Universität Bern
  • Bern, Switzerland
Recent publications
Plasmodium sporozoite development in and egress from oocysts in the Anopheles mosquito remains largely enigmatic. In a previously performed high‐throughput knockout screen, the putative subunit 5 of the prefoldin complex (PbPCS5, PBANKA_0920100) was identified as essential for parasite development during mosquito and liver stage development. Here we generated and analyzed a PbPCS5 knockout parasite line during its development in the mosquito. Interestingly, PbPCS5 deletion does not significantly affect oocyst formation but leads to a growth defect resulting in aberrantly shaped sporozoites. Sporozoites produced in the absence of PbPCS5 were thinner, markedly elongated, and did, in most cases, not contain a nucleus. Sporozoites contained fewer subpellicular microtubules, which reached deep into the sporoblast during sporogony where they contacted and indented nuclei. These aberrantly shaped sporozoites did not reach the salivary glands, and we, therefore, conclude that PbPCS5 is essential for sporogony and the life cycle progression of the parasite during its mosquito stage.
Objective: To evaluate the potential of a novel synthetic carbonate apatite bone substitute (CO3 Ap-BS) on periodontal regeneration. Background: The use of various synthetic bone substitutes as a monotherapy for periodontal regeneration mainly results in a reparative healing pattern. Since xenografts or allografts are not always accepted by patients for various reasons, a synthetic alternative would be desirable. Methods: Acute-type 3-wall intrabony defects were surgically created in 4 female beagle dogs. Defects were randomly allocated and filled with CO3 Ap-BS (test) and deproteinized bovine bone mineral (DBBM) or left empty (control). After 8 weeks, the retrieved specimens were scanned by micro-CT, and the percentages of new bone, bone substitute, and soft tissues were evaluated. Thereafter, the tissues were histologically and histometrically analyzed. Results: Healing was uneventful in all animals, and defects were present without any signs of adverse events. Formation of periodontal ligament and cementum occurred to varying extent in all groups without statistically significant differences between the groups. Residues of both bone substitutes were still present and showed integration into new bone. Histometry and micro-CT revealed that the total mineralized area or volume was higher with the use of CO3 Ap-BS compared to control (66.06 ± 9.34%, 36.11 ± 6.40%; p = .014, or 69.74 ± 2.95%, 42.68 ± 8.68%; p = .014). The percentage of bone substitute surface covered by new bone was higher for CO3 Ap-BS (47.22 ± 3.96%) than for DBBM (16.69 ± 5.66, p = .114). Conclusions: CO3 Ap-BS and DBBM demonstrated similar effects on periodontal regeneration. However, away from the root surface, more new bone, total mineralized area/volume, and higher osteoconductivity were observed for the CO3 Ap-BS group compared to the DBBM group. These findings point to the potential of CO3 Ap-BS for periodontal and bone regeneration.
Rising antimicrobial resistance (AMR) and lack of innovation in the antibiotic pipeline necessitate novel approaches to discovering new drugs. Metal complexes have proven to be promising antimicrobial compounds, but the number of studied compounds is still low compared to the millions of organic molecules investigated so far. Lately, machine learning (ML) has emerged as a valuable tool for guiding the design of small organic molecules, potentially even in low-data scenarios. For the first time, we extend the application of ML to the discovery of metal-based medicines. Utilising 288 modularly synthesized ruthenium arene Schiff-base complexes and their antibacterial properties, a series of ML models were trained. The models perform well and are used to predict the activity of 54 new compounds. These displayed a 5.7x higher hit-rate (53.7%) against methicillin-resistant Staphylococcus aureus (MRSA) compared to the original library (9.4%), demonstrating that ML can be applied to improve the success-rates in the search of new metalloantibiotics. This work paves the way for more ambitious applications of ML in the field of metal-based drug discovery.
