Anesthesia residents' preference for learning interscalene brachial plexus block (ISBPB): traditional Winnie's technique vs. ultrasound-guided technique.

There is a recent shift from traditional nerve stimulation (NS) to ultrasound-guided (UG) techniques in regional anesthesia (RA). This shift prompted educators to readdress the best way to teach these two modalities. Development of a more structured curriculum requires an understanding of student preferences and perceptions. To help in structuring the teaching curriculum of RA, we examined residents' preferences to the methods of instruction (NS Vs. UG techniques). Novice residents (n=12) were enrolled in this parallel crossover trial. Two groups of 6 residents received a didactic lecture on NS or UG techniques. The groups then crossed over to view the other lecture. After they observed a demo of ISBPB on two patients using NS and US. The residents completed a questionnaire regarding their impression of each technique and the learning experience. UG technique was perceived to be safer and to have more educational value than NS. However, residents felt both techniques should be mandatory in the teaching curriculum.

Challenges to a blow/fill/seal process with airborne microorganisms having different resistances to dry heat.

Controlled challenges with air dispersed microorganisms having widely different resistances to dry heat, carried out on 624 BFS machine processing growth medium, have shown that higher the heat resistance, the greater the extent of vial contamination. Differences in heat resistance affected also the extent of vial contamination when parison and vial formation were knowingly manipulated through changes made to each of three process variables, provision of ballooning air, mould vacuum delay, and parison extrusion rate. The findings demonstrate that, in this investigational system, exposure of challenge micoorganisms to heat inherent in the process has a controlling influence on vial contamination, an influence that could also control microbiological risk in production environments.

Impact of Blow/Fill/Seal process variables in determining rate of vial contamination by air dispersed microorganisms.

Controlled challenges of air dispersed spores of Bacillus subtilis NCIMB 8649 have been generated in a custom-built challenge room housing a Blow/Fill/Seal machine filling filter-sterilized trypticase soy broth into 5.5 cm3 low density polyethylene vials. The effects on the rate of vial contamination of systematic changes in the process variables, rate of provision of ballooning air, delay in the application of mould vacuum and duration of transfer of the open vial, have been examined. Overall, the findings show that the conditions of vial formation can affect appreciably the rate of vial contamination from airborne spores. The indications are that heat lethality, associated with the elevated temperature required for polymer extrusion and vial formation, has a role in determining such contamination.

Inherent desensitisation-preventing properties of a novel, subtype-selective AMPA receptor agonist, (S)-CPW 399, as a possible explanation for its excitotoxic action in cultured cerebellar granule cells.

The synthesis and pharmacological characterisation of (S)-CPW 399 as a novel, potent and subtype-selective agonist of the AMPA receptor was recently reported. Studies have been extended to investigate its excitotoxic action in primary cultures of mouse cerebellar granule cells. (S)-CPW 399 induced neuronal cell death in a time- and concentration-dependent manner (EC(50) approximately 70 microM) at 24-h exposure. (S)-CPW-induced neuronal death could be prevented by co-administration with either of the AMPA/kainate selective receptor antagonists 6-cyano-7-nitro-quinoxaline-2,3-dione (CNQX) and 6-nitro-7-sulphamoylbenzo[f]quinoxaline-2,3-dione (NBQX) or by the 2,3-benzodiazepine, GYKI 53655 (a selective AMPA receptor antagonist); while no protection was afforded by either the NMDA receptor antagonist D,L(+/-)-2-amino-5-phosphonopentanoate (APV) or by nifedipine (an L-type calcium channel antagonist) when used alone or in combination. Cyclothiazide, which blocks AMPA receptor desensitisation, caused minimal potentiation of (S)-CPW 399-induced neuronal death, supporting accumulating evidence that (S)-CPW 399 is a full AMPA receptor agonist that markedly prevents a receptor desensitised conformation. (S)-AMPA, (S)-willardiine (a naturally-occurring heterocyclic excitatory amino acid) and its halogenated derivative, (S)-5-fluorowillardiine, had no deleterious effect on neuronal viability when used alone but each, in the presence of cyclothiazide, induced a concentration-dependent excitotoxic cell death with a rank order of potency (fluorowillardiine>>AMPA=willardiine). (S)-CPW 399 stimulated an increase in intracellular free-calcium levels ([Ca(2+)](i)) in a concentration-dependent fashion (EC(50) approximately 5 microM) attaining a value of six-fold that of 'resting' cells at maximum stimulation; achieved at approximately 100 microM (S)-CPW 399. The (S)-CPW 399-stimulated increase in [Ca(2+)](i) was virtually abolished by GYKI 53655, NBQX, CNQX and by cobalt ions; markedly inhibited by nifedipine and marginally affected by D-APV. These results suggest that (S)-CPW 399 may be used as a pharmacological tool to aid in the investigation of the role of AMPA receptors in excitotoxicity and their molecular mechanisms of desensitisation.

Heartport endoclamp for complex cardiac repairs with total circulatory arrest.

A method of performing redo cardiac operations using port-access technology and total circulatory arrest is described. The technique was useful in 2 cases requiring re-intervention within 4 months of the primary procedure. The indications were repair of an infected ventricular aneurysm and recurrence of a postinfarction ventricular septal defect. Dense mediastinal adhesions were avoided by approaching the site of pathology directly via a left anterior thoracotomy.

Definition of a correlation between microbiological and physical particulate barrier performances for porous medical packaging materials.

