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Biomedical subjects

F Arias

Publications and source records attributed to F Arias.

At least 55 records · Page 3Linked to original sources
PubMed1993

Analysis of factors determining the selection of repeated cesarean section or trial of labor in patients with histories of prior cesarean delivery.

We investigated the motivation behind procedures in 241 patients with prior cesarean births; 120 had elective repeat cesarean sections and 121 had vaginal birth after cesarean section (VBAC). Patients were of similar age, gravity and parity, but significantly more patients in the repeat cesarean group had their initial surgery because of failure to progress in labor; significantly more patients in the VBAC group had their initial cesarean section because of fetal distress. The main factors behind the decision to attempt VBAC were patient's desire (81.0%), patient's desire and physician's advice (12.4%) and physician's advice (6.6%). The main factors behind the decision to have repeat cesarean sections were medical or obstetric indication (45.8%), patient's desire (31.6%), patient's desire and physician's advice (9.1%) and physician's advice (13.3%). We conclude that it will be difficult to substantially decrease the present rate of repeat cesarean births, and that preventive efforts should be directed toward decreasing the incidence of primary cesarean deliveries.

Adult↗
PubMed1992

[Arterial hypertension in the adolescent: its possible relation to the salt taste threshold].

The purpose of the study was to define the relationship between the salt intake and the levels of arterial blood pressure in adolescent people. Seventy-eight youngs between 12 and 18 years old with diastolic/systolic blood pressure above 95 percentile formed the hypertensive group; a similar population with the same characteristic (age, sex, race, weight and height) with normal blood pressure were selected as a control group. The salt taste threshold was carried out through tasting a saline solution in different concentrations, till it could be distinguished as salted. Moreover, 45 hypertensive adolescent were follow-up for 12 weeks under a hiposodic diet and consequently a new salt taste threshold was done. The results showed that the control group had a salt perception under 80 mg %, instead the hypertensive group showed a higher threshold (above 160 mg %). Those hypertensive adolescent which were followed for 12 weeks changed its pattern in this way: in 24, a lesser perception was observed with a reduction in their blood pressure in 11 of them. These findings suggest that hypertensive adolescent had an elevated threshold for salt, usually above 160 mg % and the test should be helpful for the identification of a subgroup "salt-sensible".

Adolescent↗
PubMed1988

The use of Doppler waveform analysis in the evaluation of the high-risk fetus.

The development of Doppler ultrasound evaluation of the uteroplacental and fetoplacental circulations is one of the most important achievements of modern obstetrics. For the first time, the obstetrician has the ability to evaluate, in a noninvasive way, circulatory systems critical to fetal development and the outcome of pregnancy and to obtain information of great value for the management of complicated pregnancies. At this time, Doppler examination of the umbilical artery has become a fundamental part of the evaluation of pregnancies complicated by retarded fetal growth. Doppler examination of the umbilical and uterine arteries has become the most accurate test to establish a fetal prognosis in patients with hypertension in pregnancy. Other indications for the use of this methodology (twins, diabetes, Rh isoimmunization, etc.) are being studied, and the role of Doppler ultrasound probably will extend significantly beyond the now well-established indications for its use.

Blood Flow Velocity↗
PubMed1988

Cervical cerclage for the temporary treatment of patients with placenta previa.

Cervical cerclage as a temporizing measure for the treatment of patients with placenta previa was evaluated in 25 patients admitted to the hospital for vaginal bleeding between 24-30 weeks' gestation and sonographic evidence of a placenta previa. The patients were randomly assigned to either cerclage (13) or conventional management (12). Cerclage patients had significantly better perinatal outcome, as indicated by more advanced gestational age at the time of delivery (34.9 +/- 3.0 versus 31.6 +/- 2.9 weeks; P = .02), larger birth weight (2709 +/- 511 versus 1812 +/- 506 g; P = .002), and fewer neonatal complications (two of 13 versus ten of 12 infants; P = .001). Maternal bleeding was more frequent and severe for patients in the control group. The total hospital cost was less for cerclage patients than for those receiving conventional expectant management ($9898 +/- 3943 versus $27,271 +/- 9901; P = .02). These results support the use of cervical cerclage for the treatment of patients with symptomatic placenta previa early in gestation.

