Effect of Prewarming on Perioperative Hypothermia in Patients Undergoing Loco-Regional or General Anesthesia: A Randomized Clinical Trial.

Background and Objectives: Redistribution hypothermia occurs during anesthesia despite active intraoperative warming. Prewarming increases the heat absorption by peripheral tissue, reducing the central to peripheral heat gradient. Therefore, the addition of prewarming may offer a greater preservation of intraoperative normothermia as compared to intraoperative warming only. Materials and Methods: A single-center clinical trial of adults scheduled for non-cardiac surgery. Patients were randomized to receive or not a prewarming period (at least 10 min) with convective air devices. Intraoperative temperature management was identical in both groups and performed according to a local protocol. The primary endpoint was the incidence, the magnitude and the duration of hypothermia (according to surgical time) between anesthetic induction and arrival at the recovery room. Secondary outcomes were core temperature on arrival in operating room, surgical site infections, blood losses, transfusions, patient discomfort (i.e., shivering), reintervention and hospital stay. Results: In total, 197 patients were analyzed: 104 in the control group and 93 in the prewarming group. Core temperature during the intra-operative period was similar between groups (p = 0.45). Median prewarming lasted 27 (17-38) min. Regarding hypothermia, we found no differences in incidence (controls: 33.7%, prewarming: 39.8%; p = 0.37), duration (controls: 41.6% (17.8-78.1), prewarming: 45.2% (20.6-71.1); p = 0.83) and magnitude (controls: 0.19 °C · h-1 (0.09-0.54), prewarming: 0.20 °C · h-1 (0.05-0.70); p = 0.91). Preoperative thermal discomfort was more frequent in the prewarming group (15.1% vs. 0%; p < 0.01). The interruption of intraoperative warming was more common in the prewarming group (16.1% vs. 6.7%; p = 0.03), but no differences were seen in other secondary endpoints. Conclusions: A preoperative prewarming period does not reduce the incidence, duration and magnitude of intraoperative hypothermia. These results should be interpreted considering a strict protocol for perioperative temperature management and the low incidence of hypothermia in controls.

Tracheostomy in patients with SARS-CoV-2 reduces time on mechanical ventilation but not intensive care unit stay.

Cross-sectional study to know if tracheostomy influences the time on mechanical ventilation and reduces the ICU stay in patients with SARS-CoV2. From February 14 to May 31, 2020, 29 patients: 23 men and 6 women, with an average age (SD) of 66.4 years (±6,2) required tracheostomy. The average intensive care unit (ICU) stay was 36 days [31-56.5]. The average days on mechanical ventilation was 28,5 days (±9.7). Mean time to tracheostomy was 15.2 days (±9.5) with an average disconnection time after procedure of 11.3 days (±7.4). The average hospital stay was 55 days [39-79]. A directly proportional relation between the number of days of MV and the number of days from ICU admission until tracheostomy showed a significant value of p = 0.008. For each day of delay in tracheostomy, the days of mechanical ventilation were increased by 0.6 days. There was no relation between days to tracheostomy and days to disconnection (p = 0.092). PaO2 / FiO2 (PAFI) before tracheostomy and Simplified Acute Physiology Score III (SAPS III) at admission presented a statistical relation with mortality, with an OR of 1.683 (95%CI; 0.926-2.351; p = 0.078) and an OR of 1.312 (CI95%: 1.011-1.703; p = 0.034) respectively. The length of stay in the ICU until the tracheostomy was not related to the risk of death (p = 0.682). PEEP and PaO2/FiO2 (PAFI) at admission and before tracheostomy and APACHE II, SAPS III and SOFA at admission did not show influence over time on MV. We conclude that the delay in tracheostomy increase the days on mechanical ventilation but does not influence stay or mortality.

Machine learning based study for the classification of Type 2 diabetes mellitus subtypes.

