Enhanced Membrane Incorporation of H289Y Mutant GluK1 Receptors from the Audiogenic Seizure-Prone GASH/Sal Model: Functional and Morphological Impacts on Xenopus Oocytes.

Epilepsy is a neurological disorder characterized by abnormal neuronal excitability, with glutamate playing a key role as the predominant excitatory neurotransmitter involved in seizures. Animal models of epilepsy are crucial in advancing epilepsy research by faithfully replicating the diverse symptoms of this disorder. In particular, the GASH/Sal (genetically audiogenic seizure-prone hamster from Salamanca) model exhibits seizures resembling human generalized tonic-clonic convulsions. A single nucleotide polymorphism (SNP; C9586732T, p.His289Tyr) in the Grik1 gene (which encodes the kainate receptor GluK1) has been previously identified in this strain. The H289Y mutation affects the amino-terminal domain of GluK1, which is related to the subunit assembly and trafficking. We used confocal microscopy in Xenopus oocytes to investigate how the H289Y mutation, compared to the wild type (WT), affects the expression and cell-surface trafficking of GluK1 receptors. Additionally, we employed the two-electrode voltage-clamp technique to examine the functional effects of the H289Y mutation. Our results indicate that this mutation increases the expression and incorporation of GluK1 receptors into an oocyte's membrane, enhancing kainate-evoked currents, without affecting their functional properties. Although further research is needed to fully understand the molecular mechanisms responsible for this epilepsy, the H289Y mutation in GluK1 may be part of the molecular basis underlying the seizure-prone circuitry in the GASH/Sal model.

A Thermographic Disease Activity Index for remote assessment of rheumatoid arthritis.

OBJECTIVES: Remote assessment of patients with rheumatoid arthritis (RA) has increased during recent years. However, telematic consultations preclude the possibility of carrying out a physical examination and obtaining objective inflammation. In this study, we developed and validated two novel composite disease activity indexes (Thermographic Disease Activity Index (ThermoDAI) and ThermoDAI-CRP) based on thermography of hands and machine learning, in order to assess disease activity easily, rapidly and without formal joint counts. METHODS: ThermoDAI was developed as the sum of Thermographic Joint Inflammation Score (ThermoJIS), a novel joint inflammation score based on the analysis of thermal images of the hands by machine learning, the Patient Global Assessment (PGA) and, for ThermoDAI-CRP, the C reactive protein (CRP). Construct validity was tested in 146 patients with RA by using Spearman's correlation with ultrasound-determined grey-scale synovial hypertrophy (GS) and power Doppler (PD) scores, CDAI, SDAI and DAS28-CRP. RESULTS: Correlations of ultrasound scores with ThermoDAI (GS=0.52; PD=0.56) and ThermoDAI-CRP (GS=0.58; PD=0.61) were moderate to strong, while the correlations of ultrasound scores with PGA (GS=0.35; PD=0.39) and PGA+CRP (GS=0.44; PD=0.46) were weak to moderate. ThermoDAI and ThermoDAI-CRP also showed strong correlations with Clinical Disease Activity Index (ρ>0.83), Simplified Disease Activity Index (ρ>0.85) and Disease Activity Score with 28-Joint Counts-CRP (ρ>0.81) and high sensitivity for detecting active synovitis using remission criteria. CONCLUSIONS: ThermoDAI and ThermoDAI-CRP showed stronger correlations with ultrasound-determined synovitis than PGA and PGA + CRP, thus presenting an opportunity to improve remote consultations with patients with RA.

Xenopus Oocytes as a Powerful Cellular Model to Study Foreign Fully-Processed Membrane Proteins.

