Obed Garcia | UABJO - Academia.edu (original) (raw)

Papers by Obed Garcia

Obesity Surgery, 2000

Background: Vertical banded gastroplasty (VBG) has been found to result in significant reduction ... more Background: Vertical banded gastroplasty (VBG) has been found to result in significant reduction in body mass index (BMI) during the first postoperative year.We investigated the impact of some intrinsic and extrinsic factors on long-term BMI evolution in morbidly obese patients who underwent VBG, with the aim of establishing a long-term weight-loss prognosis. Methods: 67 consecutive morbidly obese patients who underwent VBG were followed for 2 years; of these, 34 were followed 3 more years, for a total follow-up of 5 years. BMI was monitored and correlated with demographic (preoperative BMI, obese relatives, age and gender) and lifestyle variables (physical activity, habitual dietary transgression and occupational status). Results: Global BMI fell from 47.5 at the time of the intervention to 32.1 when patients were examined 12 months after surgery. From the second year, an upward trend was observed, and at 5 years, mean BMI was above 35, considered in the high-risk range. Modifiable variables affecting lifestyle have shown significantly favorable effects on BMI evolution. Among intrinsic variables, BMI before surgery and obese parents also affect long-term evolution. Conclusion: Different variables should be considered in order to establish a long-term weight-loss prognosis for each patient, thus making it possible to act more specifically on modifiable variables.

Astrophysical Journal, 2009

For distant stars, as observed by the NASA Kepler satellite, parallax information is currently of... more For distant stars, as observed by the NASA Kepler satellite, parallax information is currently of fairly low quality and is not complete. This limits the precision with which the absolute sizes of the stars and their potential transiting planets can be determined by traditional methods. Asteroseismology will be used to aid the radius determination of stars observed during NASA's Kepler mission. We report on the recent asteroFLAG hare-and-hounds Exercise#2, where a group of "hares" simulated data of F-K main-sequence stars that a group of "hounds" sought to analyze, aimed at determining the stellar radii. We investigated stars in the range 9 < V < 15, both with and without parallaxes. We further test different uncertainties in T eff , and compare results with and without using asteroseismic constraints. Based on the asteroseismic large frequency spacing, obtained from simulations of 4 yr time series data from the Kepler mission, we demonstrate that the stellar radii can be correctly and precisely determined, when combined with traditional stellar parameters from the Kepler Input Catalogue. The radii found by the various methods used by each independent hound generally agree with the true values of the artificial stars to within 3%, when the large frequency spacing is used. This is 5-10 times better than the results where seismology is not applied. These results give strong confidence that radius estimation can be performed to better than 3% for solar-like stars using automatic pipeline reduction. Even when the stellar distance and luminosity are unknown we can obtain the same level of agreement. Given the uncertainties used for this exercise we find that the input log g and parallax do not help to constrain the radius, and that T eff and metallicity are the only parameters we need in addition to the large frequency spacing. It is the uncertainty in the metallicity that dominates the uncertainty in the radius.

Obesity Surgery, 2006

Background: The relationship between morbid obesity (MO) and insulin resistance (IR) has been wid... more Background: The relationship between morbid obesity (MO) and insulin resistance (IR) has been widely demonstrated. The euglycemic-hyperglycemic clamp method for diagnosis of IR is neither practical nor cost-effective for population-based studies. However, the application of mathematical models (HOMA, QUICKI and Mffm indices) can be useful. Methods: The data from 171 patients were retrospectively evaluated. We recorded general anthropometric parameters and the basal levels of glucose, triglycerides and insulin and calculated the metabolic indexes both before surgery (Capella gastric bypass) and 6, 12, 24, 36 and 48 months after the operation. Results: Before surgery, patients could be classified according to their waist-hip ratio (WHR) into 2 groups. Group A (n = 131, 108 females and 23 males) with WHR values 1.10 ± 0.1 SD for males and 0.94 ± 0.1 for females (central obesity); and Group B (n = 40, 34 females and 6 males) with WHR values 0.90 ± 0.1 for males and 0.84 ± 0.1 for females (peripheral obesity). Group A patients showed elevated serum levels of glucose, triglycerides and insulin and high values of the HOMA index with low values of QUICKI and Mffm. Group B patients showed lower levels of glucose, triglycerides, insulin and HOMA index and higher values of QUICKI and Mffm. These abnormal levels began to decrease 6 months after bypass and the QUICKI and Mffm began to increase. Conclusions: The high baseline levels of insulin and the high prevalence of hypertension, diabetes or both conditions in patients with central obesity confirm that they suffer a metabolic syndrome, Meanwhile, patients with peripheral obesity with lower levels of chemical parameters and of the metabolic indices suffer peripheral resistance against insulin. Clinical application of these mathematical indices can be useful in patients with MO; they are easily performed and lack the high costs and risks associated with the clamp technique.

