Biomedical subjects

E A Terwindt-Rouwenhorst

Publications and source records attributed to E A Terwindt-Rouwenhorst.

6 recordsLinked to original sources

PubMed1998

The polymer Polyactive as a bone-filling substance: an experimental study in rabbits.

The biocompatible, osteoconductive and resorbable polymer Polyactive (PA) was investigated for its performance as a bone-graft substitute. The model consisted of a 4 mm borehole, 1.5 cm distal of the major trochanter in both femurs of a rabbit, of which one was filled with a cylinder of porous PA. The other was left untreated. PA70/30 and PA60/40 were investigated, both before and after being incubated with allogenic bone marrow. Analyses were performed after 4, 8, 26 and 52 weeks and comprised dual energy X-ray absorptiometry (DXA) and image analysis of histological sections. DXA revealed an increased bone mineral density in the filled defects compared to the controls, both at the defect and immediately proximal and distal of the defect. Histology showed that gap-bridging had occurred within 8 weeks, with 80%-90% of the pores of PA70/30 and PA60/40 occupied by new bone, and an intimate bone-PA contact. PA70/30 seemed to be more suitable compared to PA60/40, in that the highest amount of bone was formed within the shortest period of time. Incubation of PA with allogenic bone marrow resulted in inflammatory reactions at the sites of implantation, which delayed bone growth, but did not prevent it. It was concluded that PA70/30 and PA60/40 are suitable bone-graft substitutes.

Journal Article↗

PubMed1993

Raphe of the posterior neural tube in the chick embryo: its closure and reopening as studied in living embryos with a high definition light microscope.

Chick embryos cultured on a curved substratum show a transient enlargement of the posterior neuropore (PN), mimicking the temporary delay of PN closure as seen in the curly tail (ct) mouse mutant (van Straaten et al. [1993] Development 117:1163-1172). In the present study the PN enlargement in the chick embryo was investigated further with a high definition light microscope (HDmic), allowing high resolution viewing of living embryos in vitro. The temporary PN enlargement appeared due to considerable reopening of the raphe of the posterior neural tube, which was followed by reclosure after several hours. The raphe was subsequently studied in detail. It appeared very irregular, with small zones of apposed, open and fused neural folds. During closure, these raphe features shifted posteriorly. A distinct fusion sequence between surface epithelium and neuroepithelium was not seen. During experimental reopening of the raphe in vitro, small bridges temporarily arose, broke and disappeared quickly; they likely represented the first adhesion sites between the neural folds. More prominent adhesion sites partly detached, resulting in bridging filopodia-like connections; they probably represented the first anteroposterior locations of neural fold fusion. Our observations in the living chick embryo in vitro thus show that the caudal neural tube has an irregular raphe with few adhesion sites, which can be readily reopened. As a result of the irregularity, the PN does not close zipper-like, but button-like by forming multiple closure sites.

Animals↗

PubMed1989

Repair of articular defects by perichondrial grafts. Experiments in the rabbit.

A defect was created in the articular cartilage of the rabbit knee leaving the subchondral bone intact. The lesion was repaired by an autologous graft of costal perichondrium and fixed with fibrin glue. The result was compared with a nontreated defect in the contralateral knee. In 26 out of 30 knees, graft fixation proved to be adequate. In the grafted group the perichondrium developed macroscopically and histologically into normal hyaline cartilage. The nongrafted defects showed only limited repair.

Animals↗

PubMed1988

Peptide immunoreactivity in developing entero-endocrine cells in endodermal grafts.

Presumptive endoderm was excised from 19-h chick or quail embryos and grafted, together with a fragment of notochord from a 48-h host chick embryo. After 14 days the graft showed differentiation towards several digestive and respiratory tract structures. Entero-endocrine cells were demonstrated in these structures. Peptide immunoreactivity in these structures was similar to some extent to the peptide spectrum in corresponding regions during normal development, though the number of demonstrable peptides per region under the conditions of grafting appeared to be higher than in control conditions.

Animals↗

PubMed1988

Drug effects on arthrosis. Comparison in rabbits of 3 modes of action.

Arthrosis was induced in adult rabbit knees by immobilization in extension. The influence of some intraarticularly injected drugs on the course of arthrosis was studied. Arteparon, Trasylol, and Kenacort A10 increased the contents of acidic glycosaminoglycans in the chondrocytes. Only Arteparon had a favorable effect on the integrity of the articular surface.

Administration, Topical↗

PubMed1988

The synthesis of peptides in enteroendocrine cells developing in explanted presumptive endoderm.

Peptide immunoreactivity was studied in grafts of endoderm from chick or quail embryos (19 hours, corresponding to stage 4- to 5 according to Hamburger and Hamilton) in the coelom of a 48 hour host embryo. The presence of gastrin, glucagon, cholecystokinin, VIP, substance P, somatostatin, bombesin, motilin, secretin, pancreatic polypeptide, neurotensin and insulin was demonstrated. The nature of the peptide(s) generally matched the regional differentiation of the enteric epithelium and the underlying mesodermal components. The findings are compatible with the concept of heterogeneity of the endoderm due to migration of epiblast derived cells.

Animals↗