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Background: The combination of pepsinogen, gastrin-17 and anti-H. pylori antibodies serological assays (panel test) is a non-invasive tool for the diagnosis of atrophic gastritis. However, the diagnostic reliability of this test is still uncertain. Aim: To assess the diagnostic performance of the serum panel test for the diagnosis of atrophic gastritis. Methods: Medline via PubMed, Embase, Scopus, Cochrane Library databases and abstracts of international conferences proceedings were searched from January 1995 to December 2016 using the primary keywords “pepsinogens,” “gastrin,” “atrophic gastritis,” “gastric precancerous lesions.” Studies were included if they assessed the accuracy of the serum panel test for the diagnosis of atrophic gastritis using histology according to the updated Sydney System as reference standard. Results: Twenty studies with a total of 4241 subjects assessed the performance of serum panel test for the diagnosis of atrophic gastritis regardless of the site in the stomach. The summary sensitivity was 74.7% (95% confidence interval (CI), 62.0-84.3) and the specificity was 95.6% (95%CI, 92.6-97.4). With a prevalence of atrophic gastritis of 27% (median prevalence across the studies), the negative predictive value was 91%. Few studies with small sample size assessed the performance of the test in detecting the site of atrophic gastritis. Conclusions: The combination of pepsinogen, gastrin-17 and anti-H. pylori antibodies serological assays appears to be a reliable tool for the diagnosis of atrophic gastritis. This test may be used for screening subjects or populations at high risk of gastric cancer for atrophic gastritis; however, a cost-effectiveness analysis is needed.

Better criteria for selecting cultivars for their ability to grow well on low-P soils could reduce waste of fertilizer P. The objective of this study was to quantify and determine the reproducibility of two crop parameters (A and K m ) responsible for differences in the response of 12 Brassica oleracea L. genotypes to P supply. Modified Michaelis-Menten equations were fitted to shoot dry weight responses to P supply for each genotype in each of three glasshouse and three field experiments. One of the fitted parameters (A) defined the maximum shoot dry weight that could be obtained with ample P, and the other (K m ) defined the efficiency of root P-uptake as the concentration of extractable soil P in the rooting medium at which growth was half the maximum. The equations fitted the data well. Ranking and regression analyses showed that intergenotypic differences in A were considerable, and reproducible, but that differences in K m were small. Thus, B. oleracea genotypes yielding most on a P-sufficient soil will also yield most on a P-deficient soil. However, both the maximum yield (A) and the efficiency of root-P uptake (K m ) vary considerably between different vegetable crops. Thus, a graphical procedure to select crops for highest yields on low-P soils, on the basis of a comparison of A and K m values, is described.

Aim: To use Prescribing Analysis and Costs data to investigate factors associated with differences in rates of nonsteroidal anti-inflammatory drug prescribing in Nottingham general practices. Results: Poisson regression analysis revealed that the Age, Sex and Temporary Resident Prescribing Unit Index was the largest identifiable influence; larger practice size and a higher index of deprivation were also significantly associated with lower prescribing, whilst the number of partners was associated with higher levels of prescribing. However, even after correcting for the influence of age, sex and temporary residents, there was an 5.9-fold variation in rates of prescribing. A similar Poisson regression analysis to identify factors associated with admission to hospital with ulcer bleeding in the elderly over the preceding 57 months identified the rate of nonsteroidal anti-inflammatory drug (NSAID) prescribing as the only significant influence. Conclusion: The data are compatible with 1 hospital admission per 2823 NSAID prescriptions (95% confidence intervals 2098–8110) and they emphasize the need for strategies to reduce levels of NSAID prescribing.

SUMMARY The development of soil science has, in the past, been largely driven by the need to improve agricultural production. It is an applied science. Soils and soil processes have had a profound impact on the development of agriculture, and civilization, throughout the ages. Mistreatment of soil has, over the millennia to the present day, been responsible for horrific human tragedy. The most pressing challenge to soil science is to devise ways of improving food production, at minimum cost, in those areas of the world where food shortages are most acute. The new era of reducing price support for major agricultural commodities will increase competition in the EC and elsewhere. It will become imperative to improve efficiency of crop production, especially by the introduction of novel techniques, if arable and horticultural cropping in the UK is to flourish. Soil science is becoming increasingly important in assisting governments to develop policies and in assisting commercial organizations to screen and introduce new chemicals. There is a wide range of environmental and pollution problems that demand inputs from soil science. They include industrial degradation of soil, entry of toxic materials into the food chain, waste disposal, industrial contamination of the atmosphere and the sub-sequent effects on soil and vegetation, forest decline, and the improvement of industrially damaged areas to attract new industries and reduce unemployment. Far greater use should be made of soils information in urban and rural planning and in building design as, at least in some countries, this practice has resulted in considerable financial savings. Advances in theory, measurement and computing are revolutionizing soil science and will greatly facilitate the application of the subject to practical problems.

