Anaerobic dihydrogen consumption of nutrient-limited aquifer sediment microbial communities examined by stable isotope analysis

The biogeochemical consequences of dihydrogen (H2) underground storage in porous aquifers are poorly understood. Here, the effects of nutrient limitations on anaerobic H2 oxidation of an aquifer microbial community in sediment microcosms were determined in order to evaluate possible responses to high H2 partial pressures. Hydrogen isotope analyses of H2 yielded isotope depletion in all biotic setups indicating microbial H2 consumption. Carbon isotope analyses of carbon dioxide (CO2) showed isotope enrichment in all H2-supplemented biotic setups indicating H2-dependent consumption of CO2 by methanogens or homoacetogens. Homoacetogenesis was indicated by the detection of acetate and formate. Consumption of CO2 and H2 varied along the differently nutrient-amended setups, as did the onset of methane production. Plotting carbon against hydrogen isotope signatures of CH4 indicated that CH4 was produced hydrogenotrophically and fermentatively. The putative hydrogenotrophic Methanobacterium sp. was the dominant methanogen. Most abundant phylotypes belonged to typical ferric iron reducers, indicating that besides CO2, Fe(III) was an important electron acceptor. In summary, our study provides evidence for the adaptability of subsurface microbial communities under different nutrient-deficient conditions to elevated H2 partial pressures.

The PerPAIN trial: a pilot randomized controlled trial of personalized treatment allocation for chronic musculoskeletal pain-a protocol

BACKGROUND

The therapy of chronic musculoskeletal pain (CMSP) is complex and the treatment results are often insufficient despite numerous therapeutic options. While individual patients respond very well to specific interventions, other patients show no improvement. Personalized treatment assignment offers a promising approach to improve response rates; however, there are no validated cross-disease allocation algorithms available for the treatment of chronic pain in validated personalized pain interventions. This trial aims to test the feasibility and safety of a personalized pain psychotherapy allocation with three different treatment modules and estimate initial signals of efficacy and utility of such an approach compared to non-personalized allocation.

METHODS

This is a randomized, controlled assessor-blinded pilot trial with a multifactorial parallel arm design. CMSP patients (n = 105) will be randomly assigned 1:1 to personalized or non-personalized treatment based on a cluster assignment of the West Haven-Yale Multidimensional Pain Inventory (MPI). In the personalized assignment condition, patients with high levels of distress receive an emotional distress-tailored intervention, patients with pain-related interference receive an exposure/extinction-tailored treatment intervention and patients who adapt relatively well to the pain receive a low-level smartphone-based activity diary intervention. In the control arm, patients receive one of the two non-matching interventions. Effect sizes will be calculated for change in core pain outcome domains (pain intensity, physical and emotional functioning, stress experience, participant ratings of improvement and satisfaction) after intervention and at follow-up. Feasibility and safety outcomes will assess rates of recruitment, retention, adherence and adverse events. Additional data on neurobiological and psychological characteristics of the patients are collected to improve treatment allocation in future studies.

CONCLUSION

Although the call for personalized treatment approaches is widely discussed, randomized controlled trials are lacking. As the personalization of treatment approaches is challenging, both allocation and intervention need to be dynamically coordinated. This study will test the feasibility and safety of a novel study design in order to provide a methodological framework for future multicentre RCTs for personalized pain psychotherapy.

TRIAL REGISTRATION

German Clinical Trials Register, DRKS00022792 ( https://www.drks.de ). Prospectively registered on 04/06/2021.

Understanding eating-related health outcomes: connections between anxiety and eating behavior

Background

Research shows that anxiety is connected to a variety of mental health outcomes, and that it is widespread among the population. In the light of the great personal and societal costs of obesity and eating disorders, we want to understand the connection between anxiety and different dimensions of eating behaviors that have a strong empirical link with negative eating-related health outcomes.

