Reviewing research priorities in weed ecology, evolution and management: a horizon scan.

Weedy plants pose a major threat to food security, biodiversity, ecosystem services and consequently to human health and wellbeing. However, many currently used weed management approaches are increasingly unsustainable. To address this knowledge and practice gap, in June 2014, 35 weed and invasion ecologists, weed scientists, evolutionary biologists and social scientists convened a workshop to explore current and future perspectives and approaches in weed ecology and management. A horizon scanning exercise ranked a list of 124 pre-submitted questions to identify a priority list of 30 questions. These questions are discussed under seven themed headings that represent areas for renewed and emerging focus for the disciplines of weed research and practice. The themed areas considered the need for transdisciplinarity, increased adoption of integrated weed management and agroecological approaches, better understanding of weed evolution, climate change, weed invasiveness and finally, disciplinary challenges for weed science. Almost all the challenges identified rested on the need for continued efforts to diversify and integrate agroecological, socio-economic and technological approaches in weed management. These challenges are not newly conceived, though their continued prominence as research priorities highlights an ongoing intransigence that must be addressed through a more system-oriented and transdisciplinary research agenda that seeks an embedded integration of public and private research approaches. This horizon scanning exercise thus set out the building blocks needed for future weed management research and practice; however, the challenge ahead is to identify effective ways in which sufficient research and implementation efforts can be directed towards these needs.

Efficacy and safety of oral alitretinoin (9-cis retinoic acid) in patients with severe chronic hand eczema refractory to topical corticosteroids: results of a randomized, double-blind, placebo-controlled, multicentre trial.

BACKGROUND: Patients with severe chronic hand eczema (CHE) refractory to topical corticosteroids currently have limited treatment options suited for chronic use, and few controlled clinical studies have investigated new therapies in this setting. OBJECTIVES: To assess the efficacy and safety of oral alitretinoin (9-cis retinoic acid) taken at 10 mg or 30 mg once daily for up to 24 weeks, compared with placebo control, in the treatment of severe CHE refractory to topical corticosteroids. METHODS: A randomized, double-blind, placebo-controlled, prospective, multicentre trial was conducted in 111 dermatology outpatient clinics in Europe and Canada. A total of 1032 patients with severe refractory CHE were randomized in a 1 : 2 : 2 ratio to placebo, or 10 mg or 30 mg of oral alitretinoin once daily for up to 24 weeks. Safety was assessed for all patients during a follow-up period of 4 weeks, and responders were observed for relapse for 24 weeks after the end of therapy. The primary efficacy parameter was Physician Global Assessment of overall CHE severity, with response defined as clear or almost clear hands. RESULTS: Responses, defined as clear or almost clear hands, were achieved in up to 48% of patients treated with alitretinoin, compared with 17% for placebo (P < 0.001), with up to 75% median reduction in disease signs and symptoms. Treatment was well tolerated, with dose-dependent adverse effects comprising headache, mucocutaneous events, hyperlipidaemia, and decreased free thyroxine and thyroid-stimulating hormone. The median time to relapse, defined as recurrence of 75% of initial signs and symptoms, was 5.5-6.2 months in the absence of anti-eczema medication. CONCLUSIONS: Alitretinoin given at well-tolerated doses induced clearing of CHE in a substantial proportion of patients with severe disease refractory to standard therapy.

A new method for histological microdissection utilizing an ultrasonically oscillating needle: demonstrated by differential mRNA expression in human lung carcinoma tissue.

Molecular analysis of microdissected tissue samples is used for analyzing tissue heterogeneity of histological specimens. We have developed a rapid one-step microdissection technique, which was applied for the selective procurement of tissue areas down to a minimum of 10 cell profiles. The special features of our microdissection system consist of an ultrasonically oscillating needle and a piezo-driven micropipette. The validity of this technique is demonstrated in human lung large-cell carcinoma by real-time quantitative reverse transcriptase-polymerase chain reaction assays of vimentin, cyclin D1, and carcinoembryonic antigen after linear RNA amplification. mRNA expression values of microdissected samples scattered around those of bulk tumor tissue and showed differential mRNA expression between samples of tumor parenchyma and supportive stromal cells for vimentin and carcinoembryonic antigen as confirmed by immunohistochemistry. In conclusion, this procedure requires simple equipment, is easily performed, and delivers microdissected tissue samples of oligocellular clusters suitable for further molecular analysis.

