Trophic and spatial patterns of contaminants in fishes from the Republic of the Marshall Islands in the equatorial Pacific

The Republic of the Marshall Islands (RMI) has been affected by marine pollution from militarization and urbanization. To address concerns raised by the Marshall Islands Marine Resources Authority, this study examined concentrations of dissolved contaminants in reef and pelagic fishes in the RMI and assessed potential associated risks. Metals, organochlorine pesticides, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) were examined in reef and pelagic fishes from six atolls: Kwajalein, Majuro, Jaluit, Utirik, Rongelap, and Wotje. Clear trophic patterns emerged for metals. Total arsenic was highest in higher trophic level reef fishes, particularly in the camouflage grouper (Epinephelus polyphekadion) (>100 μg g^-1 total As), but inorganic arsenic was negligible in higher trophic levels and showed an inverse trend with the highest percentages present in parrotfishes and herbivores. Copper and mercury were elevated in higher trophic level reef and pelagic fishes, respectively, and the maximum mercury concentrations (6.45 μg g^-1 in Gymnosarda unicolor) were among the highest reported in the Pacific. Conversely, cadmium and lead were highest in lower trophic levels, like surgeonfishes and parrotfishes. PCBs were more clearly linked to locations and were highest at two atolls with military history (Kwajalein and Jaluit) (>U.S. EPA Screening Value of 2.5 ppb). PAHs were ubiquitous across taxa (detected in 97% of samples), but the highest concentrations were in lower trophic levels. Organochlorine pesticides were detected at very low concentrations that do not likely pose a risk. We compare concentrations to established thresholds for human health and find that - for specific locations and species - contaminant concentrations may pose a risk to fish and other marine taxa, as well as human consumers. This study provides baseline information that aids the development of marine conservation and public health recommendations and addresses a data gap that persists for marine pollution throughout the Pacific Islands.

Myofunctional therapy. Part 1: Culture, industrialisation and the shrinking human face

Culture, industrialisation and the shrinking human face: Why is it important? Over the past 300,000 years, not only has the way we consume food from birth through our lifetime changed, there have also been changes related to the methods of food preparation, availability, processing, and storage. These diet-related factors, along with other epigenetic factors, have led to a widespread increase in orofacial myofunctional disorders (OMDs) and resultant human malocclusion phenotypes (HMPs) worldwide. Currently there is an increasing need for resolution of HMPs in early childhood and associated OMDs. This review will include reports of cases and describe the nature of the problem and strategies for effective solutions.

Establishing scald prevention measures in UK maternity units from takeaway drinks

AIM

To identify policies on the consumption of hot drinks by patients and visitors on all perinatal and postnatal wards in the United Kingdom, and to seek the opinions of members of the wider burns MDT as to whether standardised patient education or regulation of hot drinks around newborn babies is required.

METHODS

All maternity units with postnatal wards across the United Kingdom were surveyed to establish availability of hot drinks on site and whether these were permitted on postnatal wards around infants. An online questionnaire was distributed to members of the British Burn Association to ascertain opinions on hot drinks policies.

RESULTS

Hot takeaway drinks were permitted around newborn infants in 194 of surveyed postnatal wards and were only banned by two units. The online survey received 49 responses from different members of the British Burn Association. Thirty responders (61%) supported a takeaway hot drink ban, while those against the policy would alternatively encourage patient education, dedicated drinking areas and introduction of safety measures.

CONCLUSIONS

Almost every postnatal unit in the UK has access to hot drink retailers on site allowing parents and visitors to bring them into close contact with babies. With varying local regulations, this poses potentially serious consequences during feeding or carrying. We propose a standardised antenatal education be made available, together with standardised designated areas on wards for parents and visitors to consume hot drinks away from infants.

Corrosive attacks in the UK - Psychosocial perspectives and decontamination strategies

Acid attacks, or vitriolage, are defined as violent assaults involving the deliberate throwing of an acid or similarly corrosive substance with the intention to "maim, disfigure, torture or kill" [1]. The Acid Survivors Trust International suggest a prevalence of 1500 attacks reported worldwide per annum, although this is likely to be an underestimate by 40% [2]. The UK is thought to have one of the highest of rates of recorded corrosive attacks, with an increase from 228 attacks in 2012 to 601 in 2016. Most were reported by the London Metropolitan police force followed by Northumbria, Cambridgeshire, Hertfordshire, Greater Manchester and Humberside [[2]]. The chemical agents involved include acids, alkalis, oxidising and reducing agents, alkylating and chelating agents and solvents. They cause injury by producing a chemical interaction which can lead to extensive tissue destruction and extreme pain. Herein, we present a review on the changing epidemiology of corrosive attacks in the UK and currently employed management strategies.

Temperature dissociation of liquids in reusable thermoplastic containers-An eco-friendly scald risk?

