scholarly journals Drosophila Dendritic Arborisation Neurons: Fantastic Actin Dynamics and Where to Find Them

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2777
Author(s):  
Lukas Kilo ◽  
Tomke Stürner ◽  
Gaia Tavosanis ◽  
Anna B. Ziegler
Keyword(s):  
Time Course ◽  
Dendritic Tree ◽  
Morphological Diversity ◽  
Structural Diversity ◽  
Actin Dynamics ◽  
In Vivo Studies ◽  
Functional Requirements ◽  
Neuronal Dendrites ◽  
Dendrite Development

Neuronal dendrites receive, integrate, and process numerous inputs and therefore serve as the neuron’s “antennae”. Dendrites display extreme morphological diversity across different neuronal classes to match the neuron’s specific functional requirements. Understanding how this structural diversity is specified is therefore important for shedding light on information processing in the healthy and diseased nervous system. Popular models for in vivo studies of dendrite differentiation are the four classes of dendritic arborization (c1da–c4da) neurons of Drosophila larvae with their class-specific dendritic morphologies. Using da neurons, a combination of live-cell imaging and computational approaches have delivered information on the distinct phases and the time course of dendrite development from embryonic stages to the fully developed dendritic tree. With these data, we can start approaching the basic logic behind differential dendrite development. A major role in the definition of neuron-type specific morphologies is played by dynamic actin-rich processes and the regulation of their properties. This review presents the differences in the growth programs leading to morphologically different dendritic trees, with a focus on the key role of actin modulatory proteins. In addition, we summarize requirements and technological progress towards the visualization and manipulation of such actin regulators in vivo.

scholarly journals Pharmacokinetic–pharmacodynamic guided optimisation of dose and schedule of CGM097, an HDM2 inhibitor, in preclinical and clinical studies

2021 ◽  
Author(s):  
Sebastian Bauer ◽  
George D. Demetri ◽  
Ensar Halilovic ◽  
Reinhard Dummer ◽  
Christophe Meille ◽  
...  
Keyword(s):  
Partial Response ◽  
Disease Control ◽  
Time Course ◽  
Oral Treatment ◽  
Preliminary Evidence ◽  
Disease Control Rate ◽  
In Vivo Studies ◽  
Hematologic Toxicity ◽  
Next Generation

Abstract Background CGM097 inhibits the p53-HDM2 interaction leading to downstream p53 activation. Preclinical in vivo studies support clinical exploration while providing preliminary evidence for dosing regimens. This first-in-human phase I study aimed at assessing the safety, MTD, PK/PD and preliminary antitumor activity of CGM097 in advanced solid tumour patients (NCT01760525). Methods Fifty-one patients received oral treatment with CGM097 10–400 mg 3qw (n = 31) or 300–700 mg 3qw 2 weeks on/1 week off (n = 20). Choice of dose regimen was guided by PD biomarkers, and quantitative models describing the effect of CGM097 on circulating platelet and PD kinetics. Results No dose-limiting toxicities were reported in any regimens. The most common treatment-related grade 3/4 AEs were haematologic events. PK/PD models well described the time course of platelet and serum GDF-15 changes, providing a tool to predict response to CGM097 for dose-limiting thrombocytopenia and GDF-15 biomarker. The disease control rate was 39%, including one partial response and 19 patients in stable disease. Twenty patients had a cumulative treatment duration of >16 weeks, with eight patients on treatment for >32 weeks. The MTD was not determined. Conclusions Despite delayed-onset thrombocytopenia frequently observed, the tolerability of CGM097 appears manageable. This study provided insights on dosing optimisation for next-generation HDM2 inhibitors. Translational relevance Haematologic toxicity with delayed thrombocytopenia is a well-known on-target effect of HDM2 inhibitors. Here we have developed a PK/PD guided approach to optimise the dose and schedule of CGM097, a novel HDM2 inhibitor, using exposure, platelets and GDF-15, a known p53 downstream target to predict patients at higher risk to develop thrombocytopenia. While CGM097 had shown limited activity, with disease control rate of 39% and only one patient in partial response, the preliminary data from the first-in-human escalation study together with the PK/PD modeling provide important insights on how to optimize dosing of next generation HDM2 inhibitors to mitigate hematologic toxicity.

