity in laboratory and field (mesocosm) studies. The general unified threshold model for survival (GUTS) model, which describes the toxicokinetics and toxicodynamics of chemicals in individuals, was linked to 3 individual-based models (IBM), translating individual survival of sensitive organisms into population-level effects. The impact of pulsed insecticide exposures on populations were modeled using the spatially explicit IBM metapopulation model for assessing spatial and temporal effects of pesticides (MASTEP) for Gammarus pulex, the Chaoborus IBM for populations of Chaoborus crystallinus, and the "IdamP" model for populations of Daphnia magna. The different models were able to predict the potential effects of Modelmethrin applications to key arthropod species inhabiting different aquatic ecosystems; the most sensitive species were significantly impacted unless respective mitigation measures were implemented (buffer zones resulting in reduced exposure). As expected the impact was stronger in shallow ditches as compared to deeper pond scenarios. Furthermore, as expected, recovery depended on factors such as temperature (affecting population growth rate and number of generations) and the occurence of nonimpacted aquatic ecosystems (their frequency and connectivity). These model predictions were largely in line with field observations and/or the results of a mesocosm study, providing additional evidence on the suitability and reliability of the models for risk assessment purposes. Because of their flexibility, models may predict the likelihood of unacceptable effects-based on previously defined protection goals-for a range of insecticide exposure scenarios and freshwater habitats.

Inflammatory response in transapical transaortic valve replacement.

OBJECTIVE: Transapical aortic valve implantation (TA-AVI) has become a fast growing alternative to conventional aortic valve replacement (cAVR) particularly for patients burdened with serious comorbidities. We investigated whether the inflammatory response triggered by TA-AVI reflects the less invasive nature of this procedure. METHOD: In this prospective observational study 25 patients undergoing aortic valve replacement (AVR; 15 cAVR and 10 TA-AVI) were included. Serial plasma cytokine concentrations (IL-6, IL-8, and IL-10) were measured by commercially available enzyme-linked immunosorbent assay kits at six different time points before, during, and after surgery. RESULTS: Plasma levels of all three cytokines increased during and after both procedures and returned to baseline before the patient's discharge. Peak values of IL-6 were 258 ± 113 pg/mL in AVR patients versus 111 ± 101 pg/mL in TA-AVI patients and were reached 12 hours after surgery. For IL-8, peak values were 51 ± 29 pg/mL 1 hour after surgery in AVR patients versus 15 ± 20 pg/mL on wound closure in TA-AVI patients. Plasma levels of IL-6 and IL-8 were significantly reduced in the TA-AVI group as compared with cAVR. IL-10 is markedly activated in both groups yet its induction is more prominent in AVR patients with peak values of 51 ± 28 pg/mL for AVR versus 24 ± 18 pg/mL for TA-AVI on wound closure. CONCLUSION: TA-AVI compared with cAVR results in a significant reduction but not elimination of a systemic inflammatory response, which is attributable to cardiopulmonary bypass-dependent and bypass-independent factors.

Influence of aortic dimensions on the hemodynamic performance of small aortic valve prostheses: impact on patient/prosthesis mismatch.

BACKGROUND: Since Doppler echocardiography takes no account of pressure recovery, the true hemodynamic burden of aortic valve prostheses remains vague. The purpose of this study was to elucidate the methodological error of Doppler gradient estimation by means of a model demonstrating the different influence of aortic root diameters on net and Doppler gradients, respectively. This matters especially in small valves and the related patient/prosthesis mismatch calculation. METHODS: Two bileaflet small aortic valve prostheses (19 mm SJM Regent® and On-X® valve) were tested using a pulsatile circulatory mock loop simulator with two different aortic models: one with statistically normal diameters according to annular size, another one simulating an aortic aneurysm of 50 mm. Doppler and simultaneously recorded net gradients as well as systolic energy losses were obtained for different hemodynamic conditions. RESULTS: In all measurements a significant amount of pressure recovery was observed. In cases of aortic aneurysm systolic energy loss increased significantly for each cardiac output at each heart rate ( P < 0.0028), reflected by a significant ( P < 0.0001) increase in net gradients. The corresponding Doppler gradients were unchanged. This indicates significantly less pressure recovery ( P < 0.0001) in the aneurysmatic aorta. CONCLUSIONS: Geometry of the ascending aorta considerably alters aortic valve hemodynamic parameters. The hemodynamic function of small aortic valve prostheses, especially with corresponding normal outflow dimensions, is much better than expected from Doppler gradients. Thus, calculation of a patient/prosthesis mismatch can be misleading.

