scholarly journals Long-Term Azithromycin Therapy in Cystic Fibrosis Patients: A Study on Drug Levels and Sputum Properties

2004 ◽  
Vol 11 (2) ◽  
pp. 151-155 ◽  
Author(s):  
Ulrich Baumann ◽  
Malcolm King ◽  
Ernst M App ◽  
Shusheng Tai ◽  
Armin König ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Low Dose ◽  
Term Therapy ◽  
High Dose ◽  
Drug Levels ◽  
Diffuse Panbronchiolitis ◽  
Underlying Mechanisms

BACKGROUND:Following reports on the treatment of diffuse panbronchiolitis (DPB), recent studies demonstrate that long term therapy with azithromycin (AZM) is effective in cystic fibrosis (CF) patients. However, the underlying mechanisms remain uncertain. Some macrolides, including AZM, display inhibition of virulence factors and other antipseudomonal effects at subinhibitory levels in vitro.OBJECTIVES:Drug doses used for CF and DPB therapy were investigated to determine whether they achieve corresponding sputum drug levels in CF patients in vivo.METHODS:In an open, prospective study, 14 CF patients with chronic Pseudomonas aeruginosa airway infection received 250 mg AZM either daily ('high dose') or twice weekly ('low dose') for 12 weeks. Viscoelasticity of sputum was assessed by magnetic microrheology.RESULTS:AZM accumulated in sputum by two orders of magnitude over a period of four weeks. In the following steady state, median AZM concentrations in sputum were 9.5 µg/mL (0.6 to 79.3 µg/mL, interquartiles 1.4 to 33.4 µg/mL) and 0.5 µg/mL (range less than 0.1 [below detection level] to 5.2 µg/mL, interquartiles 0.2 to 1.4 µg/mL) in the high and low dose groups, respectively. Viscoelasticity improved in all patients but one.CONCLUSIONS:The findings suggest that antipseudomonal activity has to be considered among the potential mechanisms of macrolide therapy. Further, viscoelasticity may be a valuable parameter in future clinical trials.

scholarly journals 735 Identification of a small molecule that prevents T cell exhaustion using machine learning algorithms paired with high-resolution single cell RNAseq

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A766-A766
Author(s):  
Isabelle Le Mercier ◽  
Sunny Sun ◽  
Dongmei Xiao ◽  
Laura Isacco ◽  
Daniel Treacy ◽  
...  
Keyword(s):  
T Cell ◽  
Low Dose ◽  
Machine Learning Algorithms ◽  
High Dose ◽  
T Cell Exhaustion ◽  
Tcr Signaling ◽  
Compound A ◽  
Cell Exhaustion

BackgroundT cell responses are tightly regulated and require a constant balance of signals during the different stages of their activation, expansion, and differentiation. As a result of chronic antigen exposure, T cells become exhausted in solid tumors, preventing them from controlling tumor growth.MethodsWe identified a transcriptional signature associated with T cell exhaustion in patients with melanoma and used our proprietary machine learning algorithms to predict molecules that would prevent T cell exhaustion and improve T cell function. Among the predictions, an orally available small molecule, Compound A, was highly predicted.ResultsCompound A was tested in an in vitro T cell Exhaustion assay and shown to prevent loss of proliferation and expression of immune checkpoint receptors. Transcriptionally, Compound A-treated cells looked indistinguishable from conventionally expanded, non-exhausted T cells. However, when assessed in a classical T cell activation assay, Compound A demonstrated dose dependent activity. At low dose, Compound A was immuno-stimulatory, allowing cells to divide further by preventing activation induced cell death. At higher doses, Compound A demonstrated immuno-suppressive activity preventing early CD69 upregulation and T cell proliferation. All together, these observations suggest that Compound A prevented exhaustion with a mechanism of action involving TCR signaling inhibition. While cessation of TCR signaling or rest has been recently associated with improved CAR-T efficacy by preventing or reversing exhaustion during the in vitro manufacturing phase, it is unclear if that mechanism would translate in vivo.Compound A was evaluated in the CT26 and MC38 syngeneic mouse models alongside anti-PD1. At low dose Compound A closely recapitulated anti-PD1 mediated cell behavior changes by scRNA-seq and flow cytometry in CT26 mice. At high dose, Compound A led to the accumulation of naive cells in the tumor microenvironment (TME) confirming the proposed mechanism of action. Low dose treatment was ineffective in MC38 mouse model but a pulsed treatment at high dose also recapitulated anti-PD1 activity in most animals. Importantly, we identified a new T cell population responding to anti-PD1 that was particularly increased in the MC38 mouse model; Compound A treatment also impacted this population.ConclusionsThese data confirm that mild TCR inhibition either suboptimal or fractionated can prevent exhaustion in vivo. However, this approach has a very limited window of activity between immuno-modulatory and immuno-suppressive effects, thereby limiting potential clinical benefit. Finally, these results demonstrate that our approach and platform was able to predict molecules that would prevent T cell exhaustion in vivo.

