Home nursing and self-administered outpatient parenteral antimicrobial treatment: a comparison of demographics and outcomes from a large regional hospital in Queensland, Australia.

BACKGROUND: Outpatient parenteral antimicrobial treatment (OPAT) is a safe and effective therapy used in several settings across Australia. As OPAT services expand their inclusion criteria to include complex patient populations, there is an increased need for selecting appropriate patients to receive either healthcare-administered OPAT (H-OPAT) or self-administered OPAT (S-OPAT). AIMS: To describe patient demographics, diagnosis, microbiology and outcomes of patients treated by H-OPAT and S-OPAT within the Sunshine Coast Hospital and Health Service, Australia. METHODS: Data on demographics, diagnoses, treatment and outcomes on all patients treated by H-OPAT and S-OPAT from March 2017 to December 2019 were collected retrospectively. RESULTS: One hundred and sixty-five patients (62.26%) were enrolled in H-OPAT and 100 patients (37.74%) in S-OPAT. S-OPAT patients were significantly younger. H-OPAT patients were more comorbid. Bone and joint infections were the most treated infections and were more likely to be treated by S-OPAT. There was no difference in treatment duration, cure and complication rates between S-OPAT and H-OPAT. Longer duration of therapy was associated with more complications. Treatment failure was associated with infections due to multiple organisms, number of comorbidities and treatment of surgical site, skin and soft tissue infections. CONCLUSIONS: There were significant differences in demographics between H-OPAT and S-OPAT without any difference in outcomes. Overall failure and complication rates were low. Higher rates of treatment failure were predicted by the diagnosis, number of comorbidities and number of organisms treated.

Participant characteristics and reasons for non-consent to health information linkage for research: experiences from the ATHENA COVID-19 study.

BACKGROUND: The linkage of primary care, hospital and other health registry data is a global goal, and a consent-based approach is often used. Understanding the attitudes of why participants take part is important, yet little is known about reasons for non-participation. The ATHENA COVID-19 feasibility study investigated: 1) health outcomes of people diagnosed with COVID-19 in Queensland, Australia through primary care health data linkage using consent, and 2) created a cohort of patients willing to be re-contacted in future to participate in clinical trials. This report describes the characteristics of participants declining to participate and reasons for non-consent. METHODS: Patients diagnosed with COVID-19 from January 1st, 2020, to December 31st, 2020, were invited to consent to having their primary healthcare data extracted from their GP into a Queensland Health database and linked to other data sets for ethically approved research. Patients were also asked to consent to future recontact for participation in clinical trials. Outcome measures were proportions of patients consenting to data extraction, permission to recontact, and reason for consent decline. RESULTS: Nine hundred and ninety-five participants were approached and 842(85%) reached a consent decision. 581(69%), 615(73%) and 629(75%) consented to data extraction, recontact, or both, respectively. Mean (range) age of consenters and non-consenters were 50.6(22-77) and 46.1(22-77) years, respectively. Adjusting for age, gender and remoteness, older participants were more likely to consent than younger (aOR 1.02, 95%CI 1.01 to 1.03). The least socio-economically disadvantaged were more likely to consent than the most disadvantaged (aOR 2.20, 95% 1.33 to 3.64). There was no difference in consent proportions regarding gender or living in more remote regions. The main reasons for non-consent were 'not interested in research' (37%), 'concerns about privacy' (15%), 'not registered with a GP' (8%) and 'too busy/no time' (7%). 'No reason' was given in 20%. CONCLUSION: Younger participants and the more socio-economically deprived are more likely to non-consent to primary care data linkage. Lack of patient interest in research, time required to participate and privacy concerns, were the most common reasons cited for non-consent. Future health care data linkage studies addressing these issues may prove helpful.

Evaluating the magnet response in deep subcutaneous implanted cardioverter defibrillator implants.

