New clothes for the jasmonic acid receptor COI1: delayed abscission, meristem arrest and apical dominance.

In a screen for delayed floral organ abscission in Arabidopsis, we have identified a novel mutant of CORONATINE INSENSITIVE 1 (COI1), the F-box protein that has been shown to be the jasmonic acid (JA) co-receptor. While JA has been shown to have an important role in senescence, root development, pollen dehiscence and defense responses, there has been little focus on its critical role in floral organ abscission. Abscission, or the detachment of organs from the main body of a plant, is an essential process during plant development and a unique type of cell separation regulated by endogenous and exogenous signals. Previous studies have indicated that auxin and ethylene are major plant hormones regulating abscission; and here we show that regulation of floral organ abscission is also controlled by jasmonic acid in Arabidopsis thaliana. Our characterization of coi1-1 and a novel allele (coi1-37) has also revealed an essential role in apical dominance and floral meristem arrest. In this study we provide genetic evidence indicating that delayed abscission 4 (dab4-1) is allelic to coi1-1 and that meristem arrest and apical dominance appear to be evolutionarily divergent functions for COI1 that are governed in an ecotype-dependent manner. Further characterizations of ethylene and JA responses of dab4-1/coi1-37 also provide new information suggesting separate pathways for ethylene and JA that control both floral organ abscission and hypocotyl growth in young seedlings. Our study opens the door revealing new roles for JA and its interaction with other hormones during plant development.

Multiple myeloma: diagnosis and orthopaedic implications.

Multiple myeloma is a hematologic malignancy that commonly affects the skeletal system. The disease is primarily managed medically with chemotherapeutic agents. Pathologic fractures are common in patients with diagnosed and undiagnosed disease. The number of patients diagnosed with multiple myeloma is increasing, as is the incidence of associated pathologic fractures. Novel chemotherapeutic agents and radiation therapy protocols have been used to extend the average life span of patients with this disease. Various methods that allow for restoration of function and pain reduction can be used to stabilize and manage fractures associated with multiple myeloma. The orthopaedic surgeon and oncology team must work together to develop an individualized treatment plan to improve patient quality of life and provide pain relief.

Femoral malrotation following intramedullary nail fixation.

Intramedullary nailing of femoral shaft fracture can result in inadvertent malalignment. Malrotation is the most common cause of deformity, but it is underrecognized, in part because of the difficulty in accurately assessing rotation as well as the variation that exists in normal anatomy. The consequences of femoral malrotation are not completely understood. However, initial biomechanical studies suggest that it causes a substantial change in load bearing in the affected extremity. Clinical examination, fluoroscopy, and ultrasonography are useful in measuring femoral rotational alignment intraoperatively and postoperatively. CT is useful in the identification of the degree of malrotation and in surgical planning.

Pedicle screw-based posterior dynamic stabilization in the lumbar spine.

Traditionally, management of spinal pathology has centered on decompression, correction of deformity, and stabilization. Deformity correction and stabilization have been accomplished largely by spinal fusion at the pathologic levels. In addition to the risks and potential complications, there are sequelae to a successful fusion. Therefore, attention is being directed toward disk replacement in the lumbar spine. In addition to their preserving motion in the anterior column, several posterior motion-preservation devices have been developed in an effort to prevent pathologic motion at both a decompressed level and a segment adjacent to a fusion. Initial studies suggest that the results of posterior dynamic stabilization may be comparable to those of fusion; however, longer periods of clinical and radiographic follow-up are required to fully define the role these devices may play in the management of the degenerative lumbar spine.

Combined heart-kidney transplantation: the University of Wisconsin experience.

BACKGROUND: Combined heart-kidney transplantation (HKTx) is increasing in frequency, but long-term outcomes are unknown and appropriately comparative analysis is lacking. METHODS: This study was a retrospective review of prospectively collected data for 19 HKTx patients. Patient and graft survival, graft rejection and coronary allograft vasculopathy (CAV) were compared for HKTx vs recipients of a heart (n = 515) or kidney alone (n = 3,188) or both organs at separate time-points (n = 8). RESULTS: Patient and graft survival did not differ for HKTx vs any group. HKTx time to first rejection episode was significantly prolonged for both organs vs single-organ recipients. The incidence of CAV was significantly lower for HKTx. CONCLUSIONS: HKTx provides outcomes similar to those for solitary heart or kidney transplantation. There may be an immunologic advantage to receiving organs in a combined fashion. Such allocation of organs seems medically appropriate; however, more refined strategies are needed to identify optimal recipient populations.

