High-dose rifampicin kills persisters, shortens treatment duration, and reduces relapse rate in vitro and in vivo

SummaryThe significance of platelet β-adrenoceptors for platelet responses to adrenergic stimuli in vivo and in vitro was studied in healthy volunteers. Low dose infusion of the β-adrenoceptor agonist isoprenaline decreased platelet aggregability in vivo as measured by ex vivo filtragometry. Infusion of adrenaline, a mixed α- and β-adrenoceptor agonist, increased platelet aggregability in vivo markedly, as measured by ex vivo filtragometry and plasma β-thromboglobulin levels. Adrenaline levels were 3–4 nM in venous plasma during infusion. Both adrenaline and high dose isoprenaline elevated plasma von Willebrand factor antigen levels β-Blockade by propranolol did not alter our measures of platelet aggregability at rest or during adrenaline infusions, but inhibited adrenaline-induced increases in vWf:ag. In a model using filtragometry to assess platelet aggregability in whole blood in vitro, propranolol enhanced the proaggregatory actions of 5 nM, but not of 10 nM adrenaline. The present data suggest that β-adrenoceptor stimulation can inhibit platelet function in vivo but that effects of adrenaline at high physiological concentrations are dominated by an α-adrenoceptor mediated proaggregatory action.

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Methylprednisolone on circulating eicosanoids and vasomotor tone after endotoxin

Journal of Applied Physiology ◽

10.1152/jappl.1986.61.1.185 ◽

1986 ◽

Vol 61 (1) ◽

pp. 185-191 ◽

Cited By ~ 11

Author(s):

C. A. Hales ◽

R. D. Brandstetter ◽

C. F. Neely ◽

M. B. Peterson ◽

D. Kong ◽

...

Keyword(s):

Blood Pressure ◽

Vascular Resistance ◽

Systemic Blood Pressure ◽

Physiological Effect ◽

High Dose ◽

Systemic Blood ◽

Eicosanoid Production ◽

Circulating Levels

Acute pulmonary and systemic vasomotor changes induced by endotoxin in dogs have been related, at least in part, to the production of eicosanoids such as the vasoconstrictor thromboxane and the vasodilator prostacyclin. Steroids in high doses, in vitro, inhibit activation of phospholipase A2 and prevent fatty acid release from cell membranes to enter the arachidonic acid cascade. We, therefore, administered methylprednisolone (40 mg/kg) to dogs to see if eicosanoid production and the ensuing vasomotor changes could be prevented after administration of 150 micrograms/kg of endotoxin. The stable metabolites of thromboxane B2 (TxB2) and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) were measured by radioimmunoassay. Methylprednisolone by itself did not alter circulating eicosanoids but when given 2.5 h before endotoxin not only failed to inhibit endotoxin-induced eicosanoid production but actually resulted in higher circulating levels of 6-keto-PGF1 alpha (P less than 0.05) compared with animals receiving endotoxin alone. Indomethacin prevented the steroid-enhanced concentrations of 6-keto-PGF1 alpha after endotoxin and prevented the greater fall (P less than 0.05) in systemic blood pressure and systemic vascular resistance with steroid plus endotoxin than occurred with endotoxin alone. Administration of methylprednisolone immediately before endotoxin resulted in enhanced levels (P less than 0.05) of both TxB2 and 6-keto-PGF1 alpha but with a fall in systemic blood pressure and vascular resistance similar to the animals pretreated by 2.5 h. In contrast to the early steroid group in which all of the hypotensive effect was due to eicosanoids, in the latter group steroids had an additional nonspecific effect. Thus, in vivo, high-dose steroids did not prevent endotoxin-induced increases in eicosanoids but actually increased circulating levels of TxB2 and 6-keto-PGF1 alpha with a physiological effect favoring vasodilation.