INTRODUCTION: The manufacturer of subcutaneous implantable cardioverter defibrillators (S-ICDs) acknowledges that 'deep implants' may fail to elicit a magnet response, however, does not define 'deep implant' or recommend a maximum implant depth. This study aims to systematically evaluate the effect of subcutaneous tissue depth and magnet types on evoked magnet response. METHODS: Sunshine Coast University Hospital's S-ICD cohort underwent magnet response evaluation; where bar and donut magnets were compared and the evoked magnet response was recorded in three separate zones, guided by a template. Ordinal regression (OR) models assessed the relationship between the evoked magnet response and tissue depth (TD), measured via post-implant X-Ray. The patient's ability to hear the magnet response audible tone was recorded. RESULTS: Patients (n = 39) with measurable TD (n = 30) were analyzed. The bar magnet evoked a magnet response in all zones in 53% of patients, compared with 73% of patients with the donut magnet (p = 0.18). The relationship between bar magnet response and TD showed the odds of an evoked magnet response decreased by 11% every 1 mm increase in TD (OR of 0.89, p < 0.01), whereas the donut magnet decreased by 16% per 1 mm (OR of 0.84, p < 0.01). Directly over the S-ICD was the most effective in evoking magnet response with the bar (85% of patients), and off-centre was most effective for the donut magnet (100%). BMI and Praetorian score were not significantly associated with magnet response. We found 23% of patients were unable to detect the audible tone. CONCLUSION: We observed a statistically significant association between TD and ability to evoke magnet response. The bar magnet was less reliable than the donut magnet for therapy inhibition in deep implants.

The Impact of Pre-Procedural Renal Impairment on Outcomes Following Percutaneous Coronary Intervention: An Analysis of 45,287 Patients From the British Columbia Cardiac Registry.

BACKGROUND: Renal disease confers a strong independent risk for morbidity and mortality after percutaneous coronary intervention (PCI). We evaluated the relationship between baseline pre-procedural renal function and outcomes following PCI. METHODS: We examined 45,287 patients who underwent PCI in British Columbia. We evaluated all-cause mortality and target vessel revascularisation (TVR) at 2 years. Pre-procedural renal impairment was categorised by creatinine clearance (CrCl, mL/min): CrCl≥90 (n=14,876), 90>CrCl≥60 (n=10,219), 60>CrCl≥30 (n=14,876), 30>CrCl≥0 (n=2,594) and dialysis (n=579). RESULTS: Declining CrCl values less than 60 mL/min were progressively associated with greater mortality: 60>eGFR≥30 (HR=2.01, 95% CI 1.71-2.37, p<0.001); 30>eGFR≥0 (HR=4.10, 95% CI 3.39-4.95, p<0.001); and dialysis (HR=6.22, 95% CI 5.07-7.63, p<0.001). A reduction in eGFR was not associated with TVR in non-dialysis patients. However, dialysis was a strong independent predictor for TVR (HR=1.69, 95% CI 1.37-2.08, p<0.001). This was confirmed in propensity-matched analyses where, dialysis was strongly associated with TVR (HR=1.53, 95% CI 1.24-1.89, p<0.001). This association was consistently seen in stratified analyses for diabetic versus non-diabetic patients; stent length >30 mm versus <30 mm; stent diameter >3 mm versus <3 mm; and receipt of bare metal stents versus drug-eluting stents. CONCLUSIONS: This study indicates the association with declining renal function and mortality in patients undergoing PCI. Whilst renal disease was not associated with increased TVR in non-dialysis patients, dialysis-dependence was a strong independent predictor for increased TVR.

Electrogram analysis to detect cathodal and anodal capture in left ventricular cardiac resynchronization pacing leads.

AIMS: Our study analyzed cardiac electrograms (EGMs) to identify characteristics for detecting cathodal, anodal, or cathodal-anodal (simultaneous) capture in left ventricular (LV) quadripolar pacing leads of cardiac resynchronization therapy (CRT) patients. The relationship between these EGM characteristics and the electrocardiogram (ECG) was also examined. METHODS: We performed a retrospective analysis of 54 bipolar pacing configurations across nine patients with implanted CRT devices and quadripolar leads who had undergone a 12 lead ECG optimization. Three pacing tests (cathode unipolar, anode unipolar, and bipolar) per bipolar pair were performed, examining ECG and EGM morphology changes accompanying each test and any transitions of morphology or amplitude during voltage stepdown. RESULTS: During the cathode and anode unipolar pacing tests, the EGM was biphasic (negative/positive) or monophasic (positive) in 52/53 (98%), and biphasic (positive/negative) or monophasic (negative) in 50/51 (98%), respectively. During bipolar LV capture threshold testing, 30 bipolar pairs displayed a sudden increase in EGM amplitude (median 9.4 mV, interquartile range [7-14 mV]) when transitioning from cathodal-anodal capture to cathodal or anodal capture. Ninety percent of these EGM transitions had a corresponding simultaneous change in ECG, while 10% had no ECG changes. Two patients demonstrated "quad-site" capture on their quadripolar lead with multipoint pacing enabled and cathodal-anodal capture from each stimulus. CONCLUSION: EGM characteristics during LV pacing tests can reliably detect cathodal, anodal, or cathodal-anodal capture, with greater sensitivity than 12 lead ECG changes. Integration of EGM analysis into routine CRT device follow up can be performed easily and may have implications for CRT efficacy.

