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Background: Tumor aggressiveness and therapeutic response are influenced not only by cancer cells but also by the extracellular matrix in tumor microenvironment, which can be quantified by extracellular volume (ECV) fraction derived from dual-energy CT (DECT). We aimed to investigate the feasibility of using routine chest DECT-derived ECV fraction for the characterization of breast tumor, compared to apparent diffusion coefficient (ADC) and validated against histopathological findings.Methods: The ECV fraction and ADC value were retrospectively assessed in patients with breast tumor using routine chest DECT and breast MRI, respectively. The diagnostic performance in predicting the histopathological characteristics [benign vs. malignant, invasive carcinoma vs. ductal carcinoma in situ (DCIS)], immunohistochemical biomarker status and pathological complete response (pCR) status. Histopathological sections (H&E staining) were analyzed to assess histopathological ECV by digital image analysis. Pearson’s correlation analysis was used to correlate between DECT-derived ECV and histopathological ECV fractions.Results: This study included 271 patients, with 314 breast lesions (61 benign and 253 malignant). The ECV fraction and ADC value showed comparable area under the curve (AUC) for distinguishing benign from malignant lesions (0.777 and 0.822, p = 0.123) and invasive carcinoma from DCIS (0.640 and 0.727, p = 0.115). There were significant differences in ECV fraction between different hormone receptor and Ki67 states (p = 0.001 ~ 0.014), while ADC values only differed among various Ki67 states (p < 0.001). The ECV fraction was lower (p = 0.007), while the ADC value was higher (p = 0.013) in the pCR than in the non-pCR group, with an AUC value of 0.748 and 0.730 (p = 0.887), respectively. There was a positive correlation between DECT-derived ECV and histopathological ECV fractions (r = 0.615, p < 0.01).Conclusions: Routine chest DECT-derived ECV fraction is a viable quantitative imaging biomarker for the characterization of breast tumor.

This paper examines the current situation of the development of the stall economy by analyzing data from Yujincheng area of Xi’an. And analyzes the four dimensions of the development of the stall economy in the context of COVID-19 under the SWOT perspective, and proposes feasible suggestions and countermeasures for the sustainable development of the stall economy by applying the four SWOT strategies.

Magnesium sulfate is the anticonvulsant of choice for eclampsia prophylaxis and treatment; however, the recommended dosing regimens are costly and cumbersome and can be administered only by skilled health professionals. The objectives of this study were to develop a robust exposure‐response model for the relationship between serum magnesium exposure and eclampsia using data from large studies of women with preeclampsia who received magnesium sulfate, and to predict eclampsia probabilities for standard and alternative (shorter treatment duration and/or fewer intramuscular injections) regimens. Exposure‐response modeling and simulation were applied to existing data. A total of 10 280 women with preeclampsia who received magnesium sulfate or placebo were evaluated. An existing population pharmacokinetic model was used to estimate individual serum magnesium exposure. Logistic regression was applied to quantify the serum magnesium area under the curve‐eclampsia rate relationship. Our exposure‐response model‐estimated eclampsia rates were comparable to observed rates. Several alternative regimens predicted magnesium peak concentration

To describe the phase 1 and population pharmacokinetic investigations that support dosing recommendations for elbasvir/grazoprevir (EBR/GZR) in hepatitis C virus-infected people with advanced chronic kidney disease. This was an open-label, two-part, multiple-dose trial (MK-5172 PN050; NCT01937975) in 24 non–HCV-infected participants with end-stage renal disease (ESRD) or severe renal impairment who received once-daily EBR 50 mg and GZR 100 mg for 10 days. Population pharmacokinetic analyses from the phase 3 C-SURFER study (PN052, NCT02092350) were also conducted. When comparing haemodialysis (HD) and non-HD days in participants with ESRD, geometric mean ratios (GMRs) (90% confidence intervals [CIs]) for EBR and GZR AUC0–24 were 1.14 (1.08–1.21) and 0.97 (0.87–1.09). When comparing ESRD and healthy participants, GMRs (90% CIs) for EBR and GZR AUC0–24 were 0.99 (0.75–1.30) and 0.83 (0.56–1.22) on HD days, and 0.86 (0.65–1.14) and 0.85 (0.58–1.25) on non-HD days. GMRs (90% CIs) for AUC0–24 in participants with severe renal impairment relative to healthy controls were 1.65 (1.09–2.49) for GZR and 1.86 (1.38–2.51) for EBR. In population modelling of data from C-SURFER, absolute geometric means of steady-state EBR AUC0–24 were 2.78 and 3.07 μM*h (HD and non-HD recipients) and GZR AUC0–24 were 1.80 and 2.34 μM*h (HD and non-HD recipients). EBR/GZR represents an important treatment option for HCV infection in people with severe renal impairment and those with ESRD. No dosage adjustment of EBR/GZR is required in people with any degree of renal impairment, including those receiving dialysis.