Trajectory-Based Tissue Engineering for Cartilage Repair: Correlation Between Maturation Rate and Integration Capacity

2013 ◽  
Author(s):  
Matthew B. Fisher ◽  
Nicole Söegaard ◽  
David R. Steinberg ◽  
Robert L. Mauck
Keyword(s):  
Tissue Engineering ◽  
Time Course ◽  
Biomechanical Properties ◽  
Time Dependent ◽  
In Vivo Studies ◽  
Surgical Approaches ◽  
General Hypothesis ◽  
Vitro Assay

Given the limitations of current surgical approaches to treat articular cartilage injuries, tissue engineering (TE) approaches have been aggressively pursued over the past two decades. Although biochemical and biomechanical properties on the order of the native tissue have been achieved (1–5), several in-vitro and in-vivo studies indicate that increased tissue maturity may limit the ability of engineered constructs to remodel and integrate with surrounding cartilage, although results are highly variable (2, 6–8). Thus, “static” measures of construct maturity (e.g. compressive modulus) upon implantation may not be the best indicators of in-vivo success, which likely requires implanted TE constructs to mature, remodel, and integrate with the host over time to achieve optimal results. We recently introduced the concept of “trajectory-based” tissue engineering (TB-TE), which is based on the general hypothesis that time-dependent increases in construct maturation in-vitro prior to implantation (i.e. positive rates) may provide a better predictor of in-vivo success (9). As a first step in evaluating this concept, in the current study we hypothesized that time-dependent increases in equilibrium modulus (a metric of growth) would be correlated to ability of constructs to integrate to cartilage using an in-vitro assay. To test this hypothesis, the current objective was to determine and model the time course of maturation of TE constructs during in-vitro culture and to assess the ability of these constructs to integrate to cartilage at various points during their maturation.

Systemic telomerase gene therapy delivered via targeted lipidic nanoparticles

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 13025-13025 ◽  
Author(s):  
A. Goldkorn ◽  
B. Hann ◽  
M. Hayes ◽  
D. C. Drummond ◽  
D. B. Kirpotin ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Time Course ◽  
Cancer Metastasis ◽  
Tumor Formation ◽  
In Vivo Studies ◽  
Control Group ◽  
Telomerase Rna ◽  
Single Chain ◽  
Dna Nanoparticles

13025 Background: Most human cancers possess elevated telomerase activity that promotes proliferation. We developed 2 telomerase-targeting gene constructs: telomerase RNA containing a mutated template sequence (MT-hTer), and short interfering RNA (siRNA) targeting endogenous wild type telomerase RNA. When co-expressed in cancer cell lines and xenografts, MT-hTer/siRNA synergizes to cause rapid cell death (Li, S et al. Cancer Research 2004). Here, we tested the in vivo efficacy of MT-hTer/siRNA delivered systemically via antibody-targeted lipidic nanoparticles in a breast cancer metastasis model. Methods: Nude mice received intracardiac injection of luc+MCF7-C18 breast carcinoma cells ectopically overexpressing HER2 and luciferase. After 3 days, the mice were treated with a single 100 μg i.v. injection of either MT-hTer/siRNA-GFP or control (GFP-only) plasmid formulated into lipid-DNA nanoparticles conjugated to an internalizing anti-HER2 single chain antibody (Genosphere, TM) (Hayes, M et al. Gene Therapy 2005). A third group received saline (PBS) as a vehicle control. Cancer progression was monitored non-invasively via biophotonic imaging (Xenogen) of tumor luciferase signal. Results: By week 2 the PBS control group showed luciferase signal elevation that increased exponentially during the study. Similarly, the GFP-only control group developed significant luciferase signal elevation by week 3, with continued rise at all subsequent time points. In contrast, the MT-hTer/siRNA-GFP group experienced a decreased luciferase signal by week 2, which remained consistently low throughout the experimental time course. There were no observed treatment-related toxicities. Conclusions: In pilot in vivo studies, telomerase therapy dramatically inhibited tumor formation in mice after systemic delivery with cancer-targeting lipid-DNA nanoparticles. Expanded preclinical studies are underway. [Table: see text]

The Fibrinolytic Potential of the Normal Primate following the Generation of Thrombin In Vivo

