BODIPY-Based Photothermal Agents with Excellent Phototoxic Indices for Cancer Treatment.

Here, we report six novel, easily accessible BODIPY-based agents for cancer treatment. In contrast to established photodynamic therapy (PDT) agents, these BODIPY-based compounds show additional photothermal activity and their cytotoxicity is not dependent on the generation of reactive oxygen species (ROS). The agents show high photocytotoxicity upon irradiation with light and low dark toxicity in different cancer cell lines in 2D culture as well as in 3D multicellular tumor spheroids (MCTSs). The ratio of dark to light toxicity (phototoxic index, PI) of these agents reaches striking values exceeding 830,000 after irradiation with energetically low doses of light at 630 nm. The oxygen-dependent mechanism of action (MOA) of established photosensitizers (PSs) hampers effective clinical deployment of these agents. Under hypoxic conditions (0.2% O2), which are known to limit the efficiency of conventional PSs in solid tumors, photocytotoxicity was induced at the same concentration levels, indicating an oxygen-independent photothermal MOA. With a PI exceeding 360,000 under hypoxic conditions, both PI values are the highest reported to date. We anticipate that small molecule agents with a photothermal MOA, such as the BODIPY-based compounds reported in this work, may overcome this barrier and provide a new avenue to cancer therapy.

Indigenous-Amazonian Traditional Medicine's Usage of the Tobacco Plant: A Transdisciplinary Ethnopsychological Mixed-Methods Case Study.

Harmful usage of tobacco is a global public health problem associated with adverse health effects and addiction. Yet, in the Peruvian Amazon, the native region of Nicotiana rustica L., this plant is used in remarkably different manners: it is considered a potent medicinal plant, applied in liquid form for oral ingestion to treat mental health problems, a common and ancient healing practice in this region. Using a transdisciplinary field research approach with mixed ethnopsychological methods, this work aimed to report for the first time a case study in this context. The intervention took place in the Peruvian Amazon (Loreto) and involved ritual tobacco ingestion in a weeklong retreat-like frame, administered by a specialized traditional Amazonian healer. The patient was a 37-year-old woman with diagnosed mood, anxiety, and attention deficit disorders, as well as a chronic somatic condition. We applied qualitative experience-sampling during and quantitative symptom assessments pre- and post-treatment. Our findings offer a detailed description of the experiential therapeutic process during the treatment week and suggest clinically relevant improvements in patient well-being. This work is significant in view of the globally prevalent harmful uses of tobacco and the current scientific trend of revisiting herbal psychoactives (e.g., cannabis, psilocybin) for their therapeutic potentials.

Development and In Vitro Assessment of a Novel Vacuum-Based Tissue-Holding Device for Laparoscopic and Robotic Kidney Cancer Operations.

In this paper, we describe the development and evaluation of a novel tissue-holding device (THD) for use during robotic-assisted laparoscopic partial nephrectomy. The THD is a vacuum-based apparatus made of either 3D-printed polyethylene or stainless steel. The proximal end connects to suction tubing routed outside the body, while the distal end is conically shaped and designed to firmly interface with the tumor. Device feasibility studies were performed on six porcine kidneys, two porcine livers, and two embalmed human cadavers. A Likert-scale rating was used to assess device setup, suction, and tissue handling. Additional tests were performed using the daVinci Xi® robotic system. Finally, the holding force of the THD was assessed using different standard vacuum systems and pressure settings. In porcine tissue, the device setup, tissue suction, and handling were rated as "good". THD insertion and removal was uncomplicated. In a simulated transabdominal approach on fixed human cadavers, the device setup, suction, and tissue handling were also rated as "good". No macroscopic tissue compromise or device deterioration was noted. The handling and holding abilities using the daVinci Xi® robotic system were also rated "good". The device was able to successfully hold over 300 g of tissue at a suction pressure of -600 mmHg. The preliminary evaluation of the THD demonstrated satisfactory results.

Teacher plants - Indigenous Peruvian-Amazonian dietary practices as a method for using psychoactives.

