Static Concentrations Research Articles

Measurement of neuro-energetics and neurotransmission in the rat olfactory bulb using 1H and 1H-[13C] NMR spectroscopy.

The olfactory bulb (OB) plays a fundamental role in the sense of smell and has been implicated in several pathologies, including Alzheimer's disease. Despite its importance, high metabolic activity and unique laminar architecture, the OB is not frequently studied using MRS methods, likely due to the small size and challenging location. Here we present a detailed metabolic characterization of OB metabolism, in terms of both static metabolite concentrations using 1H MRS and metabolic fluxes associated with neuro-energetics and neurotransmission by tracing the dynamic 13C flow from intravenously administered [1,6-13C2]-glucose, [2-13C]-glucose and [2-13C]-acetate to downstream metabolites, including [4-13C]-glutamate, [4-13C]-glutamine and [2-13C]-GABA. The unique laminar architecture and associated metabolism of the OB, distinctly different from that of the cerebral cortex, is characterized by elevated GABA and glutamine levels, as well as increased GABAergic and astroglial energy metabolism and neurotransmission. The results show that, despite the technical challenges, high-quality 1H and 1H-[13C] MR spectra can be obtained from the rat OB in vivo. The derived metabolite concentrations and metabolic rates demonstrate a unique metabolic profile for the OB. The metabolic model provides a solid basis for future OB studies on functional activation or pathological conditions.

Ethanol fermentation- and ethylene physiology-related gene expression profiles in Red Delicious apples stored under variable hypoxic conditions and protocols

Dynamic Controlled Atmosphere (DCA) is beneficial in maintaining specific quality parameters but, due to the extreme oxygen levels applied, can cause adverse effects on the fruit by inducing excessive anaerobic metabolism and the production of off-flavors. The metabolic adaptation and responses of apples (Malus domestica Borkh.) cv. Red Delicious to static or dynamic oxygen concentrations (0.3 and 0.8%, with sequential shifts) during cold storage for 7 months were studied by monitoring quality parameters and the expression of genes involved in sugar, fermentative metabolism, and ethylene physiology. Ethanol content reached the highest levels (around 400 mg/kg FW) under 0.3% oxygen concentration and fruit firmness appeared to be reduced in samples accumulating the highest levels of ethanol. Oxygen switch was effective in reducing the ethanol concentrations with timing-dependent variable effects. The expression of fermentative (alcohol dehydrogenase, lactate dehydrogenase, pyruvate decarboxylase) and sugar metabolism (β-amylase; phosphofructokinase; sucrose synthase) genes resulted to be differently affected by the hypoxic conditions imposed, in particular during the early stages of storage. Sucrose synthase expression appeared to be highly sensitive to changes in low oxygen concentration. Ethylene biosynthesis (ACC synthase and oxidase) genes showed marked differences in their expression in relation to the static and dynamic protocols and the hypoxic conditions, as well as six Ethylene Responsive Factors (ERF) genes, some of them possibly involved in the oxygen sensing mechanism operating in fruit tissues.

Penicillin-Binding Proteins and Alternative Dual-Beta-Lactam Combinations for Serious Enterococcus faecalis Infections with Elevated Penicillin MICs.

Ampicillin-ceftriaxone has become a first-line therapy for Enterococcus faecalis endocarditis. We characterized the penicillin-binding protein (PBP) profiles of various E. faecalis strains and tested for synergy to better inform beta-lactam options for the treatment of E. faecalis infections. We assessed the affinity of PBP2B from elevated-MIC strain E. faecalis LS4828 compared to type strain JH2-2 using the fluorescent beta-lactam Bocillin FL. We also characterized pbp4 and pbpA structures and PBP4 and PBP2B expression and used deletion and complementation studies to assess the impact of PBP2B on the levels of resistance. We tested penicillin-susceptible and -resistant E. faecalis isolates against ceftriaxone or ceftaroline combinations with other beta-lactams in 24-h time-kill studies. Two penicillin-susceptible strains (JH2-2 and L2052) had identical pbp sequences and similar PBP expression levels. One reduced-penicillin-susceptibility strain (L2068) had pbp sequences identical to those of the susceptible strains but expressed more PBP4. The second decreased-penicillin-susceptibility strain (LS4828) had amino acid substitutions in both PBP4 and PBP2B and expressed increased quantities of both proteins. PBP2B did not appear to contribute significantly to the elevated beta-lactam MICs. No synergy was demonstrable against the strains with both mutated PBPs and increased expression (L2068 and LS4828). Meropenem plus ceftriaxone or ertapenem plus ceftriaxone demonstrated the most consistent synergistic activity. PBP2B of strain LS4828 does not contribute significantly to reduced penicillin susceptibility. Neither the MIC nor the level of PBP expression correlated directly with the identified synergistic combinations when tested at static subinhibitory concentrations.

