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Biomedical subjects

B G Sarnat

Publications and source records attributed to B G Sarnat.

At least 19 recordsLinked to original sources
PubMed2001

Effects and noneffects of personal environmental experimentation on postnatal craniofacial growth.

Genetic makeup, as well as various environmental factors, such as gravity, temperature, disease, trauma, inflammation, radiation, and chemicals, may affect skeletal growth sites and centers, thereby causing faulty growth of bone(s). The degree of the subsequent deformity will depend not only on the type, intensity, extent, and chronology of the noxious agent but also on the site and its particular susceptibility and growth activity. Over the years, I conceived, designed, initiated, and carried out a series of experiments in regard to bone(s), in both young and adult animals. Eventually, I directed my efforts principally toward local surgical experimentation as it related to both normal and abnormal gross postnatal craniofacial growth. Because of the wide variety of different structures, their interrelated individualities, and the challenges presented in both its richness of sites of growth and complexity, the skull proved to be a most unusual source of study. The purpose of this selective, organized, and limited review, analysis, and summary of personally conducted experiments is to relate certain aspects of growth with change and nonchange to age, sites, rates, factors, and mechanisms. In many instances, there are correlations between basic research findings and clinical practice. There is no such similar report in the literature. This retrospective study brings it all together.

Animals↗
PubMed1997

A retrospective of personal craniofaciodental research and clinical practice.

Recent reports have emphasized the need for further knowledge about the growth of bone(s). This is particularly true because an understanding of the normal and abnormal growth of bone(s) forms the basis of early recognition and appropriate treatment of many deformities. It is less well appreciated, however, that the findings in the abnormal may be employed to test and extend our knowledge of the normal. Genetic makeup, as well as various types of diseases and injuries such as trauma, inflammation, radiation, and chemicals, may affect skeletal growth sites and centers, thereby causing faulty growth of bone(s). The degree of the subsequent deformity will depend not only on the type, intensity, extent, and chronology of the noxious agent but also on the site and its particular susceptibility and growth activity. The problem of treatment of craniofaciodental deformities is a difficult one. Over the years, I conceived, designed, initiated, and carried out a series of experiments in regard to bone(s), teeth, and cartilage in both young and adult animals (turtles, rats, gophers, lagomorphs, pigs, dogs, and monkeys). Eventually, I directed my efforts principally toward local surgical experimentation as it related to both normal and abnormal gross postnatal craniofaciodental growth. Because of the wide variety of different structures, their interrelated individualities, and the challenges presented in both its richness of sites of growth and complexity, the skull proved to be a most unusual source of study. The purpose of this selective, organized, and limited review, analysis, and summary of personally conducted experiments is to relate certain aspects of differential growth and change and nonchange to age, sites, rates, factors, and mechanisms. In many instances, correlations are made between research findings and clinical practice. No such similar report as this was found in the literature. This retrospective study brings it all together.

Animals↗
PubMed1997

Some methods of assessing postnatal craniofaciodental growth: a retrospective of personal research.

OBJECTIVE: The purposes of this review and summary are to evaluate several selected significant clinical and basic science methods utilized to assess growth of bone(s), and in particular craniofaciodental growth: appositional and resorptive (bone), endochondral (bones), and sutural (bones). This personal retrospective report includes in part anthropometry, impressions and casts, vital markers, histology, radiopaque implant markers with and without serial cephalometric radiographs, and autoradiography. Knowledge obtained from the use of these various methods on rats, ground squirrels, rabbits, pigs, dogs, monkeys, and humans has contributed to a deeper and more fundamental understanding of both the processes and roles that craniofaciodental biology plays in the advancement not only of basic biology but also of craniofacial surgery. Growth and development of the skeletal system has an important role in determining body form. The dynamics of growth of bones is a complicated process. A number of different methods have been described by which growth of bones can be evaluated on both a quantitative and qualitative basis. No single method, however, should be relied on, because although it may have certain definite advantages, it also has its limitations. The use of all available methods at both the basic and the clinical science levels will give a more complete and accurate understanding of the problems associated with the growth of bone(s). CONCLUSIONS: Many of us are concerned with the correction of malformations and deformations that can be a result of faulty growth of bones. Thus, further knowledge obtained in regard to the sites, direction, and amount of growth as well as pattern, rate, and mechanism will lead not only to a more accurate diagnosis of the bony defect but also to a better understanding of both prevention and treatment.