PURPOSE: Data-driven diabetes research has increased its interest in exploring the heterogeneity of the disease, aiming to support in the development of more specific prognoses and treatments within the so-called precision medicine. Recently, one of these studies found five diabetes subgroups with varying risks of complications and treatment responses. Here, we tackle the development and assessment of different models for classifying Type 2 Diabetes (T2DM) subtypes through machine learning approaches, with the aim of providing a performance comparison and new insights on the matter. METHODS: We developed a three-stage methodology starting with the preprocessing of public databases NHANES (USA) and ENSANUT (Mexico) to construct a dataset with N = 10,077 adult diabetes patient records. We used N = 2,768 records for training/validation of models and left the remaining (N = 7,309) for testing. In the second stage, groups of observations -each one representing a T2DM subtype- were identified. We tested different clustering techniques and strategies and validated them by using internal and external clustering indices; obtaining two annotated datasets Dset A and Dset B. In the third stage, we developed different classification models assaying four algorithms, seven input-data schemes, and two validation settings on each annotated dataset. We also tested the obtained models using a majority-vote approach for classifying unseen patient records in the hold-out dataset. RESULTS: From the independently obtained bootstrap validation for Dset A and Dset B, mean accuracies across all seven data schemes were [Formula: see text] ([Formula: see text]) and [Formula: see text] ([Formula: see text]), respectively. Best accuracies were [Formula: see text] and [Formula: see text]. Both validation setting results were consistent. For the hold-out dataset, results were consonant with most of those obtained in the literature in terms of class proportions. CONCLUSION: The development of machine learning systems for the classification of diabetes subtypes constitutes an important task to support physicians for fast and timely decision-making. We expect to deploy this methodology in a data analysis platform to conduct studies for identifying T2DM subtypes in patient records from hospitals.

Snail1 suppresses TGF-beta-induced apoptosis and is sufficient to trigger EMT in hepatocytes.

Although TGF-ß suppresses early stages of tumour development, it later contributes to tumour progression when cells become resistant to its suppressive effects. In addition to circumventing TGF-ß-induced growth arrest and apoptosis, malignant tumour cells become capable of undergoing epithelial-to-mesenchymal transition (EMT), favouring invasion and metastasis. Therefore, defining the mechanisms that allow cancer cells to escape from the suppressive effects of TGF-ß is fundamental to understand tumour progression and to design specific therapies. Here, we have examined the role of Snail1 as a suppressor of TGF-ß-induced apoptosis in murine non-transformed hepatocytes, rat and human hepatocarcinoma cell lines and transgenic mice. We show that Snail1 confers resistance to TGF-ß-induced cell death and that it is sufficient to induce EMT in adult hepatocytes, cells otherwise refractory to this transition upon exposure to TGF-ß. Furthermore, we show that Snail1 silencing prevents EMT and restores the cell death response induced by TGF-ß. As Snail1 is a known target of TGF-ß signalling, our data indicate that Snail1 might transduce the tumour-promoting effects of TGF-ß, namely the EMT concomitant with the resistance to cell death.

[Determination of copper, magnesium and zinc in mononuclear leukocytes by flame atomic absorption spectrometry]. / Determinación de cobre, magnesio y zinc en leucocitos mononucleares mediante espectrometría de absorción atómica con llama.

In this paper we evaluated a new micro-flow injector for the determination of the concentrations of Cu, Mg and Zn in mononuclear blood cells. This device analyzed sample volumes in the order of microliters by flame atomic absorption spectrometry; it is inexpensive, and easy to build and to adapt to the conventional injector of the atomic absorption spectrophotometer. Detection limits of 106, 65 and 37 microg L(-1) for Cu, Mg and Zn were obtained, respectively. The percentages of recovery tests were found between 98 and 110%.

An Immunogenic Model of KRAS-Mutant Lung Cancer Enables Evaluation of Targeted Therapy and Immunotherapy Combinations.

