Porphyria in animals

Porphyrins are found to be widely, although erratically, distributed throughout the animal kingdom. It would indeed have been surprising had it been otherwise since the tetrapyrrole ring system is a key material used in hemoproteins and essential for all biologic oxidative metabolism in the fabric of life. Those anaerobes, which possess no cytochromes or other hemoproteins, may be regarded as degenerate forms in which this biosynthetic ability has been lost. The porphyrins are stable chemical materials that have been detected in fossil shells from the post-Pleistocine and upper-Eocene deposits and are thus many millions of years old.^1,2 In the lower phyla, the black slug, Arion, contains great quantities of uroporphyrin. Among the higher forms of animal life, the group of birds known as the Turacos or plantain-eaters are unique in having utilized the copper complex of uroporphyrin III, called turacin,³ for the deep red areas of pigmentation in their flight feathers (Fig. 1) although there seems to be nothing otherwise unusual about the porphyrin metabolism of these birds.⁴ Other birds also have porphyrins in their feathers and down^5–7 and porphyrins are used in the coloration of eggs. Among the mammals, a few genera appear normally to produce much more porphyrin than others and these belong to the family of rodents. The rat excretes a relatively large quantity of protoporphyrin, which arises by synthesis in Harder's glands.⁸     

Association of HPV with human genital tumors

Human papillomaviruses (HPV) are clearly responsible for the induction of genital lesions like condylomata acuminata, bowenoid papules, and flat condylomas. Moreover, the DNA of particular virus types (HPV16 and 18) is found in a substantial number of invasively growing squamous cell carcinomas of the genital tract, suggesting an etiologic involvement of these viruses in tumor development.

Since HPV16 and 18 as well as other papillomaviruses (HPV6 or 11) usually present within the benign genital warts can be found in dysplastic lesions of the uterine cervix known as putative precancerous lesions, determination of the virus type might be of diagnostic relevance. Since no type-specific serologic reagents are available, viruses can be identified by nucleic acid hybridization using radioactively labeled HPV DNAs that have been molecularly cloned as probes.     

Identification of papillomaviruses in butchers' warts

We have studied the papillomaviruses found in the hand warts of 60 butchers, most of them from 2 distant slaughterhouses. Warts differing in morphology and location were studied separately. The viruses were identified by molecular hybridization, restriction enzyme analysis and immunofluorescence. Four known human papillomaviruses (HPV-1, HPV-2, HPV-3, HPV-4) were detected and one hitherto unknown papillomavirus was identified in 9 butchers. The DNA of the latter virus did not anneal with any of the RNAs complementary to either HPV-1 to HPV-5 or bovine papillomavirus type 1 (BPV-1) DNAs, and showed a Hind II + III restriction enzyme cleavage pattern distinct from those of known HPVs and BPVs. This virus showed distinct antigenic properties, as shown by immunofluorescence, using HPV-1, -2, -3, -5, and BPV-1 antisera. It may represent a new type of human papillomavirus (HPV-7) or a yet unidentified animal papillomavirus. In addition, 6 butchers were found to be infected with a papillomavirus, distinct from the known skin HPVs and from BPV-1, which could not be characterized by restriction enzyme analysis. Eleven butchers were found to be infected by 2 viruses. A characteristic histological pattern was found to be associated with the different papillomaviruses.     

Papillomaviruses pathogenic to human and their relationship to oncogenesis

In recent times, modern gene technology has led to a new understanding of the role of the human papillomaviruses in the development of some malignant tumours in humans. As a result, models based on molecular-biological analysis of the interactions between papillomaviruses and tumour cells have been developed. Cancer appears to be the result of inadequate control of the host cell over persisting viral genes. Virus infection is the necessary precondition for malignancy, but it is not sufficient to trigger the growth of a tumour. This can only occur if the cellular control genes are impaired possibly as the result of a mutagenic effect of simultaneous factors such as recurrent infections, UV radiation, X-rays, or chemical carcinogens.     

