Spatial and temporal analysis of the risks posed by metal contamination in coastal and marine sediments of Bahrain.

Nine metals including Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were analysed from sediment samples collected from 29 stations since 2007 from Bahraini waters. Within this study, it was investigated whether concentrations of these determinants are at concentrations above internationally established Assessment Criteria (AC). The majority of sites were considered not to pose a toxicological risk in terms of metal contamination. Where breaches occurred, they were mainly from historic samples related to Cr, Cu and Ni contamination. A trend assessment revealed that out of 59 significant trends, 36 were downwards and 23 upwards, indicating that some determinants like Al, Zn and Ni are improving strongly across some sites, whilst areas associated with industrial activity still see some increasing trends for Al, Cd, Pb and Zn.

At-vessel mortality of skates (Rajidae) taken in coastal fisheries and evidence of longer-term survival.

Data on the vigour and at-vessel mortality (AVM) of 6798 skates (comprising Raja clavata n = 6295; R. brachyura n = 208; R. undulata n = 185, R. montagui n = 98 and R. microocellata n = 12) captured by commercial fishing vessels in the inshore waters of the southern North Sea and English Channel were recorded. AVM in longline fisheries averaged 0·44% across five vessels (0-1·47%), although skates were usually unhooked manually and did not usually pass through a bait-stripper. AVM in otter trawls averaged 0·76% (0-2·35%), from four vessels fishing with tow durations of <1·5 h (southern North Sea) or 1-4 h (English Channel). No AVM was noted for skates taken as a by-catch in drift trammel nets (soak times <4 h). Anchored tangle nets resulted in an overall AVM of 2·0-2·7%, but increased from 1·47% (13-28 h soak time) to 6·16% (42-53 h soak time). There were significant differences in the vigour of skates between gears, with R. clavata caught by longline and tangle nets in better condition than those captured by otter trawl or drift trammel net. Similarly, R. undulata caught by tangle net were in better condition than those caught by otter trawl. The vigour of R. undulata was also found to be higher than other skate species for both trawl and tangle net. In total, 5283 skates were tagged with Petersen discs and released, with recapture rates for the various combinations of vessel and gear ranging up to 24·8% for R. clavata. Whilst confirming a degree of post-release survival, quantitative estimates of post-release mortality for skates remain unknown.

Development of schooling behaviour during the downstream migration of Atlantic salmon Salmo salar smolts in a chalk stream.

The downstream migratory behaviour of wild Atlantic salmon Salmo salar smolts was monitored using passive integrated transponder (PIT) antennae systems over 10 years in the lower reaches of a small chalk stream in southern England, U.K. The timing of smolt movements and the likely occurrence of schooling were investigated and compared to previous studies. In nine of the 10 consecutive years of study, the observed diel downstream patterns of S. salar smolt migration appeared to be synchronized with the onset of darkness. The distribution of time intervals between successive nocturnal detections of PIT-tagged smolts was as expected if generated randomly from observed hourly rates. There were, however, significantly more short intervals than expected for smolts detected migrating during the day. For each year from 2006 to 2011, the observed 10th percentile of the daytime intervals was <4 s, compared to ≥55 s for the simulated random times, indicating greater incidence of groups of smolts. Groups with the shortest time intervals between successive PIT tag detections originated from numerous parr tagging sites (used as a proxy for relatedness). The results suggest that the ecological drivers influencing daily smolt movements in the lower reaches of chalk stream catchments are similar to those previously reported at the onset of migration for smolts leaving their natal tributaries; that smolts detected migrating during the night are moving independently following initiation by a common environmental factor (presumably darkness), whereas those detected migrating during the day often move in groups, and that such schools may not be site (kin)-structured. The importance of understanding smolt migratory behaviour is considered with reference to stock monitoring programmes and enhancing downstream passage past barriers.

Comparison of steer behavior when housed in a deep-bedded hoop barn versus an open feedlot with shelter.

