Long-term multidisciplinary follow-up programs in pediatric cardiac arrest survivors

Long-term outcome studies after pediatric cardiac arrest (CA) are few. They require a CA registry and dedicated outcome teams. Learning about the long-term outcomes is very important for developing prognostication guidelines, improving post-cardiac care, counseling caregivers about the future of their child, and creating opportunities for therapeutic intervention studies to improve outcomes. Few PICUs worldwide provide a multidisciplinary follow-up program as routine practice at an outpatient clinic with standardized measurements, using validated instruments including neuropsychological assessments by psychologists. The primary goal of such a follow-up program should be to provide excellent care to children and their caregivers, thereby resulting in a high attendance. Pediatric psychologists, neurologists and pediatricians/pediatric intensivists should ideally be involved to screen for delayed development and psychosocial problems and offer appropriate care at the same time. Preferably, outcomes should consist of evaluation of morbidity (physical and neuropsychological), functional health and Health Related Quality Of Life (QoL) of the patient and their caregivers.

Drug-Drug Interaction Between Cannabidiol, Cyclosporine, and Mycophenolate Mofetil: A Case Report

Kidney transplantation remains the optimal therapy for many patients with end-stage kidney disease (ESKD). Chronic pain is one of the most common and distressing symptoms among patients with ESKD, and its treatment is a complex and challenging task to accomplish. The benefits of cannabidiol (CBD) in chronic pain treatment have been reported recently. Cannabidiol is metabolized by cytochrome P450, mainly CYP3A4 and CYP2C19, and can also undergo direct conjugation via UDP-glucuronosyltransferase enzymes, with a growing body of evidence suggesting it is also a potent inhibitor or inducer of these pathways. Cannabidiol was also found to be a potent inhibitor of carboxylesterases in vitro. Because cytochrome P450 enzymes and carboxylesterases are also responsible for the clearance and activation of immunosuppressants, respectively, drug-drug interactions are likely to occur. Here, we report a pharmacokinetic drug interaction between CBD and cyclosporine and mycophenolate mofetil in a patient with ESKD with a kidney transplantation. It is thus crucial to take into account these interactions and monitor drug levels to avoid drug toxicity or a lack of efficacy. This study is in accordance with the guidelines of the Declaration of Helsinki and the Declaration of Istanbul.

Human Data on Pharmacokinetic Interactions of Cannabinoids: A Narrative Review

Concomitant use of cannabinoids with other drugs may result in pharmacokinetic drug-drug interactions, mainly due to the mechanism involving Phase I and Phase II enzymes and/or efflux transporters. Cannabinoids are not only substrates but also inhibitors or inducers of some of these enzymes and/or transporters. This narrative review aims to provide the available information reported in the literature regarding human data on the pharmacokinetic interactions of cannabinoids with other medications. A search on Pubmed/Medline, Google Scholar, and Cochrane Library was performed. Some studies were identified with Google search. Additional articles of interest were obtained through cross-referencing of published literature. All original research papers discussing interactions between cannabinoids, used for medical or recreational/adult-use purposes, and other medications in humans were included. Thirty-two studies with medicinal or recreational/adult-use cannabis were identified (seventeen case reports/series, thirteen clinical trials, and two retrospective analyses). In three of these studies, a bidirectional pharmacokinetic drug-drug interaction was reported. In the rest of the studies, cannabinoids were the perpetrators, as in most of them, concentrations of cannabinoids were not measured. In light of the widespread use of prescribed and non-prescribed cannabinoids with other medications, pharmacokinetic interactions are likely to occur. Physicians should be aware of these potential interactions and closely monitor drug levels and/or responses. The existing literature regarding pharmacokinetic interactions is limited, and for some drugs, studies have relatively small cohorts or are only case reports. Therefore, there is a need for high-quality pharmacological studies on cannabinoid-drug interactions.

Quantitative systems pharmacology Model to characterize valproic acid-induced hyperammonemia and the effect of L-carnitine supplementation

Valproic acid (VPA) is a short-chain fatty acid widely prescribed in the treatment of seizure disorders and epilepsy syndromes, although its therapeutic value may be undermined by its toxicity. VPA serious adverse effects are reported to have a significant and dose-dependent incidence, many associated with VPA-induced hyperammonemia. This effect has been linked with reduced levels of carnitine; an endogenous compound involved in fatty acid's mitochondrial β-oxidation by facilitation of its entrance via the carnitine shuttle. High exposure to VPA can lead to carnitine depletion causing a misbalance between the intra-mitochondrial β-oxidation and the microsomal ω-oxidation, a pathway that produces toxic metabolites such as 4-en-VPA which inhibits ammonia elimination. Moreover, a reduction in carnitine levels might be also related to VPA-induced obesity and lipids disorder. In turn, L-carnitine supplementation (CS) has been recommended and empirically used to reduce VPA's hepatotoxicity. The aim of this work was to develop a Quantitative Systems Pharmacology (QSP) model to characterize VPA-induced hyperammonemia and evaluate the benefits of CS in preventing hyperammonemia under both chronic treatment and after VPA overdosing. The QSP model included a VPA population pharmacokinetics model that allowed the prediction of total and unbound concentrations after single and multiple oral doses considering its saturable binding to plasma proteins. Predictions of time courses for 2-en-VPA, 4-en-DPA, VPA-glucuronide, carnitine, ammonia and urea levels, and for the relative change in fatty acids, Acetyl-CoA, and glutamate reflected the VPA induced changes and the efficacy of the treatment with L-carnitine. The QSP model was implemented to give a rational basis for the L-carnitine dose selection to optimize CS depending on VPA dosage regime and to assess the currently recommended L-carnitine rescue therapy after VPA overdosing. Results show that a L-carnitine dose equal to the double of the VPA dose using the same interdose interval would maintain the ammonia levels at baseline. The QSP model may be expanded in the future to describe other adverse events linked to VPA-induced changes in endogenous compounds.

Emergency Psychiatry before and during COVID-19 pandemia

Introduction

The COVID-19 pandemic had a significant impact worldwide. Consultations in the Emergency Service of the Hospital Clínic of Barcelona varied in terms of reasons for consultations, psychopathology, and other aspects, before and after the pandemic.

Objectives

To examine changes in the profile of patients admitted before and during the COVID-19 pandemic to our Psychiatric Emergency Service.

Methods

All children, adolescent and adult psychiatric inpatients admitted from December 4th 2019 to March 31st 2021 to the Psychiatric Emergency Service of Hospital Clínic of Barcelona, Spain, were retrospectively included for analysis and divided into two groups –groups 1 or 2- including the first one all patients who attended before lockdown and the second group those who attended during the pandemic.