High albumin levels restrict the kinetics of 13-cis retinoic acid uptake and intracellular isomerization to all-trans retinoic acid and inhibit its anti-proliferative effect on SZ95 sebocytes

13-cis Retinoic acid is rapidly absorbed into cells and exerts its anti-proliferative effect on human sebocytes by specific isomerization to high levels of all-trans retinoic acid and binding the retinoic acid receptors. In this study, we have shown that bovine serum albumin, an extracellular binding protein for 13-cis retinoic acid, plays an important part in the uptake of 13-cis retinoic acid in human sebocytes, its intracellular isomerization to all-trans retinoic acid, and the induction of its anti-proliferative effect. The addition of highly concentrated bovine serum albumin (20 mg per ml) to the serum-free maintenance medium resulted in a rather controlled uptake of constant levels of 13-cis and all-trans retinoic acid into the cells over the 72 h of treatment. As a consequence, significantly reduced and delayed isomerization of 13-cis retinoic acid to all-trans retinoic acid was detected. In parallel experiments, the anti-proliferative activity of 13-cis retinoic acid on SZ95 sebocytes was abrogated by adding 20 mg bovine serum albumin per ml into the serum-free medium. These results indicate a critical function of serum albumin as retinoid-binding protein in reducing the concentration of active retinoids and restricting their biologic effects on human sebocytes.     

Natural cell-mediated cytotoxicity against various target cells in patients with epidermodysplasia verruciformis

Natural cell-mediated cytotoxicity of peripheral blood mononuclear cells was studied in eight patients with epidermodysplasia verruciformis induced by human papillomaviruses specific for epidermodysplasia verruciformis and in five patients with epidermodysplasia verruciformis-induced exclusively by human papillomavirus type 3. Nine patients with various cutaneous warts and 25 age- and sex-matched healthy persons were control subjects. Natural cell-mediated cytotoxicity against both K-562 erythroleukemic and Sk-v cells was in the normal range in patients with epidermodysplasia verruciformis induced by epidermodysplasia verruciformis-specific human papillomaviruses and in patients with cutaneous warts. The lysis of both targets, however, was significantly decreased in patients with the form of epidermodysplasia verruciformis associated with human papillomavirus type 3. Experiments with normal keratinocytes and with keratinocytes isolated from a malignant lesion bearing human papillomavirus type 5 genomes showed that the latter were susceptible to lysis by the peripheral blood mononuclear cells of healthy persons and of patients with cutaneous warts. Lysis of keratinocytes in epidermodysplasia verruciformis, however, was strongly reduced in patients with epidermodysplasia verruciformis induced by specific human papillomaviruses. This reduction was not associated with a decrease in anti-K-562 natural cell-mediated cytotoxicity. Our results suggest that in patients with epidermodysplasia verruciformis induced by disease-specific human papillomaviruses, there is reduced natural cell-mediated cytotoxicity against epidermodysplasia verruciformis keratinocytes.     

Shope rabbit papillorna-carcinoma complex a model system of HPV infections

To the busy, practicing dermatologist, an animal model system may appear to offer little benefit to patient diagnosis or management; however, animal model systems often can provide answers to vexing clinical problems that cannot be approached in patient studies because of ethical restrictions or logistic problems. Animal models are imperfect substitutes for human diseases; but because they share similar mechanisms, an animal model can provide an opportunity to test hypotheses that contribute to an understanding of the human counterparts.

The Shope rabbit papilloma is remarkably similar in etiology and mechanism to many naturally occurring lesions induced by human papillomaviruses. In that sense, the Shope system can contribute to an understanding of human wart-virus infections. In a broader context, the Shope papilloma-carcinoma complex can provide an understanding of the determinants of neoplastic progression and of host interactions with neoplastic tissue.

The purpose of this report will be to review some of the more important aspects of this experimental tumor system, especially those that are relevant to clinical situations. This review will be limited in scope. For more detailed coverage, the reader is referred to another article which we published elsewhere.¹     

The role of human papillomavirus in carcinoma.

Human papillomaviruses have long been identified as the cause of common warts and condylomata acuminata. Evidence is now accumulating that human papillomaviruses may be involved in not only benign, but also in malignant neoplasms. They might also be significant in the malignant transformation of cutaneous neoplasms. This review examines the oncogenic potential of human papillomaviruses when they are found in carcinomas in various anatomic areas, including the skin.     

