Enhancement of biohydrogen production rate in Rhodospirillum rubrum by a dynamic CO-feeding strategy using dark fermentation

Background Rhodospirillum rubrum is a purple non-sulphur bacterium that produces H2 by photofermentation of several organic compounds or by water gas-shift reaction during CO fermentation. Successful strategies for both processes have been developed in light-dependent systems. This work explores a dark fermentation bioprocess for H2 production from water using CO as the electron donor. Results The study of the influence of the stirring and the initial CO partial pressure (pCO) demonstrated that the process was inhibited at pCO of 1.00 atm. Optimal pCO value was established in 0.60 atm. CO dose adaptation to bacterial growth in fed-batch fermentations increased the global rate of H2 production, yielding 27.2 mmol H2 l−1 h−1 and reduced by 50% the operation time. A kinetic model was proposed to describe the evolution of the molecular species involved in gas and liquid phases in a wide range of pCO conditions from 0.10 to 1.00 atm. Conclusions Dark fermentation in R. rubrum expands the ways to produce biohydrogen from CO. This work optimizes this bioprocess at lab-bioreactor scale studying the influence of the stirring speed, the initial CO partial pressure and the operation in batch and fed-batch regimes. Dynamic CO supply adapted to the biomass growth enhances the productivity reached in darkness by other strategies described in the literature, being similar to that obtained under light continuous syngas fermentations. The kinetic model proposed describes all the conditions tested.

Pharmacokinetics of Non-β-Lactam β-Lactamase Inhibitors

The growing emergence of drug-resistant bacterial strains is an issue to treat severe infections, and many efforts have identified new pharmacological agents. The inhibitors of β-lactamases (BLI) have gained a prominent role in the safeguard of beta-lactams. In the last years, new β-lactam–BLI combinations have been registered or are still under clinical evaluation, demonstrating their effectiveness to treat complicated infections. It is also noteworthy that the pharmacokinetics of BLIs partly matches that of β-lactams companions, meaning that some clinical situations, as well as renal impairment and renal replacement therapies, may alter the disposition of both drugs. Common pharmacokinetic characteristics, linear pharmacokinetics across a wide range of doses, and known pharmacokinetic/pharmacodynamic parameters may guide modifications of dosing regimens for both β-lactams and BLIs. However, comorbidities (i.e., burns, diabetes, cancer) and severe changes in individual pathological conditions (i.e., acute renal impairment, sepsis) could make dose adaptation difficult, because the impact of those factors on BLI pharmacokinetics is partly known. Therapeutic drug monitoring protocols may overcome those issues and offer strategies to personalize drug doses in the intensive care setting. Further prospective clinical trials are warranted to improve the use of BLIs and their β-lactam companions in severe and complicated infections.

NRG-RTOG 1106/ACRIN 6697: A phase IIR trial of standard versus adaptive (mid-treatment PET-based) chemoradiotherapy for stage III NSCLC—Results and comparison to NRG-RTOG 0617 (non-personalized RT dose escalation).

8548 Background: NRG-RTOG 0617 (R0617) found that non-personalized dose escalation of radiotherapy (RT) with concurrent chemotherapy was deleterious. NRG-RTOG 1106/ACRIN 6697 (R1106) studied adaptive chemoradiotherapy, using tumor and patient individualized RT dose intensification simultaneously with field reduction, based upon mid-treatment FDG-PET. Methods: The control arms of both studies used 60 Gy (+ weekly carboplatin/paclitaxel). The investigational arm of R0617 used 74 Gy in 37 fractions, with no field/dose adaptation, while R1106 used mid-treatment FDG-PET (after ̃40 Gy) to design an individualized dose adaptive RT plan with daily-fraction size 2.2 to 3.8 Gy (up to 80.4 Gy/30 fractions), based upon a model of isotoxic lung risk. Nearly all (93%) patients had IMRT. No patients had consolidation immunotherapy. The primary endpoint for R1106 was local-regional-progression freedom (LRPF) assessed by central review. Other endpoints reported here were survival, toxicity, and institution-defined local/regional control. Results: From 2012-2017, 127 patients were enrolled to R1106 (43 in the standard and 84 in the adaptive arms), with a median follow-up of 3.6 years. The median actual RT dose in the adaptive arm was 71 Gy (Q1-Q3 68-76 Gy). The 2-year LRPF was 59.5% versus 54.6% (p=0.66) for standard versus adaptive RT; the 3-year survival rates were 49.1% versus 47.5% (p=0.80). An exploratory analysis of 2-year in-field local primary tumor control and local-regional tumor control (institution-assessed) were 58.5% and 55.6% for standard RT, and 75.6% and 66.3% for adaptive RT, respectively. As shown in the table, there were no significant differences in cardiac or esophageal adverse events between the two arms; the adaptive RT arm had more Grade 3+ respiratory events (23.8% versus 14.3%). Conclusions: NRG-RTOG1106 did not meet its primary endpoint of demonstrating improved LRPF. Unlike R0617, there was no suggestion of a detrimental effect of adaptive dose-intensified RT on survival and cardiac events. Studies to refine personalized RT, especially in the immunotherapy era, should be considered. Outcome comparison between R0617 and R1106. Clinical trial information: NCT01507428. [Table: see text]

Pre-therapeutic dihydropyridimidine dehydrogenase (DPD) deficiency screening: Impact on fluoropyrimidine dose reduction at the second chemotherapy cycle and on early severe toxicity.

