The Role of Objective Movement Analysis in the Control of Yoga Asanas: A Case Study.

INTRODUCTION: Yoga is classified as a form of complementary and alternative medicine. It can be used in many disciplines including physiotherapy, medicine, and sport. The objective of the study was to identify possible biomechanical problems during yoga practice and to minimize the risk of injury. CASE PRESENTATION: Objective evaluation of the symmetry of asanas, balance, stability, and muscle tension was provided in case of a 37-year-old woman, practicing mainly aerial and Hatha yoga for 6 years. The bigger body tilt and deviations in center of pressure (COP) parameters were observed in tadasana during forward examinations. In tadasana, the highest muscle activity was observed in the rectus femoris. In case of forward tadasana observation, the highest activity was found in the gastrocnemius and in the lumbar portion of the erector spinae. During backward tadasana trial, the most active were the tibialis anterior and rectus femoris muscles. In garudasana and natarajasana, the symmetry of the trunk position in relation to the lower limbs was observed, regardless of the supporting limb. In the same way, COP parameters in garudasana were similar regardless of the supporting limb. However, in natarajasana, the higher COP displacement parameters were observed in the case of the nondominant supporting limb. As for the electromyographic evaluation of garudasana and natarajasana, the highest muscle activity was observed in the lumbar portion of the erector spinae. In chakrasana, a slightly greater angle of the hip extension was observed in the left hip. A higher muscle activity in chakrasana was observed in the lumbar portion of the right erector spinae. In sirsasana, no significant displacements of the cervical spine were observed, but a higher activity of the left sternocleidomastoid muscle was found. CONCLUSION: With the use of objective movement analysis, possible biomechanical problems were identified. Attention should be paid to the normalization of the tension in the lumbar part of the right erector spinae and the right sternocleidomastoid muscle, as well as to the balance training in positions on the nondominant lower limb. Objective movement analysis can be a useful tool for instructors or physiotherapists to adjust yoga programs and correct asanas in order to avoid future injuries.Yoga gilt als Form der Komplementär- und Alternativmedizin. Es ist in vielen Disziplinen einsetzbar, von Physiotherapie über Medizin bis Sport. Das Ziel dieser Studie war es, mögliche biomechanische Probleme bei der Ausübung von Yoga zu identifizieren, um das Verletzungsrisiko zu minimieren.Eine objektive Beurteilung der Symmetrie der Asanas, des Gleichgewichts, der Stabilität und der Muskelspannung erfolgte bei einer 37-jährigen Frau, die seit 6 Jahren hauptsächlich Aerial- und Hatha-Yoga praktiziert. Stärkere Körperneigung und Abweichungen bei Druckmittelpunkt-Parametern wurden in Tadasana bei der Vorwärts-Beobachtung festgestellt. In Tadasana wurde die höchste Muskelaktivität im Rectus femoris beobachtet. Bei der Tadasana-Vorwärts-Beobachtung war die höchste Aktivität im Gastrocnemius und im lumbalen Anteil des Erector spinae zu verzeichnen. Während der Tadasana-Rückwärts-Übung waren die aktivsten Muskeln der Tibialis anterior und Rectus femoris. In Garudasana und Natarajasana wurde die Symmetrie der Rumpfposition im Verhältnis zu den unteren Gliedmaßen unabhängig von der belasteten Gliedmaße beobachtet. Ebenso waren die Parameter des Druckmittelpunkts (DMP) in Garudasana unabhängig von der belasteten Gliedmaße vergleichbar. In Natarajasana wurden jedoch höhere Parameter der DMP-Verschiebung bei der nicht-dominanten belasteten Gliedmaße beobachtet. Bei der elektromyografischen Auswertung von Garudasana und Natarajasana wurde die höchste Muskelaktivität im lumbalen Anteil des Erector spinae beobachtet. In Chakrasana wurde ein etwas größerer Winkel der Hüftstreckung im linken Hüftgelenk beobachtet. Eine höhere Muskelaktivität in Chakrasana wurde im lumbalen Anteil des rechten Erector spinae beobachtet. In Sirsasana wurden keine signifikanten Verschiebungen der Halswirbelsäule beobachtet, jedoch war eine höhere Aktivität des linken Sternocleidomastoideus zu verzeichnen.Mit Hilfe einer objektiven Bewegungsanalyse wurden mögliche biomechanische Probleme identifiziert. Mit besonderer Aufmerksamkeit sollte auf die Normalisierung der Spannung im lumbalen Anteil des rechten Erector spinae und des rechten Sternocleidomastoideus sowie auf die Schulung des Gleichgewichts in Positionen auf der nicht-dominanten unteren Extremität geachtet werden. Die objektive Bewegungsanalyse kann ein nützliches Instrument für Instruktoren oder Physiotherapeuten sein, um Yoga-Programme anzupassen und Asanas zu korrigieren, um Verletzungen vorzubeugen.