Variation in key leaf photosynthetic traits across wheat wild relatives is accession dependent not species dependent.

The wild relatives of modern wheat represent an underutilized source of genetic and phenotypic diversity and are of interest in breeding owing to their wide adaptation to diverse environments. Leaf photosynthetic traits underpin the rate of production of biomass and yield and have not been systematically explored in the wheat relatives. This paper identifies and quantifies the phenotypic variation in photosynthetic, stomatal, and morphological traits in up to 88 wheat wild relative accessions across five genera. Both steady-state measurements and dynamic responses to step changes in light intensity are assessed. A 2.3-fold variation for flag leaf light and CO2 -saturated rates of photosynthesis Amax was observed. Many accessions showing higher and more variable Amax , maximum rates of carboxylation, electron transport, and Rubisco activity when compared with modern genotypes. Variation in dynamic traits was also significant; with distinct genus-specific trends in rates of induction of nonphotochemical quenching and rate of stomatal opening. We conclude that utilization of wild relatives for improvement of photosynthesis is supported by the existence of a high degree of natural variation in key traits and should consider not only genus-level properties but variation between individual accessions.

Baseline and residual SYNTAX score in predicting outcomes after acute infarct angioplasty.

AIMS: The aim of this study was to explore the utility of baseline SYNTAX score (bSS) and residual SYNTAX score (rSS) in predicting 12-month outcomes after primary percutaneous coronary intervention (PPCI). METHODS AND RESULTS: Five hundred and ninety all-comers with acute STEMI presenting for PPCI over a two-year period were identified. Of these, 173 were excluded because of unsuitability for SYNTAX score calculation for this study. Two experienced observers calculated the bSS and rSS. Mortality data were sourced from the government registry. Logistic regression was used to assess the predictive power of bSS and rSS for mortality. Sensitivity analysis and a Cox proportional hazards model were used to evaluate the best cut-off for increased mortality. Of the 417 patients analysed (mean age 59 years), 81% were male and 18% were known diabetics. At 12 months, the overall mortality rate was 5.5% (23/417). An rSS of >12 was associated with a 13.95% mortality rate. The hazard ratio for mortality was 3.88 (95% CI: 1.49-10.09, p=0.005) for rSS of >12 and 3.01 (95% CI: 1.18-7.64, p=0.02) for bSS >12. The odds ratio (OR) for mortality was 1.06 (95% CI: 1.02-1.11, p=0.009) for rSS and 1.05 (95% CI: 1.02-1.1, p=0.007) for bSS. CONCLUSIONS: In STEMI patients undergoing PPCI, both bSS and rSS can predict mortality at 12 months. Every point on the rSS confers an additional 6% mortality risk. Calculation of the rSS after culprit lesion intervention may help guide management of non-culprit lesions.

Arabidopsis HEAT SHOCK TRANSCRIPTION FACTORA1b overexpression enhances water productivity, resistance to drought, and infection.