Obesity Surgery, 2009

Background The physiological role of apelin in obesity and diabetes remains unclear. Although ape... more Background The physiological role of apelin in obesity and diabetes remains unclear. Although apelin has been studied in persons with different conditions, no studies have yet examined the joint influence of obesity and diabetes on apelin levels. We measured the changes in apelin levels in morbidly obese subjects, with and without diabetes, and in the inverse situation of improvement in carbohydrate metabolism as a result of bariatric surgery. Methods The study was undertaken in 54 morbidly obese persons, 16 of whom had type 2 diabetes mellitus, before and 7 months after undergoing bariatric surgery, and in 12 healthy, nonobese persons. Measurements were made of apelin levels and insulin sensitivity by an intravenous glucose tolerance test. Results The apelin levels in the morbidly obese patients prior to surgery were significantly higher than those of the controls only when the morbidly obese subjects were diabetic (P r = 0.292, P = 0.032) and glucose (r = 0.337, P = 0.039). Bariatric surgery resulted in a significant decrease in apelin levels only in the morbidly obese subjects with impaired fasting glucose or diabetes. The change in apelin levels correlated significantly in the morbidly obese patients with the changes in serum glucose (r = 0.338, P = 0.038) and insulin sensitivity (r = −0.417, P = 0.043). Conclusions This study demonstrates that obesity is not the main determinant of the rise in apelin levels. The association between apelin levels and glucose concentrations and insulin sensitivity provides evidence that apelin may play a role in the pathogenesis of diabetes.

Obesity Surgery, 2005

Background: Resistance to insulin and secondary hyperinsulinemia seem to be the putative link bet... more Background: Resistance to insulin and secondary hyperinsulinemia seem to be the putative link between morbid obesity (MO) and hypertensive disease (HD). Adipose tissue can secrete leptin and angiotensinogen, among other substances. Leptin activates the sympathetic nervous system, leading to HD. Angiotensinogen is a substrate for renin, therefore taking part in the renin-angiotensin-aldosterone axis and the regulation of blood pressure. In MO, both hypertrophy and hyperplasia of the adipocytes lead to an increase in the secretion of both substances, leading to loss of the equilibrium between the levels of both hormones. The aim of the present study was to evaluate these abnormalities and their potential reversibility following bariatric surgery. Methods: Data from 100 patients with MO was retrospectively evaluated. Anthropometric data, the plasma renin activity (PRA), plasma levels of aldosterone, ACE, potassium and sodium were collected both prior to surgery and 6, 12, 24 and 36 months after surgery. Results: The waist-hip ratio (WHR) before surgery allowed classification of our patients in two groups: central obesity (WHR ≥0.90 in men and ≥0.85 in women); peripheral obesity (WHR

Obesity Surgery, 2008

The impact of bariatric surgery on levels of peptide YY (PYY) and ghrelin is still under discussi... more The impact of bariatric surgery on levels of peptide YY (PYY) and ghrelin is still under discussion. We undertook a simultaneous evaluation of the serum changes in PYY and ghrelin depending on the specific type of bariatric surgery. Total PYY and ghrelin were analyzed in 29 healthy persons and in morbidly obese persons undergoing open biliopancreatic diversion (BPD) of Scopinaro (n = 38) or laparoscopic Roux-en-Y gastric bypass (RYGB; n = 13). RYGB resulted in a significantly greater loss of weight and body mass index than BPD. Both RYGB and BPD were associated with a significant increase in PYY, significantly greater for BDP (p = 0.001). Ghrelin rose significantly after RYGB (p = 0.022) but not after BPD. After surgery, PYY correlated positively with weight (r = 0.416, p = 0.009). Ghrelin did not correlate significantly with any of the variables studied. Analysis of variance showed that only the type of surgery contributed significantly to explain the variances in the PYY (p = 0.002) and ghrelin (p = 0.018). BPD results in a greater increase in PYY and a lower weight loss than RYGB. However, only RYGB was associated with a significant increase in ghrelin. The differing weight loss according to the type of bariatric surgery does not seem to be explained by changes arising in PYY and ghrelin.

Obesity Surgery, 2010

Background The prevalence of morbid obesity has seen an increase in developed countries over rece... more Background The prevalence of morbid obesity has seen an increase in developed countries over recent years. Bariatric surgery is almost the only effective strategy for treating super morbidly obese patients. The objective of the study was to evaluate the effects of bariatric surgery on the evolution of the main variables related to diabetes and obesity, especially insulin resistance, parameters of oxidative stress, and inflammatory markers in the early stage after surgery. Methods The study was undertaken in 17 morbidly obese persons who were scheduled for biliopancreatic diversion of Scopinaro. Measurements were made before surgery and 15, 30, 45, and 90 days after surgery. Results We found that significant metabolic changes occurred during the first 90 days after bariatric surgery. The most significant decrease in insulin resistance occurred 15 days after the operation. At this point, the lipid profile and inflammatory and oxidative stress parameters had not improved. One month after surgery, insulin resistance had a parallel evolution to weight and the molecules directly associated with hypertrophic adipose tissue. Conclusions We suggest that there are two mechanisms that contribute to the improvement in insulin resistance after biliopancreatic diversion: on the one hand, a short-term effect related to gastric bypass, and on the other hand, a long-term effect from decreased fat mass and resulting changes in the release of molecules directly associated with hypertrophic adipose tissue.