The use of Xenopus oocytes in electrophysiological and biophysical research constitutes a long and successful story, providing major advances to the knowledge of the function and modulation of membrane proteins, mostly receptors, ion channels, and transporters. Earlier reports showed that these cells are capable of correctly expressing heterologous proteins after injecting the corresponding mRNA or cDNA. More recently, the Xenopus oocyte has become an outstanding host-cell model to carry out detailed studies on the function of fully-processed foreign membrane proteins after their microtransplantation to the oocyte. This review focused on the latter overall process of transplanting foreign membrane proteins to the oocyte after injecting plasma membranes or purified and reconstituted proteins. This experimental approach allows for the study of both the function of mature proteins, with their native stoichiometry and post-translational modifications, and their putative modulation by surrounding lipids, mostly when the protein is purified and reconstituted in lipid matrices of defined composition. Remarkably, this methodology enables functional microtransplantation to the oocyte of membrane receptors, ion channels, and transporters from different sources including human post-mortem tissue banks. Despite the large progress achieved over the last decades on the structure, function, and modulation of neuroreceptors and ion channels in healthy and pathological tissues, many unanswered questions remain and, most likely, Xenopus oocytes will continue to help provide valuable responses.

Assessment of inflammation in patients with rheumatoid arthritis using thermography and machine learning: a fast and automated technique.

OBJECTIVES: Sensitive detection of joint inflammation in rheumatoid arthritis (RA) is crucial to the success of the treat-to-target strategy. In this study, we characterise a novel machine learning-based computational method to automatically assess joint inflammation in RA using thermography of the hands, a fast and non-invasive imaging technique. METHODS: We recruited 595 patients with arthritis and osteoarthritis, as well as healthy subjects at two hospitals over 4 years. Machine learning was used to assess joint inflammation from the thermal images of the hands using ultrasound as the reference standard, obtaining a Thermographic Joint Inflammation Score (ThermoJIS). The machine learning model was trained and tuned using data from 449 participants with different types of arthritis, osteoarthritis or without rheumatic disease (development set). The performance of the method was evaluated based on 146 patients with RA (validation set) using Spearman's rank correlation coefficient, area under the receiver-operating curve (AUROC), average precision, sensitivity, specificity, positive and negative predictive value and F1-score. RESULTS: ThermoJIS correlated moderately with ultrasound scores (grey-scale synovial hypertrophy=0.49, p<0.001; and power Doppler=0.51, p<0.001). The AUROC for ThermoJIS for detecting active synovitis was 0.78 (95% CI, 0.71 to 0.86; p<0.001). In patients with RA in clinical remission, ThermoJIS values were significantly higher when active synovitis was detected by ultrasound. CONCLUSIONS: ThermoJIS was able to detect joint inflammation in patients with RA, even in those in clinical remission. These results open an opportunity to develop new tools for routine detection of joint inflammation.

Peimine, an Anti-Inflammatory Compound from Chinese Herbal Extracts, Modulates Muscle-Type Nicotinic Receptors.

Fritillaria bulbs are used in Traditional Chinese Medicine to treat several illnesses. Peimine (Pm), an anti-inflammatory compound from Fritillaria, is known to inhibit some voltage-dependent ion channels and muscarinic receptors, but its interaction with ligand-gated ion channels remains unexplored. We have studied if Pm affects nicotinic acetylcholine receptors (nAChRs), since they play broad functional roles, both in the nervous system and non-neuronal tissues. Muscle-type nAChRs were incorporated to Xenopus oocytes and the action of Pm on the membrane currents elicited by ACh (IAChs) was assessed. Functional studies were combined with virtual docking and molecular dynamics assays. Co-application of ACh and Pm reversibly blocked IACh, with an IC50 in the low micromolar range. Pm inhibited nAChR by: (i) open-channel blockade, evidenced by the voltage-dependent inhibition of IAch, (ii) enhancement of nAChR desensitization, revealed by both an accelerated IACh decay and a decelerated IACh deactivation, and (iii) resting-nAChR blockade, deduced from the IACh inhibition elicited by Pm when applied before ACh superfusion. In good concordance, virtual docking and molecular dynamics assays demonstrated that Pm binds to different sites at the nAChR, mostly at the transmembrane domain. Thus, Pm from Fritillaria bulbs, considered therapeutic herbs, targets nAChRs with high affinity, which might account for its anti-inflammatory actions.

