A Comparison between Argon-dye and Excimer-dye Laser for Photodynamic Effect in Transplanted Mouse Tumor

Photodynamic therapy (PDT) utilizing a hematoporphyrin derivative (HpD) as a sensitizer has become a viable option for the local treatment of neoplastic disease. The argon-dye laser system is commonly used as a light source in this treatment modality. The excimer-dye laser, on the other hand, delivers high-energy red light in a pulsatile fashion. In this investigation, we treated BALB/c mice bearing mouse kidney sarcoma cell tumors with PDT using HpD at the dose of 5 mg/kg body weight as a photosensitizer and either a standard argon-dye laser or the pulsatile excimer-dye laser as the light source. At equal light energy doses (50 J/cm²), necrotic changes at depths averaging 4 mm from the tumor surface were obtained with the argon-dye laser (200 mW power output) while tumor necrosis at depths exceeding 15 mm from the tumor surface was obtained using the excimer-dye laser (6 mJ/pulse, 5 Hz). To determine the best conditions for photoirradiation with the excimer-dye laser, tumor-bearing mice were treated with different total light doses (10, 30 and 50 J/cm²), dose rates (1, 3 and 6 mJ/cm²), and frequencies (5,15 and 50 Hz) of light exposure. Our results indicate that the optimal effects obtained with the excimer-dye laser are related to the total light dose used and the dose rate, but not to the frequency of light exposure.     

Photodynamic therapy of human malignant melanoma xenografts in athymic nude mice

While photodynamic therapy (PDT) for cutaneous malignancies including dermal recurrences of breast cancer and basal cell carcinomas has shown great promise, PDT of malignant melanoma has remained incompletely understood. A comparison study of the effects of PDT on human xenograft amelanotic and melanotic malignant melanoma in the athymic nude mouse model was performed. Twenty-four hours after ip administration of Photofrin II, the responses to total laser light doses of 25-300 J/cm2 were evaluated by histologic examination. Animals were also sacrificed 24 hours after administration of Photofrin II without light, and their uptake and localization of hematoporphyrin derivative (HpD) for each tumor were measured and compared. The results indicate that human xenograft melanotic melanoma, despite the fact that it contains more HpD than does amelanotic melanoma, is far less responsive to PDT. This result appears to be due to the competing chromophore melanin, which may inhibit the photochemical reaction at several key points.     

Photodynamic therapy of photofrin II and excimer dye laser on experimental tumors

Photodynamic therapy (PDT) by combination of photofrin II and excimer dye laser was evaluated for its usefulness in experimental tumors. High antitumor effects of PDT on sarcoma 180 solid type were obtained when PDT was performed with laser irradiation at an energy of 50 or 100 J/cm² (40 or 80 Hz, 4 mJ/pulse) 48 h after i.v. administration of photofrin II at a dose of 25 mg/kg. Under the same conditions, the antitumor effects of PDT on murine Lewis lung carcinoma, human fibrosarcoma HT-1080 and human bladder transitional cell carcinoma KK-47 were also observed. These results suggest that clinical application of PDT with photofrin II and excimer dye laser might be useful.     

Evaluation of porphyrin C analogues for photodynamic therapy of cerebral glioma.

