Thermosensitive liposomal drug delivery systems: state of the art review

Thermosensitive liposomes are a promising tool for external targeting of drugs to solid tumors when used in combination with local hyperthermia or high intensity focused ultrasound. In vivo results have demonstrated strong evidence that external targeting is superior over passive targeting achieved by highly stable long-circulating drug formulations like PEGylated liposomal doxorubicin. Up to March 2014, the Web of Science listed 371 original papers in this field, with 45 in 2013 alone. Several formulations have been developed since 1978, with lysolipid-containing, low temperature-sensitive liposomes currently under clinical investigation. This review summarizes the historical development and effects of particular phospholipids and surfactants on the biophysical properties and in vivo efficacy of thermosensitive liposome formulations. Further, treatment strategies for solid tumors are discussed. Here we focus on temperature-triggered intravascular and interstitial drug release. Drug delivery guided by magnetic resonance imaging further adds the possibility of performing online monitoring of a heating focus to calculate locally released drug concentrations and to externally control drug release by steering the heating volume and power. The combination of external targeting with thermosensitive liposomes and magnetic resonance-guided drug delivery will be the unique characteristic of this nanotechnology approach in medicine

Thermosensitive liposomal drug delivery systems: state of the art review

Thermosensitive liposomes are a promising tool for external targeting of drugs to solid tumors when used in combination with local hyperthermia or high intensity focused ultrasound. In vivo results have demonstrated strong evidence that external targeting is superior over passive targeting achieved by highly stable long-circulating drug formulations like PEGylated liposomal doxorubicin. Up to March 2014, the Web of Science listed 371 original papers in this field, with 45 in 2013 alone. Several formulations have been developed since 1978, with lysolipid-containing, low temperature-sensitive liposomes currently under clinical investigation. This review summarizes the historical development and effects of particular phospholipids and surfactants on the biophysical properties and in vivo efficacy of thermosensitive liposome formulations. Further, treatment strategies for solid tumors are discussed. Here we focus on temperature-triggered intravascular and interstitial drug release. Drug delivery guided by magnetic resonance imaging further adds the possibility of performing online monitoring of a heating focus to calculate locally released drug concentrations and to externally control drug release by steering the heating volume and power. The combination of external targeting with thermosensitive liposomes and magnetic resonance-guided drug delivery will be the unique characteristic of this nanotechnology approach in medicine

A Heat‐Activated Drug‐Delivery Platform Based on Phosphatidyl‐(oligo)‐glycerol Nanocarrier for Effective Cancer Treatment

The potential of cancer drugs is not fully exploited due to low tumor uptake and occurrence of systemic side effects, limiting maximum tolerated dose. Actively targeted nanocarriers improve efficacy while minimizing off‐target toxicity. Herein, it is the first time a drug‐delivery platform for heat‐triggered intravascular drug release is described, based on synthetic phosphatidyl‐(oligo)‐glycerols from organic synthesis to preclinical investigation in feline patients. For the nanocarrier formulated doxorubicin (DOX), superior tumor drug delivery and antitumor activity compared with free DOX, conventional liposomal DOX (Caelyx), and temperature‐sensitive lysolipid‐containing DOX‐liposomes in rat sarcoma are demonstrated. In a comparative oncological study with neoadjuvant treatment of feline sarcoma, a metabolic response determined with 18 F‐FDG‐positron emission tomography/magnetic resonance imaging (PET/MRI) and histopathological response after tumor resection are significantly better compared with free DOX, potentially by overcoming drug resistance based on improved intratumoral drug distribution. This novel drug‐delivery platform has great potential for the treatment of locally advanced tumors in humans

