Predictors of Mortality and Orotracheal Intubation in Patients with Pulmonary Barotrauma Due to COVID-19: An Italian Multicenter Observational Study during Two Years of the Pandemic.

Introduction: Coronavirus disease 2019 (COVID-19) is a significant and novel cause of acute respiratory distress syndrome (ARDS). During the COVID-19 pandemic, there has been an increase in the incidence of cases involving pneumothorax and pneumomediastinum. However, the risk factors associated with poor outcomes in these patients remain unclear. Methods: This observational study collected clinical and imaging data from COVID-19 patients with PTX and/or PNM across five tertiary hospitals in central Italy between 1 March 2020 and 1 March 2022. This study also calculated the incidence of PTX and PNM and utilized multivariable regression analysis and Kaplan-Meier curve analysis to identify predictor factors for 28-day mortality and 3-day orotracheal intubation after PTX/PNM. This study also considered the impact of the three main variants of concern (VoCs) (alfa, delta, and omicron) circulating during the study period. Results: During the study period, a total of 11,938 patients with COVID-19 were admitted. This study found several factors independently associated with a higher risk of death in COVID-19 patients within 28 days of pulmonary barotrauma. These factors included a SOFA score ≥ 4 (OR 3.22, p = 0.013), vasopressor/inotropic therapy (OR 11.8, p < 0.001), hypercapnia (OR 2.72, p = 0.021), PaO2/FiO2 ratio < 150 mmHg (OR 10.9, p < 0.001), and cardiovascular diseases (OR 7.9, p < 0.001). This study also found that a SOFA score ≥ 4 (OR 3.10, p = 0.015), PCO2 > 45 mmHg (OR 6.0, p = 0.003), and P/F ratio < 150 mmHg (OR 2.9, p < 0.042) were factors independently associated with a higher risk of orotracheal intubation (OTI) within 3 days from PTX/PNM in patients with non-invasive mechanical ventilation. SARS-CoV-2 VoCs were not associated with 28-day mortality or the risk of OTI. The estimated cumulative probability of OTI in patients after pneumothorax was 44.0% on the first day, 67.8% on the second day, and 68.9% on the third day, according to univariable survival analysis. In patients who had pneumomediastinum only, the estimated cumulative probability of OTI was 37.5%, 46.7%, and 57.7% on the first, second, and third days, respectively. The overall incidence of PTX/PNM among hospitalized COVID-19 patients was 1.42%, which increased up to 4.1% in patients receiving invasive mechanical ventilation. Conclusions: This study suggests that a high SOFA score (≥4), the need for vasopressor/inotropic therapy, hypercapnia, and PaO2/FiO2 ratio < 150 mmHg in COVID-19 patients with pulmonary barotrauma are associated with higher rates of intubation, ICU admission, and mortality. Identifying these risk factors early on can help healthcare providers anticipate and manage these patients more effectively and provide timely interventions with appropriate intensive care, ultimately improving their outcomes.

Physico-Chemical Investigation and Antimicrobial Efficacy of Ozonated Oils: The Case Study of Commercial Ozonated Olive and Sunflower Seed Refined Oils.

Drug resistance represents one of the great plagues of our time worldwide. This largely limits the treatment of common infections and requires the development of new antibiotics or other alternative approaches. Noteworthy, the indiscriminate use of antibiotics is mostly responsible for the selection of mutations that confer drug resistance to microbes. In this regard, recently, ozone has been raising interest for its unique biological properties when dissolved in natural oils. Ozonated oils have been reported to act in a non-specific way on microorganisms hindering the acquisition of advantageous mutations that result in resistance. Here, we focused on the antimicrobial effect of two commercial olive (OOO) and sunflower seeds (OSO) oils. Nuclear magnetic resonance spectroscopy and thermal analysis showed the change in the chemical composition of the oils after ozonation treatment. Different ozonated oil concentrations were then used to evaluate their antimicrobial profile against Candida albicans, Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli by agar diffusion and broth dilution methods. Cytotoxicity was also evaluated in keratinocytes and epithelial cells. Overall, our results revealed that both OOO and OSO showed a potent microbicidal effect, especially against C. albicans (IC50 = OOO: 0.3 mg/mL and OSO: 0.2 mg/mL) and E. faecalis (IC50 = OOO: 0.4 mg/mL and OSO: 2.8 mg/mL) albeit exerting a certain effect also against S. aureus and E. coli. Moreover, both OOO and OSO do not yield any relevant cytotoxic effect at the active concentrations in both cell lines. This indicates that the ozonated oils studied are not toxic for mammalian cells despite exerting a potent antimicrobial effect on specific microorganisms. Therefore, OOO and OSO may be considered to integrate standard therapies in the treatment of common infections, likely overcoming drug resistance issues.