Results

A total of 1991 patients were included -1224 in the first group and 767 in the second group. The majority of patients were male (52.08%), with a mean age of 41.21 years (SD 16.53). A proportion significantly higher of men was found in the second group (p<0.05). The proportion of patients consulting with substance use disorders was significantly higher in the second group (p<0.05). Patients from the second group presented a significantly higher proportion of admissions in an acute psychiatric ward (p<0.05), and also a significantly higher proportion of consultations of patients with dementia (p<0.05).

Conclusions

The COVID-19 pandemic lead to a significant reduction in the overall consultations, with a higher proportion of severe cases. The lack of availability of caregivers and telework might have influenced the increase in consultations of patients with dementia.

Disclosure

AG has received travel and financial support from Janssen, Otsuka-Lundbeck and Angelini, and research support from Instituto de Salud Carlos III, and declares no support related with the subject of this presentation.

Tissue Drug Concentration

Blood flow enables the delivery of oxygen and nutrients to the different tissues of the human body. Drugs follow the same route as oxygen and nutrients; thus, drug concentrations in tissues are highly dependent on the blood flow fraction delivered to each of these tissues. Although the free drug concentration in blood is considered to correlate with pharmacodynamics, the pharmacodynamics of a drug is actually primarily commanded by the concentrations of drug in the aqueous spaces of bodily tissues. However, the concentrations of drug are not homogeneous throughout the tissues, and they rarely reflect the free drug concentration in the blood. This heterogeneity is due to differences in the blood flow fraction delivered to the tissues and also due to membrane transporters, efflux pumps, and metabolic enzymes. The rate of drug elimination from the body (systemic elimination) depends more on the driving force of drug elimination than on the free concentration of drug at the site from which the drug is being eliminated. In fact, the actual free drug concentration in the tissues results from the balance between the input and output rates. In the present paper, we develop a theoretical concept regarding solute partition between intravascular and extravascular spaces; discuss experimental research on aqueous/non-aqueous solute partitioning and clinical research on microdialysis; and present hypotheses to predict in-vivo elimination using parameters of in-vitro metabolism.

The COVID-19 policy response in Spain and Portugal: a study of measures to slow down infection rate

Background

The COVID-19 global pandemic triggered massive policy responses worldwide. Measures taken during the pandemic differed across countries and time. Governance systems may influence the capacity of countries to respond promptly and mobilize the necessary resources in time. Identifying measures and when they appeared are critical questions to assess emergency response strategies. The objective of this study was to analyze the policy response to slow down the infection rate of COVID-19 cases in Portugal and Spain according to timing (related to death rates) and stringency.

Methods

A descriptive comparative study of non-pharmaceutical interventions was conducted through a content analysis of policies and records review of official government sources. Portugal and Spain were selected considering the similarities between national health systems, but different government organization and epidemic impact. The Autonomous Community of Madrid was also included as example of subnational systems. Death rates were retrieved from daily statistics of open secondary sources.

Results

Results show that countries responded with a complex mix of measures across policy sectors, following dynamic patterns established by the epidemic evolution and governance systems. Policies aimed to reduce the spread of the virus, enable individuals and businesses to comply with restrictions, and reinforce National Health System's capacity. The declaration of state of emergency was a critical tool to organize actions under clear leadership, especially in devolved contexts.

Conclusions

Our findings suggest that, in early epidemic phases, a centralized command can be more effective at timely enacting nationwide stringent measures. Evidence from this study contributes to the argument that a fast, robust, and early response might have been more effective at containing spread at the initial stages of the pandemic.

Key messages

The policy response included measured to reduce spread of infection, enhance adherence and strengthen health systems capacity to deal with the pandemic.

The declaration of state of emergency was essential to ensure an organized, coherent, timely, and robust response, especially in devolved contexts.

The role of efflux transporters and metabolizing enzymes in brain and peripheral organs to explain drug-resistant epilepsy

Drug‐resistant epilepsy has been explained by different mechanisms. The most accepted one involves overexpression of multidrug transporters proteins at the blood brain barrier and brain metabolizing enzymes. This hypothesis is one of the main pharmacokinetic reasons that lead to the lack of response of some antiseizure drug substrates of these transporters and enzymes due to their limited entrance into the brain and limited stay at the sites of actions. Although uncontrolled seizures can be the cause of the overexpression, some antiseizure medications themselves can cause such overexpression leading to treatment failure and thus refractoriness. However, it has to be taken into account that the inductive effect of some drugs such as carbamazepine or phenytoin not only impacts on the brain but also on the rest of the body with different intensity, influencing the amount of drug available for the central nervous system. Such induction is not only local drug concentration but also time dependent. In the case of valproic acid, the deficient disposition of ammonia due to a malfunction of the urea cycle, which would have its origin in an intrinsic deficiency of L‐carnitine levels in the patient or by its depletion caused by the action of this antiseizure drug, could lead to drug‐resistant epilepsy. Many efforts have been made to change this situation. In order to name some, the administration of once‐daily dosing of phenytoin or the coadministration of carnitine with valproic acid would be preferable to avoid iatrogenic refractoriness. Another could be the use of an adjuvant drug that down‐regulates the expression of transporters. In this case, the use of cannabidiol with antiseizure properties itself and able to diminish the overexpression of these transporters in the brain could be a novel therapy in order to allow penetration of other antiseizure medications into the brain.

POS0623 CYTOKINE PRODUCTION BY BLOOD LYMPHOCYTES DEFINES A PROFILE ASSOCIATED WITH NON-REMISSION IN PATIENTS WITH RHEUMATOID ARTHRITIS TREATED WITH TNF INHIBITORS

Background:

In clinical practice no more than 50% of the patients treated with TNF inhibitors (TNFi) achieve remission (REM). Previous investigations suggested that peripheral blood mononuclear cells (PBMC) may be markers associated with the TNFi treatment success1.

Objectives:

This study aims to analyse the intracellular cytokine production by PBMC and its association with REM achievement after 6 months (m) of TNFi treatment in patients with RA.

Methods:

This was a prospective study including 62 patients with RA starting the 1st TNFi. PBMC were isolated from patients at baseline and after 6m of treatment with TNFi and cryopreserved until studied. In vitro stimulation and intracellular cytokine production by PBMC was performed as follow: in the presence of 2µg/mL brefeldin and 2µmol/L monensin monocytes were stimulated with 20ng/mL LPS during 4h whereas lymphocytes were stimulated with 50ng/mL phorbol 12-myristate 13-acetate and 750ng/mL ionomycin for 4h at 37°C. To identify IL10-producing B cells, PBMC were pre-incubated with 3µg/mL of CpG oligonucleotide during 20h at 37°C prior to stimulation. Intracellular cytokine production (TNFα, IL6, GM-CSF, IL10) by the different cell subsets (monocytes, CD4+ and CD8+ T cells, naïve and memory B cells) was analysed by flow-cytometry. Clinical activity at baseline and after 6m was assessed by DAS28-ESR. REM was defined as DAS28≤2.6 at 6m. The association between cytokine production by each PBMC subset and REM was analysed through univariable and multivariable logistic regression models. Receiving operating curve (ROC) analysis was used to select the optimal ratio of cytokine production associated with REM status.

