Photodynamic therapy of lung cancer with photosensitizers based on polycationic derivatives of synthetic bacteriochlorin (experimental study)

BACKGROUND

One of the tasks of anticancer photodynamic therapy is increasing the efficacy of treatment of cancer nodes with large (clinically relevant) sizes using near-infrared photosensitizers (PS).

METHODS

The anticancer efficacy and mechanisms of the photodynamic action of PS based on polycationic derivatives of synthetic bacteriochlorin against Lewis lung carcinoma were studied in vitro and in vivo.

RESULTS

It was found that studied PS have high phototoxicity against Lewis lung carcinoma cells: the IC50 values were about 0.8 μM for tetracationic PS and 0.5 μM for octacationic PS. In vivo studies have shown that these PS provide effective inhibition of the tumor growth with an increase in the lifespan of mice in the group by more than 130%, and more than 50% survival of mice in the group.

CONCLUSIONS

Photosensitizers based on polycationic derivatives of synthetic bacteriochlorin have high photodynamic efficacy caused by the induction of necrosis and apoptosis of cancer cells, including cancer stem cells, and a sharp decrease of mitotic and proliferative activity. Studied polycationic photosensitizers are much more effective at destroying cancer stem cells and newly formed cancer vessels in comparison with anionic photosensitizers, and ensure the cessation of tumor blood flow without hemorrhages and thrombosis.

Photodynamic therapy procedures in coronavirus (COVID-19) outbreak: perception of health risks among clinical dental faculty and dental students

OBJECTIVE

The aim of the study was to investigate clinical faculty members and final year dentistry students' perceptions regarding their health concerns and risks of performing photodynamic therapy (PDT) procedure in dental clinics amidst the COVID-19 pandemic.

SUBJECTS AND METHODS

A 21-item questionnaire comprising open and closed questions was sent to dental faculty members (n=43) and final year dentistry students (n=99) of Riyadh Elm University during mid-January 2021 that ended only after two weeks. The survey included health risks perception of performing PDT procedures, the impact of the COVID-19 outbreak on PDT performance and stress levels, perceived efficacy of the preventive steps, perception of the effect of the probable suspension of PDT procedure in dental clinics, and influence of alternative teaching methods of PDT procedure on clinical competence were reported.

RESULTS

A response rate of 82% for faculty members (n=35) and 75% for students (n=74) was recorded. 91% of faculty members and 95% of students felt that their health was not at risk during performing PDT procedure in dental clinics amidst the COVID-19. 82% of faculty and 83% of students expressed that the PPE and universal preventive steps to perform PDT procedure were enough for preventing the cross-infection with the virus. 89% of faculty members and 91% of students thought that a provisional suspension of PDT procedures in dental clinics would assist in containment of the virus and reduce the infection risk from the contact and not the PDT procedure.

CONCLUSIONS

Students and faculty members reported that their health is not at risk while performing PDT procedure in dental clinics amidst the COVID-19 outbreak.

Enhanced reduction of polymicrobial biofilms on the orthodontic brackets and enamel surface remineralization using zeolite-zinc oxide nanoparticles-based antimicrobial photodynamic therapy

The aim of this study was to evaluate the anti-biofilm and anti-metabolic activities of zeolite-zinc oxide nanoparticles (Zeo/ZnONPs)-based antimicrobial photodynamic therapy (aPDT) against pre-formed polymicrobial biofilms on the orthodontic brackets, as well as, assess the remineralization efficacy on polymicrobial biofilms induced enamel lesions. Following synthesis and characterization of Zeo/ZnONPs, cell cytotoxicity, hemolytic effect, and intracellular reactive oxygen species (ROS) production were determined. The anti-biofilm and anti-metabolic activities of aPDT using different concentrations of Zeo/ZnONPs were investigated. Microhardness tester and DIAGNOdent Pen were used to evaluate the changes of remineralization degree on the treated enamel slabs duration 1 and 3 months. No significant cytotoxicity and erythrocyte hemolysis were observed in treated cells with Zeo/ZnONPs. When irradiated, suggesting that the Zeo/ZnONPs were photoactivated, generating ROS and leading to reduce dose-dependently the cell viability and metabolic activity of polymicrobial biofilms. Also, the enamel surface microhardness value of exposed enamel showed a steady increase with the concentration of Zeo/ZnONPs. No statistically significant differences were shown between aPDT and sodium fluoride varnish as the control group. Overall, Zeo/ZnONPs-based aPDT with the greatest remineralization efficacy of enamel surface can be used as an anti-biofilm therapeutic method, which is involved with their potent ability to produce ROS.