An experimental set up, assembled principally from components of commercially available filter test equipment, has allowed assessment of physical particulate barrier performance of porous materials. Employing twelve specially made papers with graded and widely different barrier properties, a physical particulate/microbiological correlation has been derived covering the 50,000 fold range of microbiological barrier performances seen in commercial porous medical packaging materials. The derived correlation has been shown to be independent of sheet structure and is applicable to the diverse structures that comprise commercial materials. A simple measurement of particle penetration is proposed as a means of assessing microbial barrier properties of such materials.

Air Sampling System for use in monitoring viable and non-viable particulate air quality under dynamic operating conditions of blow/fill/seal processing.

An Air Sampling Link (ASL), employed in conjunction with an Air Sampling Device (ASD) or a laser particle counter, has been developed for sampling flowing air for viable and non-viable particulate analyses. Typically, the ASL could be used to sample filtered air supplied to an air shower of a Blow/Fill/Seal machine operating in the dynamic state. The ASL allows sample volumes of air to be taken from flowing air without significant loss from the sample flow of airborne particles possessing aerodynamic sizes relevant to those found in practice. The link has no moving parts, is steam sterilizable in-situ, and allows for the taking of continuous samples of air without the need for intervention into the 'critical zone' of the filling machine. This article describes (i) the design criteria for the ASL and the ASD, (ii) the rationale underlying the concept of the ASL design, (iii) the collection performance of the ASL against that of a conventional sampling arrangement, and (iv) a functionality assessment of the ASL-based sampling system installed on a Rommelag style 305 B/F/S machine over a seven week period.

Evaluation of Blow/Fill/Seal extrusion through processing polymer contaminated with bacterial spores and endotoxin.

A study has been carried out to further the understanding of the extrusion process and its impact upon the quality of Blow/Fill/Seal product. Controlled challenges to the extrusion system, comprising low-density polyethylene granulate contaminated with characterized levels of Bacillus atrophaeus (ATCC 9372) endospores and Escherichia coli 055:B5 bacterial endotoxin, have been conducted. Batches of spore contaminated polymer, at challenge levels varying from 10(3) to 10(6) spores g(-1) polymer with derived D160 values ranging from 1.22 to 2.07 minutes, and endotoxin contaminated polymer, at challenge levels varying from 10(2) to 10(4) EU g(-1) polymer, were processed through a Blow/Fill/Seal machine employing Tryptone Soya Broth and Water for Injection as the fill mediums, respectively. Relationships have been established between the levels of challenge for each of spores and endotoxin and the extent of product contamination. The relationships allow for prediction of microbiological and pyrogenic quality based upon the microbiological and pyrogenic attributes of unprocessed polymeric granulate and for rationalized choices of polymeric granulate acceptance limits. It is stressed that the findings apply only to the particular Blow/Fill/Seal machine and to the specific conditions of machine operation.

Absence of aquaporin-4 expression in lesions of neuromyelitis optica but increased expression in multiple sclerosis lesions and normal-appearing white matter.

Aquaporin-4 (AQP4) has recently been implicated in the pathogenesis of neuromyelitis optica (NMO) where it has been identified as the first defined autoantigen pertinent to an inflammatory demyelinating disorder of the human CNS. Furthermore, a recent case report has shown a lack of AQP4 expression in the spinal cord lesions of NMO. However, the pattern of AQP4 expression in multiple sclerosis (MS) tissues has not been well-defined. In the present investigation we have confirmed a lack of expression of AQP4 in optic and spinal cord lesions in NMO which contrasted sharply with the increased levels of AQP4 expression seen in MS lesions. Furthermore a detailed immunohistochemical and semi-quantitative analysis is used to describe the expression pattern of AQP4 on well-characterized tissue microarray samples of MS and control white matter. Anatomically AQP4 was more highly expressed in all categories of MS tissue compared to normal control tissues with the most abundant expression in active lesions. Within active lesions AQP4 expression was significantly correlated with expression of the pro-inflammatory cytokine osteopontin. At the cellular level dual-labeling immunofluoresence demonstrated that increased expression of AQP4 was most pronounced at the astrocytic endfeet but was also associated with the cell bodies of astrocytes in the tissue parenchyma. The finding of increased AQP4 expression in MS lesions in contrast to the lack of expression in NMO lesions may suggest different mechanisms of initiation and progression between the two disease states.

Optimal myocardial protection strategy for coronary artery bypass grafting without cardioplegia: prospective randomised trial.

Although hypothermia and ischaemic preconditioning (IP) are independently recognised mechanisms of cardioprotection, interactions between myocardial temperature and preconditioning have not been investigated. Therefore, this study explored the possibility of inducing IP during hypothermia and quantifying its effects at two temperature regimens commonly used in clinical practice. One hundred and four patients undergoing coronary artery bypass grafting (CABG) with intermittent cross-clamping and ventricular fibrillation were randomised to four groups: N=normothermia (36.5+/-0.5 degrees C); NP=normothermia+preconditioning, H=hypothermia (31.5+/-0.5 degrees C), HP=hypothermia+preconditioning. The primary outcome measure was release of cardiac Troponin I (cTnI), measured at 6 time points from pre- to 72 h after the end of CPB. There were no hospital deaths and no significant differences in pre- and intra-operative variables (P>or=0.05). There were significant differences in cTnI release between all groups, as follows: N: 117+/-12 microg/l (P