Survival and cardiovascular pathology of heterozygous Watanabe heritable hyperlipidaemic rabbits treated with pravastatin and probucol on a low-cholesterol (0.03%)-enriched diet.

This study was aimed at determining the effects of a combined pravastatin and probucol regimen on survival and vascular pathology of heterozygous Watanabe heritable hyperlipidaemic (WHHL) rabbits fed a low-cholesterol (0.03%)-enriched diet. Pravastatin monotherapy preceded the combined treatment. In animals receiving pravastatin and the enriched diet (verum group; n = 6), mean total serum cholesterol levels were consistently lowered at a dosage of 5 mg/kg pravastatin and with the combined treatment. Survival was increased (median 45 vs 25 months), while coronary atherosclerosis was less obstructive and altered to a more fibrous type than in controls (n = 8). The extent of aortic lesions, as determined by the relative plaque volume, was not related to survival in either group. However, aortic plaque types in verum group animals revealed less severe stages with a different composition and architecture, with a lower relative content of macrophage-derived foam cells and necrosis and a higher relative content of extracellular matrix. There was also a thicker fibrous cap than in control animals of similar age. Our data reveal a beneficial effect on survival of heterozygous WHHL rabbits when lipid-lowering and antioxidative treatment are combined. This appears to be due both to reduced coronary atherosclerosis and to a different, more stable type of atherosclerotic disease in this animal model.

Effects of pravastatin on cholesterol metabolism of cholesterol-fed heterozygous WHHL rabbits.

1. We administered the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor pravastatin at a daily dose of 1 mg kg(-1) body weight to cholesterol-fed (0.03%) heterozygous Watanabe heritable hyperlipidaemic rabbits, an animal model for heterozygous familial hypercholesterolaemia. 2. After 12 months of cholesterol treatment, immunohistochemistry with the monoclonal antibody 9D9 was used to detect hepatic low density lipoprotein (LDL) receptors, which were quantified by densitometry. In addition we determined LDL receptor mRNA by competitive reverse transcriptase polymerase chain reaction. The cholesterol precursor lathosterol and the plant sterol campesterol were analysed by gas-liquid chromatography. 3. The drug reduced total plasma cholesterol levels by 51% (P=0.04), when compared to the control group. Unexpectedly, hepatic LDL receptor density and mRNA showed no significant differences between the groups. Total plasma levels of lathosterol and campesterol also revealed no significant differences between the groups, if expressed relative to plasma cholesterol. 4. The findings suggest that mechanisms other than induced hepatic LDL receptors are responsible for the cholesterol-lowering effect of pravastatin in this animal model. We propose a reduced cholesterol absorption efficiency compatible with similar campesterol levels between both groups observed in our study.

Effects of low-dose pravastatin sodium on plasma cholesterol levels and aortic atherosclerosis of heterozygous WHHL rabbits fed a low cholesterol (0.03%) enriched diet for one year.

