Risk Factors for Infectious Complications following Endoscopic Retrograde Cholangiopancreatography in Liver Transplant Patients: A Single-Center Study.

Background: Liver transplant recipients often require endoscopic retrograde cholangiopancreatography (ERCP) for biliary complications, which can lead to infections. This retrospective single-center study aimed to identify risk factors for infectious complications following ERCP in liver transplant patients. Methods: A retrospective analysis was conducted on 285 elective ERCP interventions performed in 88 liver transplant patients at a tertiary care center. The primary endpoint was the occurrence of an infection following ERCP. Univariable and multivariable regression analyses, Cox regression, and log-rank tests were employed to assess the influence of various factors on the incidence of infectious complications. Results: Among the 285 ERCP interventions, isolated anastomotic stenosis was found in 175 cases, ischemic type biliary lesion (ITBL) in 103 cases, and choledocholithiasis in seven cases. Bile duct interventions were performed in 96.9% of all ERCPs. Infections after ERCP occurred in 46 cases (16.1%). Independent risk factors for infection included male sex (OR 24.19), prednisolone therapy (OR 4.5), ITBL (OR 4.51), sphincterotomy (OR 2.44), cholangioscopy (OR 3.22), dilatation therapy of the bile ducts (OR 9.48), and delayed prophylactic antibiotic therapy (>1 h after ERCP) (OR 2.93). Additionally, infections following previous ERCP interventions were associated with an increased incidence of infections following future ERCP interventions (p < 0.0001). Conclusion: In liver transplant patients undergoing ERCP, male sex, prednisolone therapy, and complex bile duct interventions independently raised infection risks. Delayed antibiotic treatment further increased this risk. Patients with ITBL were notably susceptible due to incomplete drainage. Additionally, a history of post-ERCP infections signaled higher future risks, necessitating close monitoring and timely antibiotic prophylaxis.

Validation of a size exclusion method for concomitant purification and formulation of peptide radiopharmaceuticals.

BACKGROUND: Both in clinical routine and in preclinical research, the established standard procedure for the final purification of radiometal-labeled peptide radiopharmaceuticals is cartridge-based reversed-phase (RP) solid phase extraction (SPE). It allows the rapid and quantitative separation of the radiolabeled peptide from hydrophilic impurities and easy integration into automated synthesis procedures. However, product elution from RP cartridges necessitates the use of organic solvents and product recovery is sometimes limited. Thus, an alternative purification method based on commercially available size exclusion cartridges was investigated. RESULTS: Since most peptide radiopharmaceuticals have a molecular weight > 1 kDa, Sephadex G10 cartridges with a molecular size cut-off of 700 Da were used for the final purification of a broad palette of 68Ga-, 64Cu- and 99mTc-labeled experimental peptide radiotracers as well as the clinically relevant ligand PSMA-617. Results (radiochemical purity (RCP, determined by ITLC), recovery from the solid support) were compared to the respective standard RP-SPE method. Generally, retention of unreacted 68Ga, 64Cu and 99mTc salts on the G10 cartridges was quantitative up to the specified elution volume (1.2 mL) for 68Ga and 99mTc and 99.6% for 64Cu. Even at increased elution volumes of 1.5-2 mL, RCPs of the eluted 68Ga- and 99mTc -radiopeptides were > 99%. For all peptides with a molecular weight ≥ 2 kDa, product recovery from the G10 cartridges was consistently > 85% upon respective adjustment of the elution volume. Product recovery was lowest for [68Ga]Ga-PSMA-617 (67%, 1.2 mL to 84%, 2 mL). The pH of the final product solution was found to be volume-dependent (1.2 mL: pH 6.3; 1.5 mL: pH 5.9; 2 mL: pH 5.5). Notably, the G10 cartridges were reused up to 20 times without compromising performance, and implementation of the method in an automated radiosynthesis procedure was successful. CONCLUSIONS: Overall, size exclusion purification yielded all peptide radiopharmaceuticals in excellent radiochemical purities (> 99%) in saline within 10-12 min. Although product recovery is marginally inferior to classical SPE purifications, this method has the advantage of completely avoiding organic solvents and representing a cost-effective, easy-to-implement purification approach for automated radiotracer synthesis.

Functional and Morphological Outcomes after Trabeculectomy and Deep Sclerectomy-Results from a Monocentric Registry Study.