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Effect of Synchronous Versus Sequential Regimens on the Pharmacokinetics and Biodistribution of Regorafenib with Irradiation

Pharmaceutics ◽

10.3390/pharmaceutics13030386 ◽

2021 ◽

Vol 13 (3) ◽

pp. 386

Author(s):

Tung-Hu Tsai ◽

Yu-Jen Chen ◽

Li-Ying Wang ◽

Chen-Hsi Hsieh

Keyword(s):

Stereotactic Body Radiation Therapy ◽

In Vivo Studies ◽

Control Group ◽

High Dose ◽

Dependent Manner ◽

Hep G2 ◽

Time Curve ◽

Dose Dependent

This study was performed to evaluate the interaction between conventional or high-dose radiotherapy (RT) and the pharmacokinetics (PK) of regorafenib in concurrent or sequential regimens for the treatment of hepatocellular carcinoma. Concurrent and sequential in vitro and in vivo studies of irradiation and regorafenib were designed. The interactions of RT and regorafenib in vitro were examined in the human hepatoma Huh-7, HA22T and Hep G2 cell lines. The RT–PK phenomenon and biodistribution of regorafenib under RT were confirmed in a free-moving rat model. Regorafenib inhibited the viability of Huh-7 cells in a dose-dependent manner. Apoptosis in Huh-7 cells was enhanced by RT followed by regorafenib treatment. In the concurrent regimen, RT decreased the area under the concentration versus time curve (AUC)regorafenib by 74% (p = 0.001) in the RT2 Gy × 3 fraction (f’x) group and by 69% (p = 0.001) in the RT9 Gy × 3 f’x group. The AUCregorafenib was increased by 182.8% (p = 0.011) in the sequential RT2Gy × 1 f’x group and by 213.2% (p = 0.016) in the sequential RT9Gy × 1 f’x group. Both concurrent regimens, RT2Gy × 3 f’x and RT9Gy × 3 f’x, clearly decreased the biodistribution of regorafenib in the heart, liver, lung, spleen and kidneys, compared to the control (regorafenib × 3 d) group. The concurrent regimens, both RT2Gy × 3 f’x and RT9Gy × 3 f’x, significantly decreased the biodistribution of regorafenib, compared with the control group. The PK of regorafenib can be modulated both by off-target irradiation and stereotactic body radiation therapy (SBRT).

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Translational Research in FLASH Radiotherapy—From Radiobiological Mechanisms to In Vivo Results

Biomedicines ◽

10.3390/biomedicines9020181 ◽

2021 ◽

Vol 9 (2) ◽

pp. 181

Author(s):

Loredana G. Marcu ◽

Eva Bezak ◽

Dylan D. Peukert ◽

Puthenparampil Wilson

Keyword(s):

Dose Rate ◽

High Dose Rate ◽

Current Status ◽

Therapeutic Window ◽

High Dose ◽

Linear Accelerators ◽

Radiation Delivery ◽

Tissue Sparing

FLASH radiotherapy, or the administration of ultra-high dose rate radiotherapy, is a new radiation delivery method that aims to widen the therapeutic window in radiotherapy. Thus far, most in vitro and in vivo results show a real potential of FLASH to offer superior normal tissue sparing compared to conventionally delivered radiation. While there are several postulations behind the differential behaviour among normal and cancer cells under FLASH, the full spectra of radiobiological mechanisms are yet to be clarified. Currently the number of devices delivering FLASH dose rate is few and is mainly limited to experimental and modified linear accelerators. Nevertheless, FLASH research is increasing with new developments in all the main areas: radiobiology, technology and clinical research. This paper presents the current status of FLASH radiotherapy with the aforementioned aspects in mind, but also to highlight the existing challenges and future prospects to overcome them.

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CD44 Targeted Nanomaterials for Treatment of Triple-Negative Breast Cancer

Cancers ◽

10.3390/cancers13040898 ◽

2021 ◽

Vol 13 (4) ◽

pp. 898

Author(s):

Ghazal Nabil ◽

Rami Alzhrani ◽

Hashem Alsaab ◽

Mohammed Atef ◽

Samaresh Sau ◽

...

Keyword(s):

