Tracer Technique to Measure in Vivo Chemical Transport Rates within an Implantable Cell Transplantation Device

An in vivo tracer technique that uses radiolabeled inulin 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.

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.

From the battlefield to the bladder: The development of thioTEPA

Effective medications for the treatment of cancer were nonexistent in the early twentieth century. Ironically the widespread use of toxic chemical weapons, chlorine and sulfur mustard gas, during the “Great War” led to the first successful chemotherapeutic treatment of cancer patients. Soon after the introduction of poisonous gas on the battlefield, reports of the resulting pancytopenia in exposed combatants appeared in the medical literature. The biologic effect of chemical weaponry on rapidly dividing cells eventually was recognized for its salutary potential in the treatment of cancer. Once this potential was appreciated, hundreds of similar compounds were synthesized and evaluated as chemotherapeutic agents. One such compound, thioTEPA, would eventually open the era of intravesical treatment of urothelial cancer.

Epigallocatechin-3-gallate prevents tumor cell implantation/growth in an experimental rat bladder tumor model

The aim of this study was to determine the efficacy of epigallocatechin-3-gallate (EGCG) (Polyphenon E®) in comparison with mitomycin C (MMC) to prevent tumor cell implantation/growth in an animal model of superficial bladder cancer and search for possible mechanism(s) of action. Female Fisher 344 rats were used to study the effects of EGCG and mitomycin C for the prevention of transitional cell tumor implantation (AY-27). Twenty rats served as a control, tumor implantation and saline wash only. Sixty rats were treated with EGCG (100, 200 and 400 µM) intravesically for 60 or 120 min after tumor implantation. Thirty other rats were divided equally and pretreated with 400 µM EGCG or saline for 120 min before tumor initiation. In a separate series of experiments, 30 rats were treated 2 weeks after tumor initiation with saline or EGCG (400 µM). In a different experiment 39 rats were treated with: saline (n=10) EGCG (n=9) 400 µM, MMC (n=10) 0.5 µM, MMC (n=10) 400 µM. Rats were sacrificed 3 weeks following treatment. Gross and histological analyses were performed on the bladders. EGCG and mitomycin C prevented intravesical tumor growth in a concentration- and time-dependent manner. EGCG pretreatment or treatment 2 weeks post tumor implantation did not have therapeutic effects. Molecular modeling suggests that EGCG inhibits urokinase and matrix metalloproteinase-9. EGCG prevents intravesical tumor implantation/growth with a slightly better efficacy than mitomycin C in this experimental model. The data suggest that EGCG lowers proteolytic activity and lowers probability of cancer cell implantation rather than direct cancer cell killing.

Voronoff to virion: 1920s testis transplantation and AIDS

BACKGROUND

We address accusations linking AIDS with testis transplantation performed by a French surgeon, Serge Voronoff (1866-1951), and their implications in the future of animal-to-human organ transplantation.

METHODS

Biographical literature on Voronoff and scientific literature on xenotransplantation and the origin of HIV were reviewed.

RESULTS

IN the 1920s, Serge Voronoff transplanted testes from primates into humans to revitalize them sexually and physically, making him one of the first surgeons to perform xenotransplantation-transplanting live tissues between species. In recent years, some have postulated that Voronoff's transplants may have caused or contributed to the AIDS epidemic. However, consensus among virologists holds that HIV most likely originated from a chimpanzee virus known as simian immunodeficiency viruses (SIV) which many agree was transmitted to humans during the hunting of primates in the early 1900s. As these accusations have never been addressed, evidence is reviewed which refutes the claims. HIV isolate studies are summarized, which show that SIV was most likely transferred to humans from a chimpanzee species different from those used by Voronoff. Furthermore, literature suggests that Voronoff's experiments were performed in Europe and the United States, not central Africa.

CONCLUSIONS

Over 100,000 people await organ transplants, making the prospect of using animal organs to meet demand increasingly favorable. The accusations against Voronoff and others have led to increased concern over cross-species disease transfer. The evidence presented refutes those claims and is used to explain the need for further research into xenotransplantation.

A comparative study of the inhibiting effects of mitomycin C and polyphenolic catechins on tumor cell implantation/growth in a rat bladder tumor model

PURPOSE

Mitomycin C (Novaplus®) is often instilled intravesically in the postoperative period to prevent tumor cell implantation/regrowth after transurethral tumor resection. In an earlier study EGCG prevented tumor cell implantation/growth in an experimental bladder tumor model simulating clinical transurethral bladder resection. We compared the efficacy of EGCG (Polyphenon E®) to that of mitomycin C to prevent tumor cell implantation/growth in this model.

