Biomedical subjects
Publications and source records attributed to M B Poh-Fitzpatrick.
Reactivation of a sunburn has been reported after the administration of methotrexate for cancer chemotherapy. A similar reaction is described in a patient with psoriasis who was receiving both coal tar with ultraviolet radiation for cutaneous lesions and methotrexate for arthritis. Knowledge of this poorly understood side effect of methotrexate is particularly important for physicians administering phototherapy and, perhaps, photochemotherapy.
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Variegate porphyria (VP) is a rare disease infrequently diagnosed in the United States. The typical cutaneous signs of VP, including fragility, bullae, scarring, hypertrichosis, and photosensitivity, are indistinguishable from those of porphyria cutanea tarda (PCT). Inadequate laboratory evaluation of porphyrins present in, or improper interpretation of porphyrin test results from, biologic specimens from patients with VP may lead to inappropriate diagnosis and treatment. Clinical and laboratory data for three such cases of VP are presented. A plasma porphyrin fluorescence criterion which appears specific for patients with VP was observed in all three cases.
A fourth case of symptomatic porphyria associated with hemodialysis for chronic renal failure is reported. Subepidermal bullous dermatoses of patients who have undergone hemodialysis have not usually been associated with elevated porphyrin levels. However, this patient and three previously reported cases have been found to have abnormal porphyrin study results in association with skin lesions typical for porphyria cutanea tarda, occurring after hemodialysis. Hemodialysis does not effectively decrease circulating plasma uroporphyrin levels, although some dialysis of uroporphyrin into the dialysate could be measured in this case. Evaluation of bullous or porphyrialike dermatoses in patients treated with hemodialysis should include adequate testing for increased porphyrin levels.
Ten patients with variegate porphyria were uniformly found to have distinctive plasma porphyrin fluorescence wavelength maxima in saline-diluted plasma specimens. The porphyrin complex in each of these plasma samples had a fluorescence emission maximum at 626 +/- 1 nm. Twelve patients with porphyria cutanea tarda, eight patients with erythropoietic protoporphyria, one patient with congenital erythropoietic porphyria, two patients with acute intermittent porphyria, and four patients with hereditary coproporphyria, whose plasma specimens were similarly examined, had plasma fluorescence characteristics that were different from those of the patients with variegate porphyria. Plasma fluorescence emission that is maximal at 626 +/- 1 nm is a diagnostic marker for variegate porphyria.
Human protoporphyria with atypical features suggesting increased hepatic protoporphyrin synthesis was investigated in 2 patients. Analysis of the distribution of protoporphyrin among circulating erythrocytes of increasing age indicated that the erythrocyte porphyrin burden derived predominantly from erythroid sources in case 1, and from hepatic sources in case 2. Intravenous hematin was administered to both patients to assess any negative feedback effect on protoporphyrin synthesis. Erythrocyte, fecal and plasma porphyrin levels were measured serially during basal, treatment, and follow-up periods. In case 1, a significant (P less than 0.001) drop in both fecal and plasma levels accompanied hematin, while erythrocyte levels remained unchanged. Hematin produced no appreciable changes in porphyrin concentrations in case 2. Allergic vasculitis followed hematin use in both cases. Based on data of this study and on previous data, a model for protoporphyrin transport and clearance was developed in which the variable clinical and biochemical manifestations of human protoporphyria are related to the relative contributions of erythroid and hepatic sources to the abnormal protoporphyrin pools.
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We have demonstrated in this study that mitogen-stimulated lymphocytes from EPP subjects accumulate substantially greater amounts of protoporphyrin IX than do normal lymphocytes when incubated with ALA. Protoporphyrin IX formation by normal lymphocytes is stimulated by CaMgEDTA, an inhibitor of ferrochelatase, and is decreased by ferrous iron which facilitates the utilization of protoporphyrin IX for heme synthesis. In contrast, protoporphyrin IX formation by EPP lymphocytes is less stimulated by CaMgEDTA than is the case with normal lymphocytes and is only slightly affected by iron. Clinically manifested EPP subjects and completely latent gene carriers of EPP can be identified using this lymphocyte culture technique. The data from this study provide clear evidence of a functional deficiency of ferrochelatase activity in human EPP lymphocytes. EPP thus represents the third of the three dominant porphyric disorders of man, including acute intermittent porphyria and hereditary coproporphyria, which can now be diagnosed using lymphocytes.
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Pyoderma gangrenosum (PG) has been increasingly reported in association with myeloproliferative disorders. Monoclonal gammaopathy, myeloma, myeloid metaplasia, and polycythemia have all been found in association with PG. Recently, seven cases of PG in association with leukemia have been described: three cases with acute myeloblastic leukemia, two cases with chronic myelogenous leukemia, one case with acute lymphoblastic leukemia, and one case with acute leukemia of either plasma cell or myeloblast origin. To these we add two cases of PG with acute myeloblastic leukemia. These patients often have an atypical clinical presentation for PG, with bullae and relatively superficial involvement obscuring the correct diagnosis.
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Porphyrin production by Propionibacterium acnes and that by Propionibacterium granulosum were compared. Porphyrin synthesized by both organisms was identified as coproporphyrin III on the bases of absorption and fluorescence spectra and behavior on paper chromatography and thin-layer chromatography. Quantitative, rather than qualitative, differences in production were found between these organisms. In general, P. granulosum produced significantly greater amounts (P less than 0.001) of porphyrin than did P. acnes. delta-Aminolevulinic acid synthetase appeared to be the rate-limiting enzyme of the heme biosynthetic pathway in both organisms. The increased porphyrin production in P. granulosum is apparently associated with increased delta-aminolevulinic acid synthetase activity.
Two patients with hydroa vacciniforme, a rare photodermatosis of unknown etiology, demonstrated distinctive scarring and vesiculobullous skin lesions on light-exposed body areas. Results of blood and urine porphyrin studies were normal, and no systemic abnormalities were noted. A small bullous lesion was produced in normal skin in case 1 with 15 times the minimal erythema dose of ultraviolet energy. The conditions of both patients improved while they were taking beta carotene orally.