Contemporary approaches and future perspectives of antibacterial photodynamic therapy (aPDT) against methicillin-resistant Staphylococcus aureus (MRSA): A systematic review

The high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) causing skin and soft tissue infections in both the community and healthcare settings challenges the limited options of effective antibiotics and motivates the search for alternative therapeutic solutions, such as antibacterial photodynamic therapy (aPDT). While many publications have described the promising anti-bacterial activities of PDT in vitro, its applications in vivo and in the clinic have been very limited. This limited availability may in part be due to variabilities in the selected photosensitizing agents (PS), the variable testing conditions used to examine anti-bacterial activities and their effectiveness in treating MRSA infections. We thus sought to systematically review and examine the evidence from existing studies on aPDT associated with MRSA and to critically appraise its current state of development and areas to be addressed in future studies. In 2018, we developed and registered a review protocol in the International Prospective Register of Systematic Reviews (PROSPERO) with registration No: CRD42018086736. Three bibliographical databases were consulted (PUBMED, MEDLINE, and EMBASE), and a total of 113 studies were included in this systematic review based on our eligibility criteria. Many variables, such as the use of a wide range of solvents, pre-irradiation times, irradiation times, light sources and light doses, have been used in the methods reported by researchers, which significantly affect the inter-study comparability and results. On another note, new approaches of linking immunoglobulin G (IgG), antibodies, efflux pump inhibitors, and bacteriophages with photosensitizers (PSs) and the incorporation of PSs into nano-scale delivery systems exert a direct effect on improving aPDT. Enhanced activities have also been achieved by optimizing the physicochemical properties of the PSs, such as the introduction of highly lipophilic, poly-cationic and site-specific modifications of the compounds. However, few in vivo studies (n = 17) have been conducted to translate aPDT into preclinical studies. We anticipate that further standardization of the experimental conditions and assessing the efficacy in vivo would allow this technology to be further applied in preclinical trials, so that aPDT would develop to become a sustainable, alternative therapeutic option against MRSA infection in the future.

Baseline factors predicting the need for corneal crosslinking in patients with keratoconus

INTRODUCTION

The primary purpose of crosslinking is to halt the progression of ectasia. We retrospectively assessed the condition of keratoconus patients who were followed-up at least twice after the initial examination to evaluate keratoconus progression, to identify definitive factors to predict a later need for corneal crosslinking (CXL).

METHODS

The medical charts of 158 eyes of 158 keratoconus patients (112 males and 46 females; mean age, 27.8 ± 11.7 years), who were followed up at the Department of Ophthalmology, Keio University School of Medicine at least twice after the initial examination to evaluate keratoconus progression were retrospectively reviewed. Best-spectacle corrected visual acuity, intraocular pressure, steepest corneal axis on the anterior float (Ks), thinnest corneal thickness according to Pentacam® HR, and corneal endothelial cell density were assessed. Gender, age, onset age of keratoconus, history of atopic dermatitis, and Pentacam® indices were also recorded. CXL was performed when the eye showed significant keratoconus progression, an increase in the steepest keratometric value, or an increase in the spherical equivalent or cylinder power of the manifest refraction by more than 1.0 D versus the respective values 2 years prior. Predictor variables and the requirement for CXL were analyzed using logistic regression.