Genomic diversity is associated with the adaptive potential of a population and thereby impacts the extinction risk of a species during environmental change. However, empirical data on genomic diversity of populations before environmental perturbations are rare and hence our understanding of the impact of perturbation on diversity is often limited. We here assess genomic diversity utilising whole‐genome resequencing data from all four species of the Lake Constance Alpine whitefish radiation. Our data covers a period of strong but transient anthropogenic environmental change and permits us to track changes in genomic diversity in all species over time. Genomic diversity became strongly reduced during the period of anthropogenic disturbance and has not recovered yet. The decrease in genomic diversity varies between 18% and 30%, depending on the species. Interspecific allele frequency differences of SNPs located in potentially ecologically relevant genes were homogenized over time. This suggests that in addition to the reduction of genome‐wide genetic variation, the differentiation that evolved in the process of adaptation to alternative ecologies between species might have been lost during the ecological disturbance. The erosion of substantial amounts of genomic variation within just a few generations in combination with the loss of potentially adaptive genomic differentiation, both of which had evolved over thousands of years, demonstrates the sensitivity of biodiversity in evolutionary young adaptive radiations towards environmental disturbance. Natural history collections, such as the one used for this study, are instrumental in the assessment of genomic consequences of anthropogenic environmental change. Historical samples enable us to document biodiversity loss against the shifting baseline syndrome and advance our understanding of the need for efficient biodiversity conservation on a global scale.
Introduction Distinguishing phenotypes among children with cough helps understand underlying causes. Using a statistical data‐driven approach, we aimed to identify and validate cough phenotypes based on measurable traits, physician diagnoses, and prognosis. Methods We used data from the Swiss Paediatric Airway Cohort and included 531 children aged 5–16 years seen in outpatient clinics since 2017. We included children with any parent‐reported cough (i.e. cough without a cold, cough at night, cough more than other children, or cough longer than 4 weeks) without current wheeze. We applied latent class analysis to identify phenotypes using nine symptoms and characteristics and selected the best model using the Akaike information criterion. We assigned children to the most likely phenotype and compared the resulting groups for parental atopy history, comorbidities, spirometry, fractional exhaled nitric oxide (FeNO), skin prick tests and specific IgE, physician diagnoses, and 1‐year prognosis. Results We identified four cough phenotypes: non‐specific cough (26%); non‐allergic infectious and night cough with snoring and otitis (4%); chronic allergic dry night cough with snoring (9%); and allergic non‐infectious cough with rhino‐conjunctivitis (61%). Children with the allergic phenotype often had family or personal history of atopy and asthma diagnosis. FeNO was highest for the allergic phenotype [median 17.9 parts per billion (ppb)] and lowest for the non‐allergic infectious phenotype [median 7.0 parts per billion (ppb)]. Positive allergy test results differed across phenotypes ( p < .001) and were most common among the allergic (70%) and least common among the non‐specific cough (31%) phenotypes. Subsequent wheeze was more common among the allergic than the non‐specific phenotype. Conclusion We identified four clinically relevant cough phenotypes with different prognoses. Although we excluded children with current wheeze, most children with cough belonged to allergy‐related phenotypes.