ETHNOPHARMACOLOGICAL RELEVANCE: Indigenous groups of the Amazon have developed intricate methods for the application of psychoactives, among which particularly the dieta or diet method of Peruvian-Amazonian traditional medicine stands out. It is a retreat-like intervention involving lengthy periods of social, behavioural, and alimentary restrictions, while ingesting specially prepared plant substances. The interplay of the dietary conditions and plants ingested sensitizes the dieter to receive healing, strength, guidance, and knowledge. From a clinical scientific point of view, the method has remained largely underexplored, but seems more pertinent than ever given the increasing interest in Amazonian psychoactive preparations including ayahuasca (Banisteriopsis caapi) and the burgeoning field of psychedelic-assisted therapies in general. AIM OF THE STUDY: This study offers a descriptive account and emic interpretation of the Peruvian-Amazonian dieta. More specifically we document in detail the procedure, its context and purpose of application, effects, modes of action, adverse effects, and risks, from the perspectives of a sample of Peruvian traditional healers. The Peruvian-Amazonian dieta is a multi-purpose method for making use of medicinal plants, many of which (but not all), are psychoactive; the current work especially focuses on its therapeutic applications in conjunction with psychoactives. METHODS: We interviewed 16 healers working in the Ucayali, San Martín, and Loreto provinces of Peru using a semi-structured interview approach. Interviews were audio-recorded and transcribed verbatim. The extensive data derived from these interviews were analysed by means of computer-assisted manifest qualitative content analysis using a theory-advancing approach. Over 500 coded text segments were categorized, resulting in 7 main theme clusters and corresponding sub-themes. RESULTS: The interviewed healers described a complex intervention with multifaceted applications (treatment, prevention, training) and effects in various domains (body, mind, spirit, energy). The process was portrayed as transformative, with benefits attributed to the effects of the so-called teacher plants in conjunction with the diet's conditions, along with the skill of the healer guiding the intervention. Further, a detailed risk assessment revealed sophisticated safety measures and tools designed to address adverse responses. The importance of adequate training of the healer that administers the diet was particularly highlighted in this context. CONCLUSIONS: The dieta is a central therapeutic concept and tool in Peruvian-Amazonian traditional medicine and a unique method for using psychoactive plants. Multidisciplinary health research that includes traditional treatment methods from Indigenous cultures, Amazonian and other, should not be neglected in the current global interest in psychedelic therapies; such research may in the long-term contribute to a more inclusive psychedelic research paradigm as well as healthcare practice in countries where rich traditional healing systems exist, and perhaps beyond. It may also contribute to the recognition of the Indigenous healers as not only historical forerunners, but also current leading experts in psychedelic medicine.

Treating Chronic Wounds Using Photoactive Metabolites: Data Mining the Chinese Pharmacopoeia for Potential Lead Species.

Efficient wound treatment that addresses associated infections and inflammation remains one of the big unmet needs, especially in low- and middle-income countries. One strategy for securing better healthcare can be using medicinal plants if sufficient evidence on their safety and therapeutic benefits can be ascertained. A unique novel opportunity could be photo-enhanced wound treatment with a combination of light-sensitive plant preparations and local exposure to daylight. Data mining strategies using existing resources offer an excellent basis for developing such an approach with many potential plant candidates. In the present analysis, we researched the 535 botanical drugs included in the Chinese pharmacopeia and identified 183 medicinal plant species, 82 for treating open wounds caused by trauma and 101 for inflammatory skin conditions. After further screening for reports on the presence of known photoactive compounds, we determined a core group of 10 scientifically lesser-known botanical species that may potentially be developed into more widely used topical preparations for photodynamic treatment of infected wounds. Our predictive approach may contribute to developing a more evidence-based use of herbal medicines.

Medicinal plants from the Himalayan region for potential novel antimicrobial and anti-inflammatory skin treatments.