Impact of pressure recovery in the evaluation of the Omnicarbon tilting disc valve.

BACKGROUND: Pressure recovery is not taken into account when calculating trans-prosthetic gradients after mechanical valve replacement using Doppler echocardiography. This may lead to underestimation of valvular performance. METHODS: Simultaneous measurement of Doppler and direct trans-prosthetic gradients was performed in a circulatory mock loop simulator with physiologic parameters at different heart rates and cardiac outputs for small-sized aortic Omnicarbon tilting disc valves (19 - 21 mm). RESULTS: In all adjustments the Doppler gradient significantly overestimated the net transvalvular gradient. The amount of pressure recovery averaged 59.3 %. CONCLUSIONS: Doppler echocardiography does not allow for pressure recovery, which is a significant phenomenon in the hemodynamic function of the Omnicarbon tilting disc valve. Valve performance is much better than expected from Doppler gradients.

Aquatic risk assessment of the new rice herbicide profoxydim.

A tiered protocol for assessing ecological risks has been applied to the rice pesticide profoxydim. The initial assessment (Tier I) was based on toxicity exposure ratio (TER) calculations based on laboratory data using a worst-case rice scenario. The first refinement (Tier II) was based on direct toxicity assessment (DTA) of water samples collected during a field-mesocosm study. Finally, a higher-tier assessment on the in situ assessment of paddy community responses (field-mesocosm-Tier III) was performed. A successive application of three pesticides, the herbicides azimsulfuron, propanil and the insecticide malathion, was used as reference controls. The refined assessments indicated a lower risk than that predicted from TER estimations. DTA-based Tier II showed toxicity effects only for concentrations above the recommended dose of profoxydim. Effects for reference controls were observed in DTA which were not expected from Tier I. The field-mesocosm study confirmed these effects but also showed that they were transient and of low relevance.

Value of echocardiography in patient follow-up after surgically corrected type A aortic dissection.

BACKGROUND: To identify patients (pts) at risk of late complications, follow-up after surgery for type A aortic dissection is essential. We assessed the value of echocardiography to monitor patients after surgery for type A aortic dissection. METHODS: 80 out of 108 pts operated between 1989 and 1999 for type A aortic dissection survived surgery. 62 pts with at least one TEE, CT or MRI examinations during follow-up were included in this study. All pts had transthoracic echocardiography (TTE), 53 transesophageal echocardiography (TEE), 51 had CT, and 39 had MRI. RESULTS: At the first follow-up, 12 of 48 pts with aortic valve sparing surgery presented with aortic insufficiency >I degrees detected using echocardiography. 16 pts evolved a distal aortic aneurysm of over 5 cm, all seen in TEE, CT and MRI. A distal intimal flap was present in 39 pts and could be seen in TEE, CT and MRI in all patients. A new proximal aortic root dissection took place in 5 pts. Progressive aortic pathology led to reoperation in 9 pts. TEE was especially useful in 2 pts to confirm redissection, in 1 pt to rule out redissection assumed by CT, and in 1 with paraprosthetic blood flow after ascending aortic replacement. MRI led to additional information in 1 patient with false aneurysm of the distal anastomosis and 1 with redissection not seen in TEE 6 month before. CT and MRI were superior to TEE in demonstrating aortic arch pathology, whereas TEE was more effective in showing the flow pattern and residual entry sites. CONCLUSIONS: Echocardiography is an effective and cost-saving diagnostic tool to monitor pts after surgery for type A aortic dissection, and should be the method of choice to ascertain aortic pathology initially after surgery. Follow-up intervals and need for additional CT or MRI should be determined afterwards according to specific pathologies.

