Posterior uterine rupture in a woman with a previous Cesarean delivery

A 33-year-old primipara with a previous low transverse Cesarean delivery underwent labor induction at 41 weeks' gestation with a 10-mg dinoprostone vaginal insert. Eleven hours later, with the cervix fully dilated, an emergency Cesarean delivery was performed because of repetitive variable decelerations followed by fetal bradycardia. A posterior uterine wall rupture extending from the fundus to the vagina was repaired in layers. The neonate had an Apgar score of 2 and 4 and expired on the 7th day of life.

Glioblastoma multiforme in pregnancy

Brain tumors in pregnancy are uncommon occurrences. A 48-year-old female at 36 2/7 weeks of gestation presented with right-sided weakness and parasthesias, a facial droop, and an unsteady gait. Brain imaging studies revealed a left-sided parietal lesion impinging upon the lateral ventricle. She underwent a cesarean delivery and then a craniotomy with resection of a glioblastoma multiforme two days later. Despite treatment with radiation and chemotherapy, she died nine months later. Glioblastoma multiforme is a rare diagnosis during pregnancy which may present as a neurologic emergency.

Fermi surface and van Hove singularities in the itinerant Metamagnet Sr3Ru2O7

The low-energy electronic structure of the itinerant metamagnet Sr3Ru2O7 is investigated by angle-resolved photoemission and density-functional calculations. We find well-defined quasiparticle bands with resolution-limited linewidths and Fermi velocities up to an order of magnitude lower than in single layer Sr2RuO4. The complete topography, the cyclotron masses, and the orbital character of the Fermi surface are determined, in agreement with bulk sensitive de Haas-van Alphen measurements. An analysis of the dxy band dispersion reveals a complex density of states with van Hove singularities near the Fermi level, a situation which is favorable for magnetic instabilities.

Evolution of the Fermi surface and quasiparticle renormalization through a van Hove singularity in Sr2-yLayRuO4

We employ a combination of chemical substitution and angle resolved photoemission spectroscopy to prove that the Fermi level in the gamma band of Sr(2-y)La(y)RuO(4) can be made to traverse a van Hove singularity. Remarkably, the large mass renormalization has little dependence on either k or doping. By combining the results from photoemission with thermodynamic measurements on the same batches of crystals, we deduce a parametrization of the full many-body quasiparticle dispersion in Sr(2)RuO(4) which extends from the Fermi level to approximately 20 meV above it.

Omega-3 fatty acids and decidual cell prostaglandin production in response to the inflammatory cytokine IL-1beta

OBJECTIVE

The objective of this study was to determine the effect of omega-3 fatty acids (eicosapentaenoic acid [EPA]; docosahexaenoic acid [DHA]) on prostaglandin production and prostanoid enzyme expression in cultured decidual cells exposed to interleukin-1beta (IL-1beta), a cytokine that plays a major role in inflammation.

STUDY DESIGN

Decidua was obtained from human placentas of nonlaboring patients at term cesarean delivery (N = 6) and cultured by using standard cell culture techniques. Cells were preincubated in defined media with various concentrations of vehicle, DHA, or EPA for 1 hour. IL-1beta (10 ng/mL) was then added to the media, and experiments were terminated 12 hours after exposure to IL-1beta. Prostaglandin E2 (PGE2) and PGF2alpha concentrations in conditioned media were measured by enzyme-linked immunosorbent assay; cyclooxygenase-1 (COX-1), COX-2, microsomal prostaglandin E synthase (mPGES)-1, mPGES-2, and 15-hydroxy prostaglandin dehydrogenase (PGDH) expression were quantified by real-time polymerase chain reaction and immunoblotting. Groups were compared with the use of Student t test, with significance defined as P < .05.

RESULTS

Preincubation with DHA decreased prostaglandin production by up to 80% when compared with controls. DHA decreased both mPGES-1 and -2 messenger RNA expression by approximately 50% (P = .02). Preincubation in DHA or EPA had no effect on COX-1, COX-2, and PGDH messenger RNA or protein expression.