Animals↗
PubMed1991

Normal and abnormal growth at the nasoseptovomeral region.

The purpose of this report is to review and summarize a selected series of previously reported experiments at the nasoseptovomeral region dealing with both normal growth and the effects of certain operative procedures in young and adult rabbits. The methods of study included gross and serial cephalometric radiography with radiopaque implants, histology, and autoradiography. Findings indicated that the frontonasal suture region was an active secondary site of growth unaffected by extirpation. Examples of differential sutural growth were presented. The proximal and distal regions of both the nasal bone and septum were their most active sites of growth. Extirpations of the central section of the cartilaginous nasal septum resulted in severe upper facial deformity in young but not in adult rabbits. Trauma to the nasal bone region in the young rabbit did not result in severe facial deformity as did trauma to the cartilaginous nasal septum. Another purpose of this report is to present some of the different approaches used to study the nasoseptovomeral region.

Animals↗
PubMed1989

Carapace growth of the turtle Chrysemys scripta: a longitudinal study of shape using Fourier analysis.

Because the majority of morphological structures encountered in Biology are irregular in form, conventional metrics composed of distances, angles and ratios, are inefficient shape descriptors. To circumvent this drawback in the application of morphometrics to describe 2 dimensional shapes, an alternative procedure based on Fourier analysis was developed and applied to the turtle carapace. Once size differences were controlled for, the presence of shape changes with age could be demonstrated. This study showed that small systematic differences in the phase angle are associated with increase in carapace asymmetry. The differences were not visually apparent in the original data. These results reinforce the need for precise shape descriptors that are capable of measuring a large percentage of the informational content that is present in all biological forms.

Age Factors↗
PubMed1986

Growth pattern of the mandible: some reflections.

The dynamics of the growth of bones is a complex process. The growth pattern of the mandible has been assessed by the application of various methods described for the study of the growth of bones. Some of these lend themselves primarily to basic experimental rather than clinical work. The use of any one of these methods will reveal certain information. With the use of two or more of them in combination, however, considerably more accurate information can be obtained. Since John Hunter's classical descriptions more than 200 years ago, advances in the understanding of the growth pattern of the mandible have been possible with the refinement of older methods and the development of newer ones. To date, serial cephalometric roentgenography in concert with radiopaque implants, which serve as fixed reliable markers, is the most accurate method to determine the growth pattern of the mandible. To this armamentarium, digital subtraction radiography, computerized tomography, and magnetic resonance imaging may be methods that will offer more detailed and accurate information.

Animals↗
PubMed1986

Something of the nature of gross sutural growth.

A series of experiments was performed on monkeys, rabbits, and turtles to study gross sutural growth of bones. Radiopaque implants in conjunction with serial gross and radiographic measurements were employed. Differences in growth were observed between 5 facial sutures and also the same suture at different times. Growth was greatest at the zygomaticotemporal suture and least at the premaxillomaxillary suture. The nasal bone side of the frontonasal suture grew about twice as fact as the frontal bone side. In the turtle shell the midsagittal suture grew faster than a transverse suture. In all of the animals the rate of sutural growth decreased with increase in age. No gross regional growth disturbance was noted after resection of the frontonasal, midpalatine, or transpalatine sutures. After extirpation of the median palatine suture, it re-formed, in an eccentric position, in a number of instances. We concluded that bone growth that occurred at sutures was secondary or compensatory to some other factor.