Blood Transfusion↗
PubMed1987

Predictability of complications associated with prolongation of pregnancy.

The frequency of complications and fetal macrosomia occurring in 243 patients with excellent dates indicating that their pregnancy was prolonged beyond 40 weeks (280 days) was analyzed and compared with that from a control group of 250 normal patients whose pregnancy ended spontaneously between 38 and 40 weeks of gestation. Complications (intrapartum fetal distress, traumatic deliveries, meconium aspiration, postmaturity syndrome) were significantly more frequent in patients in the study group (25.1%) than in the controls (5.6%). Similarly, fetal macrosomia occurred significantly more often in the study patients (29.6%) than in the controls (10.4%). To study the efficacy of antepartum surveillance in predicting these abnormal events, the postterm patients were randomized between two plans of management: 126 were followed with weekly nonstress testing (NST), and 117 with NST plus weekly ultrasound evaluation of fetal size, amniotic fluid volume, and placental grade. Contraction stress testing (CST) was used if the NST was nonreactive. Electronic monitoring had positive and negative predictive values of 42.8 and 87.7%, respectively, whereas ultrasound-plus-electronic monitoring had values of 50 and 65.3%, respectively. These results indicate that the increased incidence of complications in pregnancy prolonged beyond 40 weeks cannot be adequately predicted with antepartum electronic monitoring and ultrasound evaluation of fetal size, placental grade, and amniotic fluid volume.

Adult↗
PubMed1986

A retrospective study on the effects of steroid administration and prolongation of the latent phase in patients with preterm premature rupture of the membranes.

To address the issues of whether corticosteroid treatment and prolongation of the latent phase improve the outcome of pregnancy in patients with preterm premature rupture of the membranes, we studied 96 patients with premature rupture of the membranes who were delivered of infants of adequate weight for gestational age with birth weights between 751 and 2000 gm and who had a latent period longer than 48 hours. Of these 96 infants, 53 received treatment with steroids and tocolytic agents and 43 received no treatment. We found a significant decrease in perinatal mortality and in the incidence of moderate and severe hyaline membrane disease in infants whose mothers received glucocorticoids. The protective effect of glucocorticoid therapy was limited to infants with a birth weight between 751 and 1000 gm or with a gestational age of 27 to 28 weeks. We also found a significant increase in perinatal mortality, mainly due to infection, when the latent phase was prolonged for greater than 7 days, regardless of the type of management.

Betamethasone↗
PubMed1985

Biochemical and morphologic effects of ethanol on fetuses from normally ovulating and superovulated mice.

To further our understanding about the teratogenicity of ethanol, we studied the changes produced by this compound in the incorporation of glucose 14C into several tissue fractions of 12-day mice fetuses and the morphologic alterations present at day 19 of gestation. Furthermore, to determine if the fetal toxicity of ethanol was modified by changes in the characteristics of the pregnancy, we performed similar biochemical and morphologic observations in fetuses from superovulated mice. Maternal ethanol administration caused biochemical alterations in the fetal tissues of both normally ovulating and superovulated mice, but it caused morphologic alterations predominantly in fetuses from superovulated animals. The prevalent morphologic alteration found in ethanol-treated animals was a hemorrhagic lesion dorsal to the lumbar or dorsal vertebrae. These results suggest that superovulation increases the susceptibility of the fetal mice tissues to the teratogenic effects of ethanol.

Abnormalities, Drug-Induced↗
PubMed1984

Effects of ethanol on alcohol dehydrogenase and microsomal ethanol oxidative system activities in fetal mice.