Effect of Exercise Repetitions on Arylesterase Activity of PON1 in Plasma of Average-Trained Men-The Dissociation between Activity and Concentration.

Exercise may increase the antioxidant capacity of plasma by stimulating antioxidant enzymes. The study aimed to measure the effect of three repetitions of acute exercise on arylesterase (ARE) activity of the paraoxonase 1 (PON1) enzyme. Eleven average-trained men (age 34.0 ± 5.2 years) completed three treadmill runs. ARE activity in plasma was evaluated spectrophotometrically and compared with PON1 concentration (PON1c), paraoxonase (PON) activity, and high-density lipoprotein cholesterol (HDL-C) at rest and after exercise. In all repetitions of the exercise, ARE activity remained stable, and ARE activity standardized for PON1c (ARE/PON1c) was lower post- than pre-exercise. The ARE/PON1c ratio changes returned to baseline levels during rest after each exercise session. Pre-exercise ARE activity correlated negatively with post-exercise C-reactive protein (CRP) (ρ = -0.35, p = 0.049), white blood cell count (WBC) (ρ = -0.35, p = 0.048), polymorphonuclear leukocytes (PMN) (ρ = -0.37, p = 0.037), and creatine kinase (CK) (ρ = -0.37, p = 0.036). ARE activity may be depleted under conditions of oxidative stress, as increases in PON1c during acute exercise did not result in parallel increases in ARE activity. No adaptation of the response of ARE activity to exercise was detected in subsequent exercise sessions. Individuals with lower pre-exercise ARE activity may develop a higher inflammatory response to strenuous exercise.

Interleukin-4 during post-exercise recovery negatively correlates with the production of phagocyte-generated oxidants.

Exhaustive run induced a biphasic oxidative response of circulating phagocytes in 16 amateur sportsmen. The first phase involved an increment just after exercise of enhanced whole blood chemiluminescence normalized per phagocyte count, whereas in the second phase a decrement from 1 h post-exercise and ongoing till 24 h. We tested whether plasma Interleukin IL-4, IL-8, IL-10 and Tumor Necrosis Factor α concentrations change in response to exhaustive run and whether there are associations between their levels and delta resting. Moreover, IL-8 and IL-10 significantly increased immediately post-exercise and after 1 h, but later normalized. Tumor necrosis factor α rose by 1.1-times only just after exercise. However, none of these cytokines showed any correlation with the investigated chemiluminescence. Exercise did not alter plasma concentrations of IL-4. However, pre-exercise IL-4 negatively correlated with measured luminescence just after exercise (ρ = -0.54, p < 0.05), and also tended to be negatively associated with decrements of the second phase at 1 h post-exercise ρ = -0.45, p = 0.08. It is suggested that plasma IL-4, by a negative association with blood phagocytes oxidants production, could be involved in the maintenance of proper balance between oxidants and anti-oxidants during strenuous exercise and post-exercise recovery.

Exhaustive Exercise Increases Spontaneous but Not fMLP-Induced Production of Reactive Oxygen Species by Circulating Phagocytes in Amateur Sportsmen.