BACKGROUND AND OBJECTIVES: Adequate treatment of wounds remains one of the major medical needs globally, most notably in the regions with poor or limited access to health care. In many local and traditional systems of medicine, plants are often widely used for treating infected wounds. AIM AND OBJECTIVES: The overarching aim of this project was selection of potential species for use in a future treatment by combining with plant resources with aspects of antimicrobial photodynamic therapy (aPDT). Specifically, we focussed on species used locally in the Himalayan region for the treatment of skin disorders and then assessed the existing pharmacological evidence for key species based on the published evidence available. METHODS: Database searches were performed to identify relevant publications describing local and traditional uses of plants in the Himalayan region of Bhutan, PR China, India, Nepal and Pakistan. Using the Global Biodiversity Information Facility (GBIF), species were researched in terms of their distribution including in different climatic regions, focussing on species mostly found in higher climatic zones (based on the Köppen-Geiger climate classification). For species used in three or more countries and restricted to the higher altitudes, data on safety, pharmacology, as it relates to dermatological conditions, and phytochemistry were retrieved. KEY FINDINGS: The study identified a total of 606 species that are used in the treatment of various skin conditions often associated with infections reported in 84 articles. Common weeds like Ageratum conyzoides and Bidens pilosa, widely used and cultivated species like Centealla asiatiaca and Prunus armenica were excluded. This ultimately led to the identification of a core group of five widely used species restricted to the Himalayan region (Cedrus deodara, Nardostachys jatamansi, Pinus wallichiana, Pinus roxburghii and Valeriana jatamansi). CONCLUSIONS: Here we apply a novel approach comprising an assessment of the published information on the use of medicinal plants (i.e. local and traditional knowledge) in the context of their potential to be used in a biomedical form of clinical treatment - aPDT. Then, once sustainable sourcing based on access and benefit-sharing arrangements is in place, these species are investigated for their potential in wound treatment. Ultimately, the goal is to develop a new baseline for primary health care in some of the regions of the world with poor or limited access to health care.

Cross-Reactivity and Functionality of Approved Human Immune Checkpoint Blockers in Dogs.

BACKGROUND: Rodent cancer models have limitations in predicting efficacy, tolerability and accompanying biomarkers of ICIs in humans. Companion dogs suffering from neoplastic diseases have gained attention as a highly relevant translational disease model. Despite successful reports of PD-1/PD-L1 blockade in dogs, no compounds are available for veterinary medicine. METHODS: Here, we assessed suitability of seven FDA-approved human ICIs to target CTLA-4 or PD-1/PD-L1 in dogs. Cross-reactivity and blocking potential was assessed using ELISA and flow cytometry. Functional responses were assessed on peripheral blood mononuclear cells (PBMCs) derived from healthy donors (n = 12) and cancer patient dogs (n = 27) as cytokine production after stimulation. Immune composition and target expression of healthy donors and cancer patients was assessed via flow cytometry. RESULTS: Four candidates showed cross-reactivity and two blocked the interaction of canine PD-1 and PD-L1. Of those, only atezolizumab significantly increased cytokine production of healthy and patient derived PBMCs in vitro. Especially lymphoma patient PBMCs responded with increased cytokine production. In other types of cancer, response to atezolizumab appeared to correlate with a lower frequency of CD8 T cells. CONCLUSIONS: Cross-functionality of atezolizumab encourages reverse translational efforts using (combination) immunotherapies in companion dog tumor patients to benefit both veterinary and human medicine.

Studying the cellular distribution of highly phototoxic platinated metalloporphyrins using isotope labelling.

Novel tetraplatinated metalloporphyrin-based photosensitizers (PSs) are reported, which show excellent phototoxic indexes (PIs) up to 5800 against HeLa cells, which is, to the best of our knowledge, the highest value reported for any porphyrin so far. Furthermore, 67Zn isotope labelling allowed the determination of the ratio of zinc to platinum inside the cells using ICP-MS.

"Tobacco Is the Chief Medicinal Plant in My Work": Therapeutic Uses of Tobacco in Peruvian Amazonian Medicine Exemplified by the Work of a Maestro Tabaquero.

