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Biomedical subjects

David Prieto

Publications and source records attributed to David Prieto.

9 recordsLinked to original sources
PubMed2006

Maternal polymorphisms 677C-T and 1298A-C of MTHFR, and 66A-G MTRR genes: is there any relationship between polymorphisms of the folate pathway, maternal homocysteine levels, and the risk for having a child with Down syndrome?

This study was aimed at analyzing the effect of mutations in three non-synonymous SNP genes (677C > T and 1298A > C of the methylenetetrahydrofolate reductase (MTHFR) gene, and 66A > G in the MTRR gene) on total plasmatic homocysteine (Hcy), in 91 mothers of Down syndrome (DS) infants and 90 control mothers. The comparison of both groups of mothers is a new way to determine if those mutations and their interactions increase the risk for DS. Material came from the case-control network of the Spanish Collaborative Study of Congenital Malformations (ECEMC). Using a general lineal model in a backwards step, we performed the analyses including the different mutations, maternal age, the fact that each mother had a DS or a control infant, and all possible interactions of these variables, in the models, being maternal Hcy the continuous dependent variable. In another model, maternal folic acid intake during the third trimester of pregnancy was added. The results from both models were essentially the same: Hcy levels variability differs from case mothers to control ones, the presence of the MTHFR1298A > C polymorphism also affects significantly the Hcy variance, as it does the statistical interaction between the mutations MTRR66A > G and MTHFR1298A > C in the mother. In this sense, the interaction between different polymorphisms may totally modify their individual effects, and some of those effects are different in mothers of DS children and in controls' mothers. For instance, only two mutations in MTRR66 (GGAA) in mothers of control infants increase the reference maternal Hcy level in 4.66 units, and the individual effect of the genotype with only two mutations in the MTHFR1298 gene (AACC) increases the reference Hcy level in 12.74 units. However, the presence of the four mutations (GGCC) interacts giving a statistically significant decrease in 6.00 units in the level of Hcy in control mothers. On the contrary, in mothers of DS infants, the sole presence of two mutations in one of these two genes decreases the levels of Hcy (-2.31 units for GGAA genotype, and -3.43 units for AACC genotype), while the presence of the four mutations (GGCC) increases Hcy in 9.53 units. Taking into consideration that in the one-carbon metabolism cystathionine beta-synthase (CBS) catalyzes Hcy in an irreversible way, and that CBS gene is located in chromosome 21, fetuses and infants with DS have functional folate deficiency due to overexpression of CBS. This fact, as well as others influencing Hcy levels (such as nutrients interactions and lifestyle), together with the fetal genotype, suggest that their relationship with DS could be through an effect on fetal survival up to birth. Three possible mechanisms are considered by evaluating the results in the light of the present knowledge on cytology and molecular biology.

Case-Control Studies↗
PubMed2006

Negative signs and symptoms secondary to antipsychotics: a double-blind, randomized trial of a single dose of placebo, haloperidol, and risperidone in healthy volunteers.

OBJECTIVE: Despite the clinical observation that antipsychotics can produce negative symptoms, no previous controlled study, to our knowledge, has evaluated this action in healthy subjects. The present study assessed observer-rated and self-rated negative symptoms produced by conventional and second-generation antipsychotics in healthy volunteers. METHOD: The authors used a double-blind, placebo-controlled trial of single doses of haloperidol (5 mg) and risperidone (2.5 mg) in normal subjects. Thirty-two subjects were administered haloperidol, risperidone, and placebo in a random order. Motor variables and observer-rated negative symptoms were assessed after 3-4 hours and subjective negative symptoms and drowsiness after 24 hours. RESULTS: Neither of the active drugs caused significant motor extrapyramidal symptoms after administration. Haloperidol caused significantly more negative signs and symptoms than placebo on the Scale for the Assessment of Negative Symptoms (SANS) and two self-rated negative symptom scales: the Subjective Deficit Syndrome Scale total score and an analog scale that evaluates subjective negative symptoms. Risperidone caused significantly more negative signs and symptoms than placebo on the Brief Psychiatric Rating Scale (BPRS), the SANS, the Subjective Deficit Syndrome Scale total score, and the analog scale for subjective negative symptoms. After control for drowsiness, risperidone but not haloperidol produced more negative symptoms than placebo on the BPRS and the SANS. Significance was lost for the subjective negative symptoms with both drugs. CONCLUSIONS: Single doses of both haloperidol and risperidone produce negative symptoms in normal individuals. Drowsiness may be an important confounding factor in the assessment of negative symptoms in antipsychotic trials.

