The prognostic significance of the electrical QRS axis on long-term mortality in acute coronary syndrome patients - The TACOS study.

INTRODUCTION: There are several potential causes of QRS-axis deviation in the ECG, but there is limited data on the prognostic significance of QRS-axis deviation in ACS patients. SUBJECTS AND METHODS: We evaluated the long-term prognostic significance of acute phase frontal plane QRS-axis deviation and its shift during hospital stay in ACS patients. A total of 1026 patients who met the inclusion criteria were divided into three categories: normal (n = 823), left (n = 166) and right/extreme axis (n = 37). RESULTS: The median survival time was 9.0 years (95% CI 7.9-10.0) in the normal, 3.6 years (95% CI 2.4-4.7) in the left and 1.3 years (95% CI 0.2-2.4) in the right/extreme axis category. Both short and long-term all-cause mortality was lowest in the normal axis category and highest in the right/extreme axis category. Compared to normal axis, both admission phase QRS-axis deviation groups were independently associated with a higher risk of all-cause mortality. When including left ventricular hypertrophy in the ECG, only the right/extreme axis retained its statistical significance (aHR 1.76; 95% CI 1.16-2.66, p = 0.007). Axis shift to another axis category had no effect on mortality. CONCLUSION: In ACS patients, acute phase QRS-axis deviation was associated with higher risk of all-cause mortality. Among the axis deviation groups, right/extreme QRS-axis deviation was the strongest predictor of mortality in the multivariable analysis. Further studies are required to investigate to what extent this association is caused by pre-existing or by ACS-induced axis deviations. QRS-axis shift during hospital stay had no effect on all-cause mortality.

Preprocessing Strategies for Sparse Infrared Spectroscopy: A Case Study on Cartilage Diagnostics.

The aim of the study was to optimize preprocessing of sparse infrared spectral data. The sparse data were obtained by reducing broadband Fourier transform infrared attenuated total reflectance spectra of bovine and human cartilage, as well as of simulated spectral data, comprising several thousand spectral variables into datasets comprising only seven spectral variables. Different preprocessing approaches were compared, including simple baseline correction and normalization procedures, and model-based preprocessing, such as multiplicative signal correction (MSC). The optimal preprocessing was selected based on the quality of classification models established by partial least squares discriminant analysis for discriminating healthy and damaged cartilage samples. The best results for the sparse data were obtained by preprocessing using a baseline offset correction at 1800 cm-1, followed by peak normalization at 850 cm-1 and preprocessing by MSC.

Preclassification of Broadband and Sparse Infrared Data by Multiplicative Signal Correction Approach.

Preclassification of raw infrared spectra has often been neglected in scientific literature. Separating spectra of low spectral quality, due to low signal-to-noise ratio, presence of artifacts, and low analyte presence, is crucial for accurate model development. Furthermore, it is very important for sparse data, where it becomes challenging to visually inspect spectra of different natures. Hence, a preclassification approach to separate infrared spectra for sparse data is needed. In this study, we propose a preclassification approach based on Multiplicative Signal Correction (MSC). The MSC approach was applied on human and the bovine knee cartilage broadband Fourier Transform Infrared (FTIR) spectra and on a sparse data subset comprising of only seven wavelengths. The goal of the preclassification was to separate spectra with analyte-rich signals (i.e., cartilage) from spectra with analyte-poor (and high-matrix) signals (i.e., water). The human datasets 1 and 2 contained 814 and 815 spectra, while the bovine dataset contained 396 spectra. A pure water spectrum was used as a reference spectrum in the MSC approach. A threshold for the root mean square error (RMSE) was used to separate cartilage from water spectra for broadband and the sparse spectral data. Additionally, standard noise-to-ratio and principle component analysis were applied on broadband spectra. The fully automated MSC preclassification approach, using water as reference spectrum, performed as well as the manual visual inspection. Moreover, it enabled not only separation of cartilage from water spectra in broadband spectral datasets, but also in sparse datasets where manual visual inspection cannot be applied.