Localized epidermotropic reticulosis (Woringer-Kolopp disease)

In order to clarify the biologic behavior and establish clinical and histologic criteria for the diagnosis of a cutaneous disease originally described by Woringer and Kolopp, we examined fifteen new cases and reviewed thirteen reports. The disease presents as a single, chronic, asymptomatic, circinated, scaly plaque. It preferably involves distal extremities and affects middle-aged individuals, as well as a considerable number of youths. The male to female ratio is 2:1. The treatment of choice is surgical excision or radiotherapy. One lesion resolved with an intralesionally administered steroid. Follow-up data of the twenty-eight cases suggest that this is a benign lesion. Paradoxically, its atypical microscopic features contrast with its benign clinical appearance and biologic behavior. The lower epidermis appears focally infiltrated by large atypical mononuclear cells that spare the dermis. Ultrastructural observations suggest that these are stimulated T lymphocytes, which sometimes are mixed with histiocytes. We propose the term "localized epidermotropic reticulosis" for this distinct clinicopathologic entity, which is different from mycosis fungoides.     

Characteristics of cultivated adult human nevocellular nevus cells

Nevus cells are of biologic interest because of their uncertain relationship to epidermal melanocytes and of clinical interest because of their statistical association with melanoma. We report a technique that allows reliable cultivation of nevus cells from small acquired and congenital nevi and permits in vitro characterization of this cell type. Morphologically, cultured nevus cells were found to closely resemble epidermal melanocytes from the same or comparably aged donors, manifesting marked dendricity and specific ultrastructural features characteristic of melanocytes; but could be distinguished by the presence of occasional large binucleate or trinucleate cells and by the frequent finding of grouped melanosomes in nevus cell cytoplasm. Growth kinetics were also similar for nevus cells and epidermal melanocytes, with population doubling times of 1-2 weeks in hormone-supplemented serum-free medium, and substantial growth enhancement by fetal bovine serum. As previously noted for epidermal melanocytes, nevus cells in serum-free culture demonstrated striking substrate responsiveness, with far greater attachment rates and degree of cytoplasmic spreading on fibronectin or type I/III collagen than on laminin, type IV collagen, or uncoated plastic. These strong similarities in vitro suggest that morphologic and behavioral differences observed between epidermal melanocytes and nevus cells in the skin may result from local environmental influences rather than from intrinsic cellular differences. The availability of a satisfactory culture system for nevus cells may facilitate future investigations into their malignant potential and other biologic features.     

High prevalence of a variety of epidermodysplasia verruciformis-associated human papillomaviruses in psoriatic skin of patients treated or not treated with PUVA.

Epidermodysplasia verruciformis-associated human papillomaviruses and in particular human papillomavirus type 5 were recently shown to be highly prevalent in psoriatic skin. We have analyzed lesional skin from 54 psoriasis patients for infections with genital-specific and epidermodysplasia verruciformis-specific human papillomaviruses to define the spectrum of involved human papillomavirus types and to test if it is influenced by psoralen ultraviolet A therapy. Using polymerase chain reaction analysis we could detect human papillomavirus sequences in skin lesions of 83% of the tested patients. In contrast, human papillomavirus-DNA was only demonstrated in 19% of skin samples from 42 dermatologically healthy, immunocompetent individuals. Sequence analysis of the polymerase chain reaction amplimers revealed 14 human papillomavirus types, all belonging to the epidermodysplasia verruciformis or epidermodysplasia verruciformis-related papillomaviruses. Only in one case we identified sequences related to those of genital viruses, which, however, represented a putatively new human papillomavirus type. The most prevalent human papillomavirus type in our patient series was human papillomavirus type 36, found in 62% of the patients positive for human papillomavirus-DNA, followed by human papillomavirus type 5 (38%) and human papillomavirus type 38 (24%). Multiple infections with two to five different human papillomavirus types could be detected in skin samples of 63% of the analyzed patients. The overall human papillomavirus detection rate did not differ significantly between patients which have been subjected to psoralen ultraviolet A photochemotherapy or solely treated with topical preparations (77 vs 89%). Human papillomavirus type 5, however, could be detected significantly more frequent in lesions of psoralen ultraviolet A-treated patients (p < 0.001). Our data strongly argue for infections with epidermodysplasia verruciformis-specific papillomaviruses being an almost consistent feature of the lesional psoriatic skin and substantiate the importance of further studies to elucidate a possible involvement of human papillomaviruses in psoriasis pathology.     