Industrial amino acid production strains of Corynebacterium glutamicum are usually obtained by mutagenesis. However, the genetic and metabolic characteristics and the efficient synthesis mechanism of the selected mutants are unclear. The aims of this study were (1) to determine the gene transcriptional patterns and intracellular metabolite levels of an L-leucine-producing mutant C. glutamicum CP and an L-valine-producing mutant C. glutamicum XV referring to wild type, and (2) to understand the efficient synthesis mechanism of target product of these mutants. For this purpose, transcriptomic and metabolomics analyses were combined to investigate the association between intracellular patterns and product synthesis. The high intracellular level of glucose and the low intracellular level of metabolites in the central carbon metabolism meant the glucose metabolism rate of two mutants was lower than wild type. However, the increased intracellular pentose level and gene transcription in the pentose phosphate pathway (PPP) indicated that the PPP of mutants was more active. Furthermore, the mutants showed higher intracellular level of NADPH, which was mainly generated in PPP. In the specific pathway for the synthesis of L-leucine and L-valine, the transcriptional level of most genes was upregulated in the mutants. However, the transcription of transaminase C coding gene Cgl2844 was downregulated in CP but upregulated in XV. The upregulation of Cgl2844 might benefit to the synthesis of L-valine and cause the significant decrease of intracellular level of L-alanine and L-glutamate of XV. These characteristics of the mutants provided insight into changes that could be made to systematically optimize the metabolic pathways for the production of L-leucine and L-valine.

Acetic acid, an important by-product of L-tryptophan production by Escherichia coli, is detrimental to cell growth and tryptophan accumulation. To reduce acetic acid accumulation and further improve the production of L-tryptophan, an acetyl-coenzyme A (acetyl-CoA) synthase (ACS) with high synthetic activity is needed. In this study, E. coli ACS was found to have a superior catalytic capability compared to that of other bacterial strains. To reduce the accumulation of acetic acid by metabolic overflow, a higher expression level of ACS was obtained by promoter engineering and copy number optimisation. Furthermore, reconstruction of the tri-carboxylic acid cycle (TCA) not only enhanced the supply of phosphoenolpyruvate (PEP), which is one of the precursors required for tryptophan synthesis, but also improved bacterial growth. The final engineered strain T16 accumulated 54.6 g/L of L-tryptophan, 11.4% more than the original strain T03, with an accumulation of only 1.4 g/L acetic acid after fermentation, which reduced by 74.5% compared to T03.

Corynebacterium glutamicum is an excellent platform for the production of amino acids, and is widely used in the fermentation industry. Most industrial strains are traditionally obtained by repeated processes of random mutation and selection, but the genotype of these strains is often unclear owing to the absence of genomic information. As such, it is difficult to improve the growth and amino acid production of these strains via metabolic engineering. In this study, we generated a complete genome map of an industrial L-valine-producing strain, C. glutamicum XV. In order to establish the relationship between genotypes and physiological characteristics, a comparative genomic analysis was performed to explore the core genome, structural variations, and gene mutations referring to an industrial L-leucine-producing strain, C. glutamicum CP, and the widely used C. glutamicum ATCC 13032. The results indicate that a 36,349 bp repeat sequence in the CP genome contained an additional copy each of lrp and brnFE genes, which benefited the export of L-leucine. However, in XV, the kgd and panB genes were disrupted by nucleotide insertion, which increase the availability of precursors to synthesize L-valine. Moreover, the specific amino acid substitutions in key enzymes increased their activities. Additionally, a novel strategy is proposed to remodel central carbon metabolism and reduce pyruvate consumption without having a negative impact on cell growth by introducing the CP-derived mutant H+/citrate symporter. These results further our understanding regarding the metabolic networks in these strains and help to elucidate the influence of different genotypes on these processes.

