Quantitative evaluation of aerosol generation during manual facemask ventilation.

Manual facemask ventilation, a core component of elective and emergency airway management, is classified as an aerosol-generating procedure. This designation is based on one epidemiological study suggesting an association between facemask ventilation and transmission during the SARS-CoV-1 outbreak in 2003. There is no direct evidence to indicate whether facemask ventilation is a high-risk procedure for aerosol generation. We conducted aerosol monitoring during routine facemask ventilation and facemask ventilation with an intentionally generated leak in anaesthetised patients. Recordings were made in ultraclean operating theatres and compared against the aerosol generated by tidal breathing and cough manoeuvres. Respiratory aerosol from tidal breathing in 11 patients was reliably detected above the very low background particle concentrations with median [IQR (range)] particle counts of 191 (77-486 [4-1313]) and 2 (1-5 [0-13]) particles.l-1 , respectively, p = 0.002. The median (IQR [range]) aerosol concentration detected during facemask ventilation without a leak (3 (0-9 [0-43]) particles.l-1 ) and with an intentional leak (11 (7-26 [1-62]) particles.l-1 ) was 64-fold (p = 0.001) and 17-fold (p = 0.002) lower than that of tidal breathing, respectively. Median (IQR [range]) peak particle concentration during facemask ventilation both without a leak (60 (0-60 [0-120]) particles.l-1 ) and with a leak (120 (60-180 [60-480]) particles.l-1 ) were 20-fold (p = 0.002) and 10-fold (0.001) lower than a cough (1260 (800-3242 [100-3682]) particles.l-1 ), respectively. This study demonstrates that facemask ventilation, even when performed with an intentional leak, does not generate high levels of bioaerosol. On the basis of this evidence, we argue facemask ventilation should not be considered an aerosol-generating procedure.

Aerosolisation during tracheal intubation and extubation in an operating theatre setting.

Aerosol-generating procedures such as tracheal intubation and extubation pose a potential risk to healthcare workers because of the possibility of airborne transmission of infection. Detailed characterisation of aerosol quantities, particle size and generating activities has been undertaken in a number of simulations but not in actual clinical practice. The aim of this study was to determine whether the processes of facemask ventilation, tracheal intubation and extubation generate aerosols in clinical practice, and to characterise any aerosols produced. In this observational study, patients scheduled to undergo elective endonasal pituitary surgery without symptoms of COVID-19 were recruited. Airway management including tracheal intubation and extubation was performed in a standard positive pressure operating room with aerosols detected using laser-based particle image velocimetry to detect larger particles, and spectrometry with continuous air sampling to detect smaller particles. A total of 482,960 data points were assessed for complete procedures in three patients. Facemask ventilation, tracheal tube insertion and cuff inflation generated small particles 30-300 times above background noise that remained suspended in airflows and spread from the patient's facial region throughout the confines of the operating theatre. Safe clinical practice of these procedures should reflect these particle profiles. This adds to data that inform decisions regarding the appropriate precautions to take in a real-world setting.

Regulation of energy metabolism during social interactions in rainbow trout: a role for AMP-activated protein kinase.

Rainbow trout (Oncorhynchus mykiss) confined in pairs form social hierarchies in which subordinate fish typically experience fasting and high circulating cortisol levels, resulting in low growth rates. The present study investigated the role of AMP-activated protein kinase (AMPK) in mediating metabolic adjustments associated with social status in rainbow trout. After 3 days of social interaction, liver AMPK activity was significantly higher in subordinate than dominant or sham (fish handled in the same fashion as paired fish but held individually) trout. Elevated liver AMPK activity in subordinate fish likely reflected a significantly higher ratio of phosphorylated AMPK (phospho-AMPK) to total AMPK protein, which was accompanied by significantly higher AMPKα1 relative mRNA abundance. Liver ATP and creatine phosphate concentrations in subordinate fish also were elevated, perhaps as a result of AMPK activity. Sham fish that were fasted for 3 days exhibited effects parallel to those of subordinate fish, suggesting that low food intake was an important trigger of elevated AMPK activity in subordinate fish. Effects on white muscle appeared to be influenced by the physical activity associated with social interaction. Overall, muscle AMPK activity was significantly higher in dominant and subordinate than sham fish. The ratio of phospho-AMPK to total AMPK protein in muscle was highest in subordinate fish, while muscle AMPKα1 relative mRNA abundance was elevated by social dominance. Muscle ATP and creatine phosphate concentrations were high in dominant and subordinate fish at 6 h of interaction and decreased significantly thereafter. Collectively, the findings of the present study support a role for AMPK in mediating liver and white muscle metabolic adjustments associated with social hierarchy formation in rainbow trout.

