A multi-segment kinematic model of the foot with a novel definition of forefoot motion for use in clinical gait analysis during walking

A multi-segment kinematic model of the foot was developed for use in a gait analysis laboratory. The foot was divided into hindfoot, talus, midfoot and medial and lateral forefoot segments. Six functional joints were defined: ankle and subtalar joints, frontal and transverse plane motions of the hindfoot relative to midfoot, supination/pronation twist of the forefoot relative to midfoot and medial longitudinal arch height-to-length ratio. Twelve asymptomatic subjects were tested during barefoot walking with a six-camera optical stereometric system and auto-reflective markers organized in triads. Repeatability of the joint motions was tested using coefficients of multiple correlation. Ankle and subtalar joint motions and twisting of the forefoot were most repeatable. Hindfoot motions were least repeatable both within-subjects and between-subjects. Hindfoot and forefoot pronation in the frontal plane was found to coincide with dropping of the medial longitudinal arch between early to mid-stance, followed by supination and rising of the arch in late stance and swing phase. This multi-segment foot model addresses an unfortunate shortcoming in current gait analysis practice-the inability to measure motion within the foot. Such measurements are crucial if gait analysis is to remain relevant in the orthopaedic and rehabilitative treatment of the foot and ankle.     

Restricted cell/cell communication in the shoot apex ofSilene coeli-rosa during the transition to flowering is associated with a high mitotic index rather than with evocation

Summary Plants ofSilene coeli-rosa given 5 or more long days (LDs) flowered, even when the LDs were followed by 48 hours of darkness before their return to short days (SDs). The mitotic indices of shoot apices from induced plants shortly after induction were significantly higher than the indices of shoot apices from vegetative plants. Two major mitotic peaks were observed in the shoot apices of plants given 7 long days (LDs) on day 8. One coincided with that reported byFrancis andLyndon (1979).Cell to cell movement was tested in the shoot apices of vegetative and LD treated plants using probes with a molecular size of 749 daltons (fluorescein-hexaglycine) and 847 daltons (fluorescein-leucyl diglutamyl leucine). These probes showed some movement in the shoot apices of both short day (SD) and LD treated plants, but fluorescein-leucyl diglutamyl leucine was immobile in the induced apices of 7 LD plants on day 8 at time intervals which coincided with major mitotic activity in the shoot apex. Symplasmic restriction in the shoot apex was also observed in plants given 8 LDs (i.e., plants not returned to SDs on day 7).In plants that were placed in 48 hours of darkness after the 7 LD treatment or in plants given 5 LDs, there was no strong peak in the mitotic index, even though all these LD treatments resulted in 100% flowering. In such plants no symplasmic restriction was found in the shoot. Thus the symplasmic restriction on day 8 of 7 LD plants is associated with the high mitotic index, but neither of these phenomena is an essential part of the evocation process.Abbreviations F(Glu)₂ L-glutamylglutamic acid conjugated to fluorescein isothiocyanate isomer I (F-) - F(Gly)₆ F-hexaglycine - FLGGL F-leucyl-diglutamyl-leucine - F(PPG)₅ F-the pentamer (propyl-propyl glycine) - LD long day - LDs long days - SD short day - SDs short days