Strenuous exercise alters the oxidative response of blood phagocytes to various agonists. However, little is known about spontaneous post exercise oxidant production by these cells. In this cross-over trial, we tested whether an exhaustive treadmill run at a speed corresponding to 70% of VO2max affects spontaneous and fMLP-provoked oxidant production by phagocytes in 18 amateur sportsmen. Blood was collected before, just after, and 1, 3, 5 and 24 h post exercise for determination of absolute and normalized per phagocyte count spontaneous (a-rLBCL, rLBCL) and fMLP-induced luminol-enhanced whole blood chemiluminescence (a-fMLP-LBCL, fMLP-LBCL). a-rLBCL and rLBCL increased by 2.5- and 1.5-times just after exercise (p < 0.05) and then returned to baseline or decreased by about 2-times at the remaining time-points, respectively. a-fMLP-LBCL increased 1.7- and 1.6-times just after and at 3 h post-exercise (p < 0.05), respectively, while fMLP-LBCL was suppressed by 1.5- to 2.3-times at 1, 3, 5 and 24 h post-exercise. No correlations were found between elevated post-exercise a-rLBCL, a-fMLP-LBCL and run distance to exhaustion. No changes of oxidants production were observed in the control arm (1 h resting instead of exercise). Exhaustive exercise decreased the blood phagocyte-specific oxidative response to fMLP while increasing transiently spontaneous oxidant generation, which could be a factor inducing secondary rise in antioxidant enzymes activity.

Repetitions of Strenuous Exercise Consistently Increase Paraoxonase 1 Concentration and Activity in Plasma of Average-Trained Men.

OBJECTIVES: Oxidative stress, induced by physical activity, may stimulate the expression, release, and activity of certain antioxidant enzymes. We investigated the effect of three repeated bouts of strenuous exercise on paraoxonase 1 concentration (PON1c) and paraoxonase activity (PON). METHODS: Eleven average-trained healthy men (age 34.0 ± 5.2 years) performed three strenuous exercise tests on a treadmill separated by 72 hours periods of resting. PON1c, PON, ferric-reducing activity of plasma (FRAP), lipid profile, C-reactive protein concentration (CRP), and lactate concentration were determined in plasma. RESULTS: Each exercise bout resulted in similar PON1c, PON, FRAP, and high-density lipoprotein concentration (HDL-C) increments, while PON/HDL-C ratio remained stable in all repetitions. Percentage increments at the bout of each exercise were higher for PON1c (by 64.82% at the first, by 92.9% at the second, and by 77.02% at the third exercise) than for PON (by 6.49% at the first, 10.06% at the second, and by 12.32% at the third exercise). Association was found between preexercise PON and PON1c (r = 0.56, p = 0.029), pre- (r = 0.87, p = 0.00003) and postexercise HDL-C (r = 0.6, p = 0.0002), preexercise PON and cardiovascular fitness level of participants measured as VO2max (r = 0.39, p = 0.026), and postexercise PON and lactate concentration (r = 0.44, p = 0.01). CONCLUSIONS: PON1c and PON increase during strenuous exercise, yet the effect of exercise on PON1 concentration is more pronounced. PON1 does not show tolerance to physical activity. The enzyme may provide short-term protection from oxidative stress in each exercise bout. PON may depend on exercise load. Cardiovascular fitness levels may be associated with PON1 activity.

Increased Circulating H3 Histone in Response to Repeated Bouts of Exercise Does Not Associate with Parallel Alterations of Cell-Free DNA.

Numerous studies have shown that cf nDNA significantly rises in stress caused by exercise. However, during nuclear decondensation, released DNA is followed by histones. Histones are also a common disease marker. After PAD4 mediated hypercitrullination extracellular H3Cit exhibits high toxicity contributing to tissue damage which, in cases of systemic inflammation, may lead to multiorgan failure and finally to death. We tested whether circulating histones rise in response to strenuous exercise. Eleven average-trained men performed three treadmill exercise tests to exhaustion at speed corresponding to 70% VO2max separated by 72 h of resting. Blood was collected before and just after each bout of exercise and plasma proteins were measured using enzyme-linked immunosorbent assay, whereas platelet activity was estimated with Light Transmission Aggregometry. Both, circulating histones and PAD4 raised in response to exercise. Plasma citrullinated histones increased from 3.1 ng/mL to 5.96 ng/mL (p = 0.0059), from 3.65 ng/mL to 6.37 ng/mL (p = 0.02), and from 3.86 ng/mL to 4.75 ng/mL (p = 0.033) after the first, second, and third treadmill run, respectively. However despite the parallel increase, no significant correlation between citrullinated histone and aggregation or cell-free nDNA was found. Furthermore, positive correlations of cf nDNA with aggregation and PAD4, lactate with aggregation, and lactate with citrullinated histone have been observed.

Circulating cell free DNA response to exhaustive exercise in average trained men with type I diabetes mellitus.