INTRODUCTION: Harmful usage of tobacco is a public health problem of global concern and, in many countries, the main risk factor for non-communicable diseases. Yet, in the Peruvian Amazon, the geographical region believed to be tobacco's historical birthplace, this plant is associated with a strikingly different usage and repute: Tobacco (especially Nicotiana rustica L.) in this area is described as a potent medicinal plant, used topically or via ingestion to treat a variety of health conditions. The goal of this transdisciplinary field study was to investigate clinical applications of the tobacco plant as per Amazonian medicine exemplified in the practice of a reputed Maestro Tabaquero, an Amazonian traditional healer whose medical specialization focuses on tobacco-based treatments. METHODS: Using a transdisciplinary clinical approach, we conducted in-depth interviews with the tabaquero applying the systematizing expert interview method, in order to map modes of preparation and administration, indications, contraindications, effects, risks, adverse effects, and systemic aspects of tobacco-based remedies. RESULTS: The informant's descriptions revealed refined knowledge on this plant's therapeutic properties and scope, safety profile, and application techniques. The main indications mentioned included "problems of the mind," of the respiratory system, parasitic illnesses (intestinal/skin), gout, and Amazonian epistemic conditions described as spiritual-energetic in nature. A liquid remedy taken orally was his most commonly used preparation, with acute/sub-acute effects involving a pronounced psychoactive component (altered state of consciousness) and physiological response (emesis, nausea). A skilled tabaquero that knows how to dose, administer, and intervene in case of adverse effects was considered imperative for safe treatment delivery. CONCLUSIONS: To our knowledge, this is the first study employing a transdisciplinary clinical approach to examine therapeutic applications of tobacco by an Amazonian tabaquero. Our findings significantly contribute to the growing research literature on Amazonian medicine and emergent psychedelic-assisted therapies and could, in the long-term, open new treatment avenues in several domains. Forthcoming studies should assess toxicity/safety and clinical outcomes of patients receiving Amazonian tobacco-based treatment.

Access and Benefit Sharing Under the Nagoya Protocol-Quo Vadis? Six Latin American Case Studies Assessing Opportunities and Risk.

BACKGROUND: Global challenges related to access and benefit sharing (ABS) of biological resources have become a key concern in the area of research on herbal medicines, ethnopharmacology, drug discovery, and the development of other high value products for which Intellectual Property protection can be secured. While the Convention on Biological Diversity (CBD, Rio 1992) has been recognized as a huge step forward, the implementation of the Nagoya Protocol (NP) and of new forms of collaboration often remain unresolved, especially in the context of "the fair and equitable sharing of benefits arising from the utilization of genetic resources" (Convention on Biological Diversity, 2011). The vision and the specific implementation of this international treaty vary from country to country, which poses additional challenges. AIMS: Using a case study approach, in this analysis we aim at understanding the specific opportunities and challenges for implementing international collaborations regarding ABS in six Latin American countries-Chile, Colombia, Guatemala, México, Panama, and Peru. Based on that analysis, we provide recommendations for the path ahead regarding international collaborations under ABS agreements in ethnopharmacological research. RESULTS AND DISCUSSIONS: The implementation of the NP varies in the six countries; and while they are all rich in biodiversity, access and benefit sharing mechanisms differ considerably. There is a need to engage in a consultation process with stakeholders, but this has often come to a halt. Institutional infrastructures to implement national policies are weak, and the level of knowledge about the NP and the CBD within countries remains limited. CONCLUSIONS: Different policies in the six countries result in very diverse strategies and opportunities relating to the equitable use of biodiversity. A long-term strategy is required to facilitate a better understanding of the treaties and the resulting opportunities for a fairer development and implementation of transparent national polices, which currently differ in the six countries. So far, the benefits envisioned by the CBD and the NP remain unfulfilled for all stakeholders involved including local communities.

Silica-Coated TiN Particles for Killing Cancer Cells.

Photothermal therapy (PTT) using plasmonic nanoparticles for cancer treatment is on the verge of clinical application. Titanium nitride (TiN) nanoparticles offer a promising alternative to commonly used gold-based systems at a fraction of the costs. Little is known, however, about the relationship between TiN particle characteristics and their optical properties in colloidal systems. Here, TiN nanoparticles with closely controlled characteristics are prepared by nitridation of TiO2, and their use as PTT agents is explored. Emphasis is placed on the particle surface and core oxygen content, which dominate the TiN optical properties. Colloidal suspensions were studied under UV-vis and near-infrared (NIR) laser irradiation and correlated to particle characteristics. High nitridation temperatures and long residence times lead to increased NIR light absorption. Too high nitridation temperatures, however, lead to particle aggregation that deteriorated their optical properties. This was overcome with SiO2 coating of TiO2 nanoparticles prior to nitridation: the resulting SiO2-coated TiN particles exhibited increased plasmonic performance compared to bare TiN, which is attributed to reduced plasmonic coupling effects. The optimized SiO2-coated TiN had a photothermal efficiency of 58.5% and mass extinction coefficient of 31.6 L g-1 cm-1, outperforming commercial gold nanoshells that are used in clinical trials. The potential of SiO2-coated TiN for photothermal therapy was demonstrated by controllably killing HeLa cells in vitro.

Suspensory Ligaments of the Female Genital Organs: MRI Evaluation with Intraoperative Correlation.