Importance Abbreviated dual antiplatelet therapy (DAPT) reduces bleeding with no increase in ischemic events in patients at high bleeding risk (HBR) undergoing percutaneous coronary intervention (PCI). Objectives To evaluate the association of sex with the comparative effectiveness of abbreviated vs standard DAPT in patients with HBR. Design, Setting, and Patients This prespecified subgroup comparative effectiveness analysis followed the Management of High Bleeding Risk Patients Post Bioresorbable Polymer Coated Stent Implantation With an Abbreviated vs Standard DAPT Regimen (MASTER DAPT) trial, a multicenter, randomized, open-label clinical trial conducted at 140 sites in 30 countries and performed from February 28, 2017, to December 5, 2019. A total of 4579 patients with HBR were randomized at 1 month after PCI to abbreviated or standard DAPT. Data were analyzed from July 1 to October 31, 2022. Interventions Abbreviated (immediate DAPT discontinuation, followed by single APT for ≥6 months) or standard (DAPT for ≥2 additional months, followed by single APT for 11 months) treatment groups. Main Outcomes and Measures One-year net adverse clinical events (NACEs) (a composite of death due to any cause, myocardial infarction, stroke, or major bleeding), major adverse cardiac or cerebral events (MACCEs) (a composite of death due to any cause, myocardial infarction, or stroke), and major or clinically relevant nonmajor bleeding (MCB). Results Of the 4579 patients included in the analysis, 1408 (30.7%) were women and 3171 (69.3%) were men (mean [SD] age, 76.0 [8.7] years). Ischemic and bleeding events were similar between sexes. Abbreviated DAPT was associated with comparable NACE rates in men (hazard ratio [HR], 0.97 [95% CI, 0.75-1.24]) and women (HR, 0.87 [95% CI, 0.60-1.26]; P = .65 for interaction). There was evidence of heterogeneity of treatment effect by sex for MACCEs, with a trend toward benefit in women (HR, 0.68 [95% CI, 0.44-1.05]) but not in men (HR, 1.17 [95% CI, 0.88-1.55]; P = .04 for interaction). There was no significant interaction for MCB across sex, although the benefit with abbreviated DAPT was relatively greater in men (HR, 0.65 [95% CI, 0.50-0.84]) than in women (HR, 0.77 [95% CI, 0.53-1.12]; P = .46 for interaction). Results remained consistent in patients with acute coronary syndrome and/or complex PCI. Conclusions and Relevance These findings suggest that women with HBR did not experience higher rates of ischemic or bleeding events compared with men and may derive particular benefit from abbreviated compared with standard DAPT owing to these numerically lower rates of events. Trial Registration ClinicalTrials.gov Identifier: NCT03023020
Background Amyloid A (AA) amyloidosis is a protein misfolding disease arising from serum amyloid A (SAA). Systemic AA amyloidosis recently was shown to have a high prevalence in shelter cats in Italy and was associated with azotemia and proteinuria. Objectives Investigate urine protein profiles and diagnostic biomarkers in cats with renal AA amyloidosis. Animals Twenty‐nine shelter cats. Methods Case‐control study. Cats with renal proteinuria that died or were euthanized between 2018 and 2021 with available necropsy kidney, liver and spleen samples, and with surplus urine collected within 30 days before death, were included. Histology was used to characterize renal damage and amyloid amount and distribution; immunohistochemistry was used to confirm AA amyloidosis. Urine protein‐to‐creatinine (UPC) and urine amyloid A‐to‐creatinine (UAAC) ratios were calculated, and sodium dodecyl sulfate‐agarose gel electrophoresis (SDS‐AGE) and liquid chromatography‐mass spectrometry (LC‐MS) of proteins were performed. Results Twenty‐nine cats were included. Nineteen had AA amyloidosis with renal involvement. Cats with AA amyloidosis had a higher UPC (median, 3.9; range, 0.6‐12.7 vs 1.5; 0.6‐3.1; P = .03) and UAAC ratios (median, 7.18 × 10 ⁻³ ; range, 23 × 10 ⁻³ ‐21.29 × 10 ⁻³ vs 1.26 × 10 ⁻³ ; 0.21 × 10 ⁻³ ‐6.33 × 10 ⁻³ ; P = .04) than unaffected cats. The SDS‐AGE identified mixed‐type proteinuria in 89.4% of cats with AA amyloidosis and in 55.6% without AA amyloidosis ( P = .57). The LC‐MS identified 63 potential biomarkers associated with AA amyloidosis ( P < .05). Among these, urine apolipoprotein C‐III was higher in cats with AA amyloidosis (median, 1.38 × 10 ⁷ ; range, 1.85 × 10 ⁵ ‐5.29 × 10 ⁷ vs 1.76 × 10 ⁶ ; 0.0 × 10 ⁰ ‐1.38 × 10 ⁷ ; P = .01). In the kidney, AA‐amyloidosis was associated with glomerulosclerosis ( P = .02) and interstitial fibrosis ( P = .05). Conclusions and Clinical Importance Renal AA amyloidosis is associated with kidney lesions, increased proteinuria and increased urine excretion of SAA in shelter cats. Additional studies are needed to characterize the role of lipid transport proteins in the urine of affected cats.