Benzothiazole DNA gyrase inhibitors and their conjugates with siderophore mimics: design, synthesis and evaluation.

Benzothiazole-based bacterial DNA gyrase and topoisomerase IV inhibitors are promising new antibacterial agents with potent activity against Gram-positive and Gram-negative bacterial strains. The aim of this study was to improve the uptake of these inhibitors into the cytoplasm of Gram-negative bacteria by conjugating them to the small siderophore mimics. The best conjugate 18b displayed potent Escherichia coli DNA gyrase and topoisomerase IV inhibition. The interaction analysis of molecular dynamics simulation trajectory showed the important contribution of the siderophore mimic moiety to binding affinity. By NMR spectroscopy, we demonstrated that the hydroxypyridinone moiety alone was responsible for the chelation of iron(iii). Moreover, 18b showed an enhancement of antibacterial activity against E. coli JW5503 in an iron-depleted medium, clearly indicating an increased uptake of 18b in this bacterial strain.

The combination of inorganic phosphate and pyrophosphate 31 P-NMR for the electrodeless pH determination in the 5-12 range.

Potentiometry is the primary pH measurement method, but alternatives are sought beyond glass electrodes operative limitations. In nuclear magnetic resonance (NMR) experiments, electrodeless pH sensing is important to track changes along titrations, during chemical reactions or inside compartmentalized environments inaccessible to electrodes, for instance. Although several interesting NMR pH indicators have been already presented, the potential of inorganic phosphate is overlooked, despite its common presence in NMR samples as the buffer main component. Its use for electrodeless pH determination can be expanded by exploiting all its three proton dissociations. This study was aimed at verifying the use of inorganic phosphate 31 P chemical shift to sense pH variations, and at exploring the complementary use of pyrophosphate ions to cover a wide pH range. A simple set of equations is presented to utilize both phosphate and pyrophosphate 31 P chemical shift in combination for accurate pH determination without a glass electrode over the 5-12 pH range, and without affecting the spectrum of other nuclei. The present study demonstrated an average deviation of 0.09 (maximum <0.2) pH unit from glass electrode measurements. The trimethylphosphate can be used as a suitable chemical shift reference for both 31 P and 1 H (also 13 C), with its hydrolysis being significant only at pH > 12. The method was also demonstrated by determining the pKa of three distinct molecules in a mixture and by comparing the results to those obtained when the glass electrode was used to measure the pH. The approach shown here can be easily tuned to different experimental conditions.

Temporal intra-host variability of mpox virus genomes in multiple body tissues.

Whole-genome sequencing (WGS) has been widely used for the genomic characterization and the phylogenesis of mpox virus (MPXV) 2022 multi-country outbreak. To date, no evidence has been reported on intra-host evolution within samples collected over time from a single patient with long-term infection. Fifty-one samples were collected from five patients at different time points post-symptom onset. All samples were confirmed as MPXV DNA positive, amplified by a multiplexed PCR amplicon, and sequenced by WGS. Complete MPXV genomes were assembled by reference mapping and then aligned to perform phylogenetic and hierarchical clustering analysis. Large intra-host variability was observed among the MPXV genomes sequenced from samples of two immunocompromised with advanced HIV-1 infection patients with prolonged MPXV shedding. Overall, 20 nucleotide mutations were identified in the 32 genomes from HIV patients, differently distributed in samples collected from different tissues and at different time points. No sequence compartmentalization nor variation was observed in the three patients with rapid viral clearance. MPXV exhibits adaptation to changing environments within the infected host and consequently demonstrates tissue compartmentalization. Further studies are needed to elucidate the role of this adaptation in forming a pool of genetic variability and contributing to viral persistence and its clinical implications.

Booster dose of SARS-CoV-2 messenger RNA vaccines strengthens the specific immune response of patients with rheumatoid arthritis: A prospective multicenter longitudinal study.

