Analysis of a non-lethal biallelic frameshift mutation in ZMPSTE24 reveals utilization of alternative translation initiation codons

Restrictive dermopathy (RD) is a lethal condition caused by biallelic loss-of-function mutations in ZMPSTE24, whereas mutations preserving residual enzymatic activity of the ZMPSTE24 protein lead to the milder mandibuloacral dysplasia with type B lipodystrophy (MADB) phenotype. Remarkably, we identified a homozygous, presumably loss-of-function mutation in ZMPSTE24 [c.28_29insA, p.(Leu10Tyrfs*37)] in two consanguineous Pakistani families segregating MADB. To clarify how lethal consequences are prevented in affected individuals, functional analysis was performed. Expression experiments supported utilization of two alternative translation initiation sites, preventing complete loss of protein function consistent with the relatively mild phenotypic outcome in affected patients. One of these alternative start codons is newly formed at the insertion site. Our findings indicate that the creation of new potential start codons through N-terminal mutations in other disease-associated genes should generally be taken into consideration in the variant interpretation process.

Multisystem inflammatory syndrome in children during the first two years of the COVID-19 pandemic in Luxembourg

Objective

Estimate the incidence of multisystem inflammatory syndrome (MIS-C) in children (0-15 years), the role of SARS-CoV-2 variants during the first two years of COVID-19 pandemic in Luxembourg; and describe the demographic, biological and clinical characteristics of the patients.

Method

Observational retrospective cohort study. Cases between March 2020 and February 2022 were ascertained from the national registry of MIS-C cases by a retrospective review of medical records. Reported SARS-CoV-2 infections were obtained from the national COVID-19 surveillance system. We calculated monthly MIS-C incidence, the ratio between MIS-C and SARS-CoV-2 infections and associated rate ratios by the periods corresponding to the circulation of different variants.

Results

18 children were diagnosed with MIS-C among 35,200 reported infections. The incidence rate of MIS-C was 7.2 [95% confidence interval (CI) 4.5-11.4] per 1,000,000 person-months. A higher incidence of MIS-C was observed between September and December 2021, corresponding to the circulation of the Delta variant than during the first year of the pandemic (RR 3.6, 95% CI, 1.1-12.3). The lowest rate of MIS-C per infection was observed during the Omicron (RR 0.17, 95% CI, 0.03-0.82). Median age at diagnosis was 6.5 years. Previously healthy children made up 88% of MIS-C cases, none were vaccinated against SARS-CoV-2. 33% required intensive care. All patients recovered fully.

Conclusions

MIS-C incidence and MIS-C risk per infection changed significantly over time during the first two years of COVID-19 pandemic. Monitoring of MIS-C incidence in future SARS-CoV-2 waves will be essential to guide public health interventions and vaccination policies for children.

An exceptional biallelic N-terminal frame shift mutation in ZMPSTE24 leads to non-lethal progeria due to possible utilization of a downstream alternative start codon

Biallelic mutations in ZMPSTE24 are known to be associated with autosomal recessive mandibuloacral dysplasia with type B lipodystrophy (MADB) and lethal restrictive dermopathy (RD), respectively. Disease manifestation is depending on the remaining enzyme activity of the mutated ZMPSTE24 protein. To date, complete loss of function has exclusively been reported in RD cases. In this study, we identified a novel N-terminal homozygous frameshift mutation (c.28_29insA) in a consanguineous family segregating with MADB. An in-depth analysis of the mutated sequence revealed, that the one base pair insertion creates a novel downstream in-frame start codon, which supposedly serves as an alternative translation initiation site (TIS). This possible rescue mechanism would explain the relatively mild clinical outcome in the studied individuals. Our findings demonstrate the necessity for careful interpretation of N-terminal variants potentially effecting translation initiation.

A novel protein truncating mutation in L2HGDH causes L-2-hydroxyglutaric aciduria in a consanguineous Pakistani family

BACKGROUND

L-2-hydroxyglutaric aciduria (L2HGA) is a rare neurometabolic disorder that occurs due to accumulation of L-2-hydroxyglutaric acid in the cerebrospinal fluid (CSF), plasma and urine. The clinical manifestation of L2HGA includes intellectual disability, cerebellar ataxia, epilepsy, speech problems and macrocephaly.