The use of hoop barns as an alternative housing system for beef cattle has not been widely researched. The objectives of this study were to determine the main effects of behavior of steers 1) over winter and summer, 2) when housed in either a hoop barn or a conventional feedlot, and 3) interactions between season and housing system. A total of 960 crossbred Bos taurus steers were used [August 2006 to April 2008 (2 winter and 2 summer trials)]. Steers were housed in either 1 deep-bedded hoop barn (n = 12 pens; 4.65 m(2)/steer) or 1 open feedlot with shelter (n = 12 pens; 14.7 m(2)/steer). Steers were ear tagged, implanted, and weighed (414 ± 36 kg) on arrival and allotted to treatments that were balanced for source, BW, and hide color. Behavioral data (3 postures and 2 behaviors) were collected using a 10-min live scan. The experimental unit for behavior was a pen of steers. Behavioral data were arcsine transformed to achieve a normal distribution. There were no (P > 0.05) differences for time spent at bunk or waterer for steers between housing treatments. Steers housed in an open feedlot with shelter spent less time lying and more time standing and walking (P < 0.05) compared with steers housed in a hoop barn. There were no (P = 0.32) differences between seasons for standing. Steers spent more time at the bunk (P < 0.0001) and waterer (P < 0.0001) in the summer compared with the winter. In the winter, steers engaged in more lying (P = 0.0002) and walking (P < 0.0001). Overall, steers stood less (P = 0.006) and spent more time lying (P = 0.024) when housed in a hoop barn than in the open feedlot with shelter regardless of season. Steers housed in the open feedlot with shelter walked more (P < 0.0001) than steers housed in the hoop barn and walked more (P < 0.0001) in winter than in summer months (6 vs. 3%). There were no (P > 0.05) differences in time spent at bunk and waterer between housing systems within season, but time spent at the waterer and bunk decreased (P < 0.05) for both housing systems during the winter. In conclusion, housing 40 steers per pen in a cornstalk-bedded hoop barn at 4.65 m(2)/steer does not result in adverse behavioral alterations and can be considered as a housing alternative for finishing steers in the Midwestern United States when compared with steers fed in an open feedlot with shelter provided.

Performance and carcass characteristics of finishing beef cattle managed in a bedded hoop-barn system.

The use of bedded hoop barns in finishing systems for beef cattle has not been widely researched. In this management system, beef cattle are confined to hoop barns throughout finishing, and bedding is used to absorb animal waste, which results in minimal effluent. The objective of this study was to compare the performance and carcass characteristics of finishing beef steers (n = 1,428) managed in a bedded hoop-barn management system vs. an open-feedlot system with shelter. Six feeding trials were conducted over a 3-yr period. Three trials were conducted during summer-fall and 3 trials were conducted during winter-spring. Crossbred steers were allotted to 3 pens in the hoop-barn system and to 3 pens in the open-lot system (approximately 40 steers per pen in both facility systems). Stocking densities for the steers were 4.65 m(2) per steer in the hoop-barn system and 14.7 m(2) per steer in the open-lot system. The steers were begun on trial weighing 410 and 411 kg (SD = 21), were fed for 102.3 and 103.0 d (SD = 3.8), and were weighed off test at 595 and 602 kg (SD = 21) for the hoop-barn and open-lot systems, respectively. Steer performance measures consisted of ADG, DMI, and G:F. Carcass characteristics were HCW, fat thickness, LM area, KPH percentage, marbling score, USDA yield grade, and USDA quality grade. No year, season, or pen (management system) main effects, or season x management system and year x management system interactions were observed for any of the items measured related to cattle performance or carcass characteristics (P > 0.05). Final mud scores (a subjective evaluation of the amount of soil and manure adhering to the hair coat of the animals) were greater for the steers from the open-lot system compared with those from the hoop-barn system (P < 0.02), suggesting steers in the hoop-barn system carried less mud than steers from the open-lot system. Average daily cornstalk bedding use in the hoop-barn system was 2.3 kg/steer during summer-fall and 2.6 kg/steer during winter-spring. The performance of finishing cattle managed in a hoop-barn system was not different from the performance of cattle managed in an open-feedlot system with shelter during summer and winter. Managing beef cattle in hoop barns required more bedding but resulted in decreased mud scores compared with cattle managed in an open-lot system with shelter. Hoop barns are a viable alternative housing management system for finishing beef cattle.