1990 ◽  
Vol 63 (03) ◽  
pp. 476-481 ◽  
Author(s):  
Alan R Giles ◽  
Michael E Nesheim ◽  
Steven W Herring ◽  
Hugh Hoogendoorn ◽  
David C Stump ◽  
...  
Keyword(s):  
Time Course ◽  
Factor Xa ◽  
Lipid Vesicles ◽  
Experimental Period ◽  
In Vivo Studies ◽  
Full Time ◽  
Primate Model ◽  
Fibrinolytic Potential

SummaryParameters of the fibrinolytic system were studied in a primate model where the generation of thrombin was promoted in vivo. The procoagulant stimulus used was a combination of human factor Xa in combination with phosphatidylcholine/phos-phatidylserine lipid vesicles (PCPS) as the source of coagulant active phospholipid. The dosage of each component was formulated to provide a gradation of thrombin generating potential assessed prior to in vivo study in an in vitro clotting assay. These ranged from 25.25 - 36.60 pMole/kg (factor Xa) and 18.85 - 56.30 nMole/kg (PCPS). In each case, the ratio of the dose of factor Xa/PCPS was maintained at 0.65 (pMole factor Xa/ nMole PCPS). Individual dosage combinations producing recalcification clotting times in vitro of 15, 20, 25 and 30 s were used in detailed in vivo studies. Previous studies in dogs had confirmed the thrombin generating potential of factor Xa/PCPS infusions and demonstrated an associated activation ot protein C and increased fibrinolytic activity. This has now been extensively characterized in the chimpanzee as follows: 10 min after the infusion of the highest dose (36.6 pMole factor Xa/56.3 nMole PCPS kg bodyweight), the level of circulating t-PA had risen to 900 ng/ml (antigen), 885 IU/ml (functional). Dosage was observed with the lowest dose of 12.25 pMole factor Xa and 18.85 nMole PCPS being associated with relatively minor increases in circulating t-PA activity. There were no changes in u-PA at any dosage during the full time course of the experimental period (90 min). Plasminogen activation was also apparent with alpha-2 antiplasmin levels falling to 30 - 40% of pre-infusion levels at the highest dosages. There was also a significant consumption of fibrinogen and evidence of active fibrinolysis manifested by major increases in the levels of FDP, D-dimer and B-beta 1-42. The data strongly suggested that this was predominantly fibrinolysis rather than fibrinogenolysis and that the fibrinolytic response observed resulted from a major release of t-PA from available stores consequent to thrombin generation and presumably subsequent fibrin generation. These data illustrate the enormous fibrinolytic potential of the intact normal primate and may provide a model for study of the mechanism(s) by which the regulation of t-PA availability can be up- or down-regulated in health and disease.

Role of lipid peroxidation in H2O2-induced renal epithelial (LLC-PK1) cell injury

1995 ◽  
Vol 268 (1) ◽  
pp. F30-F38 ◽  
Author(s):  
A. K. Salahudeen
Keyword(s):  
Lipid Peroxidation ◽  
Renal Cell ◽  
Time Course ◽  
Cell Injury ◽  
Thiobarbituric Acid ◽  
Alpha Tocopherol ◽  
In Vivo Studies ◽  
Sequence Of Events

The exact sequence of events or mechanisms by which H2O2 induces renal cell injury remains undetermined. Specifically, whether the attendant lipid peroxidation is a cause or an effect remains unclear. Employing H2O2 and LLC-PK1 cells, we tested the hypothesis that lipid peroxidation is a seminal event and that its inhibition is cytoprotective. In a time course study, lipid peroxidation (thiobarbituric acid reaction) and degradation (release of [3H]arachidonic acid) preceded H2O2-induced cytolysis (51Cr and lactate dehydrogenase release). The role of preceding lipid peroxidation in cytolysis was examined with lipid radical scavengers. alpha-Tocopherol and lazaroid compound 2-methyl aminochroman dose-dependently inhibited H2O2-induced lipid peroxidation and prevented cytolysis. 2-Methyl aminochroman cytoprotection was associated with blockade of lipid degradation. 21-Aminosteroid, another lazaroid, also inhibited lipid peroxidation and prevented cytolysis. These findings provide evidence that lipid alterations contribute to H2O2-mediated LLC-PK1 injury and, for the first time, demonstrate the potency of lazaroids in a renal cell line. In vivo studies with lazaroids may define the role of lipid peroxidation in acute renal injury models.

