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Background and aims Vitiligo is an acquired pigmentary disorder of skin and hair. Active melanocytes in hair follicles can be detected by DOPA and immunohistochemical staining, while amelanotic melanocytes can only be detected by the latter. None of the studies on hair melanocytes in vitiligo discussed the effect of disease duration on these melanocytes. Here, we study the presence of melanotic and amelanotic melanocytes in vitiligo hair follicles and statistically correlating their presence with the disease duration. Methods This study was conducted on 30 patients with vitiligo and 10 normal volunteers. Three biopsies were taken from each patient: two from black and white hairs from vitiliginous areas and the third from apparently normal skin of the same patients. Sections were stained by DOPA reaction and NKI/beteb then examined for the presence of melanocytes. The presence of melanocytes and the disease duration were correlated statistically using the t-test. Results Active melanocytes were detected in black hairs of 6.7% of vitiligo patients and in 100% of apparently normal skin of the same patients and controls. On examining black hairs of the 28 vitiligo patients with negative DOPA reaction, 19 of them (67.9%) showed positive NKI/beteb stain. Disease duration was inversely correlated with the melanocytes’ presence within hair follicles. Melanocytes were absent from 100% of white hairs. Conclusions The melanotic melanocytes were the first target of the disease process followed by the amelanotic melanocytes. Since the disappearance of the latter was inversely correlated with the disease duration, early treatment in vitiligo is advised. Conflicts of interest None declared. [ABSTRACT FROM AUTHOR]

The article focuses on perifollicular inflammatory infiltrate in the acquired depigmentary disorder vitiligo. It reports that vitiligo involves loss of melanocytes from the epidermis and hair follicles. Diagnosis for the disorder which includes skin inspection and the use of Wood's light are also mentioned. The skin disorder's lesions which usually presents with a thin lymphocytic infiltrate and rarely a heavy lymphocytic infiltrate are discussed.

The article presents a retrospective study regarding the presence of eosinophils in the inflammatory infiltrate of nonsegmental vitiligo. According to the article, eosinophils are usually considered as the end-stage effector cells of innate immunity. From the biopsies of 30 patients with nonsegmental vitiligo, 20 of them had stable vitiligo and the remaining 10 had active vitiligo. It notes that the stability of vitiligo has been defined as a period varying from six months to two years.

An optimum coding of the parameters of a formant speech synthesizer has been found. The optimization procedure is based on statistical and subjective criteria. The synthesizer is a parallel formant synthesizer. The utterances chosen for experimentation are groups of French high-quality synthetic vowel-consonant sounds (voiced stops and voiced fricatives). The proposed procedure consists of three principal steps. The first step is a statistical study on the parameters in order to find the effective range of variation of each parameter. The second step is to determine by subjective evaluatioa the minimum number of bits and type of quantization (linear or logarthmic) needed to quantize each parameter. The third and final step is to optimize the sampling interval depending on the nature of speech events. In fact a variable sampling interval is proposed. We have applied the proposed procedure in order to minimize the total bit-rate necessary for encoding the parameters of the synthesizer and in the same time obtaining synthetic utterances indistinguishable from original utterances obtained from nonoptimized parameters. Finally, throughout this study we have emphasized the different characteristics of each type of the utterances. [ABSTRACT FROM AUTHOR]