Effects of Water Stress on Colonization of Poplar Stems and Excised Leaf Disks by Septoria musiva.

ABSTRACT Septoria musiva causes leaf spot and canker diseases of trees in the genus Populus, and is one of the most damaging fungal pathogens of hybrid poplar in eastern North America. The effect of host water stress on Septoria canker development was studied in two separate greenhouse experiments. Hybrid poplar clones NM6, NC11396, and NE308 were stressed by withholding water until predawn water potential fell below -1.0 MPa. Stems were treated by removing a leaf and applying agar plugs that were either colonized by S. musiva (inoculated) or sterile (control) to the wound. Cankers on inoculated water-stressed trees were significantly larger than those on nonstressed trees. A leaf disk assay also was conducted three times with the NM6 and NE308 trees. We cut two disks from each of 120 stressed and 120 well-watered trees, placing them on water agar in 24-well tissue culture plates. A conidial suspension was applied to one disk in each pair and sterile water to the other. Inoculated disks from water-stressed trees developed less necrosis than those from well-watered trees. These results demonstrate that environmental influences on host condition must be considered in evaluating resistance of clones proposed for widespread culture of hybrid poplar.

Subcellular distribution and immunocytochemical localization of Na,K-ATPase subunit isoforms in human skeletal muscle.

The expression of Na,K-ATPase isoforms was investigated in human skeletal muscle membranes isolated by subcellular fractionation. The alpha 1, alpha 2, alpha 3 and beta 1 subunits were detectable in membranes prepared from the human soleus muscle. The alpha 1 subunit was largely detected in a fraction enriched with plasma membranes (PM), its abundance in an intracellular membrane fraction (IM) accounted for only 4% of that in the PM fraction. No alpha 1 subunits were detected in membranes of sarcoplasmic reticulum (SR) origin. The PM and IM fractions were enriched with alpha 2 subunits which were less abundant in the SR-enriched fraction. The abundance of alpha 2 molecules within the IM fraction was about 75% of that in the PM fraction when the total protein content for the two fractions was taken into account. Immunocytochemical studies confirmed the localization of the alpha 1 subunit to the muscle cell surface. The alpha 2 subunit was also found to be present in the cell surface but the observation that alpha 2 immunofluorescence was diffusely dispersed throughout the muscle fibre indicated that it was also present intracellularly, consistent with its biochemical localization in the PM and IM membrane fractions. The alpha 3 subunit was detected largely in the PM fraction but the lack of good antibodies to this isoform precluded an analysis of its immunocytochemical localization. The beta 1 subunit was enriched in the PM fraction but was also detected to a modest extent in the IM.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhaled nedocromil sodium reduces histamine release from isolated large airway segments of asthmatic subjects in vivo.

Placement of an intrabronchial single balloon catheter provides the possibility of measuring histamine release in isolated large airway segments in vivo. We wanted to assess the protective effect of nedocromil sodium on intrabronchial histamine release after hyperosmolar challenge. Six mild asthmatics were bronchoscoped 30 min after inhalation of 4 mg nedocromil sodium or placebo, given via a metered dose inhaler in a randomized, double-blind, cross-over study. Lavage of the left main bronchus was carried out proximal to a balloon catheter inflated at its bifurcation, and specimens were assayed for histamine and prostaglandin D2 (PGD2) by radioimmunoassay. The rise in histamine concentration in bronchial epithelial fluid following hyperosmolar saline challenge was significantly greater following placebo than following nedocromil sodium (mean +/- SEM prechallenge histamine concentration on placebo day 6.9 +/- 2.9 nM; post-challenge: 25.3 +/- 8.0 nM; mean +/- SEM prechallenge histamine concentration on the day nedocromil sodium was given: 3.7 +/- 0.7 nM; post-challenge 5.8 +/- 1.7 nM). Changes in PGD2 levels reflected the changes in histamine, but the variability of response was large, and there were no significant differences between the effects of placebo and nedocromil sodium. The procedure caused significantly greater falls in peak expiratory flow rates following placebo (mean +/- SEM percentage fall 20.2 +/- 4.4%) than following nedocromil sodium (0.9 +/- 5.8%, p < 0.02). We conclude that there is tonic basal histamine release within asthmatic airways, and that nedocromil sodium inhibits histamine release from mediator cells in vivo.