MATERIALS AND METHODS

Mitomycin C and EGCG were studied for their in vitro and in vivo effects. The AY-27 rat urothelial tumor cell line was used for in vitro and in vivo studies. In vitro cell viability studies included trypan blue exclusion, MTT proliferation assay and clonal growth assay. Fischer 344 female rats were used for intravesical tumor implantation/growth assay using an electrocautery injury model. Tumor growth in vivo was assessed in controls treated with phosphate buffered saline and in bladders treated with mitomycin C or EGCG by standard histological techniques using hematoxylin and eosin 4 weeks after injury.

RESULTS

Mitomycin C and EGCG showed cytotoxicity on all in vitro assays. They were equivalent for preventing intravesical tumor growth.

CONCLUSIONS

EGCG prevents intravesical tumor growth with efficacy equivalent to that of mitomycin C in this experimental model.

Systemic or topical application of plasminogen activator inhibitor with extended half-life (VLHL PAI-1) reduces bleeding time and total blood loss

Civilian and military trauma patients consist of a disproportional number of young people, causing a considerable burden to society in terms of disability and premature death. Hemorrhage is a leading cause of mortality in this group of patients and the novel methods to reduce bleeding would be welcomed. Management of bleeding following major trauma includes hemostatic agents that offer effective clotting. However a very limited number of agents control secondary bleeding triggered by lysis of the clot. Fibrinolysis depends on the balance between tissue plasminogen activator (tPA), activating plasminogen to plasmin initiating fibrinolysis, and plasminogen activator inhibitor type 1 (PAI-1) inhibiting tPA and preventing lysis. The drugs available on the market that prevent the activation of plasminogen have been used successfully, but have some side effects and limited efficacy for the control of localized bleeding in the surgical setting. Inhibitors of tPA, initiator of clot fibrinolysis, have not yet found their way into the clinical arena. Plasminogen activator inhibitor-1, the major specific inhibitor of tPA, can be used to limit fibrinolysis. Unfortunately, PAI-1 has a short half-life of approximately 2 h and is rapidly converted to the latent form. A recombinant PAI-1 with very long half-life developed in our laboratory (a two-point mutant, VLHL PAI-1, half-life over 700 h) has clinical potential as an agent to promote hemostasis in several scenarios including surgical injury, trauma, and PAI-1 deficiency. Here we report testing of VLHL PAI-1 as a potent inactivator of fibrinolysis reducing total blood loss while applied systemically or topically in experimental animals. The very long half-life of VLHL PAI-1 may provide an advantage in the important physiological mechanism to protect clots from premature dissolution, when applied topically or systemically to prevent excessive bleeding in the surgical and trauma setting and possibly in PAI-1 deficient patients.

Laparoscopic management of extensive ureteral fibroepithelial polyps

Fibroepthelial polyps are uniformly benign tumors of the collecting system which may cause obstruction of an affected renal unit. We present a unique case of a 34-year-old male with a solitary functioning kidney who presented with flank pain and renal insufficiency. Radiographic and ureteroscopic evaluation revealed ureteral obstruction due to extensive polyps. After ureteral stenting and normalization of renal function, successful polyp excisions were performed laparoscopically through a ureterotomy. The pathology revealed benign fibroepithelial polyps. The patient remained asymptomatic until 3 years later when ureteroscopy performed for a calculus revealed a widely patent lumen free of polyps. To our knowledge, this is the first published report of a long term follow up after laparoscopic resection of extensive ureteral fibroepithelial polyps.

Very long half-life plasminogen activator inhibitor type 1 reduces bleeding in a mouse model

OBJECTIVE

To investigate the potential for the future clinical use of a very long half-life plasminogen activator inhibitor type 1 (VLHL PAI-1) as a haemostatic agent.

MATERIALS AND METHODS

We developed a VLHL PAI-1 (half-life >700 h) recombinant mutant of PAI-1 and assessed VLHL PAI-1 for its ability to inhibit fibrinolysis in vitro using human, rabbit, mouse and rat blood. Fibrin clot lysis time, monitored by thromboelastometry, was determined at various concentrations of VLHL PAI-1. Also, we determined total bleeding time and total blood loss of control, VLHL PAI-1-, tissue-type plasminogen activator (tPA)- and tPA + VLHL PAI-1-treated mice.

RESULTS

Using a thromboelastometer, mouse blood was most similar to human blood in its coagulation and fibrinolytic characteristics. We evaluated the affect of VLHL PAI-1 on haemostasis using the mouse model and showed that VLHL PAI-1 is an effective inhibitor of fibrin clot degradation. It reduced time of bleeding and total blood loss.

CONCLUSION

VLHL PAI-1 may provide an important physiological mechanism to protect clots from premature dissolution in surgical and trauma settings.