Aging↗
PubMed1984

Differential growth and healing of bones and teeth.

A series of experiments was performed in turtles, rodents, lagomorphs, dogs, and monkeys to determine and correlate differential growth and healing of bones and teeth. Vital stains, radiopaque implants in conjunction with serial radiography, autoradiography, histology, and other methods were employed. Histologic differences and rate of endochondral (tibia, rib, base of skull, and mandibular condyle) and nasal cartilaginous septal growth were noted. Similarly, differences were observed in growth between five facial sutures and also for the same suture at different times. The nasal bone side of the frontonasal suture grew about twice as fast as the frontal bone side. In the turtle shell the midsagittal suture grew faster than a transverse suture. A variety of differences in rate of appositional (and resorptive) growth were noted at different sites of the mandible and nasal bone region. Generally, there was deposition of bone along the posterior border of the mandibular ramus and resorption of bone along the anterior border. Variations in the volume of the orbital contents influenced orbital growth. Bone was highly reactive, while enamel and dentin were nonreactive, to trauma.

Animals↗
PubMed1982

Eye and orbital size in the young and adult. Some postnatal experimental and clinical relationships.

The orbital volume in Dutch rabbits ranged from 3.6 ml at 98 days to 5.8 ml at 540 days of age. By 180 days of age the orbital volume had reached about its maximum of 5 ml and was 25% larger than at 100 days of age. The mean orbital volume was less at 540 than at 450 days of age. At 15 days of age the eye volume was about 20% of adult size, at 100 days of age about two thirds, at 180 days of age about 85% of adult size which was reached at about 300 days of age. The mean bulb volume was less at 540 than at 450 days of age. After evisceration, enucleation, or exenteration, in young rabbits there was a decelerated increase of orbital volume and a direct relationship between the lack of intraorbital mass and the subsequent lack of development of the orbit. The addition of a constant-sized implant in the young rabbit, after evisceration or enucleation of the eye, did not enhance orbital growth. In adult rabbits enucleation of the eye did not subsequently alter the orbital volume. In young rabbits an increase of the eye volume after multiple intrabulbar injections of silicone resulted in increase in orbital volume. The same procedure in adult rabbits increased neither the eye nor the orbital volume. Some clinical correlations are made.

Adolescent↗
PubMed1982

Growth pattern of the rabbit nasal bone region.

Two radiopaque implants were inserted into each left and right nasal bone in five female rabbits. Ventrodorsal cephalometric radiographs were taken 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. 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 about 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.

Animals↗
PubMed1981

Growth of the turtle Chrysemys scripta under constant controlled laboratory conditions.

The purpose of this study was to determine 1) growth of the turtle shell and change in weight under constant controlled laboratory conditions and 2) whether under these constant conditions there were seasonal changes. Fifty unfed refrigerated eight-week-old hatchling turtles Chrysemys scripta were received in October and maintained in aquaria with 16 hours of artificial light and eight hours of darkness, at 24-27 degrees C and a humidity of 30% and fed twice weekly. Gross linear measurements of the width and length of the plastron and carapace, and total body weights, were taken at eight weeks and thereafter at about six-week intervals. During the two-year period the mean increase of the plastron length was from 30.79 +/- 0.19 mm to 68.32 +/- 1.58 mm, plastron width from 24.23+/- 0.20 mm to 50.43 +/- 1.03 mm; carapace length from 32.47 +/- 0.24 mm to 75.21 +/- 1.82 mm, carapace width from 31.81 +/- 0.28 mm to 67.12 +/- 1.29 mm, and body weight from 6.94 +/- 0.15 gm to 80.63 +/- 5.02 gm. Calculated daily percent changes revealed that strongly correlated with its value at 786 days of age. No seasonal differences in growth were noted between the summer and winter periods when turtles would enter winter dormancy in certain natural environments. Environmental factors are reflected in the growth of the turtle.

Animals↗