Glutamine transport in human skeletal muscle.

Sarcolemmal vesicles isolated from human skeletal muscle obtained at surgery showed approximately 14-fold enrichment of sarcolemmal marker enzymes 5'-nucleotidase and K-stimulated phosphatase. [3H]glutamine transport in these vesicles was stereospecific, largely Na dependent, and tolerated Li-for-Na substitution. Glutamine transport was stimulated by an inside negative membrane potential, and 25 mM glutamine stimulated 22Na (0.1 mM) uptake into vesicles by 50%, indicating rheogenic cotransport of Na and glutamine. Alanine transport was Na dependent but did not tolerate Li-for-Na substitution. Transport of L-[3H]glutamine was inhibited by 35-65% with a 20-fold excess of glutamine, asparagine, and alanine; cysteine, alpha-(methylamino)isobutyrate, and 2-amino-2-norborane carboxylic acid had smaller inhibitory effects, although cysteine had an unusually large inhibitory effect on glutamine transport at 1,000-fold excess compared with most other amino acids. Glutamine transport showed sensitivity to pH values < 7.0. Glutamine transport consisted of a Na-dependent and a Na-independent component, both of which appeared saturable. The kinetic characteristics of the Na-dependent component were different in different types of muscles, with half-maximal concentrations (mM) varying from 1.6 +/- 0.4 (tibialis anterior) to 0.56 +/- 0.0.2 (gluteus maximus) and maximal velocity (pmol.mg protein-1.s-1) of 1.3 +/- 0.27 to 5 +/- 1.25 in the same muscles. The results demonstrate both marked similarities and important differences between the principal glutamine transporter in human skeletal muscle and the known system Nm transporter in rat skeletal muscle.

Compensatory growth in fibrotic lung injury.

We induced severe left-sided lung fibrosis by the unilateral endobronchial instillation of paraquat (1.0 mg/kg) into the left lungs of adult Fischer 344 male rats. Growth of the contralateral lung as well as its proliferative activity were measured 6 or 14 days later. Whereas the left lung underwent severe fibrosis and shrinkage with more than 85% reduction in lung volume, the right lung more than doubled in size. In addition, there was a significant increase in total protein content, DNA content, and DNA synthesis. We conclude that unilateral lung injury resulting in ipsilateral fibrosis and loss of parenchyma is associated with compensatory growth of the contralateral lung.

Skin responses to intradermal histamine and leukotrienes C4, D4, and E4 in patients with chronic idiopathic urticaria and in normal subjects.

Mast cell inflammatory mediators, such as histamine, and newly formed compounds, such as the leukotrienes, cause wheal and flare when they are injected intradermally into normal subjects and may therefore play a role in the formation of urticaria. The effects of intradermal injections (50 microliters) of six different concentrations of histamine (range, 3.3 x 10(-4) to 3.3 x 10(-9) mol/L) and the leukotrienes C4, D4, and E4 (range, 2 x 10(-4) to 2 x 10(-9) mol/L) have been compared in 10 normal subjects and in 10 patients with chronic idiopathic urticaria. Wheal-and-flare sizes were measured at timed intervals up to 4 hours, and area under the curve for each response over time was calculated. There were no significant differences in leukotriene-induced responses between groups. Maximum sizes of histamine-induced wheal and flare were similar in each group of subjects. There were, however, significant increases in mean areas under the response curve of histamine wheal and flare in the patients with urticaria (wheal, p less than 0.001; flare, p less than 0.001; analysis of variance). These findings demonstrate a prolongation of skin responses to histamine in patients with urticaria and suggest an impaired clearance of histamine (or other vasoactive agents released by histamine) from the skin of these patients.

