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1.
J Biol Chem ; 300(5): 107243, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38556086

RESUMEN

Sterols are ubiquitous membrane constituents that persist to a large extent in the environment due to their water insolubility and chemical inertness. Recently, an oxygenase-independent sterol degradation pathway was discovered in a cholesterol-grown denitrifying bacterium Sterolibacterium (S.) denitrificans. It achieves hydroxylation of the unactivated primary C26 of the isoprenoid side chain to an allylic alcohol via a phosphorylated intermediate in a four-step ATP-dependent enzyme cascade. However, this pathway is incompatible with the degradation of widely distributed steroids containing a double bond at C22 in the isoprenoid side chain such as the plant sterol stigmasterol. Here, we have enriched a prototypical delta-24 desaturase from S. denitrificans, which catalyzes the electron acceptor-dependent oxidation of the intermediate stigmast-1,4-diene-3-one to a conjugated (22,24)-diene. We suggest an α4ß4 architecture of the 440 kDa enzyme, with each subunit covalently binding an flavin mononucleotide cofactor to a histidyl residue. As isolated, both flavins are present as red semiquinone radicals, which can be reduced by stigmast-1,4-diene-3-one but cannot be oxidized even with strong oxidizing agents. We propose a mechanism involving an allylic radical intermediate in which two flavin semiquinones each abstract one hydrogen atom from the substrate. The conjugated delta-22,24 moiety formed allows for the subsequent hydroxylation of the terminal C26 with water by a heterologously produced molybdenum-dependent steroid C26 dehydrogenase 2. In conclusion, the pathway elucidated for delta-22 steroids achieves oxygen-independent hydroxylation of the isoprenoid side chain by bypassing the ATP-dependent formation of a phosphorylated intermediate.


Asunto(s)
Proteínas Bacterianas , Betaproteobacteria , Ácido Graso Desaturasas , Estigmasterol , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Molibdeno/química , Estigmasterol/metabolismo , Betaproteobacteria/enzimología , Ácido Graso Desaturasas/genética , Ácido Graso Desaturasas/metabolismo , Hidroxilación/genética , Flavinas/metabolismo
2.
Chembiochem ; : e202400258, 2024 Jun 18.
Artículo en Inglés | MEDLINE | ID: mdl-38887142

RESUMEN

S-adenosyl-l-methionine-dependent methyltransferases (MTs) are involved in the C-methylation of a variety of natural products. The MTs SgvM from Streptomyces griseoviridis and MrsA from Pseudomonas syringae pv. syringae catalyze the methylation of the ß-carbon atom of α-keto acids in the biosynthesis of the antibiotic natural products viridogrisein and 3-methylarginine, respectively. MrsA shows high substrate selectivity for 5-guanidino-2-oxovalerate, while other α-keto acids, such as the SgvM substrates 4-methyl-2-oxovalerate, 2-oxovalerate, and phenylpyruvate, are not accepted. Here we report the crystal structures of SgvM and MrsA in the apo form and bound with substrate or S-adenosyl-l-methionine. By investigating key residues for substrate recognition in the active sites of both enzymes and engineering MrsA by site-directed mutagenesis, the substrate range of MrsA was extended to accept α-keto acid substrates of SgvM with uncharged and lipophilic ß-residues. Our results showcase the transfer of the substrate scope of α-keto acid MTs from different biosynthetic pathways by rational design.

