Each year the field of orthopedics is introduced to an influx of new medical devices. Each of these medical devices has faced certain hurdles prior to being approved for marketing by the U.S. Food and Drug Administration (FDA). Among the regulatory pathways available, the 510(k) premarket notification is by far the one most commonly used. The 510(k) premarket notification allows the manufacturer to receive prompt approval of their device by demonstrating that it is "substantially equivalent" to an existing legally marketed device. In most instances, this proof of substantial equivalence allows manufacturers of medical devices to bypass the use of clinical trials, which are a hallmark of the approval process for new drugs. As a result, most medical devices are approved without demonstrating safety or effectiveness. This article reviews the regulatory processes used by the FDA to evaluate new orthopedic devices.
Bdellovibrio are small motile bacteria that attack and parasitize larger Gram-negative bacteria and since they might have practical applications, these organisms are attracting the attention of researchers as indicated by the sequencing of the B. bacteriovorus genome. There is an earlier report showing that B. bacteriovorus scavenges fatty acids from the host cell during its parasitic phase otherwise the biochemical nature of its lipids, particularly its complex lipids, remains unknown. We here report on the phospholipid classes of an axenically cultured host-independent strain (HID5). Phospholipids and fatty acids were identified by a variety of chromatographic procedures and high-resolution mass spectrometric techniques. Phosphatidylethanolamine was the major phospholipid and phosphatidylserine, cardiolipin, phosphatidylglycerol, and N-acylphosphatidylethanolamine were also identified. The major fatty acids were 16:0, 16:1, 18:1, and 9,10-Mt C16:0 (cyC17:0). Unlike another predatory bacterium, Bacteriovorus stolpii strain UKi2, sphingolipids were not detected in B. bacteriovorus by the procedures used in this study. This is consistent with the apparent lack of genes coding for sphingolipid biosynthesis enzymes in the B. bacteriovorus genome database. The results are consistent with the separation of Bdellovibrio and Bacteriovorus into separate genera.
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