Anti-oxidation treatment of ultra high molecular weight polyethylene components to decrease periprosthetic osteolysis: evaluation of osteolytic and osteogenic properties of wear debris particles in a murine calvaria model.

Wear debris-induced osteolysis remains the greatest limitation of long-term success for total joint replacements with ultra-high molecular weight polyethylene (UHMWPE) bearings. To address oxidative degradation post-gamma irradiation, manufacturers are investigating the incorporation of antioxidants into PE resins. Similarly, larger molecular weight monomers have been developed to increase crosslinking and decrease wear debris, and ultimately osteolysis. However, the effects of modifying monomer size, crosslink density, and antioxidant incorporation on UHMWPE particle-induced osteoclastic bone resorption and coupled osteoblastic bone formation have never been tested. Here, we review the field of antioxidant-containing UHMWPE, and present an illustrative pilot study evaluating the osteolytic and osteogenic potential of wear debris generated from three chemically distinct particles (MARATHON®, XLK, and AOX™) as determined by a novel 3D micro-CT algorithm designed for the murine calvaria model. The results demonstrate an approach by which the potential osteoprotective effects of antioxidants in UHMWPE can be evaluated.

Human mitochondrial oxidative capacity is acutely impaired after burn trauma.

BACKGROUND: Mitochondrial proteins and genes are damaged after burn injury in animals and are assessed in human burn patients in this study. METHODS: The rates of maximal muscle mitochondrial oxidative capacity (adenosine triphosphate production) and uncoupled oxidation (heat production) for both palmitate and pyruvate were measured in muscle biopsies from 40 children sustaining burns on more than 40% of their body surface area and from 13 healthy children controls. RESULTS: Maximal mitochondrial oxidation of pyruvate and palmitate were reduced in burn patients compared with controls (4.0 +/- .2:1.9 +/- .1 micromol O2/citrate synthase activity/mg protein/min pyruvate; control:burn; P < .001 and 3.0 +/- .1: .9 +/- .03 micromol O2/citrate synthase activity/mg protein/min palmityl CoA; control:burn; P = .003). Uncoupled oxidation was the same between groups. CONCLUSIONS: The maximal coupled mitochondrial oxidative capacity is severely impaired after burn injury, although there are no alterations in the rate of uncoupled oxidative capacity. It may be that the ratio of these indicates that a larger portion of energy production in trauma patients is wasted through uncoupling, rather than used for healing.

Insulin sensitivity is related to fat oxidation and protein kinase C activity in children with acute burn injury.

Impaired fatty acid oxidation occurs with type 2 diabetes and is associated with accumulations of intracellular lipids, which may increase diacylglycerol (DAG), stimulate protein kinase C activity, and inactivate insulin signaling. Glucose and fat metabolism are altered in burn patients, but have never been related to intracellular lipids or insulin signaling. Thirty children sustaining >40% total body surface area burns were studied acutely with glucose and palmitate tracer infusions and a hyper-insulinemic euglycemic clamp. Muscle triglyceride, DAG, fatty acyl CoA, and insulin signaling were measured. Liver and muscle triglyceride levels were measured with magnetic resonance spectroscopy. Muscle samples from healthy children were controls for DAG concentrations. Insulin sensitivity was reduced and correlated with whole body palmitate beta-oxidation (P = .004). Muscle insulin signaling was not stimulated by hyper-insulinemia. Tissue triglyceride concentrations and activated protein kinase C-beta were elevated, whereas the concentration of DAG was similar to the controls. Free fatty acid profiles of muscle triglyceride did not match DAG. Insulin resistance following burn injury is accompanied by decreased insulin signaling and increased protein kinase C-beta activation. The best metabolic predictor of insulin resistance in burned patients was palmitate oxidation.

Ductal prostate cancer: contemporary management and outcomes.