Heat-stressed crops suffer dehydration, depressed growth, and a consequent decline in water productivity, which is the yield of harvestable product as a function of lifetime water consumption and is a trait associated with plant growth and development. Heat shock transcription factor (HSF) genes have been implicated not only in thermotolerance but also in plant growth and development, and therefore could influence water productivity. Here it is demonstrated that Arabidopsis thaliana plants with increased HSFA1b expression showed increased water productivity and harvest index under water-replete and water-limiting conditions. In non-stressed HSFA1b-overexpressing (HSFA1bOx) plants, 509 genes showed altered expression, and these genes were not over-represented for development-associated genes but were for response to biotic stress. This confirmed an additional role for HSFA1b in maintaining basal disease resistance, which was stress hormone independent but involved H2O2 signalling. Fifty-five of the 509 genes harbour a variant of the heat shock element (HSE) in their promoters, here named HSE1b. Chromatin immunoprecipitation-PCR confirmed binding of HSFA1b to HSE1b in vivo, including in seven transcription factor genes. One of these is MULTIPROTEIN BRIDGING FACTOR1c (MBF1c). Plants overexpressing MBF1c showed enhanced basal resistance but not water productivity, thus partially phenocopying HSFA1bOx plants. A comparison of genes responsive to HSFA1b and MBF1c overexpression revealed a common group, none of which harbours a HSE1b motif. From this example, it is suggested that HSFA1b directly regulates 55 HSE1b-containing genes, which control the remaining 454 genes, collectively accounting for the stress defence and developmental phenotypes of HSFA1bOx.

Antisense suppression of the small chloroplast protein CP12 in tobacco alters carbon partitioning and severely restricts growth.

The thioredoxin-regulated chloroplast protein CP12 forms a multienzyme complex with the Calvin-Benson cycle enzymes phosphoribulokinase (PRK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). PRK and GAPDH are inactivated when present in this complex, a process shown in vitro to be dependent upon oxidized CP12. The importance of CP12 in vivo in higher plants, however, has not been investigated. Here, antisense suppression of CP12 in tobacco (Nicotiana tabacum) was observed to impact on NAD-induced PRK and GAPDH complex formation but had little effect on enzyme activity. Additionally, only minor changes in photosynthetic carbon fixation were observed. Despite this, antisense plants displayed changes in growth rates and morphology, including dwarfism and reduced apical dominance. The hypothesis that CP12 is essential to separate oxidative pentose phosphate pathway activity from Calvin-Benson cycle activity, as proposed in cyanobacteria, was tested. No evidence was found to support this role in tobacco. Evidence was seen, however, for a restriction to malate valve capacity, with decreases in NADP-malate dehydrogenase activity (but not protein levels) and pyridine nucleotide content. Antisense repression of CP12 also led to significant changes in carbon partitioning, with increased carbon allocation to the cell wall and the organic acids malate and fumarate and decreased allocation to starch and soluble carbohydrates. Severe decreases were also seen in 2-oxoglutarate content, a key indicator of cellular carbon sufficiency. The data presented here indicate that in tobacco, CP12 has a role in redox-mediated regulation of carbon partitioning from the chloroplast and provides strong in vivo evidence that CP12 is required for normal growth and development in plants.

The high light response in Arabidopsis involves ABA signaling between vascular and bundle sheath cells.

Previously, it has been shown that Arabidopsis thaliana leaves exposed to high light accumulate hydrogen peroxide (H2O2) in bundle sheath cell (BSC) chloroplasts as part of a retrograde signaling network that induces ASCORBATE PEROXIDASE2 (APX2). Abscisic acid (ABA) signaling has been postulated to be involved in this network. To investigate the proposed role of ABA, a combination of physiological, pharmacological, bioinformatic, and molecular genetic approaches was used. ABA biosynthesis is initiated in vascular parenchyma and activates a signaling network in neighboring BSCs. This signaling network includes the Galpha subunit of the heterotrimeric G protein complex, the OPEN STOMATA1 protein kinase, and extracellular H2O2, which together coordinate with a redox-retrograde signal from BSC chloroplasts to activate APX2 expression. High light-responsive genes expressed in other leaf tissues are subject to a coordination of chloroplast retrograde signaling and transcellular signaling activated by ABA synthesized in vascular cells. ABA is necessary for the successful adjustment of the leaf to repeated episodes of high light. This process involves maintenance of photochemical quenching, which is required for dissipation of excess excitation energy.

Potential of vitamin E as an antioxidant adjunct in Wilson's disease.

Wilson's disease is a rare genetic illness of copper metabolism, which leads to copper-overload in mitochondria and organ damage, especially to the liver. Oxidative stress is central to the pathogenesis and a case is briefly made for rigorous trials of vitamin E as an antioxidant adjunct based on earlier corollary studies of its levels in the blood and liver of Wilson's disease patients and its effects in animal models of the illness.

Imaging of reactive oxygen species in vivo.

