Establishing a Comprehensive Toolbox for Isotopic Labelling Studies on Terpene Synthases

The cumulative doctoral thesis "Establishing a Comprehensive Toolbox for Isotopic Labelling Studies on Terpene Synthases" describes the synthesis and application of isotopically labelled compounds for the systematic in vitro investigation of recombinant terpene synthases to target both cyclisation mechanism and product structure. Methodically, the known approach of enantioselectively deuterated oligoprenyl diphosphate substrates was further developed by the addition of 13C-labelling, which led to a more sensitive detection of the labelled product by NMR. With a stereochemical anchor of known absolute configuration installed in the substrate and untouched by the enzymatic cyclisation mechanism, it is possible to infer the absolute configuration of the terpene product by following the incorporation of deuterium into the diastereotopic hydrogen positions. By combining chemical and enzymatic synthesis, it was finally possible to label every methylene group of the common terpene precursors by 13C and 2H in an enantioselective fashion. These extensions improve both feasibility and robustness of this method, which contributes to the challenging structure elucidation of terpene natural products, including their difficult to address absolute configurations. Depending on the cyclisation mechanism, also the stereochemical course of hydrogen movements can be delineated. Connected to the expanding labelling possibilities, several newly identified terpene synthases from bacteria and fungi have been addressed covering various aspects of their catalysis such as substrate or product specificity, repetitive mechanistic motifs and stereochemical issues. The structural variety of the known and newly identified natural products thereby inspired further studies like tailored labelling experiments, site-directed mutagenesis, chemical modifications and the investigation of EI-MS fragmentation mechanisms. With few publications dealing with other aspects of natural product chemistry such as fungal aromatic volatiles, lignin degradation and selected aspects of the secondary metabolism of marine Roseobacter group bacteria also being included in this work, the main focus lays on a deepened understanding of terpene synthase reactions. The isotopically labelled substrates introduced in this study thereby represent a valuable experimental tool towards a comprehensive picture of these astonishing enzymes that create the largest group of natural products

Relationship between vasospasm, cerebral perfusion, and delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

Vasospasm after aneurysmal subarachnoid hemorrhage (SAH) is thought to cause ischemia. To evaluate the contribution of vasospasm to delayed cerebral ischemia (DCI), we investigated the effect of vasospasm on cerebral perfusion and the relationship of vasospasm with DCI. We studied 37 consecutive SAH patients with CT angiography (CTA) and CT perfusion (CTP) on admission and within 14 days after admission or at time of clinical deterioration. CTP values (cerebral blood volume, cerebral blood flow (CBF) and mean transit time), degree of vasospasm on CTA, and occurrence of DCI were recorded. Vasospasm was categorized as follows: no spasm (0-25% decrease in vessel diameter), moderate spasm (25-50% decrease), and severe spasm (> 50% decrease). The correspondence of the flow territory of the most spastic vessel with the least perfused region was evaluated, and differences in perfusion values and occurrence of DCI between degrees of vasospasm were calculated with 95% confidence intervals (95% CI). Fourteen patients had no vasospasm, 16 were moderate, and seven were severe. In 65% of patients with spasm, the flow territory of the most spastic vessel corresponded with the least perfused region. There was significant CBF (milliliters per 100 g per minute) difference (-21.3; 95% CI, -37 a dagger"aEuro parts per thousand a'5.3) between flow territories of severe and no vasospasm. Four of seven patients with severe, six of 16 with moderate, and three of 14 patients with no vasospasm had DCI. Vasospasm decreases cerebral perfusion, but corresponds with the least perfused region in only two thirds of our patients. Furthermore, almost half of patients with severe vasospasm do not have DCI. Thus, although severe vasospasm can decrease perfusion, it may not result in DCI

К вопросу совершенствования технологии управления процессами воздухораспределения и газовыделения на выемочных участках

