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Biomedical subjects

F Arias

Publications and source records attributed to F Arias.

At least 19 recordsLinked to original sources
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↗
PubMed1979

Metabolism of progesterone by placentas from several mammalian species in vitro.

20-alpha-Hydroxysteroid oxidoreductase (20-alpha-HSDH) activity and 20-alpha-dihydroprogesterone concentration (20-alpha-DHP) reach peak values in the human placenta after vaginal delivery. To determine if these findings are unique to the human, we measured 20-alpha-HSDH activity as well as endogenous progesterone (P) and 20-alpha-DHP concentration in the soluble supernatant fraction of placental tissues obtained from rodents (rat, rabbit, guinea pig), ungulates (horse, zebra, giraffe, cow), and primates (squirrel monkey, orangutan, man). P concentration was very low in rodents (mean 0.60 ng/mg protein), increased slightly in ungulates (mean 2.89 ng/mg protein), and reached a maximum value in the human (34.43 ng/mg protein). 20-alpha-DHP concentration had a strong positive correlation (r = 0.93) with P tissue content; it was low in rodents (mean 0.21 ng/mg protein), increased slightly in ungulates (mean 0.79 ng/mg protein), and reached a maximum value in the human (39.53 ng/mg protein). 20-alpha-HSDH activity, however, had a poor correlation with 20-alpha-DHP tissue concentrations: Its lowest value was in the guinea pig (9.34 pmole/mg protein/hour) and the highest was in the horse (3.19 nmole/mg protein/hour). These results indicate that a high level of activity of the P to 20-alpha-DHP pathway with significant tissue accumulation of 20-alpha-DHP is unique to the human placenta and reinforce the possibility of its causing in situ P withdrawal as a part of the overall mechanism of human parturition.

20-alpha-Dihydroprogesterone↗
PubMed1979

Changes in human amniotic fluid lecithin/sphingomyelin ratio and dipalmitoyl lecithin associated with maternal betamethasone therapy.

In an effort to understand the biochemical changes responsible for the decreased incidence of neonatal RDS observed in premature infants delivered after maternal glucocorticoid therapy we have compared quantitative changes in L/S ratio and qualitative changes in dipalmitoyl lecithin in serial amniotic fluid samples from 20 pregnant women treated with betamethasone and 11 patients who had repeated amniocentesis at similar gestational age but did not receive glucocorticoids. Initial L/S ratio values were not significantly different between treated (1.24 +/- 0.24 [S.D.]) and control (1.09 +/- 0.29 [S.D.]) groups but the values obtained within 1 week after therapy (1.49 +/- 0.21 [S.D.]) were significantly higher (t=3.8; p less than 0.01) than those obtained after a similar period in the untreated group (1.24+/- 0.29 [S.D.]). However, only one of the treated patients reached a mature L/S ratio (2.0 or more). Simultaneously, 10 of 17 treated patients exhibited increases in the amount of dipalmitoyl lecithin within the first week after treatment, wheras no change was detected in serial samples from six control patients (p = 0.016). These results indicate that qualitative changes in amniotic fluid lecithin composition are a part of the fetal response to glucocorticoids which may be responsible for the decreased incidence of RDS observed after treatment.

Amniocentesis↗
PubMed1979

Whole-blood fibrinolytic activity in normal and hypertensive pregnancies and its relation to the placental concentration of urokinase inhibitor.

Whole-blood fibrinolytic activity was measured in 68 pregnant and 29 nonpregnant women with a sensitive, solid-state assay in which 125I-labeled fibrin was bound to polystyrene tubes. Antepartum fibrinolytic activity in 36 normotensive gravid women [234.5 +/- 29.2 (mean +/- standard error of the mean) ng fibrin lysed/30 min] was significantly (p less than 0.001) greater than that found in 28 nonpregnant normotensive women not taking oral contraceptives (63.61 +/- 7.66 ng fibrin lysed/30 min) and not different from the activity observed during the active phase of labor (198.50 +/- 16.5 ng fibrin lysed/30 min.) Normotensive pregnant patients had a significant (p less than 0.001) increase in whole-blood fibrinolytic activity (341.04 +/- 25.7 ng fibrin lysed/30 min) within the first 24 hours after delivery which persisted in measurements taken the second postpartum day. Fibrinolytic activity values before labor, in the active phase of labor, and in the first and second postpartum days in 17 patients with mild to moderate pregnancy-induced or pregd or pregnancy-aggravated hypertension were not different from those found in the normotensive group. However, patients with severe pregnancy-induced or pregnancy-aggravated hypertension had significantly (p less than 0.01) lower levels of fibrinolytic activity than normotensive patients before labor, during the active phase of labor, and on the first and second postpartum days. The placental 800 X g and 110,000 X g fractions of patients with severe hypertension had a significantly (p less than 0.001) greater capacity to inhibit "in vitro" urokinase-induced fibrinolysis than similar fractions obtained from placentas of normotensive women, and there was a significant inverse correlation (r = 0.61; p less than 0.01) between whole-blood fibrinolytic activity and urokinase inhibition by placental fractions. Our findings indicate that contrary to widely held views, fibrinolysis is extremely active in term pregnancies and during labor and that a derangement of this activity is present in cases of severe pregnancy-induced or pregnancy-aggravated hypertension.

