Heliox in children with croup: a strategy to hasten improvement

OBJECTIVE

Upper airway obstruction is responsive to the reduction in airflow turbulence provided by helium/oxygen (heliox) admixture. Our pediatric critical care transport team (PCCTT) has used heliox for children with upper airway obstruction from croup. We sought to describe our experience with heliox on transport and hypothesized that heliox-treated children with croup would show a more rapid clinical improvement.

METHODS

Children with croup transported by our PCCTT and admitted to the PICU were evaluated. We analyzed pretransport care, transport interventions, and outcomes. Croup scores (Modified Taussig) were assigned retrospectively according to respiratory therapy charting. Data were analyzed using appropriate statistical tests, including Pearson's chi-square test, Fisher's exact test, Mann-Whitney U rank comparison, and two-sample t-test.

RESULTS

Thirty-five children met inclusion criteria. Demographics were similar between groups. The pretransport medical care was similar between groups. Children receiving heliox had a higher baseline croup score [mean (SD) = 5.7(2.3) vs no heliox 2.9 (2.0), P < 0.001]. The improvement in croup scores over the first 60 minutes of transport was more rapid in the heliox-treated children (P < 0.001). There was no difference in the number of children requiring additional nebulized racemic epinephrine during transport. The PICU length of stay (P = 0.59) and hospital length of stay (P = 0.64) were similar between groups.

CONCLUSION

Heliox added to standard transport treatment for critically ill children with croup provides a more rapid improvement in croup scores. Heliox for croup during transport does not prolong intensive care unit stay. A prospective clinical trial is warranted to evaluate heliox in pediatric transport.

Clinical vignettes: integrated care of cancer patients by oncologists and cardiologists

Because of the paucity of large, randomized trials concerning the cardiac care of patients with cancer, treatment and prevention of chemotherapy-induced cardiotoxicity must rely on insights gained from small trials and case reports as well as the application of guidelines developed for the general population. In these clinical vignettes, we present patients referred by their oncologists to a cardiologist for specialized evaluation and management of cardiotoxicity with the goal of emphasizing the importance of identifying risk factors for cardiotoxicity, initiating evidence-based therapy, and establishing a close collaboration between oncologists and cardiologists.

Renalase deficiency aggravates ischemic myocardial damage

Chronic kidney disease (CKD) leads to an 18-fold increase in cardiovascular complications not fully explained by traditional risk factors. Levels of renalase, a recently discovered oxidase that metabolizes catecholamines, are decreased in CKD. Here we show that renalase deficiency in a mouse knockout model causes increased plasma catecholamine levels and hypertension. Plasma blood urea nitrogen, creatinine, and aldosterone were unaffected. However, knockout mice had normal systolic function and mild ventricular hypertrophy but tolerated cardiac ischemia poorly and developed myocardial necrosis threefold more severe than that found in wild-type mice. Treatment with recombinant renalase completely rescued the cardiac phenotype. To gain insight into the mechanisms mediating this cardioprotective effect, we tested if gene deletion affected nitrate and glutathione metabolism, but found no differences between hearts of knockout and wild-type mice. The ratio of oxidized (NAD) to reduced (NADH) nicotinamide adenine dinucleotide in cardiac tissue, however, was significantly decreased in the hearts of renalase knockout mice, as was plasma NADH oxidase activity. In vitro studies confirmed that renalase metabolizes NADH and catecholamines. Thus, renalase plays an important role in cardiovascular pathology and its replacement may reduce cardiac complications in renalase-deficient states such as CKD.

Pulmonary Phialemonium curvatum phaeohyphomycosis in a Standard Poodle dog

Phialemonium curvatum, frequently misidentified as an Acremonium species, is reported here as a new agent of pulmonary phaeohyphomycosis in a Standard Poodle dog, and added as a new species in the genus to cause mycoses in canines. In vitro susceptibility data, for both human and animal isolates, suggests resistance to amphotericin B and susceptibility to the triazole agents itraconazole, voriconazole, and posaconazole.

Distribution and fine-scale spatial-genetic structure in British wild cherry (Prunus avium L.)

