A1 Adenosine Receptor-Mediated Inhibition of Parasympathetic Neuromuscular Transmission in Human and Murine Urinary Bladder.

The potential role of A1 adenosine receptors in modulating neuromuscular transmission in the detrusor muscle of the urinary bladder has been tested in human and murine preparations with the intent to determine the viability of using adenosine receptor agonists as adjuncts to treat overactive bladder. In human detrusor muscle preparations, contractile responses to electrical field stimulation were inhibited by the selective A1 adenosine receptor agonists 2-chloro-N(6)-cyclopentyladenosine, N(6)-cyclopentyladenosine (CPA), and adenosine (rank order of potency: 2-chloro-N(6)-cyclopentyladenosine > CPA > adenosine). Pretreatment with 8-cyclopentyl-3-[3-[[4(fluorosulphonyl)benzoyl]oxy]propyl]-1-propylxanthine, an irreversible A1 antagonist, blocked the effects of CPA, thus confirming the role of A1 receptors in human detrusor preparations. In murine detrusor muscle preparations, contractions evoked by electrical field stimulation were reduced by CPA or adenosine. Amplitudes of the P2X purinoceptor-mediated excitatory junctional potentials (EJPs) recorded with intracellular microelectrodes were reduced in amplitude by CPA and adenosine with no effect on the spontaneous EJP amplitudes, confirming the prejunctional action of these agents. 8-Cyclopentyltheophylline, a selective A1 receptor antagonist, reversed the effects of CPA on EJP amplitudes with no effect of spontaneous EJPs, confirming the role of A1 receptors in mediating these effects.

Curative treatment without surgical reconstruction after perineal debridement of Fournier's gangrene.

BACKGROUND: Fournier's gangrene (necrotizing fasciitis) is an acute life-threatening disease of the perineal area that requires urgent medical intervention. Once the affected area is surgically debrided and the patient is stabilized, surgical management typically involves 1 or more additional procedures that may include split-thickness skin grafts, flaps, or an elective diverting urostomy and/or colostomy. The professional literature discussing nonsurgical approaches to healing for Fournier's gangrene after surgical debridement is sparse. CASE: We present 3 cases of male patients with Fournier's gangrene from our facility who healed uneventfully with negative pressure wound therapy placed after extensive debridement without further surgical intervention. An added benefit was a satisfactory aesthetic effect. CONCLUSION: Expert wound management including negative pressure wound therapy after surgical debridement of Fournier's gangrene eliminated the need for further operative procedures and prolonged hospitalizations in these cases. We believe that surgical teams should consider using negative pressure wound therapy as part of the initial curative plan of care after debridement, and that plans for restorative plastic surgery should be restricted to patients who do not exhibit adequate improvement with conservative wound management.

Capromab pendetide scanning has a potential role in optimizing patient selection for salvage cryosurgical ablation of the prostate.

OBJECTIVES: To evaluate an algorithm using Capromab pendetide scanning (CPS) and prostate biopsy to select appropriate patients with biochemical recurrence (BCR) after radiation therapy (RT) for salvage cryosurgical ablation of the prostate (CSAP) and to avoid premature androgen deprivation therapy (ADT); and to estimate the local salvage success rate for patients with high-risk clinical features. METHODS: Sixty-nine patients underwent a history, physical, CPS, and prostate biopsy. Patients with a negative or prostate-only positive signal and a positive biopsy were offered CSAP. Success was defined as a postsalvage nadir PSA of ≤ 0.4 ng/mL. Patients who failed were followed to establish when they required ADT. The results were compared with the putative results of applying clinical parameters alone. Patients were considered high-risk if they had any of the following characteristics: stage T3B-T4, Gleason ≥ 4 + 3, PSADT ≤ 10 months or presalvage PSA > 10 ng/mL. RESULTS: Twelve patients (6 with metastatic signal and 6 with negative biopsy) were excluded. Fifty-seven patients underwent CSAP. Overall 67% were successfully treated. Pre-salvage PSA was significantly associated with success (P = .013). Using clinical risk alone, only 14 patients achieved success compared with 38 using our algorithm. Most of the patients (75%) avoided ADT over a period of 21 months. CONCLUSIONS: Using our algorithm with CPS and prostate biopsy enabled us to spare some low-risk patients the undue morbidity of local salvage procedures that are likely to fail, while offering selected high-risk patients the opportunity for cure, avoiding premature ADT. Low presalvage PSA seems to be correlated with successful outcomes.

Acid ceramidase inhibition: a novel target for cancer therapy.

