Arl2-GTP and Arl3-GTP regulate a GDI-like transport system for farnesylated cargo

Lipidated Rho and Rab GTP-binding proteins are transported between membranes in complex with solubilizing factors called 'guanine nucleotide dissociation inhibitors' (GDIs). Unloading from GDIs using GDI displacement factors (GDFs) has been proposed but remains mechanistically elusive. PDEδ is a putative solubilizing factor for several prenylated Ras-subfamily proteins. Here we report the structure of fully modified farnesylated Rheb-GDP in complex with PDEδ. The structure explains the nucleotide-independent binding of Rheb to PDEδ and the relaxed specificity of PDEδ. We demonstrate that the G proteins Arl2 and Arl3 act in a GTP-dependent manner as allosteric release factors for farnesylated cargo. We thus describe a new transport system for farnesylated G proteins involving a GDI-like molecule and an unequivocal GDF. Considering the importance of PDEδ for proper Ras and Rheb signaling, this study is instrumental in developing a new target for anticancer therapy.

Regulation of signaling at regions of cell-cell contact by endoplasmic reticulum-bound protein-tyrosine phosphatase 1B

Protein-tyrosine phosphatase 1B (PTP1B) is a ubiquitously expressed PTP that is anchored to the endoplasmic reticulum (ER). PTP1B dephosphorylates activated receptor tyrosine kinases after endocytosis, as they transit past the ER. However, PTP1B also can access some plasma membrane (PM)-bound substrates at points of cell-cell contact. To explore how PTP1B interacts with such substrates, we utilized quantitative cellular imaging approaches and mathematical modeling of protein mobility. We find that the ER network comes in close proximity to the PM at apparently specialized regions of cell-cell contact, enabling PTP1B to engage substrate(s) at these sites. Studies using PTP1B mutants show that the ER anchor plays an important role in restricting its interactions with PM substrates mainly to regions of cell-cell contact. In addition, treatment with PTP1B inhibitor leads to increased tyrosine phosphorylation of EphA2, a PTP1B substrate, specifically at regions of cell-cell contact. Collectively, our results identify PM-proximal sub-regions of the ER as important sites of cellular signaling regulation by PTP1B.

Production of IL-12 in gastritis relates to infection with Helicobacter pylori

Increased production of proinflammatory cytokines, including tumour necrosis factor-alpha (TNF-alpha), IL-1beta, IL-6 and IL-8, has been demonstrated in Helicobacter pylori-associated gastric mucosal inflammation. IL-12, a newly characterized cytokine, is thought to be a key mediator in host responses to bacterial infections. The aim of this study was to investigate differences in cytokine patterns between H. pylori-positive and -negative gastritis and normal mucosa. Secretion of IL-12, TNF-alpha, IL-1beta, IL-6, IL-8 and IL-10 was measured in 176 patients with chronic gastritis in whole biopsy cultures. Gastritis was graded for chronic inflammation or acute inflammatory activity, respectively, according to the Sydney system. Biopsies with similar scores were matched for analysis from H. pylori-infected and non-infected patients. Secretion of IL-12 was significantly increased in H. pylori-associated gastritis in comparison with H. pylori-negative gastritis (P < 0.0001). In contrast, secretion of TNF-alpha, IL-1beta, IL-6, and IL-8 correlated with the degree of inflammation but was not different between H. pylori-positive and -negative patients. Moreover, IL-10 secretion was found to be higher in H. pylori-positive than in H. pylori-negative patients. IL-12 may play a specific role in H. pylori-associated gastric disease, whereas production of the proinflammatory cytokines TNF-alpha, IL-1beta, IL-6 and IL-8 does not seem to be restricted to H. pylori-induced inflammation. The contra-inflammatory cytokine IL-10 may be a contributor to the chronicity of H. pylori-associated gastritis by impairing clearance of the pathogen.

