Morphological effects of photodynamic therapy on rabbit bladder using Photofrin II and Photosan intravesically and intravenously.

Photodynamic therapy (PDT) has proved effective against superficial papillary bladder tumours and focal and diffuse carcinoma in situ. Effective topical administration of the sensitiser would be a welcome improvement. The morphological effects of PDT on the normal bladder were examined in 13 rabbits when 2 photosensitisers (Photofrin II and Photosan III) were applied intravesically (5 mg/kg for 1 h) and compared with intravenous administration (3 or 5 mg/kg). Four animals served as controls without a sensitiser. Intravesical red light (630 nm) from an argon dye laser was used to activate the photosensitiser, using light doses of 12 or 24 J/cm2. The animals were sacrificed either 1 or 5 to 7 days after the laser treatment. Intravenous dosage induced bladder wall oedema/haemorrhage and total necrosis of the epithelium. There was no difference between the effects of the 2 sensitisers. Intravesical application induced superficial epithelial necrosis. The control animals treated with laser light alone showed slight superficial injury to the cell layer.     

Photodynamic therapy of human ocular cancer

Photodynamic therapy (PDT), also known as photoradiation therapy, was employed in five patients with ocular tumors that had been photosensitized to hematoporphyrin derivative (HPD). In each case more conventional treatment had failed to control the tumor, or the patient was considered a poor candidate for surgical intervention because of advanced age or general health. Intravenous administration of 2.5-3.0 mg/kg HPD was followed by PDT 2-4 days later, using a dye laser tuned to a wavelength of 632 nm. Laser light was delivered either by a fiber optic probe maintained at a fixed distance, or via a slit lamp system, for intervals of up to 20 minutes. The levels of energy applied were mainly below 420 Joules/cm2, but for tumors less than 1 mm diameter energy levels were as high as 3000 J/cm2 with a conservative power value as low as 20 mW/cm2. Tumor response to PDT was disappointing. Although substantial superficial tumor necrosis occurred in several cases, it did not extend to the deeper levels of tumor tissue. In each instance surgical intervention became necessary. Deficiencies in the procedure are discussed.     

The morphological changes in rat bladder after photodynamic therapy with 5-aminolaevulinic acid-induced protoporphyrin IX

OBJECTIVE: To assess the optimum light energy needed to induce only superficial bladder wall damage during photodynamic therapy (PDT) as a treatment for bladder cancer. Materials and methods The urinary bladder (with normal epithelium) of 64 female rats was treated with PDT using a continuous-wave argon-ion laser as an energy source and aminolaevulinic acid (ALA)-induced protoporphyrin IX photosensitizer. Four hours after the intravenous administration of ALA (300 mg/kg) the bladders were intravesically exposed to light fluences of 20-80 J/cm2. The control rats received no ALA and were exposed to 20 J/cm2 light. After 1, 3, 7 and 21 days the animals were killed and the morphological changes in bladder wall analysed both macroscopically and using light and scanning electron microscopy. RESULTS: At the dose of ALA given, a fluence of 20-40 J/cm2 caused mainly superficial damage, whereas 80 J/cm2 produced full-thickness injuries to the bladder wall. The maximum effect of PDT occurred after 1 and 3 days of irradiation. After 3 weeks of PDT the histology showed few full-thickness injuries and only in those treated with 80 J/cm2 light. CONCLUSION: These results indicate that PDT can be used to safely induce a selective superficial removal of bladder mucosa with no fibrotic effects on detrusor musculature, when optimum photosensitizing drug and fluences are used. These findings support the use of PDT in the therapy of superficial bladder cancer.     

