Studying Hair Growth Cycle and its Effects on Mouse Skin.

Researchers should be aware that hair growth cycle drives prominent molecular, cellular, and morphological changes to the entire skin. Thus, hair growth constitutes a major experimental variable that influences the interpretation of dermatological studies. Hair growth in mice is neither asynchronous nor fully synchronized; rather, it occurs in waves that dynamically propagate across the skin. In consequence, any given area of mouse skin can contain hair follicles in different stages of the cycle in close physical proximity. Furthermore, hair growth waves in mice are initiated by probabilistic events at different time points and across stochastic locations. The consequence of such stochasticity is that precise patterns of hair growth waves differ from mouse to mouse, even in littermates of the same sex. However, such physiological stochasticity is commonly misconstrued as a significant hair growth phenotype in mutant mice or in drug-treated mice. The purpose of this article is to provide a set of guidelines for designing reliably interpretable murine studies on hair growth and to highlight key experimental caveats to be avoided. It also informs on how to account for and minimize the impact of physiological hair cycle differences when designing and interpreting nonhair growth dermatological studies in mice.

Redo pull-through in total colonic aganglionosis due to residual aganglionosis: a single center's experience.

BACKGROUND: Reoperation for total colonic aganglionosis (TCA) may be required for residual aganglionosis after an initial radical operation. We aimed to investigate the symptoms, management, and outcomes of patients who required a redo pull-through (Redo PT). METHODS: Nine TCA patients underwent Redo PT at our center between 2007 and 2017. Their medical records were reviewed. Parental telephone interviews that included disease-specific clinical outcomes were conducted, and post-operative complications and long-term outcomes (including height-for-age/weight-for-age and bowel-function score) were compared to those of single-pull-through (Single PT) patients (n = 21). RESULTS: All the nine Redo PT patients suffered obstruction within 1 month after the initial operation that could not be alleviated by conservative treatment. All abdominal X-ray/contrast barium enemas showed proximal bowel dilatation, indicating residual aganglionosis. The median ages at the initial operation and Redo PT were 200 and 509 days, respectively. Reoperation consisted of an intraoperative frozen biopsy and a modified laparotomic Soave procedure in all patients. Post-operative complications included perianal excoriation (n = 3), intestinal obstruction (n = 2), enterocolitis (n = 2), and rectovestibular fistula (n = 1). Seven Redo PT patients were followed up for a mean time of 7.1 ± 2.3 years; six (85.7%) had good growth and four (57.1%) had good bowel-function recovery. Post-operative complications and long-term outcomes were almost equal between the Redo PT and Single PT groups (all P > 0.05). CONCLUSION: TCA patients with recurrent obstructive symptoms and dilated proximal bowel may have residual aganglionosis after an initial operation. Redo PT is effective and provides good long-term outcomes comparable to those of patients who benefited from Single PT.

Combined effects of independent variables on yield and protein content of pectin extracted from sugar beet pulp by citric acid.

The extraction of pectin from sugar beet pulp by citric acid was carried out under different conditions using Box-Behnken design for four independent variables (pH, temperature, time and liquid to solid ratio). The yield of sugar beet pulp pectin ranged from 6.3% to 23.0%, and the content of protein from 1.5% to 4.5%. All independent variables significantly affected the yield, and all variables except liquid to solid ratio significantly affected the protein content. The yield increased as decreasing pH of extracting solution, extending time and advancing temperature, and an opposite relationship of effects between variables and content of protein was obtained. The chemical composition of collected samples was determined. Moreover, from the results of emulsifying properties study, the extracted pectin from sugar beet pulp could prepare steady oil-in-water emulsions. Therefore, it was inferred that the extraction conditions could influence yield and protein content, resulting in different emulsifying property.