Aspirin blocks binding of photosensitizer SnET2 into human serum albumin: implications for photodynamic therapy.

Tin etiopurpurin dichloride (SnET2) is one of the photosensitizers under investigation to be used in photodynamic therapy of prostate cancer. The drug is delivered intravenously, transported in vivo by liposomes and plasma proteins and localized within the prostate. SnET2 exists in two tautomeric forms (I - closed ring, II - open ring) with I converting spontaneously into the more energetically stable form II at physiological pH. Up to approximately 50% of the drug can be carried by serum albumin, although this association can increase photo-bleaching and diminish the drug efficiency. Molecular modeling and force field calculations indicate that Sudlow Site I in human serum albumin (HSA) is the most probable binding site for both forms of SnET2, with the porphyrin moiety nestling between domains IIA and IB, and the esterolytic side group oriented toward domain IIIA of HSA. Other drugs, including aspirin, bind to the same part of HSA. SnET2 does not bind to HSA when pre-incubated with aspirin, which confirms that its place of binding to this protein must be located near Lys199. This observation could be exploited to improve photo-efficiency of SnET2 by finding drugs that could compete with the photosensitizer for binding into Sudlow Site I of HSA.

Salvage external beam radiotherapy for clinical failure after cryosurgery for prostate cancer.

PURPOSE: To investigate the role of external beam radiotherapy (EBRT) as salvage treatment of prostate cancer after cryosurgery failure. METHODS AND MATERIALS: Between 1993 and 1998, 6 patients underwent EBRT with curative intent for local recurrence of prostate cancer after cryosurgery. All 6 patients had biopsy-proven recurrence and palpable disease on digital rectal examination at the time of EBRT. The median follow-up was 34 months (range 8-46). The median prostate-specific antigen level was 2.3 ng/mL (range 0.8-4.1). No patient had evidence of metastatic disease. Two patients received hormonal therapy before beginning EBRT. No patient received hormonal therapy after EBRT completion. The median elapsed time between cryosurgery and EBRT was 3 years (range 1.5-4). The median delivered dose was 66 Gy (range 62-70.2) using a 10-MeV photon beam. An in-house-developed three-dimensional treatment planning system was used to plan delivery of the prescribed dose with conformal radiotherapy techniques. RESULTS: After EBRT, all patients had complete resolution of palpable disease. Four patients (66%) were disease free at the time of the last follow-up. Two patients developed biochemical failure as defined by the American Society for Therapeutic Radiology and Oncology consensus definition. One of these patients had a prostate-specific antigen level of 97 ng/mL before cryosurgery. No patient developed distant metastasis during follow-up. Two patients (33%) developed proctitis; 1 case resolved with Rowasa suppositories and 1 required blood transfusion. CONCLUSIONS: Our preliminary results suggest that EBRT can render a significant number of patients biochemically free of disease and can cause complete resolution of clinically palpable disease after initial cryosurgery. The results also showed that EBRT can be given without excessive morbidity. EBRT should be considered as a treatment option in these potentially curable cases.

Curcumin prevents intravesical tumor implantation of the MBT-2 tumor cell line in C3H mice.

PURPOSE: The development of an effective nontoxic intravesical agent that may be used immediately after bladder tumor resection to prevent the implantation of tumor cells would be a significant clinical advancement. We report the cytotoxic effects of curcumin on bladder tumor cell lines as well as its effects on the intravesical implantation of tumor cells in C3H mice. MATERIALS AND METHODS: UMUC human and MBT-2 mouse bladder cancer lines were incubated with 0 to 100 microM. curcumin in dimethyl sulfoxide for 30 minutes and cell viability was determined by clonal assay. Additional culture dishes were incubated with curcumin and processed for electron microscopy. Using the C3H mice and the MBT2 tumor lines the effects of intravesical curcumin on tumor implantation after bladder injury was studied. The 10 group 1 mice served as nontreatment controls. In the 18 group 2 mice 30 minutes after tumor cell implantation 100 microM. curcumin in 0.1% dimethyl sulfoxide were instilled intravesically for 30 minutes. The 15 group 3 mice served as treatment controls with 0.1% dimethyl sulfoxide or culture medium instilled intravesically for 30 minutes. Animals were sacrificed 7 to 10 days after treatment and the bladder was subjected to histological analysis for tumor. RESULTS: At the 100 microM. dose curcumin was completely lethal to the 2 cell lines on clonal growth assay. Electron microscopy revealed apoptotic bodies after curcumin administration. The tumor implantation rate was 16.7% (3 of 18 mice) in curcumin treated bladders and 73% (11 of 15) in the vehicle control group. CONCLUSIONS: At the 100 microm. concentration curcumin is a potent cytotoxic agent against the MBT and UMUC bladder tumor cell lines. In addition, curcumin effectively inhibits tumor implantation and growth in this murine bladder tumor model.

