Subglottic acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) is one of the the most common malignancies of childhood and can occasionally present as acute airway obstruction. We present the unusual case of a 1-year-old boy who was referred to our Paediatric Otolaryngology (ENT) clinic with a recurrent history of croup. This is the first reported case of localised ALL presenting as a subglottic mass in a paediatric patient. It highlights the need to have a broader differential diagnosis in children presenting with 'recurrent croup' including extramedullary presentation of leukaemia and to have a low threshold for performing endoscopy in such cases.

Preterm Infant with Congenital Tracheal Diverticulum in the Presence of Esophageal Atresia and Tracheoesophageal Fistula

A 32+4-week-preterm neonate was operated on day 1 for esophageal atresia with tracheoesophageal fistula with a tight primary anastomosis and closure of a tracheoesophageal fistula. Postoperatively, he needed ventilation for 6 days. Post-extubation, he needed continuous positive airway pressure support for increased work of breathing, increasing oxygen requirement, and respiratory acidosis when respiratory support was weaned. Further, during the post-operative period, he had right hemidiaphragmatic paresis and acute lifethreatening events requiring manual high-pressure, non-invasive positive pressure ventilation resuscitation. These complications were considered, and a computed tomography assisted by three-dimensional reconstruction was performed. This revealed a congenital tracheal diverticulum and severe tracheomalacia which was confirmed with microlaryngoscopy and bronchoscopy. The presentation and the diagnostic dilemma surrounding this rare diagnosis are discussed in this case report.

Spontaneous pneumomediastinum

Spontaneous pneumomediastinum is the presence of free air within the mediastinum that is not associated with trauma. It is a rare, self-limiting condition that can cause widespread subcutaneous surgical emphysema. We present the case of a 12-year-old boy who presented with widespread spontaneous surgical emphysema and pneumomediastinum, with no history of trauma or respiratory tract disease. We discuss our assessment of him and management with our multidisciplinary team (MDT), and whether radiological investigations including CT are helpful in such cases. In conclusion, we hypothesised that the child's coughing was the most likely cause of the tracheal rupture leading to the spontaneous surgical emphysema. Spontaneous pneumomediastinum in the paediatric patient is extremely rare. This case highlights how spontaneous pneumomediastinum can be successfully managed conservatively, and how MDT input can be helpful in guiding management in such unusual cases.

Burden of neurological conditions in Canada

Neurological conditions are among the leading causes of disability in the Canadian population and are associated with a large public health burden. An increase in life expectancy and a declining birth rate has resulted in an aging Canadian population, and the proportion of age-adjusted mortality due to non-communicable diseases has been steadily increasing. These conditions are frequently associated with chronic disability and an increasing burden of care for patients, their families and caregivers. The National Population Health Study of Neurological Conditions (NPHSNC) aims to improve knowledge about neurological conditions and their impacts on individuals, their families, caregivers and health care system. The Systematic Review of Determinants of Neurological Conditions, a specific objective within the NPHSNC, is a compendium of systematic reviews on risk factors affecting onset and progression of the following 14 priority neurological conditions: Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), brain tumours (BT), cerebral palsy (CP), dystonia, epilepsy, Huntington's disease (HD), hydrocephalus, multiple sclerosis (MS), muscular dystrophies (MD), neurotrauma, Parkinson's disease (PD), spina bifida (SB), and Tourette's syndrome (TS). The burden of neurological disease is expected to increase as the population ages, and this trend is presented in greater detail for Alzheimer's and Parkinson's disease because the incidence of these two common neurological diseases increases significantly with age over 65 years. This article provides an overview of burden of neurological diseases in Canada to set the stage for the in-depth systematic reviews of the 14 priority neurological conditions presented in subsequent articles in this issue.

Experience and Outcomes of New Developments in Bone Conduction Hearing Technologies in Children

Objectives:

(1) Recognize that percutaneous implant stability in children can be measured using radio frequency analysis (RFA) to generate Implant Stability Quotients (ISQs) and guide sound processor loading. (2) Discuss sound processor loading of the Cochlear BahaÒ (BIA300, BA400) transcutaneous implants at 4-6 weeks in selected children and potential advantages of the transcutaneous ATTRACT implant.

Methods:

We collected data prospectively on all children undergoing implantable BC implants at surgery and follow up appointments. We aimed to assess implant stability over time in children undergoing 1-stage surgery using RFA measurements and investigate the possible implications for earlier loading following surgery. Our experience and outcomes with the ATTRACT transcutaneous device as part of the controlled market release (3+ cases) will also be reviewed.