OBJECTIVES: To characterize the kinetics of humoral and T-cell responses in rheumatoid arthritis (RA)-patients followed up to 4-6 weeks (T3) after the SARS-CoV-2 vaccine booster dose. METHODS: Health care workers (HCWs, n = 38) and patients with RA (n = 52) completing the messenger RNA vaccination schedule were enrolled at T3. In each cohort, 25 subjects were sampled after 5 weeks (T1) and 6 months (T2) from the first vaccine dose. The humoral response was assessed by measuring anti-receptor-binding domain (RBD) and neutralizing antibodies, the T-cell response by interferon-γ-release assay (IGRA), T cell cytokine production, and B cell phenotype at T3 by flow cytometry. RESULTS: Patients with RA showed a significant reduction of antibody titers from T1 to T2 and a significant increase at T3. T-cell response by IGRA persisted over time in patients with RA, whereas it increased in HCWs. Most patients with RA scored positive for anti-RBD, neutralizing antibody and T-cell responses, although the magnitude was lower than HCWs. The spike-specific-cytokine response was mainly clusters of differentiation (CD)4+ T cells restricted in both cohorts and significantly lower with reduced interleukin-2 response and CD4-antigen-responding naïve T cells in patients with RA. Unswitched memory B cells were reduced in patients with RA compared with HCWs independently of vaccination. CONCLUSION: COVID-19 vaccine booster strengthens the humoral immunity in patients with RA even with a reduced cytokine response.

Monoclonal Antibodies for Pre- and Postexposure Prophylaxis of COVID-19: Review of the Literature.

Monoclonal antibodies are laboratory-made proteins that mimic the immune system's ability to fight off harmful microorganisms, including viruses such as Severe Acute Respiratory Syndrome-CoronaVirus-2 (SARS-CoV-2). The US Food and Drug Administration (FDA) and the European Medical Agency (EMA) have already authorized monoclonal antibodies of anti-SARS-CoV-2 to treat mild to moderate CoronaVIrus Disease-2019 (COVID-19) in patients at risk of developing severe disease. More recently, monoclonal antibodies anti-SARS-CoV-2 have been authorized for primary and secondary prophylaxis in patients at high risk of severe disease for background comorbidity. Primary or pre-exposure prophylaxis prevents COVID-19 in unexposed people, whereas secondary or postexposure prophylaxis prevent COVID-19 in recently exposed people to individuals with laboratory-confirmed SARS-CoV-2. This review focuses briefly on therapeutic indications of currently available monoclonal antibodies for COVID-19 pre- and postexposure prophylaxis and on the efficacy of convalescent plasma.

Glyphosate sensing in aqueous solutions by fluorescent zinc(II) complexes of [9]aneN3-based receptors.

Herein we describe the binding abilities of Zn(II) complexes of [12]aneN4- (L1) and [9]aneN3-based receptors (L2, L3) towards the herbicides N-(phosphonomethyl)glycine (glyphosate, H3PMG) and 2-amino-4-[hydroxy(methyl)phosphoryl]butanoic acid (glufosinate, H2GLU), and also aminomethylphosphonic acid (H2AMPA), the main metabolite of H3PMG, and phosphate. All ligands form stable Zn(II) complexes, whose coordination geometries allow a possible interaction of the metal center with exogenous anionic substrates. Potentiometric studies evidenced the marked coordination ability of the L2/Zn(II) system for the analytes considered, with a preferential binding affinity for H3PMG over the other substrates, in a wide range of pH values. 1H and 31P NMR experiments supported the effective coordination of such substrates by the Zn(II) complex of L2, while fluorescence titrations and a test strip experiment were performed to evaluate whether the H3PMG recognition processes could be detected by fluorescence signaling.

Emulation of a Target Trial From Observational Data to Compare Effectiveness of Casirivimab/Imdevimab and Bamlanivimab/Etesevimab for Early Treatment of Non-Hospitalized Patients With COVID-19.