scholarly journals Επικεκαλυμμένες ενδαγγειακές προθέσεις και επαναστένωση μετά από αγγειοπλαστική

2014 ◽  
Author(s):  
Δημήτριος Λυσίτσας
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Heat Shock Protein 70 ◽  
Low Dose ◽  
High Dose ◽  
Hsp 70

Εισαγωγή: Η υπερπλασία του έσω χιτώνα παίζει μείζων ρόλο στην επαναστένωση (in-stentrestenosis). Στην παρούσα μελέτη αξιολογήσαμε in vitro την επίδραση της D-24851(κυτταροτοξική ουσία που σταματά τον κυτταρικό κύκλο στο στάδιο G2-M) στονπολλαπλασιασμό των λείων μυϊκών κυττάρων και μελετήσαμε την ασφάλεια και τηνδραστικότητα μίας ενδαγγειακής πρόθεσης (stent) επικαλυμμένης με πολυμερή ουσία πουαπελευθερώνει την D-24851, στην αναστολή της υπερπλασίας του έσω χιτώνα χωρίς ναεμποδίζει την αναγεννητική ικανότητα του ενδοθηλίου σε in vivo πειραματικό μοντέλο.Υλικό και Μέθοδοι: Γυμνά μεταλλικά stent (n=6), stent επικαλυμμένα μόνο με πολυμερήουσία (polymer-coated, n=7) και stent επικαλυμμένα με πολυμερή ουσία πουαπελευθερώνουν 31±1μg (low-dose, n=7), 216±8 μg (high-dose, n=6) ή 1774±39 μg(extreme-dose, n=5) της D-24851 εμφυτεύτηκαν στις μηριαίες αρτηρίες λευκών New Zealandκουνελιών. Τα πειραματόζωα θυσιάστηκαν στις 28 ημέρες για ιστομορφομετρική ανάλυση.Για την αξιολόγηση της ενδοθηλιακής αναγέννησης στις 90 ημέρες, 12 πειραματόζωαχρησιμοποιήθηκαν για την τοποθέτηση polymer-coated (n=3), low dose (n=3), high dose(n=3) or extreme dose (n=3) ενδαγγειακών προθέσεων.Αποτελέσματα: In vitro η D-24851 αναστέλλει την υπερπλασία των λείων μυϊκών κυττάρωνκαι επάγει την απόπτωση τους χωρίς να αυξάνει την επαγωγή της heat shock protein 70(HSP-70), μία κυτταροπροστατευτική και αντι-αποπτωτική πρωτεΐνη. Η θεραπεία με lowdoseD-24851 stents συνδυάστηκε με 38% (P=0.029) μείωση της υπερπλαστικής περιοχήςτου έσω χιτώνα και 35% (P=0.003) μείωση της επι τοις εκατό στένωσης του αυλού σεσύγκριση με τα γυμνά μεταλλικά stents. Ο τραυματισμός και η φλεγμονή του αρτηριακού τοιχώματος δεν παρουσίασαν σημαντικές διαφορές μεταξύ των ομάδων. Τα επικαλυμμέναμόνο με πολυμερή ουσία stents εμφάνισαν παρόμοια ανάπτυξη νεοιστού σε σύγκριση με ταγυμνά μεταλλικά stents. Ωστόσο, όλες οι ομάδες των stents με D-24851 παρουσίασαν ατελήενδοθηλιοποίηση συγκρινόμενα με τα polymer-coated stents.Συμπεράσματα: Οι επικεκαλυμμένες ενδαγγειακές προσθέσεις με πολυμερή ουσία καιχαμηλη δόση D-24851 μειώνουν σημαντικά την υπερπλασιά του έσω χιτώνα. Λόγω τηςατελούς ενδοθηλιοποίησης, μακράς διάρκειας μελέτες είναι απαραίτητες για ναπιστοποιήσουν ότι η αναστολή του νεοιστού παραμένει και μετά τις 28 ημέρες.