Adverse effects of inhaled corticosteroids.

Corticosteroids have a significant role in the management of asthma due to their powerful anti-inflammatory actions. However, when given orally, they cause significant and unwanted side-effects. Early attempts to circumvent these side-effects were largely unsuccessful. Recently, new synthetic corticosteroids have been developed that have powerful topical action but weak generalised effects due to rapid systemic metabolism. These new compounds provide adequate control of airways' obstruction in almost all asthmatics. Oral candidiasis may occur but can generally be controlled by adjusting the frequency of dosage and changing delivery systems. In high doses, there is biochemical evidence of adrenal suppression, but the clinical importance of this is not yet clear and there is no evidence of a significant effect on growth in children. High dose inhaled corticosteroids have been shown to affect biochemical indices of bone turnover in the short term. The long term clinical consequences of this are still under evaluation. Inhaled corticosteroids have provided a significant advance in the management of asthma, but physicians need to remain alert for the possibility of systemic side effects when used in high doses for long periods of time.

Ventilatory effects of substance P, vasoactive intestinal peptide, and nitroprusside in humans.

Animal studies suggest that the neuropeptides, substance P and vasoactive intestinal peptide (VIP), may influence carotid body chemoreceptor activity and that substance P may take part in the carotid body response to hypoxia. The effects of these peptides on resting ventilation and on ventilatory responses to hypoxia and to hypercapnia have been investigated in six normal humans. Infusions of substance P (1 pmol.kg-1.min-1) and of VIP (6 pmol.kg-1.min-1) were compared with placebo and with nitroprusside (5 micrograms.kg-1.min-1) as a control for the hypotensive action of the peptides. Both peptides caused significantly less hypotension than nitroprusside. Substance P and nitroprusside caused significantly greater increases in ventilation and in the hypoxic ventilatory response than VIP. No changes were seen in hypercapnic sensitivity. The stimulation of ventilation and the differential effects on ventilatory chemosensitivity that accompanied hypotension are consistent either with stimulation of carotid body chemoreceptor activity or with an interaction with peripheral chemoreceptor input to the respiratory center, as is seen in animals. The similar cardiovascular but different ventilatory effects of the peptides suggest that substance P may also stimulate the carotid body in a manner independent of the effect of hypotension. This is consistent with a role of substance P in the hypoxic ventilatory response in humans.

Atrial natriuretic peptide: physiological release associated with natriuresis during negative pressure breathing in man.

1. Negative pressure breathing was one of the first physiological tools used to study the renal effects of redistribution of the blood volume from the peripheries to the thorax. The recent discovery of a putative natriuretic hormone (atrial natriuretic peptide, ANP) in cardiac atrial tissue has rekindled interest in the effect of the cardiovascular system on renal function. We have therefore studied the effects of this physiological manoeuvre on plasma ANP concentrations and renal responses. 2. Plasma concentrations of ANP, plasma renin activity and plasma aldosterone concentration were measured during an 80 min period of negative pressure breathing at -12 cmH2O pressure in six hydrated normal subjects. Identical control studies were performed in the same subjects at at least 1 week apart. 3. Negative pressure breathing resulted in a natriuresis and diuresis which were associated with a significant rise in plasma ANP concentration. The natriuresis occurred despite an increase in plasma renin activity and in plasma aldosterone concentration. 4. These findings, under specific carefully controlled conditions, support the previously contentious postulate that negative pressure breathing enhances sodium excretion, in addition to its well-recognized diuretic effect. They add further weight to the hypothesis that expansion of the central blood volume is an important stimulus to the release of ANP from the heart (acting by way of atrial distension), and suggest that changes of plasma ANP concentration may have induced the natriuresis which occurred in the face of a modest activation of the sodium-retaining renin-aldosterone system.