A review of the EXIT (Ex utero Intrapartum Treatment) procedure.

The EXIT (Ex utero Intrapartum Treatment) procedure is done in cases where difficulty is anticipated in neonatal airway establishment at delivery and is done at the time of caesarean section. The partially delivered fetus is maintained on placental circulation while airway is established and this is carried out by a multidisciplinary team. In this paper, we review the indications, the maternal and fetal considerations of the procedure and the results and outcomes. The review highlights the fact that the benefits far outweigh the risks and that the risk of postpartum haemorrhage is more theoretical than real. As technology improves and more anomalies are diagnosed during the antenatal period, the EXIT procedure can be performed with good results after carefully considering the ethical issues. We have performed a MEDLINE search by using the keywords EXIT, CHAOS, fetal surgery, fetal neck masses and ex utero intrapartum treatment. As there are not many large studies, we have also reviewed smaller case series and case reports.

Post-cholecystectomy haemobilia: enjoying a renaissance in the laparoscopic era?

Trauma to the right hepatic artery during biliary surgery can lead to false aneurysm formation. Subsequent rupture into the biliary system, which may occur after a considerable delay, will then result in major haemobilia. This report details five cases referred to the Royal Melbourne Hospital over a 12 month period, four of which followed initial laparoscopic procedures, and emphasizes important management procedures to prevent and treat this previously rare complication.

Energy metabolism during damaging contractile activity in isolated skeletal muscle: a 31P-NMR study.

Creatine kinase (CK) release in response to excessive electrically stimulated contractile activity has been studied in isolated rat soleus muscles. The exacerbation of CK release induced by contractile activity was found to be directly related to the length of time for which the muscle was stimulated and indirectly related to the recovery of force following the end of stimulation. 31P-NMR studies were undertaken using a recirculating superfused muscle preparation and demonstrated that muscles subjected to two different stimulation protocols (stimulation for 0.5 s every 2 s in oxygenated medium or for 1.5 s every 2 s in anoxic medium) had similar falls in ATP content and pH despite a substantially greater release of CK from the muscles stimulated under anoxia. However, stimulated muscles under anoxia showed a more rapid fall and reduced recovery of phosphocreatine and a greater sustained elevation of inorganic phosphate than muscles in oxygenated medium. It is concluded that only part of the increased loss of CK from muscles stimulated in anoxic medium can be explained by release from cells which have lost energy supplies and therefore that other mechanisms must exist which allow release of CK and other cytosolic enzymes from muscle cells.

Hepatic artery pseudoaneurysms in acute pancreatitis.

The authors present a case of multiple intrahepatic pseudoaneurysms complicating acute gallstone pancreatitis, and they review the relevant literature. The complementary roles of ultrasonography, computed tomography and arteriography are illustrated. Although necrotizing vasculitis with resultant aneurysmal changes in peripancreatic vessels is a recognized complication of chronic pancreatitis, similar pseudoaneurysms have rarely been described in association with acute pancreatitis.

Molecular modelling of poly(aryl ether ketones). I. Aryl..aryl interactions in crystal structures.

Non-bonded potentials for the aryl..aryl interaction have been derived using crystal structure data of a number of small aromatic molecules. The potentials, based on atom-centered interactions, give an accurate reproduction of the benzene crystal geometry and sublimation energy when used in conjunction with coulombic energies evaluated using point atomic charges. An examination of the charge distribution on benzene suggested values of 0.13e (H) and -0.13e (C) to be suitable. The transferability of the potentials has been shown by prediction of crystal geometries and sublimation energies of other hydrocarbon molecules and, with additional interactions for the oxygen atom included, preliminary polymer crystal structure calculations have been carried out. These demonstrate the validity of the derived parameters by successfully predicting crystallographic unit cell dimensions and ring conformations in the poly(phenylene oxide) and poly(aryl ether ketone) crystals.

Energy dependence of cytosolic enzyme efflux from rat skeletal muscle.

(1) A recirculating isolated superfused skeletal muscle preparation has been developed for the study of rat soleus muscles at physiological temperature using 31P Nuclear Magnetic Resonance (NMR). (2) This system has been used to study intracellular muscle high energy phosphate content and pH during experimental damage to the muscle induced by 2,4-dinitrophenol, deoxycholate and the calcium ionophore, A23187. (3) Results indicate that release of intracellular cytosolic enzymes from damaged skeletal muscle may be induced by phosphocreatine (PCr) and adenosine trisphosphate (ATP) depletion, but under certain circumstances intracellular enzymes can be released from skeletal muscle without any fall in muscle PCr or ATP content.

The gating of nucleotide-sensitive K+ channels in insulin-secreting cells can be modulated by changes in the ratio ATP4-/ADP3- and by nonhydrolyzable derivatives of both ATP and ADP.

The 31P-NMR technique has been used to assess the intracellular ratios and concentrations of mobile ATP and ADP and the intracellular pH in an insulin-secreting cell line, RINm5F. The single-channel current-recording technique has been used to investigate the effects of changes in the concentrations of ATP and ADP on the gating of nucleotide-dependent K+ channels. Adding ATP to the membrane inside closes these channels. However, in the continued presence of ATP adding ADP invariably leads to the reactivation of ATP-inhibited K+ channels, even at ATP4-/ADP3- concentration ratios greater than 7:1. Interactions between ATP4- and ADP3- seem competitive. An increase in the concentration ratio ATP4-/ADP3- consistently evoked a decrease in the open-state probability of K+ channels; conversely, a decrease in ATP4-/ADP3- increased the frequency of K+ channel opening events. Channel gating was also influenced by changes in the absolute concentrations of ATP4- and ADP3-, at constant free concentration ratios. ADP-evoked stimulation of ATP-inhibited channels did not result from phosphorylation of the channel, as ADP-beta-S, a nonhydrolyzable analog of ADP, not only stimulated but enhanced ADP-induced activation of K+ channels, in the presence of ATP. Similarly, ADP was able to activate K+ channels in the presence of two nonhydrolyzable derivatives of ATP, AMP-PNP and beta gamma methylene ATP.

31P NMR studies on recovery from hypoxia of human tumor cells.

We describe the use of 31P NMR spectroscopy in the study of metabolic changes related to hypoxia in cultured human tumor cells in vitro. The 31P NMR spectrum can easily distinguish between metabolically active cells, metabolically inactive "dormant" cells, and necrotic cells. A crucial observation was that of the ability of the "dormant" cells to resume active metabolism on incubation with oxygen after long periods of hypoxia.