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PubMedDate not supplied

Anomalies of craniofacial skeleton and teeth in cleidocranial dysplasia.

Mutations involving the transcription factor CBFA1 cause cleidocranial dysplasia (CCD) in man. Recently, a mouse model of CCD has been generated (Cbfal +/-) [Komori et al., 1997], and disturbances of osteoclast differentiation have been documented. It has been shown that these animals exhibit hypoplastic clavicles and nasal bones, and retarded ossification of parietal, interparietal, and supraoccipital bones. Humans with CCD show all these features, including severely retarded ossification of the cranial base, strongly suggesting that both intramembranous ossification and endochondral ossification are affected. In addition, CCD patients have multiple supernumerary teeth and delayed tooth eruption. The present report presents 3D reconstructions of computerised tomography (CT) scans of the craniofacial region of a CCD boy examined at both 1 and 7 years of age. The anomalies in craniofacial skeleton and teeth are analysed and compared to the findings of our previous clinical studies and to the findings in the animal model. Based on the available information, we suggest that osteoblast, osteoclast, and dentinoclast differentiation may be disturbed in CCD.

Child↗
PubMed1998

Common pediatric dental problems.

Physicians who provide primary care for children have a unique position to provide diagnostic, triage, educational, and preventive dental care for patients. Several papers have been published regarding primary pediatricians' participation in the preventive dental health care of their patients. One publication, a survey of physicians in Alabama focusing on physicians' overall awareness of dental issues, concluded that most physicians believe they have a role in the oral health of their patients, yet most were not aware of the American Academy of Pediatric Dentistry's recommendations. Most physicians report that they routinely perform oral examinations during physical examinations of children and deliver preventive, oral information by the age of 6 months or earlier; however, most recommend that infants' first visit should be at 3 years of age, not at the time of first-tooth eruption as the authors recommend. Furthermore, many primary care physicians do not talk about oral health during prenatal counseling. Many physicians understand the preventive advantages of fluoride, yet most do not prescribe vitamin combinations that contain fluoride. If an understanding of the aforementioned issues of dental care, as well as aspects of preventive care in infants and children, become more uniform among primary care physicians, the prevention-based practice of pediatric dentistry will become much more successful, and children and adults will enjoy better dental health.

Child, Preschool↗
PubMed1999

The effect of surgical technique on lingual nerve damage during lower 3rd molar removal by dental students.

We have previously shown that avoidance of lingual flap retraction with a Howarth periosteal elevator during lower 3rd molar removal, reduces the incidence of lingual nerve damage. In that study, the surgery was undertaken by qualified staff and we have now assessed the effect of revising the method taught to our junior undergraduate dental students. We evaluated the outcome of surgery undertaken by 2 consecutive years of students, each group being taught 1 of the 2 methods. A total of 200 patients requiring lower 3rd molar removal under local anaesthesia were included in the study. In year 1, the surgery included elevation of a lingual flap and insertion of a Howarth elevator adjacent to the lingual plate; in year 2 this part of the procedure was avoided by using a purely buccal approach. There were no significant differences between the levels of tooth eruption and types of impaction of the teeth removed in each year. Lingual sensory disturbance occurred in 3 patients in the 'flap' group (3.3%) and in 1 patient (0.9%) in the 'no flap' group. As this incidence is not significantly different in the 2 groups (P < 0.4), we conclude that avoidance of lingual retraction by students undertaking lower 3rd molar removal does not appear to place the lingual nerve at greater risk. In view of the results of our previous study, we therefore advocate this method for use in undergraduate dental education.

Clinical Competence↗
PubMed2002

A blind caries and fluorosis prevalence study of school-children in naturally fluoridated and nonfluoridated townships of Morayshire, Scotland.