scholarly journals Silver Nanoparticles-Composing Alginate/Gelatine Hydrogel Improves Wound Healing In Vivo

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 390 ◽  
Author(s):  
Flavia Resende Diniz ◽  
Romerito Cesar A. P. Maia ◽  
Lucas Rannier Andrade ◽  
Luciana Nalone Andrade ◽  
Marco Vinicius Chaud ◽  
...  
Keyword(s):  
Wound Healing ◽  
Silver Nanoparticles ◽  
Sodium Alginate ◽  
Time Course ◽  
In Vivo Studies ◽  
Natural Polymers ◽  
Cutaneous Lesions ◽  
Cutaneous Wounds ◽  
Healing Tissue

Polymer hydrogels have been suggested as dressing materials for the treatment of cutaneous wounds and tissue revitalization. In this work, we report the development of a hydrogel composed of natural polymers (sodium alginate and gelatin) and silver nanoparticles (AgNPs) with recognized antimicrobial activity for healing cutaneous lesions. For the development of the hydrogel, different ratios of sodium alginate and gelatin have been tested, while different concentrations of AgNO3 precursor (1.0, 2.0, and 4.0 mM) were assayed for the production of AgNPs. The obtained AgNPs exhibited a characteristic peak between 430–450 nm in the ultraviolet-visible (UV–Vis) spectrum suggesting a spheroidal form, which was confirmed by Transmission Electron Microscopy (TEM). Fourier Transform Infra-red (FT–IR) analysis suggested the formation of strong intermolecular interactions as hydrogen bonds and electrostatic attractions between polymers, showing bands at 2920, 2852, 1500, and 1640 cm−1. Significant bactericidal activity was observed for the hydrogel, with a Minimum Inhibitory Concentration (MIC) of 0.50 µg/mL against Pseudomonas aeruginosa and 53.0 µg/mL against Staphylococcus aureus. AgNPs were shown to be non-cytotoxic against fibroblast cells. The in vivo studies in female Wister rats confirmed the capacity of the AgNP-loaded hydrogels to reduce the wound size compared to uncoated injuries promoting histological changes in the healing tissue over the time course of wound healing, as in earlier development and maturation of granulation tissue. The developed hydrogel with AgNPs has healing potential for clinical applications.

scholarly journals In Vivo Pharmacodynamic Characterization of Anidulafungin in a Neutropenic Murine Candidiasis Model

2007 ◽  
Vol 52 (2) ◽  
pp. 539-550 ◽  
Author(s):  
D. Andes ◽  
D. J. Diekema ◽  
M. A. Pfaller ◽  
R. A. Prince ◽  
K. Marchillo ◽  
...  
Keyword(s):  
Drug Concentration ◽  
Time Course ◽  
Dose Range ◽  
Treatment Success ◽  
In Vivo Studies ◽  
Serum Drug Concentration ◽  
Time Curve ◽  
Maximum Serum ◽  
Dosing Regimens

ABSTRACT Multiple in vivo studies have characterized the pharmacodynamics of drugs from the triazole and polyene antifungal drug classes. Fewer studies have investigated these pharmacodynamic relationships for the echinocandin drug class. We used a neutropenic murine model of disseminated Candida albicans, Candida tropicalis, and Candida glabrata infection to characterize the time course of activity of the new echinocandin anidulafungin. The pharmacokinetic-pharmacodynamic (PK-PD) indices (the percentage of time that the drug concentration was above the MIC, the ratio of the area under the concentration-time curve from 0 to 24 h [AUC0-24] to the MIC, and the ratio of the maximum serum drug concentration [C max] to the MIC) were correlated with in vivo efficacy, as measured by organism numbers in kidney cultures after 96 h of therapy. The kinetics following intraperitoneal anidulafungin dosing in neutropenic infected mice were monitored. Peak levels and AUCs were linear over the 16-fold dose range studied. The drug elimination half-life in serum ranged from 14 to 24 h. Single-dose postantifungal-effect studies demonstrated prolonged suppression of organism regrowth after serum anidulafungin levels had fallen below the MIC. Of the four dosing intervals studied, treatment with the more widely spaced dosing regimens was most efficacious, suggesting the C max/MIC ratio as the PK-PD index most predictive of efficacy. Nonlinear regression analysis suggested that both the C max/MIC and AUC/MIC ratios were strongly predictive of treatment success. Studies were then conducted with 13 additional C. albicans, C. tropicalis, and C. glabrata isolates with various anidulafungin susceptibilities (MICs of anidulafungin for these strains, 0.015 to 2.0 μg/ml) to determine if similar C max/MIC and AUC0-24/MIC ratios for these isolates were associated with efficacy. The anidulafungin exposures associated with efficacy were similar among Candida species.

