Assessment of nerve involvement in the lumbar spine: agreement between magnetic resonance imaging, physical examination and pain drawing findings

<p>Abstract</p> <p>Background</p> <p>Detection of nerve involvement originating in the spine is a primary concern in the assessment of spine symptoms. Magnetic resonance imaging (MRI) has become the diagnostic method of choice for this detection. However, the agreement between MRI and other diagnostic methods for detecting nerve involvement has not been fully evaluated. The aim of this diagnostic study was to evaluate the agreement between nerve involvement visible in MRI and findings of nerve involvement detected in a structured physical examination and a simplified pain drawing.</p> <p>Methods</p> <p>Sixty-one consecutive patients referred for MRI of the lumbar spine were - without knowledge of MRI findings - assessed for nerve involvement with a simplified pain drawing and a structured physical examination. Agreement between findings was calculated as overall agreement, the p value for McNemar's exact test, specificity, sensitivity, and positive and negative predictive values.</p> <p>Results</p> <p>MRI-visible nerve involvement was significantly less common than, and showed weak agreement with, physical examination and pain drawing findings of nerve involvement in corresponding body segments. In spine segment L4-5, where most findings of nerve involvement were detected, the mean sensitivity of MRI-visible nerve involvement to a positive neurological test in the physical examination ranged from 16-37%. The mean specificity of MRI-visible nerve involvement in the same segment ranged from 61-77%. Positive and negative predictive values of MRI-visible nerve involvement in segment L4-5 ranged from 22-78% and 28-56% respectively.</p> <p>Conclusion</p> <p>In patients with long-standing nerve root symptoms referred for lumbar MRI, MRI-visible nerve involvement significantly underestimates the presence of nerve involvement detected by a physical examination and a pain drawing. A structured physical examination and a simplified pain drawing may reveal that many patients with "MRI-invisible" lumbar symptoms need treatment aimed at nerve involvement. Factors other than present MRI-visible nerve involvement may be responsible for findings of nerve involvement in the physical examination and the pain drawing.</p

A mathematical model of the link between growth and L-malic acid consumption for five strains of Oenococcus oeni

In winemaking, after the alcoholic fermentation of red wines and some white wines, L-malic acid must be converted into L-lactic acid to reduce the acidity. This malolactic fermentation (MLF) is usually carried out by the lactic acid bacteria Oenococcus oeni. Depending on the level of process control, selected O. oeni is inoculated or the natural microbiota of the cellar is used. This study considers the link between growth and MLF for five strains of O. oeni species. The kinetics of growth and L-malic acid consumption were followed in modified MRS medium (20 °C, pH 3.5, and 10 % ethanol) in anaerobic conditions. A large variability was found among the strains for both their growth and their consumption of L-malic acid. There was no direct link between biomass productivities and consumption of L-malic acid among strains but there was a link of proportionality between the specific growth of a strain and its specific consumption of L-malic acid. Experiments with and without malic acid clearly demonstrated that malic acid consumption improved the growth of strains. This link was quantified by a mathematical model comparing the intrinsic malic acid consumption capacity of the strains

Occurrence of hydrogen sulfide in wine and in fermentation: Influence of yeast strain and supplementation of yeast available nitrogen

Hydrogen sulfide (H2S) is a powerful aroma compound largely produced by yeast during fermentation. Its occurrence in wines and other fermented beverages has been associated with off-odors described as rotten egg and/or sewage. While the formation of hydrogen sulfide (H2S) during fermentation has been extensively studied, it is the final H2S content of wine that is actually linked to potential off-odors. Nevertheless, factors determining final H2S content of wine have received little attention, and it is commonly assumed that high H2S-forming fermentations will result in high final concentrations of H2S. However, a clear relationship has never been established. In this report, we investigated the contribution of yeast strain and nitrogen addition to H 2S formation during fermentation and its consequent occurrence the resulting wines. Five commercial Saccharomyces cerevisiae wine yeast strains were used to ferment a Chardonnay juice containing 110 mg/l of YAN (yeast assimilable nitrogen), supplemented with di-ammonium phosphate (DAP) to increase YAN concentration to moderate (260 mg/l) and high (410 mg/l) levels. In contrast to the widely reported decrease in H2S production in response to DAP addition, a non-linear relationship was found such that moderate DAP supplementation resulted in a remarkable increase in H2S formation by each of the five wine yeasts. H2S content of the finished wine was affected by yeast strain, YAN, and fermentation vigor. However, we did not observe a correlation between concentration of H 2S in the finished wines and H2S produced during fermentation, with low-forming fermentations often having relatively high final H2S and vice versa. Management of H2S in wine through nitrogen supplementation requires knowledge of initial YAN and yeast H 2S characteristics. \ua9 Society for Industrial Microbiology 2010

Rootstock and soil induce transcriptome modulation of phenylpropanoid pathway in grape leaves

Soil qualities and rootstocks are among the main factors that have been acknowledged to influence grape development as well as fruit and wine composition. Despite the role of soil and rootstock in establishing a successful vineyard in terms of grape quality, almost no molecular evidence linking soil and rootstock properties to the gene expression have been reported. The transcriptome variation in response to different soils and rootstocks was investigated through microarray technology. The cv. Pinot Noir was grown on different soils: sand, turf, and vineyard soil. The plants were grafted on the contrasting 101-14 and 1103 Paulsen rootstocks. The modulation of genes' expression in response to different soils and rootstocks was evaluated considering their potential impact on primary (carbohydrate) and secondary (phenylpropanoid) metabolisms. This study highlights a link among soil composition, rootstock, and gene expression. The results open a perspective for a molecular interpretation of the interaction between soil and grapevine