A series of monomeric porphyrins (2-8) based on porphyrin C (1) have been tested as sensitisers for photodynamic therapy (PDT) of cerebral glioma using the in vitro/in vivo C6 intracerebral animal tumour model. The in vivo screening, consisting of cytotoxicity, phototoxicity (red light) and subcellular localisation studies, revealed two sensitisers (porphyrin 7, molecular weight 863 Da and porphyrin 8, molecular weight 889 Da), which had greater photoactivity than porphyrin C and similar photoactivity to haematoporphyrin derivative (HpD) although at a 5-fold higher dose than HpD. Both sensitisers showed intracellular localisation to discrete organelle sites and exhibited considerably less ''dark'' cytotoxicity than HpD. The kinetics of uptake of porphyrins 7 and 8 was studied in the mouse C6 glioma model as well as in biopsy samples from normal brain, liver, spleen and blood. Maximal drug uptake levels in tumour occurred 9 and 6 h after intraperitoneal injection for 7 and 8 respectively, at which time the tumour to normal brain ratios were 15:1 and 13:1 respectively. The effect of PDT using porphyrin 7 activated by the gold metal vapour laser tuned to 627.8 nm was studied in Wistar rats bearing intracerebral C6 glioma. At a drug dose of 10 mg porphyrin 7 kg-1 body weight and laser doses of up to 400 J cm-2 light, selective tumour kill with sparing of normal brain was achieved, with a maximal depth of tumour kill of 1.77+/-0.40. mm. Irradiation following a higher drug dose of 75 mg porphyrin 7 kg-1 body weight resulted in a greater depth of tumour kill, but also significantly increased the likelihood and extent of necrosis in normal brain.     

Whole bladder wall photodynamic therapy of transitional cell carcinoma rat bladder tumors using intravesically administered hypericin

Whole-bladder wall photodynamic therapy (PDT) is a promising treatment for carcinoma in situ (CIS) and diffuse premalignant changes of the bladder. After the results of our clinical studies showing that intravesical hypericin selectively accumulates in superficial bladder tumors, we investigated the hypericin-PDT efficacy in an AY-27 orthotopic transitional cell carcinoma rat bladder tumor model. After the instillation of hypericin (30 microM, 2 hr) in the bladder, tumors were irradiated (25-50 mW/cm 6-48 J/cm(2)) using 595 nm laser light. Data demonstrate that light doses of 12-48 J/cm(2) resulted in selective PDT-induced urothelial tumor damage without damaging detrusor musculature. Histological assessment of bladder sections 2 days after PDT showed tumor destruction, with tumor cells shrinking and detaching from the bladder wall. There were tumor regrowth 1-3 weeks after treatment. The in vivo/in vitro clonogenic assay results revealed up to 98% of tumor cell kill by hypericin PDT. In conclusion, hypericin PDT can be used to safely induce a selective urothelial tumor damage without damaging detrusor musculature, when optimum hypericin concentration and light fluences are used. A small percentage (2-5%) of tumor cells that survive the photodynamic treatment resulting in tumor regrowth after a prolonged period of time is likely due to oxygen depletion during light irradiation.     

Photodynamic cell killing effects and acute skin photosensitivity of aluminum-chloro-tetrasulfonated phthalocyanine and hematoporphyrin derivative

Aluminum-chloro-tetrasulfonated phthalocyanine (PC) showing an absorption peak at 678 nm was compared to hematoporphyrin derivative (HpD), a photosensitizer commonly used in the photodynamic therapy (PDT) of cancers. In vitro studies: KK-47 cells were exposed to long-wavelength ultraviolet (UVA) or red light (greater than 600 nm, greater than 640 nm and greater than 660 nm) after drug sensitization. With UVA irradiation, a higher photodynamic cell killing effect was observed in the cells treated with HpD than with PC. However, with red light irradiation (both greater than 640 nm and greater than 660 nm) PC resulted in greater cell damage. PC was less toxic to KK-47 cells in the dark. In vivo studies: Using a gold vapor laser (GVL: 627.8 nm, 200 mW/cm2, 200 J/cm2), the photodynamic tumor response was determined in C3H/He mice bearing transplantable squamous cell carcinoma. No significant difference was observed in the tumor volume between the PC and HpD groups, except that the PC group (10.0 mg/kg body weight) showed a significantly higher remission rate (3/6) than the control group (0/10, P less than 0.05). Skin photosensitivity test: Skin photosensitivity was estimated by measuring changes in back skin thickness due to photosensitization. With UVA irradiation, a stronger skin reaction was observed in the HpD group, while with visible light irradiation there was no significant difference between the HpD and PC groups. Based on the superior cell killing effect with red light, reduced toxicity to the cells in the dark and mild skin reaction with UVA, PC may be a more promising photosensitizer for PDT.     

