Serum myostatin is associated with central-to-peripheral arterial stiffness gradient in healthy adolescents. The MACISTE Study.

BACKGROUND: myostatin is a protein compound structurally related to the TGF-beta protein, which plays a pivotal role in regulating muscle growth and extracellular matrix production. exerts both profibrotic and antihypertrophic effects on vascular smooth muscle cells. Aim of the study was to explore the potential association between serum myostatin levels (sMSTN) and carotid-femoral pulse-wave velocity (cf-PWV), carotid-radial pulse wave velocity (cr-PWV), and their ratio (PWVr), in a cohort of healthy adolescents. METHODS: a cohort of 128 healthy subjects (mean age 17±2 years, 59% male) was randomly selected from participants to the MACISTE (Metabolic And Cardiovascular Investigation at School, TErni) study. sMSTN was assessed utilizing an enzyme-linked immunosorbent assay. PWVs were measured in the supine position using high-fidelity applanation tonometry. RESULTS: The mean cf-PWV was 5.1±0.9 m/s, cr-PWV was 6.9±0.9 m/s, PWVr was 0.75±0.12. PWVr exhibited a linear increase across increasing quartiles of sMSTN (0.71±0.1, 0.74±0.1, 0.7±0.1, 0.77±0.1, p for trend=0.03), whereas the association between sMSTN and each single component of PWVr (cf-PWV, cr-PWV) did not attain statistical significance. Quartiles of sMSTN displayed a positive trend with serum HDL-cholesterol (p=0.01) and a negative one with LDL-cholesterol (p=0.01). In a multivariate linear model, the association between PWVr and sMSTN was independent from SBP values, age, sex, heart rate, BMI, HDL-cholesterol and HOMA Index. CONCLUSIONS: In healthy adolescents, sMSTN showed independent associations with PWVr, a measure of central-to-peripheral arterial stiffness gradient. sMSTN may exert differential effects on the structural and functional properties of the arterial wall.

Operators' radiation exposure reduction during cardiac catheterization using a removable shield.

Cardiac catheterization through radial access is associated with significant ionizing radiation exposure for the operator. We aimed at evaluating whether a removable shield placed upon the patient could impact favorably on annual radiation exposure for the operator. We designed a pre-post study comparing radiation exposure in a total of five operators under standard protection procedures (first period) and after applying a removable shield (second period). Each period included all the procedures performed in 1 year. Radiation exposure was measured through three dosimeters on each operator. A total of 1610 procedures were performed during the first period, and 1670 during the second period. For each operator, Fluoroscopy Time (FT) per exam did not differ between the two periods (13.1 ± 1 vs 12.9 ± 2 min/exam, p = 0.73), whereas Dose-Area Product (DAP) per procedure was slightly higher in the second period (5.247 ± 651 vs 6.374 ± 967 mGy/cm2, p < 0.01). The use of a removable shield significantly reduced operators' radiation dose at the left bracelet (64.3 ± 13.3 µSv/exam vs 23.8 ± 6.0 µSv/exam, p = 0.003). This remained significant even after adjustment for DAP per procedure (p = 0.015) and number of operators participating to each procedure (p = 0.013), whereas no significant difference was observed for card (5.6 ± 10.5 µSv/exam vs 0.9 ± 0.3 µSv/exam, p = 0.36) and neck bands (3.3 ± 4.5 µSv/exam vs 2.0 ± 2.0 µSv/exam, p = 0.36) dosimeters. The use of a removable shield during cardiac catheterization reduces radiation exposure at the level of the operator's upper limb, whereas no difference was found for other body parts. This may help in reducing radiation exposure of operator's hand. DAP increase merits further investigation.

Diagnosis and treatment of hypertensive emergencies and urgencies among Italian emergency and intensive care departments. Results from an Italian survey: Progetto GEAR (Gestione dell'Emergenza e urgenza in ARea critica).

