Papers by Pablo Hernández Olmos
Publication in the conference proceedings of EUSIPCO, Glasgow, Scotland, 2009
Epidemiologic Methods, 2021
Objectives One important variable influencing day-to-day decisions in COVID-19 pandemic has been ... more Objectives One important variable influencing day-to-day decisions in COVID-19 pandemic has been an impending shortage of mechanical ventilators due to the large number of people that become infected with the virus due to its high contagiousness. We developed a stepwise Markov model (a) to make a short-term prediction of the number of patients on ventilator, and (b) to determine a possible date for a ventilator crisis. Methods Starting with the exponential curve of new cases in the previous 14 days, we calculated a Markov model every 5 days thereafter, resulting in a daily estimate of patients on ventilator for the following 25 days, which we compared with the daily number of devices in use to predict a date for ventilator crisis. Results During the modeled period, the observed and predicted Markov curves of patients on ventilator were very similar, a finding confirmed by both linear regression (r=0.984; p<0.0001) and the near coincidence with the identity line. Our model estimat...
Obesity, 2020
Objective: This study aimed to determine the relationship between metabolic flexibility (MetFlex)... more Objective: This study aimed to determine the relationship between metabolic flexibility (MetFlex) measured during a euglycemic-hyperinsulinemic clamp and a prolonged fast. This study also analyzed the association between MetFlex and metabolic health. Methods: Eighteen healthy men (mean [SD]: 22 [2] years old; BMI: 22 [1] kg/m 2) performed two sessions: (1) euglycemic-hyperinsulinemic clamp (2 mIU/kg of insulin per minute) and (2) ~20-hour fast. Clamp MetFlex corresponded to the change in (Δ) respiratory quotient (RQ) (ΔRQ = postchallenge RQ − prechallenge RQ) adjusted for M value and prechallenge RQ. Prolonged fast MetFlex corresponded to the ΔRQ adjusted for the Δβ-hydroxybutyrate and prechallenge RQ. Results: MetFlex during the clamp related directly with MetFlex during prolonged fast (r = 0.59, P = 0.014). Using the median of MetFlex for each challenge, this study split participants into high or low MetFlex. Participants with high or low MetFlex to both challenges were identified. Participants with high MetFlex had 3% lower serum low-density lipoprotein cholesterol than participants with low MetFlex (P = 0.021). Conclusions: Measuring MetFlex during a clamp or a prolonged fast produces similar results, despite challenging the oxidation of different substrates. An impaired MetFlex in response to these challenges may be an early event in the development of abnormal lipid metabolism.
Current Vascular Pharmacology, 2020
Obesity and Gestational Diabetes Mellitus (GDM) are the most frequent pathologies affecting mothe... more Obesity and Gestational Diabetes Mellitus (GDM) are the most frequent pathologies affecting mothers and offspring during pregnancy. Both conditions have shown a sustained increase in their prevalence in recent years, and they worsen the outcome of pregnancy and the long-term health of mothers. Obesity increases the risk of GDM and pre-eclampsia during pregnancy and elevates the risk of developing metabolic syndrome in later life. Offspring of obese mothers have an increased risk of obstetric morbidity and mortality and, consistent with the developmental origins of health and disease, a long term risk of childhood obesity and metabolic dysfunction. On the other hand, GDM also increases the risk of pre-eclampsia, caesarean section, and up to 50% of women will develop type 2 diabetes later in life. From a fetal point of view, it increases the risk of macrosomia, large-for-gestational-age fetuses, shoulder dystocia and birth trauma. The insulin resistance and inflammatory mediators rele...
Journal of Diabetes Research, 2019
Most peripheral serotonin (5-hydroxytryptamine (5HT)) is synthetized in the gut with platelets be... more Most peripheral serotonin (5-hydroxytryptamine (5HT)) is synthetized in the gut with platelets being its main circulating reservoir. 5HT is acting as a hormone in key organs to regulate glucose and lipid metabolism. However, the relation between platelet 5HT levels and traits related to glucose homeostasis and lipid metabolism in humans remains poorly explored. The objectives of this study were (a) to assess the association between platelet 5HT levels and plasma concentration of nonesterified fatty acids (NEFAs) and some adipokines including leptin and its soluble leptin receptor (sOb-R), (b) to assess the association between platelet 5HT levels and anthropometric traits and indexes of insulin secretion/sensitivity derived from oral glucose tolerance test (OGTT), and (c) to evaluate changes in platelet 5HT levels in response to OGTT. In a cross-sectional study, 59 normoglycemic women underwent a standard 2-hour OGTT. Plasma leptin, sOb-R, total and high molecular weight adiponectin,...