Hepatology, 2006

The mechanisms responsible for low mitochondrial respiratory chain (MRC) activity in the liver of... more The mechanisms responsible for low mitochondrial respiratory chain (MRC) activity in the liver of patients with nonalcoholic steatohepatitis are unknown. In this study, we examined the cause of this dysfunction in ob/ob mice. Forty-six mice were distributed in six groups: group I: C57BL/6J mice; group II: C57BL/6J Lep(−/−) mice (ob/ob); group III, ob/ob mice treated with manganese [III] tetrakis (5,10,15,20 benzoic acid) porphyrin (MnTBAP); group IV, ob/ob mice treated with IgG1 immunoglobulin; group V, ob/ob mice treated with anti-TNF antibody; group VI: ob/ob mice treated with uric acid. In liver tissue, we measured MRC activity, fatty acid β-oxidation, tumor necrosis factor (TNF), inducible nitric oxide synthase (iNOS), 3-tyrosine-nitrated proteins, 3-tyrosine-nitrated mitochondrial proteins, including cytochrome c and ND4 subunit of complex I. MRC activity was decreased in ob/ob mice. TNF levels, iNOS protein expression, and tyrosine nitrated proteins were markedly increased in the liver of ob/ob mice. In these animals, mitochondrial proteins were markedly tyrosine nitrated, particularly the ND4 subunit of complex I and cytochrome c. Treatment of these animals with uric acid, a peroxynitrite scavenger, anti-TNF antibody, or MnTBAP decreased tyrosine nitrated proteins, improved the activity of MRC complexes, and led to a marked regression of hepatic steatosis and inflammation. In conclusion, MRC dysfunction and liver lesions found in ob/ob mice are likely to reflect the tyrosine nitration of mitochondrial proteins by peroxynitrite or a peroxynitrite-derivate radical. Increased hepatic TNF and iNOS expression might enhance peroxynitrite formation and inhibition of MRC complexes. (HEPATOLOGY 2006;44:581–591.)

Physical Review D, 2010

We combine results from searches by the CDF and D0 collaborations for a standard model Higgs boso... more We combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg->H->W+W- in p=pbar collisions at the Fermilab Tevatron Collider at sqrt{s}=1.96 TeV. With 4.8 fb-1 of integrated luminosity analyzed at CDF and 5.4 fb-1 at D0, the 95% Confidence Level upper limit on \sigma(gg->H) x B(H->W+W-) is 1.75 pb at m_H=120 GeV, 0.38 pb at m_H=165 GeV, and 0.83 pb at m_H=200 GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% Confidence Level a standard-model-like Higgs boson with a mass between 131 and 204 GeV.

Obesity Surgery, 2005

Background: One-Anastomosis Gastric Bypass (OAGB) by laparoscopy consists of constructing a divid... more Background: One-Anastomosis Gastric Bypass (OAGB) by laparoscopy consists of constructing a divided 25-ml (estimated) gastric pouch between the esophago-gastric junction and the crow's foot level, parallel to the lesser curvature, which is anastomosed latero-laterally to a jejunal loop 200 cm distal to the ligament of Treitz. Methods: The results of our first 209 OAGB patients operated from July 2002 to June 2004 are reported. Mean age was 41 years (14-66), BMI 48 (39-86) and mean excess body weight 66 kg (35-220). In 144 patients, OAGB was the only operation performed, and in 61 patients it was accompanied by other surgery (18 cholecystectomies, 5 incisional hernia repairs, and 38 adhesiolysis), and in 4 patients a restrictive bariatric operation had been performed previously. Results: 2 patients (0.9%) were converted to open surgery due to uncontrollable bleeding. 3 patients (1.4%) needed re-operation in the immediate postoperative period. 5 patients (2.3%) needed prolonged hospital stay due to acute pancreatitis in 1 and anastomotic leakage in 4, all resolving with conservative treatment. 2 patients died (0.9%), 1 from fulminant pulmonary thromboembolism and 1 from nosocomial pneumonia. Long-term complications have occurred in only 2 patients who developed clinically significant iron-deficiency anemia. Mean excess weight loss was 75% after 1 year and >80% at 2 years. Conclusion: OAGB is a simple, safe and effective operation with less perioperative risk than conventional gastric bypass, quicker return to normal activities, and better quality of life.

European Journal of Clinical Microbiology & Infectious Diseases, 2009

The resurgence of tuberculosis (TB) in western countries has been attributed to the HIV epidemic,... more The resurgence of tuberculosis (TB) in western countries has been attributed to the HIV epidemic, immigration and drug resistance. Multi-drug-resistant tuberculosis (MDR-TB) is due to the transmission of MDR Mycobacterium tuberculosis strains in new cases, or to selection of single-drug resistant strains induced by previous treatment. The aim of this report is to determine risk factors for MDR-TB in Europe. Methods A systematic review was conducted of published reports of risk factors associated with MDR-TB in Europe. Meta-analysis, meta-regression and sub-grouping were used to pool risk estimates of MDR-TB and analyse associations with age, gender, immigrant status, HIV status, occurrence year, study design and area of Europe. Results Twenty-nine papers were eligible for the review from 123 identified in the search. The pooled risk of MDR-TB was 10.23 times higher in previously treated than in never-treated cases, with wide heterogeneity between studies. Study design and geographical area were associated with MDR-TB risk estimates in previously treated patients, which in turn was higher in cohort studies carried-out in western Europe (RR=12.63;) than in eastern Europe (RR=8.53;95%CI=6.57-11.06). National estimates were possible for 6 countries. MDR-TB cases were more likely to be foreign-born (OR=2.46;95%CI=1.86-3.24), younger than 65 years (OR=2.53;95%CI=1.74-4.83), male (OR=1.38;95%CI=1.16-1.65), and HIV-positive (OR=3.52; 95%CI=2.48-5.01).

