Quantum Trajectories for Time-Local Non-Lindblad Master Equations

For the efficient simulation of open quantum systems, we often use quantum jump trajectories given by pure states that evolve stochastically to unravel the dynamics of the underlying master equation. In the Markovian regime, when the dynamics is described by a Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) master equation, this procedure is known as Monte Carlo wave function approach. However, beyond ultraweak system-bath coupling, the dynamics of the system is not described by an equation of GKSL type, but rather by the Redfield equation, which can be brought into pseudo-Lindblad form. Here, negative dissipation strengths prohibit the conventional approach. To overcome this problem, we propose a pseudo-Lindblad quantum trajectory (PLQT) unraveling. It does not require an effective extension of the state space, like other approaches, except for the addition of a single classical bit. We test the PLQT for the eternal non-Markovian master equation for a single qubit and an interacting Fermi-Hubbard chain coupled to a thermal bath and discuss its computational effort compared to solving the full master equation.

eCross-cultural adaptation of the spine oncology-specific SOSGOQ2.0 questionnaire to German language and the assessment of its validity and reliability in the clinical setting

Background

The recently developed Spine Oncology Study Group Outcomes Questionnaire (SOSGOQ2.0) was proven a valid and reliable instrument measuring health-related quality of life (HRQOL) for patients with spinal malignancies. A German version was not available.

Objective

A cross-cultural adaptation of the SOSGOQ2.0 to the German language and its multicenter evaluation.

Methods

In a multistep process, a cross-cultural adaptation of the SOSGOQ2.0 was conducted. Subsequently, a multicenter, prospective observational cohort study was initiated to assess the reliability and validity of the German adaptation. To assess external construct validity of the cross-cultural adapted questionnaire, a comparison to the established questionnaire QLQ-C30 from the European Organisation for Research and Treatment of Cancer was conducted. Mean-difference plots were used to measure the agreement between the questionnaires in total score and by domain (deviation from mean up to 10% allowed). Further reliability and validity tests were carried out. Change to baseline was analysed 3–16 weeks later after different interventions occurred. Clinically relevant thresholds in comparison to the EORTC QLQ-C30 questionnaire were evaluated by ROC curve analysis.

Results

We could enroll 113 patients from four different university hospitals (58 females, 55 males). Mean age was 64.11 years (sd 11.9). 80 patients had an ECOG performance status of 2 or higher at baseline. External construct validity in comparison to the EORTC QLQ-C30 questionnaire in total score and by domain was confirmed (range of deviation 4.4 to 9.0%). Good responsiveness for the domains Physical Functioning (P < .001) and Pain (P < .001) could be shown. The group mean values also displayed a difference in the domains of Social Functioning (P = .331) and Mental Health (P = .130), but not significant. The minimum clinically relevant threshold values for the questionnaire ranged from 4.0 to 7.5 points.

Conclusions

According to our results, the cross-cultural adapted questionnaire is a reliable and valid tool to measure HRQOL in German speaking patients with spinal malignancies. Especially the domains Physical Functioning and Pain showed overall good psychometric characteristics. In this way, a generic questionnaire, such as the EORTC QLQ-C30, can be usefully supplemented by spine-specific questions to increase the overall accuracy measuring HRQOL in patients with spinal malignancies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08578-x.

OP0199 EX VIVO BIOMARKER PROFILING IDENTIFIES ONCOSTATIN-M AS SPINE OSTEOARTHRITIS-SPECIFIC OSTEOIMMUNOLOGICAL TARGET

Background:

Disease heterogeneity, both clinically and molecularly, has been a major hurdle in the development of efficacious disease-modifying osteoarthritis drugs (DMOADs). Biomechanical, inflammatory, osteoporotic and metabolic OA have been proposed as clinically relevant subtypes for stratification of knee OA patients, yet this remains to be included in clinical trial design. Disease heterogeneity does not only occur within, but also between joint types. However, robust data on joint-specific pathomechanisms of OA are still lacking.

Objectives:

In this study, we performed ex vivo biomarker profiling of human osteochondral tissue of knee and spine OA to identify joint-specific pathomechanisms and DMOAD treatment responses.

Methods:

Facet joint and tibial plateaus were obtained from patients undergoing lumbar spinal fusion (n=11, mean age 72.8) and total joint arthroplasty (n=8, mean age 73.0) respectively. Osteochondral specimens were cut in equal-sized samples (100-300 mg wet weight) and randomly assigned to treatment groups: control (DMSO), inflammation (1 μg/mL LPS) or inflammation + DMOAD (TGF-beta

type I receptor inhibitor,10 μM SB-505124). Explant culture was conducted for one week and biomarkers of bone metabolism (Pro-Col-Ia, SOST, OPG, SPP1), inflammation (MCP-1, IL-6, MMP3, OSM, TIMP1, VEGFA) and cartilage metabolism (ACAN, COMP) were determined by ELISA. Normalized biomarker secretion was analysed using clusteranalyses and ANOVA. Cartilage proteoglycans were assessed by whole mount Alcian blue staining. Expression of Oncostatin-M (OSM) and its receptors OSMR and LIFR in joint tissues was assessed by RT-PCR and immunohistochemistry.

