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The aim of this investigation was to analyze the midterm results obtained with the metaphyseal fixation principle of the thrust plate prosthesis (TPP). Survival of 214 implants in 204 patients was analyzed. Clinical (Harris hip score) and radiologic examinations were carried out on 157 of 190 TPP with a postimplantation follow-up period of at least 5 years. Failure rate was 7.0% (9 aseptic and 6 septic loosening). Harris hip score increased from 36.9 +/- 13.5 points preoperatively to 91.2 +/- 13.1 points at follow-up. Eleven TPPs showed radiolucent lines not indicating prosthetic loosening. Thrust plate prosthesis is not an alternative to stemmed endoprostheses. It may be rarely indicated in very young patients where, because of their age, several revision operations can be expected.

Among the biological problems that arise in long duration spaceflights, the effects of weightlessness and ionizing radiation appear to be the two main risk factors. Eggs of the stick insect Carausius morosus were exposed to spaceflight conditions during the 12.56 day Biosatellite mission Cosmos 1887. Five different ages were used, representing different sensitivities to radiation and different capacities for regeneration. During spaceflight the eggs continued their development. Already, in the Spacelab D1 mission in 1985, it has been shown that microgravity leads to a reduced hatching rate of eggs exposed during the early steps of development. When the eggs were hit by a heavy ion, a further but not significant reduction of the hatching rate was observed. Hatching was normal for eggs which were exposed on a 1 g reference centrifuge in space. Heavy ion hits caused body anomalies. The combined action of heavy ions and microgravity resulted in an unexpectedly high rate of anomalies. In the experiment on Cosmos 1887 these results were confirmed. Studies on the embryonic development before hatching showed no major difference between flight and ground control specimen, neither in speed of development nor in morphological anomalies. Hatching therefore seems to be the critical point in insect ontogenesis.

Two layers of AgCl detectors with a total surface of 90 cm2 were flown. Tracks of nuclei, from light (Z>4) up to the heaviest were recorded and could be distinguished by their geometrical trackwidths. The tracks were divided into five groups of atomic numbers, and their abundance was measured. Also the number of surviving nuclear stars was counted. 22.5 cm2 of the detector surface were covered with eggs of Artemia salina. The detectors could be developed without removing the eggs, so that the spots hit could be determined directly. The radiation effect on these eggs is being investigated.

The Biostack experiment (Principal Investigators: H. Bucker) aboard Apollo 16 contained one unit with eggs of the brine shrimp Artemia salina. The eggs were fixed in polyvinyl alcohol foils. Nuclear emulsions and plastics were used as track detectors. The development of 260 eggs hit by cosmic heavy ions was investigated. It differed significantly from the development of the flight controls--eggs flown in the Biostack but not hit by heavy ions--and of the ground controls. From these results it was concluded that a hit of a single heavy ion may injure the encysted blastula. This damage was found to influence the gastrula formation and even the hatching process of the nauplius. Abnormalities of the orthonauplius were observed during the development of the hit eggs. These are shortened extremities, or abnormal thorax or abdomen. In addition, in the Biostack II aboard Apollo 17 eggs of Tribolium confusum and Carausius morosus were included. The influence of single heavy ions on the development process of these highly organized insects was investigated.

The influence of cosmic radiation and/or microgravity on insect development was studied during the 7 day German Spacelab Mission D1. Eggs of Carausius morosus of five stages differing in sensitivity to radiation and in capacity to regeneration were allowed to continue their development in the BIORACK 22 degrees C incubator, either at microgravity conditions or on the 1 g reference centrifuge. Using the Biostack concept--eggs in monolayers were sandwiched between visual track detectors--and the 1 g reference centrifuge, we were able to separate radiation effects from microgravity effects and also from combined effects of these two factors in space. After retrieval, hatching rates, growth kinetics and anomaly frequencies were determined in the different test samples. The early stages of development turned out to be highly sensitive to single hits of cosmic ray particles as well as to the temporary exposure to microgravity during their development. In some cases, the combined action of radiation and microgravity even amplified the effects exerted by the single parameters of space. Hits by single HZE particles caused early effects, such as body anomalies, as well as late effects, such as retarded growth after hatching. Microgravity exposure lead to a reduced hatching rate. A synergistic action of HZE particle hits and microgravity was established in the unexpectedly high frequency of anomal larvae. However, it cannot be excluded, that cosmic background radiation or low LET HZE particles are also causally involved in damage observed in the microgravity samples.