Insights into the within-population spatial-genetic structure (SGS) of forest tree species, where little is known regarding seed and pollen dispersal patterns, enhance understanding of their ecology and provide information of value in conservation and breeding. This study utilised 13 polymorphic simple sequence repeat loci to investigate the impact of asexual recruitment, management regime and tree size on the development of SGS in wild cherry (Prunus avium L). Only 246 genotypes were identified in the 551 trees sampled, reflecting significant levels of clonal reproduction in both managed and unmanaged populations. Naturally regenerated wild cherry was spatially aggregated under both management regimes. However, in the managed population, sexually derived trees accounted for a greater proportion of the smaller size classes, whereas vegetatively produced trees dominated the smaller size classes in the unmanaged population. High overall SGS values (Sp 0.030-Sp 0.045) were observed when considering only sexually derived genets and kinship coefficients were significant up to the 120 m distance class for both populations. The inclusion of clonal ramets in the analysis significantly increased the overall SGS (Sp 0.089-Sp 0.119) as well as kinship coefficients in the 40-80 m distance classes, illustrating the dramatic impact of vegetative propagation on SGS in this species. Increased spatial aggregation and regeneration appeared to be concomitant with increased SGS in the 40 m distance class in the unmanaged population. Neighbourhood size estimates were relatively small for both populations and kinship coefficients were found to decline with distance under both management regimes, suggesting that common mechanisms may restrict gene dispersal in wild cherry.

Isolation of S-locus F-box alleles in Prunus avium and their application in a novel method to determine self-incompatibility genotype

This study characterises a series of 12 S-locus haplotype-specific F-box protein genes (SFB) in cherry (Prunus avium) that are likely candidates for the pollen component of gametophytic self-incompatibility in this species. Primers were designed to amplify 12 SFB alleles,including the introns present in the 50 untranslated region;sequences representing the S-alleles S1, S2, S3, S4, S40, S5,S6, S7, S10, S12, S13 and S16 were cloned and characterized. [The nucleotide sequences reported in this paper have been submitted to the EMBL/GenBank database under the following accession numbers: PaSFB1(AY805048), PaSFB2 (AY805049), PaSFB3 (AY805057),PaSFB4 (AY649872), PaSFB40 (AY649873), PaSFB5(AY805050), PaSFB6 (AY805051), PaSFB7 (AY805052),PaSFB10 (AY805053), PaSFB12 (AY805054), PaSFB13(AY805055), PaSFB16 (AY805056).] Though the coding regions of six of these alleles have been reported previously,the intron sequence has previously been reported only for S6. Analysis of the introns revealed sequence and length polymorphisms. A novel, PCR-based method to genotype cultivars and wild accessions was developed which combines fluorescently labelled primers amplifying the intron of SFB with similar primers for the first intron of S-RNase alleles. Intron length polymorphisms were then ascertained using a semi-automated sequencer. The convenience and reliability of this method for the determination of the self-incompatibility (SI) genotype was demonstrated both in sweet cherry cultivars representing alleles S1 to S16 and in individuals from a wild population encompassing S-alleles S17 to S22. This method will greatly expedite SI characterisation in sweet cherry and also facilitate large-scale studies of self-incompatibility in wild cherry and other Prunus populations.

Long-lasting potentiation of a single-dose of rocuronium by amikacin: case report

We report for the first time to our knowledge long-lasting (4 hours) potentiation of single intubating dose of rocuronium by a single bolus of amikacin given 55 minutes later in a woman having no precipitating factor (renal failure, hepatic failure, ionic disorder, other drugs influencing neuromuscular function). This patient had received the same rocuronium dose one month sooner in similar circumstances (without aminoglycoside antibiotic drug) and had not presented any prolonged neuromuscular blockade at this time. Neuromuscular blockade should be monitored in every patient receiving aminoglycoside antibiotic with even a single intubating dose of neuromuscular blocking drug.