The Effect of Atrial Fibrillation on the Long-Term Mortality of Patients with Acute Coronary Syndrome: The TACOS Study.

INTRODUCTION: Atrial fibrillation (AF) is a frequent finding in acute coronary syndrome (ACS), but there is conflicting scientific evidence regarding its long-term impact on patient outcome. The aim of this study was to survey and compare the ≥10-year mortality of ACS patients with sinus rhythm (SR) and AF. METHODS: Patients were divided into 2 groups based on rhythm in their 12-lead ECGs: (1) SR (n = 788) at hospital admission and discharge (including sinus bradycardia, physiological sinus arrhythmia, and sinus tachycardia) and (2) AF/atrial flutter (n = 245) at both hospital admission and discharge, or SR and AF combination. Patients who failed to match the inclusion criteria were excluded from the final analysis. The main outcome surveyed was long-term all-cause mortality between AF and SR groups during the whole follow-up time. RESULTS: Consecutive ACS patients (n = 1,188, median age 73 years, male/female 58/42%) were included and followed up for ≥10 years. AF patients were older (median age 77 vs. 71 years, p < 0.001) and more often female than SR patients. AF patients more often presented with non-ST-elevation myocardial infarction (69.8 vs. 50.4%, p < 0.001), had a higher rate of diabetes (31.0 vs. 22.8%, p = 0.009), and were more often using warfarin (32.2 vs. 5.1%, p < 0.001) or diuretic medication (55.1 vs. 25.8%, p < 0.001) on admission than patients with SR. The use of warfarin at discharge was also more frequent in the AF group (55.5 vs. 14.8%, p < 0.001). The rates of all-cause and cardiovascular mortality were higher in the AF group (80.9 vs. 50.3%, p < 0.001, and 73.8 vs. 69.6%, p = 0.285, respectively). In multivariable analysis, AF was independently associated with higher mortality when compared to SR (adjusted HR 1.662; 95% CI: 1.387-1.992, p < 0.001). CONCLUSION: AF/atrial flutter at admission and/or discharge independently predicted poorer long-term outcome in ACS patients, with 66% higher mortality within the ≥10-year follow-up time when compared to patients with SR.

Long-term outcome of pre-specified ECG patterns in acute coronary syndrome.

BACKGROUND: Long-term outcome of real-life acute coronary syndrome (ACS) patients with selected ECG patterns is not well known. PURPOSE: To survey the 10-year outcome of pre-specified ECG patterns in ACS patients admitted to a university hospital. METHODS: A total of 1184 consecutive acute coronary syndrome patients in 2002-2003 were included and followed up for 10 years. The patients were classified into nine pre-specified ECG categories: 1) ST elevation; 2) pathological Q waves without ST elevation; 3) left bundle branch block (LBBB); 4) right bundle branch block (RBBB) 5) left ventricular hypertrophy (LVH) without ST elevation except in leads aVR and/or V1; 6) global ischemia ECG (ST depression ≥0.5 mm in 6 leads, maximally in leads V4-5 with inverted T waves and ST elevation ≥0.5 mm in lead aVR); 7) other ST depression and/or T wave inversion; 8) other findings and 9) normal ECG. RESULTS: Any abnormality in the ECG, especially Q waves, LBBB, LVH and global ischemia, had negative effect on outcome. In age- and gender adjusted Cox regression analysis, pathological Q waves (HR 2.28, 95%CI 1.20-4.32, p = .012), LBBB (HR 3.25, 95%CI 1.65-6.40, p = .001), LVH (HR 2.53, 95%CI 1.29-4.97, p = .007), global ischemia (HR 2.22, 95%CI 1.14-4.31, p = .019) and the combined group of other findings (HR 3.01, 95%CI 1.56-6.09, p = .001) were independently associated with worse outcome. CONCLUSIONS: During long-term follow-up of ACS patients, LBBB, ECG-LVH, global ischemia, and Q waves were associated with worse outcome than a normal ECG, RBBB, ST elevation or ST depression with or without associated T-wave inversion. LBBB was associated with the highest mortality rates.