Highly stable plasminogen activator inhibitor type one (VLHL PAI-1) protects fibrin clots from tissue plasminogen activator-mediated fibrinolysis

Plasminogen activator inhibitor-1 (PAI-1) is the major specific inhibitor of tissue-type plasminogen activator (tPA) which mediates fibrin clot lysis through activation of plasminogen. Wild-type-PAI-1 (wPAI-1) is rapidly converted to the latent form (half-life of approximately 2 h) and loses its ability to inhibit tPA. We developed a very long half-life PAI-1 (VLHL PAI-1), a recombinant protein with a half-life >700 h compared with wPAI-1. In this study, VLHL PAI-1 was assessed for its ability to inhibit clot lysis in vitro. Clot formation was initiated in normal plasma supplemented with tPA by the addition of either tissue factor or human recombinant FVIIa. Clot lysis time, monitored turbidimetrically in a microtiter plate reader, was determined at various concentrations of wPAI-1 and VLHL PAI-1. Both wPAI-1 and VLHL PAI-1 caused a significant increase in clot lysis time, although the latter was somewhat less effective at lower concentrations. The VLHL PAI-1, but not wPAI-1, maintained its anti-fibrinolytic activity after preincubation overnight at 37 degrees. These studies demonstrate that VLHL PAI-1 is an effective inhibitor of fibrin clot degradation. Due to the high stability of VLHL PAI-1 compared with wPAI-1, this novel inhibitor of tPA-mediated fibrinolysis may have therapeutic applications for treating surgical and trauma patients when used directly or in conjunction with the procoagulant recombinant FVIIa.

Replacement of intestinal mucosa with urothelium in rat augmented bladders using intravesical photodynamic therapy with 5-aminolaevulinic acid

PURPOSE

We evaluated the efficacy of intravesical aminolevulinic acid (delta-aminolevulinic acid hydrochloride) (Frontier Scientific, Logan, Utah) and photodynamic therapy for the removal of small intestinal mucosa in augmented bladders in a rat model.

MATERIALS AND METHODS

Enterocystoplasty was performed in 70 female rats using a patch of terminal ileum. A total of 28 were used to determine the pharmacokinetics (0.3, 0.6 and 0.9 M) and dwell time (30, 60 and 90 minutes) of intravesically administered aminolevulinic acid to optimize intestinal mucosal absorption and minimize bladder mucosal absorption. The remaining augmented rats were treated with intravesical photodynamic therapy at light doses of 75, 100 and 125 J. Ileal and bladder tissues were evaluated by light microscopy. Cystometric studies to evaluate bladder volume were measured before and after photodynamic therapy.

RESULTS

The concentration of 0.3 M aminolevulinic acid with a dwell time of 30 minutes resulted in an average +/- SE bowel-to-bladder concentration of 2,156 +/- 269/749 +/- 62 ng/gm (ratio 2.9:1). After photodynamic therapy histology revealed uniform ablation and replacement of the intestinal mucosa with urothelium and minimal damage to the bladder wall at all light doses. Bladder cystometry revealed no significant change in bladder capacity after photodynamic therapy.

CONCLUSIONS

In the rat model intravesical aminolevulinic acid and photodynamic therapy resulted in the replacement of intestinal mucosa with urothelium, leaving the underlying muscular layer intact. This could potentially be a viable option for patients with a preexisting bladder augment.

PAI-1 induces cell detachment, downregulates nucleophosmin (B23) and fortilin (TCTP) in LnCAP prostate cancer cells

Plasminogen activator inhibitor (PAI-1) is an anticancer agent that inhibits plasmin driven proteolysis, limiting angiogenesis and metastasis. In low concentrations it could induce cancer cell motility by interacting with urokinase (uPA), its receptor (uPAR), vitronectin and integrins. Active PAI-1 binds to uPA forming a complex with uPAR, while the latent form of PAI-1 does not. PAI-1 is found in both forms in the circulation. It is not clear which form acts as an anticancer agent and how it interacts with malignant cells. To investigate how these forms reduce angiogenesis or metastasis, we have created PAI-1 cysteine mutants in the active conformation (VLHL PAI-1) with an extended half-life that reaches approximately 700 h and its R369A mutant, which has an active conformation but cannot bind to uPA (VLHLNS PAI-1). Both VLHL PAI-1s convert into the latent form when treated with a reducing agent (DTT) that breaks disulfide bridges. Unexpectedly, during routine investigation of LnCAP cell proliferation, we have found that cells detach from the culture vessels regardless of PAI-1 conformation or activity. Further investigation showed that treatment of cancer cells with VLHL PAI-1 downregulated nucleophosmin, while all forms of PAI-1 downregulated fortilin. These two proteins are implicated in important cellular processes (cell growth, cell cycle, malignant transformation). This suggests that PAI-1, in addition to its well-known anticancer properties, plays an important role in cell signaling. We hope that by exploring PAI-1's structure and function we might be able to understand and separate the different effects of PAI-1 on cancer cells and develop more effective therapeutic strategies in cancer treatment.