The aim of this study was to evaluate the cholesterol-lowering and antiatherosclerotic effect of the HMG-CoA reductase inhibitor pravastatin sodium at a dosage comparable to human therapy. Twelve heterozygous WHHL rabbits (13 months old) were fed 100 g per day of a low cholesterol (0.03%) enriched diet for 12 months. Six of these animals also received pravastatin sodium at a daily dose of 1 mg/kg body weight (verum group). In the verum group, total plasma cholesterol levels were lower by 47%(P < 0.05) and relative aortic plaque volume (% ratio of total plaque volume to the aortic lumen) was reduced by 78% (P < 0.05), when compared to the control group. Plaque composition was analysed at 30 cross-sectional levels of the entire aortic wall using a grid window. Compared to the control group, the plaque type, in terms of architecture and composition, was altered as follows: lesions in the verum group had no confluent atheromatous cores and showed a pattern of a diffuse mixture of the main plaque components with a decreased relative content of necrosis (-44%) and an increased relative content of smooth muscle cells (+19%), whereas the relative content of macrophage-derived foam cells and collagen were nearly unaffected. Furthermore, a similar plaque volume and type was observed in animals with comparable cholesterol profiles. There was no histologic evidence for structurally damaging effects of pravastatin sodium on the arterial wall. We conclude that pravastatin sodium reduces total plasma cholesterol levels in this animal model, thereby leading to smaller plaques and a different plaque type.

Termination of procollagen chain synthesis by puromycin. Evidence that assembly and secretion require a COOH-terminal extension.

Embryonic chick fibroblasts were incubated with [14C]proline and puromycin in the low concentrations of 1 to 3 mug/ml. The molecular weight of the synthesized procollagen chains, as measured by polyacrylamide gel electrophoresis in sodium dodecyl sulfate, was progressively reduced by increasing concentrations of puromycin in this range. For example, at 3 mug/ml the great majority of the [14C]proline was contained in procollagen chains having an average molecular weight of about 95,000 instead of the control value of 125,000. Associated with this decrease in molecular weight there was a marked decrease in the incorporation of cysteine although [14C]proline incorporation was relatively unaffedted. Disulfide bond formation was drastically inhibited as was triple helix formation as measured by resistance of the procollagen to pepsin digestion. Although the shortened procollagen chains were of normal hydroxyproline content, they nevertheless were secreted much more slowly than normal procollagen. Based upon these findings, we postulate that: (a) low concentrations of puromycin terminate procollagen chains before a COOH-terminal extension is completed, (b) these COOH-terminal extensions are required for normal assembly of the three individual procollagen chains and for triple helix formation, and (c) only assembled, triple helical procollagen molecules are selected for normal secretion.

Inhibition of the assembly and secretion of procollagen by incorporation of a threonine analogue, hydroxynorvaline.

Hydroxynorvaline (DL-alpha-amino-beta-hydroxyvaleric acid) was shown to competitively inhibit the activation of threonine and valine when tested with tRNA and synthetases prepared from whole chick embryos. However, the hydroxynorvaline was transferred only to threonyl-tRNA and not valyl-tRNA. The hydroxynorvaline had no effect when tested with other amino acids. The Km for threonine was 25 muM and the Ki for hydroxynorvaline was 181 muM. When fibroblasts from embryonic chick tendons were incubated with [3H]threonine and increasing concentrations of hydroxynorvaline, there was a progressive decrease in the incorporation of [3H]threonine so that 1 mM hydroxynorvaline the incorporation into nondialyzable protein was 26% of the control value. A much smaller decrease in the incorporation of other radioactive amino acids was observed. When the cells were incubated hith [14C]proline and 1 mM hydroxynorvaline, the labeled procollagen containing hydroxynorvaline accumulated intracellularly and very little was secreted. Control experiments demonstrated that free hydroxynorvaline did not inhibit the secretion of unsubstituted procollagen. Although the individual pro alpha chains containing hydroxynorvaline were of normal molecular weight (125,000) and hydroxyproline content, only about 50% of this intracellularly retained procollagen was triple helical within the cell as 37 degrees as measured by sensitivity to pepsin digestion. Also only approximately 50% of the pro alpha chains were disulfide-linked to form triple stranded molecules as compared to greater than 85% linkage in unsubstituted procollagen. We postulate that incorporation of hydroxynorvaline alters the conformation of the propeptide extension sufficiently so that: (a) normal assembly of disulfide-linked, triple helical molecules is reduced and (b) assembled triple helical molecules are not properly recognized by the secretory mechanism.