METHODS

In the present study, we ascertained a multigenerational consanguineous Pakistani family with 5 affected individuals. Clinical studies were performed through biochemical tests and brain CT scan. Locus mapping was carried out through genome-wide SNP genotyping, whole exome sequencing and Sanger sequencing. For in silico studies protein structural modeling and docking was done using I-TASSER, Cluspro and AutoDock VINA tools.

RESULTS

Affected individuals presented with cognitive impairment, gait disturbance, speech difficulties and psychomotor delay. Radiologic analysis of a male patient revealed leukoaraiosis with hypoattenuation of cerebral white matter, suggestive of hypomyelination. Homozygosity mapping in this family revealed a linkage region on chromosome 14 between markers rs2039791 and rs781354. Subsequent whole exome analysis identified a novel frameshift mutation NM_024884.3:c.180delG, p.(Ala62Profs*24) in the second exon of L2HGDH. Sanger sequencing confirmed segregation of this mutation with the disease phenotype. The identification of the most N-terminal loss of function mutation published thus far further expands the mutational spectrum of L2HGDH.

479 Penetrating Chest Trauma Causing A Superior Mesenteric Artery-Inferior Vena Cava Fistula and Pancreatic Injury: A Case Report

Penetrating traumatic injuries can present a challenging scenario due to the potential for multisystem involvement requiring swift collaboration between surgical specialities. We present the case of a 66-year-old female who was stabbed in the right posterior chest. CT revealed a diaphragmatic injury, liver laceration involving segments 6/7 with active bleeding, and a posterior superior mesenteric artery (SMA) to anterior inferior vena cava (IVC) fistula. Due to the proximity of the SMA injury to a replaced right hepatic artery origin, the fistulous connection with the suprarenal IVC, and suspected pancreatic and duodenal injuries, a hybrid rather than a purely endovascular approach was taken. A large compliant occlusion balloon was placed percutaneously in the hepatic IVC. Subsequent trauma laparotomy and right medial visceral rotation identified SMA and SMV injuries, which were repaired with temporary supracoeliac aortic clamping. Further kocherisation of the duodenum revealed a 10 cm longitudinal IVC laceration causing sudden large volume venous haemorrhage. This was repaired after control was gained with supracoeliac aortic clamping, infrarenal IVC vessel loop and balloon inflation. An abdominal VAC dressing was applied. Before transfer to ICU, however, 1L of blood was noted in the VAC cannister and a relook laparotomy demonstrated more than 1L of intrabdominal fresh blood. Bleeding vessels around the uncinate process were ligated. After 48 hours, a relook laparotomy revealed no significant bleeding, and the abdomen was closed. A post-operative MRCP demonstrated pancreatic divisum and likely laceration of the aberrant ventral duct. A subsequent peripancreatic collection was managed conservatively.

The effects of farming systems (organic vs. conventional) on dairy cow welfare, based on the Welfare Quality® protocol

Animal welfare in livestock production is of great interest to consumers. The organic farming approach strives to ensure animal welfare based on preventive measures, but there are very few scientific studies that compare the actual differences in animal welfare between organic and conventional farms. Those studies that have been carried out frequently focus on specific aspects of animal welfare, mostly health issues. The aim of the present study, therefore, was to investigate the effects of the farming system on the welfare of dairy cows in a more holistic way. Although this study was carried out in just two federal states of Germany, the results could serve as a suitable model for the whole country. We used the Welfare Quality assessment protocol to measure welfare for dairy cattle (Welfare Quality®, 2009) and the results showed significant differences (P < 0.05) between organic and conventional farms, but there was also considerable variance between individual farms of the same farming system. Organic farms scored higher in all four Welfare Quality® principles: "Good Feeding", "Good Housing", "Good Health" and "Appropriate Behavior" compared to conventional farms. In particular, organic farms obtained higher scores with respect to Welfare Quality® measures of resting comfort, which contributes to a lower percentage of lameness; organic farms also implemented less painful methods for disbudding, or indeed carried out no disbudding, and provided access to pasture and outdoor exercise. However, organic farms still have room for improvement, especially with respect to animal health. Therefore, outcome-based specifications should be included in the current (purely action-oriented) European regulation of organic production (EC, 2008; EU, 2018) to safeguard the health-related aspects of animal welfare.