scholarly journals Toll-Like Receptor Signaling in Airborne Burkholderia thailandensis Infection

2009 ◽  
Vol 77 (12) ◽  
pp. 5612-5622 ◽  
Author(s):  
T. Eoin West ◽  
Thomas R. Hawn ◽  
Shawn J. Skerrett
Keyword(s):  
Low Dose ◽  
Inflammatory Responses ◽  
High Dose ◽  
Tlr Signaling ◽  
Necrosis Factor Alpha ◽  
Airborne Infection ◽  
Essential Components ◽  
High Doses

ABSTRACT Melioidosis is a tropical disease endemic in southeast Asia and northern Australia caused by the gram-negative soil saprophyte Burkholderia pseudomallei. Although infection is often systemic, the lung is frequently involved. B. thailandensis is a closely related organism that at high doses causes lethal pneumonia in mice. We examined the role of Toll-like receptors (TLRs), essential components of innate immunity, in vitro and in vivo during murine B. thailandensis pneumonia. TLR2, TLR4, and TLR5 mediate NF-κB activation by B. thailandensis in transfected HEK293 or CHO cells. In macrophages, TLR4 and the adaptor molecule MyD88, but not TLR2 or TLR5, are required for tumor necrosis factor alpha production induced by B. thailandensis. In low-dose airborne infection, TLR4 is needed for early, but not late, bacterial containment, and MyD88 is essential for control of infection and host survival. TLR2 and TLR5 are not necessary to contain low-dose infection. In high-dose airborne infection, TLR2 deficiency confers a slight survival advantage. Lung and systemic inflammatory responses are induced by low-dose inhaled B. thailandensis independently of individual TLRs or MyD88. These findings suggest that redundancy in TLR signaling or other MyD88-dependent pathways may be important in pneumonic B. thailandensis infection but that MyD88-independent mechanisms of inflammation are also activated. TLR signaling in B. thailandensis infection is substantially comparable to signaling induced by virulent B. pseudomallei. These studies provide additional insights into the host-pathogen interaction in pneumonic Burkholderia infection.

scholarly journals Concordance between Thioacetamide-Induced Liver Injury in Rat and Human In Vitro Gene Expression Data

2020 ◽  
Vol 21 (11) ◽  
pp. 4017
Author(s):  
Patric Schyman ◽  
Richard L. Printz ◽  
Shanea K. Estes ◽  
Tracy P. O’Brien ◽  
Masakazu Shiota ◽  
...  
Keyword(s):  
Liver Injury ◽  
Low Dose ◽  
Pearson Correlation ◽  
Organ Injury ◽  
High Dose ◽  
Rna Seq ◽  
Bile Duct Proliferation ◽  
Toxicological Studies