3096 Background: DPD deficiency screening before fluoropyrimidine is a matter of debate. To avoid lethal toxicity, French authorities impose DPD screening before fluoropyrimidine-based chemotherapy by dosing uracilemia since April 2019. Methods: We have included all consecutive adult patients receiving 5-fluorouracil (5-FU) or capecitabin from April 2019 to January 2020 in 6 cancer centers. During the study period, different methods for screening had been applied: DPYD complete sequencing, phenotype (uracilemia and/or dihydrouracilemia/uracilemia ratio - UH2/U -) or both. All sceening tests were conducted in the same laboratory. Association between the method of DPD screening and fluoropyrimidine dose reduction at second chemotherapy cycle or on severe ≥grade 3 early toxicity (between first and second cycle) was evaluated using multivariate logistic regression. Concordance between genotype and phenotype for DPD deficiency was explored using Cohen Kappa test. Results: We included 597 patients, the median age was 63 (range, 55-77). The most prevalent cancers were digestive (68.3%), head and neck (19.4%) and breast (9.2%). 12.3% of patients received capecitabine and 87.3% received polychemotherapy. DPD deficiency screening was done for most of patients (n=519, 86.9%). DPD screening method consisted in full sequencing of DPYP (n=41; 7.9%), phenotype analysis (n=44, 8.5%) or both (n=424, 83.6%). We did not identify any complete DPD deficiency. Uracilemia was dosed for 467 patients, the median was 6.5 ng/mL and for 21 patients (4.5%) uracilemia was > 16 ng/mL and/or UH2/U <6, suggesting DPD deficiency. Severe early toxicities were observed for 82 patients (14%), with two patients presenting grade 5 toxicity. Overall DPD screening and method of DPD screening were not associated with fluoropyrimidine dose reduction at second cycle or early severe toxicity. In multivariate analysis, the only predictor for fluoropyrimidine reduction at second cycle (n = 125 patients) was polychemotherapy (OR=2.8; p=0.012). Kappa between uracilemia and UH2/U was 0.23 (poor concordance). Kappa between DPYP sequencing and uracilemia or UH2/U was 0.09 (very poor concordance). Conclusions: No DPD deficiency screening method was associated with dose adaptation at second cycle or early severe toxicity. The optimal strategy for DPD screening requires further clinical evaluation.

Advances and Perspectives in the Management of Varicella-Zoster Virus Infections

Varicella-zoster virus (VZV), a common and ubiquitous human-restricted pathogen, causes a primary infection (varicella or chickenpox) followed by establishment of latency in sensory ganglia. The virus can reactivate, causing herpes zoster (HZ, shingles) and leading to significant morbidity but rarely mortality, although in immunocompromised hosts, VZV can cause severe disseminated and occasionally fatal disease. We discuss VZV diseases and the decrease in their incidence due to the introduction of live-attenuated vaccines to prevent varicella or HZ. We also focus on acyclovir, valacyclovir, and famciclovir (FDA approved drugs to treat VZV infections), brivudine (used in some European countries) and amenamevir (a helicase-primase inhibitor, approved in Japan) that augur the beginning of a new era of anti-VZV therapy. Valnivudine hydrochloride (FV-100) and valomaciclovir stearate (in advanced stage of development) and several new molecules potentially good as anti-VZV candidates described during the last year are examined. We reflect on the role of antiviral agents in the treatment of VZV-associated diseases, as a large percentage of the at-risk population is not immunized, and on the limitations of currently FDA-approved anti-VZV drugs. Their low efficacy in controlling HZ pain and post-herpetic neuralgia development, and the need of multiple dosing regimens requiring daily dose adaptation for patients with renal failure urges the development of novel anti-VZV drugs.

Therapeutic Patient Education for Adrenal Insufficiency under COVID-19 Pandemic Conditions

Adrenal insufficiency (AI) requires life-long treatment with glucocorticoid replacement therapy. Over- or under-substitution carries the risk of increased morbidity in the form of side effects or adrenal crises. Glucocorticoid replacement therapy needs to be flexible with dose adaptation in special situations. This could not be managed by medical personnel on a daily basis, but requires an educated patient who has a good knowledge of the disease, understands his medical therapy and is able to perform situational dose adaptation. The rarity of the disease in combination with the need to respond to stressful situations with rapid glucocorticoid dose adjustment underlines that a well-trained patient is crucial for optimal management of the disease.In this literature review we provide background information further clarifying the need of education in patients with AI including the current shortcomings of medical therapy and of the treatment of patients with AI. We outline the aims of therapeutic patient education, present the concept of structured patient education in Germany, and discuss available results of patient group education programs. Furthermore, we propose strategies how therapeutic patient education for adrenal insufficiency can be organized under COVID-19 pandemic conditions.