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Biomedical subjects

W L Morison

Publications and source records attributed to W L Morison.

At least 73 records · Page 4Linked to original sources
PubMed1986

Chronic photosensitivity.

Chronic photosensitivity is an incompletely understood syndrome that is difficult to diagnose and treat. Persistent light reaction, actinic reticuloid, and photosensitive eczema most commonly occur in middle-aged and elderly patients and have overlapping features. These conditions may all be persistent light reactions to known and unknown photosensitizers. Actinic prurigo usually occurs in childhood but may be delayed in onset to adult life; it is frequently associated with atopy. The diagnosis of these conditions requires a detailed history, histologic examination of the skin, phototesting, and photopatch testing. A conservative approach to therapy consists of avoidance of the activating wavelengths and use of topical corticosteroids. However, this treatment is often unsuccessful, and PUVA therapy is an effective alternative approach.

Aged↗
PubMed1985

Methoxsalen and ultraviolet A radiation in treatment of chronic cutaneous graft-versus-host reaction.

Chronic cutaneous graft-versus-host reaction following bone marrow transplantation has been difficult to manage in some patients because of poor response to immunosuppressive agents or because of toxicity to these drugs. We recently used methoxsalen and ultraviolet A therapy and found it to be successful in controlling chronic cutaneous lichenoid graft-versus-host reaction in a bone marrow transplant patient. Although there was an initial flare of an eruption resembling acute cutaneous graft-versus-host reaction, both this acute eruption and the lichenoid lesions subsided and cleared with continued treatment. The skin lesions recurred when treatment was discontinued but responded promptly when it was initiated for the second time. Other than mild phototoxicity, there were no other significant side effects.

Adolescent↗
PubMed1985

Suppression of graft-versus-host reactivity in the mouse popliteal node by UVB radiation.

A single exposure of recipient (C57BL6 X C3H-) F1 (B6C3F1) mice to UVB radiation suppressed the graft-versus-host (GVH) reaction to injected C3H- lymphoid cells, as measured by the popliteal lymph node weight gain assay. Several observations provided evidence to suggest that this effect of UVB radiation is nonspecific and involves an alteration of the host lymphoid cell component of the reaction. First, the nonspecific trauma of mild thermal injury also suppressed the GVH reaction. Second, although treatment of mice with rose bengal and visible radiation suppresses contact hypersensitivity while treatment with eosin and visible radiation does not, both types of phototoxic treatment suppressed the GVH reaction. Third, implantation of spleens from normal B6C3F1 mice into UVB-treated or thermally injured recipient mice at the time of injection of graft cells overcame the suppression of the GVH reaction. Finally, treatment of donor B6C3F1 mice with UVB radiation did not suppress the host-versus-graft reaction in recipient C3H- mice, which suggests that radiation does not alter the stimulatory function of B6C3F1 cells. These findings are all consistent with a hypothesis that UVB radiation suppresses GVH reactivity by reducing the host component of this immune response through diversion of cells from the site of the reaction. Thus an alteration of cell trafficking appears to be an additional pathway by which UVB radiation can produce immunosuppression.

Animals↗
PubMed1985

Modulation of immune function by UV radiation.

In addition to its carcinogenic activity, ultraviolet (UV) radiation is capable of modifying certain immunologic reactions. Immunologic alterations induced in mice by UV radiation include both local and distant effects. Local alterations result from a direct effect of UV radiation on an immune reaction that takes place at the site of irradiation. Distant alterations are those in which exposure of skin to UV radiation at one site modifies an immune reaction occurring at a distant, unexposed site. Based on recent studies, we propose that there may be two types of distant alterations. One is nonspecific, may be due to accumulation of leukocytes at the site of UV-induced inflammation, and is exemplified by the suppression of delayed hypersensitivity and local graft-versus-host (GVH) reactions. The second may result from DNA damage, may involve a soluble mediator, and is manifested by the systemic suppression of contact hypersensitivity and the formation of antigen-specific suppressor T lymphocytes. These immunologic effects of exposure to UV radiation may be important in the pathogenesis of skin cancer and other cutaneous diseases.

Animals↗
PubMed1985

Effect of sunlight and its component wavebands on contact hypersensitivity in mice and guinea pigs.