RESULTS

Fifty-eight eyes required CXL treatment. The best predictor of the requirement for CXL was patient age, followed by the Pentacam® Rmin (the minimum sagittal curvature evaluated by Pentacam®) value. The incidence of CXL was 86.4% in the < 20 years age group, with an Rmin of ≤ 5.73 mm, whereas 10.8% in the ≥ 27 years age group with an Rmin > 5.73 mm underwent treatment.

CONCLUSIONS

An age of < 20 years and an Rmin value of ≤ 5.73 mm predicted keratoconus progression and the requirement for CXL treatment in the near future.

Iridium(III) Complex-Derived Polymeric Micelles with Low Dark Toxicity and Strong NIR Excitation for Phototherapy and Chemotherapy

Iridium(III) complexes are potent candidates for photodynamic therapy. However, their clinical usage is impeded by their poor water solubility, high dark toxicity, and negligible absorption in near-infrared region (NIR region). Here, it is proposed to solve these challenges by developing an iridium(III) complexe-based polymeric micelle system. This system is self-assembled using an iridium(III) complex-containing amphiphilic block polymer. The upconversion nanoparticles are included in the polymeric micelles to permit NIR excitation. Compared with the nonformulated iridium(III) complexes, under NIR stimulation, this polymeric micelle system exhibits higher ¹ O₂ generation efficiency, negligible dark toxicity, excellent tumor-targeting ability, and synergistic phototherapy-chemotherapy effect both in vitro and in vivo.

[Approaches to phototherapy in children with chronic dermatosis (review of literature)]

The article covers main aspects of phototherapy and photochemotherapy in treatment of skin diseases in children, risks of such methods usage, prophylactic and therapeutic measures, and precaution means for such treatment in pediatrics.

Photobleaching-based dosimetry predicts deposited dose in ALA-PpIX PDT of rodent esophagus

An improved method to estimate dose to esophageal tissue was investigated in the setting of photodynamic therapy with aminolevulinic acid-induced protoporphyrin IX (PpIX) treatment. A model of treatment-induced edema in the esophagus mucosa proved to be a well controlled and useful way to test the dosimetry model, and the light from the treatment laser together with the PpIX fluorescence intensity could be quantified reliably in real time. Dosimetry calculations based upon the detected fluorescence and bleaching kinetics were used to calculate the "effective" dose to the tissue, and a correlation was shown to exist between this metric and the edema induced in the esophagus. The difference between animals with no detectable treatment effect and those with significant edema was predictable based upon the dose calculation. The underlying assumption in the interpretation of the data is that rapid photobleaching of PpIX occurs when there is ample oxygen supply, and this bleaching is not present when oxygen is limited. This leads to the prediction that integration of the light and drug dose, in intervals where appreciable photobleaching occurs, should provide a prediction of the relative dose of singlet oxygen produced. This detection system and rodent model can be used for prospective dosimetry studies that focus on optimization of esophageal PDT.

Efficacy of Photodynamic Therapy in the Management of Occult Choroidal Neovascularization Associated with Serous Pigment Epithelium Detachment

AIMS

To evaluate the efficacy of photodynamic therapy (PDT) in the treatment of subfoveal occult choroidal neovascularization (CNV) associated with serous pigment epithelium detachment (PED) in eyes with age-related macular degeneration.

METHODS

Hundred and fifty-three patients (161 eyes) with subfoveal occult CNV due to age-related macular degeneration, were divided into two groups. The first group (70 patients, 75 eyes) included eyes with occult CNV associated with serous PED of at least 1 disc diameter in size and the second (83 patients, 86 eyes) eyes with late leakage of undetermined source. All the patients were treated with PDT. The follow-up time ranged from 12 to 48 months.

RESULTS

At the last examination, in the first group, the visual acuity (VA) improved or remained stable in 17 (22.7%) and decreased in 58 (77.3%). In the second group, the VA improved or remained stable in 37 (43%) and decreased in 49 (57%). The difference in the change (decrease) in the VA between the two groups was statistically very significant (p = 0.0075). Retinal pigment epithelium tear occurred in 15 eyes (20%) of the first group.