Mutations in oncogenes such as KRAS and EGFR cause a high proportion of lung cancers. Drugs targeting these proteins cause tumor regression but ultimately fail to elicit cures. As a result, there is an intense interest in how to best combine targeted therapies with other treatments, such as immunotherapies. However, preclinical systems for studying the interaction of lung tumors with the host immune system are inadequate, in part due to the low tumor mutational burden in genetically engineered mouse models. Here we set out to develop mouse models of mutant KRAS-driven lung cancer with an elevated tumor mutational burden by expressing the human DNA cytosine deaminase, APOBEC3B, to mimic the mutational signature seen in human lung cancer. This failed to substantially increase clonal tumor mutational burden and autochthonous tumors remained refractory to immunotherapy. However, establishing clonal cell lines from these tumors enabled the generation of an immunogenic syngeneic transplantation model of KRAS-mutant lung adenocarcinoma that was sensitive to immunotherapy. Unexpectedly, antitumor immune responses were not directed against neoantigens but instead targeted derepressed endogenous retroviral antigens. The ability of KRASG12C inhibitors to cause regression of KRASG12C -expressing tumors was markedly potentiated by the adaptive immune system, highlighting the importance of using immunocompetent models for evaluating targeted therapies. Overall, this model provides a unique opportunity for the study of combinations of targeted and immunotherapies in immune-hot lung cancer. SIGNIFICANCE: This study develops a mouse model of immunogenic KRAS-mutant lung cancer to facilitate the investigation of optimal combinations of targeted therapies with immunotherapies.

The Role of Tricarboxylic Acid Cycle Metabolites in Viral Infections.

Host cell metabolism is essential for the viral replication cycle and, therefore, for productive infection. Energy (ATP) is required for the receptor-mediated attachment of viral particles to susceptible cells and for their entry into the cytoplasm. Host cells must synthesize an array of biomolecules and engage in intracellular trafficking processes to enable viruses to complete their replication cycle. The tricarboxylic acid (TCA) cycle has a key role in ATP production as well as in the synthesis of the biomolecules needed for viral replication. The final assembly and budding process of enveloped viruses, for instance, require lipids, and the TCA cycle provides the precursor (citrate) for fatty acid synthesis (FAS). Viral infections may induce host inflammation and TCA cycle metabolic intermediates participate in this process, notably citrate and succinate. On the other hand, viral infections may promote the synthesis of itaconate from TCA cis-aconitate. Itaconate harbors anti-inflammatory, anti-oxidant, and anti-microbial properties. Fumarate is another TCA cycle intermediate with immunoregulatory properties, and its derivatives such as dimethyl fumarate (DMF) are therapeutic candidates for the contention of virus-induced hyper-inflammation and oxidative stress. The TCA cycle is at the core of viral infection and replication as well as viral pathogenesis and anti-viral immunity. This review highlights the role of the TCA cycle in viral infections and explores recent advances in the fast-moving field of virometabolism.

The inhibition of the epidermal growth factor (EGF) pathway enhances TGF-beta-induced apoptosis in rat hepatoma cells through inducing oxidative stress coincident with a change in the expression pattern of the NADPH oxidases (NOX) isoforms.

Transforming growth factor-beta (TGF-beta) induces apoptosis in hepatocytes, through a mechanism mediated by reactive oxygen species (ROS) production. Numerous tumoral cells develop mechanisms to escape from the TGF-beta-induced tumor suppressor effects. In this work we show that in FaO rat hepatoma cells inhibition of the epidermal growth factor receptor (EGFR) with the tyrphostin AG1478 enhances TGF-beta-induced cell death, coincident with an elevated increase in ROS production and GSH depletion. These events correlate with down-regulation of genes involved in the maintenance of redox homeostasis, such as gamma-GCS and MnSOD, and elevated mitochondrial ROS. Nonetheless, not all the ROS proceed from the mitochondria. Emerging evidences indicate that ROS production by TGF-beta is also mediated by the NADPH oxidase (NOX) system. TGF-beta-treated FaO cells induce nox1 expression. However, the treatment with TGF-beta and AG1478 greatly enhanced the expression of another family member: nox4. NOX1 and NOX4 targeted knock-down by siRNA experiments suggest that they play opposite roles, because NOX1 knockdown increases caspase-3 activity and cell death, whilst NOX4 knock-down attenuates the apoptotic process. This attenuation correlates with maintenance of GSH and antioxidant enzymes levels. In summary, EGFR inhibition enhances apoptosis induced by TGF-beta in FaO rat hepatoma cells through an increased oxidative stress coincident with a change in the expression pattern of NOX enzymes.

Acute Disseminated Encephalomyelitis: An Unusual Presentation of Human Immunodeficiency Virus Infection.