CONCLUSION

Under conditions simulating inflammation, supplementation with omega-3 fatty acids decreases PGE2 and PGF2alpha production in cultured decidual cells. The reduction in prostaglandin production was associated with a decreased expression of mPGES-1 and -2. These findings suggest a mechanism by which omega-3 fatty acid supplementation decreases the incidence of preterm birth in high-risk patients.

Formation of a Nematic Fluid at High Fields in Sr3Ru2O7

In principle, a complex assembly of strongly interacting electrons can self-organize into a wide variety of collective states, but relatively few such states have been identified in practice. We report that, in the close vicinity of a metamagnetic quantum critical point, high-purity strontium ruthenate Sr3Ru2O7 possesses a large magnetoresistive anisotropy, consistent with the existence of an electronic nematic fluid. We discuss a striking phenomenological similarity between our observations and those made in high-purity two-dimensional electron fluids in gallium arsenide devices.

Thermal conductivity in the vicinity of the quantum critical end point in Sr3Ru2O7

Thermal conductivity of Sr3Ru2O7 was measured down to 40 mK and at magnetic fields through the quantum critical end point at Hc=7.85 T. A peak in the electrical resistivity as a function of the field was mimicked by the thermal resistivity. In the limit as T-->0 K, we find that the Wiedemann-Franz law is satisfied to within 5% at all fields, implying that there is no breakdown of the electron despite the destruction of the Fermi liquid state at quantum criticality. A significant change in disorder [from rho0(H=0 T)=2.1 to 0.5 microOmega cm] does not influence our conclusions. At finite temperatures, the temperature dependence of the Lorenz number is consistent with ferromagnetic fluctuations causing the non-Fermi liquid behavior as one would expect at a metamagnetic quantum critical end point.

Fermi surface and quasiparticle excitations of Sr2RhO4

The electronic structure of the layered 4d transition metal oxide Sr2RhO4 is investigated by angle resolved photoemission. We find well-defined quasiparticle excitations with a highly anisotropic dispersion, suggesting a quasi-two-dimensional Fermi-liquid-like ground state. Markedly different from the isostructural Sr2RuO4, only two bands with dominant Rh 4dxz,zy character contribute to the Fermi surface. A quantitative analysis of the photoemission quasiparticle band structure is in excellent agreement with bulk data. In contrast, it is found that state-of-the-art density functional calculations in the local density approximation differ significantly from the experimental findings.

Nested fermi surface and electronic instability in Ca3Ru2O7

High-resolution angular resolved photoemission data reveal well-defined quasiparticle bands of unusually low weight, emerging in line with the metallic phase of Ca(3)Ru(2)O(7) below approximately 30 K . At the bulk structural phase transition temperature of 48 K, we find clear evidence for an electronic instability, gapping large parts of the underlying Fermi surface that appears to be nested. Metallic pockets are found to survive in the small, non-nested sections, constituting a low-temperature Fermi surface with 2 orders of magnitude smaller volume than in all other metallic ruthenates. The Fermi velocities and volumes of these pockets are in agreement with the results of complementary quantum oscillation measurements on the same crystal batches.

Combined sonographic and endoscopic umbilical cord occlusion in twin and triplet gestations

OBJECTIVE

To review our experience with a minimally invasive technique for umbilical cord occlusion as a method of selective feticide in monochorionic sets.

STUDY DESIGN

Umbilical cord occlusion was completed using 3 mm bipolar cautery under ultrasound guidance (3D/4D, n = 6; 2D, n = 6) with pre and post ligation endoscopic evaluation.

RESULTS

12 cases of monochorionic sets where selective feticide was performed were identified during the period 2000 to present. There were four triplet and eight twin gestations in the study cohort. Median interval from intervention to delivery was 16 weeks (range, 5-19). All co-twins survived the procedure and 15 of 16 were delivered after 33 weeks.

CONCLUSIONS

Umbilical cord occlusion in monochorionic sets can be accomplished in a minimally invasive manner with combined endoscopic and ultrasound guidance in both twin and triplet pregnancies.