Control of connective tissue metabolism by lasers: Recent developments and future prospects

Various laser modalities are currently in extensive use in dermatology and plastic surgery, particularly for treatment of vascular and pigmented lesions. A relatively new area of laser utilization involves the possible biologic effects of the lasers. In this overview, we are summarizing our recent studies, which indicate that lasers at specific wavelengths and energy densities modulate the connective tissue metabolism by skin fibroblasts both in vitro and in vivo. Specifically, the neodymium-yttrium-aluminum-garnet (Nd: YAG) laser was shown to selectively suppress collagen production both in fibroblast cultures and in normal skin in vivo, thus suggesting that this laser modality may be useful for the treatment of fibrotic conditions such as keloids and hypertrophic scars. Furthermore, two low-energy lasers, helium-neon (He-Ne) and gallium-arsenide (Ga-As), were shown to stimulate collagen production in human skin fibroblast cultures, suggesting that these lasers could be used for enhancement of wound healing processes. These experimental approaches illustrate the future possibilities for applying lasers for the modulation of various biologic functions of cells in tissues and attest to the potential role of lasers in the treatment of cutaneous disorders.     

Growth rate of cultured human fibroblasts increased by glucocorticoids

Selected glucocorticoids have been demonstrated to increase the growth rate of human skin fibroblasts in culture, over a physiologically significant concentration range. At the same concentrations and identical conditions, the glucocorticoid compounds tested inhibited the growth rate of mouse L-929 cells. We have discussed currently acceptable theories of glucocorticoid mechanism of action that permit this dichotomous effect, the main point being that inhibition can no longer be regarded as the only response of fibroblasts to glucocorticoids. Conclusions drawn from observations of cell cultures affected by addition of glucocorticoids must have considered the source of the cells, as response may vary with source and biologic state of the cells in culture.     

In vitro lessons for wound healing

To understand a process as complex as wound healing, it is helpful to compartmentalize it. This is necessary if one is to study specific aspects individually. For the present purpose, wound healing can be subdivided into four phases: wounding, inflammation, cellular proliferation, and remodeling or maturation. Wound healing may also be considered under the temporally overlapping requirements for cellular migration, division, and differentiation or production of specialized products. Each of these discrete phenomena is potentially amenable to in vitro investigation.Recent advances in tissue culture techniques have greatly expanded the opportunity for clinically relevant, scientifically rigorous studies of wound healing. The following discussion focuses on selected applications of current methodology to this complex biologic process. It is intended to be illustrative of questions that can be addressed in vitro, not as a comprehensive review of the area.     

Inmunogenicidad en terapia biológica. Implicaciones en Dermatología

It is now known that all biologic drugs, even those that are fully human, are immunogenic, that is, they have the ability to induce an immune response in the treated patient. Since the presence of antidrug antibodies may influence the levels and function of the drug in the body, this immune response can alter the efficacy of the biologic treatment and even its safety profile, depending on the mechanism of action (neutralizing or nonneutralizing) and/or an accelerated clearance of the drug. Immunogenicity is a dynamic factor that should be taken into account when prescribing biologic therapy in psoriasis, especially in the case of long-term treatment and when assessing secondary loss of response. An understanding of the immunogenicity of biologic therapies and how this can be managed is useful not only for optimizing the treatment strategy used with each drug, but also for designing predictive models of response and even for tailoring therapy on a case-by-case basis.     

Biologic therapy improves psoriasis by decreasing the activity of monocytes and neutrophils

Therapy with monoclonal antibodies to tumor necrosis factor (TNF)‐α and the interleukin (IL)‐12/23 p40 subunit has significantly improved the clinical outcome of patients with psoriasis. These antibodies inhibit the effects of the target cytokines and thus the major concern during their use is the induction of excessive immunosuppression. Recent studies evaluating the long‐term efficacy and safety of biologic therapy in psoriasis have shown no significant appearance of serious adverse effects including infections and malignancies. However, the immunological consequence and the mechanism by which the blockade of a single cytokine by biologics can successfully control the activity of psoriasis remain unclear. In the current study, we investigated the effect of biologic therapy on cytokine production of various lymphocytes and on the activity of monocytes and neutrophils in psoriatic patients. Neutrophils, monocytes and T cells were purified from heparinized peripheral venous blood by Ficoll density gradient centrifugation, and γ‐interferon, TNF‐α and IL‐17 production from lymphocytes was measured by flow cytometer. The activation maker of neutrophils and the activated subsets of monocytes were also analyzed. Biologic therapy induced no significant changes in the cytokine production by lymphocytes from the skin and gut‐homing T cells. However, neutrophil activity and the ratio of activated monocyte population increased in severely psoriatic patients were normalized in psoriatic patients receiving biologic therapy. The present study showed that biologic therapy ameliorates clinical symptoms and controls the immune response in patients with psoriasis.     