Aortic valve preservation in acute type A dissection: mid-term results.

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the long-term effectiveness of a strategy for managing the aortic valve, aortic root and ascending aorta according to the pathology in acute aortic type A dissection. Results after surgery for acute type A dissection with preservation of the aortic valve were reviewed. METHODS: The patient group included 57 hospital survivors operated on according to a surgical strategy of aortic valve resuspension and supracoronary ascending aortic graft implantation. Reinforcement of the aortic stumps with gelatin-resorcinol-formaldehyde glue was performed in all patients. Aortic valve function in all survivors was investigated by echocardiographic follow up at 30 days, 6 and 12 months after surgery, and yearly thereafter. RESULTS: During the follow up period, nine patients (16%) died without reoperation. Actuarial probability of freedom from reoperation for aortic valve failure in the complete series was estimated as 100% after both 30 days and 12 months. Postoperatively, one patient underwent reoperation 14 months for aortic regurgitation, and three patients for aortic regurgitation with sinus of Valsalva dilatation between 48 and 88 months. The hospital mortality rate at reoperation was 50% (n = 2). CONCLUSION: Valve-sparing surgery is possible and can be recommended for the majority of patients with acute type A aortic dissection.

Coronary artery bypass grafting in adult coronary artery disease due to suspected Kawasaki disease in childhood.

Development of coronary artery aneurysms is one typical complication of Kawasaki disease and can cause coronary artery disease even in early childhood. Information about course and outcome in adults is rare. Here, we present a 49-year-old man with serious three-vessel coronary artery disease and giant coronary artery aneurysms following suspected Kawasaki disease.

Decalcification of the aortic valve does not prevent early recalcification.

BACKGROUND AND AIM OF THE STUDY: The excellent results with atrioventricular valve reconstruction have stimulated surgeons to attempt reconstruction of calcified aortic valves using decalcifying techniques, but long-term results have been disappointing. The aim of this in vitro study was to evaluate the surface structure of decalcified aortic valve tissue and its potential for recalcification. METHODS: Aortic leaflets were removed from 26 patients with aortic stenosis during elective valve replacement and decalcified by meticulous dissection. Representative specimens were prepared for scanning electron microscopy (SEM) and calcium content in the heavily calcified part of the leaflet in both macroscopically non-calcified and decalcified tissue was determined by atomic absorption spectroscopy (AAS). Additional probes of 'non-calcified' and decalcified tissue were incubated for two and four weeks with medium containing a physiological concentration of calcium to determine their potential for recalcification. As a control, 13 specimens from non-calcified valves were incubated according to the same protocol. RESULTS: All calcified specimens contained high calcium levels (142.70+/-53.76 mg/g). Surgical dissection reduced tissue calcium content significantly (10.04+/-13.43 mg/g). Following two weeks' incubation with calcium, these specimens retained significantly higher levels of calcium (2.88+/-5.17 mg/g) than the 'non-calcified' specimens (19.17+/-7.61 versus 13.49+/-6.27 mg/g; p<0.05); after four weeks similar calcium levels were reached (32.00+/-10.27 versus 28.35+/-9.84 mg/g; p = NS). Non-calcified tissue showed the lowest calcium uptake (4.75+/-4.55 mg/g and 12.29+/-9.43 mg/g at two and four weeks; p<0.05). SEM revealed a loss of endothelial coverage in the calcified areas; decalcification led to an irregular fibrillar surface. Only parts of the macroscopically normal tissue contained endothelial cells, whereas the control tissue showed intact cellular coverage. CONCLUSION: Aortic valve decalcification can effectively remove calcifications, but leaves a fibrillar structure that tends rapidly to accumulate calcium. Even normal-appearing tissue from diseased valves has a higher potential for calcification than normal valvular tissue. These data support the observation of only limited clinical benefits being derived after aortic valve decalcification for aortic stenosis.

