Epidemiology and impact of frailty in patients with atrial fibrillation in Europe

BACKGROUND

Frailty is a medical syndrome characterised by reduced physiological reserve and increased vulnerability to stressors. Data regarding the relationship between frailty and atrial fibrillation (AF) are still inconsistent.

OBJECTIVES

We aim to perform a comprehensive evaluation of frailty in a large European cohort of AF patients.

METHODS

A 40-item frailty index (FI) was built according to the accumulation of deficits model in the AF patients enrolled in the ESC-EHRA EORP-AF General Long-Term Registry. Association of baseline characteristics, clinical management, quality of life, healthcare resources use and risk of outcomes with frailty was examined.

RESULTS

Among 10,177 patients [mean age (standard deviation) 69.0 (11.4) years, 4,103 (40.3%) females], 6,066 (59.6%) were pre-frail and 2,172 (21.3%) were frail, whereas only 1,939 (19.1%) were considered robust. Baseline thromboembolic and bleeding risks were independently associated with increasing FI. Frail patients with AF were less likely to be treated with oral anticoagulants (OACs) (odds ratio 0.70, 95% confidence interval 0.55-0.89), especially with non-vitamin K antagonist OACs and managed with a rhythm control strategy, compared with robust patients. Increasing frailty was associated with a higher risk for all outcomes examined, with a non-linear exponential relationship. The use of OAC was associated with a lower risk of outcomes, except in patients with very/extremely high frailty.

CONCLUSIONS

In this large cohort of AF patients, there was a high burden of frailty, influencing clinical management and risk of adverse outcomes. The clinical benefit of OAC is maintained in patients with high frailty, but not in very high/extremely frail ones.

Contemporary management of patients with atrial fibrillation in the Netherlands and Belgium: a report from the EORP-AF long-term general registry

BACKGROUND

Contemporary data regarding the characteristics, treatment and outcomes of patients with atrial fibrillation (AF) are needed. We aimed to assess these data and guideline adherence in the EURObservational Research Programme on Atrial Fibrillation (EORP-AF) long-term general registry.

METHODS

We analysed 967 patients from the EORP-AF long-term general registry included in the Netherlands and Belgium from 2013 to 2016. Baseline and 1‑year follow-up data were gathered.

RESULTS

At baseline, 887 patients (92%) received anticoagulant treatment. In 88 (10%) of these patients, no indication for chronic anticoagulant treatment was present. A rhythm intervention was performed or planned in 52 of these patients, meaning that the remaining 36 (41%) were anticoagulated without indication. Forty patients were not anticoagulated, even though they had an indication for chronic anticoagulation. Additionally, 63 of the 371 patients (17%) treated with a non-vitamin K antagonist oral anticoagulant (NOAC) were incorrectly dosed. In total, 50 patients (5%) were overtreated and 89 patients (9%) were undertreated. However, the occurrence of major adverse cardiac and cerebrovascular events (MACCE) was still low with 4.2% (37 patients).

CONCLUSIONS

Overtreatment and undertreatment with anticoagulants are still observable in 14% of this contemporary, West-European AF population. Still, MACCE occurred in only 4% of the patients after 1 year of follow-up.

Sparseness of the trabecular pattern on dental radiographs: visual assessment compared with semi-automated measurements

OBJECTIVE

In diagnostic imaging; human perception is the most prominent, yet least studied, source of error. A better understanding of image perception will help to improve diagnostic performance. This study focuses on the perception of coarseness of trabecular patterns on dental radiographs. Comparison of human vision with machine vision should yield knowledge on human perception.

METHOD

In a study on identifying osteoporotic patients, dental radiographs were made from 505 post-menopausal women aged 45-70 years. Intra-oral radiographs of the lower and upper jaws were made. Five observers graded the trabecular pattern as dense, sparse or mixed. The five gradings were combined into a single averaged observer score per jaw. The radiographs were scanned and a region of interest (ROI) was indicated on each. The ROIs were processed with image analysis software measuring 25 image features. Pearson correlation and multiple linear regression were used to compare the averaged observer score with the image features.

RESULTS

14 image features correlated significantly with the observer judgement for both jaws. The strongest correlation was found for the average grey value in the ROI. Other features, describing that osteoporotic patients have fewer but bigger marrow spaces than controls, correlated less with the sparseness of the trabecular pattern than a rather crude measure for structure such as the average grey value.

CONCLUSION

Human perception of the sparseness of trabecular patterns is based more on average grey values of the ROI than on geometric details within the ROI.