The effect of photodynamic therapy on rat urinary bladder with orthotopic urothelial carcinoma

OBJECTIVE: To assess the effect of whole-bladder photodynamic therapy (PDT) on a rat model with orthotopic superficial bladder cancer, as PDT is an alternative intravesical therapy for treating superficial bladder cancer, based on an interaction between a photosensitizer and light energy to induce oxygen radicals that destroy tissue by lipid peroxidation. MATERIALS AND METHODS: In all, 76 female Fischer F344 rats were inoculated intravesically with AY-27 tumour cells. After establishing superficial tumour, 24 rats were treated with PDT using aminolaevulinic acid (ALA)-induced protoporphyrin IX as a photosensitizer, and a continuous-wave argon pumped-dye laser (638 nm). At 4 h after intravenous (300 mg/kg) or intravesical (100 mg/mL) administration of ALA the bladders were intravesically exposed to a 40 J/cm(2) light dose; 12 rats received no ALA but were exposed to the same light dose. Before administering ALA, urine cytology samples were taken for analysis. At 3 or 21 days the treated rats were killed and morphological changes in the bladder walls analysed by light microscopy. Forty rats served as controls to examine the presence of tumour. RESULTS: The tumour established in 33 of 40 rats (83%) in the controls, but after PDT with intravesical ALA there was carcinoma in only in one of 12 (P < 0.001, Pearson's chi(2) test). After PDT with intravenous ALA there was carcinoma in five of 11 rats (P = 0.063, Pearson's chi2 test). In the control group of 12 rats receiving only light energy there was carcinoma in three (P = 0.001, Pearson's chi(2) test). Histologically, at 3 days after PDT there was only mild superficial damage in all six rats treated intravesically. Bladder wall destruction reached the muscular layer, with an abscess in one of six rats treated intravenously. After 3 weeks of PDT there was muscular necrosis with perforation and abscess from catheterization two of six rats treated intravesically and in three the bladder wall totally recovered. In the intravenous group the bladder walls were normal or had only mild superficial damage. Cytology of the urine sediment failed to detect half the tumours in the treatment groups. CONCLUSION: These results support the use of PDT with intravesical ALA-induced protoporphyrin X for treating superficial bladder carcinoma. Intravesical was better than intravenous ALA in eradicating bladder carcinoma with PDT.     

A phase-1 study of sequential mitomycin C and 5-aminolaevulinic acid-mediated photodynamic therapy in recurrent superficial bladder carcinoma

OBJECTIVE: To report a phase-1 study of patients with recurrent superficial bladder cancer treated with photodynamic therapy (PDT) using sequential mitomycin C and 5-aminolaevulinic acid (ALA). PATIENTS AND METHODS: Twenty-four patients were treated, the primary endpoint being the safety and tolerability of combined therapy at increasing doses of ALA and light. RESULTS: Mitomycin C instillation was followed by ALA concentrations of 6%, 8% or 10%; there was no effect on toxicity. The light dose, at a wavelength of 635 nm, was increased from zero to 25 J/cm(2), with the upper fluences producing transient symptoms. There were no episodes of skin photosensitivity or systemic toxicity. A total fluence of 25 J/cm(2) represented the upper light dose for the tolerability of this procedure by patients. There were no persistently high urinary symptom scores or reduction in functional bladder capacity up to > or =24 months of follow-up. In this group, cumulative tumour recurrences were none at 4, two at 8, six at 12, nine at 18 and 11 at 24 months after PDT, respectively. CONCLUSION: Sequential mitomycin C and ALA-PDT is a safe and well tolerated treatment, with potential for managing difficult-to-control superficial transitional cell carcinoma and carcinoma in situ of the bladder.     

Enhanced tumor control following sequential treatments of photodynamic therapy (PDT) and localized microwave hyperthermia in vivo

Photodynamic therapy (PDT), or photoradiation therapy (PRT), utilizing hematoporphyrin derivative (HPD) as photosensitizer and an argon-dye laser system as the light source, was used alone and in combination with localized microwave hyperthermia (2450 MHz) to treat axillary tumors of the SMT-F mammary carcinoma in mice. Thirty-minute heat treatments were applied either immediately before or immediately after a standard PDT treatment of 630 nm light at 75 mW/cm2 for 30 min (135 J/cm2) given 24 hr post-7.5 mg/kg HPD, intraperitoneally (i.p.). Tumor control as judged by lack of tumor regrowth 35 days or longer after the combined treatments was compared to that following each treatment when given alone. Little or no enhancement of tumor control was seen when sublethal temperatures of 37.5, 38.5, and 39.5 degrees C were applied for 30 min immediately following the PDT treatment. However, increasing levels of enhancement were seen when heat treatments of 40.5 and 41.5 degrees C or 44.5 degrees C, given for 30 min, were applied immediately before or after the photodynamic treatment.     