Phase bifurcation and quantum fluctuations in Sr3Ru2O7

The bilayer ruthenate Sr3Ru2O7 has been cited as a textbook example of itinerant metamagnetic quantum criticality. However, recent studies of the ultrapure system have revealed striking anomalies in magnetism and transport in the vicinity of the quantum critical point. Drawing on fresh experimental data, we show that the complex phase behavior reported here can be fully accommodated within the framework of a simple Landau theory. We discuss the potential physical mechanisms that underpin the phenomenology, and assess the capacity of the ruthenate system to realize quantum tricritial behavior.

Endoscopic closure of fetal membrane defects: comparing iatrogenic versus spontaneous rupture cases

OBJECTIVE

Currently, physicians manage preterm premature rupture of membranes (PPROM) by expectant management or termination of the gestation. A therapy aimed at sealing membranes would be optimal to maintain the pregnancy and achieve a normal neonate. Our objective was to compare an endoscopic technique for intrauterine closure of fetal membrane defects after both iatrogenic and spontaneous rupture of membranes.

METHODS

Our technique was performed on four patients experiencing PPROM spontaneously and four patients after genetic amniocentesis. Intrauterine endoscopy allowed direct visualization of membrane defects. Rapid sequential injections of platelets, fibrin glue and powdered collagen slurry were administered at the site of the defect and of trocar placement. Sonography for amniotic fluid index, nitrazine and fern testing and pad count were performed after each procedure at three intervals: immediately post-procedure, and after 24 and 48 h.

RESULTS

Eight patients underwent endoscopic intrauterine sealing of ruptured membranes between 16 and 24 weeks of gestation: four were spontaneous ruptures and four were ruptures post-amniocentesis. In the post-amniocentesis group, three patients delivered viable infants at 26, 32 and 34 weeks. In one patient, the membranes ruptured again 12 h after the sealing procedure and she decided to undergo termination of pregnancy. Of the four spontaneous rupture patients, two experienced preterm labor and delivery within 2 days of the procedure. One patient was diagnosed with fetal demise 12 h post-procedure, and one patient delivered a neonate at 31 weeks of gestation with severe respiratory distress syndrome.

CONCLUSIONS

This technique for sealing ruptured membranes is effective after amniocentesis, but may not be of benefit with spontaneous rupture.

Mechanisms of abruption-induced premature rupture of the fetal membranes: Thrombin enhanced decidual matrix metalloproteinase-3 (stromelysin-1) expression

OBJECTIVE

The aim of the study was to evaluate thrombin and progestin effects on matrix metalloproteinase-3 expression in term decidual cells as a mechanism of abruption-related preterm delivery.

STUDY DESIGN

Decidual cells were isolated by standard techniques, purified to homogeneity, grown to confluence, and passaged. Cultures were primed with 10 (-8) M estradiol or estradiol plus 10 (-7) progestin and then incubated in a defined medium with corresponding steroid(s) plus or minus thrombin or the protease-activated thrombin receptor-1 agonist for 24 hours. Secreted matrix metalloproteinase-3 levels were assessed by enzyme-linked immunosorbent assay, and immunoblotting and messenger RNA levels were measured by Northern blotting and quantitative reverse transcription-polymerase chain reaction.

RESULTS

Immunoreactive matrix metalloproteinase-3 levels were inhibited 66% by estradiol plus progestin versus estradiol ( P < .05). Thrombin elicited a dose-dependent reversal in this progestin inhibition, producing a 2.5-fold increase at 2.5 U/mL ( P < .05) that attained 33% of matrix metalloproteinase-3 levels in parallel incubations with estradiol plus thrombin. Protease-activated thrombin receptor-1 agonist mimicked 60% of thrombin-enhanced matrix metalloproteinase-3 output. Immunoblotting validated the enzyme-linked immunosorbent assay results. Northern blotting and quantitative reverse transcription-polymerase chain reaction demonstrated corresponding effects on steady-state messenger RNA levels.

CONCLUSION

Abruption-generated thrombin promotes preterm delivery by mediating fetal membrane extracellular matrix degradation via enhanced decidual cell matrix metalloproteinase-3 expression, whereas progesterone blunts this thrombin-induced effect.

