Unraveling the Mechanisms Behind Exercise Intolerance and Recovery in Long COVID.

BACKGROUND: Patients suffering from long COVID may exhibit autonomic dysregulation. However, the association between autonomic dysregulation and exercise intolerance and the impact of therapeutic interventions on its modulation remains unclear. This study investigated the relationship between heart rate recovery at the first minute (HRR1), a proxy for autonomic imbalance, and exercise intolerance in patients with long COVID. Additionally, the study aimed to assess the effects of a 12-week home-based inspiratory muscle training program on autonomic modulation in this patient population. METHODS: This study is a post hoc subanalysis of a randomized trial in which 26 patients with long COVID were randomly assigned to receive either a 12-week inspiratory muscle training program or usual care alone (NCT05279430). The data were analyzed using Pearson's correlation and linear mixed regression analysis. RESULTS: The mean age was 50.4 ± 12.2 years, and 11 (42.3%) were women. Baseline HRR1 was significantly correlated with maximal functional capacity (peakVO2) (r = 0.402, P = .041). Patients with lower baseline HRR1 (≤22 bpm) exhibited higher resting heart rates and lower peakVO2. Inspiratory muscle training led to a more substantial increase in peakVO2 in patients with lower HRR1 at baseline (P = .019). Additionally, a significant improvement in HRR1 was observed in the IMT group compared to the usual care group after 12-week (Δ +9.39, 95% CI = 2.4-16.4, P = .010). CONCLUSION: Lower baseline HRR1 is associated with exercise intolerance in long COVID patients and may serve as a valuable criterion for identifying individuals likely to benefit more from a home-based inspiratory muscle training program.

The promise of genetic screens in human in vitro brain models.

Advances of in vitro culture models have allowed unprecedented insights into human neurobiology. At the same time genetic screening has matured into a robust and accessible experimental strategy allowing for the simultaneous study of many genes in parallel. The combination of both technologies is a newly emerging tool for neuroscientists, opening the door to identifying causal cell- and tissue-specific developmental and disease mechanisms. However, with complex experimental genetic screening set-ups new challenges in data interpretation and experimental scope arise that require a deep understanding of the benefits and challenges of individual approaches. In this review, we summarize the literature that applies genetic screening to in vitro brain models, compare experimental strengths and weaknesses and point towards future directions of these promising approaches.

Feasibility of an online antigen self-testing strategy for SARS-CoV-2 addressed to health care and education professionals in Catalonia (Spain). The TESTA'T- COVID Project.

We aimed to assess the feasibility of TESTA'T COVID strategy among healthcare and education professionals.in Spain during the peak of the 6th wave caused by Omicron variant. Kits were ordered online and sent by mail, participants answered an online acceptability/usability survey and uploaded the picture of results. 492 participants ordered a test, 304 uploaded the picture (61.8%). Eighteen positive cases were detected (5.9%). 92.2% were satisfied/very satisfied with the intervention; and 92.5% found performing the test easy/very easy. We demonstrated that implementing online COVID-19 self-testing in schools and healthcare settings in Spain is feasible.

Persistently positive PCR SARS-CoV-2 at low cycle threshold in an immunosuppressed patient.

We describe the very prolonged course of the disease in an immunosuppressed patient with persistently positive PCR against SARS-CoV-2 with low cycle threshold for at least 114 days.

Persistently positive PCR SARS-CoV-2 at low cycle threshold in an immunosuppressed patient

ABSTRACT We describe the very prolonged course of the disease in an immunosuppressed patient with persistently positive PCR against SARS-CoV-2 with low cycle threshold for at least 114 days.

Olive oil-derived nitro-fatty acids: protection of mitochondrial function in non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive liver fat deposition in the absence of significant alcohol intake. Since extra virgin olive oil (EVOO) reduces fat accumulation, we analyzed the involvement of nitro-fatty acids (NO2-FA) on the beneficial effects of EVOO consumption on NAFLD. Nitro-fatty acids formation was observed during digestion in mice supplemented with EVOO and nitrite. Mice fed with a high-fat diet (HF) presented lower plasma NO2-FA levels than normal chow, and circulating concentrations recovered when the HF diet was supplemented with 10% EVOO plus nitrite. Under NO2-FA formation conditions, liver hemoxygenase-1 expression significantly increased while decreased body weight and fat liver accumulation. Mitochondrial dysfunction plays a central role in the pathogenesis of NAFLD while NO2-FA has been shown to protect from mitochondrial oxidative damage. Accordingly, an improvement of respiratory indexes was observed when mice were supplemented with both EVOO plus nitrite. Liver mitochondrial complexes II and V activities were greater in mice with EVOO supplementation and further improved in the presence of nitrite. Overall, our results strongly suggest a positive correlation between NO2-OA formation from EVOO and the observed improvement of mitochondrial function in NAFLD. The formation of NO2-FA can account for the health benefits associated with EVOO consumption.

