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The small photoreceptor Photoactive Yellow Protein (PYP) enters a reversible photocycle after excitation with blue light. The intermediate states are formed on timescales ranging from femtoseconds to seconds including chromophore isomerization and protonation as well as large structural rearrangements. To obtain local dynamic information the vibrational label thiocyanate (SCN) can be inserted site-specifically at any desired position in the protein by cysteine mutation and cyanylation. The label's CN stretch vibration is highly sensitive to polarity, hydrogen bonding interactions and electric fields and is spectrally well separated from the overlapping protein absorptions. During the course of this thesis it was impressively demonstrated that the successful incorporation of the SCN label at selected positions in PYP provides a powerful tool to study structure changes and dynamics during the photocycle and enhance the local information that are obtained by infrared (IR) spectroscopic methods. Hence the SCN-labeled protein mutants were studied under equilibrium (steady-state) and non-equilibrium conditions.
Examination of the SCN absorption by FTIR spectroscopy showed the influence of various local environments on the label for different locations in the dark state. The response of the label under illumination with blue light reveals information about structural changes in the signaling state. Additional information for both states were obtained by the vibrational lifetime of the CN vibration measured via ultrafast IR-pump-IR-probe experiments. This observable is particularly sensitive for solvent exposure of the label. Time-resolved IR spectroscopy proved to be an excellent method to follow the protein dynamics throughout most part of the photocycle on a hundreds of femtoseconds to milliseconds timescale. By close inspection of protein and chromophore dynamics in wildtype-PYP over nine decades in time, new insights into the changes leading to the proposed photocycle intermediates were obtained. The investigation of the SCN label allowed to follow the different transient structure changes with high local resolution. Depending on its position within the protein the response of the label provided additional information on the photocycle transitions.
The insights that are obtained by the different observables in the steady-state and by the reaction of the SCN label to formation of the different intermediate states during the photocycle contribute to an improved understanding of local, light-induced structure changes in the photoreceptor PYP. This comprehensive study demonstrated the potential provided by the application of SCN as IR label for investigation of protein dynamics.
In solid tumors, tumor‐associated macrophages (TAMs) commonly accumulate within hypoxic areas. Adaptations to such environments evoke transcriptional changes by the hypoxia‐inducible factors (HIFs). While HIF‐1α is ubiquitously expressed, HIF‐2α appears tissue‐specific with consequences of HIF‐2α expression in TAMs only being poorly characterized. An E0771 allograft breast tumor model revealed faster tumor growth in myeloid HIF‐2α knockout (HIF‐2αLysM−/−) compared with wildtype (wt) mice. In an RNA‐sequencing approach of FACS sorted wt and HIF‐2α LysM−/− TAMs, serine protease inhibitor, Kunitz type‐1 ( Spint1) emerged as a promising candidate for HIF‐2α‐dependent regulation. We validated reduced Spint1 messenger RNA expression and concomitant Spint1 protein secretion under hypoxia in HIF‐2α‐deficient bone marrow–derived macrophages (BMDMs) compared with wt BMDMs. In line with the physiological function of Spint1 as an inhibitor of hepatocyte growth factor (HGF) activation, supernatants of hypoxic HIF‐2α knockout BMDMs, not containing Spint1, were able to release proliferative properties of inactive pro‐HGF on breast tumor cells. In contrast, hypoxic wt BMDM supernatants containing abundant Spint1 amounts failed to do so. We propose that Spint1 contributes to the tumor‐suppressive function of HIF‐2α in TAMs in breast tumor development.
Background: Patients with head and neck cancer (HNC) are at high risk for malnutrition because of tumour localisation and therapy. Prophylactic percutaneous endoscopic gastrostomy (PEG) tube placement is common practice to prevent malnutrition.
Objective: To investigate the benefits of prophylactic PEG tube placement for HNC patients in terms of the influence on patients’ nutritional status, utilisation rate, complications and to identify the predictors of PEG tube utilisation.