The uterus, which plays an important role in the reproductive process, provides a home for the developing fetus and so must be in a stable, though flexible, location. Various structures with suspensory ligaments help provide this berth. MRI with high spatial resolution allows us to detect and evaluate these relatively fine structures. Under physiologic conditions, MRI can be used to depict uterine and ovarian ligaments (ie, the uterosacral, cardinal, and round ligaments, as well as the suspensory ligament of the ovary). In the presence of pathologic conditions (inflammation, endometriosis, tumors), the suspensory ligaments may appear thickened or invaded, which makes their delineation easier. Understanding the normal anatomy of the suspensory ligaments of the female genital organs and using a standardized nomenclature are essential for identifying and reporting related pathologic conditions. The female pelvic anatomy and the suspensory ligaments of the female genital organs are described as depicted with MRI. Also, the compartmental anatomy of the female pelvis is explained, including the extraperitoneal pelvic spaces. Finally, a checklist is provided for structured reporting of the MRI findings in the female pelvis. Online supplemental material is available for this article. ©RSNA, 2018.

Enhanced antitumor efficacy of biocompatible magnetosomes for the magnetic hyperthermia treatment of glioblastoma.

In this study, biologically synthesized iron oxide nanoparticles, called magnetosomes, are made fully biocompatible by removing potentially toxic organic bacterial residues such as endotoxins at magnetosome mineral core surfaces and by coating such surface with poly-L-lysine, leading to magnetosomes-poly-L-lysine (M-PLL). M-PLL antitumor efficacy is compared with that of chemically synthesized iron oxide nanoparticles (IONPs) currently used for magnetic hyperthermia. M-PLL and IONPs are tested for the treatment of glioblastoma, a dreadful cancer, in which intratumor nanoparticle administration is clinically relevant, using a mouse allograft model of murine glioma (GL-261 cell line). A magnetic hyperthermia treatment protocol is proposed, in which 25 µg in iron of nanoparticles per mm3 of tumor are administered and exposed to 11 to 15 magnetic sessions during which an alternating magnetic field of 198 kHz and 11 to 31 mT is applied for 30 minutes to attempt reaching temperatures of 43-46 °C. M-PLL are characterized by a larger specific absorption rate (SAR of 40 W/gFe compared to 26 W/gFe for IONPs as measured during the first magnetic session), a lower strength of the applied magnetic field required for reaching a target temperature of 43-46 °C (11 to 27 mT compared with 22 to 31 mT for IONPs), a lower number of mice re-administered (4 compared to 6 for IONPs), a longer residence time within tumours (5 days compared to 1 day for IONPs), and a less scattered distribution in the tumour. M-PLL lead to higher antitumor efficacy with full tumor disappearances achieved in 50% of mice compared to 20% for IONPs. This is ascribed to better ability of M-PLL, at equal iron concentrations, to maintain tumor temperatures at 43-46°C over a longer period of times.

Measuring tissue displacement of the anterior vaginal wall using the novel aspiration technique in vivo.

Little is known about the mechanical properties of pelvic floor structures and their role in the course and treatment of pelvic organ prolapse (POP). We hypothesize that in vivo mechanical properties of the vaginal wall are related to the appearance of POP and pre-and post-operative states. We used a suction device for intravaginal application, the aspiration device, to evaluate two in vivo mechanical parameters of the anterior vaginal wall, the load dependent tissue displacement and the initial displacement, by image analysis in pre- and post-menopausal women with (POP) and without (control) cystocele (POP: pre-menopausal: N = 6, post-menopausal: N = 19, control: pre-menopausal: N = 17, post-menopausal: N = 6). Mechanical parameters in women with and without cystocele and pre- and post-operative parameters were compared. Statistically significant differences were observed between the two mechanical parameters in pre- and post-operative states (P = 0.04, P = 0.03), but not between the parameters for women with and without cystocele (P = 0.92, P = 0.75). The mechanical behavior of pelvic floor structures is influenced by factors such as POP, age or estrogenization that are apparent at different length scales, which cannot be separated by the aspiration based biomechanical measurements. When comparing pre- and post-operative states of the same patient, a firmer tissue response was observed after intervention.

Lipid nanoemulsions and liposomes improve photodynamic treatment efficacy and tolerance in CAL-33 tumor bearing nude mice.