CONCLUSION

Our study showed that the visual prognosis of eyes treated with PDT due to subfoveal occult CNV associated with serous PED is not favorable. We believe that the distinction between the two forms of occult CNV is essential, as they carry a different prognosis.

Subclinical photodynamic therapy treatment modifies the brain microenvironment and promotes glioma growth

Photodynamic therapy (PDT) has been clinically investigated as an adjuvant local therapy for brain tumors. Therapeutic interventions intended to promote tumor cell death can also promote changes in the tumor microenvironment that could favor tumor growth. We have previously shown that PDT can activate pro-angiogenic factors in the normal rodent brain. This study seeks to further elucidate the effects of subtherapeutic doses of Photofrin-PDT on normal brain and to establish a mouse model for studying glioma progression in an environment modified by oxidative stress. Photofrin was administered to nude mice, and a defined intracranial area was illuminated with laser to deliver an optical dose equivalent to 80 J/cm(2). Three and 7 days after PDT, mice were sacrificed and brains were fixed and analyzed by immunohistochemistry. PDT treatment resulted in transient increase in cell proliferation, associated with a robust activation of astrocytes and microglia in the treated region, without causing substantial cell death. To test how this modified environment would affect glioma growth, human glioblastoma U87 cells were implanted in the PDT-treated hemisphere or in the control brain subjected to sham surgery. Significantly larger tumors were observed after 3 weeks in the PDT treated brains relative to control treatment. Our results indicate that subclinical Photofrin-PDT locally alters the brain homeostasis without inflicting significant disruption to the tissue architecture, providing a model to study the effects of the microenvironment on glioma growth, with implications for the optimization of the clinical use of PDT for brain tumors.

Photobleaching-based dosimetry predicts deposited dose in ALA-PpIX PDT of rodent esophagus

An improved method to estimate dose to esophageal tissue was investigated in the setting of photodynamic therapy with aminolevulinic acid-induced protoporphyrin IX (PpIX) treatment. A model of treatment-induced edema in the esophagus mucosa proved to be a well controlled and useful way to test the dosimetry model, and the light from the treatment laser together with the PpIX fluorescence intensity could be quantified reliably in real time. Dosimetry calculations based upon the detected fluorescence and bleaching kinetics were used to calculate the "effective" dose to the tissue, and a correlation was shown to exist between this metric and the edema induced in the esophagus. The difference between animals with no detectable treatment effect and those with significant edema was predictable based upon the dose calculation. The underlying assumption in the interpretation of the data is that rapid photobleaching of PpIX occurs when there is ample oxygen supply, and this bleaching is not present when oxygen is limited. This leads to the prediction that integration of the light and drug dose, in intervals where appreciable photobleaching occurs, should provide a prediction of the relative dose of singlet oxygen produced. This detection system and rodent model can be used for prospective dosimetry studies that focus on optimization of esophageal PDT.

Porphycenes: Facts and Prospects in Photodynamic Therapy of Cancer

The photodynamic process induces cell damage and death by the combined effect of a photosensitizer (PS), visible light, and molecular oxygen, which generate singlet oxygen ((1)O(2)) and other reactive oxygen species that are responsible for cytotoxicity. The most important application of this process with increasing biomedical interest is the photodynamic therapy (PDT) of cancer. In addition to hematoporphyrin-based drugs, 2nd generation PSs with better photochemical properties are now studied using cell cultures, experimental tumors and clinical trials. Porphycene is a structural isomer of porphyrin and constitutes an interesting new class of PS. Porphycene derivatives show higher absorption than porphyrins in the red spectral region (lambda > 600 nm, epsilon > 50000 M-(1)cm(-1)) owing to the lower molecular symmetry. Photophysical and photobiological properties of porphycenes make them excellent candidates as PSs, showing fast uptake and diverse subcellular localizations (mainly membranous organelles). Several tetraalkylporphycenes and the tetraphenyl derivative (TPPo) induce photodamage and cell death in vitro. Photodynamic treatments of cultured tumor cells with TPPo and its palladium(II) complex induce cytoskeletal changes, mitotic blockage, and dose-dependent apoptotic or necrotic cell death. Some pharmacokinetic and phototherapeutic studies on experimental tumors after intravenous or topical application of lipophilic alkyl-substituted porphycene derivatives are known. Taking into account all these features, porphycene PSs should be very useful for PDT of cancer and other biomedical applications.