The morphological and functional changes in rat bladder following photodynamic therapy with phthalocyanine photosensitization

We have studied photodynamic therapy (PDT) in the rat bladder with a new photosensitizer, aluminium sulfonated phthalocyanine (AlSPc) given intravenously and intravesically. The microscopic distribution of photosensitizer fluorescence in the bladder wall was studied by laser fluorescence microscopy. Prior to PDT the bladder capacity and compliance were assessed by filling cystometry. Intravesical red light (675 nm.) from a copper vapour pumped dye laser was used to activate the photosensitizer using light doses of 20 to 200 J/cm2. Urodynamic and histologic changes were studied at intervals for up to three months. The fluorescence studies showed that AlSPc was eliminated from the deeper muscle layers more quickly than from the superficial layers of the bladder wall so that by 24 hours there was four times as much fluorescence from the mucosa and lamina propria compared to the deeper muscle. Control bladders illuminated with laser light alone showed no effects at these light doses. Animals treated 24 hours after sensitization showed a reduction in bladder capacity of up to 78% (20 J/cm2. light and 1.5 mg./kg.AlSPc). An initial reduction in compliance recovered in two weeks after low doses (0.5 mg./kg.) of AlSPc but was still abnormal at three months after higher doses (1.5 mg./kg.); though there was no long term histologic abnormality seen. Aluminium sulfonated phthalocyanine is a promising photosensitizer for bladder photodynamic therapy and using low doses of the drug it is possible to produce a superficial necrosis without muscle damage across a range of light doses. This heals by epithelial regeneration with no long term functional impairment. Direct absorption of this photosensitizer following intravesical administration seems unreliable.     

Photodynamic therapy: Optimal treatment parameters in murine fibrosarcoma

We have investigated the efficacy of photodynamic therapy (PDT) by using two preparations of haematoporphyrin derivative (HPD) that demonstrated different biological activities against experimental murine fibrosarcoma RIF-1 in C3H/He mice. We have been able to demonstrate a minimum clonogenic survival rate of 0.25% by using the more active HPD at 20 mg/kg with a 40-h retention time and a total laser light dose of 100 J/cm². Further, we noted that clonogenic survival rates of 21.6% and 25.0% respectively could be achieved by using the less active HPD (at 20 mg/kg) with a laser light dose of 150 J/cm², or the more active HPD (at 20 mg/kg) with a laser light dose of 20 J/cm². In both cases necrosis of the surrounding normal tissue was absent. Necrosis of the normal tissue surrounding the tumour was shown to be associated with high laser energy (100 J/cm² and higher) in conjunction with a high dose (20 mg/kg) of the more active HPD. A comparison of survival curves as a function of laser energy for the RIF-1 cells following PDT with the two different preparations of HPD showed a difference in the kinetics of cell death. A curve with a shoulder region and aD _o (mean lethal dose) of 41 J/cm² was obtained when the less active HPD was used, whereas PDT using the more active HPD resulted in a curve with no shoulder and aD _o of 16 J/cm².     

Photodynamic effects of SIM01, a new sensitizer, on experimental brain tumors in rats

