Natural Pigments of Bacterial Origin and Their Possible Biomedical Applications

Microorganisms are considered one of the most promising niches for prospecting, production, and application of bioactive compounds of biotechnological interest. Among them, bacteria offer certain distinctive advantages due to their short life cycle, their low sensitivity to seasonal and climatic changes, their easy scaling as well as their ability to produce pigments of various colors and shades. Natural pigments have attracted the attention of industry due to an increasing interest in the generation of new products harmless to humans and nature. This is because pigments of artificial origin used in industry can have various deleterious effects. On this basis, bacterial pigments promise to be an attractive niche of new biotechnological applications, from functional food production to the generation of new drugs and biomedical therapies. This review endeavors to establish the beneficial properties of several relevant pigments of bacterial origin and their relation to applications in the biomedical area.

Investigation of EGFR/pi3k/Akt signaling pathway in seminomas

Activation of the receptor for epidermal growth factor (EGFR) in some testicular tumors activates several signaling pathways. Some components of these pathways are phosphorylated or mutated in testicular germ tumors (TCGT), including EGFR, Kirstein ras oncogen (KRAS) and cell surface protein of the germ cell (KIT). The latter two activate RAF ⁄MEK⁄ERK and PI3 K⁄AKT, and interconnect with the EGFR/pI3 k/Akt pathway. We investigated the expression of EGFR/pI3 k/Akt pathway proteins in seminomas and in their precursor lesion, germinal cell neoplasia in situ (GCNIS) and related genetic mutations. We used immunohistochemistry for pEGFR, pI3 k and pAkt expression with a scoring system for 46 seminoma surgical specimens: 36 classical and 10 GCNIS. In 17 samples, the mutations of EGFR (exons 19 - 21), KIT (exons 11, 17) and KRAS (exons 2, 3) were investigated using qPCR and sequencing. Of the 36 seminomas studied, 22 (61%) expressed pEGFR. Ten samples exhibited high scores for pEGFR, pI3 k and pAkt. In 5 of 17 cases (33%) some mutation was exhibited in the exons studied: 21 of EGFR (2), 17 of EGFR (1), 3 of KRAS (1) and 11 of KIT (1). Six cases exhibited nuclear translocation of EGFR; of these, four exhibited mutations of EGFR, KRAS and KIT. Eight of ten of the GCNIS expressed a high pEGFR score (80%). In 2 of 6 cases (33%), mutation was detected in exon 21 of EGFR and one smear showed EGFR translocation to the nucleus. The translocation represents a subpopulation with worse prognosis for TCGT. The EGFR/pI3 k/Akt signaling pathway is linked to TDRG1, which regulates chemosensitivity to cisplatin; this is a mechanism of resistance to treatment. TDRG1 and the EGFR/pI3 k/pAkt pathway could be therapeutic targets for seminomas resistant to cisplatin.

A six-year experience with anal cytology in women with HPV in the lower genital tract: utility, limitations, and clinical correlation

This study assessed the utility and limitations of anal cytology as a screening method for women infected with human papilloma virus (HPV) in the lower genital tract. Furthermore, this study aimed to establish risk factors for pathological anal cytology/biopsy findings, the prevalence of anatomopathological lesions associated with positive anal brushings, and the frequency of concomitant lesions of the lower genital tract. A cross-sectional, retrospective, descriptive study in 207 women with HPV-associated lesions of the lower genital tract and 25 women with immunosuppression was carried out. Anal cytology, high resolution anoscopy, and biopsy of suspicious lesions were performed. In total, 232 anal brushings were performed: 184 (79.3%) were negative, 24 (10.34%) showed atypical squamous cells of undeterminated significance, 18 (7.7%) showed low-grade squamous intraepithelial lesions, and 6 (2.6%) showed high-grade squamous intraepithelial lesion. Cytohistological correlation was obtained for 70 cases. The sensitivity of anal cytology in detecting intraepithelial lesions was 70%, whereas the specificity was 93%. The sensitivity of the method for detecting high-grade lesions (84%) was higher, than that for detecting low-grade lesions (66%). The most frequently associated pathology was vulvar lesion. It is important to perform anal brushings in women who have had lower genital tract biopsies for HPV-associated lesions due to the high prevalence of anal lesions in such patients. Anal cytology is useful for detecting high-grade lesions but the sensitivity for detecting low-grade lesions is low. It is of the utmost importance to perform high-resolution anoscopy and biopsy in women with suspicious lesions in order to confirm the pathology.