Acute kidney injury development in polytrauma and the safety of early repeated contrast studies: A retrospective cohort study.

BACKGROUND: The role of repeat intravenous contrast doses beyond initial contrast imaging in the development of acute kidney injury (AKI) for multiple injury patients admitted to the intensive care unit (ICU) is not fully understood. We hypothesized that additional contrast doses are potentially modifiable risk factors for worse outcomes. METHODS: An 8-year retrospective study of our institutional prospective postinjury multiple organ failure database was performed. Adult ICU admissions that survived >72 hours with Injury Severity Score (ISS) of >15 were included. Patients were grouped based on number of repeat contrast studies received after initial imaging. Initial vital signs, resuscitation data, and laboratory parameters were collected. Primary outcome was AKI (Kidney Disease: Improving Global Outcomes criteria), and secondary outcomes included contrast-induced acute kidney injury (CI-AKI; >25% or >44 µmol/L increase in creatinine within 72 hours of contrast administration), multiple organ failure, length of stay, and mortality. RESULTS: Six-hundred sixty-three multiple injury patients (age, 45.3 years [SD, 9.1 years]; males, 75%; ISS, 25 (interquartile range, 20-34); mortality, 5.4%) met the inclusion criteria. The incidence of AKI was 13.4%, and CI-AKI was 14.5%. Multivariate analysis revealed that receiving additional contrast doses within the first 72 hours was not associated with AKI (odds ratio, 1.33; confidence interval, 0.80-2.21; p = 0.273). Risk factors for AKI included higher ISS ( p < 0.0007), older age ( p = 0.0109), higher heart rate ( p = 0.0327), lower systolic blood pressure ( p = 0.0007), and deranged baseline blood results including base deficit ( p = 0.0042), creatinine ( p < 0.0001), lactate ( p < 0.0001), and hemoglobin ( p = 0.0085). Acute kidney injury was associated with worse outcomes (ICU length of stay: 8 vs. 3 days, p < 0.0001; mortality: 16% vs. 3.8%, p < 0.0001; MOF: 42% vs. 6.6%, p < 0.0001). CONCLUSION: There is a limited role of repeat contrast administration in AKI development in ICU-admitted multiple injury patients. The clinical significance of CI-AKI is likely overestimated, and it should not compromise essential secondary imaging from the ICU. Further prospective studies are needed to verify our results. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level III.

Current state of perinatal postmortem magnetic resonance imaging: European Society of Paediatric Radiology questionnaire-based survey and recommendations.

BACKGROUND: Postmortem magnetic resonance imaging (MRI) in perinatal and childhood deaths is increasingly used as a noninvasive adjunct or alternative to autopsy. Imaging protocols vary between centres and consensus guidelines do not exist. OBJECTIVE: Our aim was to develop practical, standardised recommendations for perinatal postmortem MRI. MATERIALS AND METHODS: Recommendations were based on the results of two surveys regarding local postmortem MRI practices sent electronically to all 14 members of the European Society of Paediatric Radiology (ESPR) Postmortem Imaging Task Force and 17 members of the International Society of Forensic Radiology and Imaging Task Force (25 different centres). RESULTS: Overall, 11/14 (78.6%) respondents from different institutions perform postmortem MRI. All of these centres perform postmortem MRI for perinatal and neonatal deaths, but only 6/11 (54.5%) perform imaging in older children. CONCLUSION: We propose a clinical standard for postmortem MRI sequences plus optional sequences for neuroimaging and cardiac anatomy depending on available scanning time and referral indications.

Diagnostic assessment of foetal brain malformations with intra-uterine MRI versus perinatal post-mortem MRI.

