[Premixed 50% nitrous oxide and oxygen: theoretical recalls and practical modalities]. / Mélange équimolaire oxygène-protoxyde d'azote (MEOPA). Rappels théoriques et modalités pratiques d'utilisation.

The concept of premixed 50% nitrous oxide and oxygen dated back to 1961 in England, where it is commercialised under the name Entonox. In France, after a so marginal use, premixed 50% nitrous oxide and oxygen now knows such a revival since we first consider the pain provoked by the cure. To use correctly premixed 50% nitrous oxide and oxygen, we need to know the main properties of the nitrous oxide. The four commercial versions, now on the market, are presented (Kalinox, Medimix, Antasol, Oxynox. Except a few contraindications, these indications are large, as well at hospital as outside. In less than 10% of the cases, side effects are possible. Conditions of administration are given in details. The limits of the technic and the particular precautions of use are precised.

[MRI of the operated lumbar spine and enhancement of intradural nerve roots. 478 cases]. / IRM du rachis lombaire opéré et rehaussement des racines intradurales. 478 cas.

Authors report a study of 478 MR imaging in failed back surgery syndrome. Enhancing nerve roots were detected in 73.8%, with a significant higher percentage in male patients, and long postoperative delay. There was no significant correlation with age, enhancement of epidural scar (epidural scar was seen in 75.7%) and disk herniation (seen in 25.9%). Alteration of blood-nerve-barrier causes enhancement, but the mecanism is nuclear: mechanical, biological, immunological or Wallerian degeneration. Diagnostic and prognostic value of enhancement are not proven and a study of asymptomatic patients is necessary.

[A complication of epidural anaesthesia: the breaking of a catheter]. / Une complication de l'anesthésie péridurale: la rupture d'un cathéter.

We report the breaking of an epidural catheter, which occurred during the procedure of insertion. If such a breaking is a rare event, it is due in this case to an aberrant trajectory of the catheter. By studying the literature, we also analyzed the mechanisms which can lead to the breaking of an epidural catheter. We recommend a precise radiological examination to localise the trapped catheter among the nervous structures.

[Bacterial meningitis in HIV patient: think about co-infections!]. / Méningite bactérienne chez le patient VIH positif: pensez aux co-infections!

The authors report the case of an African 34-year-old patient who was admitted to the intensive care unit for bacterial meningitis due to Streptococcus pneumoniae. A meningeal co-infection due to Cryptococcal neoformans was found the 3rd day in an HIV infection context. Cryptococcus neoformans detection in cerebrospinal fluid, using the India-ink stain, has a low sensibility which imposes the search of cryptococcal antigen and the culture of cerebrospinal fluid. These last two exams have a sensibility of at least 90%.

[Production of circulating interferon in human malaria]. / Production d'interféron circulant au cours du paludisme humain.

The presence of an interferon-like activity inhibiting the cytopathic effect of vesicular stomatitis virus was studied in 216 sera from 100 patients with P. falciparum (67 cases), P. vivax (16), P. ovale (13), P. malariae (4) infections. 87% of patients were found positive on one or more occasions. The prevalence of interferon-like activity was similar in all 4 species. Titers varied between 20 to 320 U/ml and were found to be higher in Europeans experiencing a primary attack of malaria (mean = 72 U/ml) than in subjects from hyperendemic areas of West Africa (mean = 37 U/ml). In patients followed-up either a delayed positivity or an increase of interferon-like activity was found in 60% of cases. High titers were observed up to the 3rd month. The viral inhibitory activity met all criteria for defining interferon. Seroneutralization assays using anti-alpha and anti-gamma interferon antibodies showed in 5 patients that human malaria was associated with the presence of a gamma interferon.