Antigenspecific immunsuppression in an animal model of myasthenia gravis

Mit Hilfe von Trifluormethansulfonsäure gelang die chemische Deglykosylierung von natürlichem Gelonin. Durch die Charakterisierung mit Hilfe von SDS-PAGE, wurden Hinweise auf das Vorliegen der Aminosäurensequenz von Nolan et al. gefunden. Durch Auswertung massenspektrometrischer Daten wurde ein mögliches Glykosylierungsmuster vorgeschlagen. Die Expression von rekombinantem Gelonin in E.coli und anschließende Isolierung mit Hilfe der Nickel-Affinitätschromatographie führte zu einem Produkt, das trotz fehlender Glykosylierung um den Faktor 2 toxischer war als natürliches Gelonin und vergleichbare immunologische Eigenschaften aufwies. Durch molekularbiologische Arbeiten wurde der Expressionsvektor für ein AChR-Fragment (a-Untereinheit, AS 4-181) um die DNA-Information für die Aminosäuren 182-208 erweitert. Eine Expression führte zur Bildung eines nativen Produktes, während die native Isolierung des verkürzten Fragmentes nicht erfolgreich war. Ein rekombinant hergestelltes Fusionsprotein aus Gelonin und einem AChR-Fragment (a-Untereinheit, AS 4-181) konnte in hoher Ausbeute und Reinheit mit Hilfe von Nickel-Affinitätschromatographie isoliert werden. Da eine denaturierende Aufarbeitung notwendig war, wurde eine geeignete Renaturierungsmethode entwickelt. Trotz Optimierung fielen allerdings noch bis zu 80% des Fusionsproteins als falsch-gefaltete, unlösliche Proteinaggregate aus. Durch Einführung einer „Recyclingmethode“ konnte der Proteinverlust deutlich minimiert werden. Beide Domänen zeigten sich nativ gefaltet. Allerdings war das Gelonin-Fragment um den Faktor 11 untoxischer als rekombinantes Gelonin alleine. Das Fusionsprotein wurde in einem Tiermodell der Myasthenia gravis auf seine potentiellen antigenspezifischen immunsuppressiven Eigenschaften gestestet. Nach der Induktion der Erkrankung in Ratten durch Gabe von komplettem AChR, wurde die Erkrankung durch repetitive Nervenstimulation untersucht. Eine Methode die auch bei humaner Myasthenie angewendet wird. Nach der Gabe des Fusionsproteins verschwanden die myasthenen Symptome in der Ratte innerhalb einer Woche. Damit zeigte das Fusionsprotein einen therapeutischen Effekt. Langzeitstudien wurden allerdings nicht durchgeführt.Trifluormethanesulfonic acid was used to deglycosylate the plant toxin gelonin, isolated from the seeds of Gelonium multiflorum. After characterization with SDS-PAGE hints for the amino acid sequence determined by Nolan et al. were found. After the evaluation of mass spectroscopic data from gelonin, a potential glycosylation pattern was calculated. The expression of recombinant gelonin in e.coli and the following isolation with affinity chromatography yielded pure protein. Recombinant gelonin was twice as toxic as natural gelonin, even without gylcosylation, and showed similar immunological properties. With the help of molecular biological techniques the extension of the expression vector for an acetylcholine receptor (AchR)-Fragment was achieved. It was possible to obtain the extracellular fragment of the alpha-subunit (aa 4-208) for the first time native in the cell lysate after expression in e.coli. A recombinant engineered fusion protein consisting of gelonin and an AChR-fragment (alpha-subunit, aa 4-181) was isolated in high yield an purity with the help of nickel-ion affinity chromatography. A denaturated isolation was necessary , so a refolding protocol was developed. To increase the yield of native fusion protein, a recycling method was used. Both domains of the protein were folded in native conformation, but the gelonin fragment was one magnitude less toxic, than recombinant gelonin alone. The fusion protein was tested in an animal model for myasthenia gravis for a possible antigenspecific immunsuppressive capability. After induction of the animal model in rats using complete AChR, the ongoing disease was examined with repetitive nerve stimulation. A method also used in the human disease. After the application of the fusion protein the myasthenic signs vanished during one week, showing the poitive effect of the protein in treatment of the disease. Long-term studies were not undertaken