Methods

We used data from the population- based LIFE-Adult-Study (n = 5019) to analyze the connection between anxiety (GAD-7) and the three dimensions of eating behaviors: Cognitive Restraint, Disinhibition, and Hunger (FEV, German version of the Three-Factor-Eating-Questionnaire). We controlled for sociodemographic variables, smoking, physical activity, personality, and social support.

Results

Multivariate regression analyses showed significant positive associations between anxiety and Disinhibition (β = 0.23, p ≤ 0.001), Hunger (β = 0.21, p ≤ 0.001) and Cognitive Restraint (β = 0.04, p ≤ 0.01). After adding control variables, analyses revealed significant positive associations between anxiety and Disinhibition (β = 0.15, p ≤ 0.001) as well as Hunger (β = 0.14, p ≤ 0.001), but not between anxiety and Cognitive Restraint (β = 0.03, p = 0.076).

Conclusions

There is an empirical connection between anxiety and two factors of eating behavior, i.e., Disinhibition and Hunger. If future research strengthens the assumption of a causal direction from anxiety to those factors, interventions that help individuals to better regulate and cope with anxiety, could be one potential pathway to reducing eating disorders and obesity in the population.

Key messages

• There is a significant connection between anxiety and eating behavior.

• Interventions that address anxiety could reduce problematic eating-related health outcomes like eating disorders and obesity.

P14.108 Bevacizumab versus alkylating chemotherapy in recurrent glioblastoma

BACKGROUND

The use of alkylating chemotherapy versus bevacizumab for recurrent glioblastoma remains controversial. Here we tested the hypothesis that the activity of alkylators, but not that of bevacizumab, would be associated with the O6-methylguanine DNA methyltransferase (MGMT) promoter methylation status

PATIENTS AND METHODS

We analyzed a cohort of patients treated at centers of the German Glioma Network or the University Hospital Zurich with alkylating agent-based chemotherapy (n=260) or bevacizumab without or with irinotecan (n=84) for first recurrence of glioblastoma. Outcome was stratified for MGMT status and cross-over to bevacizumab or alkylators at further tumor progression.

RESULTS

Median post-recurrence survival-1 (PRS-1) for patients receiving alkylating agent chemotherapy at first recurrence was longer than for patients receiving bevacizumab (11.1 versus 7.4 months, p<0.001). The use of alkylating agents was associated with longer PRS-1 for patients with a methylated versus an unmethylated MGMT promoter (p=0.017). For patients receiving bevacizumab, PRS-1 was not different with or without MGMT promoter methylation. PRS-1 was longer in the group receiving alkylating chemotherapy compared to bevacizumab for patients with a methylated (p<0.001) or unmethylated MGMT promoter (p=0.034). For patients with alkylators at first recurrence receiving bevacizumab at any further recurrence, PRS-1 was longer than in patients receiving bevacizumab first and alkylators thereafter (p=0.002).

CONCLUSION

This study confirms limited value of bevacizumab in recurrent glioblastoma independent of MGMT status. Alkylating agents have activity in recurrent glioblastoma, especially in the context of a methylated MGMT promoter.

OS2.2 Chemotherapy for spinal gliomas in adults

BACKGROUND

Chemotherapy is a treatment option in patients diagnosed with anaplastic gliomas or glioblastomas of the spinal cord, or with recurrent lower graded WHO spinal gliomas that are no longer amenable to local treatment. The low incidence of spinal cord gliomas, particularly in adults, limits the ability to perform clinical trials. The role of chemotherapy in these tumors has remained unclear.

MATERIAL AND METHODS

We performed a retrospective study of 22 patients diagnosed with spinal gliomas who were treated with chemotherapy at any time during the disease course. Benefit from chemotherapy was estimated by applying Response assessment in neuro-oncology criteria. Data on radiotherapy, as well as the number of neurosurgical interventions were taken into consideration.

