Viscosity Modeling for Blood and Blood Analog Fluids in Narrow Gap and High Reynolds Numbers Flows

For the optimization of ventricular assist devices (VADs), flow simulations are crucial. Typically, these simulations assume single-phase flow to represent blood flow. However, blood consists of plasma and blood cells, making it a multiphase flow. Cell migration in such flows leads to a heterogeneous cell distribution, significantly impacting flow dynamics, especially in narrow gaps of less than 300 μm found in VADs. In these areas, cells migrate away from the walls, forming a cell-free layer, a phenomenon not usually considered in current VAD simulations. This paper addresses this gap by introducing a viscosity model that accounts for cell migration in microchannels under VAD-relevant conditions. The model is based on local particle distributions measured in a microchannels with a blood analog fluid. We developed a local viscosity distribution for flows with particles/cells and a cell-free layer, applicable to both blood and analog fluids, with particle volume fractions of up to 5%, gap heights of 150 μm, and Reynolds numbers around 100. The model was validated by comparing simulation results with experimental data of blood and blood analog fluid flow on wall shear stresses and pressure losses, showing strong agreement. This model improves the accuracy of simulations by considering local viscosity changes rather than assuming a single-phase fluid. Future developments will extend the model to physiological volume fractions up to 40%.

Management of Neurogenic Respiratory Alkalosis and Concomitant Lactatemia After Resection of a Posterior Fossa Meningioma: A Case Report

Central neurogenic hyperventilation (CNH) is a rare disease, caused by chemical or mechanical disturbance of respiratory centers. It is characterized by the absence of extracerebral respiratory stimuli. A woman developed severe respiratory alkalosis and lactatemia after resection of a posterior fossa meningioma despite lack of cardio-respiratory or metabolic alterations. Cerebral computed tomography (cCT) revealed edema of the pontomedullary area. Treatment with mannitol and dexamethasone reestablished normal breathing patterns. Lactatemia was likely due to reduced splanchnic lactate utilization. Intracranial pathologies should be suspected in case of hyperventilation without overt reasons. cCT to confirm edema or ischemia and prompt treatment is suggested.

French guidelines for the diagnosis and management of Tourette syndrome

The term "Gilles de la Tourette syndrome", or the more commonly used term "Tourette syndrome" (TS) refers to the association of motor and phonic tics which evolve in a context of variable but frequent psychiatric comorbidity. The syndrome is characterized by the association of several motor tics and at least one phonic tic that have no identifiable cause, are present for at least one year and appear before the age of 18. The presence of coprolalia is not necessary to establish or rule out the diagnosis, as it is present in only 10% of cases. The diagnosis of TS is purely clinical and is based on the symptoms defined by the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). No additional tests are required to confirm the diagnosis of TS. However, to exclude certain differential diagnoses, further tests may be necessary. Very frequently, one or more psychiatric comorbidities are also present, including attention deficit hyperactivity disorder, obsessive-compulsive disorder, anxiety, explosive outbursts, self-injurious behaviors, learning disorders or autism spectrum disorder. The condition begins in childhood around 6 or 7 years of age and progresses gradually, with periods of relative waxing and waning of tics. The majority of patients experience improvement by the end of the second decade of life, but symptoms may persist into adulthood in around one-third of patients. The cause of TS is unknown, but genetic susceptibility and certain environmental factors appear to play a role. The treatment of TS and severe forms of tics is often challenging and requires a multidisciplinary approach (involving the general practitioner (GP), pediatrician, psychiatrist, neurologist, school or occupational physicians, psychologist and social workers). In mild forms, education (of young patients, parents and siblings) and psychological management are usually recommended. Medical treatments, including antipsychotics, are essential in the moderate to severe forms of the disease (i.e. when there is a functional and/or psychosocial discomfort linked to tics). Over the past decade, cognitive-behavioral therapies have been validated for the treatment of tics. For certain isolated tics, botulinum toxin injections may also be useful. Psychiatric comorbidities, when present, often require a specific treatment. For very severe forms of TS, treatment by deep brain stimulation offers real therapeutic hope. If tics are suspected and social or functional impairment is significant, specialist advice should be sought, in accordance with the patient's age (psychiatrist/child psychiatrist; neurologist/pediatric neurologist). They will determine tic severity and the presence or absence of comorbidities. The GP will take over the management and prescription of treatment: encouraging treatment compliance, assessing side effects, and combating stigmatization among family and friends. They will also play an important role in rehabilitation therapies, as well as in ensuring that accommodations are made in the patient's schooling or professional environment.