3.
Drug Metab Dispos ; 2024 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-38408868

RESUMEN

Fluorination of organic compounds plays an important role in the chemical and pharmaceutical industry and is often applied in order to improve physicochemical parameters or modify pharmacological properties. While oxidative and reductive defluorination have been shown to be responsible for the metabolic degradation of organofluorine compounds, the involvement of hydrolytic mechanisms catalyzed by human enzymes has not been reported so far. Here, we investigated the enzymatic defluorination of terminally monofluorinated aliphates with [1-(5-fluoropentyl)-1H-indol-3-yl]-1-naphthalenyl-methanone (AM-2201) as a model substance. We performed in vitro biotransformation using pooled human liver microsomes (pHLM) and human recombinant cytochrome P450 (CYP) assays. In order to elucidate the underlying mechanisms, modified incubation conditions were applied including the use of deuterium labeled AM-2201 (d2 -AM-2201). Identification of the main metabolites and analysis of their isotopic composition was performed by liquid-chromatography coupled to time-of-flight-mass-spectrometry (LC-QToF-MS). Quantification of the metabolites was achieved with a validated method based on liquid-chromatography-tandem-mass-spectrometry (LC-MS/MS). CYP 1A2 mediated defluorination of d2 -AM-2201 revealed an isotopic pattern of the defluorinated 5-hydroxypentyl metabolite (5-HPM) indicating a redox mechanism with an aldehyde as a plausible intermediate. In contrast, formation of 5-HPM by pHLM was observed independently of the presence of atmospheric oxygen or co-factors regenerating the redox system. pHLM incubation of d2 -AM-2201 confirmed the hypothesis of a non-oxidative mechanism involved in the defluorination of the 5-fluoropentyl moiety. So far, enzymatically catalyzed, hydrolytic defluorination was only described in bacteria and other prokaryotes. The presented data prove the involvement of a hydrolytic mechanism catalyzed by human microsomal enzymes other than CYP. Significance Statement Elucidating the mechanisms involved in the enzymatic detoxification of organofluorine compounds is crucial for enhancing our understanding and facilitating the design and development of drugs with improved pharmacokinetic profiles. The carbon-fluorine bond possesses a high binding energy, which suggests that non-activated fluoroalkanes would not undergo hydrolytic cleavage. However, our study provides evidence for the involvement of a non-oxidative mechanism catalyzed by human liver enzymes. It is important to consider CYP-independent, hydrolytic defluorination, when investigating the pharmacokinetic properties of fluorinated xenobiotics.

4.
Opt Express ; 32(10): 17424-17432, 2024 May 06.
Artículo en Inglés | MEDLINE | ID: mdl-38858926

RESUMEN

Resonant enhancement inside an optical cavity has been a wide-spread approach to increase efficiency of nonlinear optical conversion processes while reducing the demands on the driving laser power. This concept has been particularly important for high harmonic generation XUV sources, where passive femtosecond enhancement cavities allowed significant increase in repetition rates required for applications in photoelectron spectroscopy, XUV frequency comb spectroscopy, including the recent endeavor of thorium nuclear clock development. In addition to passive cavities, it has been shown that comparable driving conditions can be achieved inside mode-locked thin-disk laser oscillators, offering a simplified single-stage alternative. This approach is less sensitive to losses thanks to the presence of gain inside the cavity and should thus allow higher conversion efficiencies through tolerating higher intensity in the gas target. Here, we show that the intra-oscillator approach can indeed surpass the much more mature technology of passive enhancement cavities in terms of XUV flux, even reaching comparable values to single-pass sources based on chirped-pulse fiber amplifier lasers. Our system operates at 17 MHz repetition rate generating photon energies between 60 eV and 100 eV. Importantly, this covers the highly attractive wavelength for the silicon industry of 13.5 nm at which our source delivers 60 nW of outcoupled average power per harmonic order.

5.
Respir Res ; 25(1): 69, 2024 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-38317197

RESUMEN

BACKGROUND: Although multidrug-resistant bacteria (MDR) are common in patients undergoing prolonged weaning, there is little data on their impact on weaning and patient outcomes. METHODS: This is a retrospective analysis of consecutive patients who underwent prolonged weaning and were at a university weaning centre from January 2018 to December 2020. The influence of MDR colonisation and infection on weaning success (category 3a and 3b), successful prolonged weaning from invasive mechanical ventilation (IMV) with or without the need for non-invasive ventilation (NIV) compared with category 3c (weaning failure 3cI or death 3cII) was investigated. The pathogen groups considered were: multidrug-resistant gram-negative bacteria (MDRGN), methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus spp. (VRE). RESULTS: A total of 206 patients were studied, of whom 91 (44.2%) showed evidence of MDR bacteria (32% VRE, 1.5% MRSA and 16% MDRGN), with 25 patients also meeting the criteria for MDR infection. 70.9% of the 206 patients were successfully weaned from IMV, 8.7% died. In 72.2% of cases, nosocomial pneumonia and other infections were the main cause of death. Patients with evidence of MDR (infection and colonisation) had a higher incidence of weaning failure than those without evidence of MDR (48% vs. 34.8% vs. 21.7%). In multivariate analyses, MDR infection (OR 4.9, p = 0.004) was an independent risk factor for weaning failure, along with male sex (OR 2.3, p = 0.025), Charlson Comorbidity Index (OR 1.2, p = 0.027), pH (OR 2.7, p < 0.001) and duration of IMV before admission (OR 1.01, p < 0.001). In addition, MDR infection was the only independent risk factor for death (category 3cII), (OR 6.66, p = 0.007). CONCLUSION: Patients with MDR infection are significantly more likely to die during the weaning process. There is an urgent need to develop non-antibiotic approaches for the prevention and treatment of MDR infections as well as clinical research on antibiotic stewardship in prolonged weaning as well as in ICUs.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Respiración Artificial , Humanos , Masculino , Respiración Artificial/efectos adversos , Estudios Retrospectivos , Desconexión del Ventilador , Bacterias , Antibacterianos/uso terapéutico
6.
Respir Res ; 25(1): 60, 2024 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-38281006