Association of a novel high molecular weight, serine-rich protein (SrpA) with fibril-mediated adhesion of the oral biofilm bacterium Streptococcus cristatus

The surface of the oral plaque bacterium Streptococcus cristatus is decorated with a lateral tuft of fibrils. The fibrillar tuft functions in the adhesion of S. cristatus to heterologous bacterial species in the plaque biofilm. The tuft typically consists of a densely packed fringe of shorter fibrils 238 +/- 19 nm long with longer, less abundant fibrils 403 +/- 66 nm long projecting through the fringe of short fibrils. The two types of fibrils in the tufts of S. cristatus have been refractory to biochemical separation, complicating their characterization. A hexadecane partition assay was used to enrich for subpopulations of S. cristatus CR311 (type strain NCTC 12479) having distinct fibrillar morphotypes. Negative staining in the TEM revealed that cells of a hydrophobic subpopulation of S. cristatus (CR311var1) carried only the long fibrils (395 +/- 32 nm). A hydrophilic subpopulation of S. cristatus (CR311var3) consisted of mixed morphotypes having no fibrils or remnant short fibrils (223 +/- 49 nm). No long fibrils were observed on any cells in the CR311var3 subpopulation. The CR311var3 morphotype, unlike the wild-type strain and CR311var1, was not able to form corncobs with either Corynebacterium matruchotii or Fusobacterium nucleatum. Variant CR311var3 did not express the novel gene srpA, which encodes a high molecular weight (321,882 Da) serine-rich protein, SrpA. The SrpA protein contains two extensive repeat motifs of 17 and 71 amino acids and a gram-positive cell wall anchor consensus sequence (LPNTG). The unusual properties of SrpA most closely resemble those of Fap1, the fimbrial-associated adhesin protein of Streptococcus parasanguis. The association of long fibrils, high surface hydrophobicity, ability to form corncob formations, and expression of the srpA gene suggest that SrpA is a long fibril protein in S. cristatus.

Installation of the hand influences acceleromyography measurement. A comparison with mechanomyography during neuromuscular recovery

Acceleromyography is commonly used to monitor perioperative neuromuscular blockade and to prevent residual neuromuscular blockade at the time of tracheal extubation. However, there are problems associated with this method, such as obtaining stable values, particularly beneath the surgical fields. We compared TOF ratios obtained on both hands simultaneously using on one side mechanomyography and on the other acceleromyography, installed in four different ways: the hand simply lying on a board, fingers fixed with tape, use of the hand adaptor or the TOF-tube. Further to maintaining free thumb movement, the TOF-tube improves feasibility of acceleromyography by reducing the measurement variability while retaining accuracy.

Comparative mapping between quercus and castanea using simple-sequence repeats (SSRs)

Simple sequence repeat (SSR) markers from Quercus and Castanea were used for comparative mapping between Quercus robur (L.) and Castanea sativa (Mill.). We tested the transferability of SSRs developed in Quercus to Castanea and vice-versa. In total, 47% (25) of the Quercus SSRs and 63% (19) of the Castanea SSRs showed a strong amplification product in the non-source species. From these 44 putative comparative anchor tags, 19 (15 from Quercus and 4 from Castanea) were integrated in two previously established genetic linkage maps for the two genera. SSR loci were sequenced to confirm the orthology of the markers. The combined information from both genetic mapping and sequence analysis were used to determine the homeology between seven linkage groups, aligned on the basis of pairs or triplets of common markers, while two additional groups were matched using a single microsatellite marker. Orthologous loci identified between Q. robur and C. sativa will be useful as anchor loci for comparative mapping studies within the Fagaceae family.

Graduated driver licensing for reducing motor vehicle crashes among young drivers

BACKGROUND

Graduated driver licensing (GDL) has been proposed as a means of reducing crash rates among novice drivers by gradually introducing them to higher risk driving situations.

OBJECTIVES

To examine the effectiveness of GDL systems in reducing crash rates of young drivers.

SEARCH STRATEGY

Studies were identified through searches of MEDLINE, EMBASE, CINAHL, Healthstar, Web of Science, NTIS Bibliographic Database, TRIS Online, SIGLE, the World Wide Web, relevant conference proceedings, consultation with experts and authors, and reference lists. The search was not restricted by language or publication status.

SELECTION CRITERIA

Studies were included if: 1) they compared outcomes pre- and post-implementation of a GDL program within the same jurisdiction, 2) comparisons were made between jurisdictions with and without GDL, or 3) both. Studies had to report at least one objective, quantified outcome. Two reviewers independently screened searches and assessed the full text of potentially relevant studies for inclusion using a standard form.