Recent global concern regarding the impact of plastic waste on the environment has resulted in efforts to utilise reusable drink containers. Research is lacking regarding temperature dissociation of drinks in reusable thermoplastic cups. This study aimed to compare the cooling time of two common hot drinks sold at a UK retailer, in the three vessels they are sold; ceramic, disposable paper (with and without lid) and reusable thermoplastic cups (with and without lid). All temperatures were collated from 250 ml volumes of black Americano coffee or café latte in the three different containers. The cooling time was measured every sixty seconds using a standardised digital thermocouple thermometer until a threshold liquid temperature of 43 °C was reached. All experiments were performed in triplicate and temperatures converted to a dimensionless logarithmic scale prior to statistical analysis. Cooling time was significantly slower for lidded cups irrespective of material. Unlidded thermoplastic cups significantly slowed cooling times for both black Americano coffee and café latte compared to ceramic and unlidded disposable paper cups. The growing trend in reusable cups does not in itself pose an increased risk of scald injury. However, we consider that the potentially increased ambulatory behaviour associated with using a lidded rather than unlidded cup may increase scald risk. We propose that further consumer guidance should be disseminated regarding the use of any lidded takeaway container to prevent scalds in both adults and children.

Tranexamic acid in life-threatening military injury and the associated risk of infective complications

BACKGROUND

Tranexamic acid (TXA) has been shown to reduce mortality from severe haemorrhage. Although recent data suggest that TXA has anti-inflammatory properties, few analyses have investigated the impact of TXA on infectious complications in injured patients. The aim was to examine the association between TXA administration and infection risk among injured military personnel.

METHODS

Patients who received TXA were matched by Injury Severity Score with patients who did not receive TXA. Conditional logistic regression was used to examine risk factors associated with infections within 30 days. A Cox proportional analysis evaluated risk factors in a time-to-first-infection model.

RESULTS

A total of 335 TXA recipients were matched with 626 patients who did not receive TXA. A greater proportion of TXA recipients had an infection compared with the comparator group (P < 0·001). Univariable analysis estimated an unadjusted odds ratio (OR) of 2·47 (95 per cent c.i. 1·81 to 3·36) for the association between TXA and infection risk; however, TXA administration was not significant in multivariable analysis (OR 1·27, 0·85 to 1·91). Blast injuries, intensive care unit (ICU) admission, and receipt of 10 units or more of blood within 24 h after injury were independently associated with infection risk. The Cox proportional model confirmed the association with ICU admission and blood transfusion. Traumatic amputations were also significantly associated with a reduced time to first infection.

CONCLUSION

In life-threatening military injuries matched for injury severity, TXA recipients did not have a higher risk of having infections nor was the time to develop infections shorter than in non-recipients. Extent of blood loss, blast injuries, extremity amputations and ICU stay were associated with infection.

Deep brain stimulation and cognitive decline in Parkinson's disease: The predictive value of electroencephalography

Some Parkinson's disease (PD) patients treated with subthalamic nucleus deep brain stimulation (STN-DBS) develop new-onset cognitive decline. We examined whether clinical EEG recordings can be used to predict cognitive deterioration in PD patients undergoing STN-DBS. In this retrospective study, we used the Grand Total EEG (GTE)-score (short and total) to evaluate pre- and postoperative EEGs. In PD patients undergoing STN-DBS (N = 30), cognitive functioning was measured using Mini-Mental State Test and DemTect before and after surgery. Severity of motor impairment was assessed using the Unified Parkinson's Disease Rating Scale-III. Patients were classified into patients with or without cognitive decline after STN-DBS surgery. Epidemiological data, pre- and postoperative EEG recordings as well as neuropsychological and neurological data, electrode positions and the third ventricle width were compared. A logistic regression model was used to identify predictors of cognitive decline. Motor deficits significantly improved from pre- to post-surgery, while the mean GTE-scores increased significantly. Six patients developed cognitive deterioration 4-12 months postoperatively. These patients had significantly higher preoperative GTE-scores than patients without cognitive deterioration, although preoperative cognitive functioning was comparable. Electrode positions, brain atrophy and neurological data did not differ between groups. Logistic regression analysis identified the GTE-score as a significant predictor of postoperative cognitive deterioration. Data suggest that the preoperative GTE-score can be used to identify PD patients that are at high risk for developing cognitive deterioration after STN-DBS surgery even though their preoperative cognitive state was normal.

Subjectively perceived personality and mood changes associated with subthalamic stimulation in patients with Parkinson's disease

BACKGROUND

Clinical and ethical implications of personality and mood changes in Parkinson's disease (PD) patients treated with subthalamic deep brain stimulation (STN-DBS) are under debate. Although subjectively perceived personality changes are often mentioned by patients and caregivers, few empirical studies concerning these changes exist. Therefore, we analysed subjectively perceived personality and mood changes in STN-DBS PD patients.

