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Biomedical subjects

P J Atkinson

Publications and source records attributed to P J Atkinson.

8 recordsLinked to original sources
PubMed1979

Bone and soft tissue changes in paraplegic patients.

The loss of bone mineral in 66 paraplegic patients has been measured in the lower femoral shaft by scanning the leg with a beam of mono-energetic radiation from 241Am. The profile of the transmitted radiation was used to determine a parameter which was related to bone mass. The bone mass of paraplegic patients was significantly lower than normal. Persistent paralysis does not lead to a continued fall in bone mass, but once it has fallen, bone mass remains constant. Soft tissues also showed a muscle/fat ratio was lower than normal.

Adolescent↗
PubMed1979

Matrix and mineral changes in developing enamel.

An investigation of the changes taking place in the enamel and the enamel organ during enamel development has been carried out by analyzing small samples of tissue dissected from developing incisors of rat and bovine incisors. Observations showed that the synthesis of the enamel matrix and its subsequent loss were associated chiefly with a change in the major matrix components. This consisted of a selective loss of amelogenin components prior to secondary mineralization. Before this loss, some increase in the proportion of smaller molecular weight components suggested the possibility of limited breakdown. Even at the earliest stages examined, significant concentration of mineral ions was present. This increased steeply after most of the organic matrix had been removed. The Ca/P ratio of this mineral was constant throughout development. The concentration of minor inorganic ions (F, Mg and CO3) decreased as the tissue developed and a tendency was observed for certain ions (F, 32PO4) to penetrate and concentrate in the enamel, apparently as a consequence of the lost matrix being replaced by water, just prior to the steep increase in mineral content of the tissue.

Amelogenesis↗
PubMed1978

The role of the nursing administrator in collective bargaining.

There is little doubt that collective bargaining is here to stay in hospital nursing, and it adds a new dimension to the nursing administrator's area of responsibility. Careful planning and preparation for participation, trust and open communication, an attitude of acceptance, and a focus on the positive aspects of the negotiations will place the nursing administrator in an advantageous position in regard to collective bargaining in any practice setting.

Collective Bargaining↗
PubMed1976

The development and structure of the chimpanzee mandible.

The sites of growth and remodeling, and the associated changes in cortical bone structure, have been studied in the chimpanzee mandible and compared with those previously reported in the human and macaque mandibles. The location of the principal sites of growth, and the distribution of the areas of deposition and resorption in the ramus, were found to be similar in all three species. In the chimpanzee, unlike Man, the bone being deposited at the condyle, posterior border of the ramus and coronoid process was plexiform in nature, indicating very rapid growth. The pattern of remodeling in the mandibular body, on the other hand, showed marked species differences at the chin and on the submandibular lingual surface, which account for the contrasts seen in the adult morphology of these regions. Although the pattern of distribution of cortical densities differed from that of surface remodeling, the information they give is complementary in analysing bone growth. The densest regions were found to coincide with sites of consistent lamellar deposition, while the least dense regions were those where plexiform bone was formed. Areas where remodeling led to the greatest reorientation of bone tissue within the cortex showed the greatest disparity between the two patterns.

Age Determination by Teeth↗