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Background ESC guidelines recommend measurement of troponin T in patients with hypertrophic cardiomyopathy (HCM) because high concentrations are associated with cardiovascular events, heart failure and death. The cardiac Troponin I subunit is not expressed in skeletal muscle making it a cardio-specific isoform. The use of troponin biomarkers in management of patients HCM is limited because concentrations only weakly correlate with clinical parameters. Most studies are small, and few have examined their relation with genotype and mortality. Purpose To assess the relationship between high-sensitive troponin I (hsTnI) and characteristics of adults with HCM. Methods Patients included were adults with an established diagnosis of HCM referred to a single centre for genetic testing. Demographic, clinical and imaging data were recorded at baseline. Echocardiography and cardiac magnetic resonance (CMR) were performed according to EACVI standards. Quantification of late gadolinium enhancement (LGE) was performed using the 5 SD quantitative threshold. Genotype was evaluated using a 16 gene panel in an accredited UK laboratory. Pathogenic and likely pathogenic variants were considered as a positive genotype. Serum hsTnI was measured by a two-site electrochemiluminescence immunoassay on a Roche E170 analyser. Normal values for the assay 0–34 ng/L for males and 0–16 ng/L for females. Results 313 patients (n=200, 64% male) median age 57 (IQR 47–68) years were included. hsTnI concentration was abnormal in 69 (22%) patients. An abnormal hsTnI was more common in females (n=36, 32%) compared to males (n=33, 17%, c2 9.9, p Conclusions In HCM, patients with abnormal hsTnI concentration have higher LV mass and LVOT gradient and more fibrosis. Whilst mortality is higher in those with abnormal hsTnI, sudden cardiac death may occur with a normal hsTnI. It may not be appropriate to extrapolate hsTnI sex-specific thresholds used in the diagnosis of myocardial infarction to HCM. Funding Acknowledgement Type of funding source: None

Objectives The objective of this clinical trial was to evaluate the long-term effect of endothelin receptor antagonism with bosentan on the morbidity and mortality of patients with severe chronic heart failure. Background Endothelin may play a role in heart failure, but short-term clinical trials with endothelin receptor antagonists have reported disappointing results. Long-term trials are lacking. Methods In 2 identical double-blind trials, we randomly assigned 1,613 patients with New York Heart Association functional class IIIb to IV heart failure and an ejection fraction Results Bosentan did not influence clinical status at 9 months in either trial (p = 0.928 and p = 0.263). In addition, 321 patients in the placebo group and 312 patients in the bosentan group died or were hospitalized for heart failure (hazard ratio [HR]: 1.01; 95% confidence interval [CI]: 0.86 to 1.18; p = 0.90). The bosentan group experienced fluid retention within the first 2 to 4 weeks, as evidenced by increased peripheral edema, weight gain, decreases in hemoglobin, and an increased risk of hospitalization for heart failure, despite intensification of background diuretics. During follow-up, 173 patients died in the placebo group and 160 patients died in the bosentan group (HR: 0.94; 95% CI: 0.75 to 1.16). About 10% of the bosentan group showed meaningful increases in hepatic transaminases, but none had acute or chronic liver failure. Conclusions Bosentan did not improve the clinical course or natural history of patients with severe chronic heart failure and but caused early and important fluid retention.

Background Recent meta-analyses support not resurfacing the patella at the time of TKA. Several different modes of intervention are reported for non-resurfacing management of the patella at TKA. Methods We have conducted a systematic review and meta-analysis of non-resurfacing interventions in TKA. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) study methodology and reporting system was adopted, utilising the PRISMA checklist and statement. Classes of patella interventions were defined as: 0.No intervention. 1.Osteophyte excision only. 2.Osteophyte excision, denervation, with soft tissue debridement. 3.Osteophyte excision, denervation, soft tissue debridement, and drilling or micro-fracture of eburnated bone. 4.Patellar resurfacing. A meta-analysis was conducted upon the pre- and post-operative KSS for each technique. Results Four hundred and twenty-three studies were identified, 12 studies met the inclusion criteria for the systematic review and eight for the meta-analysis. Two studies compared different non-resurfacing patellar techniques, the other studies used the non-resurfacing cohort as controls for their prospective RCTs comparing patellar resurfacing with non-resurfacing. The meta-analysis revealed no significant difference between the techniques. Conclusions We conclude that there is no significant difference in KSS for differing non-resurfacing patellar techniques, but further trials using patellofemoral specific scores may better demonstrate superior efficacy of specific classes of patella intervention, by virtue of greater sensitivity for patellofemoral pain and dysfunction. Level of evidence I

Secondary ion mass spectrometry (SIMS), focused ion beam (FIB) milling and Auger electron spectroscopy have been used to examine the composition and surface structure of uranium welded by an electron beam. Four characteristic areas of the metal surface were designated, these being: body (unaffected by the welding process), heat affected zone (HAZ), weld edge and weld. Surface composition to a depth of a few microns was determined using SIMS profiling, and direct thickness measurements of surface over-layers on the metal were made using FIB. Marked variations in both the thickness and composition of the over-layers were found when comparing the body/HAZ, weld edge and weld material. Additionally, numerous prismatic inclusions, approximately 5 μm 2 , were observed at the surface of the weld material. Auger and SIMS analyses indicated these inclusions were nitro-carbides. An increased concentration of these inclusions and other elemental impurities at the margins of the weld and within the HAZ indicated that during welding a segregation of impurities from the molten metal had occurred. The results are discussed in terms of processes considered to be occurring during welding and their implications in regard to corrosion in hydrogen atmospheres.