Nutraceutical inhibitors of urokinase: potential applications in prostate cancer prevention and treatment

Epidemiological studies have shown that the clinical incidence of prostate cancer varies by geographical area. When individuals move from low to high prostate cancer incidence areas, the risk of developing cancer increases to the level observed in the indigenous population. It was hypothesized that this observation is related to diet or more specifically to nutraceuticals present in food, medicinal plants, and herbs. Nutraceuticals can inhibit or downregulate enzymes critical for cancer formation. We tested this hypothesis by searching the 3D database of nutraceuticals and docking them to the 3D structure of urokinase. In addition to nutraceuticals, the data-base contains known uPA inhibitors that served as positive controls. From >1,000 compounds, several potential uPA inhibitors have been selected (antipain, leupeptin, folic acid, rosmarinic acid, lavendustin A, fisetin, myricetin, tolfenamic acid). Some of these were subject to further tests on inhibitory activity and inhibition of sprout formation. We found that compounds selected by computational methods indeed inhibit uPA and sprout formation. However, because the database of nutraceuticals was small, we did not expect to find either many or high affinity/specific inhibitors. Rather, we tested this method as a proof of concept. All the facts described above support the hypothesis that nutrients selected by computerized searches can inhibit unwanted uPA activity and thus reduce angiogenesis. If true, a proper diet rich in uPA-inhibiting nutraceuticals might support the prevention of prostrate cancer and be a supportive tool in prostate cancer treatment.

Intraperitoneal Chemotherapy for the Prevention of Transitional Cell Carcinoma Implantation

PURPOSE

Tumor spillage from bladder perforation during transurethral resection of a bladder tumor or during cystectomy risks seeding the peritoneum with TCC. Current therapy is irrigation with sterile water with an unknown extent of clinical benefit. Intraperitoneal chemotherapy for other human cancers has demonstrable benefit but to our knowledge it has never been investigated for TCC. We investigated whether intraperitoneal chemotherapy can prevent TCC implantation in a murine model of tumor spillage and whether water irrigation is beneficial.

MATERIALS AND METHODS

Laparotomy was performed in 28 Fischer 344 rats (National Cancer Institute, Frederick, Maryland) to instill 1 x 10 AY-27 TCC cells. Mitomycin (10 mg/m) was instilled in 9 rats and saline was used in the control group. A third group underwent lavage with sterile water. At sacrifice after 2 weeks tumors were measured in mm and weighed. A followup experiment of 4-week survival used 5 mg/m mitomycin and added a fourth group treated with water lavage plus mitomycin.

RESULTS

All 9 rats in the saline control group had gross tumors at the laparotomy site as well as gross carcinomatosis. The 10 water lavage rats also demonstrated gross tumors but of smaller size (p = 0.02). All rats treated with mitomycin had no gross or microscopic evidence of tumor growth anywhere in the peritoneum. In experiment 2 none of the rats treated with lower dose mitomycin had gross or microscopic tumors regardless of water lavage.

CONCLUSIONS

Intraperitoneal chemotherapy prevents TCC implantation in a murine model of tumor spillage. Water lavage decreases the tumor burden but it cannot effectively sterilize the peritoneum of tumor.

Synthetic curcuminoids modulate the arachidonic acid metabolism of human platelet 12-lipoxygenase and reduce sprout formation of human endothelial cells

Platelet 12-lipoxygenase (P-12-LOX) is overexpressed in different types of cancers, including prostate cancer, and the level of expression is correlated with the grade of this cancer. Arachidonic acid is metabolized by 12-LOX to 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE], and this biologically active metabolite is involved in prostate cancer progression by modulating cell proliferation in multiple cancer-related pathways inducing angiogenesis and metastasis. Thus, inhibition of P-12-LOX can reduce these two processes. Several lipoxygenase inhibitors are known, including plant and mammalian lipoxygenases, but only a few of them are known inhibitors of P-12-LOX. Curcumin is one of these lipoxygenase inhibitors. Using a homology model of the three-dimensional structure of human P-12-LOX, we did computational docking of synthetic curcuminoids (curcumin derivatives) to identify inhibitors superior to curcumin. Docking of the known inhibitors curcumin and NDGA to P-12-LOX was used to optimize the docking protocol for the system in study. Over 75% of the compounds of interest were successfully docked into the active site of P-12-LOX, many of them sharing similar binding modes. Curcuminoids that did not dock into the active site did not inhibit P-12-LOX. From a set of the curcuminoids that were successfully docked and selected for testing, two were found to inhibit human lipoxygenase better than curcumin. False-positive curcuminoids showed high LogP (theoretical) values, indicating poor water solubility, a possible reason for lack of inhibitory activity or/and nonrealistic binding. Additionally, the curcuminoids inhibiting P-12-LOX were tested for their ability to reduce sprout formation of endothelial cells (in vitro model of angiogenesis). We found that only curcuminoids inhibiting human P-12-LOX and the known inhibitor NDGA reduced sprout formation. Only limited inhibition of sprout formation at approximately IC(50) concentrations has been seen. At IC(50), a substantial amount of 12-HETE can be produced by lipoxygenase, providing a stimulus for angiogenic sprouting of endothelial cells. Increasing the concentration of lipoxygenase inhibitors above IC(50), thus decreasing the concentration of 12(S)-HETE produced, greatly reduced sprout formation for all inhibitors tested. This universal event for all tested lipoxygenase inhibitors suggests that the inhibition of sprout formation was most likely due to the inhibition of human P-12-LOX but not other cancer-related pathways.