Effective operating room (OR) utilization by performing low-complex surgical procedures during the 2020 corona pandemic

Purpose

The SARS-CoV-2 pandemic has almost stopped all elective surgical treatment throughout the world. As operating room (OR) capacities are reduced everywhere to ensure availability of intensive care capacities, especially low-complex surgical procedures are often postponed. These include totally implantable central-venous access ports which are important for the oncologic treatment of cancer patients.

Methods

In our study, we investigated the potential of an outpatient surgical centre (OSC) in terms of workflow effectiveness compared to the central operating room complex (COR) of a university hospital using low-complex surgical procedures as an example. Data of 524 consecutive patients who received a Port-a-cath procedure (422 implantations (80.5%) and 102 explantations (19.5%)) in our department between February 2019 and February 2020 were evaluated.

Results

A total of 277 patients were operated in outpatient surgical centre (OSC), and 247 patients received the procedure in the central OR (COR) complex. Grade II and III complications according to the Clavien–Dindo classification occurred in 5.2% (OSC) and 7.3% (COR) of patients. Incision-to-suture time was significantly quicker in the OSC group (36 vs. 42 min., p < 0.032). Total OR time (01:08 vs. 01:20 h) and preparation-to-incision time were also shorter in the OSC group (12 vs. 17 min., p < 0.002).

Conclusion

In order to ensure effective OR utilization especially in times of the corona pandemic, the use of smaller decentralized OR units, e.g., outpatient surgical centres, for performing low-complex surgical cases is beneficial. Our study revealed shorter total OR and preparation-to-incision times.

Time Refraction of Spin Waves

We present an experimental study of time refraction of spin waves (SWs) propagating in microscopic waveguides under the influence of time-varying magnetic fields. Using space- and time-resolved Brillouin light scattering microscopy, we demonstrate that the broken translational symmetry along the time coordinate results in a loss of energy conservation for SWs and thus allows for a broadband and controllable shift of the SW frequency. With an integrated design of SW waveguide and microscopic current line for the generation of strong, nanosecond-long, magnetic field pulses, a conversion efficiency up to 39% of the carrier SW frequency is achieved, significantly larger compared to photonic systems. Given the strength of the magnetic field pulses and its strong impact on the SW dispersion relation, the effect of time refraction can be quantified on a length scale comparable to the SW wavelength. Furthermore, we utilize time refraction to excite SW bursts with pulse durations in the nanosecond range and a frequency shift depending on the pulse polarity.

Melanoma cells can be eliminated by sialylated CD43 × CD3 bispecific T cell engager formats in vitro and in vivo

Targeted cancer therapy with monoclonal antibodies has proven successful for different cancer types but is limited by the availability of suitable antibody targets. CD43s, a unique sialylated form of CD43 expressed by hematologic malignancies, is a recently identified target and antibodies interacting with CD43s may have therapeutic potential against acute myeloid leukemia (AML) and myelodysplastic syndrome. CD43s is recognized by the human antibody AT1413, that was derived from a high-risk AML patient who successfully cleared leukemia after allogeneic stem cell transplantation. Here we observed that AT1413 binds also to certain non-hematopoietic tumor cells, particularly melanoma and breast cancer. AT1413 immune precipitated CD43s from melanoma cells confirming that it recognizes the same target on melanoma as on AML. AT1413 induced antibody-dependent cellular cytotoxicity against short-term cultured patient-derived melanoma samples. However, AT1413 was unable to affect the growth of melanoma cells in vivo. To increase the efficacy of AT1413 as a therapeutic antibody, we generated two different formats of bispecific T-cell engaging antibodies (TCEs): one binding bivalently (bTCE) and the other monovalently (knob-in-hole; KiH) to both CD43s and CD3ε. In vitro, these TCEs redirected T-cell cytotoxicity against melanoma cells with differences in potencies. To investigate their effects in vivo, we grafted mice that harbor a human immune system with the melanoma cell line A375. Treatment with both AT1413 bTCE and AT1413 KiH significantly reduced tumor outgrowth in these mice. These data indicate a broad therapeutic potential of AT1413 that includes AML and CD43s-expressing solid tumors that originate from CD43-negative tissues.