Results:

After 6m of TNFi treatment, 30 (48%) patients achieved REM. No significant differences between REM and non-REM groups were observed for patients’ characteristics at baseline except for DAS28, which was lower in the REM group (non-REM: 5.4±0.9; REM: 4.3±0.9; p<0.0001) (Table 1). Therefore, further analyses were adjusted by baseline DAS28. A lower ratio between calculated with the IL10 and TNFα production by B cells and by CD4+ T cells (IL10 B/TNF CD4) at 6m was found for non-REM patients (non-REM: 0.31 vs REM: 0.54; p=0.007). Based on a ROC analysis, we found that a (IL10 B/TNF CD4)<0.54 at 6 m was significantly associated with a higher probability of non-REM at 6 months (OR: 5.0; 95% CI: 1.1-21.7) (Figure 1).

Table 1.

Baseline predictors of reduction of disease activity at 12 months from start of abatacept. Linear regression.

Baseline patients’ characteristicsTotal patients (n=62)DAS28>2.6(n=32; 52%)DAS28≤2.6(n=30; 48%)p-valueAge (years)53±1253±1352±100.8Female55 (89)30 (94)25 (83)0.2Disease duration (years)8 (4-11)8 (4-12)7 (3-11)0.7RF positive49 (79)23 (72)26 (87)0.1ACPA positive54 (87)26 (81)28 (93)0.2Smoking habit (n=55)0.2Non-smokers26 (47)16 (55)10 (38) Smoker29 (53)13 (45)16 (51)Body mass index (kg/m2)25.9±5.625.8±5.726.0±5.60.9DAS284.9±1.05.4±0.94.3±0.9<0.0001Concomitant csDMARDs60 (97)32 (100)28 (93)0.3MTX [±OD]46 (74)26 (81)20 (67)0.3Only OD14 (23)6 (19)8 (26)0.3Prednisone36 (58)19 (59)17 (57)0.9

Conclusion:

Our results show that the proinflammatory IL10 B/TNF CD4 ratio is associated with non-REM status. It could be useful to analyse the success of TNFi treatment in patients with RA.

References:

[1]Rodríguez-Martín E, et al. Front Immunol. 2020; 11: 1913.

Acknowledgements:

ISCIII (PI16/00474; PI16/01092)

Disclosure of Interests:

Borja Hernández-Breijo: None declared, Eulalia Rodríguez-Martín: None declared, Carlota García-Hoz: None declared, Victoria Navarro-Compán Speakers bureau: Abbvie, Janssen, Lilly, MSD, Novartis, Pfizer and UCB, Grant/research support from: Abbvie, Janssen, Lilly, MSD, Novartis, Pfizer and UCB, Cristina Sobrino: None declared, ANA MARTÍNEZ-FEITO: None declared, Israel Nieto-Gañán: None declared, Javier Bachiller-Corral Speakers bureau: Abbvie, MSD, BMS and Roche, Grant/research support from: Pfizer, Paloma Lapuente-Suanzes: None declared, Gemma Bonilla: None declared, Cristina Pijoán-Moratalla: None declared, Mónica Vázquez: None declared, Alejandro Balsa Speakers bureau: Abbvie, BMS, Nordic, Novartis, Pfizer, Sandoz, Sanofi, Roche and UCB, DORA PASCUAL-SALCEDO: None declared, Luisa María Villar: None declared, Chamaida Plasencia Speakers bureau: AbbVie, Lilly, Novartis, Pfizer, Sanofi, Biogen and UCB

A data base of contributions of major oceanic and terrestrial moisture sources on continental daily extreme precipitation

Most of the moisture transported in the globe has its origin in the well-known main moisture sources defined by Gimeno et al. [1]. They provide moisture for precipitation over continental areas in the world in different proportions. This paper presents the daily moisture contribution over each 0.5 × 0.5 continental gridded point from the three preferred moisture sources (primary, secondary, and tertiary) for continental extreme precipitation during the Peak Precipitation Month. The data consist of the moisture contribution (|E−P<0|) field by month from the three preferred sources obtained using an approach based on the Lagrangian particle dispersion model FLEXPART. The data here presented is directly related to the results presented in Vazquez et al. [2].

Clinical Pharmacokinetics of Cannabinoids and Potential Drug-Drug Interactions

Over the past few years, considerable attention has focused on cannabidiol (CBD) and Δ⁹-tetrahydrocannabinol (THC), the two major constituents of Cannabis sativa, mainly due to the promising potential medical uses they have shown. However, more information on the fate of these cannabinoids in human subjects is still needed and there is limited research on the pharmacokinetic drug-drug interactions that can occur in the clinical setting and their prevalence. As the use of cannabinoids is substantially increasing for many indications and they are not the first-line therapy in any treatment, health care professionals must be aware of drug-drug interactions during their use as serious adverse events can happen related with toxic or ineffective outcomes. The present chapter overview summarizes our current knowledge on the pharmacokinetics and metabolic fate of CBD and THC in humans and discusses relevant drug-drug interactions, giving a plausible explanation to facilitate further research in the area.

Potential Therapeutic Role of Carnitine and Acetylcarnitine in Neurological Disorders

BACKGROUND

Current therapy of neurological disorders has several limitations. Although a high number of drugs are clinically available, several subjects do not achieve full symptomatic remission. In recent years, there has been an increasing interest in the therapeutic potential of L-carnitine (LCAR) and acetyl-L-carnitine (ALCAR) because of the multiplicity of actions they exert in energy metabolism, as antioxidants, neuromodulators and neuroprotectors. They also show excellent safety and tolerability profile.

OBJECTIVE

To assess the role of LCAR and ALCAR in neurological disorders.

METHODS

A meticulous review of the literature was conducted in order to establish the linkage between LCAR and ALCAR and neurological diseases.

RESULTS

LCAR and ALCAR mechanisms and effects were studied for Alzheimer's disease, depression, neuropathic pain, bipolar disorder, Parkinson's disease and epilepsy in the elderly. Both substances exert their actions mainly on primary metabolism, enhancing energy production, through β-oxidation, and the ammonia elimination via urea cycle promotion. These systemic actions impact positively on the Central Nervous System state, as Ammonia and energy depletion seem to underlie most of the neurotoxic events, such as inflammation, oxidative stress, membrane degeneration, and neurotransmitters disbalances, present in neurological disorders, mainly in the elderly. The impact on bipolar disorder is controversial. LCAR absorption seems to be impaired in the elderly due to the decrease of active transportation; therefore, ALCAR seems to be the more effective option to administer.

