Selective mitochondrial Ca2+ uptake deficit in disease endstage vulnerable motoneurons of the SOD1G93A mouse model of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a progressive neurodegenerative disease that targets some somatic motoneuron populations, while others, e.g. those of the oculomotor system, are spared. The pathophysiological basis of this pattern of differential vulnerability, which is preserved in a transgenic mouse model of amyotrophic lateral sclerosis (SOD1(G93A)), and the mechanism of neurodegeneration in general are unknown. Hyperexcitability and calcium dysregulation have been proposed by others on the basis of data from juvenile mice that are, however, asymptomatic. No studies have been done with symptomatic mice following disease progression to the disease endstage. Here, we developed a new brainstem slice preparation for whole-cell patch-clamp recordings and single cell fura-2 calcium imaging to study motoneurons in adult wild-type and SOD1(G93A) mice up to disease endstage. We analysed disease-stage-dependent electrophysiological properties and intracellular Ca(2+) handling of vulnerable hypoglossal motoneurons in comparison to resistant oculomotor neurons. Thereby, we identified a transient hyperexcitability in presymptomatic but not in endstage vulnerable motoneurons. Additionally, we revealed a remodelling of intracellular Ca(2+) clearance within vulnerable but not resistant motoneurons at disease endstage characterised by a reduction of uniporter-dependent mitochondrial Ca(2+) uptake and enhanced Ca(2+) extrusion across the plasma membrane. Our study challenged the notion that hyperexcitability is a direct cause of neurodegeneration in SOD1(G93A) mice, but molecularly identified a Ca(2+) clearance deficit in motoneurons and an adaptive Ca(2+) handling strategy that might be targeted by future therapeutic strategies.

Olfactory Function is Affected in Patients with Cirrhosis Depending on the Severity of Hepatic Encephalopathy

INTRODUCTION AND AIM

Olfactory functions are altered to a variable degree by chronic liver disease. Few studies including only small populations of patients emphasized the possibility of hepatic encephalopathy (HE) influencing olfactory nervous tasks. So far, no study has explicitly focused on olfactory function depending on the severity of HE as assessed by objective diagnostic procedures. Thus we performed a study using the "Sniffin' Sticks" test system, critical flicker-fusion frequency (CFF) and clinical West Haven criteria.

MATERIAL AND METHODS

54 cirrhotic patients with liver cirrhosis were included. Furthermore, 43 adult volunteers participating as a non-cirrhotic control group. Olfactory testing was performed using the "Sniffin' Stick" test battery (Burghart Medizintechnik, Wedel, Germany) which renders a widely-used tool both in clinical and research settings for the assessment of olfactory threshold, odor identification and discrimination. Several complications of cirrhosis were diagnosed by reference methods. Statistical analysis of cirrhosis-associated complications and their relation to olfactory function was performed. Assessment of HE and classification of different stages were performed according to clinical criteria (West- Haven criteria) and according to CFF, which was determined using a portable analyzer.

RESULTS

Olfactory function was significantly reduced in cirrhotic patients (in 61.1%) compared to controls (p < 0.001). Among cirrhotics patients, the prevalence of olfactory deficits (hyposmia, anosmia) increased with the severity of HE as assessed by CFF and clinical criteria (p = 0.008 and p = 0.097, respectively). No correlation was observed between olfactory deficits and severity of liver disease as assessed by Child-Pugh-Score, etiology of cirrhosis and complications of cirrhosis such as ascites and portal venous hypertension.

CONCLUSIONS

Olfactory testing serves as a screening tool for HE and may facilitate grading of HE-severity.

