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S Quevedo

Publications and source records attributed to S Quevedo.

13 recordsLinked to original sources
PubMed1999

Brown adipose tissue response to cafeteria diet-feeding involves induction of the UCP2 gene and is impaired in female rats as compared to males.

Noradrenaline-dependent brown adipose tissue (BAT) thermogenesis is activated by the cold and excess energy intake, largely depends on the activity of the uncoupling protein 1 (UCP1), and is mediated mainly through the beta3-adrenoceptor (beta3-AR). We investigated the expression of ucp2, a gene that encodes a putative UCP1-like uncoupling protein, along with that of ucp1 and beta3-ar, in the interscapular BAT (IBAT) of male and female rats chronically fed a cafeteria diet. After 3 months on this diet, male rats attained a 34% excess body mass and showed IBAT hypertrophy and increased IBAT thermogenic potential, in terms of both UCP1 and UCP2 mRNA expression (both by 1.6-fold), UCP1 protein expression (by 1.75-fold) and GDP binding to IBAT mitochondria (by 2.2-fold); female rats attained a larger excess body weight (50%) and their IBAT, although hypertrophied, showed no signs of increased thermogenic potential per gram of tissue. Interestingly, the IBAT of female rats was already activated compared to males. Treatment of mouse brown adipocytes in primary culture with noradrenaline also triggered a dose-dependent increase of the levels of UCP1 mRNA and UCP2 mRNA. Retroregulatory down-regulation of the beta3-AR mRNA levels was found in the two models used. The results support a physiological role for UCP2, along with UCP1, in rodent BAT thermogenesis.

Adipose Tissue, Brown↗
PubMed1999

Glucose erythrocyte transporter in women with breast cancer: changes in lipid composition of erythrocyte membrane.

Women with breast cancer show altered blood glucose compartmentation compared with healthy women, with lower concentrations in plasma and similar concentrations in blood cells. The goal of this paper was to study whether this pattern was the result of changes in the erythrocyte glucose transporter and, if so, to assess the possible changes in lipid environment of the erythrocyte membrane. In 12 women with different degrees of breast cancer and 12 age-matched healthy women, the lipid composition of erythrocyte membrane and erythrocyte glucose transport were studied. Women with breast cancer showed changes in both the kinetic variables and the lipid environment of the glucose transporter, in keeping with an increase in fluidity of the erythrocyte membrane. The results obtained would account, in part, for the changes in glucose compartmentation.

Aged↗
PubMed1998

Sex-associated differences in cold-induced UCP1 synthesis in rodent brown adipose tissue.

The effects of acute and chronic acclimation to cold on uncoupling protein 1 (UCP1) levels, as well as on GDP-binding to mitochondria, cytochrome c oxidase activity and mitochondrial protein concentration in brown adipose tissue (BAT) of intact male and female rats have been analyzed. Results reveal that females rats are more sensitive to cold because their threshold temperature for the thermogenic response is set at a higher value (around 22 degreesC) than that of males (around 18 degreesC), hence leading to differences in BAT UCP1 levels between the sexes at different environmental temperatures. In vitro experiments showed that steroid hormones, beta-estradiol, estrone and progesterone, can reduce norepinephrine-induced UCP1 synthesis in brown adipocytes differentiated in primary culture. Thus the different sex-associated response of cold-induced thermogenesis in rats does not appear to be explained by a direct action of sex steroids upon the adipocyte, implying that other factors in the thermogenic regulatory system must be involved.

Adipose Tissue, Brown↗
PubMed1996

Changes induced by fasting and dietetic obesity in thermogenic parameters of rat brown adipose tissue mitochondrial subpopulations.

