Analysis of complement and plasma cells in the brain of patients with anti-NMDAR encephalitis.

OBJECTIVES: Most patients with anti-NMDA receptor (NMDAR) encephalitis have intrathecal synthesis of antibodies, which cause a decrease of cell surface and synaptic NMDAR. Antibodies are immunoglobulin G (IgG)1 and IgG3 subtypes and can potentially activate complement. We examined whether complement immunoreactivity and antibody-secreting cells (plasma cells/plasmablasts) are present in the brain of these patients. METHODS: Cultured rat hippocampal neurons were used in an immunocytochemical assay to test whether patients' antibodies can fix complement. Using the same reagents (antibodies to C9neo, C(5b-9), C3), complement immunoreactivity was determined in the brain of 5 patients, the teratoma of 21 patients, and appropriate control tissues. A set of markers for B (CD20), T (CD3, CD4, CD8) and antibody-secreting cells (plasma cells/plasmablasts, CD138) were used to examine the brain inflammatory infiltrates. RESULTS: Patients' antibodies were able to bind complement in vitro, but deposits of complement were not detected in patients' brain. Parallel experiments with teratomas showed that in contrast to the brain, the neural tissue of the tumors contained complement. Analysis of the inflammatory infiltrates in brain samples from autopsy or biopsy performed 3-4 weeks after symptom presentation demonstrated numerous antibody-secreting cells (CD138+) in perivascular, interstitial, and Virchow-Robin spaces, and B and T cells predominantly located in perivascular regions. CONCLUSIONS: Complement-mediated mechanisms do not appear to play a substantial pathogenic role in anti-NMDAR encephalitis. In contrast, there are copious infiltrates of antibody-secreting cells (plasma cells/plasmablasts) in the CNS of these patients. The demonstration of these cells provides an explanation for the intrathecal synthesis of antibodies and has implications for treatment.

A topical azithromycin preparation for the treatment of acne vulgaris and rosacea.

BACKGROUND: Erythromycin is a common therapy for acne and rosacea. A newer macrolide, azithromycin, offers superior tissue distribution and cellular concentration and is an effective oral anti-acne agent. Topical formulations such as erythromycin have been a major clinical therapy for acne. To date, no topical solution of azithromycin is available for the treatment of acne. OBJECTIVE: To prepare a stable topical 2% azithromycin formulation that could be used in an acne clinical trial to determine the efficacy of topical azithromycin in treating subjects with acne vulgaris and acne rosacea. METHODS: The study was divided into two phases. In phase I, azithromycin was prepared over a range of ethanol/water concentrations to determine solubility. The stability of a 2% azithromycin in 60% ethanol/water preparation was assessed by high-pressure liquid chromatography. The temperature, light, and pH dependence of the stability was also assessed. In phase II, a single center, randomized, double-blind, treatment-controlled study compared once-nightly application of topical 2% azithromycin versus 2% erythromycin. A total of 20 subjects with moderate inflammatory acne and 20 with rosacea were examined clinically at 0, 2, 4, 8, and 12 weeks for a 12-week period. Efficacy was evaluated with the Physician's Visual Analog Scale evaluation (PVAS), the papulopustule count, and acne severity rating (in subjects with acne). RESULTS: In phase I, azithromycin was soluble in 60% ethanol/water. A 2% azithromycin in 60% ethanol/water solution maintained stability at room temperature for up to 26 weeks but at 37 degrees C there was some decay (16%) at 26 weeks. The stability was greatest at pH 6.8 and was unaffected by ambient light exposure. In phase II, the number of inflammatory lesions decreased in both acne and rosacea subjects treated with 2% erythromycin (7.56, p=0.03 and 4.4, p=0.01, respectively). Azithromycin was not as effective for the treatment of rosacea. Both azithromycin (p=0.01) and erythromycin (p=0.03) treatment significantly reduced the inflammatory lesion count in acne vulgaris. No significant adverse events were identified in the acne group. In patients with rosacea, transient irritation occurred in five patients. CONCLUSIONS: A 2% azithromycin in 60% ethanol/water solution can be prepared and is stable for at least 6 months at room temperature. The methodology and power of the study were adequate to identify improvement in acne vulgaris and rosacea. Though it appears the formulation of topical azithromycin was at least comparable with topical erythromycin, larger studies would be needed to determine whether topical azithromycin has any significant advantage over topical erythromycin.

Expression of microtubule-associated protein 2 in benign and malignant melanocytes: implications for differentiation and progression of cutaneous melanoma.

Cutaneous melanocytic neoplasms are known to acquire variable characteristics of neural crest differentiation. Melanocytic nevus cells in the dermis and desmoplastic melanomas often display characteristics of nerve sheath differentiation. The extent and nature of neuronal differentiation characteristics displayed by primary and metastatic melanoma cells are not well understood. Here, we describe induction of a juvenile isoform of microtubule-associated protein 2 (MAP-2c) in cultured metastatic melanoma cells by the differentiation inducer hexamethylene bisacetamide. Up-regulation of this MAP-2 isoform, a marker for immature neurons, is accompanied by extended dendritic morphology and down-regulation of tyrosinase-related protein 1 (TYRP1/gp75), a melanocyte differentiation marker. In a panel of cell lines that represent melanoma tumor progression, MAP-2c mRNA and the corresponding approximately 70-kd protein could be detected predominantly in primary melanomas. Immunohistochemical analysis of 61 benign and malignant melanocytic lesions showed abundant expression of MAP-2 protein in melanocytic nevi and in the in situ and invasive components of primary melanoma, but only focal heterogeneous expression in a few metastatic melanomas. In contrast, MAP-2-positive dermal nevus cells and the invasive cells of primary melanomas were TYRP1-negative. This reciprocal staining pattern in vivo is similar to the in vitro observation that induction of the neuronal marker MAP-2 in metastatic melanoma cells is accompanied by selective extinction of the melanocytic marker TYRP1. Our data show that neoplastic melanocytes, particularly at early stages, retain the plasticity to express the neuron-specific marker MAP-2. These observations are consistent with the premise that both benign and malignant melanocytes in the dermis can express markers of neuronal differentiation.