PURPOSE: To evaluate differences in diagnostic yield of intra-uterine foetal (iuMR) and post-mortem MRI (PMMR) for complex brain malformations, using autopsy as the reference standard. METHODS: In this retrospective, multicentre study spanning 2 years, we reviewed 13 terminated singleton pregnancies with a prenatal ultrasound finding of complex foetal cerebral abnormalities, referred for both iuMR and PMMR. The iuMR and PMMR studies of the brain were reported independently by two groups of radiologists, blinded to each other's reports. Descriptive statistics were used to compare differences in intracranial abnormalities with autopsy (and genetic testing, where present) as reference standard. RESULTS: The median gestational age at termination was 24.6 weeks (IQR 22-29) with median time between delivery and PMMR of 133 h (IQR 101-165). There was full concordance between iuMR and PMMR findings and autopsy in 2/13 (15.3%) cases. Partial concordance between both imaging modalities was present in 6/13 (46.2%) and total discordance in the remainder (5/13, 38.5%). When compared to autopsy, PMMR missed important key findings specifically for neuronal migration and cerebellar anomalies, whereas iuMR appeared to overcall CSF space abnormalities which were less crucial to reaching the final overall diagnosis. CONCLUSIONS: iuMR should be performed to improve foetal phenotyping where there is a prenatal ultrasound for complex foetal brain abnormalities. Reliance on PMMR alone is likely to result in misdiagnosis in a majority of cases.

A re-evaluation of the scratch test for locating the liver edge.

BACKGROUND: A reliable and accurate estimation of liver size by physical examination is an important aspect of the clinical assessment of a patient. The scratch test uses auscultation to detect the lower liver edge by using the difference in sound transmission through the abdominal cavity over solid and hollow organs. The test is thought to be particularly useful if the abdomen is tense, distended, obese, or very tender. Although the sign is often taught to medical students and residents, the value of the technique for detecting the liver edge has become controversial. METHODS: The study was performed in two parts. In the first part, 18 patients undergoing upper abdominal ultrasound as outpatients were randomly selected and the scratch test was performed by two raters independently, followed by ultrasound (USG) as the reference standard. In the second part of the study, the two raters independently performed the scratch test on separate randomly selected patients (15 patients by rater 1, and 16 patients by rater 2), followed by USG. RESULTS: Agreement between raters on the scratch test was very high, with an intra-class correlation coefficient of 0.97. The agreement between the raters and the USG was 0.37 using Spearman's rho. A Bland -Altman plot indicated that, on average, raters underestimated the distance from the right costal margin to the liver edge by only about 2.4 centimeters compared to USG. This translates into 37% and 54% of raters' estimates falling within 2 and 3 cm of USG estimates. Each unit increase in BMI increased the discrepancy between raters and USG by 0.26 cm (p = 0.012). CONCLUSION: The scratch test has very high reproducibility and overall agreement between the scratch test and USG was moderate, with a spearman's rho of 0.37. The accuracy may potentially be improved by using the point of initial sound transmission rather than the point of maximal transmission. We conclude that the scratch test deserves further investigation.

The major volatile organic compound emitted from Arabidopsis thaliana flowers, the sesquiterpene (E)-ß-caryophyllene, is a defense against a bacterial pathogen.

Flowers have a high risk of pathogen attack because of their rich nutrient and moisture content, and high frequency of insect visitors. We investigated the role of (E)-ß-caryophyllene in floral defense against a microbial pathogen. This sesquiterpene is a common volatile compound emitted from flowers, and is a major volatile released from the stigma of Arabidopsis thaliana flowers. Arabidopsis thaliana lines lacking a functional (E)-ß-caryophyllene synthase or constitutively overexpressing this gene were challenged with Pseudomonas syringae pv. tomato DC3000, which is a bacterial pathogen of brassicaceous plants. Flowers of plant lines lacking (E)-ß-caryophyllene emission showed greater bacterial growth on their stigmas than did wild-type flowers, and their seeds were lighter and misshapen. By contrast, plant lines with ectopic (E)-ß-caryophyllene emission from vegetative parts were more resistant than wild-type plants to pathogen infection of leaves, and showed reduced cell damage and higher seed production. Based on in vitro experiments, (E)-ß-caryophyllene seems to act by direct inhibition of bacterial growth, rather than by triggering defense signaling pathways. (E)-ß-Caryophyllene thus appears to serve as a defense against pathogens that invade floral tissues and, like other floral volatiles, may play multiple roles in defense and pollinator attraction.

Variation of herbivore-induced volatile terpenes among Arabidopsis ecotypes depends on allelic differences and subcellular targeting of two terpene synthases, TPS02 and TPS03.