METHOD

In this prospective study of the ELSA-DBS group, 27 PD patients were assessed preoperatively and 1 year after STN-DBS surgery. Two categories, personality and mood changes, were analysed with semi-structured interviews. Patients were grouped into personality change yes/no, as well as positive/negative mood change groups. Caregivers were additionally interviewed about patients' personality changes. Characteristics of each group were assessed with standard neurological and psychiatric measurements. Predictors for changes were analysed.

RESULTS

Personality changes were perceived by six of 27 (22%) patients and by 10 of 23 caregivers (44%). The preoperative hypomania trait was a significant predictor for personality change perceived by patients. Of 21 patients, 12 (57%) perceived mood as positively changed. Higher apathy and anxiety ratings were found in the negative change group.

CONCLUSIONS

Our results show that a high proportion of PD patients and caregivers perceived personality changes under STN-DBS, emphasizing the relevance of this topic. Mood changed in positive and negative directions. Standard measurement scales failed to adequately reflect personality or mood changes subjectively perceived by patients. A more individualized preoperative screening and preparation for patients and caregivers, as well as postoperative support, could therefore be useful.

Stem cell application in acute burn care and reconstruction

Burn injuries have a consistently high rate of mortality and morbidity, principally due to sepsis and systemic inflammation. Furthermore, wound closure is often troubled by a limited supply of autologous skin graft availability. Researchers are now looking at augmenting alternative sources for tissues engineering, including stem cells in the bone marrow, fat and hair follicles. Many studies suggest that the ability of stem cells to augment the clinical care of thermally-injured patients shows great potential; however, while our understanding of stem-cell biology has expanded dramatically over the last two decades, significant insight is still required so the full potential of these cells can be safely harnessed and transferred to patient care. This article provides a commentary on the evidence supporting a role for stem-cell therapy in acute burn care and tissue reconstruction, with particular reference to those in the bone marrow, adipose tissue and hair follicle.

Curtain gastroplasty as an option in high risk emergency hiatus hernia repair

INTRODUCTION

We describe a novel surgical technique used in the case of an 86-year-old Caucasian man with multiple comorbidities who presented with upper intestinal obstruction caused by a large paraoesophageal hiatus hernia and concurrent urinary sepsis.

METHODS

The technique, which minimises both operative time and surgical trauma in this situation, uses the fundus of the stomach in a modified Dor anterior fundoplication as a gastric fundoplasty to close the defect. The total operative time was 70 minutes.

RESULTS

The patient's recovery was complicated by a lower respiratory tract infection but he was discharged 14 days after surgery with a premorbid oral intake and activity level.

CONCLUSIONS

We believe this curtain gastroplasty technique represents another surgical option to reduce operative time and trauma in a subgroup of high risk patients presenting with life threatening complications of a large hiatus hernia who have limited physiological reserve and evidence of current ongoing sepsis.

Lipoma or liposarcoma? A cautionary case report

MERRF syndrome (myoclonic epilepsy with ragged-red fibres) is a mitochondrial encephalomyopathy characterised by a mixed seizure disorder and myoclonus. The condition is associated with multiple large cervical lipomas that often require surgical excision. Comprehensive clinical examination combined with pre-operative radiographic imaging is vital in such cases to help differentiate benign fatty masses from potential liposarcomas. We describe a case in which a lipoma-like liposarcoma was identified following excision of what was expected, on clinical and radiological grounds, to be a lipoma. This case highlights the potential for sarcomatous changes in suspicious lipomas, and the key role that imaging plays in differentiating benign from malignant.

Some studies of friction and lubrication using an instrumented tablet machine

Samples of crystalline aspirin, hexamine, and sodium chloride, and a granulation of hexamine were compressed on an instrumented tablet machine. Further samples of these materials, together with samples of sucrose and sucrose granulation, were lubricated with 2% magnesium stearate −100 mesh powder and compacted under similar conditions. The effect of magnesium stearate on die wall friction depends on the ease of deformation of the base particles. For the materials used there is a linear relationship of the form Fa = kd(Pm.A) and a linear relationship exists between Fe and Fd up to the point where Fe becomes constant. Granulations required larger ejection forces at a given pressure than the corresponding crystalline material, particularly when the materials were lubricated; constant values of Fe were associated with compaction pressures at which the density of the ejected tablets became maximal. Values of Fe for tablets of unlubricated sodium chloride and hexamine granulation depend on particle size; the size of other materials used caused no such effect. Lubrication eliminated this size effect.