Topical corticosteroid in foam vehicle offers comparable coverage compared with traditional vehicles.

BACKGROUND: A new preparation of betamethasone valerate in a novel foam vehicle is available for treatment of scalp dermatoses. The vehicle spreads between hair until it reaches the scalp, where it melts and delivers the active drug. Solids make up only a tiny fraction of the foam vehicle, leaving no apparent residue on the skin or hair. The uniqueness of this vehicle raises the question of how to compare it with other topical corticosteroid preparations. OBJECTIVE: The purpose of this study was to determine the equivalency of a given quantity of the foam product to quantities of drugs in conventional vehicles. METHODS: The number of fingertip units (FTUs) per gram and the area of coverage of an FTU of betamethasone valerate foam vehicle were determined and compared with those of cream, lotion, gel, and solution psoriasis treatments. RESULTS: The weight of an FTU of foam vehicle was 52.5 +/- 5.7 microg. There were 9 to 12 times as many FTUs in 100 g of vehicle foam as in 100 g of cream or gel and 2.3 to 2.8 times as many as in 100 g of lotion or solution. The area covered by an FTU of foam vehicle was less than the area covered by an FTU of cream or gel. CONCLUSION: The characteristics of foam vehicle are different from those of other vehicles. The greater number of FTUs in 100 g of foam vehicle made up for the lower coverage per FTU, such that total coverage area for 100 g of foam vehicle was comparable to the coverage area for 100 g of the drugs in traditional vehicles.

Importance of the carboxyl terminus in the folding and function of alpha-hemolysin of Staphylococcus aureus.

The physical state of two model mutants of alpha-hemolysin (alphaHL), alphaHL(1-289), a carboxyl-terminal deletion mutant (CDM), and alphaHL(1-331), a carboxyl-terminal extension mutant (CEM), were examined in detail to identify the role of the carboxyl terminus in the folding and function of native alphaHL. Denatured alphaHL can be refolded efficiently with nearly total recovery of its activity upon restoration of nondenaturing conditions. Various biophysical and biochemical studies on the three proteins have revealed the importance of an intact carboxyl terminus in the folding of alphaHL. The CDM exhibits a marked increase in susceptibility to proteases as compared with alphaHL. alphaHL and CEM exhibit similar fluorescence emission maxima, and that of the CDM is red-shifted by 9 nm, which indicates a greater solvent exposure of the tryptophan residues of the CDM. In addition, the CDM binds 8-anilino-1-naphthalene sulfonic acid (ANS) and increases its fluorescence intensity significantly unlike alphaHL and CEM, which show marginal binding. The circular dichroism studies point that the CDM possesses significant secondary structure, but its tertiary structure is greatly diminished as compared with alphaHL. These data show that the CDM has several of the features that characterize a molten globule state. Experiments with freshly translated mutants, using coupled in vitro transcription and translation, have further supported our observations that deletion at the carboxyl terminus leads to major structural perturbations in the water-soluble form of alphaHL. The studies demonstrate a critical role of the carboxyl terminus of alphaHL in attaining the native folded state.

Epidermal stratification reduces the effects of UVB (but not UVA) on keratinocyte cytokine production and cytotoxicity.

Ultraviolet (UV) radiation induces cytokine release from cultured keratinocytes as well as from epidermis in vivo. The purpose of this study was to determine whether differentiation of cultured keratinocytes into stratified epithelium decreases the effects of UVA and UVB radiation on cytokine release. Interleukin-1 (IL-1) alpha, IL-1 beta and tumor necrosis factor (TNF)-alpha release from human keratinocytes and reconstituted human epidermis was measured after exposure to UVA or UVB radiation. Release of IL-1 alpha, IL-1 beta, and TNF-alpha was induced by both UVA and UVB radiation from both keratinocytes and reconstituted epidermis. Release of these cytokines was correlated with cytotoxicity. Keratinocyte cultures were far more sensitive to UVB radiation than reconstituted epidermis, in terms of both cytotoxicity and cytokine release. In contrast, epidermal stratification/differentiation had much less effect on the sensitivity to UVA radiation. We conclude that epidermal stratification and the formation of a stratum corneum provide protection against UVB radiation but have limited barrier effect against UVA radiation.

Immunohistochemical localization of alpha 2-macroglobulin receptors in human skin.

The localization of receptors for the proteinase inhibitor alpha 2-macroglobulin was studied in human skin by immunohistochemistry using a monoclonal mouse antibody. No epidermal staining was identified. alpha 2-Macroglobulin receptors were identified on dermal fibroblasts and dermal dendritic cells. Endothelial cells did not stain with the antibody, but positive staining cells were concentrated around dermal vessels. The myoepithelial layer of eccrine glands exhibited receptors; however, there was no staining of the eccrine epithelial layer. The distribution of alpha 2-macroglobulin receptors correlates with the reported distribution of alpha 2-macroglobulin: both are present in the dermal connective tissue and absent in epithelium and endothelium. The distribution of alpha 2-macroglobulin and its receptor in the dermis is consistent with a possible role in regulation of dermal proteolytic activity.