Low serum 25-hydroxyvitamin D is associated with increased risk of stress fracture during Royal Marine recruit training.

UNLABELLED: The aim of this study was to investigate vitamin D status and stress fracture risk during Royal Marine military training. Poor vitamin D status was associated with an increased risk of stress fracture. Vitamin D supplementation may help to reduce stress fracture risk in male military recruits with low vitamin D status. INTRODUCTION: Stress fracture is a common overuse injury in military recruits, including Royal Marine (RM) training in the UK. RM training is recognised as one of the most arduous basic training programmes in the world. Associations have been reported between serum 25-hydroxyvitamin D (25(OH)D) and risk of stress fracture, but the threshold of 25(OH)D for this effect remains unclear. We aimed to determine if serum 25(OH)D concentrations were associated with stress fracture risk during RM training. METHODS: We prospectively followed 1082 RM recruits (males aged 16-32 years) through the 32-week RM training programme. Troops started training between September and July. Height, body weight and aerobic fitness were assessed at week 1. Venous blood samples were drawn at weeks 1, 15 and 32. Serum samples were analysed for 25(OH)D and parathyroid hormone (PTH). RESULTS: Seventy-eight recruits (7.2 %) suffered a total of 92 stress fractures. Recruits with a baseline serum 25(OH)D concentration below 50 nmol L(-1) had a higher incidence of stress fracture than recruits with 25(OH)D concentration above this threshold (χ(2) (1) = 3.564, p = 0.042; odds ratio 1.6 (95 % confidence interval (CI) 1.0-2.6)). Baseline serum 25(OH)D varied from 47.0 ± 23.7 nmol L(-1) in February, to 97.3 ± 24.6 nmol L(-1) in July (overall mean 69.2 ± 29.2 nmol L(-1), n = 1016). There were weak inverse correlations between serum 25(OH)D and PTH concentrations at week 15 (r = -0.209, p < 0.001) and week 32 (r = -0.214, p < 0.001), but not at baseline. CONCLUSION: Baseline serum 25(OH)D concentration below 50 nmol L(-1) was associated with an increased risk of stress fracture. Further studies into the effects of vitamin D supplementation on stress fracture risk are certainly warranted.

Unstable insertion in the 5' flanking region of the cystatin B gene is the most common mutation in progressive myoclonus epilepsy type 1, EPM1.

Progressive myoclonus epilepsy type 1 (EPM1, also known as Unverricht-Lundborg disease) is an autosomal recessive disorder characterized by progressively worsening myoclonic jerks, frequent generalized tonic-clonic seizures, and a slowly progressive decline in cognition. Recently, two mutations in the cystatin B gene (also known as stefin B, STFB) mapping to 21q22.3 have been implicated in the EPM1 phenotype: a G-->C substitution in the last nucleotide of intron 1 that was predicted to cause a splicing defect in one family, and a C-->T substitution that would change an Arg codon (CGA) to a stop codon (TGA) at amino acid position 68, resulting in a truncated cystatin B protein in two other families. A fourth family showed undetectable amounts of STFB mRNA by northern blot analysis in an affected individual. We present haplotype and mutational analyses of our collection of 20 unrelated EPM1 patients and families from different ethnic groups. We identify four different mutations, the most common of which consists of an unstable approximately 600-900 bp insertion which is resistant to PCR amplification. This insertion maps to a 12-bp polymorphic tandem repeat located in the 5' flanking region of the STFB gene, in the region of the promoter. The size of the insertion varies between different EPM1 chromosomes sharing a common haplotype and a common origin, suggesting some level of meiotic instability over the course of many generations. This dynamic mutation, which appears distinct from conventional trinucleotide repeat expansions, may arise via a novel mechanism related to the instability of tandemly repeated sequences.

Predictive Value of Supraventricular Short Runs for New-Onset Atrial Fibrillation in Patients with Ischemic Stroke.

