Secondary Echinococcus multilocularis infection in A/J mice: delayed metacestode development is associated with Th1 cytokine production

The course of Echinococcus multilocularis infection was studied in four different strains of mice after intrahepatic inoculation of a metacestode homogenate. Among these strains of mice, A/J and BALB/c mice were characterized, respectively, as the most resistant and susceptible strains. Although there was no significant difference between the mean surface of hepatic metacestodes of these two strains of mice at any examination time, 13 weeks after infection, the mean metastatic burden of A/J mice was significantly lower than that of BALB/c mice. Moreover, at this time, some BALB/c mice spontaneously died from their infection whereas all A/J mice remained in good health .
The relative resistance of A/J mice to parasite development was associated with a strong and sustained in vitro spleen cell proliferative response to a crude E. multilocularis extract as well as with a high parasite-induced production of IFN-γ and IL-2. The susceptibility of BALB/c mice was on the contrary associated with a high IL-4 production. Interestingly, the parasite extract also stimulated a significant IL-4 production by spleen cells of uninfected susceptible BALB/c mice, but not by control A/J mouse spleen cells. Altogether, these results suggest that the relative resistance of A/J mice to E. multilocularis growth is associated with the development of T cell responses characterized by the production of high levels of Th1 cytokines .     

Synthesis of a biotinylated,iodinatable, and photoactivatable probe for angiotensin receptors

We propose here a biotinyl-aminohexanoyl-[Ala¹, Phe(4N₃)⁸]angiotensin II analog as a radioiodinatable and photoactivatable probe for covalent labeling, detection and isolation of angiotensin receptors. A combination of solid phase and minimum-protection segment-coupling strategy using hexafluorophosphate of (benzotriazol-l-yloxy)tris(dimethylamino)phosphonium (BOP) as a coupling reagent is proposed for the synthesis of this probe. Optimized yields were obtained by HPLC monitoring of all reactions. A complete n.m.r. study suggests an extended conformation of this molecule, allowing a simultaneous recognition of receptor and avidin. The probe binds with high affinity (K_d= 2 nM) to angiotensin II receptors from rat liver membranes.     

A Method for Permanent Transvenous Left Ventricular Pacing

LV-based pacing has recently been reported to be of benefit in patients with severe cardiac failure and left bundle branch block. LV permanent pacing has been reported using epicardial leads but the surgical mortality is excessive. A transvenous approach is now favored. In this regard, cannulation of the coronary sinus and of one of its tributaries using only the permanent electrode is feasible but technically challenging. We describe a "long guiding sheath" method using catheterization, and a long radiopaque and peelable sheath. Once the coronaiy sinus is cannulated with the electrophysiological catheter, the long sheath is advanced to the mid-part of the coronary sinus. The permanent pacing electrode is then placed through the sheath and into a tributary of the coronary sinus. This method has been attempted in 10 patients and was successful in 8, with an average lead insertion time of 21 ± 5.5 minutes and an average fluoroscopic time of 11 ± 5.5 minutes. In conclusion, although transvenous left ventricular pacing remains a challenge, the "long guiding sheath" approach appears to facilitate this procedure with both a high success rate and an acceptable procedure time.     

Is adenoidectomy in children safer with laryngeal mask airway or with tracheal intubation?

Adenoidectomy in paediatric outpatient surgery is assumed to require tracheal intubation (TT). The laryngeal mask airway (LMA) commonly used for general paediatric surgery has never been previously studied for adenoidectomy. We therefore prospectively compared in a randomized manner, the incidence of complications with TT and LMA in 56 children undergoing adenoidectomy. Preoperative, intraoperative and the lowest SPO₂ values after removal of either TT or LMA were recorded. The respiratory complications, cough, stridor and/or laryngospasm, were recorded intraoperatively and after removal of the airway device. The oxygen saturation levels were significantly higher in the laryngeal mask airway group both intraoperatively and after removal of the respiratory device (P<0.05). The incidence of respiratory complications was lower in the LMA group. In conclusion we have shown that the laryngeal mask airway with a flexometallic tube is a satisfactory alternative to tracheal intubation for outpatient paediatric adenoidectomy.     

Androgen receptor in human skin

Cytosol androgen receptor was assayed in 18 human skin biopsies by an exchange technique with a labelled potent synthetic androgen, methyltrienolone (R 1881), under conditions which measured total (i.e. both free and occupied) binding sites. Androgen binding sites were only present in skin biopsies from patients with marked seborrhoea often accompanied by acne (8 cases) and no sites were detected in normal skin biopsies (7 cases). Three biopsies from seborrhoeic patients, however, did not contain androgen receptor. Although no direct quantitative correlation could be drawn between binding site concentration and sebum excretion, it would seem that the androgen receptor content nevertheless constitutes an important parameter in the study of the hormonal control of seborrhoea.     

The gp 130 family cytokines IL-6, LIF and OSM but not IL-11 can reverse the anti-proliferative effect of dexamethasone on human myeloma cells

Summary. In order to understand the mechanisms supporting steroid escape in patients with multiple myeloma (MM), three IL-6 autocrine human myeloma cell lines, LP1, OPM2 and L363, have been treated with dexamethasone in the presence or absence of cytokines belonging to the gp 130 family: IL-6, LIF, OSM and IL-11. With pharmacological doses of dexamethasone, a dramatic growth arrest was observed in all the cell lines. IL-6 completely reversed this inhibition. Of note, this IL-6 induced reversion was still seen with very low amounts of IL-6 (12 pg/ml). Finally, whereas LIF and OSM had clear growth-promoting effects on OPM2 only, both cytokines (but not IL-11) reversed the dexa-methasone-induced growth arrest in all the cell lines. Therefore the high levels of IL-6 (ng/ml) observed in the MM intermediate milieu and the putative presence of LIF and OSM can easily counteract the effects of dexamethasone in vivo.     

Transcutaneous T Wave Shock: A Universal Method for Ventricular Fibrillation Induction

Our objective was to develop a universal noninvasive method for VF induction. ICD implantation requires VF induction. Conventional rapid ventricular stimulation may fail to induce VF. Some ICDs can deliver low energy shocks on the T wave to induce VF. We hypothesized that an external dual chamber pacemaker and an external defibrillator could be configured to allow reliable VF induction with any ICD system. A surface ECC signal was delivered to the atrial channel of an external dual chamber DDD pacemaker. The 'AV' delay was adjusted so that the ventricular output of the pacemaker was delivered to an external defibrillator synchronized to deliver 5–50 J. Twenty-six patients at ICD implant or follow-up had VF induced in native rhythm (sinus rhythm or atrial fibrillation), or during a ventricular pacing train (3–8 beats at cycle length 500–880 ms). VF was successfully induced in 14 of 25 (56%) patients in native rhythm; and in 16 of 17 (94%) patients during pacing (P = 0.013). VF induction success rate was 36% in native rhythm (31/86 attempts) and 88% during pacing (69/78 attempts) (P < 0.001). The 'R' to shock interval was 269 ± 31 ms in native rhythm and 257 ± 48 ms during pacing. Energy delivered from the external defibrillator was 19 ± 3 J in native rhythm and 21 ± 6 J during pacing. We concluded that VF induction by synchronizing a small external shock to the T wave is a fast, effective way to reliably ensure arrhythmia induction with any ICD at implant or follow-up. This method is more successful during pacing than in sinus rhythm.