BACKGROUND: Photodynamic therapy (PDT) as promising alternative to conventional cancer treatments works by irradiation of a photosensitizer (PS) with light, which creates reactive oxygen species and singlet oxygen (1O2), that damage the tumor. However, a routine use is hindered by the PS's poor water solubility and extended cutaneous photosensitivity of patients after treatment. In our study we sought to overcome these limitations by encapsulation of the PS m-tetrahydroxyphenylchlorin (mTHPC) into a biocompatible nanoemulsion (Lipidots). RESULTS: In CAL-33 tumor bearing nude mice we compared the Lipidots to the existing liposomal mTHPC nanoformulation Foslip and the approved mTHPC formulation Foscan. We established biodistribution profiles via fluorescence measurements in vivo and high performance liquid chromatography (HPLC) analysis. All formulations accumulated in the tumors and we could determine the optimum treatment time point for each substance (8 h for mTHPC, 24 h for Foslip and 72 h for the Lipidots). We used two different light doses (10  and 20 J/cm2) and evaluated immediate PDT effects 48 h after treatment and long term effects 14 days later. We also analyzed tumors by histological analysis and performing reverse transcription real-time PCR with RNA extracts. Concerning tumor destruction Foslip was superior to Lipidots and Foscan while with regard to tolerance and side effects Lipidots were giving the best results. CONCLUSIONS: We could demonstrate in our study that nanoformulations are superior to the free PS mTHPC. The development of a potent nanoformulation is of major importance because the free PS is related to several issues such as poor bioavailability, solubility and increased photosensibility of patients. We could show in this study that Foslip is very potent in destroying the tumors itself. However, because the Lipidots' biocompatibility is outstanding and superior to the liposomes we plan to carry out further investigations and protocol optimization. Both nanoformulations show great potential to revolutionize PDT in the future.

Photoinduced effects of m-tetrahydroxyphenylchlorin loaded lipid nanoemulsions on multicellular tumor spheroids.

BACKGROUND: Photosensitizers are used in photodynamic therapy (PDT) to destruct tumor cells, however, their limited solubility and specificity hampers routine use, which may be overcome by encapsulation. Several promising novel nanoparticulate drug carriers including liposomes, polymeric nanoparticles, metallic nanoparticles and lipid nanocomposites have been developed. However, many of them contain components that would not meet safety standards of regulatory bodies and due to difficulties of the manufacturing processes, reproducibility and scale up procedures these drugs may eventually not reach the clinics. Recently, we have designed a novel lipid nanostructured carrier, namely Lipidots, consisting of nontoxic and FDA approved ingredients as promising vehicle for the approved photosensitizer m-tetrahydroxyphenylchlorin (mTHPC). RESULTS: In this study we tested Lipidots of two different sizes (50 and 120 nm) and assessed their photodynamic potential in 3-dimensional multicellular cancer spheroids. Microscopically, the intracellular accumulation kinetics of mTHPC were retarded after encapsulation. However, after activation mTHPC entrapped into 50 nm particles destroyed cancer spheroids as efficiently as the free drug. Cell death and gene expression studies provide evidence that encapsulation may lead to different cell killing modes in PDT. CONCLUSIONS: Since ATP viability assays showed that the carriers were nontoxic and that encapsulation reduced dark toxicity of mTHPC we conclude that our 50 nm photosensitizer carriers may be beneficial for clinical PDT applications.

Synthesis and screening of N-acyl thiolated chitosans for antibacterial applications.

Low-molecular weight chitosan-thioglycolic acid has shown significant antibacterial properties against different microorganisms. In order to explore the potential and structure-activity relationships of newly synthesized alkyl thiomers, chitosan has been functionalized with a series of thio-acids with increasing alkyl chain length. All thiomers were characterized with special emphasis on the determination of their degree of deacetylation and substitution, as well as on their molecular weight and amount of thiol groups. The pre-screened chitosan-thiomers were further investigated with plate counting on Pseudomonas aeruginosa, Streptococcus sobrinus and Streptococcus mutans. Furthermore, LIVE/DEAD assays supported the efficiency of chitosan-thiomers against the above microorganisms. All fully characterized chitosan-thiomers showed comparable or enhanced antimicrobial activity compared to pristine chitosan. Our comprehensive approach paves the way to detailed explorations of much sought-after structure activity relationships in the complex chitosan parameter room, starting from correlations between alkyl chain length and antimicrobial activity.

