RESUMO
As the use of glenoid suture anchors in arthroscopic and open reconstruction, for instability after Bankart lesions of the shoulder, increases, an emerging problem has been the incidence of glenoid rim fractures through suture drill holes. Very little is known regarding the effect of the Hill-Sachs lesion on the glenoid's susceptibility to fracture and how drill hole location can further affect this. This study used finite element modeling techniques to investigate the risk of fracture of the glenoid rim in relation to variable sized Hill-Sachs defects impacting on the anterior glenoid edge with suture anchor holes placed in varying positions. The distribution of Von Mises (VM) stresses and the factor of safety (FOS) for each of the configurations were calculated. The greatest peak in VM stresses was generated when the glenoid was loaded with a small Hill-Sachs lesion. The VM stresses were lessened and the FOS increased (reducing likelihood of failure) with increasing size of the Hill-Sachs lesion. Placement of the suture drill holes at 2 mm from the glenoid rim showed the highest risk of failure; and when combined with a medium sized Hill-Sachs lesion, which matched the central line of the drill holes, a potentially clinically significant configuration was presented. The results of this study are useful in assisting the surgeon in understanding the interaction between the Hill-Sachs lesion size and the placement of suture anchors with the purpose of minimizing the risk of subsequent rim fracture with new injury.
RESUMO
The primary objective of this review is to propose an approach for the biosynthesis of phylloquinone (vitamin K1) based upon its known sources, its role in photosynthesis and its biosynthetic pathway. The chemistry, health benefits, market, and industrial production of vitamin K are also summarized. Vitamin K compounds (K vitamers) are required for the normal function of at least 15 proteins involved in diverse physiological processes such as coagulation, tissue mineralization, inflammation, and neuroprotection. Vitamin K is essential for the prevention of Vitamin K Deficiency Bleeding (VKDB), especially in neonates. Increased vitamin K intake may also reduce the severity and/or risk of bone fracture, arterial calcification, inflammatory diseases, and cognitive decline. Consumers are increasingly favoring natural food and therapeutic products. However, the bulk of vitamin K products employed for both human and animal use are chemically synthesized. Biosynthesis of the menaquinones (vitamin K2) has been extensively researched. However, published research on the biotechnological production of phylloquinone is restricted to a handful of available articles and patents. We have found that microalgae are more suitable than plant cell cultures for the biosynthesis of phylloquinone. Many algae are richer in vitamin K1 than terrestrial plants, and algal cells are easier to manipulate. Vitamin K1 can be efficiently recovered from the biomass using supercritical carbon dioxide extraction.