Tropical Animal Health and Production, 1983

This study was conducted at Carimagua Research Centre in a high savanna area in the eastern plain... more This study was conducted at Carimagua Research Centre in a high savanna area in the eastern plains of Colombia. The objectives were to identify the pathogenic parasites prevalent in the area and to study their seasonal variations and ecological conditions for use in planning control measures. The calves from two groups of 50 cows each (zebu crossbred) were used. Group I calves were born at the beginning of the rainy season and Group II calves later in the same period. The highest faecal egg counts observed were of trichostrongylid eggs. In necropsied animalsCooperia had high populations followed byHaemonchus. Throughout the rainy season there were favourable conditions for development and transmission of calf nematodes; animals born towards the end of the rainy season developed a lower infestation level which is probably easier to control. The animals were particularly susceptible to infestation with gastro-intestinal parasites at weaning. From these observations and in view of the relatively low stocking rate and the sequential burning of the savanna it is suggested that deworming be done at eight and 18 months of age. Cette étude a été effectuée au Centre de Recherche de Carimagua dans une zone de savane située dans les plaines orientales de Colombie. On s'est efforcé d'identifier les parasites pathogenès les plus répandus dans la zone et d'étudier leur variation saisonnière et leur écologie afin de mettre au point des mesures de lutte. Dex veaux provenant de deux groupes de 50 vaches chacun (métis zébus) ont été utilisés. Les veaux du groupe I étaient nés au début de la saison des pluies et les veaux du groupe II étaint nés quand cette même saison était plus avancée. Lors des examens coprologiques le nombre des oeufs de trichostrongylidés était le plus élevé. Lors des autopsies, les populations deCooperia étaint les plus élevées, survies par lesHaemonchus. Tout au long de la saison des pluies les conditions étaient favorables au développement et à la transmission des nématodes du veau; les animaux nés vers la fin de la saison des pluies présentaient un niveau d'infestation plus faible, ce qui en rend le contrôle plus facile. Les animaux étaient particulièrement susceptible à l'infestation par les parasites gastro-intestinaux lors du sevrage. A partir de ces observations et au vu du taux de charge relativement bas et du brûlage programmé de la savane, il est proposé de pratiquer la vermifugation à l'âge de 8 et de 18 mois. Este estudio se llevó a cabo en la Estación Experimental de Carimagua, en los Llanos Orientales de Colombia. Los objetivos fueron el identificar las especies de parásitos prevalentes en el área y estudiar las variaciones estacionales ecológicas para establecer un plan de control. Se utilizaron entonces dos grupos de terneros provenientes de dos hatos de cincuenta vacas cada uno (cruces de Cebú). Los animales del grupo I nacieron al principio de la estación lluviosa y los del II al final de la misma. Los conteos más altos correspondieron a huevos de trichostróngilus. En los animales en los cuales se les practicó la necropsia, se encontró una población alta deCooperia seguida deHaemonchus. Durante la estación lluviosa, las condiciones fueron favorables para el desarrollo y transmisión de nemátodos; los animales que nacieron al final de la estación presentaron niveles más bajos de infestación. Todos los animales fueron particularmente sensibles a la infestación al destete. Con base en estas observaciones y en vista de la baja rata de pastoreo por unidad de superficie, y las quemas periódicas de las praderas, se recomienda vermifugar a los animales a los 8 y 18 meses de edad.

Obesity Surgery, 2010

Background The storage capacity of adipose tissue may be an important factor linking obesity, ins... more Background The storage capacity of adipose tissue may be an important factor linking obesity, insulin resistance (IR), and associated morbidities. The aim of this study was to analyze the expression of lipogenic and lipolytic genes in adipose tissue and the influence of IR. Methods We studied the mRNA expression of peroxisome proliferator-activated receptor-γ (PPARγ) and lipogenic and lipolytic enzymes in the visceral (VAT) and subcutaneous adipose tissue (SAT) from 23 morbidly obese patients (MO; 13 with low IR and ten with high IR) and from 15 healthy, lean controls. Results In the VAT and SAT from the MO, we found an increased expression of PPARγ (p = 0.001 and p = 0.022, respectively), acyl-coenzyme A (CoA)/cholesterol acyltransferase (p p p p = 0.003), and adipose triglyceride lipase (p p p = 0.004 and p CoA synthetase, however, was significantly lower in the MO with high IR (p p = 0.010), hormone-sensitive lipase (p p = 0.006) were only significantly increased in VAT. Acyl-CoA synthetase (p = 0.012) and fatty acid binding protein-4 (p = 0.003) were only significantly decreased in SAT. The expression of the genes studied was only greater in the SAT than the VAT in the controls. Conclusion Our results show an upregulation of genes facilitating triglyceride/fatty acid cycling and a reduction in the genes involved in de novo synthesis of fatty acids in morbid obesity. The expression of some of the genes studied seems to be related with the state of IR. VAT and SAT differ metabolically and also between controls and MO.

This paper presents the PI-OBS algorithm, a parallel-iterative scheduler for OBS nodes. Conventio... more This paper presents the PI-OBS algorithm, a parallel-iterative scheduler for OBS nodes. Conventional schemes are greedy in the sense that they process headers one by one. In PI-OBS, all the headers received during a given time window are jointly processed to optimize the delay and output wavelength allocation, applying void filling techniques, and allowing traffic differentiation. Results show a similar or better performance than the LAUC-VF algorithm, commonly used as a performance bound for OBS schedulers. The PI-OBS scheduler has been designed to allow parallel electronic implementation similar to the ones in VOQ schedulers, with a deterministic response time.

