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Various studies suggest impact trauma may initially soften cartilage, damage subchondral bone, or a combination thereof. The initial damages are commonly thought due to excessive contact pressure generated on cartilage and the underlying bone. The objective of this research was to develop a small animal model for studying post-traumatic OA and to correlate contact pressure with tissue damage. Blunt insult was graded by dropping a rigid mass onto the hyperflexed hind limb of rabbits. Contact pressure in the patello-femoral joint was measured with pressure sensitive film. One, 3, 6, and 14 days later the animals were euthanized. Damage to cartilage and the underlying bone was assessed visually and in microscopic sections. Indentation experiments were performed on the patellar cartilage with a rigid, flat probe. Contact pressures were nonuniform over the articular surfaces and a high frequency of surface fissures were generated on the lateral facet in severe insults. The appearance of surface fissures correlated better with the magnitude of contact pressure gradients in the damage zone than the magnitude of contact pressures on the facet, per se. Blunt trauma causing surface fissures resulted in a measurable degree of softening in the patellar cartilage, especially close to the defects. Surgical intervention of the joint to insert pressure sensitive film, however, also resulted in significant softening of the cartilage.

We discuss the taxonomy of oak gallwasps (Hymenoptera: Cynipidae: Cynipini) whose lifecycle involves only Palaearctic oaks (Quercus subgen. Quercus) in the section Cerris. Recent phylogenetic reconstructions support a deep split between such Cerris-associated species in the genera Aphelonyx, Dryocosmus, Plagiotrochus, Neuroterus, Pseudoneuroterus and species and genera associated with oaks in the section Quercus sensu stricto. We reappraise the generic limits of the Cerris-associated genera, proposing new limits for Dryocosmus, Pseudoneuroterus and Neuroterus, establishing a new genus Cerroneuroterus, elevating Latuspina to a genus level, reestablishing the genera Chilaspis and Trichagalma and proposed new species name combinations. We provide a new key to oak gallwasp genera of the Palaearctic and keys to all species of genera associated with Cerris section oaks. We describe five new species, Aphelonyx kordestanica, Trichagalma formosana, Dryocosmus jungalii, Pseudoneuroterus mazandarani, and P. nichollsi.

Two types of lunate were recognized in the midcarpal joint. Type I lunate has no facet articulation with the hamate, and Type II lunate has a facet articulation with the hamate. The purposes of this study are to estimate the biomechanical contribution of Type II lunate for Kienböck's disease, and to elucidate the change of the contact surface between the lunate and hamate during radial and ulnar deviation for both Type I and Type II. Twenty-four contralateral unaffected wrists with Kienböck's disease were used for the first purpose. The radiographic force analysis was performed with a modified two-dimensional rigid-body spring model computer-simulation technique. Six wrists of volunteers (3 of Type I and 3 of Type II lunates) were used for the second purpose. Dynamic examination on lunohamate joint was carried out using magnetic resonance imaging. The force distribution between the radius and Type II lunate was greater than that between the radius and Type I lunate statistically. Furthermore, the impingement of articular cartilages between Type II lunate and hamate was observed in ulnar deviation on dynamic study. These results suggest that Type II lunate was one of the anatomical risk factors for Kienböck's disease.

A new gall-inducing species of the inquiline tribe Synergini (Hymenoptera: Cynipidae), Synergus itoensis Abe, Ide & Wachi, sp. nov., from Japan is described. The morphological features of the adult clearly indicate that this new species is assigned to the genus Synergus Hartig, 1840, and members of Synergini have all been known as inquilines to date. Field observation showed that adult emergence of this gall wasp from acorns of the evergreen oak, Quercus (Cyclobalanopsis) glauca Thunberg, on the ground is well synchronized with the rapid growth period of fresh acorns in late summer. A rearing experiment demonstrated gall induction by S. itoensis in the seed coat of the acorn of Q. (C.) glauca under field conditions. Moreover, the occurrence of arrhenotoky in this gall wasp and lack of a significant effect of gall induction on acorn size were indicated. Judging from the inconsistency of biological and morphological features in S. itoensis, gall-inducing ability might have been regained within Synergini. The advantages and disadvantages of gall induction in acorns are discussed.

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