Background: The clinical importance of supraventricular run (SVR) is uncertain in the management of patients with previous cerebrovascular events. We aim to evaluate the role of SVRs in the development of future atrial fibrillation (AF) in patients diagnosed with ischemic stroke. Methods: We retrospectively evaluated patients who underwent 24-h Holter monitoring for the evaluation of possible AF after ischemic cerebrovascular events. The presence and duration of SVR were noted. Subsequent diagnosis of AF was searched in patients with sinus rhythm. Results: A total of 694 patients were included in the analysis. SVR was detected in 104 (14.9%) patients in the study group. Seventy-one (10.2%) patients were diagnosed with AF in the follow-up. SVRs were more prevalent among patients with AF (P < 0.001). The median atrial run duration was 5.96 (2.02-17.84) s in the AF absent group vs. 8.76 (3.78-17.62) s in the AF present group (P < 0.001). The best predictive cut-off duration of an atrial run was 8 s (sensitivity = 61.5% and specificity = 74.4%, Area Under Curve (AUC) = 0.708). Cox regression analysis showed that age (odds ratio [OR]: 1.03, 95% confidence interval [CI]: 1.00-1.060, P = 0.020), presence of short supraventricular run (OR: 2.53, 95% CI 1.40-4.57, P = 0.002), and left atrial diameter (OR: 1.13 95% CI: 1.07-1.19, P < 0.001) were the independent predictors of AF development in the follow-up. Conclusion: Age, left atrial diameter, and the presence of SVRs are associated with an increased risk of future AF after ischemic stroke. SVR duration may be an important parameter in risk stratification.

Changes in physical performance during British Army Junior Entry, British Army Standard Entry and Royal Air Force Basic Training.

INTRODUCTION: The purpose was to quantify physical performance in men and women during British Army Junior Entry (Army-JE), British Army Standard Entry (Army-SE) and Royal Air Force (RAF) basic training (BT). DESIGN: Prospective longitudinal study. METHODS: 381 participants ((339 men and 42 women) n=141 Army-JE, n=132 Army-SE, n=108 RAF) completed a 2 km run, medicine ball throw (MBT) and isometric mid-thigh pull (MTP), pre-BT and post-BT. To examine changes in pre-BT to post-BT physical test performance, for each course, paired Student t-test and Wilcoxon test were applied to normally and non-normally distributed data, respectively, with effect sizes reported as Cohen's D and with rank biserial correlations, respectively. A one-way between-subjects analysis of variance (ANOVA) (or Welch ANOVA for non-normally distributed data) compared performance between quartiles based on test performance pre-BT. Where the main tests statistic, p value and effect sizes identified likely effect of quartile, post hoc comparisons were made using Games-Howell tests with Tukey's p value. Data are presented as mean±SD, with statistical significance set at p<0.05. RESULTS: During BT, 2 km run time improved by 13±46 s (-2.1%±8.1%), 30±64 s (-4.8%±12.3%) and 24±27 s (-4.5%±5.1%) for Army-JE, Army-SE and RAF, respectively (all p<0.005). MBT distance increased by 0.27±0.28 m (6.8%±7.0%) for Army-JE (p<0.001) and 0.07±0.46 m (2.3%±10.9%) for Army-SE (p=0.040), but decreased by 0.08±0.27 m (-1.4%±6.0%) for RAF (p=0.002). MTP force increased by 80±281 n (10.8%±27.6%) for Army-JE (p<0.001) and did not change for Army-SE (-36±295 n, -0.7%±20.6%, p=0.144) or RAF (-9±208 n, 1.0±17.0, p=0.603). For all tests and cohorts, participants in the lowest quartile of pre-BT performance scores demonstrated greater improvements, compared with participants in the highest quartile (except Army-JE MBT, ∆% change similar between all quartiles). CONCLUSIONS: Changes in physical performance were observed for the three fitness tests following the different BT courses, and recruits with the lowest strength and aerobic fitness experienced greatest improvements.

Efficacy of protracted dose-dense temozolomide in patients with recurrent high-grade glioma.