Phthalocyanine: a new photosensitizer in photodynamic therapy

Photodynamic therapy (PDT) with hematoporphyrin derivative (HpD) combined with laser irradiation has been introduced as a new promising clinical method for the treatment of various malignancies. Recently, sulphonated aluminum chloro phthalocyanine (A1PC) has attracted a great deal of attention as a new photosensitizer. Tissue concentrations and photodynamic effects of A1PC and HpD, that has been using clinically in PDT, were determined in nude mice transplanted bladder tumors. According to the tissue distribution of A1PC and HpD at various times after administration, the ratios of tumoral concentration to muscular concentration of A1PC were higher than those of HpD, and skin concentration of A1PC at 24 to 168 hrs. after administration was lower than that of HpD. These results suggest that more A1PC localizes in malignant tumor than HpD, and there is a possibility of reducing skin photosensitivity with A1PC as compared with HpD. The regression of tumor volume after PDT was higher with A1PC and laser light at 670 nm than with HpD and laser light at 630 nm.     

The significance of the nature of the photosensitizer for photodynamic therapy: quantitative and biological studies in the colon

Photodynamic therapy (PDT) depends on the interaction of light with an administered photosensitiser to produce a local cytotoxic effect. The most widely used photosensitiser is haematoporphyrin derivative (HpD), but newer photosensitisers such as aluminium sulphonated phthalocyanine (A1SPc) are promising. HpD and A1SPc have been compared as photosensitisers for colonic PDT in the rat. Quantitative analysis showed that following injection of a standard photosensitiser dose, A1SPc produced more damage than HpD with increasing energy (fluence). Alteration of the injected dose of photosensitiser did not produce a clear difference. There was a loss of reciprocity for photosensitiser/light combinations at low injected dose (0.5 mg kg-1), both HpD and A1SPc producing no damage. Similarly at high photosensitiser dosage (25 mg kg-1) there was no quantitative difference between A1SPc and HpD. Photosensitiser photodegradation at low photosensitiser doses, and light attenuation by high tissue concentrations of A1SPc account for these findings. PDT with either agent produced the same histological damage and full thickness necrosis produced no mechanical weakening of the colon measured by the bursting pressure. The submucosal collagen was preserved and healing was by regeneration.     

Minimally-invasive debulking of ovarian cancer in the rat pelvis by means of photodynamic therapy using the pegylated photosensitizer PEG-m-THPC

Interstitial photodynamic therapy (PDT) using the pegylated photosensitizer PEG-m-THPC was evaluated as a minimally-invasive procedure to selectively debulk unrespectable pelvic ovarian cancer (NuTu-19) in immunocompetent rats. To assess tumour selectivity, PEG-m-THPC at dosages of 0.3, 3.0 and 30 mg kg(-1) body weight was administered intravenously to 30 rats 4 weeks following tumour induction. Eight days later laser light at 652 nm and optical doses ranging from 100 to 900 J cm(-1) diffuser-length was delivered by an interstitial cylindrical diffusing fibre inserted blindly into the pelvis. Three days following light application, the volume of necrosis was measured and the damage to pelvic organs was assessed histologically on cross sections. For analysis of survival, 20 tumour-bearing rats received PDT using drug doses of 3 or 9 mg kg(-1) body weight and an optical dose of 900 J cm(-1) diffuser-length, whereas ten untreated tumour-bearing rats served as controls. The histological assessment of PDT induced necrosis showed a non-linear dose-response for both the photosensitizer dose and the optical dose. The lowest drug dose activated with the highest optical dose did not induce more necrosis than seen in tumour-bearing control animals. The same optical dose induced necrosis of 17 mm in diameter using 30 mg kg(-1) and 11 mm using 3 mg kg(-1) photosensitizer. The optical threshold for induction of significant necrosis was between 100 and 300 J cm(-1) diffuser-length for 30 mg kg(-1) and between 300 and 500 J cm(-1) for 3 mg kg(-1) PEG-m-THPC. Significant damage to normal pelvic organs was only seen if 30 mg kg(-1) photosensitizer was activated with optical doses of 700 J cm(-1) or more. In the survival study, all treated animals survived PDT for at least 2 weeks and the intestinal and urinary tract remained functional. No clinical signs of blood vessel or nerve injury were observed. Mean overall survival of untreated tumour-bearing rats was 25.0 +/- 4.5 days compared to 38.4 +/- 3.8 days and 40.0 +/- 3.6 days for rats treated with 3 mg kg(-1) or 9 mg kg(-1) PEG-m-THPC mediated PDT respectively (P < 0.05). We conclude that PEG-m-THPC mediated PDT has a favourable therapeutic window and that this minimally-invasive procedure can reduce pelvic cancer bulks effectively and selectively.     