Obesity Surgery, 2000

Background: Vertical banded gastroplasty (VBG) has been found to result in significant reduction ... more Background: Vertical banded gastroplasty (VBG) has been found to result in significant reduction in body mass index (BMI) during the first postoperative year.We investigated the impact of some intrinsic and extrinsic factors on long-term BMI evolution in morbidly obese patients who underwent VBG, with the aim of establishing a long-term weight-loss prognosis. Methods: 67 consecutive morbidly obese patients who underwent VBG were followed for 2 years; of these, 34 were followed 3 more years, for a total follow-up of 5 years. BMI was monitored and correlated with demographic (preoperative BMI, obese relatives, age and gender) and lifestyle variables (physical activity, habitual dietary transgression and occupational status). Results: Global BMI fell from 47.5 at the time of the intervention to 32.1 when patients were examined 12 months after surgery. From the second year, an upward trend was observed, and at 5 years, mean BMI was above 35, considered in the high-risk range. Modifiable variables affecting lifestyle have shown significantly favorable effects on BMI evolution. Among intrinsic variables, BMI before surgery and obese parents also affect long-term evolution. Conclusion: Different variables should be considered in order to establish a long-term weight-loss prognosis for each patient, thus making it possible to act more specifically on modifiable variables.

Astrophysical Journal, 2009

For distant stars, as observed by the NASA Kepler satellite, parallax information is currently of... more For distant stars, as observed by the NASA Kepler satellite, parallax information is currently of fairly low quality and is not complete. This limits the precision with which the absolute sizes of the stars and their potential transiting planets can be determined by traditional methods. Asteroseismology will be used to aid the radius determination of stars observed during NASA's Kepler mission. We report on the recent asteroFLAG hare-and-hounds Exercise#2, where a group of "hares" simulated data of F-K main-sequence stars that a group of "hounds" sought to analyze, aimed at determining the stellar radii. We investigated stars in the range 9 < V < 15, both with and without parallaxes. We further test different uncertainties in T eff , and compare results with and without using asteroseismic constraints. Based on the asteroseismic large frequency spacing, obtained from simulations of 4 yr time series data from the Kepler mission, we demonstrate that the stellar radii can be correctly and precisely determined, when combined with traditional stellar parameters from the Kepler Input Catalogue. The radii found by the various methods used by each independent hound generally agree with the true values of the artificial stars to within 3%, when the large frequency spacing is used. This is 5-10 times better than the results where seismology is not applied. These results give strong confidence that radius estimation can be performed to better than 3% for solar-like stars using automatic pipeline reduction. Even when the stellar distance and luminosity are unknown we can obtain the same level of agreement. Given the uncertainties used for this exercise we find that the input log g and parallax do not help to constrain the radius, and that T eff and metallicity are the only parameters we need in addition to the large frequency spacing. It is the uncertainty in the metallicity that dominates the uncertainty in the radius.

Obesity Surgery, 2006

Background: The relationship between morbid obesity (MO) and insulin resistance (IR) has been wid... more Background: The relationship between morbid obesity (MO) and insulin resistance (IR) has been widely demonstrated. The euglycemic-hyperglycemic clamp method for diagnosis of IR is neither practical nor cost-effective for population-based studies. However, the application of mathematical models (HOMA, QUICKI and Mffm indices) can be useful. Methods: The data from 171 patients were retrospectively evaluated. We recorded general anthropometric parameters and the basal levels of glucose, triglycerides and insulin and calculated the metabolic indexes both before surgery (Capella gastric bypass) and 6, 12, 24, 36 and 48 months after the operation. Results: Before surgery, patients could be classified according to their waist-hip ratio (WHR) into 2 groups. Group A (n = 131, 108 females and 23 males) with WHR values 1.10 ± 0.1 SD for males and 0.94 ± 0.1 for females (central obesity); and Group B (n = 40, 34 females and 6 males) with WHR values 0.90 ± 0.1 for males and 0.84 ± 0.1 for females (peripheral obesity). Group A patients showed elevated serum levels of glucose, triglycerides and insulin and high values of the HOMA index with low values of QUICKI and Mffm. Group B patients showed lower levels of glucose, triglycerides, insulin and HOMA index and higher values of QUICKI and Mffm. These abnormal levels began to decrease 6 months after bypass and the QUICKI and Mffm began to increase. Conclusions: The high baseline levels of insulin and the high prevalence of hypertension, diabetes or both conditions in patients with central obesity confirm that they suffer a metabolic syndrome, Meanwhile, patients with peripheral obesity with lower levels of chemical parameters and of the metabolic indices suffer peripheral resistance against insulin. Clinical application of these mathematical indices can be useful in patients with MO; they are easily performed and lack the high costs and risks associated with the clamp technique.