Elevated mRNA-levels of distinct mitochondrial and plasma membrane Ca(2+) transporters in individual hypoglossal motor neurons of endstage SOD1 transgenic mice

Disturbances in Ca²⁺ homeostasis and mitochondrial dysfunction have emerged as major pathogenic features in familial and sporadic forms of Amyotrophic Lateral Sclerosis (ALS), a fatal degenerative motor neuron disease. However, the distinct molecular ALS-pathology remains unclear. Recently, an activity-dependent Ca²⁺ homeostasis deficit, selectively in highly vulnerable cholinergic motor neurons in the hypoglossal nucleus (hMNs) from a common ALS mouse model, the endstage superoxide dismutase SOD1^G93A transgenic mouse, was described. This functional deficit was defined by a reduced hMN mitochondrial Ca²⁺ uptake capacity and elevated Ca²⁺ extrusion across the plasma membrane. To address the underlying molecular mechanisms, here we quantified mRNA-levels of respective potential mitochondrial and plasma membrane Ca²⁺ transporters in individual, choline-acetyltransferase (ChAT) positive hMNs from wildtype (WT) and endstage SOD1^G93A mice, by combining UV laser microdissection with RT-qPCR techniques, and specific data normalization. As ChAT cDNA levels as well as cDNA and genomic DNA levels of the mitochondrially encoded NADH dehydrogenase ND1 were not different between hMNs from WT and endstage SOD1^G93A mice, these genes were used to normalize hMN-specific mRNA-levels of plasma membrane and mitochondrial Ca²⁺ transporters, respectively. We detected about 2-fold higher levels of the mitochondrial Ca²⁺ transporters MCU/MICU1, Letm1, and UCP2 in remaining hMNs from endstage SOD1^G93A mice. These higher expression-levels of mitochondrial Ca²⁺ transporters in individual hMNs were not associated with a respective increase in number of mitochondrial genomes, as evident from hMN specific ND1 DNA quantification. Normalized mRNA-levels for the plasma membrane Na⁺/Ca²⁺ exchanger NCX1 were also about 2-fold higher in hMNs from SOD1^G93A mice. Thus, pharmacological stimulation of Ca²⁺ transporters in highly vulnerable hMNs might offer a neuroprotective strategy for ALS.

[Computed tomography of esophageal carcinoma. Correlation between computed tomographic and postoperative findings]

Between March, 1980 and January, 1984, computerized tomography (CT) was performed on 110 patients with proven esophageal carcinoma. In 26 patients, information obtained preoperatively by CT was compared with results of intraoperative exploration or histologic examination of resection specimen. Correlation analysis showed that accuracy of CT in assessing actual tumor size and mediastinal or abdominal lymph node involvement is rather limited, while correct results were obtained in between 84 and 100 per cent of patients as far as identification of invasion of adjacent organs is concerned. We thus advocate routine use of CT in the process of preoperative assessment of operability and staging.

Hepatopathie bei systemischem Lupus erythematodes – Ergebnisse einer explorativen Beobachtungsstudie

Einleitung Der systemische Lupus erythematodes (SLE) stellt eine klinisch sehr variabel verlaufende Autoimmunerkrankung dar, welche zahlreiche Organsysteme befallen kann. Eine Manifestation an der Leber gilt als selten. Unklar ist insbesondere, ob eine Hepatopathie bei SLE von prognostischer Bedeutung ist und z. B. mit der Aktivität der Erkrankung korreliert.

Methodik Unser Patientenkollektiv umfasste 172 Patienten mit gesichertem SLE, welche am Klinikum Bogenhausen im Zeitraum 01.01.2009 bis 31.12.2015 behandelt wurden. Ausgewertet wurden retrospektiv alle ambulanten und/oder stationären Patientenvorstellungen (n = 671; durchschnittlich 3,9 pro Patient). Eine Leberschädigung wurde laborchemisch anhand von pathologischen Leberenzymprofilen oder bildgebend diagnostiziert. Die Krankheitsaktivität des SLE wurde anhand des European Consensus Lupus Activity Measurement (ECLAM)-Score ermittelt. Zusätzlich wurden Parameter der Grunderkrankung wie Krankheitsdauer, Organschädigung sowie immunsuppressive Medikation ausgewertet und die mögliche Assoziation mit einer Hepatopathie analysiert.