Photodynamic therapy of locoregional breast cancer recurrences using a chlorin-type photosensitizer

Chest wall recurrences are a frequent problem in patients treated by mastectomy for breast cancer. Surgery and ionizing radiation are established treatment modalities in these cases. Photodynamic therapy (PDT) provides an alternative treatment modality using a photosensitizer and laser light to induce selective tumor necrosis. PDT was performed as compassionate use in 7 patients aged 57.6 years (+/-12.6 SD). A total of 89 metastatic skin nodes were treated in 11 PDT sessions. As photosensitizer meta-tetra(hydroxyphenyl)chlorin (m-THPC) was applied intravenously. Patients (n = 3) photosensitized with a drug dose of 0.10 mg/kg bodyweight were irradiated 48 hr after drug application at a lightdose of 5 J/cm(2). Patients (n = 4) were illuminated by an optical dose of 10 J/cm(2) 96 hr after photosensitization with 0.15 mg/kg. Laser light at a wavelength of 652 nm was generated by a diode laser and applied by a front lens light diffuser using a fluence rate of 20--25 mW/cm(2). PDT using m-THPC resulted in complete response in all patients. Response to treatment did not differ when using the 2 different drugdose protocols. Healing time depended mainly on the size of the illumination field but not on the lightdose. Pain score usually raised 1 day after PDT and lasted at higher levels for about 10 days. Healing time usually ranged between 8--10 weeks. Photodynamic technique offers a minimal-invasive, outpatient treatment modality for recurrent breast cancer on the chest wall with few side effects, high patient's satisfaction and with possible repetitive application.     

Novel After-loading Interstitial Photodynamic Therapy of Canine Transmissible Sarcoma with Photofrin II and Excimer Dye Laser

Novel after-loading interstitial photodynamic therapy was performed in a canine transmissible sarcoma (CTS) model, utilizing photofrin II and an excimer dye laser. First, photofrin II was injected intravenously at a dose of 5 mg/kg, then 48 h later, laser-proof plastic tubing was inserted into the CTS, followed by photoradiation of the tumor from the inside. The mean diameter of tumor necrosis rapidly increased in parallel with increase in total irradiation energy below 240 J/cm; the mean diameter of tumor necrosis was 20.7 mm at an energy of 120 J/cm, and 24.5 mm at 240 J/cm. Beyond 240 J/cm, the diameter gradually increased to 26 mm at 960 J/cm. As a side effect, cutaneous tissue showed a deep open ulcer at 240 J/cm, a shallow open ulcer at 180 J/cm, and a scar healing at 120 J/cm. The thermal effect of laser light is considered negligible below 480 J/cm.     