Antigenspecific immunsuppression in an animal model of myasthenia gravis

Mit Hilfe von Trifluormethansulfonsäure gelang die chemische Deglykosylierung von natürlichem Gelonin. Durch die Charakterisierung mit Hilfe von SDS-PAGE, wurden Hinweise auf das Vorliegen der Aminosäurensequenz von Nolan et al. gefunden. Durch Auswertung massenspektrometrischer Daten wurde ein mögliches Glykosylierungsmuster vorgeschlagen. Die Expression von rekombinantem Gelonin in E.coli und anschließende Isolierung mit Hilfe der Nickel-Affinitätschromatographie führte zu einem Produkt, das trotz fehlender Glykosylierung um den Faktor 2 toxischer war als natürliches Gelonin und vergleichbare immunologische Eigenschaften aufwies. Durch molekularbiologische Arbeiten wurde der Expressionsvektor für ein AChR-Fragment (a-Untereinheit, AS 4-181) um die DNA-Information für die Aminosäuren 182-208 erweitert. Eine Expression führte zur Bildung eines nativen Produktes, während die native Isolierung des verkürzten Fragmentes nicht erfolgreich war. Ein rekombinant hergestelltes Fusionsprotein aus Gelonin und einem AChR-Fragment (a-Untereinheit, AS 4-181) konnte in hoher Ausbeute und Reinheit mit Hilfe von Nickel-Affinitätschromatographie isoliert werden. Da eine denaturierende Aufarbeitung notwendig war, wurde eine geeignete Renaturierungsmethode entwickelt. Trotz Optimierung fielen allerdings noch bis zu 80% des Fusionsproteins als falsch-gefaltete, unlösliche Proteinaggregate aus. Durch Einführung einer „Recyclingmethode“ konnte der Proteinverlust deutlich minimiert werden. Beide Domänen zeigten sich nativ gefaltet. Allerdings war das Gelonin-Fragment um den Faktor 11 untoxischer als rekombinantes Gelonin alleine. Das Fusionsprotein wurde in einem Tiermodell der Myasthenia gravis auf seine potentiellen antigenspezifischen immunsuppressiven Eigenschaften gestestet. Nach der Induktion der Erkrankung in Ratten durch Gabe von komplettem AChR, wurde die Erkrankung durch repetitive Nervenstimulation untersucht. Eine Methode die auch bei humaner Myasthenie angewendet wird. Nach der Gabe des Fusionsproteins verschwanden die myasthenen Symptome in der Ratte innerhalb einer Woche. Damit zeigte das Fusionsprotein einen therapeutischen Effekt. Langzeitstudien wurden allerdings nicht durchgeführt.Trifluormethanesulfonic acid was used to deglycosylate the plant toxin gelonin, isolated from the seeds of Gelonium multiflorum. After characterization with SDS-PAGE hints for the amino acid sequence determined by Nolan et al. were found. After the evaluation of mass spectroscopic data from gelonin, a potential glycosylation pattern was calculated. The expression of recombinant gelonin in e.coli and the following isolation with affinity chromatography yielded pure protein. Recombinant gelonin was twice as toxic as natural gelonin, even without gylcosylation, and showed similar immunological properties. With the help of molecular biological techniques the extension of the expression vector for an acetylcholine receptor (AchR)-Fragment was achieved. It was possible to obtain the extracellular fragment of the alpha-subunit (aa 4-208) for the first time native in the cell lysate after expression in e.coli. A recombinant engineered fusion protein consisting of gelonin and an AChR-fragment (alpha-subunit, aa 4-181) was isolated in high yield an purity with the help of nickel-ion affinity chromatography. A denaturated isolation was necessary , so a refolding protocol was developed. To increase the yield of native fusion protein, a recycling method was used. Both domains of the protein were folded in native conformation, but the gelonin fragment was one magnitude less toxic, than recombinant gelonin alone. The fusion protein was tested in an animal model for myasthenia gravis for a possible antigenspecific immunsuppressive capability. After induction of the animal model in rats using complete AChR, the ongoing disease was examined with repetitive nerve stimulation. A method also used in the human disease. After the application of the fusion protein the myasthenic signs vanished during one week, showing the poitive effect of the protein in treatment of the disease. Long-term studies were not undertaken