Vascular endothelial growth factor production in human prostate cancer cells is stimulated by overexpression of platelet 12-lipoxygenase

BACKGROUND

Elevated platelet 12-Lipoxygenase (P12-LOX) expression is associated with advanced stage and grade prostate cancer and overexpression in PC-3 cells promotes tumor growth and angiogenesis. The mechanisms underlying the role of P12-LOX in angiogenesis remain unclear.

METHODS

Enzyme linked immunosorbent assays were used to measure 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE) and vascular endothelial growth factor (VEGF) in conditioned media of PC-3 cells stably overexpressing human P12-LOX. Immunoblotting was used to observe stimulation of signal transduction in prostate cancer cell lines following exposure to 12(S)-HETE.

RESULTS

P12-LOX overexpression promotes increased accumulation of 12(S)-HETE and VEGF in culture media leading to constitutive ERK1/2 phosphorylation. 12(S)-HETE stimulates ERK1/2 phosphorylation via a pertussis toxin sensitive G-protein coupled receptor (GPCR) and MEK; the inhibition of which reduces VEGF accumulation by 36% and 70%, respectively.

CONCLUSIONS

Our data provide insight into a possible mechanism by which prostate cancer cells with elevated expression of P12-LOX stimulate VEGF production, thus increasing their angiogenic potential.

Plasminogen activator inhibitor-1 is locked in active conformation and polymerizes upon binding ligands neutralizing its activity

Plasminogen activator inhibitor-1 (PAI-1), a member of the serpin super-family, forms a covalent complex with its target proteinases, such as tissue and urokinase plasminogen activators. Thus, PAI-1 controls the physiological and pathological proteolysis. An abnormal expression of PAI-1 has been observed in different diseases, which can be treated by returning the proteolysis back to normal physiological levels. It has been reported that some PAI-1 inhibitors neutralize its activity by accelerating the conversion of PAI-1 into a latent form. We have found small organic chemicals that also neutralize PAI-1 activity, but by a different mechanism. Using the NBD fluorescent probe [N,N'-dimethyl-N-(acetyl)-N'-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)] incorporated into the reactive center loop (RCL) of PAI-1, we measured the kinetics of conversion from an active to a latent form. Unexpectedly, we found that some inhibitors of PAI-1 arrest this serpin in its active form instead of increasing the speed of conversion. Using docking calculations, we located two possible binding sites for these chemicals. The sites are in proximity of the P1/P1' amino acids of the RCL of PAI-1. Binding in this area can inactivate PAI-1 and additionally create a steric obstacle on the RCL making insertion of this loop between the A3 and A5 strands more difficult; hence abolishing a necessary step in the conversion of this protein into the latent form. Additionally, PAI-1 inhibitors link the RCL of one PAI-1 molecule with the strand 3C and strand 4C or helix A and strand 1B regions of the other PAI-1 molecule aiding polymerization or stabilizing the junction of the two. The polymerization of PAI-1 reduces PAI-1 activity by encapsulating the critical RCL fragment inside the formed PAI-1/PAI-1 polymers.

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.

Diverse optical characteristic of the prostate and light delivery system: implications for computer modelling of prostatic photodynamic therapy

OBJECTIVE

To explore the use of photodynamic therapy (PDT) as a minimally invasive form of treatment for organ-confined prostate cancer, for although there are several therapies, ablative treatments are associated with significant morbidity.

MATERIALS AND METHODS

Using the photosensitizer tin etiopurpurin, dogs were treated with interstitially placed laser fibres in an effort to validate PDT for treating prostate cancer. Earlier models assumed a uniform distribution of light output from a cylindrical fibre and a uniform attenuation coefficient throughout the prostate. Subsequent observations show that this model was too simple and that light radiance is not linear. To overcome under-treatment, a computer program to complement real-time fibre placement was developed.

RESULTS

As light radiance from interstitially placed laser fibres varies significantly from the commonly assumed ideal cylindrical emission, a predictive mathematical model of prostate PDT needs to consider the real emission. Also, the optical properties of the prostate, e.g. absorption and scattering of light, are anisotropic. Differences in the attenuation coefficient (combining absorption and scattering of light) also varied among different animals. Incorporating all these variables into a computer program produced a virtual model of the photo-ablated zone within +/- 2 mm of that observed in animals.

CONCLUSION

PDT of the prostate is not trivial and should benefit from computer-aided methods as it is developed for clinical use.

