Search

Analytical methods to evaluate the lipidome of biological samples need to provide high data quality to ensure comprehensive profiling and reliable structural elucidation. In this perspective, liquid chromatography-high resolution mass spectrometry (LC-HRMS) is the state-of-the-art technique for lipidomic analysis of biological samples. There are thousands of lipids in most biological samples, and therefore separation methods before introduction to the mass spectrometer is key for relative quantitation and identification. Chromatographic methods differ across laboratories, without any consensus on the best methodologies. Therefore, we designed an experiment to determine the optimal LC methodology, and assessed the value of ion mobility for an additional dimension of separation. To apply an untargeted method for hypothesis generation focused on lipidomics, LC-HRMS parameters were optimized based on the measurement of 50 panel lipids covering key human metabolic pathways. Reversed-phase liquid chromatography columns were compared based on a quality scoring system considering the signal-to-noise ratio, peak shape, and retention factor. Furthermore, drift tube ion mobility spectrometry (DTIMS) was implemented to increase peak capacity and confidence during annotation by providing collision cross section (CCS) values for the analytes under investigation. However, hyphenating DTIMS to LC-HRMS may result in a reduced sensitivity due to impaired duty cycles. To increase the signal intensity, a Box-Behnken design (BBD) was used to optimize four key factors, i.e. drift entrance voltage, drift exit voltage, rear funnel entrance, and rear funnel exit voltages. Application of a maximized desirability function provided voltages for the above-mentioned parameters resulting in higher signal intensity compared to each combination of parameters used during the BBD. In addition, the influence of single pulse and Hadamard 4-bit multiplexed modes on signal intensity was explored and different trap filling and release times of ions were evaluated. The optimized LC-DTIM-HRMS platform was applied to extracts from HepaRG cells and resulted in 3912 high-quality features (<30% median relative standard deviation; n = 6, t = 24 h). From these features, 436 lipid species could be annotated (i.e., matching based on accurate mass <5 ppm, isotopic pattern, in-silico MS/MS fragmentation, and in-silico CCS database matching <3%). The application of LC-DTIM-HRMS for untargeted analysis workflows is growing and the platform optimization, as described here, can be used to guide the method development and CCS database comparison for high confidence lipid annotation., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objective: Treatment of depression should result in the absence of symptoms, i.e. remission, in order to restore the functional status of the patient and reduce the risk for relapse. The study assessed the current remission rates in primary care and determined the influencing factors., Methods: 10 consecutive depressive patients treated by antidepressants for at least 3 months and not more than 12 months were screened by each investigator. Remission rates were defined using the Hamilton-Depression scale 7 items (score of 3 or less) as well as the Carroll self rating scale (score of 7 or less). In addition, patients completed the Sheehan Disability Scale (SDS). Initial severity of depression, type of treatment and socio-economic factors were collected., Results: 292 general practitioners screened a total of 2630 patients. Results indicated low remission rates: 28.3% according to the clinician and 17.1% according to the patient. Absence of remission was associated with higher impairment in work, social and family life. The most frequently reported residual symptoms in nonremitters were general somatic symptoms (92%), depressed mood (92%), psychic anxiety (91%) and impaired work and activities (89%). No differences were observed in remission rates between men and women. Remission rates were significantly lower in patients living alone as compared to those living in couple or family (25.1% vs 30.2%, p=0.03), in patients with lower education (21.3% vs 32.3%, p<0.001), in patients speaking French as compared to Dutch (24.0% vs 34.0% p<0.001), and unemployed patients compared to patients having an occupation (17.1% vs 39.0%, p<0.001). Higher initial severity and number of previous episodes decreased remission rates (p<0.001)., Conclusion: This study shows low remission rates in depressed patients treated in general practice. The absence of remission is associated with impairment in work, social and family life. Special attention should be given to identify patients who do not reach remission.

Rationale: To assess the success rate of smoking cessation with the "minimal intervention strategy" in general practice, and to determine the influence of spirometry on this success rate., Methods: Training in smoking cessation advice was given to 16 general practitioners (GPs). During 12 weeks, these GPs screened their practice population for smoking habits, the degree of dependence on nicotine, and the motivation to quit smoking. Patients willing to stop were randomised to a group that underwent a single office spirometry, or to a control group. The GPs were asked to support the attempts with the minimal intervention strategy. Success rates were compared after 6, 12 and 24 months., Results: On a population of 5590 patients, 1206 smokers were identified (22%). To the vulnerable group, identified following the Prochaska and Di Clemente scheme, the proposal was made to change smoking behaviour. Two hundred and twenty-one patients undertook an attempt of smoking cessation. Nicotine replacement therapy (NRT) or bupropion was prescribed in 51% of the attempts. Sixty-four sustained quitters were counted after 6 months (29%), 43 after 1 year (19%) and 33 after 2 years (15%). We found a small but statistically non-significant difference in success rate in favour of the group that underwent office spirometry., Conclusion: GPs can motivate almost 20% of their smoking population to quit smoking. The success rate with the minimal intervention strategy was 19% after 1 year and 15% after 2 years. We found no arguments in favour of confronting smokers with their lung function as a tool for enhancing smoking cessation.

Objective: To study the diagnostic parameters of a number of instruments for a diagnosis of dementia in general practice and the added diagnostic value of these tests., Study Design and Setting: Cross-sectional diagnostic research in general practice., Participants: 152 persons aged 65 plus. The Mini-Mental State Examination (MMSE), the Clock Drawing Test, the ADMP scale, the Timed Up and Go Test, the Extrapyramidal Sign Scale, the Behavior Observation Scale, the Poon-Baro-Wens computer battery, and the Cognitive Drug Research Computerized Assessment System were evaluated against the Dutch version of the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX-N). Diagnostic characteristics were calculated with their 95% CI. Using forward stepwise logistic regression analysis, a model was built with CAMDEX-N as the dependent variable and the tests under study as independent variables. Area under the curve was the main parameter for the comparisons., Results: The main diagnostic gain results from age and ADMP, followed by the Clock Drawing Test. Subsequent addition of the MMSE and computer tests results in modest additional gain only. The final model including five tests has an area under the curve of 0.95., Conclusion: Sophisticated neuropsychological computerized tests have little added value in the diagnostic work-up of dementia in general practice. Basic clinical tests used in an appropriate sequence can be very valuable in establishing the diagnosis of dementia.

Study Objectives: To determine if spirometry is essential for the early detection of COPD in general practice, compared to the screening value of a short questionnaire., Methods: A prospective survey of the population aged 35 to 70 years visiting their general practitioner (GP) during a 12-week period, using a questionnaire on symptoms of obstructive lung disease (OLD). Spirometry was performed in all participants with positive answers and in a 10% random sample from the group without complaints. Twenty GPs were provided with a hand-held spirometer, and received training in performance and interpretation of lung function tests. All 35- to 70-year-old patients (n = 3,408) were screened for current use of bronchodilators. The subgroup receiving bronchodilators (n = 250, 7%) was assumed to have OLD, and was excluded. Airflow obstruction was defined according to the European Respiratory Society standards., Results: The positive predictive power of the questionnaire was low (sensitivity, 58%; specificity, 78%; likelihood ratio, 2.6). One hundred twenty-six cases of formerly unknown OLD were detected in the group of patients with complaints, vs an extrapolated number of 90 in the group without complaints. Despite a negative predictive value of 95% for the questionnaire used, 42% of the newly diagnosed cases of OLD would not have been detected without spirometry., Conclusions: The use of a spirometer is mandatory if early stages of OLD are to be detected in general practice. Screening for airflow obstruction almost doubles the number of known patients with OLD.