The testing of an allometric center model of craniofacial growth.
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Animals↗
Biomedical subjects
H Vilmann
Publications and source records attributed to H Vilmann.
The growth of the first cervical vertebra in the rat.
With the help of in vivo marking with alizarin red S, the patterns of growth of the first cervical vertebra are demonstrated. Major parts of the developmental events which take place during growth (differential bone formation on the bone ends facing the synchondroses, closure of the dorsal synchondrosis at 14 days, closure of the ventral synchondroses at 35 to 40 days) may be explained by the influence that a capsular matrix exerts on its protecting and supporting skeletal unit. A demonstrated continued increase of the dorsoventral diameter of the bone is suggested to be an adjustive growth process related to the translative movements of foramen magnum, a topic that has been poorly understood and incompletely investigated.
Animals↗
Statistical testing of an allometric centered model of craniofacial growth.
An allometric centered model of craniofacial growth was tested by several computer-assisted statistical methods on the pure longitudinal growth data of twenty-four close-bred female rats and on cross-sectional human cranial growth data. The study demonstrated that such a model was heuristic and, being incapable of exact definition, was deemed inappropriate for further use in modeling of craniofacial skeletal growth. The necessity for vigorous testing of any hypothesis concerning the modeling of craniofacial growth is stressed.
Adolescent↗
Os penis of the rat. IV. The proximal growth cartilage.
Histomorphological and histochemical aspects of the proximal cartilage of os penis and its surrounding perichondrium in 60 rats aged between 1 and 100 days are described. Comparisons at 11-14 days with the mandibular condylar cartilage reveal a slight difference in their general morphological composition. The developmental changes which take place in the os penis cartilage reveal histomorphologic events, some of which may be brought into agreement with previous observations of patterns of transformations of the bone. Observations on an age-dependent morphological appearance of the area adjacent to the proximal surface of the cartilage suggest certain agreements between the mandibular angular cartilage and the os penis cartilage. The study of phosphomonoesterases in the os penis cartilage and its perichondrium reveals significant, unexplained differences in the distribution of alkaline phosphatase between this cartilage and the mandibular condylar cartilage.
Acid Phosphatase↗
Analytical description of growth.
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Animals↗
The mandibular angular cartilage in the rat.
Histomorphological and histochemical aspects of the mandibular angular cartilage and its surrounding perichondrium are described from a material consisting of 46 rats aged between 1 and 56 days. Comparisons at 11-13 days with mandibular condylar cartilage reveal a marked concordance in their general composition. However, certain differences in extent of the subzones constituting the cartilage are present. These differences are suggested to express differences in growth rates between the structures. The study of the age changes which take place in the mandibular angular cartilage reveals an age-related change in direction of the muscles attached to the medially and laterally facing surfaces of the structure in combination with a change in direction of the connective tissue covering its posterior part. Such changes might be indications of changes in direction of the tensional forces acting on the cartilage. Ultimately, they might be related to the limited temporal maintenance of the structure.
Age Factors↗
Neuro-skeletal topology of the primate basicranium: its implications for the "fetalization hypothesis".
The data above, and the literature reviewed, demonstrate that in 4 significant morphological characteristics the neuro-skeletal topology of the human basicranial regions is unique, and does not resemble that of any extant non-human primate at any fetal or postnatal age. These characteristics are: 1. the shape of the cranial base; 2. the composition of the anterior and posterior portions of that base; 3. the extent, or degree, of basicranial flexion; and 4. the extent, or degree, of brain flexion. On these bases, the craniological implications of Bolk's fetalization hypothesis cannot be supported.
Animals↗
Os penis of the rat. III. Formation and growth of the bone.
