Angelicin: A leading culprit involved in fructus Psoraleae liver injury via inhibition of VKORC1

ETHNOPHARMACOLOGICAL RELEVANCE

The adverse effects of Fructus Psoraleae (FP), especially liver injury, have attracted wide attention in recent years.

AIM OF THE STUDY

To establish a system to explore potential hepatotoxic targets and the chief culprit of liver injury based on clinical experience, network pharmacological method, molecular docking, and in vitro and in vivo experiments.

MATERIALS AND METHODS

Clinical applications and adverse reactions to FP were obtained from public literatures. Components absorbed in the blood were selected as candidates to search for potential active targets (PATs) of FP. Subsequently, potential pharmacological core targets (PPCTs) were screened through the "drug targets-disease targets" network. Non-drug active targets (NPATs) were obtained by subtracting the PPCTs from the PATs. The potential hepatotoxic targets (PHTs) of FP were the intersection targets obtained from Venn analysis using NPATs, hepatotoxic targets, and adverse drug reaction (ADR) targets provided by the databases. Then, potential hepatotoxic components and targets were obtained using the "NPATS-component" network relationship. Molecular docking and in vitro and in vivo hepatotoxicity experiments were performed to verify the targets and related components.

RESULTS

Overall, 234 NPATs were acquired from our analysis, and 6 targets were identified as PHTs. Results from molecular docking and in vitro and in vivo experiments showed that angelicin is the leading cause of liver injury in FP, and VKORC1 plays an important role.

CONCLUSION

The results indicate that six targets, especially VKORC1, are associated with the PHTs of FP, and angelicin is the leading culprit involved in FP liver injury via inhibition of VKORC1.

Angelicin Alleviates Maternal Isoflurane Exposure-Induced Offspring Cognitive Defects Through the Carbonic Anhydrase 4/Aquaporin-4 Pathway

An increasing number of studies reveal the deleterious effects of isoflurane (Iso) exposure during pregnancy on offspring cognition. However, no effective therapeutic strategy for Iso-induced deleterious effects has been well developed. Angelicin exerts an anti-inflammatory effect on neurons and glial cells. This study investigated the roles and mechanism of action of angelicin in Iso-induced neurotoxicity in vitro and in vivo. After exposing C57BL/6 J mice on embryonic day 15 (E15) to Iso for 3 and 6 h, respectively, neonatal mice on embryonic day 18 (E18) displayed obvious anesthetic neurotoxicity, which was revealed by the elevation of cerebral inflammatory factors and blood-brain barrier (BBB) permeability and cognitive dysfunction in mice. Angelicin treatment could not only significantly reduce the Iso-induced embryonic inflammation and BBB disruption but also improve the cognitive dysfunction of offspring mice. Iso exposure resulted in an increase of carbonic anhydrase (CA) 4 and aquaporin-4 (AQP4) expression at both mRNA and protein levels in vascular endothelial cells and mouse brain tissue collected from neonatal mice on E18. Remarkably, the Iso-induced upregulation of CA4 and AQP4 expression could be partially reversed by angelicin treatment. Moreover, GSK1016790A, an AQP4 agonist, was used to confirm the role of AQP4 in the protective effect of angelicin. Results showed that GSK1016790A abolished the therapeutic effect of angelicin on Iso-induced inflammation and BBB disruption in the embryonic brain and on the cognitive function of offspring mice. In conclusion, angelicin may serve as a potential therapeutic for Iso-induced neurotoxicity in neonatal mice by regulating the CA4/AQP4 pathway.

Lemons in the Arizona Sunshine: The Effects of Furocoumarins Leading to Phytophotodermatitis and Burn-like Injuries

INTRODUCTION

Phytophototoxic dermatitis is a strong phototoxic reaction to ultraviolet A (UV-A) radiation exposure after cutaneous contact with citrus fruit containing furocoumarins, leading to skin injury. At the Arizona Burn Center (Phoenix, AZ), the majority of these injuries are managed in the outpatient setting.

CASE REPORT

The authors present a pediatric admission for burn-like injuries following prolonged cutaneous exposure to lemons while playing in the Arizona sunshine. A 7-year-old girl playing in her backyard squeezed lemon juice onto her skin while in the hot Arizona sunshine; within 24 hours, the child experienced pain, erythema, and blistering to multiple areas of her skin. She was admitted to the authors' burn center for wound care and pain control. She had scattered first-degree and second-degree burn-like lesions to her face, neck, and chest as well as bilateral forearms, hands, lower extremities, and feet. After blister debridement, appropriate dressing care, and pain medication, the patient was discharged home after 4 days of hospitalization with appropriate clinical follow-up.