The aim of this study was to compare the effectiveness of trabeculectomy (TE) and deep sclerectomy (DS) in lowering intraocular pressure (IOP) and thereby preserving visual field and peripapillary retinal nerve fiber layer (RNFL) tissue in primary open-angle glaucoma (POAG) cases. IOP, number of IOP-lowering medications, visual acuity, mean defect of standard automated perimetry, and mean peripapillary RNFL thickness were retrospectively collected and followed up for 3 years after surgery. TE was performed in 104 eyes and DS in 183 eyes. Age, gender, laterality, IOP, number of medications, visual acuity, perimetry mean defect, and peripapillary RNFL thickness were equally distributed at baseline. Mean IOP decreased from 23.8 ± 1.4 mmHg and 23.1 ± 0.4 mmHg to 13.4 ± 0.6 mmHg (p < 0.001) and 15.4 ± 0.7 mmHg (p = 0.001) in the TE and DS groups, respectively. Mean defect remained stable (TE: -11.5 ± 0.9 dB to -12.0 ± 1.1 (p = 0.090); DS: -10.5 ± 0.9 dB to -11.0 ± 1.0 dB (p = 0.302)), while mean peripapillary RNFL thickness showed further deterioration during follow-up (TE group: 64.4 ± 2.1 µm to 59.7 ± 3.5 µm (p < 0.001); DS group: 64.9 ± 1.9 µm to 58.4 ± 2.1 µm (p < 0.001)). Both TE and DS were comparably effective concerning postoperative reduction in IOP and medication. However, glaucoma disease further progressed during follow-up.

Profiling the dysregulated immune response in sepsis: overcoming challenges to achieve the goal of precision medicine.

Sepsis is characterised by a dysregulated host immune response to infection. Despite recognition of its significance, immune status monitoring is not implemented in clinical practice due in part to the current absence of direct therapeutic implications. Technological advances in immunological profiling could enhance our understanding of immune dysregulation and facilitate integration into clinical practice. In this Review, we provide an overview of the current state of immune profiling in sepsis, including its use, current challenges, and opportunities for progress. We highlight the important role of immunological biomarkers in facilitating predictive enrichment in current and future treatment scenarios. We propose that multiple immune and non-immune-related parameters, including clinical and microbiological data, be integrated into diagnostic and predictive combitypes, with the aid of machine learning and artificial intelligence techniques. These combitypes could form the basis of workable algorithms to guide clinical decisions that make precision medicine in sepsis a reality and improve patient outcomes.

Association of Asymmetric and Symmetric Dimethylarginine with Inflammation in the Population-Based Study of Health in Pomerania.

The amino acids arginine (Arg), asymmetric (ADMA) and symmetric dimethylarginine (SDMA) are related to nitric oxide (NO) metabolism and potential markers of two different disease entities: cardiovascular disease such as atherosclerosis and systemic inflammation in critically ill patients with sepsis. Although very different in their pathophysiological genesis, both entities involve the functional integrity of blood vessels. In this context, large population-based data associating NO metabolites with proinflammatory markers, e.g., white blood cell count (WBC), high-sensitivity C-reactive protein (hsCRP), and fibrinogen, or cytokines are sparse. We investigated the association of Arg, ADMA and SDMA with WBC, hsCRP, and fibrinogen in 3556 participants of the Study of Health in Pomerania (SHIP)-TREND study. Furthermore, in a subcohort of 456 subjects, 31 inflammatory markers and cytokines were analyzed. We identified Arg and SDMA to be positively associated with hsCRP (ß coefficient 0.010, standard error (SE) 0.002 and 0.298, 0.137, respectively) as well as fibrinogen (ß 5.23 × 10-3, SE 4.75 × 10-4 and 0.083, 0.031, respectively). ADMA was not associated with WBC, hsCRP, or fibrinogen. Furthermore, in the subcohort, Arg was inversely related to a proliferation-inducing ligand (APRIL). SDMA was positively associated with osteocalcin, tumor necrosis factor receptor 1 and 2, and soluble cluster of differentiation 30. Our findings provide new insights into the involvement of Arg, ADMA, and SDMA in subclinical inflammation in the general population.

Pesticides in rice-based products commercialised in Argentina.