After penetrating the Biostack capsule, some of the HZE particles hit the biological objects carried: bacterial spores (Bacillus subtilis), seeds (Arabidopsis thaliana and Vicia faba), and shrimp eggs (Artemia salina). The different biological objects were affected by heavy ions in widely varying ways. A broad range of radiobiological investigations has been carried out in regard to the objects' response to HZE particles. The most sensitive biological objects in the Biostack experiments proved to be the shrimp eggs. The development of 500 eggs hit by heavy cosmic ions was investigated. This differed significantly from the flight controls (eggs flown in the Biostack but not hit by heavy ions) and from the ground controls. From this it has been concluded that penetration on the part of a single heavy ion may injure the encysted blastula. This damage was found to influence gastrula formation and even the hatching process of the nauplius. Abnormalities (increased by a factor of 10) in the orthonauplius were observed during the development of the hit eggs; they consisted, for example, of shortened extremities or an abnormal thorax or abdomen. In addition, eggs of Tribolium confusum and Carausius morosus, which were included in Biostack 2 (Apollo 17), have been investigated, and the influence of single heavy ions on the development process of these highly organized insects has been studied.

Eggs of Carausius morosus were exposed to spaceflight conditions in two spaceflight missions, the German 7 day Spacelab Mission D1 and the Soviet 12.56 day Biosatellite Mission "COSMOS 1887". During spaceflight the eggs continued their development. Eggs of five different ages representing different sensitivity to radiation and different capacity to regeneration were used to investigate the influence of cosmic radiation and/or microgravity on insect development. Using the Biostack concept--eggs in monolayers sandwiched between nuclear track detectors--and the 1 g reference centrifuge of BIORACK in D1 we were able to separate effects of heavy ions of the cosmic radiation from microgravity effects and also from combined effects of these two factors in space. After retrieval, hatching rates, embryonic and larval growth kinetics and anomaly frequencies were determined. Microgravity leads to a reduced hatching rate of eggs exposed in the early stages of development. Hatching was normal in eggs which were exposed on the 1 g reference centrifuge. Hits by heavy ions caused body anomalies. The combined action of heavy ions and microgravity resulted in an unexpectedly high frequency of anomalies. These results obtained from the Spacelab Mission D1, were confirmed in an experiment onboard of COSMOS 1887. In addition to the previous analysis, embryonic development before hatching was followed which showed no major difference between flight and the ground control specimens. Since a reconfirmation of reduced hatching rates was observed in COSMOS 1887, too, the above results suggest some microgravity induced functional impairment of the hatching activity, rather than blockage in embryonic development.

The radiobiological properties of the heavy ions of cosmic radiation were investigated on Spacelab 1 by use of biostacks, monolayers of biological test organisms sandwiched between thin foils of different types of nuclear track detectors. Biostacks were exposed to cosmic radiation at several locations with different shielding environments in the module and on the pallet. Evaluations of the physical and biological components of the experiment to date indicate that in general they survived the spaceflight in good condition. Dosimetric data are presented for the different shielding environments.

The object of the Biostack experiment is to study the biological effects of high ZE particles of cosmic radiation in order to obtain information on the mechanism of these particles in biological matter. For this purpose individual local evaluation methods have been developed which allow one to identify each biologically effective particle and to correlate the individual hitting particle with the biological effect produced. The Biostack experimental package contains a series of monolayers of selected biological objects (Bacillus subtilis spores, Arabidopsis thaliana seeds, Vicia faba radiculae, Artemia salina eggs) with each layer sandwiched between several different cosmic ion track detectors (nuclear emulsions, cellulose nitrate, polycarbonate). By this arrangement a variety of biological effects due to a single penetrating particle can be analysed. Influence on cellular and tissue development, nuclear damages, and mutation induction are the main investigated effects. These space flight findings will be completed by results of balloon flight and accelerator experiments.

Much data concerning radiation in space as a serious danger to astronauts can be obtained in laboratories on Earth. For different parameters we investigated the relative biological efficiency (RBE) of 14-MeV neutrons on mice, rats and guinea pigs (being wholly exposed). Also the mitosis inhibition for isolated cells was determined. The RBE values found were: for lethality in the LD50(30d)-region--about 2 (for mice, rats and guinea pigs); for reduction due to radiation of living weight of different animals--2 to 3; for reduction of small gut weight of rats and guinea pigs--2.5 and 2; for histological changes in blood and albumin serum (rats and guinea pigs)--about 2; for the highly sensible cells of the lense epithelium from eyes of rabbits--2.5; for the mitosis inhibition of HeLa cells--2.5. The apparatus for radiation tests is described and measuring methods are indicated. The radiation of the whole body of mice, rats and guinea pigs was determined by activating of MgCl2 solution filled into phantoms. By means of a computer, the depth-dose curve can be determined for larger biological objects.