The current standard therapy for newly diagnosed glioblastoma is multimodal, comprising surgical resection plus radiotherapy and concurrent temozolomide, then adjuvant temozolomide for 6 months. This has been shown to provide survival benefits; however, the prognosis for these patients remains poor, and most relapse. The objective of this prospective Phase II study was to evaluate the efficacy and tolerability of protracted, dose-dense temozolomide therapy (100 mg/m(2) for 21 consecutive days of a 28-day cycle) in patients with recurrent glioblastoma or grade 3 gliomas who had previously received standard therapy. Of the 25 patients included (median age 50 years), 20 were evaluable for radiologic response. Two patients had partial responses and 10 had stable disease (60% overall clinical benefit); 8 patients (40%) progressed after the first treatment cycle. Five patients were not assessed for radiologic response due to early clinical progression but were included in the progression-free survival (PFS) and overall survival (OS) analyses. The median follow-up time was 7 months (range, 1-14 months). The median PFS was 3 months (95% confidence interval, CI, 1.8-4.2) and the median OS was 7 months (95% CI 5.1-8.9). The 6-month PFS rate (primary endpoint) was 17.3% (95% CI 1.7-32.2) and the 1-year OS rate was 12% (95% CI -1-25). This regimen was well tolerated. The most frequent adverse event was lymphopenia (grade 3-4 in 20 patients); no opportunistic infections were reported. Treatment was discontinued due to toxicity in 2 patients (grade 4 hepatic toxicity and thrombocytopenia). These data suggest that protracted, dose-dense temozolomide had modest activity with manageable toxicity in patients with recurrent high-grade glioma previously treated with temozolomide.

Can Hyperpolarized Helium MRI add to radiation planning and follow-up in lung cancer?

Locally advanced non-small-cell lung cancer (NSCLC) is a common disease with a low overall survival even with aggressive treatments. Standard imaging (CT and PET/CT) provide no information about normal lung function. We therefore, sought to pilot HeMRI in patients with non-small-cell lung cancer before and after definitive radiotherapy (RT). Five patients with NSCLC receiving RT were enrolled on a prospective IRB approved study. Patients underwent CT, FDG-PET and HeMRI before and (within 10 days) following RT. All images (CT, FDG-PET and HeMRI) were co-registered. The CT and PET GTVs were contoured, as well as the ventilation defects on HeMRI caused by the tumor. Patients also underwent pulmonary function tests (PFTs). Correlations between the images and PFTs were evaluated by linear regression. CT and FDG-PET tumor volumes were highly correlated (r² = 0.91 before treatment and 0.99 following RT). There was less correlation between HeMRI and CT or PET (r² = 0.67 (CT) and 0.38 (PET)) prior to treatment and 0.27 following RT). However, HeMRI volumes correlated very well with FEV1, both prior to and following RT. (r² = 0.89 and 0.83, respectively). ³Helium MRI scanning is feasible in NSCLC before and after treatment. HeMRI provides important functional information in addition to CT and CT/PET scanning.

Distinct lines of chickens express different splenic cytokine profiles in response to Salmonella Enteritidis challenge.

Chicken meat and eggs contaminated with Salmonella result in economic losses in the poultry industry and potential human infection. Intestinal parasites have been shown to lead to a reduction in the utilization of nutrients and performance in poultry. This study provides insight into the immune responses used by hens of 3 genetically distinct chicken lines (broiler, Leghorn, and Fayoumi) in the presence and absence of Salmonella Enteritidis infection. Understanding the range of immune responses used by different lines in response to Salmonella Enteritidis may help the poultry industry genetically select birds that are more pathogen resistant. The splenic mRNA levels of several immune-related genes [IL-6, IL-8, IL-10, IL-18, macrophage inflammatory protein 1ß, interferon (IFN)-γ, transforming growth factor ß1, and regulated upon activation, normal T cell expressed, and secreted (RANTES)] were analyzed by quantitative PCR. Line, challenge, and their interaction were considered fixed effects. Line had a significant effect on the mRNA expression of RANTES (P < 0.02) and IFN-γ (P < 0.03). Broilers expressed significantly more splenic RANTES mRNA than Fayoumis, and significantly more splenic IFN-γ mRNA than Leghorns (P < 0.05). There was a significant interaction of genetic line and challenge on IL-18 (P < 0.02) and IL-6 (P < 0.01) mRNA expression. Although there was a significant interaction of genetic line and challenge for IL-18, Tukey's test analysis only showed differences at a suggestive level (P < 0.1). Bacterial challenge had a significant effect on IL-6 mRNA expression only within the Fayoumi line. Challenged Fayoumis expressed significantly less IL-6 mRNA than nonchallenged Fayoumis (P < 0.05). The observed differences in mRNA expression of selected cytokines support the concept that these distinct genetic lines utilize different immune responses at homeostasis and in response to Salmonella Enteritidis infection.

