Galileo at Io: results from high-resolution imaging.

During late 1999/early 2000, the solid state imaging experiment on the Galileo spacecraft returned more than 100 high-resolution (5 to 500 meters per pixel) images of volcanically active Io. We observed an active lava lake, an active curtain of lava, active lava flows, calderas, mountains, plateaus, and plains. Several of the sulfur dioxide-rich plumes are erupting from distal flows, rather than from the source of silicate lava (caldera or fissure, often with red pyroclastic deposits). Most of the active flows in equatorial regions are being emplaced slowly beneath insulated crust, but rapidly emplaced channelized flows are also found at all latitudes. There is no evidence for high-viscosity lava, but some bright flows may consist of sulfur rather than mafic silicates. The mountains, plateaus, and calderas are strongly influenced by tectonics and gravitational collapse. Sapping channels and scarps suggest that many portions of the upper approximately 1 kilometer are rich in volatiles.

The Zavanelli maneuver: a different perspective.

Some obstetricians recommend the Zavanelli maneuver to resolve shoulder dystocia. Descriptions in the literature report an almost automatic ease in performance of the maneuver. We report a case of severe shoulder dystocia in which management with the Zavanelli maneuver and immediate cesarean was extremely difficult. The procedure involved exact reversal of all the cardinal movements of labor, and the delivery required terbutaline, general anesthesia, and added personnel to ensure successful extraction of the fetus. A delivery requiring the Zavanelli maneuver can be difficult to perform and may be worsened by insufficient personnel and inexact reversal of all the cardinal movements of labor.

Massive septic pelvic thrombophlebitis.

BACKGROUND: Septic pelvic thrombophlebitis is a major complication of endometritis. The thrombi commonly occur in the uterine and/or ovarian veins and may extend into the inferior vena cava. CASE: Following vaginal delivery, a 19-year-old woman, gravida 2, developed postpartum septic pelvic thrombophlebitis extending from the right ovarian vein up to the diaphragm and down to the femoral vein. The patient was treated successfully with heparin and antibiotics, and eventually was discharged on oral anticoagulants for an extended period. Follow-up revealed complete resolution of the thrombus. CONCLUSION: Septic pelvic thrombophlebitis is not limited to the pelvis and lower abdominal vessels.

Single-dose ampicillin prophylaxis does not eradicate enterococcus from the lower genital tract.

OBJECTIVES: To determine the carriage rate of enterococcus in the lower genital tract of women having a cesarean delivery and to determine whether a single 2-g intraoperative dose of ampicillin eradicates enterococcus from the lower genital tract. METHODS: Lower genital tract cultures were taken in 84 women who were in labor or had ruptured membranes and who were about to have an indicated cesarean delivery. The subjects were randomized to receive either a single 2-g dose of ampicillin or a cephalosporin as prophylaxis. Cultures were repeated 24 hours postpartum. RESULTS: Enterococcus was isolated preoperatively in 33 subjects (39.3%) and postoperatively in 36 (42.9%). The enterococcus was eradicated in five of 17 women (29.5%) who received ampicillin. CONCLUSION: These results suggest that a single 2-g dose of ampicillin does not eradicate enterococcus from the lower genital tract.

Coarctation of the abdominal aorta in pregnancy: diagnosis by magnetic resonance imaging.

BACKGROUND: Coarctation of the aorta is rare, affecting one per 2000-3000 women. Abdominal coarctation is more commonly identified in women than in men, but only two cases have been reported in pregnancy. CASE: A 26-year-old woman was diagnosed with hypertension at 15 years of age. Her blood pressure was controlled adequately with beta-blockers. During her pregnancy, she was found to have coarctation of the abdominal aorta by magnetic resonance imaging. CONCLUSION: Magnetic resonance imaging is a safe, reliable means by which to confirm clinically suspected coarctation of the aorta during pregnancy.

Roseola infantum in pregnancy. A case report.

Roseola infantum (exanthem subitum) was first described as a specific syndrome by Zahorsky in 1913. It is a benign disease that occurs almost exclusively in infants and young children (six months to three years of age). We report a case of roseola in a pregnant woman. We were unable to find any prior reports of roseola in pregnancy. The classic presentation of roseola is characterized by high temperatures (103-105 degrees F) that last 3-5 days and resolve by crisis followed by the appearance of a morbilliform rash that lasts a few hours to a few days. The infectious agent is human herpesvirus-6. We recommend the addition of roseola to the differential diagnosis of rashes that occur in pregnancy. The potential danger to the fetus from this virus is unknown.

Ex vivo human placental transfer and the vasoactive properties of hydralazine.

OBJECTIVE: The purpose of this study was to determine the placental transfer and fetal vascular effects of hydralazine in an ex vivo human placental system. STUDY DESIGN: Nine placentas from uncomplicated term vaginal or cesarean deliveries were studied by means of the ex vivo single-cotyledon perfusion system. Antipyrine was used for the reference compound in the determination of the clearance index of hydralazine. Fetal vascular effects of hydralazine were determined by the effects on the perfusion pressure of the fetal artery in a constant-flow open system. Variations in fetal pressure were analyzed with the 1-sample Student t test. RESULTS: The clearance index of hydralazine ranged from 0.61 +/- 0. 18 to 0.73 +/- 0.14. The accumulation of hydralazine in the recirculated fetal compartment was linear in relationship to the maternal concentration. Fetal pressure changes were noted in 6 of the 9 placentas, or 66.6%. The mean change in pressure was -4.1 +/- 4.4 mm Hg (P =.0231). CONCLUSIONS: Hydralazine readily crosses the ex vivo human placental perfusion system.

