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Biomedical subjects

J A Miranda

Publications and source records attributed to J A Miranda.

At least 19 recordsLinked to original sources
PubMed2004

Intrapartum fetal pulse oximetry and fetal heart rate decelerations.

OBJECTIVES: To determine the behavior of fetal oxygenation (FSpO(2)) in different patterns of fetal heart rate decelerations (FHR). METHODS: A total of 787 decelerations were studied. RESULTS: FSpO(2) decreased significantly during decelerations, especially when the alteration was prolonged. CONCLUSIONS: Modifications in FHR occur simultaneously with alterations in FSpO(2), although the latter do not persist in time. Different degrees of FSpO(2) seen prior to deceleration are an expression of fetal respiratory status.

Adolescent↗
PubMed2002

Prospective, randomised study with three HRT regimens in postmenopausal women with an intact uterus.

OBJECTIVE: To compare compliance, symptom control, bleeding patterns, lipid and biochemical changes in postmenopausal women treated with three regimens of HRT. METHODS: In a prospective, randomised, group comparative study, with 165 patients, the effects on the aforementioned parameters, as well as treatment compliance and side effects were studied with oral tibolone 2.5 mg per day, with cyclic combined regimen of transdermal oestrogen and progestogen (transdermal patch of 17beta-oestradiol 50 microg/day during 14 days and transdermal patch of 17beta-oestradiol 50 microg/day plus 0.25 mg/day NETA during the following 14 days), and with intermittent progesterone regimen (transdermal 17beta-oestradiol 50 microg/day and oral micronised natural progesterone 200 mg twice a week). Statistical analysis was carried out using the Fisher-test, analysis of the variance (ANOVA) and the Bouferoni test. RESULTS: Ten women dropped out of the tibolone group, 11 dropped out of the intermittent dosing group and 21 dropped out of the cyclid combined group. Irregular bleeding occurred at more rates in the cyclid combined group. Similar reductions in climacteric symptoms were found in the three groups. No differences were observed with respect to biochemical analysis. CONCLUSIONS: Efficacy and safety of the three treatment regimens being comparable, but the patients in our study preferred those that did not produce bleeding episodes.

Administration, Cutaneous↗
PubMed2001

Saffman-Taylor problem on a sphere.

The Saffman-Taylor problem addresses the morphological instability of an interface separating two immiscible, viscous fluids when they move in a narrow gap between two flat parallel plates (Hele-Shaw cell). In this work, we extend the classic Saffman-Taylor situation, by considering the flow between two curved, closely spaced, concentric spheres (spherical Hele-Shaw cell). We derive the mode-coupling differential equation for the interface perturbation amplitudes and study both linear and nonlinear flow regimes. The effect of the spherical cell (positive) spatial curvature on the shape of the interfacial patterns is investigated. We show that stability properties of the fluid-fluid interface are sensitive to the curvature of the surface. In particular, it is found that positive spatial curvature inhibits finger tip-splitting. Hele-Shaw flow on weakly negative, curved surfaces is briefly discussed.

Journal Article↗
PubMed2001

Changes in the rate of tubal ligation done after cesarean section.

OBJECTIVE: We studied tubal ligations done after cesarean section in a Spanish hospital during a 20-year period, in order to analyze changes in patient characteristics and indications for cesarean delivery. STUDY DESIGN: We reviewed the clinical records, for the period from 1978 to 1997, of 1996 cases of cesarean section followed by tubal ligation in 108776 births in which the fetus weighed 1000 g or more. RESULTS: During the 20-year period of study, the proportion of cesarean sections relative to vaginal deliveries increased, as did the frequency of cesarean section followed by tubal ligation relative to cesarean and vaginal deliveries. The proportion of women who underwent tubal ligation after a second cesarean section decreased from 60% during 1978-1982 to 5.6% during 1993-1997. The most frequent maternal pathology associated with gestation was previous cesarean section (60.5%), although 50% of the women had no underlying pathology. CONCLUSIONS: In our setting, the rate of cesarean section followed by tubal ligation has been increasing steadily since the early 1980s. The proportion of women who requested tubal sterilization and who had only one living child, or who had had a previous cesarean birth, also increased.