In a series of studies of morphology and morphogenesis of os penis in the rat, the present study deals with initial formation and growth of the bone. Os penis in the rat develops at 1 day p.n. as a membrane bone. It becomes associated with a proximally situated growth cartilage at 3-4 days. Until 10 days it increases in width by periosteal apposition on all surfaces. After 10 days the growth in width takes place by differential processes of apposition and resorption. Results from vital staining with alizarin red S of bones at different ages indicate that os penis during its growth becomes transformed in a ventral direction in the period between 10 and 35 days, while it after that age is transformed in a dorsal direction. No reasonable explanation on this phenomenon is offered. However, the observed periods of time of uniform growth pattern are comparable to time periods of uniform growth patterns of a number of cranial bones.
Animals↗
Methods for demonstration of enzyme activity in muscle fibres at the muscle/bone interface in demineralized tissue.
A method for demonstration of activity for ATPase and various oxidative enzymes (succinic dehydrogenase, alpha-glycerophosphate dehydrogenase, and lactic dehydrogenase) in muscle/bone sections of fixed and demineralized tissue has been developed. It was found that it is possible to preserve considerable amounts of the above mentioned enzymes in the muscle fibres at the muscle/bone interfaces. The best results were obtained after 20 min fixation, and 2-3 weeks of storage in MgNa2EDTA containing media. As the same technique previously has been used to describe patterns of resorption and deposition with the aid of a mapping of presence of phosphomonoesterases on bone surfaces, the method may be used to study possible biochemical interactions between bone and muscle tissue at the muscle/bone interface.
Adenosine Triphosphatases↗
Space-time presentations of the shell of the bivalved mollusk Cardium edule.
In a recent article the concept of studying craniofacial growth in space-time was introduced. The possibilities of carrying out such studies were demonstrated with the aid of some generalized shell of a bivalved mollusk. In this study presentations of space-time models of a real biologic model, the shell of the bivalved mollusk Cardium edule, have been constructed. Quantitative expressions of paths in space-time of anatomic and material points have been elaborated. A further analysis has shown that a number of the space-time presentations may represent biologic reality. They may be used for comparisons with presentations of skull models and may represent a tool for the better understanding of results from other studies.
Animals↗
Studies on orthocephalization. VII. Behavior of the rat cranial frame in the period between 1 day before birth to 14 days after birth.
The positional stability of the zygomatic arch of the rat skull in relation to the parietal bone, the basisphenoid bone and the length axis of the skull, as previously demonstrated in rats older than 14 days, does not exist to the same degree in younger rats. These conclusions have been drawn from a study of a sample of rats, aged 0, 4, 7 and 14 days. These 4 groups of rats have been x-rayed after sacrifice, and from the x-ray photographs, quantitative expressions of angular values between the mentioned structures have been obtained. The most important result is, however, considered to be, that a full description of the behavior of the external cranial frame of the rat skull is now available for further studies on the process of orthocephalization.
Aging↗
Studies on orthocephalization. 6. Flexions of the rat head in the period between 1 day before gestation and 14 days after gestation.
The present paper considers the significance of a variety of cranial flexions in the process of orthocephalization of the rat skull between 1 day before birth to 14 days after birth. The study is based on a sample of 95 albino rats divided into 5 age groups (1 day before birth - 0 days - 4 days - 7 days - 14 days after birth), who have been sacrificed and x-rayed with subsequent analysis of the photos obtained. Before x-raying, the rat heads have been treated with AgNO3 to improve the contrast of the bone images on the x-ray photos. In the period studied, the angle between the cranial base and the facial part of the skull becomes considerably more obtuse, i.e. the skull becomes considerably more orthocranial. As compared to the changes that have been shown in 14...60 days old rats, the changes in the early period are much more marked. The cranial vault in the young rats studied, also becomes flatter and more square, due to changes between the individual bones of the vault. This flattening is a significant part of the straightening of the rat skull as a whole, i.e. of the process of orthocephalization. In 14...60 days old rats the simultaneous size increase which primarily takes place in the bones of the facial skull reinforces an impression of marked orthocephalization. In the young rats of the present study, the size increase takes place both in the facial and in the cerebral part of the skull. The result of this leaves an impression of only moderate angular changes, although the changes are much more pronounced than in the older rats.