Flashbulb memory recall in healthy adults - a functional magnetic resonance imaging study

The present study investigated neural activations related to flashbulb memory (FM) recall and examined whether the amygdala and hippocampus are involved in FM recall. 20 healthy adults completed a block design with an FM-condition, where the reception events for a number of potential FM events had to be recalled, and a control condition (FMC) comprising reception events lacking FM characteristics. A definition naming task was used as an implicit baseline. The individual emotional reaction to the FM events (EMO) and self-rated retrieval success were included in the SPM model as modulating parameters. The main contrast of interest were FM > FMC and activations associated with EMO. ROI-analyses on mesiotemporal regions were performed. FM > FMC yielded activations in line with the autobiographical memory network, with mostly left sided-activations. EMO was associated with a more bilateral activation pattern. ROI-analysis revealed activations for EMO in the right amygdala and HATA. FM > FMC was associated with right hippocampal activations. The present findings are compatible with previous research into autobiographical memory, but also show activations for FM recall different from ordinary, not highly emotional autobiographical memories, as EMO is associated with a more bilateral network. Moreover, the amygdala seems to be involved in FM recall.

Productivity, Machinery and Skills in a Sample of British and German Manufacturing Plants

On the basis of interviews with management and factory floor employees at 45 matched firms in Britain and West Germany, this article examines the roles of machinery and workforce skills in explaining comparative produc tivity performance. The average age of British machinery was not very different from that found in German plants, but it was less technically advanced, was subject to more frequent breakdowns and breakdowns took longer to correct. Productivity was higher in Germany in each of our matched product groups and the importance of skills at all levels was apparent.

Temperature dependence of germination and growth in Anthurium (Araceae)

By the year 2100, temperatures are predicted to increase by about 6 °C at higher latitudes and about 3 °C in the tropics. In spite of the smaller increase in the tropics, consequences may be more severe because the climatic niches of tropical species are generally assumed to be rather narrow due to a high degree of climate stability and higher niche specialisation. However, rigorous data to back up this notion are rare. We chose the megadiverse genus Anthurium (Araceae) for study. Considering that the regeneration niche of a species is crucial for overall niche breadth, we focused on the response of germination and early growth through a temperature range of 24 °C of 15 Anthurium species, and compared the thermal niche breadth (TNB) with the temperature conditions in their current range, modelled from occurrence records. Surprisingly, an increase of 3 °C would lead to a larger overlap of TNB of germination and modelled in situ temperature conditions, while the overlap of TNB of growth with in situ conditions under current and future conditions is statistically indistinguishable. We conclude that future temperatures tend to be closer to the thermal optima of most species. Whether this really leads to an increase in performance depends on other abiotic and biotic factors, most prominently potentially changing precipitation patterns.

Liquid Chromatographic Method to Determine Narasin in Feedingstuffs and Premixtures: Development, Validation, and Interlaboratory Study

A reversed-phase liquid chromatography (LC) method for narasin in feedingstuffs and premixtures was developed, validated, and interlaboratory studied. The extraction solvent was methanol–K2HPO4 solution (9 + 1, v/v). Narasin was detected at 600 nm after post-column derivatization with dimethylamino-benzaldehyde. Recovery was &gt;90%. The repeatability (RSDr) in feed (20–140 mg/kg) ranged between 1.2 and 10.5%; the within-laboratory reproducibility (RSDR) ranged between 2.2 and 4.9%. The limit of determination was &lt;20 mg/kg. Other feed additives did not interfere in the assay. The method showed ruggedness against changes in the composition of extraction solvent, eluent, and conditions for post-column reactions. In an interlaboratory study, 5 broiler feeds (4 positive, 1 blank) and 1 premixture were analyzed by 13 laboratories. The RSDr of the feedingstuffs (20–120 mg/kg) varied between 2.17 and 7.57%. The HORRAT ranged between 0.77 and 0.88, with recoveries between 82 and 104%. One laboratory detected small signals in the blank sample, calculated as 0.6 and 2.8 mg/kg. For the premixture, acceptable results for reproducibility could only be obtained after modification of the method: the RSDr was 4.42% and the HORRAT was 1.56 (12 laboratories).

