Hair follicles (HFs) undergo life-long cyclical transformations, progressing through stages of rapid growth (anagen), regression (catagen), and relative “quiescence” (telogen). Since HF cycling abnormalities underlie many human hair growth disorders, the accurate classification of individual cycle stages within skin biopsies is clinically important and essential for hair research. For preclinical human hair research purposes, human scalp skin can be xenografted onto immunocompromised mice to study human HF cycling and manipulate long-lasting anagen in vivo. While available for mice, a comprehensive guide on how to recognize different human hair cycle stages in vivo is lacking. Here, we present such a guide, which uses objective, well-defined, and reproducible criteria and integrates simple morphological indicators with advanced, (immuno)-histochemical markers. This guide also characterizes human HF cycling in xenografts and highlights the utility of this model for in vivo hair research. Detailed schematic drawings and representative micrographs provide examples of how best to identify human HF stages, even in sub-optimally sectioned tissue, and practical recommendations are given for designing human-on-mouse hair cycle experiments. Thus, this guide seeks to offer a benchmark for human hair cycle stage classification, for both hair research experts and newcomers to the field.

Background: Generalized granuloma annulare (GGA) is a benign skin disorder of an unknown etiology. Though some cases of GGA have been reported, few systemic reviews of the clinical and pathological features of GGA have been performed. Objective: The purpose of this study is to analyze and correlate the clinical and pathological characteristics of GGA in Korean patients. Methods: We conducted a retrospective study that included 54 biopsy specimens of Korean GGA patients, and the clinical and pathological features of GGA were reviewed and analyzed for their correlation. Results: The cutaneous lesions could be divided into the annular (24, 44%) and nonannular types (30, 56%), and the lesions were more common in males than in females (29 males and 25 females). The incidence of GGA showed a bimodal age distribution. The number of patients who presented within the first decade was 24 cases (44%), and 24 cases (44%) were over the fifth decade. Eight patients (15%) had systemic diseases. Especially, diabetes mellitus (DM) occurred only in the adult GGA patients over forty years old. The pathological findings showed dermal granulomatous lesions that consisted of either a palisading pattern (28, 52%) or an interstitial pattern (26, 48%). Conclusion: In contrast to the previously reported studies, the age of GGA onset showed a bimodal distribution, and GGA was observed more often in males. The prevalence of DM in the GGA affected individuals was higher than that found in the general Korean population. Therefore, it is recommended to perform a work-up for DM in the GGA affected patients who are over forty years old. (Ann Dermatol 21(2) 113∼119, 2009)

A blue phosphorescent iridium(III) complex (1) bearing fluorine-substituted bipyridine (dfpypy) has been synthesized and characterized to investigate the effect of the substitution and replacement of the phenyl ring in ppy (phenylpyridine) with pyridine on the solid state structure and its photoluminescence. The optical properties and electrochemical behaviors of 1 have also been systematically evaluated. The structure of 1 has also been determined by a single-crystal X-ray diffraction analysis. There are varied intermolecular interactions caused by the pyridine and fluorine substituents, such as C-H...N, C-H...F, and pi...pi interactions of either face-to-face type or edge-to-face C-H...pi and halogen...pi in crystal packing. In electrochemistry, the remarkably higher oxidation potential than that of FIrpic was observed. The emission lambda(max) of 1 at room temperature is at 438 nm with a higher PL quantum efficiency. Complex 1 exhibits intense blue emission with high color purity (CIE x = 0.14, y = 0.12), which has been attributed to metal-to-ligand charge-transfer triplet emission based on DFT calculations.

The results of our study suggest that skin barrier function, measured by TEWL and capacitance, and clinical severity show a statistically significant correlation in patients with AD.