OBJECTIVES: To evaluate contemporary management and outcomes of ductal prostate cancer (PCA). MATERIALS AND METHODS: We reviewed all patients with ductal PCA and at least 6 months of follow-up seen at UTMB from 1990 to 2005, which comprised 17 patients (mean age: 67.7 years, range 55-87). At time of diagnosis, 11 patients had localized disease (Group 1) and 6 patients had distant metastasis (Group 2). RESULTS: Treatment of Group 1 patients included radiation and endocrine treatment for at least 2 years (n = 7), radiation alone (n = 2), and radical surgery (n = 2). At a mean follow-up of 3.6 years (r = 1-12 years) 8 patients (67.7%) remained free of recurrence, 1 patient had biochemical recurrence alone, 1 patient had recurrence in the anterior urethra, and the other had progression with metastasis to the brain and subsequent death. In addition to metastasis to regional/distant lymph nodes and bone in Group 2, metastatic sites included brain (n = 1), peritoneum (n = 1), and lung (n = 1). Mean follow-up was 2.3 years (r = 8 months to 4 years). All patients received androgen deprivation. One patient had progression of disease despite lack of biochemical recurrence and is alive at 2.5 years. One patient died from other causes while the 4 remaining patients are in remission at last follow-up. CONCLUSIONS: Contemporary management of localized ductal PCA with radiation and endocrine therapy yields adequate disease-free survival. Metastatic sites include brain, lung, peritoneum, and anterior urethra, and most patients respond well to endocrine treatment.

Retroperitoneal mucinous cystadenocarcinoma in a man: case report and review of the literature.

In the English medical literature, 27 cases of primary retroperitoneal mucinous cystadenocarcinoma have been published. We report the second case of a primary retroperitoneal mucinous cystadenocarcinoma in a man. The patient was an 83-year-old man, with a large 26 x 20 x 16-cm retroperitoneal cystic mass causing abdominal discomfort and cachexia, who underwent excision of the mass. Prior reports suggest that this type of tumor has an aggressive clinical course, and surgical excision is the treatment of choice. These rare tumors need to be included in the differential of retroperitoneal cystic tumors.

Isolated recurrence of ductal prostate cancer to anterior urethra.

We report the case of a 74-year-old man with ductal prostate cancer who had originally undergone radiotherapy but developed metastases to the anterior urethral mucosa. This is the fourth such case ever reported in English publications. We suspect the metastases developed from implantation after instrumentation, a common finding in the previously reported cases. Although no specific treatment regimen exists, we believe that local resection followed by androgen deprivation is the treatment of choice in these patients.

Renal and perirenal abscesses in patients with otherwise anatomically normal urinary tracts.

PURPOSE: We characterized evaluation, management and outcomes in a group of patients diagnosed with renal and perirenal abscesses who had otherwise anatomically normal urinary tracts. MATERIALS AND METHODS: We reviewed our experience with renal/perirenal abscesses at University of Texas Medical Branch from 1991 to 2002. Treatment was determined by physician preference in each individual. RESULTS: Of 70 patients with renal/perirenal abscesses 26 had otherwise anatomically normal urinary tracts, 24 (92%) had at least 1 possible contributory factor, such as diabetes mellitus, and only 38% had the correct diagnosis at initial presentation. The abscess was intranephric in 39% of cases, intranephric and perinephric in 19%, and perinephric only in 42%. Of the 26 patients 18 were treated with percutaneous drainage or aspiration of the abscess and 12 (66.7%) had positive cultures. Eight of the 12 patients (67%) with positive abscess cultures had the same organism in urine and/or blood. All 26 patients were treated with broad-spectrum intravenous antibiotics. In most patients abscess size influenced additional treatments, such as percutaneous needle aspiration or catheter drainage. None of the patients required open surgical drainage, nephrectomy or nephrostomy tube placement. At a mean followup of 10 months all patients had complete radiographic resolution of the abscess without further complications except 1 who had pyelonephritis and another who was found to have a poorly perfused kidney. CONCLUSIONS: With accurate diagnosis and minimally invasive therapy patients with renal and/or perirenal abscesses and otherwise anatomically normal urinary tracts have excellent functional and anatomical outcomes.

Testicular involvement in disseminated fungal infection by Pseudallescheria boydii.

We present an immunocompromised patient with a painless testicular mass. Usually, this mass is suspicious for testicular cancer; however, a fungal abscess from Pseudallescheria boydii was found. The patient eventually died from disseminating infection. This is the first such report of a testicular infection involving P. boydii. Early diagnosis and treatment are paramount because of the poor outcome with disseminated disease.