CONCLUSION

ALCAR emerges as a simple, economical and safe adjuvant option in order to impair the progression of most neurological disorders.

Computational modelling of nasal respiratory flow

CFD has emerged as a promising diagnostic tool for clinical trials, with tremendous potential. However, for real clinical applications to be useful, overall statistical findings from large population samples (e.g., multiple cases and models) are needed. Fully resolved solutions are not a priority, but rather rapid solutions with fast turn-around times are desired. This leads to the issue of what are the minimum modelling criteria for achieving adequate accuracy in respiratory flows for large-scale clinical applications, with a view to rapid turnaround times. This study simulated a highly-resolved solution using the large eddy simulation (LES) method as a reference case for comparison with lower resolution models that included larger time steps and no turbulence modelling. Differences in solutions were quantified by pressure loss, flow resistance, unsteadiness, turbulence intensity, and hysteresis effects from multiple cycles. The results demonstrated that sufficient accuracy could be achieved with lower resolution models if the mean flow was considered. Furthermore, to achieve an established transient result unaffected by the initial start-up quiescent effects, the results need to be taken from at least the second respiration cycle. It was also found that the exhalation phase exhibited strong turbulence. The results are expected to provide guidance for future modelling efforts for clinical and engineering applications requiring large numbers of cases using simplified modelling approaches.

Potential Pharmacokinetic Drug-Drug Interactions between Cannabinoids and Drugs Used for Chronic Pain

Choosing an appropriate treatment for chronic pain remains problematic, and despite the available medication for its treatment, still, many patients complain about pain and appeal to the use of cannabis derivatives for pain control. However, few data have been provided to clinicians about the pharmacokinetic drug-drug interactions of cannabinoids with other concomitant administered medications. Therefore, the aim of this brief review is to assess the interactions between cannabinoids and pain medication through drug transporters (ATP-binding cassette superfamily members) and/or metabolizing enzymes (cytochromes P450 and glucuronyl transferases).

Unravelling potential severe psychiatric repercussions on healthcare professionals during the COVID-19 crisis

The coronavirus disease 2019 (COVID-19) outbreak is putting healthcare professionals, especially those in the frontline, under extreme pressures, with a high risk of experiencing physical exhaustion, psychological disturbances, stigmatization, insomnia, depression and anxiety. We report the case of a general practitioner, without relevant somatic or psychiatric history that experienced a "brief reactive psychosis (298.8)" under stressful circumstances derived from COVID-19. She presented with delusional ideas of catastrophe regarding the current pandemic situation, delusions of self-reference, surveillance and persecution, with high affective and behavioural involvement. Physical examination and all further additional investigations did not reveal any secondary causes. She was administered olanzapine 10 mg with significant psychopathological improvement being later discharged with indications to maintain the treatment. To our knowledge this is the first reported case of severe mental illness in a healthcare professional without previous psychiatric history due to COVID-19 outbreak. Around 85% of patients presenting a brief psychotic disorder will develop a potentially disabling serious psychotic illness in the long-term. This case represents the potentially serious mental health consequences on healthcare professionals throughout the COVID-19 crisis and emphasizes the need to implement urgent measures to maintain staff mental health during the current pandemic.

Clinical pharmacology of cannabidiol in refractory epilepsy

OBJECTIVE

The aim of this article is to provide a systematic and updated review  on the pharmacology of cannabidiol in the context of refractory epilepsy, with  special emphasis on its pharmacokinetics, adverse drug reactions and drug-drug interactions.

METHOD

A review of the literature related to cannabidiol pharmacokinetics, adverse drug reactions and drug-drug interactions was  carried out in the context of refractory epilepsy, through a search in PubMed and LILACS.

RESULTS

Original studies that exhaustively describe the pharmacokinetics of  cannabidiol are limited but informative. Cannabidiol is rapidly absorbed and its  bioavailability increases when administered with high fat meals. Cannabidiol  exhibits a linear pharmacokinetic profile for doses up to 3,000 mg/day and  accumulates after multiple administrations. Elimination half-life has been  reported between 14 h and 60 h depending on the sampling times of each  study; changes in cannabidiol elimination due to continuous administration  cannot be discarded. Of all reported drugdrug interactions with anticonvulsants  or other co-administered drugs in patients with epilepsy, the strongest evidence  is provided with clobazam. The most frequent cannabidiol-related adverse drug  reactions were low to moderate and included somnolence, mainly related to  concomitant administration of clobazam, and gastrointestinal alterations. Also,  liver function abnormalities were reported during the use of cannabidiol and valproic acid.

CONCLUSIONS

Given the increased use of cannabidiol in refractory epilepsy, a  comprehensive understanding of its pharmacological profile is essential for the  clinical team. Specifically, clinical pharmacists play an important role in  monitoring cannabidiol's safety and efficacy. This approach leads to treatment  optimization, allowing to maximizing the pharmacological activity and minimizing the occurrence of adverse events as well as drug-to-drug interactions. Clinical  follow-up is essential to avoid discontinuation of treatment or exacerbation of  adverse events, which may impair the patients' quality of life.

Pharmacokinetics of Subcutaneous Levetiracetam in Palliative Care Patients

Background: Seizure control is challenging in the palliative care setting. Subcutaneous (SC) levetiracetam (LEV) is currently an off-label route of administration and effectiveness, tolerability, and pharmacokinetics studies for this route are scarce. Objectives: This prospective study aimed at evaluating effectiveness and tolerability of SC LEV as well as characterizing its pharmacokinetics. Subjects: Patients (n = 7) who attended the palliative care clinic between September 2018 and January 2019 with diagnosis of seizures, ≥18 years, and in need of SC route of administration were included in the study. Measurements: LEV plasma levels were determined using high-performance liquid chromatography and pharmacokinetic analysis were performed using Monolix 2018R2 (France). pH and osmolality of the three SC infusion solutions were also determined. Results: Seven patients took part in the study. Seizures were controlled in six out of seven patients with doses of 1000 and 3000 mg/day. Adverse effects were mild. pH and osmolality of the SC infusion solutions were within the accepted values reported in the literature. Mean plasma LEV concentrations were 14.4 mg/L (1000 mg/day) and 27.7 mg/L (2000 mg/day). The population clearance (2.5 L/h) and the elimination half-life (10.4 hours) were successfully estimated. Conclusions: Based on this data, SC LEV was effective and well tolerated. Pharmacokinetic parameters for the SC route were successfully determined.