Cell cycle-dependent binding modes of the ran exchange factor RCC1 to chromatin

The formation of an activity gradient of the small G-protein Ran around chromatin depends on the differential partitioning of the opposing enzyme activities of the Ran guanine nucleotide exchange factor RCC1 that resides on chromatin, and the cytoplasmic Ran GTPase activating protein RanGAP. We studied the time-dependent interaction kinetics between RCC1 and chromatin and the mobility of the Ran-RCC1 complex in living cells by fluorescence correlation spectroscopy to investigate whether binding of RCC1 to chromatin regulates the exchange activity of RCC1, and whether the stability of the RCC1-chromatin interaction is regulated during the cell cycle. We found that RCC1 mobility is dominated by two states: a highly mobile state that is trapped within chromatin, and a transiently immobilized state that is stabilized during mitosis. We show that only the immobilized state of RCC1 interacts with Ran and conclude that its guanine nucleotide exchange activity is restricted to specific sites on chromatin.

The socioeconomic burden of migraine: An evaluation of productivity losses due to migraine headaches based on a population study in Germany

Background

This study estimates the socioeconomic impact of migraine headaches on paid and unpaid work productivity in the adult German population in 1 year.

Methods

We used data on headache frequency (days per month) from a longitudinal population-based study. Prevalence estimates of migraine were derived from the Global Burden of Disease Collaborative Network. Demography data were derived from official statistics in 2017. Aggregate headache days in 1 year were translated to losses in paid and unpaid productive hours based on estimates of presenteeism and absenteeism along with other socioeconomic parameters. Paid hours lost were distributed across the industry sectors. In this way, an age-, gender- and industry sector-specific monetary value was calculated for paid hours lost. Unpaid hours lost were valued by assigning the unpaid activities to their nearest market substitute. In a last step, value-added multipliers derived from input-output tables were used to calculate the economic value chain effects.

Results

A total of 15.5 million persons (20 years or older) suffer from migraine in Germany. Our analysis shows that 60% of those have three or fewer headache days per month, while patients suffering chronic migraine (15+ headache days per month) account for 5.4% of the adult migraine population. Females bear 65% of the total 836 million headache days per year. The socioeconomic losses due to migraine amount to €100.4 billion (€6493 on average per patient) in one year.

Conclusion

In addition to time losses in paid work, migraine causes substantial socioeconomic losses to unpaid work activities due to its disproportionate prevalence among females. Economic value chain effects provide a novel perspective on losses beyond a patient’s time loss. Overall, the elements of socioeconomic burden provide a strong rationale that innovative migraine therapies could be of high value to society.

[Costs of delivering allogenic blood in hospitals]

INTRODUCTION

In clinical practice there are medical and economic reasons against the thoughtless use of packed red blood cells (rbc). Therefore, in searching for alternatives (therapy of anemia) the total costs of allogeneic blood transfusions must be considered. Using a practical example this article depicts the actual costs and possible alternatives from the point of view of a hospital in Germany.

METHOD

To determine the total costs of allogeneic blood transfusions the actual resource consumption associated with blood transfusions was collated and analyzed at the St. Marien-Hospital in Vechta.

RESULTS

The authors were able to show that the actual procurement costs (average. 97 EUR) represent only 55  % of the total costs of 176 EUR. The additional expenses are allocated to personnel (78  %) and materials (22  %). Alternatives, such as i.v. iron substitution or stimulation of erythropoesis might be the more economical solution especially if only purchase prices are compared and the total costs of allogeneic blood transfusions are not considered.

DISCUSSION

Analyzing a single hospital limits generalization of the results; however, in the international context the results can be recognized as plausible. So far there have been no comprehensive studies on the true costs of blood preparations, therefore, this article represents a first starting point for closing this gap by conducting additional studies.

Cost-utility analysis of dynamic intraligamentary stabilization versus early reconstruction after rupture of the anterior cruciate ligament

OBJECTIVES

The aim of this study was to evaluate the cost-effectiveness of the dynamic intraligamentary stabilization (DIS) technique in comparison with reconstructive surgery (ACLR) in the treatment of isolated anterior cruciate ligament (ACL) ruptures from the perspective of the community of insured citizens in Germany.