Hypertensive emergencies (HE) and urgencies (HU) are frequent causes of patients referral to Emergency Department (ED) and the approach may be different according to local clinical practice. Our aim was to explore awareness, management, treatment and counselling after discharge of HE and HU in Italy, by mean of an on-line survey. The young investigator research group of the Italian Society of Hypertension developed a 23-item questionnaire spread by e-mail invitation to the members of Italian Scientific societies in the field of Hypertension. 665 questionnaires were collected from EDs, Emergency and Urgency Medicine, Cardiology or Coronary Units, Internal Medicines, Intensive care, Stroke units. Symptoms considered suspicious of acute organ damage were: chest pain (89.0%), visual disturbances (89.8%), dyspnoea (82.7%), headache (82.1%), dizziness (52.0%), conjunctival haemorrhages (41.5%), tinnitus (38.2%) and epistaxis (34.4%). Exams more frequent prescribed were: electrocardiogram (97.2%), serum creatinine (91.4%), markers of cardiomyocyte necrosis (66.2%), echocardiography (65.1%). The use of intravenous or oral medications to treat HEs was 94.7% and 3.5%, while for HUs 24.4% and 70.8% respectively. Of note, a surprisingly high percentage of physicians (22 % overall, 24.5% in North Italy) used to prescribe sublingual nifedipine. After discharge, home blood pressure monitoring and general practitioner re-evaluation were more frequently suggested, while ambulatory blood pressure monitoring and hypertension specialist examination were less prescribed. The differences observed across the different macro-areas, regarded prescription of diagnostic test and drug administration. This survey depicts a complex situation of shades and lights in the real-life management of HE and HU in Italy.

Heritability of arterial stiffness and carotid intima-media thickness: an Italian twin study.

BACKGROUND AND AIMS: Carotid intima-media thickness (IMT) and arterial stiffness parameters, including aortic augmentation index (AIx) and pulse wave velocity (PWV), are independent predictors of stroke and cardiovascular disease. Genetic effects on these traits were never explored in a Mediterranean country. The present study aims to quantify the contribution of genes, environment and age to carotid IMT and aortic Aix and PWV. METHODS AND RESULTS: The twin design was used. A total of 348 adult twins from the Italian Twin Register underwent measurements of carotid IMT and aortic PWV and AIx in three university hospitals located in Rome, Padua and Perugia. Carotid IMT was measured by B-mode ultrasound, aortic PWV and AIx by Arteriograph. Genetic modelling was performed to decompose total variance of traits into genetic, shared and unshared environmental and age components. For each phenotype, the best-fitting model included additive genetic, unshared environmental and age effects. For IMT, heritability was 0.32 (95% confidence interval (CI): 0.25-0.38), unshared environmental component was 0.25 (0.18-0.32) and age contribution was 0.44 (0.39-0.49). For AIx and PWV, heritabilities were 0.42 (0.29-0.55) and 0.49 (0.35-0.62), unshared environmental components were 0.31 (0.22-0.44) and 0.37 (0.26-0.51) and age contributions were 0.27 (0.16-0.39) and 0.14 (0.06-0.24), respectively. CONCLUSION: This study shows substantial genetic and unshared environmental influences on carotid intima-media thickness and arterial stiffness and confirms the relevant role of age in the aetiology of these traits. Further support is provided for prevention and health promotion strategies based on modifiable factors.

Pericardial fat, insulin resistance, and left ventricular structure and function in morbid obesity.

BACKGROUND AND AIM: Morbid obesity is often accompanied by insulin resistance and increased ectopic fat surrounding the heart. We evaluated the relation of epicardial and pericardial fat with insulin resistance and left ventricular (LV) structure and function. METHODS AND RESULTS: Epicardial and pericardial fat thicknesses were determined at 2-dimensional echocardiography in 80 morbid obese subjects [age 42 ± 12 years, 31% men, body mass index (BMI) 44.4 ± 7 kg/m(2)]. LV hypertrophy (LV mass ≥51 g/m(2.7)), inappropriately high LV mass for a given cardiac workload (observed vs predicted LV mass >128%), and stress-adjusted LV mid-wall fractional shortening were determined. Pericardial and epicardial fat thicknesses had direct associations with BMI (r = 0.40 and 0.45, both p < 0.01) and waist circumference (r = 0.37 and 0.45, both p < 0.01). Pericardial (partial r = 0.35, p < 0.01), but not epicardial fat thickness (partial r = 0.05, p = n.s.), was correlated with homeostasis model assessment-insulin resistance after adjustment for BMI. Pericardial fat also had a strong negative correlation with mid-wall fractional shortening (p = 0.01) and a positive one with inappropriately high LV mass (p < 0.01), while no such relation was found for epicardial fat (both p = n.s.). Independently of age, male sex, BMI, and anti-hypertensive treatment, pericardial fat thickness had an independent positive association with inappropriately high LV mass (ß = 0.29, p = 0.02), and a negative one with stress-adjusted mid-wall fractional shortening (ß = -0.26, p = 0.04). CONCLUSIONS: Pericardial fat thickness is associated with insulin resistance, inappropriately high LV mass, and LV systolic dysfunction in obese individuals. Findings from this study confirm the existence of a connection between insulin resistance, cardiac ectopic fat deposition and cardiac dysfunction in morbid obesity.

