Alpaca fiber growth is mediated by microRNA let-7b via down-regulation of target gene FGF5.

MicroRNAs are very small endogenous RNA molecules that play a crucial role in an array of biological processes, including regulation of skin morphogenesis. The microRNA let-7b is thought to modulate animal hair growth, by binding target genes that encode growth factors. Fibroblast growth factor 5 (FGF5) has been previously reported to be involved in the initiation of the catagen phase of hair growth. In this study, we combined previous reports with bioinformatic analysis techniques to identify and validate FGF5 and, using lucerifase assay, confirmed targeted binding of let-7b to FGF5. To investigate the interaction between let-7b and FGF5, alpaca skin fibroblasts were transfected with let-7b over-expression vectors, and then mRNA and protein expression levels of FGF5 and the gene encoding its receptor, FGFR1, were evaluated. Levels of FGF5 mRNA and protein were remarkably lower in transfected groups, as compared to controls. In summary, this study confirmed that let-7b acts as a regulator of skin morphogenesis, by directly targeting FGF5 and down-regulating its expression. It provides the evidence of hair growth regulated by miRNAs in animals and may have important applications in wool production.

Association of peroxisome proliferator-activated receptor-delta polymorphisms with sugar metabolism indices and tumor necrosis factor alpha level.

This study aims to investigate the association of peroxisome proliferator-activated receptor (PPAR) delta -87T/C polymorphism with several sugar metabolism indices and tumor necrosis factor α (TNF α) level. The body mass index (BMI), waist size, and levels of fasting plasma glucose, serum lipid, fasting insulin, TNFα, and PPAR delta -87T/C of 286 patients with type 2 diabetes mellitus (T2DM) and 158 subjects with normal fasting glucose (NFG) were measured in a Dalian population. The distribution of genotypic frequencies between T2DM and NFG were not significantly different (χ(2) = 0.012, P = 0.994). BMI, fasting blood glucose (FBG), homeostasis model assessment-estimated insulin resistance (HOMA-IR), triglyceride, and TNFα levels were significantly different among different T2DM genotypes. HOMA-IR and FBG were significantly different among different NFG genotypes. The PPAR delta -87T/C polymorphism is known to be closely related with glucose levels and lipid metabolism. A close relationship was also found between HOMA-IR and TNFα levels and HOMA-IR and FBG in T2DM and NFG, respectively.

Meta-analysis of the relationship between p21 Ser31Arg polymorphism and lung cancer susceptibility.

The cyclin-dependent kinase inhibitor 1A (also known as p21) is thought to be involved in tumor development by mediating cell cycle arrest through the inhibition of cyclin/CDK activity. To explore the relationship of Ser31Arg polymorphism in the p21 gene with the risk of developing lung cancer, we performed an overall and stratified meta-analysis based on ethnicity, lung cancer subtypes and source of controls, with six eligible studies (2366 cases and 3320 controls). No significant variation in lung cancer risk was detected in any of the genetic models in the overall, and the ethnicity-based and cancer subtype-based subgroup analyses. However, in the subgroup analysis based on source of controls, significant opposite associations were observed; a significantly increased lung cancer risk was observed in the hospital-based control subgroup, while a significantly decreased lung cancer risk was detected in the mixed-source control and unknown-source control subgroups. In summary, based on our meta-analysis, p21 Ser31Arg polymorphism does not appear to act as an independent lung cancer risk factor and is more likely to act together with other genetic and non-genetic factors in the development of lung cancer; this needs further investigation.

Unrecognized spotted fever group rickettsiosis masquerading as dengue fever in Mexico.

Although Rocky Mountain spotted fever was documented in northern Mexico during the 1940s, spotted fever group (SFG) rickettsioses have subsequently received little attention in Mexico. In this study, sera collected in 1993 from 50 patients from the Mexican states of Yucatan and Jalisco, who were suspected clinically to have dengue fever but had no antibodies to dengue virus, were examined by indirect immunofluorescence for IgM antibodies reactive with Rickettsia rickettsii, R. akari, and R. typhi. Twenty (40%) of the patients' sera contained IgM antibodies to SFG rickettsiae at a titer of 128 or greater. Among five sera reactive only against R. akari, four were from patients in Jalisco where a cluster of cases occurred in June and July. Among five sera reactive only with R. rickettsii, all were from Yucatan patients. Sera of 10 patients contained antibodies reactive with antigens shared by R. rickettsii and R. akari. The clinical signs and symptoms (fever, 100%; myalgia, 95%; headache, 85%; rash, 85%) were similar to those of dengue fever patients identified in this study. However, the incidence of rash was substantially higher than the nondengue, nonrickettsiosis patients. One or more SFG rickettsioses appear to be present in areas of Mexico not previously recognized to harbor these organisms. The etiologic agent or agents are as yet unknown.