An improved nucleic acid amplification test (NAAT) to detect Chlamydia trachomatis infections, based on PCR amplification within its cryptic plasmid (CT1/CT2 Test) was developed. DNA was extracted from urogenital swabs and a 594-bp long DNA fragment from the cryptic plasmid (pCT) was amplified. The sensitivity and specificity of the CT1/CT2 Test were determined to be 100 and 99%, respectively, when directly compared with current amplification kit for sexually transmitted diseases (MPCR). Basic epidemiological data related to the patients attending gynecological and/or urological clinics are also provided. The overall prevalence rate in this group of patients suspected for C. trachomatis infection was determined to be about 95 per 1000 (88 and 107 per 1000 in females and males, respectively). It demonstrates that the CT1/CT2 Test is suitable for epidemiological screening and/or diagnostic practice.

The formation of UD3 on the surface of annealed uranium was induced at 320°C and 500 mbar pressure. The location of the deuteride (UD3) precipitates with respect to metal grain boundaries at the sample surface was studied by secondary ion mass spectrometry (SIMS) and focused ion beam (FIB) methods. Ion etching was used to remove the passive oxide layer on the sample surface and reveal the underlying structure of the metal grains. There is strong evidence for the formation of UD3 phases along the metal grain boundaries at the uranium surface.

Summary Aim: To define the views of junior house-officers (JHOs) concerning consent for general surgical conditions. Methods: Questionnaire-based descriptive study on two cohorts of JHOs, separated by 3 years of major national and local directives. Results: From the JHO perspective: (i) there has been a shift away from the JHO being the main signatory, (ii) many JHOs (58% in 2000; 47% in 2003) feel unsupported with respect to obtaining consent, (iii) knowledge concerning any consultant/unit's complication rates was poor (

DOI of original article: http://dx.doi.org/10.1016/j.knee.2015.10.012. ⁎ Corresponding author at: 7, Lydgate Street, Dorchester, Dorset DT1 3SJ, UK. Tel.: +44 7980 587648. E-mail address: findlayiain@hotmail.com (I. Findlay). Figure 1. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) flow diagram of each search strategy— (“knee replacement” OR “knee arthroplasty” AND “patellar resurfacing”OR “patellofemoral resurfacing”OR “patella retention”OR “patellar non-resurfacing”OR “patelloplasty”OR “patellaplasty”) and effect of application of inclusion/exclusion criteria.

Given the global nature of modern travel and the possibility of deployment to the African continent, it is conceivable that medical officers in the course of their general duties may be exposed to patients managed with traditional bone setting techniques. Whilst these techniques may prove effective for many, complications may still arise and their management may be challenging.

Conservation tillage is encouraged in southwestern Ontario by concern for soil erosion and compaction. The contribution of agriculture to eutrophication of the Great Lakes by P is also at issue. Soil loss and ortho-P transport were measured from a conventional and two conservation tillage treatments (zero and ridge tillage) from January 1988 to 30 Sept. 1990 to evaluate their impact on meeting Great Lakes water quality objectives for P. Sediment concentration from the poorly drained, Brookston clay loam (clayey, mixed, mesic Typic Haplaquolls), cropped to corn (Zea mays L.) was 2.1 times larger in surface runoff than tile discharge (0.20 g L -1 ) but tile discharge contributed 44 to 65% of the soil loss probably from preferential flow. Conservation tillage reduced average soil loss 49% from conventional tillage (899 kg ha -1 ). Conservation tillage increased ortho-P concentrations in runoff 2.2 times from conventional tillage (0.25 mg L -1 ). Orthophosphate transport decreased in the order zero>ridge>conventional tillage. Average ortho-P loss was 1.7 to 2.7 times greater from conservation than conventional tillage (559 g ha -1 yr -1 ). Subsurface drainage accounted for 55 to 68% of the ortho-P transported. Transport of total soluble P and total P (sum of sediment-attached P and soluble P, only measured in 1990) increased 2.2 and 2.0 times, respectively, with conservation than conventional tillage. Dissolved P accounted for 84 to 93% of the P transported from the three tillage treatments. Sediment-attached P constituted 7 to 16% of total P loss. Conservation tillage effectively reduced soil erosion but increased P loss.

Conservation tillage with residue management has been proposed as the most effective means to reduce soil deterioration in southwestern Ontario. Two conservation tillage treatments, ridge (RT) and zero (ZT) tillage, were compared with conventional moldboard plow (CT) tillage from 1987 to 1990 for atrazine [6-chloro-N-ethyl-N'-(1-methyethyl)-1,3,5-triazine-2,4-diamine], deethylatrazine [6-chloro-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine], and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] loss in surface runoff and tile discharge. Twenty-five to 44% of the annual rainfall resulted in total field runoff (surface runoff or tile discharge). Conservation tillage increased surface runoff 42% and decreased tile discharge 15% compared with conventional tillage, but total field runoff was the same from all treatments. Runoff events shortly after herbicide application produced the greatest herbicide concentrations and losses in both surface runoff and subdurface drainage. Averaged over years, herbicide concentration in surface runoff and tile discharge was, respectively, 1.3 and 1.8 times greater from conservation than conventional tillage. Conservation tillage altered the source of herbiciide loss compared with conventional tillage, but environmental factors after herbicide application were more important in determining total herbicide loss than tillage. Deethylatrazine was found in both surface runoff and tile drainage and accounted for 10 to 27% of combined atrazine and deethylatrazine loss