It is believed that neutrophils extracellular traps (NETs) formation is responsible for the increase in cf DNA after exercise. Since T1DM is accompanied by enhanced NETs generation, we compared exercise-induced increase in cf DNA in 14 men with T1DM and 11 healthy controls and analyzed its association with exercise load. Subjects performed a treadmill run to exhaustion at speed corresponding to 70% of their personal VO2max. Blood was collected before and just after exercise for determination of plasma cf nuclear and mitochondrial DNA (cf n-DNA, cf mt-DNA) by real-time PCR, blood cell count and metabolic markers. Exercise resulted in the increase in median cf n-DNA from 3.9 ng/mL to 21.0 ng/mL in T1DM group and from 3.3 ng/mL to 28.9 ng/mL in controls. Median exercise-induced increment (∆) in cf n-DNA did not differ significantly in both groups (17.8 ng/mL vs. 22.1 ng/mL, p = 0.23), but this variable correlated with run distance (r = 0.66), Δ neutrophils (r = 0.86), Δ creatinine (r = 0.65) and Δ creatine kinase (r = 0.77) only in controls. Pre- and post-exercise cf mt-DNA were not significantly different within and between groups. These suggest low usefulness of Δ cf n-DNA as a marker of exercise intensity in T1DM men.

Author Correction: Decreased integrity of exercise-induced plasma cell free nuclear DNA - negative association with the increased oxidants production by circulating phagocytes.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Decreased integrity of exercise-induced plasma cell free nuclear DNA - negative association with the increased oxidants production by circulating phagocytes.

Strenuous exercise increases circulating cell free DNA (cfDNA) and stimulates blood phagocytes to generate reactive oxygen species (ROS) which may induce DNA strand breaks. We tested whether: (A) elevated cfDNA in response to three repeated bouts of exhaustive exercise has decreased integrity; (B) each bout of exercise increases luminol enhanced whole blood chemiluminescence (LBCL) as a measure of ROS production by polymorphonuclear leukocytes. Eleven men performed three treadmill exercise tests to exhaustion separated by 72 hours of resting. Pre- and post-exercise concentrations and integrity of cf nuclear and mitochondrial DNA (cf n-DNA, cf mt-DNA) and resting (r) and fMLP (n-formyl-methionyl-leucyl-phenylalanine)-stimulated LBCL were determined. Each bout increased concentrations of cf n-DNA by more than 10-times which was accompanied by about 2-times elevated post-exercise rLBCL and fMLP-LBCL. Post-exercise cf n-DNA integrity (integrity index, I229/97) decreased after the first (0.59 ± 0.19 vs. 0.48 ± 0.18) and second (0.53 ± 0.14 vs. 0.44 ± 0.17) bout of exercise. There were negative correlations between I229/97 and rLBCL (ƍ = -0.37), and I229/97 and fMLP-LBCL (ƍ = -0.40) - analysis of pooled pre- and post-exercise data (n = 66). cf mt- DNA integrity (I218/78) did not alter in response to exercise. This suggests an involvement of phagocyte ROS in cf n-DNA strand breaks in response to exhaustive exercise.

Influenece of the CPRmeter on angular position of elbows and generated forces during cardiopulmonary resuscitation.

OBJECTIVES: It is commonly known that ergonomics in emergency medical services (EMS) is very important. Emergency medical services workers are exposed to different conditions and they should perform a variety of tasks. MATERIAL AND METHODS: The aim of the work has been to analyze the angular position of elbows and forces generated by the upper limbs during cardiopulmonary resuscitation with and without the CPRmeter based on feedback technology. Ten male paramedics and 10 male non-paramedics, in a kneeling position, performed cardiopulmonary resuscitation (CPR) on an Ambu Megacode manikin placed on the ground. Measurements were taken after 1 min and 4 min following the beginning of the trial. The angular position of the elbows was evaluated with a BTS Smart DX 7000 motion capture system. Kistler platforms 9286BA were used for measuring forces. RESULTS: In the paramedic group, one statistically significant difference was observed in the mean difference between maximal and minimal right elbow angle in the 1st min without the device vs. the mean difference in the 4th min without the device. In the paramedic group, a 25% force decrease was observed after 4 min of resuscitation in trials without the CPRmeter in comparison to the 1st min. In trials with the CPRmeter, the force parameters were similar in the 1st and 4th min and more stable. No statistically significant differences were noticed in the control group. CONCLUSIONS: The CPRmeter has influence on the magnitude of the forces applied by the upper limbs and on the optimization of the rescuer effort during cardiopulmonary resuscitation. The CPRmeter had no influence on the position of the upper part of the kinematic chain. Int J Occup Med Environ Health 2017;30(6):909-916.

