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Biomedical subjects

H W Lim

Publications and source records attributed to H W Lim.

118 records · Page 7Linked to original sources
PubMed1982

Effect of glucocorticosteroids on epidermal Langerhans cells.

The effects of topical and systemic administration of various glucocorticoids on the density of epidermal Langerhans cells (LC) were studied in guinea pigs. Glucocorticoids, such as betamethasone dipropionate and valerate, caused a marked decrease in LC demonstrable by staining for cell membrane ATPase activity and Ia antigens. By electronmicroscopy, LC also showed morphologic alterations. The observed decrements in LC density correlated with the concentration and known vasoconstrictive potency of the glucocorticoids administered. The anti-inflammatory action of glucocorticoids in skin disorders may, at least in part, be through their ability to alter epidermal LC, thus interfering with the antigen-presenting functions of these cells.

Adenosine Triphosphatases↗
PubMed1981

Role of complement in porphyrin-induced photosensitivity.

Addition of porphyrins to sera of guinea pigs in vitro, followed by irradiation with 405 nm light, resulted in dose-dependent inhibitions of hemolytic activity of complement (CH50, C3, and C5). With guinea pig as an animal model, we also found that systemically administered porphyrins, followed by irradiation with 405 nm light, resulted in dose-dependent inhibition of CH50 in vivo. The erythrocytes from porphyrin-treated guinea pigs showed an increased susceptibility to hemolysis induced by 405 nm irradiation in vitro. Clinical changes in these animals were limited to light-exposed areas and consisted of erythema, crusting, and delayed growth of hair. Histologically, dermal edema, dilation of blood vessels, and infiltration of mononuclear and polymorphonuclear cells were observed. Guinea pigs irradiated with ultraviolet-B developed erythema, but had no alteration of their complement profiles. It is suggested that complement products may play a specific role in the pathogenesis of the cutaneous lesions of some porphyrias.

Animals↗
PubMed1981

Complement-derived chemotactic activity is generated in human serum containing uroporphyrin after irradiation with 405 nm light.

Patients with porphyrias have varying degrees of photosensitivity, associated with elevated levels of porphyrins in plasma, erythrocyte, urine and/or feces. To investigate the role of complement in the pathogenesis of cutaneous lesions, varying amounts of uroporphyrin were added to normal human serum (0.1-10 microgram/ml), and the mixtures were then exposed to 405 nm irradiation. Such treatments result in the diminution of total hemolytic complement activity and hemolytic titers of C1, C4, C2, C3, and C5; furthermore, cleavage products of C3 and C5 were detected. Chemotactic activity for human polymorphonuclear leukocytes was generated that was inhibitable by incubation with anti-C5, but not with anti-C3 antisera. No chemotactic activity was generated in Mg++-EGTA treated serum nor in C4-deficient guinea pig serum. These data indicate that irradiation with 405 nm light of normal human serum containing uroporphyrin results in activation of the complement system via the classical pathway, and the generation of complement (C5)-derived chemotactic activity for human polymorphonuclear leukocytes.

Adult↗
PubMed1978

Postsurgical, chronic, nonprogressive, cutaneous ulcers: a possible variant of pyoderma gangrenosum associated with diabetes mellitus.

Two patients developed persistent ulcers on the trunk after cutaneous surgery. Both had "chemical" diabetes mellitus. Bacteriologic and histopathologic studies of the ulcers were not revealing of cause. The characteristics of the ulcers are described, and are contrasted with typical lesions of pyoderma gangrenosum and Meleney's postoperative progressive synergistic bacterial gangrene. We believe these patients had variant lesions of pyoderma gangrenosum.

Adolescent↗
PubMedDate not supplied

The porphyrias.

Explore the source record for details and available documents.

Female↗
PubMedDate not supplied

Skin response to ultraviolet B light in patients infected with human immunodeficiency virus.

Photosensitivity disorders have been reported in human immunodeficiency virus (HIV)-infected patients, often as the initial manifestation of the disease. The objective of this study was to evaluate whether the HIV-infected population demonstrates increased sensitivity to ultraviolet B (UVB) radiation. Minimal erythema dose values to UVB (MED-B) of 57 consecutive HIV-infected patients were compared to those of a control group of 57 consecutive patients with skin diseases, who were otherwise healthy and had no risk factors for HIV infection. MED-B determinations were performed in all individuals prior to the initiation of phototherapy for treatment of skin disease. None of the patients had a history of photosensitivity. Furthermore, the mean levels of the highest UVB doses received by each group during the treatment courses were compared. The mean age of the HIV-infected cohort was 43 years (range 26-61 years). The mean MED-B for this group was 82.8 +/- 3.8 (SEM) mJ/cm2. The mean age of the control group was 45 years (range 24-77 years), and their mean MED-B was 81.0 +/- 3.8 (SEM) mJ/cm2. After 12 weeks of treatment, one HIV-infected patient developed photosensitivity associated with a decreased MED-B value. The mean level of the highest UVB doses received by the HIV-infected group [427.5 +/- 67.2 (SEM) mJ/cm2] was lower than that received by the control group [640.8 +/- 65.9 (SEM) mJ/cm2], since HIV-infected patients received fewer treatments (mean: 34.7 treatments per patient) than the patients in the control group (mean: 65.6 treatments per patient). These data indicate that the HIV-infected patient population, without history of photosensitivity, does not show increased sensitivity to UVB light as determined by MED-B values.

Adult↗
PubMedDate not supplied

Photosensitivity disease: pathophysiology and management.

The clinical manifestations, pathophysiology, and treatment of the following common photosensitivity diseases are reviewed in this article: polymorphous light eruption, solar urticaria, drug-induced photodermatoses, chronic actinic dermatitis, porphyria cutanea tarda, and erythropoietic protoporphyria.

Humans↗