Dietary proanthocyanidins: occurrence, dietary intake, bioavailability, and protection against cardiovascular disease

The French have one of the lowest incidences of coronary heart disease in the Western world despite a diet with a relatively high fat content. This phenomenon that has puzzled researchers worldwide for more than a decade is known as the 'French paradox' and has been linked to the high consumption of red wine in France. Red wine is rich in the complex polyphenols, the proanthocyanidins, and these compounds have recently attracted attention as potential cardiac-protective compounds. The present review summarizes the literature on proanthocyanidins with focus on their chemical structure, the occurrence, the daily intake from foods, the bioavailability and metabolism, and the evidence for a protective effect against cardiovascular diseases.     

MatLab program for precision calibration of optical tweezers

Optical tweezers are used as force transducers in many types of experiments. The force they exert in a given experiment is known only after a calibration. Computer codes that calibrate optical tweezers with high precision and reliability in the (x,y)-plane orthogonal to the laser beam axis were written in MatLab (MathWorks Inc.) and are presented here. The calibration is based on the power spectrum of the Brownian motion of a dielectric bead trapped in the tweezers. Precision is achieved by accounting for a number of factors that affect this power spectrum. First, cross-talk between channels in 2D position measurements is tested for, and eliminated if detected. Then, the Lorentzian power spectrum that results from the Einstein-Ornstein-Uhlenbeck theory, is fitted to the low-frequency part of the experimental spectrum in order to obtain an initial guess for parameters to be fitted. Finally, a more complete theory is fitted, a theory that optionally accounts for the frequency dependence of the hydrodynamic drag force and hydrodynamic interaction with a nearby cover slip, for effects of finite sampling frequency (aliasing), for effects of anti-aliasing filters in the data acquisition electronics, and for unintended “virtual” filtering caused by the position detection system. Each of these effects can be left out or included as the user prefers, with user-defined parameters. Several tests are applied to the experimental data during calibration to ensure that the data comply with the theory used for their interpretation: Independence of x- and y-coordinates, Hooke's law, exponential distribution of power spectral values, uncorrelated Gaussian scatter of residual values. Results are given with statistical errors and covariance matrix.

Program summary

Title of program: tweezercalibCatalogue identifier: ADTVProgram obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland.Program Summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTVComputer for which the program is designed and others on which it has been tested: General computer running MatLab (MathWorks Inc.).Programming language used: MatLab (MathWorks Inc.). Uses “Optimization Toolbox” and “Statistics Toolbox”.Memory required to execute with typical data: Of order 4 times the size of the data file.High speed storage required: NoneNo. of lines in distributed program, including test data, etc.: 133 183No. of bytes in distributed program, including test data, etc.: 1 043 674Distribution format: tar gzip fileNature of physical problem: Calibrate optical tweezers with precision by fitting theory to experimental power spectrum of position of bead doing Brownian motion in incompressible fluid, possibly near microscope cover slip, while trapped in optical tweezers. Thereby determine spring constant of optical trap and conversion factor for arbitrary-units-to-nanometers for detection system.Method of solution: Elimination of cross-talk between quadrant photo-diode's output channels for positions (optional). Check that distribution of recorded positions agrees with Boltzmann distribution of bead in harmonic trap. Data compression and noise reduction by blocking method applied to power spectrum. Full accounting for hydrodynamic effects: Frequency-dependent drag force and interaction with nearby cover slip (optional). Full accounting for electronic filters (optional), for “virtual filtering” caused by detection system (optional). Full accounting for aliasing caused by finite sampling rate (optional). Standard non-linear least-squares fitting. Statistical support for fit is given, with several plots suitable for inspection of consistency and quality of data and fit.Restrictions on the complexity of the problem: Data should be positions of bead doing Brownian motion while held by optical tweezers. For high precision in final results, data should be time series measured over a long time, with sufficiently high experimental sampling rate: The sampling rate should be well above the characteristic frequency of the trap, the so-called corner frequency. Thus, the sampling frequency should typically be larger than 10 kHz. The Fast Fourier Transform applied requires the time series to contain 2ⁿ data points, and long measurement time is obtained with n>12-15. Finally, the optics should be set to ensure a harmonic trapping potential in the range of positions visited by the bead. The fitting procedure checks for harmonic potential.Typical running time: (Tens of) minutesUnusual features of the program: NoneReferences: The theoretical underpinnings for the procedure are found in [K. Berg-Sørensen, H. Flyvbjerg, Rev. Sci. Instrum. 75 (3) (2004) 594].     