Sensitivity analysis of a strongly-coupled human-based electromechanical cardiac model: Effect of mechanical parameters on physiologically relevant biomarkers

The human heart beats as a result of multiscale nonlinear dynamics coupling subcellular to whole organ processes, achieving electrophysiologically-driven mechanical contraction. Computational cardiac modelling and simulation have achieved a great degree of maturity, both in terms of mathematical models of underlying biophysical processes and the development of simulation software. In this study, we present the detailed description of a human-based physiologically-based, and fully-coupled ventricular electromechanical modelling and simulation framework, and a sensitivity analysis focused on its mechanical properties. The biophysical detail of the model, from ionic to whole-organ, is crucial to enable future simulations of disease and drug action. Key novelties include the coupling of state-of-the-art human-based electrophysiology membrane kinetics, excitation-contraction and active contraction models, and the incorporation of a pre-stress model to allow for pre-stressing and pre-loading the ventricles in a dynamical regime. Through high performance computing simulations, we demonstrate that 50% to 200% - 1000% variations in key parameters result in changes in clinically-relevant mechanical biomarkers ranging from diseased to healthy values in clinical studies. Furthermore mechanical biomarkers are primarily affected by only one or two parameters. Specifically, ejection fraction is dominated by the scaling parameter of the active tension model and its scaling parameter in the normal direction ( k ort 2 ); the end systolic pressure is dominated by the pressure at which the ejection phase is triggered ( P ej ) and the compliance of the Windkessel fluid model ( C ); and the longitudinal fractional shortening is dominated by the fibre angle ( ϕ ) and k ort 2 . The wall thickening does not seem to be clearly dominated by any of the considered input parameters. In summary, this study presents in detail the description and implementation of a human-based coupled electromechanical modelling and simulation framework, and a high performance computing study on the sensitivity of mechanical biomarkers to key model parameters. The tools and knowledge generated enable future investigations into disease and drug action on human ventricles.

Plasmonic coupling in closed-packed ordered gallium nanoparticles

Plasmonic gallium (Ga) nanoparticles (NPs) are well known to exhibit good performance in numerous applications such as surface enhanced fluorescence and Raman spectroscopy or biosensing. However, to reach the optimal optical performance, the strength of the localized surface plasmon resonances (LSPRs) must be enhanced particularly by suitable narrowing the NP size distribution among other factors. With this purpose, our last work demonstrated the production of hexagonal ordered arrays of Ga NPs by using templates of aluminium (Al) shallow pit arrays, whose LSPRs were observed in the VIS region. The quantitative analysis of the optical properties by spectroscopic ellipsometry confirmed an outstanding improvement of the LSPR intensity and full width at half maximum (FWHM) due to the imposed ordering. Here, by engineering the template dimensions, and therefore by tuning Ga NPs size, we expand the LSPRs of the Ga NPs to cover a wider range of the electromagnetic spectrum from the UV to the IR regions. More interestingly, the factors that cause this optical performance improvement are studied with the universal plasmon ruler equation, supported with discrete dipole approximation simulations. The results allow us to conclude that the plasmonic coupling between NPs originated in the ordered systems is the main cause for the optimized optical response.

Fluid-structure interaction simulations outperform computational fluid dynamics in the description of thoracic aorta haemodynamics and in the differentiation of progressive dilation in Marfan syndrome patients

Abnormal fluid dynamics at the ascending aorta may be at the origin of aortic aneurysms. This study was aimed at comparing the performance of computational fluid dynamics (CFD) and fluid-structure interaction (FSI) simulations against four-dimensional (4D) flow magnetic resonance imaging (MRI) data; and to assess the capacity of advanced fluid dynamics markers to stratify aneurysm progression risk. Eight Marfan syndrome (MFS) patients, four with stable and four with dilating aneurysms of the proximal aorta, and four healthy controls were studied. FSI and CFD simulations were performed with MRI-derived geometry, inlet velocity field and Young's modulus. Flow displacement, jet angle and maximum velocity evaluated from FSI and CFD simulations were compared to 4D flow MRI data. A dimensionless parameter, the shear stress ratio (SSR), was evaluated from FSI and CFD simulations and assessed as potential correlate of aneurysm progression. FSI simulations successfully matched MRI data regarding descending to ascending aorta flow rates (R 2 = 0.92) and pulse wave velocity (R 2 = 0.99). Compared to CFD, FSI simulations showed significantly lower percentage errors in ascending and descending aorta in flow displacement (-46% ascending, -41% descending), jet angle (-28% ascending, -50% descending) and maximum velocity (-37% ascending, -34% descending) with respect to 4D flow MRI. FSI- but not CFD-derived SSR differentiated between stable and dilating MFS patients. Fluid dynamic simulations of the thoracic aorta require fluid-solid interaction to properly reproduce complex haemodynamics. FSI- but not CFD-derived SSR could help stratifying MFS patients.

Sex-by-formulation interaction in bioequivalence studies: the importance of formulations and experimental conditions

In a recently published investigation, the authors argued against the likelihood of sex-based subject-by-formulation interactions in bioequivalence studies, i.e. male and female subjects exhibiting different discriminatory potential to detect bioavailability differences between formulations. The researchers performed a strong methodological study showing the increased probability of false-positive findings in exploratory subgroup analysis, a well-known and documented statistical issue. Indeed, the main limitation of assessing a sex-by-formulation interaction in average bioequivalence studies lies in the fact that these clinical trials are not designed for this purpose. In this commentary, we further discuss on why the impact of sex differences in gastrointestinal physiology over in vivo drug dissolution and absorption rate cannot remain hidden behind statistical limitations, particularly when average bioequivalence conclusions could be affected. Regulatory agencies should encourage and support these important issues related to biopharmaceutical quality of drug products in both sexes. In addition, a sex-based analysis of bioequivalence results will enhance the representativeness of conclusions and provide important information regarding formulation performance, thereby promoting the efficacy and safety of generic drugs and reducing consumer risk. The extrapolation of study conclusions from one sex to another is far away from being scientifically proven.

[Turicella otitidis, contributions to its role in the etiology of ear infections]

OBJECTIVE

Turicella otitidis is a gram-positive bacillus coryneforme described, after 16S RNA sequencing, in 1994 by Funke et al as a microorganism involved in otitis media, and it is in health conditions a habitual colonizer of the external auditory canal. Since its description, more than twenty years ago, few cases of otitis related to or directly attributed to this microorganism have been published.

METHODS

Description of a case of mastoiditis that required surgery and other cases of otic pathology in which T. otitidis was isolated, in the second semester of 2017 in our institution. They were reported only when they grew in pure culture. The identification was made by mass spectrophotometry and an antibiogram was performed.

RESULTS

In our institution in the second half of 2017, 5 cases of otitis media were documented, some of them complicated, in which T. otitidis was isolated. The most of patients were children with recurrent otic pathology, and in some cases the sample was taken before the administration of antibiotics.

