Detecting dipolarity of the geomagnetic field in the paleomagnetic record.

Recovering the geomagnetic field strength in the past is key to understanding deep Earth dynamics and detecting potential geodynamo regimes throughout the history of Earth. To better constrain the predictive power of the paleomagnetic record, we propose an approach based on the analysis of the dependency between geomagnetic field strength and inclination (angle made by the horizontal with the field lines). Based on the outcomes of statistical field models, we show that these two quantities should correlate for a wide range of Earth-like magnetic fields, even with enhanced secular variation, persistent nonzonal components, and severe noise contamination.

Developing a new simplified method to determine diffusive uptake rates of volatile organic compounds in workplaces based on a fractional factorial designs approach.

Exposure to organic vapors in the workplace is a source of occupational risk. Admissible exposure levels are tightly regulated and must be closely monitored. However, the complexity and slowness of the existing complete protocols to determine diffusive uptake rates through passive sampling have limited the use of this tool despite obvious advantages.

Time course of liver nitric oxide concentration in early septic shock by cecal ligation and puncture in rats.

An overwhelming nitric oxide (NO) production is a crucial step in the circulatory events as well as in the cellular alterations taking place in septic shock. However, evidences of this role arise from studies assessing the NO production on an intermittent basis precluding any clear evaluation of temporal relationship between NO production and circulatory alterations. We evaluated this relationship by using a NO specific electrode allowing a continuous measurement of NO production.

Quantitative measurement of propofol and in main glucuroconjugate metabolites in human plasma using solid phase extraction-liquid chromatography-tandem mass spectrometry.

A high-performance liquid chromatographic method coupled with tandem mass spectrometry detection has been developed for the determination of propofol and its main glucuroconjugate metabolites (propofol-glucuronide (PG), 1-quinol-glucuronide (1-QG) and 4-quinol-glucuronide (4-QG) in human plasma. All compounds were extracted with a single solid phase extraction procedure using Max Oasis cartridges. Propofol and thymol (internal standard) were analyzed using a C8 reversed-phase column with a mobile phase consisting of methanol-water (75:25, v/v) containing 0.

Increased intra-abdominal pressure affects respiratory variations in arterial pressure in normovolaemic and hypovolaemic mechanically ventilated healthy pigs.

Objective: To evaluate the effect of increased intra-abdominal pressure (IAP) on the systolic and pulse pressure variations induced by positive pressure ventilation in a porcine model.

Design And Setting: Experimental study in a research laboratory.

Subjects: Seven mechanically ventilated and instrumented pigs prone to normovolaemia and hypovolaemia by blood withdrawal.

Behavior of the GABIE, 3M 3500, PerkinElmer Tenax TA, and RADIELLO 145 diffusive samplers exposed over a long time to a low concentration of VOCs.

Diffusive sampling is particularly suited to determine time-weighted average volatile organic compound (VOC) concentration in occupational hygiene and environmental air monitoring. The purpose of this study was to measure the sampling rate variation of four different samplers in a special use--the exposure to a low concentration of volatile organic compound (10 to 200 ppb) for a long period (1 to 14 days). PerkinElmer tube-type adsorbent was packed with Tenax TA and RADIELLO cartridge packed with Carbograph 4.

[Amniotic fluid embolism: successful evolution course of isolated disseminated intravascular coagulation and early biological diagnosis].

Amniotic embolism is a sudden, unexpected and devastating complication of pregnancy. The diagnosis is usually made on the basis of clinical presentation after excluding differential diagnosis or at autopsy in the event of death of the parturient. We need to develop simple, non-invasive, sensitive tests for a reliable and early diagnosis.

Nitric oxide and liver microcirculation during autoregulation and haemorrhagic shock in rabbit model.

Background: Direct evidence of nitric oxide (NO) involvement in the regulation of hepatic microcirculation is not yet available under physiological conditions nor in haemorrhagic shock.

Methods: A laser Doppler flowmetry was used to measure liver perfusion index and a specific NO-sensitive electrode was inserted into liver parenchyma of anaesthetized rabbits. Hepatic autoregulation during moderate hypovolaemia {mean arterial pressure at 50 mm Hg without liver perfusion alteration; blood withdrawal 17.

Effects of increased intra-abdominal pressure on central circulation.

Background: In an experimental model we investigated the effects of a gradual increase in intra-abdominal pressure (IAP) on the central circulation.

Methods: Seven pigs were anaesthetized, mechanically ventilated and instrumented. IAP was gradually increased by 5 mm Hg up to 30 mm Hg by abdominal banding in normovolaemic animals, and then they were made hypovolaemic after blood withdrawal.