Ergebnisse Erhöhte Leberwerte (ASAT, ALAT, GGT, AP) als Ausdruck einer Hepatopathie waren bei 109 Patienten (63,4 % der Gesamtpopulation) nachweisbar und waren signifikant mit Krankheitsaktivität (auf der Basis des ECLAM-Score, p < 0,001), Behandlungsdauer, Häufigkeit der Vorstellungen (jeweils p < 0,01), Anzahl der eingesetzten Immunsuppressiva (p < 0,018), erhöhter Blutsenkungsgeschwindigkeit (p < 0,001) sowie Erniedrigung des Serumkomplements (p < 0,03) assoziiert. Pathologische Sonografiebefunde an der Leber (z. B. nicht-alkoholische Fettleber) waren in 19,8 % der Fälle nachweisbar.

Diskussion Erhöhte Leberwerte kommen bei Patienten mit SLE sehr häufig vor, insbesondere bei erhöhter Krankheitsaktivität (basierend auf ECLAM-Score oder intensivierter immunsuppressiver Therapie) und längerer Erkrankungsdauer. Leberwertbestimmungen sollten daher bei Patienten mit SLE regelmäßig erfolgen und eine weitere differenzialdiagnostische Abklärung angestrebt werden. Zukünftige prospektive Studien könnten klären, ob pathologische Leberwerte in Aktivitätsindizes zur Beurteilung der Krankheitsaktivität bei SLE einbezogen werden müssen.

[Deficits in Health-Literacy of Inpatients - a Cross-Sectional Study]

INTRODUCTION

Systematic investigations of health literacy in German patients are rare and mostly based on subjective self-assessment.

METHODS

In a cross-sectional survey, 196 patients (female 38 %, male 62 %) in medical and surgical units were asked to complete a questionnaire that we had developed for this purpose. This questionnaire contained 43 questions about common medical terms. We investigated whether patients were familiar with these terms and could name the meaning according to correct definition. Furthermore, the association with the patients' socio-economic and demographic parameters (e. g. education, insurance status, utilization of media) was analyzed.

RESULTS

Among all questions of the questionnaire, more patients claimed to know their meaning than this was the case by objective testing. Association of medical knowledge with demographic and socio-economic data revealed that correct answers were more frequent among women compared to men (51.1 % vs. 47.2 %; p = 0.12). Patients' age was negatively correlated with medical knowledge (p < 0.001). Higher educational level was associated with a higher percentage of correct answers (p < 0.001). Private insurance status had significant influence on medical knowledge (p = 0.002). Male patients working intellectually (compared to working physically) had a higher percentage of correct answers (p = 0.001). Other factors like reading newspapers, watching TV and number of consultations per year did not influence the percentage of correct answers.

SUMMARY

Physicians should make sure by active inquiries whether the patient understands them correctly. Furthermore, there is a considerable gap between subjective and objective medical knowledge that future evaluations of health literacy should be aware of.

Traveler's Diarrhea, vision abnormalities and unsteady gait in a young woman

We report on the course of disease in a young woman, originally admitted with suspected refractory infectious tropical traveler's diarrhea. However, symptoms did not resolve upon either symptomatic or subsequent antibiotic therapy. When neurologic deterioration was observed, imaging studies revealed a dramatic series of thromboembolic events, including intracranial hemorrhage caused by extensive sinus vein thrombosis as well as thrombi of the right cardiac ventricle. Colonic mucosal biopsy samples finally led to the histologic diagnosis of ulcerative colitis. Having excluded thrombophilia or any other disease potentially related to a prothrombotic state, we interpreted the thromboembolic events as secondary to the primary manifestation of the underlying inflammatory bowel disease.The increased risk of thromboembolic complications-especially deep vein thrombosis and pulmonary embolism-in inflammatory bowel disease is well documented in the literature. However, sinus vein thrombosis and cardiac thrombi represent a remarkable dimension of this risk and a rare course of coagulopathy secondary to an acute flare of ulcerative colitis. Still, there is a lack of awareness of this risk, resulting in poor implementation of preventive measures modifying risk factors and allowing for pharmacological prophylaxis. We therefore emphasize that-in line with the 2014 German S3 Guideline-thromboprophylaxis in the setting of an acute flare of inflammatory bowel disease is mandatory and should not be restricted because of safety concerns.