WS2 and MoS2 thin film gas sensors with high response to NH3 in air at low temperature.

Transition metal dichalcogenides (TMDs) have received immense research interest in particular for their outstanding electrochemical and optoelectrical properties. Lately, chemical gas sensor applications of TMDs have been recognized as well owing to the low operating temperatures of devices, which is a great advantage over conventional metal oxide based sensors. In this work, we elaborate on the gas sensing properties of WS2 and MoS2 thin films made by simple and straightforward thermal sulfurization of sputter deposited metal films on silicon chips. The sensor response to H2, H2S, CO and NH3 analytes in air at 30 °C has been assessed and both MoS2 and WS2 were found to have an excellent selectivity to NH3 with a particularly high sensitivity of 0.10 ± 0.02 ppm-1 at sub-ppm concentrations in the case of WS2. The sensing behavior is explained on the bases of gas adsorption energies as well as carrier (hole) localization induced by the surface adsorbed moieties having reductive nature.

Adjuvant radiotherapy-induced cardiac changes among patients with early breast cancer: a three-year follow-up study.

Background: In this study, we evaluate the evolution of cardiac changes during a three-year follow-up after adjuvant breast radiotherapy (RT). Methods: Sixty patients with left-sided and 20 patients with right-sided early stage breast cancer without chemotherapy were included in this prospective study. Echocardiography and cardiac biomarkers were evaluated before, immediately after and 3 years after RT. Radiation doses to cardiac structures were calculated. Results: In echocardiography, left ventricle (LV) systolic measurements had impaired at 3 years compared to baseline: the mean global longitudinal strain (GLS) worsened from -18 ± 3 to -17 ± 3 (p = .015), LV ejection fraction from 62 ± 5% to 60 ± 4% (p = .003) and the stroke volume from 73 ± 16 mL to 69 ± 15 mL (p = .015). LV diastolic function was also negatively affected: the isovolumetric relaxation time was prolonged (p = .006) and the first peak of diastole decreased (p = .022). Likewise, left atrial (LA) measurements impaired. These changes in echocardiography were more prominent in left-sided than in right-sided patients. The concurrent aromatase inhibitor (AI) use was associated with GLS impairment. In all patients, the N-terminal pro-brain natriuretic peptide (proBNP) values were median (interquartile range) 74 (41-125) ng/L at baseline, 75 (41-125) ng/L at the end of RT and 96 (56-162) ng/L at 3 years (p < .001 from baseline to 3 years). However, proBNP did not increase in right-sided patients. Conclusion: During the 3-year follow-up after RT, negative subclinical changes in cardiac biomarkers and in LV systolic and diastolic function were observed. The measured changes were more pronounced in left-sided patients. In addition, AI use was associated with impaired cardiac systolic function.

Towards microbioprocess control: an inexpensive 3D printed microbioreactor with integrated online real-time glucose monitoring.

Bioprocessing is of crucial importance in pharmaceutical, biofuel, food and other industries. Miniaturization of bioprocesses into microbioreactors allows multiplexing of experiments as well as reduction of reagent consumption and labour-intensity. A crucial part of the research within microbioreactors is biochemical analysis of product, byproduct and substrate concentrations that currently heavily relies on large analytical equipment. Biosensors are a promising analytical tool, however, integration into a microbioreactor is associated with challenges in ensuring sterility, appropriate sensing range, control of matrix effects and stability. In this work we present a novel biosensor integrated analytical chip that features an internal, actuated buffer flow in contact with a biosensor downstream and a diffusion limiting membrane exposed to the sample upstream. The technology was developed and tested using an electrochemical glucose oxidase biosensor and was found to successfully surmount the aforementioned challenges including the extension of the linear range of sensitivity to more than 20 g L-1 for online, real time monitoring of glucose. The biosensor integration chip with the glucose biosensor was then mounted onto a 3D printed microbioreactor with 1 mL of internal volume. The system successfully monitored the consumption of glucose of Saccharomyces cerevisiae in real time for more than 8 h. The developed technology and measurement methodologies are transferrable to other biosensors and microbioreactors as well as large scale applications.