BACKGROUND: Acute disseminated encephalomyelitis (ADEM) is a rare inflammatory and demyelinating disorder of the central nervous system, with a distinct tendency to a perivenous localization of pathological changes. Children are the most affected population and frequently presented after exanthematous viral infections or vaccination. Due to the rarity of this disease, the annual incidence rate in the population is not precisely known. Case Presentation. Here, we present a 28-year-old male HIV-1 positive patient with an acute confusional state, a diminished alert status characterized by somnolence, hypoprosexia, and complex visual hallucinations. Neuroimages reported white matter demyelinating lesions, mainly affecting the semioval centers, the frontal lobe, and the left parietal lobe; hypointense on T1-weighted images, hyperintense on T2-weighted images and fluid-attenuated inversion recovery weighted images, DWI with restricted diffusion, and a parietal ring-enhancing lesion after IV gadolinium administration. Discussion. In HIV positive patients, the demyelinating disorders have a broader clinical spectrum that could be explained by the immunosuppressed state of the patients, the evolution of the disease, the use of medications, the opportunistic infections, and the environment. Due to this highly variable clinical spectrum, ADEM is a significant challenge for the physicians in HIV positive patients, causing a delay in the diagnosis and treatment. CONCLUSION: We suggest that ADEM should be considered among the differential diagnosis in HIV-infected patients with focal or multifocal neurological symptoms, particularly in encephalopathies with multifocal central nervous system involvement without severe immunosuppression.

Optimization of the treatment of wheat samples for the determination of phytic acid by HPLC with refractive index detection.

The treatment of wheat samples was optimized before the determination of phytic acid by high-performance liquid chromatography with refractive index detection. Drying by lyophilization and oven drying were studied; drying by lyophilization gave better results, confirming that this step is critical in preventing significant loss of analyte. In the extraction step, washing of the residue and collection of this water before retention of the phytates in the NH2 Sep-Pak cartridge were important. The retention of phytates in the NH2 Sep-Pak cartridge and elimination of the HCI did not produce significant loss (P = 0.05) in the phytic acid content of the sample. Recoveries of phytic acid averaged 91%, which is a substantial improvement with respect to values reported by others using this methodology.

RAC1P29S Induces a Mesenchymal Phenotypic Switch via Serum Response Factor to Promote Melanoma Development and Therapy Resistance.

RAC1 P29 is the third most commonly mutated codon in human cutaneous melanoma, after BRAF V600 and NRAS Q61. Here, we study the role of RAC1P29S in melanoma development and reveal that RAC1P29S activates PAK, AKT, and a gene expression program initiated by the SRF/MRTF transcriptional pathway, which results in a melanocytic to mesenchymal phenotypic switch. Mice with ubiquitous expression of RAC1P29S from the endogenous locus develop lymphoma. When expressed only in melanocytes, RAC1P29S cooperates with oncogenic BRAF or with NF1-loss to promote tumorigenesis. RAC1P29S also drives resistance to BRAF inhibitors, which is reversed by SRF/MRTF inhibitors. These findings establish RAC1P29S as a promoter of melanoma initiation and mediator of therapy resistance, while identifying SRF/MRTF as a potential therapeutic target.

Differential intracellular signalling induced by TGF-beta in rat adult hepatocytes and hepatoma cells: implications in liver carcinogenesis.

The transforming growth factor-beta (TGF-beta) regulates hepatocyte growth, inhibiting proliferation and inducing apoptosis. Indeed, escaping from the TGF-beta suppressor actions might be a prerequisite for liver tumour progression. In this work we show that TGF-beta plays a dual role in regulating apoptosis in FaO rat hepatoma cells, since, in addition to its pro-apoptotic effect, TGF-beta also activates survival signals, such as AKT, the epidermal growth factor receptor (EGFR) being required for its activation. TGF-beta induces the expression of the EGFR ligands transforming growth factor-alpha (TGF-alpha) and heparin-binding EGF-like growth factor (HB-EGF) and induces intracellular re-localization of the EGFR. Cells that overcome the apoptotic effects of TGF-beta undergo morphological changes reminiscent of an epithelial-mesenchymal transition (EMT) process. In contrast, TGF-beta does not activate AKT in adult hepatocytes, which correlates with lack of EGFR transactivation and no response to EGFR inhibitors. Although TGF-beta induces TGF-alpha and HB-EGF in adult hepatocytes, these cells show very low expression of TACE/ADAM 17 (TNF-alpha converting enzyme), which is required for EGFR ligand proteolysis and activation. Furthermore, adult hepatocytes do not undergo EMT processes in response to TGF-beta, which might be due, at least in part, to the fact that F-actin re-organization induced by TGF-beta in FaO cells require the EGFR pathway. Finally, results indicate that EGFR transactivation does not block TGF-beta-induced cell cycle arrest in FaO cells, but must be interfering with the pro-apoptotic signalling. In conclusion, TGF-beta is a suppressor factor for adult quiescent hepatocytes, but not for hepatoma cells, where it plays a dual role, both suppressing and promoting carcinogenesis.