RESULTS

Most patients were diagnosed with astrocytoma WHO grade I-IV (N=14), the remaining patients were diagnosed with ependymoma (N=8). Median follow-up from start of chemotherapy was 92 months (95% CI, 72.6–111.4). The O6-methylguanyl-DNA-methyltransferase(MGMT)promoter methylation status was available in tumors of 12 patients: 9 tumors (75%) had an unmethylated MGMTpromoter. More than 50% of the patients had more than one neurosurgical intervention. After prior surgery 10 patients in the first-line setting had chemotherapy combined with radiotherapy, while 3 patients received chemotherapy only. The remaining 9 patients had initially received radiation therapy and chemotherapy was given at time of recurrence. In patients diagnosed with astrocytoma mainly temozolomide (TMZ) was applied (N=10), while one patient received CCNU and three patients had combination chemotherapy. Patients diagnosed with ependymoma had hydroxyurea (N=1), CCNU (N=1), TMZ (N=3) or combination chemotherapy (N=3). In the group of patients who had chemotherapy combined with radiation, response rates were as follows: anaplastic astrocytoma 3 stable diseases (SD), glioblastoma 1 complete response (CR) and 1 SD, and anaplastic ependymoma 1 SD. After chemotherapy in the group of patients previously irradiated, the following response rates were observed: 1 SD in pilocytic astrocytoma, 1 SD in diffuse astrocytoma, 3 SD in myxopapillary ependymoma, and 2 SD and 1 partial response (PR) in anaplastic ependymoma. All other patients experienced progressive disease. There was no indication for a favorable prognostic role ofMGMTpromoter methylation.

CONCLUSION

Spinal cord gliomas represent a heterogeneous group of tumors. Survival outcomes in response to chemotherapy in adult spinal glioma patients vary substantially, but individual patients appear to derive benefit from chemotherapy.

H2 Kinetic Isotope Fractionation Superimposed by Equilibrium Isotope Fractionation During Hydrogenase Activity of D. vulgaris Strain Miyazaki

We determined ²H stable isotope fractionation at natural abundances associated with hydrogenase activity by whole cells of Desulfovibrio vulgaris strain Miyazaki F expressing a NiFe(Se) hydrogenase. Inhibition of sulfate reduction by molybdate inhibited the overall oxidation of hydrogen but still facilitated an equilibrium isotope exchange reaction with water. The theoretical equilibrium isotope exchange δ²H-values of the chemical exchange reaction were identical to the hydrogenase reaction, as confirmed using three isotopically different waters with δ²H-values of – 62, +461, and + 1533‰. Expected kinetic isotope fractionation of hydrogen oxidation by non-inhibited cells was also superimposed by an equilibrium isotope exchange. The isotope effects were solely catalyzed biotically as hydrogen isotope signatures did not change in control experiments without cells of D. vulgaris Miyazaki.

The evaluation and brain representation of pleasant touch in chronic and subacute back pain

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Chronic back pain (CBP) showed less positive evaluations of touch.

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Highest response to pleasant touch in SI and SII and insula in chronic back pain.

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Highest response to pleasant touch in ventral striatum in subacute back pain (SABP).

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Correlations of brain responses with pain interference in CBP and distress in SABP.

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Brain-behavior changes in pleasant touch processing may be a marker of pain chronicity.

If touch is perceived as pleasant, it can counteract the experience of pain. However, its pain-inhibitory function might be disturbed in chronic pain and this could contribute to pain-related interference. We investigated the perception of pleasant touch and its brain correlates in chronic back pain patients (CBP) compared to subacute back pain patients (SABP) and healthy controls (HC) using soft brush strokes. CBP showed less positive evaluations of touch. We found the highest activation in somatosensory and insular cortices in CBP, ventral striatum (VS) in SABP, and the orbitofrontal cortex in HC. Brain responses were significantly positively correlated with pleasantness ratings in HC and SABP, but not CBP. Further, the insula responses in CBP were positively correlated with pain-related interference and the VS activation in SABP correlated negatively with affective distress. Brain and behavioral changes in the processing of touch and its pleasantness may be a marker of pain chronicity and raise questions about the therapeutic value of pleasant touch in pain prevention and treatment.