In an attempt to better understand the mechanism of the fetal damage caused by ethanol, we studied the effects of its administration on the activity of some ethanol metabolizing enzymes in mice fetuses. Animals were given a single ethanol injection (0.01 ml of a 25% solution in 0.9% sodium chloride per gram of body weight) on day 12 of pregnancy and were divided into groups that were killed 24, 48, and 72 hours later. The fetal and maternal livers were isolated, homogenized, and divided into subcellular fractions. Alcohol dehydrogenase, NADH-cytochrome C reductase, NADPH-cytochrome C reductase, and cytochrome P-450 activities were measured and compared with those of control animals injected with saline solution. We found that ethanol caused (1) a significant but transient increase in fetal alcohol dehydrogenase activity, (2) a significant and persistent increase in fetal cytochrome P-450 and NADPH-cytochrome C reductase activities, and (3) no change in fetal NADH-cytochrome C reductase activity. These effects were similar although quantitatively smaller than those observed in the maternal liver and disappeared after pretreatment with metyrapone. This work demonstrates that ethanol has a similar effect upon both maternal and fetal ethanol metabolizing enzymes and gives experimental support to the possibility that a reactive product of the interaction between ethanol and the cytochrome P-450 system may be responsible for the embryotoxic effects of this compound.

Alcohol Oxidoreductases↗
PubMed1983

Use of trophoblast cells in tissue culture for fetal chromosomal studies.

The objectives of this research were to determine optimal conditions for culturing trophoblast cells in vitro and to ascertain whether cells maintained under these conditions are an adequate source of material for fetal chromosome studies. Best results were obtained with the use of 1.25 X 10(6) cells in a total volume of 4 ml of M-199 medium that contained 20% calf serum and 1 mg/ml glucose, incubated in an atmosphere of 95% air and 5% carbon dioxide. Cytogenetic analysis was performed in trophoblast cultures 14 to 64 days old. In all cases it was possible to identify cells in metaphase which were adequate for karotyping. Evidence that the cultured cells were fetal in origin was provided by two cases in which chromosome abnormalities--46,XY,inv(18), and 47,XX, + 21--were identified both in the placental cultures and in leukocytes and fibroblasts from the fetus. The cytogenetic analysis was correct in the prediction of the fetal sex in seven cases; in two cases the prediction was questionable, and in two cases it was in error. The conclusion is that the use of trophoblast cells for fetal cytogenetic studies is not practical because of (1) difficulties in culturing the cells, (2) the low mitotic frequency of the cells in culture, and (3) contamination of the culture with maternal fibroblasts.

Cells, Cultured↗
PubMed1982

Plasminogen activator production by trophoblast cells in vitro: effect of steroid hormones and protein synthesis inhibitors.

Variations in the production of plasminogen activator (PA), a proteolytic enzyme that has been associated with trophoblast invasiveness, may be critical to the success or failure of placentation. To understand better the mechanisms regulating PA production we have cultured human trophoblast cells and measured the effect of steroid hormones and protein synthesis inhibitors upon their capacity to lyse 125I-fibrinogen. Progesterone (P) and 17 beta-estradiol (E2) at concentrations of 10(-8)M, 10(-7)M, and 10(-5)M did not cause significant changes in PA or chorionic gonadotropin (hCG) production by the trophoblast cells. In contrast, dexamethasone (10(-8)M and 10(-5)M) caused a significant, dose-dependent decrease in PA production. There was no significant difference in PA and hCG production between trophoblast cultures treated with cytosine arabinoside (1 mg/ml) and untreated cultures. When actinomycin D (0.5 microgram/ml) was added to cultures at time zero, the production of PA and hCG during the first 24 hours of incubation was not significantly different from that of untreated cultures. After 24 hours, however, PA and hCG disappeared from the actinomycin-treated cultures while both substances continued to be released in the untreated controls. These experiments indicate that trophoblastic PA and hCG production in vitro are independent of DNA replication and not under P or E2 control. They also show that PA and hCG are stored within the trophoblast cells and released into the medium during the first 24 hours of incubation; after this period the presence of PA and hCG in the medium represents de novo synthesis. The data also suggest that, similar to hCG, PA is produced continuously in vitro as long as the trophoblast cell is functionally active.

Animals↗