The flip-flap puzzle flap: Another recycling option

Post-traumatic soft tissue defects sometimes require sequential flap coverage to achieve complete healing. In the era of propeller flaps, which were developed to reduce donor site morbidity, Feng et al. introduced the concept of the free-style puzzle flap, in which a previously harvested flap becomes its own donor site by recycling the perforator. However, when a perforator cannot be found with a Doppler device, we suggest performing a new type of flap, the flip-flap puzzle flap, which combines two concepts: the free-style puzzle flap and the flip-flap flap described by Voche et al. in the 1990s. We present the cases of three patients who achieved complete healing through this procedure

Le cotyle de reconstruction saturne® dans les reprises acetabulaires de prothèses totales de hanche (résultats préliminaires sur 33 cas)

Les interventions de reprises d'arthroplastie totale de hanche sont en plein essor depuis la fin des années 1980. La révision du versant acétabulaire doit permettre d'obtenir une fixation stable dans le temps. Une reconstruction du stock osseux est souvent nécessaire dans les formes avec perte de substance importante, et permettra, le cas échéant. une reprise ultérieure dans de meilleures conditions. Cette étude rétrospective présentait les résultats cliniques et radiographiques de l'implant acétabulaire Saturne de reconstruction, ainsi que ses complications. Etaient anahsés tout particulièrement, les critères de stabilité de fixation, de reconstruction du stock osseux et de recentrage de la hanche. Trente trois cas de reprises pour échecs sévères d'arthroplastie totale de hanche étaient rapportés, au recul moyen de 33,6 mois. Les reprises septiques étaient exclues. La reconstruction s'associait à l'utilisation d'une autogreffe dans 18 cas (54,5%). Au recul final, les scores fonctionnels étaient significativement améliorés. Le score de Harris passait de 37.8 à 72,7 et le score PMA de 9,0 à 14,2. Trois cas de descellements itératifs étaient rapportés (9,1 ro) et 2 échecs d'ostéo intégration isolés (6,1 %). L'effet de recentrage et la reconstruction osseuse étaient significatifs. Aucune reprise itérative du versant acétabulaire et une seule (3.0%) du versant fémoral avait été réalisée au recul. L'analyse des complications retrouvaient un sepsis tardif profond (3.0%) et aucun épisode de luxation. Au total, l'implant Saturne® a permis de répondre aux exigences attendues dans la grande majorité des situations traitées. Ses limites semblaient cependant atteintes dans les situations de lésions osseuses étendues (stade lll de Paprosky). La double mobilité de sa cupule était efficace et aucune luxation n'avait été rapportée. La poursuite de l'analyse des résultats de cet implant est à poursuivre à plus long terme afin d'en fixer plus précisément les modalités d'utilisation.ROUEN-BU Médecine-Pharmacie (765402102) / SudocSudocFranceF

From Molecular Dynamics to Supramolecular Organization: The Role of PIM Lipids in the Originality of the Mycobacterial Plasma Membrane

Abstract Mycobacterium tuberculosis ( Mtb ) is the causative agent of tuberculosis, a disease that claims ~1.5 million lives annually. The current treatment regime is long and expensive, and missed doses contribute to drug resistance. There is much to be understood about the Mtb cell envelope, a complicated barrier that antibiotics need to negotiate to enter the cell. Within this envelope, the plasma membrane is the ultimate obstacle and is proposed to be comprised of over 50% mannosylated phosphatidylinositol lipids (phosphatidyl- myo inositol mannosides, PIMs), whose role in the membrane structure remains elusive. Here we used multiscale molecular dynamics (MD) simulations to understand the structure-function relationship of the PIM lipid family and decipher how they self-organize to drive biophysical properties of the Mycobacterial plasma membrane. To validate the model, we tested known anti-tubercular drugs and replicated previous experimental results. Our results shed new light into the organization of the Mycobacterial plasma membrane and provides a working model of this complex membrane to use for in silico studies. This opens the door for new methods to probe potential antibiotic targets and further understand membrane protein function. Abstract Figur

Supramolecular organisation and dynamics of mannosylated phosphatidylinositol lipids in the mycobacterial plasma membrane

Tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis (Mtb), a pathogen that claims ∼1.5 million lives annually. Drug susceptible infections are treated with a 6-month regime which is riddled with serious side-effects. Missed doses can contribute towards drug resistant and multi-drug resistant TB - an issue that is a global health concern. It is clear we need new methods to treat TB, but this pathogen is incredibly difficult to study experimentally and has physical barriers to prevent small molecule entry. The Mtb cell wall comprises of glycans and Mtb specific lipids that assemble into four discrete layers. The most well studied is the outer membrane which houses the mycolic acids but less is known about the inner layers - especially the plasma membrane. Bansal-Mutalik et al. (2014) proposed a unique composition, with over 50% of the lipids being mannosylated phosphatidylinositol lipids (phosphatidyl-myoinositol mannosides, PIMs). How PIMs contribute to the structure and function of the Mtb plasma membrane is yet to be fully elucidated. In this work we used multiscale molecular dynamics (MD) simulations to examine the structure-function relationship of the PIM lipids found in mycobacteria. The biophysical properties of the lipids in a bilayer were also investigated, looking at diffusion, rigidity, clustering, and density. The model was validated using membrane proteins and antibiotics known to interact with them, and experimental results were replicated in these simulations. Our results provide a robust workflow to assemble a mycobacterial membrane in silico to study how biophysical properties change as lipid composition changes, and hence how that might influence the passage of antibiotics into the cell

From Molecular Dynamics to Supramolecular Organization: The Role of PIM Lipids in the Originality of the <i>Mycobacterial</i> Plasma Membrane

AbstractMycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, a disease that claims ~1.5 million lives annually. The current treatment regime is long and expensive, and missed doses contribute to drug resistance. There is much to be understood about the Mtb cell envelope, a complicated barrier that antibiotics need to negotiate to enter the cell. Within this envelope, the plasma membrane is the ultimate obstacle and is proposed to be comprised of over 50% mannosylated phosphatidylinositol lipids (phosphatidyl-myoinositol mannosides, PIMs), whose role in the membrane structure remains elusive. Here we used multiscale molecular dynamics (MD) simulations to understand the structure-function relationship of the PIM lipid family and decipher how they self-organize to drive biophysical properties of the Mycobacterial plasma membrane. To validate the model, we tested known anti-tubercular drugs and replicated previous experimental results. Our results shed new light into the organization of the Mycobacterial plasma membrane and provides a working model of this complex membrane to use for in silico studies. This opens the door for new methods to probe potential antibiotic targets and further understand membrane protein function.Abstract Figure</jats:sec

Supramolecular organisation and dynamics of mannosylated phosphatidylinositol lipids in the mycobacterial plasma membrane

International audienceMycobacterium tuberculosis ( Mtb ) is the causative agent of tuberculosis (TB), a disease that claims ~1.6 million lives annually. The current treatment regime is long and expensive, and missed doses contribute to drug resistance. Therefore, development of new anti-TB drugs remains one of the highest public health priorities. Mtb has evolved a complex cell envelope that represents a formidable barrier to antibiotics. The Mtb cell envelop consists of four distinct layers enriched for Mtb specific lipids and glycans. Although the outer membrane, comprised of mycolic acid esters, has been extensively studied, less is known about the plasma membrane, which also plays a critical role in impacting antibiotic efficacy. The Mtb plasma membrane has a unique lipid composition, with mannosylated phosphatidylinositol lipids (phosphatidyl-myoinositol mannosides, PIMs) comprising more than 50% of the lipids. However, the role of PIMs in the structure and function of the membrane remains elusive. Here, we used multiscale molecular dynamics (MD) simulations to understand the structure-function relationship of the PIM lipid family and decipher how they self-organize to shape the biophysical properties of mycobacterial plasma membranes. We assess both symmetric and asymmetric assemblies of the Mtb plasma membrane and compare this with residue distributions of Mtb integral membrane protein structures. To further validate the model, we tested known anti-TB drugs and demonstrated that our models agree with experimental results. Thus, our work sheds new light on the organization of the mycobacterial plasma membrane. This paves the way for future studies on antibiotic development and understanding Mtb membrane protein function