A comparison of tablet lubricant efficiencies for a sucrose granulation using an instrumented tablet machine

Thirteen materials have been assessed as lubricants when added to a sucrose granulation and compressed on an instrumented tablet machine. Values of ejection force, force lost to die wall, and punch force ratio for each lubricated sample were compared, and the order of efficiency as lubricants was compared with the shear of lubricant powder compacts. The most efficient lubricants are those materials of lowest melting point, and not those with the smallest shear strength value as measured in a punch penetration test.

Is the etiology of eosinophilic esophagitis in adults a response to allergy or reflux injury? Study of cellular proliferation markers

Recent research suggests that allergy may be the key factor in the etiology of eosinophilic esophagitis (EE); however, historically, the condition was hypothesized as related to reflux injury to the esophageal mucosa. We studied this hypothesis by comparing markers of inflammation and cellular proliferation in EE and reflux esophagitis. Lower esophageal biopsies of adult patients with EE (n = 10), reflux esophagitis (n = 8), and normal controls (n = 13) were assessed quantitatively for the expression of the cyclooxygenase-2 (COX-2) enzyme, cellular proliferation, and oncogenic resistance to apoptosis using monoclonal antibodies for COX-2, Ki-67, and Bcl-2, respectively. Normal esophageal epithelium demonstrated weak diffuse uptake of COX-2 stain in the basal layer. No COX-2 expression was demonstrated in the EE group, significantly less than the control and reflux groups (P < 0.01 and P < 0.001, respectively). Cellular proliferation measured by Ki-67 expression was higher in EE and reflux compared with control (P < 0.001 and P < 0.01). Ki-67 expression, and thus degree of hyperplasia, appeared greater in EE than reflux, but was not statistically significant (P = 0.228). The degree of apoptosis was similar in all study groups. EE and reflux esophagitis are proliferative conditions expressing Ki-67 in higher concentrations than control. Mucosal proliferation in reflux esophagitis is COX-2 dependent. This novel research in EE has demonstrated downregulation of COX-2 expression compared with reflux esophagitis and control. We hypothesize that the allergy-related cytokine IL-13 known to inhibit COX-2 expression and found in high concentrations in EE as responsible for this. The pathogenesis of EE is likely dependent on allergy rather than reflux injury to the esophagus.

Plasma gastrin measurement cannot be used to diagnose a gastrinoma in patients on either proton pump inhibitors or histamine type-2 receptor antagonists

BACKGROUND

Patients with a gastrinoma are treated with proton pump inhibitors (PPI) and histamine type-2 receptor antagonists (H2). In order to diagnose a gastrinoma these drugs must be discontinued, but this increases the risk of gastrointestinal perforation. We aimed to determine if a gastrinoma could be diagnosed without cessation of PPI/H2 therapy.

METHODS

In all, 90 patients (controls and patients diagnosed with a gastrinoma both on and off PPI/H2 therapy) were recruited, and plasma gastrin measured.

RESULTS

Patients with a gastrinoma on PPI/H2 medication had a significantly higher fasting plasma gastrin concentration than control patients on PPI/H2 medication (298+/-33 versus 204+/-30 pmol/L, P = 0.01). However, there was substantial overlap between gastrin levels in these two groups.

CONCLUSION

This study confirms that a gastrinoma cannot be diagnosed on the basis of a fasting plasma gastrin assay while patients remain on PPI/H2 therapy.

Current approaches to the management of ovine footrot

Ovine footrot remains the most important cause of lameness in sheep flocks in the UK, despite the existence of proven methods for the control of the disease. Recent research suggests that sheep farmers may be unaware of these methods and may allocate greater resources to treatment of footrot rather than to its prevention. Foot paring, topical treatments, vaccination and parenteral antibiotic therapy all have a role in treating sheep with advanced footrot infections, but prevention of severe infections is best achieved by the timely implementation of control programmes. These are usually based on footbathing and vaccination. For control programmes to be effective it is essential that the pathogenesis and epidemiology of footrot is understood and that control methods are implemented at appropriate times in the season, depending on climatic and pasture conditions. This article reviews these strategies and makes recommendations for steps to reduce the spread of footrot between flocks and to reduce the incidence of footrot within UK flocks.

Eosinophilic oesophagitis: a novel treatment using Montelukast

BACKGROUND

Eosinophilic oesophagitis is a rarely diagnosed condition involving eosinophil infiltration of the oesophageal mucosa and creating significant symptoms of dysphagia. Failure to diagnose this disorder relates to reluctance to biopsy an apparently normal oesophagus. This is essential for histological diagnosis. To date, treatment success has been achieved only with corticosteroids. We describe here the use of an eosinophil stabilising agent Montelukast for the symptomatic relief of these patients.

PATIENTS AND METHODS

Twelve patients have been identified with this condition in our unit since 1995, after thorough investigation of their dysphagia. We commenced eight of these patients on the leukotriene receptor antagonist Montelukast to symptomatically improve their swallowing while avoiding the use of long term corticosteroids.

