Retinal Vascular Occlusion after COVID-19 Vaccination: More Coincidence than Causal Relationship? Data from a Retrospective Multicentre Study.

Background: To investigate whether vaccination against SARS-CoV-2 is associated with the onset of retinal vascular occlusive disease (RVOD).

Methods: In this multicentre study, data from patients with central and branch retinal vein occlusion (CRVO and BRVO), central and branch retinal artery occlusion (CRAO and BRAO), and anterior ischaemic optic neuropathy (AION) were retrospectively collected during a 2-month index period (1 June-31 July 2021) according to a defined protocol. The relation to any previous vaccination was documented for the consecutive case series.

Biochemical markers of bone turnover for the clinical assessment of bone metabolism.

Despite these potential problems, biochemical bone markers are the single most sensitive method for monitoring acute changes in bone metabolism. For example, subcutaneous injections of recombinant human insulin-like growth factor I cause a measurable increase in both procollagen and urinary DPD in as little as 1 day. Similarly, it is possible to measure a significant decrease in bone formation as determined by decreases in serum levels of ALP, OC, and C-PCP within 12 hours after the beginning of a PTH infusion study.

Changes in markers of bone formation and resorption in a bed rest model of weightlessness.

To study the mechanism of bone loss in physical unloading, we examined indices of bone formation and bone resorption in the serum and urine of eight healthy men during a 7 day -6 degrees head-down tilt bed rest. Prompt increases in markers of resorption--pyridinoline (PD), deoxypyridinoline (DPD), and hydroxyproline (Hyp)/g creatinine--during the first few days of inactivity were paralleled by tartrate-resistant acid phosphatase (TRAP) with significant increases in all these markers by day 4 of bed rest. An index of formation, skeletal alkaline phosphatase (SALP), did not change during bed rest and showed a moderate 15% increase 1 week after reambulation.