Active and Passive Immunization Against Staphylococcus aureus Periprosthetic Osteomyelitis in Rats.

BACKGROUND/AIM: Staphylococcus aureus infection associated with orthopedic implants cannot always be controlled. We used a knee prosthesis model with implant-related osteomyelitis in rats to explore induction of an effective immune response with active and passive immunization. MATERIALS AND METHODS: Fifty-two Sprague-Dawley rats were divided into active (N=28) and passive immunization groups (N=24). A bacterial inoculum of 103 S. aureus MN8 was injected into the tibia and the femur marrow before insertion of a non-constrained knee prosthesis in each rat. The active-immunization group received a synthetic oligosaccharide of polysaccharide poly-N-acetylglucosamine (PNAG), 9G1cNH2 and the passive-immunization group received immunization with immunoglobulin from rabbits infected with S. aureus. RESULTS/CONCLUSION: Active immunization against PNAG significantly reduced the consequences of osteomyelitis infection from PNAG-producing intercellular adhesion (ica+) but not ica- S. aureus. Passive immunization resulted in better clinical assessments in animals challenged with either ica+ or ica- S. aureus, suggesting a lack of specificity in this antiserum.

[Dissection is still important when learning anatomy]. / Dissektionsundervisning er fortsat vigtig ved indlæring af anatomi.

Dissection and prosection require a donation programme of cadavers for education and research. The importance of maintaining the donation programme and the significance of dissection as a teaching method when learning anatomic structures and obtaining surgical skills are evaluated.

A novel knee prosthesis model of implant-related osteomyelitis in rats.

BACKGROUND AND PURPOSE: There have been numerous reports of animal models of osteomyelitis. Very few of these have been prosthesis models that imitate human conditions. We have developed a new rat model of implant-related osteomyelitis that mimics human osteomyelitis, to investigate the pathology of infection after orthopedic implant surgery. METHODS: 2 wild-type strains of Staphylococcus aureus, MN8 and UAMS-1, and their corresponding mutants that are unable to produce poly-N-acetyl glucosamine (PNAG) (ica::tet) were injected into the medullary canals of the femur and tibia at 3 different doses: 10(2), 10(3), and > 10(4) CFU/rat. We measured clinical signs, inflammatory markers, radiographic signs, histopathology, and bacteriology in the infected animals. RESULTS: An inoculum of at least 10(4) cfu of either wild-type bacterial strain resulted in histological, bacteriological, and radiographic signs of osteomyelitis with loosening of the prosthesis. An inoculum of 10(3) CFU gave signs of osteomyelitis but the prosthesis remained in situ. Bacterial inocula of 10(2) cfu gave no signs of osteolysis. INTERPRETATION: We have established a new knee prosthesis model that is suitable for reliable induction of experimental implant-associated osteomyelitis with the prosthesis in situ, using a small inoculum of S. aureus. At a dose of 10(3) CFU/rat, bacteria unable to produce PNAG (ica::tet) had only minor defects in their virulence.

[Malignant tumours of the hand]. / Håndens maligne tumorer.

Malignant tumours of the hand are rare and are often misdiagnosed. A painful swelling of the hand or digits are often diagnosed with an infection, benign tumours such as ganglion cysts, or arthritis. Wounds that do not heal despite adequate treatment should be biopsied to rule out malignancy. A correct diagnosis without delay is important because the life expectancy, due to a metastasis on the hand or fingers is approximately six months.

[Acute infections of the hand]. / Håndens akutte infektioner.

Hand infections can result in significant morbidity if not appropriately diagnosed and treated. Host factors, location and circumstances of the infection are important guides to initial treatment strategies. Many hand infections improve with early splinting, elevation and appropriate antibiotics based on bacterial culture. The basic principles for deep infections are bridement of necrotic and infected tissue and healing by second area intension and antibiotics. Hand therapy is important.

Paralysis of the first dorsal interosseous muscle after external fixation of a distal radial fracture treated by transfer of the extensor indicis proprius tendon.

We describe a patient in whom the motor branch to the first dorsal interosseous muscle was injured by the pins of an fixator used to treat an unstable fracture of the distal radius. She was successfully treated by extensor indicis proprius transfer to the base of the proximal phalanx of the index finger.

[Ganglion--cysts of the hand and wrist]. / Ganglion--seneknude på hånd og håndled.

Ganglion cysts of the hand and wrist occur most frequently during the second through fourth decade and women are more frequently affected than men. Ganglion cysts may arise in any location in the hand and wrist but are usually adjacent to joins or tendons and sometimes bones. Patients often present with a history of an asymptomatic mass and many patients seek the advice of a physician because of the cosmetic appearance of the cyst. Observation is acceptable in most instances. Indication for operative treatment includes pain, interference with activity, nerve compression and ulceration of the mucous cysts.