People with coeliac disease have a limited diet. Therefore, rice-based products are an ideal alternative. Highlighting this import item, an analytical methodology was validated to determine pesticides in rice-based product samples. The precision was satisfactory for all pesticides since the RSD did not exceed 13% in any case. Regarding recovery, the method had values close to 100%. The limit of quantification was established at 10 µg/kg and the expanded uncertainty was less than 20%. After validation, 80 samples of toasts and rice crackers were analysed. All samples were compliant with the national regulations for dichlorvos and tebuconazole. The pesticide that was present in the highest number of samples was pirimiphos - methyl, but all below the maximum residue limit. From all samples analysed, 38 were positive for at least one pesticide and only one contained four pesticides simultaneously: deltamethrin, pirimiphos-methyl, kresoxim-methyl and epoxiconazole.

Oxidative damage associated with exposure to heavy metals present in topsoils in central Chile.

Exposure to heavy metals may cause the overproduction of reactive oxygen species, generating oxidative stress and consequently, various harms to human health. The soil surrounding the Ventanas Industrial Complex, in Puchuncaví and Quintero municipal districts on the central Chilean coast, contains heavy metal concentrations (As, Cu, Pb, Zn, among others) that far exceed the maximum permissible levels established by Italian soil standards (used as a reference). This study aimed to investigate the potential association between heavy metal exposure in humans and the levels of oxidative stress biomarkers in inhabitants of these locations. We took blood samples from 140 adults living in sites with high concentrations of heavy metals in the soil and compared them with blood samples from 140 adults living in areas with normal heavy metal concentrations. We assessed lipid peroxidation, damage to genetic material, and Total Antioxidant Capacity in these blood samples. Our results indicate an association between oxidative damage and heavy metal exposure, where the inhabitants living in exposed areas have a higher level of DNA damage compared with those living in control areas. Given that DNA damage is one of the main factors in carcinogenesis, these results are of interest, both for public health and for public policies aimed at limiting human exposure to environmental pollution.

Tunable Synthetic Hydrogels to Study Angiogenic Sprouting.

Angiogenic sprouting, the formation of new blood vessels from pre-existing vasculature, is tightly regulated by the properties of the surrounding tissue microenvironment. Although the extracellular matrix has been shown to be a major regulator of this process, it is not clear how individual biochemical and mechanical properties influence endothelial cell sprouting. This information gap is largely due to the lack of suitable in vitro models that recapitulate angiogenic sprouting in a 3D environment with independent control over matrix properties. Here, we present protocols for the preparation of endothelial cell spheroid-laden synthetic, dextran-based hydrogels, which serve as a highly tunable 3D scaffold. The adjustment of the hydrogels' adhesiveness, stiffness, and degradability is demonstrated in detail. Finally, we describe assays to elucidate how individual matrix properties regulate angiogenic sprouting, including their analysis by immunofluorescence staining and imaging. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Synthesis of methacrylated dextran (DexMA) Basic Protocol 2: Generation of endothelial cell spheroids in microwells Basic Protocol 3: Endothelial cell sprouting in hydrogels of tunable stiffness Basic Protocol 4: Endothelial cell sprouting in hydrogels of tunable adhesiveness Basic Protocol 5: Endothelial cell sprouting in hydrogels of tunable degradability Basic Protocol 6: Imaging of endothelial cell spheroid-laden hydrogels Support Protocol 1: Preparation of pro-angiogenic cocktail for endothelial cell sprouting.

Modulation of the activation of endothelial nitric oxide synthase and nitrosative stress biomarkers by aspirin triggered lipoxins: A possible mechanism of action of aspirin in the antiphospholipid syndrome.