Obesity Surgery, 2009

Background The physiological role of apelin in obesity and diabetes remains unclear. Although ape... more Background The physiological role of apelin in obesity and diabetes remains unclear. Although apelin has been studied in persons with different conditions, no studies have yet examined the joint influence of obesity and diabetes on apelin levels. We measured the changes in apelin levels in morbidly obese subjects, with and without diabetes, and in the inverse situation of improvement in carbohydrate metabolism as a result of bariatric surgery. Methods The study was undertaken in 54 morbidly obese persons, 16 of whom had type 2 diabetes mellitus, before and 7 months after undergoing bariatric surgery, and in 12 healthy, nonobese persons. Measurements were made of apelin levels and insulin sensitivity by an intravenous glucose tolerance test. Results The apelin levels in the morbidly obese patients prior to surgery were significantly higher than those of the controls only when the morbidly obese subjects were diabetic (P r = 0.292, P = 0.032) and glucose (r = 0.337, P = 0.039). Bariatric surgery resulted in a significant decrease in apelin levels only in the morbidly obese subjects with impaired fasting glucose or diabetes. The change in apelin levels correlated significantly in the morbidly obese patients with the changes in serum glucose (r = 0.338, P = 0.038) and insulin sensitivity (r = −0.417, P = 0.043). Conclusions This study demonstrates that obesity is not the main determinant of the rise in apelin levels. The association between apelin levels and glucose concentrations and insulin sensitivity provides evidence that apelin may play a role in the pathogenesis of diabetes.

Obesity Surgery, 2005

Background: Resistance to insulin and secondary hyperinsulinemia seem to be the putative link bet... more Background: Resistance to insulin and secondary hyperinsulinemia seem to be the putative link between morbid obesity (MO) and hypertensive disease (HD). Adipose tissue can secrete leptin and angiotensinogen, among other substances. Leptin activates the sympathetic nervous system, leading to HD. Angiotensinogen is a substrate for renin, therefore taking part in the renin-angiotensin-aldosterone axis and the regulation of blood pressure. In MO, both hypertrophy and hyperplasia of the adipocytes lead to an increase in the secretion of both substances, leading to loss of the equilibrium between the levels of both hormones. The aim of the present study was to evaluate these abnormalities and their potential reversibility following bariatric surgery. Methods: Data from 100 patients with MO was retrospectively evaluated. Anthropometric data, the plasma renin activity (PRA), plasma levels of aldosterone, ACE, potassium and sodium were collected both prior to surgery and 6, 12, 24 and 36 months after surgery. Results: The waist-hip ratio (WHR) before surgery allowed classification of our patients in two groups: central obesity (WHR ≥0.90 in men and ≥0.85 in women); peripheral obesity (WHR

Obesity Surgery, 2008

The impact of bariatric surgery on levels of peptide YY (PYY) and ghrelin is still under discussi... more The impact of bariatric surgery on levels of peptide YY (PYY) and ghrelin is still under discussion. We undertook a simultaneous evaluation of the serum changes in PYY and ghrelin depending on the specific type of bariatric surgery. Total PYY and ghrelin were analyzed in 29 healthy persons and in morbidly obese persons undergoing open biliopancreatic diversion (BPD) of Scopinaro (n = 38) or laparoscopic Roux-en-Y gastric bypass (RYGB; n = 13). RYGB resulted in a significantly greater loss of weight and body mass index than BPD. Both RYGB and BPD were associated with a significant increase in PYY, significantly greater for BDP (p = 0.001). Ghrelin rose significantly after RYGB (p = 0.022) but not after BPD. After surgery, PYY correlated positively with weight (r = 0.416, p = 0.009). Ghrelin did not correlate significantly with any of the variables studied. Analysis of variance showed that only the type of surgery contributed significantly to explain the variances in the PYY (p = 0.002) and ghrelin (p = 0.018). BPD results in a greater increase in PYY and a lower weight loss than RYGB. However, only RYGB was associated with a significant increase in ghrelin. The differing weight loss according to the type of bariatric surgery does not seem to be explained by changes arising in PYY and ghrelin.

Obesity Surgery, 2010

Background The prevalence of morbid obesity has seen an increase in developed countries over rece... more Background The prevalence of morbid obesity has seen an increase in developed countries over recent years. Bariatric surgery is almost the only effective strategy for treating super morbidly obese patients. The objective of the study was to evaluate the effects of bariatric surgery on the evolution of the main variables related to diabetes and obesity, especially insulin resistance, parameters of oxidative stress, and inflammatory markers in the early stage after surgery. Methods The study was undertaken in 17 morbidly obese persons who were scheduled for biliopancreatic diversion of Scopinaro. Measurements were made before surgery and 15, 30, 45, and 90 days after surgery. Results We found that significant metabolic changes occurred during the first 90 days after bariatric surgery. The most significant decrease in insulin resistance occurred 15 days after the operation. At this point, the lipid profile and inflammatory and oxidative stress parameters had not improved. One month after surgery, insulin resistance had a parallel evolution to weight and the molecules directly associated with hypertrophic adipose tissue. Conclusions We suggest that there are two mechanisms that contribute to the improvement in insulin resistance after biliopancreatic diversion: on the one hand, a short-term effect related to gastric bypass, and on the other hand, a long-term effect from decreased fat mass and resulting changes in the release of molecules directly associated with hypertrophic adipose tissue.