DNA demethylation and tri-methylation of H3K4 at the TACSTD2 promoter are complementary players for TROP2 regulation in colorectal cancer cells

TROP2 is a powerful cancer driver in colorectal cancer cells. Divergent epigenetic regulation mechanisms for the corresponding TACSTD2 gene exist such as miRNAs or DNA methylation. However, the role of TACSTD2 promoter hypermethylation in colorectal cancer has not been investigated yet. In this study, TROP2 expression strongly correlated with promoter methylation in different colorectal tumor cell lines. Treatment with 5-Azacytidine, a DNMT1 inhibitor, led to demethylation of the TACSTD2 promoter accompanied by an increase in TROP2 protein expression. TROP2 expression correlated with promoter methylation in vivo in human colon tumor tissue, thereby verifying promoter methylation as an important factor in the regulation of TROP2 expression in colorectal cancer. When performing a ChIP-Seq analysis in HCT116 and HT29 cells, we found that TACSTD2 promoter demethylation was accompanied by tri-methylation of H3K4. In silico analysis of GSE156613 data set confirmed that a higher binding of histone mark H3K4me3 around the TACSTD2 promoter was found in TACSTD2 high expressing tumors of colon cancer patients compared to the corresponding adjacent tumor tissue. Moreover, the link between TROP2 and the H3K4me3 code was even evident in tumors showing high intratumoral heterogeneity for TROP2 staining. Our data provide novel evidence for promoter demethylation and simultaneous gains of the active histone mark H3K4me3 across CpG-rich sequences, both being complementary mechanisms in the transcriptional regulation of TACSTD2 in colon cancer. The functional consequences of TROP2 loss in colorectal cancer needs to be further investigated.

[Career prospects for ophthalmologists under 49 years old : A survey in Germany from 2022]

OBJECTIVE

The need for care in ophthalmology is constantly increasing due to demographic changes. The study analyzed the current professional situation and future prospects of ophthalmologists under 49 years old.

METHODS

The survey of members of the German Association of Ophthalmologists (Berufsverband der Augenärzte Deutschlands) and the German Ophthalmologic Society (Deutsche Ophthalmologische Gesellschaft) was conducted in 2022. All members under the age of 49 years received an online questionnaire on the current professional situation as well as future perspectives (desired working hours, form of organization). The results of the survey were additionally compared with the 2016 survey of the German Association of Ophthalmologists. A similar questionnaire was used at that time.

RESULTS

A total of 1014 people participated in the survey (62.7% women, mean age 39.3 ± 8 years, 75.6% specialists). The response rate to the survey was 25%. Specialist practice from 0 to 5 years showed a higher number of employed ophthalmologists (21% self-employed vs. 32% employed); over time the number of self-employed ophthalmologists increased (6-10 years: 40%, > 10 years: 59.3%). Overall, 46% of women were employed in a practice compared with 33% of men. Of the self-employed specialists, 95.9% said they planned to work in the same type of employment in 10 years as currently. Regarding ophthalmologists' career future, the other employment types showed a desire to move to independent practice. Compared to the 2016 survey, gender differences related to the current type of employment were evident. The number of self-employed women decreased from 43% to 26% and self-employed men decreased from 63% to 39%. The number of ophthalmologists in ambulatory healthcare centers was doubled compared to 2016. Ophthalmologists reported similar future perspectives at both survey times.

CONCLUSION

The results of the survey of ophthalmologists under 49 years in Germany showed similar perceptions as in 2016. It became clear that the desire to be self-employed in 10 years is very high; however, ophthalmologists expected large practices or medical care centers to prevail in the market. The number of self-employed doctors is decreasing and the desire for self-employment is difficult to realize.