Pharmacodynamic Modeling to Evaluate the Impact of Cimetidine, an OCT2 Inhibitor, on the Anticancer Effects of Cisplatin

Despite potent anticancer activity, the clinical utilization of cisplatin is limited due to nephrotoxicity. As Organic Cation Transporter 2 (OCT2) has been shown to be one of the key transporters involved in the uptake of cisplatin into renal proximal tubules, OCT2 inhibitors such as cimetidine have been explored to suppress cisplatin-induced nephrotoxicity. Nonetheless, the impact of OCT2 inhibition or cimetidine on the anti-cancer effects of cisplatin has not been extensively examined. The main objective of the present study was to quantitatively characterize the anticancer effects of cisplatin and cimetidine and determine their nature of interactions in two cancer cell lines, OCT2-negative hepatocellular carcinoma (HCC) cell line, Huh7, and OCT2-positive breast cancer cell line, MDA-MB-468. First, we determined the static concentration-response curves of cisplatin and cimetidine as single agents. Next, with the help of three-dimensional (3D) response surface analyses and a competitive interaction model, we determined their nature of interactions at static concentrations to be modestly synergistic or additive in Huh7 and antagonistic in MDA-MB-468. These results were consistent with the cell-level pharmacodynamic (PD) modeling analysis which leveraged the time-course effects of drugs as single agents and drug combinations. Our developed PD model can be further used to design future preclinical studies to further investigate the cisplatin and cimetidine combinations in different in vitro and in vivo cancer models.

DynH 2 O: Aufbau zur metrologischen Charakterisierung der dynamischen Eigenschaften von Hygrometern

Abstract A novel flow switching setup for the dynamic generation and metrological detection of fast, isolated H2O concentration changes is presented and characterized. Based on this flow setup, very accurate, static H2O concentrations as well as highly dynamic H2O step changes of several 1000 ppmv (µmol/mol) can be generated and repeated. First experiments show that temporal water vapor concentration gradients of up to 10000 ppmv/s can be generated and measured. Based on this setup, a dynamic hygrometer characterization method was developed and demonstrated using a polymer-based hygrometer as device under test (DUT). The polymer hygrometer (with about 180 ppmv/s) proved to be more than 15 times slower than the optical reference hygrometer (with 3000 ppmv/s) and could be modeled and described well with a first order lowpass. To estimate the dynamics of the spatial and temporal H2O-profile, a fast, traversable, local sampling probe was developed and used in combination with a fast, extractive laser hygrometer (called SEALDH-II). The modeling of the H2O distribution in the dynamically operated flow channel enables the calculation of the dynamic concentration at the position of the DUT based on the data of the spatially averaging open-path laser reference hygrometer. In the future, this calculation will be used to determine a transfer function between the optical, open path reference hygrometer and the position of the DUT in order to extract the ideal step response of the DUT from the measured data of the flow channel.

Catalase inhibition by nitric oxide potentiates hydrogen peroxide to trigger catastrophic chromosome fragmentation in Escherichia coli.