Associations between ECG changes and echocardiographic findings in patients with acute non-ST elevation myocardial infarction.

BACKGROUND: ST segment depression (STD) and T wave inversion (TWI) are typical electrocardiographic (ECG) findings in non-ST elevation myocardial infarction (NSTEMI). In ST elevation myocardial infarction, ST changes represent transmural ischemia. The pathophysiological mechanisms of the ECG changes in NSTEMI are unclear. PURPOSE: We studied the associations between ECG and the echocardiographic findings in NSTEMI patients. METHODS: Twenty patients with acute NSTEMI were recruited during their hospital stay. A comprehensive echocardiography study was performed. The findings were compared with blinded ECG analyses. RESULTS: Nine (45%) patients had STD, and 16 (85%) patients had TWI. In multivariable analysis, STD was independently associated with a lower global early diastolic strain rate (ß=-5.061, p=0.033). TWI was independently associated with lower circumferential strain (ß=0.132, p=0.032). CONCLUSIONS: The typical ECG changes in NSTEMI patients were associated with subtle echocardiographic changes. STD was related to changes in diastolic function, and TWI was associated with systolic deterioration.

Detection of early radiotherapy-induced changes in intrinsic myocardial contractility by ultrasound tissue characterization in patients with early-stage breast cancer.

BACKGROUND: Increased cardiovascular morbidity and mortality are major late complications after radiotherapy (RT) in the thoracic region. Ultrasound tissue characterization (UTC) is a noninvasive method for the identification of myocardial changes. The aim of this prospective clinical trial was to assess whether the analysis of cyclic variation of integrated backscatter (CVIBS) can detect early RT-induced myocardial alterations. METHODS: Seventy-three eligible patients with early-stage breast cancer were evaluated before and immediately after adjuvant RT. Twenty and 53 patients had right-sided and left-sided breast cancer, respectively. None of the patients received chemotherapy. Comprehensive echocardiographic examination included three-dimensional (3D) measurements and UTC analysis of the left ventricular (LV) septum and posterior wall. RESULTS: RT reduced CVIBS in a dose-dependent manner. The mean heart radiation dose over two gray (Gy) reduced the septal CVIBS from 12.0±3.4 to 9.6±2.5 dB (P<.001) and the posterior wall CVIBS from 12.8±2.7 to 11.3±2.4 dB (P=.007). The CVIBS remained unchanged when the mean heart RT dose was below 2 Gy. Multivariate analysis showed an independent association with a change in septal CVIBS and the use of aromatase inhibitor (ß=2.986, P=.001) and body mass index (ß=-0.241, P=.014). The posterior values were worse with higher mean lung dose (ß=-.485, P=.018) and with nonsmoking status (ß=-2.411, P=.009). Echocardiography parameters showed increased myocardial mass but conventional measurements of the LV systolic function remained unchanged. CONCLUSIONS: Cyclic variation of integrated backscatter analysis seems to be a sensitive method to detect early RT-induced myocardial changes. Hence, it may be useful in screening of patients needing closer follow-up.

Cardiac pacemakers in magnetic fields of a shunt reactor at a 400†kV substation.