Disorder-Sensitive Phase Formation Linked to Metamagnetic Quantum Criticality

Condensed systems of strongly interacting electrons are ideal for the study of quantum complexity. It has become possible to promote the formation of new quantum phases by explicitly tuning systems toward special low-temperature quantum critical points. So far, the clearest examples have been appearances of superconductivity near pressure-tuned antiferromagnetic quantum critical points. We present experimental evidence for the formation of a nonsuperconducting phase in the vicinity of a magnetic field-tuned quantum critical point in ultrapure crystals of the ruthenate metal Sr3Ru2O7, and we discuss the possibility that the observed phase is due to a spin-dependent symmetry-breaking Fermi surface distortion.

de Haas-van Alphen effect across the metamagnetic transition in Sr3Ru2O7

We report a study of the de Haas-van Alphen (dHvA) effect on the itinerant metamagnet Sr3Ru2O7. Extremely high sample purity allows the observation of dHvA oscillations both above and below the metamagnetic transition field of 7.9 T. The quasiparticle masses are fairly large away from the transition, and are enhanced by up to an extra factor of 3 as the transition is approached, but the Fermi surface topography change is quite small. The results are qualitatively consistent with a field-induced Stoner transition in which the mass enhancement is the result of critical fluctuations.

Multiple first-order metamagnetic transitions and quantum oscillations in ultrapure Sr3Ru2O7

We present measurements on ultraclean single crystals of the bilayered ruthenate metal Sr3Ru2O7, which has a magnetic-field-tuned quantum critical point. Quantum oscillations of differing frequencies can be seen in the resistivity both below and above its metamagnetic transition. This frequency shift corresponds to a small change in the Fermi surface volume that is qualitatively consistent with the small moment change in the magnetization across the metamagnetic transition. Very near the metamagnetic field, unusual behavior is seen. There is a strong enhancement of the resistivity in a narrow field window, with a minimum in the resistivity as a function of temperature below 1 K that becomes more pronounced as the disorder level decreases. The region of anomalous behavior is bounded at low temperatures by two first-order phase transitions. The implications of the results are discussed.

A coherent three-dimensional Fermi surface in a high-transition-temperature superconductor

All conventional metals are known to possess a three-dimensional Fermi surface, which is the locus in reciprocal space of the long-lived electronic excitations that govern their electronic properties at low temperatures. These excitations should have well-defined momenta with components in all three dimensions. The high-transition-temperature (high-T(c)) copper oxide superconductors have unusual, highly two-dimensional properties above the superconducting transition. This, coupled with a lack of unambiguous evidence for a three-dimensional Fermi surface, has led to many new and exotic models for the underlying electronic ground state. Here we report the observation of polar angular magnetoresistance oscillations in the overdoped superconductor Tl2Ba2CuO6+delta in high magnetic fields, which firmly establishes the existence of a coherent three-dimensional Fermi surface. Analysis of the oscillations reveals that at certain symmetry points, however, this surface is strictly two-dimensional. This striking form of the Fermi surface topography, long-predicted by electronic band structure calculations, provides a natural explanation for a wide range of anisotropic properties both in the normal and superconducting states. Our data reveal that, despite their extreme electrical anisotropy, the high-T(c) materials at high doping levels can be understood within a framework of conventional three-dimensional metal physics.

Evolution of Fermi-liquid interactions in Sr2RuO4 under pressure

We have measured the temperature and field dependence of the resistivity of the unconventional superconductor Sr2RuO4 at pressures up to 3.3 GPa. Using the Shubnikov-de Haas effect, we find that the Fermi surface sheet believed to be primarily responsible for superconductivity becomes more two-dimensional with increasing pressure, a surprising result that is, however, consistent with a recent model of orbital-dependent superconductivity in this system. Many-body enhancements and the superconducting transition temperature all fall gradually with increasing pressure, contrary to previous suggestions of a ferromagnetic quantum critical point at approximately 3 GPa.