Study of nitrogen and carbon transfer from soil organic matter to Tuber melanosporum mycorrhizas and ascocarps using 15N and 13C soil labelling and wholegenome oligoarrays

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Mechanisms leading to tree species diversity effects: a test on water and light acquisition in mixed-forests

In the context of ecology studies on biodiversity and ecosystem functioning relationships, mixed-species forests have been highly studied over the past decade. Forests with a high diversity of treespecies are usually found to be more productive than monospecific ones (Toïgo et al. 2015). However,the aboveground and belowground mechanisms leading to these patterns are still not well understood(Forrester 2014). Furthermore, in the context of climate change, it is interesting to analyze whetherthese mechanisms can help mediate the effects of harsher climatic conditions such as drought(Grossiord et al. 2014). The objective of this study was to characterize the influence of tree species interactions on functionaltraits related to carbon and water acquisition of trees under various environmental conditions in mixedforests, in order to discuss the mechanisms leading to diversity effects. We measured tree-level water use efficiency using carbon isotope composition of the wood in treerings, leaf functional traits related to carbon and water acquisition and use, light availability for thedominant trees, and soil water acquisition. A triplet approach (3 different forest stands) was used tocompare these functional traits in pure and two-species stands. Measurements were conducted alonga latitudinal gradient in natural forests (5 sites in the South-East of France) in beech-silver fir or beech-pubescent oak forests. All data are available right now and statistical analyses are currently being processed. We expecttrees in mixed-stands to have enhanced access to water resources and thus display differentfunctional traits. Moreover, we hypothesize that aboveground interactions between species result inhigher light interception in mixed-stands. Finally, we expect that these effects should be stronger in thesites that are the most exposed to water stress

Mechanisms leading to tree species diversity effects: a test on water and light acquisition in mixed-forests

In the context of ecology studies on biodiversity and ecosystem functioning relationships, mixed-species forests have been highly studied over the past decade. Forests with a high diversity of treespecies are usually found to be more productive than monospecific ones (Toïgo et al. 2015). However,the aboveground and belowground mechanisms leading to these patterns are still not well understood(Forrester 2014). Furthermore, in the context of climate change, it is interesting to analyze whetherthese mechanisms can help mediate the effects of harsher climatic conditions such as drought(Grossiord et al. 2014). The objective of this study was to characterize the influence of tree species interactions on functionaltraits related to carbon and water acquisition of trees under various environmental conditions in mixedforests, in order to discuss the mechanisms leading to diversity effects. We measured tree-level water use efficiency using carbon isotope composition of the wood in treerings, leaf functional traits related to carbon and water acquisition and use, light availability for thedominant trees, and soil water acquisition. A triplet approach (3 different forest stands) was used tocompare these functional traits in pure and two-species stands. Measurements were conducted alonga latitudinal gradient in natural forests (5 sites in the South-East of France) in beech-silver fir or beech-pubescent oak forests. All data are available right now and statistical analyses are currently being processed. We expecttrees in mixed-stands to have enhanced access to water resources and thus display differentfunctional traits. Moreover, we hypothesize that aboveground interactions between species result inhigher light interception in mixed-stands. Finally, we expect that these effects should be stronger in thesites that are the most exposed to water stress

Nanomedicine-based strategies for treatment of atherosclerosis

Atherosclerosis is a chronic inflammatory disease of the arterial wall that arises from an imbalanced lipid metabolism and a maladaptive inflammatory response. Despite intensive research on mechanisms underlying atherosclerotic lesion formation and progression during the past decade, translation of this knowledge into the clinic is scarce. Although developments have primarily been made in the area of antitumor therapy, recent advances have shown the potential of nanomedicine-based treatment strategies for atherosclerosis. Here we describe the features of currently available nanomedical formulations that have been optimized for atherosclerosis treatment, and we further describe how they can be instructed to target inflammatory processes in the arterial wall. Despite their limitations, nanomedical applications might hold promise for personalized medicine, and further efforts are needed to improve atherosclerosis-specific targetin