DATA COLLECTION AND ANALYSIS

Data were extracted by one reviewer and checked by a second. Additional data were requested from authors. Results were not pooled due to substantial heterogeneity between studies. Percentage change was calculated for each year after the intervention, using one year prior to the intervention as the baseline rate. Results were adjusted by internal controls. Analyses were stratified by different denominators (population, licensed drivers). Results were calculated for the different crash types (overall, injury, fatal, night-time, alcohol, and those resulting in hospitalization). Results were presented for 16 year-olds alone and all teenage drivers combined.

MAIN RESULTS

We included 13 studies evaluating 12 GDL programs that were implemented between 1979 and 1998 in the US (n=7), Canada (3), New Zealand (1), and Australia (1). Programs varied in their restrictions during the intermediate stage: e.g. night curfews (8); limitations of extra passengers (2); roadway restrictions (1). Based on the Insurance Institute for Highway Safety classification scheme, no programs were good, six were acceptable, five were marginal, and one was poor. Reductions in crash rates were seen in all jurisdictions and for all crash types. Among 16 year-old drivers, the median decrease in per population overall crash rates during the first year was 31% (range 26-41%). Per population injury crash rates were similar (median 28%, range 4-43%). Results for all teenage drivers, rates per licensed driver, and rates adjusting for internal controls were generally reduced when comparing within jurisdictions.

REVIEWERS' CONCLUSIONS

The existing evidence shows that GDL is effective in reducing the crash rates of young drivers, although the magnitude of the effect is unclear. The conclusions are supported by consistent direction of the findings, and the temporal relationship and plausibility of the association. The reviewers have made recommendations for primary research on GDL (e.g. study methods, standardized reporting of outcomes and results, long-term follow-up). The project has also shown what is needed to carry out systematic reviews of observational studies (e.g. quality assessment instruments).

Glucocorticoids for croup

BACKGROUND

Since the initial version of this systematic review in 1997, a number of randomised trials examining the benefit of glucocorticoids have been published, reflecting a continued interest in the use of glucocorticoids to treat patients with croup. The objective of this review was to provide evidence to guide clinicians in their treatment of patients with croup by determining the effectiveness of glucocorticoids and to identify areas of uncertainty for future research.

OBJECTIVES

To determine the effect of glucocorticoids for children with croup.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL) (issue 1, 2003), MEDLINE (January 1966 to April 2003) and Excerpta Medica/EMBASE (January 1974 to August 2003). We also contacted authors of identified croup trials published in the last ten years to inquire about additional published or unpublished trials.

SELECTION CRITERIA

Randomised controlled trials that examine children with croup and objectively measure the effectiveness of glucocorticoid treatment.

DATA COLLECTION AND ANALYSIS

Based on review of the title and abstract (when available), two researchers identified studies for potential relevance. The complete text was retrieved and using a priori inclusion criteria, the studies were independently reviewed for relevance by two reviewers. Two observers independently assessed quality. Differences with respect to inclusion status and quality assessment were resolved by consensus. Data were extracted using a structured form by one reviewer and checked for accuracy by a second reviewer. Standard statistical analyses were performed.

MAIN RESULTS

Thirty-one studies were deemed relevant for inclusion (N = 3736). Glucocorticoid treatment was associated with an improvement in the Westley score at six hours with a weighted mean difference of -1.2 (95% confidence interval -1.6 to -0.8) and at 12 hours -1.9 (-2.4 to -1.3); at 24 hours this improvement was no longer significant (-1.3, -2.7 to 0.2). Fewer return visits and/or (re)admissions occurred in patients treated with glucocorticoids (relative risk 0.50; 0.36 to 0.70). Length of time spent in accident and emergency or hospital (weighted mean difference 12 hours, five to 19 hours) was significantly decreased for patients treated with glucocorticoids. Use of epinephrine decreased for children treated with a glucocorticoid (risk difference 10%; 1 to 20). No other decreases in additional treatments were found in the primary analysis. Publication bias does not impact results importantly. No between-trial significant differences were found between populations with mild and moderate croup. Oral dexamethasone may be superior to intramuscular dexamethasone.

REVIEWER'S CONCLUSIONS

Dexamethasone and budesonide are effective in relieving the symptoms of croup as early as six hours after treatment. Fewer return visits and/or (re)admissions are required and the length of time spent in hospital is decreased in inpatients. Dexamethasone is also effective in mild croup populations. Research is required to examine the most beneficial method for disseminating croup practice guidelines and to increase the uptake of evidence to improve outcomes.