Guidelines on the use of photodynamic therapy for nonmelanoma skin cancer: An international consensus

Topical photodynamic therapy (PDT) is used to treat nonmelanoma skin cancers, such as actinic keratoses, Bowen's disease, and basal cell carcinoma (superficial and nodular). This article presents up-to-date, practical, evidence-based recommendations on the use of topical PDT using 5-aminolevulinic acid or methyl aminolevulinate for the treatment (and prevention) of nonmelanoma skin cancers. A systematic literature review was conducted (using MEDLINE), and recommendations were made on the basis of the quality of evidence for efficacy, safety/tolerability, cosmetic outcome, and patient satisfaction/preference. Topical PDT is highly effective in the treatment of actinic keratoses, Bowen's disease, superficial and thin nodular basal cell carcinomas, with cosmesis typically superior to that achieved with existing standard therapies. PDT may also be a means of preventing certain nonmelanoma skin cancers in immunosuppressed patients.

Fluorescence diagnosis of bladder cancer

Standard management of newly presenting superficial bladder tumours is to remove the tumour endoscopically and to administer a single dose of a chemotherapeutic agent into the bladder postoperatively. However, between 20-40% of patients will develop a tumour in the bladder again within 12 months (Herr, 1997). There is controversy about whether these tumours are genuine recurrences or previously undetected tumours. Photodynamic diagnosis is currently the subject of clinical trials for detection and surveillance of bladder cancer. A solution is administered into the bladder preoperatively which is absorbed by the cancer cells. These areas within the bladder then fluoresce under blue light, aiding the surgeon to detect tumours that may not have been visible to the naked eye. The authors present a review of this developing technique and their early experiences of photodynamic diagnosis in clinical trials which appear to be clinically relevant in decreasing recurrent bladder tumours.

Light distribution and calibration of commercial PDT LED arrays

Commercial photodynamic therapy (PDT) light sources are supplied with no evidence of traceability to national measurements standards to validate indicated delivered dose. Also, the spatial distribution of the radiant energy is not disclosed. This means that there is no way for the user to be able to verify that the required dose is being delivered to the appropriate area of the lesion. To this end, a simple method, traceable to national standards, is described and applied to an investigation of two commercial LED arrays. In one case, the dose fell to 38% of that received at the central area at a distance of only 2 cm. In the other, the output was more uniform over a larger area but the maximum irradiance was not at the centre of the field. All of these inhomogenieties were taken into account when the actual light dose delivered to the patient was calculated in the method described. This ensured transparent traceability in PDT dosimetry.

Consciousness and Quantum Information Processing: Uncovering the Foundation for a Medicine of Light

Great progress has been made by Russian and German researchers in recent years (Popp, Voeikov, and others) to examine the biophysical aspects of biophotonic processes in humans. This paper suggests that there is a many-body reality to the way biophysical light interacts with the human self-organization of information that may be achieved by means of biomolecular, metabolic, or neural communication. These systems may merge as mobile energy relay systems similar to what is seen as qi processes in acupuncture science, suggesting a "holomovement" that seeks to confirm itself and increasingly retrieves and uses only the information that serves its exchanges with the environment. This coevolution of evolutionary process levels, expressed in process terms, can be seen as a foundation for a Medicine of Light integrating hidden variables in consciousness studies with functional differentiation and new findings in the biologic sciences.

