Biodegradation of polydioxanone in bone tissue: effect on the epiphyseal plate in immature rabbits.

Implants of polydioxanone (PDS), 1.3 mm in diameter, were operatively fixed in the juxta-epiphyseal area of the right proximal tibial metaphysis in six rabbits and were driven into a drill hole of equal bore through the right proximal tibial epiphyseal plate in ten rabbits. The PDS implants had biodegraded almost completely in cortical bone at 16 weeks without any significant sign of inflammation or foreign body reaction. The PDS implants did not cause any growth disturbance. Histologic studies, however, showed that seven of 10 rabbits demonstrated significant osseous bridge formation across the epiphyseal plate.     

ARTHROSCOPIC REMOVAL OF ACRYLIC CEMENT FROM UNREDUCED HIP PROSTHESIS

A case is reported in which entrapped polymethylmethacrylate following traumatic dislocation of a total hip replacement prevented complete reduction. A combined arthroscopic and fluoroscopic technique was used to remove the entrapped polymethylmethacrylate. Manipulation of the total hip prosthesis was done after removal of polymethylmethacrylate to minimize mechanical abrasion. This technique allows direct visual assessment of the articulating surfaces as well as the mechanical stability of the prosthesis. The morbidity related to the procedure is minimal and a short rehabilitation period is the major advantage.     

Involvement of microtubules in Kunjin virus replication

Summary Induction of microtubulin paracrystals (Pc) by Kunjin (KUN) virus occurred after 15 hours post-infection and were often associated with convoluted membranes (cm) and virus particles. Vinblastine sulphate which disrupts microtubulin, had an inhibitory effect on the virus production when added during the viral latent period. When infected samples were extracted with Triton X-100 and analysed by SDS-PAGE, four viral proteins were observed.     

Possible involvement of receptors in the entry of Kunjin virus into Vero cells

Summary The results obtained from electron microscopy, adsorbed and internalised virus assays and immunofluorescence studies supported that the most likely mode of entry of Kunjin virus into Vero cells was by receptor-mediated endocytosis. This was deduced indirectly from the time sequence of events that occurred. Electron microscopy revealed that endocytosis of the virus through coated vesicles had occurred. The adsorbed and internalised virus assay and immunofluorescence studies showed that there were two factors being recycled during endocytosis: the receptor for the virus and clathrin, the protein found on coated pits and vesicles. The study showed that clathrin was recycled first, followed by the receptor.     

Prevalence of sexually transmitted diseases in juvenile prostitutes and street youth

Four groups of adolescents - 35 juvenile prostitutes, 36 street youth, 31 monogamous sexually active adolescents and 35 non-sexually active adolescents - were studied between January 1, 1988 and December 31, 1988 for the presence of sexually transmitted diseases and other genital pathogens. The high prevalence of sexually transmitted diseases found in the juvenile prostitutes (Neisseria gonorrhoeae, 49%; Chlamydia trachomatis, 83%) is in contrast to other studies, which document much lower rates of infection. This could be due to the fact that there are few studies done on juvenile prostitutes as a well defined group. Despite high risk sexual behaviour, the consistent use of contraception was low. No contraceptives were used by 57% of the juvenile prostitutes and 85% of the street youth. None of the adolescents sought medical attention although 48% of the juvenile prostitutes and 53% of the street youth had genital symptoms. It appears that the present public health education and health care delivery do not reach this high risk population.     

Net postprandial utilization of [15N]-labeled milk protein nitrogen is influenced by diet composition in humans

The aim of this study was to follow the fate of dietary nitrogen to assess the postprandial utilization of purified milk protein and to determine the acute influence of energy nutrients. For this purpose, a [15N]-labeling dietary protein approach was used. Twenty-five subjects swallowed an ileal tube and ingested [15 N]-milk protein alone or supplemented with either milk fat or sucrose. The absorption and postprandial deamination of dietary protein was monitored for 8 h. Sucrose delayed the absorption of protein longer than fat, but the ileal digestibility did not differ among groups (94.5-94.8%). Sucrose, but not fat, significantly reduced the postprandial transfer of [15N]-milk nitrogen to urea. Consequently, the net postprandial protein utilization (NPPU) of milk protein calculated 8 h after meal ingestion was 80% when ingested either alone or supplemented with fat and was significantly greater with sucrose (NPPU = 85%). This study shows that energy nutrients do not affect the nitrogen absorption but modify the metabolic utilization of dietary protein in the phase of nitrogen gain. Our method provides information concerning the deamination kinetics of dietary amino acids and further allows the detection of differences of dietary protein utilization in acute conditions. The diet composition should be carefully considered, and protein quality must be determined under optimal conditions of utilization.