Repeated bouts of exhaustive exercise increase circulating cell free nuclear and mitochondrial DNA without development of tolerance in healthy men.

OBJECTIVE: Acute single strenuous exercise increases circulating cell free DNA (cf DNA). We tested whether three repeated bouts of exhaustive exercise induced the cf DNA response without development of tolerance in healthy men. METHODS: Eleven average-trained men (age 34.0±5.2 years, body mass index 26.2±3.1 kg/m2, maximal oxygen consumption-VO2max 49.6±4.5 ml/kg*min) performed three treadmill exercise tests to exhaustion at speed corresponding to 70% VO2max separated by 72 hours of resting. Blood was collected before and after each bout of exercise for determination of cell free nuclear and mitochondrial DNA (cf n-DNA, cf mt-DNA) by real-time PCR, selected markers of muscle damage, and blood cell count. RESULTS: Each bout induced the increase (p<0.05) in plasma cf n-DNA: from 3.4±1.4 to 38.5±27.5, from 4.1±3.3 to 48.5±26.2, and 3.1±1.6 to 53.8±39.9 ng/mL after the first, second, and third exercise, respectively. In a congruent way, cf mt-DNA rose significantly after the second (from 229±216 to 450±228*103 GE/mL) and third bout of exercise (from 173±120 to 462±314*103 GE/mL). Pre-exercise cf mt-DNA decreased (p<0.05) by 2-times (from 355±219 before the first bout to 173±120*103 GE/mL before the third bout) over the study period and were accompanied by significant increase in white blood cells, platelets, creatine kinase, creatinine and lactate after each bout. However, the exercise induced percentage increment of cf n-DNA was always many times higher than corresponding increments of the afore-mentioned markers at any occasion. CONCLUSIONS: Repeated bouts of exhaustive exercise induced remarkable increase in circulating cf n-DNA without signs of tolerance development. Baseline cf mt-DNA decreased in response to series of strenuous exercise. Since percentage increments of cf n-DNA in response to exercise were many times higher than those observed for other markers, measurement of circulating cf n-DNA could be a sensitive tool for monitoring acute exercise effects in human body.

Electromyographic activity of masticatory muscles in elderly women - a pilot study.

OBJECTIVES: To evaluate the effect of age and chosen factors related to aging such as dentition, muscle strength, and nutrition on masticatory muscles electromyographic activity during chewing in healthy elderly women. BACKGROUND: With longer lifespan there is a need for maintaining optimal quality of life and health in older age. Skeletal muscle strength deteriorates in older age. This deterioration is also observed within masticatory muscles. METHODS: A total of 30 women, aged 68-92 years, were included in the study: 10 individuals had natural functional dentition, 10 were missing posterior teeth in the upper and lower jaw reconstructed with removable partial dentures, and 10 were edontoulous, using complete removable dentures. Surface electromyography was performed to evaluate masticatory muscles activity. Afterwards, measurement of masseter thickness with ultrasound imaging was performed, body mass index and body cell mass index were calculated, and isometric handgrip strength was measured. RESULTS: Isometric maximal voluntary contraction decreased in active masseters with increasing age and in active and passive temporalis muscles with increasing age and increasing body mass index. In active masseter, mean electromyographic activity during the sequence (time from the start of chewing till the end when the test food became ready to swallow) decreased with increasing age and during the cycle (single bite time) decreased with increasing age and increasing body mass index. In active and passive temporalis muscles, mean electromyographic activity during the sequence and the cycle decreased with increasing age, increasing body mass index, and loss of natural dentition. Individuals with natural dentition had significantly higher mean muscle activity during sequence and cycle in active temporalis muscles than those wearing full dentures and higher maximal activity during cycle in individuals with active and passive temporalis muscles than in complete denture wearers. CONCLUSION: Decrease in electromyographic activity of masticatory muscles in elderly women is related to age, deterioration of dental status, and body mass index.

Elevated exhalation of hydrogen peroxide in patients with non-small cell lung cancer is not affected by chemotherapy.