New perspectives on the roles of pyrimidines in the central nervous system

Since 1956, when exogenous uridine and cytidine were found to be necessary for the maintenance of perfused rat brain function, the co-existence of de novo synthesis, salvage pathways and removal of pyrimidine bases in the CNS has been a controversial subject. Here, we review studies on metabolites and enzymes of pyrimidine metabolism through more than 60 years. In view of known and newly-described inherited pyrimidine and purine disorders - some with complex clinical profiles of neurological impairments - we underline the necessity to investigate how the different pathways work together in the developing brain and then sustain plasticity, regeneration and neuro-transmission in the adult CNS. Experimentally, early incorporation studies in animal brain slices and homogenates with radio-labelled nucleosides or precursors demonstrated salvage activity or de novo synthesis. Later, the nucleoside transporters and organic anionic transporters underlying uptake of metabolites and anti-pyrimidine drugs in the CNS were identified. Recently, the expression of de novo enzymes in glial cells and neurons was verified using (immuno) histochemical and in-situ-hybridization techniques. Adult brain was shown to take up or produce all pyrimidine (deoxy) ribonucleosides or, after uptake and phosphorolysis of nucleosides, to make use of ribose for different purposes, including energy. More recently, non-canonical pyrimidine bases (5mC, 5hmC) have been found most notably in brain, pointing to considerable postreplicative DNA metabolism, with the need for pyrimidine-specific enzymes. Even more perspectives are emerging, with advances in genome analysis and in the manipulation of expression from the gene.

Iodine excretion during stimulation with rhTSH in differentiated thyroid carcinoma

Aim: Elevated iodine intake is a serious problem in the diagnostic and therapeutic application of 131iodine in patients with differentiated thyroid cancer. Therefore, iodine avoidance is necessary 3 months in advance. Additionally, endogenous stimulation requires withdrawal of thyroid hormone substitution for 4 weeks. Exogenous stimulation using recombinant human TSH (rhTSH) enables the continuous substitution of levothyroxine, which contains 65.4% of its molecular weight in iodine. Thus, a substantial source of iodine intake is maintained during exogenous stimulation. Although this amount of stable iodine is comparable to the iodine intake in regions of normal iodine supply, it may reduce the accumulation of radioiodine in thyroid carcinoma tissue. The aim of this study was to assess the iodine excretion depending on different ways of stimulation. Methods: Iodine excretion was measured in 146 patients in the long term follow up after differentiated thyroid carcinoma. Patients were separated into 2 groups, those on hormone withdrawal (G I) and rhTSH-stimulated patients on hormone substitution (G II). Results: Iodine excretion was significantly lower in hypothyroid patients (G I, median 50 μg/l, range: 25-600 μg/l) than in those under levothyroxine medication (G II, median 75 μg/l, 25-600 μg/l, p <0.027). TSH in G I (median 57.0 μU/ml, range: 14.4-183 μU/ml) was significantly lower (p <0.001) than in G II (117 μU/ml, 32.2-281 μU/ml). Conclusion: Iodine excretion was higher in patients under rhTSH-stimulation than after hormone withdrawal. This may indicate an increased iodine pool in rhTSH-stimulated patients (deiodination of levothyroxine), thus limiting the sensitivity of radioio-dine scanning to the level of endogenous stimulation despite significantly higher TSH levels during rhTSH-stimulation.

Malignant melanoma and 18F-FDG-PET: Should the whole body scan include the legs?