Adolescent↗
PubMed2005

[Acute aortic dissection].

Acute aortic dissection is a relatively common pathology, which is related to the high incidence of arterial hypertension observed in some population subgroups. It is accompanied by a high mortality rate if not treated immediately. Early diagnosis is relatively simple but depends on a high index of suspicion. Its etiopathogenesis is related to cystic medial necrosis. In the majority of cases, the aortic wall is abnormal along its entire length. Surgery is indicated in virtually all type A dissections, with involvement of the ascending aorta, and in many type B dissections, characterized by isolated involvement of the descending aorta. In the majority of the latter, however, medical therapy appears to lead to better results than surgery, but in recent times, treatment has been revolutionized by the use of stents. Surgery is rarely curative. Hence, long-term follow-up (probably for life) is essential. This includes strict control of arterial hypertension and monitoring of the untreated aortic segments, and especially any residual patent false lumen, which is observed in the majority of cases, in order to prevent rupture and to minimize the consequences of the formation of false aneurysms.

Acute Disease↗
PubMed2004

Secular decreasing trend of the frequency of hypospadias among newborn male infants in Spain.

BACKGROUND: The frequency of hypospadias is not uniform worldwide. Several countries have reported an increase in its frequency at birth. Although a better ascertainment of the minor forms has been considered as an explanation, the potential effect of environmental endocrine disrupters has also been proposed. We studied the secular trend of hypospadias in Spain over the past 22 years, separating the minor and major forms. METHODS: We used data from the Spanish Collaborative Study of Congenital Malformations (ECEMC) registry, analyzing the frequency in two different periods: from 1978 to 1995, and from 1996 to 2002. To evaluate the "step" of the frequency between the two periods, we applied a parametric Student's t-test, and the nonparametric Mann-Whitney rank test. RESULTS: The birth frequency of isolated and total hypospadias was quite stable between 1978 and 1995. In 1996, it decreased dramatically in a step, essentially due to isolated cases with minor forms of hypospadias. Study of the geographical distribution by the 17 Spanish regions showed that the frequency step occurred in nearly all of them. CONCLUSIONS: It is difficult to consider that the observed decrease of the frequency of minor forms of hypospadias could be due to less accurate reporting of these minor forms in all 87 hospitals in the same year without any previous physician agreement. This decrease rather suggests a change in some product or exposure affecting the whole country. We think that the observed change in the frequency cannot be attributable to a lower exposure to endocrine disrupters or the voluntary interruption of gestation.

Geography↗
PubMed2004

Renal dysfunction after myocardial revascularization.