CONCLUSIONS

Since the inclusion of new vaccines that protect against microorganisms typically causing otitis media, is possible there are a change in the etiology of this disease and that microorganisms anecdotally isolated until now have become protagonists. The improvement in the microbiological identification provided by tools such as mass spectrometry will help to clarify if there are or not a change in the etiology of these diseases.

Increased prevalence of asymptomatic vertebral fractures in HIV-infected patients over 50 years of age

The prevalence of asymptomatic vertebral fracture in HIV-infected patients over 50 was 20%, associated with older age, male sex, longer time since HIV diagnosis, and tubular renal alterations. Vertebral fractures were independent of osteoporosis at lumbar spine, and were not predicted by the use of the FRAX equation.

PURPOSE

Vertebral fractures (VF) are the hallmark of osteoporotic fractures. Our objective was to determine the prevalence of asymptomatic VF and associated factors in HIV-infected patients over 50 years, and the role of FRAX equation.

METHODS

In a cross-sectional study, a diagnosis of VF was established by the semiquantitative method of Genant in thoracic and lumbar radiographs. Simultaneously, a dual X-ray absorptiometry (DXA), bone and kidney-related analytical, calcium intake, physical exercise, HIV-related factors, and FRAX estimation were evaluated.

RESULTS

Overall, 128 patients (35 women, 27%) were included. Mean age was 57 years. Hypophosphatemia and tubular renal dysfunction were observed in 13 and 21%. DXA scan showed osteopenia and osteoporosis at hip in 65 and 7% of patients, and in spine in 39 and 34%, respectively. VF were observed in 26 patients (20%), with a trend to be associated with lower serum phosphate, increased alkaline phosphatase, and with lower daily calcium intake. In a multivariate analysis, older age (OR 1.2 per year; 14% of VF at 50-55; 44% at 65-70), male sex (26 vs 6%), longer time since HIV diagnosis, and renal and tubular dysfunction were the associated factors. VF were not related with osteoporosis at lumbar spine, and could not be predicted by the FRAX equation.

CONCLUSIONS

The prevalence of asymptomatic vertebral fractures is high in HIV-infected patients older than 50 years, and is not identified by the presence of osteoporosis in spine neither predicted by the FRAX equation. Spine and lumbar X-rays should be routinely performed in this aging population.

Influence of the Histopathological Features of the Lesion on the Diagnostic Yield of Fine-Needle Aspiration Cytology of Pancreatic Solid Lesions

OBJECTIVE

The rate of pancreatic lesions has increased in recent decades due to the widespread use of advanced imaging techniques. Nowadays, a significant proportion of cases are incidentally discovered in asymptomatic patients and cytology is an important tool for the diagnosis and multidisciplinary management of these cases.

STUDY DESIGN

In this study we retrospectively review the experience with pancreatic fine-needle aspiration cytology in the last 17 years at a single large tertiary hospital in Madrid, Spain.

RESULTS

Our results indicate that more than 60% of pancreatic malignant lesions are cytologically confirmed before surgery and 30% of the patients are asymptomatic. Despite this, we have noted that the total number of malignant lesions surgically resected in our hospital has basically remained unchanged over the years, because incidental diagnosis is not always synonymous with resectability and a substantial number of patients are already metastatic at the time of diagnosis. Our series also shows an increase in the number of neuroendocrine tumors, which now represent almost 20% of all cytological diagnoses at our hospital. The sensitivity in our series is 70% and the false negative rate remains 30%, despite sample quality control by experienced cytologists and standardized technical conditions. Fibrosis and necrosis are the 2 features of the primary tumor that significantly and negatively influence the accuracy of cytologic diagnosis.

CONCLUSION

We herein report our experience with cytologic diagnosis of pancreatic lesions in a single tertiary hospital. Our results confirm that cytology is a safe, reliable, and important tool for pancreatic lesion diagnosis and management.

Integration of in vitro biorelevant dissolution and in silico PBPK model of carvedilol to predict bioequivalence of oral drug products

Bioequivalence implementation in developing countries where a high proportion of similar drug products are being marketed has found several obstacles, impeding regulatory agencies to move forward with this policy. Biopharmaceutical quality of these products, several of which are massively prescribed, remains unknown. In this context, an in vitro-in silico-in vivo approach is proposed as a mean to screen product performance and target specific formulations for bioequivalence assessment. By coupling in vitro biorelevant dissolution testing in USP-4 Apparatus (flow-through cell) with physiologically-based pharmacokinetic (PBPK) modeling in PK-Sim® software (Bayer, Germany), the performance of seven similar products of carvedilol tablets containing 25 mg available in the Uruguayan market were compared with the brand-name drug Dilatrend®. In silico simulations for Dilatrend® were compared with published results of bioequivalence studies performed in fasting conditions allowing model development through a learning and confirming process. Single-dose pharmacokinetic profiles were then simulated for the brand-name drug and two similar drug products selected according to in vitro observations, in a virtual Caucasian population of 1000 subjects (50% male, aged between 18 and 50 years with standard body-weights). Population bioequivalence ratios were estimated revealing that in vitro differences in drug release would have a major impact in carvedilol maximum plasma concentration, leading to a non-bioequivalence outcome. Predictions support the need to perform in vivo bioequivalence for these products of extensive use. Application of the in vitro-in silico-in vivo approach stands as an interesting alternative to tackle and reduce drug product variability in biopharmaceutical quality.

Antidot patterned single and bilayer thin films based on ferrimagnetic Tb-Co alloy with perpendicular magnetic anisotropy

Hysteresis properties and magnetization reversal in TbCo(30 nm) and FeNi(10 nm)/TbCo(30 nm) films with nanoscale antidot lattices are investigated to test the effect of nanoholes on the perpendicular anisotropy in the TbCo layer and the induced exchange bias in the FeNi layer. The antidots are introduced by depositing the films on top of hexagonally ordered porous anodic alumina substrates with pore diameter and interpore distance fixed to 75 nm and 105 nm, respectively. The analysis of combined vibrating sample magnetometry, Kerr microscopy and magnetic force microscopy imaging measurements has allowed us to link macroscopic and local magnetization reversal processes. For magnetically hard TbCo films, we demonstrate the tunability of magnetic anisotropy and coercive field (i.e., it increases from 0.2 T for the continuous film to 0.5 T for the antidot film). For the antidot FeNi/TbCo film, magnetization of FeNi is confirmed to be in plane. Although an exchange bias has been locally detected in the FeNi layer, the integrated hysteresis loop has increased coercivity and zero shift along the field axis due to the significantly decreased magnetic anisotropy of TbCo layer.