Results:

Clusteranalyses revealed that LPS stimulation increased IL-6 and MCP-1 secretion by both facet joint (FJ) and knee joint (KJ) tissues. Interestingly, Oncostatin-M (OSM) and its downstream mediators MMP3 and TIMP1 were increased in the majority of FJ, but not KJ specimens. Statistical analyses corroborated increased OSM, MMP3 and TIMP1 levels in a spine-specific fashion (Figure).

Whole mount Alcian blue staining revealed heterogeneous effects of LPS treatment on cartilage proteoglycans, which was negatively correlated with OSM (r=-0.54) and TIMP1 levels (r=-0.45) – yet poorly associated with ACAN (r=0.19). Inhibition of TGF-beta type I receptor signalling in osteochondral tissues led to a drastic reduction of Pro-Collagen-Ia and IL-6 secretion in both spine and knee OA specimens. Interestingly, DMOAD treatment significantly reduced OSM, TIMP1 and MMP3 levels in FJ specimens only. Vice versa, KJ tissues revealed a specific upregulation of monocyte chemoattractant protein-1 (MCP-1) and osteopontin (SPP1) upon inhibition of TGF-beta signalling. OSM was exclusively expressed in subchondral bone marrow macrophages. Isolated chondrocytes and osteoblasts expressed both LIFR and OSMR, yet intact cartilage only showed OSMR expression, while OSMR and LIFR was expressed in marrow tissue

Conclusion:

Oncostatin-M expression and signalling was uncovered as specific pathomechanism of spine OA. DMOAD treatment effects suggested interplay of OSM and TGF-beta signalling pathways in facet joint osteoarthritis. Known to be predominantly expressed by macrophages and immune cells, OSM may be an important osteoimmunological mediator of tissue damage and remodelling in spine, but not knee OA. This study also highlights the value of ex vivo human tissue models for OA phenotyping and preclinical evaluation of DMOADs.

Disclosure of Interests:

None declared

First use of the RANKL antibody denosumab in osteogenesis imperfecta type VI

Osteogenesis imperfecta (OI) is a genetically heterogeneous disease leading to bone fragility. OI-VI is an autosomal-recessive form caused by mutations in SERPINF1. There is experimental evidence suggesting that loss of functional SERPINF1 leads to an activation of osteoclasts via the RANK/RANKL pathway. Patients with OI-VI show a poor response to bisphosphonates. We report on four children with OI-VI who had shown continuously elevated urinary bone resorption markers during a previous treatment with bisphosphonates. We treated these children with the RANKL antibody denosumab to reduce bone resorption.

INTERVENTION AND RESULTS

Denosumab (1 mg/kg body weight) was injected s.c. every 3 months. There were no severe side effects. Markers of bone resorption decreased to the normal range after each injection. N-terminal Propeptide of collagen 1 was measured in the serum during the first treatment cycle and decreased also. Urinary deoxypyridinoline/creatinine was monitored in a total of seven treatment cycles and indicated that bone resorption reached the pre-treatment level after 6-8 weeks.

CONCLUSION

This was the first use of denosumab in children with OI-VI. Denosumab was well tolerated, and laboratory parameters provided evidence that the treatment reversibly reduced bone resorption. Therefore, denosumab may be a new therapeutic option for patients with OI-VI.

Global brain dysmyelination with above-average verbal skills in 18q- syndrome with a 17 Mb terminal deletion

BACKGROUND

Patients with the karyotypic finding of a terminal deletion in the long arm of chromosome 18 (18q- syndrome) commonly display cerebral dysmyelination and developmental delay. To our knowledge, all reported cases characterized by molecular analysis who had no mental retardation as confirmed by neuropsychological testing had a chromosomal breakpoint within the two most distal bands, 18q22 or 18q23, leading to a deletion of 16 Mb or less.

AIMS OF THE STUDY

It was the aim of this study to improve the karyotype-phenotype correlation in 18q- syndrome by thoroughly analyzing the deletion size and the mental and radiologic status in a 23-year-old woman with a terminal 18q deletion. We performed cytogenetic and molecular cytogenetic analysis, brain MRI, and extended neuropsychological testing.