Results:

Nine children underwent 10 BI300 implants with a mean age of 9 years 4 months. 7 children received the BA400 percutaneous device without soft tissue reduction, with a mean age of 7 years 11 months. Using RFA the mean ISQ at surgery for BI300 implants was 60 and the corresponding unadjusted value for BA400 implants was 50. Changes in ISQs over time are discussed, showing the potential for processor loading at 4-6 weeks.

Conclusions:

Greater implant stability has been demonstrated using the BI300 and BA400 implants, which would subsequently enable early Baha loading. The transcutaneous ATTRACT system potentially offers further improvement in cosmesis and skin inflammation and is likely to have greater acceptance in children with microtia and canal atresia and those who would have previously declined Baha.

First Report of Rhizoctonia spp. Causing a Root Rot of the Invasive Rangeland Weed Lepidium draba in North America

The exotic, invasive perennial rangeland weed Lepidium draba spreads rapidly and reduces native species diversity. The extensive root system of L. draba constitutes 76% of its biomass (4). Thus, searches have been done for biocontrol agents that target root tissue or that may interact with a weevil, Ceutorhynchus assimilis, that causes galls in the crown area of L. draba. An association of Rhizoctonia spp. with root tissue of plants galled by the weevil has been documented in Europe (3). The possible presence of soilborne pathogens similar to those found in the native range has been the subject of L. draba surveys in the United States. One such survey in 2008 detected a few plants with reddened and chlorotic foliage in a stand near Shepherd, MT. Such symptoms typically indicate the occurrence of soilborne diseases on L. draba in the native range of the weed (2). The site had shown a gradual increase in the range of detectable pathogens beginning with foliar pathogens in 1997. In 2010, at the Shepherd site, L. draba plants with similar (but more severe) symptoms to those seen in 2008 were noted in a different area of the stand. Excavation of the roots in both years revealed brown, sunken crown and root cankers. Pieces of root tissue were excised from the lesions and plated on acidified PDA and Ko and Hora medium. A non-sporulating fungus was isolated from three plants. Colonies of the isolates on PDA were typical of known Rhizoctonia spp. The 2010 isolates were determined to be multinucleate using DAPI and were paired with 14 tester (including subgroups) isolates of AG-1 to AG-4 on water agar. Anastomosis was observed between the multinucleate isolates and the AG-2-1 tester isolate. Sequence analysis of ITS of the rDNA of a multinucleate isolate (GenBank KJ545577) indicated 99% similarity with an accession of R. solani AG 2-1 (AB547381). The 2008 isolates were binucleate. A binucleate isolate, KJ545578, had 100% similarity with an isolate of Rhizoctonia spp. AG-A (AY927356). Pathogenicity tests consisted of planting 6-week-old seedlings of L. draba, one per pot, in ten 85-cm-diameter pots of pasteurized soil mix infested with Rhizoctonia-colonized barley grain that had been dried and milled. An inoculum level of ~8 CFU/g (1) of air-dried soil was established by most probable number calculations from fourfold dilutions of infested soil. Controls were the same number of plants in pasteurized potting mix. Results were recorded after 3 months in a greenhouse at 20-25°C. The test was repeated. Typically, R. solani caused mortality of six to eight plants, from which it was re-isolated, whereas binuclate isolates caused stunting and lower dry weight of L. draba. Control plants remained asymptomatic. This is the first report of R. solani and binucleate Rhizoctonia spp. on L. draba in North America. References: (1) A. J. Caesar et al. Plant Dis. 93:1350, 2009. (2) A. J. Caesar et al. Biol. Control 52:140, 2010. (3) A. J. Caesar et al. Plant Dis. 96:145, 2011. (4) R. F. Miller et al. Agronomy J. 86:487, 1994.

The Leicester semi-automated olfactory threshold test--a psychophysical olfactory test for the 21st century

OBJECTIVE

Develop a useful and cost-effective olfactometer for routine clinical use by providing a standardised threshold test for patients with olfactory disorders presenting in the ENT clinic.

METHOD OF STUDY

A prospective study of olfactory thresholds in 48 healthy volunteers on 2 consecutive occasions, undergoing quantitative testing with an olfactometer. Further studies of 10 subjects performing 20 tests and 100 subjects performing a single test were performed. An olfactometer was designed to deliver a semi-automated threshold test for an odour. It contains 8 logarithmic dilutions of an odour along with a control valve operated by software from a laptop computer. Common potential variables for olfactory threshold testing were considered including peak inspiratory flow rate. The odours used were phenethyl alcohol (PEA) and eucalyptol (EUC). Subjects were asked to perform 2 tests within 1 month of each other and the mean threshold score for each was calculated to derive a test-retest score.

MAIN RESULTS

Consistent olfactory thresholds for PEA were achieved with a mean concentration of 10-4. Test-retest reliability score (r(x)) for the olfactometer was r(x) = 0.78 (95% CI 0.67 to 0.89).