Mutual adaptation of a Faraday instability pattern with its flexible boundaries in floating fluid drops.

Hydrodynamic instabilities are usually investigated in confined geometries where the resulting spatiotemporal pattern is constrained by the boundary conditions. Here we study the Faraday instability in domains with flexible boundaries. This is implemented by triggering this instability in floating fluid drops. An interaction of Faraday waves with the shape of the drop is observed, the radiation pressure of the waves exerting a force on the surface tension held boundaries. Two regimes are observed. In the first one there is a coadaptation of the wave pattern with the shape of the domain so that a steady configuration is reached. In the second one the radiation pressure dominates and no steady regime is reached. The drop stretches and ultimately breaks into smaller domains that have a complex dynamics including spontaneous propagation.

Aortic stiffness and pulse wave reflection in young subjects with migraine: A case-control study.

BACKGROUND: Migraine has been associated with an increased risk for ischemic stroke and other cardiovascular (CV) events, including angina, myocardial infarction, and CV death, but the mechanisms that link migraine to CV disease remain uncertain. We hypothesized that aortic pulse wave velocity (PWV), a direct measure of aortic stiffness and an independent predictor of stroke and CV disease, may be increased in young migraineurs with no overt CV disease or major CV risk factors. METHODS: We studied 60 subjects with migraine (age 33 ± 8 years, 85% women, blood pressure 119/74 ± 11/9 mm Hg) and 60 age-, sex-, and blood pressure-matched healthy control subjects. In all participants, carotid-femoral PWV and aortic augmentation index were determined by applanation tonometry. Cases and controls were free from overt CV disease, diabetes, and major CV risk factors. RESULTS: Subjects with migraine had a higher aortic PWV (7.6 ± 1.2 vs 6.4 ± 1.1 m × s(-1), p < 0.001) and aortic augmentation (heart rate-adjusted augmentation index, 0.17 ± 0.13 vs 0.08 ± 0.15, p < 0.001) than matched control subjects. Migraine patients with aura (n = 17) had higher aortic PWV than those without aura (n = 43; 8.2 ± 1.2 vs 7.4 ± 1.1 m × s(-1), p = 0.027). Age, mean arterial pressure as a measure of distending pressure, and migraine (all p < 0.05) independently predicted aortic PWV when a consistent number of CV risk factors was simultaneously controlled for. CONCLUSIONS: Migraine is independently associated with increased aortic stiffness and enhanced pressure wave reflection. This finding, obtained in young subjects without major CV risk factors, may represent one possible mechanism underlying the increased CV risk in migraine patients.

Lifestyle intervention improves microvascular reactivity and increases serum adiponectin in overweight hypertensive patients.

BACKGROUND AND AIMS: Obesity and hypoadiponectinemia are often associated with high blood pressure. Moreover, microvascular dysfunction is reported to be an early event in patients with hypertension and may be involved in the pathogenesis of organ damage. METHODS AND RESULTS: We investigated the impact of 8-week moderate-intensity aerobic training on adiponectin plasma levels and skin microvascular reactivity in 24 overweight sedentary patients (18 men, age 44+/-6 years, body mass index 28+/-3 kg/m(2)) with never-treated grade 1 essential hypertension. Twenty-four age- and sex-matched hypertensive patients, who were examined twice at 8-week intervals in the absence of exercise training, served as controls. Exercise training was followed by a significant reduction in waist circumference (from 97+/-9 to 95+/-9 cm, p<0.05) and an increase in adiponectin plasma levels (from 11.9+/-3 to 12.5+/-4 mg/L, p<0.05). An inverse correlation was found between adiponectin change and waist circumference change (r=-0.43, p<0.05). The area under the curve after post-occlusive reactive hyperemia at skin laser-Doppler examination increased significantly after aerobic training (from 876+/-539 to 1468+/-925 PU/s, p<0.001). A positive correlation was found between exercise-induced variations of post-occlusive reactive hyperemia and adiponectin plasma levels (r=0.41, p<0.05). Office or 24-h blood pressure values did not change significantly. CONCLUSION: In sedentary overweight patients with mild hypertension, moderate aerobic training improves cutaneous microvascular reactivity and adiponectin plasma levels. These changes precede blood pressure reduction and may serve as biomarkers of the efficacy of non-drug treatment in hypertensive patients.