Magnesium sulfate is the standard therapy for prevention and treatment of eclampsia. Two standard dosing regimens require either continuous intravenous infusion or frequent, large‐volume intramuscular injections, which may preclude patients from receiving optimal care. This project sought to identify alternative, potentially more convenient, but similarly effective dosing regimens that could be used in restrictive clinical settings. A 2‐compartment population pharmacokinetic (PK) model was developed to characterize serial PK data from 92 pregnant women with preeclampsia who received magnesium sulfate. Body weight and serum creatinine concentration had a significant impact on magnesium PK. The final PK model was used to simulate magnesium concentration profiles for the 2 standard regimens and several simplified alternative dosing regimens. The simulations suggest that intravenous regimens with loading doses of 8 g over 60 minutes followed by 2 g/h for 10 hours and 12 g over 120 minutes followed by 2 g/h for 8 hours (same total dose as the standard intravenous regimen but shorter treatment duration) would result in magnesium concentrations below the toxic range. For the intramuscular regimens, higher maintenance doses given less frequently (4 g intravenously + 10‐g intramuscular loading doses with maintenance doses of 8 g every 6 hours or 10 g every 8 hours for 24 hours) or removal of the intravenous loading dose (eg, 10 g intramusculary every 8 hours for 24 hours) may be reasonable alternatives. In addition, individualized dose adjustments based on body weight and serum creatinine were proposed for the standard regimens.

The replacement of promoters with various strengths is an effective strategy to fine-tune gene expression. More available promoters with a broad range of transcription efficiency are needed in metabolic engineering. In this study, a putative protein coding gene CP_2454 was identified with a stable and high transcriptional level from an l-leucine-producing strain Corynebacterium glutamicum CP, which was absent in wild-type C. glutamicum ATCC 13032. The transcriptional level of CP_2454 was about 80.0% those of tuf and sod, and was 1.6 and 3.2 times those of ilvB and gapA, respectively. These promoters were cloned into C. glutamicum ATCC 13032 to control the expression of green fluorescent protein (GFP). While, the expressional level of GFP under the control of PCP_2454 was close to that of Ptuf and Psod, which was significantly higher than that of other tested promoters. The native promoter of ilvB controlling the expression of a feedback-resistant acetolactate synthase was replaced by PCP_2454, resulting in an increase of l-valine titer by 58.5%. A further 24.9% increase of l-valine titer was achieved after replacement of the promoter of ilvD encoding dihydroxyacid dehydratase with PCP_2454. Identification of the constitutive promoter PCP_2454 expands the promoter library of C. glutamicum and provides essential reference for tunable expression of target genes in C. glutamicum.