Cation currents in human airway epithelial cells induced by infection with influenza A virus.

Influenza A viruses cause lung disease via an incompletely understood mechanism that involves the accumulation of liquid within the lungs. The accumulation of lung liquid is normally prevented by epithelial Na(+) absorption, a transport process regulated via several pathways including phosphoinositide-3-kinase (PI3K). Since the influenza A virus encodes a non-structural protein (NS1) that can activate this kinase, we now explore the effects of NS1 upon the biophysical properties of human airway epithelial cells. Transient expression of NS1 depolarized electrically isolated cells maintained in glucocorticoid-free medium by activating a cation conductance identical to the glucocorticoid-induced conductance seen in single cells. This response involved PI3K-independent and PI3K-dependent mechanisms. Infecting glucocorticoid-deprived cells with influenza A virus disrupted the normal electrical coupling between neighbouring cells, but also activated a conductance identical to that induced by NS1. This response to virus infection was only partially dependent upon NS1-mediated activation of PI3K. The presence of NS1 allows influenza A to modify the biophysical properties of infected cells by activating a Na(+)-permeable conductance. Whilst the activation of Na(+)-permeable channels may be expected to increase the rate of Na(+) absorption and thus reduce the volume of liquid in the lung, liquid does normally accumulate in influenza A-infected lungs. The overall effect of influenza A on lung liquid volume may therefore reflect a balance between the activation and inhibition of Na(+)-permeable channels.

Contrasting gender differences on two measures of exercise dependence.

OBJECTIVE: Recent studies using multidimensional measures have shown that men (Exercise Dependence Scale; EDS-R) are more exercise-dependent than women, whereas others have found that women (Exercise Dependence Questionnaire; EDQ) are more exercise-dependent than men. This study investigated whether there may be sex differences in exercise dependence or whether the questionnaires may be measuring different dimensions of exercise dependence. DESIGN: Regular exercisers voluntarily completed the EDS-R, EDQ and Drive for Thinness (DFT) subscale before or after a workout. SETTING: A local health club in the eastern USA. PARTICIPANTS: Male (n = 102) and female (n = 102) exercisers completed the three questionnaires, but 11 participants (1 man, 10 women) were excluded from further analysis because scores indicated possible secondary exercise dependence (eating disorder). PRIMARY OUTCOME MEASURES: Eight subscales of the EDQ, seven subscales of the EDS, the DFT subscale, and several demographic variables served as dependent measures. RESULTS: A multivariate analysis of variance (MANOVA) on the EDS-R showed that men were significantly higher than women on the Withdrawal, Continuance, Tolerance, Lack of Control, Time, and Intention Effect subscales. Another MANOVA on the EDQ indicated that women scored significantly higher than did men on the Interference, Positive Rewards, Withdrawal, and Social Reasons subscales. Statistical analysis using t tests revealed that men had significantly higher total EDS-R scores than women, but women had significantly higher EDQ and DFT scores. CONCLUSION: These results suggest that both questionnaires measure different aspects of exercise dependence that favour either gender. It remains for further research to determine whether these instruments are equally viable for measurement of ED in both men and women.

Abscopal Effect of Radiotherapy in the Immunotherapy Era: Systematic Review of Reported Cases.