STUDY ON THE ULTRASTRUCTURE OF SINGLE HeLa CELL TREATED WITH HpD PLUS LASER MICROIRRADIATION

A method is described which permits transmission electron microscope of single cells treated with HpD plus laser microirradiation. The preselected single cell that was irradiated by laser under light microscope and followed fixation, embedded and sectioning is examined under electron microscope. The results demonstrated that at the light dose of 1.88 ml/μm2 not only the irradiated nucleolus appeared transparent region, but the other parts such as non-irradiated mitochondria in cytoplasm can also be damaged. When partial cytoplasm is irradiated with the light dose of 4.50 ml/μm2, the damages appear in all cytoplasm, but there is little change in the nucleus. The experimental results also demonstrate that cytoplasm is more sensitive than nucleus. It is the mitochondria in cytoplasm that are very sensitive to HpD plus laser.     

Experimental photodynamic therapy with a copper metal vapor laser in colorectal cancer.

In an attempt to define the best conditions for an adjunctive treatment of residual colonic microtumors by photodynamic therapy (PDT), an experimental model has been defined. S.c. HT29 colonic-cancer-cell tumors grown in nude mice were used and, 48 hr after i.p. administration of 30 mg/kg Photofrin (PH), laser illumination was performed with 75 or 150 Joules/cm2. The efficiencies of 2 lasers, the classically used rhodamine laser (RL) and a copper metal vapor laser (CMVL), were compared. The effects of PDT were assessed by histological and immunocytochemical (detection of a digestive enzyme, dipeptidyl-peptidase IV, as a marker of cell viability) follow-up and by the growth curve of the tumors after illumination. We conclude that, although the depth of necrosis resulting from PDT was nearly 3 mm at 75 J/cm2 and nearly 4-5 mm at 150 J/cm2 with both lasers, complete necrosis was obtained only with the CMVL at 150 J/cm2 (in 50% of the tumors). Under the other conditions, a layer of unaffected cells persisted at the pole opposite to laser illumination, resulting in growth curves lower than but parallel to those of the controls. Analysis of drug concentrations in the tumors and various organs, 48 hr after injection, i.e., at the time of laser illumination, revealed the presence of 21 micrograms/g dry weight PH in the tumors. The tumor vs. host-organ ratios were equal to or higher than 1 for the small bowel, colon, stomach, lung, skin and muscle. In contrast, the ratios were below 1 for the spleen, pancreas, kidney and liver.     

The effect of hyperthermia on murine leukaemia cells in combination with photodynamic therapy

Mouse leukaemia L1210 cells were subjected to hyperthermia (43.0 +/- 0.05 degrees C, water bath) and photodynamic therapy (50 micrograms/ml haematoporphyrin derivative (HpD), 630 +/- 5 nm at 0.1 mW/cm2) for varying lengths of treatment time in different sequences. Dose-response curves showed that the two modalities interact to make the combination more cytotoxic than the sum of the separate individual treatments, and that a determining factor is the intracellular concentration of HpD of tumour cells during hyperthermia. High cytotoxic (synergistic) effects of photodynamic therapy (PDT) were obtained when PDT was performed after hyperthermia following HpD administration. However, only additive cytotoxic effects were found, when hyperthermia was performed after HpD administration and PDT. These cytotoxic data were supported by DNA damage (the increase in single-stranded DNA) as revealed by flow cytometry in cells stained with acridine orange (AO). These in vitro experiments suggest that clinical applications of PDT after hyperthermia with HpD injection might be useful.     

Photodynamic therapy with mono-L-aspartyl chlorin e6 can cause necrosis of squamous cell carcinoma of tongue: experimental study on an animal model of nude mouse