Canadian Journal of Diabetes, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Obstetrics and Gynaecology Research, 2018
Aim: Prevalence of type 2 diabetes mellitus (T2DM) during childbearing age in Chile had a 47-fold... more Aim: Prevalence of type 2 diabetes mellitus (T2DM) during childbearing age in Chile had a 47-fold rise in 7 years, reaching 120 844 women, half of which are unaware of their condition. We aimed to project pregnancies and births among Chilean women of childbearing age (WCBA) with T2DM and report the incidence of birth defects and the associated years of life lost and lifetime costs. Methods: Markov model of cohort of WCBA with T2DM (WCBA-DM) with a 20-year time horizon (2018-2037), using data from previous studies. Two scenarios were assessed: scenario A: no universal detection of T2DM and scenario B: universal screening of T2DM using glycosylated hemoglobin levels. Both lifetime costs and disability-adjusted life years (DALY) were calculated with a 5% discount rate (US$ of 2017). Results: In scenario A, 12 163 infants with birth defects could be born among the analyzed cohort, resulting in 243 260 years of life lost, 296 652 DALY and in lifetime costs of US$ 1 957 657 966. In scenario B, the first three figures could be reduced by 70.4% to 3599 infants with birth defects, 71 980 years of life lost and 87 794 DALY. Due to the addition of diabetes screening and new patient costs to scenario B, there would be a lesser reduction (67.3%) in total lifetime costs, to US$ 640 669 296. Conclusion: Screening of diabetes in WCBA would yield a 20-year reduction of 70.4% in the number of infants with birth defects, years of life lost and DALY. Total lifetime costs could be reduced by 67.3%.
Respiratory Research, 2018
Background: Gastric contents aspiration is a high-risk condition for acute lung injury (ALI). Con... more Background: Gastric contents aspiration is a high-risk condition for acute lung injury (ALI). Consequences range from subclinical pneumonitis to respiratory failure, depending on the volume of aspirate. A large increment in inflammatory cells, an important source of elastase, potentially capable of damaging lung tissue, has been described in experimental models of aspiration. We hypothesized that in early stages of aspiration-induced ALI, there is proteolytic degradation of elastin, preceding collagen deposition. Our aim was to evaluate whether after a single orotracheal instillation of gastric fluid, there is evidence of elastin degradation. Methods: Anesthesized Sprague-Dawley rats received a single orotracheal instillation of gastric fluid and were euthanized 4, 12 and 24 h and at day 4 after instillation (n = 6/group). We used immunodetection of soluble elastin in lung tissue and BALF and correlated BALF levels of elastin degradation products with markers of ALI. We investigated possible factors involved in elastin degradation and evaluated whether a similar pattern of elastin degradation can be found in BALF samples of patients with interstitial lung diseases known to have aspirated. Non-parametric ANOVA (Kruskall-Wallis) and linear regression analysis were used. Results: We found evidence of early proteolytic degradation of lung elastin. Elastin degradation products are detected both in lung tissue and BALF in the first 24 h and are significantly reduced at day 4. They correlate significantly with ALI markers, particularly PMN cell count, are independent of acidity and have a similar molecular weight as those obtained using pancreatic elastase. Evaluation of BALF from patients revealed the presence of elastin degradation products not present in controls that are similar to those found in BALF of rats treated with gastric fluid. Conclusions: A single instillation of gastric fluid into the lungs induces early proteolytic degradation of elastin, in relation to the magnitude of alveolar-capillary barrier derangement. PMN-derived proteases released during ALI are mostly responsible for this damage. BALF from patients showed elastin degradation products similar to those found in rats treated with gastric fluid. Long-lasting effects on lung elastic properties could be expected under conditions of repeated instillations of gastric fluid in experimental animals or repeated aspiration events in humans.