Age Factors↗
The allometric center. The biological basis of an analytical model of craniofacial growth.
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Animals↗
Space, time, and space-time in craniofacial growth.
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Animals↗
Studies on orthocephalization. IV. Differential growth of the sphenooccipital synchondosis in the rat.
The growth of the bone ends articulating through the sphenooccipital synchondrosis in the rat occurs differentially. Considerably more bone is during growth formed in the pharyngeal part of the anterior end of the basioccipital bone than in the cerebral part. The same conditions hold good for the posterior end of the basisphenoid bone, although to a less degree. These conclusions have been reached by studying the distribution of alkaline phosphatase reaction in the perichondrium covering the sphenooccipital synchondrosis. Extension of reaction to this enzyme in perichondria has previously been shown to be a measure of growth rate. Sections of the sphenooccipital synchondrosis from 10 rats 10 days ago, incubated for reactions to alkaline phosphatase have formed the basis of the study. Quantitative expressions of the extension of enzymatic reaction have been collected. Statistical treatment of these data have resulted in the above mentioned conclusions.
Alkaline Phosphatase↗
Studies on orthocephalization. V. peripheral positional stability of the rat cranial frame in the period between 14 and 150 days.
In the period from 14 to 150 days, the zygomatic arch of the rat skull possesses a marked positional stability in relation to the parietal bone, the basisphenoid bone and the length axis of the skull. These conclusions have been drawn from a study of 27 male rats, X-rayed at regular intervals between 14 and 150 days. From the X-ray photos, quantitative expressions of angular values between the mentioned structures have been obtained. The significance of the observations is discussed. It is emphasized that the demonstrated stability of these structural components of the rat skull during growth is in marked contrast to the extent of movements which take place between other parts of the skull during orthocephalization.
Animals↗
Patterns of distribution of phosphomono-esterases on surfaces of demineralized bone.
Decalcification over short periods (5 days) with MnNa2 EDTA, MgNa2 EDTA and EGTA according to a method described in the present paper, creates sections of high quality with simultaneous good preservation of phosphomonoesterases on bone surfaces. In fact, the enzyme distribution seems to be comparable to that obtained by using undecalcified sections. Na2 EDTA creates, on the other hand, poor preservation of alkaline phosphatase probably due to the fact that this chelate contrary to the other chelates removes the essential metal from the protein, leaving an unstable enzyme molecule which undergoes denaturation. Decalcification over longer periods (15 days) does not influence the pattern of distribution of acid phosphatase, whereas the alkaline phosphatase reaction becomes depressed in certain surface areas. The significance of this differential distribution is discussed. It might be an indication of differential processes of bone transformations in such a way that bone surfaces corresponding to areas of enzyme reactions are depository whereas bone surfaces corresponding to areas of lack of enzyme reaction are resorptive. New experimental designs are, however, necessary before the phenomenon is fully perceived. Two different coupling agents were used in connexion with the demonstration of acid phosphatase reaction. When HPR was used as the coupler the final enzyme distribution coincided with that usually described in the literature, i.e., strong reaction of cells adjacent to resorptive surfaces and weak reaction of cells adjacent to depository surfaces. When, however, Fast dark blue R was used all surface cells reacted markedly. This method also revealed certain cell types with nuclear reaction.
Acid Phosphatase↗
The significance of a differential distribution of phosphomonoesterases on bone surfaces after prolonged demineralization.
An observed differential distribution of alkaline and acid phosphatase on the surfaces of growing bones may serve to describe transformative processes of bone growth. This conclusion has been reached by comparing the distribution of the two enzymes on the surfaces of fibulae from young rats with the patterns of apposition and resorption on the periosteal surfaces of this bone, revealed by in vivo staining with alizarin red S. Presence of reaction to acid phosphatase is, as shown before, an indication of resorptive surfaces, while the presence of reaction to alkaline phosphatase is an indication of depository surfaces.
Acid Phosphatase↗