Recurrent Vertebrobasilar Strokes Associated With Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE).

INTRODUCTION: Acute posterior multifocal placoid pigment epitheliopathy (APMPPE) is an ophthalmologic condition of likely immune origin. Typically, it presents as a chorioretinitis with bilateral visual disturbance and characteristic funduscopic lesions of the retinal pigment epithelium. APMPPE has been associated with several systemic and neurological complications, including cerebrovascular diseases. CASE REPORT: A 58-year-old woman presented with sudden right hemiparesis and dysarthria, with magnetic resonance imaging evidence of an acute ischemic lesion in the left pons. Five days later, she developed contralateral hemiparesis and evolved into a locked-in syndrome. A new lesion located at the right pontomedullary junction was detected by magnetic resonance imaging. The patient developed a visual deterioration that had started 1 week before admission. An ophthalmologic evaluation showed visual acuity loss (20/200 in both eyes) and characteristic yellow-white lesions in the posterior pole of both eyes. Laboratory analyses were remarkable for positive antinuclear antibodies, an elevated erythrocyte sedimentation rate, and C-reactive protein. The cerebrospinal fluid showed elevated protein levels, lymphocytic pleocytosis, and normal glucose levels. The fundoscopy findings together with recurrent strokes led to the diagnosis of APMPPE and appropriate immunomodulatory treatment with corticosteroids and azathioprine was started. CONCLUSIONS: This case illustrates the importance of careful evaluation and high clinical suspicion for this entity when dealing with patients with new-onset headache or stroke associated with visual impairment. Proper ophthalmologic evaluation is important so that adequate therapy is established.

Endogenous Biosynthesis of S-Nitrosoglutathione From Nitro-Fatty Acids in Plants.

Nitro-fatty acids (NO2-FAs) are novel molecules resulting from the interaction of unsaturated fatty acids and nitric oxide (NO) or NO-related molecules. In plants, it has recently been described that NO2-FAs trigger an antioxidant and a defence response against stressful situations. Among the properties of NO2-FAs highlight the ability to release NO therefore modulating specific protein targets through post-translational modifications (NO-PTMs). Thus, based on the capacity of NO2-FAs to act as physiological NO donors and using high-accuracy mass-spectrometric approaches, herein, we show that endogenous nitro-linolenic acid (NO2-Ln) can modulate S-nitrosoglutathione (GSNO) biosynthesis in Arabidopsis. The incubation of NO2-Ln with GSH was analyzed by LC-MS/MS and the in vitro synthesis of GSNO was noted. The in vivo confirmation of this behavior was carried out by incubating Arabidopsis plants with 15N-labeled NO2-Ln throughout the roots, and 15N-labeled GSNO (GS15NO) was detected in the leaves. With the aim to go in depth in the relation of NO2-FA and GSNO in plants, Arabidopsis alkenal reductase mutants (aer mutants) which modulate NO2-FAs levels were used. Our results constitute the first evidence of the modulation of a key NO biological reservoir in plants (GSNO) by these novel NO2-FAs, increasing knowledge about S-nitrosothiols and GSNO-signaling pathways in plants.

Encapsulation of probiotics in soybean protein-based microparticles preserves viable cell concentration in foods all along the production and storage processes.

The influence on the stability of Lactobacillus plantarum CECT 220 (25 °C/60% relative humidity) of microencapsulation by simple coacervation followed by spray-drying using different Ca2+-to-soybean protein isolate ratios was evaluated. After optimisation, the selected soybean protein concentrate (SPC) microparticles were used to evaluate the tolerance of L. plantarum under acidic conditions (lactic acid, pH = 4; and HCl, pH = 3) and heat stress (80 °C for 1 min) in contrast to free cells. Moreover, after the heat treatment, the influence of the simulated gastric fluid was evaluated. Additionally, different foods were formulated using either microencapsulated or freeze-dried L. plantarum, and the stability of cells during the shelf-life of the formulated foods was studied. Results show that encapsulation with SPC enhanced significantly the stability of the Lactic Acid Bacteria all along the probiotic food value chain, from production to the end of the food shelf-life.

Short-Term Low Temperature Induces Nitro-Oxidative Stress that Deregulates the NADP-Malic Enzyme Function by Tyrosine Nitration in Arabidopsis thaliana.