During the last decade, sphingolipid deregulation, namely the balance between the pro-apoptotic molecule ceramide and the anti-apoptotic sphingolipid sphingosine-1-phosphate, has emerged as an important factor in cancer pathology and resistance to therapy. Thus, our research has been focused on developing drugs that are able to restore normal sphingolipid balance, precisely through increasing the levels of ceramide and decreasing sphingosine-1-phosphate. Particularly, inhibition of the ceramide metabolizing enzyme acid ceramidase, whose over-expression in cancer cells has been implicated in resistance to treatment, is proving to be an efficient and promising strategy. In this review, we consider our recent work with acid ceramidase inhibitors, in combination with radiation or gene therapy as a sensitizer that enhance cancer therapy.

Role of acid ceramidase in resistance to FasL: therapeutic approaches based on acid ceramidase inhibitors and FasL gene therapy.

Head and neck squamous cell cancers (HNSCC) are particularly aggressive and are resistant to many forms of treatment. Ceramide metabolism has been shown to play an important role in cancer progression and cancer resistance to therapy in many tumor models, including HNSCC. Here, we study the role of the ceramide-metabolizing enzyme acid ceramidase (AC) in therapeutic responses in HNSCC. First, we show that AC is over-expressed in 70% of head and neck squamous cell tumors compared with normal tissues, suggesting that this enzyme may play an important role in facilitating HNSCC growth. Next, comparison of three HNSCC cell lines with low, medium, and high levels of AC reveals an inverse correlation between the levels of AC and their response to exogenous C-6-ceramide. Furthermore, over-expression of AC in SCC-1 cells increased resistance to Fas-induced cell killing. Conversely, down-regulation of AC using specific AC small interfering RNA (siRNA) sensitized the SCC-1 cancer cell line to Fas-induced apoptosis. Finally, we show that the AC inhibitor LCL 204 can sensitize HNSCC cell lines to Fas-induced apoptosis both in vitro and in a xenograft model in vivo, suggesting that the combination of FasL gene therapy and LCL 204 may become a new treatment option for advanced-stage head and neck cancer.

Salvage cryosurgical ablation of the prostate for local recurrence after radiation therapy: improved outcomes utilizing a capromab pendetide scan and biopsy algorithm.

PURPOSE: We assessed the efficacy, complications and technical advancements in salvage cryosurgical ablation of the prostate for recurrent prostate cancer after radiation therapy. METHODS: A total of 58 patients were evaluated for salvage cryosurgery using an algorithm of capromab pendetide scan and prostate biopsy from January 2003-July 2007. Forty-seven patients underwent salvage cryosurgery and biochemical recurrence free survival and complications were retrospectively reviewed. Mean follow-up was 24 months. RESULTS: Seventy percent of patients achieved a nadir PSA < 0.5 ng/ml. Overall, 51% of patients achieved a durable PSA response with a pre-salvage serum PSA < 10 predictive of success. There were no major complications and minor complications were few. CONCLUSION: Salvage cryotherapy in experienced hands utilizing third-generation technology provides for excellent biochemical control with minimal morbidity.

Involvement of sphingolipids in apoptin-induced cell killing.

The potential anti-tumor agent Apoptin activates apoptosis in many human cancers and transformed cell lines, but is believed to be less potent in primary cells. Although caspase 3 is activated during apoptin-induced apoptosis, the mechanism of tumor cell killing remains elusive. We now show that apoptin-mediated cell death involves modulation of the sphingomyelin-ceramide pathway. Treating cells with Ad-GFPApoptin resulted in increased ceramide accumulation and enhanced expression of acid sphingomyelinase (ASMase) with a concomitant increase in ASMase activity and decreased sphingomyelin. Using confocal microscopy, ASMase, normally present in the endosomal/lysosomal compartment, was observed to translocate to the cell's periphery. Cotreatment of Ad-GFPApoptin-infected cells with the ASMase inhibitor desipramine (2.5 muM) attenuated (30%; P<0.01) apoptin-induced cell death. Apoptin was also able to induce a significant decline in sphingosine content by inhibition of ceramide deacylation through down-regulation of acid ceramidase at the protein level. Supporting the role of ceramide in apoptin action, treatment of cells with the combination of an exogenous cell-permeable ceramide analog (C6-ceramide) and Ad-GFPApoptin infection yielded a significant increase (P<0.01) in apoptosis over either treatment modality alone. Together, these data suggest that apoptin modulates ceramide/sphingolipid metabolism as part of its mechanism of action.