Methods: All consecutive HNC patients who underwent prophylactic PEG tube insertion between 1 January 2011 and 31 December 2012 prior to therapy were enrolled. The PEG tube utilisation rate, complications, the patients’ nutritional status and tumour therapy were evaluated with the help of electronic patient charts and telephone interviews.
Results: A total of 181 patients (48 female, median 67.5 years) were included. The PEG utilisation rate in the entire cohort was 91.7%. One hundred and forty‐nine patients (82.3%) used the PEG tube for total enteral nutrition, 17 patients (9.4%) for supplemental nutrition and 15 patients (8.3%) made no use of the PEG tube. Peristomal wound infections were the most common complications (40.3%) in this study. A high Nutritional Risk Screening (NRS) score prior to tube insertion was found to be independently associated with PEG utilisation. No significant weight changes were observed across the three patient subgroups.
Conclusions: The overall PEG tube utilisation rate was high in this study. However, given the high rate of infections, diligent patient selection is crucial in order to determine which patients benefit most from prophylactic PEG tube insertion.
Aim: Our aim was to analyse the diagnostic workup of hospitalised infants with symptoms of congenital cytomegalovirus (CMV) infections.
Methods: This retrospective study was carried out at the University Hospital Frankfurt, Germany, from 2008 to 2017 on infants aged 4 weeks to 12 months presenting with neurological symptoms consistent with congenital CMV infections.
Results: We studied 117 infants, and workup data for CMV infections were available for 84%. Of these, 54% were immunoglobulin G‐ and immunoglobulin M‐seronegative for CMV or immunoglobulin G‐seropositive with no viral shedding. Congenital CMV infection was excluded in these cases. In 16%, the CMV workup was incomplete, precluding a definitive diagnosis. Dried blood spots (DBS) were requested from 30%. CMV polymerase chain reaction was negative in 19 of these 29 infants, and CMV deoxyribonucleic acid detection confirmed congenital CMV infections in six patients. DBS had been destroyed in line with German law in four cases. Congenital CMV infections were diagnosed (5%) or excluded (62%) in 67% of patients and unanswered in the remaining 33%.
Conclusion: Diagnoses of congenital CMV infections were widely considered and found in 5%. CMV was not stringently investigated in all patients or remained elusive due to German law on destroying DBS.
Aims: Heart failure (HF) leads to repeat hospitalisations and reduces the duration and quality of life. Pulmonary artery pressure (PAP)‐guided HF management using the CardioMEMS™ HF system was shown to be safe and reduce HF hospitalisation (HFH) rates in New York Heart Association (NYHA) class III patients. However, these findings have not been replicated in health systems outside the United States. Therefore, the CardioMEMS European Monitoring Study for Heart Failure (MEMS‐HF) evaluated the safety, feasibility, and performance of this device in Germany, The Netherlands, and Ireland.
Methods and results: A total of 234 NYHA class III patients (68 ± 11 years, 22% female, ≥1 HFH in the preceding year) from 31 centres were implanted with a CardioMEMS sensor and underwent PAP‐guided HF management. One‐year rates of freedom from device‐ or system‐related complications and from sensor failure (co‐primary outcomes) were 98.3% [95% confidence interval (CI) 95.8–100.0] and 99.6% (95% CI 97.6–100.0), respectively. Survival rate was 86.2%. For the 12 months post‐ vs. pre‐implant, HFHs decreased by 62% (0.60 vs. 1.55 events/patient‐year; hazard ratio 0.38, 95% CI 0.31–0.48; P < 0.0001). After 12 months, mean PAP decreased by 5.1 ± 7.4 mmHg, Kansas City Cardiomyopathy Questionnaire (KCCQ) overall/clinical summary scores increased from 47.0 ± 24.0/51.2 ± 24.8 to 60.5 ± 24.3/62.4 ± 24.1 (P < 0.0001), and the 9‐item Patient Health Questionnaire sum score improved from 8.7 ± 5.9 to 6.3 ± 5.1 (P < 0.0001).