Розглянуто процес розвитку технологічних схем провітрювання та дегазації виймальних ділянок вугільних шахт. Показане, що вакуумування і відвід по трубопроводу притоків газоповітряної суміші з верхньої частини лави за межі виймальної дільниці відкриває можливість впливати на аеродинамічний процес одночасно у двох напрямках – у керуванні газовиділенням і повітрерозподілом. Вплив такого впливу розглянуте в умовах основних застосовуваних схем провітрювання.The process of technological schemes of ventilation and drainage excavation sites of coal mines. Shown that the evacuation and removal via tributaries of gas-air mixture from the top of the long wall beyond excavation site provides an opportunity to influence the aerodynamic processes in two directions - in the management of any gas and air distribution. The effect of such exposure is considered in terms of the basic circuits used airing

Genome-wide linkage analysis combined with genome sequencing in large families with intracranial aneurysms

Rupture of an intracranial aneurysm (IA) leads to aneurysmal subarachnoid haemorrhage (ASAH), a severe type of stroke. Some rare variants that cause IA in families have been identified, but still, the majority of genetic causes, as well as the biological mechanisms of IA development and rupture, remain unknown. We aimed to identify rare, damaging variants for IA in three large Dutch families with multiple affected members with IA (N = 9, 11, and 6). By combining linkage analysis and genome sequencing (GS), we identified six rare and damaging variants for which all cases within one of the families were heterozygous. These variants were p.Tyr87Cys in SYCP1, p.Phe1077Leu in FMNL2, p.Thr754Lys in TBC1D2, p.Arg321His in ZNF782, p.Arg979Trp in CCDC180, and p.Val125Met in NCBP1. None of the variants showed association with IA status in a large cohort of 937 patients from the general IA patient population and 1046 controls. Gene expression in IA and cerebral artery tissue further prioritized FMNL2 and TBC1D2 as potential important players in IA pathophysiology. Further studies are needed to characterize the functional consequences of the identified variants and their role in the biological mechanisms of IA

Analysis of aneurysmal subarachnoid hemorrhage as a multistep process

Background and purpose: Aneurysmal subarachnoid hemorrhage (ASAH) is a complex disease with higher incidence in women compared to men and in Japan compared to other countries. It was hypothesized that ASAH is consistent with a multistep model of disease. The following assessments were made: (1) the number of steps needed for the disease to occur and (2) whether this number may be different in female versus male and in Japanese versus non-Japanese patients. Methods: Incidence data were generated from a meta-analysis on ASAH incidence until 2017, which was supplemented with a literature search from 2017 to April 2023. Age- and sex-adjusted incidences per 10-year age groups were calculated and the logarithm of age-specific incidence against the logarithm of age was regressed with least-squares regression. Results: In 2317 ASAH patients a linear relationship between logarithm of incidence and logarithm of age was found with a slope estimate of 3.13 (95% confidence interval 2.60–3.65), consistent with a four-step process. Similar estimates were found for female, male, Japanese and non-Japanese patients. Conclusions: Our results suggest that ASAH is a four-step process, also in subgroups with higher ASAH incidence. Elucidation of the exact nature of these steps can provide important clues for identification of disease mechanisms underlying ASAH

Slow recruitment in the HIMALAIA study:lessons for future clinical trials in patients with delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage based on feasibility data

Background : Our randomized clinical trial on induced hypertension in patients with delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH) was halted prematurely due to unexpected slow recruitment rates. This raised new questions regarding recruitment feasibility. As our trial can therefore be seen as a feasibility trial, we assessed the reasons for the slow recruitment, aiming to facilitate the design of future randomized trials in aSAH patients with DCI or other critically ill patient categories. Methods : Efficiency of recruitment and factors influencing recruitment were evaluated, based on the patient flow in the two centers that admitted most patients during the study period. We collected numbers of patients who were screened for eligibility, provided informed consent, and developed DCI and who eventually were randomized. Results : Of the 862 aSAH patients admitted in the two centers during the course of the trial, 479 (56%) were eligible for trial participation of whom 404 (84%) were asked for informed consent. Of these, 188 (47%) provided informed consent, of whom 50 (27%) developed DCI. Of these 50 patients, 12 (24%) could not be randomized due to a logistic problem or a contraindication for induced hypertension emerging at the time of randomization, and four (8%) were missed for randomization. Eventually, 34 patients were randomized and received intervention or control treatment. Conclusions : Enrolling patients in a randomized trial on a treatment strategy for DCI proved unfeasible: only 1 out of 25 admitted and 1 out of 14 eligible patients could eventually be randomized. These rates, caused by a large proportion of ineligible patients, a small proportion of patients providing informed consent, and a large proportion of patients with contraindications for treatment, can be used to make sample size calculations for future randomized trials in DCI or otherwise critically ill patients. Facilitating informed consent through improved provision of information on risks, possible benefits, and study procedures may result in improved enrolment