Endothelial progenitor cells are mobilized after major laparotomic surgery in patients with cancer.

The progression of cancer is largely dependent on neoangiogenesis. Circulating endothelial progenitor cells (EPC) have the ability to form complete vascular structures in vitro and play a crucial role in tumor vasculogenesis. Emerging evidence suggests that surgical injury may induce the mobilization of EPC in animal models, and this might have a negative effect on the prognosis of cancer patients. We studied 20 patients (10 men, 65+/-13 years) undergoing laparotomy for surgical treatment of various forms of abdominal cancer, and 20 age- and sex-matched healthy control subjects. The number of circulating EPC, defined as CD34+/KDR+ cells identified among mononuclear cells isolated from peripheral venous blood, was determined preoperatively and at days 1 and 2 after surgery. Surgery induced a significant increase in circulating EPC levels at day 1 (from 278/mL, interquartile range 171-334, to 558/mL, interquartile range 423-841, p<0.001) and day 2 (709/mL, interquartile range 355-834, p<0.001)compared with baseline values. EPC levels did not change in control subjects. Seven subjects who underwent laparotomic surgery for non-neoplastic disease also showed an increase in EPC levels after surgery (p=0.009 and p=0.028 at day 1 and day 2, respectively). We conclude that patients undergoing elective laparotomic surgery for cancer demonstrate an increase in EPC post-operatively. The potential adverse effects of surgical stress-induced EPC mobilization on tumor and metastasis growth in cancer patients need to be addressed in future studies.

Harvesting peripheral blood progenitor cells from healthy donors with a short course of recombinant human granulocyte-colony-stimulating factor.

A short-course administration of non-glycosylated granulocyte-colony-stimulating factor (G-CSF) was investigated in 68 healthy donors (HDs) in order to collect > or = 4 x 10(6) CD34+ cells per kilogram of recipient's body weight. G-CSF was given at 10 microg/kg per day administered in two divided doses for 3 days. Leukapheresis was scheduled on day 4, 12 h after the last dose of G-CSF. A median of 35.6 circulating CD34+ cells microL(-1) (range, 3.1-185) was found on the day of leukapheresis. This allowed a median collection of CD34+ cells of 4.2 x 10(6) per kilogram of recipient's weight (range, 1.0-17.4). One single procedure was sufficient to reach the target level of CD34+ cells in 36 (53%) of 68 donors; significant correlations were found between the number of CD34+ cells collected on day 4 and the patient's sex, body-weight and volume of blood processed. A retrospective analysis was made with a historical group of HDs collected on day 5. The day 5 schedule allowed a more consistent achievement of the target cell dose with one leukapheresis (P = 0.005) and resulted in the initial collection of a significantly larger number of CD34+ cells (P = 0.006).

[Variation in the composition of Rhodococcus rodochrous GNP-OHP-38r cell membrane fatty acids in response to temperature and salinity]. / Variación de la composición de ácidos grasos de membrana celular de Rhodococcus rodochrous GNP-OHP-38r en respuesta a la temperatura y salinidad.

The members of the genus Rhodococcus are frequent and abundant inhabitants of polluted areas with hydrocarbons and they resist the salinity present in the central Patagonia. This genus has good capacity to eliminate pollution produced by hydrocarbons that constitutes the biggest pollutant agent in the region. The present work studies the answer in the composition of its fatty acids under the combined action of the temperature and saline concentration of an isolated stump of a landfarming system. The strategy of Rhodococcus rodochrous strain GNP-OHP-38r in front of the thermal-osmotic stress is the increase of the percentage of the total saturated fatty acids (n:0); fatty acids branched in the terminal carbon with hidroxyl group in position 2 (n:0 iso 2 OH) and saturated with group methyl in carbon 10 (n:0 10 metil) when the temperature is increased. These acids increase while the percentage of n:1 cis decrease.

[Influence of salinity and temperature on fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane]. / Influencia de la concentración salina y la temperatura en la composición de acidos grasos de membrana de Pseudomonas fluorescens GNP-OHP-3.

The bacteria respond to environmental changes modifying their composition. One of the most important modifications is the variation on fatty acid composition of cellular membranes to maintain the homeoviscosity. The action of temperature, hydrostatic pressure and solvents on Pseudomonas putida has been thoroughly studied. In this paper, the combined action of the temperature and salinity on fatty acid composition of cellular membranes of Pseudomonas fluorescens GNP-OHP-3, a bacterial strain isolated from a petroleum contaminated habitat, was studied. The modifications in the fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane were similar to those described for other members of Pseudomonas: an increase in saturated fatty acids and a decrease in unsaturated fatty acids were observed with the increase of the temperature. Variations of main fatty acids were in general erratic in the range of assayed saline concentrations. The variation of cyclopropane fatty acids could be expressed with mathematic equations that allowed to predict their percentage in relation to sodium chloride concentration.

