Breath tests used to evaluate carbohydrates malabsorption require baseline H
and CH
levels as low as possible. Test cancellation is recommended when exceeding certain cut-offs (H
≥ 20 ppm and CH
≥ ...10 ppm). Although following preparation protocols, many patients have baseline levels above those cut-offs. We investigated if light walking can reduce baseline H
and CH
levels. We retrospectively analyzed baseline H
and CH
levels from 1552 breath tests. Baseline levels (B1), especially in H
, were lower when obtained at later hours of the day. In those with baseline levels above cut-off, re-sampling (B2) after light walking for one hour, decreased H
levels 8 ppm (Q1-Q3: 1-18 ppm), and 2 ppm (Q1-Q3: 0-3 ppm) for CH
. Consequently, 40% of tests with elevated B1 levels, presented B2 levels below mentioned cut-offs. Ten percent of tests considered negative when using B1 for calculations, turned positive when using B2 instead. All positive tests when using B1 values, remained elevated when using B2. Re-sampling after light walking for one hour could allow test performance in those with previous elevated baseline levels, avoiding diagnosis delays. Using the second sample for delta calculations identifies positive patients for malabsorption that would have been considered negative.
Lung cancer is a leading cause of cancer-related death worldwide and in most cases, diagnosis is reached when the tumor has already spread and prognosis is quite poor. For that reason, the research ...for new biomarkers that could improve early diagnosis and its management is essential. Exosomes are microvesicles actively secreted by cells, especially by tumor cells, hauling molecules that mimic molecules of the producing cells. There are multiple methods for exosome isolation and analysis, although not standardized, and cancer exosomes from biological fluids are especially difficult to study. Exosomes’ cargo proteins, RNA, and DNA participate in the communication between cells, favoring lung cancer development by delivering signals for growth, metastasis, epithelial mesenchymal transition, angiogenesis, immunosuppression and even drug resistance. Exosome analysis can be useful as a type of liquid biopsy in the diagnosis, prognosis and follow-up of lung cancer. In this review, we will discuss recent advances in the role of exosomes in lung cancer and their utility as liquid biopsy, with special attention to isolating methods.
Malignant melanoma is an aggressive tumor that produces exosomes, which contain microRNAs (miRNAs) that could be of utility in following tumoral cell dysregulation. MicroR-125b is a miRNA whose ...down-regulation seems to be implicated in melanoma progression.
To analyze miR-125b levels in serum, and in exosomes obtained from serum, from patients with advanced melanoma.
Serum samples were obtained from 21 patients with advanced melanoma, from 16 disease-free patients with melanoma, and from 19 healthy volunteers. Exosomes were isolated from serum by precipitation, and miR-16 and miR-125b levels were quantified by real-time polymerase chain reaction.
MicroR-16, but not miR-125b, was detected in all samples, and miR-16 levels were significantly higher in serum than they were in exosomes. MicroR-16 expression levels did not differ significantly between the 2 groups (patients with melanoma and healthy donors). There was a significant relationship between miR-125b and miR-16 levels in exosomes. Additionally, miR-125b levels in exosomes were significantly lower in patients with melanoma compared with disease-free patients with melanoma and healthy controls.
Exosomes can provide a suitable material to measure circulating miRNA in melanoma, and miR-16 can be used as an endogenous normalizer. Lower levels of miR-125b in exosomes obtained from serum are associated with advanced melanoma disease, probably reflecting the tumoral cell dysregulation.
Some Basic Aspects of HLA-G Biology Alegre, Estibaliz; Rizzo, Roberta; Bortolotti, Daria ...
Journal of immunology research,
01/2014, Letnik:
2014
Journal Article
Recenzirano
Odprti dostop
Human leukocyte antigen-G (HLA-G) is a low polymorphic nonclassical HLA-I molecule restrictively expressed and with suppressive functions. HLA-G gene products are quite complex, with seven HLA-G ...isoforms, four membrane bound, and other three soluble isoforms that can suffer different posttranslational modifications or even complex formations. In addition, HLA-G has been described included in exosomes. In this review we will focus on HLA-G biochemistry with special emphasis to the mechanisms that regulate its expression and how the protein modifications affect the quantification in biological fluids.