The use of cardiac pacemakers (PMs) increases in Western countries. The aim of the study is to investigate cardiac pacemakers (PMs) using a human-shaped phantom in magnetic fields of a shunt reactor at a 400 kV substation. We performed seven PM experiments using a phantom. Two locations close to the shunt reactors were chosen. The magnetic field exposure was over 1000 µT in one location and over 600 µT in the other one. The magnetic field exposure did not disturb the tested five different PMs (in unipolar or bipolar configurations). It can be stated that in our experiment, the magnetic field exposure (over 600 µT and over 1000 µT) did not disturb the PMs (in unipolar or bipolar configurations). Since we only studied some PMs, it is possible that the magnetic field exposure at 400 kV substations can cause disturbances to other PMs. However, the risk of disturbances does not seem to be high.

Implantable cardioverter defibrillators in electric and magnetic fields of 400 kV power lines.

BACKGROUND: Implantable cardioverter defibrillator (ICD) therapy has increased in Western countries. The aim of the study was to investigate the function of ICDs using a human-shaped phantom in electric and magnetic fields of 400 kV power lines. METHODS: The phantom was used in the following manner: isolated from the ground, earthed from a foot, or earthed from a hand. RESULTS: We performed 37 ICD tests using 10 different ICD devices. When the electric fields varied from 6.8 kV/m to 7.5 kV/m (humidity 70.5%) and the magnetic field was 2.0 µT, one of the ICDs tested recorded 258 ventricular beats/min when a simulated heart signal was applied to ICD electrodes. When the exposure was 5.1 kV/m, the same ICD had a similar disturbance; however, in a 0.9 kV/m field, it worked correctly. CONCLUSIONS: Consequently, no effect on ICDs functioning was observed up to 0.9 kV/m, while anomalous behavior in some conditions was observed when levels exceeded 5.1 kV/m; ICD malfunctioning seems possible within 11.5 m from 400 kV power lines or in conditions inducing exposures exceeding 5 kV/m. Further development of this research field is needed.

[Update on current care guideline: atrial fibrillation]. / Eteisvärinä.

The prevalence and incidence of atrial fibrillation (AF) are increasing rapidly. Key recommendations in management of AF include prompt administration of oral anticoagulation to all patients with elevated risk of thromboembolic complications, proper use of antiarrhythmic drugs and invasive therapies in highly symptomatic patients and adequate rate control in patients with permanent AF. The selection between warfarin and the novel oral anticoagulants (apixaban, dabigatran, rivaroxaban) is based on careful evaluation of the benefits and disadvantages of the drugs in a given patient.

Development of a competitive immunoassay for the determination of cortisol in human saliva.

Two new protein conjugates were prepared and studied to develop and compare two (direct and indirect) competitive enzyme-linked immunosorbent assay (ELISA) formats for the determination of cortisol in human saliva. Toward this goal, ovalbumin was conjugated to cortisol and used for developing an indirect competitive ELISA, while alkaline phosphatase was coupled with the same analyte for a direct competitive assay. The yield of the conjugation reactions was evaluated. The results obtained show that the indirect and direct ELISA formats developed for cortisol had working ranges of 0.5-70 and 2-330 ng/ml and detection limits of 0.5 and 1.2 ng/ml, respectively. Artificial and real saliva samples were spiked with cortisol to study the matrix effect of saliva. The suitability of the assays for quantification of cortisol in saliva was also studied.

Characterisation of Cartilage Damage via Fusing Mid-Infrared, Near-Infrared, and Raman Spectroscopic Data.

Mid-infrared spectroscopy (MIR), near-infrared spectroscopy (NIR), and Raman spectroscopy are all well-established analytical techniques in biomedical applications. Since they provide complementary chemical information, we aimed to determine whether combining them amplifies their strengths and mitigates their weaknesses. This study investigates the feasibility of the fusion of MIR, NIR, and Raman spectroscopic data for characterising articular cartilage integrity. Osteochondral specimens from bovine patellae were subjected to mechanical and enzymatic damage, and then MIR, NIR, and Raman data were acquired from the damaged and control specimens. We assessed the capacity of individual spectroscopic methods to classify the samples into damage or control groups using Partial Least Squares Discriminant Analysis (PLS-DA). Multi-block PLS-DA was carried out to assess the potential of data fusion by combining the dataset by applying two-block (MIR and NIR, MIR and Raman, NIR and Raman) and three-block approaches (MIR, NIR, and Raman). The results of the one-block models show a higher classification accuracy for NIR (93%) and MIR (92%) than for Raman (76%) spectroscopy. In contrast, we observed the highest classification efficiency of 94% and 93% for the two-block (MIR and NIR) and three-block models, respectively. The detailed correlative analysis of the spectral features contributing to the discrimination in the three-block models adds considerably more insight into the molecular origin of cartilage damage.