Vasculitis reumatoide: estudio de 41 casos / Rheumatoid vasculitis: study of 41 cases

OBJETIVO: Analizar las características clínicas, tratamiento y evolución de la vasculitis reumatoide. MÉTODOS: Estudio retrospectivo (1975-2017). Pacientes con vasculitis reumatoide diagnosticados en 2 servicios de reumatología. RESULTADOS: Se incluyó a 41 pacientes: 17 (41,5%) varones y 24 (58,5%) mujeres; con una edad media al diagnóstico de 67 ± 9 años y una duración de la artritis reumatoide de 10 ± 8,3 años. La artritis fue erosiva en 33 (80%) pacientes. Tanto el factor reumatoide como los anticuerpos antipéptido citrulinados fueron positivos en todos los casos. Los síntomas constitucionales se presentaron en 30 pacientes (73%) y las manifestaciones extrarticulares en 17 (41%). Las manifestaciones clínicas más frecuentes fueron: cutáneas 28 (68%) y neuropatía periférica 26 (63%). Todos los pacientes fueron tratados con glucocorticoides. En 24 pacientes (58%) se asoció a un inmunosupresor y 5 (12%) pacientes fueron tratados con fármacos biológicos. La mortalidad a los 2 años de seguimiento fue del 33%. Las principales causas de muerte fueron: la infección y la progresión de la vasculitis reumatoide. La frecuencia de la vasculitis reumatoide disminuyó en la última década. CONCLUSIONES: Las manifestaciones clínicas de la vasculitis reumatoide en España son similares a las descritas. La frecuencia disminuye; sin embargo, el cuadro clínico y la gravedad se mantienen invariables

AIM: To describe the clinical manifestations, evolution and treatment of patients with rheumatoid vasculitis. METHODS: Retrospective study (1975-2017) of all patients diagnosed with rheumatoid vasculitis in 2 Rheumatology Services. RESULTS: A total of 41 patients were included, 17 (41.5%) males and 24 (58.5%) females; mean age at diagnosis: 67 ± 9 years; duration of rheumatoid arthritis: 10 ± 8.3 years. Most patients had erosive disease, 33 (80%). Rheumatoid factor and anticitrullinated antibodies were positive in all patients. Constitutional symptoms were present in 30 (73%) patients and extra-articular manifestations in 17 (41%) patients. The clinical manifestations of rheumatoid vasculitis were mainly: cutaneous 28 (68%), and polyneuritis 26 (63%). All patients were treated with glucocorticoids. An immunosuppressant was associated in 24 (58.5%) patients. Five (12%) patients were treated with the association of glucocorticoids and a biologic treatment. The mortality after 2years of follow-up was 33%, the most common causes being infection and progression of the vasculitis. The frequency of rheumatoid vasculitis has decreased over the last decade. CONCLUSION: The clinical manifestations of rheumatoid vasculitis were similar to previous studies. The frequency of rheumatoid vasculitis seems to decrease. However, the clinical picture and severity remains invariable

Rheumatoid vasculitis: study of 41 cases. / Vasculitis reumatoide: estudio de 41 casos.

AIM: To describe the clinical manifestations, evolution and treatment of patients with rheumatoid vasculitis. METHODS: Retrospective study (1975-2017) of all patients diagnosed with rheumatoid vasculitis in 2 Rheumatology Services. RESULTS: A total of 41 patients were included, 17 (41.5%) males and 24 (58.5%) females; mean age at diagnosis: 67 ± 9 years; duration of rheumatoid arthritis: 10 ± 8.3 years. Most patients had erosive disease, 33 (80%). Rheumatoid factor and anticitrullinated antibodies were positive in all patients. Constitutional symptoms were present in 30 (73%) patients and extra-articular manifestations in 17 (41%) patients. The clinical manifestations of rheumatoid vasculitis were mainly: cutaneous 28 (68%), and polyneuritis 26 (63%). All patients were treated with glucocorticoids. An immunosuppressant was associated in 24 (58.5%) patients. Five (12%) patients were treated with the association of glucocorticoids and a biologic treatment. The mortality after 2years of follow-up was 33%, the most common causes being infection and progression of the vasculitis. The frequency of rheumatoid vasculitis has decreased over the last decade. CONCLUSION: The clinical manifestations of rheumatoid vasculitis were similar to previous studies. The frequency of rheumatoid vasculitis seems to decrease. However, the clinical picture and severity remains invariable.