RESULTS

Many of these patients had been previously misdiagnosed, and therefore inappropriately and unsuccessfully treated for an extensive period prior to referral to our unit. All patients were unresponsive to acid suppression therapy alone but showed improvement in their swallowing on Montelukast. Six of eight reported complete subjective improvement, five patients remaining completely asymptomatic on a maintenance regimen.

CONCLUSIONS

Eosinophilic oesophagitis is a disease that is often misdiagnosed due to lack of awareness and reluctance of clinicians to biopsy an apparently normal oesophagus in dysphagic patients, and therefore obtain a histological diagnosis. Investigation of these patients adds further evidence to this condition being a separate pathological state from gastro-oesophageal reflux and eosinophilic enteritis. Montelukast has been found to be of significant help in the symptomatic control of these patients while avoiding long term corticosteroids use.

A method for identification of inhibitors of the phosphorylation reactions of bacterial response regulator proteins using (31)P nuclear magnetic resonance spectroscopy

Bacterial response regulators are attractive targets for antibacterial drug development, yet random screening against these targets has failed as yet to identify chemicals that constitute viable leads. Alternative methods to provide leads for drug development based on identification and optimization of low affinity ligands from NMR screens have been described. However, leads from these processes still require verification in a bioassay, which is often problematic if compounds have unfavorable optical and solubility properties. A simple method, based on using NMR to observe the activity of the target, is described. It has the advantages of being able to characterize both low affinity leads and a wider selection of compounds in a structure activity relationships series, without the problems affecting a fluorescence assay. In this example we use (31)P to monitor the turnover of a bacterial response regulator, but the generic approach could be applied to other nuclei and thus a range of biological systems.

P2X receptor immunoreactivity in different arteries from the femoral, pulmonary, cerebral, coronary and renal circulations

The expression of the seven P2X receptor subunits (P2X1-7) in the rat vascular system was determined using subtype-selective antibodies. Arteries of different sizes (from arterioles to conduit vessels) from a range of vascular beds were used to give an overview of receptor expression. P2X1 receptor immunoreactivity was detected in the smooth muscle layer of arteries. The relative level of P2X1 receptor immunoreactivity was dependent on the size of the artery and the vascular bed; expression was highest in small and medium arteries. P2X4 receptors were detected in all arteries; once again, the relative level of expression was dependent on the size of the artery and the vascular bed. P2X5 receptor immunoreactivity was barely detectable in most arteries studied. P2X7 receptor immunoreactivity was generally punctate and associated with the outer adventitial layer. Immunoreactivity for P2X2, P2X3 and P2X6 receptors was not detected in arteries. These results demonstrate that arteries express multiple P2X receptor subunits and that there is a heterogeneity in the level of expression. The properties of artery P2X receptors correspond to homomeric P2X1 receptors, and the function of P2X4 and P2X5 receptor subunits in arteries is unclear.

Lack of run-down of smooth muscle P2X receptor currents recorded with the amphotericin permeabilized patch technique, physiological and pharmacological characterization of the properties of mesenteric artery P2X receptor ion channels

Immunoreactivity for P2X(1), P2X(4) and P2X(5) receptor subtypes was detected in the smooth muscle cell layer of second and third order rat mesenteric arteries immunoreactivity, for P2X(2), P2X(3), P2X(6) and P2X(7) receptors was below the level of detection in the smooth muscle layer. P2X receptor-mediated currents were recorded in patch clamp studies on acutely dissociated mesenteric artery smooth muscle cells. Purinergic agonists evoked transient inward currents that decayed rapidly in the continued presence of agonist (tau approximately 200 ms). Standard whole cell responses to repeated applications of agonist at 5 min intervals ran down. Run-down was unaffected by changes in extracellular calcium concentration, intracellular calcium buffering or the inclusion of ATP and GTP in the pipette solution. Run-down was overcome and reproducible responses to purinergic agonists were recorded using the amphotericin permeabilized patch recording configuration. The rank order of potency at the P2X receptor was ATP=2 methylthio ATP>alpha, beta-methylene ATP>CTP=l-beta,gamma-methylene ATP. Only ATP and 2meSATP were full agonists. The P2 receptor antagonists suramin and PPADS inhibited P2X receptor-mediated currents with IC(50)s of 4 microM and 70 nM respectively. These results provide further characterization of artery P2X receptors and demonstrate that the properties are dominated by a P2X(1)-like receptor phenotype. No evidence could be found for a phenotype corresponding to homomeric P2X(4) or P2X(5) receptors or to heteromeric P2X(1/5) receptors and the functional role of these receptors in arteries remains unclear.