Early institution of extracorporeal membrane oxygenation for primary graft dysfunction after lung transplantation improves outcome.

BACKGROUND: Primary graft dysfunction (PGD) after lung transplantation (LTx) carries a significant mortality and clinical management is controversial. Extracorporeal membrane oxygenation (ECMO) has been used infrequently for recovery from acute lung injury (ALI) in this setting. We reviewed our experience with ECMO after primary LTx. METHODS: The present study is a retrospective analysis of all LTx patients between 1991 and 2004. Twenty-two patients sustained severe PGD with subsequent placement on ECMO. We analyzed indications and 30-day, 1-year and 3-year mortality. Complications and incidence of multiple-organ failure (MOF) were determined. Critical appraisal of the evidence available to date was performed. RESULTS: A total of 297 LTxs were performed during the study period, with 97.5%, 88.6% and 73.8% survival at 30 days, 1 year and 3 years, respectively. Twenty-two patients (7.9%) had severe allograft dysfunction leading to ECMO support. Twelve patients received single-lung (SLTx), 8 double-lung (BLTx), 1 single-lung/kidney (SLKTx) and 1 heart/lung (HLTx) transplantation. Thirty-day, 1-year and 3-year survival of LTx recipients with ECMO support post-operatively were 74.6%, 54% and 36%, respectively. MOF was the predominant cause of death (58.3%) in patients on ECMO support for PGD. CONCLUSIONS: Our data suggest that, in addition to prolonged ventilation and pharmacologic support, ECMO should be considered as a bridge to recovery from PGD in lung transplantation. Early institution of ECMO may lead to diminished mortality in the setting of ALI despite the high incidence of MOF. Late institution of ECMO was associated with 100% mortality in this investigation.

Is extreme obesity a risk factor for cardiac surgery? An analysis of patients with a BMI > or = 40.

BACKGROUND: The increasing prevalence of obesity is a public health concern and perceived as a potential risk factor in open heart surgery. We critically appraised the literature available regarding postoperative complications in obese patients. METHODS: A single-center retrospective evaluation of complication rates (1999-2004) in cardiac surgical patients categorized by body mass index (BMI) was conducted. The overall incidence of complications (CX), renal failure (RF), hemodialysis (HD), atrial fibrillation (AF), cardiac arrest (CA), infections (INF), stroke (CVA and TIA), prolonged ventilation (VENT), and pulmonary embolism (PE) were observed. Patients with normal BMI (20-30) served for comparison, obesity and extreme obesity (ExtOb) were defined as BMI 30-40 and > or =40, respectively. RESULTS: In our institutional review of 1920 patients, 1780 met the inclusion criteria with BMI<20 (n=53), 20-30 (n=1056), 30-40 (n=592), and > or =40 (n=79) based on National Health and Nutrition Examination Survey (NHANES) criteria. Significant increase in complications (STS database guideline definitions) were observed with a BMI> or =40, 58% versus 47% (p=0.04). Extremely obese patients (ExtOb) had increased length of stay (LOS) (11.4 days vs 9.6 days; p< or =0.01), rate of renal failure (14.3% vs 5%; p< or =0.01) and prolonged ventilation (39%; p=0.01) compared to non-obese patients. Extremely obese had no significant increase in hemodialysis (7.3% vs 3.2%; p=0.11) or stroke (5.2% vs 2.9%; p=0.29). Obese patients (Ob) had increased LOS (10 days vs 9.6 days; p=0.04) and prolonged ventilation (28.3% vs 23.5%; p=0.03). CONCLUSIONS: Cardiac surgery can be performed without significant increase in perioperative and 30-day mortality in obese and extremely obese patients. Overall complication rates and LOS in patients with BMI> or =40 is increased and demands attention. We provide evidence that rates of few specific complications increase with extreme obesity. For risk stratification in the setting of an obesity epidemic, we advocate an interdisciplinary approach in obese patients undergoing elective cardiac surgery.