Mechanisms of Blockade of the Muscle-Type Nicotinic Receptor by Benzocaine, a Permanently Uncharged Local Anesthetic.

Most local anesthetics (LAs) are amine compounds bearing one or several phenolic rings. Many of them are protonated at physiological pH, but benzocaine (Bzc) is permanently uncharged, which is relevant because the effects of LAs on nicotinic acetylcholine (ACh) receptors (nAChRs) depend on their presence as uncharged or protonated species. The aims of this study were to assess the effects of Bzc on nAChRs and to correlate them with its binding to putative interacting sites on this receptor. nAChRs from Torpedo electroplaques were microtransplanted to Xenopus oocytes and currents elicited by ACh (IAChs), either alone or together with Bzc, were recorded at different potentials. Co-application of ACh with increasing concentrations of Bzc showed that Bzc reversibly blocked nAChRs. IACh inhibition by Bzc was voltage-independent, but the IACh rebound elicited when rinsing Bzc suggests an open-channel blockade. Besides, ACh and Bzc co-application enhanced nAChR desensitization. When Bzc was just pre-applied it also inhibited IACh, by blocking closed (resting) nAChRs. This blockade slowed down the kinetics of both the IACh activation and the recovery from blockade. The electrophysiological results indicate that Bzc effects on nAChRs are similar to those of 2,6-dimethylaniline, an analogue of the hydrophobic moiety of lidocaine. Furthermore, docking assays on models of the nAChR revealed that Bzc and DMA binding sites on nAChRs overlap fairly well. These results demonstrate that Bzc inhibits nAChRs by multiple mechanisms and contribute to better understanding both the modulation of nAChRs and how LAs elicit some of their clinical side effects. This article is part of a Special Issue entitled: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries.

[18F] FDG PET/CT may be a useful adjunct in diagnosis of eosinophilic fasciitis / [18F] FDG PET/CT puede ser un complemento útil en el diagnóstico de fasciitis eosinofílica

No disponible

Dieta mediterránea y artrosis / Mediterranean diet and osteoarthritis

No disponible

Fibroelastosis pleuropulmonar en una paciente con lupus eritematoso sistémico / Pleuropulmonary fibroelastosis in a patient with systemic lupus erythematosus

No disponible

La talalgia en la artropatía psoriásica. Análisis de una serie de 291 pacientes / Heel pain in psoriatic arthropathy: Analysis of a series of 291 patients

Objetivo: Determinar la prevalencia de talalgia clínicamente significativa en una serie de pacientes con artritis psoriásica (APs) y analizar su asociación con otras variables de la enfermedad. Material y métodos: Estudio transversal, observacional, retrospectivo. De la cohorte de 347 pacientes afectos de APs, todos cumplían los criterios de clasificación CASPAR para APs, se seleccionaron 291 en los que estaba recogido el antecedente de talalgia clínicamente significativa. Para el análisis estadístico se ha utilizado la prueba de chi-cuadrado, el ANOVA y la prueba de regresión logística binaria. Resultados: El 35% de los pacientes presentó talalgia clínicamente significativa. La talalgia se asoció significativamente con un inicio más precoz de la enfermedad cutánea y articular, pero no con la duración de la enfermedad. También fue significativa su asociación con la dactilitis y antecedente familiar de primer grado con APs. Conclusiones: La talalgia clínicamente significativa se presentó en un tercio de los pacientes de la serie. Se asoció con dactilitis, antecedente familiar de primer grado con APs y un inicio más precoz de la enfermedad cutánea y articular