Mounting evidence suggests that radiation stimulates the immune system and this contributes to the abscopal effect, which is defined as "response at a distance from the irradiated volume." Though identified more than 50 years ago, the abscopal effect is revisited today. One rationale is that the abscopal effect is often observed with efficient immunotherapy. Here, we give an overview of the clinical data on the abscopal effect, generated by a combination of immunotherapy and radiotherapy (RT). Only papers that included RT in combination with immunotherapy were evaluated according to four main categories including RT parameters, sequencing of therapies, the definition of the abscopal effect, and patient selection. Twenty-four cases in 15 reports were reviewed. The results varied. Patient ages ranged from 24 to 74. RT dose (median total dose 18-58 Gy) varied. Biologically effective dose (BED) 10 was calculated to be a median 49.65 Gy (28-151 Gy). The time to a documented abscopal response ranged from less than a month to 12 months. The large variation concerning fractionation and sequencing of therapies indicates that these conflicting points need to be resolved, to generate for the abscopal effect to be clinically significant.

1.5mile run time and body mass predict 8mile loaded march performance, irrespective of sex.

OBJECTIVES: To develop a statistical model to predict 8mile Loaded March (LM) performance and quantify differences in physical characteristics for men and women British Army Personnel. DESIGN: 135 trained soldiers (87 men; 48 women) completed two sessions, seven days apart. METHODS: Session 1: Participants' stature, body mass, Fat Free Mass (FFM) [by dual-energy X-ray absorptiometry], Single Lift (SL), Water Can Carry (WCC), and 1.5mile run performance were measured. Session 2: Participants completed an 8mile LM, carrying 25kg (4miles paced and 4miles individual best effort). Sex differences were compared using independent samples t-tests and 8mile LM performance time was predicted using various multiple linear regression analysis: hierarchical forced entry multiple ordinary least squares, principal component and ordinary least products. RESULTS: A combination of 1.5mile run time and body mass were the strongest predictors of 8mile LM time (R2=0.71; SEE=4.17min; p<0.001). Including stature, FFM, sex, SL score, or WCC score did not further improve predictions (p>0.05). Compared to women, men had faster mean 1.5mile run and LM times, greater body mass and total FFM and higher SL and WCC scores (p<0.001), however some women outperformed men. CONCLUSION: 1.5mile run time and body mass predict 8mile LM performance with no further improvement gained in the model by including sex as a variable.

Characterizing the acute heat stress response in gilts: I. Thermoregulatory and production variables.

Identifying traits associated with susceptibility or tolerance to heat stress (HS) is a prerequisite for developing strategies to improve efficient pork production during the summer months. Study objectives were to determine the relationship between the thermoregulatory and production responses to acute HS in pigs. Prepubertal gilts (n = 235; 77.9 ± 1.2 kg BW) were exposed to a thermoneutral (TN) period (P1, 24 h; 21.9 ± 0.5 °C, 62 ± 13% RH; fed ad libitum) followed immediately by a subsequent acute HS period (P2, 24 h; 29.7 ± 1.3 °C, 49 ± 8% RH; fed ad libitum). Rectal temperature (TR), skin temperature (TS), and respiration rate (RR) were monitored and BW and feed intake (FI) were determined. All pigs had increased TR, TS, and RR (0.80 °C, 5.65 °C, and 61.2 bpm, respectively; P < 0.01) and decreased FI and BW (29% and 1.10 kg, respectively; P < 0.01) during P2 compared to P1. Interestingly, body temperature indices did not explain variation in FI during P2 (R2 ≤ 0.02). Further, the percent change in BW during P2 was only marginally explained by each body temperature index (R2 ≤ 0.06) or percent change in FI (R2 = 0.14). During HS, TR was strongly correlated with P1 TR (r = 0.72, P < 0.01), indicating a pig's body temperature during TN conditions predicts the severity of hyperthermia during HS. Additionally, the change in TR (ΔTR, HS TR - TN TR) was larger in pigs retrospectively classified as susceptible (SUS) as compared to tolerant (TOL) pigs (1.05 vs. 0.51 °C, respectively; P < 0.01). In summary, thermoregulatory responses and production variables during acute HS are only marginally related. Further, changes in BW and FI were unexpectedly poorly correlated during acute HS (r = 0.34; P < 0.01). Collectively, suboptimal growth is largely independent on the thermoregulatory response and hypophagia during acute HS. Consequently, incorporating solely body temperature indices into a genetic index is likely insufficient for substantial progress in selecting HS tolerant pigs.