BACKGROUND: Glioblastomas are the third most common cause of cancer death in patients between 15 and 35 years old. Literature suggests that PDT could represent a promising treatment, providing that sensitizers could accumulate within the cancer tissues despite the blood-brain barrier. METHODS: Distribution and PDT effect of SIM01, a promising photosensitizer, have been evaluated on orthotopic C6 tumor model in rats by comparison with HPD and m-THPC. Pharmacokinetics had been analyzed with fluorescence and ROS. Photodynamic treatment was done using a 630-nm light with an energy density of 100 J cm(-2) for HPD and a 652-nm light with an energy density of 20 J cm(-2) for m-THPC and SIM01. RESULTS: The correlation between fluorescence and ROS dosimetry was found to be excellent. An optimal concentration was found after 12 hours for SIM01 (4 mg/kg), 24 hours for HPD (10 mg/kg), and 48 hours for m-THPC (4 mg/kg). The best normal tissue/cancer ratio of concentration had been found after 12 hours for SIM01 and 48 hours for HPD and m-THPC. Pathological examinations after PDT showed that the criteria for histology of glioblastic origin were absent in SIM01-treated rats 12 hours after injection but were present in 50% of rats treated 24 hours after injection and in all after a 48-hour delay. Mean survival of rats treated 12 or 24 hours after SIM01 injection was significantly improved compared with controls, HPD-, or m-THPC-treated groups. Survival of rats treated 12 or 24 hours after SIM01 injection reached 20 days but decreased for longer delays. On the contrary, survival reached 18 days at the maximum for rats treated 48 hours after m-THPC or HPD injection. CONCLUSIONS: Our results confirm that PDT is a promising treatment for glioblastomas. SIM01 efficacy is as efficient as m-THPC but with much more favorable pharmacokinetics.     

Photodynamic therapy for head and neck cancer xenografts in athymic mice

This study examines efficacy and optimal treatment variables of photodynamic therapy (PDT) for human head and neck squamous cancer (HNSC) xenografts in athymic mice. Two and four days after injection of hematoporphyrin derivative (HPD), tumors were illuminated with red light from an argon-dye laser. Sixty-three tumors were treated. With HPD dose and light intensity constant at 7.5 mg/kg and 100 mW/cm2, respectively, the extent of tumor necrosis was strongly dependent on duration of light exposure. There was no substantial difference in results for 30- and 60-minute treatment durations between animals injected with HPD 2 and 4 days before treatment. After 30 minutes treatment time, responses were seen in 8 of 10 mice (2 days post-HPD) and 11 of 12 mice (4 days post-HPD). After 60 minutes treatment time, toxicity was high. We conclude that, in this model, PDT is effective in selective killing of HNSC. For future comparison studies in this model, if the indicated HPD dose and light intensity are used we recommend a 2-day delay after HPD injection and a light exposure duration of 30 minutes.     

Photodynamic therapy for superficial bladder cancer under local anaesthetic

OBJECTIVES: To evaluate the use of local anaesthesia (LA) in 5-aminolaevulinic acid (ALA) photodynamic therapy (PDT) for superficial transitional cell carcinoma (TCC) of the bladder, and to provide further toxicity and tolerability data on this new method within the context of a phase 1 trial. PATIENTS AND METHODS: ALA PDT was administered to 19 patients with recurrent superficial TCC (stage Ta/carcinoma in situ, grades 1-3) using escalating doses of ALA (3-6%) and 633 nm laser light (25-50 J/cm2) under various LA (lignocaine) protocols. Pain was assessed using a linear analogue scale from 0 to 10. The endpoints of tolerability and toxicity were assessed for the different LA, light and ALA doses, with lignocaine levels. RESULTS: ALA PDT is painful and requires some form of anaesthesia. The discomfort was immediate, associated with bladder spasm, and was a function of the ALA concentration rather than the total light dose given. Simple passive diffusion (PD) of 2% lignocaine instilled for 40 min before PDT gave adequate anaesthesia with 3% ALA (n=8; median pain score 1, range 0-2). With 6% ALA the pain was dramatically increased using PD (n=6; median pain score 8, range 5-10) and therefore the more potent LA technique of electromotive drug administration (EMDA) of 2% lignocaine was used, with excellent results (n=3; median pain score 1, range 0-2). All patients had transient bladder irritability that typically lasted 9-12 days, with no subjective/objective change in long-term bladder function. No other toxicity was reported. Serum lignocaine levels were minimal. CONCLUSION: Bladder ALA PDT is both safe and feasible under LA. At a dose of 3% ALA, the procedure was well-tolerated using PD of lignocaine. At higher doses (6% ALA) more effective anaesthesia is required and this can be obtained satisfactorily with EMDA of lignocaine. With refinement, ALA PDT may be feasible as an outpatient treatment for superficial bladder TCC.     