RESUMEN

BACKGROUND: Long-term invasive mechanical ventilation (IMV) is a major burden for those affected and causes high costs for the health care system. Early risk assessment is a prerequisite for the best possible support of high-risk patients during the weaning process. We aimed to identify risk factors for long-term IMV within 96 h (h) after the onset of IMV. METHODS: The analysis was based on data from one of Germany's largest statutory health insurance funds; patients who received IMV ≥ 96 h and were admitted in January 2015 at the earliest and discharged in December 2017 at the latest were analysed. OPS and ICD codes of IMV patients were considered, including the 365 days before intubation and 30 days after discharge. Long-term IMV was defined as evidence of invasive home mechanical ventilation (HMV), IMV ≥ 500 h, or readmission with (re)prolonged ventilation. RESULTS: In the analysis of 7758 hospitalisations, criteria for long-term IMV were met in 38.3% of cases, of which 13.9% had evidence of HMV, 73.1% received IMV ≥ 500 h and/or 40.3% were re-hospitalised with IMV. Several independent risk factors were identified (p < 0.005 each), including pre-diagnoses such as pneumothorax (OR 2.10), acute pancreatitis (OR 2.64), eating disorders (OR 1.99) or rheumatic mitral valve disease (OR 1.89). Among ICU admissions, previous dependence on an aspirator or respirator (OR 5.13), and previous tracheostomy (OR 2.17) were particularly important, while neurosurgery (OR 2.61), early tracheostomy (OR 3.97) and treatment for severe respiratory failure such as positioning treatment (OR 2.31) and extracorporeal lung support (OR 1.80) were relevant procedures in the first 96 h after intubation. CONCLUSION: This comprehensive analysis of health claims has identified several risk factors for the risk of long-term ventilation. In addition to the known clinical risks, the information obtained may help to identify patients at risk at an early stage. Trial registration The PRiVENT study was retrospectively registered at ClinicalTrials.gov (NCT05260853). Registered at March 2, 2022.


Asunto(s)
Ventilación no Invasiva , Pancreatitis , Humanos , Respiración Artificial/efectos adversos , Respiración Artificial/métodos , Estudios Longitudinales , Enfermedad Aguda , Factores de Riesgo
7.
Phys Chem Chem Phys ; 26(15): 11988-12002, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38573315

RESUMEN

Ionic liquid crystals (ILCs) combine the ion mobility of ionic liquids with the order and self-assembly of thermotropic mesophases. To understand the role of the anion in ILCs, wedge-shaped arylguanidinium salts with tetradecyloxy side chains were chosen as benchmark systems and their liquid crystalline self-assembly in the bulk phase as well as their electrochemical behavior in solution were studied depending on the anion. Differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (WAXS, SAXS) experiments revealed that for spherical anions, the phase width of the hexagonal columnar mesophase increased with the anion size, while for non-spherical anions, the trends were less clear cut. Depending on the anion, the ILCs showed different stability towards electrochemical oxidation and reduction with the most stable being the PF6 based compound. Cyclic voltammetry (CV) and density functional theory (DFT) calculations suggest a possible contribution of the guanidinium cation to the oxidation processes.