Intensity-modulated radiotherapy for head and neck cancer.

Intensity-modulated radiation therapy (IMRT) is a new radiation delivery technique that allows more precise delivery of radiation and optimization of the dose intensity to specific volumes while sparing the dose to critical normal structures. Using IMRT in head and neck cancers is attractive because of close proximity of the tumor targets to critical normal structures such as the spine, eyes, and parotid glands. IMRT has been shown in a number of clinical sites to improve local control and decrease side effects. Specifically, IMRT has shown the ability to preserve salivary function through sparing of the parotid glands. At the same time, there remain some uncertainties in terms of target delineation, secondary cancers, and side effects to swallowing function that may be increased with IMRT. Multi-institutional studies of IMRT are under way, and these studies, combined with refinements of the technique, should lead to continued improvement in the radiotherapeutic management of head and neck cancer.

The effects of antioxidants in the senescent auditory cortex.

We investigated whether a 2-month dietary supplementation of antioxidants, in the form of blueberry phytochemicals, could reverse or retard the age-related decline in temporal processing speed observed in the aged rat. To this end, extracellular single unit responses to frequency modulated (FM) sweeps were recorded in the primary auditory cortex (AI) of aged rats that had been placed on either a blueberry-supplemented or control diet 2 months prior to the physiological recordings. Results showed that most cells recorded from the blueberry-fed rats responded most vigorously to fast FM sweeps, similar to that observed in young rats. In contrast, the majority of cells recorded from the control rats showed a preference for slow FM sweep rates. These results suggest that age-related changes in temporal processing speed in A1 may be reversed by dietary supplementation of blueberry phytochemicals.

Short message service (SMS) texting as a method of communication during on call: prevalence and experience of medical staff in a large acute NHS Trust in the UK.

With the widespread use of smartphones, text messaging has become an accepted form of communication for both social and professional use in medicine. To our knowledge no published studies have assessed the prevalence and use of short message service (SMS) texting by doctors on call. We have used an online questionnaire to seek information from doctors in a large NHS Trust in the UK about their use of texting while on call, what they use it for, and whether they send images relevant to patients' care. We received 302 responses (43% response rate), of whom 166 (55%) used SMS while on call. There was a significant association between SMS and age group (p=0.005), with the 20-30-year-old group using it much more than the other age groups. Doctors in the surgical specialties used it significantly less than those in other speciality groups (p<0 .001). Texting while on call was deemed to be safe and reliable (p<0.001). Eighteen clinicians (11%) admitted to routinely sending images of patients by text, despite some being identifiable. Texting was mainly used to update colleagues on patients' progress and give information about times of ward rounds and meetings. With the increasing use of texting in healthcare, much of which seems to be unregulated, further work and detailed guidance is required on what information may be given to ensure confidentiality and that SMS is a safe and acceptable method of communication to use when on call.

Reversals of age-related declines in neuronal signal transduction, cognitive, and motor behavioral deficits with blueberry, spinach, or strawberry dietary supplementation.

Ample research indicates that age-related neuronal-behavioral decrements are the result of oxidative stress that may be ameliorated by antioxidants. Our previous study had shown that rats given dietary supplements of fruit and vegetable extracts with high antioxidant activity for 8 months beginning at 6 months of age retarded age-related declines in neuronal and cognitive function. The present study showed that such supplements (strawberry, spinach, or blueberry at 14.8, 9.1, or 18.6 gm of dried aqueous extract per kilogram of diet, respectively) fed for 8 weeks to 19-month-old Fischer 344 rats were also effective in reversing age-related deficits in several neuronal and behavioral parameters including: oxotremorine enhancement of K(+)-evoked release of dopamine from striatal slices, carbachol-stimulated GTPase activity, striatal Ca(45) buffering in striatal synaptosomes, motor behavioral performance on the rod walking and accelerod tasks, and Morris water maze performance. These findings suggest that, in addition to their known beneficial effects on cancer and heart disease, phytochemicals present in antioxidant-rich foods may be beneficial in reversing the course of neuronal and behavioral aging.