Breast Cancer ◽

Triple Negative Breast Cancer ◽

Triple Negative ◽

In Vivo Studies ◽

High Dose ◽

Luminal A ◽

Combination Strategy ◽

Ongoing Research

Identified as the second leading cause of cancer-related deaths among American women after lung cancer, breast cancer of all types has been the focus of numerous research studies. Even though triple-negative breast cancer (TNBC) represents 15–20% of the number of breast cancer cases worldwide, its existing therapeutic options are fairly limited. Due to the pivotal role of the presence/absence of specific receptors to luminal A, luminal B, HER-2+, and TNBC in the molecular classification of breast cancer, the lack of these receptors has accounted for the aforementioned limitation. Thereupon, in an attempt to participate in the ongoing research endeavors to overcome such a limitation, the conducted study adopts a combination strategy as a therapeutic paradigm for TNBC, which has proven notable results with respect to both: improving patient outcomes and survivability rates. The study hinges upon an investigation of a promising NPs platform for CD44 mediated theranostic that can be combined with JAK/STAT inhibitors for the treatment of TNBC. The ability of momelotinib (MMB), which is a JAK/STAT inhibitor, to sensitize the TNBC to apoptosis inducer (CFM-4.16) has been evaluated in MDA-MB-231 and MDA-MB-468. MMB + CFM-4.16 combination with a combination index (CI) ≤0.5, has been selected for in vitro and in vivo studies. MMB has been combined with CD44 directed polymeric nanoparticles (PNPs) loaded with CFM-4.16, namely CD44-T-PNPs, which selectively delivered the payload to CD44 overexpressing TNBC with a significant decrease in cell viability associated with a high dose reduction index (DRI). The mechanism underlying their synergism is based on the simultaneous downregulation of P-STAT3 and the up-regulation of CARP-1, which has induced ROS-dependent apoptosis leading to caspase 3/7 elevation, cell shrinkage, DNA damage, and suppressed migration. CD44-T-PNPs showed a remarkable cellular internalization, demonstrated by uptake of a Rhodamine B dye in vitro and S0456 (NIR dye) in vivo. S0456 was conjugated to PNPs to form CD44-T-PNPs/S0456 that simultaneously delivered CFM-4.16 and S0456 parenterally with selective tumor targeting, prolonged circulation, minimized off-target distribution.

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Reduced High-Dose Radiation-Induced Residual Genotoxic Damage by Induction of Radioadaptive Response and Prophylactic Mild Dietary Restriction in Mice

Dose-Response ◽

10.1177/1559325820982166 ◽

2021 ◽

Vol 19 (1) ◽

pp. 155932582098216

Author(s):

Bing Wang ◽

Kaoru Tanaka ◽

Takanori Katsube ◽

Kouichi Maruyama ◽

Yasuharu Ninomiya ◽

...

Keyword(s):

Dietary Restriction ◽

High Dose ◽

Cancer Treatments ◽

Hematopoietic Stem ◽

Beneficial Effects ◽

Radiation Induced ◽

Potential Strategy ◽

Higher Doses

Radioadaptive response (RAR) describes a phenomenon in a variety of in vitro and in vivo systems that a low-dose of priming ionizing radiation (IR) reduces detrimental effects of a subsequent challenge IR at higher doses. Among in vivo investigations, studies using the mouse RAR model (Yonezawa Effect) showed that RAR could significantly extenuate high-dose IR-induced detrimental effects such as decrease of hematopoietic stem cells and progenitor cells, acute radiation hematopoietic syndrome, genotoxicity and genomic instability. Meanwhile, it has been demonstrated that diet intervention has a great impact on health, and dietary restriction shows beneficial effects on numerous diseases in animal models. In this work, by using the mouse RAR model and mild dietary restriction (MDR), we confirmed that combination of RAR and MDR could more efficiently reduce radiogenotoxic damage without significant change of the RAR phenotype. These findings suggested that MDR may share some common pathways with RAR to activate mechanisms consequently resulting in suppression of genotoxicity. As MDR could also increase resistance to chemotherapy and radiotherapy in normal cells, we propose that combination of MDR, RAR, and other cancer treatments (i.e., chemotherapy and radiotherapy) represent a potential strategy to increase the treatment efficacy and prevent IR risk in humans.

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Preclinical Pharmacokinetics of C118P, a Novel Prodrug of Microtubules Inhibitor and Its Metabolite C118 in Mice, Rats, and Dogs

Molecules ◽

10.3390/molecules23112883 ◽

2018 ◽

Vol 23 (11) ◽

pp. 2883 ◽

Cited By ~ 3

Author(s):

Cang Zhang ◽

Xiaolan Zhang ◽

Guangji Wang ◽

Ying Peng ◽

Xueyuan Zhang ◽

...