Exposure of mice to UVB (280-320 nm) radiation is known to suppress the development of contact hypersensitivity (CHS) to chemicals that are applied subsequently to unirradiated skin, and this suppression is associated with the generation of suppressor lymphocytes. In this study, the systemic effect of other wavebands of nonionizing radiation on the development of CHS has been tested. Large doses of visible (greater than 400 nm) radiation produced a small but consistent systemic suppression of CHS in mice. In contrast, a large dose of UVA (320-400 nm) radiation did not suppress CHS but, rather, enhanced this immune response. Exposure of both mice and guinea pigs to sunlight produced systemic suppression of CHS. The suppression could be transferred to normal syngeneic animals by injection of splenic lymphoid cells obtained from animals that exhibited suppression, indicating that suppressor cells are associated with sunlight-induced systemic suppression of CHS. The immunomodulatory effect of sunlight was partially abrogated by a Mylar filter or prior application of a sunscreen containing para-aminobenzoic acid to the exposed skin. Thus, wavelengths mainly in the UVB portion of sunlight (295-320 nm) are responsible for sunlight-induced suppression of CHS, although wavelengths in the visible region may also play a role.

Animals↗
PubMed1985

Sunlight suppressing rejection of 280- to 320-nm UV-radiation-induced skin tumors in mice.

Repeated exposure of female C3H/HeNCR- mice to sunlight prevented the normal immunologic rejection of a UV-induced tumor. This systemic immunologic alteration was transferred to syngeneic lethally X-irradiated animals with lymphoid cells from mice exposed to sunlight. The lymphoid cells also were able to suppress the capacity of lymphoid cells from normal animals to reject a UV-induced tumor. The 295- to 320-nm wave band appeared to be responsible for this immunosuppressive effect of sunlight because suppression was prevented by filtration of the radiation through Mylar and by application of a sunscreen containing para-aminobenzoic acid. These observations may have importance in understanding the pathogenesis of sunlight-induced skin cancer in humans.

Animals↗
PubMed1985

Bullous sclerodermalike changes in chronic graft-vs-host disease.

Cutaneous sclerodermalike changes are a well-documented manifestation of chronic cutaneous graft-vs-host reaction. We describe a patient with chronic cutaneous graft-vs-host reaction who developed vesicles and bullae on sclerodermoid skin 18 months after bone marrow transplantation. The vesicles and bullae were subepidermal in location by light microscopy and were associated with dilated lymphatics and a sparse perivascular mononuclear cell infiltrate. No deposition of immunoreactants was seen by immunofluorescent microscopy. Electron microscopy confirmed the presence of a subepidermal blister beneath an intact basement membrane zone and surrounded by marked dermal edema. We postulate that localized lymphedema may play a role in the development of these vesicles and bullae.

Adolescent↗
PubMed1985

PUVA combination therapy.

Various adjunctive treatments are now frequently used in combination with PUVA therapy with the aims of limiting adverse effects, improving efficacy and decreasing the cost of treatment. In the management of psoriasis, PUVA plus retinoids, PUVA plus methotrexate and PUVA plus UVB phototherapy are the most frequently used combinations. PUVA plus topical corticosteroids and PUVA plus anthralin are also efficacious but adverse effects and poor acceptance by patients are limiting factors. Combinations of PUVA plus nitrogen mustard and ionizing radiation are used in mycosis fungoides to treat tumors and residual disease in secluded sites. In the management of photodermatoses with PUVA therapy, prednisone is often required to prevent exacerbation of disease. A combination of prednisone and PUVA therapy can also be useful in lichen planus and atopic eczema. The selection of a suitable combination treatment, will depend upon the preferences of the clinician, the disease being treated, and the characteristics of the patient.

Adrenal Cortex Hormones↗
PubMed1985

Thiazide diuretic therapy and chronic photosensitivity.

Chronic photosensitivity associated with hydrochlorothiazide ingestion occurred in four patients. These patients developed a debilitating photosensitivity that persisted for months to years even after they stopped taking the diuretic. Their age range was 44 to 66 years. Phototesting with ultraviolet B (UV-B) and ultraviolet A (UV-A) radiation revealed decreased minimal erythemal doses for one or both wave bands in all patients tested. Histologic examination of skin biopsy specimens from the patients' UV-B and UV-A test sites and lesional skin revealed an acute eczematous dermatitis. Treatment with methoxsalen and UV-A radiation successfully cleared the photosensitive eruption in the patients.

Adult↗
PubMed1985

Impaired immune function in patients with xeroderma pigmentosum.

The development of contact allergy in sun-exposed skin is markedly impaired in patients with xeroderma pigmentosum as compared to the responses in healthy control subjects. The degree of this immunological impairment is directly related to the severity of the cutaneous disease. These findings raise the possibility that sunlight-induced alterations of immune function may be involved in the marked susceptibility of these patients to the development of nonmelanoma skin cancer.

Adolescent↗
PubMed1985

Papulovesicular light eruption. A defined subset of polymorphous light eruption.