WHO 2022 classification of penile and scrotal cancers: updates and evolution

Squamous cell carcinoma (SCC) is the most common malignant tumour of the penis. The 2022 WHO classification reinforces the 2016 classification and subclassifies precursor lesions and tumours into human papillomavirus (HPV)-associated and HPV-independent types. HPV-associated penile intraepithelial neoplasia (PeIN) is a precursor lesion of invasive HPV- associated SCC, whereas differentiated PeIN is a precursor lesion of HPV-independent SCC. Block-type positivity of p16 immunohistochemistry is the most practical daily utilised method to separate HPVassociated from HPVindependent penile SCC. If this is not feasible, the term SCC, not otherwise specified (NOS) is appropriate. Certain histologies that were previously classified as "subtypes" are now grouped, and coalesced as "patterns", under the rubric of usual type SCC and verrucous carcinoma (e.g. usual-type SCC includes pseudohyperplastic and acantholytic/pseudoglandular carcinoma, and carcinoma cuniculatum is included as a pattern of verrucous carcinoma). If there is an additional component of the usual type of invasive SCC (formerly termed hybrid histology), the tumour would be a mixed carcinoma (e.g. carcinoma cuniculatum or verrucous carcinoma with usual invasive SCC); in such cases, reporting of the relative percentages in mixed tumours may be useful. The consistent use of uniform nomenclature and reporting of percentages will inform the refinement of future reporting classification schemes and guidelines/recommendations. The classification of scrotal tumours is provided for the first time in the fifth edition of the WHO Blue book, and it follows the schema of penile cancer classification for both precursor lesions and the common SCC of the scrotum. Basal cell carcinoma of the scrotum may have a variable clinical course and finds a separate mention.

Systematic estimation of biological age of in vitro cell culture systems by an age-associated marker panel

Aging is a process that affects almost all multicellular organisms and since our population ages with increasing prevalence of age-related diseases, it is important to study basic processes involved in aging. Many studies have been published so far using different and often single age markers to estimate the biological age of organisms or different cell culture systems. However, comparability of studies is often hampered by the lack of a uniform panel of age markers. Consequently, we here suggest an easy-to-use biomarker-based panel of classical age markers to estimate the biological age of cell culture systems that can be used in standard cell culture laboratories. This panel is shown to be sensitive in a variety of aging conditions. We used primary human skin fibroblasts of different donor ages and additionally induced either replicative senescence or artificial aging by progerin overexpression. Using this panel, highest biological age was found for artificial aging by progerin overexpression. Our data display that aging varies depending on cell line and aging model and even from individual to individual showing the need for comprehensive analyses.

Markers of bone metabolism are associated in all-cause mortality in heart failure with reduced ejection fraction

Background

In patients with heart failure an increased risk of fracture-related mortality has been reported. A growing body of evidence suggests that, heart failure (HF) itself may be related to disturbances in bone metabolism, but the exact mechanism remains unclear. In patients with HF previous studies indicated a loss of renal function and alterations in bone micro-architecture, but the clinical relevance remains unclear.

Purpose

We aimed to evaluate the association between markers of bone metabolism with mortality and pro-brain natriuretic peptide (proBNP) in patients with HF with reduced ejection fraction (HFrEF).

Methods

We analysed participants of a prospective cohort study of patients referred to coronary angiography (CA). The baseline examination was performed at a tertiary care centre in Germany. Indications for CA were based on clinical routine. For the current analysis only patients with HFrEF were included. Patients were selected based on echocardiographic left ventricular (LV)-EF≤40%, symptoms of heart failure and elevated proBNP concentrations, as recommended by current clinical guidelines.

We estimated the risk associated with parathyroid hormone (PTH), osteocalcin (OC), beta-crosslaps (βCL) and alkaline phosphatase (AP) and all-cause mortality using Cox proportional hazard models. Adjustments for demographic and clinical characteristics from the index hospital presentation were used as covariates. We included all individuals who had complete data for all variables in the study in our primary analysis. Additionally, we used linear regression analysis to investigate the correlation between proBNP and its association with PTH, OC, βCL and AP.