Aim: 18F-FDG-PET (FDG-PET) is established in staging and follow-up of malignant melanoma. The legs are affected in 10-40% at time of diagnosis even if the primary is at the arms and torso. Imaging including the legs may detect distant manifestations but increases duration of the scan by ~30 min. We intended to disclose the diagnostic benefit of scanning the legs and to evaluate the therapeutic benefit resulting. Patients, Methods: In this retrospective analyse 213 consecutive PET studies of 153 patients with suspected or recent malignant melanoma were re-evaluated for metastastic spread by a blinded investigator. Histopathological follow-up was assessed for confirmation. Results: Suspicious findings at the legs were depicted in 53 patients on 76 occasions. 38/53 showed pathologic uptake in the torso as well. In 15/53 patients it was restricted to the legs. One of them had a hitherto unknown, clinically relevant finding that was not apparent in palpation and inspection. In 6 other patients with primary location at the legs a validation of the positive PET findings was not possible up to now. Conclusion: Metastases and local recurrence of malignant melanoma at the legs were found in 41% of women and 27% of men. However, a long scan does not yield relevant additional data. We found isolated new manifestations at the legs in only 1/153 patients. We recommend performing a long scan only in patients with previous melanoma manifestations restricted to the legs. In all other cases a short scan of the torso and proximal thighs is sufficient. This allows a higher number of PET-scans without loss of diagnostic power and a shorter examination time.

Assessing Suffering in Experimental Pain Models

Abstract. Although suffering is a central issue in pain, there is only little research on this topic. The aim of this study was to assess suffering in an experimental context using various stimulation methods and durations, and to examine which psychological or psychophysiological measures covary with pain-related suffering. Twenty-one healthy volunteers participated in two experiments in which we used tonic thermal and phasic electric stimuli with short and long stimulus durations. The participants rated pain intensity, unpleasantness, and pain-related suffering on separate visual analog scales (VAS) and completed the Pictorial Representation of Illness and Self Measure (PRISM), originally developed to assess suffering in chronic illness. We measured heart rate, skin conductance responses (SCRs), and the electromyogram (EMG) of the musculus corrugator supercilii. For both heat and electric pain, we obtained high ratings on the suffering scale confirming that suffering can be evoked in experimental pain conditions. Whereas pain intensity and unpleasantness were highly correlated, both scales were less highly related to suffering, indicating that suffering is distinct from pain intensity and unpleasantness. Higher suffering ratings were associated with more pronounced fear of pain and increased private self-consciousness. Pain-related suffering was also related to high resting heart rate, increased SCR, and decreased EMG during painful stimulation. These results offer an approach to the assessment of suffering in an experimental setting using thermal and electric pain stimulation and shed light on its psychological and psychophysiological correlates.

Orotate (orotic acid): An essential and versatile molecule

Orotate (OA) is well-known as a precursor in biosynthesis of pyrimidines; in mammals it is released from the mitochondrial dihydroorotate dehydrogenase (DHODH) for conversion to UMP by the cytoplasmic UMP synthase enzyme. OA is also a normal part of the diet, being found in milk and dairy products, and it is converted to uridine for use in the pyrimidine salvage pathway predominantly in liver, kidney and erythrocytes. Early research into nutrition identified orotate as "vitamin B13," and its use as a complex with organic cations or metal ions was promulgated in body-building, and in assisting therapies of metabolic syndromes. It has recently been established that the amelioration of gout by dairy products arises from the competition of orotate and urate at the hURAT1 transporter. The orotic aciduria that arises in children with defective UMP synthase can be rescued by oral uridine therapy, since UMP is the end-product and also a feedback inhibitor of the de novo pathway. In contrast, Miller (dysmorphology) syndrome is connected with defects in DHODH, and hence in the supply of OA, and cannot be helped by uridine. Other models of dysmorphisms are connected with enzymes early in the pyrimidine de novo pathway. We conclude that the OA molecule is itself required for the regulation of genes that are important in the development of cells, tissues and organisms.

[Enrolment of intensive care patients in clinical studies. Ethical, legal and organizational problems from an interdisciplinary point of view]

Nowadays, most patients in hospital die in the intensive care unit from sepsis and multiple organ failure. Clinical research in this critically ill and vulnerable patient population bears a lot of ethical and legal problems; however, it remains a must in order to develop evidence-based diagnostic and therapeutic strategies for life-threatening diseases with special respect to limited health care resources. With regard to the Declaration of Helsinki, good clinical practice guidelines (GCP) from the European Medicines Agency (EMA) and the German medical drug law (AMG) this article discusses ethical and legal aspects of patient inclusion for clinical trials as well as incentives for appropriate patient recruitment from an interdisciplinary point of view.