Cystic lesion of the ventriculus terminalis in an adult.

We present a 40-year-old man with conus medullaris syndrome secondary to a cystic lesion of the ventriculus terminalis (CLVT) and review the relevant literature. The patient presented with 4 years of worsening right leg weakness, and examination showed bilateral fasciculations and hyporeflexia. MRI showed a cystic lesion at T11-12. He was managed with a T11-12 laminectomy and fenestration of an intramedullary cyst. A total of 32 patients, including ours, have been described since 1968: 24 were female with a mean age of 46.6 years. All patients presented symptomatically: five were managed conservatively, four using percutaneous aspiration under MRI guidance, and 22 with open surgery. We conclude that symptomatic patients are best managed surgically, although percutaneous aspiration is an emerging technique.

Exposure to low concentrations of dissolved ammonia promotes growth rate in walleye Sander vitreus.

The objective of the current study was to examine whether sublethal (moderate) levels of dissolved ammonia may be beneficial to growth in juvenile walleye Sander vitreus (recent evidence in juvenile rainbow trout Oncorhynchus mykiss has shown significant increases in protein synthesis in the presence of moderately elevated concentrations of dissolved ammonia). Moderately elevated dissolved ammonia concentrations between 100 and 300 micromol l(-1) suppressed routine aerobic metabolic activity by 20% during acute trials (2 h), while promoting specific growth rate (>50%) and elevating whole body soluble protein content by 20% in the early stages (14-42 days) in chronic ammonia exposure experiments. Juvenile S. vitreus held at ammonia concentrations between 107.6 +/- 5.5 and 225.5 +/- 4.7 micromol l(-1) (mean +/-s.e.) grew significantly faster than control fish and significantly reduced plasma cortisol levels (<3 microg dl(-1)). Results from this study suggest that chronic exposure to moderate amounts of dissolved ammonia significantly increase growth rates in juvenile S. vitreus by increasing nitrogen accessible for supplementary protein deposition leading to somatic development.

Characterization and expression of a myosin heavy-chain isoform in juvenile walleye Sander vitreus.

In this study, myosin, the major component of myofibrillar protein in the skeletal muscle, was characterized and its expression was monitored during growth in juvenile walleye Sander vitreus. First, the coding region of myosin heavy chain (MyHC) from the fast skeletal muscle of walleye was amplified by long-distance PCR using a full-length cDNA. Phylogenetic analysis was used to determine the evolutionary relationship of this S. vitreus myosin sequence to other vertebrate myosin sequences. Next, it was established that the myosin isoform was most prevalent in the white muscle, compared with the red and cardiac muscle. Myosin expression was monitored over a series of experiments designed to influence growth. Specifically, change in MyHC mRNA was monitored after acute changes in feeding. Fish exposed to a one-week fasting period showed significant decreases in MyHC mRNA levels by the end of the fast. The effect of feeding was also examined more closely over a 24 h period after feeding, but results showed no significant change in myosin expression levels through this time period. Finally, fish with higher growth rates had higher MyHC mRNA and protein expression levels. This study indicates that MyHC mRNA expression is sensitive to the factors that may influence growth in juvenile S. vitreus.

Co-existing granular cell tumor and adenocarcinoma of the lung: a case report and review of the literature.

Granular cell tumor (GCT) of the lung is a rare tumor, constituting less than 10% of all GCTs. It is a multicentric tumor and infiltrates into adjoining tissue, but malignant GCT of the lung has not been reported. Diagnosis is usually obtained with bronchoscopic biopsy. Treatment options include bronchoscopic extirpation, laser therapy, and sleeve resection. We present a case of GCT co-existing with adenocarcinoma of the lung and review the literature.

Estimation of residues of carbofuran and its metabolites in sugarcane and soil by derivatization with 1-fluoro-2,4-dinitrobenzene and gas chromatography with nitrogen-phosphorus detection.