Results

A total of 297 participants (63.9±9.9 years; 17.9% females) were included in the analysis. Median follow-up was 10 years. Median LV-EF was 35%, median New York Heart Association functional class was 2 (IQR=1–3), mean pulmonary capillary wedge pressure was 15.3±7.4 mmHg and median proBNP levels of 2282 (IQR 1875–3758) ng/ml. Participants had in 42.3% multi-vessel atherosclerotic CAD (with stenosis of ≥50% considered diagnostic) with 66.4% had a previous myocardial infarction. In multivariate cox proportionate hazard models OC, βCL and AP were statistically significant associated with an increased risk for all-cause mortality (hazard ratio (HR)=1.6 [95% CI 1.2–2.2], HR=1.8 [95% CI 1.1–2.9] and HR=2.1 [95% CI 1.5–2.9], respectively).

In multivariate analysis proBNP was associated with PTH (β-coefficient = 0.076; P≤0.001), AP (β-coefficient = 0.125; P=0.001) and βCL (β-coefficient = 0.062; P=0.046), but not with osteocalcin (β-coefficient = −0.055; P=0.145).

Conclusion

In patients with HFrEF markers of bone metabolism were significantly associated with mortality and proBNP concentrations. Future studies should focus on different aspects of bone metabolism, fracture rates and fracture related mortality in patients with different stages of heart failure.

Funding Acknowledgement

Type of funding sources: None.

[Accreditation in pathology and neuropathology in Germany : General regulations and requirements]

Accreditation in pathology and neuropathology in Germany is based on the requirements of the DIN EN ISO/IEC 17020 standard, which defines general requirements for the bodies performing inspections. In Germany, the national accreditation body of the Federal Republic of Germany (DAkkS) assumes the official task of accreditation. Evaluation in this area is based on a comprehensive assessment by board-certified pathologists (inspection) and is focused on correct diagnosis. The requirement of the DIN EN ISO 15189 standard on quality and competence in medical laboratories is taken into account. In Germany, more than 100 institutes of pathology and neuropathology have successfully performed the accreditation process. Interest in accreditation has been significantly growing in recent months, especially due to changes in the European law with the "Verordnung EO 2017/746 des Europäischen Parlaments und des Rates vom 05. April 2017 über Invitro-Diagnostica".However, accreditation is a demanding process that requires very good preparation. Necessary resources for accreditation should be secured before starting the process. Important framework conditions and requirements, but also some challenges that can arise during the accreditation process, are summarized in this article.

A conserved long-distance telomeric silencing mechanism suppresses mTOR signaling in aging human fibroblasts

Telomeres are repetitive nucleotide sequences at the ends of each chromosome. It has been hypothesized that telomere attrition evolved as a tumor suppressor mechanism in large long-lived species. Long telomeres can silence genes millions of bases away through a looping mechanism called telomere position effect over long distances (TPE-OLD). The function of this silencing mechanism is unknown. We determined a set of 2322 genes with high positional conservation across replicatively aging species that includes known and candidate TPE-OLD genes that may mitigate potentially harmful effects of replicative aging. Notably, we identified PPP2R2C as a tumor suppressor gene, whose up-regulation by TPE-OLD in aged human fibroblasts leads to dephosphorylation of p70S6 kinase and mammalian target of rapamycin suppression. A mechanistic link between telomeres and a tumor suppressor mechanism supports the hypothesis that replicative aging fulfills a tumor suppressor function and motivates previously unknown antitumor and antiaging strategies.