Reactive oxygen species (ROS) are involved in many signalling pathways and numerous stress responses in plants. Consequently, it is important to be able to identify and localize ROS in vivo to evaluate their roles in signalling. A number of probes that have a high affinity for specific ROS and that are effectively taken up by cells and tissues are commercially available. Applications to intact leaves of singlet oxygen sensor green (SOSG), nitroblue tetrazolium (NBT), di-amino benzidine (DAB) and Amplex Red to detect singlet oxygen, superoxide and hydrogen peroxide are described. Imaging of the probes in the cells and tissues of leaves allows sites of ROS production to be identified.

Imaging the production of singlet oxygen in vivo using a new fluorescent sensor, Singlet Oxygen Sensor Green.

Singlet oxygen is known to be produced by cells in response to photo-oxidative stresses and wounding. Due to singlet oxygen being highly reactive, it is thought to have a very short half-life in biological systems and, consequently, it is difficult to detect. A new commercially available reagent (singlet oxygen sensor green, SOSG), which is highly selective for singlet oxygen, was applied to a range of biological systems that are known to generate singlet oxygen. Induction of singlet oxygen production by the addition of myoglobin to liposome preparations demonstrated that the singlet oxygen-induced increases in SOSG fluorescence closely followed the increase in the concentration of conjugated dienes, which is stoichiometrically related to singlet oxygen production. Applications of photo-oxidative stresses to diatom species and leaves, which are known to result in the production of singlet oxygen, produced large increases in SOSG fluorescence, as did the addition of 3-(3',4'-dichlorophenyl)1,1-dimethylurea (DCMU) to these systems, which inhibits electron transport in photosystem II and stimulates singlet oxygen production. The conditional fluorescent (flu) mutant of Arabidopsis produces singlet oxygen when exposed to light after a dark period, and this coincided with a large increase in SOSG fluorescence. Wounding of leaves was followed by an increase in SOSG fluorescence, even in the dark. It is concluded that SOSG is a useful in vivo probe for the detection of singlet oxygen.

Induction of ASCORBATE PEROXIDASE 2 expression in wounded Arabidopsis leaves does not involve known wound-signalling pathways but is associated with changes in photosynthesis.

ASCORBATE PEROXIDASE 2 (APX2) encodes a key enzyme of the antioxidant network. In excess light-stressed Arabidopsis leaves, photosynthetic electron transport (PET), hydrogen peroxide (H(2)O(2)) and abscisic acid (ABA) regulate APX2 expression. Wounded leaves showed low induction of APX2 expression, and when exposed to excess light, APX2 expression was increased synergistically. Signalling pathways dependent upon jasmonic acid (JA), chitosan and ABA were not involved in the wound-induced expression of APX2, but were shown to require PET and were preceded by a depressed rate of CO(2) fixation. This led to an accumulation of H(2)O(2) in veinal tissue. Diphenyl iodonium (DPI), which has been shown previously to be a potent inhibitor of H(2)O(2) accumulation in the veins of wounded leaves, prevented induction of APX2 expression probably by inhibition of PET. Thus, the weak induction of APX2 expression in wounded leaves may require H(2)O(2) and PET only. As in other environmental stresses, wounding of leaves resulted in decreased photosynthesis leading to increased reactive oxygen species (ROS) production. This may signal the induction of many 'wound-responsive' genes not regulated by JA-dependent or other known JA-independent pathways.

Endogenous superoxide production and the nitrite/nitrate ratio control the concentration of bioavailable free nitric oxide in leaves.

We have quantitatively measured nitric oxide production in the leaves of Arabidopsis thaliana and Vicia faba by adapting ferrous dithiocarbamate spin tapping methods previously used in animal systems. Hydrophobic diethyldithiocarbamate complexes were used to measure NO interacting with membranes, and hydrophilic N-methyl-d-glucamine dithiocarbamate was used to measure NO released into the external solution. Both complexes were able to trap levels of NO, readily detectable by EPR spectroscopy. Basal rates of NO production (in the order of 1 nmol g(-) (1) h(-1)) agreed with previous studies. However, use of methodologies that corrected for the removal of free NO by endogenously produced superoxide resulted in a significant increase in trapped NO (up to 18 nmol g(-) (1) h(-1)). Basal NO production in leaves is therefore much higher than previously thought, but this is masked by significant superoxide production. The effects of nitrite (increased rate) and nitrate (decreased rate) are consistent with a role for nitrate reductase as the source of this basal NO production. However, rates under physiologically achievable nitrite concentrations never approach that reported following pathogen induction of plant nitric-oxide synthase. In Hibiscus rosa sinensis, the addition of exogenous nitrite generated sufficient NO such that EPR could be used to detect its production using endogenous spin traps (forming paramagnetic dinitrosyl iron complexes). Indeed the levels of this nitrosylated iron pool are sufficiently high that they may represent a method of maintaining bioavailable iron levels under conditions of iron starvation, thus explaining the previously observed role of NO in preventing chlorosis under these conditions.