Conclusion: Haemodynamic‐guided HF management proved feasible and safe in the health systems of Germany, The Netherlands, and Ireland. Physician‐directed treatment modifications based on remotely obtained PAP values were associated with fewer HFH, sustainable PAP decreases, marked KCCQ improvements, and remission of depressive symptoms.
Purpose: To evaluate the prevalence of peri‐implantitis (PI) and peri‐implant mucositis (PM) in a long‐term follow‐up with comparison among different PI and PM definitions, and to report on the incidence of PI.
Materials and Methods: In a retrospective clinical study five different PI and PM definitions were applied onto a population with 274 implants 17 to 23 years postimplant placement. Recommendations by the Eighth European Workshop on Periodontology (EWOP) were used as base reference. Clinical and radiological measurements were considered. Risk factors were evaluated in a regression analysis.
Results: After an average observation period of 18.9 years, 40.1% of the implants were diagnosed with PM and 15.0% with PI (Eighth EWOP). PI incidence reached 7.9% on implant level and 13.2% on patient level. Implants diagnosed with PI and progressive bone loss displayed exceptionally vertical bone defect configuration (BDC). Diabetes mellitus, smoking, regular maintenance, or a former periodontal infection did not show significant influence on the prevalence of peri‐implant diseases. Patients with bruxism displayed significantly less PM and PI.
Conclusions: Vertical BDC seems to correspond with active PI, wherefore we estimate such a defining factor of importance. Diagnosis of PM and evaluation of probing pocket depths might be only of descriptive interest as they could lead to false‐positive results.
Paul Ehrlich's concept of the magic bullet, by which a single drug induces pharmacological effects by interacting with a single receptor has been a strong driving force in pharmacology for a century. It is continually thwarted, though, by the fact that the treated organism is highly dynamic and the target molecule(s) is (are) never static. In this article, we address some of the factors that modify and cause the mobility and plasticity of drug targets and their interactions with ligands and discuss how these can lead to unexpected (lack of) effects of drugs. These factors include genetic, epigenetic, and phenotypic variability, cellular plasticity, chronobiological rhythms, time, age and disease resolution, sex, drug metabolism, and distribution. We emphasize four existing approaches that can be taken, either singly or in combination, to try to minimize effects of pharmacological plasticity. These are firstly, to enhance specificity using target conditions close to those in diseases, secondly, by simultaneously or thirdly, sequentially aiming at multiple targets, and fourthly, in synchronization with concurrent dietary, psychological, training, and biorhythm‐synchronizing procedures to optimize drug therapy.
Objective: To compare discomfort/pain following periodontal probing around teeth and peri‐implant probing around implants with or without platform switching.
Methods: Two dentists recruited and examined 65 patients, each of them exhibiting a dental implant with a contralateral tooth. Only two types of implants were included: one with and one without platform switching. Periodontal and peri‐implant probing depths (PPD) and probing attachment level (PAL) were assessed. Whether implant or tooth was measured first was randomly assigned. Immediately after probing, patients scored discomfort/pain using a visual analogue scale (VAS). The emergence profiles of implant crowns were assessed as angles between interproximal surfaces on radiographs.
Results: Sixty‐five patients (age 69; 63/76 years [median; lower/upper quartile]; 38 females, 11 smokers) were examined. With the exception of mean PPD and PAL (p < .05) clinical parameters (PPD, PAL, bleeding on probing, suppuration) were well balanced between implants and teeth. Peri‐implant probing (VAS: 10; 0.75/16.25) caused significantly (p < .001) more discomfort/pain than periodontal probing (4; 0/10). Logistic regression analysis identified a larger difference between discomfort/pain for peri‐implant and periodontal probing in the maxilla than the mandible (p = .003). Comparing discomfort/pain between implants maxilla (p = .006) and emergence profile (p = .015) were associated with discomfort/pain. Type of implant (with/without platform switching) had no significant effect on discomfort/pain.
Conclusions: Peri‐implant probing caused significantly more discomfort/pain than periodontal probing. Implant design with/without platform switching failed to have a significant effect on discomfort/pain.