Transperineal in vivo fluence-rate dosimetry in the canine prostate during SnET2-mediated PDT

Advances in photodynamic therapy (PDT) treatment for prostate cancer can be achieved either by improving selectivity of the photosensitizer towards prostate gland tissue or improving the dosimetry by means of individualized treatment planning using currently available photosensitizers. The latter approach requires the ability to measure, among other parameters, the fluence rate at different positions within the prostate and the ability to derive the tissue optical properties. Here fibre optic probes are presented capable of measuring the fluence rate throughout large tissue volumes and a method to derive the tissue optical properties for different volumes of the prostate. The responsivity of the sensors is sufficient to detect a fluence rate of 0.1 mW cm(-2). The effective attenuation coefficient in the canine prostate at 660 nm is higher at the capsule (2.15+/-0.19 cm(-1)) than in proximity of the urethra (1.84+/-0.36 cm(-1)). Significant spatial and temporal intra- and inter-canine variability in the tissue optical properties was noted, highlighting the need for individualized monitoring of the fluence rate for improved dosimetry.

In vivo and in vitro effect of baicalein on human prostate cancer cells

We investigated the in vitro effects of baicalein and baicalin on human umbilical vein endothelial cells (HUVECs) and on human prostate tumor cells (DU-145 and PC3) as well as the effect of orally administered baicalein on the growth of DU-145 cells after subcutaneous injection into SCID mice. In vitro effects of baicalein and baicalin treatment on human prostate cancer cell lines DU-145 and PC-3 were assessed by employing cell proliferation (MTS) assay, cytotoxicity (LIVE/DEAD) assay, and TUNEL assay. In vitro anti-proliferative and anti-angiogenic properties of baicalein and baicalin were studied on HUVECs by sprout assay. The effect of orally administered baicalein on tumor growth in SCID mice was studied in four groups (n=10) of animals injected subcutaneously with DU-145 cells and treated daily for 28 days. The control group received only vehicle (carboxymethylcellulose), whereas the other three groups received escalating doses of baicalein (10, 20, and 40 mg/kg per day). Baicalein and baicalin exhibit dose-dependent growth inhibitory effects on human prostate cancer cells and umbilical vein endothelial cells in vitro. Also, treatment by these two flavonoid compounds significantly decreased the average number and length of sprouts formed by the endothelial cell aggregates in a dose-dependent manner. In vivo, treatment of mice with baicalein demonstrated a statistically significant tumor volume reduction (p<0.01) when compared to the control. This is the first study demonstrating an in vivo growth inhibitory effect of orally administered baicalein on human prostate tumors in mice.

Plasminogen activator inhibitor type-1 mutants regulate angiogenesis of human umbilical and lung vascular endothelial cells

Plasminogen activator inhibitor type-1 (PAI-1) is considered one of the key regulators of tumor invasion, metastasis, as well as cancer-related angiogenesis. The literature suggests that PAI-1 plays a dual role in these processes because it inhibits plasmin-originated proteolysis and binds to vitronectin or integrins. Stimulation or inhibition of angiogenesis largely depends on which of these elements PAI-1 interacts. Wild PAI-1 converts quickly into its latent, inactive form and loses its anti-proteolytic activity, but still binds to vitronectin and integrins. Thus we constructed PAI-1s with extended half-life to prolong their anti-proteolytic activity. We have analyzed the effects of sprout formation inhibition by PAI-1s on two functionally different endothelial cell (EC) systems, human umbilical vein endothelial cells (HUVEC), expressing moderate amounts of urokinase (uPA), and human lung microvascular endothelial cells (HLMVEC), expressing high amounts of this enzyme. We have used wild-type PAI-1 (wPAI-1) (t(1/2) = 1.6 h) and PAI-1 cysteine mutants (CysPAI-1) characterized by their prolonged half-life time (hDbetaT) (t(1/2) = 63.6 h and t(1/2) = 7,000 h). We have observed a significant inhibitory dose-dependent effect exerted by the CysPAI-1s on sprout formation by HUVEC and HLMVEC cells. The inhibition rate was considerably stronger in lung capillary cell cultures and significantly more pronounced for CysPAI-1 mutants with longer anti-uPA activity (betaT). wPAI-1 with a short anti-proteolytic half-life has induced sprout formation in HUVEC, but not in HLMVEC cultures. This difference in behavior was most likely related to the presence of excessive amounts of uPA in HLMVEC cells and the known mechanism of clearing PAI-1/uPA/uPAR complexes from the cell surface. A less efficient system of HUVEC cells might give wPAI-1 the chance to interact with non-proteolytic pathways of angiogenesis stimulation. We conclude that while the anti-proteolytic properties of PAI-1 constructs are preserved, these proteins inhibit angiogenesis and inhibitory activity dominates over any stimulatory effects of PAI-1.