Determinants of calcium uptake of bovine pericardium for heart valve replacement: results of in vitro studies.

BACKGROUND AND AIMS OF THE STUDY: Reduction of biomaterial calcification is an important aim in the basic research of biological heart valves. An in vitro model was used to investigate the influence of serum calcium concentration and surface coverage with cells or basal proteins on calcium uptake of bovine pericardium. METHODS: Samples of glutaraldehyde-tanned bovine pericardium, stored in formaldehyde and detoxified with borohydride were incubated for two weeks with cell culture medium containing low (1.0 mmol/l) or physiologic (2.3 mmol Ca/l) calcium concentration. Specimens were either unseeded, completely surface-covered with rat fibrocytes (rf) or fibrin (fi), or incompletely seeded with rabbit cells (re). Quality of surface coverage was assessed by surface scanning electron microscopy and calcium content by atomic absorption spectroscopy. RESULTS: Serum calcium had a significant influence on calcium uptake (low versus physiological (1.58 +/- 2.45 mg/g versus 8.10 +/- 1.73 mg/g wet wt, p < 0.001). This may explain early calcification of bioimplants in children and patients on dialysis. Surface coverage significantly reduces calcium uptake (fi, 1.20 +/- 0.41 mg/g, rf, 4.20 +/- 1.70 mg/g, p < 0.001) but complete coverage is necessary (re, 6.98 +/- 1.64 mg/g, NS). CONCLUSIONS: In vitro testing of calcium uptake has proven to be a valuable tool for evaluation of biomaterial calcification.

Pathophysiology of early failure of autologous aortic heart valves (ATCV).

BACKGROUND: Degeneration remains the major drawback of bioprostheses. Among various concepts to mitigate degeneration, the use of autologous pericardium for intraoperative construction of aortic valves (ATCV) was revived recently. Based on in-vivo studies the problem of tissue failure was claimed to be oversome by short immersion in glutaraldehyde. METHODS: Two often ATCV implanted 1994-1996 had to be replaced because of valvular insufficiency due to leaflet shrinkage or tearing. Pathophysiology of failure was evaluated by light microscopy and immune histology, scanning electron microscopy (SEM) and determination of tissue calcium content (AAS). RESULTS: AAS revealed high calcium levels in the shrunken and low levels in the torn leaflets. Histology demonstrated extensive fiber degeneration without inflammation in the destructed and moderate degeneration in the intact leaflets. SEM showed smooth surfaces in the 'normal' and exposure of collagen in the degenerated leaflet associated with calcification. Tears occurred close to the stents. CONCLUSIONS: Failure of ATCV is characterised by either shrinkage and calcification despite a short tanning or by tearing related to the stent design. Clinical use of ATCV cannot be recommended at present.

Quantification of mitral valve stenosis by three-dimensional transesophageal echocardiography.

The aim of this study was the evaluation of the diagnostic potentials of transesophageal 3D- echocardiography in the determination of mitral valve stenosis. 54 patients were investigated by transthoracic and multiplane transesophageal echocardiography. In 41 patients cardiac catheterization was performed. 3D- echocardiographic data acquisition was performed by automatic transducer rotation at 2 degree increments over a span of 180 degrees. The transesophageal probe was linked to an ultrasound unit and to a 3D- workstation capable of ECG- and respiration gated data acquisition, postprocessing and 2D/3D image reconstruction. The mitral valve was visualized in sequential cross-sectional planes out of the 3D data set. The spatial position of the planes was indicated in a reference image. In the cross-sectional plane with the narrowest part of the leaflets the orifice area was measured by planimetry. For topographic information a 3D view down from the top of the left atrium was reconstructed. Measurements were compared to conventional transthoracic planimetry, to Doppler-echocardiographic pressure half time and to invasive data. The mean difference to transthoracic planimetry, pressure half time and to invasive measurements were 0.3 +/- 0.1 cm2, 0.2 +/- 0.1 cm2 and 0.1 +/- 0.1 cm2, respectively. Remarkable differences between the 3D- echocardiographic and the 2D- or Doppler- echocardiographic methods were observed in patients with severe calcification or aortic regurgitation. In 22% of the patients the 3D data set was not of diagnostic quality. New diagnostic information from a 3D view of the mitral valve could be obtained in 69% of the patients. Thus, although image quality is limited, 3D- echocardiography provides new topographic information in mitral valve stenosis. It allows the use of a new quantitative method, by which image plane positioning errors and flow-dependent calculation is avoided.

