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Biomedical subjects

A Cuevas

Publications and source records attributed to A Cuevas.

17 recordsLinked to original sources
PubMed2004

Image quality and dose evaluation in spiral chest CT examinations of patients with lung carcinoma.

A study was undertaken to assess the quality of general chest CT examinations for indication of lung carcinoma according to the criteria proposed in the European Commission (EC) Guidelines, and to investigate their usefulness in the optimization of this practice. The criteria were evaluated for a sample of 100 examinations from five radiology departments in the Madrid area featuring single slice helical CT scanners with special emphasis on radiation dose and image quality. To determine the degree of compliance with the image criteria considered, the examinations were independently evaluated twice by five radiologists from the participating centres. A subsequent selection of the observers was made according to the consistency and independence of their readings. Dose measurements carried out in parallel supplied data to estimate the values of the CT dose indices (CTDI), dose-length product (DLP) and effective dose (E). The results show good compliance with the image criteria used - between 93% and 98% on average at the different sites, with variable degrees of internal deviation. 10 out of a total of 16 criteria proposed in the EC guidelines were met by practically all the examinations in the sample. The average weighted CTDI (CTDI(w)) values per site were in the range of 13-19 mGy; those of DLP were between 263 mGy cm and 577 mGy cm, and those of effective dose between 4 mSv and 9 mSv. The highest mean DLP value was below but close to the reference value proposed in the EC Document (650 mGy cm). In general, a weak correlation or no correlation at all was found between image quality scores and patient dose (DLP).

Humans↗
PubMed2003

Mediterranean diet, but not red wine, is associated with beneficial changes in primary haemostasis.

OBJECTIVE: (1) To compare the effect of an alcohol-free Mediterranean-type diet (MD) and a high-fat diet (HFD) on variables of primary haemostasis (bleeding time, plasma von Willebrand factor and platelet aggregation/secretion). (2) To test whether red wine supplementation modified these variables, independently of the diet. DESIGN, SUBJECTS AND INTERVENTION: Controlled prospective intervention study. Two groups, each consisting of 21 healthy male university students (22+/-3.4 y), received either MD or HFD during 90 days. Between days 30 and 60, both diets were supplemented with 240 ml/day of red wine. Baseline (T0) and T30, T60 and T90-day samples were drawn. Bleeding time was measured before (day 30) and after (day 60) wine supplementation. No drop out from the study was experienced. SETTING: University campus and outpatient nutrition clinic. RESULTS: All baseline (day 0) variables did not differ significantly between study groups. On day 30, individuals on MD had significantly higher levels of plasma beta-carotene, folate, ascorbate, and eicosapentaenoic acid in plasma lipid fractions, than those on HFD. Total plasma cholesterol, HDL and LDL did not change significantly in either study group at any time point. After 30 days on each diet, individuals on MD had longer bleeding time (BT) than those on HFD (7.6+/-2.8 vs 5.8+/-1.7 min; P=0.017). BT did not change significantly after I month of wine supplementation (7.1+/-2.0 vs 5.5+/-2.0 min, respectively). Plasma von Willebrand factor (vWF : Ag) on day 0 was 89+/-40 and 111+/-70% in MD and HFD groups, respectively (P=0.21). These values did not change significantly at 30, 60 or 90 days. MD intake was associated with an increase in platelet serotonin secretion (P=0.02) and a marginal increase in platelet aggregation after stimulation with epinephrine (P=0.07). Wine intake resulted in a marginal decrease in platelet (14)C-5-HT secretion with 4 micro M ADP (P=0.07). However, both platelet aggregation and secretion were consistently increased when using collagen as agonist (1 and 2 micro g/ml, P=0.01). CONCLUSION: The longer BT in individuals on MD, obtained independently of red wine, denotes less interaction of platelets with the vascular wall, which could be beneficial from the point of view of cardiovascular (CV) risk. This effect is not explained by changes in the measured haemostatic determinants of BT (plasma vWF, ex vivo platelet function), and might be attributed to other as yet unknown vascular factors. Moderate consumption of red wine results in a significant increase in ex vivo platelet aggregation and secretion after stimulation with collagen. This observation contradicts previous reports, although further studies are required to elucidate the influence of this finding on CV risk.