CONCLUSIONS

Burn-like lesions caused by furocoumarins after cutaneous absorption and UV-A exposure are known clinical entities in Arizona. The sequential progression from erythema to blisters equivalent to second-degree burn-like lesions to cutaneous hyperpigmentation is a well-described clinical triad. Meticulous wound care and pain control for the treatment of these burn-like lesions are essential as is the need for the wound care specialist to be well versed on this topic to quickly identify the etiology of the injury, thereby avoiding misdiagnosing the patient with nonaccidental traumatic injuries.

[Sosnowsky's hogweed - toxicology and threat to health]

Sosnowsky's hogweed (Heracleum sosnowskyi Manden.) is a genus of plants in the family Apiaceae which also includes Giant Hogweed (Heracleum mantegazzianum Sommier and Levier). They are both found in Central Europe, mainly in neglected green areas or riversides. Sosnowsky's hogweed was brought to Poland from the Soviet Union in the 1950s to be used in animal feed production. Intended goals couldn't be achieved and the plant spread throughout grounds distant to the primarily cultivated lands. Sosnowsky's hogweed is especially hazardous in direct contact with human skin. It results from the content of photoallergic substances called furanocoumarins in its essential oil. Clinically it is presented as burns, mainly of 2nd and 3rd degree. They mostly occur on the face, upper and lower limbs. Typical symptoms include pain, redness, swelling and heat in the area of exposure. Their extent depends on burn's depth and area and also on time of exposure to plant's toxins. In this article we present Sosnowsky's hogweed's activity and its influence on human health.

[The effect of drugs used in treatment of skin disorders on visual system]

Drugs with side effects affecting vision are often used in the treatment of skin disorders. The study evaluated principal groups of medicines which may negatively influence vision and the eye itself. Antimalaric drugs may cause a number of disorders of vision and a diagnosed retinophaty is an absolute contraindication. Retinoids often cause a dry eye condition, which results in intolerance to wearing contact lenses. They can also be a cause of poor nightly vision. Psoralens, used in photochemotherapy, can penetrate to the frontal part of the eye, inducing clouding of the lens and cataract. Glucocorticosteroids, often used in skin conditions, increase intraocular pressure, which may result in development of glaucoma. Methotrexate may also cause complications, such as eyelid edema, conjunctival hyperemia, increased lacrimation and photophobia. A prolonged use of tetracyclines may induce side effect in eye organs. Swelling of the optic nerve head with subsequent decreased vision, and even accumulate of metabolites of tetracycline within the conjunctival were observed. In the study a distinction was made between the medications which may lead to a temporary visual impairment and the medication with a side effect lasting beyond the treatment. It was pointed out that some of the side effects could be avoided or minimised by not combining retinoids and tetracyclines or with the use of protective eyewear during photochemotherapy. An examination by ophthalmologist is a crucial step prior to the treatment with chloroquine, hydroxychloroquine or psoralens. Regular eye exams are necessary when using, especially in a protracted fashion, most of the discussed drugs. Finally, the cooperation between dermatologist and ophthalmologist is fundamental for ensuring patient's safety.

A prospective, active haemovigilance study with combined cohort analysis of 19,175 transfusions of platelet components prepared with amotosalen-UVA photochemical treatment

BACKGROUND AND OBJECTIVES

A photochemical treatment process (PCT) utilizing amotosalen and UVA light (INTERCEPT(™) Blood System) has been developed for inactivation of viruses, bacteria, parasites and leucocytes that can contaminate blood components intended for transfusion. The objective of this study was to further characterize the safety profile of INTERCEPT-treated platelet components (PCT-PLT) administered across a broad patient population.

MATERIALS AND METHODS

This open-label, observational haemovigilance programme of PCT-PLT transfusions was conducted in 21 centres in 11 countries. All transfusions were monitored for adverse events within 24 h post-transfusion and for serious adverse events (SAEs) up to 7 days post-transfusion. All adverse events were assessed for severity (Grade 0-4), and causal relationship to PCT-PLT transfusion.

RESULTS

Over the course of 7 years in the study centres, 4067 patients received 19,175 PCT-PLT transfusions. Adverse events were infrequent, and most were of Grade 1 severity. On a per-transfusion basis, 123 (0.6%) were classified an acute transfusion reaction (ATR) defined as an adverse event related to the transfusion. Among these ATRs, the most common were chills (77, 0.4%) and urticaria (41, 0.2%). Fourteen SAEs were reported, of which 2 were attributed to platelet transfusion (<0.1%). No case of transfusion-related acute lung injury, transfusion-associated graft-versus-host disease, transfusion-transmitted infection or death was attributed to the transfusion of PCT-PLT.