Hydrogen peroxide (H2O2, HP) is a universal toxin that organisms deploy to kill competing or invading cells. Bactericidal action of H2O2 presents several questions. First, the lethal H2O2 concentrations in bacterial cultures are 1000x higher than, for example, those calculated for the phagosome. Second, H2O2-alone kills bacteria in cultures either by mode-one, via iron-mediated chromosomal damage, or by mode-two, via unknown targets, but the killing mode in phagosomes is unclear. Third, phagosomal H2O2 toxicity is enhanced by production of nitric oxide (NO), but in vitro studies disagree: some show NO synergy with H2O2 antimicrobial action, others instead report alleviation. To investigate this "NO paradox," we treated Escherichia coli with various concentrations of H2O2-alone or H2O2+NO, measuring survival and chromosome stability. We found that all NO concentrations make sublethal H2O2 treatments highly lethal, via triggering catastrophic chromosome fragmentation (mode-one killing). Yet, NO-alone is not lethal, potentiating H2O2 toxicity by blocking H2O2 scavenging in cultures. Catalases represent obvious targets of NO inhibition, and catalase-deficient mutants are indeed killed equally by H2O2-alone or H2O2+NO treatments, also showing similar levels of chromosome fragmentation. Interestingly, iron chelation blocks chromosome fragmentation in catalase-deficient mutants without blocking H2O2-alone lethality, indicating mode-two killing. In fact, mode-two killing of WT cells by much higher H2O2 concentrations is transiently alleviated by NO, reproducing the "NO paradox." We conclude that NO potentiates H2O2 toxicity by promoting mode-one killing (via catastrophic chromosome fragmentation) by otherwise static low H2O2 concentrations, while transiently suppressing mode-two killing by immediately lethal high H2O2 concentrations.

Design and Optimization of Lug Bracket Assembly

An aircraft is an advanced mechanical structure made by man which has been dominating the skies from the early 19th centuries. It has been used for transportation of cargo/ passengers from one place to another in a shorter period of time. Advances in aeronautics lead to the development of fighter aircrafts with exciting and dominating characteristics. A fighter aircraft is to be designed in such a way that it can withstand heavy loadings on the wing due to its high manoeuvrability. A fighter aircraft is designed to be marginally unstable, which makes control easier and better during manoeuvrability at high speeds, but in this state there is a heavy fluctuating load acting on the wing. The wing is connected to the fuselage using wing fuselage lug attachment bracket. Since the wing is a cantilever structure, the load acting on the wing is concentrated on the hinge (lug bracket assembly). In this paper, a lug bracket is designed according to the standard design procedure and is validated using Finite Element Methods to ensure the static loading capability and stress concentrations in lug bracket. The validated model has been optimized using Altair Optistruct. The optimized model has been validated under static loading condition for the stress concentration and displacement and is compared with initial model in order to study and understand its behaviour under various conditions.

The Polyaminoisoprenyl Potentiator NV716 Revives Old Disused Antibiotics against Intracellular Forms of Infection by Pseudomonas aeruginosa.

Active efflux confers intrinsic resistance to multiple antibiotics in Pseudomonas aeruginosa, including old disused molecules. Beside resistance, intracellular survival is another reason for failure to eradicate bacteria with antibiotics. We evaluated the capacity of polyaminoisoprenyl potentiators (designed as efflux pump inhibitors [EPIs]) NV716 and NV731 compared to PAβN to restore the activity of disused antibiotics (doxycycline, chloramphenicol [substrates for efflux], and rifampin [nonsubstrate]) in comparison with ciprofloxacin against intracellular P. aeruginosa (strains with variable efflux levels) in THP-1 monocytes exposed over 24 h to antibiotics alone (0.003 to 100× MIC) or combined with EPIs. Pharmacodynamic parameters (apparent static concentrations [Cs] and maximal relative efficacy [Emax]) were calculated using the Hill equation of concentration-response curves. PAβN and NV731 moderately reduced (0 to 4 doubling dilutions) antibiotic MICs but did not affect their intracellular activity. NV716 markedly reduced (1 to 16 doubling dilutions) the MIC of all antibiotics (substrates or not for efflux; strains expressing efflux or not); it also improved their relative potency and maximal efficacy (i.e., lower Cs; more negative Emax) intracellularly. In parallel, NV716 reduced the persister fraction in stationary cultures when combined with ciprofloxacin. In contrast to PAβN and NV731, which act only as EPIs against extracellular bacteria, NV716 can resensitize P. aeruginosa to antibiotics whether they are substrates or not for efflux, both extracellularly and intracellularly. This suggests a complex mode of action that goes beyond a simple inhibition of efflux to reduce bacterial persistence. NV716 appears to be a useful adjuvant, including to disused antibiotics with low antipseudomonal activity, to improve their activity, including against intracellular P. aeruginosa.