Low temperature (LT) negatively affects plant growth and development via the alteration of the metabolism of reactive oxygen and nitrogen species (ROS and RNS). Among RNS, tyrosine nitration, the addition of an NO2 group to a tyrosine residue, can modulate reduced nicotinamide-dinucleotide phosphate (NADPH)-generating systems and, therefore, can alter the levels of NADPH, a key cofactor in cellular redox homeostasis. NADPH also acts as an indispensable electron donor within a wide range of enzymatic reactions, biosynthetic pathways, and detoxification processes, which could affect plant viability. To extend our knowledge about the regulation of this key cofactor by this nitric oxide (NO)-related post-translational modification, we analyzed the effect of tyrosine nitration on another NADPH-generating enzyme, the NADP-malic enzyme (NADP-ME), under LT stress. In Arabidopsis thaliana seedlings exposed to short-term LT (4 °C for 48 h), a 50% growth reduction accompanied by an increase in the content of superoxide, nitric oxide, and peroxynitrite, in addition to diminished cytosolic NADP-ME activity, were found. In vitro assays confirmed that peroxynitrite inhibits cytosolic NADP-ME2 activity due to tyrosine nitration. The mass spectrometric analysis of nitrated NADP-ME2 enabled us to determine that Tyr-73 was exclusively nitrated to 3-nitrotyrosine by peroxynitrite. The in silico analysis of the Arabidopsis NADP-ME2 protein sequence suggests that Tyr73 nitration could disrupt the interactions between the specific amino acids responsible for protein structure stability. In conclusion, the present data show that short-term LT stress affects the metabolism of ROS and RNS, which appears to negatively modulate the activity of cytosolic NADP-ME through the tyrosine nitration process.

Post-Translational Modification of Proteins Mediated by Nitro-Fatty Acids in Plants: Nitroalkylation.

Nitrate fatty acids (NO2-FAs) are considered reactive lipid species derived from the non-enzymatic oxidation of polyunsaturated fatty acids by nitric oxide (NO) and related species. Nitrate fatty acids are powerful biological electrophiles which can react with biological nucleophiles such as glutathione and certain protein⁻amino acid residues. The adduction of NO2-FAs to protein targets generates a reversible post-translational modification called nitroalkylation. In different animal and human systems, NO2-FAs, such as nitro-oleic acid (NO2-OA) and conjugated nitro-linoleic acid (NO2-cLA), have cytoprotective and anti-inflammatory influences in a broad spectrum of pathologies by modulating various intracellular pathways. However, little knowledge on these molecules in the plant kingdom exists. The presence of NO2-OA and NO2-cLA in olives and extra-virgin olive oil and nitro-linolenic acid (NO2-Ln) in Arabidopsis thaliana has recently been detected. Specifically, NO2-Ln acts as a signaling molecule during seed and plant progression and beneath abiotic stress events. It can also release NO and modulate the expression of genes associated with antioxidant responses. Nevertheless, the repercussions of nitroalkylation on plant proteins are still poorly known. In this review, we demonstrate the existence of endogenous nitroalkylation and its effect on the in vitro activity of the antioxidant protein ascorbate peroxidase.

Comparative study of the strongest solid Lewis acids known: ACF and HS-AlF3.

Aluminium chlorofluoride (ACF) and high-surface aluminium fluoride (HS-AlF3) were analyzed by a set of characterization methods to assess their acidic properties: NH3-TPD, CO adsorption followed by DRIFTS, CD3CN-PAS-FTIR and MAS NMR spectroscopy after 15N-pyridine adsorption. Both catalysts contain very strong and medium-strong Lewis acid sites as confirmed by CO adsorption, in which small differences arise from the morphological properties of each catalyst, with ACF being microporous and HS-AlF3 mesoporous. Shifts of the CO vibration band of up to 77 cm-1 were observed, which account for very strong Lewis acid sites. In addition, very strong Lewis acid sites could be identified by CD3CN-PAS for both catalysts, exhibiting a shift of 95 cm-1 from free nitrile, the highest ever reported for a solid Lewis acid.

Nitric oxide buffering and conditional nitric oxide release in stress response.