Adult↗
PubMed2001

Complementary effects of Mediterranean diet and moderate red wine intake on haemostatic cardiovascular risk factors.

OBJECTIVES: To compare the effect of alcohol-free Mediterranean-type diet (MD) and high-fat diet (HFD) on plasma concentration of emergent haemostatic cardiovascular risk factors (HCVRF). Also, to test if red wine supplementation modifies HCVRF, independent of diet. DESIGN, SUBJECTS AND INTERVENTION: Controlled prospective intervention study. Two groups, each of 21 healthy male university students (22+/-3.4 y), received either MD or HFD for 90 days. Between days 30 and 60, both diets were supplemented with 240 ml/day of red wine. Baseline and T30, T60 and T90-day samples were drawn. No drop out from the study was observed. SETTING: University campus and outpatient nutrition clinic. RESULTS: Volunteers on HFD at T30 had increases in pro-coagulants fibrinogen (22%), factor VIIc (9%), and factor VIIIc (4%), and decreases in natural anticoagulants antithrombin III (3%), protein C (11%) and protein S (6%) and of 20% in plasminogen activator inhibitor-1. At the same time, individuals on MD had increases in fibrinogen (4%), antithrombin III (5%), protein C (3%), protein S (2.7%), and decreases in factor VIIIc (9%), and plasminogen activator inhibitor-1 (21%). After adjusting by baseline values, MD was associated with lower plasma fibrinogen (P=0.03), factor VIIc (P=0.034) and factor VIIIc (P=0.0057) and with higher levels of protein S (P=0.013). Red wine supplementation, in both diets, resulted in decreased plasma fibrinogen (P=0.001) and factor VIIc (P=0.05), and increased tissue plasminogen activator antigen (P=0.01) and plasminogen activator inhibitor-1 antigen (P=0.0003). Wine consumption was also associated with significantly (P=0.01) divergent effects on antithrombin III: it decreased by 10% in individuals on HFD but increased slightly in those on MD. No effects of diet or wine were detected in plasma protein C and C-reactive protein. CONCLUSION: MD and moderate consumption of red wine have complementary, mostly beneficial effects on HCVRF.

Adult↗
PubMed2001

[Differences in plasma antioxidants according to socioeconomic level in Chilean women].

BACKGROUND: Free radical-mediated oxidative damage is a known initial event in atherogenesis. Cardiovascular disease is frequent in the Chilean population showing differences in the prevalence of risk factors of the disease according to socioeconomic level (SEL). AIM: To determine levels of antioxidants and lipid peroxides in Chilean women from different SEL. PATIENTS AND METHODS: Blood samples were taken from 81 women for measurements of plasma ascorbic acid, beta-carotene, alpha-tocopherol, licopene, ubiquinol, glutathione, total plasma antioxidant capacity, and lipid peroxides (TBARS). RESULTS: Individuals in the lower SEL showed reduced levels of plasma beta-carotene, ascorbic acid, alpha-tocopherol, and ubiquinol compared to women in the higher SEL. There were no differences between groups in the plasma levels of glutathione, total antioxidant capacity, or TBARS. CONCLUSIONS: The results could be explained in part by the higher consumption of fruits and vegetables in women from the upper SEL.

Adult↗
PubMed2000

Cardiovascular risk factors in vegetarians. Normalization of hyperhomocysteinemia with vitamin B(12) and reduction of platelet aggregation with n-3 fatty acids.