33-jährige Libanesin mit rezidivierenden Hämoptysen und zystischer Raumforderung in der Lunge

A 33 year old woman from Lebanon presented with recurrent hemoptysis, subfebrile temperature, dyspnoe in stress, fatigue, weight loss, and pruritus. Serological tests and results from chest X-ray and computer tomography revealed cystic echinococcosis with pulmonary involvement. After refusal of surgical therapy a medical treatment with albendazole was implemented. Two months after the start of the therapy only a small fibrotic residuum in the lung was seen. A spontaneous healing success seems unlikely because of the duration of the pulmonary cyst and the progressive symptoms before treatment.

Comparing Virtual Reality-Based and Traditional Physical Objective Structured Clinical Examination (OSCE) Stations for Clinical Competency Assessments: Randomized Controlled Trial

BACKGROUND

Objective structured clinical examinations (OSCEs) are a widely recognized and accepted method to assess clinical competencies but are often resource-intensive.

OBJECTIVE

This study aimed to evaluate the feasibility and effectiveness of a virtual reality (VR)-based station (VRS) compared with a traditional physical station (PHS) in an already established curricular OSCE.

METHODS

Fifth-year medical students participated in an OSCE consisting of 10 stations. One of the stations, emergency medicine, was offered in 2 modalities: VRS and PHS. Students were randomly assigned to 1 of the 2 modalities. We used 2 distinct scenarios to prevent content leakage among participants. Student performance and item characteristics were analyzed, comparing the VRS with PHS as well as with 5 other case-based stations. Student perceptions of the VRS were collected through a quantitative and qualitative postexamination online survey, which included a 5-point Likert scale ranging from 1 (minimum) to 5 (maximum), to evaluate the acceptance and usability of the VR system. Organizational and technical feasibility as well as cost-effectiveness were also evaluated.

RESULTS

Following randomization and exclusions of invalid data sets, 57 and 66 participants were assessed for the VRS and PHS, respectively. The feasibility evaluation demonstrated smooth implementation of both VR scenarios (septic and anaphylactic shock) with 93% (53/57) of students using the VR technology without issues. The difficulty levels of the VRS scenarios (septic shock: P=.67; anaphylactic shock: P=.58) were comparable to the average difficulty of all stations (P=.68) and fell within the reference range (0.4-0.8). In contrast, VRS demonstrated above-average values for item discrimination (septic shock: r'=0.40; anaphylactic shock: r'=0.33; overall r'=0.30; with values >0.3 considered good) and discrimination index (septic shock: D=0.25; anaphylactic shock: D=0.26; overall D=0.16, with 0.2-0.3 considered mediocre and <0.2 considered poor). Apart from some hesitancy toward its broader application in future practical assessments (mean 3.07, SD 1.37 for VRS vs mean 3.65, SD 1.18 for PHS; P=.03), there were no other differences in perceptions between VRS and PHS. Thematic analysis highlighted the realistic portrayal of medical emergencies and fair assessment conditions provided by the VRS. Regarding cost-effectiveness, initial development of the VRS can be offset by long-term savings in recurring expenses like standardized patients and consumables.

CONCLUSIONS

Integration of the VRS into the current OSCE framework proved feasible both technically and organizationally, even within the strict constraints of short examination phases and schedules. The VRS was accepted and positively received by students across various levels of technological proficiency, including those with no prior VR experience. Notably, the VRS demonstrated comparable or even superior item characteristics, particularly in terms of discrimination power. Although challenges remain, such as technical reliability and some acceptance concerns, VR remains promising in applications of clinical competence assessment.