The spermicide nonoxynol-9 does not inactivate papillomavirus.

Vaginal spermicides are effective contraceptive, and are also capable of inactivating many sexually transmitted pathogens by their detergent effect on bacterial cell membranes and viral envelopes. A 5% concentration of nonoxynol-9, the most frequently used active ingredient of spermicides, was tested for its ability to reduce the transforming activity of bovine papillomavirus type 1 (BPV-1), and the infectivity of BK virus (BKV) and cytomegalovirus (CMV). Nonoxynol-9 markedly reduced the infectivity of CMV, an enveloped virus, but did not significantly affect the activity of the nonenveloped viruses BPV-1 and BKV. Papillomavirus infections are strongly implicated in the etiology of cervical cancer. The reported protective effect of vaginal spermicides against cervical cancer is very likely not mediated by direct inactivation of papillomaviruses by the spermicide.     

Reacciones paradójicas de los tratamientos biológicos utilizados en psoriasis: revisión de la literatura

Biologic drugs, which are molecules designed to act on specific immune system targets, have been shown to be very effective in treating various dermatological, rheumatological, and systemic diseases. As a group, they have an acceptable safety profile, but their use has been associated with the onset of both systemic and organ-specific inflammatory conditions. True paradoxical reactions are immune-mediated disorders that would usually respond to the biologic agent that causes them. There is still debate about whether certain other adverse reactions can be said to be paradoxical. The hypotheses proposed to explain the pathogenesis of such reactions include an imbalance in cytokine production, with an overproduction of IFN-α and altered lymphocyte recruitment and migration (mediated in part by CXCR3), and the production of autoantibodies. Some biologic therapies favor granulomatous reactions. While most of the paradoxical reactions reported have been associated with the use of TNF-α inhibitors, cases associated with more recently introduced biologic therapies —such as ustekinumab, secukinumab, and ixekizumab— are increasingly common. The study of paradoxical adverse events not only favors better management of these reactions in patients receiving biologic therapy, but also improves our knowledge of the pathogenesis of chronic inflammatory diseases and helps to identify potential therapeutic targets.     

Syringocystadenoma papilliferum associated with verrucous carcinoma of the skin in the same lesion: Report of four cases

The association of syringocystadenoma papilliferum (SCAP) with verrucous carcinoma (VC) of the skin in the same lesion is a rare, but well-documented event. Although human papillomaviruses (HPV) have been proposed to have an etiologic role in the development of the verrucous proliferations associated with SCAP, most of the immunohistochemical and molecular studies have failed to show the presence of their genomic material in these lesions. We report a series of four cases of SCAP associated with VC in anogenital lesions. In two of the cases, we demonstrated the presence of the BRAF ^V600E mutation by polymerase chain reaction and immunohistochemistry, both in the glandular and in the squamous component. No HPV-related histopathologic changes were found, nor could the presence of viral DNA be showed.     

Biologic therapeutics in the treatment of psoriasis. Part 1: review

BACKGROUND: Psoriasis is a chronic inflammatory skin disease principally mediated by activated T cells, which release proinflammatory cytokines with reactive epidermal changes in the skin, producing the characteristic lesions of psoriasis. New research into possible treatment options has been inspired by increased understanding of the pathophysiology of psoriasis and advances in immunology and molecular biology permitting the development of targeted, highly active biologic agents. OBJECTIVE: The aim of this article is to review the efficacy and safety of five biologic therapeutics in the treatment of moderate to severe psoriasis and to provide practical guidelines for integration of these agents in the management of psoriasis. METHODS: We searched MEDLINE (1966-2005) for articles containing the key words: alefacept, efalizumab, etanercept, infliximab, and adalimumab and searched recent conference abstracts. RESULTS: Emerging immunotherapeutic agents (fusion proteins, recombinant cytokines, fusion toxins, or antibodies) target T cells or cytokines responsible for plaque formation that is characteristic of psoriasis. Alefacept is the first biologic to be approved in both the United States and Canada. More recently, efalizumab and etanercept and infliximab have been approved in the United States and Canada for plaque-type psoriasis. Adalimumab is currently in phase III clinical trials. CONCLUSION: These novel biologics offer an intriguing and effective treatment option for patients with moderate to severe psoriasis.