Cricoid pressure impedes placement of the laryngeal mask airway and subsequent tracheal intubation through the mask

We have studied 40 patients to see if cricoid pressure affectsthe success rate of ventilation through, and the position of,the laryngeal mask and subsequent fibrescope-aided trachealintubation. Adequate ventilation of the lungs was produced throughthe laryngeal mask in 19 of 20 patients in the control group,but in only 10 of 20 patients in the cricoid pressure group(P < 0.002). The laryngeal mask was positioned correctlyin 16 patients in the control group, but in only two patientsin the cricoid pressure group (P < 0.001). Tracheal intubationwas accomplished in 19 patients in the control group, but inonly three patients in the cricoid pressure group (P < 0.001).Release of cricoid pressure after placement of the laryngealmask improved the view of the glottis, but tracheal intubationwas still difficult because of laryngeal deviation. These resultsshow that cricoid pressure impedes placement of the laryngealmask and subsequent fibrescope-aided tracheal intubation. (Br.J. Anaesth. 1994; 72: 47–51)      

Neurological Manifestations Associated with Cold Hemagglutinin Syndrome Report of Two Cases

Two cases of cold hemagglutinin syndrome associated with neurological manifestations were reported. One was a 52-year-old woman with acute hemolytic anemia which developed following grippe. Cold hemagglutinin titer was elevated to 1:1,024. Neurological manifestations were apathy, confusion, auditory hallucination and EEG abnormality. Steroid administration cleared these neurological abnormalities and EEG was reverted to normal. The other was a 77-year-old man with chronic hemolytic anemia. Cold hemagglutinin titer was extraordinarily elevated (1:32,768, 1:524,-288). Neurological abnormalities were almost confined to the cerebellar system. Hormonal therapy was completely unrewarding and the patient was incapacitated from his daily activity. From the literature some of the reported cases of hemolytic anemia associated with neurological abnormalities, particularly in reference to cold hemagglutinin syndrome, were briefly described. The present authors consider 2 reported cases fall in the category of “Syndromes neuro-hémolytiques” by French school.     

Cricoid pressure impedes placement of the laryngeal mask airway

We have studied 22 patients to examine whether or not cricoidpressure affects ventilation of the lungs via the laryngealmask and its correct positioning. In a randomized, crossoverdesign, the laryngeal mask was inserted with or without cricoidpressure applied with a standardized force of 30 N using a cricoidyoke. A standardized pillow (6 cm in height) was placed underthe patient occiput, but the neck was not supported. Ventilationof the lungs via the laryngeal mask was adequate in all patientswhen no cricoid pressurewas applied, but in only three of 22patients when cricoid pressure was applied (P <<0.001; 95% confidence interval (Cl) 0.72–1.0). The mask waspositioned correctly in 18 patients when no pressure was applied,and in none after application of cricoid pressure (P <<0.001; 95% Cl 0.66–0.98). We had planned to study, inan additional 20 patients, the effect of cricoid pressure withouta pillow under the occiput; placement of the mask, however,was difficult even when cricoid pressure was not applied andthere was a high incidence of bleeding from the oropharynx.We thus abandoned that part of the study after eight patients.In those eight patients, the success rate of ventilation viathe laryngeal mask was lower when cricoid pressure was applied.We conclude that when sufficient force was applied, cricoidpressure, regardless of the method of application, did impedeplacement of the laryngeal mask. (Br. J. Anaesth. 1995; 74:521–525)     

Reduction of the DTH response is related to morphological changes of Langerhans cells in mice exposed to acute immobilization stress

There is a large body of evidence indicating that stress influences immune competence. For example, psoriasis and atopic dermatitis may be exacerbated by psychic stress and related to abnormalities in the cellular constituents of the immune system in the skin. However, the underlying mechanisms remain unclear. We therefore investigated the potential of acute immobilization stress to affect the DTH response in BALB/c mice. DTH was significantly reduced in an immobilization time-dependent manner when stress exposure was just before sensitization. Although the number of Langerhans cells (LC) did not change under these conditions, marked alteration of LC morphology was observed with a significant decrease in area. Recovery of LC was observed within 24 h when the DTH response was also restored. Expression of the calcitonin gene-related peptide (CGRP), which inhibits LC antigen presentation, was significantly increased up to 1.6-fold in nerve fibres of immobilized mice. We conclude that stress-induced suppression of DTH could be due to reduction of LC antigen presentation with morphological change in association with CGRP elevation.     