A DNA-polymerase-related reading frame (pol-r) in the mtDNA of Secale cereale.

Mitochondrial (mt)DNA of Secale cereale contains an open reading frame (pol-r), the potential translation product of which shows significant homology to the type-B DNA polymerase encoded by the S1 plasmid of Zea mays; it contains the highly-conserved domains IIa to V of family B polymerases. The pol-r ORF is transcribed, as proven by RT-PCR, but the transcript is not edited. Upstream of the putative start codon a potential promoter motif was detected, fitting well into the postulated consensus sequence of the transcription initiation regions of Z. mays and Triticum aestivum. The pol-r ORF occurs in mtDNA of the fertile rye variety "Halo" and the cytoplasmic male-sterile (CMS) line "Pampa". Both ORFs are almost identical, apart from the 3' terminus; pol-r from Halo can code for 289 amino acids, pol-r from Pampa for 312 amino acids. Based on codon usage and the lack of editing, pol-r is considered to be a "young" gene, probably introduced in the mtDNA of rye by recombination with an mt plasmid.

CMS in rye: comparative RFLP and transcript analyses of mitochondria from fertile and male-sterile plants.

The mitochondrial (mt) genomes of rye (Secale cereale L.) lines with "normal" and cytoplasmic male sterility (CMS) inducing "Pampa" cytoplasm were compared by detailed restriction fragment length polymorphism (RFLP) and Northern analyses. RFLP analyses using several heterologous mt genes as probes revealed considerable differences in the overall structure of the two mt genomes. With cob and atpA, the data indicate intragenic recombination and/or different copy numbers of these genes in the two cytoplasms. In spite of this heterogeneity at DNA level, the transcriptional patterns of nine out of ten mitochondrial genes analysed are unaffected. The exception is in the "Pampa" cytoplasm which contains an additional cob-homologous transcript. Since this transcript is strongly reduced in the presence of restorer genes, it might causally be correlated to the CMS phenotype.

Transthoracic and transesophageal echocardiography to diagnose ventricular septal rupture: importance of right heart infarction.

BACKGROUND: Rapid and accurate diagnosis of ventricular septal rupture (VSR) remains difficult, and the monitoring of hemodynamic deterioration is a prerequisite for the institution of adequate therapy. The timing of surgical repair is a matter of controversy. METHODS: Transthoracic, transesophageal, color Doppler, and contrast echocardiography were evaluated in 17 patients with VSR in whom the diagnosis was confirmed by catheterization, surgery, or necropsy. RESULTS: Routine transthoracic echocardiography visualized VSR in four out of 17 patients and, with additional views, in 12 out of 17 patients. Color Doppler echocardiography identified the rupture in 15 out of 16, and contrast echocardiography in 11 out of 11 patients. VSR was identified using transesophageal echocardiography in six out of nine patients, and using color Doppler and contrast echocardiography in all patients. Eight out of 10 patients who developed right heart myocardial infarction (RMI) died, whereas all patients without RMI survived (P = 0.0070). Similarly, eight out of 10 patients with shock died, whereas all patients without survived (P = 0.0070). Shock occurred more often in patients with RMI (eight out of 10) than in patients without (two out of six). All patients with both RMI and shock died, whereas those without both conditions survived (P = 0.0002). CONCLUSION: Modern echocardiography is the method of choice in the diagnosis of VSR. Right ventricular function should be evaluated in patients with VSR because patients with RMI are at high risk of hemodynamic deterioration, with poor outcome. RMI, visible as abnormal wall motion, was identified better with transesophageal than with transthoracic echocardiography.

