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Biomedical subjects

F Arias

Publications and source records attributed to F Arias.

At least 73 records · Page 4Linked to original sources
PubMed1982

Etiology and outcome of low birth weight and preterm infants.

A population of 489 low birth weight infants was studied to identify specific subgroups with high neonatal morbidity and mortality. It was found that 134 (27.4%) of these infants were born at term but were small for gestational age. The other 355 were preterm and contributed most of the mortality and morbidity of the overall population. There was no significant difference in morbidity and mortality between preterm small and appropriate for gestational age infants. The etiologic analyses show that premature rupture of the fetal membranes and maternal-fetal problems are more frequent causes of low birth weight than preterm labor and that they cause significantly more severe neonatal morbidity. It is concluded that only by developing means to improve the outcome of patients with premature rupture of the membranes and maternal-fetal problems will it be possible to decrease significantly the unacceptably high mortality and morbidity of low birth weight infants.

Cesarean Section↗
PubMed1981

Synthesis and catabolism of progesterone in placentas from normotensive and severely hypertensive patients before and after parturition.

We measured the synthesis of progesterone (P) from pregnenolone and its conversion into 20 alpha-dihydroprogesterone (20 alpha-DHP) in placentas obtained from 12 patients with severe pregnancy-induced hypertension and from 24 normotensive patients. There was no significant difference between placentas from hypertensive and normotensive patients with respect to mitochondrial 3 beta-hydroxysteroid dehydrogenase: delta 5-isomerase activity both before and after labor, indicating that the capacity of this organ to synthesize P remains unchanged during labor in both groups of patients. There was a significant (p less than 0.05) difference in 20 alpha-hydroxysteroid dehydrogenase (20 alpha-HSDH) activity in placental supernatants obtained from normotensive patients before (853.58 +/- 293 pmoles of 20 alpha-DHP/mg of protein/hr) and after (1,156.66 +/- 280 pmoles/mg of protein/hr) labor. In contrast, 20 alpha-HSDH activity in placental supernatants obtained from hypertensive women before (644.30 +/- 236 pmoles/mg of protein/hr) and after (697.17 +/- 524 pmoles/mg of protein/hr) labor was not significantly different. As a consequence, the endogenous 20 alpha-DHP concentration, which was significantly increased after labor in placentas from normotensive women, remained unchanged in placenta from women with pregnancy-induced hypertension. These results indicate that premature activation of the P to 20 alpha-DHP pathway causing "in situ" P withdrawal does not seem to be an adequate explanation for the increased contractility and the tendency to preterm labor commonly exhibited by patients with pregnancy-induced hypertension

20-Hydroxysteroid Dehydrogenases↗
PubMed1980

Maternal pulmonary edema resulting from betamimetic and glucocorticoid therapy.

Four cases are presented of maternal pulmonary edema occurring in patients who had no primary cardiac disease but who were receiving terbutaline and glucocorticoids or terbutaline alone for treatment of premature labor. Fluid overload was the event that triggered this decompensation. The physiologic high-output cardiac state of pregnancy is described and the manner in which betamimetic drugs and corticosteroids exacerbate this situation and cause congestive heart failure is shown. Methods of management to avoid this complication of premature labor therapy are suggested.

Adolescent↗
PubMed1980

Triple heart valve prosthesis and pregnancy.

An unusual case of a successful pregnancy in a patient with aortic, mitral, and tricuspid heart valve prostheses is presented and pertinent management problems are discussed. Although anticoagulation offers protection to the mother from thromboembolic episodes, it carries a high risk for maternal morbidity and fetal wastage.

Adult↗
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↗
PubMed1978

Aortic stenosis and pregnancy.

Pregnancy in patients with aortic stenosis results in a maternal mortality rate of 17.4% and perinatal mortality rate of 31.6%. Medical treatment, valve replacement and termination of pregnancy are the main modes of therapy. The number of cases reported in the literature is small, and the indications for selecting one method of management over the others have not been established. A case is presented that illustrate some of the difficulties encountered in the management of these patients.

Adult↗
PubMed1977

The diagnosis and management of intrauterine growth retardation.

Twenty-eight pregnant patients exhibiting subnormal fetal growth patterns by serial ultrasonic cephalometry were studied. Only 12 (43%) delivered small-for-gestational-age (SGA) infants indicating a poor correlation between the prenatal assessment of intrauterine growth retardation (IUGR) by ultrasonic cephalometry and the neonatal evaluation of the newborn as SGA. The most important factors in the evaluation of the fetus with subnormal serial ultrasonic cephalometry were: 1) the type of ultrasonic growth pattern ("late flattening" vs "low growth profile"), 2) the presence or absence of maternal high-risk factors, and 3) the gestational age of the fetus at the time of detection of the growth abnormality. A pregnancy showing a late flattening type of growth pattern by serial ultrasound in the presence of maternal high-risk factors and with the growth abnormality being detected before 35 weeks of gestation, almost certainly will terminate with the birth of a SGA infant. On the contrary, serial plasma free estriol determinations were not useful in predicting the fetal status at birth. All but 4 of these patients were delivered at term and there was neither perinatal mortality nor significant morbidity. It is suggested that the existence of an abnormal cephalometric pattern is not an indication for early delivery unless fetal distress is detected by means of an oxytocin challenge test.

Cephalometry↗
PubMed1977

Maternal death in a patient with Eisenmenger's syndrome.

A pregnant patient with Eisenmenger's syndrome is reported. The hemodynamic data gathered during this pregnancy suggest that decreased peripheral vascular resistance and reflex bradycardia secondary to postural changes could be of extreme importance in contributing to the extremely high maternal mortality. Suggestions are made with respect to the management of these patients which could be of value in preventing maternal death.

Adult↗
PubMed1976

Hepatic fibrinogen deposits in pre-eclampsia. Immunofluorescent evidence.

To investigate if fibrin (or fibrinogen), immunoglobulins and complement were present in the liver of patients with toxemia of pregnancy, we performed immunofluorescence studies on needle biopsies of pre-eclamptic women. Fibrin (or fibrinogen) outlining the hepatic sinusoids was found in all 12 cases; in two of them there were also large nodular deposits of fibrin (or fibrinogen) and to a lesser extent of IgG, IgM and C3 in areas of necrosis. Immunofluorescence study of 13 control liver biopsies, six from pregnant women, was negative. Our findings suggest that the factors involved in glomerular and hepatic injury are similar. To explain the predominant involvement of liver and kidney, we propose that in these organs, the vasospasm characteristic of toxemia is more severe; this enhanced severity, in the presence of a systemic yet mild blood hypercoagulability, would create adequate local conditions for the precipitation of fibrin-fibrinogen.

Adolescent↗