Virtual reality for assessing emergency medical competencies in junior doctors - a pilot study

BACKGROUND

The teaching and assessment of clinical-practical skills in medical education face challenges in adequately preparing students for professional practice, especially in handling emergency situations. This study aimed to evaluate the emergency medical competencies of junior doctors using Virtual Reality (VR)-based scenarios to determine their preparedness for real-world clinical situations.

METHODS

Junior doctors with 0-6 months of professional experience participated in one of three VR-based emergency scenarios. These scenarios were designed to test competencies in emergency medical care. Performance was automatically assessed through a scenario-specific checklist, and participants also completed self-assessments and a clinical reasoning ability test using the Post-Encounter Form.

RESULTS

Twenty-one junior doctors participated in the study. Results showed that while general stabilization tasks were performed well, there were notable deficiencies in disease-specific diagnostic and therapeutic actions. On average, 65.6% of the required actions were performed correctly, with no significant variance between different scenarios. Participants achieved an average score of 80.5% in the Post-Encounter-Form, indicating a robust ability to handle diagnostic decisions. Self-assessments did not correlate significantly with objective measures of competency, highlighting the subjective nature of self-evaluation.

CONCLUSION

VR-based simulations can provide a detailed picture of EMC, covering both diagnostic and therapeutic aspects. The findings of this pilot study suggest that while participants are generally well-prepared for routine tasks, more focus is needed on complex case management. VR assessments could be a promising tool for evaluating the readiness of new medical professionals for clinical practice.

Overlap of concurrent extrahepatic autoimmune diseases is associated with milder disease severity of newly diagnosed autoimmune hepatitis

BACKGROUND

Concurrent extrahepatic autoimmune disorders (CEHAID) are frequently observed in autoimmune hepatitis (AIH). It is not clear whether there is any prognostic significance of CEHAID on AIH. The aim of this study was to examine the prognostic impact of CEHAID and the correlation with the disease severity of AIH.

METHODS

This study included 65 hospitalized subjects who fulfilled the accepted criteria for AIH during an 8-year period (2009-2016). All records were manually screened for presence of associated autoimmune diseases. Disease severity of AIH was assessed by liver laboratory tests including the ratio of aspartate aminotransferase to alanine aminotransferase (AST/ALT) and liver histology.

RESULTS

Among the enrolled patients, 52 (80%) were female (median age 61 years, IQR 45-75). Fifty-six (86.2%) were classified as type-1 AIH. In 26 (40%) patients at least one additional extrahepatic autoimmune disease was diagnosed. Thirty-four subjects were referred to our hospital because of acute presentation of AIH (supposed by an acute elevation of hepatic enzymes) for subsequent liver biopsy resulting in initial diagnosis of AIH. This group was stratified into 3 subgroups: (A) AIH alone (n = 14); (B) overlap with primary biliary cirrhosis (PBC) / primary sclerosing cholangitis (PSC) (n = 11); and (C) with CEHAID (n = 9). AST/ALT ratio was the lowest in subgroup C (median 0.64, IQR 0.51-0.94; P = 0.023), compared to subgroup A (median 0.91, IQR 0.66-1.10) and subgroup B (median 1.10, IQR 0.89-1.36). Patients with AIH alone showed a trend to the highest grade of fibrosis (mean 2.3; 95% CI: 1.5-3.0) with no statistical significance compared to subjects with CEHAID (lowest grade of fibrosis; mean 1.5; 95% CI: 0.2-2.8; P = 0.380) whereas the ongoing inflammation was comparable.

CONCLUSIONS

AST/ALT ratio and extent of fibrosis were lower in subjects with AIH and CEHAID, compared to subjects with only AIH. Therefore, the occurrence of CEHAID might be a predictor for lower disease severity of newly diagnosed acute onset AIH, possibly caused by an earlier diagnosis or different modes of damage.