Plain Language Summary Volcanic eruptions can influence global climate through the emission of sulfuric acids shielding Earth from incoming solar radiation. Previous volcanic reconstructions based on ice‐cores from the polar regions, however, only considered very strong volcanic eruptions. In this study, based on new ice‐core measurements from Greenland, we reconstruct for the first time volcanic sulfur emissions from small to medium‐sized eruptions and investigate their impact on climate in the early 19th century through experiments with the Max Planck Institute Earth System Model (MPI‐ESM1.2‐LR). We find that clustering of small to medium‐sized eruptions can cause significant global surface cooling (∼0.07 K), which during the 1812–1820 period amplified the cooling caused by the two known large eruptions of the period (1809 unidentified and 1815 Tambora). This additional surface cooling from small eruptions helps explain the long‐lasting cooling after the two strong eruptions generally found in the reconstruction, but the simulated regional impacts cannot be fully confirmed with reconstructions that are too noisy. This study highlights the importance of including small‐to‐moderate eruptions for climate model simulations as their impacts are comparable with that of solar irradiance forcing.
The Swiss Digital Pathology Consortium (SDiPath) was founded in 2018 as a working group of the Swiss Society for Pathology with the aim of networking, training, and promoting digital pathology (DP) at a national level. Since then, two national surveys have been carried out on the level of knowledge, dissemination, use, and needs in DP, which have resulted in clear fields of action. In addition to organizing symposia and workshops, national guidelines were drawn up and an initiative for a national DP platform actively codesigned. With the growing use of digital image processing and artificial intelligence tools, continuous monitoring, evaluation, and exchange of experiences will be pursued, along with best practices.
Cell-free biocatalysis is gaining momentum in the production of value-added chemicals, particularly in stepwise reaction cascades. However, the stability of enzyme cascades in industrial settings is often compromised when using free enzymes. In this study, we have developed a stable multifunctional heterogeneous biocatalyst co-immobilizing five enzymes on microparticles to transform 1,ω-diols into 1,ω-hydroxy acids. We improved the operational efficiency and stability of the heterogeneous biocatalyst by fine-tuning enzyme loading and spatial organization. Stability issues are overcome through post-immoblization polymer coating. The general applicability of this heterogeneous biocatalyst is demonstrated by its scale-up in both batch and packed bed reactors, allowing a product yield > 80%. The continuous process is fed with H 2 O 2 as oxygen source, reaching a Space-Time Yield (STY) of 0.76 g·L − 1 ·h − 1 , maintained for the first 12 hours. Finally, this flow system is telescoped with a second plug-flow reactor packed with a different heterogeneous biocatalyst. As a result, this 6-enzyme 2-reactor system sequentially transforms 1,ω-diols into 1,ω-aminoacids while in-situ recycling NAD ⁺ , depleting H 2 O 2 and generating O 2 .
Platelet‐rich fibrin (PRF) has been characterized as a regenerative biomaterial that is fully resorbed within a typical 2–3 week period. Very recently, however, a novel heating process was shown to extend the working properties of PRP/PRF from a standard 2–3 week period toward a duration of 4–6 months. Numerous clinicians have now utilized this extended‐PRF (e‐PRF) membrane as a substitute for collagen barrier membranes in various clinical applications, such as guided tissue/bone regeneration. This review article summarizes the scientific work to date on this novel technology, including its current and future applications in periodontology, implant dentistry, orthopedics and facial aesthetics. A systematic review was conducted investigating key terms including “Bio‐Heat,” “albumin gel,” “albumin‐PRF,” “Alb‐PRF,” “extended‐PRF,” “e‐PRF,” “activated plasma albumin gel,” and “APAG” by searching databases such as MEDLINE, EMBASE and PubMed. Findings from preclinical studies demonstrate that following a simple 10‐min heating process, the transformation of the liquid plasma albumin layer into a gel‐like injectable albumin gel extends the resorption properties to at least 4 months according to ISO standard 10 993 (subcutaneous animal model). Several clinical studies have now demonstrated the use of e‐PRF membranes as a replacement for collagen membranes in GTR/GBR procedures, closing lateral windows in sinus grafting procedures, for extraction site management, and as a stable biological membrane during recession coverage procedures. Furthermore, Alb‐PRF may also be injected as a regenerative biological filler that lasts extended periods with advantages in joint injections, osteoarthritis and in the field of facial aesthetics. This article highlights the marked improvement in the stability and degradation properties of the novel Alb‐PRF/e‐PRF technology with its widespread future potential use as a potential replacement for collagen membranes with indications including extraction site management, GBR procedures, lateral sinus window closure, recession coverage among others, and further highlights its use as a biological regenerative filler for joint injections and facial aesthetics. It is hoped that this review will pioneer future opportunities and research development in the field, leading to further progression toward more natural and less costly biomaterials for use in medicine and dentistry.