OPTICAL CHARACTERISTICS OF THE CANINE PROSTATE AT 665 NM SENSITIZED WITH TIN ETIOPURPURIN DICHLORIDE: NEED FOR REAL-TIME MONITORING OF PHOTODYNAMIC THERAPY

PURPOSE

Photodynamic therapy (PDT) is an emerging, minimally invasive therapy for prostate cancer that depends on the sequestration of a photosensitizing drug within targeted tissue. The photosensitizer is subsequently activated by light of a specific wavelength, resulting in destruction of the targeted tissue. Successful treatment requires knowledge of the optical properties of the target tissue, a critical element for therapy.

MATERIALS AND METHODS

Adult canines were injected with tin etiopurpurin dichloride (1.0 mg/kg) as a liposome emulsion vehicle in saline 24 hours prior to light treatment. Laser light was delivered to the prostate via a 400 microm optical fiber fitted with a 2.0 cm cylindrical diffuser and optical properties of the prostate were measured.

RESULTS

In this study we determined the attenuation coefficient and critical fluence in the canine prostate. Our studies shown that the attenuation coefficient is not uniform but higher at the base (average for all animals 2.59 to 2.79 cm-1) than in the mid section or apex of the prostate (1.71 to 1.90 cm-1). Significant differences among dogs (0.11 to 12.70 cm-1) were found. In some cases we observed a fluctuation of the attenuation coefficient during treatment. We also established experimentally the minimum energy (1449 mJ/cm2) needed (critical fluence) to produce necrosis. Experimentally establishing the values of effective attenuation and critical fluence is necessary to predict the area of ablation during PDT and protect surrounding organs from over treatment.

CONCLUSIONS

Based on our results it is evident that for PDT of the prostate to be successful the optical parameters of the prostate must be measured and monitored during treatment. We suggest that the optimum way of doing this is real-time computerized monitoring combined with simulation PDT.

Lipoxygenase interactions with natural flavonoid, quercetin, reveal a complex with protocatechuic acid in its X-ray structure at 2.1 A resolution

PUFA metabolites have a profound effect on inflammatory diseases and cancer progression. Blocking their production by inhibiting PUFA metabolizing enzymes (dioxygenases: cyclooxygenases and LOXs) might be a successful way to control and relieve such problems, if we learn to better understand their actions at a molecular level. Compounds with strong antioxidative and free radical scavenging properties, such as polyphenols, could be effective in blocking PUFA activities, and natural flavonoids possess such qualities. Quercetin belongs to the group of natural catecholic compounds and is known as a potent, competitive inhibitor of LOX. Structural analysis reveals that quercetin entrapped within LOX undergoes degradation, and the resulting compound has been identified by X-ray analysis as protocatechuic acid (3,4-dihydroxybenzoic acid) positioned near the iron site. Its C3-OH group points toward His523, C4-OH forms a hydrogen bond with O=C from the enzyme's C-terminus, and the carboxylic group is incorporated into the hydrogen bonding network of the active-site neighborhood via Gln514. This unexpected result, together with our previous observations concerning other polyphenols, yields new evidence about the metabolism of natural flavonoids. These compounds might be vulnerable to the co-oxidase activity of LOX, leading to enzyme-stimulated oxidative degradation, which results in an inhibitor of a lower molecular weight.

Inhibition of bladder tumor growth by the green tea derivative epigallocatechin-3-gallate

PURPOSE

We evaluated the green tea derivative epigallocatechin-3-gallate (EGCG) as an intravesical agent for the prevention of transitional cell tumor implantation.

MATERIALS AND METHODS

In vitro studies were performed in the AY-27 rat transitional cell cancer and the L1210 mouse leukemia cell lines. Cells were exposed to increasing concentrations of EGCG for 30 minutes to 48 hours. Surviving cell colonies were then determined. A DNA ladder assay was performed in the 2 cell lines. Fisher 344 rats were used for in vivo studies with an intravesical tumor implantation model. Group 1 (12 rats) served as a control (tumor implantation and medium wash only). In group 2 (28 rats) 200 microM EGCG were instilled intravesically 30 minutes after tumor implantation. Rats were sacrificed 3 weeks following treatment. Gross and histological analyses were then performed on the bladders.

RESULTS

At 6.0 x 104 cells per 100 mm dish a time dose dependent response was observed. After 2 hours of treatment with EGCG 100% cell lethality of the AY-27 cell line occurred at concentrations greater than 100 microM. Strong banding on the DNA ladder assay was seen with the L1210 mouse leukemia cell line. Only weak banding patterns were found in the AY-27 cell line treated with EGCG (100 and 200 microM) for 24 hours. All 12 controls were successfully implanted with tumors. In group 2 (EGCG instillation) 18 of the 28 animals (64%) were free of tumor (Fisher's exact test p = 0.001).