Hyperhomocysteinemia in association with vitamin B(12) deficiency, and increased platelet aggregation, probably due to dietary lack of n-3 fatty acids, constitute cardiovascular risk factors frequently observed in vegetarians. We tested if administration of vitamin B(12) normalizes the concentration of total plasma homocysteine, and if intake of eicosapentaenoic (20:5n-3) and docosahexaenoic (22:6n-3) fatty acids modulates platelet function in a population of lactoovovegetarians. One week after a single intramuscular injection of cyanocobalamin (10000 microg) in 18 individuals, serum vitamin B(12) increased from 149+/-63 pg/mL to 532+/-204 pg/mL (p<0.0001) and total tHcy dropped from 12.4+/-4.7 to 7.9+/-3.1 micromol/L (p<0. 0001). Ten of fourteen of these vegetarians completed an 8-week supplementation with 700 mg/day of each eicosapentaenoic and docosahexaenoic acids. Increased incorporation of these fatty acids into plasma lipids was observed in all of them, together with a significant reduction in maximum percentage or slope of platelet aggregation with all the agonists tested (ADP, epinephrin, collagen, arachidonic acid). No significant change in bleeding time was observed after n-3 fatty acid trial. Supplementation with vitamin B(12) and n-3 fatty acids corrects hyperhomocysteinemia and reduces platelet reactivity to agonists in vegetarians. Whether this supplementation improves the already reduced cardiovascular morbidity and mortality associated with vegetarian diet has yet to be demonstrated.

Adult↗
PubMed2000

[Endothelial dysfunction as a primary disorder in vascular diseases].

Endothelium controls vascular smooth muscle tone by secreting relaxing and contracting factors. There is a constant release of endothelium derived relaxing factors, mainly nitric oxide, a potent vasodilator, inhibitor of platelet aggregation, monocyte adhesion and smooth muscle proliferation. In addition, the endothelium may increase the release of NO in response to humoral stimulation by vasoactive substances such as acetylcholine, bradykinin or substance P. Although the endothelium releases a number of products, no single blood test has yet proved useful to determine normal endothelial function or as early abnormalities. The most useful test of endothelial function relies on the measurement of endothelium-dependent dilatation in response to pharmacological or physiologic stimuli. The alteration of this response is known as endothelial dysfunction and has been observed in a variety of circumstances related to cardiovascular risk. This review summarizes the evidence that sustains this association and emphasizes the clinical utility of assessing endothelial function presenting two clinical cases of hypercholesterolemia in which a high-resolution vascular ultrasound in the brachial artery was used.

Adult↗
PubMed1999

Plasma polyphenols and antioxidants, oxidative DNA damage and endothelial function in a diet and wine intervention study in humans.

An intervention study was performed to evaluate the influence of a Mediterranean diet, a high fat diet, and their supplementation with red wine in moderate amounts, on biochemical, physiological, and clinical parameters related to atherosclerosis and other chronic diseases. For 3 months two groups of 21 male volunteers each, received either a Mediterranean diet or a high fat diet; during the second month, red wine was added isocalorically, 240 ml/day. Participants were kept under close medical and nutritional surveillance. At days 0, 30, 60 and 90, clinical, physiological and biochemical evaluations were made. Plasma vitamin C was significantly decreased in the high fat diet group compared to the Mediterranean diet group. After wine supplementation to the Mediterranean diet, a significant 13.5% increase in plasma vitamin C was observed. Furthermore, when wine was added vitamin E decreased significantly in plasma, 15% in the high fat diet and 26% in the Mediterranean diet. Total plasma antioxidant capacity (total antioxidant reactivity) increased 28% above basal levels in the Mediterranean diet group, but not in the high fat diet group. In both groups, wine induced a marked increase in total antioxidant reactivity above basal levels, 56% and 23%, respectively. Oxidative DNA damage, detected as 8-hydroxydeoxyguanosine (8-OHdG) levels in blood leukocyte DNA, was markedly increased by the high fat diet; however, it was strongly reduced, to approximately 50% basal values, after wine supplementation, both in the high fat diet and Mediterranean diet groups. Endothelial function, evaluated noninvasively as flow-mediated vascular reactivity of the brachial artery, was suppressed by the high fat diet, and was normal after wine supplementation. These effects are attributed to oxidative stress associated with a high fat diet, and to the elevated plasma antioxidant capacity associated with wine consumption and the Mediterranean diet. The results presented support the following conclusions: a high fat diet induces oxidative stress; a diet rich in fruits and vegetables enhances antioxidant defenses; wine supplementation to a high fat or a Mediterranean diet increases plasma antioxidant capacity, decreases oxidative DNA damage, and normalizes endothelial function.