Screening for hepatitis B among pregnant patients in a rural population.

From February 1988 to April 1990, we collected blood for hepatitis B surface antigen (HBsAg) from all women coming to the Texas Tech University Health Science Center in Lubbock for prenatal care. These patients were from rural western Texas and eastern New Mexico. They were also screened for hepatitis B risk factors, as outlined by the Centers for Disease Control. We reviewed the prenatal records of all HBsAg-positive women. Six of 4452 women (0.13%) had a positive HBsAg test. Four of the six women had identifiable risk factors and two did not; two were non-Hispanic caucasian (Anglo), two were Hispanic, and two were black. Anglos comprised 49.5% of the rural population, Hispanics 34.9%, blacks 12.8%, and Asians 2.8%. No Asian women were positive for HBsAg. The prevalence of HBsAg positivity was lower in this rural population than in previously reported urban populations. While the prevalence in the studied blacks and Hispanics was similar to that in previous reports, the prevalence in the rural Anglos was lower.

Ex vivo human placental transfer of rifampin and rifabutin.

OBJECTIVE: The purpose of this study was to determine the ex vivo human placental transfer of rifampin and rifabutin. METHODS: Seven placentas from uncomplicated term vaginal or cesarean deliveries were studied utilizing the ex vivo single cotyledon perfusion system. Antipyrine was used for the reference compound in the determination of the clearance indices of rifampin and rifabutin. RESULTS: The clearance indices of rifampin at maternal concentrations of 1.0 and 10.0 mug/ml were 0.12 +/- 0.05 and 0.12 +/- 0.11, respectively. The clearance indices of rifabutin at maternal concentrations of 1.0 and 10.0 mug/ml were 0.44 +/- 0.11 and 0.37 +/- 0.15, respectively. CONCLUSIONS: Because of its greater lipophilicity, rifabutin was found to have a greater clearance than rifampin. However, because of rifabutin's trend toward greater deposition in tissue, there was proportionately less accumulation of rifabutin in the fetal circulation when compared to rifampin.

Endometritis after cesarean: the effect of age.

In this study, we compared the rate of endometritis after cesarean section in two age groups. The first group consisted of patients who were 17 years old or younger (teenage group) and the second group of patients were 35 years of age or older (advanced maternal age group). Patients in each group were matched for length of labor, length of rupture of membranes, and the use of prophylactic antibiotics. In the teenage group, 18 of 41 (43.9%) developed endometritis compared with 6 of 41 (14.6%) in the advanced maternal age group (P < 0.003). This study supports the concept that young age is a risk factor for endometritis after cesarean section.

Gentamicin levels in pregnant women with pyelonephritis.

This study was performed at University Medical Center, Lubbock, Texas, from July 1989 to June 1990. We obtained serum gentamicin peak and trough levels in 23 pregnant women with pyelonephritis. The patients were given a loading dose of 2 mg/kg gentamicin, followed by 1.5 mg/kg gentamicin adjusted for obesity every 8 hours. Peak levels were obtained 1 hour after the fifth dose and trough levels were drawn 30 minutes before the sixth dose. Statistical analysis was performed using chi 2 analysis. The mean (+/- SD) peak gentamicin level was 2.7 +/- 1.4 micrograms/mL and the mean trough level was 0.5 +/- 0.3 micrograms/mL. Twenty-two of 23 (96%) patients had peak levels 5 micrograms/mL and 1 of 23 (4%) patients had peak levels between 5 and 10 micrograms/mL. The mean peak gentamicin level in pregnancy is significantly less than in puerperal women (2.70 versus 5.78; P < 0.000001). We conclude that the majority of pregnant women treated for pyelonephritis with standard doses of gentamicin do not achieve therapeutic levels. Also, peak gentamicin levels are significantly below that reported for puerperal women.

Uterine contractions after antibiotic therapy for pyelonephritis in pregnancy.

OBJECTIVE: The purpose of our study was to investigate the pathogenesis of preterm labor in pyelonephritis, we determined the number of uterine contractions occurring in patients with pyelonephritis before and after antibiotic therapy. STUDY DESIGN: We recorded the uterine contractions before and after antibiotic administration in 30 patients with acute pyelonephritis at Lyndon B. Johnson Hospital in Houston. Exclusion criteria were cervical dilatation > or = 4 cm, < 26 weeks' gestation, antibiotics within 7 days, clinical intraamniotic infection, rupture of membranes, or other maternal infection. Statistical analysis was by Kruskal-Wallis analysis of variance and Wilcoxon rank sum tests. RESULTS: The patients averaged eight contractions per hour on admission. The contraction rate significantly increased in hours +1 to +4 after antibiotic administration. The increase in uterine contractility occurred in patients with urinary tract gram-negative isolates. CONCLUSIONS: Pregnant women with pyelonephritis resulting from gram-negative bacteria increase their rate of uterine contractility after antibiotic treatment. This observation may be important in understanding the pathogenesis of preterm labor in pyelonephritis.