ALEXIS O-Ring wound retractor vs conventional wound protection for the prevention of surgical site infections in colorectal resections(1).

AIM: Surgical site infection (SSI) remains a common postoperative morbidity, particularly in colorectal resections, and poses a significant financial burden to the healthcare system. The omission of mechanical bowel preparation, as is performed in enhanced recovery after surgery programmes, appears to further increase the incidence. Various wound protection methods have been devised to reduce the incidence of SSIs. However, there are few randomized controlled trials assessing their efficacy. The aim of this study is to investigate whether ALEXIS wound retractors with reinforced O-rings are superior to conventional wound protection methods in preventing SSIs in colorectal resections. METHODOLOGY: Patients undergoing elective open colorectal resections via a standardized midline laparotomy were prospectively randomized to either ALEXIS or conventional wound protection in a double-blinded manner. A sample size of 30 in each arm was determined to detect a reduction of SSI from 20% to 1% with a power of 80%. Secondary outcomes included postoperative pain. The operative wound was inspected daily by a specialist wound nurse during admission, and again 30 days postoperatively. Statistical analysis was performed using spss version 13 with P < 0.05 considered significant. RESULTS: Seventy-two patients were recruited into the study but eight were excluded. There were no SSIs in the ALEXIS study arm (n = 34) but six superficial incisional SSIs (20%) were diagnosed in the control arm (P = 0.006). Postoperative pain score analysis did not demonstrate any difference between the two groups (P = 0.664). CONCLUSION: The ALEXIS wound retractor is more effective in preventing SSI in elective colorectal resections compared with conventional methods.

High sensitivity troponin T concentrations in patients undergoing noncardiac surgery: a prospective cohort study.

OBJECTIVES: To determine the proportion of noncardiac surgery patients exceeding the published 99th percentile or change criteria with the high sensitivity Troponin T (hs-TnT) assay. DESIGN AND METHODS: We measured hs-TnT preoperatively and postoperatively on days 1, 2 and 3 in 325 adults. RESULTS: Postoperatively 45% (95% CI: 39-50%) of patients had hs-TnT≥14ng/L and 22% (95% CI:17-26%) had an elevation (≥14ng/L) and change (>85%) in hs-TnT. CONCLUSION: Further research is needed to inform the optimal hs-TnT threshold and change in this setting.

A non-aphid-transmissible isolate of bean yellow mosaic potyvirus has an altered NAG motif in its coat protein.

An isolate of Bean yellow mosaic virus (BYMV) not transmitted by aphids (NAT) was compared with the aphid-transmissible isolate (MI) from which it was derived. For each isolate, the sequence of the coat protein and parts of the helper component was determined. A single nucleotide substitution caused a NAG to NAS alteration in the coat protein of the non aphid-transmissible isolate. Loss of aphid transmissibility in isolate BYMV(MI)-NAT was most likely caused by this mutation within the NAG motif. Systemic movement and accumulation of the virus in infected plants were not affected by the mutation.

Production of chrysanthemic acid and pyrethrins by tissue cultures ofChrysanthemum cinerariaefolium.

Tissue cultures ofChrysanthemum cinerariaefolium were established, and then used to study the production of pyrethrin insecticides, and their precursor chrysanthemic acid. Callus cultures and root-differentiated cultures did not contain pyrethrins whereas shoot differentiated callus was found to produce the pyrethrins. Chrysanthemic acid was isolated by extraction from callus cultures, and feeding(14)C-labelled chrysanthemic acid to a cell suspension ofC. cinerariaefolium established that the acid accumulates largely as a glucoside ester.

Regulation of Aspartate Kinase Isoenzymes in Barley Mutants Resistant to Lysine plus Threonine : Construction and Analysis of Combinations of the Lt1a, Lt1b, and Lt2 Mutant Genes.

Two homozygous mutant lines of barley (Hordeum vulgare L.) R3202 (Lt1b/Lt1b) and R3004 (Lt2/Lt2), are resistant to lysine plus threonine. They contain aspartate kinase isoenzymes with lost or decreased feedback sensitivity to lysine in either isoenzyme AKII (R3202) or isoenzyme AKIII (R3004). A homozygous double mutant line (Lt1b/Lt1b, Lt2/Lt2) has now been constructed that grows vigorously on 8 millimolar lysine, 8 millimolar threonine, and 1 millimolar arginine. Both AKII and AKIII from the double mutant have altered lysine sensitivities, identical to those previously observed in R3202 and R3004, respectively. Aspartate kinase activity in extracts of leaves, roots, and the maturing endosperm of the double mutant was much less sensitive to lysine inhibition than the enzyme in comparable extracts of the parent cv Bomi, suggesting that aspartate kinase is expressed in a similar manner in different tissues of barley.A further mutant, R2501, resistant to lysine plus threonine has now given rise to a homozygous line (Lt1a/Lt1a), which had previously not been possible. AKII isolated from the homozygous line was completely insensitive to 10 millimolar lysine; however, the combined action of 10 millimolar lysine and 0.8 millimolar S-adenosylmethionine inhibited it by 60%, demonstrating the retention of some of the regulatory characteristics of the wild type enzyme.

Lysine transport in two barley mutants with altered uptake of basic amino acids in the root.

Amino acid uptake was examined in two barley (Hordeum vulgare L.) mutants R906 and R4402 which had been selected as resistant to the lysine analog S-(2-aminoethyl)-cysteine. The mutants were found to be allelic by crossing and examination of F(1) and F(2) progeny. The mutant genes were designated aec1a and aec1b, respectively. The uptake of the basic amino acids lysine, arginine, and ornithine from 50 micromolar solutions was strongly decreased in roots of the mutants, whereas uptake of neutral and acidic amino acids was unaffected. The pattern of uptake of lysine over the range 10(-7) to 10(-2) molar was consistent with there being, principally, two uptake systems operating for basic amino acids in roots and that a low-concentration, high-affinity system is reduced or lacking in the mutants. The residual transport activity in the mutants had a different relative affinity for lysine and arginine to the wild-type system. Uptake of lysine by leaf slices was unimpaired in the mutants suggesting that the leaf uptake system is unaffected by the aec1 gene.

Proline accumulation in a barley mutant resistant to trans-4-hydroxy-L-proline.

Five proline analogues were tested for inhibition of the growth of mature barley (Hordeum vulgare L.) embryos in sterile culture. Inhibition by all analogues was relieved by proline. Inhibition by trans-4-hydroxy-L-proline was relieved by low amounts of proline. Twenty thousand mature embryos were dissected from M2 seeds after sodium azide mutagenesis. Four plants (Rothamsted 5201, 6102, 6901, 6902) were selected with good growth on 4 mM trans-4-hydroxyproline. Properties of mutant R5201 were studied in detail. Selfed progeny of R5201 were all resistant to trans-4-hydroxyproline and also to L-thiazolidine-4-carboxylic acid and trans-3-hydroxy-L-proline but not L-azetidine-2-carboxylic acid. The content of soluble proline in progeny of R5201 was higher in leaves by a factor of up to six-fold. Proline content was measured in the soluble fraction of the terminal 20 mm of 4 d old plants subjected to severe water stress in 40% w/v polyethylene glycol. Leaves of the mutant contained more proline initially and accumulated proline morer rapidly than the parental leaves. As mutant leaves were larger and lost water more rapidly the greater increase in proline may have been caused by more severe water stress. Resistance to trans-4-hydroxyproline in R5201 was due to a single partially dominant nuclear gene.