Polyacrylamide Bead Sensors for in vivo Quantification of Cell-Scale Stress in Zebrafish Development

Mechanical stress exerted and experienced by cells during tissue morphogenesis and organ formation plays an important role in embryonic development. While techniques to quantify mechanical stresses in vitro are available, few methods exist for studying stresses in living organisms. Here, we describe and characterize cell-like polyacrylamide (PAAm) bead sensors with well-defined elastic properties and size for in vivo quantification of cell-scale stresses. The beads were injected into developing zebrafish embryos and their deformations were computationally analyzed to delineate spatio-temporal local acting stresses. With this computational analysis-based cell-scale stress sensing (COMPAX) we are able to detect pulsatile pressure propagation in the developing neural rod potentially originating from polarized midline cell divisions and continuous tissue flow. COMPAX is expected to provide novel spatio-temporal insight into developmental processes at the local tissue level and to facilitate quantitative investigation and a better understanding of morphogenetic processes.

Billed and Paid Amounts for Preventive Procedures in Dental Medicaid

OBJECTIVE

To examine trends and variations in billed and paid amounts for preventive dental procedures by race/ethnicity, age, and sex in Wisconsin dental Medicaid.

METHODS

We analyzed data from the 2001 to 2013 Wisconsin Medicaid claims database for preventive dental procedures for children and adults. Billed and paid amounts for preventive dental procedures were aggregated over a visit and adjusted for inflation based on the Medical Care Consumer Price Index produced by the Bureau of Labor Statistics for 2013. Quantile regression was used to examine the trends over time and the effect of patient demographics.

RESULT

At the 50th and 75th percentiles, the overall billed amounts for preventive dental procedures were $84.97 and $105.53, and the paid amounts were $35.80 and $41.66, respectively. At the 75th percentile, there was a $2.24 increase per year in the billed amount and a $26.88 overall increase from 2001 to 2013. In the paid amount, there was a $1.34 decrease per year for an overall $16.07 decrease from 2001 to 2013. Billed and paid claims for racial/ethnic minority enrollees were $1 to $3 higher per visit at the 75th percentile when compared with those of Whites. Regarding the billed:paid ratio, White, African American, and Hispanic enrollees had values of 50% to 52%, whereas American Indians had the lowest value at 47.7%. At the 75th percentile, children aged 10 to 19 y had significantly higher billed ($26.73) and paid ($9.92) amounts than did adults aged 20 to 69 y.

CONCLUSION

The billed amount increased over time, and the paid amount decreased after adjustment for inflation. In addition, there was a wide gap between billed and paid amounts over time.

KNOWLEDGE TRANSFER STATEMENT

This study highlights clear differences between paid and billed amounts in Wisconsin dental Medicaid. The financial health of dental practices is dependent on appropriate reimbursement for dental services provided; thus, information of this nature could serve as a proxy performance measure for access to preventive dental care. Findings from this study could be used by policy makers and dental Medicaid program managers to develop outcome metrics to improve access to preventive dental services.

A giant exoplanet orbiting a very-low-mass star challenges planet formation models

Surveys have shown that super-Earth and Neptune-mass exoplanets are more frequent than gas giants around low-mass stars, as predicted by the core accretion theory of planet formation. We report the discovery of a giant planet around the very-low-mass star GJ 3512, as determined by optical and near-infrared radial-velocity observations. The planet has a minimum mass of 0.46 Jupiter masses, very high for such a small host star, and an eccentric 204-day orbit. Dynamical models show that the high eccentricity is most likely due to planet-planet interactions. We use simulations to demonstrate that the GJ 3512 planetary system challenges generally accepted formation theories, and that it puts constraints on the planet accretion and migration rates. Disk instabilities may be more efficient in forming planets than previously thought.