Activation of NADPH oxidase by transforming growth factor-beta in hepatocytes mediates up-regulation of epidermal growth factor receptor ligands through a nuclear factor-kappaB-dependent mechanism.

The TGF-beta (transforming growth factor-beta) induces survival signals in foetal rat hepatocytes through transactivation of EGFR (epidermal growth factor receptor). The molecular mechanism is not completely understood, but both activation of the TACE (tumour necrosis factor alpha-converting enzyme)/ADAM17 (a disintegrin and metalloproteinase 17; one of the metalloproteases involved in shedding of the EGFR ligands) and up-regulation of TGF-alpha and HB-EGF (heparin-binding epidermal growth factor-like growth factor) appear to be involved. In the present study, we have analysed the molecular mechanisms that mediate up-regulation of the EGFR ligands by TGF-beta in foetal rat hepatocytes. The potential involvement of ROS (reactive oxygen species), an early signal induced by TGF-beta, and the existence of an amplification loop triggered by initial activation of the EGFR, have been studied. Results indicate that DPI (diphenyleneiodonium) and apocynin, two NOX (NADPH oxidase) inhibitors, and SB431542, an inhibitor of the TbetaR-I (TGF-beta receptor I), block up-regulation of EGFR ligands and Akt activation. Different members of the NOX family of genes are expressed in hepatocytes, included nox1, nox2 and nox4. TGF-beta up-regulates nox4 and increases the levels of Rac1 protein, a known regulator of both Nox1 and Nox2, in a TbetaR-I-dependent manner. TGF-beta mediates activation of the nuclear factor-kappaB pathway, which is inhibited by DPI and is required for up-regulation of TGF-alpha and HB-EGF. In contrast, EGFR activation is not required for TGF-beta-induced up-regulation of those ligands. Considering previous work that has established the role of ROS in apoptosis induced by TGF-beta in hepatocytes, the results of the present study indicate that ROS might mediate both pro- and anti-apoptotic signals in TGF-beta-treated cells.

Disruption of the Interaction of RAS with PI 3-Kinase Induces Regression of EGFR-Mutant-Driven Lung Cancer.

RAS family GTPases contribute directly to the regulation of type I phosphoinositide 3-kinases (PI3Ks) via RAS-binding domains in the PI3K catalytic p110 subunits. Disruption of this domain of p110α impairs RAS-mutant-oncogene-driven tumor formation and maintenance. Here, we test the effect of blocking the interaction of RAS with p110α on epidermal growth factor receptor (EGFR)-mutant-driven lung tumorigenesis. Disrupting the RAS-PI3K interaction inhibits activation of both AKT and RAC1 in EGFR-mutant lung cancer cells, leading to reduced growth and survival, and inhibits EGFR-mutant-induced tumor onset and promotes major regression of established tumors in an autochthonous mouse model of EGFR-mutant-induced lung adenocarcinoma. The RAS-PI3K interaction is thus an important signaling node and potential therapeutic target in EGFR-mutant lung cancer, even though RAS oncogenes are not themselves mutated in this setting, suggesting different strategies for tackling tyrosine kinase inhibitor resistance in lung cancer.

TGF-beta dependent regulation of oxygen radicals during transdifferentiation of activated hepatic stellate cells to myofibroblastoid cells.