Experimental photodynamic treatment of canine bladder

In urology, important limiting factors in the application of hematoporphyrin derivative and photodynamic therapy appear to be the problems of standardization of dosimetry and the technique of transurethral photoradiation. Experimental photodynamic therapy on canine bladder with normal and altered epithelium was performed using an argon laser as an energy source. A 630 nanometer wavelength of light was delivered through a quartz-optical fiber with either a regular flat end for focal illumination or a bulb-type end which produced an isotropic light pattern. It was demonstrated that normal canine bladder was resistant to photodynamic therapy and that the bulb tip produced whole bladder illumination. With a moderate light dose of 18 to 30 Joules/cm.2 the effect following whole bladder illumination on the bladder was generalized and superficial. This approach appears to be ideal for treating superficial transitional cell carcinoma of the bladder. Additional work is needed in selecting appropriate energy doses.     

Photodynamic therapy for refractory superficial bladder cancer: long-term clinical outcomes of single treatment using intravesical diffusion medium

BACKGROUND: Diffuse superficial transitional-cell carcinoma (TCC) refractory to standard therapies poses a clinical dilemma. Photodynamic therapy (PDT), which uses an interaction between absorbed light and a retained photosensitizing agent to destroy tissue, has been used to treat diffuse superficial bladder TCC, although there are few reports of long-term outcomes. PATIENTS AND METHODS: A series of 34 patients, 29 with TCC carcinoma in situ (CIS) and 5 with multiple small papillary stage T(a) or T(1) lesions, received porfimer sodium (P) 48 hours before whole-bladder PDT with 630-nm laser light. A 0.02% soybean emulsion diffusion medium was instilled into the bladder, and the laser optical fiber was positioned under triplanar sonography prior to PDT. The mean follow-up was 52 months. RESULTS: At 3 months, a complete response (CR) in 14 (44%) of the 32 evaluable patients, a partial response (PR) in 4 (12%), and no response (NR) in 14 (44%). Four of the five patients with extensive papillary lesions did not respond. The NR rate for patients with CIS with or without resected papillary lesions was 37%. The mean time to recurrence in the CR group was 9.8 months, and five members of this group (36%) underwent cystectomy (mean time 20 months) for persistent/progressive disease (N = 3) or bladder contracture (N = 2). In the NR group, 6 (43%) underwent cystectomy (mean time 14 months) for persistent/progressive disease. Metastatic bladder cancer was the cause of death in only 4 of the 12 patients who have died. Of the remaining 22 patients, 15 are still alive and have an intact bladder, nine with no disease and six with only superficial disease. CONCLUSION: This is the first report of long-term results following whole-bladder PDT using diffusion medium for isotropic light distribution. More than half of the patients with TCC refractory to traditional intravesical therapy received benefit from a single PDT session. Patients with extensive flat papillary lesions do not appear to respond well. Patients who achieve a CR have less likelihood of and longer time interval before needing cystectomy for progressive disease than NR patients. Our PDT protocol is associated with minimal morbidity in these high-risk patients.     

PSD-007介导的光动力疗法治疗小鼠骨肉瘤的实验研究

目的 观察光敏剂PSD-007对小鼠骨肉瘤细胞LM-8的体外及体内光动力效应.方法 PSD-007与LM-8细胞共同孵育后以激光照射,应用MTT法测定光密度(OD540)值,计算抑制率.40只C3H小鼠接种LM-8细胞,皮下瘤块直径7～8 mm时随机分为:(1)对照组,空白对照、生理盐水加光照、注射PSD-007不光照;(2)光动力治疗组,分别注射5mg/kg、10mg/kg PSD-007,6 h后以激光照射.1周后测量瘤体大小、重量,计算抑瘤率并行病理学检查.C3H小鼠30只建立肿瘤模型,肿瘤直径达10～12mm时,分别行肿瘤边缘切除无光动力治疗(对照组)、边缘切除后240 J/cm2光动力治疗及边缘切除后360 J/cm2光动力治疗.4周后比较肿瘤复发率.结果 体外只光照或只注射PSD-007对LM-8细胞均无杀伤作应.PSD-007浓度越高、激光照射强度越大,LM-8细胞OD540值越小.PSD-007浓度>4μg/ml,光照强度>6 J/cm2时,抑制率>50%.光镜下细胞形态呈坏死或凋亡样改变.体内实验显示光动力治疗组的肿瘤体积及瘤重均减小,肿瘤边缘切除高强度激光照射组的复发率较对照组低.结论 PSD-007对LM-8细胞有明确的光动力抑制效应,其作用大小取决于其浓度和激光照射强度.光动力疗法可以降低肿瘤边缘切除后的复发率.

