Microscopy with ultraviolet surface excitation (MUSE): A novel approach to real‐time inexpensive slide‐free dermatopathology

Traditional histology relies on processing and physically sectioning either frozen or formalin‐fixed paraffin‐embedded (FFPE) tissue into thin slices (typically 4‐6 μm) prior to staining and viewing on a standard wide‐field microscope. Microscopy using ultraviolet (UV) surface excitation (MUSE) represents a novel alternative microscopy method that works with UV excitation using oblique cis‐illumination, which can generate high‐quality images from the cut surface of fresh or fixed tissue after brief staining, with no requirement for fixation, embedding and histological sectioning of tissue specimens. We examined its potential utility in dermatopathology. Concordance between MUSE images and hematoxylin and eosin (H&E) slides was assessed by the scoring of MUSE images on their suitability for identifying 10 selected epidermal and dermal structures obtained from minimally fixed tissue, including stratum corneum, stratum granulosum, stratum spinosum, stratum basale, nerve, vasculature, collagen and elastin, sweat glands, adipose tissue and inflammatory cells, as well as 4 cases of basal cell carcinoma and 1 case of pseudoxanthoma elasticum deparaffinized out of histology blocks. Our results indicate that MUSE can identify nearly all normal skin structures seen on routine H&E as well as some histopathologic features, and appears promising as a fast, reliable and cost‐effective diagnostic approach in dermatopathology.     

Site-directed Mutagenesis (Y52E) of POLH Affects Its Ability to Bypass Ultraviolet-induced DNA Lesions in HaCaT Cells

DNA polymerase eta (Pol η) is one of several Y family translesion synthesis (TLS) polymerases in humans and plays an important role in maintaining genome stability after ultraviolet (UV) irradiation, as it carries out error-free TLS at sites of UV-induced lesions. We performed site-directed mutagenesis of human polymerase η gene (Y52E), confirmed by sequencing, then cloned wild-type mutant and POLH genes into the eukaryotic vector pEGFP-N1. After transfecting wild-type and mutant plasmids into HaCaT keratinocytes, we tested for UV-induced cis-syn cyclobutane pyrimidine dimer (CPDs) DNA lesions, and analysed cellular viability by MTT cell proliferation assay. The results showed that CPD levels decreased with empty vector control (EVC), wild-type POLH and Y52E-POLH over 48 hours post-UV irradiation with 0.1 mW/cm2 UVB for 15 minutes (p = 0.025). The rate in CPD reduction of mutant POLH was less than in wild-type POLH. Cell viabilities of all three groups increased over 48 hours after UV irradiation, with the increased rate in the wild-type being higher than for mutant protein (p = 0.046). We conclude that Y52E POLH has reduced capacity to bypass UV-induced DNA lesions in HaCaT cells.     

Z‐ligustilide ameliorated ultraviolet B‐induced oxidative stress and inflammatory cytokine production in human keratinocytes through upregulation of Nrf2/HO‐1 and suppression of NF‐κB pathway

Ultraviolet B (UVB), a harmful environmental factor, is responsible for a variety of skin disorders including skin inflammation through reactive oxygen species (ROS) and inflammatory mediator production. Here, we investigated the effect of Z‐ligustilide (Z‐lig), an active ingredient isolated from the medicinal plants Cnidium officinale and Angelica acutiloba, on UVB‐induced ROS generation and inflammatory mediator production in normal human epidermal keratinocytes (NHEKs) as well as its underlying mechanisms. Z‐lig significantly rescued UVB‐induced NHEKs damage in a dosage‐dependent manner. Pretreatment of NHEKs with Z‐lig inhibited UVB‐induced ROS production in NHEKs. Both silencing the nuclear factor E2‐related factor 2 (Nrf2) and the supplement of tin protoporphyrin IX (SnPP), a haeme oxygenase‐1 (HO‐1) inhibitor, cancelled the inhibitory effect of Z‐lig on UVB‐induced ROS upregulation in NHEKs. Moreover, pretreatment of NHEKs with Z‐lig reduced UVB‐induced nuclear factor kappa B (NF‐κB)‐dependent inflammatory mediators (IL‐6, IL‐8 and MCP‐1) production at both mRNA and protein level. In the presence of Z‐lig, UVB‐induced NF‐κB subunit p65 nuclear translocation was abolished, and the IκBα degradation was suppressed. Taken together, these findings suggest that Z‐lig can suppress UVB‐induced ROS generation through Nrf2/HO‐1 upregulation and inflammation by suppressing the NF‐κB pathway, suggesting that Z‐lig may be beneficial in protecting skin from UVB exposure.     

Health Effects of Ultraviolet Irradiation in Asthmatic Children's Homes

Objective. Centrally installed ultraviolet (UV) irradiation units were investigated to determine the potential health benefits in mold-sensitized asthmatic children. Methods. Nineteen mold-sensitized asthmatic children 5 to 17 years of age with home central ventilation systems were enrolled in a 28-week double-blinded placebo controlled cross-over trial. Clinical outcome measurements included morning and evening peak expiratory flow rates (PEFR), PEFR variability, change in forced expiratory volume in 1 second (FEV₁), change in total rhinoconjunctivitis and asthma symptom scores, change in rhinoconjunctivitis and asthma quality-of-life scores, and total (rescue and controller) medication use from baseline and between time periods. Environmental outcomes included changes in temperature, relative humidity, dew point, and indoor airborne mold and bacterial counts from baseline and between time periods. Analysis of variance (ANOVA) and regression analysis and t test were used to evaluate relationships between environmental exposure(s) and clinical outcome measurements during each study period. Results. Twelve male and seven female children, average age 10.6 years, were enrolled. A statistically significant improvement in PEFR variability in subjects receiving CREON2000 units followed by placebo units was observed (p < 0.05) across both treatment periods. Within group analysis during treatment period 1, a statistically significant improvement in reduction of asthma symptom scores, the number of days with asthma symptoms, total asthma medication use, and PEFR variability were observed in subjects receiving CREON2000 units versus placebo units (p < 0.05). No significant differences were observed between the CREON 2000 and placebo units for other clinical or environmental outcome measurements. Conclusions. Central UV irradiation was effective at reducing airway hyperresponsiveness manifested as PEFR variability and some clinical symptoms. A larger cohort controlled longitudinal study to validate the clinical health effects of UV irradiation as a primary indoor environmental intervention for allergic asthma is necessary to confirm this finding.     

Effect of X-rays on the Duration of Life of the Rice Weevil,Sitophilus Oryzae L.

Summary

The induction of UV-type damage by ionizing radiation in repair deficient strains of E. coli is reviewed. Both photoreactivable and non-photoreactivable types of damage can be observed. The induction of UV-type damage is largely independent of the presence of free-radical reactive agents (e.g. oxygen and thiols), but is dependent upon the energy of the photon–or electron–beam used, the radiation geometry and the optical absorbance of the extracellular medium. On the basis of calculations and experimental evidence, it is clear that one mechanism whereby such damage arises is through the generation of Cerenkov emission. However, small yields of UV-type damage can be produced using X-rays whose energy is below the threshold for production of Cerenkov emission. In this instance, the damage induction mechanism is thought to involve a direct excitation process.     

Photoimmunosuppression: a brief overview

Exposure to ultraviolet radiation can lead to suppression of many adaptive immune responses, both to antigens encountered within a short period of the irradiation (primary) and to antigens previously encountered (memory). The pathways involved are complex and not completely elucidated. This brief review summarizes the information available currently regarding the multiple steps involved, with the aim of providing a general overview of the main aspects of photoimmunosuppression and its clinical consequences.