Improved axial position detection in optical tweezers measurements

We investigate the axial position detection of a trapped microsphere in an optical trap by using a quadrant photodiode. By replacing the photodiode with a CCD camera, we obtain detailed information on the light scattered by the microsphere. The correlation of the interference pattern with the axial position displays complex behavior with regions of positive and negative interference. By analyzing the scattered light intensity as a function of the axial position of the trapped sphere, we propose a simple method to increase the sensitivity and control the linear range of axial position detection.     

Factors Explaining Interpersonal Variation in Plasma Enterolactone Concentrations in Humans

Lignans are diphenolic plant compounds with potential health modulating properties that are absorbed to the circulation and metabolized to the enterolignans enterodiol (END) and enterolactone (ENL) by gut microbiota. Epidemiological studies have inconsistently shown that a high lignan intake and circulating ENL are associated with reduced risk of breast‐, prostate‐, and colorectal cancer as well as cardiovascular disease and total and cause‐specific mortality. Inconsistencies can be due to interpersonal variation of ENL formation or responses. The aim of this review is to identify and evaluate the impact of factors influencing variability in plasma concentrations of the main enterolignan, ENL. The main determinants of plasma ENL concentrations are intake of lignan and lignan‐rich foods, composition and activity of intestinal microflora, antimicrobial use, nutrient intake, BMI, smoking, sex, and age. Composition and activity of the intestinal microbiota appear to be the most critical factor governing interpersonal variability in plasma ENL concentration followed by the use of antibiotics. Future studies with combined data from gut microbiota and metabolomics with food intake and life style data can be used to estimate the relative contribution of the different factors to ENL concentration in quantitative terms.     

Quantitative Evaluation of the Cellular Uptake of Nanodiamonds by Monocytes and Macrophages

Fluorescent nanodiamonds (FNDs) with negative nitrogen-vacancy (NV⁻) defect centers are great probes for biosensing applications, with potential to act as biomarkers for cell differentiation. To explore this concept, uptake of FNDs (≈120 nm) by THP-1 monocytes and monocyte-derived M0-macrophages is studied. The time course analysis of FND uptake by monocytes confirms differing FND-cell interactions and a positive time-dependence. No effect on cell viability, proliferation, and differentiation potential into macrophages is observed, while cells saturated with FNDs, unload the FNDs completely by 25 cell divisions and subsequently take up a second dose effectively. FND uptake variations by THP-1 cells at early exposure-times indicate differing phagocytic capability. The cell fraction that exhibits relatively enhanced FND uptake is associated to a macrophage phenotype which derives from spontaneous monocyte differentiation. In accordance, chemical-differentiation of the THP-1 cells into M0-macrophages triggers increased and homogeneous FND uptake, depleting the fraction of cells that were non-responsive to FNDs. These observations imply that FND uptake allows for distinction between the two cell subtypes based on phagocytic capacity. Overall, FNDs demonstrate effective cell labeling of monocytes and macrophages, and are promising candidates for sensing biological processes that involve cell differentiation.     

Variations in Oncology Consultations: How Dictation Allows Variations to be Documented in Standardized Ways

In-between 2016 and 2017 a new hospital information system (HIS) was introduced at several hospitals in Denmark radically changing the core work practices for a majority of the healthcare professionals. Promptly, the new HIS began to receive criticism from healthcare professionals for failing to live up to proclaimed expectations. To fully understand the problems experienced by the healthcare professionals we need to understand the fundamental nature of the work prior to the implementation. In this paper, we investigate patient consultations as they were performed prior to the implementation of the HIS at an oncology department. Reporting from a 1.5 year-long study, we find patient consultations were organized in three sequential activities: review, interaction, and documentation. Further, we find that the dictaphone served as a key artifact allowing physicians to enact flexibility in documentation while simultaneously providing them with the capability to communicate and coordinate with the medical secretaries. Our empirical findings suggest that the medical secretaries are critical for structured documentation of variations in health data and are the cornerstones that allow physicians to enact sentimental efforts when interacting with patients. These insights prove important in understanding the criticism aimed at the new HIS implementation since the implementation removed the dictaphone as a key artifact and instead introduced a new organizational structure where documentation was assumed accomplished in parallel with patient interaction. The transformation consequently shifted work, previously performed by the medical secretaries, to the physicians.