Effect of water table management and elevated CO2 on radish productivity and on CH4 and CO2 fluxes from peatlands converted to agriculture.

Anthropogenic activity is affecting the global climate through the release of greenhouse gases (GHGs) e.g. CO2 and CH4. About a third of anthropogenic GHGs are produced from agriculture, including livestock farming and horticulture. A large proportion of the UK's horticultural farming takes place on drained lowland peatlands, which are a source of significant amounts of CO2 into the atmosphere. This study set out to establish whether raising the water table from the currently used -50cm to -30cm could reduce GHGs emissions from agricultural peatlands, while simultaneously maintaining the current levels of horticultural productivity. A factorial design experiment used agricultural peat soil collected from the Norfolk Fens (among the largest of the UK's lowland peatlands under intensive cultivation) to assess the effects of water table levels, elevated CO2, and agricultural production on GHG fluxes and crop productivity of radish, one of the most economically important fenland crops. The results of this study show that a water table of -30cm can increase the productivity of the radish crop while also reducing soil CO2 emissions but without a resultant loss of CH4 to the atmosphere, under both ambient and elevated CO2 concentrations. Elevated CO2 increased dry shoot biomass, but not bulb biomass nor root biomass, suggesting no immediate advantage of future CO2 levels to horticultural farming on peat soils. Overall, increasing the water table could make an important contribution to global warming mitigation while not having a detrimental impact on crop yield.

Utilising green and bluespace to mitigate urban heat island intensity.

It has long been recognised that cities exhibit their own microclimate and are typically warmer than the surrounding rural areas. This 'mesoscale' influence is known as the urban heat island (UHI) effect and results largely from modification of surface properties leading to greater absorption of solar radiation, reduced convective cooling and lower water evaporation rates. Cities typically contain less vegetation and bodies of water than rural areas, and existing green and bluespace is often under threat from increasing population densities. This paper presents a meta-analysis of the key ways in which green and bluespace affect both urban canopy- and boundary-layer temperatures, examined from the perspectives of city-planning, urban climatology and climate science. The analysis suggests that the evapotranspiration-based cooling influence of both green and bluespace is primarily relevant for urban canopy-layer conditions, and that tree-dominated greenspace offers the greatest heat stress relief when it is most needed. However, the magnitude and transport of cooling experienced depends on size, spread, and geometry of greenspaces, with some solitary large parks found to offer minimal boundary-layer cooling. Contribution to cooling at the scale of the urban boundary-layer climate is attributed mainly to greenspace increasing surface roughness and thereby improving convection efficiency rather than evaporation. Although bluespace cooling and transport during the day can be substantial, nocturnal warming is highlighted as likely when conditions are most oppressive. However, when both features are employed together they can offer many synergistic ecosystem benefits including cooling. The ways in which green and bluespace infrastructure is applied in future urban growth strategies, particularly in countries expected to experience rapid urbanisation, warrants greater consideration in urban planning policy to mitigate the adverse effects of the UHI and enhance climate resilience.

Excellence in teaching end-of-life care: a new multimedia toolkit for nurse educators.

Nursing strongly values comfort and patient-centered care at the end of life, but little end-of-life content is included in most basic nursing education programs. An innovative way to improve nursing education about the end-of-life transition is to provide nurse educators with an electronic toolkit. This article describes a newly created multimedia toolkit (TNEEL), which includes engaging strategies for teaching and learning about end-of-life care.

The protective effects of hypoxia-induced hypometabolism in the Nautilus.