METHODS

Because of the specific decision problem at hand, namely that with DIS the procedure has to take place within 21 days after the initial trauma, a decision tree was developed. The time horizon of the model was set to 3 years. Input data was taken from official tariffs, payer data, the literature and assumptions based on expert opinion when necessary.

RESULTS

The decision tree analysis identified the DIS strategy as the superior one with 2.34 QALY versus 2.26 QALY for the ACLR branch. The higher QALY also came with higher costs of 5,398.05 € for the DIS branch versus 4,632.68 € for the ACLR branch respectively, leading to an ICER of 9,092.66 € per QALY. Results were robust after sensitivity analysis. Uncertainty was examined via probabilistic sensitivity analysis resulting in a slightly higher ICER of 9,567.13 € per QALY gained.

CONCLUSION

The DIS technology delivers an effective treatment for the ACL rupture at a favorable incremental cost-effectiveness ratio.

Efficacy of Retreatment After Failed Direct-acting Antiviral Therapy in Patients With HCV Genotype 1-3 Infections

Hepatitis C virus infection is causing chronic liver disease, cirrhosis, and hepatocellular carcinoma. By combining direct-acting antivirals (DAAs), high sustained virologic response rates (SVRs) can be achieved. Resistance-associated substitutions (RASs) are commonly observed after DAA failure, and especially nonstructural protein 5A (NS5A) RASs may impact retreatment options.^1-3 Data on retreatment of DAA failure patients using first-generation DAAs are limited.^4-7 Recently, a second-generation protease- and NS5A-inhibitor plus sofosbuvir (voxilaprevir/velpatasvir/sofosbuvir [VOX/VEL/SOF]) was approved for retreatment after DAA failure.⁸ However, this and other second-generation regimens are not available in many resource-limited countries or are not reimbursed by regular insurance, and recommendations regarding the selection of retreatment regimens using first-generation DAAs are very important. This study aimed to analyze patients who were re-treated with first-generation DAAs after failure of a DAA combination therapy.

Comparing the long-term clinical and economic impact of ofatumumab versus dimethyl fumarate and glatiramer acetate in patients with relapsing multiple sclerosis: A cost-consequence analysis from a societal perspective in Germany

Background

Evidence suggests that early highly efficacious therapy in relapsing multiple sclerosis is superior to escalation strategies.

Objective

A cost-consequence analysis simulated different treatment scenarios with ofatumumab (OMB), dimethyl fumarate (DMF) and glatiramer acetate (GA): immediate OMB initiation as first treatment, early switch to OMB after 1 year on DMF/GA, late switch after 5 years or no switch.

Methods

An EDSS-based Markov model with a 10-year time horizon was applied. Cycle transitions included EDSS progression, improvement or stabilization, treatment discontinuation, relapse or death. Input data were extracted from OMB trials, a network meta-analysis, published literature, and publicly available sources.

Results

The late switch compared to the immediate OMB scenario resulted in a lower proportion of patients with EDSS 0-3 (Δ - 7.5% DMF; Δ - 10.3% GA), more relapses (Δ + 0.72 DMF; Δ + 1.23 GA) and lower employment rates (Δ - 4.0% DMF; Δ - 5.6% GA). The same applies to late versus early switches. No switch scenarios resulted in worse outcomes. Higher drug acquisition costs in the immediate OMB and early switch scenarios were almost compensated by lower costs for patient care and productivity loss.

Conclusion

Immediate OMB treatment and an early switch improves clinical and productivity outcomes while remaining almost cost neutral compared to late or no switches.

[Mechanics and effects of European reference pricing for vaccines in Germany according to §130a Abs. 2 SGB V: an analysis using the example of influenza vaccines]

OBJECTIVES

On 01 January 2011 the bill for the reorganisation of the pharmaceutical market became effective. Since that time there is a European reference pricing (ERP) system for vaccines in order to bring down the German vaccine prices to an assumed lower European level. This study describes the implementation, functioning and effect of this new system. For influenza vaccines the impact of ERP on the price level and spread of prices is analysed.