Adolescent↗
PubMed1979

20 alpha-Hydroxysteroid oxidoreductase activity and 20 alpha-dihydroprogesterone concentration in human placenta before and after parturition.

The objective of this investigation was to determine if decreased biosynthesis or increased catabolism of progesterone (P) during labor was responsible for the decreased concentration of hormone observed in the human placenta after labor and vaginal delivery. No significant difference was found in P biosynthesis by placental tissues examined before and after labor as evidenced by a similar activity of 3 beta-hydroxysteroid dehydrogenase: delta 5-isomerase. In contrast, there was a marked increase in P catabolism during labor, as shown by a significant (p less than 0.05) change in placental 20 alpha-hydroxysteroid oxidoreductase activity which increased from 835.5 +/- 103 (mean +/- SEM) pmoles of 20 alpha-dihydroprogesterone (20 alpha-DHP) generated per milligram of protein per hour before labor to 1,160.4 +/- 101 pmoles/mg/hr after labor. A similar significant (p less than 0.02) increase in enzyme activity was noticed in parallel assays of the reverse (20 alpha-DHP leads to P) reaction. As a consequence of increased P catabolism, placentas after labor had a 20 alpha-DHP concentration of 63.7 +/- 9.5 (mean +/- SEM) ng/mg protein, a value which was significantly (p less than 0.05) larger than that found before labor (37.8 +/- 8.3 ng/mg protein). These changes resulted in a modification of the placental tissue P/20 alpha-DHP ratio which decreased from 2/1 before to 1/1 after labor. The results indicate that the catabolism of P to 20 alpha-DHP increases significantly during human parturition. This phenomenon may be of importance in the mechanism of initiation and continuation of labor.

20-Hydroxysteroid Dehydrogenases↗
PubMed1978

Studies with a pancreatic beta cell simulator in the third trimester of pregnancies complicated by diabetes.

To determine the potential of an artificial pancreatic beta cell simulator as a therapeutic and research tool we have used the device for short-term monitoring and control of blood glucose concentrations in five pregnant patients with juvenile-onset diabetes (White's Class C) and three pregnant patients with maturity-onset diabetes (Class B). One patient with brittle juvenile-onset diabetes had successful control before, during, and after cesarean section. The other seven patients were studied during the third trimester of pregnancy and at least four weeks before delivery. Blood glucose control with Biostator regulation was excellent (mean, 96 mg. per deciliter; range, 85 to 107). The insulin requirements needed to achieve optimal glucose control with the Biostator were highly variable (range, 20 to 157 U. per 24 hours) but very similar to those previously calculated to provide optimal control by conventional means. Insulin requirements were unrelated to plasma growth hormone, placental lactogen, or glucagon concentrations. The greatest degree of insulin resistance was seen in obese patients with endogenous insulin-secretory capacity. This study indicates that a pancreatic beta cell simulator can normalize glucose concentrations and rapidly estimate daily insulin requirements in pregnant diabetic patients. In addition, the data suggest that exogenous insulin may indirectly suppress endogenous insulin secretion and thus contribute to the "insulin resistance" of obese patients with maturity-onset diabetes.

Adult↗
PubMed1978

Intrauterine resuscitation with terbutaline: a method for the management of acute intrapartum fetal distress.

Terbutaline, a selective beta-2 adrenergic receptor stimulator, has been used to decrease myometrial activity and improve uteroplacental blood flow in 15 patients with acute intrapartum fetal distress. In all cases electronic monitoring gave evidence of partial or total fetal recovery after therapy. Thirteen of these patients were delivered by cesarean section and two were allowed to resume labor and deliver vaginally. In 10 cases the initial Apgar score was 7 or more and in all cases the score was 7 or more after 5 minutes of life. No significant maternal morbidity occurred as a consequence of the treatment. These results suggest that inhibition of uterine activity with terbutaline may be a valuable maneuver in the management of patients with severe intrapartum fetal distress.

Acute Disease↗
PubMed1978

Correlation between amniotic fluid optical density, L/S ratio, and fetal pulmonary maturity.

The correlation between lecithin/sphyngomyelin ratio (L/S ratio) and amniotic fluid optical density at 400 (OD400) and 650 (OD650) nm was studied with 102 samples of fluid obtained from 72 patients. The accuracy of each method in predicting the respiratory outcome of the newborn was also evaluated in 28 patients who delivered within 48 hours after amniocentesis. Results indicate that the correlation between spectrophotometric analysis and L/S ratio is poor and that the latter is a better predictor of neonatal respiratory outcome. It is concluded that measurements of amniotic fluid optical density are not an acceptable substitute for the L/S ratio in evaluating fetal pulmonary maturity.

Amniotic Fluid↗