BACKGROUND Current intramuscular magnesium dosing regimens in low and middle-income countries are based on indirect absorption parameters to inform pharmacokinetic and pharmacodynamic response. OBJECTIVE To determine if therapeutic serum magnesium levels are obtained in women with severe preeclampsia receiving intramuscular administration of magnesium sulfate using the Pritchard regimen and to compare the key pharmacokinetic variables to those previously published. STUDY DESIGN Serum magnesium levels were obtained at multiple time points at baseline and after magnesium sulfate administration from women with severe preeclampsia receiving the standard Pritchard regimen for seizure prophylaxis at Bayero University, Kano, Nigeria. The pharmacokinetic profiles were constructed for the study cohort and the updated pharmacokinetic model was compared with the one that was previously published. RESULTS A total of 80 blood samples were collected from 20 women with severe preeclampsia (45 collected before childbirth and 35 collected after childbirth). After 11.5 hours of magnesium sulfate administration, 63% of women in the cohort had serum magnesium levels of ≥2.0 mmol/L. Data from women receiving the Pritchard regimen combined with data from women previously modeled after the receipt of intravenous magnesium sulfate were adequately described using a 2-compartment model with first-order absorption and linear elimination from the central compartment. All structural pharmacokinetic parameters including clearance, central volume of distribution, peripheral volume of distribution, and intercompartment clearance were adjusted for maternal weight, and the clearance was further adjusted for serum creatinine level and antepartum or postpartum status. The simulated pharmacokinetic profiles of the updated pharmacokinetic model and the previously published pharmacokinetic model are similar. In previously published pharmacokinetic modeling, absorption rate constant=0.32 and absolute bioavailability=0.86. In the updated pharmacokinetic model, absorption rate constant=0.45 and absolute bioavailability=0.91. CONCLUSION These data support the use of the Pritchard regimen as acceptable to achieve therapeutic serum magnesium levels and support the reported simulation of serum magnesium levels and eclampsia response associated with different intramuscular regimens.

The combination of the hepatitis C virus (HCV) nonstructural protein 5A (NS5A) inhibitor elbasvir and the NS3/4A protease inhibitor grazoprevir is a potent, once-daily therapy indicated for the treatment of chronic HCV infection in individuals coinfected with human immunodeficiency virus (HIV). We explored the pharmacokinetic interactions of elbasvir and grazoprevir with ritonavir and ritonavir-boosted HIV protease inhibitors in three phase 1 trials. Drug-drug interaction trials with healthy participants were conducted to evaluate the effect of ritonavir on the pharmacokinetics of grazoprevir (n = 10) and the potential two-way pharmacokinetic interactions of elbasvir (n = 30) or grazoprevir (n = 39) when coadministered with ritonavir-boosted atazanavir, lopinavir, or darunavir. Coadministration of ritonavir with grazoprevir increased grazoprevir exposure; the geometric mean ratio (GMR) for grazoprevir plus ritonavir versus grazoprevir alone area under the concentration-time curve from 0 to 24 h (AUC0-24) was 1.91 (90% confidence interval [CI]; 1.31 to 2.79). Grazoprevir exposure was markedly increased with coadministration of atazanavir-ritonavir, lopinavir-ritonavir, and darunavir-ritonavir, with GMRs for grazoprevir AUC0-24 of 10.58 (90% CI, 7.78 to 14.39), 12.86 (90% CI, 10.25 to 16.13), and 7.50 (90% CI, 5.92 to 9.51), respectively. Elbasvir exposure was increased with coadministration of atazanavir-ritonavir, lopinavir-ritonavir, and darunavir-ritonavir, with GMRs for elbasvir AUC0-24 of 4.76 (90% CI, 4.07 to 5.56), 3.71 (90% CI, 3.05 to 4.53), and 1.66 (90% CI, 1.35 to 2.05), respectively. Grazoprevir and elbasvir had little effect on atazanavir, lopinavir, and darunavir pharmacokinetics. Coadministration of elbasvir-grazoprevir with atazanavir-ritonavir, lopinavir-ritonavir, or darunavir-ritonavir is contraindicated, owing to an increase in grazoprevir exposure. Therefore, HIV treatment regimens without HIV protease inhibitors should be considered for HCV/HIV-coinfected individuals who are being treated with elbasvir-grazoprevir. ispartof: ANTIMICROBIAL AGENTS AND CHEMOTHERAPY vol:63 issue:4 ispartof: location:United States status: published

Tryptophan, an aromatic amino acid, has been widely used in food industry because it participates in the regulation of protein synthesis and metabolic network in vivo. In this study, we obtained a strain named TRP03 by enhancing the tryptophan synthesis pathway, which could accumulate tryptophan at approximately 35 g/L in a 5 L bioreactor. We then modified the central metabolic pathway of TRP03, to increase the supply of the precursor phosphoenolpyruvate (PEP), the genes related to PEP were modified. Furthermore, citric acid transport system and TCA were upregulated to effectively increase cell growth. We observed that strain TRP07 that could accumulate tryptophan at approximately 49 g/L with a yield of 0.186 g tryptophan/g glucose in a 5 L bioreactor. By-products such as glutamate and acetic acid were reduced to 0.8 g/L and 2.2 g/L, respectively.