Although the use of cover crops and intercrops has been increasing, little information exists on effects these plant residues may have on soil microbial processes. Our objectives were to determine effects of several crop residues representing a range of C/N ratios (11.3-65.5) on mineralization, immobilization, denitrification, and dissimilatory NO 3 - reduction in Brookston clay loam with limiting and nonlimiting NO 3 - concentrations. Residues were obtained from two legumes, hairy vetch (HV; Vicia villosa L.) and red clover (RC; Trifolium pratense L.); two grasses, annual ryegrass (ARG; Lolium temulentum L.,) and reed canarygrass (RCG; Phalaris arundinacea L.); and corn (Zea mays L.). Nitrate consumption and NH 4 + , NO 2 - , NO, and N 2 O production were measured in soil with 10 g residue kg -1 in a gas flow system. In soil without added NO 3 - , during a 5-d aerobic incubation, 86% of the existing NO 3 - was immobilized with RC, 66% with corn, 44% with HV and ARG, and 41% with RCG. Intense immobilization in the RC and corn treatments limited the amount of NO 3 - available for denitrification, whereas during the subsequent anaerobic phase, only HV, ARG, and RCG stimulated denitrification. The enhanced net immobilization with RC was surprising because the C/N ratio for this residue was relatively low (15:1). Ammonium production was greatest with the HV residue. Nitrate addition to HV-amended soil further increased NH 4 + production with 91 mg N kg -1 being produced during a 5-d aerobic, 6-d anaerobic incubation. The nature of the residue-derived organic material is more important than simply the C/N ratio in regulating these microbial processes in these short-term incubations

To determine the inhibitory effect of O2 on denitrification in pure cultures of Pseudomonas fluorescens, measurements of net NO and N2O production rates, fNO and fN2O, under anaerobic conditions were compared to rates under partially aerobic conditions. Nitrate or NO2− solutions were injected into buffered suspensions and gaseous NO and N2O were sparged by constant flows of N2 carrier gas, or mixtures of N2 with measured small quantities of O2 (ca 6–60 Pa). Apparent Michaelis-Menten parameters were calculated from saturation kinetic plots obtained by monitoring net NO or N2O production following periodic addition of NO3−, NO2− or NO to suspensions of cells cultured aerobically in the absence of NO3−. With NO3− substrate added under anaerobic conditions the apparent KM=3,74± l.80mM, and under partially aerobic conditions KM =2.10 ± 0.54 mM; with NO2− substrate (anaerobic conditions) KM = 5.28±0.76 nM (partially aerobic conditions), KM=6.05± 1.30 μM, and with NO substrate, anaerobic conditions, KM = 7.3 ± 7.4 mu. The addition of O2 resulted in short-term transient effects indicating rapid and reversible inhibition of NO and N2O production. When O2 was present, NO2−, accumulated in greater amounts than observed under completely anaerobic conditions. The transient effects suggest that the reduction of NO2−, NO and N2O are each inhibited to increasingly greater extents by O2.

The analysis of genetic material is fundamental to many medical and scientific applications. These include diagnosis of genetic disorders from preimplantation embryos (1) prenatal diagnosis (amniocentesis and chorionic villus sampling [CVS]), forensic analysis (2) analysis of pathological specimens (3) paternity testing (4) disease screening, (e.g., antenatal cystic fibrosis screening (5) disease diagnosis, gene therapy (6) formation and analysis of transgeinc animals (7) and investigation of oncogenes (8). However, the major reason for the analysis of genetic material, particularly in medicine, is the diagnosis of genetic disorders.

A study was conducted to determine the effect of conservation (notillage and ridge tillage) and conventional (moldboard plow) tillage systems on NO j loss through surface runoff and tile drainage. Nitrate concentrations and total volume of surface runoff and tile drainage from conventional tillage (CT), no-tillage (NT), and ridge tillage (RT) all planted in continuous corn (Zea mays L.), and Kentucky bluegrass (BG, Poa pratensis L. ) treatments, were measured for 3 yr, 1989 to 1991. All corn tillage treatments received a total of 178.6 kg N ha~* annually during the growing season. The volume of water drained through the tiles in the corn tillage systems always exceeded the volume in surface runoff, typically by factors of 2 to 4. Tile drainage was greatest from the CT treatments, least from BG, and approximately equal from RT and NT treatments in 1989 and 1990. Concentrations of NO j in tile water from CT, RT, and NT treatments exceeded the maximum recommended safe limit for drinking water (10 mg N L~') in 79% of the leaching events, with flow-weighted concentrations between 12 and 17 mg N L ' in 1989 and 1990. Flow-weighted NOj concentrations were only 1.2 and 2.6 mg N L~' from BG in 1989 and 1990, respectively. The total NO; lost in tile water in 1989 was 18, 14, 14, and 1 kg N ha~' from the CT, RT, NT, and BG treatments, respectively, whereas in 1990 there were 29, 20, 20, and 3 kg N ha~' lost from the CT, RT, NT, and BG treatments, respectively. Nitrate losses in surface runoff were lower than in tile drainage, with maximums of 2.6 kg N ha ' for the RT and NT treatments in 1989 and 5.5 kg N hafor the RT treatment in 1990. In 1989 and 1990, both RT and NT treatments had greater yields and N uptake in grain than the CT treatment. A serious drought in 1991 limited corn yield, N uptake in grain, and NOj loss. N CONTAMINATION of surface runoff and tile drainage water from intensive agricultural production systems has become a serious environmental and economic concern. Contaminated waters contribute to eutrophication of lakes and streams. In addition, since some municipalities use surface waters for human consumption, the NOf concentration in these waters must be < 10 mg N L~. Nitrate can be readily converted to NOf in the human body, and has been implicated in two major health problems: blue-baby syndrome (methaemoglobinaemia) and stomach cancer. Kladivko et al. (1991) conducted a drainage research study on a Clermont silt loam (fine-silty, mixed, mesic Typic Glossaqualf) in Indiana. Nitrate concenC.F. Drury, W.I. Findlay, and J.D. Gaynor, Research Station, Agriculture Canada, Harrow, ON, Canada NOR 1GO; and D.J. McKenney, Dep. of Chemistry and Biochemistry, Univ. of Windsor, Windsor, ON, Canada N9B 3P4. Received 13 July 1992. *Corresponding author. Published in Soil Sci. Soc. Am. 3. 57:797-802 (1993). trations in tile drainage water under a corn crop fertilized with 285 kg N hawere seldom