The non-classical Human leukocyte antigen G (HLA-G) differs from classical HLA class I molecules by its low genetic diversity, a tissue-restricted expression, the existence of seven isoforms, and ...immuno-inhibitory functions. Most of the known functions of HLA-G concern the membrane-bound HLA-G1 and soluble HLA-G5 isoforms, which present the typical structure of classical HLA class I molecule: a heavy chain of three globular domains α
1
–α
2
–α
3
non-covalently bound to β-2-microglobulin (B2M) and a peptide. Very little is known of the structural features and functions of other HLA-G isoforms or structural conformations other than B2M-associated HLA-G1 and HLA-G5. In the present work, we studied the capability of all isoforms to form homomultimers, and investigated whether they could bind to, and function through, the known HLA-G receptors LILRB1 and LILRB2. We report that all HLA-G isoforms may form homodimers, demonstrating for the first time the existence of HLA-G4 dimers. We also report that the HLA-G α
1
–α
3
structure, which constitutes the extracellular part of HLA-G2 and HLA-G6, binds the LILRB2 receptor but not LILRB1. This is the first report of a receptor for a truncated HLA-G isoform. Following up on this finding, we show that the α
1
–α
3
-Fc structure coated on agarose beads is tolerogenic and capable of prolonging the survival of skin allografts in B6-mice and in a LILRB2-transgenic mouse model. This study is the first proof of concept that truncated HLA-G isoforms could be used as therapeutic agents.
The nonclassical human leukocyte antigen‐G (HLA‐G) is a tolerogenic molecule that can be released to the circulation by expressing cells. This molecule can form dimers but some other complexed HLA‐G ...forms have been proposed to be present in vivo. Here, we further characterized these other complexed HLA‐G forms in vivo. Ascitic and pleural exudates from patients were selected based on positivity for HLA‐G by ELISA. Complexed HLA‐G was detected in exosomes, which indicates an intracellular origin of these forms. 2D‐PAGE analysis of exudates and isolated exosomes showed that these high molecular weight complexes were more heterogeneous than the HLA‐G1 expressed by cell cultures. Treatment with deglycosylating enzymes did not change the molecular weight of HLA‐G complexes. Immunoblot analysis of exudates and exosomes with an anti‐ubiquitin antibody showed that at least some of these structures correspond to ubiquitinated HLA‐G. HLA‐G ubiquitination could be reproduced in vitro in HLA‐G1‐transfected cell lines, although with a lower modified/nonmodified protein proportion than in exudates. In summary, we demonstrate new circulating HLA‐G forms in vivo that open a new perspective in the study of HLA‐G function and analysis.
Variegate porphyria (VP) results from haploinsufficiency of protoporphyrinogen oxidase (PPOX), the seventh enzyme in the heme synthesis pathway. There is no VP model that recapitulates the clinical ...manifestations of acute attacks. Combined administrations of 2-allyl-2-isopropylacetamide and rifampicin in rabbits halved hepatic PPOX activity, resulting in increased accumulation of a potentially neurotoxic heme precursor, lipid peroxidation, inflammation, and hepatocyte cytoplasmic stress. Rabbits also showed hypertension, motor impairment, reduced activity of critical mitochondrial hemoprotein functions, and altered glucose homeostasis. Hemin treatment only resulted in a slight drop in heme precursor accumulation but further increased hepatic heme catabolism, inflammation, and cytoplasmic stress. Hemin replenishment did protect against hypertension, but it failed to restore action potentials in the sciatic nerve or glucose homeostasis. Systemic porphobilinogen deaminase (PBGD) mRNA administration increased hepatic PBGD activity, the third enzyme of the pathway, and rapidly normalized serum and urine porphyrin precursor levels. All features studied were improved, including those related to critical hemoprotein functions. In conclusion, the VP model recapitulates the biochemical characteristics and some clinical manifestations associated with severe acute attacks in humans. Systemic PBGD mRNA provided successful protection against the acute attack, indicating that PBGD, and not PPOX, was the critical enzyme for hepatic heme synthesis in VP rabbits.