Excitation of Whispering Gallery Magnons in a Magnetic Vortex

We present the generation of whispering gallery magnons with unprecedented high wave vectors via nonlinear 3-magnon scattering in a μm-sized magnetic Ni_{81}Fe_{19} disc which is in the vortex state. These modes exhibit a strong localization at the perimeter of the disc and practically zero amplitude in an extended area around the vortex core. They originate from the splitting of the fundamental radial magnon modes, which can be resonantly excited in a vortex texture by an out-of-plane microwave field. We shed light on the basics of this nonlinear scattering mechanism from an experimental and theoretical point of view. Using Brillouin light scattering microscopy, we investigated the frequency and power dependence of the 3-magnon splitting. The spatially resolved mode profiles give evidence for the localization at the boundaries of the disc and allow for a direct determination of the modes wave number.

Abstract PD5-05: Pre-therapeutic PD-L1 expression and dynamics of Ki-67 and gene expression during neoadjuvant immune-checkpoint blockade and chemotherapy to predict response within the GeparNuevo trial

Background

In the GeparNuevo trial, the PD-L1 inhibitor durvalumab increased the rate of pathologic complete response (pCR; ypT0 ypN0) in triple-negative breast cancer if treatment started in a two-week window before neoadjuvant taxane/anthracycline chemotherapy (61 % pCR vs. 41%; p = 0.048; Loibl et al. ASCO 2018). Overall, pCR rates increased only numerically from 53 % to 44 % (p = 0.281). Herein, we aimed to evaluate the predictive value of PD-L1 immunohistochemistry in pre-therapeutic core biopsies. In addition, we identified dynamics in gene expression using repeated biopsies.

Patients and Methods

174 patients were randomized to receive durvalumab or placebo with neoadjuvant chemotherapy. In the window part, 117 patients received a single dose of durvalumab (or placebo) before chemotherapy. Core biopsies were taken at three times: pre-treatment (“A”; N=174), after the window part (“B”; N=88) and after 12 weeks of nab-Paclitaxel (“C”; N=33). PD-L1 immunohistochemistry in A-biopsies (Ventana SP263 Assay) was recorded as percentage of cells with membranous staining in tumor cells and lymphocytes (TILs). We defined a tumor as PD-L1 high if ≥ 25 % of either compartment was stained. Ki-67 was stained on all available A, B and C biopsies (MIB-1, Dako, 1:100) and recorded as the percentage of tumor cells with nuclear staining. We profiled all available biopsies with targeted RNASeq using the HTG EdgeSeq platform (Oncology Biomarker panel, 2560 genes). Sequencing (IonTorrent S5) was successful in 162 A-, 79 B- and 31 C-biopsies.

Results

PD-L1 expression was high in 24 % of A-biopsies and was predictive for pCR in the complete cohort (OR 2.561; 1.183-5.554; p = 0.017). PD-L1 status of the TILs, but not of the tumor cells, was predictive (OR 1.313; 1.040-1.656; P= 0.022). The effect was not specific for durvalumab treatment. Higher levels of Ki-67 were predictive for pCR in B- biopsies in all patients (OR 1.399; 1.053-1.858; P =0.021) and in the placebo arm, but not in the durvalumab arm. Ki-67 levels in C-biopsies were not predictive; neither was the change in Ki-67 between pre-treatment and later time points (B vs. A or C vs. A).

In a differential mRNA expression analysis (A vs. B), we found seven differentially expressed genes after one dose of durvalumab. We observed strong effects on gene expression after taxane treatment (A vs. C), but no significant difference according to treatment. These genes were associated with biological processes involved in therapy response. The pre-treatment levels of 12 of 69 markedly differentially expressed genes were associated with worse response to chemotherapy.