A distinctive photodermatitis is seen commonly in tourists visiting Hawaii. Analysis of 150 cases revealed that the eruption is acute in onset following exposure to sunlight, is confined to exposed areas, and mainly affects young to middle-aged white women. The clinical presentation is remarkably uniform, consisting of papules, papulovesicles, or vesicles. These findings are consistent with a diagnosis of polymorphous light eruption (PMLE) and the histologic picture supports this diagnosis. Other clinical variants of PMLE were not seen in our patients, however, which suggests that this condition is more monomorphous than polymorphous. We suggest papulovesicular light eruption as a suitable name for this common and distinctive subset of PMLE.

Adult↗
PubMed1984

Systemic suppression of contact hypersensitivity by ultraviolet b radiation or methoxsalen/ultraviolet a radiation in the guinea pig.

Treatment of strain 2 guinea pigs with ultraviolet b (uvb) (280-320 nm) radiation or methoxsalen, followed by ultraviolet a (uva) (320-400 nm) radiation, decreased the contact hypersensitivity (CHS) reaction to sensitizing agents applied subsequently to unirradiated sites. The decreased reactivity could be transferred to syngeneic animals and appeared to be caused by antigen-specific suppressor T lymphocytes. Ultraviolet b irradiation of sensitized animals did not affect elicitation of CHS in unirradiated skin.

Animals↗
PubMed1984

Spectral power distributions of radiation sources used in phototherapy and photochemotherapy.

Much attention is focused on the amount of radiant energy emitted by treatment systems used in phototherapy and photochemotherapy; however, another important property of a radiation source, the spectral power distribution (SPD), has often been ignored. Measurement of the SPDs of various radiation sources produced unexpected findings. The SPDs of fluorescent bulbs promoted specifically for use in psoralen and ultraviolet A (PUVA) therapy was fairly uniform. However, of three blacklight bulbs that also may be used for PUVA therapy, each had a different SPD, and one of these bulbs emitted more than 90% of its energy in the ultraviolet (UV) wave band at wavelengths greater than 360 nm. The wavelengths emitted by sunlamp fluorescent bulbs and an Alpine UV lamp, both of which are used for phototherapy, were predominantly less than 320 nm. A fluorescent bulb recently introduced for phototherapy had an SPD that was different from that of a PUVA bulb and from that of a sunlamp bulb, with a high emission in the 300- to 340-nm wave band. These findings indicate that consideration of both the SPD and the irradiance of a radiation source is necessary to determine its suitability for phototherapy or photochemotherapy.

Photochemotherapy↗
PubMed1984

The effect of a sunscreen containing para-aminobenzoic acid on the systemic immunologic alterations induced in mice by exposure to UVB radiation.

Application of a sunscreen containing para-aminobenzoic acid partially abrogated certain of the systemic immunologic alterations produced in mice by exposure to UVB (280-320 nm) radiation from sunlamp bulbs. The sunscreen reduced the degree of UVB-induced suppression of contact hypersensitivity to a chemical applied subsequently to nonirradiated skin. In addition, it reduced the frequency with which mice became susceptible to the growth of a highly antigenic, syngeneic, UVB-induced tumor following chronic treatment with UVB radiation, but this effect was not statistically significant. The tumor-susceptible state was transferred from animals treated with sunscreen and UVB radiation to lethally x-irradiated mice by injection of spleen cells. The gross morphology of the skin of mice treated with sunscreen and UVB radiation was normal but the histologic changes induced by UVB irradiation in skin were only partially abrogated by the sunscreen.

4-Aminobenzoic Acid↗
PubMed1984

Photoimmunology.

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Animals↗
PubMed1984

In vivo effects of psoralens plus longwave ultraviolet radiation on immunity.

Treatment with 8-methoxypsoralen plus UV radiation at 320-400 nm (PUVA) alters immune function in experimental animals and humans. In guinea pigs, the treatment can suppress the development of delayed hypersensitivity to an injected antigen and the development of contact hypersensitivity locally at the site of exposure to radiation and systemically at a nonexposed site. The mechanisms of these changes are unknown but may involve certain alterations that occur after treatment in Langerhans cells. In normal human subjects, PUVA treatment can alter the distribution of circulating T- and B-lymphocytes, and this effect appears to be dose related. The distribution and function of T-lymphocytes in patients with psoriasis are also altered by PUVA treatment. These effects are greater with high, cumulative exposure doses of the treatment. Suppression of contact hypersensitivity also has been observed in patients with mycosis fungoides and psoriasis treated with PUVA. Autoimmune phenomena do not appear to be a side effect of the treatment. Although immunosuppression may be a mechanism of action by which PUVA treatment exerts its therapeutic effect on disease, it can also result in adverse effects after long-term treatment.

Animals↗