The immense resources required and the ethical concerns for animal-based toxicological studies have driven the development of in vitro and in silico approaches. Recently, we validated our approach in which the expression of a set of genes is uniquely associated with an organ-injury phenotype (injury module), by using thioacetamide, a known liver toxicant. Here, we sought to explore whether RNA-seq data obtained from human cells (in vitro) treated with thioacetamide-S-oxide (a toxic intermediate metabolite) would correlate across species with the injury responses found in rat cells (in vitro) after exposure to this metabolite as well as in rats exposed to thioacetamide (in vivo). We treated two human cell types with thioacetamide-S-oxide (primary hepatocytes with 0 (vehicle), 0.125 (low dose), or 0.25 (high dose) mM, and renal tubular epithelial cells with 0 (vehicle), 0.25 (low dose), or 1.00 (high dose) mM) and collected RNA-seq data 9 or 24 h after treatment. We found that the liver-injury modules significantly altered in human hepatocytes 24 h after high-dose treatment involved cellular infiltration and bile duct proliferation, which are linked to fibrosis. For high-dose treatments, our modular approach predicted the rat in vivo and in vitro results from human in vitro RNA-seq data with Pearson correlation coefficients of 0.60 and 0.63, respectively, which was not observed for individual genes or KEGG pathways.

scholarly journals Efficacy of NS-718, a Novel Lipid Nanosphere-Encapsulated Amphotericin B, againstCryptococcus neoformans

1998 ◽  
Vol 42 (7) ◽  
pp. 1722-1725 ◽  
Author(s):  
Mohammad Ashraf Hossain ◽  
Shigefumi Maesaki ◽  
Hiroshi Kakeya ◽  
Tetsuhiro Noda ◽  
Katsunori Yanagihara ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Antifungal Agent ◽  
Low Dose ◽  
Yeast Cells ◽  
High Dose ◽  
Pulmonary Cryptococcosis ◽  
High Dose Therapy ◽  
Dose Therapy

ABSTRACT In vitro and in vivo efficacies of NS-718, a lipid nanosphere-encapsulated amphotericin B (AMPH-B), have been studied. Of the tested AMPH-B formulations, NS-718 had the lowest MIC forCryptococcus neoformans. In a murine model, low-dose therapy (0.8 mg/kg of body weight) with NS-718 showed higher efficacy than that with AmBisome. High-dose therapy (2.0 mg/kg) with NS-718 was much more effective than those with Fungizone and AmBisome. In mice treated with a high dose of NS-718, only a few yeast cells had grown in lung by 7 days after inoculation. A pharmacokinetic study showed higher concentrations of AMPH-B in lung following administration of NS-718 than after administration of AmBisome. Our results indicated that NS-718, a new AMPH-B formulation, is a promising antifungal agent for treatment of pulmonary cryptococcosis and could be the most effective antifungal agent against C. neoformans infections.

Osteoblast Growth Inhibition by Unfractionated Heparin and by Low Molecular Weight Heparins: An in-vitro Investigation

2002 ◽  
Vol 8 (3) ◽  
pp. 251-255 ◽  
Author(s):  
H. J. Kock ◽  
A. E. Handschin
Keyword(s):  
Molecular Weight ◽  
Unfractionated Heparin ◽  
Cell Cultures ◽  
Term Therapy ◽  
Low Molecular Weight ◽  
High Dose ◽  
Low Molecular Weight Heparins ◽  
In Vitro Investigation

Osteoporosis is a rare but potentially severe complication under high-dose, long-term unfractionated heparin therapy. Low-molecular-weight heparins (LMWHs) have gained increased importance in antithrombotic therapy over the past decade. Whether this heterogeneous group of drugs carries a comparable risk of osteoporosis in long-term application is unknown. In a standardized in vitro model, the effects of 4 different low-molecular-weight heparins (nadroparin, enoxaparin, dalteparin, certoparin) on osteoblast growth were studied at the same dose (50,μg/mL). As control, the effect of unfractionated heparin (Liquemin) was tested on human osteoblasts in vitro at an equal dose. Human osteoblast cell cultures were incubated with equal doses of the heparins, and cell concentrations were measured after 48 and 96 hours. In addition, a fluorescence assay was performed to detect potential cytotoxic effect of heparins on bone cells. In comparison to control groups of non-incubated cell cultures, LMWHs caused a significant inhibition of osteoblast growth (p<0.05). Therefore, the risk of osteoporosis under long-term therapy with high doses of LMWHs cannot be excluded and should be further evaluated in clinical trials.