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No model recapitulates clinical manifestations of variegate porphyria. Combined administration of 2-allyl-2-isopropylacetamide and rifampicin in rabbits reproduced the biochemical derangements associated with acute attacks, and it induced hypertension and motor impairment. Systemic porphobilinogen deaminase mRNA administration protected from these alterations, thus providing a proof of concept for mRNA-based strategies for the management of variegate porphyria.
Circulating biomarkers in malignant melanoma Alegre, Estibaliz; Sammamed, Miguel; Fernández-Landázuri, Sara ...
Advances in clinical chemistry,
2015, Letnik:
69
Journal Article
Recenzirano
Melanoma is an aggressive tumor with increasing incidence worldwide. Biomarkers are valuable tools to minimize the cost and improve efficacy of treatment of this deadly disease. Serological markers ...have not widely been introduced in routine clinical practice due to their insufficient diagnostic sensitivity and specificity. It is likely that the lack of objective responses with traditional treatment hinder biomarker research and development in melanoma. Recently, new drugs and therapies have, however, emerged in advanced melanoma with noticeable objective response ratio and survival. In this new scenario, serological tumor markers should be revisited. In addition, other potential circulating biomarkers such as cell-free DNA, exosomes, microRNA, and circulating tumor cells have also been identified. In this review, we summarize classical and emerging tumor markers and discuss their possible roles in emerging therapeutics.
Resumen
Objetivos
La malabsorción de lactosa se estudia habitualmente mediante el test de hidrógeno espirado (HBT), aunque su realización no es recomendable cuando la concentración de hidrógeno basal ...(H
2
B) es elevada. Además, la situación actual en relación con el SARS-CoV-2 puede hacer desaconsejable el manejo de muestras de aliento. Objetivo: Evaluar la concordancia del HBT y el test de tolerancia a la lactosa (TTL) en función del H
2
B.
Métodos
Se estudiaron 430 pacientes (40 años, Q1–Q3 = 28–54 años; 66,7% mujeres) con sospecha de malabsorción de lactosa. Se recogieron basalmente y secuencialmente tras la administración de lactosa, muestras de aliento para medir el hidrógeno espirado y de sangre heparinizada para medir la glucemia.
Resultados
El 69,5% de los pacientes tenían H
2
B <10 ppm, el 14,7% valores entre 10 y 20 ppm, y el 15,8% >20 ppm. En los pacientes con H
2
B <20 ppm la concordancia entre el HBT y el TTL era moderada, mejorando siempre al emplear un punto de corte de 15 mg/dL en el TTL. El incremento de hidrógeno y el de glucosa correlacionaron negativamente (r=−0,389; p<0,05). El aumento observado en la glucemia durante el TTL no variaba en función de los niveles de H
2
B registrados en el HBT.
Conclusiónes
El TTL puede ser una alternativa al HBT para evaluar la malabsorción de lactosa cuando los niveles de H
2
B sean elevados o las circunstancias desaconsejen el manejo de muestras de aliento. La mejor concordancia se observa cuando se toma como punto de corte en el TTL de 15 mg/dL.
Lactose malabsorption is generally assessed by hydrogen breath testing (HBT). However, this test is not recommended in patients with high baseline hydrogen concentrations (H
B). In addition, breath ...testing is not recommended in the current situation created by the COVID-19 pandemic, due to the potential infectiveness of the samples. The objective is to assess concordance between HBT and lactose tolerance test (LTT) depending on H
B concentrations.
A total of 430 patients (40 years, Q1-Q3 = 28-54 years; 66.7% women) suspected of lactose malabsorption were included in the study. Breath and heparinized blood samples were collected at baseline and sequentially after the intake of 50 g of lactose, to measure hydrogen in breath and glycemia in blood, respectively.
H
B was <10 ppm in 69.5% of subjects; 10-20 ppm in 14.7%; and >20 ppm in 15.8% of subjects. In patients with H
B <20 ppm, concordance between HBT and LTT was moderate and consistently improved when the cut-off in LTT was set at 15 mg/dL. The increase in hydrogen and glucose correlated negatively (r=-0.389; p<0.05). The increase in glycemia during LTT was not influenced by H
B levels obtained in HBT.
LTT emerges as an alternative to HBT to assess lactose malabsorption in the presence of high H
B levels or when breath testing is not recommended by the circumstances. The best concordance was obtained when the cut-off for LTT was set at 15 mg/dL.
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