Hypericin-bearing magnetic iron oxide nanoparticles for selective drug delivery in photodynamic therapy.

Combining the concept of magnetic drug targeting and photodynamic therapy is a promising approach for the treatment of cancer. A high selectivity as well as significant fewer side effects can be achieved by this method, since the therapeutic treatment only takes place in the area where accumulation of the particles by an external electromagnet and radiation by a laser system overlap. In this article, a novel hypericin-bearing drug delivery system has been developed by synthesis of superparamagnetic iron oxide nanoparticles (SPIONs) with a hypericin-linked functionalized dextran coating. For that, sterically stabilized dextran-coated SPIONs were produced by coprecipitation and crosslinking with epichlorohydrin to enhance stability. Carboxymethylation of the dextran shell provided a functionalized platform for linking hypericin via glutaraldehyde. Particle sizes obtained by dynamic light scattering were in a range of 55-85 nm, whereas investigation of single magnetite or maghemite particle diameter was performed by transmission electron microscopy and X-ray diffraction and resulted in approximately 4.5-5.0 nm. Surface chemistry of those particles was evaluated by Fourier transform infrared spectroscopy and ζ potential measurements, indicating successful functionalization and dispersal stabilization due to a mixture of steric and electrostatic repulsion. Flow cytometry revealed no toxicity of pure nanoparticles as well as hypericin without exposure to light on Jurkat T-cells, whereas the combination of hypericin, alone or loaded on particles, with light-induced cell death in a concentration and exposure time-dependent manner due to the generation of reactive oxygen species. In conclusion, the combination of SPIONs' targeting abilities with hypericin's phototoxic properties represents a promising approach for merging magnetic drug targeting with photodynamic therapy for the treatment of cancer.

Deformation mechanisms of human amnion: Quantitative studies based on second harmonic generation microscopy.

Multiphoton microscopy has proven to be a versatile tool to analyze the three-dimensional microstructure of the fetal membrane and the mechanisms of deformation on the length scale of cells and the collagen network. In the present contribution, dedicated microscopic tools for in situ mechanical characterization of tissue under applied mechanical loads and the related methods for data interpretation are presented with emphasis on new stepwise monotonic uniaxial experiments. The resulting microscopic parameters are consistent with previous ones quantified for cyclic and relaxation tests, underlining the reliability of these techniques. The thickness reduction and the substantial alignment of collagen fiber bundles in the compact and fibroblast layer starting at very small loads are highlighted, which challenges the definition of a reference configuration in terms of a force threshold. The findings presented in this paper intend to inform the development of models towards a better understanding of fetal membrane deformation and failure, and thus of related problems in obstetrics and other clinical conditions.

Label-free, three-dimensional multiphoton microscopy of the connective tissue in the anterior vaginal wall.

INTRODUCTION AND HYPOTHESIS: Multiphoton microscopy (MPM) is a nonlinear, high-resolution laser scanning technique and a powerful approach for analyzing the spatial architecture within tissues. To demonstrate the potential of this technique for studying the extracellular matrix of the pelvic organs, we aimed to establish protocols for the detection of collagen and elastin in the vagina and to compare the MPM density of these fibers to fibers detected using standard histological methods. METHODS: Samples of the anterior vaginal wall were obtained from nine patients undergoing a hysterectomy or cystocele repair. Samples were shock frozen, fixed with formaldehyde or Thiel's solution, or left untreated. Samples were imaged with MPM to quantify the amount of collagen and elastin via second harmonic generation and autofluorescence, respectively. In six patients, sample sections were also histologically stained and imaged with brightfield microscopy. The density of the fibers was quantified using the StereoInvestigator and Cavalieri software. RESULTS: With MPM, collagen and elastin could be visualized to a depth of 100 µm, and no overlap of signals was detected. The different tissue processing protocols used did not result in significantly different fiber counts after MPM. MPM-based fiber quantifications are comparable to those based on conventional histological stains. However, MPM provided superior resolution, particularly of collagen fibers. CONCLUSIONS: MPM is a robust, rapid, and label-free method that can be used to quantify the collagen and elastin content in thick specimens of the vagina. It is an excellent tool for future three-dimensional studies of the extracellular matrix in patients with pelvic organ prolapse.