scholarly journals The Molecular Mechanism of Chronic High-Dose Corticosterone-Induced Aggravation of Cognitive Impairment in APP/PS1 Transgenic Mice

2021 ◽  
Vol 13 ◽  
Author(s):  
Shen-Qing Zhang ◽  
Long-Long Cao ◽  
Yun-Yue Liang ◽  
Pu Wang
Keyword(s):  
Preclinical Model ◽  
High Dose ◽  
Term Administration ◽  
Amyloid Aβ ◽  
Β Amyloid ◽  
Stimulation Of ◽  
Bace 1

Clinical studies have found that some Alzheimer’s disease (AD) patients suffer from Cushing’s syndrome (CS). CS is caused by the long-term release of excess glucocorticoids (GCs) from the adrenal gland, which in turn, impair brain function and induce dementia. Thus, we investigated the mechanism of the effect of corticosterone (CORT) on the development and progression of AD in a preclinical model. Specifically, the plasma CORT levels of 9-month-old APP/PS1 Tg mice were abnormally increased, suggesting an association between GCs and AD. Long-term administration of CORT accelerated cognitive dysfunction by increasing the production and deposition of β-amyloid (Aβ). The mechanism of action of CORT treatment involved stimulation of the expression of BACE-1 and presenilin (PS) 1 in in vitro and in vivo. This observation was confirmed in mice with adrenalectomy (ADX), which had lower levels of GCs. Moreover, the glucocorticoid receptor (GR) mediated the effects of CORT on the stimulation of the expression of BACE-1 and PS1 via the PKA and CREB pathways in neuroblastoma N2a cells. In addition to these mechanisms, CORT can induce a cognitive decline in APP/PS1 Tg mice by inducing apoptosis and decreasing the differentiation of neurons.

scholarly journals In vivo importance of heparan sulfate-binding glycoproteins for murid herpesvirus-4 infection

2009 ◽  
Vol 90 (3) ◽  
pp. 602-613 ◽  
Author(s):  
Laurent Gillet ◽  
Janet S. May ◽  
Philip G. Stevenson
Keyword(s):  
Heparan Sulfate ◽  
Low Dose ◽  
Envelope Glycoproteins ◽  
High Dose ◽  
Cell Binding ◽  
Host Colonization ◽  
Infection Dose ◽  
Herpesvirus 4

Many herpesviruses bind to heparan sulfate (HS). Murid herpesvirus-4 (MuHV-4) does so via its envelope glycoproteins gp70 and gH/gL. MuHV-4 gp150 further regulates an HS-independent interaction to make that HS-dependent too. Cell binding by MuHV-4 virions is consequently strongly HS-dependent. Gp70 and gH/gL show some in vitro redundancy: an antibody-mediated blockade of HS binding by one is well tolerated, whereas a blockade of both severely impairs infection. In order to understand the importance of HS binding for MuHV-4 in vivo, we generated mutants lacking both gL and gp70. As expected, gL−gp70− MuHV-4 showed very poor cell binding. It infected mice at high dose but not at low dose, indicating defective host entry. But once entry occurred, host colonization, which for MuHV-4 is relatively independent of the infection dose, was remarkably normal. The gL−gp70− entry deficit was much greater than that of gL− or gp70− single knockouts. And gp150 disruption, which allows HS-independent cell binding, largely rescued the gL−gp70− cell binding and host entry deficits. Thus, it appeared that MuHV-4 HS binding is important in vivo, principally for efficient host entry.

Sign in / Sign up

Export Citation Format

Share Document