Minimum number of basis projections for caries detection with local CT

OBJECTIVES

To investigate the relationship between the number of basis projections for local computed tomography (CT) and the detection of proximal caries and to find a minimum number of projections needed to maintain diagnostic accuracy.

METHODS

We presented observers (n = 12) with stacks of both axial and vertical CT slices of 23 extracted teeth placed in a dry human mandible. The slices were prepared with 14, 20, 33 and 100 basis projections. The observers scored the proximal surfaces for the presence of caries on a 1-5 confidence scale. The performance of the varying number of projections was compared with conventional digital radiographs.

RESULTS

The performance of all four CT modalities was significantly better than conventional radiographs (P = 0.005 to P = 0.021) and showed a consistent increase with the number of projections. Diagnostic performance depended significantly on lesion depth (P = 0.00), but not on observer.

CONCLUSIONS

We conclude that the number of CT projections used can be reduced at least to 20 with the diagnostic performance still markedly better than that of conventional film, provided that the observer can make use of both axial and vertical stacks of CT slices.

Psychological characteristics of dissatisfied denture patients

A field study was conducted to investigate the psychological characteristics of dissatisfied denture patients using validated personality inventories. In the present study dissatisfied denture patients are patients that keep complaining about their dentures and are referred to a psychologist because it was suspected that their complaints may also be due to psychological factors. The results show that these patients feel more inhibited in their social contacts and more often have the opinion that wearing dentures is unacceptable. Also these patients are high on neuroticism, less social adequate, more rigid, have less self-esteem and are more externally oriented.

Structural elements of secretory phospholipases A2 involved in the binding to M-type receptors

Specific membrane receptors for secretory phospholipases A2 (sPLA2s) have been initially identified with novel snake venom sPLA2s called OS1 and OS2. One of these sPLA2 receptors (muscle (M)-type, 180 kDa) has a very high affinity for OS1 and OS2 and a high affinity for pancreatic and inflammatory-type mammalian sPLA2s, which might be the natural endogenous ligands of PLA2 receptors. Primary structures of OS1 and OS2 were determined and compared with sequences of other sPLA2s that bind less tightly or do not bind to the M-type receptor. In addition, the binding properties of pancreatic sPLA2 mutants to the M-type receptor have been analyzed. Residues within or close to the Ca(2+)-binding loop of pancreatic sPLA2 are crucially involved in the binding step, although the presence of Ca2+ that is essential for the enzymatic activity is not required for binding to the receptor. These residues include Gly-30 and Asp-49, which are conserved in all sPLA2s. Leu-31 is also essential for binding of pancreatic sPLA2 to its receptor. Many other mutations have been considered. Those occurring in the N-terminal alpha helices and the pancreatic loop do not change binding to the M-type receptor. Conversion of pancreatic prophospholipase to phospholipase is essential for the acquisition of binding properties to the M-type receptor.

Determinants of the inhibitory action of purified 14-kDa phospholipases A2 on cell-free prothrombinase complex

It has been suggested (Kini, R. R., and Evans, H. J. (1987) J. Biol. Chem. 262, 14402-14407) that the anticoagulant activity of members of the 14-kDa phospholipase A2 (PLA2) family depends on the presence of basic residues within a variable surface region (residues 54-77) distinct from both the conserved catalytic machinery and surface sites mediating the antibacterial action of these enzymes (see Weiss, J., Inada, M., Elsbach, P., and Crowl, R. M. (1994) J. Biol. Chem. 269, 26331-26337). To further define the determinants of the anticoagulant activity of PLA2, we have analyzed the inhibitory effects of purified native and recombinant PLA2 on cell-free prothrombinase. Both native and recombinant wild-type pig pancreas (net charge -1) and human "secretory" PLA2 (net charge +15) produced similar dose-dependent inhibition of prothrombinase activity that was significantly less potent than a toxic PLA2 purified from snake venom. Site-specific mutations that either increased or decreased PLA2 activity toward bactericidal/permeability-increasing protein-treated Escherichia coli by up to 50-fold had no effect on antiprothrombinase activity. In contrast, substitution of Arg for Asp-59/Gly for Ser-60 in the pig PLA2 increased antiprothrombinase activity by 5-10-fold without affecting catalytic activity toward a range of phospholipid substrates or antibacterial activity. Comparison of antiprothrombinase activity of catalytically active and inactive forms of the PLA2 and under a range of phospholipid conditions revealed that the potent antiprothrombinase activity of native toxic venom PLA2 and of the D59R.S60G mutant pancreatic PLA2 reflect combined catalytic and noncatalytic actions, the latter apparently dependent on basic residues at discrete surface sites in the enzyme.

