Osteopetro-rickets: a new congenital bone disorder.

Two lethal mutations have been described in the rat: "osteopetrosis" (op) and "toothless" (tl). The op mutant can be cured by normal bone marrow infusion, while the tl mutant cannot. We report here additional data with regard to the tl mutant. The bone disease of the tl rat as in the op rat is associated with a precocious thymic atrophy, but bone lesions are quite different. In addition to classical osteopetrosis, the tl rat displays several features of rickets: broadening of the extremities of long bones, thickening of the epiphyseal plates, presence of osteoid areas. In addition, the persistence of embryonic characters, evidenced by high levels of alpha-fetoprotein, suggests that the developmental defect of bone is part of a more general process.

[Systematic study of the variations in mineral composition of different bones from various animals according to their localization]. / Etude systématique des variations de composition du constituant minéral de différents os de divers animaux suivant sa localisation.

X-ray diffraction techniques allow us to show that, in calcified tissues, phosphates resulting from a given formation process have the same ratio Ca/P for the bones at different subjects, providing these subjects are of the same kind and the same age. This ratio Ca/P depends on the bone formation process.

[Mineralization at the level of the calcified cartilage zone. Value and significance of the spicule of calcification]. / La minéralisation au niveau de la zone du cartilage calcifié. Valeur et signification du spicule de calcification.

The calcified cartilaginous spicule, generated in the zone of the calcified cartilage, is included in the primary metaphysis. It is generally admitted that the spicule had a homogeneous structure. Studies of structure and ultrastructure of the calcified spicule made the existence of two definitely different zones obvious: one at the periphery of the spicule, the other in the center. The process of mineralization, noticed on the cartilaginous column, reveals that vesicules are at the origin of mineralization of the peripheral zone and that mineralization of the central zone involves the granules of proteoglycans more particularly.

[Formation of the skeleton. VIII. Growth of a long bone: periostealization of the metaphysial bone]. / Sur la formation du squelette. VIII. Croissance d'un os long: sur la periostalisation de l'os métaphysaire

The growth of the diaphysis of a long bone is manifested in three distinct constituent parts: the bone periosteal collar and, at both ends, the two metaphyses. These grow on the epiphyseal plate side and at the other end, they are integrated into the periosteal bone collar. This integration involves changes in the periosteal bone as well as in the fibro-cellular-layer which surrounds it. All these modifications have been described as constitutuing "the periostealisation of metaphyseal bone".

[Formation of the skeleton. IX. Growth of a long bone: dynamics of diaphysial growth]. / Sur la formation du squelette. IX. Croissance d'un os long: sur la dynamique de la croissance diaphysaire

The diaphysis of a growing long bone is composed of three distinct parts: the bone periosteal collar and the two metaphyses. Each of these parts affects a separate radiographic, microradiographic and histologic appearance. By these means, it is possible to follow the growth and the increase of these parts and thus the relations which exist between them: all together they constitute the "dynamics of diaphyseal growth".

[Kinetic, radiographic, and histologic demonstration of the curing of congenital osteopetrosis in rats]. / Démonstration cinétique, radiographique et histologique de la guérison de l'ostéopétrose congéitale du rat

In the "op" rat congenital osteopetrosis is a lethal condition. The management of this disease can be achieved by a single injection of a marrow cell suspension from a normal donor or by temporary parabiosis with a normal Rat, the latter procedure being less efficient than the former according to kinetic, roentgenographical and histological examinations.

[Formation of the skeleton - growth of a long bone. Growth of the 3d metatarsal bone in the rat]. / Formation du squelette - croissance d'un os long. Sur la croissance du 3e métatarsien du rat

The authors have studied the longitudinal growth of the third metatarsal bone of the rat. This bone has only one epiphyseal plate at its distal extremity and none at its proximal one. Nevertheless it was demonstrated that the proximal extremity was responsible for 16% of the total longitudinal bone growth.