J.A Molina-Font

Analysis of organochlorine pesticides in human milk: preliminary results

In the face of evidence of human milk contamination by organochlorine pesticides, an analysis was performed on samples of milk obtained from healthy lactating women in the provinces of Granada and Almeria in Southern Spain. The samples were obtained by the Neonate Section of the Department of Pediatrics of Granada University Hospital (Neonatology Division) and by the Neonatal Service of Poniente Hospital in El Ejido, Almería. A liquid-liquid extraction procedure was performed. The cleaning of the sample before gas chromatography-mass spectrometry (GC-MS) used silica Sep-Pak. Among other pesticides, aldrin, dieldrin, DDT and its metabolites, lindane, methoxychlor and endosulfan were identified. The presence of these products was confirmed by mass spectrometry. The identification and quantification of these organochlorine molecules is important because they have estrogenic effects.

Melatonin's role as an anticonvulsant and neuronal protector: Experimental and clinical evidence

The pineal gland classically has been considered as a vestigial and mystic organ. In the last decades, and with the incorporation of new methodologic procedures, it could be proved that it also has physiologic actions that vary depending on the level of the phylogenetic scale. Its best-known secretion, melatonin, has been related to many different actions, such as sleep promotion, control of biologic rhythms, hormonal inhibition, and an inhibiting action on central nervous system regulation mechanisms. In animal experimentation, there are papers even accepting an anticonvulsant effect. In humans, evidence is reduced to few experiences. In addition to this clinical experience, there is other evidence that clearly relates melatonin to convulsive phenomena. This relationship must be mediated by the following mechanisms attributed to melatonin: altered brain GABAergic neurotransmission, its known interaction with benzodiazepinic brain receptors, through tryptophan metabolite activity (kynurenine, kynurenic acid), or even by its efficacy as a free-radical scavenger. (J Child Neurol 1998;13:501-509).

Prenatal care and prevention of preterm birth

The value of prenatal care is controversial and difficult to establish. A national policy for improving perinatal outcomes was proposed and applied throughout Andalusia (Southern Spain) in 1984. Here we report the results of an evaluation of this health care program as regards the prevention of preterm delivery. Effectiveness of prenatal care was assessed on the basis of two case-control studies in a hospital setting: one performed before the program was implemented (1981–1982) and the second one six years after the program began (1990–1993). A total of 229 cases and 395 controls for the period 1981–1982, and 207 cases and 381 controls for 1990–1993 were selected. Prenatal care was assessed based on the number of prenatal care visits, the date of the first visit, and an American composite index adjusting for gestational age. Multiple-factor adjusted odds ratios and their 95% confidence intervals (CI) were estimated using unconditional logistic regression analysis. The use of prenatal care significantly improved across time: the proportion of women receiving no prenatal care decreased from over 30% to less than 5%, and the proportion of women starting prenatal care in the first trimester for 1990–1993 was three times greater than the figure for 1981–1982. In the 1981–1982 case-control study, the date of first visit and the composite index were shown to be unrelated to preterm birth risk; and the number of visits yielded a significant association, although no definite trend could be established. In the 1990–1993 case-control study, a clear and significant relationship was observed between the number of prenatal care visits, the trimester of the first visit, and the adequacy of care according to the composite index. This latter variable, reflecting a more stringent standard of prenatal care, was selected by a stepwise logistic regression analysis as the best predictor for preterm birth risk. The results suggest that the present Andalusian program helps prevent preterm delivery. Nonetheless, its minimum standards should be raised to further decrease preterm birth risk.

Nutrition and fetal growth

Essential factors for normal fetal growth include the correct utilization by the fetus of a suitable supply of energy and plastic nutrients, together with the adequate genic expression of the factors promoting tissue growth and an optimal hormonal framework. The nutritional state and welfare of the mother, the endocrine changes experienced and the uteroplacental function have all been related to the health of the fetus and the newborn infant, premature births, fetal nutritional disorders, certain diseases and even death.

Influence of fish oil or folate supplementation on the time course of plasma redox markers during pregnancy

Maternal supplementation with long-chain PUFA, to improve infant neurological development, might cause additional increase of oxidative stress. Pregnant women aged 18-41 years were randomised into one of four supplementation groups. From week 22 on, they received supplements containing either modified fish oil (n 69), 5-methyl-tetrahydro-folate (n 65), both (n 64), or placebo (n 72). Plasma Trolox-equivalent antioxidative capacity (TEAC), concentrations of alpha-tocopherol, retinol, beta-carotene, free thiol groups, uric acid and thiobarbituric acid-reactive substances (TBARS) were determined at weeks 20 and 30 and at delivery. The studied antioxidants showed no significant differences between the four supplementation groups. At week 30 plasma TBARS levels were found to be significantly higher in the fish oil group (0.80 (sem 0.04) micromol/l) than in the folate (0.67 (sem 0.03) micromol/l; P = 0.024) and control (0.69 (sem 0.04) micromol/l; P = 0.01) groups. Concentrations of retinol and free thiol groups decreased during pregnancy, whereas uric acid increased and beta-carotene as well as TEAC showed only minor changes. Fish oil supplementation during the second half of pregnancy appears not to decrease antioxidant status. The increased TBARS levels at week 30 may indicate a period of increased oxidative stress in plasma at this time.