Objectives: Comparative analysis between different monoclonal antibodies (mAbs) against SARS-CoV-2 are lacking. We present an emulation trial from observational data to compare effectiveness of Bamlanivimab/Etesevimab (BAM/ETE) and Casirivimab/Imdevimab (CAS/IMD) in outpatients with early mild-to-moderate COVID-19 in a real-world scenario of variants of concern (VoCs) from Alpha to Delta. Methods: Allocation to treatment was subject to mAbs availability, and the measured factors were not used to determine which combination to use. Patients were followed through day 30. Viral load was measured by cycle threshold (CT) on D1 (baseline) and D7.Primary outcome was time to COVID-19-related hospitalization or death from any cause over days 0-30. Weighted pooled logistic regression and marginal structural Cox model by inverse probability weights were used to compare BAM/ETE vs. CAS/IMD. ANCOVA was used to compare mean D7 CT values by intervention. Models were adjusted for calendar month, MASS score and VoCs. We evaluated effect measure modification by VoCs, vaccination, D1 CT levels and enrolment period. Results: COVID19-related hospitalization or death from any cause occurred in 15 of 237 patients in the BAM/ETE group (6.3%) and in 4 of 196 patients in the CAS/IMD group (2.0%) (relative risk reduction [1 minus the relative risk] 72%; p=0.024). Subset analysis carried no evidence that the effect of the intervention was different across stratification factors. There was no evidence in viral load reduction from baseline through day 7 across the two groups (+0.17, 95% -1.41;+1.74, p=0.83). Among patients who experienced primary outcome, none showed a negative RT-PCR test in nasopharyngeal swab (p=0.009) and 82.4% showed still high viral load (p<0.001) on D7. Conclusions: In a pre-Omicron epidemiologic scenario, CAS/IMD reduced risk of clinical progression of COVID-19 compared to BAM/ETE. This effect was not associated with a concomitant difference in virological response.

A Simulation Model for the Non-Electrogenic Uniport Carrier-Assisted Transport of Ions across Lipid Membranes.

Impressive work has been completed in recent decades on the transmembrane anion transport capability of small synthetic transporters from many different structural classes. However, very few predicting models have been proposed for the fast screening of compound libraries before spending time and resources on the laboratory bench for their synthesis. In this work, a new approach is presented which aims at describing the transport process by taking all the steps into explicit consideration, and includes all possible experiment-derived parameters. The algorithm is able to simulate the macroscopic experiments performed with lipid vesicles to assess the ion-transport ability of the synthetic transporters following a non-electrogenic uniport mechanism. While keeping calculation time affordable, the final goal is the curve-fitting of real experimental data-so, to obtain both an analysis and a predictive tool. The role and the relative weight of the different parameters is discussed and the agreement with the literature is shown by using the simulations of a virtual benchmark case. The fitting of real experimental curves is also shown for two transporters of different structural type.

Aero-Medical Evacuation during SARS-CoV-2 Pandemic: Extraordinary Measure or Emerging Treatment Option?

Aero-medical evacuation has been considered as a feasible and safe treatment option during COVID pandemic, particularly when the needs of affected patients exceed what local clinics and hospitals are supposed to provide. In this article, we analyzed the clinical course of 17 patients medically evacuated to the "L. Spallanzani" Institute in Rome, Italy from foreign countries, mainly Africa and Eastern Europe, who had COVID-19 pneumonia with, or without, coinfections such as malaria, HIV, tuberculosis and microbiologically confirmed sepsis syndrome. The aero-medical evacuation of patients with infectious diseases has become one of the greatest medical achievements we have reached during this pandemic; in fact, only two patients with life threatening coinfections have died. Although logistically difficult and cost consuming, medical evacuation should be considered as a treatment option more than a single extraordinary measure, especially among complex cases that require specific technical and human resources.

No Efficacy of the Combination of Lopinavir/Ritonavir Plus Hydroxychloroquine Versus Standard of Care in Patients Hospitalized With COVID-19: A Non-Randomized Comparison.