[Outcome of selective mating in the Entlebucher Mountain Dog for reduction of ureteral ectopia]

INTRODUCTION

The Entlebucher Mountain Dog is predisposed to ureteral ectopia and associated diseases of the urinary tract as well as the kidneys, which can have severe to lethal consequences. Due to the clustered occurrence of clinical signs in 11 % of Entlebucher Mountain dogs in the absence of a genetic test for ureteral ectopia, screening was introduced in 2008 to allow phenotype-based breeding selection. The ureteral orifices of the dogs are visualized by ultrasound and existing urinary retention or urinary incontinence is documented. The diagnostic findings were evaluated centrally with assignment to one of five phenotypes depending on the localization of the ureteral orifices and the renal and ureteral shape. Breeding approval and mating restrictions are the responsibility of the respective breeding associations and predominantly Entlebucher Mountain Dogs with extravesical ectopic ureters and/or clinical signs were excluded from breeding. The effect of phenotype-based selective mating on the incidence of ureteral ectopia and its clinical signs, as well as possible factors influencing the expression of the phenotype, were determined in the birth cohorts after the introduction of screening. Analysis of the data set of 1456 phenotyped Entlebucher Mountain Dogs showed, that at 11 % versus 5 %, males were more frequently assigned to the extravesical phenotype than females. The effect of phenotype-based breeding selection was examined in a subpopulation consisting of phenotyped parents and their offspring (n = 876). The prevalence of the extravesical phenotype decreased from 24 % in the 2005 to 2007 birth cohorts to 1,4 % in the 2015 to 2017 birth cohorts. Since 2015 almost no Entlebucher Mountain Dogs with incontinence, hydroureter or hydronephrosis have been recorded. It was feared that the additional selection measures to control ureteral ectopia in the small Entlebucher Mountain Dog population would intensify the inbreeding increase. However, this has so far remained absent. Therefore, as long as no genetic test is available, it is recommended to continue phenotype-based breeding selection with exclusion of dogs with extravesical ureteral ectopia and/or hydroureter/hydronephrosis/urinary incontinence, while keeping an eye on the development of the inbreeding coefficient.

F18-FDG PET/CT imaging early predicts pathologic complete response to induction chemoimmunotherapy of locally advanced head and neck cancer: preliminary single-center analysis of the checkrad-cd8 trial

Aim

In the CheckRad-CD8 trial patients with locally advanced head and neck squamous cell cancer are treated with a single cycle of induction chemo-immunotherapy (ICIT). Patients with pathological complete response (pCR) in the re-biopsy enter radioimmunotherapy. Our goal was to study the value of F-18-FDG PET/CT in the prediction of pCR after induction therapy.

Methods

Patients treated within the CheckRad-CD8 trial that additionally received FDG- PET/CT imaging at the following two time points were included: 3–14 days before (pre-ICIT) and 21–28 days after (post-ICIT) receiving ICIT. Tracer uptake in primary tumors (PT) and suspicious cervical lymph nodes (LN +) was measured using different quantitative parameters on EANM Research Ltd (EARL) accredited PET reconstructions. In addition, mean FDG uptake levels in lymphatic and hematopoietic organs were examined. Percent decrease (Δ) in FDG uptake was calculated for all parameters. Biopsy of the PT post-ICIT acquired after FDG-PET/CT served as reference. The cohort was divided in patients with pCR and residual tumor (ReTu).

Results

Thirty-one patients were included. In ROC analysis, ΔSUVmax PT performed best (AUC = 0.89) in predicting pCR (n = 17), with a decline of at least 60% (sensitivity, 0.77; specificity, 0.93). Residual SUVmax PT post-ICIT performed best in predicting ReTu (n = 14), at a cutpoint of 6.0 (AUC = 0.91; sensitivity, 0.86; specificity, 0.88). Combining two quantitative parameters (ΔSUVmax ≥ 50% and SUVmax PT post-ICIT ≤ 6.0) conferred a sensitivity of 0.81 and a specificity of 0.93 for determining pCR. Background activity in lymphatic organs or uptake in suspected cervical lymph node metastases lacked significant predictive value.

Conclusion

FDG-PET/CT can identify patients with pCR after ICIT via residual FDG uptake levels in primary tumors and the related changes compared to baseline. FDG-uptake in LN + had no predictive value.

Trial registry

ClinicalTrials.gov identifier: NCT03426657.

[Update on collaborative autopsy-based research in German pathology, neuropathology, and forensic medicine]

BACKGROUND

Autopsies are a valuable tool for understanding disease, including COVID-19.