Studies of tin ethyl etiopurpurin photodynamic therapy of the canine prostate.

PURPOSE: Previous studies have demonstrated the technical feasibility of destroying prostate tissue using photodynamic therapy for benign and malignant disease. A series of canine studies was performed to evaluate the systemic uptake and distribution of the photosensitizer tin ethyl etiopurpurin (SnET2) in the prostate and surrounding tissues, and determine the optimal combination of drug dose, light dose and time interval between drug and light administration using transurethral and transperineal interstitial light delivery. MATERIALS AND METHODS: Adult male mongrel source dogs received intravenous bolus injections of 0.5 or 1.0 mg./kg. SnET2 in 4 studies. In the first study the concentration of SnET2 in the prostate and surrounding tissue was measured at various time points after dosing. In the second study a tissue dose response relationship of SnET2-PDT was studied after transperineal interstitial light application. The third and fourth studies evaluated the tissue effects of combined transurethral and transperineal interstitial light application on SnET2 sensitized prostates. RESULTS: Substantial amounts of SnET2 were measured in the prostate between 24 and 168 hours after infusion. Drug and light dose dependent prostatic tissue necrosis and volume reduction were documented in the dose response relationship study. The combination of transurethral and transperineal light resulted in the extensive destruction of glandular epithelium with minimal damage to surrounding structures. Average prostate volume decreased 52%. Transperineal interstitial light delivery with multiple diffusers resulted in substantial glandular destruction of the prostate. An average volume reduction of more than 60% was achieved. CONCLUSIONS: SnET2-PDT is a viable minimally invasive treatment modality for prostate tissue destruction.

Recombinant PAI-1 inhibits angiogenesis and reduces size of LNCaP prostate cancer xenografts in SCID mice.

To understand the fundamental determinants of urokinase plasminogen activator (uPA) driven angiogenesis in cancer we studied how inhibition of uPA activity could reduce neovascularization and consequently reduce tumor size in experimental animals. Proteolytic enzymes are required to mediate tumor cell invasion to adjacent tissues and initiate the metastatic process. Many different human cancers commonly overexpress the urokinase plasminogen activator system, one of the proteolytic enzyme systems. Reduction of urokinase activity in cancer cells is evidently associated with diminished invasion and metastasis. However, it has been shown recently that inhibitors of uPA could reduce tumor size also. The mechanism of action leading to decline in tumor growth rate is not clear. Proteolysis is responsible for degradation of proteins, for invasion or metastasis, but not for the proliferate properties of the cancer cells. It is difficult to envision that diminishing the size of tumor is due to simply blocking of uPA activity of cancer cells. Instead, inhibitors of uPA may be interacting with the elements of the extracellular matrix, such the neovascular bed surrounding tumors that has been reported to contain high amounts of uPA and its receptor. Overall these data strongly suggest that inhibitors of urokinase limit cancer growth by inhibiting angiogenesis. However, it is possible also that uPA inhibitors could act on cancer cells directly or prevent angiogenesis by alternative mechanisms that are not related to uPA inhibition. Therefore, we examined if plasminogen activator inhibitor (PAI-1) could limit angiogenesis. If it does, it will provide definitive evidence of uPA/PAI-1 involvement in reduction of cancer growth. Indeed, our study demonstrates that exogenously applied 14-1b PAI-1 is a powerful inhibitor of angiogenesis in three different in vitro models and is a powerful anti-cancer agent in a SCID mice model inoculated with human LNCaP prostate cancer cells.

Curcumin inhibits lipoxygenase by binding to its central cavity: theoretical and X-ray evidence.

