[The diagnosis of patellar luxation in small animals]. / Die Diagnostik der Patellarluxation des Kleintieres.

A standard diagnostic procedure for patellar luxation is described. It is based upon the patellar luxations grade 1 to 4, which have been published before, and contains additional definitions in terms of the animals positioning toward the examiner.

[Traumatic elbow joint luxation in the dog and cat: perioperative findings]. / Die traumatische Ellbogengelenkluxation bei Hund und Katze: perioperative Befunde.

Thirty-eight cases (24 dogs, 14 cats) of elbow luxation were reviewed. Seventeen surgical treatments were necessary either after conservative reduction (14) or because conservative reduction was not possible (3). Medial instability of the elbow joint due to medial collateral ligamental damage or avulsion of the origin of the medial collateral ligament were the major indication for surgery. The type and frequency of perioperative lesions as well as their therapeutical and prognostical relevance are described.

[Clinical and radiologic evaluation of the integrity of medial and lateral collateral ligaments of the elbow in dogs]. / Klinische und radiologische Evaluation der Integrität des medialen und lateralen Kollateralbandes des Ellbogens beim Hund.

Closed reduction is the best therapy in most cases of luxation of the elbow. Clinical retrospective studies showed the presence of arthrosis in 50% of the cases treated with closed reduction (Meyer-Lindenberg et al., 1991) and persisting medial instability after the reduction in more than 50% of the cases. In the present study, the biomechanic of both medial and lateral collateral ligaments was analyzed after selective severing of those ligaments. Severing of the medial collateral ligament led to an average increase of the pronation of 30 degrees with the presence of crepitus on the lateral aspect of the elbow during passive motion. The medial instability of the elbow could be evidenced clinically as well as radiographically. Severing of the lateral collateral ligament resulted in an average increase of the supination of 15 degrees. No evidence of subluxation could be diagnosed using palpation or radiology. Craniocaudal stressed radiographic views of the elbow in pronation are the most helpful to document damages of the collateral ligaments of the elbow.

Comparison of the feeding responses to bacterial lipopolysaccharide and interleukin-1 beta.

To further investigate the idea that endogenous interleukin-1 plays a major role in the anorectic effect of bacterial lipopolysaccharide (LPS), feeding responses to recombinant human interleukin-1 beta (rhIL-1 beta) and LPS, as well as crosstolerance or -sensitization between both compounds, were investigated in rats. Intraperitoneally (IP) injected paracetamol (50 mg/kg body weight = b.wt.) markedly attenuated the anorectic effect of rhIL-1 beta (50,000 LAF units/kg b.wt., IP), but was clearly less effective in attenuating the anorectic effect of LPS (100 micrograms/kg b.wt., IP). As in previous experiments of ours, repeated IP injections of rhIL-1 beta (three injections of 50,000 LAF units/kg b.wt. on experimental days 1, 4, and 10) resulted in sensitization to the anorectic effect rhIL-1 beta, whereas repeated IP injections of LPS (three injections of 100 micrograms/kg b.wt. every second day) resulted in LPS-tolerance. Sensitization to the anorectic effect of rhIL-1 beta did not affect the anorectic response to LPS. Likewise, LPS-tolerance did not alter the anorectic response to rhIL-1 beta. RhIL-1 beta suppressed feeding by reducing meal frequency and meal size. In contrast, the anorectic effect of LPS was due entirely to a reduction of meal frequency. The results indicate that rhIL-1 beta and LPS do not affect feeding through exactly the same mechanism.

Enhancement or loss of the hypophagic effect of interleukin-1 upon chronic administration.

To further characterize the effect of interleukin-1 on food intake, we tested whether a tolerance to the hypophagic effect of recombinant human interleukin-1 beta (rhIL-1 beta) develops with repeated injections or continuous infusion in rats. Daily intraperitoneal (IP) injections of rhIL-1 beta (25,000 LAF units/kg b.wt.) for 4 days did not result in tolerance to rhIL-1 beta's hypophagic effect. The hypophagic effect of the same dose of rhIL-1 beta actually increased if injections were given every second day, when the hypophagic effect of the preceding injection had subsided. A dose of rhIL-1 beta that usually did not affect food intake (5000 LAF units/kg b.wt.) reduced food intake if injected repeatedly. Continuous infusion of rhIL-1 beta (25,000 LAF units/kg b.wt/day) via IP-implanted osmotic minipumps caused a strong initial suppression of feeding followed by the development of tolerance to the hypophagic effect of the infused rhIL-1 beta. Nevertheless, hypophagia caused by a subsequent IP injection of rhIL-1 beta (25,000 LAF units/kg b.wt.) was enhanced. As specific antibodies to rhIL-1 beta could be detected in sera of only three of 11 rhIL-1 beta-infused rats, the observed tolerance was probably not due to a humoral immune response. The results demonstrate that, dependent on test conditions, chronic administration of rhIL-1 beta in the rat can lead to an enhancement or to a loss of its hypophagic effect. The reasons for this difference remain unclear.

Differential feeding responses to bacterial lipopolysaccharide and muramyl dipeptide.

The present study was designed to test whether a tolerance to the hypophagic effects of bacterial lipopolysaccharide (LPS) and muramyl dipeptide (MDP) develops with repeated injections in rats and whether a relationship between the hypophagic effects of both compounds exists. Only the first of three subsequent intraperitoneal injection of LPS (100 micrograms/kg body wt each), given every 2nd day, led to a significant reduction of food intake. In contrast, MDP (1.6 mg/kg body wt) did not lose its hypophagic effect with four subsequent intraperitoneal injections. Furthermore, the LPS tolerance did not alter the hypophagic response to subsequently injected MDP. Likewise, MDP pretreatment did not alter the hypophagic response to LPS. Doses of MDP and LPS that were individually below the threshold for a reliable reduction of food intake (0.4 mg MDP/kg body wt + 25 micrograms LPS/kg body wt) reduced food intake synergistically when injected together. The hypophagia produced by combined injections of MDP plus LPS slowly diminished with repeated injections. The results indicate that separate but interacting mechanisms are involved in the feeding responses to MDP and LPS. The observed synergism between MDP and LPS suggests a synergistic role of bacterial muramyl peptides and LPS in the anorexia during bacterial infections.