Investigation of split CoFeB/Ta/CoFeB/MgO stacks for magnetic memories applications

We report on the static and dynamic magnetic properties of W/CoFeB/Ta/CoFeB/MgO stacks, where the CoFeB layer is split in two by a 0.3 nm-thick Ta "dusting" layer. A total CoFeB thickness between 1.2 and 2.4 nm is studied. Perpendicular magnetic anisotropy is obtained for thickness below 1.8 nm even at the as-deposited stacks, and it is enhanced after annealing. Saturation magnetization is 1520 (1440) kA/m before (after) annealing, increased compared to non-split CoFeB layers. Ferromagnetic resonance measurements show that high magnetic anisotropy energy may be achieved (effective anisotropy field 0.571 ± 0.003 T), combined to a moderate Gilbert damping (0.030 ± 0.001). We argue that the above characteristics make the split-CoFeB system advantageous for spintronics applications.

Multisegmented Nanowires: a Step towards the Control of the Domain Wall Configuration

Cylindrical nanowires synthesized by controlled electrodeposition constitute excellent strategic candidates to engineer magnetic domain configurations. In this work, multisegmented CoNi/Ni nanowires are synthesized for tailoring a periodic magnetic structure determined by the balance between magnetocrystalline and magnetostatic energies. High-resolution Transmission Electron Microscopy confirms the segmented growth and the sharp transition between layers. Although both CoNi and Ni segments have similar fcc cubic crystal symmetry, their magnetic configuration is quite different as experimentally revealed by Magnetic Force Microscopy (MFM) imaging. While the Ni segments are single domain with axial magnetization direction, the CoNi segments present two main configurations: a single vortex state or a complex multivortex magnetic configuration, which is further interpreted with the help of micromagnetic simulations. This original outcome is ascribed to the tight competition between anisotropies. The almost monocrystalline fcc structure of the CoNi segments, as revealed by the electron diffraction patterns, which is atypical for its composition, contributes to balance the magnetocrystalline and shape anisotropies. The results of MFM measurements performed under in-plane magnetic field demonstrate that it is possible to switch from the multivortex configuration to a single vortex configuration with low magnetic fields.

L-Carnitine supplementation to reverse hyperammonemia in a patient undergoing chronic valproic acid treatment: A case report

Valproic acid is a broad-spectrum anticonvulsant that has also gained attention in the psychiatric setting. With respect to safety, valproic acid may induce a seemingly rare condition, hyperammonemia, which can induce a wide variety of symptoms ranging from irritability to coma. The proposed mechanism of hyperammonemia involves depletion of carnitine and overproduction of a toxic metabolite, 4-en-valproic acid, both of which impair the urea cycle and thus ammonia elimination. Carnitine is a commonly used antidote for acute intoxication of valproic acid, but is not a therapeutic option for management of chronic adults with adverse effects related to valproic acid. We herein report a case involving a woman with epilepsy who developed hyperammonemia after a change in her anticonvulsant therapy. She reported increased seizures and gastrointestinal disturbances. Her ammonia, valproic acid, 4-en-valproic acid, and carnitine levels were monitored. Her ammonia level was elevated and her carnitine level was at the inferior limit of the population range. She was supplemented with carnitine at 1 g/day. After 1 month, her ammonia level decreased, her carnitine level increased, and her seizures were better controlled. Carnitine supplementation was useful for reversal of her hyperammonemia, allowing her to continue valproic acid for seizure control.

Nanoparticle functionalized laser patterned substrate: an innovative route towards low cost biomimetic platforms

Integration of nanotechnology and advanced manufacturing processes presents an attractive route to produce devices for adaptive biomedical device technologies.

Sex Effect on Average Bioequivalence

PURPOSE

Generic formulations are by far the most prescribed drugs. This scenario is highly beneficial for society because medication expenses are significantly reduced after expiration of the exclusivity period conceded to the branded name drug. Correspondingly, these formulations must be adequately evaluated to avoid drug inefficacy and toxicity in the overall patient population. Bioequivalence studies are the only in vivo evaluation that a generic drug must overcome to reach the market. These clinical trials have not been exempt from underrepresentation of female subjects and a lack of sex-based analysis. Frequently, conclusions obtained in men are extrapolated to women. Furthermore, the obtained results are not analyzed to determine sex differences. The aim of this study was to discuss the effect that male and female differences in gastrointestinal physiology can have on bioequivalence conclusions and to show why a sex-based analysis must be conducted in these studies to improve the evaluation of generic drugs.

METHODS

This discussion was based on observed sex differences in product bioavailability discrimination (sex-by-formulation interaction) and on residual variability through an analysis of average bioequivalence data previously reported by other researchers and data collected by our center. Bioequivalence studies of oral formulations, with a 2-period, 2-sequence, 2-treatment random crossover design performed in healthy subjects with at least 6 subjects of each sex, were included. In addition, the bioequivalence conclusion that would have been reached in each study if performed with only 1 sex was estimated.

FINDINGS

The data reveal that differences in both product bioavailability discrimination and residual variability occur with a significant incidence in bioequivalence studies. In either C_max or AUC, a significant sex-by-formulation interaction was present in 1 of 3 reviewed studies, whereas differences in residual variability between sexes were significant for >50% of studies. Moreover, the performed estimations suggest that the reported bioequivalence conclusions were not verified in at least 1 sex for 1 of 3 studies and were not verified in men and in women for 1 of 6 studies.

IMPLICATIONS

This research shows that extrapolation of bioequivalence results from the male population to the female population is not always valid. Bioequivalence studies must therefore be performed with both male and female subjects in similar proportions. Sex-based analysis in bioequivalence can improve study design, enhance the representativeness of conclusions, and provide important information regarding formulation performance, thereby promoting the efficacy and safety of generic drugs.

Kinetico-mechanistic Studies on the Substitution Reactivity on the {Ru(II)(bpy)2} Core with Nucleosides and Nucleotides at Physiological pH

The kinetico-mechanistic study of the substitution reactions of the aquo ligands in cis-[Ru(bpy)2(H2O)2](2+) by different nucleotides and nucleosides has been conducted at pH close to the physiological value. The concentration dependence and thermal and pressure activation parameters have been measured to ascertain the activation via which reactions take place. Substitution processes are found associatively activated for nitrogen-bonded nucleosides or nucleotides, with outer-sphere hydrogen-bonded aggregates being determinant. For reactions leading to oxygen-bonded nucleotides, the process is clearly dissociatively activated. A selectively induced lability of the inert {Ru(II)(bpy)2} core is observed on the formation of nitrogen(amide)-bonded complexes at relatively low pH values, which might be relevant for the effective intercalation of designed, ruthenium(II)-bonded, aromatic rings.