Heat transport in a strongly overdoped cuprate: Fermi liquid and a pure d-wave BCS superconductor

The transport of heat and charge in the overdoped cuprate superconductor Tl(2)Ba2CuO(6+delta) was measured down to low temperature. In the normal state, obtained by applying a magnetic field greater than the upper critical field, the Wiedemann-Franz law is verified to hold perfectly. In the superconducting state, a large residual linear term is observed in the thermal conductivity, in quantitative agreement with BCS theory for a d-wave superconductor. This is compelling evidence that the electrons in overdoped cuprates form a Fermi liquid, with no indication of spin-charge separation.

Sensitivity to disorder of the metallic state in the ruthenates

We report the results of transport measurements on SrRuO3, Sr3Ru2O7, and CaRuO3. In SrRuO3 and Sr3Ru2O7, our findings are consistent with the predictions of Fermi liquid theory, in contrast to previous reports based on samples with much shorter mean free paths. In CaRuO3, however, a T1.5 power law is seen in the resistivity in the high purity samples studied here. Our work gives concrete evidence that even the metallic state of the ruthenates is highly sensitive to disorder.

Magnetic field-tuned quantum criticality in the metallic ruthenate Sr3Ru2O7

The concept of quantum criticality is proving to be central to attempts to understand the physics of strongly correlated electrons. Here, we argue that observations on the itinerant metamagnet Sr3Ru2O7 represent good evidence for a new class of quantum critical point, arising when the critical end point terminating a line of first-order transitions is depressed toward zero temperature. This is of interest both in its own right and because of the convenience of having a quantum critical point for which the tuning parameter is the magnetic field. The relationship between the resultant critical fluctuations and novel behavior very near the critical field is discussed.

Metamagnetism and critical fluctuations in high quality single crystals of the bilayer ruthenate Sr3Ru2O7

We report the results of low temperature transport, specific heat, and magnetization measurements on high quality single crystals of the bilayer perovskite Sr3Ru2O7, which is a close relative of the unconventional superconductor Sr2RuO4. Metamagnetism is observed, and transport and thermodynamic evidence for associated critical fluctuations is presented. These relatively unusual fluctuations might be pictured as variations in the Fermi surface topography itself.

Reconstruction from small-angle neutron scattering measurements of the real space magnetic field distribution in the mixed state of Sr2RuO4

We have measured the diffracted neutron scattering intensities from the square magnetic flux lattice in the perovskite superconductor Sr2RuO4, which is thought to exhibit p-wave pairing with a two-component order parameter. The relative intensities of different flux lattice Bragg reflections over a wide range of field and temperature have been shown to be inconsistent with a single component Ginzburg-Landau theory but qualitatively agree with a two-component p-wave Ginzburg-Landau theory.

Detailed topography of the fermi surface of Sr2RuO4

We apply a novel analysis of the field and angle dependence of the quantum-oscillatory amplitudes in the unconventional superconductor Sr2RuO4 to map its Fermi surface (FS) in unprecedented detail and to obtain previously inaccessible information on the band dispersion. The three quasi-2D FS sheets not only exhibit very diverse magnitudes of warping, but also entirely different dominant warping symmetries. We use the data to reassess recent results on c-axis transport phenomena.

Dielectric characterization of thermodynamic first order events in model frozen systems intended for lyophilization

The degree and ease with which permanent dipoles in a frozen sample orient in an applied electric field is affected during thermal transitions. This motion can be monitored with dielectric analysis (DEA) at low AC frequencies (< approximately 300,000 Hz). The systems characterized with respect to their behavior in the frozen state consisted of common lyophile excipients in aqueous solutions known to exhibit typical thermodynamic first order transitions. Prior to freezing, solution samples were placed on an interdigitated electrodes and served as the dielectric component of the resulting capacitor. Plots of derivative of dielectric permittivity with respect to time (or temperature) showed the presence of frequency independent peaks (signifying a first order event) at temperatures that coincided with eutectic temperatures (ca. -22 degrees C for sodium chloride-water and ca. -5 degrees C for mannitol-water), amorphous to crystalline transition temperatures (ca. -25 degrees C for mannitol-water), and/or freezing point depression values in water. The values obtained by DEA correlated well with differential scanning calorimetry (DSC) and literature values. DEA appears to offer added insight over established techniques by not only determining the temperature at which these events occur, but also by defining the thermodynamic order of the event.