Hepatology, 2006

The mechanisms responsible for low mitochondrial respiratory chain (MRC) activity in the liver of... more The mechanisms responsible for low mitochondrial respiratory chain (MRC) activity in the liver of patients with nonalcoholic steatohepatitis are unknown. In this study, we examined the cause of this dysfunction in ob/ob mice. Forty-six mice were distributed in six groups: group I: C57BL/6J mice; group II: C57BL/6J Lep(−/−) mice (ob/ob); group III, ob/ob mice treated with manganese [III] tetrakis (5,10,15,20 benzoic acid) porphyrin (MnTBAP); group IV, ob/ob mice treated with IgG1 immunoglobulin; group V, ob/ob mice treated with anti-TNF antibody; group VI: ob/ob mice treated with uric acid. In liver tissue, we measured MRC activity, fatty acid β-oxidation, tumor necrosis factor (TNF), inducible nitric oxide synthase (iNOS), 3-tyrosine-nitrated proteins, 3-tyrosine-nitrated mitochondrial proteins, including cytochrome c and ND4 subunit of complex I. MRC activity was decreased in ob/ob mice. TNF levels, iNOS protein expression, and tyrosine nitrated proteins were markedly increased in the liver of ob/ob mice. In these animals, mitochondrial proteins were markedly tyrosine nitrated, particularly the ND4 subunit of complex I and cytochrome c. Treatment of these animals with uric acid, a peroxynitrite scavenger, anti-TNF antibody, or MnTBAP decreased tyrosine nitrated proteins, improved the activity of MRC complexes, and led to a marked regression of hepatic steatosis and inflammation. In conclusion, MRC dysfunction and liver lesions found in ob/ob mice are likely to reflect the tyrosine nitration of mitochondrial proteins by peroxynitrite or a peroxynitrite-derivate radical. Increased hepatic TNF and iNOS expression might enhance peroxynitrite formation and inhibition of MRC complexes. (HEPATOLOGY 2006;44:581–591.)

Physical Review D, 2010

We combine results from searches by the CDF and D0 collaborations for a standard model Higgs boso... more We combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg->H->W+W- in p=pbar collisions at the Fermilab Tevatron Collider at sqrt{s}=1.96 TeV. With 4.8 fb-1 of integrated luminosity analyzed at CDF and 5.4 fb-1 at D0, the 95% Confidence Level upper limit on \sigma(gg->H) x B(H->W+W-) is 1.75 pb at m_H=120 GeV, 0.38 pb at m_H=165 GeV, and 0.83 pb at m_H=200 GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% Confidence Level a standard-model-like Higgs boson with a mass between 131 and 204 GeV.

Obesity Surgery, 2005

Background: One-Anastomosis Gastric Bypass (OAGB) by laparoscopy consists of constructing a divid... more Background: One-Anastomosis Gastric Bypass (OAGB) by laparoscopy consists of constructing a divided 25-ml (estimated) gastric pouch between the esophago-gastric junction and the crow's foot level, parallel to the lesser curvature, which is anastomosed latero-laterally to a jejunal loop 200 cm distal to the ligament of Treitz. Methods: The results of our first 209 OAGB patients operated from July 2002 to June 2004 are reported. Mean age was 41 years (14-66), BMI 48 (39-86) and mean excess body weight 66 kg (35-220). In 144 patients, OAGB was the only operation performed, and in 61 patients it was accompanied by other surgery (18 cholecystectomies, 5 incisional hernia repairs, and 38 adhesiolysis), and in 4 patients a restrictive bariatric operation had been performed previously. Results: 2 patients (0.9%) were converted to open surgery due to uncontrollable bleeding. 3 patients (1.4%) needed re-operation in the immediate postoperative period. 5 patients (2.3%) needed prolonged hospital stay due to acute pancreatitis in 1 and anastomotic leakage in 4, all resolving with conservative treatment. 2 patients died (0.9%), 1 from fulminant pulmonary thromboembolism and 1 from nosocomial pneumonia. Long-term complications have occurred in only 2 patients who developed clinically significant iron-deficiency anemia. Mean excess weight loss was 75% after 1 year and >80% at 2 years. Conclusion: OAGB is a simple, safe and effective operation with less perioperative risk than conventional gastric bypass, quicker return to normal activities, and better quality of life.

European Journal of Clinical Microbiology & Infectious Diseases, 2009

The resurgence of tuberculosis (TB) in western countries has been attributed to the HIV epidemic,... more The resurgence of tuberculosis (TB) in western countries has been attributed to the HIV epidemic, immigration and drug resistance. Multi-drug-resistant tuberculosis (MDR-TB) is due to the transmission of MDR Mycobacterium tuberculosis strains in new cases, or to selection of single-drug resistant strains induced by previous treatment. The aim of this report is to determine risk factors for MDR-TB in Europe. Methods A systematic review was conducted of published reports of risk factors associated with MDR-TB in Europe. Meta-analysis, meta-regression and sub-grouping were used to pool risk estimates of MDR-TB and analyse associations with age, gender, immigrant status, HIV status, occurrence year, study design and area of Europe. Results Twenty-nine papers were eligible for the review from 123 identified in the search. The pooled risk of MDR-TB was 10.23 times higher in previously treated than in never-treated cases, with wide heterogeneity between studies. Study design and geographical area were associated with MDR-TB risk estimates in previously treated patients, which in turn was higher in cohort studies carried-out in western Europe (RR=12.63;) than in eastern Europe (RR=8.53;95%CI=6.57-11.06). National estimates were possible for 6 countries. MDR-TB cases were more likely to be foreign-born (OR=2.46;95%CI=1.86-3.24), younger than 65 years (OR=2.53;95%CI=1.74-4.83), male (OR=1.38;95%CI=1.16-1.65), and HIV-positive (OR=3.52; 95%CI=2.48-5.01).