CONCLUSIONS

The clonal assays showed a time dose related response to EGCG. Intravesical instillation of EGCG inhibits the growth of AY-27 rat transitional cells implanted in this model.

Structure of curcumin in complex with lipoxygenase and its significance in cancer

Scientific research provides documented evidence that fatty acid metabolites have profound impact on carcinogenesis. Intervention into dioxygenase pathways might therefore effect development, metastasis and progression of many types of cancers. This work delivers the first 3D structural data and explains how curcumin interacts with the fatty acid metabolizing enzyme, soybean lipoxygenase. Curcumin binds to lipoxygenase in a non-competitive manner. Trapped in that complex, it undergoes photodegradation in the X-rays, but utilizes enzyme catalytic ability to form the peroxy complex Enz-Fe-O-O-R as 4-hydroperoxy-2-methoxy-phenol, that later transforms into 2-methoxycyclohexa-2,5-diene-1,4-dione. Our observations about this radiation and time-dependent inhibition add new information to the role that curcumin might play in cancer prevention and treatment.

Spatial distribution of liposome encapsulated tin etiopurpurin dichloride (SnET2) in the canine prostate: implications for computer simulation of photodynamic therapy

Photodynamic therapy (PDT) is a minimally invasive treatment that can be employed in many human diseases including prostate cancer. PDT for prostate cancer depends on the sequestration of a photosensitizing drug within the glandular tissue. The photosensitizer is subsequently activated by light (usually from a laser) and the active drug destroys tissue. Since prostate cancer is a multifocal disease, PDT must ablate the glandular prostate completely. This will depend on the precise placement of light sources in the prostate and delivery of a therapeutic light dose to the entire gland. Also, sources of light and their spatial distribution must be tailored to each individual patient. The uniform, therapeutic light distribution can be achieved by interstitial light irradiation. In this case, the light is delivered by diffusers placed within the substance of the prostate parallel to the urethra at a distance optimized to deliver adequate levels of light and to create the desired photodynamic effect. To help achieve the uniform light distribution throughout the prostate we have developed a computer program that can determine treatment effects. The program predicts the best set of parameters and the position of light diffusers in space, and displays them in graphical or in numerical form assuming a fixed attenuation coefficient. The two parameters of greatest importance in the computer simulation are attenuation coefficient and critical fluence. Both depend on the concentration of active drug within the prostate gland. It is necessary to know the nature of the spatial distribution of photosensitizer within the prostate to execute computer modeling of PDT with high precision. We found that the concentration of SnET2 is heterogeneous in nature, and is higher in the proximity of the glandular capsule. It is clear therefore that any future attempts of computerized modeling of this procedure must take into consideration the uneven sequestration of photosensitizer and the consequential asymmetrical necrosis of the prostate.

A novel form of the plasminogen activator inhibitor created by cysteine mutations extends its half-life: relevance to cancer and angiogenesis

Proteolytic activity driven by urokinase (uPA) is commonly recognized as an important factor in metastasis and angiogenesis. The eradication of unwanted uPA activity expressed by cancer cells results in the inhibition of metastasis and angiogenesis. Development of novel and highly selective uPA inhibitors could, therefore, produce new treatments of cancer. The ultimate goal of this work is the identification of novel and selective inhibitors of uPA suitable for this purpose. We have chosen plasminogen activator inhibitor(s) type 1 (PAI-1), which selectively inhibits the urokinase plasminogen activator (uPA). However, PAI-1 is not a stable molecule and converts itself into the latent form with a half-life in the range of t1/2 = 1-2 h. This conversion is associated with a partial insertion of the reactive loop (P4-P10') into the PAI-1 molecule. In such a conformation, P1-P1' and other sites are not accessible for reaction with uPA. To conquer this hurdle, we have produced several PAI-1 mutants by replacing chosen amino acids with cysteine in the hope of creating disulfide bridges, which could make this insertion more difficult. On the basis of the known structure of active PAI-1, we have identified amino acids that can be substituted with a cysteine residue to produce disulfide bridges linking the top and bottom parts of strands A3 and A5 as well as sites within the helix-D region. We created a total of seven cysteine mutants via point mutation (two to six point mutations), generating possible sites for disulfide bridge formation at the top and bottom parts of A3 and A5, within the helix-D region, or by a combination thereof. Desired mutations were introduced by PCR using appropriate primers. The mutant forms of PAI-1 containing the chitin-binding intein tag were then purified using affinity chromatography wherein the intein tag is cleaved, leaving mutant PAI-1 protein. Cys mutations resulted in proteins with extended half-life of PAI-1 from 2 to >700 h depending on the mutant. Novel PAI-1 were fully functional against uPA and showed activity in the in vitro model of angiogenesis, e.g., in the inhibition of sprout formation. Such prolonged serpin activity, which is therapeutically desired in cancer treatment and Cys-mutated PAI-1, could launch a new class of novel anticancer agents.

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.

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.

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.

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.