Adolescent↗
PubMed2001

Meconium-stained amniotic fluid in labor: a randomized trial of prophylactic amniofusion.

OBJECTIVES: To investigate the effect of amnioinfusion in women with meconium-stained amniotic fluid on the rate of cesarian sections and on neonatal morbidity. STUDY DESIGN: A randomized controlled trial. A total of 206 women with meconium-stained amniotic fluid were assigned to receive amnioinfusion via two-way catheter or no amnioinfusion (control group). The catheter was inserted and other treatment was the same in both groups. RESULTS: Amnioinfusion decreased the rate of cesarian sections for fetal distress (RR 0.23, 95% CI 0.07-0.79) and increased mean pH at birth (7.24+/-0.1 versus 7.21+/-0.1, P<0.05). It also decreased the frequency of variable fetal heart rate decelerations (RR 0.74, 95% CI 0.59-0.92), and of meconium below the vocal cords in neonates (RR 0.37, 95% CI 0.19-0.69). CONCLUSIONS: Amnioinfusion improves the neonatal outcome and reduces the frequency of cesarian sections.

Adult↗
PubMed2001

Estrogen and xenoestrogens upregulate the brain aromatase isoform (P450aromB) and perturb markers of early development in zebrafish (Danio rerio).

Estrogen synthesized in the brain itself by the action of cytochrome P450 aromatase (P450arom) is known to have permanent organizing effects on the developing CNS. In fish, estrogen upregulates the predominant brain isoform (P450aromB), implying that xenoestrogens (XE) could act as neurodevelopmental toxicants by altering P450aromB. To test this hypothesis, zebrafish embryos were exposed to 17beta-estradiol (E(2)), diethylstilbestrol (DES, a potent agonist), and bisphenol A (BPA, a weak agonist). RT-PCR/Southern transfer analysis showed that E(2) (0.01-10 microM) upregulated P450aromB in a dose-response manner. The effect of DES (0.01 microM) was similar to 1 microM E(2) (three- to four-fold higher than control), but BPA was less effective (<threefold increase at 10 microM). mRNA levels of the predominant ovarian isoform (P450aromA) were unchanged by estrogen. Treatment with E(2) (0.1-10 microM) between 2 and 72 hpf had dose-response effects on mortality and hatching and induced a 'curved tail down' phenotype characteristic of mutants with defects of early CNS development. The critical period of estrogen sensitivity for effects on mortality and curved tails was 2-24 hpf, whereas hatching effects were both stage- and duration-dependent. Developmental effects of DES and BPA were similar to E(2) but testosterone, and 5alpha-dihydrotestosterone were ineffective. 17alpha-Estradiol showed a small but significant effect on curved tails. We conclude that P450aromB mRNA is a sensitive marker of XE effect during embryogenesis, but further studies are required to determine whether changes in neural aromatase expression and estrogen biosynthesis have consequences for CNS development.

Animals↗
PubMed2001

Chronic Trypanosoma cruzi infection associated with low incidence of 1,2-dimethylhydrazine-induced colon cancer in rats.

Experimental data have demonstrated that chronic infection with intracellular parasites may enhance resistance against some types of tumour. This phenomenon has not yet been demonstrated for experimental Trypanosoma cruzi chronic infection. This study investigated the effect of a specific colon cancer inducing drug, 1,2-dimethylhydrazine (DMH), on chronically T.cruzi infected Wistar rats. Infection was obtained by inoculation of 10(5) tripomastigote forms by subcutaneous (s.c.) route. Acute phase of the infection was monitored every other day by examination of a blood smear from each animal until negativation. In the early chronic phase of the infection, colon adenocarcinoma was induced by weekly s.c. injections of DMH at a dose of 20 mg/kg body weight for 12 weeks. 102 animals were divided in four test groups: 39 infected rats received DMH (group 1); 32 non-infected rats received DMH (group 2); 16 infected rats and 15 non-infected animals were used as control groups. Animals were killed 6 months after the first dose of DMH. The whole colon was removed and prepared for light microscopic examination. Twelve animals from group 1 and 22 from group 2 had colon adenocarcinomas, the proportion of cancer being 30.7 and 68.7%, respectively (chi(2) = 10.16; P < 0.05). The relative risk of having a colon tumor in infected animals (group 1) was 0.45 (IC 95% 0.26-0.76), which is a protective risk compared with non-infected animals. These findings show that chronic infection with T.cruzi is associated with a lower incidence of DMH-induced colon cancer in rats.

