Endoscopic, image-guided, transnasal instillation of (32)P for recurrent infrachiasmatic cystic craniopharyngioma.

INTRODUCTION: The neurovascular and anatomic relationships surrounding craniopharyngiomas, and their tending to recur despite any method of primary treatment, has characterized this tumor as an exigent and frustrating clinical entity. Various strategies have been developed to deal with recurrences which include radical re-resection, stereotactic or localized radiotherapy, cyst fenestration, marsupialization or stent placement, and intracavitary therapies such as bleomycin or radionucleotides. CASE REPORT: We present a case where the patient had previously experienced a transsphenoidal resection followed by a pterional, microsurgical resection of her craniopharyngioma at an outside hospital. The second recurrence was cystic, and confined to the sella. We elected to proceed with a minimally invasive, transnasal endoscopic approach for the instillation of phosphorus 32 radionucleotide into the cyst. There were no complications, and the patient was discharged home on postoperative day one. At six months, there was no progression of the cyst. CONCLUSION: While intracystic adionucleotide therapies have been utilized for primary and secondary treatment of craniopharyngioma, to our knowledge, this is the first report of the delivery of this therapy by an endoscopic transsphenoidal route.

Sulfate as a synergistic anion facilitating iron binding by the bacterial transferrin FbpA: the origins and effects of anion promiscuity.

The ferric binding protein, FbpA, has been demonstrated to facilitate the transport of naked Fe3+ across the periplasmic space of several Gram-negative bacteria. The sequestration of iron by FbpA is facilitated by the presence of a synergistic anion, such as phosphate or sulfate. Here we report the sequestration of Fe3+ by FbpA in the presence of sulfate, at an assumed periplasmic pH of 6.5 to form FeFbpA-SO4 with K'(eff) = 1.7 x 10(16) M(-1) (at 20 degrees C, 50 mM MES, 200 mM KCl). The iron affinity of the FeFbpA-SO4 protein assembly is 2 orders of magnitude lower than when bound with phosphate and is the lowest of any of the FeFbpA-X assemblies yet reported. Iron reduction at the cytosolic membrane receptor may be an essential aspect of the periplasmic iron-transport process, and with an E(1/2) of -158 mV (NHE), FeFbpA-SO4 is the most easily reduced of all FeFbpA-X assemblies yet studied. The variation of FeFbpA-X assembly stability (K'(eff)) and ease of reduction (E(1/2)) with differing synergistic anions X(n-) are correlated over a range of 14 kJ, suggesting that the variations in redox potentials are due to stabilization of Fe3+ in FeFbpA-X by X(n-). Anion promiscuity of FbpA in the diverse composition of the periplasmic space is illustrated by the ex vivo exchange kinetics of FeFbpA-SO4 with phosphate and arsenate, where first-order kinetics with respect to FeFbpA-SO4 (k = 30 s(-1)) are observed at pH 6.5, independent of entering anion concentration and identity. Anion lability and influence on the iron affinity and reduction potential for FeFbpA-X support the hypothesis that synergistic anion exchange may be an important regulator in iron delivery to the cytosol. This structural and thermodynamic analysis of anion binding in FeFbpA-X provides additional insight into anion promiscuity and importance.

Complications of lumbar drainage after thoracoabdominal aortic aneurysm repair.

OBJECTIVES: Paraplegia remains a frequent complication of thoracoabdominal aortic aneurysm (TAAA) repair. Many adjunct therapies have been developed to address this complication. Lumbar drainage is frequently used in an attempt to decrease intrathecal pressure and improve intramedullary perfusion pressure. The effectiveness of this therapy is unclear, and the complications of lumbar drainage used for this indication are unknown. We present a case of intraspinal hematoma with significant neurologic deficit after TAAA repair and review the associated complications of lumbar drains placed for TAAA. METHODS: The charts of all patients undergoing operations for TAAA repair were reviewed. Patients who underwent perioperative placement of a lumbar drain were included regardless of aneurysm type or etiology. Demographics, Crawford grade, and perioperative parameters and complications were reviewed. RESULTS: Sixty-five patients underwent TAAA repair with 62 (95%) receiving a preoperative lumbar drain. There were two (3.2%) intraspinal hemorrhagic complications, including one patient with a poor neurologic outcome. No infections or other complications directly related to drainage were identified. Multivariate logistic regression analysis failed to demonstrate a significant association between lumbar drain complications and perioperative and intraoperative parameters such as blood loss or hypotension, level of drain placement, and Crawford grade. CONCLUSIONS: Lumbar drainage is a frequent adjunct to TAAA repair. However, placement of the drain itself can be associated with significant complications whose aggravating factors may be unidentifiable. Complications resulting from lumbar drainage should be considered in any patient who has postoperative lower extremity neurologic deficits.

Mechanical stability of polyethylene liners cemented into acetabular shells.

