DNA Repair Activity in the Skin of Day and Night Shift Workers

Study Overview
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Brief Summary
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The purpose of this study is to test how the skin of night shift workers responds to artificial sunlight (ultraviolet B radiation; UVB) at two different times of the day in comparison to normal day shift workers. After the skin biopsies are obtained, they will be brought to the laboratory to be exposed to UVB radiation and to measure UVB responses.

Official Title
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Pilot Study on DNA Repair Activity in the Skin of Day and Night Shift Workers

Conditions
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Skin Cancer

Intervention / Treatment
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* Radiation: Ultraviolet B Radiation
* Other: No Ultraviolet B Radiation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male/Female Fair skin (Fitzpatrick types I and II) Age 18 to 40 Able to comprehend procedures/risks Primarily work and are awake during normal daylight hours (6 am to 6 pm), or primarily work and are awake during night shifts hours (between the hours of 6 pm and 6 am) or may work a mixture of these shifts over the past 3 months. Rotating shifts will be categorized based on the majority of hours worked on average during the last 3 months. Able to fill out a 3-month calendar of work schedule. Exclusion Criteria: Known photosensitivity Currently on photosensitizing medications Diabetes Mellitus On any hormonal agents (e.g., birth control pills) History of abnormal scarring History of skin infections History of skin cancers History of sleep disorders such as sleep apnea or insomnia Known allergy to lidocaine local anesthetic Pregnancy or nursing Other serious health issues

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Day Shift Work Schedule<br>Day shift worker skin biopsies will be exposed to artificial sunlight (ultraviolet B radiation; UVB) at the laboratory. | Radiation: Ultraviolet B Radiation<br>* One skin punch biopsy will be taken to the laboratory for exposure to ultraviolet B radiation. After 1-hour incubation, the biopsies will be bisected in half.<br>Other: No Ultraviolet B Radiation<br>* One skin punch biopsy will be taken to the laboratory and will be kept as a non-irradiated control.<br>|
| Experimental: Night Shift Work Schedule<br>Night shift worker skin biopsies will be exposed to artificial sunlight (ultraviolet B radiation; UVB) at the laboratory. | Radiation: Ultraviolet B Radiation<br>* One skin punch biopsy will be taken to the laboratory for exposure to ultraviolet B radiation. After 1-hour incubation, the biopsies will be bisected in half.<br>Other: No Ultraviolet B Radiation<br>* One skin punch biopsy will be taken to the laboratory and will be kept as a non-irradiated control.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Expression level of the DNA repair factor XPA at two times of the day in the skin of day and night shift workers. | Reverse transcription quantitative PCR (RT-qPCR) and immunohistochemistry will be used to measure XPA expression at the mRNA and protein level, respectively, in skin samples obtained at 8 am and 4 pm. | After 1 hour incubation from ultraviolet B radiation exposure. | 
| Expression levels of core clock genes at two times of the day in the skin of day and night shift works. | Reverse Transcription Quantitative PCR (RT-qPCR) is used to measure the core circadian clock gene expression at the mRNA level in the skin samples obtained at 8 AM and 4 PM. | After 1 hour incubation from ultraviolet B radiation exposure. | 
| Activity of the nucleotide excision repair (NER) system at two times of the day in day and night shift workers. | A biochemical assay of nucleotide excision repair is used to measure NER in the skin samples obtained at 8 AM and 4 PM. | After 1 hour incubation from ultraviolet B radiation exposure. | 
| Activation of DNA damage kinase signaling pathways at two times of the day in the skin of day and night shift workers. | Immunohistochemistry is used to measure DNA damage kinase signaling (phosphorylated Chk1 and p53) in the skin samples obtained at 8 AM and 4 PM. | After 1 hour incubation from ultraviolet B radiation exposure. |