8.
Nutr Neurosci ; : 1-14, 2024 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-38170169

RESUMEN

Over recent decades, dietary patterns have changed significantly due to the increasing availability of convenient, ultra-processed refined foods. Refined foods are commonly depleted of key bioactive compounds, which have been associated with several deleterious health conditions. As the gut microbiome can influence the brain through a bidirectional communication system known as the 'microbiota-gut-brain axis', the consumption of refined foods has the potential to affect cognitive health. In this study, multi-omics approaches were employed to assess the effect of a refined diet on the microbiota-gut-brain axis, with a particular focus on bile acid metabolism. Mice maintained on a refined low-fat diet (rLFD), consisting of high sucrose, processed carbohydrates and low fibre content, for eight weeks displayed significant gut microbial dysbiosis, as indicated by diminished alpha diversity metrics (p < 0.05) and altered beta diversity (p < 0.05) when compared to mice receiving a chow diet. Changes in gut microbiota composition paralleled modulation of the metabolome, including a significant reduction in short-chain fatty acids (acetate, propionate and n-butyrate; p < 0.001) and alterations in bile acid concentrations. Interestingly, the rLFD led to dysregulated bile acid concentrations across both the colon (p < 0.05) and the brain (p < 0.05) which coincided with altered neuroinflammatory gene expression. In particular, the concentration of TCA, TDCA and T-α-MCA was inversely correlated with the expression of NF-κB1, a key transcription factor in neuroinflammation. Overall, our results suggest a novel link between a refined low-fat diet and detrimental neuronal processes, likely in part through modulation of the microbiota-gut-brain axis and bile acid dysmetabolism.

9.
Appl Microbiol Biotechnol ; 108(1): 250, 2024 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-38430417

RESUMEN

The fungal diglycosidase α-rhamnosyl-ß-glucosidase I (αRßG I) from Acremonium sp. DSM 24697 catalyzes the glycosylation of various OH-acceptors using the citrus flavanone hesperidin. We successfully applied a one-pot biocatalysis process to synthesize 4-methylumbellipheryl rutinoside (4-MUR) and glyceryl rutinoside using a citrus peel residue as sugar donor. This residue, which contained 3.5 % [w/w] hesperidin, is the remaining of citrus processing after producing orange juice, essential oil, and peel-juice. The low-cost compound glycerol was utilized in the synthesis of glyceryl rutinoside. We implemented a simple method for the obtention of glyceryl rutinoside with 99 % yield, and its purification involving activated charcoal, which also facilitated the recovery of the by-product hesperetin through liquid-liquid extraction. This process presents a promising alternative for biorefinery operations, highlighting the valuable role of αRßG I in valorizing glycerol and agricultural by-products. KEYPOINTS: • αRßG I catalyzed the synthesis of rutinosides using a suspension of OPW as sugar donor. • The glycosylation of aliphatic polyalcohols by the αRßG I resulted in products bearing a single rutinose moiety. • αRßG I catalyzed the synthesis of glyceryl rutinoside with high glycosylation/hydrolysis selectivity (99 % yield).


Asunto(s)
Acremonium , Hesperidina , Hesperidina/química , Glicerol
10.
BMC Geriatr ; 24(1): 461, 2024 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-38797837

RESUMEN

BACKGROUND: Fragility fractures of the pelvis (FFPs) represent a significant health burden, particularly for the elderly. The role of sarcopenia, an age-related loss of muscle mass and function, in the development and impact of these fractures is not well understood. This study aims to investigate the prevalence and impact of osteoporosis and sarcopenia in patients presenting with FFPs. METHODS: This retrospective study evaluated 140 elderly patients with FFPs. The diagnosis of sarcopenia was assessed by psoas muscle area (PMA) and the height-adjusted psoas muscle index (PMI) measured on computed tomography (CT) scans. Clinical data, radiological findings and functional outcomes were recorded and compared with the presence or absence of sarcopenia and osteoporosis. RESULTS: Our study cohort comprised 119 female (85.0%) and 21 (15.0%) male patients. The mean age at the time of injury or onset of symptoms was 82.26 ± 8.50 years. Sarcopenia was diagnosed in 68.6% (n = 96) patients using PMA and 68.8% (n = 88) using PMI. 73.6% (n = 103) of our study population had osteoporosis and 20.0% (n = 28) presented with osteopenia. Patients with sarcopenia and osteoporosis had longer hospital stays (p < 0.04), a higher rate of complications (p < 0.048) and functional recovery was significantly impaired, as evidenced by a greater need for assistance in daily living (p < 0.03). However, they were less likely to undergo surgery (p < 0.03) and the type of FFP differed significantly (p < 0.04). There was no significant difference in mortality rate, pre-hospital health status, age or gender. CONCLUSION: Our study highlights the important role of sarcopenia in FFPs in terms of the serious impact on health and quality of life in elderly patients especially when osteoporosis and sarcopenia occur together. Identifying and targeting sarcopenia in older patients may be an important strategy to reduce pelvic fractures and improve recovery. Further research is needed to develop effective prevention and treatment approaches that target muscle health in the elderly.