Many lipoxygenase inhibitors including curcumin are currently being studied for their anti-carcinogenic properties. Curcumin is a naturally occurring polyphenolic phytochemical isolated from the powdered rhizome of the plant Curcuma longa that possesses anti-inflammatory properties and inhibits cancer formation in mice. Recently it was shown that the soybean lipoxygenase L1 catalyzed the oxygenation of curcumin and that curcumin can act as a lipoxygenase substrate. In the current study, we investigated the fate of curcumin when used as a soybean lipoxygenase L3 substrate. By use of X-ray diffraction and mass spectrometry, we found an unoccupied electron mass that appears to be an unusual degradation product of curcumin (4-hydroxyperoxy-2-methoxyphenol) located near the soybean L3 catalytic site. Understanding how curcumin inhibits lipoxygenase may help in the development of novel anti-cancer drugs used for treatment where lipoxygenases are involved.

Expression of soluble urokinase plasminogen activator receptor may be related to outcome in prostate cancer patients.

The urokinase-type plasminogen activator receptor (uPAR) exists as a GPI anchored glycoprotein (Mr=50-60 kDa) on the surface of various cell types. This receptor can be bound by or cleaved by urokinase. The cleaved receptor, soluble urokinase-type plasminogen activator receptor (suPAR), with an Mr=35 kDa has no known physiological function and can be identified circulating in the blood of normal individuals. Although no function has been characterized, the soluble receptor has been reported to be of clinical significance. The objective of this study is to characterize novel serum markers that can be used for the early detection of prostate cancer and to predict patient prognosis. Thirty-nine patients at the University of Yaounde I, Yaounde, Cameroon, West Africa were examined for prostatic disorders. Of these, 46% were diagnosed with benign prostate hyperplasia (BPH), while 44% of the patients were diagnosed via biopsy with prostate cancer and graded accordingly. Here we show that serum from patients with BPH or prostate cancer contains elevated levels of suPAR. To examine the significance of suPAR as a diagnostic factor, we used a suPAR ELISA kit and compared these results with serum levels of prostate specific antigen (PSA), the current diagnostic marker for prostate cancer. PSA and serum suPAR levels in BPH and cancer patients were greatly elevated in the majority of patients, while others had undetectable levels of either. Serum levels of suPAR were high in cancer patients as well as, although to a lesser degree, in patients with BPH. Cancer patients who died during the follow-up period were found to have consistently higher serum suPAR levels than correlating serum PSA levels. These preliminary findings are the first evaluating serum suPAR levels as a possible diagnostic marker for the early detection of prostate cancer and for the prediction of patient prognosis.

Computer model for cryosurgery of the prostate.

The objective of this study was to devise an interactive tool to assist in cryoablation therapy through computer modeling, simulation, and visualization. CryoSim, a software package, accepts a set of acquired and processed three-dimensional ultrasound images, then models heat diffusion (formation of the iceball) based on numerical approximation of the heat equation and knowledge of the thermal properties of the underlying tissues. Results of cryoexperiments were found to be significantly similar to those generated by CryoSim. Therefore, CryoSim provides a viable technique for predicting the outcome of cryosurgery, and establishes a platform for future automation of cryosurgery.

Angiostatic activity of synthetic inhibitors of urokinase type plasminogen activator.

We hypothesize that tumor angiogenesis can be limited by the reduction of enzymatic activity of the urokinase type plasminogen activator. The proposed mechanism is elimination of proteolytic activity by the advancing tip of capillaries which utilize proteolysis to produce space needed for vessel expansion. To test our hypothesis, we have investigated the angiostatic activity of synthetic low molecular weight inhibitors of urokinase: amiloride, benzamidine, EGCG, B428, and B623 using the chicken embryo corioallantoic membrane (CAM) model. We found that all tested inhibitors of urokinase cause a significant reduction of angiogenesis.

Thermal lasers in urologic oncology.

Urology is a surgical specialty that relies heavily on the endoscopic approach for diagnosis and treatment of disease. Electrosurgical instruments have been the standard vehicle for endoscopic tumor ablation. Over the last 30 years a number of investigators have explored the use of the medical laser as either an alternative or an adjunct to standard electrosurgical techniques. The development of small caliber flexible and rigid endoscopic application. In addition, the potential for very limited and precise distribution of laser energy in targeted tissue is clinically appealing for endoscopic applications. In this article, we review the use of thermal laser in urologic oncology.