Metabolic Imaging in Non-Alcoholic Fatty Liver Disease: Applications of Magnetic Resonance Spectroscopy.

Non-alcoholic fatty liver disease (NAFLD) is poised to dominate the landscape of clinical hepatology in the 21st century. Its complex, interdependent aetiologies, non-linear disease progression and uncertain natural history have presented great challenges to the development of effective therapies. Progress will require an integrated approach to uncover molecular mediators, key pathogenic milestones and response to intervention at the metabolic level. The advent of precision imaging has yielded unprecedented insights into these processes. Quantitative imaging biomarkers such as magnetic resonance imaging (MRI), spectroscopy (MRS) and elastography (MRE) present robust, powerful tools with which to probe NAFLD metabolism and fibrogenesis non-invasively, in real time. Specific advantages of MRS include the ability to quantify static metabolite concentrations as well as dynamic substrate flux in vivo. Thus, a vast range of key metabolic events in the natural history of NAFLD can be explored using MRS. Here, we provide an overview of MRS for the clinician, as well as key pathways exploitable by MRS in vivo. Development, optimisation and validation of multinuclear MRS, in combination with other quantitative imaging techniques, may ultimately provide a robust, non-invasive alternative to liver biopsy for observational and longitudinal studies. Through enabling deeper insight into inflammatory and fibrogenic cascades, MRS may facilitate identification of novel therapeutic targets and clinically meaningful endpoints in NAFLD. Its widespread use in future could conceivably accelerate study design, data acquisition and availability of disease-modifying therapies at a population level.

Breast Milk–Derived Retinol Is a Potential Surrogate for Serum in the 13C-Retinol Isotope Dilution Test in Zambian Lactating Women with Vitamin A Deficient and Adequate Status

BackgroundVitamin A (VA) deficiency (VAD) affects ∼19 million pregnant women worldwide. The extent of VAD in Zambian women of reproductive age is unknown owing to lack of survey inclusion or the use of static serum retinol concentrations, a low-sensitivity biomarker. ObjectivesThis cross-sectional study employed isotopic techniques to determine VA status with serum and milk among women aged 18–49 y (n = 197) either lactating with infants aged 0–24 mo or nonlactating with or without infants. MethodsAssistants were trained and piloted data collection. Demographic data, anthropometry, and relevant histories were obtained including malaria and anemia. For retinol isotope dilution (RID), baseline fasting blood and casual breast milk samples were collected before administration of 2.0 μmol 13C2-retinyl acetate and 24-h dietary recalls. On day 14, blood (n = 144) and milk (n = 66) were collected. Prevalence of total liver VA reserves (TLR) ≤0.10 μmol/g was defined as VAD with comparison to the DRI assumption of 0.07 μmol/g as minimally acceptable for North Americans. ResultsWhen a 20% adjustment for dose lost to milk was made in the RID equation for lactation, mean total body VA stores (TBS) for lactating women were 25% lower than for nonlactating women (P < 0.01), which was not the case without adjustment (P = 0.3). Mean ± SD TLR for all women were 0.15 ± 0.11 μmol/g liver. Using retinol purified from breast milk instead of serum for RID analysis yielded similar TBS and TLR, which were highly correlated between methods (P < 0.0001). Serum retinol ≤0.70 μmol/L had 0% sensitivity using either VAD liver cutoff and milk retinol ≤1.0 μmol/L had 42% sensitivity for VAD at 0.10 μmol/g. ConclusionsDetermining accurate VA status among women of reproductive age, especially lactating women, forms a basis for extrapolation to the general population and informing policy development and program implementation.