OBJECTIVES: Reactive oxygen species, which are implicated in the process of carcinogenesis, are also responsible for cell death during chemotherapy (CHT). Therefore, the aim of the study was to evaluate exhaled H2O2 levels in non-small cell lung cancer (NSCLC) patients before and after CHT. METHODS: Thirty patients (age 61.3 ± 9.3 years) with advanced NSCLC (stage IIIB-IV) and 15 age-matched healthy cigarette smokers were enrolled into the study. Patients received four cycles of cisplatin or carboplatin with vinorelbine every three weeks. Before and after the first, second, and fourth cycle, the concentration of H2O2 in exhaled breath condensate was measured with respect to treatment response. RESULTS: At the baseline, NSCLC patients exhaled 3.8 times more H2O2 than the control group (0.49 ± 0.14 vs. 0.13 ± 0.03 µmol/L, P < 0.05); this difference persisted throughout the study. CHT had no noticeable effect on exhaled H2O2 levels independent of the treatment response (partial remission vs. progressive disease). Pre- and post-CHT cycles of H2O2 levels generally correlated positively. DISCUSSION: The study demonstrated the occurrence of oxidative stress in the airways of advanced NSCLC patients. Exhaled H2O2 level was not affected by CHT and independent of treatment results and changes in the number of circulating neutrophils.

Consumption of strawberries on a daily basis increases the non-urate 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging activity of fasting plasma in healthy subjects.

Strawberries contain anthocyanins and ellagitanins which have antioxidant properties. We determined whether the consumption of strawberries increase the plasma antioxidant activity measured as the ability to decompose 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) in healthy subjects. The study involved 10 volunteers (age 41 ± 6 years, body weight 74.4 ± 12.7 kg) that consumed 500 g of strawberries daily for 9 days and 7 matched controls. Fasting plasma and spot morning urine samples were collected at baseline, during fruit consumption and after a 6 day wash-out period. DPPH decomposition was measured in both deproteinized native plasma specimens and pretreated with uricase (non-urate plasma). Twelve phenolics were determined with HPLC. Strawberries had no effect on the antioxidant activity of native plasma and circulating phenolics. Non-urate plasma DPPH decomposition increased from 5.7 ± 0.6% to 6.6 ± 0.6%, 6.5 ± 1.0% and 6.3 ± 1.4% after 3, 6 and 9 days of supplementation, respectively. The wash-out period reversed this activity back to 5.7 ± 0.8% (p<0.01). Control subjects did not reveal any changes of plasma antioxidant activity. Significant increase in urinary urolithin A and 4-hydroxyhippuric (by 8.7- and 5.9-times after 6 days of supplementation with fruits) was noted. Strawberry consumption can increase the non-urate plasma antioxidant activity which, in turn, may decrease the risk of systemic oxidants overactivity.

Uric acid but not apple polyphenols is responsible for the rise of plasma antioxidant activity after apple juice consumption in healthy subjects.

OBJECTIVE: To determine whether (1) rapid consumption of 1 L of apple juice increases blood antioxidant capacity, measured as ferric-reducing ability of plasma (FRAP) and serum 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, and (2) apple polyphenols or fructose-induced elevation of plasma uric acid contributes to post-juice increase of blood antioxidant activity. METHODS: The study involved 12 (mean age 32 ± 5 years, mean body weight 73 ± 7 kg) healthy nonsmoking subjects. Tested subjects consumed 1 L of clear apple juice and then FRAP; serum DPPH-scavenging activity, serum uric acid, and total plasma phenolics and quercetin levels were measured just before juice ingestion and 1, 2.5, and 4 hours after ingestion. This was repeated 3 times with 4-day intervals, but volunteers drank either 1 L of clear apple juice without polyphenols (placebo), or 1 L of cloudy apple juice (positive control), or 1 L of water (negative control) at the time. All juices had similar content of sugars (i.e., saccharose, glucose, and fructose) and precisely defined composition of phenolics and antioxidant activity. RESULTS: Consumption of all 3 juices transiently increased FRAP and serum DPPH-scavenging activity, with peak values at 1 hour post-juice ingestion. This was paralleled by the rise of serum uric acid, but no significant changes in plasma total phenolics and quercetin levels were observed after all dietary interventions. At the same time, no substantial differences were found between juices (especially between clear apple juice and clear apple juice without polyphenols) concerning the measured variables. A strong significant correlation was noted instead between serum uric acid and plasma antioxidant activity at all analyzed time points, before and after juice ingestion. Plasma total phenolics and quercetin levels were not associated with FRAP and serum DPPH radical-scavenging activity. CONCLUSIONS: We have demonstrated that rapid consumption of apple juice increased plasma antioxidant activity in healthy subjects; this was caused by the fructose-induced rise of serum uric acid levels, but was not due to the presence of antioxidant polyphenols in juice. Thus, short-term consumption of apple juice seems not to be the effective dietary intervention to augment plasma antioxidant activity due to the concomitant possibility for uric acid to be a risk factor for several diseases, as verified by other authors.

