Maize resistance to witchweed through changes in strigolactone biosynthesis.

Maize (Zea mays) is a major staple crop in Africa, where its yield and the livelihood of millions are compromised by the parasitic witchweed Striga. Germination of Striga is induced by strigolactones exuded from maize roots into the rhizosphere. In a maize germplasm collection, we identified two strigolactones, zealactol and zealactonoic acid, which stimulate less Striga germination than the major maize strigolactone, zealactone. We then showed that a single cytochrome P450, ZmCYP706C37, catalyzes a series of oxidative steps in the maize-strigolactone biosynthetic pathway. Reduction in activity of this enzyme and two others involved in the pathway, ZmMAX1b and ZmCLAMT1, can change strigolactone composition and reduce Striga germination and infection. These results offer prospects for breeding Striga-resistant maize.

Synthesis of homopropargylamines from 2-cyanoazetidines.

2-Cyanoazetidines, easily accessible from ß-amino alcohols, undergo ring-cleavage upon reaction with trimethylsilylazide and catalytic amounts of Bu2SnO, to give the corresponding homopropargylamines which are isolated as their N-Boc protected derivatives. The scope of this reaction, which constitutes a new way to access these highly relevant building blocks, is examined in detail. The proposed mechanism involves a tin-catalyzed cycloaddition of the nitrile moiety with the azide to give the corresponding tetrazole, which decomposes with the extrusion of two molecules of dinitrogen to produce an intermediate vinylidene carbene that finally evolves to give the alkyne.

Aza-[2,3]-Wittig Sigmatropic Rearrangement of Allylic Tertiary Amines: A Successful Example with High Chirality Transfer.

We report herein a successful example of an aza-[2,3]-Wittig rearrangement in an allylic tertiary N,N-dibenzyl amine derived from (S)-alaninol or (S)-isoleucinol. This reaction occurs upon metalation at the benzylic position with a mixture of butyllithium/diisopropylamine/potassium t-butoxide and proceeds with a high 1,3 transfer of chirality.

[Temporal lift]. / Lifting temporal.

UNLABELLED: The temporal lift belongs to the traditional face lift which is in fact temporo-cervico-facial. It also forms part of the face lift "upper part of the face" which is in fact temporo-frontal. It is to say that it relates to a junction zone between the superior and inferior part of the face. OBJECTIVES: In a first part the authors recall the essential anatomical data including the eyebrow, the Charpy's fat pad, the galea and the temporoparietal fascia, the nerves (temporo-facial branch of the facial nerve and supra-orbital nerve) and the veins (sentinel vein). Then they expose the various surgical techniques (galeapexy, endoscopic temporal lift, brow lift, facial threads, standard fixing Endotine forehead, botulinic toxin. This makes it possible to define in a more precise way the indications and counterindications of the temporal lift. CONCLUSION: The indications of the temporal lift are the lateral ptosis of the tail of the brow. On the other hand, the total ptosis requires a frontal lift. In this case one can associate a concomitant blepharoplasty. The temporal lift is frequently carried out in a way combined with a cervico-cheek lift. The prospects for technical progress to improve perenniality of an isolated temporal gesture are large and will allow us to widen the indications.

[Humanitarian plastic surgery in question]. / La chirurgie plastique humanitaire en question.

Humanitarian plastic surgery has become very fashionable and more and more surgeons are attracted by this type of commitment. The authors remind here of the necessary conditions and limitations of these actions. The communicative action according to J. Habermas, which means a true partnership with the local health care specialists should be the only valid engagement.

Barium sulphate and soft-tissue radiology: allying the old and the new for the investigation of animal cutaneous microcirculation.

The study of microcirculation using angiography is essential to the advancement of flap and angiogenesis research in plastic surgery. Until the mid-1980s, barium sulphate was the most commonly used contrast material, although it did not provide optimal visualisation of the vascular tree. In 1986, a new technique using lead oxide was proposed, which permitted very high-quality imaging and rapidly became the technique of choice, despite its high toxicity. We reconsider the former technique of barium-sulphate injection and combine it with soft-tissue radiology using mammographic film to achieve a radiological definition similar to that obtained with lead oxide, and discuss the advantages and disadvantages of the two methods. We conclude that barium sulphate and the use of mammographic film is an accurate, simple and non-toxic method of analysing the cutaneous circulation in small animals.

Delivery of FGF-2 but not VEGF by encapsulated genetically engineered myoblasts improves survival and vascularization in a model of acute skin flap ischemia.