P2 purinoceptor-mediated control of rat cerebral (pial) microvasculature; contribution of P2X and P2Y receptors

Purine and pyrimidine nucleotides evoke changes in the vascular tone of medium to large cerebral vessels through the activation of P2 purinoceptors. We have applied P2 receptor drugs to rat pial arterioles and measured changes in arteriole diameter (o.d. 40-84 micrometer at rest), and recorded currents from arteriolar smooth muscle cells using patch-clamp techniques. Transient vasoconstrictions and rapidly inactivating currents were evoked by alpha,beta-methylene ATP (0.1-30 micrometer) and were sensitive to the P2 receptor antagonists suramin and iso-PPADS. UTP and UDP (0.1-1000 micrometer) evoked sustained suramin-sensitive vasoconstrictions. ATP (0.1-1000 micrometer) and 2-methylthioATP (2MeSATP, 300 micrometer) evoked transient vasoconstrictions followed by sustained vasodilatations. ADP application resulted in only vasodilatation (EC50 approximately 4 micrometer). Vasodilator responses to ATP, 2MeSATP or ADP were unaffected by suramin (100 micrometer). RT-PCR analysis indicated that P2X1-7 and P2Y1,2,6 RNA can be amplified from the pial sheet. Our results provide direct evidence for the presence of functional P2X receptors with a phenotype resembling the P2X1 receptor subtype on cerebral resistance arterioles. The pharmacological properties of the pyrimidine-evoked responses suggest that a combination of P2Y2- and P2Y6-like receptors are responsible for the sustained vasoconstrictions. It is therefore likely that the nucleotides and their associated receptors are involved in a complicated regulatory system to control cerebral blood pressure.

Comparison of P2X receptors in rat mesenteric, basilar and septal (coronary) arteries

alpha beta meATP-evoked concentration-dependent, PPADS-sensitive, desensitising, P2X receptor-mediated, constrictions of mesenteric, basilar and septal artery rings with EC(50) values of 1, 1 and 30 microM, respectively. In patch clamp studies on acutely dissociated artery smooth cells alpha beta meATP-evoked transient inward currents (tau approximately 100 ms) with mean current densities of approximately 340, 175 and 120 pA/pF, respectively. P2X(1) receptor immunoreactivity was expressed in mesenteric and basilar arteries and this receptor subunit appears to dominate the P2X receptor phenotype in these vessels. In contrast P2X(1) receptor immunoreactivity was not detected in septal arteries and the alpha beta meATP sensitivity of constriction was not consistent with the involvement of P2X(1) receptors. These results suggest that not all arteries share a common P2X receptor phenotype.

External exposure to radionuclides accumulated in shoreline sediments with an application to the lower Clinch River

A simple analytical method was developed to estimate external doses from exposure to contaminated riverine shorelines. The method consists of deriving an adjustment factor that accounts for the geometry of the riverine shoreline; the adjustment factor is applied to the dose-rate coefficients already available for infinite contaminated surfaces. Such a geometry factor circumvents very complex radiation transport calculations which would otherwise be necessary to model exposures to a finite contaminated surface. For instance, for radionuclides emitting gamma rays of energies above 600 keV (e.g., 137Cs), the published dose-rate coefficients must be reduced by 75%, 60%, 50%, and 33% for shoreline widths of 4, 10, 20, and 50 m, respectively. The geometry factor changes only mildly with the energy of the gamma radiation. This property allows for the geometry factor to be used for radionuclides emitting multiple gamma rays of various energies. If a quick analysis is desired, the geometry factors derived for 137Cs can be used for all radionuclides. More refined analysis can be performed by deriving geometry factors for each radionuclide according to its gamma spectrum. Also, the mild variation with energy allows the geometry factors to be applied to the case when radionuclides are accumulated in layers under the soil surface, and not only to the case when radionuclides are deposited onto the soil surface. Empirical relationships between the geometry factor and the dimension of the shoreline were provided so that one can obtain values of the geometry factor for any shoreline width. These relationships can be easily used to account for the uncertainty in the dimension of the shoreline. The method was applied to derive similar adjustment factors for contaminated surfaces of other simple geometries (e.g., circular surfaces). An example of how this method can be applied to its full extent is presented for the case of external exposure to the shores of the lower Clinch River. This river received large amounts of 137Cs, 60Co, 106Ru, 95Zr, 95Nb, 144Ce, and 90Sr released during 1944-1991 from the Oak Ridge Reservation in Oak Ridge, Tennessee.