Conclusion

In A-biopsies, PD-L1 in TILs was predictive for response, and in B-biopsies, Ki-67 was predictive, but neither marker could specifically predict response to durvalumab. We observed limited effects of a single half-dose of durvalumab on global gene expression, but could identify substantial differential expression after taxane treatment. The evaluation of gene expression dynamic offers a promising approach for the identification of resistance-associated markers.

The study was financially supported by AstraZeneca and Celgene

Citation Format: Sinn BV, Loibl S, Karn T, Untch M, Kunze CA, Weber KE, Treue D, Wagner K, Hanusch CA, Klauschen F, Fasching PA, Huober J, Zahm D-M, Jackisch C, Thomalla J, Blohmer J-U, van Mackelenbergh M, Rhiem K, Felder B, von Minckwitz G, Burchardi N, Schneeweiss A, Denkert C. Pre-therapeutic PD-L1 expression and dynamics of Ki-67 and gene expression during neoadjuvant immune-checkpoint blockade and chemotherapy to predict response within the GeparNuevo trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD5-05.

Evaluation of Lightmix Mycoplasma macrolide assay for detection of macrolide-resistant Mycoplasma pneumoniae in pneumonia patients

OBJECTIVES

Rapid detection of macrolide resistance-associated mutations in Mycoplasma pneumoniae is crucial for effective antimicrobial treatment. We evaluated the Lightmix Mycoplasma macrolide assay for the detection of point mutations at nucleotide positions 2063 and 2064 in the 23S ribosomal RNA (rRNA) gene of M. pneumoniae that confer macrolide resistance.

METHODS

Samples from 3438 patients with a respiratory tract infection were analysed by M. pneumoniae real-time PCR, and 208 (6%) of them were tested positive. In this retrospective study, 163 M. pneumoniae real-time PCR-positive samples were analysed by the Lightmix assay, and results were compared to targeted 23S rRNA sequencing.

RESULTS

Macrolide-resistant M. pneumoniae were found in 15 (9%) of 163 retrospectively analysed samples. The Lightmix assay showed a sensitivity of 100% (95% confidence interval, 78.2-100) and a specificity of 100% (95% confidence interval, 97.5-100) as the detected M. pneumoniae genotype (148 wild type and 15 non-wild type) was confirmed by 23S rRNA sequencing in all samples.

CONCLUSIONS

The Lightmix assay is an easy-to-use and accurate molecular test that allows rapid determination of macrolide resistance in M. pneumoniae.

Standardized microgel beads as elastic cell mechanical probes

Cell mechanical measurements are gaining increasing interest in biological and biomedical studies. However, there are no standardized calibration particles available that permit the cross-comparison of different measurement techniques operating at different stresses and time-scales. Here we present the rational design, production, and comprehensive characterization of poly-acrylamide (PAAm) microgel beads mimicking size and overall mechanics of biological cells. We produced mono-disperse beads at rates of 20-60 kHz by means of a microfluidic droplet generator, where the pre-gel composition was adjusted to tune the beads' elasticity in the range of cell and tissue relevant mechanical properties. We verified bead homogeneity by optical diffraction tomography and Brillouin microscopy. Consistent elastic behavior of microgel beads at different shear rates was confirmed by AFM-enabled nanoindentation and real-time deformability cytometry (RT-DC). The remaining inherent variability in elastic modulus was rationalized using polymer theory and effectively reduced by sorting based on forward-scattering using conventional flow cytometry. Our results show that PAAm microgel beads can be standardized as mechanical probes, to serve not only for validation and calibration of cell mechanical measurements, but also as cell-scale stress sensors.

Molecular detection of fungal pathogens in clinical specimens by 18S rDNA high-throughput screening in comparison to ITS PCR and culture

