Biomedical subjects

B G Sarnat

Publications and source records attributed to B G Sarnat.

At least 37 records · Page 2Linked to original sources

PubMed1980

Orbital volume in young and adult rabbits.

One hundred and ninety-nine postnatal volumetric determinations were made of orbits from 159 young and adult rabbits (64 New Zealand, 95 Dutch) by means either of linear measurements or of removable permanent elastic rubber base imprints. The volumes were calculated from the weights and specific gravities of the orbital imprints. Orbital volume in the New Zealand albino rabbits ranged from 0.7 ml at 14 days to 7.8 ml at 302 days of age. By about 180 days of age orbital volume had reached about 6.5 ml, near its maximum, and was about nine times the size at 14 days of age. Orbital volume in the Dutch rabbits ranged from 3.6 ml at 98 days to 5.8 ml at 540 days of age and were smaller than the New Zealand rabbit orbital volumes. By about 180 days the Dutch rabbit orbital volume had reached its maximum of about 5 ml and was about 25 percent larger than at 100 days of age. Values of orbital volume for the Dutch rabbits correlated noticeably with weight.

Age Factors↗

PubMed1980

Eye volume in young and adult rabbits.

Volumetric determinations were made by means of linear measurements and permanent stone models of 98 fresh eyes from 84 Dutch rabbits ranging from 15 to 540 days of age. The relationship of eye volume to age was evaluated. At 15 days of age, the eye volume is about 20% of adult size, at 100 days of age about two thirds of adult size, at 180 days of age about 85% of adult size, which is reached at about 300 days of age.

Aging↗

PubMed1979

Adult rabbit eye and orbital volumes after periodic intrabulbar injections of silicone.

The intent of this experiment was to determine whether periodic injections of silicone into the adult rabbit eye would alter the volume of the eye and/or orbit. This procedure in growing rabbits had resulted in increased volumes of both the eye and orbit. Nineteen 13-month-old (adult) rabbits were used. In 12 animals silicone was injected into one eye but not the opposite one. No silicone was injected into the eyes of 7 untreated rabbits. In a 9-week period the total amount of ten silicone injections into each treated eye ranged from 5.7 to 7.6 ml. 1 week after the last injection each eye was enucleated, an impression made immediately, and a permanent model subsequently developed. From this the volume was determined. A t test was performed on the mean differences of the eye and orbital volumes of the injected and noninjected sides for each group. No significant differences was found. It was concluded within the limitations of this experiment that there was no evidence that periodic intrabulbar injection of silicone into the adult rabbit eye altered its volume. Thus, this procedure also did not alter orbital volume. In contrast, in the growing rabbit both eye and orbital volume had increased significantly after intrabulbar injection of silicone.

Animals↗

PubMed1979

Experimental and clinical postnatal craniofacial skeletal changes.

An understanding of normal and abnormal postnatal skeletal changes can aid in the prevention, early recognition and proper surgical treatment of craniofacial deformities. Research findings may have important implications and applications in relation not only to the basic problem of change of bone form but also to the clinical problems of craniofacial operations. Precise analogies, however, should not be made between animals and human beings. Change of the craniofacial skeleton, a three-dimensional mosaic of bones and cavities, is a result of the synchronous co-ordination of the differential activities at various sites. The dynamics of normal and abnormal postnatal growth and change of the craniofacial skeletal system are a fascinating, complex, incomplete chapter in the field of biology.

Adult↗

PubMed1978

Orbital volume after enucleation and eye volume in the adult rabbit.

Of 21 mature, fully grown Dutch rabbits, seven were controls separated into two groups in which eye and orbital volumes were determined at 10 and at 18 months of age respectively. In the 14 remaining rabbits, enucleation of one eye was done at 10 months of age. Immediately afterward the eye volume was determined. These animals were killed at 18 months of age at which time the volumes of the remaining eye and of both orbits were determined. Within the limits of this preliminary experiment the following were noted. The mean eye volume was slightly greater at 18 than at 10 months of age. This was statistically significant. After enucleation of the eye at 10 months of age orbital volume of that side was similar to the opposite side at 18 months of age in the male rabbits. In the female rabbits there was a small significant statistical difference. The conclusions however, are that in the Dutch rabbit there is not a meaningful clinical volumetric difference in either the eye from 10 to 18 months of age or the orbit from 10 to 18 months of age with or without enucleation at 10 months of age.