Characterization of multifunctional β-NaEuF4/NaGdF4 core–shell nanoparticles with narrow size distribution

We characterized NaEuF4/NaGdF4 core–shell nanoparticles

Relationship between videofluoroscopic and subjective (physician- and patient- rated) assessment of late swallowing dysfunction after (chemo) radiation:Results of a prospective observational study

BACKGROUND AND PURPOSE: Primary (chemo)radiation (CHRT) for HNC may lead to late dysphagia. The purpose of this study was to assess the pattern of swallowing disorders based on prospectively collected objective videofluoroscopic (VF) assessment and to assess the correlations between VF findings and subjective (physician- and patient-rated) swallowing measures. MATERIAL AND METHODS: 189 consecutive HNC patients receiving (CH)RT were included. Swallowing evaluation at baseline and 6 months after treatment (T6) encompassed: CTCAE v.4.0 scores (aspiration/dysphagia), PROMs: SWAL QOL/ EORTC QLQ-H&N35 (swallowing domain) questionnaires and VF evaluation: Penetration Aspiration Scale, semi-quantitative swallowing pathophysiology evaluation, temporal measures and oral/pharyngeal residue quantification. Aspiration specific PROMs (aPROMs) were selected. Correlations between late penetration/aspiration (PA_T6) and: clinical factors, CTCAE and aPROMs were assessed using uni- and multivariable analysis. RESULTS: Prevalence of PA increased from 20% at baseline to 43% after treatment (p<0.001).The most relevant baseline predictors for PA_T6 were: PA_T0, age, disease stage III-IV, bilateral RT and baseline aPROM 'Choking when drinking' (AUC: 0.84). In general aPROMs correlated better with VF-based PA than CTCAE scores. The most of physiological swallowing components significantly correlated and predictive for PA (i.e. Laryngeal Vestibular Closure, Laryngeal Elevation and Pharyngeal Contraction) were prone to radiation damage. CONCLUSION: The risk of RT-induced PA is substantial. Presented prediction models for late penetration/aspiration may support patient selection for baseline and follow-up VF examination. Furthermore, all aspiration related OARs involved in aforementioned swallowing components should be addressed in swallowing sparing strategies. The dose to these structures as well as baseline PROMs should be included in future NTCP models for aspiration

Long-term MRA follow-up after coiling of intracranial aneurysms: impact on mood and anxiety

Magnetic resonance angiography (MRA) screening for recurrence of a coiled intracranial aneurysm and formation of new aneurysms long-term after coiling may induce anxiety and depression. In coiled patients, we evaluated effects on mood and level of anxiety from long-term follow-up MRA in comparison to general population norms. Of 162 patients participating in a long-term (> 4.5 years) MRA follow-up after coiling, 120 completed the EQ-5D questionnaire, a visual analog health scale and a self-developed screening related questionnaire at the time of MRA. Three months later, the same questionnaires were completed by 100 of these 120 patients. Results were compared to general population norms adjusted for gender and age. Any problem with anxiety or depression was reported in 56 of 120 patients (47%; 95%CI38a dagger"56%) at baseline and 42 of 100 patients (42%; 95%CI32a dagger"52%) at 3 months, equally for screen-positives and -negatives. Compared to the reference population, participants scored 38% (95%CI9a dagger"67%) and 27% (95%CI4a dagger"50%) more often any problem with anxiety or depression. Three months after screening, 21% (20 of 92) of screen-negatives and 13% (one of eight) of screen-positives reported to be less afraid of subarachnoid hemorrhage (SAH) compared to before screening. One of eight screen-positives reported increased fear of SAH. Patients with coiled intracranial aneurysms participating in long-term MRA screening reported significantly more often to be anxious or depressed than a reference group. Screening did not significantly increase anxiety or depression temporarily. However, subjectively, patients did report an increase in anxiety caused by screening, which decreased after 3 months