The rising incidence of invasive fungal infections and the expanding spectrum of fungal pathogens makes early and accurate identification of the causative pathogen a daunting task. Diagnostics using molecular markers enable rapid identification of fungi, offer new insights into infectious disease dynamics, and open new possibilities for infectious disease control and prevention. We performed a retrospective study using clinical specimens (N = 233) from patients with suspected fungal infection previously subjected to culture and/or internal transcribed spacer (ITS) PCR. We used these specimens to evaluate a high-throughput screening method for fungal detection using automated DNA extraction (QIASymphony), fungal ribosomal small subunit (18S) rDNA RT-PCR and amplicon sequencing. Fungal sequences were compared with sequences from the curated, commercially available SmartGene IDNS database for pathogen identification. Concordance between 18S rDNA RT-PCR and culture results was 91%, and congruence between 18S rDNA RT-PCR and ITS PCR results was 94%. In addition, 18S rDNA RT-PCR and Sanger sequencing detected fungal pathogens in culture negative (N = 13) and ITS PCR negative specimens (N = 12) from patients with a clinically confirmed fungal infection. Our results support the use of the 18S rDNA RT-PCR diagnostic workflow for rapid and accurate identification of fungal pathogens in clinical specimens.

Muscular and cardiac manifestations in a Duchenne-carrier harboring a dystrophin deletion of exons 12-29

Female carriers of mutations in the dystrophin gene (DMD-carriers) may manifest clinically in the skeletal muscle, the heart, or both. Cardiac involvement may manifest before, after, or together with the muscle manifestations. A 46y female developed slowly progressive weakness of the lower and upper limbs with left-sided predominance since age 26y. Muscle enzymes were repeatedly elevated and muscle biopsy showed absence of dystrophin. MLPA analysis revealed a deletion of exons 12-29. After starting steroids at age 39y, she developed palpitations and exertional dyspnoea. Cardiac MRI at age 41y revealed mildly reduced systolic function, a slightly enlarged left ventricle, mild hypokinesia of the entire myocardium, and focal, transmural late gadolinium enhancement (LGE) of the midventricular lateral wall. She did not tolerate beta-blockers but profited from ivabradine and lisinopril. In conclusion, muscle manifestations in DMD-carriers with deletions of exons 12-29 may start years before cardiac involvement becomes clinically apparent. Progressive worsening of systolic function in DMD-carriers is attributable to progressive myocardial fibrosis, as demonstrated by LGE. Steroids may trigger the development of cardiac disease in DMD-carriers.

Epiphytic bromeliads in a changing world: the effect of elevated CO2 and varying water supply on growth and nutrient relations

Global climate change is likely to impact all plant life. Vascular epiphytes represent a life form that may be affected more than any other by possible changes in precipitation leading to water shortage, but negative effects of drought may be mitigated through increasing levels of atmospheric CO₂ . We studied the response of three epiphytic Aechmea species to different CO₂ and watering levels in a full-factorial climate chamber study over 100 days. All species use crassulacean acid metabolism (CAM). Response variables were relative growth rate (RGR), nocturnal acidification and foliar nutrient levels (N, P, K, Mg). Both elevated CO₂ and increased water supply stimulated RGR, but the interaction of the two factors was not significant. Nocturnal acidification was not affected by these factors, indicating that the increase in growth in these CAM species was due to higher assimilation in the light. Mass-based foliar nutrient contents were consistently lower under elevated CO₂ , but most differences disappeared when expressed on an area basis. Compared to previous studies with epiphytes, in which doubling of CO₂ increased RGR, on average, by only 14%, these Aechmea species showed a relatively strong growth stimulation of up to +61%. Consistent with earlier findings with other bromeliads, elevated CO₂ did not mitigate the effect of water shortage.

Effect of Dialyzer Membranes on in Vitro Generation of Eicosanoids

Eicosanoids are potent substances released from blood cells after contact with foreign materials. Eicosanoid generation, in addition to complement fragment formation, may be a valuable indicator of the biocompatibility of dialyzer membranes. In the present in vitro study, eicosanoid generation induced by several different flat dialyzer membranes [polyacrylonitrile (PAN), cuprammonium cellulose (CC), and polycarbonate (PC)] was evaluated and compared using blood from non-uremic healthy volunteers.

Generation of prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) was greatest with PC followed by PAN and CC. The formation of C3a des arg with PAN was less than with either CC or PC.

Our results suggest that dialyzer membranes affect complement activation and eicosanoid generation differently; biocompatibility as expressed by a low level of complement fragment formation does not necessarily translate into biocompatibility when considering eicosanoid generation.