OBJECTIVES: To undertake a blind caries and fluorosis prevalence study of Grade 1 (aged 5/6 yr) and Grade 4-7 (aged 8-12 yr) children from naturally water-fluoridated (1 ppm, since 1985) Burghead, Findhorn & Kinloss (F), and nearby nonfluoridated Buckie & Portessie (N-F), in rural Morayshire, Scotland. METHODS: A blind clinical (+ 10% repeats) caries study of the above townships' 5/6-yr-old lifetime (15 F; 43 N-F), and 8-12-yr-old lifetime (55 F; 136 N-F)/school-lifetime (31 F; 37 N-F) residents was undertaken following bussing of these children to a common examination site in close-by Elgin Town Hall. Initially, each child was asked about their own perception of the aesthetics of their maxillary front teeth. Fluorosis was assessed clinically using the TF Index, as well as photographically - for later blind scoring (+ 10% repeats for lifetime 8-12-yr-olds) of slides by four dental and two lay 'jurors', alongside a now-established UK 'bench-mark' mildly mottled (TFI = 2), fluorosis comparator slide, judged in previous studies to be aesthetically lay-acceptable. In addition, by parental questionnaire, information was sought concerning their child's fluoride supplement and dentifrice usage histories. RESULTS: For 5/6-yr-olds, mean primary caries scores were 96.0% less in fluoridated than nonfluoridated subjects (P < 0.01). In 8-12-yr-olds, DMFT values favoured water-fluoridated subjects; their caries-free trend was significant (P < 0.001 overall). Clinically, 33% of all lifetime F subjects and 18% of all N-F pupils had fluorosed maxillary anterior teeth (P = 0.045), but no statistically significant difference was found between the 7% F and 3% N-F subjects with TFI scores > 2 (P = 0.25). Photographically, 'jury' mottling assessment (+ 10% repeats) of projected slides resulted in at least 1 : 6 positive scores in 43.6% of F and 30.9% of N-F pupils, albeit they unanimously scored only nine F and five N-F children as having fluorosed teeth (P < 0.01). In no case did all members score TFI > 2. Dental and lay scorers rated TFI = (1/2) in only a further 9.1% and 5.5% of F subjects, respectively, compared to 0.7% and 1.5% respectively of N-F pupils. Again, TFI > 2 was scored unanimously in no child. No differences were found regarding the children's own degree of anterior tooth aesthetic nonacceptability between F (11%) and N-F (12%) prevalence (P = 0.75). Finally, only one F child had taken F supplements and, while 26 N-F had used F drops, no significant relationship was found between their usage and TFI values in the latter group (P = 0.49). Additionally, no relationship was noted between clinical TFI scores and the age at which parents stated fluoridated dentifrice toothbrushing commenced, between 0 and 24 + months of age. CONCLUSIONS: Considerable caries benefit has accrued to those Morayshire rural children who have received naturally fluoridated water (at 1 ppm) throughout their lives, as compared to their socioeconomically similar, nonfluoridated rural counterparts. Furthermore, in spite of all but two subjects claiming to have brushed regularly with fluoridated dentifrice (and no evidence of the availability of nonfluoridated toothpaste being purchasable in the five townships), only borderline mild fluorosis disadvantages have been noted clinically, and none by the subjects' own aesthetic perceptions. Finally, no evidence was found to suggest any delay in permanent tooth eruption patterns of the F subjects. It would seem appropriate therefore, that adjustment of Scots' drinking waters' natural fluoride levels to 1 ppm should be pursued to extend similar dental advantages to the vast majority of that population (both young and old) which, it is well documented, has the worst dental health of mainland UK.

Age Factors↗
PubMed2003

Rates of anterior tooth wear in Middle Pleistocene hominins from Sima de los Huesos (Sierra de Atapuerca, Spain).

This study presents quantitative data on the rates of anterior tooth wear in a Pleistocene human population. The data were obtained for the hominin sample of the Sima de los Huesos site in Atapuerca, Spain. The fossil record belongs to a minimum of 28 individuals of the same biological population, assigned to the species Homo heidelbergensis. We have estimated the original and the preserved crown height of the mandibular incisors (I1 and I2) of 11 individuals, whose age at death can be ascertained from the mineralization stage and tooth eruption. Results provide a range of 0.276-0.348 and 0.288-0.360 mm per year for the mean wear rate of the mandibular I1 and I2, respectively, in individuals approximately 16-18 years old. These data suggest that incisors' crowns would be totally worn out toward the fifth decade of life. Thus, we expect the life expectancy of this population to be seriously limited. These data, which could be contrasted with results obtained on hominins at other sites, could be of interest for estimating the death age of adult individuals.

Adolescent↗
PubMed1996

Adjustment of the M-component of the DMFS index for prevalence studies of older adults.

Cross-sectional studies of caries in older adults report a substantial number of missing teeth, making it difficult to estimate caries experience accurately. The goal of this study was to improve the method of estimating caries experience as expressed by the DMFS index in population groups with missing teeth. The adjustment was demonstrated with reference to the Piedmont 65+ Dental Study conducted on a random sample of 363 community-dwelling older adults in North Carolina who were followed for 5 years. These older dentate adults had a mean (+/-SE) of 11.7 +/- 0.5 teeth missing at baseline, 56.1 +/- 2.5 missing surfaces and a DMFS of 86.7 +/- 2.0. A predicted caries prevalence was determined from the DFS at 5 yrs plus the 5-yr DFS incidence and the baseline DFS of teeth lost during the study period. Then a formula was developed that would estimate the predicted caries prevalence as a function of the observed 5-yr DMFS. This formula provided a good estimation of caries prevalence at 5 yrs (DMFSadj) when compared with the predicted prevalence (paired t-test, p > 0.05), while prevalence was underestimated by the DFS and greatly overestimated by the traditional DMFS index. Subgroup analyses by race, sex, and periodontal status also indicated that the DMFSadj resulted in patterns of estimates similar to the predicted prevalence, while the DFS and the DMFS were likely to result in different findings. The DMFS from the time of tooth eruption also was adjusted using this formula. The resulting analyses of subgroup differences in caries were not different from the previous estimates based on the 5-yr historical data, indicating that the adjustment of all M surfaces avoids the biases inherent in the traditional DMFS and DFS indices. This study showed that predicted caries prevalence could be estimated by adjusting the M component of the DMFS. It appears that this adjustment formula can be used without obvious bias, but additional studies are needed to provide adjustment figures for populations with different caries prevalences.