BACKGROUND: The activation of hepatic stellate cells (HSCs) plays a pivotal role during liver injury because the resulting myofibroblasts (MFBs) are mainly responsible for connective tissue re-assembly. MFBs represent therefore cellular targets for anti-fibrotic therapy. In this study, we employed activated HSCs, termed M1-4HSCs, whose transdifferentiation to myofibroblastoid cells (named M-HTs) depends on transforming growth factor (TGF)-beta. We analyzed the oxidative stress induced by TGF-beta and examined cellular defense mechanisms upon transdifferentiation of HSCs to M-HTs. RESULTS: We found reactive oxygen species (ROS) significantly upregulated in M1-4HSCs within 72 hours of TGF-beta administration. In contrast, M-HTs harbored lower intracellular ROS content than M1-4HSCs, despite of elevated NADPH oxidase activity. These observations indicated an upregulation of cellular defense mechanisms in order to protect cells from harmful consequences caused by oxidative stress. In line with this hypothesis, superoxide dismutase activation provided the resistance to augmented radical production in M-HTs, and glutathione rather than catalase was responsible for intracellular hydrogen peroxide removal. Finally, the TGF-beta/NADPH oxidase mediated ROS production correlated with the upregulation of AP-1 as well as platelet-derived growth factor receptor subunits, which points to important contributions in establishing antioxidant defense. CONCLUSION: The data provide evidence that TGF-beta induces NADPH oxidase activity which causes radical production upon the transdifferentiation of activated HSCs to M-HTs. Myofibroblastoid cells are equipped with high levels of superoxide dismutase activity as well as glutathione to counterbalance NADPH oxidase dependent oxidative stress and to avoid cellular damage.

Involvement of EGF receptor and c-Src in the survival signals induced by TGF-beta1 in hepatocytes.

Transforming growth factor beta1 (TGF-beta1) belongs to a family of polypeptide factors, whose cytostatic and apoptotic functions help restrain the growth of mammalian cells. Although solid data established the role of TGF-beta's as suppressor factors in tumorigenic processes, in the context of an advanced stage of disease, TGF-beta's could also play a pro-oncogenic role. We have previously shown that TGF-beta1 induces both pro- and anti-apoptotic signals in foetal rat hepatocytes. In this work, we have focused on its anti-apoptotic mechanism. We show that TGF-beta1 activates the epidermal growth factor receptor (EGFR) and phosphorylates c-Src. EGFR is required for Akt activation. Blocking EGFR signalling amplifies the apoptotic response to TGF-beta1. TGF-beta1 induced a rapid activation of the tumour necrosis factor-alpha-converting enzyme (TACE/ADAM (a disintegrin and metalloprotease) 17). Inhibitors of TACE considerably attenuated Akt activation, which suggests that TGF-beta1 activates EGF signalling in hepatocytes by promoting shedding of EGF-like ligands. The activation of c-Src by TGF-beta1 is EGFR dependent and is required for full Akt phosphorylation and cell survival. Inhibition of EGFR does not block the epithelial-mesenchymal transition (EMT) induced by TGF-beta1 in hepatocytes, which indicates that activation of EGFR plays an essential role in impairing apoptosis, but it is dispensable for the EMT process.

Mortality Reduction in Septic Shock by Plasma Adsorption (ROMPA): a protocol for a randomised clinical trial.

INTRODUCTION: There is a lack of evidence in the efficacy of the coupled plasma filtration adsorption (CPFA) to reduce the mortality rate in septic shock. To fill this gap, we have designed the ROMPA study (Mortality Reduction in Septic Shock by Plasma Adsorption) to confirm whether treatment with an adequate dose of treated plasma by CPFA could confer a clinical benefit. METHODS AND ANALYSIS: Our study is a multicentric randomised clinical trial with a 28-day and 90-day follow-up and allocation ratio 1:1. Its aim is to clarify whether the application of high doses of CPFA (treated plasma ≥0.20 L/kg/day) in the first 3 days after randomisation, in addition to the current clinical practice, is able to reduce hospital mortality in patients with septic shock in intensive care units (ICUs) at 28 and 90 days after initiation of the therapy. The study will be performed in 10 ICUs in the Southeast of Spain which follow the same protocol in this disease (based on the Surviving Sepsis Campaign). Our trial is designed to be able to demonstrate an absolute mortality reduction of 20% (α=0.05; 1-ß=0.8; n=190(95×2)). The severity of the process, ensuring the recruitment of patients with a high probability of death (50% in the control group), will be achieved through an adequate stratification by using both severity scores and classical definitions of severe sepsis/septic shock and dynamic parameters. Our centres are fully aware of the many pitfalls associated with previous medical device trials. Trying to reduce these problems, we have developed a training programme to improve the CPFA use (especially clotting problems). ETHICS AND DISSEMINATION: The protocol was approved by the Ethics Committees of all the participant centres. The findings of the trial will be disseminated through peer-reviewed journals, as well as national and international conference presentations. TRIAL REGISTRATION NUMBER: NCT02357433; Pre-results.