Effects of tacrolimus on hyperlipidemia after successful renal transplantation: a Southeastern Organ Procurement Foundation multicenter clinical study.

BACKGROUND: Tacrolimus has been shown to have a less adverse effect on the lipid profiles of transplant patients when the drug is started as induction therapy. In order to determine the effect tacrolimus has on lipid profiles in stable cyclosporine-treated renal transplant patients with established hyperlipidemia, a randomized prospective study was undertaken by the Southeastern Organ Procurement Foundation. METHODS: Patients of the 13 transplant centers, with cholesterol of 240 mg/dl or greater, who were at least 1 year posttransplant with stable renal function, were randomly assigned to remain on cyclosporine (control) or converted to tacrolimus. Patients converted to tacrolimus were maintained at a level of 5-15 ng/ml, and control patients remained at their previous levels of cyclosporine. Concurrent immunosuppressants were not changed. Levels of total cholesterol, triglycerides, total high-density lipoprotein, low-density lipoprotein (LDL), very-low-density lipoprotein, and apoproteins A and B were monitored before conversion and at months 1, 3, and 6. Renal function and glucose control were evaluated at the beginning and end of the study (month 6). RESULTS: A total of 65 patients were enrolled; 12 patients failed to complete the study. None were removed as a result of acute rejection or graft failure. Fifty-three patients were available for analysis (27 in the tacrolimus group and 26 controls). Demographics were not different between groups. In patients converted to tacrolimus treatment, there was a -55 mg/dl (-16%) (P=0.0031) change in cholesterol, a -48 mg/dl (-25%) (P=0.0014) change in LDL cholesterol, and a -36 mg/dl (-23%) (P=0.034) change in apolipoprotein B. There was no change in renal function, glycemic control, or incidence of new onset diabetes mellitus in the tacrolimus group. CONCLUSION: Conversion from cyclosporine to tacrolimus can be safely done after successful transplantation. Introduction of tacrolimus to a stable renal patient does not effect renal function or glycemic control. Tacrolimus can lower cholesterol, LDL, and apolipoprotein B. Conversion to tacrolimus from cyclosporine should be considered in the treatment of posttransplant hyperlipidemia.

Adrenocortical oncocytoma: two case reports and review of literature.

Oncocytomas of the adrenal gland are rare; only 9 cases are reported in the world literature. We report 2 new cases in which benign adrenal masses were detected during evaluation for microhematuria or flank pain. Subsequent to extirpation of the mass, pathologic examination established the diagnosis of adrenocortical oncocytoma.

Evaluation of an immunoisolation membrane formed by incorporating a polyvinyl alcohol hydrogel within a microporous filter support.

An immunoisolation membrane formed by incorporating a high water content polyvinyl alcohol (PVA) hydrogel into a microporous polyether sulfone (PES) filter has been investigated in this study. The PVA hydrogel is formed in situ within the filter pores via glutaraldehyde (GA) crosslinking under acidic conditions. The tortuous nature of the microporous filter pores securely anchors the embedded hydrogel to provide excellent structural integrity. The high void fraction of the PES filter support (>80%) and high water content of the PVA hydrogel (>85% water by weight) allow excellent solute transport rates, while an appropriate level of glutaraldehyde crosslinking supplies the required molecular size selectivity. In vitro permeability measurements made with solutes covering a wide range of molecular sizes demonstrate high transport rates for small nutrient molecules with rapidly diminishing permeabilities above a molecular weight of approximately 1,000 Dalton. Implantation experiments show that the membrane properties are not deleteriously affected by prolonged in vivo exposure or common sterilization techniques. Thus, this hybrid hydrogel/filter membrane system offers a promising approach to the immunoisolation of implanted cells.

Transperineal photodynamic ablation of the canine prostate.

PURPOSE: Experiments were undertaken to determine the effects of transperineal interstitial photodynamic therapy on the canine prostate. MATERIALS AND METHODS: Mongrel dogs were injected intravenously with the photosensitizer, tin (II) ethyl etiopurpurin dichloride. Twenty-four hours later, 2 optical fibers were implanted in 1 hemisphere of the prostate, which was then treated with red light (660 nm.). RESULTS: Acutely, the treated areas showed extensive hemorrhagic necrosis. At 3 and 6 weeks, the treated lobes were largely replaced by fibrous connective tissue. CONCLUSION: Transperineal photodynamic therapy of the canine prostate is feasible. Further preclinical investigation is warranted to determine the applicability of this approach to the treatment of localized prostate cancer.