Impaired high-density lipoprotein function in patients with heart failure

Abstract Background We recently showed that a lower high-density lipoprotein cholesterol (HDL-C) concentration was one of the strongest predictors of death or heart failure (HF) hospitalisation in patients with HF. In a follow-up study, we suggested that this association could be partly explained by HDL proteome composition. However, whether the emerging concept of HDL function contributes to prognosis of HF patients has not been addressed. Methods We measured three key HDL function metrics, namely cholesterol efflux, antioxidative capacity, and anti-inflammatory capacity, at baseline and after 9 months in 446 randomly selected HF patients from BIOSTAT-CHF. Additionally, the relationship between HDL functionality and HDL proteome composition was determined in 86 patients. Results From baseline to 9 months, HDL-C concentrations did not substantially change, but HDL-mediated cholesterol efflux and anti-inflammatory capacity had decreased (both P&amp;lt;0.001). In contrast, antioxidative capacity improved during the 9 months follow-up (P&amp;lt;0.001). Higher HDL-mediated cholesterol efflux was independently associated with lower risk of mortality after adjustment for BIOSTAT risk models and log HDL-C (HR=0.81 [95% CI: 0.71–0.92], P=0.001). Other functionality parameters were not associated with outcome. Several HDL proteins correlated with HDL functionality, mainly with cholesterol efflux, and apolipoprotein A1 emerged as the main protein associated with all three functionality parameters. Conclusions HDL-mediated cholesterol efflux and anti-inflammatory capacity significantly decreased over time in patients with HF. Better baseline cholesterol efflux was prospectively associated with reduced mortality during follow-up independent of HDL-C. Combined these data indicate that HDL function measurements have the potential to provide clinical information beyond static HDL-C concentrations in HF patients. Changes in HDL functionality over time Funding Acknowledgement Type of funding source: Public grant(s) – EU funding. Main funding source(s): European Commission

Extension of Pharmacokinetic/Pharmacodynamic Time-Kill Studies To Include Lipopolysaccharide/Endotoxin Release from Escherichia coli Exposed to Cefuroxime.

The release of inflammatory bacterial products, such as lipopolysaccharide (LPS)/endotoxin, may be increased upon the administration of antibiotics. An improved quantitative understanding of endotoxin release and its relation to antibiotic exposure and bacterial growth/killing may be gained by an integrated analysis of these processes. The aim of this work was to establish a mathematical model that relates Escherichia coli growth/killing dynamics at various cefuroxime concentrations to endotoxin release in vitro Fifty-two time-kill experiments informed bacterial and endotoxin time courses and included both static (0×, 0.5×, 1×, 2×, 10×, and 50× MIC) and dynamic (0×, 15×, and 30× MIC) cefuroxime concentrations. A model for the antibiotic-bacterium interaction was established, and antibiotic-induced bacterial killing followed a sigmoidal Emax relation to the cefuroxime concentration (MIC-specific 50% effective concentration [EC50], maximum antibiotic-induced killing rate [Emax] = 3.26 h-1 and γ = 3.37). Endotoxin release was assessed in relation to the bacterial processes of growth, antibiotic-induced bacterial killing, and natural bacterial death and found to be quantitatively related to bacterial growth (0.000292 endotoxin units [EU]/CFU) and antibiotic-induced bacterial killing (0.00636 EU/CFU). Increased release following the administration of a second cefuroxime dose was described by the formation and subsequent antibiotic-induced killing of filaments (0.295 EU/CFU). Release due to growth was instantaneous, while release due to antibiotic-induced killing was delayed (mean transit time of 7.63 h). To conclude, the in vitro release of endotoxin is related to bacterial growth and antibiotic-induced killing, with higher rates of release upon the killing of formed filaments. Endotoxin release over 24 h is lowest when antibiotic exposure rapidly eradicates bacteria, while increased release is predicted to occur when growth and antibiotic-induced killing occur simultaneously.