Objectives: No specific treatment has been approved for COVID-19. Lopinavir/ritonavir (LPV/r) and hydroxychloroquine (HCQ) have been used with poor results, and a trial showed advantages of combined antiviral therapy vs. single antivirals. The aim of the study was to assess the effectiveness of the combination of antivirals (LPV/r and HCQ) or their single use in COVID-19 hospitalized patients vs. standard of care (SoC). Methods: Patients ≥18 years with SARS-CoV-2 infection, defined as positive RT-PCR from nasal/oropharyngeal (NP/OP) swab or positive serology, admitted at L. Spallanzani Institute (Italy) were included. Primary endpoint: time to invasive ventilation/death. Secondary endpoint: time to two consecutive negative SARS-CoV-2 PCRs in NP/OP swabs. In order to control for measured confounders, a marginal Cox regression model with inverse probability weights was used. Results: A total of 590 patients were included in the analysis: 36.3% female, 64 years (IQR 51-76), and 91% with pneumonia. Cumulative probability of invasive ventilation/death at 14 days was 21.2% (95% CI 17.6, 24.7), without difference between SOC, LPV/r, hydroxychloroquine, HCQ + LPV/r, and SoC. The risk of invasive ventilation/death in the groups appeared to vary by baseline ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FiO2). Overall cumulative probability of confirmed negative nasopharyngeal swabs at 14 days was 44.4% (95% CI 38.9, 49.9), without difference between groups. Conclusion: In this retrospective analysis, we found no difference in the rate of invasive ventilation/death or viral shedding by different strategies, as in randomized trials performed to date. Moreover, even the combination HCQ + LPV/r did not show advantages vs. SoC.

Healthcare-Associated Infections and Antibiotics Consumption: A Comparison of Point Prevalence Studies and Intervention Strategies.

This study compares healthcare-associated infections (HAIs) prevalence and antimicrobial consumption (AMC) from surveys conducted in 2016 and 2019 in an Italian hospital for acute care. HAIs prevalence was 7.1% in both surveys, while patients were under antibiotic treatment slightly increased from 2016 to 2019, from 42.6% to 43.7%, respectively. In the survey of 2016, HAIs risk factors were fatal McCabe score and hospitalization longer than two weeks, while CVC and urinary catheter in that conducted in 2019. In both surveys, CVC and peripheral venous catheter resulted associated to AMC. HAIs and AMC remained stable although the hospital undergone a complexity reduction in the second survey, remarking that critical actions are strictly required implementing infection control practices and antimicrobial stewardship.

Systematic analysis of direct antiglobulin test results in post-artesunate delayed haemolysis.

BACKGROUND: Post-artesunate delayed haemolysis (PADH) is common after severe malaria episodes. PADH is related to the "pitting" phenomenon and the synchronous delayed clearance of once-infected erythrocytes, initially spared during treatment. However, direct antiglobulin test (DAT) positivity has been reported in several PADH cases, suggesting a contribution of immune-mediated erythrocyte clearance. The aim of the present study was to compare clinical features of cases presenting a positive or negative DAT. METHODS: Articles reporting clinical data of patients diagnosed with PADH, for whom DAT had been performed, were collected from PubMed database. Data retrieved from single patients were extracted and univariate analysis was performed in order to identify features potentially related to DAT results and steroids use. RESULTS: Twenty-two studies reporting 39 PADH cases were included: median baseline parasitaemia was 20.8% (IQR: 11.2-30) and DAT was positive in 17 cases (45.5%). Compared to DAT-negative individuals, DAT-positive patients were older (49.5 vs 31; p = 0.01), had a higher baseline parasitaemia (27% vs 17%; p = 0.03) and were more commonly treated with systemic steroids (11 vs 3 patients, p = 0.002). Depth and kinetics of delayed anaemia were not associated with DAT positivity. CONCLUSIONS: In this case series, almost half of the patients affected by PADH had a positive DAT. An obvious difference between the clinical courses of patients presenting with a positive or negative DAT was lacking. This observation suggests that DAT result may not be indicative of a pathogenic role of anti-erythrocytes antibodies in patients affected by PADH, but it may be rather a marker of immune activation.

Prolonged and severe SARS-CoV-2 infection in patients under B-cell-depleting drug successfully treated: A tailored approach.

Prolonged B-cell depletion due to anti-CD20 monoclonal antibody (mAbs) therapy impairs the adaptive immune response, causing severe manifestations during COronaVIrus Disease-2019 (COVID-19). The cases of two patients under anti-CD20 therapy who experienced prolonged and severe COVID-19 successfully treated with mAbs against Severe Acute Respiratory Syndrome-CoV-2 spike proteins are reported.

Artemisinin resistance surveillance in African Plasmodium falciparum isolates from imported malaria cases to Italy.