Black or African American↗
PubMed2001

Incremental lines of dental cementum in biological age estimation.

The aim of this study is to evaluate the use of counting incremental lines of dental root cementum for biological age determination, and to compare it with alternative methods. Two samples were taken: 51 teeth from 49 individuals of known age obtained at the Stomatological Clinic, Vilnius University, as well as the canine teeth from the remains of 48 individuals from the mass graves of Tuskulenai in Vilnius (inhumed 1944-47). In the latter sample, the chronological age of 43 individuals was known through personal identification. Undecalcified teeth were sectioned with the Leica SP 1600 microtome diamond saw, and incremental line count as a blind test was made on sections of 35 to 100 microns thickness. Incremental line count was possible in 82-86 percent of cases. The results of three independent counts showed that intra-observer bias has no significant impact. Biological age was estimated by adding incremental line number to the average age of tooth eruption. It was found that mean absolute error was 6.46 years for the 1st sample, 6.27 years for the 2nd sample, and in some cases exceeded 10 years. For the 2nd sample, the results were compared to those of other methods such as endocranial suture ossification, pubic symphysis morphology and the "combined" method of Nemeskéri. All four methods yield a similar correlation in regard to an individual's chronological age. The highest correlation was found for the combined method, and the lowest one for public symphysis morphology. All correlations had a similar standard error. Thus our assessment is less enthusiastic than in some past studies; it is suggested that the incremental lines rather have a similar use as other methods.

Adolescent↗
PubMedDate not supplied

Early and transient osteopetrosis in microphthalmic MIB-rats.

Microphtalmic blanc mutation (mib/mib) displays a very mild form of osteopetrosis in rats. The autosomal recessive mib mutation shows pleiotropic expressions in homozygotes. Microphtalmia, absence of eye and skin pigmentation, retardation in the tooth eruption were observed in the mutants. Most bone abnormalities occurred in newborns. An increased radiological opacity of long bones, persistence of primitive bone in medullary cavities, reduced number of poorly differentiated osteoclasts in mandibulae, reduced number of mononuclear peritoneal cells as well as reduced number of mononuclear osteoclast precursors in peritoneal cell population were found. In 3 weeks old and in adult mutants, both bone structure and the number of mandible osteoclasts appear normal, but the number of blood monocytes, peritoneal cells and mononuclear osteoclast precursors in peritoneal cell population remain significantly lower than in the healthy littermates. These observations indicate that the early failure of osteoclast differentiation and maturation is transient in the mib/mib form of osteopetrosis.

Abnormalities, Multiple↗
PubMed1992

Culture and characterization of dental follicle cells from rat molars.

Because the dental follicle is necessary for the eruption of teeth of limited eruption, it was the objective of this study to determine if the cells of the follicle could be cultured in vitro. To achieve this, dental follicles and associated enamel organs were dissected from the first and second mandibular molars of 6-7-day-old rats (secretory stage of amelogenesis), and then cultured in a medium that promotes fibroblast growth--the predominant cell type of the dental follicle. The cultured cells grew to confluency and were kept through 3 passages before experimentation. The cultured cells were fibroblastic in shape, elongate with processes, and transmission electron microscopy revealed that they contained an abundant rough endoplasmic reticulum, but did not form desmosomes. Immunofluorescent staining for anti-vimentin showed that all the cells stained and electron-microscopic immunogold labeling indicated that the antibody was associated with intermediate filaments. As revealed by SDS-polyacrylamide gel electrophoresis and Western blotting, the cultured cells synthesized and secreted the extracellular matrix molecules fibronectin and procollagens. Subsequent immunofluorescence staining of permeabilized and non-permeabilized cells confirmed the presence of fibronectin and type I collagen both intra- and extracellularly. Thus, based on all the above characteristics, the cultured cells appeared to be fibroblasts derived from the dental follicle, although a few of the fibroblasts may be derived from undifferentiated mesenchymal cells interposed between the alveolar bone and follicle. Experiments now can be conducted to determine how these cultured cells respond directly to growth factors that alter the rates of tooth eruption.