Specimens of Nautilus pompilius were trapped at depths of 225-300 m off the sunken barrier reef southeast of Port Moresby, Papua New Guinea. Animals transported to the Motupore Island laboratory were acclimated to normal habitat temperatures of 18 degrees C and then cannulated for arterial and venous blood sampling. When animals were forced to undergo a period of progressive hypoxia eventually to encounter ambient partial pressure of oxygen (PO2) levels of approximately 10 mmHg (and corresponding arterial PO2's of approximately 5 mmHg), they responded by lowering their aerobic metabolic rates to 5-10% of those seen in resting normoxic animals. Coincident with this profound metabolic suppression was an overall decrease in activity, with brief periods of jet propulsion punctuating long periods of rest. Below ambient PO2 levels of 30-40 mmHg, ventilatory movements became highly periodic and at the lowest PO2 levels encountered, ventilation occasionally ceased altogether. Cardiac output estimated by the Fick equation decreased during progressive hypoxia by as much as 75 80%, and in the deepest hypometabolic states heart rates slowed to one to two cycles of very low amplitude per minute. By the end of 500 min exposure to ambient PO2 levels of 10 mmHg or less, the anaerobic end products octopine and succinate had increased significantly in adductor muscle and heart, respectively. Increased concentrations of octopine in adductor muscle apparently contributed to a small intracellular acidosis and to the development of a combined respiratory and metabolic acidosis in the extracellular compartment. On the other hand, increases in succinate in heart muscle occurred in the absence of any change in cardiac pHi. Taken together, we estimate that these anaerobic end products would make up less than 2% of the energy deficit arising from the decrease in aerobic metabolism. Thus, metabolic suppression is combined with a massive downregulation of systemic O2 delivery to match metabolic supply to demand.

Solid-phase extraction of acidic herbicides.

A discussion of solid-phase extraction method development for acidic herbicides is presented that reviews sample matrix modification, extraction sorbent selection, derivatization procedures for gas chromatographic analysis, and clean-up procedures for high-performance liquid chromatographic analysis. Acidic herbicides are families of compounds that include derivatives of phenol (dinoseb, dinoterb and pentachlorophenol), benzoic acid (acifluorfen, chloramben, dicamba, 3,5-dichlorobenzoic acid and dacthal--a dibenzoic acid derivative), acetic acid [2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)], propanoic acid [dichlorprop, fluazifop, haloxyfop, 2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP) and silvex], butanoic acid [4-(2,4-dichlorophenoxy)butanoic acid (2,4-DB) and 4-(4-chloro-2-methylphenoxy)butanoic acid (MCPB)], and other miscellaneous acids such as pyridinecarboxylic acid (picloram) and thiadiazine dioxide (bentazon).

Comparison among soil Series and extraction methods for the analysis of trifluralin.

Accurate analytical procedures are needed to improve understanding of the fate and transport of trifluralin, a chemical widely used as a herbicide. Analytical determination of trifluralin is challenging due to its hydrophobic, yet volatile, character and its tendency to degrade into numerous metabolites. In this research, efficient analytical methods for fortified and field-incurred soils were developed for simultaneous quantitation of trifluralin, I [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine, CAS Registry No. 1582-09-8; CAS Registry No. have been provided by the author], a trifluralin metabolite, II [2,6-dinitro-N-propyl-4-(trifluoromethyl)benzenamine, CAS Registry No. 2077-99-8], and a related trifluoromethyldinitroaniline isomer of trifluralin, III [2,4-dinitro-N,N-dipropyl-6-(trifluoromethyl)benzenamine, CAS Registry No. 23106-20-9]. Extractions of trifluralin (0.5 and 2.5 microg/g) from silt loam, sandy loam, and silty clay soils were compared. A method was developed for the supercritical fluid extraction of trifluralin from soil using modified supercritical carbon dioxide, and the effects of cosolvent, pressure, and flow rate on recovery were evaluated. Supercritical fluid extraction was compared to liquid vortex extraction and automated Soxhlet (soxtec) extraction. Solid-phase extraction was examined for purifying soil extracts. Protocols were developed for analysis of extracts by gas and/or liquid chromatography. Immunoassay was investigated but proven to be impractical for this analysis. Soil properties and extraction methods were observed to affect the level of coextracted background interferences. Trifluralin exhibited concentration-dependent recovery regardless of soil series or extraction method.

The use of an independent visual background to reduce simulator side-effects.

