Lead fragmentation

Up until this point we have described how molecules may be selected to be similar or diverse and how they may be filtered and scored as to how like categories of molecule (drug, lead, fragment, natural product) they are. The following sections will describe how these methods are applied to the design of individual arrays and entire screening collections. 

Class I 1. Lead removal is recommended in patients with clinically significant thromboembolic events associated with thrombus on a lead or a lead fragment C... 

Life-threatening arrhythmias secondary to retained leads or lead fragments ... 

Lickfett L, Wolpert C, Jung W et al (1999) Inappropriate implantable defibrillator discharge caused by a retained pacemaker lead fragment. J Interv Card Electrophysiol 3 163-167... 

Traction devices specialized locking stylets, snares, sutures, grasping, or other devices used to engage or entrap and remove the lead or lead fragments. 

The transfemoral approach is adopted in many centers as a primary approach when free-floating leads are involved and as an alternative approach in case of failed primary approach through the implant vein [23, 43-45]. Some techniques using the transfemoral approach allow grasping and removal of exposed or intravascular leads, fragments of... 

High quality fluoroscopy a high-quality fluoroscopy system is a mainstay for lead extraction. Visualization of small lead components (such as stretched conductor coils, screws and embolized lead fragments) is fundamental to the safe performance of lead extraction. The equipment may be a fixed fluoroscopic system or a mobile high quality C-arm. Personnel specifically able to operate and troubleshoot this equipment are also required. 

The intravascular position of the leads or lead fragments is relatively common in patients undergoing transvenous lead extraction. Lead to remove can be free floating either as (1) the result of lead fracture in its intravascular course or (2) the result of an intervention. 

A unique index number is assigned to each biosteric transformation record. The first three letters of the ID code specify the chemical type of the starting lead fragment while the subsequent three to four numbers are sequence indicators. The first part of the ID code can be used for a quick search for replacements for a common coded functionality, such as QUI, which stands for quinazoline in the example shown in Figure 4.3. The ID codes in the current version of the database are cataloged in Table 4.1. 

The lead can be cut and the incision closed then the infected area can be opened, the clean distal portion of the lead pulled into the infected area, and that portion removed. This allows a total separation of the retained lead fragment from the infected area. 

Minnesota Dept, of Natural Resources [www.dnr.state.mn.us] X-rays from a study by Lou Cornicelli, DNR big game program coordinator, showed that lead fragments travel inside a body far beyond the bullet s primary wound channel. It never dawned on me that it might be an issue, said Cornicelli. Copper bullets leave no lead. ... 

The truth is, writes the Peregrine Fund, that Dr. Cornatzer s study was motivated by a presentation by Peregrine Fund staff to the Board in May 2007 showing that lead fragments in the remains of hunter-killed animals are respon-... 

ND departments of Health, Agriculture and Game and Fish advise food pan-tries not to distrihute or use donated ground venison because of contamination with lead fragments. It is no different, they note, from the precautions they would take when any food, heef to spinach, is contaminated. ... 

Andrea Grondahl, DVM, State Meat and Poultry Inspection Director, ND Dept, of Agriculture, writes to venison processors. Recent studies in ND and other Mid-western states, she says, found lead fragments in venison. There is currently no evidence linking venison consumption to lead poisoning in humans. ... 

ND develops guidance for hunters and processors regarding cleaning and dressing wild game to reduce the chances of lead fragments in game harvested with lead bullets. ... 

A Miimesota Dept, of Natural Resources study (see above) indicates that lead particles commonly are found farther from a wound channel than previously thought that the number of lead fragments varies widely by bullet type and that most lead particles in venison are too small to see, feel or sense when chewing. 

---