Mono-L-aspartyl chlorin e6 (NPe6) is an effective photosensitizer with a major absorption band at 664 nm. NPe6 is potentially exploitable for photodynamic therapy (PDT) and does not cause the side effect of prolonged normal skin photosensitization. However, there are no clinical and experimental reports of its use in oral cancer till now. In the present study, we examined the effectiveness of NPe6-induced PDT with a diode laser for treatment of tongue cancer in the nude mouse. Six nude mice with experimental tongue cancer (HSC-3) were given 10 mg/kg NPe6 intravenously. Two hours later PDT was performed using a laser diode at a light dose of 100 J/cm2 and wavelength of 664 nm. Histological changes in the tumors were examined 42-72 h after PDT. Almost all of the tumors developed necrosis, while viable-like neoplastic cells remained mainly in the peripheral region of the tumor in some cases. The mean depth of necrosis below the surface was 2.1 mm. The mean tumor thickness below the surface was 2.3 mm. Tumor thickness coincided with the depth of necrosis. NPe6-induced PDT exhibited tumor selectivity and can effectively cause necrosis of tongue cancers. This therapy could be suggested for treatment of other superficial oral cancer.     

华卟啉钠介导的光动力疗法在体外和体内对肿瘤生长的抑制作用

目的： 观察华卟啉钠 (sinoporphyrin sodium,DVDMS-2)介导的光动力疗法 (DVDMS-2-PDT)在体内外对肿瘤生长的抑制作用及其强度。方法：用噻唑蓝(MTT)法检测DVDMS-2在体外对4种肿瘤细胞 (人肝癌细胞HepG2、人肺癌细胞H460、人胃癌细胞BGC823和人肾癌细胞Ketr-3)的生长抑制作用。采用小鼠肉瘤S180移植性肿瘤模型,按2 mg/kg单次尾静脉注射给予DVDMS-2,给药24 h后进行光动力治疗,分别设低、中、高剂量照射组 (分别为38、76、152 J/cm2),另设生理盐水阴性对照组和阳性对照组 (给予10 mg/kg Photofrin,按76 J/cm2进行光照射),实验结束后,称瘤质量,计算各组肿瘤生长抑制率。采用裸鼠H460细胞荷瘤动物模型,设DVDMS-2低、中、高剂量组 (分别为0.5、1.0、2.0 mg/kg),另设生理盐水阴性对照组和阳性对照组 (给予10 mg/kg Photofrin),激光照射条件为76 J/cm2 ,试验结束后,计算各组肿瘤质量、肿瘤体积、相对肿瘤增殖率T/C (%)等指标。利用SPSS 13.0对数据进行统计分析。结果：DVDMS-2对HepG2、H460、BGC823和Ketr-3细胞均有明显的生长抑制作用,MTT法测定其IC50值为0.207～0.584 μg/mL。小鼠肉瘤S180移植性肿瘤模型抑制实验中,低、中、高剂量照射组的平均肿瘤抑制率分别为82.83%、88.56%、95.59%,与阴性对照组比较,差异均具有统计学意义(P<0.05)。裸鼠H460细胞荷瘤动物模型中,DVDMS-2 0.5、1.0和2.0 mg/kg对裸鼠异体移植瘤的抑制率分别为38.8% 、47.9%和53.9%,与阴性对照组比较,差异均具有统计学意义(P <0.05)。结论：DVDMS-2体内外应用对肿瘤生长均有明显的抑制作用。     

Interstitial photodynamic therapy. Clinical experience with diffusing fibres in the treatment of cutaneous and subcutaneous tumours.

Interstitial photodynamic therapy has a number of potential advantages over superficial treatment. We have treated 50 subcutaneous and cutaneous tumours interstitially, in nine patients. An additional 22 tumours in the same patients, were treated by superficial PDT. Patients received 1.5-2.0 mg kg-1 of polyhaematoporphyrin and 72 h later underwent treatment using a copper vapour dye laser producing red light at 630 nm. All interstitial treatments were delivered using cylindrical diffusing fibres and a wide range of light doses (5-1500 J cm-3). The complete response rate for all tumours treated interstitially was 52%, rising to 81% in those patients who received 2.0 mg kg-1 PHP and light doses in excess of 500 J cm-3. The overall incidence of skin necrosis was 32% and was 79% in those treated with light doses of greater than 500 J cm-3. The incidence of skin necrosis with interstitial PDT is lower than that seen with superficial photodynamic therapy but higher volumetric light doses are required to produce tumour complete responses. All treatments were well tolerated and volumes of tumour up to 60 cm3 were successfully treated. The penetration depth of 630 nm light in human breast cancer tissue was determined as 4 mm. Little true tumour tissue selectivity was detected by analysis of porphyrin levels in biopsy material.     