1,2-Dimethylhydrazine↗
PubMed2000

Gravity-driven instability in a spherical Hele-Shaw cell.

A pair of concentric spheres separated by a small gap form a spherical Hele-Shaw cell. In this cell an interfacial instability arises when two immiscible fluids flow. We derive the equation of motion for the interface perturbation amplitudes, including both pressure and gravity drivings, using a mode coupling approach. Linear stability analysis shows that mode growth rates depend upon interface perimeter and gravitational force. Mode coupling analysis reveals the formation of fingering structures presenting a tendency toward finger tip-sharpening.

Journal Article↗
PubMed1999

Amnioinfusion in term labor with low amniotic fluid due to rupture of membranes: a new indication.

OBJECTIVE: The null hypothesis was that the use of intrapartum amnioinfusion to induce term labor because of premature rupture of membranes when labor was complicated by low amniotic fluid volume due to vaginal loss would not improve fetal heart rate patterns, decrease the incidence of operative delivery, or improve neonatal acid-base status. STUDY DESIGN: 200 term pregnancies with low amniotic fluid due to vaginal loss were randomly chosen to receive intrapartum amnioinfusion or standard obstetric care without amnioinfusion. Fetal heart rate pattern, method of delivery and neonatal acid-base status were compared with Student's t test, chi-squared analysis, Mann-Whitney U- or Fisher's exact test. RESULTS: When amnioinfusion was used, the fetuses had lower rates of variable (74 vs. 91%, P<0.01) or late (26 vs. 58%, P<0.001) decelerations. Spontaneous deliveries were more frequent (77 vs. 59%, P<0.01) and cesarean sections less frequent (3 vs. 10%, P<0.05). Mean umbilical arterial (7.24+/-0.07 vs. 7.21+/-0.08, P<0.01) and venous (7.31+/-0.06 vs. 7.28+/-0.08, P<0.01) pH were significantly higher in newborns with amnioinfusion, and babies in this group had lower rates of neonatal acidemia of arterial (22 vs. 36%, P<0.005) or venous (13 vs. 26%, P<0.005) origin. CONCLUSIONS: Amnioinfusion improved fetal heart rate pattern, lowered the incidence of operative delivery, and improved neonatal acid-base status in term labor complicated by low amniotic fluid due to vaginal loss.

Adult↗
PubMed1998

Amnioinfusion in labor induction of term pregnancies with premature rupture of the membranes and low amniotic fluid.

OBJECTIVE: To analyze the utility of prophylactic amnioinfusion in term pregnancies with PROM and a low amniotic fluid index during labor induction. METHOD: Forty-two women with amnioinfusion and 42 in a control group with amniotic fluid index (AFI) below 10 cm when admitted to labor induction were studied. All patients had electronic fetal heart rate and intrauterine pressure continuous monitoring. Amnioinfusion of normal saline (37 degrees C) was realized in the study group, using a continuous perfusion pump at 600 ml/h for 1 h, after which the AFI was again recorded; if this was < 15, the perfusion was continued at 180 ml/h until full cervical dilatation was achieved or until uterine baseline activity reached 20 mm Hg. The control group received identical obstetric care except in respect of amnioinfusion. RESULT: Both groups were similar in age, primiparity, gestational age, initial AFI, interval from rupture of membranes until delivery and length of labor. The amnioinfusion of 600 ml in 1 h significantly increased the AFI (an increase of 7.2 +/- 3.9 vs. a decrease of 1.1 +/- 1.6, P < 0.01). In the amnioinfusion group, there was a significantly lower rate of cesarean deliveries (0 vs. 6, P < 0.05) and a better mean umbilical arterial pH at delivery (7.24 +/- 0.07 vs. 7.21 +/- 0.08, P < 0.05). No differences were observed in maternal or neonatal hospitalization days or infectious morbidity. CONCLUSION: It is concluded that prophylactic amnioinfusion improves neonatal metabolic state when used in labor induction of term pregnancies with PROM and a low amniotic fluid index.