Asunto(s)
Sarcopenia , Humanos , Sarcopenia/epidemiología , Masculino , Femenino , Estudios Retrospectivos , Anciano de 80 o más Años , Anciano , Factores de Riesgo , Huesos Pélvicos/lesiones , Huesos Pélvicos/diagnóstico por imagen , Osteoporosis/epidemiología , Osteoporosis/complicaciones , Músculos Psoas/diagnóstico por imagen , Fracturas Osteoporóticas/epidemiología , Tomografía Computarizada por Rayos X/métodos , Prevalencia , Fracturas Óseas/epidemiología , Fracturas Óseas/complicaciones
11.
BMC Med Educ ; 24(1): 420, 2024 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-38641835

RESUMEN

BACKGROUND: PRiVENT (PRevention of invasive VENTilation) is an evaluation of a bundle of interventions aimed at the prevention of long-term invasive mechanical ventilation. One of these elements is an e-learning course for healthcare professionals to improve weaning expertise. The aim of our analysis is to examine the implementation of the course in cooperating intensive care units. METHODS: The course has been developed through a peer review process by pulmonary and critical care physicians in collaboration with respiratory therapists, supported by health services researchers and a professional e-learning agency. The e-learning platform "weLearn" was made available online to participating healthcare professionals. Feedback on the e-learning programme was obtained and discussed in quality circles (QCs). We measured the acceptance and use of the programme through access statistics. RESULTS: The e-learning course "Joint Prevention of Long-Term Ventilation" consists of 7 separate modules with practice-oriented training units as well as a cross-module area and corresponding interactive case studies. Users can receive 23 CME (continuing medical education) credits. The platform was released on July 1, 2021. By June 28, 2023, 214 users from 33 clinics had registered. Most users (77-98%) completed the modules, thus performing well in the test, where 90-100% passed. In the QCs, the users commended the structure and practical relevance of the programme, as well as the opportunity to earn CME credits. CONCLUSION: Especially for medical staff in intensive care units, where continuous training is often a challenge during shift work, e-learning is a useful supplement to existing medical training. TRIAL REGISTRATION: The PRiVENT study is registered at ClinicalTrials.gov (NCT05260853) on 02/03/2022.


Asunto(s)
Instrucción por Computador , Humanos , Desconexión del Ventilador , Aprendizaje , Personal de Salud/educación , Cuidados Críticos
12.
Angew Chem Int Ed Engl ; : e202403535, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38951114

RESUMEN

Many bacterial natural products contain C-branched sugars, including components from the outer cell wall or antibiotically active metabolites. The enzymatic C-branching of keto sugars leading to longer side chains (≥C2), is catalyzed by thiamine diphosphate (ThDP)-dependent enzymes. Chiral tertiary α-hydroxy ketones are formed in this process. The ThDP enzymes that catalyze C-branching reactions belong to one of three enzymatic superfamilies: decarboxy-lases, transketolases, and α-ketoacid dehydrogenases 2, but branching of keto sugars has only been demonstrated for decarboxylases. In this study, we showed that an α-ketoacid dehydrogenase is responsible for C-branching of the deoxyketo sugar amycolose in the biosynthesis of kibdelomycin in Kibdelosporangium sp. MA7385. In addition, we characterized an amino transferase in the same biosynthetic gene cluster (BGC) that accepts a sterically demanding tertiary α-hydroxy ketone in a downstream reaction. Subsequently, we identified approximately 400 similar BGCs in silico, suggesting that there is a large diversity of possible ThDP-dependent enzymes catalyzing the C-branching of keto sugars and subsequent modifications.

13.
Angew Chem Int Ed Engl ; 63(34): e202404045, 2024 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-38874074

RESUMEN

The thiamine diphosphate (ThDP)-binding motif, characterized by the canonical GDG(X)24-27N sequence, is highly conserved among ThDP-dependent enzymes. We investigated a ThDP-dependent lyase (JanthE from Janthinobacterium sp. HH01) with an unusual cysteine (C458) replacing the first glycine of this motif. JanthE exhibits a high substrate promiscuity and accepts long aliphatic α-keto acids as donors. Sterically hindered aromatic aldehydes or non-activated ketones are acceptor substrates, giving access to a variety of secondary and tertiary alcohols as carboligation products. The crystal structure solved at a resolution of 1.9 Šreveals that C458 is not primarily involved in cofactor binding as previously thought for the canonical glycine. Instead, it coordinates methionine 406, thus ensuring the integrity of the active site and the enzyme activity. In addition, we have determined the long-sought genuine tetrahedral intermediates formed with pyruvate and 2-oxobutyrate in the pre-decarboxylation states and deciphered the atomic details for their stabilization in the active site. Collectively, we unravel an unexpected role for the first residue of the ThDP-binding motif and unlock a family of lyases that can perform valuable carboligation reactions.