BACKGROUND: Simulator sickness (SS) is a major problem which potentially limits interface applications that feature simulated motion. While display imperfections play a role, a large part of SS is motion sickness (MS). Sensory rearrangement theory holds that MS is related to conflicting motion cues; in the case of simulators, mainly a conflict between inertial cues (usually indicating no self-motion) and visual stimuli from the display (indicating self-motion). It is suggested that MS does not arise from conflicting motion cues per se, but rather from conflicting rest frames selected from those motion cues. There is strong evidence that the visual rest frame is heavily influenced by the visual background. Providing an independent visual background (IVB) consistent with the inertial rest frame may reduce SS, even when the simulator's content-of-interest (CI) is not consistent with the inertial rest frame. METHODS: In two experiments, a circular vection stimulus was shown for 3-4.5 min in a head-mounted display, comparing see-through (i.e., IVB) to occluded (i.e., no IVB) modes. Measures included a standard SS questionnaire and a pre-exposure ataxia measure. Experiment 2 added a visual task which forced attention into the CI and a post-exposure ataxia measure. In both experiments, subjects rated the CI as significantly more visible than the IVB. RESULTS: A large effect was found for the reduction of SS and ataxia in the first experiment, and for pre-exposure ataxia in the second. CONCLUSIONS: Future research will further test the IVB idea and examine applications to high-end simulators.

In vivo clearance of ternary complexes of vitronectin-thrombin-antithrombin is mediated by hepatic heparan sulfate proteoglycans.

Thrombin is inhibited by its cognate plasma inhibitor antithrombin, through the formation of covalent thrombin-antithrombin (TAT) complexes that are found as ternary complexes with vitronectin (VN-TAT). To determine whether the metabolism of VN-TAT ternary complexes is different from that previously reported for binary TAT complexes, plasma clearance studies were done in rabbits using human VN-TAT. 125I-VN-TAT was shown to be cleared rapidly from the circulation (t1/2alpha = 3.8 min) in a biphasic manner mainly by the liver. 125I-TAT had a similar initial clearance (t1/2alpha = 5.3 min) but had a significantly faster beta-phase clearance (t1/2beta = 42.8 min versus 85.4 min for VN-TAT; p = 0.005). Protamine sulfate and heparin abolished the rapid initial alpha-phase of 125I-VN-TAT clearance and reduced its liver-specific association and in vivo degradation. Heparin also reduced the alpha-phase clearance of 125I-TAT and was associated with the appearance of high molecular weight complexes, suggesting enhanced complex formation between VN and TAT. 125I-VN-TAT binding to HepG2 cells was reduced by competition with VN-TAT or heparin but to a much lesser extent in the presence of TAT. The binding of VN-TAT to HepG2 cells was not inhibited by competition with the low density lipoprotein receptor-related protein ligand, methylamine-alpha2-macroglobulin. 125I-VN-TAT binding was also inhibited by treating HepG2 cells with heparinase or by growing the cells in the presence of beta-D-xyloside. Finally, both heparin and chloroquine, but not methylamine-alpha2-macroglobulin, reduced the internalization and degradation of VN-TAT by HepG2 cells. Taken together, these data indicate the importance of VN in TAT metabolism and demonstrate that VN-TAT binds to liver-associated heparan sulfate proteoglycans, which mediate its internalization and subsequent intracellular degradation.

Cytokeratin 18 is expressed on the hepatocyte plasma membrane surface and interacts with thrombin-antithrombin complexes.

During experiments to identify putative hepatic receptors for thrombin-antithrombin (TAT) complexes, a 45-kDa protein was identified by ligand blotting. Following gel purification, amino acid sequencing revealed the 45-kDa TAT-binding polypeptide to be cytokeratin 18 (CK18). The presence of CK18 on the surface of intact rat hepatoma cells was demonstrated by binding of 125I-anti-CK18 antibodies. Anti-CK18 antibodies reduced the binding and internalization of 125I-TAT by rat hepatoma cells. Immunocytochemical analysis, to determine the location of CK18 in vivo, revealed a periportal gradient of CK18 staining; with hepatocytes around the portal triads demonstrating striking pericellular staining. In addition, anti-CK18 IgG associated with perfused livers to a significantly greater extent than preimmune IgG. Taken together, these data provide evidence that CK18 is found on the extracellular surface of hepatocytes and could play a role in TAT removal. Finally, these data, in conjunction with recent reports of CK8 (Hembrough, T. A., Li, L., and Gonias, S. L. (1996) J. Biol. Chem. 271, 25684-25691) and CK1 cell membrane surface expression (Schmaier, A. H. (1997) Thromb. Hemostasis 78, 101-107), indicate a novel role for these proteins as putative cellular receptors or cofactors to cellular receptors.

