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To determine the effect of different fixatives on the recovery and detection of mRNAs from archival histopathology specimens, biopsies of normal skin were fixed in neutral and alcohol-buffered formalin, acetone, Carnoy's fixative, methacarn, and Bouin's solution. Tissue was routinely processed, and sections were either mounted for in situ hybridization or deparaffinized for RNA extraction. Extracted mRNA was reverse-transcribed using random hexamers, and the resulting cDNA was amplified by the polymerase chain reaction using primers specific for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and beta-actin. Amplification products of both GAPDH and actin could be detected by gel electrophoresis from tissues processed in all fixatives except Bouin's. A parallel study of formalin-fixed, paraffin-embedded archival biopsies accessioned since 1990 gave similar results. Less abundant mRNAs, such as those encoding interleukin-11 or the T-cell receptor beta-chain, could be detected by Southern blotting and hybridization with labeled oligonucleotide probes or by cloning and sequencing. In situ hybridization studies using oligonucleotide probes were most successful with tissue fixed in formalin, including both the experimentally fixed tissues and the archival biopsy samples. Thus, mRNAs may be isolated from and localized in formalin-fixed, paraffin-embedded archival material. Because dermatopathology laboratory archives typically contain samples from a wide spectrum of diseases that can be accessed without Human Investigation Committee approval, these laboratories represent a logical starting point for studying gene regulation and expression in skin.

Voluntary daytime headlight use by the majority of motorcyclists might endanger those not using lights: it has been suggested that drivers might scan for lights rather than for motorcyclists per se. Two experiments are described that attempted to investigate this issue in the laboratory. Subjects had to decide as rapidly as possible whether or not a motorcyclist was present in each of a series of slides depicting traffic. Experiment 1 showed that headlight-using motorcyclists were more quickly detected than unlit motorcyclists, especially when they were far away. However, repeated exposure to headlight-using motorcyclists significantly delayed detection of an unlit motorcyclist. Experiment 2 showed that this delayed-detection effect occurred when only 60% of the motorcyclists shown were using their headlight. Under laboratory conditions, at least, subjects readily appear to develop a 'set' for responding on the basis of headlight-use, even when this is an unreliable guide to the motorcyclists' presence.

Cutaneous T-cell lymphoma (CTCL) is a malignancy of mature T lymphocytes, most of which express alpha/beta type T-cell receptors (TCRs). The cause of CTCL is unknown, but hypotheses postulating chronic stimulation of TCRs by superantigen or by a leukemogenic virus have been proposed. Either mechanism might produce bias in the TCR variable (V) region types used by the malignant cells. To determine if TCR alpha use is restricted in CTCL, we used reverse transcription and the polymerase chain reaction to determine V alpha and V beta usage by malignant cells purified from the peripheral blood of leukemic patients with CTCL. Usage of alpha chain V region segments appeared totally random; malignant lymphocytes isolated from each of six patients used different V alpha regions. As has been previously reported, no bias was found in beta chain V region usage either. In addition to productive (in frame) TCR V region mRNAs in malignant cells from each patient, we detected non-productive (out of frame) beta chain transcripts in these cells in two of six patients, and non-productive alpha chain transcripts in five of six. Residual normal peripheral blood lymphocytes from these patients showed a random, polyclonal or oligoclonal pattern of V region usage. We conclude that there is no bias in V region usage in CTCL, making it unlikely that interactions between superantigen or virus and the TCR V regions play a role in the pathogenesis of CTCL.

Background and Methods: The lesions of cutaneous mastocytosis are characterized by dermal infiltrates of mast cells and may appear hyperpigmented because of the presence of increased levels of epidermal melanin. Mast-cell growth factor, the ligand for the product of the c-kit proto-oncogene, stimulates the proliferation of mast cells and increases the production of melanin by melanocytes. We therefore looked for the expression of the mast-cell growth factor gene in the skin of patients with cutaneous mastocytosis using immunohistochemical techniques and the polymerase chain reaction., Results: In the skin of normal subjects and those with unrelated diseases, immunoreactive mast-cell growth factor was associated with keratinocytes and scattered dermal cells, a pattern consistent with cell-bound mast-cell growth factor. In skin samples containing lesions and in clinically normal skin from patients with mastocytosis, however, mast-cell growth factor was also found free in the dermis and in the extracellular spaces between keratinocytes, suggesting the presence of a soluble form of this protein. Messenger RNA (mRNA) that can encode soluble mast-cell growth factor was present in the skin of patients as well as in that of normal control subjects. No sequence abnormalities were detected in mRNA for mast-cell growth factor from one patient., Conclusions: The altered distribution of mast-cell growth factor in the skin of patients with cutaneous mastocytosis is consistent with abnormal production of the soluble form of this factor. This abnormality is probably due to increased proteolytic processing, since it was not explained by differences in the splicing or sequence of mast-cell growth factor mRNA in the patients. Soluble mast-cell growth factor may cause the characteristic accumulation of mast cells and the hyperpigmentation of skin found in cutaneous mastocytosis. These findings suggest that some forms of mastocytosis represent reactive hyperplasia rather than mast-cell neoplasia.

Treatment for recurrent genital herpes using edoxudine 3% cream for 5 days was evaluated in 200 patients in a randomized, multicenter, double-blind, placebo-controlled, clinic-initiated trial. Lesion tenderness was predictive of and more sensitive and longer-lasting than the symptom of pain. Among patients receiving placebo, times to crusting (P = .043), cessation of investigator-observed signs (P = .005), lesion-associated signs (P = .02), and groin signs (P = .05) were longer in women. Edoxudine reduced viral shedding in men (mean 2.7 vs. 3.4 days, P = .009) and women (2.0 days vs. 3.5 days, P = .0001). Loss of investigator-observed signs (4.4 vs. 6.2 days, P = .002), investigator-observed lesion tenderness (P = .01), lesion signs (P = .02), groin adenopathy (P = .01), and tenderness (P = .01) occurred earlier in women taking edoxudine. Edoxudine was well-tolerated and reduced several signs of herpes in women. Its clinical role in recurrent genital herpes remains to be fully determined.