Background Atopic dermatitis (AD) is characterized by skin barrier dysfunction and immune dysregulation. Autophagy, which is important for the epidermal differentiation, is impaired in AD. The treatment with dupilumab, an interleukin (IL)‐4/IL‐13 receptor blocker, has been shown to reduce skin inflammation and restore the skin barrier. Objectives This study aimed to investigate the effect of dupilumab on the expression of key proteins involved in autophagy and lysosomal degradation. Methods We performed immunofluorescence staining and microscopic analyses of skin specimens of AD patients, taken before and under (6–10 weeks) therapy with dupilumab, to investigate the expression of autophagy‐related (ATG) 5 and ATG7 proteins, beclin‐1, microtubule‐associated protein light chain 3 (LC3B), sequestosome‐1 (p62), lysosomal proteases (cathepsins B, D and L), serine protease inhibitors (SERPINB3, SERPINB4) as well as IL‐33 and thymic stromal lymphopoietin (TSLP). Results The expression of LC3B and p62 as well as SERPINB3 and SERPINB4 was highly increased in untreated AD skin compared to non‐lesional skin and normal skin and decreased upon dupilumab therapy. In contrast, the AD‐associated increased expression of both ATG5 and ATG7 further increased under therapy. Before therapy, cathepsin D and L expression levels were significantly lower compared to normal skin, but increased following the initiation of dupilumab therapy. The increased expression of IL‐33 and TSLP in the epidermis of AD patients correlated with that of LC3B and p62. Conclusions Our study provides further evidence that autophagy is inhibited in lesional AD skin owing to lysosomal dysfunction. Upon dupilumab therapy, a restoration of dysregulated key players of autophagy is observed.
Depressive disorders are a main cause of disability-adjusted life years already in children and adolescents, in whom the clinical picture somewhat differs from adult-onset depression. Thus, we studied sociodemographic and clinical predictors of depression/dysthymia in a sample of minors. Our baseline sample (N=676) included patients at clinical high-risk for psychosis (CHR-P, n=183), inpatients admitted for non-psychotic, non-affective disorders (n=277), and community participants (n=216) of age 7.0 to 17.9 years (43.8% male). They were assessed by clinical psychologists for mental disorders and symptoms with various clinical interviews including the Mini International Neuropsychiatric Interview for Children and Adolescents, which was also used to assess depression/dysthymia in the CHR-P group at 1- and 2-year-follow up (n=117 and 73, respectively). Analyses followed a stepwise procedure at baseline with stepwise logistic regression analyses to identify the final baseline model that was tested in the follow-up samples. The final cross-sectional model included nationality and 13 clinical variables Mild depressive symptoms in particular played a decisive role here. Variables contributing significantly to the prediction varied over time, indicating that CAD depression/dysthymia may require different predictors depending on the follow-up time. Furthermore, the prospective accuracy of ruling out depression/dysthymia was superior to the accuracy of ruling it in. This lower positive likelihood ratio might be overcome in future by stepwise approaches that further stratify risk in those initially identified as at increased risk of depression/dysthymia.
Background Venous leak appears to be the most common cause of vasculogenic erectile dysfunction (ED), which can be treated with venous embolization. Traditionally, conventional cavernosography was used for the diagnosis and treatment planning of venous leak. Recently, computed tomography (CT) cavernosography was introduced as a novel cross-sectional imaging method proposed to be advantageous over conventional cavernosography. We created a novel management algorithm for diagnosing venous leak including CT cavernosography as an imaging modality. In order to provide a broader basis for our management algorithm, a systematic literature review was conducted. Main body In this article we systematically review relevant literature on using CT cavernosography for the diagnosis and treatment planning in ED patients with venous leak following the PRISMA selection process. Nine full-text articles were included in the review and assigned a level of evidence grade (all grade II). Two studies (2/9) compared the results of conventional cavernosography with those of CT cavernosography which was superior for site-specific venous leak identification (19.4% vs. 100%, respectively). CT cavernosography is a more detailed imaging method that is faster to perform, exposes the patient to less radiation, and requires less contrast material. In one study (1/9), CT cavernosography was used for diagnostic purposes only. Eight studies (8/9) cover both, diagnostic imaging and treatment planning including embolization (1/9) and sclerotherapy (2/9) of venous leak in patients with venogenic ED. Three studies (3/9) describe anatomical venous leak classifications that were established based on CT cavernosography findings for accurate mapping of superficial and/or deep venous leak and identification of mixed or more complex forms of venous leak present in up to 84% of patients. In addition to treatment planning, one study (1/9) used CT cavernosography also for follow-up imaging post treatment. Conclusion CT cavernosography is superior to conventional cavernosography for diagnosis and treatment planning in patients with ED caused by venous leak (grade II levels of evidence). Consequently, CT cavernosography should be included in management algorithms for ED patients with suspected venous leak.