Role of thromboxane and prostacyclin release on photodynamic therapy-induced tumor destruction

Thromboxane and prostacyclin levels in serum were measured following photodynamic therapy (PDT) to assess the role of these vasoactive agents on vascular damage and tumor destruction. Sprague Dawley rats were given injections i.v. of Photofrin II doses ranging from 0 to 25 mg/kg. Twenty-four h later, the right hindlimbs of animals bearing chondrosarcoma tumor or controls were exposed to 0-135 J/cm2 630 nm light. Serum concentrations of thromboxane and prostacyclin were determined by radioimmunoassay. A dose-response relationship was established between the amount of photosensitizer administered and the light dose delivered with the release of thromboxane immediately following PDT. Treatment of tumor induced higher levels of thromboxane than did the treatment of tumor-free tissue, suggesting that tumor is more sensitive to PDT-induced damage. The porphyrin and light doses found to induce the release of thromboxane into serum were the same as those required to evoke vascular stasis and tumor destruction. Prostacyclin release was not altered by PDT. The administration of indomethacin (10 mg/kg, i.p.) 3 h before light treatment was found to suppress the intravascular release of thromboxane at the highest porphyrin and light doses studied. Indomethacin treatment also inhibited PDT-induced vascular stasis and tumor destruction, suggesting that the release of thromboxane is linked to these events. Since prostacyclin levels in serum were unchanged following PDT treatment of tumor and controls, thromboxane release appears to be a specific response to PDT and may mediate the vascular stasis observed following PDT.     

510.6nm绿色铜蒸气激光加血卟啉衍生物(HpD)对动物移植瘤杀伤作用的实验研究

本文报告510.6nm绿色铜蒸气激光与HpD对动物移植瘤的杀伤作用.给带S_(180)和B_(16)—MB小鼠腹腔注射HpD50mg/kg,注后72小时,用510.6mm铜蒸气激光照射肿瘤,照后肿瘤体积和重量,均明显减少(P<0.01和<0.05),病理检查照区肿瘤均有坏死,深度为5.5～8.8mm,平均约7mm,单纯铜激光照射,肿瘤坏死深度最大达5mm.HpD组和非激光非HpD组无上述变化.HpD对小鼠B_(16)—MB生长抑制试验,未显示其本身抑制肿瘤生长的作用.本实验结果表明510.6nm铜激光对癌细胞杀伤作用是肯定的,可作为浅表癌肿PDT治疗的光源.     

Inducing effect of hematoporphyrin derivative (HpD) on cell sister chromatid exchanges (SCE) in vitro

The mutagenic effect of HpD on cell SCE and the reactions of cell SCE to different sources of light combined with HpD were studied using V79 cells. There were 6 doses of HpD: 1 microgram/ml, 3 micrograms/ml, 5 micrograms/ml, 10 micrograms/ml, 50 micrograms/ml and 100 micrograms/ml. The dose of 5 micrograms/ml is equal to the maximum dose of HpD used in the clinic (HpD per milliliter of patient's blood). Our experiments demonstrated that when the cells were cultured in the dark and HpD was added to the medium no more than 5 micrograms/ml, the SCE frequencies were not increased. The cells were irradiated with different sources of light without HpD, both the fluorescence and ultraviolet light could promote SCE but the light of daylight lamp and red light did not increase it. But when HpD was added into culture medium at the dose of less than 5 micrograms/ml, every light could increase the cell SCE intensively except the daylight lamp light. The red light was more notable than the others by relation analysis.