Psoralen and long wavelength ultraviolet radiation as an adjuvant therapy for prevention of intimal hyperplasia and constrictive remodeling after balloon dilation: a study in the rabbit iliac artery

BACKGROUND AND OBJECTIVE: Restenosis after balloon angioplasty is the summated effect of intimal hyperplasia and arterial shrinkage, both caused by hyperproliferation. In the present study, the potential of a photochemotherapeutic modality (Psoralen + UVA: PUVA) for the prevention of angioplasty induced proliferation was explored. STUDY DESIGN/MATERIALS AND METHODS: In rabbit iliac arteries, balloon dilation followed by PUVA-therapy (H = 1 J/cm2) was performed (n = 15). Contralateral arteries served as control. After 2 and 28 days of survival, the contribution of intimal hyperplasia and remodeling to lumen loss was determined by means of angiography and histological analysis. RESULTS: After 2 days, large parts of the media had become acellular, while proliferation was occurring predominantly in the adventitia in both groups. After 28 days, late loss, arterial shrinkage, but not intimal hyperplasia were larger in the PUVA group (P <0.05). CONCLUSION: PUVA-therapy did not prevent intimal hyperplasia following balloon dilation but enhanced luminal narrowing by augmented constrictive remodelin

Detection of apoptosis by optical coherence tomography (OCT)

Apoptosis is the effector of regulated cell death and plays a role in many physiologic and pathologic processes. It is characterized by a highly regulated condensation and fragmentation of the cell nucleus, a large scatterer, and breakup of the entire cell into vesicles, (apoptotic bodies) containing cell organelles and fragments of the nucleus. A two-fold increase in attenuation coefficient (μ) is observed in cell culture after chemical induction of apoptosis. An identical increase in scattering is observed in a tissue culture of porcine carotid artery, in which apoptosis is induced by balloon dilation. These observations are theoretically supported by calculations based on Mie theory. The preliminary results of this study indicate that the apoptotic process may be detected using OCT due to an increase in scattering by the typical disintegration of cellular material. The described increase in scattering may also be detected by other optical techniques

How to attract employees back to the office? A stated choice study on hybrid working preferences

It is expected that most office workers will work from home more often after COVID-19, but it remains unclear who is inclined to go back to the office and who is not when hybrid working becomes reality. Existing studies lack insights how (design) characteristics of the available office and home workspace influences workspace choice behavior. This survey-based stated choice experiment identifies two employee segments: one that intends to re-embrace the office and one that prefers to stay home a lot. Especially the expected crowdedness on the floor and availability of private spaces for concentration and meetings determined these employees’ choices. Also, the office workers segment contained relatively more male, highly educated, full-time workers with communication as an important component of their work and a short commute, while the home workers segment contained relatively more females, part-time employees, and administrative roles, plus employees with more individually focused work and a long commute

Discrimination of atherosclerotic plaque constituents based on local measurements of optical attenuation coefficients by OCT

Imaging of human autopsy samples was performed from the luminal side with a high (3.5 μm axial and 7 μm lateral) resolution OCT system (around 800 nm) or a regular (15-20 μm axial and 20 μm lateral resolution) OCT system (around 1300 nm). For each sample, dimensions were measured by histomorphometry and OCT and the optical attenuation was measured. Quantitative analysis showed a strong and significant correlation between OCT and histology cap thickness measurements for both OCT systems. For both systems, the measured attenuation coefficients of diffuse intimal thickening and lipid-rich regions differed significantly from media and calcifications. Both the high and regular resolution OCT systems can precisely image the atherosclerotic plaques. Quantitative analysis of the OCT signals allowed in situ determination of the intrinsic optical attenuation coefficient of atherosclerotic tissue components within regions of interest, which can further help to discriminate the plaque and arterial wall components

Changes in optical properties of cells and tissue after induction of apoptosis

Apoptosis is the effector of regulated cell death and plays a role in many physiologic and pathologic processes. It is characterized by a highly regulated condensation and fragmentation of the cell nucleus, and breakup of the entire cell into vesicles, (apoptotic bodies) containing cell organelles and fragments of the nucleus. Previous experiments indicate that changes in optical properties after induction of apoptosis might be detected using optical imaging systems, such as optical coherence tomography (OCT), due to an increase in scattering of apoptotic cells. The previous in vitro experiments are extended to ex vivo and in vivo experiments. A nearly two-fold increase in attenuation coefficient is observed in a tissue culture of porcine carotid artery, in which apoptosis is induced by balloon dilation, and a significant 20 % increase in an in vivo setup. The preliminary results of this study indicate that the apoptotic process may also be detected ex vivo and in vivo using optical imaging systems, such as optical coherence tomography (OCT), due to an increase in scattering by the typical disintegration of cellular material