Background Albumin administration is suggested in patients with sepsis and septic shock who have received large volumes of crystalloids. Given lack of firm evidence, clinical practice variation may exist. To address this, we investigated if patient characteristics or trial site were associated with albumin use in septic shock. Methods We conducted a post‐hoc study of the CLASSIC international, randomised clinical trial of fluid volumes in septic shock. Associations between selected baseline variables and trial site with albumin use during ICU stay were assessed in Cox models considering death, ICU discharge, and loss‐to‐follow‐up as competing events. Baseline variables were first assessed individually, adjusted for treatment allocation (restrictive vs. standard IV fluid), and then adjusted for allocation and the other baseline variables. Site was assessed in a model adjusted for allocation and baseline variables. Results We analysed 1541 of 1554 patients randomised in CLASSIC (99.2%). During ICU stay, 36.3% of patients in the restrictive‐fluid group and 52.6% in the standard‐fluid group received albumin. Gastrointestinal focus of infection and higher doses of norepinephrine were most strongly associated with albumin use (subgroup with highest quartile of norepinephrine doses, hazard ratio (HR) 2.58, 95% CI 1.89 to 3.53). HRs for associations between site and albumin use ranged from 0.11 (95% CI 0.05 to 0.26) to 1.70 (95% CI 1.06 to 2.74); test for overall effect of site: p < .001. Conclusions In adults with septic shock, gastrointestinal focus of infection and higher doses of norepinephrine at baseline were associated with albumin use, which also varied substantially between sites.
Shunt-dependent hydrocephalus (HC) is a common sequela following aneurysmal subarachnoid hemorrhage (aSAH). However,there is still poor evidence regarding the optimal timing of ventriculoperitoneal shunt (VPS) placement, particularly in the context of early aSAH-associated complications such as delayed cerebral ischemia (DCI). The purpose of this study was to compare the impact of early (< 21 days after aSAH) versus late (≥ 21 days after aSAH) VPS placement on the functional clinical outcome. We retrospectively analyzed data from 82 patients with VPS placement after aSAH enrolled in our institutional database between 2011 and 2021. We compared two groups, early VPS placement (< 21 days after aSAH) versus late VPS placement (≥ 21 days after aSAH) in terms of demographics, SAH grading, radiological parameters, externalized cerebrospinal fluid diversions, DCI, VPS variables, and functional outcome. We identified 53 patients with early and 29 patients with late VPS implantation. Baseline variables, such as the modified Rankin Scale (mRS), the World Federation of Neurological Surgeons Scale, the Glasgow Coma Scale, and Fisher grade were not significantly different between the groups. Postoperatively, the mRS (p = 0.0037), the Glasgow Outcome Scale (p = 0.0037), and the extended Glasgow Outcome Scale (p = 0.0032) showed significantly better functional results in patients with early cerebrospinal fluid diversion. The rate of DCI did not differ significantly between the groups (p = 0.53). There was no difference in the rate of VPS placement associated complications (p = 0.44) or overall mortality (p = 0.39). Early shunt implantation, within 21 days after aSAH and therefore during the timeframe of possible DCI, might not be harmful in patients developing HC after aSAH.
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Stephan Christen
  • Department of BioMedical Research
Christian Pfister
  • Oeschger Centre for Climate Change Research
University of Bern Hochschulstrasse 4, 3012, Bern, Switzerland