Clinicopathologic and immunophenotypic characterization of lichen planopilaris and central centrifugal cicatricial alopecia: A comparative study of 51 cases

BACKGROUND

The purpose of the study was to compare the histopathologic and immunophenotypic features of central centrifugal cicatricial alopecia (CCCA) and lichen planopilaris (LPP) to better characterize and differentiate these two clinical entities. CCCA remains an ill-defined and still-unsettled histologic entity and many hair loss experts regard CCCA to be histologically indistinguishable from LPP. Given the overlapping histologic features of these two lymphocyte-predominant cicatricial alopecias, and the lack of consensus regarding the significance of proposed distinctions, dermatopathologists face difficulty in providing clinicians and patients certainty with a definitive diagnosis of CCCA vs LPP.

METHODS

We performed a retrospective review of 51 scalp biopsies of patients with either the clinical diagnosis of CCCA (27 cases) or LPP (24 cases). Clinical information, histologic features of hematoxylin-eosin-stained sections, and a panel of immunohistochemical markers were evaluated on scalp biopsies. Tested parameters were quantified, and statistical analysis was performed.

RESULTS

Our study found no differences on either histologic assessment or immunophenotypic characterization between cases of classic LPP and CCCA.

CONCLUSION

The conclusion of this study is that the inflammatory infiltrates in CCCA and LPP are not only histologically similar but also immunophenotypically indistinguishable.

Control of helicase loading in the coupled DNA replication and recombination systems of bacteriophage T4

The Gp59 protein of bacteriophage T4 promotes DNA replication by loading the replicative helicase, Gp41, onto replication forks and recombination intermediates. Gp59 also blocks DNA synthesis by Gp43 polymerase until Gp41 is loaded, ensuring that synthesis is tightly coupled to unwinding. The distinct polymerase blocking and helicase loading activities of Gp59 likely involve different binding interactions with DNA and protein partners. Here, we investigate how interactions of Gp59 with DNA and Gp32, the T4 single-stranded DNA (ssDNA)-binding protein, are related to these activities. A previously characterized mutant, Gp59-I87A, exhibits markedly reduced affinity for ssDNA and pseudo-fork DNA substrates. We demonstrate that on Gp32-covered ssDNA, the DNA binding defect of Gp59-I87A is not detrimental to helicase loading and translocation. In contrast, on pseudo-fork DNA the I87A mutation is detrimental to helicase loading and unwinding in the presence or absence of Gp32. Other results indicate that Gp32 binding to lagging strand ssDNA relieves the blockage of Gp43 polymerase activity by Gp59, whereas the inhibition of Gp43 exonuclease activity is maintained. Our findings suggest that Gp59-Gp32 and Gp59-DNA interactions perform separate but complementary roles in T4 DNA metabolism; Gp59-Gp32 interactions are needed to load Gp41 onto D-loops, and other nucleoprotein structures containing clusters of Gp32. Gp59-DNA interactions are needed to load Gp41 onto nascent or collapsed replication forks lacking clusters of Gp32 and to coordinate bidirectional replication from T4 origins. The dual functionalities of Gp59 allow it to promote the initiation or re-start of DNA replication from a wide variety of recombination and replication intermediates.

Self-reports of HIV risk factors by patients at a sexually transmitted disease clinic: audio vs written questionnaires

OBJECTIVES

The purpose of this study was to determine how the method of assessment affects patient report of human immunodeficiency virus (HIV) risks.

METHODS

Patients at a sexually transmitted disease clinic randomly received either a written self-administered questionnaire or an audio self-administered questionnaire delivered by cassette player and headset. These questionnaires were followed by face-to-face interviews.

RESULTS

Audio questionnaires had fewer missing responses than written questionnaires. Audio questionnaires also identified more unprotected vaginal intercourse and sexual partners suspected or known to have HIV infection or acquired immunodeficiency syndrome than did written questionnaires. Although both the audio and written questionnaires identified more risks than the face-to-face interviews, the difference in the mean number of reported risks between the audio questionnaires and the face-to-face interviews was greater than that between the written questionnaires and the face-to-face interviews.

CONCLUSIONS

Audio questionnaires may obtain more complete data and identify more HIV risk than written questionnaires. Research is warranted about whether audio questionnaires overcome barriers to the completion and accuracy of HIV risk surveys. This study emphasizes the need to elucidate the relative strengths and weaknesses of written questionnaires, audio questionnaires, and face-to-face interviews for HIV risk assessment.