Variación de la composición de ácidos grasos de membrana celular de Rhodococcus rodochrous GNP-OHP-38r en respuesta a la temperatura y salinidad / Variation in the composition of Rhodococcus rodochrous GNP-OHP-38r cell membrane fatty acids in response to temperature and salinity

Los integrantes del género Rhodococcus son habitantes frecuentes y abundantes de áreas contaminadas con hidrocarburos y resisten la creciente salinidad que se presenta en la Patagonia central. Este género tiene buena capacidad de eliminar contaminantes hidrocarburos que constituyen el mayor contaminante de la región. En el presente trabajo se estudió la respuesta en la composición de sus ácidos grasos de una cepa aislada de un sistema de landfarming, ante la acción combinada de diferentes temperaturas y concentraciones salinas. La estrategia de la cepa Rhodococcus rodochrous GNP-OHP-38r frente al incremento de temperatura, es el aumento del porcentaje de los ácidos grasos saturados totales (n:0); ácidos grasos ramificados en el carbono terminal con grupos oxidrilo en posición 2 (n:0 iso 2 OH) y saturados con grupo metilo en carbono 10 (n:0 10 metil), a expensas de la disminución del porcentaje de los n:1 cis.

The members of the genus Rhodococcus are frequent and abundant inhabitants of polluted areas with hydrocarbons and they resist the salinity present in the central Patagonia. This genus has good capacity to eliminate pollution produced by hydrocarbons that constitutes the biggest pollutant agent in the region. The present work studies the answer in the composition of its fatty acids under the combined action of the temperature and saline concentration of an isolated stump of a landfarming system. The strategy of Rhodococcus rodochrous strain GNP-OHP-38r in front of the thermal-osmotic stress is the increase of the percentage of the total saturated fatty acids (n:0); fatty acids branched in the terminal carbon with hidroxyl group in position 2 (n:0 iso 2 OH) and saturated with group methyl in carbon 10 (n:0 10 metil) when the temperature is increased. These acids increase while the percentage of n:1 cis decrease.

Influencia de la concentración salina y la temperatura en la composición de ácidos grasos de membrana de Pseudomonas fluorescens GNP-OHP-3 / Influence of salinity and temperature on fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane

Las bacterias responden a los cambios ambientales modificando su composición, para evitar el daño que dichos cambios podrían ejercer. Una de las modificaciones más importantes es la variación de la composición de los ácidos grasos de las membranas celulares, que le permite mantener la homeoviscosidad ante situaciones de estrés. Trabajos previos han estudiado la acción de la temperatura, presión hidrostática y diferentes solventes sobre cepas de Pseudomonas putida. En este trabajo se estudió la acción conjunta de la temperatura y la salinidad sobre la composición de ácidos grasos de membranas celulares de Pseudomonas fluorescens GNP-OHP-3, una cepa bacteriana aislada de un hábitat contaminado con petróleo. Pseudomonas fluorescens GNP-OHP-3 respondió a las variaciones de temperatura modificando los ácidos grasos de sus membranas de manera similar a lo descripto en otros integrantes de su género: ante el aumento de temperatura se observó un incremento de ácidos grasos saturados y una disminución de los ácidos grasos insaturados. En el rango de concentraciones salinas ensayadas las variaciones de los ácidos grasos mayoritarios fueron en general erráticas. La respuesta de los ácidos grasos ciclo propano pudo expresarse con ecuaciones matemáticas que permitieron predecir el porcentaje de estos ácidos en relación a la concentración de cloruro de sodio.

The bacteria respond to environmental changes modifying their composition. One of the most important modifications is the variation on fatty acid composition of cellular membranes to maintain the homeoviscosity. The action of temperature, hydrostatic pressure and solvents on Pseudomonas putida has been thoroughly studied. In this paper, the combined action of the temperature and salinity on fatty acid composition of cellular membranes of Pseudomonas fluorescens GNP-OHP-3, a bacterial strain isolated from a petroleum contaminated habitat, was studied. The modifications in the fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane were similar to those described for other members of Pseudomonas: an increase in saturated fatty acids and a decrease in unsaturated fatty acids were observed with the increase of the temperature. Variations of main fatty acids were in general erratic in the range of assayed saline concentrations. The variation of cycle propane fatty acids could be expressed with mathematic equations that allowed to predict their percentage in relation to sodium chloride concentration.

