Asymmetric Reduction of Prochiral Ketones by Using Self-Sufficient Heterogeneous Biocatalysts Based on NADPH-Dependent Ketoreductases.

The development of cell-free and self-sufficient biocatalytic systems represents an emerging approach to address more complex synthetic schemes under nonphysiological conditions. Herein, we report the development of a self-sufficient heterogeneous biocatalyst for the synthesis of chiral alcohols without the need to add an exogenous cofactor. In this work, an NADPH-dependent ketoreductase was primarily stabilized and further co-immobilized with NADPH to catalyze asymmetric reductions without the addition of an exogenous cofactor. As a result, the immobilized cofactor is accessible, and thus, it is recycled inside the porous structure without diffusing out into the bulk, as demonstrated by single-particle in operando studies. This self-sufficient heterogeneous biocatalyst was used and recycled for the asymmetric reduction of eleven carbonyl compounds in a batch reactor without the addition of exogenous NADPH to achieve the corresponding alcohols in 100 % yield and >99 % ee; this high performance was maintained over five consecutive reaction cycles. Likewise, the self-sufficient heterogeneous biocatalyst was integrated into a plug flow reactor for the continuous synthesis of one model secondary alcohol, which gave rise to a space-time yield of 97-112 g L-1 day-1 ; additionally, the immobilized cofactor accumulated a total turnover number of 1076 for 120 h. This is one of the few examples of the successful implementation of continuous reactions in aqueous media catalyzed by cell-free and immobilized systems that integrate both enzymes and cofactors into the solid phase.

Effect of Primary Care Center Characteristics, Healthcare Worker Vaccination Status and Patient Economic Setting on Patient Influenza Vaccination Coverage Rates.

BACKGROUND: Reaching the public health organizations targets of influenza vaccination in at-risk patient groups remains a challenge worldwide. Recognizing the relationship between the healthcare system characteristics and the economic environment of the population with vaccination uptake can be of great importance to improve. METHODS: Several characteristics were correlated in this retrospective ecological study with data from 6.8 million citizens, 15,812 healthcare workers across 258 primary care health centers, and average income by area of the care center in Spain. RESULTS: No correlation between HCW vaccination status and patient vaccination was found. A weak negative significant correlation between the size of the population the care center covers and their vaccination status did exist (6 mo.-59 yr., r = 0.19, p = 0.002; 60-64 yr., r = 0.23, p < 0.001; ≥65 yr., r = 0.23, p ≥ 0.001). The primary care centers with fewer HCWs had better uptake in the at-risk groups in the age groups of 60-64 yr. (r = 0.20, p = 0.002) and ≥65 (r = 0.023, p ≥ 0.001). A negative correlation was found regarding workload in the 6 mo.-59 yr. age group (r = 0.18, p = 0.004), which showed the at-risk groups that lived in the most economically deprived areas were more likely to be vaccinated. CONCLUSIONS: This study reveals that the confounding variables that determine influenza vaccination in a population and in HCWs are complex. Future influenza campaigns should address these especially considering the possibility of combining influenza and SARS-CoV-2 vaccines each year.

Tracing nanoparticles in vivo: a new general synthesis of positron emitting metal oxide nanoparticles by proton beam activation.

The synthesis of (18)F-labelled positron emitting NPs by direct irradiation of (18)O-enriched aluminum oxide NPs with 16 MeV protons is reported. Biodistribution studies of the labelled particles after intravenous administration were performed in male rats using positron emission tomography. The simple and general activation strategy can be applied to any in situ prepared core metal oxide particle for direct use or subsequent bio-compatible coating or encapsulation followed by functionalization.

Application of polymersomes engineered to target p32 protein for detection of small breast tumors in mice.