Abstract：

Objective To evaluate the PSD-007-mediated photodynamic effect on mouse osteosarcoma cell line LM-8, both in vitro and in vivo. Methods LM-8 cells were incubated with different concentrations of PSD-007 for 4 hours and then followed different laser irradiations. After photodynamic therapy (PDT), cell viability was measured using MTT assay and the optical density in each experiment was measured at 450 nm with a micro plate reader. The inhibition rate of cell growth was calculated. Four-week-old female C3H mice were used for implantation of LM-8 cells. When the diameter of tumor reached up to 7-8 mm, the mice were randomly divided into following groups: 1) control group, including untreated control, saline with laser irradiation, PSD-007 without laser irradiation; 2) PDT group, PSD-007 (5 and 10 mg/kg) was injected intravenously into the mice, and the tumor site was irradiated with laser light 6 hours after injection. Seven days after PDT, the size and weight of the tumors were measured. The inhibition rate of tumor was calculated, and all tumor specimens were taken for pathologic examination. After the diameter of tumor was 10-12 mm, the tumors were performed a marginal resection and subsequently followed 3 different treatments: without PDT (control), PDT with 240 J/cm2 or 360 J/cm2 laser irradiation. After 4 weeks treatment, the tumor recurrence rates were analyzed. Results MTT assay revealed that the cytotoxic effect of PDT on the LM-8 cells was positively correlated with the concentration of PSD-007 and the level of laser irradiation. When the concentration exceeded 4μg/ml, and the energy exceeded 6 J/cm2, the inhibition ratio was over 50%. No anti-tumor effect was observed in the cells treated with only laser irradiation or PSD-007 injection. Compared with the control group, the size and weight of the tumors were obviously decreased after PDT. PDT performed after marginal resection of the tumor reduced the rate of local recurrence. Conclusion PDT with PSD-007 showed cytotoxic effect on the LM-8 cells, and which performed after marginal resection of the tumor reduced the rate of local recurrence.     

Photodynamic therapy of head and neck basal cell carcinoma according to different clinicopathologic features

BACKGROUND AND OBJECTIVES: We aimed to treat different pathologic types of basal cell carcinomas (BCCs) using photodynamic therapy (PDT). STUDY DESIGN/MATERIALS AND METHODS: Thirty lesions in six patients underwent PDT. The photosensitizer used was Photoheme, a hematoporphyrin derivative IX. It was injected intravenously at the dose of 2-3.25 mg/kg. After 24 hours, the lesions were illuminated by laser light (lambda = 632 nm, light exposure dose = 100-200 J/cm2). Lesions were evaluated pre and post-operatively and at follow-up sessions (of up to 6 months). RESULTS: After a single session of PDT, the average response rate in different histopathologic kinds of basal cell carcinoma (e.g., ulcerative, superficial, nodular, and pigmented forms) were 100%, 62%, 90%, and 14%, respectively. In patients who responded completely, the cosmetic results were excellent and there were no recurrence at 6th month of follow-up. CONCLUSION: Although PDT seems to be an effective treatment modality for superficial, ulcerative, and nodular BCCs, it is not recommended for pigmented lesions.     

Photodynamic activity of lutetium-texaphyrin in a mouse tumor system.