Given the global nature of modern travel and the possibility of deployment to the African continent, it is conceivable that medical officers in the course of their general duties may be exposed to patients managed with traditional bone setting techniques. Whilst these techniques may prove effective for many, complications may still arise and their management may be challenging.

The preimplantation diagnosis of a HbSA-globin transgene in biopsied trophectoderm cells and blastomeres in embryos using a transgenic mouse model for the trait of human sickle-cell anaemia has been undertaken. A sensitive procedure was developed for the amplification of the human beta-globin gene sequence flanking the sickle mutation. Polymerase chain reaction (PCR) assays were undertaken on one to five biopsied trophectoderm cells and isolated blastomeres of the preimplantation mouse embryo. After biopsy the blastocysts were cultured whilst the cells were analysed for the presence of the transgene, and a high proportion (82-91%) were viable as assessed by the presence of a blastocoele cavity within a 5-h period. The majority of the biopsied cultured blastocysts were frozen and used to confirm the diagnosis; 90 biopsied cultured blastocysts were transferred to pseudopregnant recipients and 34% established pregnancy. Material from day 13.5 post-coitum fetuses was also used to confirm the original diagnosis. The time (4-5 h) required to carry out the analysis obviates a need for extended culture or cryopreservation of the biopsied embryo. In individual experiments under optimal conditions, the presence of the transgene in biopsied cells was detected with 100% accuracy, and the PCR analysis was sensitive at the 1-cell level. The overall success rate of diagnosis and confirmation of the presence or absence of the human beta-globin sequence in the biopsied embryo was 70%. Over the entire experimental period (14 months) DNA contamination from a variety of sources did occasionally occur; the methods used to overcome this problem are discussed.

Three tillage practices, conventional, zero, and ridge tillage, were compared for water quality in the first three years of tillage establishment. The tillage treatments were on a poorly drained, Brookston clay loam soil of

This study was designed to determine the effects of water and O2 on the speciation of denitrification gases (NO and N2O). Nitric oxide was found to be the principal end product from soil incubated under low-moisture conditions, whereas the relative amount of N2O increased under wetter moisture regimes. The total amount of NO plus N2O produced increased with increasing water content for the Brookston clay loam (fine-loamy, mixed, mesic Typic Argiaguoll), whereas it peaked at 150 g kg(15%) water content with the Fox sandy loam (fine-loamy over sandy or sandy or sandy-skeletal, mixed, mesic, Typic Hapludalf). The decrease in NO plus N2O at higher water contents was probably the result of the subsequent reduction of N2O to N2 in the Fox sandy loam soil. The residence time of the denitrification gases in the soil increased with increasing water content, hence facilitating the subsequent conversions of NO to N2O and N2. The thickness of the water film surrounding the microbes affected both the diffusion of O2 through the water and into the microbes as well as the diffusion of denitrification gases (NO, N2O, and N2) from the microbes into the atmosphere. In the sandy loam soil, O2 content and soil water affected both the amount and species of evolved denitrification gases. Oxygen was more effective in decreasing NO production at lower than at higher water contents. N OXIDE, N2O, and N? are gaseous products of nitrification and denitrification processes and NO and N2O are important atmospheric trace gases. Nitric oxide (and NO2) in the troposhere catalyzes photochemical O3 production, contributes to formation of acid rain and controls the formation of hydroxyl radicals, the major reactant for a number if atmospheric constituents (Parrish et al., 1990). Nitrous oxide is an important greenhouse gas and the major source of stratospheric NO, one of the predominant catalysts for O3 removal. The molar ratio of NO to N2O was found to be > 1 in nitrifier cultures, whereas it has been found to be < 1 for cultures of denitrifiers (Anderson and Levine, 1986). This may be the result of the influence of O2 on denitrification. Nitric oxide production was found to be independent of O2 partial pressure (pO2) with nitrifiers, whereas N2O production was inversely related to pO2 for the denitrifiers. The primary effect of water on denitrification in aerobic and partially aerobic soils is to restrict O2 levels by reducing the air-water interfacial area within air-filled pores (Skopp, 1985) thus producing the anaerobic condition thought to be required for denitriC.F. Drury and W.I. Findlay, Research Station, Agriculture Canada, Harrow, ON, Canada NOR 1GO; and D.J. McKenney, Dep. of Chemistry and Biochemistry, Univ. of Windsor, Windsor, ON, Canada N9B 3P4. Received 21 Feb. 1991. *Corresponding author. Published in Soil Sci. Soc. Am. J. 56:766-770 (1992). fication. Oxygen diffusion rates are some four orders of magnitude slower in water than in the gas phase and hence O2 concentraton at the microbial cell is regulated by water content (Klemedtsson et al., 1988). Relatively small changes in water content in soils may directly influence rates of denitrification. Many field studies have shown that intense denitrification activity often follows heavy rainfall or flooding periods when aeration of the soil is severely restricted (Sexstone et al., 1985). Excess water not only limits O2 diffusion into the soil, but also affects the movement, distribution, and relative proportion of evolved denitrification gases. For example, Mahendrappa and Smith (1967) reported that a 10% increase in water content above field capacity in fully anaerobic soils markedly increased the amount of N2O converted to N2 with little effect on NO 3 disappearance. Water contents above these levels further decreased rates of N2O production. The objective of this study was to investigate the physical effects of water on NO and N2O production under conditions favoring denitrification, using a gasflow column approach (McKenney et al., 1982). With this technique, NO and N2O are rapidly scrubbed from the water and pore space in soil columns by a continuous flow of an inert carrier gas, enabling us to determine the production rates of these denitrification gases. In addition, the combined effect of O2 and soil water content on NO production was investigated. MATERIALS AND METHODS Anaerobic Nitric and Nitrous Oxide Production at Varying Water