Complete dataset for 2-treatment, 2-sequence, 2-period efavirenz bioequivalence study conducted with nightly dosing

The efavirenz pharmacokinetic raw data presented in this article was obtained in an average bioequivalence study between a local brand and Stocrin (Merck Sharp & Dohme, purchased from Australia, batch H009175, expiration date November 2013). Dose was administered at night (9:00 p.m.) two hours after food intake. Fourteen healthy subjects, 8 women and 6 men, completed the study. For each subject, 15 data points until 96 h post-administration are included. Subject demographic characteristics and sequences of administration are provided along with individual pharmacokinetic profiles of efavirenz obtained for both formulations after a single oral dose of 600 mg. This data provides information in support of the research article “Sex-by-formulation interaction assessed through a bioequivalence study of efavirenz tablets” [1].

Sex-by-formulation interaction assessed through a bioequivalence study of efavirenz tablets

Although sex-related differences in gastrointestinal physiology have been vastly reported, its impact on drug oral bioavailability and bioequivalence (product discrimination) is often ignored. On this work results from an average bioequivalence study between tablets containing 600mg of the antiretroviral efavirenz (EFV), carried out with 14 healthy subjects (8 female and 6 men) in a randomized 2-period, 2-treatment crossover design, are analyzed from a sex-based approach. Sequences were balanced within each sex group. Considering all subjects, no differences were observed on EFV absorbed amount, as shown by the estimated 90CI of the AUC96 Test/Reference bioequivalence ratio (T/R): 0.950-1.05. However, results were not conclusive due to the 90CI for CMAX T/R was 0.743-1.07. Over this parameter, a significant sex-by-formulation interaction was detected: 90CI CMAX T/R was 0.838-1.36 in women and 0.540-0.920 in men; with a 52% relative difference between point estimates. Formulation differences were therefore evidenced only by male subjects. In vitro dissolution and disintegration tests for both products were carried out in two aqueous media: A) SLS 0.25% and B) HCl/KCl pH1.2. T/R results for dissolution efficiency and tablet disintegration times of formulations in both A and B media were highly correlated with CMAX T/R bioequivalence results observed in women and men respectively, showing that a dissimilar gastrointestinal environment between sexes affected EFV oral absorption. This work shows how sex-by-formulation interaction can affect bioequivalence conclusions. Sex effect on product discrimination should be specially disclosed in bioequivalence studies, mainly for drugs aimed to be given to both sexes.

Viral Escape in the Central Nervous System with Multidrug-Resistant Human Immunodeficiency Virus-1

In this study, we report the case of a patient infected with human immunodeficiency virus (HIV)-1 who developed ataxia and neurocognitive impairment due to viral escape within the central nervous system (CNS) with a multidrug-resistant HIV-1 despite long-term viral suppression in plasma. Antiretroviral therapy optimization with drugs with high CNS penetration led to viral suppression in the CSF, regression of ataxia, and improvement of neurocognitive symptoms.

Kinetico-mechanistic studies of substitution reactions on cross-bridged cyclen Co(III) complexes with nucleosides and nucleotides

Kinetico-mechanistic studies on the substitution reactivity of the [Co{(μ-ET)cyclen}(H2O)2](3+) complex cation at pH values within the 6.0-7.0 range with biologically significant ligands have been carried out. The substitution processes have been found to occur exclusively on the mono-hydroxobridged [(Co{(μ-ET)cyclen}(H2O))2(μ-OH)](5+) species formed after equilibration of the cobalt complex in the relevant medium. The studies conducted on the substitution of the aqua/hydroxo ligands of this dinuclear species are indicative of a dominant role of outer-sphere complexation, involving hydrogen-bonding interactions. The values of the outer-sphere complex formation equilibrium constant are in line with the intervention of both the exiting aqua ligands and the NH groups at the encapsulating {(μ-ET)cyclen} ligand. These complexes result in the preferential formation of O- or N-bonded nucleotides depending on the structure of the base moiety of the ligand. Even the entry of the different donor bonded nucleotides is hampered by the hydrogen-bonding interaction with the dangling moiety of an already coordinated ligand. In general the overall substitution processes occur at a faster rate than those published for the fully alkylated encapsulating {(Me)2(μ-ET)cyclen} ligand derivative, as expected for the still available base-catalysing NH groups in the {(μ-ET)cyclen} ligand.

[Soft-tissue infection with Mycobacterium abscessus subsp. abscessus after liposuction and panniculectomy in the Caribbean]

We report the case of a 36-year-old woman who presented with a surgical site infection with atypical mycobacteria several months after liposuction in the Caribbean. Postoperative wound infections with Mycobacterium abscessus present as subcutaneous nodular abscesses with partly putrid secretion. Due to the necessity of specific diagnostic measures, diagnosis is often delayed. Treatment is difficult because Mycobacterium abscessus is resistant to conventional tuberculostatics and many other antibiotics. Clarithromycin combined with amikacin is the commonly used empirical treatment. Treatment duration is several months.

Kinetico-Mechanistic Studies of Nucleoside and Nucleotide Substitution Reactions of Co(III) Complexes of Fully Alkylated Cyclen

The solution chemistry of complex [Co{(Me)2(μ-ET)cyclen}(H2O)2](3+) containing a fully substituted tetraammine ligand designed for the avoidance of base-conjugated substitution mechanisms in the 6-8 pH range has been studied. The study should shed some light on the possible involvement of such Co(III) skeleton in inert interactions with biomolecules. The reactivity and speciation of the complex has been found similar to that of the parent cyclen derivative with the presence of mono- and bis-hydroxo-bridged species; at pH < 7.1, all reactivity has been found to be related to the aqua/hydroxo monomeric complexes. Under these pH conditions, the substitution reactions of the aqua/hydroxo ligands by chloride, inorganic phosphate, thymidine, cytidine 5'-monophosphate (5'-CMP), and thymidine-5'-monophosphate (5'-TMP) have been studied at varying conditions; ionic strength has been kept at 1.0 NaClO4 due to the high concentration of 2-(N-morpholino)ethanesulfonic acid (MES) or N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) used to ensure buffering. Except for chloride, the process occurs neatly in a one or two step process, showing dissociatively activated substitution mechanisms, having in general large ΔH(⧧), positive ΔS(⧧), and values of ΔV(⧧) close to those corresponding to the liberation of an aqua ligand to the reaction medium. The actuation of noticeable encounter-complex formation equilibrium constants has been found to be the determinant for the reactions with nucleosides and nucleotides, a clear indication of the relevance of hydrogen-bonding interactions in the reactivity of these molecules, even in this highly ionic strength medium. For the substitution of the active aqua/hydroxo ligands with 5'-TMP, the first substitution reaction produces an Nthymine-bound 5'-TMP complex that evolves to a bis-5'-TMP with an Nthymine,Ophosphate-bonding structure. The formation of outer-sphere complexes between the dangling phosphate group of the Nthymine-bound 5'-TMP and the thymine moiety of another entering 5'-TMP has been found to be responsible for this fact, which leaves only the phosphate group for coordination available.