A general method for the synthesis of functionalized pyridazinylboronic acids/esters is described involving a directed ortho metalation (DoM)boronation protocol (Schemes 1 and 2). A comprehensive study of the reactivity of the C−B bond in palladium-catalyzed cross-couplings with aryl/heteroaryl halides is presented. Aryl-/heteroarylpyridazines are thereby obtained in synthetically viable yields (typically 40−75%) although in some cases competing protodeboronation has been observed. A series of pyridazin-3(2H)-one derivatives, including 4,6-diaryl/heteroaryl derivatives, have been obtained from the corresponding 3-methoxypyridazines in straightforward procedures (Schemes 3 and 4). Several X-ray crystal structures of aryl-/heteroarylpyridazines and derived pyridazin-3(2H)-one derivatives are reported. These multi-ring systems are of considerable interest in contemporary N-heterocyclic chemistry.

I would like to say how immensely honoured I feel to have been invited to give the twelfth Blackman Lecture. Professor Blackman was a man of immense distinction. Although he is perhaps best known for his truly outstanding contributions to Weed Science and Plant Ecology, he had very wide interests, some of which are directly relevant to the subject of this lecture. He introduced and developed new mathematical methods for interpreting field data (e.g. Blackman, 1935, 1942) and wrote important papers that aid understanding of how factors, such as light intensity and mineral nutrition affect the development, growth and composition of different species (e.g. Blackman and Templeman 1940; Blackman and Rutter 1946). Other members of the Blackman family also have a very distinguished place in Plant Science and in the context of this lecture it is appropriate to mention that Professor F. F. Blackman enunciated the very celebrated concept of limiting factors which is now universally accepted as a basic axiom in Plant Nutrition. Plant nutrient stress, of one form or another, limits crop yield in much of the world. Yet it is frequently very difficult to discern the causes of stress in a given field or to forecast the best ways of relieving it at minimum cost. These difficulties are a consequence of the variability in soil and weather conditions and of the associated problems in interpreting the results of field experiments. Often the results of well-planned field experiments covering a range of conditions are interpreted by statistical procedures with a disappointing outcome. The main weakness of this method of interpretation is that it relies on equations with no foundation in terms of accepted concepts of the phenomena they seek to represent. It makes virtually no use of any of the principles that have been evolved in any branch of soil science or plant nutrition. Opportunities for overcoming these shortcomings are made possible by the recent development of quantitative theories, expressed as equations, for key processes influencing nutrient response. They appear to be of wide applicability. The main purpose of this lecture is to discuss some of these theories and to show how they may be generally applied to improve the reliability of practical advice to the farmer.

Summary It is shown that, under certain conditions, the increase in carbon dioxide partial pressure is proportional to the drop in oxygen partial pressure in the gas phase in fallow soils. The principal assumptions are that respiration is unaffected by lowering of oxygen partial pressure until very low levels are reached, and that the respiration quotient is constant. Previously reported measurements of the composition of gases extracted from soil are consistent with the theory.

Summary Most of the requirements of roots for oxygen were met by oxygen from the air entering the leaves and travelling through the plants to the roots in oxygen-free media. The amount of oxygen supplied in this way decreased proportionately with rise in oxygen partial pressure at the root surface. Although roots offered a considerable barrier to the passage of oxygen out of them, experiments in which transport from the aerial parts was prevented indicated that the roots could obtain almost all the oxygen they required from the surrounding media provided the oxygen partial pressure at the root surface exceeded the low value of 0.05 atmospheres. These results were obtained by means of a new experimental technique which enabled the effect of oxygen partial pressure at the root surfaces on oxygen uptake and root elongation to be studied. It was based on circulating a small volume of nutrient solution around roots in a gas-free enclosed system sufficiently rapidly for the partial pressure in the solution to be almost the same as at the root surfaces.

Summary The entry of oxygen into various organs and the transport of oxygen through plant tissues was studied. Seedlings had their roots embedded in agar-gel to exclude oxygen. The gas atmosphere around a part of the plant was changed from nitrogen to oxygen and the subsequent increase in oxygen concentration at a point on the root surface was measured. Changing the atmosphere around the stems and leaves induced rises in oxygen concentrations throughout the length of the roots to the root tips. An equation derived by assuming that transport was by gaseous diffusion and was large in comparison with metabolic uptake, fitted the increases in oxygen concentration at points on the roots within 3 cm of the stems, but not at the root tips. The discrepancy was accounted for by the greater value of metabolic uptake relative to oxygen transport at the root tips than near the stems. Thus all the results were consistent with oxygen diffusing through gas spaces within the plants. Removing all the leaves restricted the entry of oxygen into the aerial portions of the plants, but the extent to which it did so was reduced by subjecting the seedlings to water stress and was less with old than with young seedlings. Excising the leaves was considered to release cell sap which blocked the gas channels. Exposure of either the stem or a segment of root to oxygen resulted in a small amount of oxygen being transported along the roots. Oxygen transport from the aerial portions of the plant to a point on the roots, 1–2 cm from the hase of the stems, was almost independent of (a) the aeration conditions of the growth media; (b) the mechanical impedence to root growth offered by the media; (c) root length; (d) shoot length; (e) age of plant.