This article describes the development of an interactive videodisc program to support professional education in the field of cancer for the primary health care team. Based on a survey of needs, it concentrates on common symptoms and their control, and problems in communication. The educational approach adopted was chosen on the basis of an extensive consideration of the needs, and what was felt most appropriate for adult learners. Plans were carefully reviewed at each stage, with external advisers, and the prototype system independently evaluated in four sites before completing the package. With financial backing from the 'Europe against Cancer' initiative of the European Commission, and close cooperation with national practitioners, Dutch, German, Greek and Portuguese versions of the package have been developed. Local differences in practice are taken into account and translations of key aspects are provided.

Maintaining long-term soil productivity requires development of cropping systems that provide maintenance or improvement in soil structure and an understanding of associated rhizosphere microbial populations. The objectives of this study were to determine the effects of several crops on soil biomass C and biomass N contents, their within-season variability, and the relationships between changes in soil biomass C, biomass N, and soil structure on a Brookston clay loam soil (fine-loamy, mixed, mesic Typic Argiaquoll). Soil microbial biomass C, biomass N, and soil-structure parameters (wet aggregate stability [WAS], organic carbon [OC], dry aggregate mean weight diameter [MWD], bulk density, and total and air-filled porosity) were measured during the third year of corn (Zea mays L.), soybean (Glycine max [L.], Merr.) alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), reed canarygrass (Phalaris arundinacea L.), orchardgrass (Dactylis glomerata L.), and no-crop (bare, covered, and shaded) plots at monthly intervals (June, July, August, and September). Reed canarygrass resulted in greater biomass-C contents than both the corn and soybean at all four sampling dates. Soil biomass C under alfalfa was significantly greater than under corn and soybean for both the first and last sampling dates. Forage species did not affect the soil biomass-N content. No consistent effects of the no-crop treatment on biomass C or biomass N were observed between sampling dates. Biomass C was significantly correlated with WAS, OC, and MWD for the cropping treatments. Wet aggregate stability was negatively correlated with soil water content for both the no-crop and cropping treatments, indicating that improvements in structure were not solely the result of the cropping treatments and associated rhizosphere populations. Reed canarygrass resulted in greater soil biomass C/N than the alfalfa, corn, and orchard grass plots, suggesting that fungal activity, and therefore soil structure, may be preferentially enhanced in the presence of reed canarygrass. This study demonstrated the influence of forage species and seasonal variability on concurrent changes in microbial biomass and soil structural properties.

Methods previously used for the biopsy of preimplantation mouse embryos have been applied to individual 'spare' human embryos. Early cleavage-stage human embryos have been cultured and individual blastomeres removed following zonae thinning or drilling. Embryos have also been cultured to the blastocyst stage for the biopsy of three to five trophectoderm cells. Both the biopsied embryo and the biopsied cells have been allowed to develop and/or grow in vitro.

The relationships between denitrification, soil microbial biomass and selected soil properties were investigated in 13 soils which varied in physical and chemical properties. It was hypothesized that estimates of biomass C may be directly related to the background (unamended) denitrification rates. Denitrification potential (with C and NO−3 amendments) was also compared to biomass C and the indigenous soil properties. The background and potential denitrification rates were measured in these soils during 75 h of anacrobiosis. Background denitrification was highly correlated with biomass C. organic C content and moisture content at field capacity (−33 kPa). Soil organic C was also highly correlated with microbial biomass C. Nitrate was not limiting for most soils as in all but two soils the residual NO−3 content following incubation exceeded 10mg N kg−1. Hence. NO−3 concentration was not strongly correlated with the background denitrification rate. The denitrification potential was 5 times greater than background denitrification. In our study, C was the factor limiting denitrification. Further, microbial biomass appeared to be a sensitive indicator of both soil C content and background denitrification. There was no significant relationship between any of the other soil chemical and physical properties measured and the denitrification potential.