Adult↗
PubMed1999

Vegetarians and cardiovascular risk factors: hemostasis, inflammatory markers and plasma homocysteine.

We studied hemostatic and inflammatory cardiovascular risk factors (CVRF), and total plasma homocysteine (tHcy) in 26 vegetarians (23 lacto- or ovolactovegetarians and 3 vegans), matched by age, sex and socioeconomic status with omnivorous controls. Vegetarians had significantly lower proportion of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in plasma lipids, significantly shortened bleeding time, and increased blood platelet count and in vitro platelet function (aggregation and secretion). Plasma levels of all coagulation or fibrinolytic factors and natural inhibitors synthesized in the liver were lower in vegetarians than in controls. Whereas for some factors this decrease was statistically significant (fibrinogen, factor VIIc, antithrombin III, protein S, plasminogen) for the remaining (factors VIIIc, Vc, prothrombin, protein C) a trend in the same direction was found. For hemostatic proteins of predominantly extrahepatic origin (von Willebrand factor. tPA, PAI-1) this tendency was not present. No significant differences in inflammatory proteins (C-reactive protein and alpha1-protease inhibitor) were detected in both groups. tHcy was significantly increased in vegetarians, and correlated only with cobalamin levels. The increased platelet function and tHcy found in vegetarians may counteract the known cardiovascular health benefits of vegetarian diet (VD).

Adult↗
PubMed1998

[Dyslipidemias in renal diseases: pathogenesis and treatment].

Patients with renal diseases like nephrotic syndrome, chronic renal failure (uremia) and renal transplantation frequently present disturbances of lipid metabolisms, however their pathogenesis is partially understood. Moreover, cardiovascular diseases are responsible for many deaths in these patients. Although the effect of the dyslipidemias in the development of atherosclerosis in renal diseases is not clear, they probably play a role. Since actually the survival of these patients is substantial, it is important to manage them appropriately with regard to their dyslipidemias. This review will examine the pathogenesis and treatment of dyslipidemias in patients with nephrotic syndrome, chronic renal failure and renal transplantation.

Humans↗
PubMed1993

International cooperation in analytical chemistry: experience of antidoping control at the XI Pan American Games.

We describe the experience of the international cooperation carried out for antidoping control at the XI Pan American Games. A temporary accreditation was granted by the International Olympic Committee to the accredited laboratory of Barcelona (Spain) to set up a Doping Control Laboratory in Havana. Two other laboratories from Mexico and Cuba contributed personnel, materials, and instrumentation. The main issues associated with the preparation and organization of the project are described. During 16 days, 741 urine samples were tested for stimulants, narcotics, anabolic steroids, beta-blockers, diuretics, cannabinoids, local anesthetics, and human chorionic gonadotropin by gas-liquid chromatography, gas chromatography/mass spectrometry, high-performance liquid chromatography, and immunoassay techniques. Analytical methodologies, quality-control strategies, and the main results are reported.

Acebutolol↗
PubMed1992

Wiedemann-Beckwith syndrome: clinical, cytogenetical and radiological observations in 39 new cases.

Thirty-nine patients (82% under 1 year of age) with Wiedemann-Beckwith syndrome (WBS) were prospectively studied. To evaluate the somatometric data the normal range was set out at mean +/- 2 SD. The relevant physical findings were a characteristic face, non increased mean height and weight, normal head circumference, defective abdominal wall, a predominance of the upper segment, and tibial bowing. Mental retardation was documented in 5 cases but in only 1 it was related to hypoglycemia. The 32 cases karyotyped were normal. Since neonatal hypoglycemia is frequent (34.3% in our series) and potentially deleterious for the CNS we propose to monitor the glycemia every 6 h during the first 3 days in WBS newborns in order to correct glycemia below of 2.6 mmol/l (46.8 mg/dl) according to recent studies. The comparison with previous large series enabled us to precise the frequency, onset and evolution of the main stigmata.