Keyword(s):

Clinical Development ◽

High Dose ◽

Protein Inhibitor ◽

Promising Candidate ◽

Preclinical Pharmacokinetics ◽

Tumor Bearing ◽

Microtubule Protein ◽

Further Development

C118P, a phosphate prodrug of C118, which is a novel microtubule protein inhibitor, is currently under Phase I clinical development in China for treating ovarian cancer and lung cancer. The preclinical pharmacokinetics of prodrug C118P and its metabolite C118 were extensively characterized in vivo in mice, rats, and dogs and in vitro to support the further development of C118P. The preclinical tissue distribution and excretion were investigated in rats. Plasma protein binding in mice, rat, and human, and hepatic microsomal metabolic stability in mice, rat, dog, monkey, and human, were also evaluated. The (AUC0-inf) and C30s of C118P at 50 mg/kg in rats and 6 mg/kg in dogs, and the C2min of C118 at 6 mg/kg in dogs increased less than the dosage increase, suggested nonlinear pharmacokinetic occurred at high dose. As a prodrug, C118P can be quickly hydrolyzed into C118 after an intravenous administration. The unbound C118 in plasma is slightly higher than C118P. C118P can hardly penetrate the tissue, while C118 can distribute widely into tissues. In tumor-bearing nude mice, the concentration of C118 is high in lung, ovary, and tumor, with an extended half-life in tumor. C118P is a promising candidate prodrug for further clinical development.

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2562. Re-Appraisal of Aminoglycoside (AG) Susceptibility Testing Breakpoints Based on the Application of Pharmacokinetics–Pharmacodynamics (PK-PD) and Contemporary Microbiology Surveillance Data

Open Forum Infectious Diseases ◽

10.1093/ofid/ofy209.170 ◽

2018 ◽

Vol 5 (suppl_1) ◽

pp. S71-S71 ◽

Cited By ~ 4

Author(s):

Sujata M Bhavnani ◽

Nikolas J Onufrak ◽

Jeffrey P Hammel ◽

David R Andes ◽

John S Bradley ◽

...

Keyword(s):

Susceptibility Testing ◽

Surveillance Data ◽

Simulated Patients ◽

High Dose ◽

Target Attainment ◽

In Vitro Susceptibility ◽

Population Pk ◽

Dosing Regimens

Abstract Background Resistance to AGs and numerous other classes continues to emerge. To ensure that susceptibility is accurately characterized and that clinicians have reliable data to select effective agents, appropriate in vitro susceptibility testing interpretive criteria (susceptible breakpoints [BKPTs]) are crucial to ensure optimal patient care. Recently, USCAST, the USA voice to EUCAST/EMA, evaluated the BKPTs for the 3 most commonly used AGs, gentamicin, tobramycin, and amikacin [Bhavnani et al., IDWeek 2016; P-1977]. As a result of consultation from interested parties, which included evaluating AG dosing regimens provided in the US-FDA product package inserts and simulated patients with varying creatinine clearance, these BKPTS were reassessed. Methods Data sources considered included longitudinal US reference MIC distributions using in vitro surveillance data collected over 18 years, QC performance (MIC, disk diffusion), population pharmacokinetics (PK), and in vivo PK-PD models. Using population PK models, PK-PD targets for efficacy and Monte Carlo simulation, percent probabilities of PK-PD target attainment by MIC after administration of traditional and extended interval AG dosing regimens were evaluated among simulated patients. Epidemiological cut-off and PK-PD BKPTs were considered when recommending BKPTs for AG–pathogen pairs. Results An example of PK-PD target attainment analysis output is provided in Figure 1 and a subset of recommended AG BKPTs for 3 pathogens is shown in Table 1. Updated USCAST BKPTs, which were based on the application of population PK and PK-PD models, simulation techniques, and contemporary MIC distribution statistics, are generally lower than those of EUCAST/EMA, USA-FDA, and CLSI. Adequate PK-PD target attainment was not achieved for some AG-pathogen pairs, even when high-dose AG dosing regimens and PK-PD targets for stasis were evaluated (e.g., gentamicin vs. P. aeruginosa; amikacin vs. S. aureus). Conclusion These revised AG BKPT recommendations, which will be made freely available to EUCAST, USA-FDA, and CLSI, will be finalized after considering comments from additional interested stakeholders. This process will be followed in an effort to bring harmonization to global BKPTs for AGs. Disclosures All authors: No reported disclosures.