The effect of chloroform fumigation on O 2 inhibition of denitrification was evaluated in non-fumigated, fumigated and sterile soil with 0, 1, 2. 3 or 6% added O 2 using the C 2 H 2 inhibition technique. Chloroform fumigation was used to lyse microbes and thereby release nitrate reductase which may decrease O 2 inhibition. With the fumigated treatment, soil samples were exposed to chloroform for 24 h followed by evacuation, whereas a CHCl 3 saturated atmosphere was maintained during the incubation in the sterile soil treatment. Nitrous oxide. CO 2 and O 2 in the headspace of incubation containers were measured over 10d. Denitrifiers apparently recolonized the fumigated soil within 12 h after chloroform removal. Oxygen inhibited denitrification in fumigated and non-fumigated soils. Oxygen consumption and CO 2 production were greater in fumigated than in non-fumigated soil samples as a result of the additional carbon from lysed microbes. Nitrite reductase appeared to be more sensitive to O 2 than nitrate reductase.

The culture of human preimplantation embryos from the 1-cell to the morula/blastocyst stage of development is not satisfactory at present. The success of various IVF laboratories ranges from 18 to 23%, therefore there is a requirement for improvement in the standard conditions used to culture the embryo. Using a limited number of 'spare' human embryos which were donated for research, in-vitro studies have been undertaken using various culture media. The results show that a significant improvement in viability is achieved using Ham's F-12 medium compared with other media presently used for culturing embryos.

To define the views of junior house-officers (JHOs) concerning consent for general surgical conditions.Questionnaire-based descriptive study on two cohorts of JHOs, separated by 3 years of major national and local directives.From the JHO perspective: (i) there has been a shift away from the JHO being the main signatory, (ii) many JHOs (58% in 2000; 47% in 2003) feel unsupported with respect to obtaining consent, (iii) knowledge concerning any consultant/unit's complication rates was poor (30%), (iv) knowledge concerning complication rates for several paradigm procedures was also poor, though it improved from 2000 to 2003, (v) there is no formal training in consent.Despite the JHO group of 2003 outperforming that of 2000, there is major scope for improvement from patient, legal, educational and risk-management perspectives.

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Vesnarinone, a phosphodiesterase inhibitor, prolongs cardiac action potential duration by inhibiting the delayed rectifier K(+) current, I(K). We examined the effect of this agent on human ether-a-go-go related gene (HERG) and KvLQT1/minK K(+) channels heterologously expressed in human embryonic kidney 293T cells with the whole-cell patch-clamp technique. HERG channel current was inhibited by vesnarinone in a concentration-dependent manner, whereas KvLQT1/minK current was hardly affected by the drug. The inhibition of HERG current by vesnarinone became more prominent and faster as the membrane potential was more depolarized. The properties of inhibition could be described by a first order reaction between the drug and the channel that was apparently independent of HERG channel gating. Although the unbinding rate constant of the drug was constant, the apparent binding rate constant increased as the membrane was more depolarized and the drug concentration was raised. This model also could explain the fast recovery from the drug's effect at hyperpolarized potentials and its rate-dependent inhibition of HERG. Therefore, the effect of vesnarinone on the HERG-K(+) current could be adequately described by a simple kinetic model of drug-channel interaction.

Although conventional polymerase chain reaction (PCR) was the first method used for sexing in preimplantation genetic diagnosis, fluorescent in situ hybridization (FISH) has become the method of choice. Recently two new techniques, primed in situ synthesis (PRINS) and fluorescent PCR, have been developed. This study compares the reliability and accuracy of these four techniques in single cells.In buccal cells, fluorescent PCR and FISH had similar reliability (94 and 93%) and accuracy (97 and 96%) rates. The reliability and accuracy of PRINS (91 and 25%) and conventional PCR (79 and 89%) were lower. In human blastomeres, FISH and fluorescent PCR had similar reliability (100%, 717; 95%, 190/201) rates. Accuracy rates were 71% (517) and 99% (188/190) for FISH and fluorescent PCR, respectively, however, too few blastomeres were analyzed by FISH for meaningful comparison. However, when these data are compared with published data, the method of choice for blastomere sexing appears to be fluorescent PCR.Flouroscent PCR has major implications for PGD.

Prenatal diagnosis of fetal trisomies is usually performed by cytogenetic analysis on amniotic fluid. This requires lengthy laboratory procedures and high costs, and is unsuitable for large scale screening of pregnant women. An alternative method, which is both rapid and inexpensive and suitable for diagnosing trisomies even from single fetal cells, is the fluorescent polymerase chain reaction using polymorphic small tandem repeats (STRs). In this paper we present the preliminary results of a larger study comparing parallel prenatal diagnoses of trisomies 21 and 18 using cytogenetics with quantitative fluorescent polymerase chain reaction using STR markers. The results obtained by the two techniques were concordant in all cases. This is the first study reporting significant numbers of prenatal diagnoses using the quantitative fluorescent polymerase chain reaction. We believe that further studies on greater numbers of samples will determine the absolute reliability of this technique. These results also provide a model for diagnosis of trisomy from single fetal cells isolated from maternal blood.

Prenatal diagnosis (chorionic villus sampling (CVS) or amniocentesis) is performed at a relatively late stage of pregnancy (11-18 weeks). Such tests have significant disadvantages including increased risk of miscarriage and delay before results are known. Earlier prenatal diagnosis (11 weeks) has been discontinued because of the risk of fetal abnormalities. Recently fetal cells have been recovered from the coelomic cavity at 7-12 weeks gestation (coelocentesis). This study has established that highly sensitive fluorescent polymerase chain reaction (PCR) can provide rapid (4-5 h), reliable and accurate multiple genetic diagnoses (sexing and single-gene diagnosis) from coelomic cells. As prenatal diagnosis has a significant risk of contamination, we have also shown that coelomic cells can be simultaneously DNA fingerprinted to determine that contamination has not occurred. This earlier method of prenatal diagnosis would be very valuable, as it may overcome some problems of later conventional prenatal diagnosis and allow reassurance/treatment to be undertaken at a much earlier stage. Successful application of these techniques may supersede alternative methods of prenatal diagnosis. Although these techniques appear very promising, extensive clinical trials must be undertaken to determine safety of coelocentesis, diagnostic reliability and accuracy in a clinical setting.