MATERIALS AND METHODS

The German Registry of COVID-19 Autopsies (DeRegCOVID), established in April 2020, serves as the electronic backbone of the National Autopsy Network (NATON), launched in early 2022 following DEFEAT PANDEMIcs.

RESULTS

The NATON consortium's interconnected, collaborative autopsy research is enabled by an unprecedented collaboration of 138 individuals at more than 35 German university and non-university autopsy centers through which pathology, neuropathology, and forensic medicine autopsy data including data on biomaterials are collected in DeRegCOVID and tissue-based research and methods development are conducted. More than 145 publications have now emerged from participating autopsy centers, highlighting various basic science and clinical aspects of COVID-19, such as thromboembolic events, organ tropism, SARS-CoV‑2 detection methods, and infectivity of SARS-CoV-2 at autopsy.

CONCLUSIONS

Participating centers have demonstrated the high value of autopsy and autopsy-derived data and biomaterials to modern medicine. The planned long-term continuation and further development of the registry and network, as well as the open and participatory design, will allow the involvement of all interested partners.

Biomarkers of geroprotection and cardiovascular health: An overview of omics studies and established clinical biomarkers in the context of diet

The slowdown, inhibition, or reversal of age-related decline (as a composite of disease, dysfunction, and, ultimately, death) by diet or natural compounds can be defined as dietary geroprotection. While there is no single reliable biomarker to judge the effects of dietary geroprotection, biomarker signatures based on omics (epigenetics, gene expression, microbiome composition) are promising candidates. Recently, omic biomarkers started to supplement established clinical ones such as lipid profiles and inflammatory cytokines. In this review, we focus on human data. We first summarize the current take on genetic biomarkers based on epidemiological studies. However, most of the remaining biomarkers that we describe, whether omics-based or clinical, are related to intervention studies. Then, because of their promising potential in the context of dietary geroprotection, we focus on the effects of berry-based interventions, which up to now have been mostly described employing clinical markers. We provide an aggregation and tabulation of all the recent systematic reviews and meta-analyses that we could find related to this topic. Finally, we present evidence for the importance of the "nutribiography," that is, the influence that an individual's history of diet and natural compound consumption can have on the effects of dietary geroprotection.

Deep learning for diagnosis and survival prediction in soft tissue sarcoma

BACKGROUND

Clinical management of soft tissue sarcoma (STS) is particularly challenging. Here, we used digital pathology and deep learning (DL) for diagnosis and prognosis prediction of STS.

PATIENTS AND METHODS

Our retrospective, multicenter study included a total of 506 histopathological slides from 291 patients with STS. The Cancer Genome Atlas cohort (240 patients) served as training and validation set. A second, multicenter cohort (51 patients) served as an additional test set. The use of the DL model (DLM) as a clinical decision support system was evaluated by nine pathologists with different levels of expertise. For prognosis prediction, 139 slides from 85 patients with leiomyosarcoma (LMS) were used. Area under the receiver operating characteristic (AUROC) and accuracy served as main outcome measures.

RESULTS

The DLM achieved a mean AUROC of 0.97 (±0.01) and an accuracy of 79.9% (±6.1%) in diagnosing the five most common STS subtypes. The DLM significantly improved the accuracy of the pathologists from 46.3% (±15.5%) to 87.1% (±11.1%). Furthermore, they were significantly faster and more certain in their diagnosis. In LMS, the mean AUROC in predicting the disease-specific survival status was 0.91 (±0.1) and the accuracy was 88.9% (±9.9%). Cox regression showed the DLM's prediction to be a significant independent prognostic factor (P = 0.008, hazard ratio 5.5, 95% confidence interval 1.56-19.7) in these patients, outperforming other risk factors.

CONCLUSIONS

DL can be used to accurately diagnose frequent subtypes of STS from conventional histopathological slides. It might be used for prognosis prediction in LMS, the most prevalent STS subtype in our cohort. It can also help pathologists to make faster and more accurate diagnoses. This could substantially improve the clinical management of STS patients.