The effects of starvation on the thermogenic parameters of three different mitochondrial subpopulations in brown adipose tissue (BAT) of both post-cafeteria obese and lean rats were investigated. Tissue from different BAT depots from fed and 24 h starved rats were collected, pooled and three mitochondrial subpopulations were isolated by differential centrifugation; the M1 fraction (1000 g), the M3 fraction (3000 g) and the M15 fraction (15,000 g). Thermogenic parameters were measured in the three mitochondrial subtypes, and uncoupling protein (UCP) mRNA was determined in BAT. The results showed that starvation induced a decrease in mitochondrial turnover in BAT from both lean and obese rats. Moreover, a selective net loss of UCP from the lightest mitochondrial fraction (M15) in lean rats, with a concomitant reduction of UCP mRNA was observed. The reductions did not occur in obese rats and, as a result, a change in UCP distribution between the mitochondrial subpopulations was produced, with an increase in the M1 mitochondrial subtype. The lack of response of UCP to starvation observed in BAT of obese rats compared with the decrease seen in lean animals, is a consequence of a different mitochondrial subpopulation composition and/or a different response of a particular subpopulation to starvation.

Adipose Tissue, Brown↗
PubMed1995

Amplifying dinucleotide microsatellite loci from bone and tooth samples of up to 5000 years of age: more inconsistency than usefulness.

We have studied the feasibility of using dinucleotide-repeat microsatellites in the analysis of DNA from ancient bones and teeth. We have used three microsatellites (IVS8CA, IVS17BTA, and IVS17BCA) within the cystic fibrosis transmembrane conductance regulator gene in 28 DNA samples from bones and teeth of up to 5000 years of age. PCR amplification was successful in 71.4% of cases. The repeated analysis of each marker produced different genotypes in 97% of samples, and the same individual genotype was reproduced at least once in 45.5% of cases. Alleles differing from the originals consisted of additions or deletions of 1-39 dinucleotides. The mechanism by which alleles differing from the originals were amplified can be related to the marked degradation of the DNA, with repeat sequences of different length interacting with the partially degraded repeats of the amplified loci. The repeated analysis of each sample allowed us to produce data with some anthropological interest. Among the haptotypes detected in samples from Easter Island, two (16-32-13 and 23-32-13) were found in more than one sample. Similarly, three haplotypes (16-7-17, 16-7-13, and 16-24-13) were detected more than once in samples from the Basque Country. Although haplotypes in the Basque Country are amongst the commonest in European chromosomes, most of those detected in the Easter Island samples are not frequent in Europeans. Thus, the repeated typing of microsatellites allowed us to postulate the genotypes that might be present in the samples but dinucleotide markers do not seem to be reliable enough for genotyping ancient bone and teeth samples.

Base Sequence↗
PubMed1995

[Traumatic hemothorax treated by video-assisted thoracoscopic surgery].

The introduction of video-assisted thoracic surgery (VTS) has significantly furthered the use of the thoracoscope in surgery. In the case we describe, a 79-years-old man at high risk for surgery came to our hospital with hemothorax due to trauma. The necessary procedure was performed successfully with VTS, which allowed for the repair of an acute condition that would otherwise have been treated conventionally by way of posterolateral thoracotomy. We conclude that VTS may play an important role in the diagnosis and treatment of certain thoracic injuries, so that surgery involving more extensive bleeding is rendered unnecessary.

Accidental Falls↗
PubMed1994

Extended cervical mediastinoscopy: prospective study of fifty cases.