OBJECTIVES: In this study, we evaluate the incidence of and analyse the pre and intraoperative risk factors for the development of postoperative renal dysfunction (PRD), and the impact of such an event on perioperative mortality and on hospital length of stay. In addition, we sought to investigate the influence of a mildly increased serum creatinine (1.3-2.0 mg/dl) on perioperative mortality and morbidity. METHODS: The study included 2445 consecutive patients who had no pre-existing renal disease (creatinine or=2.1 mg/dl with a preoperative-to-postoperative increase >or=0.9 mg/dl. Univariate and multivariate analyses were performed where appropriate. RESULTS: Global 30-day mortality was 0.7%. The incidence of PRD was 5.6% (136 patients). Mortality for patients who experienced PRD was 8.8 vs. 0.1% for patients who did not (P<0.001). PRD increased the length of hospital stay by 3.4 days (7.6 vs. 11.0 days; P<0.001), and patients who needed haemodialysis (11%) had a perioperative mortality of 33.3% and a mean hospital length of stay of 16 days. Multivariable logistic regression identified the following variables as independent predictors of PRD: age (P=0.017; odds ratio (OR) 1.3 per 10 years), angina class III/IV (P=0.003; OR 1.7); cardiopulmonary bypass time (P=0.007; OR 1.01 per minute); preoperative serum creatinine levels: group 1 (1.3-1.6 mg/dl (P<0.001; OR 5.5)) and group 2 (1.7-2.0 mg/dl (P<0.001; OR 14.2)). Finally, a mild elevation of the preoperative creatinine level (1.3-2.0 mg/dl) increased significantly the probability of perioperative mortality, low cardiac output, haemodialysis and prolonged hospital stay. CONCLUSIONS: Although the likelihood of PRD in patients without pre-existing renal dysfunction is relatively low, it dramatically increases mortality, morbidity and length of stay after CABG. Mildly elevated (>1.2 mg/dl) preoperative serum creatinine level significantly increases the perioperative mortality and morbidity.

Aged↗
PubMed2004

Circadian rhythms of dopamine, glutamate and GABA in the striatum and nucleus accumbens of the awake rat: modulation by light.

Using microdialysis, we investigated the circadian rhythms of the extracellular concentrations of dopamine, glutamate and gamma-aminobutyric acid (GABA) in the striatum and nucleus accumbens of the awake rat. Wistar rats were maintained in a 12 hr dark:12 hr light (12:12) cycle for 2 wk before the experiment began. The neurotransmitter levels were measured every 30 min for 30 hr in control (maintaining the 12:12 cycle) or in experimental conditions under a 24-h light period (continuous light) or under a 24-h dark interval (continuous dark). The dopamine metabolites, DOPAC and HVA, and the main serotonin metabolite, 5-HIAA, were measured along with arginine and glutamine under all conditions. In 12:12 conditions, a circadian rhythm of dopamine, glutamate and GABA was found in both the striatum and nucleus accumbens. Again under 12:12 conditions, DOPAC, HVA, 5-HIAA, and arginine, but not glutamine, fluctuated in a circadian rhythm. In the striatum under constant light conditions, there was a circadian rhythm of dopamine, glutamate, GABA, DOPAC and HVA, but not 5-HIAA. By contrast, when the rats were kept under continuous dark, dopamine and its metabolites, DOPAC and HVA (but not glutamate and GABA), did not fluctuate in a circadian rhythm. In the nucleus accumbens, under both constant light or dark conditions, no changes were found in the circadian rhythm in any of the neurotransmitters and metabolites studied. These findings show that in the striatum, dopamine but not glutamate and GABA, seem to be influenced by light. In the nucleus accumbens, however, the three neurotransmitters had a circadian rhythm, which was independent of light.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2003

Aortic dissection surgery: experience of 78 cases.

From May 1990 to January 2001, 78 patients underwent surgery for aortic dissection, 68 (87%) of type A. Presentation was acute in 55 patients (71%). For type A dissection, in-hospital mortality was 13% (9 patients) and late mortality was 16%. For type B dissection, in-hospital and late mortality were both 30% (3 patients). The follow-up was complete and medical and imaging controls were performed periodically. Computerized axial tomography has shown persistence of distal aortic dissection in 18 patients, one of whom maintained dissection of the supraaortic trunks with false lumen thrombosis. Six patients maintained signs of dissection in the thoracic and abdominal aorta with patent false lumen. In another eight patients the false lumen was thrombosed. In 3 cases the dissection was located in the abdominal aorta. Two patients developed pseudoaneurysms of the thoracic aorta, one of whom was reoperated due to symptoms of dysphagia and chest pain, with angiographic signs of probable rupture of the aorta. Periodic imaging monitoring is essential, as it allows assessment of the extent of residual aortic disease and its evolution, with early detection of possible complications. This will enable prompt and safe action in those patients who may benefit from reoperation.

Adolescent↗