PRINCIPAL CONCLUSIONS

The Leicester Olfactometer provides a simple and cost-effective method of reliably assessing olfactory thresholds in the outpatient clinic.

Dosimetric results from the Mir orbital station

The Mir Orbital Station provided a unique platform on which to carry out a variety of space radiation dosimetry measurements. A number of experiments were conducted using a combination of passive detectors on the interior of the Mir during 1996-97. Thermoluminescent detectors were used to measure absorbed dose. CR-39 plastic nuclear track detectors were used to measure the LET spectra > or =5 keV.microm(-1). Results from TLDs and CR-39 PNTDs were combined to determine total dose and dose equivalent. Mean dose rate was found to decrease while mean dose equivalent rate and average quality factor increased with increasing shielding. Secondary particles from proton-induced target fragmentation interactions, not primary HZE particles, were found to be the largest contributor to the LET spectrum above 100 keV.microm(-1). During the 1997 measurements, mean quality factor was found to vary from 1.7 to 2.1 as a function of location within the Mir.

Identified neurons in C. elegans coexpress vesicular transporters for acetylcholine and monoamines

We have identified four neurons (VC4, VC5, HSNL, HSNR) in Caenorhabditis elegans adult hermaphrodites that express both the vesicular acetylcholine transporter and the vesicular monoamine transporter. All four of these cells are motor neurons that innervate the egg-laying muscles of the vulva. In addition, they all express choline acetyltransferase, the synthetic enzyme for acetylcholine. The distributions of the vesicular acetylcholine transporter and the vesicular monoamine transporter are not identical within the individual cells. In mutants deficient for either of these transporters, there is no apparent compensatory change in the expression of the remaining transporter. This is the first report of neurons that express two different vesicular neurotransmitter transporters in vivo.

The cat-1 gene of Caenorhabditis elegans encodes a vesicular monoamine transporter required for specific monoamine-dependent behaviors

We have identified the Caenorhabditis elegans homolog of the mammalian vesicular monoamine transporters (VMATs); it is 47% identical to human VMAT1 and 49% identical to human VMAT2. C. elegans VMAT is associated with synaptic vesicles in approximately 25 neurons, including all of the cells reported to contain dopamine and serotonin, plus a few others. When C. elegans VMAT is expressed in mammalian cells, it has serotonin and dopamine transport activity; norepinephrine, tyramine, octopamine, and histamine also have high affinity for the transporter. The pharmacological profile of C. elegans VMAT is closer to mammalian VMAT2 than VMAT1. The C. elegans VMAT gene is cat-1; cat-1 knock-outs are totally deficient for VMAT immunostaining and for dopamine-mediated sensory behaviors, yet they are viable and grow relatively well. The cat-1 mutant phenotypes can be rescued by C. elegans VMAT constructs and also (at least partially) by human VMAT1 or VMAT2 transgenes. It therefore appears that the function of amine neurotransmitters can be completely dependent on their loading into synaptic vesicles.

Alcohol and drug abusers' reasons for seeking treatment

Clients at two different treatment facilities were asked at assessment how influential each of 10 possible reasons were in their decision to change their alcohol or drug use. Clients at both facilities most often endorsed "weighing the pros and cons of drinking or drug use" and a "warning from spouse." Client's reasons for seeking treatment were also examined in relation to treatment compliance. Three reasons--"weighing the pros and cons," "hitting rock bottom," and experiencing a "major lifestyle change"--were predictive of treatment compliance. Clients who rated any of these reasons as influential were more likely to enter and complete treatment. Although more research is needed, knowledge of clients' reasons for seeking treatment might be useful in treatment matching.

Acyclovir (Zovirax) pharmacokinetics in Quaker parakeets, Myiopsitta monachus

The pharmacokinetics of intravenous (i.v.) and intramuscular (i.m.) single-dose administration of acyclovir were determined in Quaker parakeets. After i.v. injection at a dose of 20 mg/kg of acyclovir, elimination half-life was estimated at 0.65 h, volume of distribution at steady state was 627.65 ml/kg, and clearance was 11.22 ml/kg/min. The estimated pharmacokinetic values after i.m. injection at a dose of 40 mg/kg of acyclovir were an elimination half-life of 0.71 h and a bioavailability of 90.1%. The peak plasma acyclovir concentration occurred at 15 min when the drug was administered i.m. Plasma concentrations of acyclovir were undetectable 4-6 h after i.v. administration and 6-8 h after i.m. administration. Oral (capsules) and intravenous (sodium salt) formulations of acyclovir were given by gavage at 80 mg/kg. Peak concentrations with the sodium salt formulation were lower and developed more slowly than with the capsules. In studies designed to detect excessive drug accumulation or adverse side effects, acyclovir was administered i.m. at 40 mg/kg every 8 h for 7 days. Plasma concentrations were determined 15 min after (peak) and just prior to drug administration (trough). In another study acyclovir was gavaged at a dose of 80 mg/kg every 8 h for 4 days. Acyclovir plasma concentrations were determined just prior to and 2 h after drug administration. In both experiments, the birds maintained normal appetite and weight and did not exhibit excessive drug accumulation. Acyclovir plasma concentrations ranging from 2.07 +/- 1.09 micrograms/ml to 3.93 +/- 1.13 micrograms/ml were maintained for 4 days when acyclovir was administered in the feed and water (sole source of food and water).(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of acyclovir against herpesvirus infection in Quaker parakeets