To determine the effects of atenolol, nifedipine and their combination on exercise parameters and ambulatory ischaemic activity in patients with mild chronic stable angina.Multicentre, multinational study involving 608 patients from 69 centres in nine countries.Placebo washout followed by double-blind parallel-group study comparing atenolol 50 mg bd, nifedipine SR 20 mg bd, and their combination. Patients underwent maximal exercise testing using either a bicycle (n = 289) or treadmill (n = 319) and 48 h of ambulatory ST segment monitoring outside the hospital environment at the end of the placebo washout period and after 6 weeks of active therapy.Both medications alone and in combination caused significant improvements in exercise parameters and significant reductions in ischaemic activity during daily activities, when compared with placebo. There were, however, no significant differences between groups, for any of the measured ischaemic parameters although combination therapy resulted in a greater fall in resting systolic and diastolic blood pressure than either treatment alone.In the management of mild chronic stable angina there appears to be little advantage gained from using combination therapy for ischaemia reduction.

Previously the diagnosis of sex and cystic fibrosis status has been studied on single cells using the polymerase chain reaction (PCR). It has been suggested that allelic drop-out (PCR failure of one allele) and/or preferential amplification (hypo-amplification of one allele) may contribute to poor reliability and misdiagnosis, although this remains controversial as some reports suggest that allelic drop-out does not occur. We investigated an improved method of diagnosing sex and cystic fibrosis in single cells using a new technology (fluorescent PCR) to determine the base level of PCR artefacts (allelic drop-out and preferential amplification) which, in combination with improved sensitivity, should improve PCR reliability and accuracy. Fluorescent PCR gives high reliability (approximately 97%) and accuracy rates (approximately 97%) in somatic cells for both sex and cystic fibrosis diagnosis and its lower detection threshold allows allelic drop-out and preferential amplification to be easily distinguished. We also achieved high reliability and accuracy in diagnosing cystic fibrosis in human blastomeres. This study confirms earlier reports of both allelic drop-out and preferential amplification in single cell analysis. We demonstrate that both allelic drop-out and preferential amplification occur in somatic cells and suggest these are separate phenomena. Preferential amplification appeared common in single cell PCR while allelic drop-out apparently occurred at random in each allele. Preferential amplification was mainly amplification of the larger allele. We suggest that some inaccuracy/misdiagnosis may be due to both preferential amplification as well as allelic drop-out. Other findings were variability in drop-out between PCR and that amplification of signals from human blastomeres may be linked to embryo quality. We suggest that allelic drop-out is dependent on the number of cells within the sample.

(2003). The ergonomics of safe needle disposal following venous cannula insertion—in search of a solution to a problem. Southern African Journal of Anaesthesia and Analgesia: Vol. 9, No. 3, pp. 15-16.

A multicentre epidemiological study to detect the prevalence of myocardial ischaemia in hypertensive left ventricular hypertrophy (LVH) was performed in 188 asymptomatic male hypertensives (131 treated). The mean age was 55 (range 40-82) years with blood pressure (BP) > or = 160/100 mmHg or a systolic BP > or = 180 mmHg. The participants were screened with echocardiography, and left ventricular hypertrophy (LVH), defined as LV mass index (LVMI) > or = 130 g.m-2, was found in 127 (68%), of whom 95 were on antihypertensive treatment. Patients with LVH underwent a maximal bicycle ergometer exercise test and significant ST depression, indicating possible stress-induced ischaemia, was found in 29 men (23%). These subjects were subjected to exercise thallium-201 scintigraphy, which was normal in 14 but showed reversible perfusion defects in 15. Thus, a high prevalence of LVH (70%) was detected in male hypertensives selected only on age and BP. In addition, although chest pain on exertion excluded patients from entry, a substantial portion had signs of ischaemia (23% on exercise ECG alone, and in 52% confirmed by thallium scan). The prevalence of these risk factors should be considered when evaluating hypertensive patients.

2-(3,4-Dihydro-2,2-dimethyl-6-nitro-2H-1,4-benzoxazin-4-yl)pyridin e N-oxide (YM934) is a newly synthesized benzoxazin. The effects of YM934 on ATP-sensitive K+ (KATP) channels in guinea pig cardiac ventricular myocytes and in an insulin-secreting cell line, HIT T15 beta-cells, were examined using the gigaohm-seal patch-clamp techniques. Under the whole-cell clamp condition, YM934 induced in ventricular myocytes a time-independent, glibenclamide-sensitive K+ current in a concentration-dependent fashion (EC50 = approximately 3 microM). On formation of inside-out patches in ATP-free solution, the KATP channel current abruptly appeared and then ran down. YM934 was applied to inside-out patches before, during and after channel "run-down." Because nucleoside diphosphates, such as uridine diphosphate (UDP), can induce channel openings after complete run-down, the effects of YM934 on the UDP-induced channel openings were also examined. Before run-down, YM934 enhanced KATP channel activity by decreasing the sensitivity of channels to intracellular ATP. YM934 also enhanced the partially run-down channel, even in the absence of ATP. After run-down, YM934 had no effect but could enhance the UDP-induced KATP channel openings. These effects of YM934 on cardiac KATP channels were similar to those of pinacidil and lemakalim. In HIT T15 beta-cells, 100 microM YM934 was ineffective in both cell-attached and inside-out patch configurations, suggesting the tissue-specific nature of the action of this novel K+ channel opener.

