A spina-bifida-like condition was induced in 8 Macaca mulatta fetuses by intra-uterine lumbar laminectomy (L3-L5) followed by displacement of the spinal cord from the central canal. This condition was repaired in utero in 5 animals. A key feature of the repaired in utero in 5 animals. A key feature of the repair method was the use of allogeneic bone paste made from fetal bone particles suspended in an agar-thickened modified Dulbecco's medium. The bone paste was used to correct the bone deficit produced by the laminectomy. All of the monkey babies were delivered by cesarean section at near term (160-164 days of gestation). Neurological test on the neonates and subsequent morphological studies indicated that the in utero treated animals developed normally. In contrast, 3 control animals, which had the induced spinal dysraphism but were left untreated, showed severe spina-bifida-like abnormalities, including paraplegia, incontinence and somatosensory loss.

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The contribution of the basicranial synchondroses in the growth of neurocranial length and ontogenetic development of the cranial base were investigated. The study concentrated on the midsphenoidal synchondrosis and its delayed fusion in nonhuman primates when compared to man, and on the spheno-occipital synchondrosis. The mode and time of hsion of both growth centers were observed, and their role in the ontogenetic growth changes (flattening processes) of the cranial base were established. The chondrogenic ossification of midsphenoidal and spheno-occipital synchondroses was studied on 20 skulls of Macaca mulatta females, ranging in age from newborn specimens to those 24 months old. The technique of in vivo tetracycline bone labeling was used for histologic evaluation of the material. Different chondrogenic growth patterns were observed in both synchondroses. The endochondral activity of the spheno-occipital synchondrosis increased with age, from a nonactive narrow cartilaginous column in the neonatal specimen to a broad band with high chondrogenic ossification in the 24-month-old specimens. This growth center contributes to elongation of the posterior portion of the cranial base and is a secondary factor in its flexion.The midsphenoidal synchondrosis seems to be the primary factor in the mode of flexure of the cranial base in Macaques. This growth center is very active in the first ten months of life but later exhibits cessation of chondrogenic activity and long remains unfused. The first signs of fusion were observed as late as 72 months of age. At the same time, the continuous process of cranial base flattening showed the first signs of tapering off.The ontogenetic development of the cranial base and its flexion in human and other mammalian forms have been studied since pre-Darwinian days by comparative anatomical and anthropometric techniques. However, the empirical formulations of these descriptive studies were not explicit enough; the timing, mode and exact site at which the bending process in Homo and the flattening process in nonhuman primates occur remained obscure. Moreover, the role of cranial base synchondroses in these processes has not been clear. The significant role of the midsphenoidal synchondrosis (between postsphenoid and presphenoid) in the ontogenetic development of the cranial base as well as the phylogenetic Am. J. PHYS. ANTHROP., 37: 143-150.transformation of the skull in nonhuman primates has been largely neglected.The main basal synchondroses are spheno-occipital, midsphenoidal and sphenoethmoidal. However, these three growth centers are not involved in the same manner in the flexion phenomena of the cranial base.The role of the sphenoethmoidal synchondrosis in skull ontogeny seems minor in Macaca. Thus, this study is centered mainly around the spheno-occipital and midsphenoidal synchondroses.The purpose of this paper is to clarify the role of basicranial synchondroses in 1 This investigation was supported by USPHS grant HD 02281-05S1. 143 144MARIA MICHEJDA the ontogenetic devel...

The flexion of the cranial base and ontogenic migration of the foramen magnum in Macaca mulatto were investigated. Longitudinal cephalometric studies were carried out in infant and juvenile groups. Significant ontogenie changes of the cranial base were observed only in juvenile age group. The infant group did not exhibit any changes of the cranial base angle or migration of the foramen magnum. The diameter of the latter in infants exhibited small but statistically significant changes.

Hematopoietic stem cell transplantation has been increasingly used to replace a defective hematopoietic system and to treat various genetic defects as well as malignant diseases. However, the limitations of conventional bone marrow transplantation have stimulated an intense interest in exploring the use of alternative sources of hematopoietic stem cells, including peripheral blood mononuclear cells (PBMC) and cord blood (CB). A major investigative effort of our laboratory has been focused on evaluating fetal bone marrow (FBM) for transplantation. The current study compares and characterizes the functional and phenotypic characteristics of FBM, CB, adult bone marrow (ABM), and PBMC by clonogenicity assays, immunogenicity, and the quantification of progenitor cells. There was a striking difference in the proportion of CD34+ cells in FBM, ABM, PBMC, and CB (24.6%, 2.1%, 0.5%, and 2.0%, respectively). The clonogenic potential, as measured by colony forming unit in culture (CFU-C) assay, was significantly higher in FBM when compared with ABM, PBMC, and CB (202.5, 73.5, 40.8, and 65.5 colonies/10(5) cells, respectively). There was a significant decrease in proliferative responsiveness in mixed lymphocyte reaction (MLR) assay of FBM and CB compared with ABM and PBMC. These observations indicate that each source of hematopoietic stem cells has different intrinsic properties closely correlated with ontogenetic age that is a vital determinant for phenotypic characteristics, lineage commitments, immunogenicity, and proliferative potentials.