Prediction of lyophile collapse temperature by dielectric analysis

A new method for predicting lyophile collapse temperatures based upon dielectric analysis (DEA) of frozen two component systems is presented. The method, called the take off frequency model (TOF), relies both on the inherent ability of DEA to detect molecular motion and on the abrupt change in viscosity experienced by a frozen sample undergoing a glass-liquid transition. Collapse temperatures for binary glass forming systems (an antibiotic, sucrose, trehalose, or sorbitol, with water) were in good agreement with the values reported in the literature. DEA was easily able to detect glass transitions poorly defined by differential scanning calorimetry (DSC). Conservative lyophilization cycles for simple systems can be quickly determined on the basis of the TOF model.

A simple method of rapid freezing adequately preserves brain tissue for immunocytochemistry, light and electron microscopic examination

A simple and reproducible method for cryopreservation of brain tissue from patients with Alzheimer's disease is described. Fresh brain slices (1 cm thick) obtained less than 6 h postmortem are placed in sealed plastic bags, sandwiched between 0.3-cm-thick aluminium sheets, and frozen by placing the entire "sandwich" between layers of dry ice pellets. The frozen brain slices are stored at -85 degrees C. Specific anatomic areas can be retrieved at any time for light and electron microscopic, immunocytochemical, autoradiographic and neurochemical studies.

The effects of freeze-drying and rehydration on cancellous bone

Processing technique significantly affects the strength and stiffness of bone for use as a structural alloimplant in reconstructive surgery. The effects of the rehydration of freeze-dried human cancellous bone were studied using 14-mm-diameter cancellous dowels taken from matched cadaveric sites. Three different methods of rehydration were evaluated and compared with unrehydrated freeze-dried and frozen grafts. All samples were biomechanically tested in anatomically matched pair groups to determine compressive strength and stiffness. The strength of each tested graft was expressed as a percentage of its matched pair control. Freeze-dried grafts rehydrated for 24 hours compared with frozen grafts showed no significant difference in mean compressive strength (92.6% +/- 13.3% of control). Analysis of in vacuo versus ex vacuo rehydration at one hour showed a 38% greater mean compressive strength and a 42% greater mean stiffness for the ex vacuo group. Unrehydrated grafts appeared to be both stronger and stiffer than their rehydrated counterparts. These results suggest that the rehydration of freeze-dried grafts may adversely affect graft strength and stiffness. Rehydration under a negative pressure may proceed more rapidly than the process at atmospheric pressures. These findings limit the acceptability of freeze-dried grafts as structural implants.

Effect of high-frequency ventilation on the development of alveolar edema in premature monkeys at risk for hyaline membrane disease

High-frequency oscillatory ventilation (HFOV) permits adequate gas exchange but avoids the large phasic pressure-volume excursions of conventional mechanical ventilation (CMV); such avoidance may reduce the lung injury associated with hyaline membrane disease (HMD). We hypothesized that premature monkeys ventilated from birth with HFOV would have reduced lung injury compared to those assigned to CMV. Macaca nemestrina were delivered at 134 days (80% of term gestation) and ventilated from the first breath with either HFOV (n = 10) or CMV (n = 10). The mean airway pressure (Paw) was kept at 15 cm H2O pressure in HFOV animals; in CMV animals Paw was increased from 8 cm H2O at 2 h to 13 cm H2O at 6 h to prevent hypoxemia. At the conclusion of the 6-h experiment the HFOV animals had better oxygenation (p less than 0.05) and less evidence of HMD by chest radiograph (p less than 0.05). At 6 h of age a piece of the right middle lung lobe was removed, divided, and placed in fixatives for light and transmission electron microscopy. The lungs were subsequently inflated to 30 cm H2O pressure, and the right lower lobe was rapidly frozen in situ for morphometric studies. The proportion of peripheral lung tissue occupied by clear alveoli was greater in HFOV animals (66.3 +/- 14.8%) than in those assigned to CMV (44.2 +/- 16.9%, p less than 0.01); less alveolar debris and fluid was present in the HFOV animals (12.7 +/- 9.9%) compared with CMV animals (27.1 +/- 12.5%, p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)