BACKGROUND AND OBJECTIVE: New photosensitizers proposed for photodynamic therapy (PDT) treatment of tumors need to be evaluated in animal models to determine the parameters needed for treatment. They also need to be compared with existing photosensitizers for efficacy. We examined the PDT response to lutetium-texaphyrin (PCI-0123) in a mouse mammary adenocarcinoma model and compared it with the PDT response seen when using Photofrin. STUDY DESIGN/MATERIALS AND METHODS: DBA/2 mice with SMT-F tumors were used to explore PCI-0123 toxicity, laser light dose, and drug dose effects on PDT response and to determine the most effective time for light application. The PDT response of PCI-0123-treated tumors was compared with that of Photofrin-treated tumors. RESULTS: Treatment of tumors with 150 J/cm2 of 740 nm laser light 5-6 hr after PCI-0123 administration (40 mg/kg) resulted in a 100% response rate and a 55% cure rate. Tumors treated with 150 J/cm2 of 630 nm laser light 24 hr after Photofrin administration (10 mg/kg) resulted in a 67% response rate and a 16% cure rate. CONCLUSION: PCI-0123 was found to be a more effective photosensitizer than Photofrin.     

Photoradiation therapy of bladder tumors

Photoradiation therapy, in which hematoporphyrin derivative is activated by an argon-dye laser, was performed on 46 superficial bladder tumors in 9 patients. A fluorospectrophotometric study of biopsies from these tumors and normal mucosa revealed preferential hematoporphyrin derivative localization in malignant tissues. The tumor response was confirmed ultrasonographically in 36 stages Ta to Tl tumors. Treatment with 100 to 250 J./cm.2 obtained complete remission in 5 of 6 patients with tumors 1 cm. in size or less. For those with tumors up to 2 cm. in size the light intensity should be 300 mw./cm.2 for 5 to 10 minutes or more and the accumulated energy intensity of light dose should be 100 J./cm.2 or more. No patient with tumors more than 2 cm. in size had a complete remission.     

Hematoporphyrin derivative photoradiation therapy of the rat 9L gliosarcoma brain tumor model

The distribution of hematoporphyrin derivative (HPD) in the rat 9L gliosarcoma intracerebral brain tumor model at 4, 24, 48, and 72 hours after intravenous administration was evaluated using a digital video fluorescence microscopy technique. Maximum tissue fluorescence in the normal brain was observed at 4 hours, whereas maximum fluorescence in the tumor regions occurred at 24 hours. Although the fluorescence counts suggested that there was significant uptake of HPD within the tumors when compared to normal brain, only 33% to 44% of each of the eight tumors surveyed showed fluorescence. In response to a laser light dose (633 nm) of 30 J/cm2, six rats that had been sensitized with HPD had a patchy coagulation necrosis involving up to 70% of the total tumor volume. In contrast, four rats given HPD only or exposed to laser only had no areas of necrosis, as observed on histological examination. In a group of 30 rats, no prolongation of survival was observed in response to photoradiation therapy.     

经尿道绿激光汽化和经尿道电切治疗经尿道电切治疗浅表性膀胱肿瘤的疗效比较

目的：比较经尿道绿激光汽化与经尿道电切治疗表浅性膀胱肿瘤的疗效及安全性。方法：对70例经病理活检证实的表浅性膀胱肿瘤患者,采用随机的方法,分别运用经尿道绿激光汽化和经尿道电切两种方法进行治疗。对两组手术时间、术中出血量、膀胱穿孔例数、保留尿管时间及肿瘤复发等指标进行比较。结果：两组平均手术时间差异无统计学意义（P〉0．05）,绿激光汽化组术中出血量、肿瘤复发率低于电切组（P〈0.01）;且绿激光汽化术后无需膀胱冲洗及无膀胱穿孔之忧。结论：经尿道绿激光汽化术治疗浅表性膀胱肿瘤具有安全性高、恢复快、复发率低等优势,尤其适用于老年、心肺等功能差的患者。     

Effect of hematoporphyrin derivative photoradiation therapy on survival in the rat 9L gliosarcoma brain-tumor model

Intracerebral tumors were produced in 99 rats by stereotaxic implantation of 9L gliosarcoma brain-tumor cells. Hematoporphyrin derivative (HPD), 10 or 20 mg/kg, was administered as an intravenous bolus 24 or 48 hours before irradiation of the tumor region with light from an argon pumped-dye laser (632 nm). Laser light, at a dose of 30, 60, or 200 joules/sq cm, was delivered through a craniectomy 10 or 13 days after tumor implantation. Survival times were significantly prolonged in rats exposed to laser light at a dose of 200 joules/sq cm 24 hours after administration of HPD, 20 mg/kg.