Biomedical subjects

D Roze

Publications and source records attributed to D Roze.

3 recordsLinked to original sources

PubMed2002

Preliminary results and evidence of early regeneration in inferior alveolar nerve fibers.

Inferior alveolar nerve (IAN) damage can occur in trauma, cyst enucleation, sagittal split osteotomy or third molar removal, and the consequences are a loss of sensation to the mandibular teeth, gingiva and lower lip. Because of its anatomical position in a bony canal, IAN suture is rarely evoked. The aim of this study was to demonstrate the reality of IAN regeneration by using electrophysiological and histological methods after experimental section and suture of this nerve in rabbits. Nine adult female animals were used for the experiments. Six months after section and suturing using 10.0 nylon with a conventional technique, electrical stimulation of the nerve was performed to record electrophysiological activity. Each rabbit was its own reference. In each case, an action potential was recorded after microsurgical repair and definitively suppressed by section of the nerve. Morphometric analysis showed a decrease in the number of nerve fibers in the operated nerve versus the control nerve. The histological study showed an increase in nerve fibers with a cross-sectional area of 19-36 and 37-73 micro m(2) and a decrease in the smaller fibers (2-4 and 5-7 micro m(2)). This preliminary study confirms the possibility of nerve regeneration in rabbits 6 months after section and conventional suturing.

Animals↗

PubMed2001

Cooperation and conflict in the evolution of multicellularity.

Multicellular organisms probably originated as groups of cells formed in several ways, including cell proliferation from a group of founder cells and aggregation. Cooperation among cells benefits the group, but may be costly (altruistic) or beneficial (synergistic) to individual cooperating cells. In this paper, we study conflict mediation, the process by which genetic modifiers evolve that enhance cooperation by altering the parameters of development or rules of formation of cell groups. We are particularly interested in the conditions under which these modifiers lead to a new higher-level unit of selection with increased cooperation among group members and heritable variation in fitness at the group level. By sculpting the fitness variation and opportunity for selection at the two levels, conflict modifiers create new functions at the organism level. An organism is more than a group of cooperating cells related by common descent; organisms require adaptations that regulate conflict within. Otherwise their continued evolution is frustrated by the creation of within-organism variation and conflict between levels of selection. The evolution of conflict modifiers is a necessary prerequisite to the emergence of individuality and the continued well being of the organism. Conflict leads--through the evolution of adaptations that reduce i--to greater individuality and harmony for the organism.

Animals↗

PubMed1997

Transitions in individuality.

The evolution of multicellular organisms is the premier example of the integration of lower levels into a single, higher-level individual. Explaining the evolutionary transition from single cells to multicellular organisms is a major challenge for evolutionary theory. We provide an explicit two locus genetic framework for understanding this transition in terms of the increase of cooperation among cells and the regulation of conflict within the emerging organism. Heritability of fitness and individuality at the new level emerge as a result of the evolution of organismal functions that restrict the opportunity for conflict within and ensure cooperation among cells. Conflict leads, through the evolution of adaptations that reduce it, to greater individuality and harmony for the organism.

Adaptation, Physiological↗