A tetra-primer amplification refractory mutation system polymerase chain reaction for the evaluation of rs12979860 IL28B genotype.

Recently, genome-wide association studies in patients affected by HCV infection have identified a strong association between sustained virological response to peg-interferon/ribavirin and spontaneous viral clearance and common single nucleotide polymorphisms (SNPs) near the IL28B gene, encoding for interferon-lambda-3. Thus, it is anticipated that IL28B genotype determination will be integrated in clinical practice to guide treatment decisions. Here, we describe a simple tetra-primer amplification refractory mutation system polymerase chain reaction (T-ARMS-PCR) for the evaluation of the rs12979860 C>T IL28B SNP, for which strong evidence of association with clinical outcomes has been collected in subjects of European descent. Valid genotypic data were obtained for over 99% of subjects analysed, and T-ARMS-PCR procedures were validated by the analysis of DNA samples of 164 patients with chronic HCV infection. In conclusion, this method allows rapid, reproducible, inexpensive and accurate detection of rs12979860 polymorphism without need of any special equipment and is also suitable for evaluation of a low number of samples on a routine basis.

Cholesterol depletion activates rapid internalization of submicron-sized acetylcholine receptor domains at the cell membrane.

Novel effects of cholesterol (Chol) on nicotinic acetylcholine receptor (AChR) cell-surface stability, internalization and function are reported. AChRs are shown to occur in the form of submicron-sized (240-280 nm) domains that remain stable at the cell-surface membrane of CHO-K1/A5 cells over a period of hours. Acute (30 min, 37 degrees C) exposure to methyl-beta-cyclodextrin (CDx), commonly used as a diagnostic tool of endocytic mechanisms, is shown here to enhance AChR internalization kinetics in the receptor-expressing clonal cell line. This treatment drastically reduced ( approximately 50%) the number of receptor domains by accelerating the rate of endocytosis (t(1/2) decreased from 1.5-0.5 h). In addition, Chol depletion produced ion channel gain-of-function of the remaining cell-surface AChR, whereas Chol enrichment had the opposite effect. Fluorescence measurements under conditions of direct excitation of the probe Laurdan and of Förster-type resonance energy transfer (FRET) using the intrinsic protein fluorescence as donor both indicated an increase in membrane fluidity in the bulk membrane and in the immediate environment of the AChR protein upon Chol depletion. Homeostatic control of Chol content at the plasmalemma may thus modulate cell-surface organization and stability of receptor domains, and fine tune receptor channel function to temporarily compensate for acute AChR loss from the cell surface.

[The beginnings, development and decline of a technique: controlled deep arterial hypotension]. / Naissance, prospérité, déclin d'une technique: l'hypotension artérielle contrôlée profonde.

Everything started with hypovolemic hypotension (bleeding). But that was the stone age. Later, postural and drug induced normovolemic methods were used. The golden age of deliberate hypotension spanned the period from 1948 to 1980, culminating in 1975. The benefit/risk ratio was first positive, then variable and turned out to be questionable with the advent of deep hypotension, a challenge to brain hemodynamics. Progress in hemostasis surgical practices defeated deliberate hypotension. Today it is only applied in exceptional cases.

Positive end-expiratory pressure in supine and sitting positions: its effects on intrathoracic and intracranial pressures.

The effects of positive end-expiratory pressure (PEEP) on central venous and intracranial (ICP) pressures were evaluated in 10 patients with posterior fossa tumors, in both supine and sitting positions. With patients in the supine position, intrathoracic PEEP-dependent venous hypertension was clearly transmitted to the intracranial compartment but without intracranial hypertension. On the contrary, with patients in the sitting position PEEP had no influence in almost half of our patients. In patients with radiological or clinical signs of increased ICP, however, the combination of head flexion and rotation with institution of PEEP caused a dangerous increase in ICP, even when the patients were in the sitting position. The need for early withdrawal of cerebrospinal fluid in these patients is stressed.

Single donor plasma in therapeutic plasma exchange for myasthenia gravis.

Thirty-seven myasthenic patients were treated with therapeutic plasma exchange (TPE) on different performance schedules using either random or single donor plasma. The two schedules had the same effects in terms of efficacy but single donor replacement gave significantly less side effects in the short and long term. A two exchange procedure on alternate days associated with immunosuppression seems to be an optimal schedule for the treatment of myasthenic patients. A single donor two-exchange on alternate days procedure appears to be safe, useful and can be repeated in patients who need frequent TPE.

Increased activation effects of succinylcholine in neurological patients.

Succinylcholine, a depolarizing muscle relaxant with both activating and desensitizing effects, is used to facilitate endotracheal intubation. The activating effects were found to be above-normal on induction of anesthesia in 7 neurological patients: generalized muscle spasm in 1 myotonic patient, contractures or prolonged contractions in "anatomically" denervated muscles (1 patient), in "functionally" denervated muscles (1 patient) and in "centrally" denervated muscles (4 patients). One of these four presented hyperkalemia and cardiocirculatory collapse. It is important to differentiate these anomalous responses to succinylcholine from those occurring as early signs of rhabdomyolysis or malignant hyperthermia.

Phrenic nerve pacing in reversible cervical cord lesion: a case report.

Phrenic nerve pacing was performed in a patient with tetraplegia and complete respiratory insufficiency soon after cervical decompressive laminectomy for spondylotic myelopathy. The electrophrenic stimulation, in spite of being performed only unilaterally, gave respiratory autonomy to the patient, who was then no longer dependent on mechanical ventilation. This allowed him to move freely out of bed and have intensive motor rehabilitation, which in the end resulted in a satisfactory recovery. The stimulator was removed when no longer needed. The technique, the physiological parameters, and the indications for diaphragm pacing are discussed.