Hyperbaric oxygen stimulates cell proliferation and normalizes multidrug resistance protein-2 protein localization in primary rat hepatocytes

Hyperbaric oxygen therapy (HBO) has been used for many clinical treatments, including primary liver non-function. However, the cellular mechanism by which HBO treatment ameliorates liver function is not understood. Therefore, the purpose of this study was to elucidate this cellular mechanism using primary cultured rat hepatocytes in in vitro studies. Hepatocytes were treated with HBO at 1 day after plating, and the morphological and functional characteristics of bile canaliculi formed in cultured hepatocytes were observed by time-lapse microscopy. Multidrug resistance protein-2 localization was observed by confocal laser microscopy. In cultured hepatocytes, the labeling index in the HBO group at 2 days after treatment was significantly higher than that in the control group. In addition, the proliferating cellular nuclear antigen level in the HBO group was significantly higher than that in the control group. The contraction of the bile canaliculi in the HBO group was slower than in the control group and the dilatation of bile canaliculi in the HBO group was much larger than in the control group. Multidrug resistance protein-2 in the HBO group was localized at the apical membrane. These results show that HBO stimulates hepatocytes to proliferate and HBO normalizes multidrug resistance protein-2 localization to the apical membrane, which could dilate bile canaliculi.     

Interaction of the active metabolite of prasugrel,R‐138727, with cysteine 97 and cysteine 175 of the human P2Y12 receptor

Summary. Background: The P2Y₁₂ receptor plays a crucial role in platelet aggregation and is the target of platelet aggregation inhibitors, including the thienopyridine compound prasugrel. Objective: The present study analyzed the effects of R‐138727 (2‐[1‐[2‐cyclopropyl‐1‐(2‐fluorophenyl)‐2‐oxoethyl]‐4‐mercapto‐3‐piperidinylidene]acetic acid), the active metabolite of prasugrel, on recombinant wild‐type and mutant human P2Y₁₂ receptors in order to identify the molecular site of action of R‐138727. Methods: The function of wild‐type and mutant P2Y₁₂ receptors stably expressed in Chinese hamster ovary cells was assessed by measuring the 2‐methylthio‐ADP‐mediated inhibition of forskolin‐stimulated cellular cAMP production. Results: In cells expressing wild‐type receptors, R‐138727 potently inhibited receptor function with a half‐maximal concentration below 1 μm . The mode of action was irreversible. The same effect of R‐138727 was observed in cells expressing Cys17Ala/Cys270Ala constructs. In contrast, in cells expressing either a Cys97Ala construct or a Cys175Ala construct, R‐138727 failed to inhibit the response to the agonist. When cells expressing wild‐type receptors were pretreated with the P2 receptor antagonists ATP or suramin, no effect of R‐138727 was observed. Similar experiments with N‐acetylcysteine 10 μm showed no interference of N‐acetylcysteine with R‐138727. Conclusions: The experiments demonstrate a potent and irreversible action of R‐138727 at the recombinant human P2Y₁₂ receptor. The data suggest that R‐138727 interacts with cysteine 97 (upper portion of the predicted third transmembrane region) and cysteine 175 (second extracellular loop) of the receptor, which are likely to form a disulfide bridge in native receptors. Moreover, the data also suggest that this site of action of R‐138727 is close to the ligand‐binding site of the receptor.