Asunto(s)
Tiamina Pirofosfato , Tiamina Pirofosfato/metabolismo , Tiamina Pirofosfato/química , Liasas/metabolismo , Liasas/química , Secuencias de Aminoácidos , Dominio Catalítico , Cristalografía por Rayos X , Especificidad por Sustrato , Modelos Moleculares
14.
Angew Chem Int Ed Engl ; : e202407425, 2024 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-38963262

RESUMEN

Bioactive dimeric (pre-)anthraquinones are ubiquitous in nature. Their biosynthesis via an oxidative phenol coupling (OPC) step is catalyzed by either cytochrome P450 enzymes, peroxidases, or laccases. While the biocatalysis of OPC in molds (Ascomycota) is well-known, the respective enzymes of mushroom-forming fungi (Basidiomycota) are still unknown. Here, we report on the biosynthesis of the atropisomers phlegmacin A1 and B1, unsymmetrical 7,10'-homo-coupled dihydroanthracenones of the mushroom Cortinarius odorifer. The biosynthesis was heterologously reconstituted in the mold Aspergillus niger. We show that methylation of the dimeric (pre-)anthraquinone building block atrochrysone to its 6-O-methyl ether torosachrysone by the O-methyltransferase (CoOMT1) precedes the regioselective homo-coupling to phlegmacin, catalyzed by an unspecific peroxygenase (CoUPO1). Our results revealed an unprecedented UPO-mediated unsymmetric OPC reaction, thereby expanding the biocatalytic portfolio of OPC-type reactions beyond the commonly reported enzymes. The findings highlight the pivotal role of OPC in natural processes, demonstrating that Basidiomycota employed peroxygenases to develop the ability to selectively couple aryls, distinct and convergent to any other group of organisms.

15.
Opt Express ; 31(26): 44823-44831, 2023 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-38178541

RESUMEN

A self-referenced optical frequency comb is presented based on Kerr-lens mode-locking of ytterbium-doped CALGO. The robust source delivers 3.5 W average power in 44 fs-long pulses at 1 GHz repetition rate. The residual root-mean-square timing jitter of the emitted pulse-train is 146 fs and the residual integrated phase noise of the carrier-envelope offset frequency is 107 mrad, both in a span from 1 Hz to 10 MHz. After stabilization, 2.7 W average power remains for direct application. This work represents the first multi-mode pumped Kerr-lens mode-locked optical frequency comb at gigahertz-level repetition rate.

16.
Org Lett ; 26(5): 1051-1055, 2024 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-38285916

RESUMEN

Two unprecedented fluorescent nucleosides that feature BN-doped polycyclic aromatic hydrocarbons are presented. One of them, having a BN-modified phenanthrene moiety incorporated, shows blue fluorescence but suffers from poor stability under aqueous conditions. The other nucleoside comprises an internally BN-doped pyrene as the chromophore. It shows green fluorescence in various solvents and is stable under aqueous and alkaline conditions.

17.
Curr Opin Chem Biol ; 82: 102510, 2024 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-39128325

RESUMEN

Mushroom-forming fungi exhibit a distinctive ecology, which is unsurprisingly also reflected in unique and divergent biosynthetic pathways. We review this phenomenon through the lens of the polyketide metabolism, where mushrooms often deviate from established principles and challenge conventional paradigms. This is evident not only by non-canonical enzyme architectures and functions but also by their propensity for multi-product synthases rather than single-product pathways. Nevertheless, mushrooms also feature many polyketides familiar from plants, bacteria, and fungi of their sister division Ascomycota, which, however, are the result of an independent evolution. In this regard, the captivating biosynthetic pathways of mushrooms might even help us understand the biological pressures that led to the simultaneous production of the same natural products (via convergent evolution, co-evolution, and/or metaevolution) and thus address the question of their raison d'être.