PROBLEM: Antiphospholipid syndrome (APS) is characterized by the clinical manifestation of vascular thrombosis (VT) or pregnancy morbidity (PM) and antiphospholipid antibodies (aPL) that can modify the nitric oxide production. Low-dose aspirin is used in the prevention and treatment of diverse alterations of pregnancy. One of the mechanisms of action of aspirin is to induce the production of aspirin-triggered-lipoxins (ATL). The aim of this study was to evaluate the modulatory effect of ATL over the activation of endothelial nitric oxide synthase (eNOS) and nitrosative stress biomarkers induced by aPL. METHODS: We used polyclonal IgG and sera from women with aPL and PM/VT or VT only, and from women with PM only and positive for non-criteria aPL (SN-OAPS). In these sera, biomarkers of nitrosative stress (nitrites and nitrotyrosine) were measured. The protein expression of nitrotyrosine and the phosphorylation of eNOS (at Ser1177) were estimated in human umbilical vein endothelial cells (HUVECs) stimulated with polyclonal IgG with or without ATL. RESULTS: Women with SN-OAPS showed increased circulating levels of nitrites and nitrotyrosine. Likewise, polyclonal IgG from either SN-OAPS or VT patients stimulated nitrotyrosine expression in HUVECs. ATL decreased the nitrotyrosine expression induced by polyclonal IgG from the SN-OAPS group. ATL also recovered the reduced eNOS phosphorylation at Ser1177 in HUVECs stimulated with polyclonal IgG from women with PM/VT or SN-OAPS. CONCLUSIONS: Increased nitrosative stress present in serum of women with SN-OAPS is associated with IgG-mediated impaired endothelial NO synthesis in endothelial cells. ATL prevent these cellular changes.

Potential Contribution of Ancient Introgression to the Evolution of a Derived Reproductive Strategy in Ricefishes.

Transitions from no parental care to extensive care are costly and involve major changes in life history, behavior, and morphology. Nevertheless, in Sulawesi ricefishes, pelvic brooding evolved from transfer brooding in two distantly related lineages within the genera Adrianichthys and Oryzias, respectively. Females of pelvic brooding species carry their eggs attached to their belly until the fry hatches. Despite their phylogenetic distance, both pelvic brooding lineages share a set of external morphological traits. A recent study found no direct gene flow between pelvic brooding lineages, suggesting independent evolution of the derived reproductive strategy. Convergent evolution can, however, also rely on repeated sorting of preexisting variation of an admixed ancestral population, especially when subjected to similar external selection pressures. We thus used a multispecies coalescent model and D-statistics to identify gene-tree-species-tree incongruencies, to evaluate the evolution of pelvic brooding with respect to interspecific gene flow not only between pelvic brooding lineages but also between pelvic brooding lineages and other Sulawesi ricefish lineages. We found a general network-like evolution in Sulawesi ricefishes, and as previously reported, we detected no gene flow between the pelvic brooding lineages. Instead, we found hybridization between the ancestor of pelvic brooding Oryzias and the common ancestor of the Oryzias species from the Lake Poso area. We further detected signs of introgression within the confidence interval of a quantitative trait locus associated with pelvic brooding in O. eversi. Our results hint toward a contribution of ancient standing genetic variation to the evolution of pelvic brooding in Oryzias.

Feto-placental Unit: From Development to Function.

The placenta is an intriguing organ that allows us to survive intrauterine life. This essential organ connects both mother and fetus and plays a crucial role in maternal and fetal well-being. This chapter presents an overview of the morphological and functional aspects of human placental development. First, we describe early human placental development and the characterization of the cell types found in the human placenta. Second, the human placenta from the second trimester to the term of gestation is reviewed, focusing on the morphology and specific pathologies that affect the placenta. Finally, we focus on the placenta's primary functions, such as oxygen and nutrient transport, and their importance for placental development.

The Placental Function Beyond Pregnancy: Insights from Latin America.

Currently, more than 100,000 papers had been published studying the placenta in both physiological and pathological contexts. However, relevant health conditions affecting placental function, mostly found in low-income countries, should be evaluated deeper. This review will raise some - of what we think necessary - points of discussion regarding challenging topics not fully understood, including the paternal versus maternal contribution on placental genes imprinting, placenta-brain communication, and some environmental conditions affecting the placenta. The discussions are parts of an international effort to fulfil some gaps observed in this area, and Latin-American research groups currently evaluate that.

Influence of corticosteroid treatment on CXCR4 expression in DLBCL.