American journal of physiology. Lung cellular and molecular physiology, Jan 10, 2018
Recurrent aspiration of gastric contents has been associated with several interstitial lung disea... more Recurrent aspiration of gastric contents has been associated with several interstitial lung diseases. Despite this association, the pathogenic role of aspiration in these diseases has been poorly studied and little is known about extracellular matrix (ECM) changes in animal models of repetitive events of aspiration. Our aim was to study the repair phase of lung injury induced by each of several instillations of gastric fluid in Sprague-Dawley rats to evaluate changes in ECM and their reversibility. Anesthetized animals received weekly orotracheal instillations of gastric fluid for 1, 2, 3 and 4 weeks and were sacrificed at day 7 after last instillation. For reversibility studies, another group received 7 weekly instillations and was sacrificed at day 7 or 60 after last instillation. Biochemical and histological measurements were used to evaluate ECM changes. Lung hydroxyproline content increased progressively and H-E, Masson's trichrome and alpha-SMA stains showed that after a s...
Respiratory research, Apr 10, 2018
Gastric contents aspiration in humans has variable consequences depending on the volume of aspira... more Gastric contents aspiration in humans has variable consequences depending on the volume of aspirate, ranging from subclinical pneumonitis to respiratory failure with up to 70% mortality. Several experimental approaches have been used to study this condition. In a model of single orotracheal instillation of gastric fluid we have shown that severe acute lung injury evolves from a pattern of diffuse alveolar damage to one of organizing pneumonia (OP), that later resolves leaving normal lung architecture. Little is known about mechanisms of injury resolution after a single aspiration that could be dysregulated with repetitive aspirations. We hypothesized that, in a similar way to cutaneous wound healing, apoptosis may participate in lung injury resolution by reducing the number of myofibroblasts and by affecting the balance between proteases and antiproteases. Our aim was to study activation of apoptosis as well as MMP-2/TIMP-2 balance in the sub-acute phase (4-14 days) of gastric fluid...
PloS one, 2017
Pancreatic β-cells synthesize and release serotonin (5 hydroxytryptamine, 5HT); however, the role... more Pancreatic β-cells synthesize and release serotonin (5 hydroxytryptamine, 5HT); however, the role of 5HT receptors on glucose stimulated insulin secretion (GSIS) and the mechanisms mediating this function is not fully understood. The aims of this study were to determine the expression profile of 5HT receptors in murine MIN6 β-cells and to examine the effects of pharmacological activation of 5HT receptor Htr2b on GSIS and mitochondrial function. mRNA levels of 5HT receptors in MIN6 cells were quantified by RT qPCR. GSIS was assessed in MIN6 cells in response to global serotonergic activation with 5HT and pharmacological Htr2b activation or inhibition with BW723C86 or SB204741, respectively. In response to Htr2b activation also was evaluated the mRNA and protein levels of PGC1α and PPARy by RT-qPCR and western blotting and mitochondrial function by oxygen consumption rate (OCR) and ATP cellular content. We found that mRNA levels of most 5HT receptors were either very low or undetectab...
PloS one, 2016
Insulin secretion correlates inversely with insulin sensitivity, which may suggest the existence ... more Insulin secretion correlates inversely with insulin sensitivity, which may suggest the existence of a crosstalk between peripheral organs and pancreas. Such interaction might be mediated through glucose oxidation that may drive the release of circulating factors with action on insulin secretion. To evaluate the association between whole-body carbohydrate oxidation and circulating factors with insulin secretion to consecutive oral glucose loading in non-diabetic individuals. Carbohydrate oxidation was measured after an overnight fast and for 6 hours after two 3-h apart 75-g oral glucose tolerance tests (OGTT) in 53 participants (24/29 males/females; 34±9 y; 27±4 kg/m2). Insulin secretion was estimated by deconvolution of serum C-peptide concentration, β cell function by mathematical modelling and insulin sensitivity from an OGTT. Circulating lactate, free-fatty acids (FFA) and candidate chemokines were assessed before and after OGTT. The effect of recombinant RANTES (regulated on act...