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Preclinical Evaluation of a Bone-Marrow Autograft Culture Procedure for Generating Lymphokine-Activated Killer Cells in Vitro

Canadian Journal of Infectious Diseases ◽

10.1155/1992/234936 ◽

1992 ◽

Vol 3 (suppl b) ◽

pp. 123-127 ◽

Cited By ~ 3

Author(s):

Hans-Georg Klingemann ◽

Heather Deal ◽

Dianne Reid ◽

Connie J Eaves

Keyword(s):

Bone Marrow ◽

Calf Serum ◽

Cell Activity ◽

Hematopoietic Cells ◽

Lak Cells ◽

High Dose ◽

Lymphokine Activated Killer Cells ◽

Lak Cell

Despite the use of high dose chemoradiotherapy for the treatment of acute leukemia. relapse continues to be a major cause of death in patients given an autologous bone marrow transplant. Further augmentation of pretransplant chemotherapy causes life threatening toxicity to nonhematopoietic tissues and the effectiveness of currently available ex vivo purging methods in reducing the relapse rate is unclear. Recently, data from experimental models have suggested that bone marrow-derived lymphokine (IL-2)-activated killer (BM-LAK) cells might be used to eliminate residual leukemic cells both in vivo and in vitro. To evaluate this possibility clinically, a procedure was developed for culturing whole marrow harvests with IL-2 prior to use as autografts, and a number of variables examined that might affect either the generation of BM-LAK cells or the recovery of the primitive hematopoietic cells. The use of Dexter long term culture (LTC) conditions, which expose the cells to horse serum and hydrocortisone. supported LAK cell generation as effectively as fetal calf serum (FCS) -containing medium in seven-day cultures. Maintenance of BM-LAK cell activity after a further seven days of culture in the presence of IL-2 was also tested. As in the clinical setting. patients would receive IL-2 in vivo for an additional week immediately following infusion of the cultured marrow autograft. Generation ofBM-LAK activity was dependent on the presence of IL-2 and could be sustained by further incubation in medium containing IL-2. Primitive hematopoietic cells were quantitated by measuring the number of in vitro colony-forming progenitors produced after five weeks in secondary Dexter-type LTC. Maintenance of these 'LTC-initiating cells' was unaffected by lL-2 in the culture medium. These results suggest that LAK cells can be generated efficien tly in seven-day marrow autograft cultures containing IL-2 under conditions that allow the most primitive human hematopoietic cells currently detectable to be maintained.

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Tumor Suppressor Function of miR-127-3p and miR-376a-3p in Osteosarcoma Cells

Cancers ◽

10.3390/cancers11122019 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2019 ◽

Cited By ~ 6

Author(s):

Joerg Fellenberg ◽

Burkhard Lehner ◽

Heiner Saehr ◽

Astrid Schenker ◽

Pierre Kunz

Keyword(s):

Tumor Suppressor ◽

Therapeutic Strategies ◽

High Dose ◽

Osteosarcoma Cell ◽

Tumor Suppressor Function ◽

Osteosarcoma Cells ◽

Aberrant Expression ◽

Suppressor Function

Since the introduction of high-dose chemotherapy about 35 years ago, survival rates of osteosarcoma patients have not been significantly improved. New therapeutic strategies replacing or complementing conventional chemotherapy are therefore urgently required. MicroRNAs represent promising targets for such new therapies, as they are involved in the pathology of multiple types of cancer, and aberrant expression of several miRNAs has already been shown in osteosarcoma. In this study, we identified silencing of miR-127-3p and miR-376a-3p in osteosarcoma cell lines and tissues and investigated their role as potential tumor suppressors in vitro and in vivo. Transfection of osteosarcoma cells (n = 6) with miR-127-3p and miR-376a-3p mimics significantly inhibited proliferation and reduced the colony formation capacity of these cells. In contrast, we could not detect any influence of miRNA restoration on cell cycle and apoptosis induction. The effects of candidate miRNA restoration on tumor engraftment and growth in vivo were analyzed using a chicken chorioallantoic membrane (CAM) assay. Cells transfected with mir-127-3p and miR-376a-3p showed reduced tumor take rates and tumor volumes and a significant decrease of the cumulative tumor volumes to 41% and 54% compared to wildtype cells. The observed tumor suppressor function of both analyzed miRNAs indicates these miRNAs as potentially valuable targets for the development of new therapeutic strategies for the treatment of osteosarcoma.

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