Pharmacokinetics and pharmacodynamics of subcutaneous interleukin-2 in HIV-infected patients.

STUDY OBJECTIVES: To assess the pharmacokinetics and pharmacodynamics of subcutaneously administered interleukin-2 (IL-2) in patients infected with the human immunodeficiency virus (HIV). DESIGN: Open, dose-escalating phase I clinical trial. SETTING: Government research hospital. PATIENTS: Eighteen patients infected with HIV. INTERVENTIONS: Recombinant IL-2 at dosages of 12, 15, or 18 MIU/day was administered subcutaneously once or twice/day for 5 consecutive days every 2 months. A total of 28 cycles of therapy were included in the analysis. MEASUREMENTS AND MAIN RESULTS: Concentrations of IL-2 in serum were determined by a commercial enzyme-linked immunosorbent assay. Interleukin-2 was well absorbed, with peak concentrations from 21.9-112.9 IU/ml. Absorption was slow, with mean (+/- SD) time to maximum of 4.4 +/- 1.8 hours and a lag time of 26.9 +/- 13.7 minutes. Elimination half-life was 3.3 +/- 0.9 hours. The concentrations had wide variability both within and among patients. Levels of tumor necrosis factor-alpha were increased. Maximum body temperature and systemic side effects were associated with peak serum levels. CONCLUSION: Interleukin-2 is well absorbed after subcutaneous injection in HIV-infected patients, and that route of administration is an alternative to intravenous infusions.

Concerns on little league elbow.

Little League elbow is a common overuse injury that will become more prevalent as more youths participate in baseball programs and other sports that involve overhead arm activities. The condition is highly treatable if diagnosed early in its development. Symptoms such as swelling and limited range of motion usually indicate an advanced overuse condition. Prevention and treatment should emphasize education of athletes, parents, and coaches about coaches about its etiology. Factors involved are proper pitching mechanics, stretching and strengthening programs, improving early recognition, and, most importantly, limiting the number of pitches thrown daily.

Prevalence of antithrombin deficiency in healthy blood donors: a cross-sectional study.

The prevalence of antithrombin (AT) deficiency in the general population has been variously estimated to be between 0.05 and 5 per 1,000 in the population; 2,491 blood donors were screened in an attempt to clarify this issue using plasma samples taken from the blood donor units. From this initial population, 122 individuals were identified as having plasma AT levels lower than 2 standard deviations below the normal mean. Twenty-two samples had evidence that thrombin had been generated during blood collection and the remaining cohort of 100 blood donors were asked to return but only 59 complied. The data obtained from these 59 were compared with that from 51 age- and sex-matched control blood donors. Both groups of subjects were assessed for previous evidence, or family history, of thrombotic events, as well as exposure to risk factors associated with the development of deep vein thrombosis (DVT). All had venous blood samples taken from which the supernatant plasma was immediately removed and quick frozen for later assaying. Only 6 of the 59 subjects with initial low AT levels had repeat AT-Xa levels below 0.80 units/ml (normal range 0.94 +/- 0.14). Upon repeating the AT-Xa determinations on new samples from these six individuals, only three were found again to be low. One was found to have a type 3 AT deficiency (an Arg47Cys substitution). The other two with a low AT level had mean functional AT-Xa levels of 0.61 and 0.71 units/ml, respectively, with correspondingly low AT:Ag levels consistent with a type 1 AT deficiency. Two of these three subjects has been in high risk situations without evidence of having developed DVT and none had evidence of venous reflux on Doppler venography. In addition, none had personal or family histories of previous thrombotic events. These present data indicate that the prevalence of AT deficiency in our blood donor population is 2 per 1,000 (95% confidence intervals: 0.7-6/1,000).