CONCLUSION

This longitudinal haemovigilance safety programme to monitor PCT-PLT transfusions demonstrated a low rate of ATRs, and a safety profile consistent with that previously reported for conventional platelet components.

Drug-induced nail disorders

Nail disorders are defined according to their appearance and the part of the nail affected: the nail plate, the tissues that support or hold the nail plate in place, or the lunula. The consequences of most nail disorders are purely cosmetic. Other disorders, such as ingrown nails, inflammation, erythema, abscesses or tumours, cause functional impairment or pain. The appearance of the lesions is rarely indicative of their cause. Possible causes include physiological changes, local disorders or trauma, systemic conditions, toxic substances and drugs. Most drug-induced nail disorders resolve after discontinuation of the drug, although complete resolution sometimes takes several years. Drugs appear to induce nail disorders through a variety of mechanisms. Some drugs affect the nail matrix epithelium, the nail bed or the nail folds. Some alter nail colour. Other drugs induce photosensitivity. Yet others affect the blood supply to the nail unit. Nail abnormalities are common during treatment with certain cytotoxic drugs: taxanes, anthracyclines, fluorouracil, EGFR, tyrosine kinase inhibitors, etc. Some drugs are associated with a risk of serious and painful lesions, such as abscesses. When these disorders affect quality of life, the benefits of withdrawing the drug must be weighed against the severity of the condition being treated and the drug's efficacy, taking into account the harm-benefit balance of other options. Various anti-infective drugs, including tetracyclines, quinolones, clofazimine and zidovudine, cause the nail plate to detach from the nail bed after exposure to light, or cause nail discoloration. Psoralens and retinoids can also have the same effects.

Phytophotodermatitis

Phytophotodermatitis is a phototoxic cutaneous eruption due to skin exposure to furocourmarins combined with ultraviolet light. Bizzare linear patterns, ranging from erythema to bullae with residual hyperpigmentaion, is the clinical clue to this diagnosis. Avoidance of furocoumarins in direct sunlight can prevent recurrences.

Food-drug interactions: grapefruit juice

Food-drug interactions are increasingly recognized as important clinical events which may change significantly the bioavailability of oral administrated drugs. Grapefruit juice (GFJ) demonstrated multiple interactions with drugs leading to loss of the therapeutic effects or increased side-effects. GFJ decreases pre-systemic metabolism through a) competitive or mechanism-based inhibition of gut wall CYP3A4 isoenzymes and b) P-glycoprotein (P-gp), c) multidrug resistance protein-2 (MRP2) or d) organic anion-transporting polypeptide (OATP) inhibition. Although, GFJ presents high amounts of flavonoids (e.g. naringin, naringenin), furanocoumarins (e.g. 6',7'-dihydroxybergamottin, bergamottin) are the main chemicals involved in the pharmacokinetic interactions. As compounds of GFJ show additive or synergistic effects, all the major furanocoumarins are necessary for the maximal inhibitory effect. Also, related citrus fruits (sweeties, pummelo and sour orange) or various plants containing furanocoumarins may present pharmacological interactions, yet to be discovered.

Drug-induced photosensitivity

(1) Photosensitivity reactions are cutaneous disorders due to exposure to ultraviolet (UV) radiation of natural or artificial origin. They occur or are more prevalent on unprotected skin. The main clinical manifestations are burns, eczema-like rash, urticaria, pigmentation, or onycholysis; (2) Many drugs increase cutaneous sensitivity to UV, sometimes for therapeutic purposes, but it is generally an unwanted effect.

Phytophotodermatitis in Rijeka region, Croatia

Contact with plants can cause phototoxic or rarely photoallergic reactions. Phototoxic dermatitis (photophytodermatitis) occurs after contact or ingestion of plants containing furocumarins i.e. psoralens and followed by sun exposure. Skin lesions develop usually after 24-48 hours with erythema, bulla formation, itch or pain, followed by a long lasting hyperpigmentation. Furocumarins can be linear i.e. psoralens (5-MOP, 8-MOP), or angular like angelicin and pimpinellin. Their binding to DNA causes cellular damage. This can happen in florists, gardeners, farmers, horticulturists, food handlers, and botanists. The plants causing phototoxic reaction can vary with the local flora but are commonly a member of the family apiaceae (formerly umbelliferae), family rutaceae, leguminosae and moraceae. The authors give special consideration to the phytophotodermatitis that appeared in their region in spring and summer during a three year period.