Use of ileal urinary diversion in conjunction with intraoperative radiotherapy.

Intraoperative radiotherapy (IORT) was introduced in the 1970s as a new modality of cancer therapy. It has been especially useful after local irradiation or surgical failure. We report on the use of IORT in 13 patients with pelvic tumors requiring urinary diversion. All 13 were managed with ileal conduits. Despite the associated problems of prior abdominal procedures (11/13 patients), prior external beam radiation to the pelvis (11/13 patients), systemic chemotherapy (4/13 patients), and prolonged operative time (> 10 hours), perioperative mortality (1/13) and morbidity rates were low. We conclude that in cases of prior colonic resection and pelvic radiation, potentially irradiated ileum can be safely used for urinary diversion.

Tracer technique to measure in vivo chemical transport rates within an implantable cell transplantation device.

An in vivo tracer technique that uses radiolabeled insulin as the tracer molecule has been developed to assess the rate of chemical transport between the cell transplantation chamber of an implantable bioartificial device and the host's circulatory system. The device considered here employs site-directed neovascularization of a porous matrix to induce capillary growth adjacent to an immunoisolated cell implantation chamber. This device design is being investigated as a vehicle for therapeutic cell transplantation, with the advantages that it allows the cells to perform their therapeutic function without the danger of immune rejection and it avoids damaging contact of blood flow with artificial surfaces. A pharmacokinetic model of the mass transport between the implantation chamber, the vascularized matrix, and the body has been devised to allow proper analysis and understanding of the experimental tracer results. Experiments performed in this study have been principally directed at evaluation of the tracer model parameters, but results also provide a quantitative measure of the progression of capillary growth into a porous matrix. Measured plasma tracer levels demonstrate that chemical transport rates within the implanted device increase with the progression of matrix vascular ingrowth. Agreement between the fitted model curves and the corresponding measured concentrations at different levels of capillary ingrowth demonstrate that the model provides a realistic representation of the actual capillary-mediated transport phenomena occurring within the device.

The effect of transurethral light on the canine prostate after sensitization with the photosensitizer tin (II) etiopurpurin dichloride: a pilot study.

A pilot study was undertaken to determine the effect of transurethral light on photosensitized periurethral prostatic tissue in the dog. Initial studies demonstrated that a sufficient level of the photosensitizer tin (II) etiopurpurin dichloride, SnET2, was present in the canine prostate 24 hours after intravenous administration to create a photodynamic effect. Gross and histologic examination of SnET2 photosensitized prostates treated transurethrally with 285 joules per cm. of red light (660 nm.) showed hemorrhagic necrosis as much as 1 cm. from the urethral wall. Three weeks after treatment, circumferential glandular atrophy was evident within the treatment area. The urethral mucosa, which was histologically absent at the 48-hour interval, regenerated by 3 weeks. Transurethral photodynamic treatment of the prostate is feasible, and its use for the treatment of benign prostatic hyperplasia warrants further investigation.

Photochemical ablation of intestinal mucosa for bladder augmentation.

Complications associated with enterocystoplasty include mucus production, electrolyte abnormalities, infections, stones and cancer at the vesicoenteric anastomosis. Removal of the intestinal mucosa with subsequent urothelialization may obviate these problems. We describe a unique approach whereby photodynamic therapy is used to de-epithelialize an ileal segment before augmentation. Enterocystoplasty was performed in 32 female Fischer 344 rats using a 1.5 cm. patch of terminal ileum. Of the 32 rats 24 survived at least 6 weeks before euthanasia. The experimental group (10 rats) received hematoporphyrin derivative intravenously 24 hours before surgery. The ileal patch was treated with red light for 20 minutes and then used for augmentation. There were 3 control groups, including 1 group of 5 rats that underwent augmentation alone, while the other 2 groups were augmented but received either light treatment (4 rats) or hematoporphyrin derivative (5 rats). Histological analysis revealed urothelialization of the augments treated with hematoporphyrin derivative and light, which did not occur in the controls. The preoperative and postoperative bladder capacities increased substantially in all groups. Mucus production and bacterial colonization were reduced while stone formation increased in the treated animals.