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Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular disease characterized by the formation of cutaneous and visceral telangiectasias and arteriovenous malformations (AVM). Multiple organs may be affected, including the nasal mucosa, skin, lungs, gastrointestinal tract, and brain. The following case highlights a unique manifestation of HHT in a patient with a gastrointestinal hemorrhage and epistaxis, resulting in hyperammonemia and diffuse cerebral edema and herniation. Clinicians should be aware of this potential complication in such patients and initiate ammonia-reducing agents early to avoid this devastating consequence.
RESUMO
BACKGROUND: Clinicians are often faced with the decision whether to revise a painful total knee replacement in patients who have chronic vague pain with no apparent explanation. A sensitive metal testing assay called the lymphocyte stimulation test has been used to detect nickel sensitization in patients with orthopedic implants. We hypothesize that nickel sensitization plays a role in the pathology of failed joint arthroplasty in patients with unexplained dissatisfaction. METHODS: 32 patients with symptomatic total knee arthroplasty without obvious mechanical findings were tested prior to revision surgery. 19 nickel-sensitized and 13 non-sensitized patients were compared by cell counts of synovium surgical specimens for CD4+ and CD8+ cell lines. Patients were then revised with ceramic-coated implants. Secondary evaluation of functional outcomes, range of motion, and pain relief were assessed. RESULTS: Nickel-sensitive patients showed a statistical increase in CD4+ reactivity compared to CD8+ reactivity. The ratio of CD4+/CD8+ T lymphocytes was 1.28 in nickel-sensitive patients versus 0.76 in the control (p = 0.009). There was no difference in functional scores, clinical scores, or range of motion after revision. CONCLUSIONS: This study provides objective data via histological analysis in support of a nickel allergic sensitization in failed arthroplasties where clinical and/or radiographic abnormalities may not be apparent. Biopsy for CD4+/CD8+ cell counts may provide further proof of the existence of nickel sensitization in lymphocyte stimulation test positive patients, and more importantly, may implore the surgeon to consider low nickel implant design in these patients.
RESUMO
The ability of cells to sense and respond to endogenous electric fields is important in processes such as wound healing, development, and nerve regeneration. In cell culture, many epithelial and endothelial cell types respond to an electric field of magnitude similar to endogenous electric fields by moving preferentially either parallel or antiparallel to the field vector, a process known as galvanotaxis. Here we report on the influence of dc electric field and confinement on the motility of fibroblast cells using a chip-based platform. From analysis of cell paths we show that the influence of electric field on motility is much more complex than simply imposing a directional bias towards the cathode or anode. The cell velocity, directedness, as well as the parallel and perpendicular components of the segments along the cell path are dependent on the magnitude of the electric field. Forces in the directions perpendicular and parallel to the electric field are in competition with one another in a voltage-dependent manner, which ultimately govern the trajectories of the cells in the presence of an electric field. To further investigate the effects of cell reorientation in the presence of a field, cells are confined within microchannels to physically prohibit the alignment seen in 2D environment. Interestingly, we found that confinement results in an increase in cell velocity both in the absence and presence of an electric field compared to migration in 2D.