The effects of the sulphonlyurea drugs glibenclamide and tolbutamide were tested upon ATP-sensitive K+ channels activated by dinitrophenol or carbonyl cyanide p-(trifluoromethoxy)-phenylhydrazone (FCCP) in ventricular myocytes isolated from rat hearts. In whole-cell current recording, 1 microM glibenclamide or 1 mM tolbutamide totally but only transiently inhibited the K+ current activated by dinitrophenol or FCCP. In cell-attached membrane patches, 1 to 100 microM glibenclamide initially inhibited the activation of ATP-sensitive K+ channels induced by dinitrophenol or FCCP, but failed to prevent the activation of these channels during contracture. Myocyte contracture induced by caffeine or Ca++ entry during K+ depolarization did not activate ATP-sensitive K+ channels. In excised membrane patches, 1 to 10 microM glibenclamide did not block completely opening of ATP-sensitive K+ channels. Neither intracellular ADP nor phosphorylable substrate were able to reliably influence the effect of glibenclamide. It is concluded that sulphonylurea drugs, otherwise highly effective blockers of this type of ion channel, were no longer able to inhibit the opening of ATP-sensitive K+ channels during the final stages of metabolic stress. These channels could therefore be responsible for both the glibenclamide-sensitive and glibenclamide-insensitive phases of K+ loss during cardiac ischemia.

Cultured mouse embryonic stem (ES) cells are used for both in vitro and in vivo studies. The uncommitted pluripotent cells provide a model system with which to study cellular differentiation and development; they can also be used as vectors to carry specific mutations into the mouse genome by homologous recombination. To ensure successful integration into the germ line, competent totipotent diploid ES cell lines are selected using a cell injection bioassay that is both time consuming and technically demanding. The prolonged in vitro culture of rapidly dividing ES cells can lead to accumulated changes and chromosomal abnormalities that will compromise the biological function and abrogate germ line transmission of chimeric mice carrying novel genetic mutations. Such in vitro conditions will vary between individual laboratories; for example, differences in the serums used for maintenance. Using a number of different criteria we attempt in this paper to define the parameters that we found to be key factors for optimization of the biological potential of established ES cell lines. The successful integration into the germ line is dependant on acquiring or deriving a competent totipotent mouse ES diploid cell line. In this paper parameters and criteria are defined which we found to be key factors for the optimization of the biological potential of established ES cell lines.

The effect of pH was tested upon the inhibition of ATP-sensitive K+ (KATP) channels caused by the sulphonylurea drugs tolbutamide and glibenclamide. KATP channels and currents (I-KATP) were activated with SR 44866 in ventricular myocytes isolated from guinea pig hearts. Modification of either external or internal pH had little effect upon the background K+ current (IK1). External pH had no consistent effects upon I-KATP. The application of NH4Cl inhibited I-KATP and its withdrawal caused a slight rebound activation. Compared with the results obtained at pHo 7.4, inhibition of I-KATP by the sulphonylurea drugs was enhanced at pHo 6.5 and reduced at pHo 8.4. The kinetics of the recovery of I-KATP was independent of pHo. Neither internal pH 6.5 nor NH4Cl had any effect upon sulphonylurea-induced inhibition of I-KATP. The dose-response curves for inhibition of I-KATP at different pHo's were found to coincide when plotted for the unionized concentrations of the drugs. It is concluded that it is the unionized forms of the sulphonylurea drugs which are responsible for closure of KATP channels in cardiac muscle. In consequence, extracellular acidification during ischemia will increase the effective concentration of glibenclamide and may be responsible for the cardiovascular disorders associated with this treatment in noninsulin-dependent diabetics.

The effects of the sulphonylurea drug glibenclamide were tested upon ATP-sensitive K+ (KATP) channels activated by 20 microM SR 44866 in isolated ventricular myocytes from guinea pig hearts. Glibenclamide inhibited the openings of KATP channels in both cell-attached and excised inside-out membrane patches. Glibenclamide inhibited the whole-cell KATP current (I-KATP) with an EC50 of 6 nM and Hill Coefficient of 1.26. The kinetics of the onset of inhibition of I-KATP were complex and dose-dependent. The recovery of I-KATP from inhibition was largely dose-independent. The application of glibenclamide for short periods of time was followed by the continued development of inhibition. These results suggest that the cell was loaded with the drug before it interacted with the KATP channel. It is proposed that the sulphonylurea receptor site is to be found in the lipid phase of the membrane. In consequence critical factors involved in the sulphonylurea drug-induced inhibition of KATP channels will include the rates of drug absorption into and exit from the membrane lipid. That sulphonylureas will be concentrated in the membrane lipid suggests that the EC50 value for channel inhibition does not represent the true affinity of the drugs for their receptor.

The ATP-sensitive K channel opener, SR 44866, was applied to intact extensor digitorum muscle of the mouse. Electrically stimulated maximal twitch contractions of the muscle were decreased by SR 44866 with a KD of 7.4 microM and a Hill coefficient of 1.2 at 34 degrees C. The effect of SR 44866 was antagonized by glibenclamide and reduced at 24 degrees C. We suggest that these results represent the consequence of activation of ATP-sensitive K channels in mammalian skeletal muscle.