Reduced vas deferens contraction and male infertility in mice lacking P2X1 receptors

P2X1 receptors for ATP are ligand-gated cation channels, present on many excitable cells including vas deferens smooth muscle cells. A substantial component of the contractile response of the vas deferens to sympathetic nerve stimulation, which propels sperm into the ejaculate, is mediated through P2X receptors. Here we show that male fertility is reduced by approximately 90% in mice with a targeted deletion of the P2X1 receptor gene. Male mice copulate normally--reduced fertility results from a reduction of sperm in the ejaculate and not from sperm dysfunction. Female mice and heterozygote mice are unaffected. In P2X1-receptor-deficient mice, contraction of the vas deferens to sympathetic nerve stimulation is reduced by up to 60% and responses to P2X receptor agonists are abolished. These results show that P2X1 receptors are essential for normal male reproductive function and suggest that the development of selective P2X1 receptor antagonists may provide an effective non-hormonal male contraceptive pill. Also, agents that potentiate the actions of ATP at P2X1 receptors may be useful in the treatment of male infertility.

Effects of diadenosine polyphosphates (Ap(n)As) and adenosine polyphospho guanosines (Ap(n)Gs) on rat mesenteric artery P2X receptor ion channels

Diadenosine polyphosphates (Ap(n)As, n=3 - 7) and adenosine polyphospho guanosines (Ap(n)Gs, n=3 - 6) are naturally occurring vasoconstrictor substances found in platelets. These vasoconstrictor actions are thought to be mediated through the activation of P2X receptors for ATP. The effects of Ap(n)As and Ap(n)Gs at P2X receptors on rat mesenteric arteries were determined in contraction studies and using the patch clamp technique on acutely dissociated artery smooth muscle cells. P2X(1) receptor immunoreactivity was detected in the smooth muscle layer of artery rings. The sensitivity to alpha,beta-methylene ATP and desensitizing nature of rat mesenteric artery P2X receptors correspond closely to those of recombinant P2X(1) receptors. Ap(4)A, Ap(5)A and Ap(6)A evoked concentration dependent P2X receptor inward currents which desensitized during the application of higher concentrations of agonist. The agonist order of potency was Ap(5)A> or = Ap(6)A> or = Ap(4)A >> Ap(3)A. Ap(2)A and Ap(7)A were ineffective. Similar results were obtained in contraction studies except for Ap(7)A which evoked a substantial contraction. Ap(n)Gs (n=2 - 6)(30 microM) evoked P2X receptor inward currents in mesenteric artery smooth muscle cells. Ap(n)Gs (n=4 - 6) were less effective than the corresponding Ap(n)A. This study shows that at physiologically relevant concentrations Ap(n)As and Ap(n)Gs can mediate contraction of rat mesenteric arteries through the activation of P2X(1)-like receptors. However the activity of the longer chain polyphosphates (n=6 - 7) may be overestimated in whole tissue studies due to metabolic breakdown to yield the P2X receptor agonists ATP and adenosine tetraphosphate. British Journal of Pharmacology (2000) 129, 124 - 130

Inhibition of vasoconstriction and Ca2+ currents mediated by neuropeptide Y Y2 receptors

The effects of neuropeptide Y (NPY) and agonists selective for NPY Y1 and Y2 receptors were studied on contraction and Ca2+ currents in arterial smooth muscle. In isolated arterioles from the guinea pig small intestine, small brief constrictions were evoked by depolarising the arteriolar smooth muscle using high K+ solution applied from a micropipette. The constrictions were reduced in amplitude by the Y2-selective agonists PYY(13-36) and N-acetyl[Leu28, Leu31]NPY-(24-36) in concentrations from 20-100 nM. NPY or the Y1 selective agonist [Leu31 Pro34]NPY in concentrations from 50 pM to 100 nM increased the amplitude of the constrictions, with a maximum effect at 10 nM. Smooth muscle cells were isolated from rat small mesenteric arteries, and voltage-activated Ca2+ currents measured by whole cell patch clamping. The peak amplitude of the Ca2+ currents was decreased by N-acetyl[Leu28, Leu31]NPY-(24-36), and by NPY (100 nM). [Leu31, Pro34]NPY either had no effect or slightly increased the Ca2+ currents. We conclude that Y2 receptors on vascular smooth muscle can reduce Ca2+ currents induced by depolarisation, and thus oppose constriction caused by smooth muscle depolarisation.

Estimated folate intakes: data updated to reflect food fortification, increased bioavailability, and dietary supplement use

BACKGROUND

There is a critical need to estimate dietary folate intakes for nutrition monitoring and food safety evaluations, but available intake data are seriously limited by several factors.

OBJECTIVE

Our objective was to update 2 national food consumption surveys to reflect folate intakes as a result of the recently initiated food fortification program and to correct folate intakes for the apparently higher bioavailability of synthetic folic acid (SFA; ie, folate added to foods or from dietary supplements) than of naturally occurring folate so as to express intakes as dietary folate equivalents.

DESIGN

It was not possible to chemically analyze foods, so adjustments were made to food-composition data by using information about food ingredients and characteristics. Total folate intakes were estimated for several sex and age groups by using the modified data coupled with dietary supplement use.