Influencia de la concentración salina y la temperatura en la composición de acidos grasos de membrana de Pseudomonas fluorescens GNP-OHP-3. / [Influence of salinity and temperature on fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane]

The bacteria respond to environmental changes modifying their composition. One of the most important modifications is the variation on fatty acid composition of cellular membranes to maintain the homeoviscosity. The action of temperature, hydrostatic pressure and solvents on Pseudomonas putida has been thoroughly studied. In this paper, the combined action of the temperature and salinity on fatty acid composition of cellular membranes of Pseudomonas fluorescens GNP-OHP-3, a bacterial strain isolated from a petroleum contaminated habitat, was studied. The modifications in the fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane were similar to those described for other members of Pseudomonas: an increase in saturated fatty acids and a decrease in unsaturated fatty acids were observed with the increase of the temperature. Variations of main fatty acids were in general erratic in the range of assayed saline concentrations. The variation of cyclopropane fatty acids could be expressed with mathematic equations that allowed to predict their percentage in relation to sodium chloride concentration.

Variación de la composición de ácidos grasos de membrana celular de Rhodococcus rodochrous GNP-OHP-38r en respuesta a la temperatura y salinidad. / [Variation in the composition of Rhodococcus rodochrous GNP-OHP-38r cell membrane fatty acids in response to temperature and salinity]

The members of the genus Rhodococcus are frequent and abundant inhabitants of polluted areas with hydrocarbons and they resist the salinity present in the central Patagonia. This genus has good capacity to eliminate pollution produced by hydrocarbons that constitutes the biggest pollutant agent in the region. The present work studies the answer in the composition of its fatty acids under the combined action of the temperature and saline concentration of an isolated stump of a landfarming system. The strategy of Rhodococcus rodochrous strain GNP-OHP-38r in front of the thermal-osmotic stress is the increase of the percentage of the total saturated fatty acids (n:0); fatty acids branched in the terminal carbon with hidroxyl group in position 2 (n:0 iso 2 OH) and saturated with group methyl in carbon 10 (n:0 10 metil) when the temperature is increased. These acids increase while the percentage of n:1 cis decrease.

Antimicrobial activity of aqueous extracts and of berberine isolated from Berberis heterophylla.

The antimicrobial activity of Berberis heterophylla leaves, stems and root aqueous extracts was studied in vitro on Gram-positive and Gram-negative bacteria and fungi. The in vitro antifungal activity of berberine isolated from the same source against different Candida species was also investigated.

[Biodegradability of the components of natural hydrocarbon mixtures previously submitted to landfarming]. / Biodegradabilidad de componentes de mezclas naturales de hidrocarburos previamente sometidas a landfarming.

The complex composition of the crude oil and the hydrocarbons that integrate the waste of the different stages of the oil industry turn this product a mixture that presents different difficulties for its elimination by biological methods. The objective of this paper was to study the biodegradation potential of autochthonous bacterial communities on hydrocarbons obtained from four polluted places and subjected to landfarming biorremediation system during a decade. The results showed a marked difference in biodegradability of the three main fractions of crude oil, aliphatic, aromatic, and polar fractions, obtained by column chromatography. All fractions were used as carbon source and energy. There were variations in the production of biomass among the different fractions as well as in the kinetics of biodegradation, according to the composition of each fraction.

Biodegradabilidad de componentes de mezclas naturales de hidrocarburos previamente sometidas a landfarming / Components biodegradability of natural hydrocarbon mixtures previously subjected to landfarming

La compleja composición del petróleo crudo, derivados y deshechos de las diferentes etapas de la industria petrolera hacen de este producto una mezcla que presenta diferentes dificultades para su eliminación por métodos biológicos. El objetivo de este trabajo fue mostrar el potencial de biodegradación de comunidades bacterianas autóctonas frente a hidrocarburos obtenidos de cuatro sitios contaminados y sometidos a biorremediación, en un sistema de Landfarming por casi un década. Los resultados mostraron una marcada diferencia de biodegradabilidad de las tres principales fracciones alifáticas, aromáticas, y polares, obtenidas por cromatografía en columna. Si bien todas las fracciones fueron utilizadas como fuente de carbono y energía, existieron variaciones importantes en la producción de biomasa entre ellas, como asimismo en la cinética de biodegradación, según la composición de cada fracción. (AU)