Uncoupling the systemic circulation and the Ex Vivo circuit during experimental isolated liver perfusion.

Performing an ex vivo liver perfusion as a transient liver support requires perfusing the liver with a flow of 1 ml/min per kg of liver, which could reach 25% of the cardiac output when a human liver is used. This high flow could be detrimental in patients with acute liver failure. Therefore, in an ischemic-induced liver failure pig model, we developed a circuit allowing low flows going out of and into the systemic circulation, whereas the flow going through the ex vivo liver is maintained at a high value.

Spontaneous baroreflex cardiac sensitivity in end-stage liver disease: effect of liver transplantation.

Background And Objective: End-stage liver disease is associated with an imbalance in the autonomic nervous system. The purpose of this study was to estimate the effect of liver transplantation on this imbalance.

Method: The study involved 10 patients undergoing liver transplantation and 9 patients without liver impairment undergoing liver surgery.

The role of hepatic type 1 plasminogen activator inhibitor (PAI-1) during murine hemorrhagic shock.

Hemorrhagic shock (HS) followed by resuscitation (HS-R) is characterized by profound physiological changes. Even if the patient survives the initial blood loss, these poorly understood changes can lead to morbidity. One of the tissues most often affected is liver.

Liver function during extracorporeal whole liver perfusion in a pig model of acute ischemic liver failure.

The shortage of livers for transplant has renewed interest in the potential of temporary liver support such as extra corporeal whole liver perfusion. In an ischemic induced liver failure model we perfused an extra corporeal liver through only a portal vein and assessed the function of this ex vivo liver by using hepatic tests to estimate elimination as well as synthesis capacities. Acute liver failure was performed in five control pigs by a hepatic devascularization associated to an end to side portocaval shunt.

Hepatic ischemia is associated with an increase in liver parenchyma nitric oxide that is in part enzyme-independent.

Background: Nitric oxide (NO) might be involved in liver response to local ischemia-reperfusion injury.

Methods: A specific NO-sensitive electrode was inserted into liver parenchyma of anesthetized rabbits. After a 45-min period of stable NO signal, the vascular pedicle of the caudal lobe of the liver was clamped for 45 min, then the clamp was removed.

Pharmacological preconditioning: comparison of desflurane, sevoflurane, isoflurane and halothane in rabbit myocardium.

Background: Recent investigations showed that isoflurane can induce pharmacological preconditioning. The present study aimed to compare the potency of four different halogenated anaesthetics to induce preconditioning.

Methods: Anaesthetized open-chest rabbits underwent 30 min of coronary artery occlusion followed by 3 h of reperfusion.

[The carpus-metacarpus-index distance: a measurement for quantifying radiological lesions in rheumatoid polyarthritis. Comparison with Larsen's scores and Steinbrocker's index].

The carpus-to-digits distance measured on a posteroanterior roentgenogram of the hands and wrists takes into account 18 different joints. This study demonstrates that the carpus-to-digit distance is a simple, reproducible score which reliably reflects progression of roentgenological rheumatoid arthritis lesions and is correlated with Larsen's lesion score and with Steinbrocker's index, but not with Larsen's erosion score during the first two years after onset of the disease. Larsen's erosion score and similar parameters should be preferred for clinical studies of recent-onset rheumatoid arthritis.

[MRI of the knee. Value of delayed sequences after intravenous injection of gadolinium].

A prospective study of delayed sequences after intravenous injection of gadolinium for knee MRI shows the similar results as from the literature: enhancement of synovial fluid after 30 minutes. Sixteen patients were studied mainly with gradient echo. This phenomenon improves the visualisation of the intraarticular structures like meniscus, cruciate ligaments, or cartilage.

[Chemolysis of intravertebral disk hernia and spinal syndrome].

The authors report a 31 year old patient who underwent L5-S1 chemonucleolysis. The prenucleolysis discogram disclosed intravertebral discal displacement. Severe spinal symptoms and development of geodes in the endplates adjacent to the treated disk occurred after the procedure.

Magnetic resonance imaging of acoustic neuromas: pitfalls and differential diagnosis.

A total of 162 patients with suspected acoustic neuromas underwent MR imaging at 1.5 T. All patients were injected with Gd DTPA or DOTA.

[Radiologic anatomy of the wrist].

Wrist imaging still relies first on plain X-Ray films, MRI allows excellent appreciation of the sculture of bones, ligaments, tendons and even nerves. C.T.