Polyphenolics enhance red blood cell resistance to oxidative stress: in vitro and in vivo.

In this study we investigated the potential antioxidant properties of blueberry polyphenolics in vitro and vivo, using red blood cell (RBC) resistance to reactive oxygen species (ROS) as the model. In vitro incubation with anthocyanins or hydroxycinnamic acids (HCA) (0.5 and 0.05 mg/ml) was found to enhance significantly RBC resistance to H2O2 (100 microM) induced ROS production. This protection was also observed in vivo following oral supplementation to rats at 100 mg/ml. However, only anthocyanins were found to afford protection at a significant level, this at 6 and 24 h post supplementation. This protection was not consistent with the measured plasma levels of anthocyanins. Indeed, plasma polyphenolic concentrations were highest after 1 h, declining considerably after 6 h and not detected after 24 h. The difference in absorption between anthocyanins and HCA is likely to have contributed to the observed difference in their abilities to afford protection to RBC. This protection represents a positive role following dietary consumption of polyphenolics from blueberries, against ROS formation within RBC in vivo.

Amelioration of Ozone-Induced Oxidative Damage in Wheat Plants Grown under High Carbon Dioxide (Role of Antioxidant Enzymes).

O3-induced changes in growth, oxidative damage to protein, and specific activities of certain antioxidant enzymes were investigated in wheat plants (Triticum aestivum L. cv Roblin) grown under ambient or high CO2. High CO2 enhanced shoot biomass of wheat plants, whereas O3 exposure decreased shoot biomass. The shoot biomass was relatively unaffected in plants grown under a combination of high CO2 and O3. O3 exposure under ambient CO2 decreased photosynthetic pigments, soluble proteins, and ribulose-1,5-bisphosphate carboxylase/oxygenase protein and enhanced oxidative damage to proteins, but these effects were not observed in plants exposed to O3 under high CO2. O3 exposure initially enhanced the specific activities of superoxide dismutase, peroxidase, glutathione reductase, and ascorbate peroxidase irrespective of growth in ambient or high CO2. However, the specific activities decreased in plants with prolonged exposure to O3 under ambient CO2 but not in plants exposed to O3 under high CO2. Native gels revealed preferential changes in the isoform composition of superoxide dismutase, peroxidases, and ascorbate peroxidase of plants grown under a combination of high CO2 and O3. Furthermore, growth under high CO2 and O3 led to the synthesis of one new isoform of glutathione reductase. This could explain why plants grown under a combination of high CO2 and O3 are capable of resisting O3-induced damage to growth and proteins compared to plants exposed to O3 under ambient CO2.

The effect of pharmacologically altered gastric pH on cadmium absorption from the diet and its accumulation in murine tissues.

Solubility of Cd in Cd-amended mouse chow in water was reduced by increased pH; even less Cd was solubilized by simulated digestion in vitro, where increased gastric phase pH decreased solubility, an effect that persisted following intestinal digestion at pH 5.5. These data suggested that increasing gastric pH in vivo pharmacologically would reduce Cd accumulation in target organs of mice treated with omeprazole (a proton-pump inhibitor) or cimetidine (a H2-receptor antagonist). This expectation was mostly not realized. Gastric pH in animals receiving Cd-amended diet was increased by omeprazole, but not cimetidine, relative to animals receiving no drugs, and Cd-amended diet. Tissue concentrations of Cd were similar among the three groups receiving Cd-amended diet, for liver, kidney and testes. Small intestine Cd concentration was lower for omeprazole-treated animals than for those receiving neither drug and Cd-amended diet, suggesting that omeprazole decreased Cd absorption by this organ. This effect may have been compensated for by increased uptake of complexed Cd by the large intestine, as accumulation in the liver, kidney and testes was not reduced. In vitro determinations of bioaccessible Cd in food may not predict in vivo bioaccumulation in all target organs.