Comparative analysis of different collagen-based biomaterials as scaffolds for long-term culture of human fibroblasts.

Biodegradable scaffolds, along with cells, are important components of most tissue-engineered constructs. In the study, there is a comparison of the behaviour of human fibroblasts cultured for up to six weeks in four different collagen-based three-dimensional matrices, in the form of sponges composed of pure native type I collagen (control), of collagen-GAG-chitosan (CGC) and of collagen cross-linked by two concentrations of diphenylphosphorylazide (DPPA-2 and DPPA-3). Variations in size and weight of the sponges, as well as fibroblast growth and migration, and total protein and collagen synthesis, are determined with time in culture. Owing to their low thermal stability, the partial denaturation and dissolution of the control sponges after incubation at 37 degrees C lead to considerable contraction and low cell proliferation. CGC sponges, stabilised by ionic interactions between the different components, show, after six weeks, limited contraction (20%) and weight increase (10% when seeded) and high cell growth (threefold increase). Similar results are obtained with weakly, cross-linked (DPPA-2) collagen sponges. Highly cross-linked (DPPA-3) sponges do not contract, whereas weight gain and cell proliferation are no different from those found with CGC and DPPA-2 sponges. Similar levels of total protein and collagen synthesis are shown for fibroblasts seeded in different matrices, with a slight general decrease (twofold) after three weeks, a much lower value than that observed with fibroblasts in culture within a contracted collagen gel (sixfold). Furthermore, the fraction of neo-synthesised collagen deposited in the sponges after six weeks represents more than 60% of the total, compared with only 10% obtained with fibroblasts in monolayer culture or 30% within a collagen gel. These results indicate that the matrices, particularly the CGC and DPPA-2 sponges, provide excellent supports for fibroblast growth and the formation of dermal and skin equivalents.

Primary myenteric plexus alterations as a cause of megacolon in Von Recklinghausen's disease.

This is a case report of a megacolon in a 26 years old male patient having typical von Recklinghausen's disease. Exploratory laparotomy shows no neurofibroma on digestive tract. Myenteric plexus study of colic resection specimen following B. Smith technique reveals marked alterations. These alterations are both quantitative (hyperhypoganglionosis) and qualitative (ganglion cells are irregular in shape and size, dendritic processes are hypertrophic, irregular; schwannosis; no inflammatory infiltration). The patient suffers no more transit disorders after adequate resection of this megacolon.

[Traumatic intestinal infarction (author's transl)]. / L'infarctus intestinal traumatique.

A study of 25 cases of traumatic intestinal infarction, often old cases, did not show any characteristic clinical picture or course but showed the following points: --abdominal contusion, even mild, may induce intestinal infarction, without any other intra- or retroperitoneal lesion. The frequency of infarction is low, but the notion of trauma is often neglected; --the ileum and ascending colon are most commonly involved, and infarction usually follows a thrombosis of the mesenteric veins. When there is an arterial infarction, this is usually due to mobilisation of an atheromatous plaque; --the clinical course usually includes an interval between the trauma and the infarction, due to a prodromic phase corresponding to the constitution then the extension of the thrombosis. These characteristics suggest a relationship between infarction and venous infarction in general, especially postoperative infarction, where there is local trauma and slowing of the circulation and hypercoagulability and raised platelet count. The treatment is nevertheless the same, associating intestinal resection and exploration with endarterectomy of the vascular pedicles and prolonged postoperative anticoagulant treatment.