Peripartal management of dichorial twin pregnancy in a bicornuate bicollis uterus: a case report and review of the literature.

INTRODUCTION: The management of a pregnancy in a bicornuate uterus is particularly challenging. A bicornuate uterus is a rare occurrence and a twin pregnancy in a bicornuate uterus even more rare. These pregnancies call for intensive diagnostic investigation and interdisciplinary care. CASE PRESENTATION: We report on a 27-year-old European woman patient (gravida I, para 0) with a simultaneous pregnancy in each cavity of a bicornuate bicollis uterus after embryo transfer. The condition was confirmed by hysteroscopy and laparoscopy. Several unsuccessful in vitro fertilization (IVF) attempts had been performed earlier before embryo transfer in each cornus. After a physiological course of pregnancy with differential screening at 12 + 6 weeks and 22 + 0 weeks of gestation, the patient presented with therapy-resistant contractions at 27 + 2 weeks. This culminated in the uncomplicated spontaneous delivery of the leading fetus and delayed spontaneous delivery of the second fetus. DISCUSSION: Only 16 cases of twin pregnancy in a bicornuate unicollis uterus have been reported worldwide and only 6 in a bicornuate bicollis uterus. The principal risks in such pregnancies are preterm labor, intrauterine growth restriction, malpresentation and preeclampsia. These typical risk factors of a twin pregnancy are greatly potentiated in the above mentioned setting. CONCLUSION: A twin pregnancy in the presence of a uterine malformation is rare and difficult to manage. These rare cases must be collected and reported in order to work out algorithms of monitoring and therapy as well as issue appropriate recommendations for their management.

Voltage modulates halothane-triggered Ca2+ release in malignant hyperthermia-susceptible muscle.

Malignant hyperthermia (MH) is a fatal hypermetabolic state that may occur during general anesthesia in susceptible individuals. It is often caused by mutations in the ryanodine receptor RyR1 that favor drug-induced release of Ca2+ from the sarcoplasmic reticulum. Here, knowing that membrane depolarization triggers Ca2+ release in normal muscle function, we study the cross-influence of membrane potential and anesthetic drugs on Ca2+ release. We used short single muscle fibers of knock-in mice heterozygous for the RyR1 mutation Y524S combined with microfluorimetry to measure intracellular Ca2+ signals. Halothane, a volatile anesthetic used in contracture testing for MH susceptibility, was equilibrated with the solution superfusing the cells by means of a vaporizer system. In the range 0.2 to 3%, the drug causes significantly larger elevations of free myoplasmic [Ca2+] in mutant (YS) compared with wild-type (WT) fibers. Action potential-induced Ca2+ signals exhibit a slowing of their time course of relaxation that can be attributed to a component of delayed Ca2+ release turnoff. In further experiments, we applied halothane to single fibers that were voltage-clamped using two intracellular microelectrodes and studied the effect of small (10-mV) deviations from the holding potential (-80 mV). Untreated WT fibers show essentially no changes in [Ca2+], whereas the Ca2+ level of YS fibers increases and decreases on depolarization and hyperpolarization, respectively. The drug causes a significant enhancement of this response. Depolarizing pulses reveal a substantial negative shift in the voltage dependence of activation of Ca2+ release. This behavior likely results from the allosteric coupling between RyR1 and its transverse tubular voltage sensor. We conclude that the binding of halothane to RyR1 alters the voltage dependence of Ca2+ release in MH-susceptible muscle fibers such that the resting membrane potential becomes a decisive factor for the efficiency of the drug to trigger Ca2+ release.

Uniform polymer microspheres: monodispersity criteria, methods of formation and applications.

For many applications, polymer microspheres (MS) should possess a monodisperse size distribution. With such uniformity they are able to deliver precise amounts of drug per MS, optimize the release kinetics of an encapsulated drug, obtain repeatable in vivo biodistributions to different organs and tissues, and obtain the maximum protection of (protein) drugs from degradation. This review classifies monodisperse polymer MS according to their methods of production and gives examples of the formation of uniform MS and their applications in the medical field. In the literature, the term 'monodisperse' is often used inaccurately, and this article attempts to rectify this by clearly defining monodispersity in terms of the coefficient of variation and the polydispersity index, the two statistical quantities most frequently used to describe the size distribution of MS.

Lung perfusion imaging with monosized biodegradable microspheres.

After intravenous injection, particles larger than red blood cells will be trapped in the first capillary bed that they encounter. This is the principle of lung perfusion imaging in nuclear medicine, where macroaggregated albumin (MAA) is radiolabeled with (99m)Tc, infused into a patient's arm vein, and then imaged with gamma scintigraphy. Our aim was to evaluate if monosized microspheres could replace (99m)Tc-MAA. Biodegradable poly(L-lactide) microspheres containing chelating bis(picolylamine) end groups were prepared by a flow focusing method on a microfluidic glass chip and were of highly homogeneous size (9.0 +/- 0.4 microm). The microspheres were radiolabeled with [(99m)Tc(H(2)O)(3)(CO)(3)](+) and then evaluated in mice for lung perfusion imaging. Fifteen minutes after injection, 79.6 +/- 3.8% of the injected activity was trapped in the lungs of mice. Monosized biodegradable radioactive microspheres are, thus, appropriate lung perfusion imaging agents. Other sizes of these highly uniform microspheres have the potential to improve diagnostic and therapeutic approaches in diverse areas of medicine.