BACKGROUND: Plasmodium falciparum (P. falciparum) malaria is a significant public health problem in returning travellers, and artemisinin combination therapy (ACT) remains the first choice for treatment. Several single nucleotide polymorphisms (SNPs) in the P. falciparum kelch 13 (Pfk13) gene have been associated with artemisinin (ART) resistance. Moreover, the increase in the P. falciparum plasmepsin 2 (Pfpm2) gene copy number was shown to be linked with reduced susceptibility of P. falciparum to piperaquine (PPQ), a partner drug in an ACT regimen. Active molecular surveillance for imported drug-resistant malaria parasites is a pivotal activity to provide adequate chemoprophylaxis and treatment guidelines. METHODS: A retrospective study to review imported P. falciparum malaria in patients admitted to Spallanzani Institute between 2014 and 2015 was conducted. Information collected included clinic and epidemiological characteristics such as age, gender, country of origin, time since arrival to our country, travel history. All P.falciparum isolates were analysed for SNPs in the Pfk13 gene and for copy number variations in the Pfpm2 gene. RESULTS: P. falciparum malaria was identified in 54 travellers. The mean age was 37 years, 44 were males. All cases were imported from non-EU countries. In the Pfk13 gene two mutations (R561R and F673L) were detected. Six P. falciparum isolates carried two copies of Pfpm2 gene, and one three copies, representing ≈16% of the analysed isolates. CONCLUSIONS: None of the SNPs known to be associated with ART resistance were detected in the examined parasites. Our results provide evidence that Pfpm2 duplications (associated with piperaquine resistance) occur in Africa, emphasizing the necessity to better decode the genetic background associated with PPQ resistance. Further epidemiological investigations in Pfpm2 amplification along with mutations in the Pfk13 gene will be useful for developing and updating anti-malarial guidance in travellers.

Permeation of ß-Lactamase Inhibitors through the General Porins of Gram-Negative Bacteria.

Modern medicine relies upon antibiotics, but we have arrived to the point where our inability to come up with new effective molecules against resistant pathogens, together with the declining private investment, is resulting in the number of untreatable infections increasing worldwide at worrying pace. Among other pathogens, widely recognized institutions have indicated Gram-negative bacteria as particularly challenging, due to the presence of the outer membrane. The very first step in the action of every antibiotic or adjuvant is the permeation through this membrane, with small hydrophilic drugs usually crossing through protein channels. Thus, a detailed understanding of their properties at a molecular level is crucial. By making use of Molecular Dynamics simulations, we compared the two main porins of four members of the Enterobacteriaceae family, and, in this paper, we show their shared geometrical and electrostatic characteristics. Then, we used metadynamics simulations to reconstruct the free energy for permeation of selected diazobicyclooctans through OmpF. We demonstrate how porins features are coupled to those of the translocating species, modulating their passive permeation. In particular, we show that the minimal projection area of a molecule is a better descriptor than its molecular mass or the volume. Together with the magnitude and orientation of the electric dipole moment, these are the crucial parameters to gain an efficient compensation between the entropic and enthalpic contributions to the free energy barrier required for permeation. Our results confirm the possibility to predict the permeability of molecules through porins by using a few molecular parameters and bolster the general model according to which the free energy increase is mostly due to the decrease of conformational entropy, and this can be compensated by a favorable alignment of the electric dipole with respect to the channel intrinsic electric field.

Aza- and Mixed Thia/Aza-Macrocyclic Receptors with Quinoline-Bearing Pendant Arms for Optical Discrimination of Zinc(II) or Cadmium(II) Ions.

The synthesis and coordination properties of two fluorescent chemosensors, featuring [9]aneN3 (1,4,7-triazacyclononane; L1) and [12]aneNS3 (1-aza-4,7,10-trithiacyclododecane; L2) as receptor units, and a quinoline pendant arm with an amide group as a functional group spacer are described. The optical responses of L1 and L2 in the presence of several metal ions were analysed in MeCN/H2 O (1 : 4 v/v) solutions. A selective chelation enhancement of fluorescence (CHEF) effect was observed in the presence of Zn2+ in the case of L1, and in the presence of Cd2+ in the case of L2, following the formation of a 1 : 1 and a 1 : 2 metal/ligand complex, respectively, which was also confirmed by potentiometric measurements. 1 H and 13 C NMR measurements in CD3 CN/CDCl3 in combination with molecular mechanics calculations show that for both complexes of L1 and L2 with Zn2+ and Cd2+ , respectively, the coordination of the carbonyl group from the pendant arm could be the origin of the observed optical selectivity.