BACKGROUND: CXCR4-targeted radioligand therapy (RLT) with [177Lu]Lu/[90Y]Y-PentixaTher has recently evolved as a promising therapeutic option for patients with advanced hematological cancers. Given their advanced disease stage, most patients scheduled for PentixaTher RLT require concomitant or bridging chemotherapy to prevent intermittent tumor progression. These (mostly combination) therapies may cause significant downregulation of tumoral CXCR4 expression, challenging the applicability of PentixaTher RLT. This study therefore aimed at investigating the influence of corticosteroids, a central component of these chemotherapies, on CXCR4 regulation in diffuse large B cell lymphoma (DLBCL). METHODS: Different DLBCL cell lines (Daudi, OCI-LY1, SUDHL-4, -5-, -6 and -8) as well as the human T-cell lymphoma cell line Jurkat were incubated with Dexamethasone (Dex; 0.5 and 5 µM, respectively) and Prednisolone (Pred; 5 and 50 µM, respectively) for different time points (2 h, 24 h). Treatment-induced modulation of cellular CXCR4 surface expression was assessed via flow cytometry (FC) and compared to untreated cells. A radioligand binding assay with [125I]CPCR4.3 was performed in parallel using the same cells. To quantify potential corticosteroid treatment effects on tumoral CXCR4 expression in vivo, OCI-LY1 bearing NSG mice were injected 50 µg Dex/mouse i.p. (daily for 6 days). Then, a biodistribution study (1 h p.i.) using [68Ga]PentixaTher was performed, and tracer biodistribution in treated (n = 5) vs untreated mice (n = 5) was compared. RESULTS: In the in vitro experiments, a strongly cell line-dependent upregulation of CXCR4 was observed for both Dex and Pred treatment, with negligible differences between the high and low dose. While in Jurkat, Daudi and SUDHL-8 cells, CXCR4 expression remained unchanged, a 1.5- to 3.5-fold increase in CXCR4 cell surface expression was observed for SUDHL-5 < SUDHL-4 /-6 < OCI-LY1 via FC compared to untreated cells. This increase in CXCR4 expression was also reflected in correspondingly enhanced [125I]CPCR4.3 accumulation in treated cells, with a linear correlation between FC and radioligand binding data. In vivo, Dex treatment led to a general increase of [68Ga]PentixaTher uptake in all organs compared to untreated animals, as a result of a higher tracer concentration in blood. However, we observed an overproportionally enhanced [68Ga]PentixaTher uptake in the OCI-LY1 tumors in treated (21.0 ± 5.5%iD/g) vs untreated (9.2 ± 2.8%iD/g) mice, resulting in higher tumor-to-background ratios in the treatment group. CONCLUSION: Overall, corticosteroid treatment (Dex/Pred) consistently induced an upregulation of CXCR4 expression DBLCL cells in vitro, albeit in a very cell line-dependent manner. For the cell line with the most pronounced Dex-induced CXCR4 upregulation, OCI-LY1, the in vitro findings were corroborated by an in vivo biodistribution study. This confirms that at least the corticosteroid component of stabilizing chemotherapy regimens in DLBCL patients prior to [177Lu]Lu-PentixaTher RLT does not lead to downregulation of the molecular target CXCR4 and may even have a beneficiary effect. However, further studies are needed to investigate if and to what extent the other commonly used chemotherapeutic agents affect CXCR4 expression on DLBCL to ensure the choice of an appropriate treatment regimen prior to [177Lu]Lu/[90Y]Y-PentixaTher RLT.

Comprehensive Characterization of Tissues Derived from Animals at Different Regenerative Stages: A Comparative Analysis between Fetal and Adult Mouse Skin.

Tissue regeneration capabilities vary significantly throughout an organism's lifespan. For example, mammals can fully regenerate until they reach specific developmental stages, after which they can only repair the tissue without restoring its original architecture and function. The high regenerative potential of fetal stages has been attributed to various factors, such as stem cells, the immune system, specific growth factors, and the presence of extracellular matrix molecules upon damage. To better understand the local differences between regenerative and reparative tissues, we conducted a comparative analysis of skin derived from mice at regenerative and reparative stages. Our findings show that both types of skin differ in their molecular composition, structure, and functionality. We observed a significant increase in cellular density, nucleic acid content, neutral lipid density, Collagen III, and glycosaminoglycans in regenerative skin compared with reparative skin. Additionally, regenerative skin had significantly higher porosity, metabolic activity, water absorption capacity, and elasticity than reparative skin. Finally, our results also revealed significant differences in lipid distribution, extracellular matrix pore size, and proteoglycans between the two groups. This study provides comprehensive data on the molecular and structural clues that enable full tissue regeneration in fetal stages, which could aid in developing new biomaterials and strategies for tissue engineering and regeneration.