Objective: To determine the prevalence of heel pain in a series of patients with psoriatic arthritis (PsA). Material and methods: Cross-sectional, observational and retrospective study of a series of 347 patients. All patients fulfilled the CASPAR criteria for PsA and 291 had a clinically significant history of heel pain. The statistical analysis was performed using chi-square test, ANOVA and binary logistic regression. Results: Thirty-five percent of the patients had clinically significant heel pain. A significant association was established between an early onset of skin and joint involvement in the disease and the development of heel pain. However, no significant correlation was found between disease duration and the presence of heel pain. History of dactylitis and PsA in first-degree family members was also statistically associated with this complication. Conclusions: Clinically significant heel pain was recorded in one third of the patients in this series. There was a statistically significant association with dactylitis, PsA in first-degree family members and an earlier onset of joint and skin disease

Osteoarthritis and the Mediterranean Diet: A Systematic Review.

Osteoarthritis (OA) affects 240 million people globally. Few studies have examined the links between osteoarthritis and the Mediterranean diet (MD). The aim of this paper was to systematically review and analyze the epidemiological evidence in humans on the MD and its association with OA. A systematic search of EMBASE identified three studies that explored the association between MD and OA. Two of them were cross-sectional and the third one was a 16-week randomized clinical trial. Prisma declaration was followed to carry out this review. These studies described a positive association between a higher adherence to a MD and the quality of life of participants suffering OA. The prevalence of OA was lower in participants with a higher adherence to a Mediterranean diet. Biomarkers of inflammation and cartilage degradation related to OA were also analyzed and significant differences were detected only for IL1-α, which decreased in the MD group. Exploring the relationship between MD and OA is complex, moreover, the limited evidence and methodological differences in such studies makes it difficult to compare results. In conclusion, the three studies included in this systematic review demonstrated some relation between osteoarthritis and a Mediterranean diet. However, prospective and longer interventions are required to evaluate the long-term efficacy of the Mediterranean diet to improve symptomatology and preventing osteoarthritis.

Mechanisms Underlying the Strong Inhibition of Muscle-Type Nicotinic Receptors by Tetracaine.

Nicotinic acetylcholine (ACh) receptors (nAChRs) are included among the targets of a variety of local anesthetics, although the molecular mechanisms of blockade are still poorly understood. Some local anesthetics, such as lidocaine, act on nAChRs by different means through their ability to present as both charged and uncharged molecules. Thus, we explored the mechanisms of nAChR blockade by tetracaine, which at physiological pH is almost exclusively present as a positively charged local anesthetic. The nAChRs from Torpedo electroplaques were transplanted to Xenopus oocytes and the currents elicited by ACh (IACh s), either alone or co-applied with tetracaine, were recorded. Tetracaine reversibly blocked IACh , with an IC50 (i.e., the concentration required to inhibit half the maximum IACh ) in the submicromolar range. Notably, at very low concentrations (0.1 µM), tetracaine reduced IACh in a voltage-dependent manner, the more negative potentials produced greater inhibition, indicating open-channel blockade. When the tetracaine concentration was increased to 0.7 µM or above, voltage-independent inhibition was also observed, indicating closed-channel blockade. The IACh inhibition by pre-application of just 0.7 µM tetracaine before superfusion of ACh also corroborated the notion of tetracaine blockade of resting nAChRs. Furthermore, tetracaine markedly increased nAChR desensitization, mainly at concentrations equal or higher than 0.5 µM. Interestingly, tetracaine did not modify desensitization when its binding within the channel pore was prevented by holding the membrane at positive potentials. Tetracaine-nAChR interactions were assessed by virtual docking assays, using nAChR models in the closed and open states. These assays revealed that tetracaine binds at different sites of the nAChR located at the extracellular and transmembrane domains, in both open and closed conformations. Extracellular binding sites seem to be associated with closed-channel blockade; whereas two sites within the pore, with different affinities for tetracaine, contribute to open-channel blockade and the enhancement of desensitization, respectively. These results demonstrate a concentration-dependent heterogeneity of tetracaine actions on nAChRs, and contribute to a better understanding of the complex modulation of muscle-type nAChRs by local anesthetics. Furthermore, the combination of functional and virtual assays to decipher nAChR-tetracaine interactions has allowed us to tentatively assign the main nAChR residues involved in these modulating actions.