Animals↗

PubMed1978

Differential craniofacial skeletal changes after postnatal experimental surgery in young and adult animals.

To find answers to the many questions about abnormal postnatal growth and change of the craniofacial skeleton, a series of surgical experiments was carried out in both young and adult animals. The purpose of this review is to relate this information to basic ideas about bone change and some local factors which may or may not affect skeletal changes. No gross regional deformity was noted after resection of sutures in young animals. The growth of bone at sutures was secondary or compensatory to other factors. In young animals, increase in size of the nasal or orbital cavities decelerated considerably after resection of either nasal septum or orbital tissues. With an increase in volume of orbital contents, orbital volume increased. These prominent gross changes in young animals were not noted in adult animals after resection of nasal septum, enucleation of the eye, or intrabulbar injection of silicone. After unilateral resection of the mandibular condyle in both young and adult monkeys, an extreme unilateral facial skeletal deformity developed. The important factor apparently was loss of integrity of the temporomandibular joint rather than loss of a growth site. The craniofacial skeleton, a three-dimensional mosaic of bones and cavities, develops as a result of the synchronous coordination of the differential activities at various sites. The dynamics of the growth and change are a fascinating, complex, incomplete chapter of biology. An understanding of factors that may or may not influence the craniofacial skeleton in both young and adult animals can aid diagnosis and surgical treatment.

Age Factors↗

PubMed1978

Growth pattern of the rabbit nasal bone region. A combined serial gross and radiographic study with metallic implants.

Two radiopaque implants were inserted into each left and right nasal bone in 5 female rabbits. Ventrodorsal cephalometric radiographs were then taken in a specially designed head-holder at 6 and 16 weeks of age. From these radiographs separate tracings were made on matte acetate paper of the left and right nasal bone regions including the radiopaque implants. Since the implants maintained the same relationship to each other in each nasal bone, they served as stable reference sites. The markers of the 16-week tracing were superposed on the markers of the 6-week tracing. The difference in the two established outlines represented the changes in size and shape in two dimensions that had occurred during the 10-week period. Our purpose was to determine the relative growth activity at several borders. The mean increase was 6.79 mm at the proximal (posterior) border, 6.19 mm at the distal (anterior) border, 2.73 mm at the lateral border, 1.22 mm at the medial border. Thus, growth at the proximal and the distal borders was about the same and about twice that of the lateral border and about 5 times that of the medial border.

Age Factors↗

PubMed1977

Adult monkey coronoid process after resection of trigeminal nerve motor root.

A smaller or absent coronoid process has been reported, by some investigators but not by others, in growing animals following resection of the temporalis muscle. The trauma of resection, altered function, hemorrhage, scar tissue, and changes in vascularity may have influenced the results. The purpose of this experiment was to observe in adult Macaca mulatta the fully grown coronoid process after decreasing or eliminating neurofunctional activity of the temporalis muscle unilaterally without the trauma of local resection. In two males and three females the motor root of the trigeminal nerve which innervates the temporalis muscle was resected intracranially. In three control animals of both sexes the same surgical procedure was performed except for resection of the nerve. At postmortem, one year later, the temporalis muscle mass was atrophic on the resected side. There were no significant morphological differences, however, between the right and left sides of the mandible, including the coronoid process, regardless of which motor root of the fifth nerve had been resected, which side had been sham-operated, or sex. An extensive deposit of calculus on the buccal surfaces of the teeth on the operated nerve side was a consistent, conspicuous finding.

Animals↗

PubMed1977

Growth pattern of the rabbit snout dorsum: a serial cephalometric radiographic study with radiopaque implants.

Two radiopaque implants were inserted into each (left and right) frontal bone in five female rabbits. Ventrodorsal cephalometric radiographs were then taken in a specially designed head holder at 6 and 16 weeks of age. From these radiographs separate tracings were made on matte acetate paper of the left and right snout including the radiopaque implants. Since the implants maintained the same relationship to each other in each frontal bone, they served as stable reference sites. The markers of the 16 weeks tracing were superposed on the markers of the 6 weeks tracing. The difference in the two established outlines of the snout represented the changes in size and shape in two dimensions that had occurred during the 10 weeks period. The mean increase was 17.91 mm at the distal (anterior) border, 4.95 mm at the lateral border, and 1.22 mm at the medial border. Thus, growth at the lateral border of the snout was about 3 1/2 times that of the lateral border.

Animals↗

PubMed1974