When attacked by insects, plants release mixtures of volatile compounds that are beneficial for direct or indirect defense. Natural variation of volatile emissions frequently occurs between and within plant species, but knowledge of the underlying molecular mechanisms is limited. We investigated intraspecific differences of volatile emissions induced from rosette leaves of 27 accessions of Arabidopsis (Arabidopsis thaliana) upon treatment with coronalon, a jasmonate mimic eliciting responses similar to those caused by insect feeding. Quantitative variation was found for the emission of the monoterpene (E)-beta-ocimene, the sesquiterpene (E,E)-alpha-farnesene, the irregular homoterpene 4,8,12-trimethyltridecatetra-1,3,7,11-ene, and the benzenoid compound methyl salicylate. Differences in the relative emissions of (E)-beta-ocimene and (E,E)-alpha-farnesene from accession Wassilewskija (Ws), a high-(E)-beta-ocimene emitter, and accession Columbia (Col-0), a trace-(E)-beta-ocimene emitter, were attributed to allelic variation of two closely related, tandem-duplicated terpene synthase genes, TPS02 and TPS03. The Ws genome contains a functional allele of TPS02 but not of TPS03, while the opposite is the case for Col-0. Recombinant proteins of the functional Ws TPS02 and Col-0 TPS03 genes both showed (E)-beta-ocimene and (E,E)-alpha-farnesene synthase activities. However, differential subcellular compartmentalization of the two enzymes in plastids and the cytosol was found to be responsible for the ecotype-specific differences in (E)-beta-ocimene/(E,E)-alpha-farnesene emission. Expression of the functional TPS02 and TPS03 alleles is induced in leaves by elicitor and insect treatment and occurs constitutively in floral tissues. Our studies show that both pseudogenization in the TPS family and subcellular segregation of functional TPS enzymes control the variation and plasticity of induced volatile emissions in wild plant species.

Floral visitation and reproductive traits of Stamenoid petals, a naturally occurring floral homeotic variant of Capsella bursa-pastoris (Brassicaceae).

Homeotic changes played a considerable role during the evolution of flowers, but how floral homeotic mutants initially survive in nature has remained enigmatic. To better understand the evolutionary potential of floral homeotic mutants, we established as a model system Stamenoid petals (Spe), a natural variant of Capsella bursa-pastoris (Brassicaceae). In the flowers of Spe plants, petals are transformed into stamens, whereas all other floral organs are unaffected. In contrast with most other homeotic mutants, the Spe variant occurs in relatively stable populations in the wild. In order to determine how the profound change in floral architecture influences plant performance in the wild, we performed common garden experiments running over 3 years. Here, we show that Spe and wild-type plants attract the same assemblage of floral visitors: mainly hoverflies, wild bees and thrips. However, floral visitation is about twice as frequent in wild-type plants as in Spe plants. Nevertheless, the numbers of seeds per fruit were about the same in both variants. Wild-type plants produced more flowers, fruits and seeds per plant than Spe plants, whereas the germination capacity of Spe seeds was higher than that of the wild-type. Determination of volatile composition revealed monoterpenes and 3,4-dimethylbenzaldehyde, which were detected only in wild-type flowers, presumably because they are produced only by petals. Our data indicate that the similar fitness of Spe and wild-type C. bursa-pastoris in the field results from complex compensation between plant architecture and germination capacity. In contrast, flower structure and floral visitation are only of minor importance, possibly because C. bursa-pastoris is mainly self-pollinating.

A comparison of single-photon emission CT lung scintigraphy and CT pulmonary angiography for the diagnosis of pulmonary embolism.