METHODS

The description of the mechanism is based on the law and corresponding regulations of the head association of sickness funds (GKV-SV). The analysis of vaccine prices is based on the data of the i:data report (status of 01 September 2011) of ifap Service Institute.

RESULTS

The European reference price is calculated as the average price of the manufacturer-selling-prices of the corresponding vaccine in the 4 countries of the European Union whose gross national income comes closest to the German one and in which the vaccine is distributed. The relied prices are weighted by sales and purchasing power parities of the respective countries. This analysis suggests that in particular the practical implementation of the reference price system should be further improved and specified. The calculation of the reference prices should ensure price comparability. In addition, significant problems remain in the deduction of discounts, because no distinction is made in the documentation of vaccinating doctors, whether vaccination was performed as a compulsory or statutory benefit. The comparison of the manufacturer-selling-prices of individual influenza vaccines with the corresponding reference prices shows an enlargement of the existing price differences, which have evolved in a competitive environment, after the implementation of the reference pricing -system.

CONCLUSIONS

There is still a need for improvement in implementing the reference pricing system. In the most competitive vaccine market of influenza vaccines, the ERP-system lowers the prices, but seems to distort the market prices.

[Development and implementation of an integrated care pathway at the POLIKUM health centers using the example of anemia]

BACKGROUND

Integrated treatment pathways are an appropriate means for increasing the quality of treatment and outcome via process optimization. Taking the POLIKUM Health Centers as an example, we intend to demonstrate how the implementation can be effected for the indication of anemia.

METHOD

The development and implementation were executed by an interdisciplinary workgroup in several workshops. In addition, the diagnoses and hemoglobin values of all patients with requests for hemograms were obtained and analyzed at two locations.

RESULTS

Developing the pathway required significantly greater efforts than initially planned. The biggest challenge was to adequately map the complexity of the different forms of anemia and, concomitantly, to design a pathway that can actually be realized in everyday life. Moreover, evaluation of the patient data demonstrated that there are a large number of cases where existing anemias are not reflected in the respective diagnoses.

CONCLUSION

While the ultimate effects of the new pathway cannot yet be assessed conclusively, it was possible to obtain valuable findings for practical use even at this point. Despite the limitations of the sample, the surprisingly high number of undetected anemias should give physicians cause for taking diagnostic measures even in patients with mild anemia.

[Nuclear localization of heterochromatic regions varies in hyperplastic and preneoplastic lesions of the breast]

Previous molecular cytogenetic studies in breast cancer revealed numerous chromosomal changes and identified alterations involving the chromosomes 1 and 16 as early incidents in mammary carcinogenesis. Since both chromosomes reveal pericentromeric heterochromatic areas, these chromosomal alterations might result from instable heterochromatin caused by DNA hypomethylation. In the present study, we investigated whether hyperplastic and neoplastic lesions of the breast differ regarding the distance between the heterochromatic areas of chromosomes 1 and 16 within the nuclei. We hybridized differently fluorescence-labeled DNA samples specific for the heterochromatic regions of chromosomes 1 and 16 to formalin-fixed tissue sections. Histological classification of the lesions was supported by immunohistochemical staining using cytokeratin-specific antibodies. The methylation state of the heterochromatic regions was tested by staining with an antibody specific for methylated cytidin. Our results revealed an increased frequency of paired intranuclear signals specific for chromosomes 1 and 16 in neoplastic lesions (atypical ductal hyperplasia, ductal carcinoma in situ) compared to ductal hyperplasia and normal glandular epithelium. Staining with the methylation-specific antibody reavealed a weaker staining in neoplastic lesions compared to hyperplastic lesions and normal cells. We conclude that atypic ductal hyperplasia represents the histomorphological equivalent for the beginning of tumor genome evolution that progresses in ductal carcinoma in situ and infiltrating carcinoma.