18.
J Pain Symptom Manage ; 67(4): 279-289.e6, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38154625

RESUMEN

CONTEXT: Leading oncology societies recommend monitoring symptoms and support needs through patient-reported outcome measures (PROMs), but their use for assessing specialist palliative care (SPC) need has not yet been explored. Research on SPC integration has focused on staff-assessed screening tools, which are time-consuming. OBJECTIVES: This study aimed to assess the diagnostic validity of the Integrated Palliative Outcome Scale (IPOS) and NCCN Distress Thermometer (NCCN DT) in identifying need for SPC in patients with incurable cancer. METHODS: In a cross-sectional study, patients with incurable cancer (prognosis <2 years) completed PROMs. In an independent process, the palliative care consultation service (PCCS) assessed the need for SPC in each patient through multiprofessional case review, and this was used as the reference standard. ROC analyses were employed to determine diagnostic validity. RESULTS: Of the 208 participants, 71 (34.1 %) were classified as having SPC need by the PCCS. Aiming for a minimum sensitivity of 80%, a cut-off of ≥2 items with high/very high burden in the IPOS resulted in a 90.2% sensitivity (specificity = 50; AUC = 0.791; CI 95%= 0.724-0.858). A cut-off of ≥5 resulted in a sensitivity of 80 % for NCCN DT (specificity = 49.5 %; AUC = 0.687; CI 95% = 0.596-0.777). CONCLUSION: PROMs are useful for identifying SPC need in cancer patients. Their implementation might facilitate timely integration of SPC. Future research should focus on an integrated assessment approach with PROMs that combines the requirements of the different specialties to save patient and staff resources.


Asunto(s)
Neoplasias , Cuidados Paliativos , Humanos , Cuidados Paliativos/métodos , Estudios Transversales , Neoplasias/diagnóstico , Neoplasias/terapia , Medición de Resultados Informados por el Paciente
19.
Brain Res ; : 149170, 2024 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-39163895

RESUMEN

Alzheimer's Disease (AD), responsible for 62% of all dementia cases, is a progressive neurodegenerative condition that leads to cognitive dysfunction. The prevalence of AD is consistently higher in women suggesting they are disproportionately affected by this disease. Despite this, our understanding of this female AD vulnerability remains limited. Menopause has been identified as a potential contributing factor to AD in women, with earlier menopause onset associated with greater AD risk. However, the underlying mechanisms responsible for this increased risk are not fully understood. This review examines the potential role of menopause in the development of Alzheimer's Disease providing a mechanistic overview of the available literature from hormones to pathology. While literature is now emerging that indicates a role of hormonal shifts, gut dysbiosis, lipid dysregulation and inflammation, more research is needed to fully elucidate the mechanisms involved.

20.
ASAIO J ; 70(8): 667-674, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38446867

RESUMEN

When determining extracorporeal oxygen transfer (V ML O 2 ) during venovenous extracorporeal membrane oxygenation (VV ECMO) dissolved oxygen is often considered to play a subordinate role due to its poor solubility in blood plasma. This study was designed to assess the impact of dissolved oxygen on systemic oxygenation in patients with acute respiratory distress syndrome (ARDS) on VV ECMO support by differentiating between dissolved and hemoglobin-bound extracorporeal oxygen transfer. We calculated both extracorporeal oxygen transfer based on blood gas analysis using the measuring energy expenditure in extracorporeal lung support patients (MEEP) protocol and measured oxygen uptake by the native lung with indirect calorimetry. Over 20% of V ML O 2 and over 10% of overall oxygen uptake (VO 2 total ) were realized as dissolved oxygen. The transfer of dissolved oxygen mainly depended on ECMO blood flow (BF ML ). In patients with severely impaired lung function dissolved oxygen accounted for up to 28% of VO 2 total . A clinically relevant amount of oxygen is transferred as physically dissolved fraction, which therefore needs to be considered when determining membrane lung function, manage ECMO settings or guiding the weaning procedure.


Asunto(s)
Oxigenación por Membrana Extracorpórea , Oxígeno , Síndrome de Dificultad Respiratoria , Oxigenación por Membrana Extracorpórea/métodos , Humanos , Oxígeno/sangre , Oxígeno/metabolismo , Síndrome de Dificultad Respiratoria/terapia , Persona de Mediana Edad , Masculino , Femenino , Adulto , Análisis de los Gases de la Sangre/métodos , Anciano , Consumo de Oxígeno/fisiología , Solubilidad
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