Triple negative breast cancer (TNBC) is the deadliest form of breast cancer and its successful treatment critically depends on early diagnosis and therapy. The multi-compartment protein p32 is overexpressed and present at cell surfaces in a variety of tumors, including TNBC, specifically in the malignant cells and endothelial cells, and in macrophages localized in hypoxic areas of the tumor. Herein we used polyethylene glycol-polycaprolactone polymersomes that were affinity targeted with the p32-binding tumor penetrating peptide LinTT1 (AKRGARSTA) for imaging of TNBC lesions. A tyrosine residue was added to the peptide to allow for 124I labeling and PET imaging. In a TNBC model in mice, systemic LinTT1-targeted polymersomes accumulated in early tumor lesions more than twice as efficiently as untargeted polymersomes with up to 20% ID/cc at 24 h after administration. The PET-imaging was very sensitive, allowing detection of tumors as small as ∼20 mm3. Confocal imaging of tumor tissue sections revealed a high degree of vascular exit and stromal penetration of LinTT1-targeted polymersomes and co-localization with tumor-associated macrophages. Our studies show that systemic LinTT1-targeted polymersomes can be potentially used for precision-guided tumor imaging and treatment of TNBC.

Imaging the role of toll-like receptor 4 on cell proliferation and inflammation after cerebral ischemia by positron emission tomography.

The influence of toll-like receptor 4 on neurogenesis and inflammation has been scarcely explored so far by using neuroimaging techniques. For this purpose, we performed magnetic resonance imaging and positron emission tomography with 3'-deoxy-3'-[(18)F]fluorothymidine and [(11)C]PK11195 at 2, 7, and 14 days following cerebral ischemia in TLR4(+/+)and TLR4(-/-)mice. MRI showed similar infarction volumes in both groups. Despite this, positron emission tomography with 3'-deoxy-3'-[(18)F]fluorothymidine and [(11)C]PK11195 evidenced an increase of neurogenesis and a decrease of inflammation in TLR4(-/-)mice after ischemia. These results evidence the versatility of neuroimaging techniques to monitor the role of toll-like receptor 4 after cerebral ischemia.

In vivo imaging of dopaminergic neurotransmission after transient focal ischemia in rats.

The precise biologic mechanisms involved in functional recovery processes in response to stroke such as dopaminergic neurotransmission are still largely unknown. For this purpose, we performed in parallel in vivo magnetic resonance imaging and positron emission tomography (PET) with [(18)F]fluorodeoxyglucose ([(18)F]FDG) and [(11)C]raclopride at 1, 3, 7, 14, 21, and 28 days after middle cerebral artery occlusion in rats. In the ischemic territory, PET [(18)F]FDG showed a initial decrease in cerebral metabolism followed by a time-dependent recovery to quasi-normal values at day 14 after ischemia. The PET with [(11)C]raclopride, a ligand for dopamine D(2) receptor, showed a sustained binding during the first week after ischemia that declined dramatically from day 14 to day 28. Interestingly, a slight increase in [(11)C]raclopride binding was observed at days 1 to 3 followed by the uppermost binding at day 7 in the contralateral territory. Likewise, in vitro autoradiography using [(3)H]raclopride confirmed these in vivo results. Finally, the neurologic test showed major neurologic impairment at day 1 followed by a recovery of the cerebral function at day 28 after cerebral ischemia. Taken together, these results might suggest that dopamine D(2) receptor changes in the contralateral hemisphere could have a key role in functional recovery after cerebral ischemia.

Biodistribution and metabolism of 11C-labeled Kendine 91 in mice and rats.

The biodistribution pattern of [(11)C]Kendine 91 (a novel HDAC inhibitor) after IV administration has been evaluated using Positron Emission Tomography (rats) and gamma counting of dissected tissues (rats and mice) at different doses (1 µg/kg and 10.0 mg/kg). Metabolism in mice plasma has been also investigated by radio-HPLC. Obtained results (fast accumulation in lungs, heart, kidneys and liver; lower uptake in pancreas and muscle) are in concordance with previously reported results using HPLC/MS-MS. Plasma analysis studies showed a fast metabolism of the radiotracer.