Effect of patterned polyacrylamide hydrogel on morphology and orientation of cultured NRVMs.

We recently demonstrated that patterned Parylene C films could be effectively used as a mask for directly copolymerizing proteins on polyacrylamide hydrogel (PAm). In this work, we have proved the applicability of this technique for studying the effect such platforms render on neonatal rat ventricular myocytes (NRVMs). Firstly, we have characterised topographically and mechanically the scaffolds in liquid at the nano-scale level. We thus establish that such platforms have physical properties that closely mimics the in vivo extracellular environment of cells. We have then studied the cell morphology and physiology by comparing cultures on flat uniformly-covered and collagen-patterned scaffolds. We show that micro-patterns promote the elongation of cells along the principal axis of the ridges coated with collagen. In several cases, cells also tend to create bridges across the grooves. We have finally studied cell contraction, monitoring Ca2+ cycling at a certain stimulation. Cells seeded on patterned scaffolds present significant responses in comparison to the isotropic ones.

Electrospun aniline-tetramer-co-polycaprolactone fibres for conductive, biodegradable scaffolds.

Conjugated polymers have been proposed as promising materials for scaffolds in tissue engineering applications. The restricted processability and biodegradability of conjugated polymers limit their use for biomedical applications however. Here we synthesised a block-co-polymer of aniline tetramer and PCL (AT-PCL), and processed it into fibrous non-woven scaffolds by electrospinning. We showed that fibronectin (Fn) adhesion was dependant on the AT-PCL oxidative state, with a reduced Fn unfolding length on doped membranes. Furthermore, we demonstrated the cytocompatibility and potential of these membranes to support the growth and osteogenic differentiation of MC3T3-E1 over 21 days.

Imprint cytology of needle-localized breast lesions.

Intraoperative evaluation of nonpalpable breast lesions by frozen section frequently is not performed because of potential tissue loss, sampling errors and frozen section artifacts. In a retrospective review we found that only 50 of 503 needle-localized breast biopsies (NLBBs) were evaluated at our institution by frozen section (FS), with a sensitivity of 88%. However, intraoperative evaluation of such lesions may be essential to single-stage and cost-effective management. To this end, this study evaluated the diagnostic accuracy and potential clinical role of intraoperative imprint cytology (IIC) in NLBB. A total of 88 lesions were evaluated by IIC and permanent histology. Fifteen of them were also concomitantly evaluated by FS. All but one deferred cytologic diagnoses were correct. Twelve of 15 FS diagnoses were correct, 2 were deferred, and 1 was false negative. The data suggest that IIC may circumvent some of the difficulties associated with FS, thereby allowing immediate clinical management and later definitive histologic typing and evaluation of prognostic parameters in nonpalpable breast lesions.

Fatal pontine metastasis: clinical, CT, MRI and pathological correlates.

Progressive brainstem and cerebellar signs developed in a previously healthy 70-year-old man over a course of seven days. A pontine mass characterized by CT and MRI suggested an infiltrating primary pontine glioma. Gross postmortem examination showed a medullary-pontine hemorrhage. Microscopic analysis disclosed an undifferentiated large cell carcinoma which was found to originate from the lung. Differential diagnoses in cases of suspected brainstem lesions are given, including metastatic tumors which are rare when presenting as a solitary brainstem mass. Optimal patient management should be formulated on the basis of histopathological diagnosis rather than imprecise imaging data. Exact tissue diagnosis will also avoid an extensive and expensive search for an occult systemic cancer. The roles of radiation, chemotherapy and surgery are also discussed.