Control of Ascorbate Peroxidase 2 expression by hydrogen peroxide and leaf water status during excess light stress reveals a functional organisation of Arabidopsis leaves.

In Arabidopsis leaves, high light stress induces rapid expression of a gene encoding a cytosolic ascorbate peroxidase (APX2), whose expression is restricted to bundle sheath cells of the vascular tissue. Imaging of chlorophyll fluorescence and the production of reactive oxygen species (ROS) indicated that APX2 expression followed a localised increase in hydrogen peroxide (H2O2) resulting from photosynthetic electron transport in the bundle sheath cells. Furthermore, leaf transpiration rate also increased prior to APX2 expression, suggesting that water status may also be involved in the signalling pathway. Abscisic acid stimulated APX2 expression. Exposure of ABA-insensitive mutants (abi1-1, abi2-1) to excess light resulted in reduced levels of APX2 expression and confirmed a role for ABA in the signalling pathway. ABA appears to augment the role of H2O2 in initiating APX2 expression. This regulation of APX2 may reflect a functional organisation of the leaf to resolve two conflicting physiological requirements of protecting the sites of primary photosynthesis from ROS and, at the same time, stimulating ROS accumulation to signal responses to changes in the light environment.

Comparative study of tyrosine radicals in hemoglobin and myoglobins treated with hydrogen peroxide.

The reactions of hydrogen peroxide with human methemoglobin, sperm whale metmyoglobin, and horse heart metmyoglobin were studied by electron paramagnetic resonance (EPR) spectroscopy at 10 K and room temperature. The singlet EPR signal, one of the three signals seen in these systems at 10 K, is characterized by a poorly resolved, but still detectable, hyperfine structure that can be used to assign it to a tyrosyl radical. The singlet is detectable as a quintet at room temperature in methemoglobin with identical spectral features to those of the well characterized tyrosyl radical in photosystem II. Hyperfine splitting constants found for Tyr radicals were used to find the rotation angle of the phenoxyl group. Analysis of these angles in the crystal structures suggests that the radical resides on Tyr151 in sperm whale myoglobin, Tyr133 in soybean leghemoglobin, and either alphaTyr42, betaTyr35, or betaTyr130 in hemoglobin. In the sperm whale metmyoglobin Tyr103Phe mutant, there is no detectable tyrosyl radical present. Yet the rotation angle of Tyr103 (134 degrees) is too large to account for the observed EPR spectrum in the wild type. Tyr103 is the closest to the heme. We suggest that Tyr103 is the initial site of the radical, which then rapidly migrates to Tyr151.

Imaging of photo-oxidative stress responses in leaves.

High resolution digital imaging was used to identify sites of photo-oxidative stress responses in Arabidopsis leaves non-invasively, and to demonstrate the potential of using a suite of imaging techniques for the study of oxidative metabolism in planta. Tissue-specific photoinhibition of photosynthesis in individual chloroplasts in leaves was imaged by chlorophyll fluorescence microscopy. Singlet oxygen production was assessed by imaging the quenching of the fluorescence of dansyl-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrole (DanePy) that results from its reaction with singlet oxygen. Superoxide and hydrogen peroxide accumulation were visualized by the reduction of nitroblue tetrazolium (NBT) to formazan deposits and by polymerization with 3,3'-diaminobenzidine (DAB), respectively. Stress-induced expression of a gene involved with antioxidant metabolism was imaged from the bioluminescence from leaves of an Arabidopsis APX2-LUC transformant, which co-expresses an ascorbate peroxidase (APX2) with firefly luciferase. Singlet oxygen and superoxide production were found to be primarily located in mesophyll tissues whereas hydrogen peroxide accumulation and APX2 gene expression were primarily localized in the vascular tissues.