Heracleum mantegazzianum and Toxicodendron succedaneum: plants of human health significance in New Zealand and the National Pest Plant Accord

New Zealand's National Pest Plant Accord (NPPA) is a voluntary and cooperative agreement between industry, regional councils, and central government departments with biosecurity responsibilities (primarily the Ministry of Agriculture and Forestry and the Department of Conservation). Plant species included in the NPPA are declared unwanted organisms under the Biosecurity Act 1993, which prevents their sale, propagation, or distribution across the country. Although MAF Biosecurity New Zealand (the lead agency in New Zealand's biosecurity system) has evaluated the potential human health impacts of 202 species considered for inclusion in the NPPA, two species were examined primarily due to their significance to human health: Heracleum mantegazzianum (giant hogweed, cow parsnip, wild parsnip) and Toxicodendron succedaneum (rhus tree, wax tree, Japanese wax tree). As a result of this process, H. mantegazzianum has been listed in the NPPA. In contrast, T. succedaneum was not included in the NPPA, as the latter was deemed to be an inappropriate mechanism for its control. In this article the NPPA process is outlined, and the adverse impacts on human health of these two species are discussed--including symptoms, treatment, and possible management measures.

Burns caused by accidental overdose of photochemotherapy (PUVA)

This study was aimed to alert the hazard of accidental adverse reactions of photochemotherapy (Psoralen-UVA or PUVA) that has been used in the treatment for some skin diseases and commercially for cosmetic tanning. Aside from the predictable side effects of PUVA such as erythema and itching, the accidental adverse reactions such as extensive burns could occasionally occur. Our observations indicated that six cases resulted from mistakes of medical personnel, and six other cases resulted from unsupervised mistakes of patients. The conditions that needed photochemotherapy were seven cases of vitiligo, three cases of psoriasis and two cases of tanning. The accidental overdose of UV radiation was about 3-10 times the empirically normal dose. Five of our patients were supposed to undergo topical PUVA, but they were irradiated at the dose of oral PUVA. One patient applied 8-methoxypsoralen (8-MOP) cream together with taking 5-methoxypsoralen (5-MOP) tablets for oral PUVA. Three other patients enjoyed sunbathing 1-3h shortly after finishing PUVA. A young couple chose 5-MOP to enhance tanning and sunbathed about 1h later. When another patient resumed PUVA in a 6-month cessation, he was exposed at a previous dose instead of a starting dose. Erythema and blisters of second degree burns developed in all our cases, 36-72h after PUVA, with 5-25% of body surface involved. Among the 12 patients, 3 were admitted and 9 were treated on an outpatient basis. All patients recovered in 1-3 weeks with no skin graft or no significant sequelae except post-inflammatory hyperpigmentation.

Documento de consenso sobre la modalidad terapéutica del baño-PUVA

Bath PUVA is a variant of phototherapy as efficacious as oral PUVA therapy that avoids many of the adverse effects associated to this treatment. Nevertheless, the special features and the specialized equipment required for its employment have limited its application in the dermatologic clinics of our country. Following the trend initiated after the publication of the consensus document on oral PUVA therapy and narrow band (NB) UVB therapy, the Spanish Photobiology Group from the Spanish Academy of Dermatology and Venereology has developed a therapeutic guideline for bath PUVA therapy based on the literature review and the experience of its members. The document aims to be a practical reference guide for those dermatological centres that include phototherapy among their services. It reviews the concept and indications of this type of treatment and proposes recommendations concerning therapeutic procedures, drug associations of interest and prophylaxis and management of adverse effects.

Can dietary furanocoumarin ingestion enhance the erythemal response during high-dose UVA1 therapy?

As phototoxic skin reactions caused by psoralen are induced by wavelengths within the UVA1 spectrum, we assessed the potential of the small amount of psoralen in a normal diet to provoke phototoxicity in volunteers with skin types I and II. Threshold erythema was unaffected by ingestion of a 200-g portion of parsnip.

The many faces of phytophotodermatitis

Phytophotodermatitis is a common cutaneous phototoxic reaction produced by contact with a variety of plant substances, followed by sunlight exposure. Phytophotodermatits can simulate child abuse, impetigo, superficial lymphangitis, and larva migrans. The most frequent presentation is hyperpigmentation of the dorsum of the hands, but there are other less common findings such as blisters or lesions mimicking solar lentigines and melasma.