Evaluation of pooled human urine and synthetic alternatives in a dynamic bladder infection in vitro model simulating oral fosfomycin therapy

The impact of the bladder environment on fosfomycin activity and treatment response is uncertain. Standard laboratory media does not reflect the biomatrix of urine, where limited nutritional factors are important for growth and antimicrobial kill rates. We compared fosfomycin activity against Enterobacteriaceae in laboratory media, human urine and synthetic alternatives. Sixteen clinical isolates (8-Escherichia coli, 4-Enterobacter cloacae, 4-Klebsiella pneumoniae) were studied with broth microdilution (BMD) susceptibility, static time-kill assays and dynamic testing in a bladder infection model simulating a 3 g oral fosfomycin dose. Mueller-Hinton broth (MHB) with and without 25 mg/L glucose-6-phosphate (G6P), pooled midstream urine (MSU), pooled 24 h urine collection (24 U), artificial urine medium (AUM) and synthetic human urine (SHU) were compared. BMD susceptibility, bacterial growth and response to static fosfomycin concentrations in urine were best matched with SHU and were distinctly different when tested in MHB with G6P. Fosfomycin exposure in the bladder infection model was accurately reproduced (bias 4.7 ± 6.2%). Under all media conditions, 8 isolates (2-E. coli, 2-E. cloacae, 4-K. pneumoniae) re-grew and 4 isolates (4-E. coli) were killed. The remaining isolates (2-E. coli, 2-E. cloacae) re-grew variably in urine and synthetic media. Agar dilution MIC failed to predict re-growth, whereas BMD MIC in media without G6P performed better. Emergence of resistance was restricted in synthetic media. Overall, SHU provided the best substitute for urine for in vitro modelling of antimicrobial treatment of uropathogens, and these data have broader utility for improved preclinical testing of antimicrobials for urinary tract infections.

Controlled pharmacokinetic anti-cancer drug concentration profiles lead to growth inhibition of colorectal cancer cells in a microfluidic device.

We present a microfluidic device to expose cancer cells to a dynamic, in vivo-like concentration profile of a drug, and quantify efficacy on-chip. About 30% of cancer patients receive drug therapy. In conventional cell culture experiments drug efficacy is tested under static concentrations, e.g. 1 μM for 48 hours, whereas in vivo, drug concentration follows a pharmacokinetic profile with an initial peak and a decline over time. With the rise of microfluidic cell culture models, including organs-on-chips, there are opportunities to more realistically mimic in vivo-like concentrations. Our microfluidic device contains a cell culture chamber and a drug-dosing channel separated by a transparent membrane, to allow for shear stress-free drug exposure and label-free growth quantification. Dynamic drug concentration profiles in the cell culture chamber were controlled by continuously flowing controlled concentrations of drug in the dosing channel. The control over drug concentrations in the cell culture chambers was validated with fluorescence experiments and numerical simulations. Exposure of HCT116 colorectal cancer cells to static concentrations of the clinically used drug oxaliplatin resulted in a sensible dose-effect curve. Dynamic, in vivo-like drug exposure also led to statistically significant lower growth compared to untreated control. Continuous exposure to the average concentration of the in vivo-like exposure seems more effective than exposure to the peak concentration (Cmax) only. We expect that our microfluidic system will improve efficacy prediction of in vitro models, including organs-on-chips, and may lead to future clinical optimization of drug administration schedules.

Design analysis of low pressure distillation column for cryogenic air separation

Cryogenic air separation units are widely used in industry, which consume a large energy and need to produce a huge amount of need of nitrogen, oxygen and argon products with high purity. High purity distillation columns are critical unit operations in cryogenic air separation plants. In this paper the low pressure distillation column is investigated by using a steady state model. The first principles mathematic model of the column is firstly developed, and the pressure, temperature and static liquid nitrogen, oxygen and argon concentrations in the upper column are presented. The obtained results give important information on the variation of temperature, pressure, component concentrations and molar flows within the distillation column. The study highlighted the importance of considering air as ternary mixture. The separation process performance is significantly influenced by the location of side draw of argon and reflux ratio at the top of the column

