A 1-min double embedding method for small tissue specimens preserves comedone histology and eliminates the need for punch biopsies.

BACKGROUND: It is difficult to preserve the structure and microbial distribution inside comedonal plugs during routine processing. OBJECTIVE: The objective of this study is to determine the optimal method to preserve the comedonal corneum plug structure and inherent microorganisms thereby eliminating the need to perform punch biopsies in relevant studies. METHODS: Corneum plugs were extracted from comedones of acne vulgaris patients. Primary embedding using either a 2% agarose, 2% agar, 25% gelatin, or 2% agar + 2.5% gelatin solution was subsequently performed and the results compared. The specimens were then fixed, waxed, sectioned, and examined by light, fluorescence, and scanning electron microscopies to observe the structures and microorganisms within the plugs. RESULTS: Both the 25% gelatin and 2% agarose solutions successfully preserved the structural integrity of corneum plugs and the inherent microorganisms. When considering other factors such as thermostability, reusability, and convenience, the 25% gelatin solution was the superior choice among the four materials. CONCLUSION: We report a simple and effective method for double embedding comedonal plugs and other small tissue specimens. The technique preserves the structure and microbial distribution in situ within comedonal corneum plugs, eliminates the need for punch biopsies. This method may also be applied to other tiny and fragile tissue specimens, thereby enabling a potentially wide array of future large-scale investigations and alleviated patients' pain.

Is Human Sebum the Source of Skin Follicular Ultraviolet-Induced Red Fluorescence? A Cellular to Histological Study.

BACKGROUND: The ultraviolet-induced red fluorescence (UVRF) from human skin follicles was suggested to be a result of Propionibacterium acnes and was used for the monitoring of acne. More recent studies suggested that the UVRF may be more related to sebum rather than to microorganisms. OBJECTIVE: To clarify whether human sebum or follicular microorganisms are the source of UVRF. METHODS: We examined the fluorescence of human-derived SZ95 sebocytes, human sebaceous glands, sebum extracted from the sebaceous glands, and bacteria isolated from human hair follicles under ultraviolet light. RESULTS: SZ95 sebocytes, human sebaceous glands, and sebum do not emit UVRF. Two types of UVRF peaking at about 635 nm and at about 620 nm were detected in P. acnes and Staphylococcus epidermidis, respectively. This is the first report that S. epidermidis emits UVRF when it is anaerobically cultured and then exposed to air. CONCLUSION: Human follicular UVRF is emitted by resident bacteria, not by sebum. Therefore, UVRF may be used to monitor certain species of skin microorganisms.

Quantifying facial skin erythema more precisely by analyzing color channels of The VISIA Red images.

BACKGROUND: The VISIA Red images were developed to document and measure facial skin erythema, but diffuse erythema cannot be fully segmented by the VISIA system due to the automatic thresholding segmentation method. Moreover, topical area analysis is not available in the system. MATERIALS AND METHODS: Erythema severity degrees of 20 simulated Red images were designated 1-20 with 1-20 inflammatory lesions for each, respectively. The RGB channel mean values of each simulated image were acquired by ImageJ and relative intensity of red values calculated. RESULTS: The relative intensity of red values positively correlate to erythema severity with a coefficient of 0.999345 (p < 0.001). We also proposed a method for calibration when pustules were present in the erythema area. The method was proved by mathematical reasoning and verified by certified dermatologists. CONCLUSION: We demonstrated a simple and more precise method to quantify and compare facial skin erythema by analyzing the RGB channel values of the VISIA Red images. Our method brings convenience for erythema evaluation in dermatological studies.