An antithrombin III assay based on factor Xa inhibition provides a more reliable test to identify congenital antithrombin III deficiency than an assay based on thrombin inhibition.

OBJECTIVES: To determine whether functional antithrombin III (AT-III) levels measured by a factor Xa inhibition (AT-III-Xa) assay identifies AT-III deficient individuals more reliably than functional AT-III levels measured by a thrombin inhibition (AT-III-IIa) assay. STUDY DESIGN: Cross-sectional study. PATIENT POPULATION: Sixty-seven members of a large family with type 2 AT-III deficiency. INTERVENTION: DNA analysis was used as the reference diagnostic standard for AT-III status and subjects were classified as AT-III deficient or non deficient according to these results. Functional AT-III levels were measured in all subjects using: 1) a chromogenic substrate for thrombin and added human thrombin (AT-III-IIa), and 2) a chromogenic substrate for factor Xa and added bovine factor Xa (AT-III-Xa). Functional heparin cofactor II (HC-II) levels were measured using a commercially available kit. The proportions of 125I-alpha-thrombin complexed to AT-III and HC-II were measured by polyacrylamide gel electrophoresis and autoradiography. RESULTS: Thirty-one (46%) individuals were classified as AT-III deficient and 36 (54%) as AT-III non deficient. AT-III-Xa assay measured a significantly lower mean AT-III value and a narrower range for individuals classified as AT-III deficient than the AT-III-IIa assay. Using the AT-III-IIa assay, six subjects had borderline AT-III levels compared to none with the AT-III-Xa assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Interdisciplinary Treatment of Musculoskeletal Pain: The EMPOWER Program.

Many individuals who experience chronic pain are able to return to work in some capacity but continue to suffer from ongoing pain problems resulting in increased absenteeism and reduced productivity on the job. These individuals continue to require ongoing medical interventions. Monthly follow-up visits to a physician rarely provide effective treatment strategies that patients can use at home. The challenge is to develop an effective and inexpensive treatment program that will assist patients in regaining or maintaining employment and decrease reliance on health care facilities. A program of this type has been developed for chronic pain sufferers, primarily those with low back and cervical spine pain. The treatment is a six-week interdisciplinary program including relaxation training, gradually increasing exercise, and significant education on behavioral and exercise strategies and nutrition for long-term pain management. This program is inexpensive, cost efficient, and may be implemented easily in a variety of settings.

Molecular cloning and expression of rabbit antithrombin III.

A cDNA containing the complete open-reading frame encoding rabbit antithrombin III (AT-III) was isolated from a rabbit liver cDNA expression library, using a specific antibody as a probe. Sequence analysis showed 84% identity between the deduced amino acid sequences of the rabbit and human proteins. A previously described cell-free expression system was used to verify the identity of the clone. The full-length cDNA was inserted into an expression vector, and messenger RNA (mRNA) transcripts generated. In vitro translation of these transcripts, in the presence of [35S]methionine, in an mRNA-dependent rabbit reticulocyte lysate system resulted in the synthesis of a 51-Kd polypeptide, as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This nonglycosylated protein was capable of forming SDS-stable complexes with human alpha-thrombin. Complex formation was significantly enhanced following the deletion of nucleotides encoding the signal peptide, and the resultant generation of a 47-Kd nonglycosylated mature protein product. When the template DNA giving rise to this product was internally truncated, two rabbit AT-III deletion mutants were generated that lacked the ability to interact with thrombin, but retained the ability to bind heparin. Cell-free expression plasmids encoding the human and rabbit AT-III mature molecules were manipulated to produce two interspecies fusion proteins. For the first, human codons were used to replace rabbit codons from residue 369-433, while in the second human codons replaced rabbit codons from residue 217-433. Both fusion proteins exhibited less efficient thrombin-complexing ability than the original cell-free-derived mature rabbit AT-III. Thus, portions of AT-III molecules from the two species, despite their high degree of homology, are not interchangeable. Knowledge of the structure of rabbit AT-III, combined with the availability of the rabbit cDNA, will permit defined experimentation aimed at understanding antithrombin III structure relative to its function in vivo.