scholarly journals Temporal analysis of mRNA expression profiles in Orientia infected C3HeB/FeJ mouse

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Chien-Chung Chao ◽  
Ruoting Yang ◽  
Zhiwen Zhang ◽  
Tatyana Belinskaya ◽  
Chye-Teik Chan ◽  
...  
Keyword(s):  
Post Infection ◽  
Mammalian Cells ◽  
Time Course ◽  
Expression Profiles ◽  
Quantitative Polymerase Chain Reaction ◽  
In Vivo Studies ◽  
Coagulation Cascade ◽  
Global Changes

Abstract Background Scrub typhus causes up to 35% mortality if left untreated. One billion people living in the endemic regions are at risk. In spite of its heavy disease burden in some of the most populated areas in the world, there is no vaccine available. Although the disease can be effectively treated by proper antibiotics, timely and accurate diagnosis remains a challenge. Orientia tsutsugamushi infects a variety of mammalian cells in vitro and replicates in the cytoplasm of the infected cells. Microarray analysis has been used extensively to study host-pathogen interactions in in vitro models to understand pathogenesis. However there is a lack of in vivo studies. Results In this study, C3HeB/FeJ (C3H) mice were infected by O. tsutsugamushi via the intraperitoneal route and monitored gene expression at 10 different time points post infection. We observed two distinct types of expression profiles in the genes that we analyzed. There are two valleys (4–18 h and 2–4 days) with low number of differentially expressed genes (DEG) with three peaks with high number of DEG at 2 h, 1-day and 7-day post infection. Further analysis revealed that pathways like complement and coagulation cascade, and blood clotting cascade pathways showed significant global changes throughout entire time course. Real time quantitative Polymerase Chain Reaction (RT-qPCR) confirmed the change of expression for genes involved in complement and coagulation cascade. These results suggested dynamic regulation of the complement and coagulation cascades throughout most of the time post infection while some other specific pathways, such as fatty acid metabolism and tryptophan metabolism, are turned on or off at certain times post infection. Conclusions The findings highlight the complex interconnection among all different biological pathways. It is conceivable that specific pathways such as cell growth control and cell development in the host are affected by Orientia in the initial phase of infection for Orientia to grow intracellularly. Once Orientia is replicating successfully inside the host as infection progresses, the infection could activate pathways involved in cellular immune responses to defend for host cell survival and try to eliminate the pathogen.

scholarly journals Recent strategies in nanodelivery systems for natural products: a review

2021 ◽  
Author(s):  
Giulia Vanti
Keyword(s):  
Natural Products ◽  
Water Solubility ◽  
Molecular Size ◽  
Structural Diversity ◽  
In Vivo Studies ◽  
Biological Targets ◽  
Routes Of Administration ◽  
Rapid Clearance

AbstractNatural products are major molecules for drug discovery due to their structural diversity and their interaction with various biological targets, yet their clinical application is limited by poor water solubility or low lipophilicity, inappropriate molecular size, low dissolution rate and permeation, instability, high metabolic rate and rapid clearance. These issues can be solved by nanomedicine, by improving bioavailability and therapeutic efficacy. Here we review nanocarriers made of polymer or lipid constituents. Specifically, we describe the technological characteristics of each nanosystem, with examples of application to single natural constituents or plant extracts, and possible routes of administration. We report in vitro and in vivo studies and we conclude with the potential advantages of nanodelivery systems in terms of increased stability and solubility, improved biodistribution and efficacy, reduced adverse effects and toxicity.

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