Nitric oxide (NO) has emerged as an essential biological messenger in plant biology that usually transmits its bioactivity by post-translational modifications such as S-nitrosylation, the reversible addition of an NO group to a protein cysteine residue leading to S-nitrosothiols (SNOs). In recent years, SNOs have risen as key signalling molecules mainly involved in plant response to stress. Chief among SNOs is S-nitrosoglutathione (GSNO), generated by S-nitrosylation of the key antioxidant glutathione (GSH). GSNO is considered the major NO reservoir and a phloem mobile signal that confers to NO the capacity to be a long-distance signalling molecule. GSNO is able to regulate protein function and gene expression, resulting in a key role for GSNO in fundamental processes in plants, such as development and response to a wide range of environmental stresses. In addition, GSNO is also able to regulate the total SNO pool and, consequently, it could be considered the storage of NO in cells that may control NO signalling under basal and stress-related responses. Thus, GSNO function could be crucial during plant response to environmental stresses. Besides the importance of GSNO in plant biology, its mode of action has not been widely discussed in the literature. In this review, we will first discuss the GSNO turnover in cells and secondly the role of GSNO as a mediator of physiological and stress-related processes in plants, highlighting those aspects for which there is still some controversy.

Biological properties of nitro-fatty acids in plants.

Nitro-fatty acids (NO2-FAs) are formed from the reaction between nitrogen dioxide (NO2) and mono and polyunsaturated fatty acids. Knowledge concerning NO2-FAs has significantly increased within a few years ago and the beneficial actions of these species uncovered in animal systems have led to consider them as molecules with therapeutic potential. Based on their nature and structure, NO2-FAs have the ability to release nitric oxide (NO) in aqueous environments and the capacity to mediate post-translational modifications (PTM) by nitroalkylation. Recently, based on the potential of these NO-derived molecules in the animal field, the endogenous occurrence of nitrated-derivatives of linolenic acid (NO2-Ln) was assessed in plant species. Moreover and through RNA-seq technology, it was shown that NO2-Ln can induce a large set of heat-shock proteins (HSPs) and different antioxidant systems suggesting this molecule may launch antioxidant and defence responses in plants. Furthermore, the capacity of this nitro-fatty acid to release NO has also been demonstrated. In view of this background, here we offer an overview on the biological properties described for NO2-FAs in plants and the potential of these molecules to be considered new key intermediaries of NO metabolism in the plant field.

Identification of Tyrosine and Nitrotyrosine with a Mixed-Mode Solid-Phase Extraction Cleanup Followed by Liquid Chromatography-Electrospray Time-of-Flight Mass Spectrometry in Plants.

In higher plants, there is a growing interest in the study of protein tyrosine nitration (NO2Tyr) as well as the identification of in vivo nitrated proteins. Different methods have been developed for identifying nitrotyrosine in biological samples. However, these analyses are difficult because tyrosine nitration is a very low-abundance posttranslational protein modification (PTM) and the lack of efficient enrichment methods for detection. The identification and quantification of NO2Tyr in proteins has represented a challenge for researchers.In this chapter a new method for determining NO2Tyr and tyrosine (Tyr) in Arabidopsis thaliana cell-suspension culture extracts is proposed. The quantification was performed using a simple, sensitive, and specific sample preparation assay based on mixed-mode solid-phase extraction (SPE) which was developed for the quantification of trace NO2Tyr in Arabidopsis extracts by liquid chromatography-electrospray time-of-flight mass spectrometry (LC-TOFMS).

Nitro-Fatty Acid Detection in Plants by High-Pressure Liquid Chromatography Coupled to Triple Quadrupole Mass Spectrometry.

In the last few years, the role of nitric oxide (NO) and NO-related molecules has attracted attention in the field of plant systems. In this sense, the ability of NO to mediate several posttranslational modifications (NO-PTM) in different biomolecules, such as protein tyrosine nitration or S-nitrosylation, has shown the involvement of these reactive nitrogen species in a wide range of functions in plant physiology such as the antioxidant response or the involvement in processes such as germination, growth, development, or senescence. However, growing interest has focused on the interaction of these NO-derived molecules with unsaturated fatty acids, yielding nitro-fatty acids (NO2-FAs). It has recently been shown that these molecules are involved in key signaling pathways in animal systems through the implementation of antioxidant and anti-inflammatory responses. Nevertheless, this interaction has been poorly studied in plant systems. Very recently, the endogenous presence of NO2-FAs in the model plant Arabidopsis thaliana has been demonstrated as well as the significant involvement of nitro-linolenic acid (NO2-Ln) in the defence response against several abiotic and oxidative stress conditions. In this respect, the detection of NO2-FAs in plant systems can be a useful tool to determine the importance of these molecules in the regulation of different biochemical pathways. Using high-pressure liquid chromatography coupled to triple quadrupole mass spectrometry (LC-MS/MS), the methods described in this chapter enable the determination of the NO2-FA content in a pM range as well as the characterization of these nitrated derivatives of unsaturated fatty acids in plant tissues.