Heel pain in psoriatic arthropathy: Analysis of a series of 291 patients. / La talalgia en la artropatía psoriásica. Análisis de una serie de 291 pacientes.

OBJECTIVE: To determine the prevalence of heel pain in a series of patients with psoriatic arthritis (PsA). MATERIAL AND METHODS: Cross-sectional, observational and retrospective study of a series of 347 patients. All patients fulfilled the CASPAR criteria for PsA and 291 had a clinically significant history of heel pain. The statistical analysis was performed using chi-square test, ANOVA and binary logistic regression. RESULTS: Thirty-five percent of the patients had clinically significant heel pain. A significant association was established between an early onset of skin and joint involvement in the disease and the development of heel pain. However, no significant correlation was found between disease duration and the presence of heel pain. History of dactylitis and PsA in first-degree family members was also statistically associated with this complication. CONCLUSIONS: Clinically significant heel pain was recorded in one third of the patients in this series. There was a statistically significant association with dactylitis, PsA in first-degree family members and an earlier onset of joint and skin disease.

Adult-onset Still's disease with atypical cutaneous manifestations.

The diagnosis of adult-onset Still's disease (AOSD) can be very difficult. There are no specific tests available, and diagnosis is usually based on a symptom complex and the well-described typical evanescent rash seen in the majority of patients. However, in recent years, other atypical cutaneous manifestations of AOSD have been reported. These atypical skin eruptions often present in addition to the typical evanescent rash but may also be the only skin manifestation, resulting in delayed diagnosis because of under-recognition.In this study, we present 3 new cases of AOSD with atypical cutaneous manifestations diagnosed during a 30-year period in our department and review 78 additional cases previously reported (PubMed 1990-2016). These 81 patients form the basis of the present analysis.The overall prevalence of atypical cutaneous manifestations in our AOSD population was 14%. These manifestations may appear at any time over the course of the disease, and usually occur in patients who have persistent and severe disease, with a considerable frequency of clinical complications (23%), including serositis, myopericarditis, lung involvement, abdominal pain, neurologic involvement, and reactive hemophagocytic syndrome.The most representative and frequent lesion among the nonclassical skin rashes is the development of persistent pruritic papules and/or plaques. Interestingly, these lesions show a distinctive histological pattern. Other, less frequently observed lesions include urticaria and urticaria-like eruptions, generalized or widespread non-pruritic persistent erythema, vesiculopustular eruptions, a widespread peau d'orange appearance of the skin, and edema of the eyelids mimicking dermatomyositis without any accompanying skin lesion.The great majority of these patients required medium or high doses of glucocorticoids (including intravenous methylprednisolone pulse therapy in some cases) and, in nearly 40%, a more potent or maintenance immunotherapy with immunosuppressant drugs and/or biologic agents (mainly anakinra or tocilizumab) to control or manage symptoms because of a polycyclic or chronic course. The development of atypical cutaneous manifestations seems to be associated with a potentially worse prognosis, with a mortality rate reaching 8% primarily because of infectious complications related to immunosuppressive therapy.In conclusion, the appearance of atypical cutaneous manifestations is not uncommon in AOSD. Recognition of this clinical variant is crucial for the early diagnosis of AOSD, as it might imply persistent disease activity and the need for more aggressive treatment.