Assessing phytophotodermatitis: boy with erythema and blisters on both hands

Phytophotodermatitis (PPD) is a phototoxic reaction which occurs when the skin comes in contact with a photosensitizer and is subsequently exposed to radiation. PPD is often seen in people handling furocoumarin-containing products, such as agricultural workers, bartenders, florists, and gardeners. It may also be seen in beachgoers, athletes, and children. The pattern of the lesions usually resembles streaks; the hands and mouth are most commonly affected due to eating and handling of the offending furocoumarin-containing agents.

Therapeutic efficacy and safety of photochemically treated apheresis platelets processed with an optimized integrated set

BACKGROUND

This multicenter, randomized, controlled, double-blind Phase III clinical study evaluated the therapeutic efficacy and safety of apheresis platelets (PLTs) photochemically treated (PCT) with amotosalen and ultraviolet A light (INTERCEPT Blood System, Baxter Healthcare Corp.) compared with conventional apheresis PLTs (reference).

STUDY DESIGN AND METHODS

Forty-three patients with transfusion-dependent thrombocytopenia were randomly assigned to receive either PCT or reference PLT transfusions for up to 28 days.

RESULTS

The mean 1- and 24-hour corrected count increments were lower in response to PCT PLTs (not significant). When analyzed by longitudinal regression analysis, the estimated effect of treatment on 1-hour PLT count was a decrease of 7.2 x 10(9) per L (p = 0.05) and on 24-hour PLT count a decrease of 7.4 x 10(9) per L (p = 0.04). Number, frequency, and dose of PLT transfusions; acute transfusion reactions; and adverse events were similar between the two groups. There was no transfusion-associated bacteremia. Four PCT patients experienced clinical refractoriness; however, only one exhibited lymphocytotoxicity assay seroconversion. Antibodies against potential amotosalen-related neoantigens were not detected.

CONCLUSION

PCT PLTs provide effective and safe transfusion support for thrombocytopenic patients.

[Photobiophysics of furanocoumarins]

Furocoumarins (psoralens) are photosensitizers of plant origin, which increase the sensitivity of biological objects to near ultraviolet (UV-A, 320-400 nm). In combination with UV-A, they are successfully used for treating many dermal and autoimmune diseases (PUVA therapy and photophoresis). Along with therapeutic effects, the furocoumarin photochemotherapy induces a number of side-effects (erythema, edema, hyperpigmentation, and premature aging of skin). All photobiological effects of furocoumarins result from their photochemical reactions. Therefore, in order to advance the therapy, it is necessary to know the photochemical mechanisms of induction of both side- and therapeutic effects. The types of photoreactions of furocoumarins classified with respect to reactive photoproducts interacting with substrate were considered. Primary emphasis was placed on reactions proceeding with the participation of photooxidation products of furocoumarins. Among these photoproducts, at least two types can be distinguished. Some of them possess membranotoxic properties, others produce the immunosuppressory action in vivo. The photochemical mechanisms of the formation of the photoproducts of furocoumarins are different. It was found that, by varying the illumination conditions (intensity of UV-A radiation or the concentration of the photosensitizer), it is possible to obtain the photoproducts of furocoumarins that have either membranotoxic or immunosuppressory properties. It was found that the mechanisms of the immunosuppressive action of the photooxidation products of furocoumarins have some features in common with those underlying the PUVA therapy and photophoresis. It is assumed that the photochemical basis of the therapeutic action of furocoumarins is the reactions with the involvement of the products of their photooxidation.

An Unusual Cause of Burn Injury: Fig Leaf Decoction Used as a Remedy for a Dermatitis of Unknown Etiology

Medicinal plant extracts are commonly used worldwide. Their use relies mostly on historical and anecdotal evidence and might be so hazardous. Phytophotodermatitis is a well-known entity that is caused by the sequential exposure to certain species of plants containing furocoumarins and then to sunlight. In this article, superficial burn lesions caused by fig leaf decoction that was applied to a patient's both upper extremity as a remedy for a dermatitis of unknown etiology is reported. Direct sun exposure is an essential component of phytophotodermatitis. All reported cases to date have in common that patients are exposed to direct sunlight or to artificial UVA lights (like solarium) of varying durations. In our case neither direct sun exposure, other than inevitable indoor UVA influence, nor blister formation was present. The etiologic factors, symptoms, signs, course, and treatment alternatives for phytophotodermatitis are also reviewed briefly.