Adolescent↗
PubMed1979

Malformed genitalia in the 47,XYY genotype.

A 5 10/12 year-old boy with a 47,XYY karyotype, micropenis, scrotal hypospadias and right testicular regression is described. Normal for age basal plasma testosterone levels which increased after hCG stimulation were interpreted as an adequate response of the left testicular Leydig cells. The review of similar cases did not permit definite conclusions concerning the relationship between the abnormal genitalia and the XYY karyotype.

Aneuploidy↗
PubMed1978

Effect of indomethacin on CO2-induced hyperaemia (CO2-response) in the rabbit brain.

It was studied in rabbits whether indomethacin, a prostaglandin-synthesis inhibitor, influences cerebral hyperaemia induced by inhalation of carbon dioxide (CO2-response). The aim of this experiment was to show whether prostaglandins are involved in the regulation of cerebral vascular tone. The animals were repeatedly ventilated with a CO2-room air mixture before and after the injection of indomethacin solution. Regional cerebral blood flow in one hemisphere was continously measured using a thermo-clearance method. In 10 out of 13 rabbits no effect of indomethacin on the CO2 response could be observed. In the other 3 animals a reduction of the CO2-response only occurred in the 15-45 minutes interval after the indomethacin injection. The authors, however, do not exclude the possibility of this reduction being an artefact. The reasons are discussed.

Animals↗
PubMedDate not supplied

[Quality assessment in single-slice spiral brain CT examinations of patients with cerebrovascular accident].

OBJECTIVES: Our objective was to apply quality criteria proposed by the European Commission (EC) Guidelines to the brain CT examinations for cerebrovascular accident (CVA) diagnosis at single-slice spiral CT scanners from five different hospitals in the Madrid area. MATERIAL AND METHODS: A sample of 100 brain CT examinations was collected and independently reviewed by five radiologists, to determine the degree of fulfilment of image quality criteria. Dose measurements were performed to estimate the values of the CT dose indexes (CTDIw, CTDIair), the dose length product (DLP), and the effective dose (E). RESULTS: Once the McNemar test was applied to the sample, the number of observers' readings was reduced to three. The quality criteria were, in general, fulfilled, since mean values of image quality score between 80% and 92% were deduced, with variation coefficients per centre in the range of 0.07-0.1. However, both visualization criteria 1.1.2 and 1.1.3 exhibited similar ranges of fulfilment (38% - 94%). The good compliance with critical reproduction criteria in the study reflected the capability of these CT scanners to create images of adequate quality, although optimisation should be achieved in some of the centres. Concerning radiation exposure, the mean values per centre of the dose quantities were in the range of 42-64 mGy for the weighted CTDI (CTDIw), 423-744 mGy x cm for DLP, and 1.1-1.9 mSv for E. CONCLUSIONS: The mean values at three centres were close to but above the reference value proposed by the EC Guidelines for CTDIw (60 mGy), and lower than the corresponding reference level for DLP (1050 mGy x cm). Dose optimisation techniques focused on the adjustment of the CTDIw-related examination parameters were proposed.

Humans↗
PubMedDate not supplied

[Dental survey of Down syndrome patients. Reflections and synthesis].

This article presents a work made in year 1990 in the Asociación Odontológica Argentina, in a population of 192 persons with Down's Syndrome. The results were controlled with other Group (Control Group), taken as reference, same number of people, sex and age, not Down's Syndrome diagnostic. Age between 3 and 26 years-old. The examination evaluates: dental caries occurrence, filling and lost teeth, oral hygiene, diet and type of dental treatment received. The report illustrates the differences between the dental health care and dental treatment, in the population with Down's Syndrome and the control Group. The author calls the attention to dental profession to colaborate in the dental health care of Down's Syndrome population.

Adolescent↗
PubMedDate not supplied

Computed tomography in abdominal Castleman's disease.

Three patients with abdominal Castleman disease studied by CT are presented. Two cases corresponded to localized mesenteric disease and the third to a systemic form of the process. The CT findings are nonspecific, although a dense enhancement of the lesions can be demonstrated sometimes on dynamic CT.

Adult↗