Wound fluid lactate concentration: a helpful marker for diagnosing soft-tissue infection in diabetic foot ulcers? Preliminary findings

AIMS

To investigate the impact of wound fluid lactate concentration on diagnosing soft-tissue infection in diabetic foot ulcers.

METHODS

Lactate concentration in wound fluid obtained from diabetic foot ulcers was determined using a lactate analyser and compared with clinical examination findings.

RESULTS

Overall median wound fluid lactate concentration was 21.03 mm (5.58-80.40 mm). Wound lactate levels were significantly higher in infected compared with non-infected diabetic foot ulcers (P=0.001). Non-infected diabetic foot ulcers that healed within 6 months of treatment showed a significantly lower wound fluid lactate concentration at baseline as opposed to those that did not heal (P=0.007).

CONCLUSIONS

Non-healing diabetic foot ulcers are characterized by high wound fluid lactate levels. Assessment of wound fluid lactate concentration might be helpful for confirming the suspicion of soft tissue infection, particularly when clinical signs are atypical.

Complementary therapy use in patients with glioma: an observational study

OBJECTIVE

Despite novel multimodal therapeutic approaches, the vast majority of glial tumors are not curable. Patients may search for complementary therapies in order to contribute to the fight against their disease or to relieve symptoms induced by their brain tumor. The extent of the use of complementary or alternative therapies, the patients' rationale behind it, and the cost of complementary therapy for gliomas are not known. We used a questionnaire and the database of the German Glioma Network to evaluate these questions.

METHODS

A total of 621 questionnaires were available for evaluation from patients with glial tumors of WHO grades II to grade IV. The patients were recruited from 6 neuro-oncologic centers in Germany. Complementary therapy was defined as methods or compounds not used in routine clinical practice and not scientifically evaluated.

RESULTS

Forty percent of the responding patients reported the use of complementary therapies. Significant differences between the group of complementary therapy users and nonusers were seen with respect to age (younger > older), gender (female > male), and education (high education level > low education level). The motivation for complementary therapy use was not driven by unsatisfactory clinical care by the neuro-oncologists, but by the wish to add something beneficial to the standard of care.

CONCLUSIONS

In clinical practice, patients' use of complementary therapies may be largely overseen and underestimated. The major motivation is not distrust in conventional therapies. Neuro-oncologists should be aware of this phenomenon and encourage an open but critical dialogue with their patients.

Are patients with Hodgkin lymphoma and high-grade non-Hodgkin lymphoma in clinical therapy optimization protocols representative of these groups of patients in Germany?

BACKGROUND

Improvement of lymphoma therapy is largely driven by clinical therapy optimization protocols (TOPs). It is unclear, however, whether the patients treated in clinical TOP are representative for all patients.

PATIENTS AND METHODS

TOP participants were compared with nonstudy patients in a population-based approach. The study included patients with Hodgkin lymphoma (HL) and high-grade non-Hodgkin lymphoma (hgNHL). Incident cases (N = 743) were ascertained in a large population-based epidemiologic survey. Each patient's status with respect to exclusion criteria of the pertinent TOP was abstracted from primary data sources. TOP participants were identified on the basis of the trial databases. Baseline characteristics and risk factor prevalence were compared between nonstudy and TOP patients.

RESULTS

Eligible for the respective TOPs were 64.1% of all incident HL patients and 29.6% of all hgNHL patients in the population. Main exclusion criterion was age (HL: 15.2%; hgNHL: 27.4%). Only 71 HL patients (23.0%) and 11 hgNHL patients (3.4%) had actually been enrolled in the respective TOPs.

CONCLUSIONS

TOP participants do not represent all patients with hgNHL and HL in the population. TOP inclusion criteria caused considerable selection among the participants. Further investigation is required to clarify possible limitations for the application of the outcomes observed in TOP patients for all patients with these diseases.