Revision of well-fixed, metal-backed acetabular components for dislocation or polyethylene failure requires consideration of removing the entire construct or replacing the polyethylene liner only. For non-modular or first-generation modular components with poor locking mechanisms, one option is to cement undersized liners into well-fixed shells. The purpose of this study was to measure the stability of undersized liners cemented into metal acetabular shells and compare the results with those of modular components. Hooded polyethylene liners measuring 28 x 50 mm and 28 x 56 mm were cemented into 66-mm acetabular shells (Smith & Nephew, Inc., Memphis, TN) with Simplex-P polymethylmethacrylate cement (Howmedica, Inc., Rutherford, NJ) giving 4- and 2-mm cement mantles, respectively. The force required to lever-out the liners from the shells was measured using the protocol described by Tradonsky et al. Assemblies with 4-mm mantles dissociated at an average of 322 +/- 47 in-lbf.; however, the assemblies with 2-mm mantles would not dissociate before the polyethylene yielded at torques as high as 600 in-lbf. These results compare favorably with the previously reported range (43 to 684 in-lbf) for modular acetabular components. These results suggest that undersized polyethylene liners can be cemented into well-fixed acetabular shells and expected to be stable.

Effect of leukocyte-endothelial adhesion antagonism on neutrophil migration and neurologic outcome after cortical trauma.

BACKGROUND: Administration of anti-CD11B, a monoclonal antibody directed against the leukocyte adhesion molecule CD11B, results in decreased neutrophil infiltration into injured tissue after experimental ischemia. We determined the effect of anti-CD11B administration on neutrophil migration and neurologic functioning after experimental cortical trauma. METHODS: Injuries were produced by a pneumatic impactor. Treatment animals received anti-CD11B after injury. Neurologic functioning was quantitated at 1, 12, and 24 hours after injury. Neutrophil migration was assessed with the myeloperoxidase assay. RESULTS: Neutrophil influx was increased in injured cortex after trauma. Anti-CD11B significantly reduced neutrophil influx. There was no significant improvement in neurologic functioning after MAb administration. CONCLUSIONS: These results show there is marked neutrophil response to injury as produced with the pneumatic contusion model. This migration may be significantly attenuated by administration of a anti-CD11B.

Histiocytic lesion mimicking intrinsic brainstem neoplasm. Case report.

This 10-year-old girl presented with a 1-month history of progressive bulbar palsy and a solitary enhancing mass originating within the floor of the fourth ventricle. Results of initial imaging studies and presentation were suggestive of neoplasia. Subtotal resection was performed and pathological examination revealed the mass to be a histiocytic lesion, with no evidence of a glioma. The patient had no other stigmata of histiocytosis and was treated with steroid medications, resulting in prolonged resolution of the lesion. This case demonstrates that for discrete brainstem lesions the differential diagnosis includes entities other than glioma for which treatment is available. Biopsy sampling should be considered when technically feasible.

Genetic screening and the right not to know.

This article discusses the basic elements of genetic screening and monitoring, the Americans With Disabilities Act of 1990, the constitutional issues, and the possibility of government mandated genetic monitoring or screening. The field of genetics offers the promise of unearthing the causes of a wide range of mysterious diseases and potentially finding their cures. Genetic screening and monitoring will play a large role in the application of these new findings. While these technologies offer great promise for the future of medicine, and the eradication of certain genetically linked diseases, until there are cures for persons with the faulty genes, such knowledge can lead to anxious preoccupation with the ever present disease potential within, and discrimination by employers, insurers, governmental agencies, and health care providers without. Given these unpleasant results of genetic screening or monitoring, it is important to assert the individual's right not to know.

Fatigue performance of ultra-high-molecular-weight polyethylene: effect of gamma radiation sterilization.

Ultra-high-molecular-weight polyethylene (UHMWPE) failure presents a significant materials concern in the orthopaedic community. Clinical failure following joint arthroplasty can result from the biological response to wear debris as well as structural failure owing to UHMWPE fatigue. In this study, cantilever rotating beam fatigue testing was conducted on GUR 415 UHMWPE in both the unsterilized and gamma radiation sterilized conditions. Calculations of flexural fatigue stresses were based on extreme fibre stresses and assumed negligible plastic deformation. Both material conditions exhibited similar fatigue strengths at 250,000 cycles (approximately 41 MPa) and at one million cycles (approximately 36 MPa), but a large difference developed after two million cycles. At ten million cycles, the unsterilized condition exhibited a fatigue strength of approximately 31 MPa, while the gamma-sterilized condition exhibited a reduced fatigue strength of approximately 18 MPa, an approximate decrease of 42%. High-cycle fatigue testing was necessary to fully characterize this behaviour owing to the pronounced difference in fatigue behaviour beyond two million cycles. These results suggest that gamma radiation sterilization of UHMWPE medical implants reduces their resistance to cyclic loading and, subsequently, may contribute to the associated fatigue-related failures which have been reported clinically.