[Phytodermatitis caused by burning bush of Moses]

The most well-known cause of phytophotodermatitis in Denmark is accidental contact with plants belonging to the Apiaceae (Umbelliferae), such as hodgweed (Heracleum spondylium). However, many other plants with furocoumarins (psoralens) may induce the same kind of reaction. We describe a case of phytophotodermatitis caused by Dictamnus alba, gas plant or burning bush also known from the Bible as the "burning bush of Moses".

Photoonycholysis

BACKGROUND/PURPOSE

Photoonycholysis may be seen as a part of Segal's triad, photosensitivity followed by discoloration of the nails and onycholysis. But the latter may also appear, independently, in the absence of photosensitive reaction elsewhere.

METHODS

Photoonycholysis may result from drug intake, porphyria cutanea tarda, erythropoietic porphyria, erythropoietic protoporphyria, variegate porphyria and pseudoporphyria. Rarely, spontaneous photoonycholysis may be observed.

RESULTS

Four distinct subtypes have been recorded without relationship between the responsible drugs and the different clinical varieties of photoonycholysis. Primary photohemorrhage can occur; it can also be associated with polydactylous photoonycholysis type III.

CONCLUSION

The inability to reproduce photoonycholysis experimentally should be emphasized.

Berloque dermatitis induced by "Florida water"

Phytophotodermatitis is a phototoxic dermatitis resulting from contact with psoralen-containing plants such as celery, limes, parsley, figs, and carrots. Berloque dermatitis is a variant of phytophotodermatitis and is caused by high concentrations of psoralen-containing fragrances, most commonly oil of bergamot. Berloque dermatitis is rarely seen today because of the removal of these fragrances from most cosmetic products in the United States. We report, however, a group of patients still at risk for berloque dermatitis. These patients use the colognes "Florida Water" and "Kananga Water," which are popular in Hispanic, African American, and Caribbean populations. These fragrant waters are used for spiritual blessing, treating headaches, and personal hygiene.

Zabon phytophotodermatitis: first case reports due to Citrus maxima

Zabon (Citrus maxima) is a large citrus fruit belonging to the Rutaceae family and containing a variety of psoralens including 5-methoxypsoralen. We describe the first case reports of a phytophotodermatitis caused by zabon.

Novel angular furo and thieno-quinolinones: synthesis and preliminary photobiological studies

A number of new furo and thienoquinolinones carrying an electron-withdrawing function or unsubstituted at the position 3 were synthesized in order to obtain new potential photochemotherapeutic agents with increased antiproliferative activity and decreased toxic side effects. Our interest in studying the SAR of these derivatives also prompted us to investigate the influence of N-methylation on biological activity, by preparing N-methyl derivatives. The antiproliferative activity of all the newly synthesized compounds was evaluated and compared to 8-methoxypsoralen (8-MOP), the drug widely used in PUVA-therapy. The 3-unsubstituted thienoquinolinones were generally the most potent derivatives, followed by the furo-analogues. In particular, the unsubstituted thieno[2,3-h]quinoline-2(1H)one showed the highest activity in T2 bacteriophage, HeLa cells and Ehrlich cells tests. All the compounds, assayed on Escherichia coli WP2 TM9, showed a similar mutagenic activity, very close to that of 8-MOP. Except for 2-oxo-1,2-dihydrothieno[2,3-h]quinoline-3-carboxylic acid, which appeared to be very effective, all compounds generated singlet oxygen to slightly larger amounts when compared to 8-MOP. The N-methyl analogues only induced moderate skin erythemas on albino guinea pigs, while all other derivatives appeared to be entirely inactive. On the basis of these results, the unsubstituted thieno[2,3h]quinoline 2(1H)one seems to be the most interesting potential drug for PUVA photochemotherapy and photopheresis.

Vitiligo: a retrospective comparative analysis of treatment modalities in 500 patients

