T-BIRD: Tissue Biomechanics and Inflammation in the Rheumatic Diseases

Assessments of the elasticity / stiffness of the joints, skin and arteries. 1. Participants will answer a simple 5-point questionnaire asking questions about the mobility of their joints. 2. An assessor will painlessly assess the range of motion of the joints of the finger joints, wrists, elbows, knees and spine. 3. The flexibility of the right 5th finger will be formally tested in a device that stretches the finger backwards using specific forces (torques). 4. The skin elasticity will be evaluated first by drawing two dots 10 mm apart on th dorm of the right hand and measuring how far they can be stretched apart by the examiner. 5. The skin elasticity of the solar aspect of the right forearm will be measured as the volume of skin/tissue that can be drawn into the barrel of a 50mL syringe (plunger removed) in response to specific negative pressures. 6. The thickness of the skin will be measured at both sites using a pair of Harpenden skin fold callipers. 7. Arterial stiffest will be firstly measured as carotid-femoral pulse wave velocity (the delay between the the carotid and femoral pulses measured using a pressure transducer applied to the carotid and an inflatable cuff around the thigh. Carotid-Femoral Pulse Wave Velocity will be repeated on a second occasion 1 day - 4 weeks of the first assessment. Then endothelial fiction, the ability to dilate, will be measured as the strength of the pulses in the finger tips after a 5 minute period of complete occlusion of blood flow to the left arm using an inflatable cuff. Assessment of the severity of arthritis (in the rheumatoid arthritis and psoriatic arthritis groups) 1. Severity of arthritis will be evaluated as the number of tender and swollen joints, blood tests for inflammation (ESR, CRP) (to determine how well arthritis is controlled) and 2. The strength of treatment required to achieve this control (what drugs the participant is receiving). These assessments will be conducted over two visits. The majority of the assessments can be completed on the first visit. Upon the second visit carotid-femora pulse wave velocity will be measured a second time and any assessments not already conducted on the first occasion will be completed on the second occasion.