Influence of pH on the activity of finafloxacin against extracellular and intracellular Burkholderia thailandensis, Yersinia pseudotuberculosis and Francisella philomiragia and on its cellular pharmacokinetics in THP-1 monocytes

ObjectivesBurkholderia pseudomallei, Yersinia pestis and Francisella tularensis are facultative intracellular bacteria causing life-threatening infections. We have (a) compared the activity of finafloxacin (a fluoroquinolone in development showing improved activity at acidic pH) with that of ciprofloxacin, levofloxacin and imipenem against the extracellular and intracellular (THP-1 monocytes) forms of infection by attenuated surrogates of these species (B. thailandensis, Y. pseudotuberculosis, F. philomiragia) and (b) assessed finafloxacin cellular pharmacokinetics (accumulation, distribution, efflux). MethodsBacteria in broth or in infected monocytes were exposed to antibiotics at pH 7.4 or 5.5 for 24 hr. Maximal relative efficacies (Emax) and static concentrations (Cs) were calculated using the Hill equation (concentration–response curves). Finafloxacin pharmacokinetics in cells at pH 7.4 or 5.5 was investigated using 14C-labelled drug. ResultsExtracellularly, all drugs sterilized the cultures, with finafloxacin being two to six times more potent at acidic pH. Intracellularly, Emax reached the limit of detection (4–5 log10 cfu decrease) for finafloxacin against all species, but only against B. thailandensis and F. philomiragia for ciprofloxacin and levofloxacin, while imipenem caused less than 2 log10 cfu decrease for all species. At acid pH, Cs shifted to two to five times lower values for finafloxacin and to one to four times higher values for the other drugs. Finafloxacin accumulated in THP-1 cells by approximately fivefold at pH 7.4 but up to 20-fold at pH 5.5, and distributed in the cytosol. ConclusionsFluoroquinolones have proven to be effective in reducing the intracellular reservoirs of B. thailandensis, Y. pseudotuberculosis and F. philomiragia, with finafloxacin demonstrating an additional advantage in acidic environments.

The emerging contaminant 3,3′-dichlorobiphenyl (PCB-11) impedes Ahr activation and Cyp1a activity to modify embryotoxicity of Ahr ligands in the zebrafish embryo model (Danio rerio)

3,3′-dichlorobiphenyl (PCB-11) is an emerging PCB congener widely detected in environmental samples and human serum, but its toxicity potential is poorly understood. We assessed the effects of three concentrations of PCB-11 on embryotoxicity and Aryl hydrocarbon receptor (Ahr) pathway interactions in zebrafish embryos (Danio rerio). Wildtype AB or transgenic Tg(gut:GFP) strain zebrafish embryos were exposed to static concentrations of PCB-11 (0, 0.2, 2, or 20 μM) from 24 to 96 h post fertilization (hpf), and gross morphology, Cytochrome P4501a (Cyp1a) activity, and liver development were assessed via microscopy. Ahr interactions were probed via co-exposures with PCB-126 or beta-naphthoflavone (BNF). Embryos exposed to 20 μM PCB-11 were also collected for PCB-11 body burden, qRT-PCR, RNAseq, and histology. Zebrafish exposed to 20 μM PCB-11 absorbed 0.18% PCB-11 per embryo at 28 hpf and 0.61% by 96 hpf, and their media retained 1.36% PCB-11 at 28 hpf and 0.84% at 96 hpf. This concentration did not affect gross morphology, but altered the transcription of xenobiotic metabolism and liver development genes, impeded liver development, and increased hepatocyte vacuole formation. In co-exposures, 20 μM PCB-11 prevented deformities caused by PCB-126 but exacerbated deformities in co-exposures with BNF. This study suggests that PCB-11 can affect liver development, act as a partial agonist/antagonist of the Ahr pathway, and act as an antagonist of Cyp1a activity to modify the toxicity of compounds that interact with the Ahr pathway.