Additional file 1. Primers used in this study.

Near-infrared spectroscopy has manifested its merits and great potentials in various areas. In the modern fermentation industries, near-infrared spectroscopy technique has been utilized for monitoring the quality of raw materials and products, and controlling the whole fermentation process. In this study, near-infrared spectroscopy was used to monitor the leucine fermentation by Corynebacterium glutamicum. A model for the prediction of leucine concentration was established, which had a R2 of 0.9905. The prediction values calculated using this model well fitted the true values, which suggested that the method could accurately predict and monitor the fermentation process.

In this paper, a study to enhance the filtration for solid/liquid materials difficult to be filtered, such as highly viscous, highly compactible or gel like materials, is presented. Filter aids diatomaceous earth and wood pulp cellulose are used to enhance the filtration by improving filter cake structure and properties in the filtration of a biological health product and a highly viscous chemical fiber polymer melt product. The property of solid/liquid systems, filtration at different flow rates, specific cake resistance, cake wetness, filtration rate, filtrate turbidity for filter aid selection and evaluation, and operation optimization are investigated. The results are successfully applied to industrial process, and can be used as a reference for similar filtration applications.

Telcagepant (MK-0974) is a novel oral calcitonin gene-related peptide (CGRP) receptor antagonist and is currently under clinical development. Results from phases II and III clinical trials have suggested that telcagepant is effective for migraine treatment. A reliable and high throughput protein precipitation (PPT) method for determination of telcagepant in human plasma using liquid chromatography coupled with atmospheric pressure chemical ionization (APCI) tandem mass spectrometry has been developed. Clinical samples, internal standard (IS) and acetonitrile are transferred into 96-well plates using a robotic liquid handling system. An aliquot of 10 microL supernatant is directly injected into the LC-MS/MS system where separation is performed on a FluoPhase RP (150 x 2.1mm, 5 microm) column with an isocratic mobile phase (60% acetonitrile with 0.1% formic acid and 40% water with 0.1% formic acid) at 0.2 mL/min. The interfering 3S-diastereomer of telcagepant, which is observed in clinical samples, is chromatographically resolved from telcagepant. The PPT procedure significantly reduces the time required for sample processing and the assay is sufficiently sensitive for detection using both API 4000 and API 3000 mass spectrometers. The linear calibration range is 5-5000 nM using 200 microL of plasma. Assay intraday validation was conducted using six calibration curves derived from six lots of human control plasma. Calibration standard accuracy did not deviate by more than 3% and 6% of nominal values, and precision did not exceed 4% coefficient of variation (CV) and 10% CV, respectively on the API 4000 and API 3000. Several clinical phases IIb and III studies have been successfully supported with this assay.

A previously proposed partition equilibrium model for quantitative prediction of analyte response in electrospray ionization mass spectrometry is modified to yield an improved linear relationship. Analyte mass spectrometer response is modeled by a competition mechanism between analyte and background electrolytes that is based on partition equilibrium considerations. The correlation between analyte response and solution composition is described by the linear model over a wide concentration range and the improved model is shown to be valid for a wide range of experimental conditions. The behavior of an analyte in a salt solution, which could not be explained by the original model, is correctly predicted. The ion suppression effects of 16:0 lysophosphatidylcholine (LPC) on analyte signals are attributed to a combination of competition for excess charge and reduction of total charge due to surface tension effects. In contrast to the complicated mathematical forms that comprise the original model, the simplified model described here can more easily be employed to predict analyte mass spectrometer responses for solutions containing multiple components.