Standardizing dosimetry in esophageal PDT: an argument for use of centering devices and removal of misleading units

A simple standardization of esophageal photodynamic therapy light dosimetry is proposed. Calculations of the effect on local treatment dose of using non-centered diffusing fibers have been made and the methods of calculating light energy dose to the treatment area within a centering balloon are discussed. A requirement for centering devices and standard units of Joules per cm(2) of treatment area are indicated.

Laser targeted photo-occlusion of rat choroidal neovascularization without collateral damage

Laser targeted photo-occlusion (LTO) is a novel method being developed to treat choroidal neovascular membranes (CNV) in age-related and other macular degenerations. A photosensitive agent, encapsulated in heat-sensitive liposomes, is administered intravenously. A low power laser warms the targeted tissue and releases a bolus of photosensitizer. The photosensitizer is activated after it clears from the normal choriocapillaris but not from the CNV. Forty-five experimental CNV were induced in seven rats. Five weeks after LTO, complete occlusion was observed by laser targeted angiography (LTA) in 76% of treated CNV, and partial occlusion was found in the remaining 24%. The tissues outside the CNV but within the area treated by LTO showed no flow alteration and no dye leakage. All untreated CNV were patent on LTA at 5 weeks. Light microscopy and electron microscopy confirmed the results in treated and control lesions. Moreover, treated areas next to lesions showed normal photoreceptors, retinal pigment epithelium (RPE), Bruch's membrane and choriocapillaris. These results indicate that LTO may improve current photodynamic therapy by alleviating the need for repeated treatments and by avoiding the long-term risks associated with damage to the RPE and occlusion of normal choriocapillaries.

[Age-related macular degeneration--a public health problem]

Verteporfin for the treatment of age related macular degeneration was identified as a potential breakthrough technology by the Working Group on Medical Procedures of the German Standing Committee of Physicians and Sickness Funds in spring 2000. Consequently, a formal review was undertaken to assess the benefits and risks of this treatment in order to evaluate its future status in German statutory ambulatory health care. The treatment effect of verteporfin was established in a high quality randomized controlled trial, for the predominantly wet, classic type of choroidal neovascularization secondary to age related macular degeneration. For this patient group, verteporfin is regarded as a reasonable and necessary procedure as there is no effective alternative therapy for this type of macular degeneration. However, the treatment stabilizes the patient's vision rather than improves it and the long term effects must still be evaluated in further clinical trials. After a thorough review of the scientific literature and the statements of various stakeholders the Standing Committee decided to introduce this technology into the statutory healthcare benefits package. For the most effective use of this treatment it must be assured that, prior to treatment, the AMD type (wet vs. dry, classic vs. occult) is correctly diagnosed (using fluorescein angiography) and documented by specially trained physicians. For this reason a stringent quality assurance guideline was developed to prevent the use of this costly technology for non-approved indications. Further indications for this therapy are currently under evaluation in randomized controlled trials. Hence, this decision will need to be updated in future.

Long-term results in the treatment of vitiligo with oral khellin plus UVA

This study was performed to assess the effectiveness and short-term and long-term safety of oral khellin plus UVA (KUVA) in patients with vitiligo. Twenty-eight patients (13 males and 15 females; mean age, 34 years; [age range, 15-51 years]) most with extensive generalized vitiligo of more than 6 months duration had received KUVA at sometime during a 14-year period. The response to treatment (i.e. repigmentation of depigmented areas) was rated retrospectively comparing photographs taken before and after therapy and correlation analysis revealed that it was statistically significantly linked to the number of KUVA treatments (r = 0.833, P = 0.001) and to total cumulative UVA dose (r = 0.840, P = 0.001). Of 17 patients who had continued therapy for longer than 3 months, 7 (41%) had a good response (i.e., more than 70% repigmentation of lesional skin) after a mean of 194 treatments (range, 69-386 treatments) and a mean cumulative UVA dose of 2,036 J/cm2 (range, 690-4,411 J/cm2), whereas lower response grades were observed in the patients with lower treatment numbers. The most common short-term side effect was mild nausea, occurring in 8 of 28 patients (29%), and mainly in the first week(s) of treatment. Follow-up assessment at a mean of 40 months (range, 4-110 months) after the end of KUVA therapy available in 23 of 28 patients revealed no skin cancers or actinic skin damage in any patient. These data indicate that KUVA seems to be safe as well as effective for vitiligo, provided treatment is administered long enough.