In vitro activity of voriconazole and amphotericin B against Candida albicans, Candida krusei, and Cryptococcus neoformans in human cerebrospinal fluid

PurposeFungal central nervous system (CNS) infections show a high mortality rate and only a few antifungal agents are available to treat these infections. We hypothesize that the different biochemical properties of human cerebrospinal fluid (CSF) compared to the standard growth medium lead to the altered activity of antifungal agents in CSF. We investigated the in vitro activity of two of these agents, i.e., amphotericin B (AmB) and voriconazole (VOR), against three different fungi in CSF in comparison to sabouraud-dextrose broth (SDB).MethodsCSF samples from patients who did not receive any antibiotics were collected. Time-kill curves were performed in CSF and SDB using static antibiotic concentrations of AmB and VOR against ATCC strains of Candida albicans, Candida krusei, and Cryptococcus neoformans.ResultsIn our experiments, both AmB and VOR showed superior activity in SDB compared to CSF. Nevertheless, AmB achieved fungicidal activity in CSF after 24 h against all test strains. Voriconazole only achieved fungistatic activity against C. albicans and C. neoformans in CSF.ConclusionsIn summary, our data demonstrate that growth of fungal pathogens but even more importantly activity of antifungal agents against Candida and Cryptococcus species can differ significantly in CSF compared to the standard growth medium. Both findings should be taken into consideration when applying PK/PD simulations to fungal infections of the CNS.

Calcium/Phosphate Solubility Curves for Premasol and Trophamine Pediatric Parenteral Nutrition Formulations.

Calcium and phosphate incompatibility in parenteral nutrition formulations remains a critical concern for patient safety. This study examined calcium phosphate solubility for 2-in-1 admixtures prepared using 2 commercially available pediatric amino acid solutions (Premasol, Baxter Healthcare Corp; or Trophamine, B. Braun Medical Inc), applying identical test methods, storage conditions, and acceptance criteria. Parenteral 2-in-1 admixtures included amino acid; dextrose; static concentrations of sodium, potassium, and magnesium, and varying concentrations of calcium (0-60 mEq/L), phosphate (15-50 mmol/L), and cysteine. Three replicate samples were stored for 48 hours at 40°C ± 2°C and then visually inspected for particulate matter, evaluated for subvisible particulate matter, when particulate matter was noted, microscopic examination was performed to confirm the presence of calcium phosphate crystals. Pass criteria were: all replicates free of visible particulate matter related to calcium phosphate crystals and particle counts below US Pharmacopeia <788> limits. Premasol and Trophamine generated identical calcium phosphate curves for 2% amino acid formulations containing 20% dextrose with/without cysteine, and similar curves for the 1% or 3% amino acid formulations containing 10% or 20% dextrose with/without cysteine. Calcium phosphate particles were identified in failed samples by scanning electron microscopy/energy dispersive X-ray spectroscopy. Calcium phosphate solubility was higher in formulations containing cysteine 40 mg/g amino acid vs. cysteine 20 mg/g amino acid and in cysteine 20 mg/g amino acid vs. no cysteine. Admixtures made with 1%, 2%, or 3% Premasol or Trophamine have essentially equivalent calcium phosphate solubility curves when tested with identical methods, storage conditions, and acceptance criteria.

Pengaruh Perbandingan Jumlah Starter dan Konsentrasi Agar pada Pembuatan Yogurt dari Sari Biji Nangka

The aim of this study to determine the effect of adding the amount of Starter and Agar concentration to yogurt of jackfruit seed juice. Total of Starters (S) consisting of 4 levels, namely: S 1 = 2%, S 2 = 4%, S 3 = 6% and S 4 = 8%. The second factor is Concentration of Agar (A) which consists of 4 levels, namely: A 0 = 0%, A 1 = 0.3%, A 2 = 0.6% and A 3 = 0.9%. Parameters observed included: yield, TSS, pH, organoleptics (color, taste, and texture). The results of statistical analysis showed that the number of static concentrations had a very significant effect (P <0.01) on yield, TSS, pH and taste, but did not differ significantly (P <0.05) on color and texture. The amount of agar concentration had a very significant effect (P <0.01) on yield, TSS and texture, but it was not significantly different (P <0.05) on pH, color and taste.