Pitfalls associated with fixation of osteochondritis dissecans fragments using bioabsorbable screws.

The purpose of this study was to evaluate 2 cases in which bioabsorbable screw fixation for an osteochondritis dissecans lesion of the femoral condyle resulted in complications necessitating the need for secondary surgery. We reviewed the case history of these patients and described the circumstances under which the bioabsorbable screws were used, the events leading to the need for secondary surgery, and the ultimate outcome. In the 2 cases presented, these implants were found to retain their mechanical stiffness for many months. This resulted in articular damage in 1 case after the treated lesion failed to heal. In the second case, screw breakage 8 months after implantation resulted in it becoming a loose body, which required removal during a second arthroscopic procedure. We conclude that these implants retain their mechanical properties for many months and cannot be relied on to degrade quickly. If a treated lesion fails to heal, these implants can cause mechanical problems due to their retained structural properties.

Apoptosis during spontaneous luteolysis in the cyclic golden hamster: biochemical and morphological evidence.

The corpora lutea (CL) of the cyclic hamster are destroyed between Days 2 and 3 of the 4-day estrous cycle so that only one set is ever present (Day 1 = estrus, Day 4 = proestrus). The possibility that luteal cell death in the cyclic hamster is attributable to apoptosis was explored. The earliest histological signs of structural luteolysis were detected at 0600 h of Day 3 as evidenced by a few scattered luteal cells displaying the characteristic morphology of apoptotic cells and by a massive infiltration of neutrophils. The peaks of neutrophil influx and luteal apoptosis were reached on Day 3, 1200 h, and Day 3, 2400 h, respectively. Thus, the increase in neutrophils occurs before the major onset of luteolysis. By Day 3, 2400 h, the CL had already shrunken one third by weight, and they virtually vanished by the next Day 1. Apoptosis ultimately destroyed luteal endothelial cells, luteal cells, and neutrophils. Electrophoretic analysis of low-molecular weight DNA in luteal cell lysates revealed a definite ladder pattern of oligonucleosomal-length DNA fragments--characteristic of apoptosis--on Day 3 beginning at 1200 h. The pattern was not detectable in CL collected on Day 2. Comparing Day 3 CL collected at 0900-1200 h with those at 1500-1800 h showed that only the latter group exhibited inter-nucleosomal cleavage activity. The minimal number of CL on Day 3, 1500 h, needed to demonstrate DNA laddering was six. In summary, the electrophoretic separation of oligonucleosomal fragments and histology indicated that apoptosis occurs during spontaneous luteal regression on Day 3 of the hamster cycle. The initiation of apoptosis is not apparent until several hours after the onset of functional luteolysis. The rapidity with which apoptosis eliminates the CL over a very precise time schedule makes the cyclic hamster an ideal model to analyze the factors involved in structural luteolysis.

Clinical selection criteria for secondary examinations of the health-status of broiler flocks.

Results of post-mortem and laboratory examinations of broilers sampled randomly or selected by clinical symptoms were compared. The male:female-ratio was in all cases nearly equal for randomly sampled and selected birds. Regarding post-mortem findings, differences dependent on selection criteria were observed: in randomly-sampled birds the frequency of breast-blisters and plantar inflammations was higher than in selected broilers, whereas in the latter osteodystrophy and bursal atrophy were seen more frequently. Alterations of joints and tendon-sheaths caused by a reovirus-arthritis in one flock were seen in same frequency in randomly sampled and selected birds, respectively. Parasitological examinations revealed the highest coccidial lesion scores in selected birds with lameness or slightly retarded growth but when dwarfism birds were included into calculations, there was no significant difference among both groups. Results of bacteriological and serological examinations showed no differences between the groups.

[The effect of magnetic resonance treatment on chicken embryos]. / Untersuchungen zur Auswirkung von Magnet-Resonanz(MR)-Behandlungen auf Hühner-Embryonen.

Nuclear Magnetic Resonance (NMR) is of increasing diagnostic importance especially in human medicine. To evaluate possible side effects of this technology, embryonated chicken eggs were used as a model. Different fields (static magnetic field [1 oder 4 T], variable magnetic field [gradient] or high frequency field) were applied before the beginning and at the fifth day of incubation for different times (18.8, 37.6, 56 or 75.1 min, resp.). According to the criteria embryo-mortality, hatching-rate or vitality of the chickens, influences of the NMR-treatment were not observed.

[Salmonella gallinarum field isolates of the biovars pullorum and gallinarum]. / Uber Salmonella gallinarum-Feldisolate der Biovare Pullorum und Gallinarum.

In 40 cases salmonellae of the serovar Salmonella (S.) gallinarum were culturally isolated from domesticated gallinaceous birds submitted for diagnostic purposes in the period of 1979-1989. On the basis of the cultural and biochemical features found 35 of them could be assigned to the biovar Pullorum and 5 to the biovar Gallinarum. Of 35 isolates of the biovar Pullorum, 29 were isolated from pure bred chickens of small fancy-exhibition type flocks, 4 from floor-housed adult brown hybrid laying hens and one each from broiler chicks and pheasant chicks (Phasianus colchicus). Acute to subacute courses of the pullorum disease were observed in the 4 flocks of brown hybrid hens. Of 5 isolates of the biovar Gallinarum, 4 were isolated from adult brown hybrid laying hens kept in battery cages and one from floor-housed brown hybrid pullets of the laying type. First cases of fowl typhoid occurred early in the summer of 1988. The disease was characterized by a peracute course in the 4 flocks of brown laying hens and by a more acute course in the pullet flock. The primary source of the fowl typhoid producing organisms was not elucidated.

[Comparative studies of paramyxovirus isolates from wild birds]. / Vergleichende Untersuchungen an Paramyxovirus-Isolaten aus Wildvögeln.

As a result of a surveillance programme in North-Germany, paramyxovirus-isolates of serogroup 1 with different pathogenicity were isolated from different species of feral birds (Black-headed gull, mallard, tawny owl, tree sparrow, mute swan). In chick embryo fibroblast monolayers these isolates produced plaques exhibiting different plaque morphology. After cloning the isolates, further physicochemical, serological and pathogenicity testings were performed. On the basis of mean death time and intracerebral pathogenicity index, two of the isolates were found to be avirulent (lentogenic), whereas the others proved to be virulent (velogenic). SDS-Polyacrylamide-gel-electrophoresis showed polypeptide patterns similar to that of the PMV-1 reference strains. Summarizing all relevant findings of these investigations under consideration of the suggestions for the virological description of avian PMV (Alexander, 1987; Alexander et al., 1987; Who-Expert-Committee, 1980), including the recently established serotyping by means of monoclonal antibodies, the following designations of the PMV isolates tested herein are proposed: 1. PMV-1/black-headed gull/Germany/SSP-233/83, lentogenic NDV, monoclonal antibody group G 2. PMV-1/mallard/Germany/SSP-284/83, lentogenic NDV, monoclonal antibody group H 3. PMV-1/tawny owl/Germany/SSP-262/84, velogenic NDV, monoclonal antibody group B 4. PMV-1/tree sparrow nestling/Germany/SSP-352/84, velogenic NDV, monoclonal antibody group B 5. PMV-1/mute swan/Germany/SSP-204/85, velogenic NDV, monoclonal antibody group B.