Adult↗
PubMed1998

Timing of intrapartum ampicillin and prevention of vertical transmission of group B streptococcus.

OBJECTIVE: To evaluate the relationship between the time elapsed from the administration of ampicillin prophylaxis to delivery and its efficacy in interrupting intrapartum transmission of group B streptococcus. METHODS: During the 12-month study period, all women who came to the Virgen de las Nieves Hospital (Granada, Spain) for delivery were screened for group B streptococcus vaginal carriage by a pigment-detection culture-based procedure. Colonized women were treated with ampicillin (2 g intravenously), and the interval between ampicillin administration and delivery was recorded. Newborns from colonized mothers also were screened to detect group B streptococcus colonization. RESULTS: During the study period, 4525 women were admitted to the hospital for delivery and screened for group B streptococcus vaginal colonization. Group B streptococcus was detected in 543 women (12%), of whom 454 gave birth vaginally to 454 liveborn infants. Intrapartum ampicillin was given to 201 of these 454 women (44%), and 10% of the newborns from mothers who received intrapartum ampicillin prophylaxis were colonized by group B streptococcus. The relationship between timing of ampicillin administration and rate of neonatal group B streptococcal transmission was as follows: less than 1 hour before delivery, 46%; 1-2 hours, 29%; 2-4 hours, 2.9%; and more than 4 hours, 1.2%. Among the 253 mothers who received no intrapartum prophylaxis, colonization was found in 120 of their newborns (47%). CONCLUSION: When the time between the start of ampicillin prophylaxis and delivery is at least 2 hours, vertical transmission of group B streptococcus is minimized.

Ampicillin↗
PubMed1996

Influence of obstetric and perinatal care on perinatal mortality.

OBJECTIVE: Cases of perinatal death attributed to suboptimal perinatal care between 1979 and 1992 inclusive at a large, tertiary care center are reviewed. STUDY DESIGN: The study compared two periods: 1979-1985 and 1986-1992. The perinatal morbidity-mortality committee analyzed patient records for the mothers and neonates, delivery room records, the results of fetal autopsy, and histological sections of the placenta. RESULTS: In the first period, 21.5% of the deaths were found to have received suboptimal care; this figure declined 13.5% in the second period (P < 0.05). During the second period, antenatal, intranatal and postnatal care improved, as shown by the lower suboptimal care rate for antepartum (15.8% versus 9.8%; P < 0.05), intrapartum (49.2% versus 22.1%; P < 0.001) and postpartum death (19.9% versus 8.1%; P < 0.001). During both periods, fetal death during pregnancy made up the largest proportion of deaths attributed to suboptimal care, with 44 cases (43.1%) during 1979-1985, and 36 cases (64.3%) during 1986-1992 (P < 0.01). Of these cases, fetuses with intrauterine growth retardation were the most frequent recipients of suboptimal care (20 cases (45.5%) during the first period; 18 cases (50%) during the second period). CONCLUSION: Despite better prenatal care, the highest suboptimal care rate was due to suboptimal care during pregnancy, when some high risk situations were overlooked by the obstetrician.

Cesarean Section↗
PubMed1996

[Intrahepatic cholestasis of pregnancy. Maternofetal implications].