Diagnosis of papillary muscle rupture after acute myocardial infarction by transthoracic and transesophageal echocardiography.

The sensitivity of transthoracic echocardiography to visualize the structural abnormality of papillary muscle rupture (PMR) after acute myocardial infarction can be anticipated to average about 50%; therefore, we evaluated five patients exhibiting the condition with both transthoracic and transesophageal echocardiography. The use of the two imaging techniques resulted in the fact that no instance of PMR was missed. Using transthoracic echocardiography in two patients and transesophageal echocardiography in four, the ruptured papillary muscle was visualized directly. Mitral insufficiency as an indirect sign was observed in all patients. In one patient the papillary muscle rupture developed in a mitral valve previously affected by endocarditis. All patients underwent mitral valve replacement and coronary artery bypass grafting. The diagnosis was confirmed at surgery in all patients. Four patients died in hospital, the fifth 5 months later. We recommended that transesophageal echocardiography be performed in patients with suspected PMR if transthoracic echocardiography does not provide an unequivocal diagnosis.

Biochemical response of Norway spruce (Picea abies (L.) Karst.) towards 14-month exposure to ozone and acid mist: effects on amino acid, glutathione and polyamine titers.

Two clones of Norway spruce were exposed to elevated ozone levels (100 microg m(-3) with episodes of 130-360 microg m(-3)) in combination with acidic mist (pH 3.0) for two vegetation periods. The plants did not exhibit any visible injury, but levels of several amino acids and polyamines were altered in comparison with control plants (50 microg m(-3) ozone, mist of pH 5.6), the changes being pronounced in clone 14. Total free amino acids as well as methionine titers were increased in clone 14. Asparagine was significantly increased in clone 11 and less so in clone 14. Arginine, which comprised more than 50% of the free amino acids in spruce needles, was not changed by the exposure regime applied. Reduced glutathione was significantly increased in all clones/soil/needle age combinations (average increase 50%). Free soluble putrescine was enhanced by 50-200% in clone 14, but remained unchanged in clone 11. Conjugated putrescine was significantly, and conjugated spermidime was slightly, increased in both clones, whereas other polyamines did not responde to the treatment.

Indirect effects of air pollutants: Changes in plant/parasite interactions.

The impact of air pollutants on plant/parasite-interactions has been investigated. It could be demonstrated that fumigation of Vicia faba L. with 0.15 ppm SO2 (400 microg m(-3)) or 0.2 ppm NO2 (400 microg m(-3)) during 7 days caused changes in plant metabolism which resulted in higher growth rates of the aphid Aphis fabae Scop. feeding on these plants. Fumigation of V. faba with 0.085 ppm O3 during 2 or 3 days, however, caused decreased aphid growth on fumigated plants. That result could be reversed by higher O3 concentrations or through the presence of NOx during O3 fumigation. Ambient air comprising a mixture of pollutant gases had a strong enhancing effect on aphid performance. Thus, the growth of A. fabae on field bean plants was significantly higher in ambient summertime. London air than in charcoal-filtered air. Similarly, the growth of Macrosiphon rosae L. on rose bushes (Rosa sp., cv. Nina Weibull) was improved in ambient summertime Munich air; the increase in growth rate averaged about 20%.

Secondary effects of air pollution: ozone decreases brown rust disease potential in wheat.

Young wheat plants were fumigated with 170 microg m(-3) ozone for 3 days, or with 210 microg m(-3) ozone for 7 days, for 7 hours a day. At the end of the fumigation period the plants were inoculated with brown rust (Puccinia recondita f. sp. tritici) uredospores. The development of new uredospore pustules on fumigated and control plants was evaluated as a measure of rust disease potential. The number of pustules on the ozone fumigated plants was greatly reduced in comparison with the number of plants treated with charcoal-filtered air.