Cervical cancer screening cotesting with cytology and MRNA HPV E6/E7 yields high rates of CIN2+ lesions in young women.

BACKGROUND: European guidelines recommend primary HPV testing for cervical cancer screening. However, the starting age remains to be defined, with an undecided window between 30 and 35 years. This pilot study compares the effectiveness of primary HPV testing to that of cytology for the detection of high-grade (CIN2+) lesions stratified by age. METHODS: Cotesting with LBC cytology and APTIMA® HPV (AHPV) was performed in 5053 women aged 25-65 in an opportunistic screening program in Madrid. AHPV-positive cases were referred to colposcopy and genotyped for HPV16 and 18/45 (AHPV-GT). Results were analyzed stratified in four age groups. RESULTS: 454 cases (9.0%) were AHPV-positive. Women under 35 had a 30.2% CIN2+ rate, compared to 21.9% and 20.4% for women aged 35-44 or 45-54. There was a significant increase (P < .05) in the rate of CIN2+ in AHPV-GT-positive women when compared to that for other HPV types (AHPV-other), being 43.3% versus 15.7%. AHPV-GT-positive women under 35 had significantly higher rates of CIN2+ lesions than any other age-group. The sensitivity of cytology for cervical CIN2+ in APHV-positive women was 60.6%. All 4 carcinomas, including one AHPV-negative endometrial adenocarcinoma, had abnormal cytology. All cervical CIN2+ lesions biopsied were AHPV-positive. CONCLUSIONS: Aptima HPV shows a significantly higher sensitivity for cervical CIN2+ lesions than cytology alone. Unexpectedly, AHPV-positive women under 35 had the highest incidence of CIN2+ lesions, particularly when they are HPV16/18/45-positive. Reconsidering HPV primary screening before the recommended age of 35 is warranted.

Nitro-fatty acids in plant signaling: New key mediators of nitric oxide metabolism.

Recent studies in animal systems have shown that NO can interact with fatty acids to generate nitro-fatty acids (NO2-FAs). They are the product of the reaction between reactive nitrogen species and unsaturated fatty acids, and are considered novel mediators of cell signaling based mainly on a proven anti-inflammatory response. Although these signaling mediators have been described widely in animal systems, NO2-FAs have scarcely been studied in plants. Preliminary data have revealed the endogenous presence of free and protein-adducted NO2-FAs in extra-virgin olive oil (EVOO), which appear to be contributing to the cardiovascular benefits associated with the Mediterranean diet. Importantly, new findings have displayed the endogenous occurrence of nitro-linolenic acid (NO2-Ln) in the model plant Arabidopsis thaliana and the modulation of NO2-Ln levels throughout this plant's development. Furthermore, a transcriptomic analysis by RNA-seq technology established a clear signaling role for this molecule, demonstrating that NO2-Ln was involved in plant-defense response against different abiotic-stress conditions, mainly by inducing the chaperone network and supporting a conserved mechanism of action in both animal and plant defense processes. Thus, NO2-Ln levels significantly rose under several abiotic-stress conditions, highlighting the strong signaling role of these molecules in the plant-protection mechanism. Finally, the potential of NO2-Ln as a NO donor has recently been described both in vitro and in vivo. Jointly, this ability gives NO2-Ln the potential to act as a signaling molecule by the direct release of NO, due to its capacity to induce different changes mediated by NO or NO-related molecules such as nitration and S-nitrosylation, or by the electrophilic capacity of these molecules through a nitroalkylation mechanism. Here, we describe the current state of the art regarding the advances performed in the field of NO2-FAs in plants and their implication in plant physiology.

Protein Tyrosine Nitration during Development and Abiotic Stress Response in Plants.

In recent years, the study of nitric oxide (NO) in plant systems has attracted the attention of many researchers. A growing number of investigations have shown the significance of NO as a signal molecule or as a molecule involved in the response against (a)biotic processes. NO can be responsible of the post-translational modifications (NO-PTM) of target proteins by mechanisms such as the nitration of tyrosine residues. The study of protein tyrosine nitration during development and under biotic and adverse environmental conditions has increased in the last decade; nevertheless, there is also an endogenous nitration which seems to have regulatory functions. Moreover, the advance in proteome techniques has enabled the identification of new nitrated proteins, showing the high variability among plant organs, development stage and species. Finally, it may be important to discern between a widespread protein nitration because of greater RNS content, and the specific nitration of key targets which could affect cell-signaling processes. In view of the above point, we present a mini-review that offers an update about the endogenous protein tyrosine nitration, during plant development and under several abiotic stress conditions.