OBJECTIVE: To analyze a group of pregnancies complicated by intrahepatic cholestasis in order to favour an early recognition and to decrease maternal and fetal morbid-mortality. PATIENTS AND METHODS: Retrospective study of 46 pregnancies with intrahepatic gravidic cholestasis between 1990-94. We review the most relevant epidemiologic, clinical and biological features and the obstetric and perinatal results. The study group was compared with 1652 non complicated pregnancies (control group) from the same period of time. The statistic evaluation was made with t Student and chi 2. RESULTS: The incidence was 0.18% (mean age of 27.8 +/- 6.7 years) similar to the control group, and a greater rate of primiparity (p < 0.05) and twin pregnancies (p < 0.001). The most frequent symptom was pruritus, followed by choluria (23.9%) and signs of cutaneous scratching (17.3%). Only 5 patients (10.8%) had jaundice. The GPT was greater than 100 U/1 in 29 cases (63.1%) and the GOT in 17 (37%). In 25 pregnancies (54.3%) the alkaline phosphatase exceeded 600 U/L and 28 (60.8%) had bilirubin normal values. Urinary tract infections (26%) and preterm labor (17.3%) were significantly more frequent (p < 0.001) in patients with intrahepatic cholestasis of pregnancy, as well as induced labor rate and cesarean section percentages (p < 0.001). The neonatal prognosis was significantly worse, with 10 preterm babies, 6 with 5 minutes Apgar score lower than 7, and 3 perinatal deaths. All the patients recovered their normal status after delivery. CONCLUSIONS: In intrahepatic gravidic cholestasis moderate cytolysis, infrequent jaundice and cholestasis can be important. The pregnancies should be considered of high risk, and should be managed aggressively as soon as fetal maturity allows it.

Adult↗
PubMed1995

Efficacy of a universal screening program for the prevention of neonatal group B streptococcal disease.

Universal antepartum vaginal cultures for group B streptococcus (GBS) were initiated in a Spanish hospital in 1994 using Granada medium. Infants born to carriers were monitored closely, and blood, urine and mucocutaneous areas were cultured for GBS. Group B streptococcus was detected in 543 of 4,525 women (12%). Of these, 454 gave birth vaginally, of whom 201 (44%) received intrapartum ampicillin. Prophylaxis was not administered to 253 women (56%). In this group, infants of 120 women were colonized and 1 case of neonatal GBS disease occurred. Using this protocol, most GBS carriers with risk factors received intrapartum prophylaxis. This protocol also led to early identification of colonized newborns.

Female↗
PubMed1994

Strict glycemic control in women with pregestational insulin-dependent diabetes mellitus.

OBJECTIVE: To determine the efficacy of strict glycemic control in women with pregestational insulin-dependent diabetes mellitus (IDDM). METHODS: The records of 62 pregnant women with pregestational IDDM who had attended the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Virgen de las Nieves General Hospital, Granada, Spain, between 1982 and 1992, were reviewed. The women had received several daily doses of a mixture of rapid action (regular) and intermediate action insulin with the aim of keeping preprandial glucose levels lower than 95 mg/dl and postprandial glucose levels lower than 120 mg/dl. Perinatal outcomes were compared with those of a control group consisting of 96 randomly selected, normal, pregnant women who gave birth at approximately the same time. RESULTS: Mean glycemic profile in the first assay at an insulin dose of 33.1 +/- 15.9 IU/day was 153.7 +/- 52.3 mg/dl and the HbA1c was 7.7 +/- 2.3%. In the last assay before delivery patients received an insulin dose of 68.2 +/- 30.7 IU/day and had a mean glycemic profile of 94.4 +/- 18.1 mg/dl and an HbA1c of 5.9 +/- 1.4% (P < 0.001 for all parameters). The perinatal mortality of newborn infants of the diabetic mothers was 48 per 1000, and 11.3 per 1000 had some congenital malformations. CONCLUSIONS: Our results verify that strict glycemic control decreases the elevated perinatal mortality normally suffered by IDDM patients. However, if it is to reduce the number of congenital malformations, it must be initiated before the early gestational stages.

Adult↗
PubMed1993

Posthysterectomy wound infection. A review.

We reviewed the microorganisms isolated from gynecologic surgery wounds showing signs of infection, from January to December 1990. A total of 88 samples of abdominal wall exudates from as many patients who had undergone abdominal hysterectomy were studied. In 54 women (61.3%), cultures were positive and, in 26 specimens (48.1%), mixed aerobic-anaerobic flora were isolated. In 28 cases (51.9%), a single microorganism was isolated, the most frequent being Staphylococcus aureus, followed by Mycoplasma hominis and Escherichia coli. Mycoplasma hominis was unexpectedly frequent, appearing in five women with wall abscess and fever.

Bacteria↗