Ero1alpha is expressed on blood platelets in association with protein-disulfide isomerase and contributes to redox-controlled remodeling of alphaIIbbeta3.

Recent evidence supports a role of protein-disulfide isomerase (PDI) in redox-controlled remodeling of the exofacial domains of α(IIb)ß(3) in blood platelets. The aim of this study was to explain whether Ero1α can be responsible for extracellular reoxidation of the PDI active site. We showed that Ero1α can be found on platelets and is rapidly recruited to the cell surface in response to platelet agonists. It is physically associated with PDI and α(IIb)ß(3), as suggested by colocalization analysis in confocal microscopy and confirmed by immunoprecipitation experiments. Apart from monomeric oxidized Ero1α, anti-α(IIb)ß(3) immunoprecipitates showed the presence of several Ero1α-positive bands that corresponded to the complexes α(IIb)ß(3)-PDI-Ero1α, PDI-Ero1α, and Ero1α-Ero1α dimers. It binds more efficiently to the activated α(IIb)ß(3) conformer, and its interaction is inhibited by RGD peptides. Ero1α appears to be involved in the regulation of α(IIb)ß(3) receptor activity because of the following: (a) blocking the cell surface Ero1α by antibodies leads to a decrease in platelet aggregation in response to agonists and a decrease in fibrinogen and PAC-1 binding, and (b) transfection of MEG01 with Ero1α increases α(IIb)ß(3) receptor activity, as indicated by increased binding of fibrinogen.

Interaction and functional association of protein disulfide isomerase with alphaVbeta3 integrin on endothelial cells.

Adhesive properties of endothelial cells are influenced by the thioldisulfide balance. However, the molecular mechanism of this effect is unclear, although recent observations indicate that integrin receptors may be direct targets for redox modulation. The purpose of this study was to examine whether protein disulfide isomerase (PDI) is directly involved in this process. As manganese ions are known to affect the thioldisulfide balance and activate integrins to maximal affinity, we searched for PDI interactions with integrins, particularly with alpha(V)beta(3), in Mn(2+)-treated endothelial cells. By employing confocal microscopy, flow cytometry and coimmunoprecipitation experiments, we showed that exposure of endothelial cells to Mn(2+) resulted in: (a) the appearance of surface protein thiol groups, which can be found in PDI and alpha(V)beta(3), and both proteins colocalizing on the cellular surface; and (b) the formation of the PDI-alpha(V)beta(3) complex, which dissociates upon reduction. In addition, PDI in a complex with alpha(V)beta(3) induces conversion of the integrin to the ligand-competent high-affinity state, as evidenced by increased binding of vitronectin. The membrane-impermeable sulfhydryl blockers 3-N-maleimidylpropionyl biocytin 3-N-maleimidylpropionyl biocytin and p-chloromercuriphenyl sulfonate, as well as the PDI inhibitors bacitracin, MA3 018, and MA3 019, abolished the binding of vitronectin and LM609 to endothelial cells that is activated by Mn(2+). Consistently, LM609 almost completely blocked binding of vitronectin to such cells. The formation of the PDI-alpha(V)beta(3) stoichiometric complex was further demonstrated by surface plasmon resonance analysis, which showed that the initial reversible binding of PDI becomes irreversible in the presence of Mn(2+), probably mediated by disulfide bonds. Thus, we show that Mn(2+) simultaneously modulates the thiol isomerase activity of PDI that is bound to alpha(V)beta(3) and induces its transition to the ligand-competent state, suggesting an alternative mechanism of integrin regulation.