BACKGROUND: This study compared single-photon emission CT (SPECT) ventilation/perfusion (V/Q) scintigraphy with multislice CT pulmonary angiography (CTPA). METHODS: In a prospective, observational study, 100 patients who were >or= 50 years of age were recruited. Seventy-nine patients underwent both diagnostic 16-detector CTPA, and planar and SPECT V/Q scintigraphy. The agreement between the CTPA and the SPECT V/Q scintigraphy for the diagnosis of pulmonary embolism (PE) was calculated. The sensitivity and specificity of blinded SPECT scintigraphy reporting was calculated against a reference diagnosis made by a panel of respiratory physicians that was provided with CTPA and planar V/Q scintigraphy reports, clinical information, and 3-month follow-up data. RESULTS: The observed percentage of agreement between SPECT V/Q scintigraphy and CTPA data for the diagnosis of PE was 95%. When calculated against the respiratory physicians' reference diagnosis, SPECT V/Q scintigraphy had a sensitivity of 83% and a specificity of 98%. CONCLUSIONS: This study indicates that SPECT V/Q scintigraphy is a viable alternative to CTPA for the diagnosis of PE and has potential advantages in that it was feasible in more patients and had fewer contraindications; lower radiation dose; and, arguably, fewer nondiagnostic findings than CTPA. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry Registration Number: ACTRN12609000089235.

Floral and insect-induced volatile formation in Arabidopsis lyrata ssp. petraea, a perennial, outcrossing relative of A. thaliana.

Volatile organic compounds have been reported to serve some important roles in plant communication with other organisms, but little is known about the biological functions of most of these substances. To gain insight into this problem, we have compared differences in floral and vegetative volatiles between two closely related plant species with different life histories. The self-pollinating annual, Arabidopsis thaliana, and its relative, the outcrossing perennial, Arabidopsis lyrata, have markedly divergent life cycles and breeding systems. We show that these differences are in part reflected in the formation of distinct volatile mixtures in flowers and foliage. Volatiles emitted from flowers of a German A. lyrata ssp. petraea population are dominated by benzenoid compounds in contrast to the previously described sesquiterpene-dominated emissions of A. thaliana flowers. Flowers of A. lyrata ssp. petraea release benzenoid volatiles in a diurnal rhythm with highest emission rates at midday coinciding with observed visitations of pollinating insects. Insect feeding on leaves of A. lyrata ssp. petraea causes a variable release of the volatiles methyl salicylate, C11- and C16-homoterpenes, nerolidol, plus the sesquiterpene (E)-beta-caryophyllene, which in A. thaliana is emitted exclusively from flowers. An insect-induced gene (AlCarS) with high sequence similarity to the florally expressed (E)-beta-caryophyllene synthase (AtTPS21) from A. thaliana was identified from individuals of a German A. lyrata ssp. petraea population. Recombinant AlCarS converts the sesquiterpene precursor, farnesyl diphosphate, into (E)-beta-caryophyllene with alpha-humulene and alpha-copaene as minor products indicating its close functional relationship to the A. thaliana AtTPS21. Differential regulation of these genes in flowers and foliage is consistent with the different functions of volatiles in the two Arabidopsis species.

The twin-arginine signal peptide of PhoD and the TatAd/Cd proteins of Bacillus subtilis form an autonomous Tat translocation system.

The bacterial twin-arginine translocation (Tat) pathway has been recently described for PhoD of Bacillus subtilis, a phosphodiesterase containing a twin-arginine signal peptide. The expression of phoD is co-regulated with the expression of tatA(d) and tatC(d) genes localized downstream of phoD. To characterize the specificity of PhoD transport further, translocation of PhoD was investigated in Escherichia coli. By using gene fusions, we analyzed the particular role of the signal peptide and the mature region of PhoD in canalizing the transport route. A hybrid protein consisting of the signal peptide of beta-lactamase and mature PhoD was transported in a Sec-dependent manner indicating that the mature part of PhoD does not contain information canalizing the selected translocation route. Pre-PhoD, as well as a fusion protein consisting of the signal peptide of PhoD (SP(PhoD)) and beta-galactosidase (LacZ), remained cytosolic in the E. coli. Thus, SP(PhoD) is not recognized by E. coli transport systems. Co-expression of B. subtilis tatA(d)/C(d) genes resulted in the processing of SP(PhoD)-LacZ and periplasmic localization of LacZ illustrating a close substrate specificity of the TatA(d)/C(d) transport system. While blockage of the Sec-dependent transport did not affect the localization of SP(PhoD)-LacZ, translocation and processing was dependent on the pH gradient of the cytosolic membrane. Thus, the minimal requirement of a functional Tat-dependent protein translocation system consists of a twin-arginine signal peptide-containing Tat substrate, its specific TatA/C proteins, and the pH gradient across the cytosolic membrane.