Residues of carbofuran and its metabolites were studied in sugarcane plants and soil after application at 1 and 2 kg/ha. The residues of carbofuran and its metabolites were extracted by refluxing with 0.25N HCI, partitioned into dichloromethane, and cleaned up on acidic alumina. The respective 7-phenols of carbofuran, 3-ketocarbofuran, and 3-hydroxycarbofuran were destroyed by treatment with ceric ammonium sulfate, and the residues were derivatized with 1-fluoro-2,4-dinitrobenzene. The derivatives were estimated by gas chromatography with nitrogen-phosphorus detection. The concentration of 3-hydroxycarbofuran in sugarcane plants remained higher and persisted longer than that of the parent compound. Carbofuran-derived residues were not detected in cane juice. Soil samples were found to contain only carbofuran, which declined at a very fast rate that followed a first-order kinetics rate of reaction.

Temporomandibular joint dislocation and deafness from a cricket ball injury.

Cricket is a national sport in some countries and can be potentially hazardous. We report an incident of a cricket ball impact to the chin, which resulted in posterior dislocation of both temporomandibular joints and bilateral mixed deafness. There appear to be no similar case reports in the literature.

Cervical necrotizing fasciitis and tonsillitis.

We present a case of cervical necrotizing fasciitis following quinsy in a previously fit and healthy man. This is a potentially fatal condition with few specific clinical signs that requires early diagnosis and surgical debridement. Other features of the disease are discussed.

Parapharyngeal masses. Report de 4 cases.

The reduced incidence of inflammatory pathology in the head and neck over the last 20 years has diminished the clinical importance of the potential fascial spaces in this region. However, the parapharyngeal space, because of its contents, is still important. Lesions in this region have variable presentations and their management often requires a multidisciplinary approach. The anatomy of this space is the key to the understanding of the pathophysiological effects from expanding lesions occurring within it. We report 4 unusual cases to illustrate the management policy and highlight the pitfalls of lesions in this area.

Craniofacial resection. An alternative incision and skull base repair.

Neoplasia of the superior group of paranasal sinuses (frontal, ethmoidal and sphenoidal) has an extremely poor prognosis. Resection, preceded or followed by radiotherapy offers a 5 year survival of less than 30% (1). Satisfactory surgical excision has been undermined by difficulties of access to the cribriform plate area, a common site for residual disease. Furthermore the practice of piecemeal removal invariably resulted in inadequate clearance. The craniofacial approach allows not only excellent access to the anterior skull base but also in bloc excision. The results of treating 7 patients with craniofacial resection for tumours in this area are presented. Particular reference is made to a horizontal forehead skin crease incision for intracranial access. A new technique using a combination of surgical, pericranium, partial thickness skin and fibrin glue to repair the skull base defect is described.

Aesthetic surgery for microtia.

We describe here a technique for reconstruction of the external ear based upon an autogenous costal cartilage graft which is inserted into a cutaneous pocket dissected in the auricular area. Three subsequent procedures are then performed: rotation of the ear-lobe; reconstruction of the tragus; and elevation of the auricle. The ideal age for reconstruction is about 7 years. This technique was originally described by Brent, who has a very extensive experience with this kind of surgery. Skin deficiencies can be overcome by using either a temporo-parietal fascial flap or a skin expander.

The middle ear in cleft palate children pre and post palatal closure.

A multicentre prospective trial was commenced in July 1984 to establish the incidence of otitis media with effusion (OME) in children born with a cleft of the palate. Additionally, the data recorded would allow an assessment of the effect of palatal closure on middle ear function. Prior to palatal closure, 97% of ears in a group of 50 patients had otitis media with effusion (OME). The insertion of a long-term ventilation tube provided a means of aeration of one ear with the non-ventilated ear acting as a control. Eighty percent of control ears had persistent OME during a 24-month follow-up period post palatal repair. It would seem that OME is universally present in children with a cleft palate prior to 4 months of age and this incidence is only marginally diminished by palatal surgery. The liaison between plastic surgical and ENT units should be even closer than before in order to manage these patients satisfactorily.

Posterior fossa ganglioglioma--an unusual cause of hearing loss.

Intracranial or spinal gangliogliomas of the CNS are rare tumours. Although several cases have been reported over the years, controversy still remains as to their origin, treatment and prognosis. A case of an eight-year-old girl with a ganglioglioma in the cerebellum with extension into the cerebello-pontine angle is described. The histological basis of the diagnosis is discussed and a review of the literature is presented.