Radiotherapy-induced diffuse myocardial fibrosis in early-stage breast cancer patients - multimodality imaging study with six-year follow-up.

BACKGROUND: Breast radiotherapy (RT) induces diffuse myocardial changes, which may increase the incidence of heart failure with preserved ejection fraction. This study aimed to evaluate the early signs of diffuse fibrosis after RT and their evolution during a six-year follow-up. METHODS: Thirty patients with early-stage left-sided breast cancer were studied with echocardiography and electrocardiography (ECG) at baseline, after RT, and at three-year and six-year follow-up visits. Echocardiography analysis included an off-line analysis of integrated backscatter (IBS). ECG was analysed for fragmented QRS (fQRS). In addition, cardiac magnetic resonance (CMR) imaging was performed at the six-year control. The left ventricle 16-segment model was used in cardiac imaging, and respective local radiation doses were analysed. RESULTS: Regional myocardial reflectivity in inferoseptal segments increased by 2.02 (4.53) dB (p = 0.026) and the percentage of leads with fQRS increased from 9.2 to 16.4% (p = 0.002) during the follow-up. In CMR imaging, abnormal extracellular volume (ECV) and T1 mapping values were found with anteroseptal and apical localization in a median of 3.5 (1.00-5.75) and 3 (1.25-4.00) segments, respectively. A higher left ventricle radiation dose was associated with an increased likelihood of having changes simultaneously in CMR and echocardiography (OR 1.26, 95% Cl. 1.00-1.59, p = 0.047). CONCLUSIONS: After radiotherapy, progressive changes in markers of diffuse myocardial fibrosis were observed in a multimodal manner in ECG and echocardiography. Changes in echocardiography and abnormal values in CMR were localized in the septal and apical regions, and multiple changes were associated with higher radiation doses.

Highly Selective H2S Gas Sensor Based on Ti3C2Tx MXene-Organic Composites.

Cost-effective and high-performance H2S sensors are required for human health and environmental monitoring. 2D transition-metal carbides and nitrides (MXenes) are appealing candidates for gas sensing due to good conductivity and abundant surface functional groups but have been studied primarily for detecting NH3 and VOCs, with generally positive responses that are not highly selective to the target gases. Here, we report on a negative response of pristine Ti3C2Tx thin films for H2S gas sensing (in contrast to the other tested gases) and further optimization of the sensor performance using a composite of Ti3C2Tx flakes and conjugated polymers (poly[3,6-diamino-10-methylacridinium chloride-co-3,6-diaminoacridine-squaraine], PDS-Cl) with polar charged nitrogen. The composite, preserving the high selectivity of pristine Ti3C2Tx, exhibits an H2S sensing response of 2% at 5 ppm (a thirtyfold sensing enhancement) and a low limit of detection of 500 ppb. In addition, our density functional theory calculations indicate that the mixture of MXene surface functional groups needs to be taken into account to describe the sensing mechanism and the selectivity of the sensor in agreement with the experimental results. Thus, this report extends the application range of MXene-based composites to H2S sensors and deepens the understanding of their gas sensing mechanisms.

Cardiac pacemakers in electric and magnetic fields of 400-kV power lines.