The major non-surgical re-pigmenting therapies for vitiligo include psoralens and corticosteroids, used both topically and systemically. In an attempt to determine the best therapeutic option, we compared the efficacy of various treatment regimens used in our department for the treatment of vitiligo. We report herein our results with six different regimens used in our clinic. Data from five hundred vitiligo patients who attended the pigmentary disorders clinic at the Nehru Hospital, PGI, Chandigarh, was analysed. For the purpose of analysis, patients were arbitrarily divided into two groups based upon the body surface area (BSA) involved: Group A (<10% BSA involved) and B (>10% BSA involved). Group A was further divided into three subgoups of patients depending upon what treatment they received: R-I [topical clobetasol propionate+sun exposure]; R-II [topical psoralen+sun exposure (topical PUVASOL)]; R-III [topical psoralen+UVA (topical PUVA)]. Group B was also subdivided into three subgroups of patients who received: R-IV [oral dexamethasone pulse therapy + sun exposure]; R-V [systemic psoralen + sun exposure (systemic PUVASOL)]; R-VI [systemic psoralen + UVA (systemic PULVA)]. Patients who had undergone, one of the above mentioned regimens and had a regular monthly follow up until total re-pigmentation or for at least one year, whichever was earlier, were included in the final assessment of the therapeutic efficacy of that regimen. At the end of the study in Group A, 207 (89%) patients out of 232 on R-I; 73 (93%) out of 78 on R-II, and 15 (79%) out of 19 patients on R-III showed moderate to excellent re-pigmentation, respectively. In group B, 45 (81%) patients out of 55 on R-IV, 48 (84%) out of 57 on RV, and 22 (84%) patients out of 26 on R-VI showed moderate to excellent re-pigmentation. Statistically, in Group A, R-I & II were significantly better than R-III. However in Group B, there was no significant difference in the responses to R-IV, V, and VI. A positive family history of vitiligo did not seem to affect the response rate. Potent topical steroids used along with sun exposure and topical PUVASOL were the most effective forms of therapy for localised vitiligo. For the generalised form of the disease, we concluded that all the systemic modalities, oral steroids, PUVASOL and PUVA, are equally efficacious over a period of one year. Phototoxic reactions were, however, more common with PUVASOL.

Pediatric burns induced by psoralens in Saudi Arabia

Over a 5-year period, three children with psoralen-induced burns were seen. All children were on treatment for vitiligo with a psoralen oil and burns were sustained from unsupervised sun exposure while playing outdoors. The burn wound was partial thickness and involved 6-40% of the total body surface area. All wounds healed without infection or contracture with topical silver sulfadiazine. However, the previously normal skin in phototoxic areas became significantly hyperpigmented while the areas with vitiligo remained hypopigmented. Differences between psoralen-induced burns and other second degree sunburns unrelated to psoralens are discussed.

The role of PUVA in the treatment of psoriasis. Photobiology issues related to skin cancer incidence

Photochemotherapy with methoxsalen (8-methoxypsoralen) and long wavelength ultraviolet (UV) radiation (referred to as 'PUVA' for psoralen plus UVA) is commonly used to treat psoriasis and vitiligo. These vastly different diseases respond to the therapy by different mechanisms even though the immediate effects of the therapy--the photomodification of cellular biomolecules--is the same for each. Because psoriasis is not cured by PUVA, patients receive many treatments over their lifetime and have a significantly increased risk for the development of skin cancers (primarily squamous cell carcinomas). In this article the basic aspects of psoralen photobiology are reviewed briefly. Several recent studies describing the incidence of skin cancer in UVA treated psoriasis cohorts are comparatively reviewed. In addition the impact of the analysis of mutations in the tumor suppressor gene, p53, are summarized. An unexpected mutation spectrum (very few PUVA type T-->A transversions and frequent UVB solar signature C-->T transitions) suggest that effects other than direct DNA photoadduct formation may be at play. These analyses suggest that it may be possible to improve the therapeutic efficacy of PUVA by a careful evaluation of the mode of delivery. In this review the science behind PUVA is summarized. In addition, the incidence of skin cancer as a long term consequence of repeated treatments is surveyed. To relate clinical observations to molecular events, the nature of p53 mutations found in skin cancers from psoriasis patients is also analyzed. Finally some suggestions for improving the delivery of PUVA therapy are presented.

Phytophotodermatitis

This article is a concise review of phytophotodermatitis, including the mechanism involved, clinical features, and treatment options. The common culprit plant families of Umbelliferae, Rutaceae, and Moraceae are discussed along with the newly recognized St. John's Wort.

Phytophotodermatitis due to the application of citrus hystrix as a folk remedy

We report a case of extensive phytophotodermatitis in a hiker. This was caused by the application of the juice of a member of the Rutaceae family, Citrus hystrix, as a folk remedy to ward off biting insects. Besides the Rutaceae, plants belonging to the families Umbelliferae, Moraceae and Leguminosae also contain psoralens and can cause phytophotodermatitis. In temperate countries, cases are often seen among children playing outdoors during summer, when psoralens are most abundant in wild and garden plants.