Bacterial phospholipid hydrolysis enhances the destruction of Escherichia coli ingested by rabbit neutrophils. Role of cellular and extracellular phospholipases

Escherichia coli ingested by PMN are promptly growth arrested but undergo limited destruction. We have studied bacterial phospholipid hydrolysis as a possible limiting factor in the disassembly of ingested E. coli, comparing the fates, during phagocytosis by rabbit peritoneal exudate PMN, of three isogenic strains, differing in their content of the pldA gene encoding the principal E. coli phospholipase A (PLA), i.e., pldA-, pldA+, pldA (the latter strain bearing the pldA gene in a multicopy plasmid resulting in a 20-fold increase in PLA content). Ingestion and growth inhibition (greater than 99% within 15 min) were the same for the three strains, but phospholipid degradation differed according to bacterial PLA content: pldA up to 60%, pldA+ up to 30%, and pldA- up to 20%. Since the pldA- strain has no activatable PLA, phospholipid degradation in this strain demonstrates the action of a PMN PLA. Added PLA2-rich ascitic fluid (AF) or purified AF PLA2 increased the rate and extent of degradation of the pldA- strain, provided the enzyme was added before ingestion was complete. 125I-AF-PLA2 binds to both E. coli and PMN and thus can enter the vacuole during phagocytosis. Although up to 50-fold more AF-PLA2 than the PLA2 content of the PMN could be loaded into the PMN in this way, degradation of pldA- E. coli did not exceed 30%. Increased phospholipid degradation had no effect on the degradation of bacterial macromolecules. In contrast, bacterial disassembly manifest as structural disorganization, release of bacterial protein derived material, and inhibition of protein synthesis were markedly enhanced when greater than 50% of prelabelled bacterial phospholipids were degraded. These findings reveal a link between envelope phospholipid degradation and overall bacterial destruction, suggesting therefore that factors limiting PLA action limit the destruction of E. coli ingested by PMN.

The maximum rate of gene expression is dependent on the downstream context of unfavourable codons

Presented here is an experimental demonstration of our theoretical predictions on the role of the downstream context of unfavourable codons in a gene on its expression level. Six non clustered AGG codons were inserted in the chloramphenicol acetyltransferase (cat) gene of E. coli and the expression of this modified gene (cat4) was compared with that of a cat gene in which four clustered AGG codons were inserted (cat2 gene). As predicted, the rate of production of the corresponding CAT4 and CAT2 proteins is equal as long as the rate of transcription of the gene does not exceed a given limit. When this limit is exceeded, production of CAT4 continues to increase, whereas CAT2 production decreases dramatically. Various consequences and possible applications of this downstream context effect are discussed.

General method for analysing dentist-patient interaction

The interaction between dentist and patient during dental treatment may influence the frequency of dental visits in the future because this interaction may increase the dental fear of the patient. To find the characteristics of the dentist's behavior that increase or decrease dental fear a statistical analysis of the interaction may be used. Data of such interactions are known as time series. Because it is highly probable that the behavior of an individual at two different points in time is autocorrelated a correct statistical analysis of the interaction between dentist and patient must take this possibility into account. A general statistical method is proposed that can take autocorrelations into account. The method is compared with a simpler method that may not deal adequately with autocorrelations.

Site-directed mutagenesis of the COOH-terminal region of colicin A: effect on secretion and voltage-dependent channel activity

A large number of mutants introducing point mutations and deletions into the COOH-terminal domain of colicin A have been constructed by using site-directed mutagenesis. The COOH-terminal domain carries the channel activity. The effects of the alterations in the polypeptide chain on the secretion of colicin A by colicinogenic cells have been investigated. All deletions and some mutations were found to lead to protein aggregation in the cytoplasm, thereby preventing release into the medium. The mutated colicin A proteins have been purified, and their activity in vivo (on sensitive cells) and in vitro (in planar lipid bilayers) has been assayed. Deletions in the region containing putative helices 4, 5, and 6 (predicted to be involved in pore formation) and the transitions (Ala----Asp-492, Phe----Pro-493) in helix 4 abolished the activity. No correlation was observed between mutations leading to protein aggregation and those leading to loss of channel activity. Some mutations were found to alter characteristic properties of the single channels, such as stability, current-relaxation kinetics, voltage dependence, and pore conductance. Site-directed mutagenesis provides a powerful tool for studying structure-function relationships of voltage-sensitive ionic channels.