Tropical Animal Health and Production, 1983

This study was conducted at Carimagua Research Centre in a high savanna area in the eastern plain... more This study was conducted at Carimagua Research Centre in a high savanna area in the eastern plains of Colombia. The objectives were to identify the pathogenic parasites prevalent in the area and to study their seasonal variations and ecological conditions for use in planning control measures. The calves from two groups of 50 cows each (zebu crossbred) were used. Group I calves were born at the beginning of the rainy season and Group II calves later in the same period. The highest faecal egg counts observed were of trichostrongylid eggs. In necropsied animalsCooperia had high populations followed byHaemonchus. Throughout the rainy season there were favourable conditions for development and transmission of calf nematodes; animals born towards the end of the rainy season developed a lower infestation level which is probably easier to control. The animals were particularly susceptible to infestation with gastro-intestinal parasites at weaning. From these observations and in view of the relatively low stocking rate and the sequential burning of the savanna it is suggested that deworming be done at eight and 18 months of age. Cette étude a été effectuée au Centre de Recherche de Carimagua dans une zone de savane située dans les plaines orientales de Colombie. On s'est efforcé d'identifier les parasites pathogenès les plus répandus dans la zone et d'étudier leur variation saisonnière et leur écologie afin de mettre au point des mesures de lutte. Dex veaux provenant de deux groupes de 50 vaches chacun (métis zébus) ont été utilisés. Les veaux du groupe I étaient nés au début de la saison des pluies et les veaux du groupe II étaint nés quand cette même saison était plus avancée. Lors des examens coprologiques le nombre des oeufs de trichostrongylidés était le plus élevé. Lors des autopsies, les populations deCooperia étaint les plus élevées, survies par lesHaemonchus. Tout au long de la saison des pluies les conditions étaient favorables au développement et à la transmission des nématodes du veau; les animaux nés vers la fin de la saison des pluies présentaient un niveau d'infestation plus faible, ce qui en rend le contrôle plus facile. Les animaux étaient particulièrement susceptible à l'infestation par les parasites gastro-intestinaux lors du sevrage. A partir de ces observations et au vu du taux de charge relativement bas et du brûlage programmé de la savane, il est proposé de pratiquer la vermifugation à l'âge de 8 et de 18 mois. Este estudio se llevó a cabo en la Estación Experimental de Carimagua, en los Llanos Orientales de Colombia. Los objetivos fueron el identificar las especies de parásitos prevalentes en el área y estudiar las variaciones estacionales ecológicas para establecer un plan de control. Se utilizaron entonces dos grupos de terneros provenientes de dos hatos de cincuenta vacas cada uno (cruces de Cebú). Los animales del grupo I nacieron al principio de la estación lluviosa y los del II al final de la misma. Los conteos más altos correspondieron a huevos de trichostróngilus. En los animales en los cuales se les practicó la necropsia, se encontró una población alta deCooperia seguida deHaemonchus. Durante la estación lluviosa, las condiciones fueron favorables para el desarrollo y transmisión de nemátodos; los animales que nacieron al final de la estación presentaron niveles más bajos de infestación. Todos los animales fueron particularmente sensibles a la infestación al destete. Con base en estas observaciones y en vista de la baja rata de pastoreo por unidad de superficie, y las quemas periódicas de las praderas, se recomienda vermifugar a los animales a los 8 y 18 meses de edad.

Obesity Surgery, 2010

Background The storage capacity of adipose tissue may be an important factor linking obesity, ins... more Background The storage capacity of adipose tissue may be an important factor linking obesity, insulin resistance (IR), and associated morbidities. The aim of this study was to analyze the expression of lipogenic and lipolytic genes in adipose tissue and the influence of IR. Methods We studied the mRNA expression of peroxisome proliferator-activated receptor-γ (PPARγ) and lipogenic and lipolytic enzymes in the visceral (VAT) and subcutaneous adipose tissue (SAT) from 23 morbidly obese patients (MO; 13 with low IR and ten with high IR) and from 15 healthy, lean controls. Results In the VAT and SAT from the MO, we found an increased expression of PPARγ (p = 0.001 and p = 0.022, respectively), acyl-coenzyme A (CoA)/cholesterol acyltransferase (p p p p = 0.003), and adipose triglyceride lipase (p p p = 0.004 and p CoA synthetase, however, was significantly lower in the MO with high IR (p p = 0.010), hormone-sensitive lipase (p p = 0.006) were only significantly increased in VAT. Acyl-CoA synthetase (p = 0.012) and fatty acid binding protein-4 (p = 0.003) were only significantly decreased in SAT. The expression of the genes studied was only greater in the SAT than the VAT in the controls. Conclusion Our results show an upregulation of genes facilitating triglyceride/fatty acid cycling and a reduction in the genes involved in de novo synthesis of fatty acids in morbid obesity. The expression of some of the genes studied seems to be related with the state of IR. VAT and SAT differ metabolically and also between controls and MO.

This paper presents the PI-OBS algorithm, a parallel-iterative scheduler for OBS nodes. Conventio... more This paper presents the PI-OBS algorithm, a parallel-iterative scheduler for OBS nodes. Conventional schemes are greedy in the sense that they process headers one by one. In PI-OBS, all the headers received during a given time window are jointly processed to optimize the delay and output wavelength allocation, applying void filling techniques, and allowing traffic differentiation. Results show a similar or better performance than the LAUC-VF algorithm, commonly used as a performance bound for OBS schedulers. The PI-OBS scheduler has been designed to allow parallel electronic implementation similar to the ones in VOQ schedulers, with a deterministic response time.