We evaluated the efficacy of acyclovir against experimentally induced herpesvirus infection (Pacheco's parrot disease) in Quaker parakeets. Thirty-two of 40 birds were challenge-exposed with 0.1 ml of a suspension of herpesvirus (10(4) median cell culture infective doses [CCID50]) given IM. Treatment with acyclovir was started 24 hours later and was continued for 7 days. The birds were allotted to 5 groups of 8 birds each. There was a considerable difference in mortality between groups 1-5. Of 8 bird in each group, 6 died in group 1 (control), 1 died in group 2 (gavage), 3 died in group 3 (low dose, IM), 4 died in group 4 (high dose, IM), and none died in group 5 (contact controls). There was a significant (P = 0.023) difference in mortality between groups 1 and 2, thus the oral form of acyclovir administered by gavage was the most efficacious therapeutic regimen. Clinical signs and death occurred after discontinuation of acyclovir in groups 2 and 3, whereas the mean time of death for the control group was 6 days after challenge exposure. Herpesvirus was recovered by inoculation of chick embryo cell culture with pooled tissue suspensions from all birds that died. Histologic evidence of herpesvirus infection was found in most birds that died, with the control group having the most severe lesions. Surviving Quaker parakeets were transferred to cages with seronegative Quaker parakeets with no known exposure to herpesvirus. There have been no deaths attributable to herpesvirus infection in a period exceeding 2 years.

Subacute effects of respiratory syncytial virus infection on lung function in lambs

We examined the effects of ovine respiratory syncytial virus (RSV) infection on lung mechanics, lung histology, and airway reactivity in lambs. Nine lambs were inoculated with ovine RSV and seven control lambs with normal saline or viral media. Serum neutralization titers were obtained prior to and 3 weeks post-inoculation (PI). Open lung biopsies were performed 1 and 3 weeks PI. Lung mechanics including dynamic compliance (Cdyn), resistance of the lung (RL), and functional residual capacity (FRC) were measured 2 and 6 weeks PI using a plethysmograph. Airway reactivity to aerosolized carbachol, citric acid, and histamine was determined 2 and 6 weeks PI. Most RSV and control lambs were asymptomatic after inoculation. Control lambs had significantly greater average daily weight gain by the third week after inoculation. Seven RSV lambs tested had a fourfold or greater rise in serum neutralization titers, while two control lambs had a fourfold increase. At 2 weeks PI, RSV lambs had significantly lower FRC and higher RL. At 6 weeks RL remained significantly elevated in the RSV lambs. Airway reactivity was not increased in the RSV group. This animal model is useful for studying the effects of RSV infection on lung growth and lung function over time.

Feather and beak dystrophy and necrosis in cockatoos: clinicopathologic evaluations

Several species of imported and captive-bred southeast Asian cockatoos with feather and beak disease (FBD) were evaluated. In recently emerging stained feathers from affected birds, intracytoplasmic magenta to basophilic inclusions of various sizes were found in macrophages and basophil-like cells within the pulp and feather epidermis. Occasionally, amphophilic intranuclear inclusions were seen within degenerated feather epidermal cells. On the basis of electron microscopic findings, intracytoplasmic inclusions were not membrane bound and consisted of crystalline arrays of viral particles (17 to 22 nm in diameter). On the basis of size and conformation, viral particles most closely resembled those of parvovirus or picornavirus. Consistent hematologic or serum enzyme differences were not found among affected or healthy cockatoos. Compared with findings in healthy cockatoos, cockatoos with FBD had significantly lower serum protein concentrations, and results of serum protein electrophoresis indicated that birds with FBD had significantly lower concentrations of prealbumin and gamma-globulin fractions. Mean pre- and post-ACTH plasma corticosterone concentrations of cockatoos with FBD were not significantly different from those of healthy cockatoos. In 8 of 9 affected cockatoos evaluated, serum T4 concentrations before and after thyrotropin stimulation were considered normal.