BACKGROUND: The cardiac pacemaker (PM) implantation rate per million is high. Earlier studies have found interference to PMs by electromagnetic fields. The aim of the study is to investigate disturbances in cardiac PM using a human-shaped phantom in electric and magnetic fields of 400-kV power lines. METHODS: The phantom was used in the following manner: isolated from the ground, grounded from left or right foot, or grounded from left or right hand. RESULTS: Out of the tested PMs one had such a disturbance that it set the pace 60 times per minute, when the electric field was 6.7-7.5 kV/m and the magnetic field was 2.4-2.9 µT. The electrode configuration of the PM was unipolar. In bipolar configuration, the same PM had no disturbance. During the test period, other PMs only had minor disturbances or none at all. Some PMs do not record time information for minor disturbances. In such cases, it was impossible to link the disturbances to the exposure under the power line. CONCLUSIONS: The electric field under a 400-kV power line may disturb a PM. However, only one type out of several tested PMs showed a major disturbance and that was only with a unipolar electrode configuration. The risk of disturbances is therefore not deemed to be high.

Vitamin C inhibits staphylococcus aureus growth and enhances the inhibitory effect of quercetin on growth of Escherichia coli in vitro.

Quercetin is a natural flavonoid possessing a number of health beneficial effects. Its bioactivity is restricted by low solubility and sensitivity to oxidative degradation, factors that are often ignored in laboratory studies. We studied the antimicrobial effects of quercetin on Staphylococcus aureus, Escherichia coli and Lactobacillus plantarum at concentrations at which it is soluble and investigated how the antioxidant vitamin C modulates these activities. S. aureus was the most sensitive of the studied bacteria. After 12 hours of culturing, 90 µM quercetin decreased the growth of S. aureus to 75 % of the value for a control culture. 1 mM vitamin C combined with 90 µM quercetin diminished the growth of S. aureus drastically to 3 % of that of the control culture supplemented with vitamin C only. Interestingly, vitamin C by itself inhibited the growth of S. aureus as well, and 5 mM vitamin C inhibited growth completely. The growth inhibition of E. coli was slightly but significantly better in the presence of both quercetin and vitamin C than in the presence of quercetin alone. Probiotic L. plantarum was resistant to quercetin in the presence and absence of vitamin C. Enhancement of quercetin's antimicrobial activity by vitamin C is partly explained by the stabilizing effect of vitamin C on quercetin. Even though the acidity of vitamin C contributes to the inhibition of S. aureus growth, neutralized vitamin C also inhibits the growth efficiently even without quercetin. Our results suggest that vitamin C affects the metabolism of S. aureus and that these changes are likely to result in the observed growth inhibition. Although vitamin C itself is a powerful antioxidant, its aerobic metabolism increases oxidative stress on bacterial cells. Vitamin C may therefore be a safe and natural alternative for restricting the growth of S. aureus when non-toxicity is required.

Chemical composition of ripe fruits of Rubus chamaemorus L. grown in different habitats.

BACKGROUND: Cloudberry (Rubus chamaemorus L.) is one of the most valuable berry-producing plants because of its nutritional properties. The chemical composition and crop yield of ripe fruits of cloudberry grown wild in 10 habitats in northern Finland was analysed over two consecutive summers. For comparison, two clones of cultivated cloudberries were studied as well. RESULTS: The concentrations of citric and malic acids, α-tocopherol, anthocyanins and ß-carotene had notable variations between habitats. In particularly, cloudberries grown on open habitats had higher content of citric acid and less α-tocopherol compared to those grown on shaded sites. In a colder and rainy summer the content of anthocyanins and the unsaturation level of fatty acids were significantly higher than in a warmer and drier summer. Crop yields were higher in the warmer summer, except in open sites where yields were quite equal. CONCLUSION: Cloudberries grown in open habitats showed notable differences in chemical composition when compared to those grown on shaded sites. Results suggest that the amount of sunlight and temperature levels could be the main factors affecting crop yield and chemical composition of cloudberry. In addition, the amount of rainfall may have an effect on anthocyanin concentrations.