Stimulating angiogenesis by gene transfer approaches offers the hope of treating tissue ischemia which is untreatable by currently practiced techniques of vessel grafting and bypass surgery. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF-2) are potent angiogenic molecules, making them ideal candidates for novel gene transfer protocols designed to promote new blood vessel growth. In this study, an ex vivo gene therapy approach utilizing cell encapsulation was employed to deliver VEGF and FGF-2 in a continuous and localized manner. C(2)C(12) myoblasts were genetically engineered to secrete VEGF(121), VEGF(165) and FGF-2. These cell lines were encapsulated in hollow microporous polymer membranes for transplantation in vivo. Therapeutic efficacy was evaluated in a model of acute skin flap ischemia. Capsules were positioned under the distal, ischemic region of the flap. Control flaps showed 50% necrosis at 1 week. Capsules releasing either form of VEGF had no effect on flap survival, but induced a modest increase in distal vascular supply. Delivery of FGF-2 significantly improved flap survival, reducing necrosis to 34.2% (P < 0.001). Flap vascularization was significantly increased by FGF-2 (P < 0.01), with numerous vessels, many of which had a large lumen diameter, growing in the proximity of the implanted capsules. These results demonstrate that FGF-2, delivered from encapsulated cells, is more efficacious than either VEGF(121) or VEGF(165) in treating acute skin ischemia and improving skin flap survival. Furthermore, these data attest to the applicability of cell encapsulation for the delivery of angiogenic factors for the treatment and prevention of tissue ischemia.

Hypoxia-inducible angiopoietin-2 expression is mimicked by iodonium compounds and occurs in the rat brain and skin in response to systemic hypoxia and tissue ischemia.

Angiopoietins are ligands for the endothelial cell tyrosine kinase receptor Tie-2. Ang-1, the major physiological activator of Tie-2, promotes blood vessel maturation and stability. Ang-2 counteracts this effect by competitively inhibiting the binding of Ang-1 to Tie-2. Using a combined RNase protection/semiquantitative reverse transcriptase-polymerase chain reaction approach, we demonstrate that hypoxia up-regulates Ang-2 mRNA levels by up to 3.3-fold in two human endothelial cell lines. In bovine microvascular endothelial (BME) cells, the flavoprotein oxidoreductase inhibitor diphenylene iodonium (DPI) and the related compound iodonium diphenyl mimic induction of Ang-2 but not vascular endothelial growth factor (VEGF) by hypoxia; in combination with hypoxia, DPI further increases Ang-2 expression but has no effect on the induction of VEGF by hypoxia. Neither Ang-2 or VEGF was increased by cyanide or rotenone, suggesting that failure in mitochondrial electron transport is not involved in the oxygen-sensing system that controls their expression. In ischemic rat dorsal skin flaps or in the brain of rats maintained for 12 hours under conditions of hypoxia, Ang-2 mRNA was up-regulated 7.5- or 17.6- fold, respectively. VEGF was concomitantly increased, whereas expression of Ang-1, Tie-2, and the related receptor Tie-1 was unaltered. In situ hybridization localized Ang-2 mRNA to endothelial cells in hypoxic skin. These findings 1) show that up-regulation of Ang-2 by hypoxia occurs widely in endothelial cells in vitro and in vivo; 2) suggest that induction of Ang-2, but not VEGF, by hypoxia in BME cells is controlled by a flavoprotein oxidoreductase that is sensitive to iodonium compounds; and 3) point to Ang-2 and VEGF as independently regulated and selective effectors of hypoxia-induced vascular sprouting.

Surgical treatment of sacrococcygeal pilonidal sinus disease by excision and skin flaps: the Toulouse experience.

OBJECTIVE: To compare various techniques for the treatment of pilonidal sinus. DESIGN: Retrospective study SETTING: University Hospital of Toulouse, France. SUBJECTS: 246 consecutive patients who presented between 1979 and 1996. The male:female ratio was 2:1, and the mean age 26 years (range 18-69). INTERVENTIONS: 218 one or two stage excision and rotation skin flaps, and 28 simple incisions. RESULTS: 16 sinuses recurred, and no flaps necrosed. CONCLUSION: Excision and rotation skin flaps offers an effective and elegant alternative to the more classic operations for pilonidal sinus as it causes less postoperative pain and shortens convalescence.

["Saphenous vascular loop" technique in the treatment of lower limb defects. Report of five cases]. / Technique de la "boucle vasculaire saphène" dans le traitement des pertes de substance du membre inférieur. A propos de 5 cas.

Five patients with high energy trauma of the lower limb with tissue defect located in the knee or the proximal third of the leg underwent reconstruction with a free latissimus dorsi flap. This flap was connected to a vascular saphenous loop which initially creates an arterioveous shunt between proximal femoral vessels. This was performed in a single operation with two teams of surgeons. This technique was chosen because a healthy recipient pedicle was not available in the vicinity of the defect. Application of vein grafts is not the usual procedure but there are situations in which it becomes necessary. Our aim in this paper is to discuss these situations, to describe the technique used in our Hospital and to analyze the advantages and disadvantages of a one or two-stage operation.

Escalator injuries in Genevan children: a report of 6 cases.

We present a retrospective survey of the mechanism and the lesions caused by escalators in Genevan children. Though these accidents are rare, they are often very serious. They occur primarily among children around the age of three and affect especially the hand. It is not economically feasible to replace or modify current escalators. It is therefore important that the current warning signs on escalators be improved. As there is a specific risk to children of catching fingers in the escalator and most parents are unaware of this type of danger, a warning sign with an explicit illustration could be of value. Also an insertion of a plastic bar just above the moving stairs on each lateral wall would block any potential extremities from being caught in the gap between the steps and the side of the staircase.