To assess the usefulness of extended cervical mediastinoscopy (ECM) in the staging of bronchogenic carcinoma, an ECM was performed prospectively in 50 patients with bronchogenic carcinoma of the left lung. The ECM was used after evaluation of disease operability and computed tomographic findings, and was performed simultaneously with standard cervical mediastinoscopy. In ECM, using the same cervical incision as in a standard cervical mediastinoscopy, dissection is performed behind the anterior face of the sternum. The aortic arch is reached at the level of the origin of the innominate artery. The mediastinoscope is then passed by sliding it along the left anterolateral face of the aortic arch until it reaches the aortopulmonary window. Extended cervical mediastinoscopy was considered positive when a nodal biopsy result consistent with a neoformative process or direct invasion of the mediastinal structures was found. Four patients with positive standard cervical mediastinoscopy and negative ECM were excluded. A false negative ECM was defined as the presence of infiltrated adenopathies at the paraaortic level detected on postoperative histologic study. The ECM was positive in 5 patients in whom operation was contraindicated. Resectability in the remaining 41 patients was 97.6%. Postoperative pathologic study showed infiltrated adenopathy in 3 patients (2 subcarinal, 1 subaortic) accounting for 40 true negatives (the subcarinal group is inaccessible by ECM). This study suggests that ECM has outstanding specificity (100%), sensitivity of 83.3%, and a diagnostic accuracy of 97.8%. A positive predictive value of 100% and a negative predictive value of 97.5% were also identified by this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Experimental tracheal revascularization with omentum.

We assessed omental revascularization of heterotopic tracheal implants in rats, and investigated the influence of factors that can enhance revascularization. The trachea of the donor animal was excised in two parts, and each tracheal allograft was implanted in the omentum of two recipients. The influence of mechanical factors was evaluated by applying traction at both ends of the graft with and without drainage of the tracheal lumen, and the influence of pharmacologic factors by giving cefonicid, hydrocortisone, cefonicid plus hydrocortisone, or cyclosporine and azathioprine during the postoperative period. Revascularization of the graft from the omentum with preservation of the tracheal structure was established. Graft viability showed significant differences between the tracheal implants to which no traction had been applied and those with traction at both ends. Tracheal allografts from animals receiving immunosuppressants were completely viable and no significant differences were found between the controls and animals in this group.

Animals↗
PubMed1984

Microevolution in prehistoric Andean populations: chronologic nonmetrical cranial variation in northern Chile.

Multivariate distance statistics were computed from 14 nonmetrical cranial variables among five prehistoric samples representing steps in the microevolutionary history of a coastal population in northern Chile. Roughly 70% of nonmetrical cranial variation was found to be explained by chronologic distance covering a period of 6,500 years. This estimate is similar to a previous one derived from craniometric data. Implications of these findings are briefly discussed.

Adult↗
PubMed1982

Microevolution in prehistoric Andean populations: I. Chronologic craniometric variation.

Mahalanobis D2 statistics (with size and shape components) were computed for nine craniometric variables among five prehistoric groups representing steps in the microevolutionary history of a coastal population in Northern Chile. Roughly 80% of craniometric variation was found to be explained by chronologic distance covering a period of roughly 6500 years. Kinship decreases in this population at a relatively constant rate of 8.6 X 10(-5) per year.

Biological Evolution↗
PubMedDate not supplied

[Primary spontaneous pneumothorax. A retrospective study of 495 cases].

We conducted a retrospective study of patients treated in our department for primary spontaneous pneumothorax (PSP) between 1986 and 1993. The 495 patients were between 12 and 81 years old (mean 28.2 years). Four hundred fifteen (83.8%) were men and 80 (16.2%) were women. PSP was in the right lung in 262 cases (52.9%) and in the left lung in 215 (43.5%). Both sides were affected in 18 cases (3.6%). The initial treatment was pleural drainage; small caliber drains were used in 85 and no associated complications were observed. On 185 occasions (37.3%), patients required surgical repair as a result of air leaks, recurrence or acute hemorrhage. There were postsurgical complications in 15 cases (8.1%) but no recurrences or deaths after surgery. We observed no significant differences in the number of recurrences after use of conventional drains or small caliber drains. Nor were there differences in mean time of hospital stay or complications after conventional surgery or video assisted surgery, a technique that has only recently been introduced. We conclude that PSP responds well to treatment with pleural drains and that small caliber catheters offer a good alternative for treating first episodes. Surgery is indicated when there is recurrence or when air leaks are persistent. At present, video assisted thoracoscopic surgery has successfully replaced axillary thoracotomy for most patients.

Adolescent↗