Expression of Basement Membrane Molecules by Wharton Jelly Stem Cells (WJSC) in Full-Term Human Umbilical Cords, Cell Cultures and Microtissues.

Wharton's jelly stem cells (WJSC) from the human umbilical cord (UC) are one of the most promising mesenchymal stem cells (MSC) in tissue engineering (TE) and advanced therapies. The cell niche is a key element for both, MSC and fully differentiated tissues, to preserve their unique features. The basement membrane (BM) is an essential structure during embryonic development and in adult tissues. Epithelial BMs are well-known, but similar structures are present in other histological structures, such as in peripheral nerve fibers, myocytes or chondrocytes. Previous studies suggest the expression of some BM molecules within the Wharton's Jelly (WJ) of UC, but the distribution pattern and full expression profile of these molecules have not been yet elucidated. In this sense, the aim of this histological study was to evaluate the expression of main BM molecules within the WJ, cultured WJSC and during WJSC microtissue (WJSC-MT) formation process. Results confirmed the presence of a pericellular matrix composed by the main BM molecules-collagens (IV, VII), HSPG2, agrin, laminin and nidogen-around the WJSC within UC. Additionally, ex vivo studies demonstrated the synthesis of these BM molecules, except agrin, especially during WJSC-MT formation process. The WJSC capability to synthesize main BM molecules could offer new alternatives for the generation of biomimetic-engineered substitutes where these molecules are particularly needed.

Intrasexual cuticular hydrocarbon dimorphism in a wasp sheds light on hydrocarbon biosynthesis genes in Hymenoptera.

Cuticular hydrocarbons (CHCs) cover the cuticle of insects and serve as desiccation barrier and as semiochemicals. While the main enzymatic steps of CHC biosynthesis are well understood, few of the underlying genes have been identified. Here we show how exploitation of intrasexual CHC dimorphism in a mason wasp, Odynerus spinipes, in combination with whole-genome sequencing and comparative transcriptomics facilitated identification of such genes. RNAi-mediated knockdown of twelve candidate gene orthologs in the honey bee, Apis mellifera, confirmed nine genes impacting CHC profile composition. Most of them have predicted functions consistent with current knowledge of CHC metabolism. However, we found first-time evidence for a fatty acid amide hydrolase also influencing CHC profile composition. In situ hybridization experiments furthermore suggest trophocytes participating in CHC biosynthesis. Our results set the base for experimental CHC profile manipulation in Hymenoptera and imply that the evolutionary origin of CHC biosynthesis predates the arthropods' colonization of land.

Solvent Dynamics of Aqueous Halides before and after Photoionization.

Electron transfer reactions can be strongly influenced by solvent dynamics. We study the photoionization of halides in water as a model system for such reactions. There are no internal nuclear degrees of freedom in the solute, allowing the dynamics of the solvent to be uniquely identified. We simulate the equilibrium solvent dynamics for Cl-, Br-, I-, and their respective neutral atoms in water, comparing quantum mechanical/molecular mechanical (QM/MM) and classical molecular dynamics (MD) methods. On the basis of the obtained configurations, we calculate the extended X-ray absorption fine structure (EXAFS) spectra rigorously based on the MD snapshots and compare them in detail with other theoretical and experimental results available in the literature. We find our EXAFS spectra based on QM/MM MD simulations in good agreement with their experimental counterparts for the ions. Classical MD simulations for the ions lead to EXAFS spectra that agree equally well with the experiment when it comes to the oscillatory period of the signal, even though they differ from the QM/MM radial distribution functions extracted from the MD. The amplitude is, however, considerably overestimated. This suggests that to judge the reliability of theoretical simulation methods or to elucidate fine details of the atomistic dynamics of the solvent based on EXAFS spectra, the amplitude as well as the oscillatory period need to be considered. If simulations fail qualitatively, as does the classical MD for the aqueous neutral halogen atoms, the resulting EXAFS will also be strongly affected in both oscillatory period and amplitude. The good reliability of QM/MM-based EXAFS simulations, together with clear qualitative differences in the EXAFS spectra found between halides and their atomic counterparts, suggests that a combined theory and experimental EXAFS approach is suitable for elucidating the nonequilibrium solvent dynamics in the photoionization of halides and possibly also for electron transfer reactions in more complex systems.