Summary Theory predicts that in the aqueous phase of aerobic soils carbon dioxide concentration/distance gradients are 1·35 times as large as those for oxygen. Because of differences in solubility, the partial pressure/distance gradients of carbon dioxide should be less than one-twentieth of the gradients of oxygen partial pressure. Experiments were carried out to test this prediction. In some experiments oxygen partial pressures were measured directly by means of a micro-electrode and carbon dioxide indirectly by methods involving microelectrode determinations of specific conductance in agar-CaCO3 gel. Measurements were made in models of water-saturated soil consisting of yeast cells embedded in agar-CaCO3 gel, around plant roots in agar-CaCO3 gel and within water-saturated soil. Oxygen partial pressures fell by 5–15 per cent of an atmosphere over distances of 0·2–0·4 cm whereas carbon dioxide partial pressures increased by less than 0·3 per cent of an atmosphere over the same distance. In other experiments different thicknesses of water-saturated soil were incubated with their upper surfaces exposed to air. The mean oxygen partial pressure fell by 7–13 per cent of an atmosphere with increasing the thickness from 0·2 to 0·4 cm whereas the carbon dioxide partial pressure never increased by more than 0·2 per cent of an atmosphere. Both sets of evidence confirm the theoretical prediction. It is concluded that the partial pressure of carbon dioxide in the aqueous phase of soils containing no oxygen-free zones, would never, even at the surfaces of roots, be more than 1 per cent of atmosphere greater than in the gas phase.

Summary Computer simulation techniques are presented as a means of applying diffusion theory to two problems concerning the dynamics of oxygen and carbon dioxide distributions in soils. It is demonstrated that these techniques facilitate both problem formulation and solution, and require less mathematical skill than the equivalent analytic techniques. For problems with no analytic solution, simulation can still yield results with an accuracy equal to other numerical methods. Using simulation techniques, it was computed that stationary state conditions for carbon dioxide in a 0·7 cm layer of soil were established 24 hours after waterlogging. Similarly it was computed that for oxygen diffusing through a 0·4 cm layer of soil, equilibrium was attained within six minutes. These data were useful in that they justified the assumptions regarding equilibrium conditions which had necessarily been made in previous experiments. Simulation techniques may be of widespread use, not only for solving diffusion problems, but also for applying other fundamental laws to specific situations.

Summary The micro electrode of Evans and Naylor was modified to permit measurements of oxygen concentration in soil and was used to determine the distribution of oxygen in (a) agar which contained yeast and glucose and served as a model of a respiring water-saturated soil; (b) saturated spherical soil aggregates; (c) partly saturated columns of fine soil crumbs. Measurements in (a) and (b) but not in (c) agreed closely with predictions by diffusion theory. The disagreement appeared to result from water being unevenly distributed in the columns.

Summary Evidence was obtained that oxygen transport through the plant greatly influenced the oxygen partial pressures in the medium surrounding the roots. Seedlings with their leaves in air had their roots embedded in agar gel that had been saturated with nitrogen, air or oxygen and after a 5-hour period of incubation the distribution of oxygen in the gel was determined. When the gel had been saturated with nitrogen gas, oxygen partial pressures increased towards the surfaces of the roots of whole plants but not towards the surfaces of severed roots. When the gel had been saturated with air or oxygen, however, oxygen partial pressures always decreased towards the root surfaces irrespective of whether the roots had been severed or not. In oxygenated gel, the decreases were much greater towards intact roots than towards those that had been severed but in aerated gel the converse held. The results were in agreement with those expected if substantial amounts of oxygen moved from stem to root or in the opposite direction depending on the sign and magnitude of the oxygen partial pressure/distance gradients.

Summary Experiments were carried out to determine whether oxygen could enter the leaves of vegetable seedlings and be transported through the tissues to the roots. The technique involved embedding seedlings in agar/potassium phosphate gel to exclude oxygen; the atmosphere around the leaves was varied and oxygen concentrations were measured at points on the root surface 0.5–2.0 cm from the junction of stem and root system. When the gas around the leaves was changed from nitrogen to oxygen, the oxygen concentration at the root surfaces increased rapidly. The rates of increase agreed approximately with those calculated by assuming that the plants contained continuous non-tortuous gas-filled channels, the view that diffusion through these channels was the means by which oxygen was transported through the plant, and that the gas channels were within about 12 μ of the root surfaces. Experiments were also carried out to determine whether the roots of seedlings could grow in oxygen-free media. Seedlings were grown in an atmosphere of air with their roots in columns of agar-gel containing yeast and glucose. Depending on the amount of yeast and glucose in the gel, the oxygen concentration fell to zero at depths of between 0.5 and 2.0 cm from the gel surface. Seedling roots rapidly penetrated oxygen-free zones in the gel but the extent of penetration appeared to be unrelated to the depth of zero oxygen concentration. A similar pattern of results was obtained with seedlings of twelve different species and it was concluded that the stems and roots of most seedlings contain continuous, non-tortuous gas channels through which oxygen diffused. When the plants were grown under anaerobic conditions such diffusion could satisfy all the roots’requirements for oxygen.