Risk of melanoma with psoralen/ultraviolet A therapy for psoriasis. Do the known risks now outweigh the benefits?

Since the introduction in the 1970s of treatment with oral psoralens with longwave ultraviolet radiation in the A range (PUVA), there has been an increasing concern about the long term carcinogenic effect of the therapy. The main indication for PUVA is psoriasis, a common, chronic and intractable skin disease that affects 1 to 3% of the world's population. The effectiveness of PUVA in inducing and maintaining the remission of severe psoriasis has been amply documented. Although psoriasis is not a life-threatening disorder, it may be associated with restriction of activities and days lost to hospitalisation. Therefore, a number of systemic treatments such as methotrexate and cyclosporin have been used. None of these treatments has been as carefully studied for long term adverse effects as PUVA. The short-term adverse effects of PUVA are generally well known and tolerated. The major mid-term adverse effect, squamous cell carcinoma of the skin, has been well documented in a number of large-scale epidemiological studies that have led to recommendations such as to restrict the lifetime number of treatments. Although squamous cell carcinoma is potentially life-threatening, it is usually slow growing and can be adequately managed by proper surveillance, treatment and follow-up. The situation is quite different for malignant melanoma, which is often fast growing and fatal. Except for anecdotal reports, malignant melanoma has not been observed in PUVA patients until recently. However, a report of a cohort of 1380 patients with psoriasis has concluded that about 15 years after the first treatment the risk of melanoma is increased approximately 5-fold in patients treated with high doses. Although this report needs to be confirmed by other multicentre trials, it is alarming since the association between exposure to ultraviolet light and development of melanoma is well established both in humans and in experimental animals. Until this study is validated, it is recommended that the guidelines for PUVA therapy should be rigorously followed and that the contra-indications should be extended to include history or family history of melanoma and patients who have already received > 200 treatments.

The application of antioxidants in investigations and optimization of photochemotherapy

Psoralens (furocoumarins) are photosensitizers of plant origin. They are used in combination with near-ultraviolet (320-400 nm) light for the treatment of vitiligo, psoriasis, cutaneous T-cell lymphoma (CTCL), alopecia areata, eczema, and other skin diseases. Photobiological effects of psoralens in humans are numerous. They photosensitize erythema, hyperpigmentation, and skin aging, affect immune system, etc. Molecular mechanisms of photochemical reactions of psoralens with substrates are also numerous. The molecular basis and the relationships between different photobiological effects of psoralens remain the subject of discussion. The use of antioxidants is an essential instrument for clearing up these problems as well as for the progress of photochemotherapy. It was found that antioxidants (alpha-tocopherol, butylated hydroxytoluene, etc.) selectively inhibited the photochemical stage of erythema and hyperpigmentation but had no impact on the post-irradiation stages of these processes. Evidently, the basis of these processes is the reaction of psoralen-photosensitized oxidation of unsaturated lipids and the impairment of barrier functions of biomembranes, since the photochemical stage of these reactions is inhibited by the antioxidant. At the same time, antioxidants did not inhibit the therapeutic effect in the cases of psoriasis and CTCL. Thus, antioxidants can be used as a tool for improvement of psoralen photochemotherapy.

PUVA-induced cell mortality in NCTC 2544 keratinocytes: is it related to the microenvironmental properties of the excited states of psoralens?

The phototoxic effect of psoralen (PSO), 5-methoxypsoralen (5MOP), 8-methoxypsoralen (8MOP) and 4,5',8-trimetylpsoralen (TMP) has been compared on the NCTC 2544 keratinocyte cell line in terms of cell mortality and lipid peroxidation. The order of effectiveness for cell photokilling is TMP, 5MOP >> 8MOP, PSO, whereas a little lipid peroxidation is observed for the four psoralens under study. Oxygen-independent membrane damage seem to play a key role in the lethal photodamage because the biological effectiveness of the most hydrophobic lipid-soluble psoralens, TMP and 5MOP, is about an order of magnitude higher than that of the more water-soluble 8MOP and PSO. In relation to this hypothesis, and in contrast to 8MOP, TMP is readily extracted from cells by ethyl acetate, a good membrane solvent, as shown by GC/MS analysis on cell extracts. The results are discussed in terms of the highly microenvironment-dependent photophysical properties of psoralens. By the measure of the intracellular psoralen concentration, the neutral red uptake and the lipid peroxidation products, this work provides evidence that PUVA therapy-mediated cell mortality is a lipid peroxidation-independent phenomenon.

Dermacase. Phytophotodermatitis

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