RESULTS

Within the limitations of the data, our findings suggested that 67-95% of the population met or surpassed the new estimated average requirement, depending on the sex and age group and survey. Nonetheless, some subgroups had estimated intakes below these standards. Estimated SFA intakes suggested that approximately 15-25% of children aged 1-8 y, depending on the survey, had intakes above the newly established tolerable upper intake level. We estimated that 68-87% of females of childbearing age had SFA intakes below the recommended intake of 400 microgram/d, depending on the age group and survey.

CONCLUSION

There is a need to explore ways to improve folate intakes in targeted subgroups, including females of childbearing age, while not putting other population groups at risk of excessive intakes.

Health claims and observational human data: relation between dietary fat and cancer

The US Food and Drug Administration review that provided the basis for authorizing a food-label health claim linking the risk of cancer to dietary fat intake illustrated several considerations in the use of epidemiologic data, and observational data in particular, to support dietary recommendations. The review suggested the need for clear and established criteria for judging the quality of observational human data as well as the importance of making the evaluation process for individual studies transparent and organized. The review, which provided for a claim in the absence of controlled human studies, also suggested that observational data may play a greater role when the nature of the relation to be described by a health-claim statement is broad and general rather than targeted and specific. Of particular importance was the relevance of available data to the questions inherent in showing a diet-disease relation, the need to consider the totality of the evidence, and the key role that existing authoritative reports must play in establishing the basis for relation.

Restriction endonuclease profiles of orf virus isolates from the British Isles

A comparison of DNA profiles of representative isolates of orf virus, obtained using four different restriction endonucleases (RE), showed that the enzyme EcoRI could be used to discriminate between wild-type virus isolates and vaccine strains. The enzyme was used to compare the RE profiles of orf virus isolates from 43 outbreaks of orf that occurred in vaccinated flocks between 1988 and 1993; 21 outbreaks yielded wild-type virus, 10 yielded vaccine viruses, three produced both vaccine and wild-type viruses and no clear result was obtained from nine of the outbreaks. From the 21 outbreaks yielding wild-type viruses, 28 orf virus isolates had clear RE profiles and 15 distinct RE profiles were recorded. Usually only one virus type was associated with each outbreak but from two farms, two different wild-type viruses were recovered. No predominant genotype was identified, with four RE profile types being recovered for more than one outbreak. From the more severe form of orf involving the buccal cavities of lambs only wild-type viruses were recovered, with at least four different genotypes being represented.

2',3'-O-(2,4,6- trinitrophenyl) adenosine 5'-triphosphate (TNP-ATP)--a nanomolar affinity antagonist at rat mesenteric artery P2X receptor ion channels

1. P2X receptor activation by alpha,beta-meATP evoked inward currents in acutely dissociated rat mesenteric artery smooth muscle cells and contractions of whole artery rings. 2. The selective P2X1 and P2X3 receptor antagonist TNP-ATP inhibited P2X receptor mediated inward currents in response to 3 microM alpha,beta-meATP (an approximately EC90 concentration) with an IC50 of approximately 2 nM. This provides further evidence that the P2X receptor underlying membrane depolarisation associated with P2X receptor activation can be accounted for by the expression of P2X1 receptors. 3. TNP-ATP inhibited alpha,beta-meATP induced contractions with an IC50 of approximately 30 microM and had non-specific effects on smooth muscle contraction. 4. The reduced potency of TNP-ATP in whole tissue experiments probably reflects the breakdown of TNP-ATP by nucleotidases. Thus, TNP-ATP is of limited use in whole tissue experiments as a P2X receptor antagonist.

Sudden death in sheep associated with Clostridium sordellii

Clostridium sordellii was isolated from 37 sheep, in 29 flocks, which died suddenly between 1993 and 1995. The sheep were of all ages, but the most severe gross lesions affected lambs four to 10 weeks of age. In older weaned lambs and ewes the gross changes were less marked and more variable. Thirty sheep suffering from a variety of other conditions were examined and C sordellii was not isolated. The isolation of C sordellii has been reported only twice before from sheep in Britain, and on both occasions no detailed investigations were described. The evidence from this study indicates that C sordellii should be considered when investigating the cause of sudden death in sheep of all ages in Britain.

Reduction of vasoconstriction mediated by neuropeptide Y Y2 receptors in arterioles of the guinea-pig small intestine

Brief applications of a high-K+ solution were used to evoke transient constrictions of arterioles from the guinea-pig small intestine. Analogues of neuropeptide Y (NPY) selective for Y2-receptors reduced the constrictions, whereas NPY or a Y1-selective analogue potentiated the constrictions. We conclude that arteriolar smooth muscle has both Y1 and Y2 receptors, and suggest that Y2 receptors inhibit vasoconstriction by modulating the opening of voltage-sensitive Ca2+ channels. This may be related to the role of NPY that is present in some vasodilator nerves.