Identification of the critical level of implantation of an osseointegrated prosthesis for above-knee amputees

The aim of our study was to identify potential critical levels of implantation of an osseointegrated prosthesis for above-knee amputees. The implant used was the OPRA system. It was inserted in the femur at four different amputation heights, characterized by their residual limb ratios (0.299, 0.44, 0.58 and 0.73). The stress and strain distribution was evaluated in the bone-implant system during walking, considering a body mass of 100 kg. Considerably high stimulus (11,489 με) in the tissue near the tip was found at the highest implantation level. All models presented small non-physiologic stress values in the tissue around the implant. The results revealed that the implantation level has a decisive effect on bone-implant performance. Mainly, the analysis indicates adverse biomechanical conditions for implantations in very short residual limbs.     

Pelodera (syn. Rhabditis) strongyloides as a cause of dermatitis – a report of 11 dogs from Finland

Background  

Pelodera (Rhabditis) strongyloides is a small saprophytic nematode that lives in decaying organic matter. On rare occasions, it can invade the mammalian skin, causing a pruritic, erythematous, alopecic and crusting dermatitis on skin sites that come into contact with the ground. Diagnosis of the disease is based on case history (a dog living outdoors on damp straw bedding) with characteristic skin lesions and on the demonstration of typical larvae in skin scrapings or biopsy. Pelodera (rhabditic) dermatitis cases have been reported mainly from Central European countries and the United States.     

Control of transgenesis in higher cells: the procell transposon Tn10 TetR mRNA has several major hairpins and can be unstable in eucells.

The TetR regulatory gene from the transposon Tn10 has some excellent characteristics for transgenic control in higher cells. However, we experienced severe problems with mRNA instability for this gene in eucells (CHO cells). This may be connected with the existence within the Tn10 TetR mRNA of several sizeable hairpins. They resemble canonical RNase E sites for mRNA destabilisation in procells and possibly also in eucells. Two of the hairpins also included sequences resembling eucell hnRNA polyadenylation or processing signals. The TetR counterpart from the plasmid RA1 appears to have less of the hairpin secondary structure; perhaps because of this, it did not present these mRNA instability problems in CHO cells, and it may prove a valuable alternative for transgene control in gene therapy and biotechnology.     

Rodent common fragile sites: Are they conserved? Evidence from mouse and rat

Nineteen fragile sites induced by aphidicolin in lymphocyte cultures from the laboratory mouse are documented. These sites are compared with previously described fragile sites induced in mouse fibroblast systems, and then with those reported on chromosomes which have been evolutionarily conserved between the mouse and the laboratory rat. Of a total of 38 fragile sites thus far identified in mouse fibroblasts and lymphocytes, only 4 sites are common to the two cell types; 34 sites show no correspondence of loci. The reason for this discrepancy is unclear, but it is possible that these data may indicate some degree of tissue specificity of fragile site expression in the mouse. Eight autosomes in the mouse and rat retain straightforward and nearly complete banding homology. To test the hypothesis that fragile sites are conserved between the two species, we compared these eight autosomes with regard to number and distribution of fragile site loci. A total of 30 fragile sites is distributed over the conserved chromosomes. Only 4 (possibly 5) are common to both species; 18 are found in the rat but not the mouse, and 4 are found in the mouse but not the rat. Of the 4 shared sites, notable differences in frequency of expression exist. Our comparisons show that: (1) a small numer of fragile sites is conserved; (2) a large number of fragile sites is not conserved, and (3) some sites which are conserved are quite different in the frequency at which they are expressed in the two species, indicating that the sites themselves may have undergone evolutionary change. The chromosomes compared between mouse and rat are widely conserved among murid rodents and thereby offer further opportunities to investigate fragile site phenomena in diverse species.     

Production of epoxygenase metabolite by human reproductive tissues

Human amnion, trophoblast and umbilical vein endothelial cells synthesise an arachidonic acid metabolite which is neither a lipoxygenase nor a cyclo-oxygenase product. It is sensitive to stimulants and inhibitors of the cytochrome-P450-dependent epoxygenase system and co-migrates on HPLC with 14,15-epoxyeicosatrienoic acid (14,15-EET), which is an epoxygenase product. The function of 14,15-EET in these reproductive tissues is unknown, but it may be involved in the maintenance of vascular function.