Cell interaction with three-dimensional sharp-tip nanotopography

Cells in their native microenvironment interact with three-dimensional (3D) nanofeatures. Despite many reports on the effects of substrate nanotopography on cells, the independent effect of 3D parameters has not been investigated. Recent advances in nanofabrication for precise control of nanostructure pattern, periodicity, shape, and height enabled this systematic study of cell interactions with 3D nanotopographies. Two distinct nanopatterns (posts and grates) with varying three-dimensionalities (50-600 nm in nanostructure height) were created, while maintaining the pattern periodicity (230 nm in pitch) and tip shape (needle- or blade-like sharp tips). Human foreskin fibroblasts exhibited significantly smaller cell size and lower proliferation on needle-like nanoposts, and enhanced elongation with alignment on blade-like nanogrates. These phenomena became more pronounced as the nano topographical three-dimensionality (structural height) increased. The nanopost and nanograte architectures provided the distinct contact guidance for both filopodia extension and the formation of adhesion molecules complex, which was believed to lead to the unique cell behaviors observed. (c) 2006 Elsevier Ltd. All rights reserved

The influence of glycosaminoglycans and cross-linking agents on the phenotype of hepatocytes cultured on collagen gels

The use of primary hepatocyte cultures as in vitro models for studying xenobiotic metabolism and toxicity is limited by the loss of liver-specific differentiated functions with time in culture and the inability of the cells to proliferate. The aim of this study was to investigate the effect of incorporating 20% chondroitin-6-sulphate (Ch6SO4), a glycosaminoglycan (GAG), into collagen gels (0.3% w/v) and crosslinking the gels with either 1-ethyl-3-(3-di methylaminopropyl) carbodiimide (EDAC) or 1,6-diaminohexane (DAH) on the expression of glutathione-Stransferases (GSTs) and the activity of cytochrome P450 in hepatocytes cultured for 48 hours and 7 days. Hepatocytes were isolated from male Sprague-Dawley rats by collagenase perfusion. Cell homogenates were immunoblotted against class {alpha} and {pi} GST subunits. To measure cytochrome P450 activity, testosterone hydroxylation was assessed. Viability of the cultured cells was assessed by confocal laser scanning microscopy using the vital stain carboxyfluorescein diacetate (CFDA). Cells cultured on gels crosslinked with EDAC were dead by 48 hours as judged by lack of CFDA-derived fluorescence and absence of GST bands on the immunoblots. The viability and morphology of the cells were unaffected by any of the other components of the substrata tested. Expression of GSTs indicated that the hepatocyte phenotype was stable for at least 48 hours. The addition of GAG did not improve the phenotype at either 48 hours or 7 days in culture, but the combination of GAG and DAH crosslinking improved GST expression in the 7-day cultures. However, the hepatocyte cytochrome P450 activity did not show any improvement on any of the gels. The combination of GAG and DAH crosslinking provided the most stable substratum environment in terms of GST expression in hepatocytes

H-Type Congenital Tracheoesophageal Fistula: University of Iowa Experience 1985 to 2005

Objectives: We review the diagnostic workup, associated disorders, surgical technique, and postoperative course of patients who underwent repair of H-type tracheoesophageal fistulas. Methods: We performed a retrospective chart review of patients who received a diagnosis of tracheoesophageal fistula at the University of Iowa. Results: Seven patients with an H-type tracheoesophageal fistula and a single patient with a missed proximal fistula associated with esophageal atresia were identified. Their symptoms included coughing with feeding, recurrent pneumonia, and episodic cyanosis. A delay in diagnosis was seen in 4 patients and ranged from 2.5 months to 5.9 years. In all patients, the diagnosis was made with an esophagogram. The level of the fistulas was between C5 and T3. and all were successfully repaired via a right cervical approach. Conclusions: A high index of suspicion for an H-type tracheoesophageal fistula should be maintained in the presence of neonatal respiratory symptoms, as the condition can be associated with a delay in diagnosis. Repeat esophagograms and bronchoscopy may be required for diagnosis. In the postoperative period, airway obstruction is a potential risk; however, long-term difficulty with swallowing, respiration, and phonation was not observed. © 2007 Annals Publishing Company. All rights reserved

Effects of resistance exercise, collagen ingestion and circulating oestrogen concentration on collagen synthesis in a female athlete: A case report

We investigated the effects of resistance exercise (RE), hydrolysed collagen (HC) ingestion and circulating oestrogen concentration on collagen synthesis in a naturally menstruating female CrossFit athlete. In a double-blind, randomised cross-over design, the participant (36 years; height 1.61 m; mass 82.6 kg) consumed 0 g or 30 g HC prior to performing back-squat RE when endogenous circulating oestrogen concentration was low (onset of menses, OM) and high (late follicular phase, LF) during two consecutive menstrual cycles. Ten 5-mL blood samples were collected during each of the four interventions to analyse concentrations of serum 17β-oestradiol, and biomarkers of type I collagen turnover, i.e. serum procollagen type Ⅰ N-terminal propeptide, (PINP, a biomarker of collagen synthesis) and plasma β-isomerized C-terminal telopeptide of type I collagen (β-CTX, a biomarker of collagen breakdown), as well as the serum concentration of 18 collagen amino acids. 17β-oestradiol concentration was 5-fold higher at LF (891 ± 116 pmol∙L-1) than OM (180 ± 13 pmol∙L-1). The PINP concentration × time area under the curve (AUC) was higher in the 30 g HC OM intervention (201 μg∙L-1∙h) than the 30 g HC LF (144 μg∙L-1∙h), 0 g HC OM (151 μg∙L-1∙h), and 0 g HC LF (122 μg∙L-1∙h) interventions. β-CTX concentration decreased 1.4-fold from pre-RE to 6h post-RE in all interventions. Thus, high circulating oestrogen concentration was associated with lower collagen synthesis following RE in this female athlete. Ingesting 30g HC, however, augmented the collagen synthesis response at LF and particularly at OM

Secondary closure of a giant omphalocele by translation of the muscular layers: a new method.

Contains fulltext : 48359.pdf (publisher's version ) (Closed access)The current report describes a case of an infant girl with a giant omphalocele in whom a new surgical technique was used for closing the abdominal wall after epithelialization of the omphalocele for 16 months. The technique used was translation of the muscular layers of the abdominal wall. The functional and cosmetic results appear superior compared with other suggested treatments used for this abdominal wall defect