Revista Medica De Chile, Oct 8, 2014
Respiratory Research, 2016
Background: Gastric contents aspiration in humans is a risk factor for severe respiratory failure... more Background: Gastric contents aspiration in humans is a risk factor for severe respiratory failure with elevated mortality. Although aspiration-induced local lung inflammation has been studied in animal models, little is known about extrapulmonary effects of aspiration. We investigated whether a single orotracheal instillation of whole gastric fluid elicits a liver acute phase response and if this response contributes to enrich the alveolar spaces with proteins having antiprotease activity. Methods: In anesthetized Sprague-Dawley rats receiving whole gastric fluid, we studied at different times after instillation (4 h −7 days): changes in blood cytokines and acute phase proteins (fibrinogen and the antiproteases alpha1-antitrypsin and alpha2-macroglobulin) as well as liver mRNA expression of the two antiproteases. The impact of the systemic changes on lung antiprotease defense was evaluated by measuring levels and bioactivity of antiproteases in broncho-alveolar lavage fluid (BALF). Markers of alveolar-capillary barrier derangement were also studied. Non-parametric ANOVA (Kruskall-Wallis) and linear regression analysis were used. Results: Severe peribronchiolar injury involving edema, intra-alveolar proteinaceous debris, hemorrhage and PMNn cell infiltration was seen in the first 24 h and later resolved. Despite a large increase in several lung cytokines, only IL-6 was found elevated in blood, preceding increased liver expression and blood concentration of both antiproteases. These changes, with an acute phase response profile, were significantly larger for alpha2-macroglobulin (40-fold increment in expression with 12-fold elevation in blood protein concentration) than for alpha1-antitrypsin (2-3 fold increment in expression with 0.5-fold elevation in blood protein concentration). Both the increment in capillary-alveolar antiprotease concentration gradient due to increased antiprotease liver synthesis and a timely-associated derangement of the alveolar-capillary barrier induced by aspiration, contributed a 58-fold and a 190-fold increase in BALF alpha1-antitrypsin and alpha2-macroglobulin levels respectively (p < 0.001).
2015 IEEE Global Communications Conference (GLOBECOM), 2014
In this paper we consider distributed allocation problems with memory constraint limits. Firstly,... more In this paper we consider distributed allocation problems with memory constraint limits. Firstly, we propose a tractable relaxation to the problem of optimal symmetric allocations from [1]. The approximated problem is based on the Q-error function, and its solution approaches the solution of the initial problem, as the number of storage nodes in the network grows. Secondly, exploiting this relaxation, we are able to formulate and to solve the problem for storage allocations for memory-limited DSS storing and arbitrary memory profiles. Finally, we discuss the extension to the case of multiple data objects, stored in the DSS.
Revista Medica De Chile, Mar 13, 2013
MITOCHONDRIAL DNA HETEROPLASMY OF THE M.3243A>G MUTATION IN MATERNALLY INHERITED DIABETES AND ... more MITOCHONDRIAL DNA HETEROPLASMY OF THE M.3243A>G MUTATION IN MATERNALLY INHERITED DIABETES AND DEAFNESS. A STUDY IN ONE PATIENT Maternally Inherited Diabetes and Deafness (MIDD) is caused by mutations in mitochondrial DNA (mtDNA), mainly m.3243A>G. Severity, onset and clinical phenotype of MIDD patients are partially determined by the proportion of mutant mitochondrial DNA copies in each cell and tissue (heteroplasmy). The identification of MIDD allows a correct treatment with insulin avoiding drugs that may interfere with mitochondrial electron chain transport. We estimated the degree of heteroplasmy of the mutation m.3243A>G from blood, saliva, hair root and a muscle biopsy using quantitative PCR (qPCR) in a female adult patient. For this purpose, PCR products were inserted in a vector creating plasmids with 3243A or G. Mutant and wild-type vectors were mixed in different proportions to create a calibration curve used to interpolate heteroplasmy percentages with qPCR threshold cycles.The proportions of m.3243AG heteroplasmy were 62% (muscle), 14% (saliva), 6% (blood leukocytes) and 3% in hair root. Quantitative analysis of heteroplasmy showed marked variations in different tissues (highest in muscle and lowest in blood). Given the relatively high heteroplasmy found in saliva, this type of biological sample may represent an adequate non-invasive way for assessing the presence of m.3243A>G mutations in epidemiologic studies. Normal 0 21 false false false ES X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}
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Papers by Pablo Hernández Olmos