RESULTS

Molecular karyotyping revealed a 17 Mb deletion of terminal 18q with a breakpoint in 18q21.33 and no evidence for mosaicism. While brain MRI demonstrated severe global dysmyelination, the patient showed a neuropsychological pattern that allowed for normal psychosocial and job achievement. After delayed development in childhood, the patient caught up during puberty and showed normal verbal intelligence and skills at 23 years. However, visual, visual-spatial, visual-constructional, and executive functions were found to be severely impaired.

CONCLUSION

Here, we present a patient with one of the largest terminal 18q deletions reported in an individual without obvious mental retardation. Our analysis extends the phenotypic spectrum for individuals with breakpoints in 18q21.33. In addition, this study highlights the fact that severe global dysmyelination may not be associated with general cognitive deficits.

Erythropoiesis and performance after two weeks of living high and training low in well trained triathletes

The purpose of our study was to evaluate hematologic acclimatization during 2 weeks of intensive normoxic training with regeneration at moderate altitude (living high-training low, LHTL) and its effects on sea-level performance in well trained athletes compared to another group of equally trained athletes under control conditions (living low - training low, CONTROL). Twenty-one triathletes were ascribed either to LHTL (n = 11; age: 23.0 +/- 4.3 yrs; VO 2 max: 62.5 +/- 9.7 [ml x min -1 x kg -1]) living at 1956 m of altitude or to CONTROL (n = 10; age: 18.7 +/- 5.6 yrs; VO 2 max: 60.5 +/- 6.7 ml x min -1 x kg -1) living at 800 m. Both groups performed an equal training schedule at 800 m. VO 2 max, endurance performance, erythropoietin in serum, hemoglobin mass (Hb tot, CO-rebreathing method) and hematological quantities were measured. A tendency to improved performance in LHTL after the camp was not significant (p < 0.07). Erythropoietin concentration increased temporarily in LHTL (Delta 14.3 +/- 8.7 mU x ml -1; p < 0.012). Hb tot remained unchanged in LHTL whereas was slightly decreased from 12.5 +/- 1.3 to 11.9 +/- 1.3g x kg -1 in CONTROL (p < 0.01). As the reticulocyte number tended to higher values in LHTL than in CONTROL, it seems that a moderate stimulation of erythropoiesis during regeneration at altitude served as a compensation for an exercise-induced destruction of red cells.

SALL1, the gene mutated in Townes-Brocks syndrome, encodes a transcriptional repressor which interacts with TRF1/PIN2 and localizes to pericentromeric heterochromatin

The Townes-Brocks syndrome (TBS) is an autosomal dominantly inherited malformation syndrome presenting as an association of imperforate anus, triphalangeal and supernumerary thumbs, malformed ears and sensorineural hearing loss. Mutations in SALL1, a gene mapping to 16q12.1, were identified as a cause for TBS. To elucidate how SALL1 mutations lead to TBS, we have performed a series of functional studies with the SALL1 protein. Using epifluorescence and confocal microscopy it could be shown that a GFP-SALL1 fusion protein localizes to chromocenters and smaller heterochromatin foci in transiently transfected NIH-3T3 cells. Chromocenters consist of clustered pericentromeric heterochromatin and contain telomere sequences. Indirect immunofluorescence revealed a partial colocalization of GFP-SALL1 with M31, the mouse homolog of the Drosophila heterochromatic protein HP1. It was further demonstrated that SALL1 acts as a strong transcriptional repressor in mammalian cells. Transcriptional repression could not be relieved by the addition of the histone deacetylase inhibitor Trichostatin-A. In a yeast two-hybrid screen we identified PIN2, an isoform of telomere-repeat-binding factor 1 (TRF1), as an interaction partner of SALL1, and showed that the N-terminus of SALL1 is not necessary for the interaction with PIN2/TRF1. The interaction was confirmed in vitro in a GST-pulldown assay. The association of the developmental regulator SALL1 with heterochromatin is striking and unexpected. Our results propose an involvement of SALL1 in the regulation of higher order chromatin structures and indicate that the protein might be a component of a distinct heterochromatin-dependent silencing process. We have also provided new evidence that there is a close functional link between the centromeric and telomeric heterochromatin domains not only in Drosophila and yeast, but also in mammalian cells.

Overnight pulse oximetry for sleep-disordered breathing in adults: a review

Pulse oximetry is a well-established tool routinely used in many settings of modern medicine to determine a patient's arterial oxygen saturation and heart rate. The decreasing size of pulse oximeters over recent years has broadened their spectrum of use. For diagnosis and treatment of sleep-disordered breathing, overnight pulse oximetry helps determine the severity of disease and is used as an economical means to detect sleep apnea. In this article, we outline the clinical utility and economical benefit of overnight pulse oximetry in sleep and breathing disorders in adults and highlight the controversies regarding its limitations as presented in published studies.