Photodynamic therapy for advanced bile duct cancer: evidence for improved palliation and extended survival

Median survival time of nonresectable hilar bile duct cancer is only 4 to 6 months owing to tumor spread in the biliary tree, refractory cholestasis, and sepsis or liver failure. We explored whether local photodynamic therapy of nonresectable bile duct cancer could improve survival. A sample size of 23 patients is required to detect an increase in 6-month survival rate from less than 50% to greater than 70% in a single-arm phase-II trial with a statistical power of 80% (Fleming's single step procedure; alpha = 0.05). Twenty-three consecutive patients (8 women, 15 men; 67 +/- 14 years) with nonresectable bile duct cancer (Bismuth type III n = 2, type IV n = 21) were treated with photodynamic therapy and biliary endoprosthesis. Photofrin (QLT Pharmaceuticals, Vancouver, Canada) (2 mg/kg body weight intravenously) was photoactivated after 1 to 4 days with laser light (630 nm; 242 J/cm(2)) via endoscopic retrograde access. The 6-month survival rate was 91% after diagnosis and 74% after start of photodynamic therapy (30-day mortality rate was 4%) at a median follow-up time of 10.3 months after diagnosis. Causes of death were tumor progression (n = 9) and bacterial infections (n = 4). The median rate of local tumor response was 74%, 54%, 29%, and 67% after the first, second, third, fourth, and fifth photodynamic therapy. Time to progression ranged from 3 to 8 months. All patients, except 1 with diffuse liver metastases, improved in cholestasis, performance, and quality of life. Photodynamic therapy can prevent tumor occlusion of hilar bile ducts. The apparent benefit in survival time should be confirmed in a controlled trial versus palliation by endoprosthesis only.

Photopheresis for ARC: a nursing perspective

Photopheresis, an approved treatment for cutaneous T-cell lymphoma (CTCL), is the basis of a trial involving patients with AIDS-related complex (ARC). This study has provided the opportunity to identify unique nursing challenges along with satisfaction from innovative nursing interventions.

Inefficacy of extracorporeal photochemotherapy in the treatment of B-cell chronic lymphocytic leukemia: preliminary results

Because extracorporeal photopheresis has been shown to be clinically effective in Sezary syndrome, a disease characterized by a circulating malignant clone, we initiated a pilot study of its use in B-cell chronic lymphocytic leukemia (B-CLL) to see if it could be similarly effective. We treated three patients with Rai stage III and IV B-CLL with photopheresis (3 consecutive days a week every 3 weeks) and followed serial clinical and immunologic parameters. While we noted no major toxicity, there was neither clinical response to treatment nor marked improvement in white counts or mitogen assays. We conclude that photopheresis was not effective in inducing remission in this pilot study of advanced stage B-CLL patients.

Photodynamic therapy: status and potential

Photodynamic therapy (PDT) uses drugs which, while pharmacologically inactive, can be activated in vivo by visible or near infrared light to produce a local toxic reaction (photosensitizers). Photofrin II (PII) is a mixture of oligomeric porphyrins which accumulate and are retained over several days in all malignant tissue at levels generally higher than surrounding epithelial tissues. Following activation by red light, generally obtained from a laser and delivered by simple quartz fiber optics, PII produces a photochemical generation of cytotoxic singlet oxygen that destroys the tissue in which it resides. Several thousand cancer patients with both early and advanced tumors have been treated to date with encouraging results. Phase III comparative, controlled clinical trials are underway for photodynamic treatment of tumors of the bladder, esophagus, and bronchus.