Determination of selenium and iodine in human thyroids.

This study focuses on the determination of selenium and iodine in human thyroids. The glands were digested using nitric acid in a microwave oven. Selenium was determined by inductively coupled plasma optical emission spectrometry (ICP-OES) using a new sample introduction system consisting of a reduction system coupled to a hydride generation nebulizer (DHGN). Iodine was determined by using the Sandell-Kolthoff procedure. The detections limits were 0.2 ng/mL and 0.3 ng/mL for the determination method of selenium and iodine, respectively. The amount of iodine in the whole gland was 3.44 +/- 1.11 microg/g. The lowest iodine level was 2.34 microg/g and the highest 5.21 microg/g. The lowest selenium concentration for a single sample was 505 +/- 51 ng/g and the highest 1495 +/- 204 ng/g depending on the fraction of the gland selected.

Source of early reactive oxygen species in the apoptosis induced by transforming growth factor-beta in fetal rat hepatocytes.

Transforming growth factor-beta (TGF-beta) induces an oxidative stress process in hepatocytes that mediates its apoptotic activity. To determine the cellular source of the early reactive oxygen species (ROS) generated by fetal rat hepatocytes in response to TGF-beta, we used inhibitors that block different ROS-producing systems. Diphenyleneiodonium, which inhibits NADPH oxidase and other flavoproteins, completely blocked the increase in ROS induced by TGF-beta, coincidently with an impairment of caspase-3 activation and cell death. Rotenone, an inhibitor of the NADH dehydrogenase in mitochondrial complex I, attenuated, but did not completely inhibit, ROS-production, caspase activation, and cell death mediated by TGF-beta. No significant protection was observed with inhibitors of other ROS-producing systems, such as cytochrome P450 (metyrapone), cyclooxygenase (indomethacin), and xanthine oxidase (allopurinol). Additional experiments have indicated that two different mechanisms could be involved in the early ROS production by TGF-beta. First, an inducible (cycloheximide-inhibited) NADPH oxidase-like system could account for the extramitochondrial production of ROS. Second, TGF-beta could increase ROS by a rapid downregulation of antioxidant genes. In particular, intramitochondrial ROS would increase by depletion of MnSOD. Finally, glutathione depletion is a late event and it would be more the consequence than the cause of the increase in ROS induced by TGF-beta.

Simultaneous determination of nickel, iron, and copper in margarine by inductively coupled plasma-atomic emission spectroscopy after sample emulsification.

Nickel, iron, and copper were determined in margarine samples by using emulsification followed by inductively coupled plasma-atomic emission spectroscopy. Sample treatment and instrumental conditions were optimized, and the results were compared with those obtained by a pseudodigestion method in order to evaluate the compatibility of both methodologies. The optimum amount of margarine in the emulsion was 35% when the surfactant Tween 80 was added as the emulsifier. Copper was below the detection limits of both methodologies, i.e., digestion and emulsion; iron and nickel concentrations found by both methodologies were similar. The detection limits of the emulsion method were 0.002, 0.015, and 0.092 mg/kg for copper, iron, and nickel, respectively. A benefit of the emulsion method is that laborious and lengthy sample digestion procedures are avoided. In addition, accurate and precise results are obtained. Recoveries with the emulsion method ranged from 101 to 104%, with relative standard deviations of < or = 6%.