Animals↗
PubMedDate not supplied

Morphology of the mandibular condyle in "toothless" osteopetrotic (op/op) mice.

The defective bone resorption in the osteopetrotic op/op mouse brings about cranio-facial deformation and failure of tooth eruption. This study was conducted to elucidate the morphological changes of the condylar head and mandibular ramus in growing op/op mice. In normal mice, the condylar head is much broader than the ramus beneath it, enlargement and ossification of the condylar head begin after weaning, and the ramus becomes compact bone tissue. None of these changes were found in the op/op mice in the present observation. The condylar head was small, and its inner side was occupied by hypertrophic cartilage cells. In spite of the lack of bone resorption in op/op mice, the compaction of the mandibular ramus, which was composed of bone trabeculae, occurred later than that in normal mice. In view of recently studies reported evidence that local mechanical stress regulates the bone formation, we consider that undergrowth of the condylar head and the ramus in the op/op mouse results from not only a deficiency of osteoclasts but also insufficient mechanical stress from mastication.

Animals↗
PubMed2001

Amelogenin-deficient mice display an amelogenesis imperfecta phenotype.

Dental enamel is the hardest tissue in the body and cannot be replaced or repaired, because the enamel secreting cells are lost at tooth eruption. X-linked amelogenesis imperfecta (MIM 301200), a phenotypically diverse hereditary disorder affecting enamel development, is caused by deletions or point mutations in the human X-chromosomal amelogenin gene. Although the precise functions of the amelogenin proteins in enamel formation are not well defined, these proteins constitute 90% of the enamel organic matrix. We have disrupted the amelogenin locus to generate amelogenin null mice, which display distinctly abnormal teeth as early as 2 weeks of age with chalky-white discoloration. Microradiography revealed broken tips of incisors and molars and scanning electron microscopy analysis indicated disorganized hypoplastic enamel. The amelogenin null phenotype reveals that the amelogenins are apparently not required for initiation of mineral crystal formation but rather for the organization of crystal pattern and regulation of enamel thickness. These null mice will be useful for understanding the functions of amelogenin proteins during enamel formation and for developing therapeutic approaches for treating this developmental defect that affects the enamel.

Amelogenesis Imperfecta↗
PubMed1990

[Tooth formation and eruption in skeletal Class II and Class III malocclusions].

The purpose of this study was to investigate the timing of the formation and eruption of the permanent teeth between Skeletal Class II and Class III malocclusions right before pubertal growth period. Samples consisted of twenty five Japanese girls of Class II and Class III malocclusions, respectively, with Class I girls as a control. Materials used in this study were panoramic X-rays, dental X-rays and intraoral photographs of each sample, all taken at age of 8 years. Lateral cephalometric X-rays, wrist bone X-rays and records of standing height were used to study the craniofacial characteristics and the stage of bone maturation. Results were as follows: 1. Lower teeth formation of Class III group tended to be advanced when compared with Class II group, especially at molars. 2. There was no significant difference between the two groups with regard to the timing of eruption except lower lateral incisors, but eruption of the upper second molar of Class III group tended to be delayed. Results suggested that the skeletal disharmony may be associated with different timing of formation and eruption of the permanent teeth.

Child↗
PubMed2000

Oral health and hospitalization in Western Australian children.

Over the past 20 years, the prevalence of dental disease in Western Australian children has diminished. The causes of this significant improvement in health are associated with better care models, water fluoridation and changes in lifestyle. In this study, the authors examine the reasons for hospitalization for oral health conditions in Western Australia for the calendar year 1995 using the Health Department of WA database. A total of 3,754 episodes of care (4,395 bed days) was recorded for dental conditions. Dental caries resulted in the fifth and sixth highest number of episodes of hospitalization in preschool (1-4 years) and primary-school age (5-12 years) children respectively. Abnormal tooth eruption resulted in the highest number of episodes of hospitalization in high-school age (13-17 years) children. From the age-stratified rates of hospitalization (per 1000), non-Aboriginal children were more than twice as likely to enter hospital for dental related conditions. The primary cause of this is the 15 times higher rate of hospitalization for high-school age non-Aboriginal children which clearly reflects the greater use of services for impacted third molars by the metropolitan non-Aboriginal community. Examination of the distribution by health service region revealed the hospitalization rate was significantly less than the state average for the Kimberley, Pilbara, Northern Goldfields and Wanneroo regions. These data reflect the paucity of oral health care available to residents of these regions, particularly the northwest, and does not reflect a diminished burden of disease. Similarly, the rate of hospitalization for Aboriginal children reflects population and service delivery differences particularly in regional and remote WA. These data highlight the need to develop new strategies in oral health care to target 'at risk' groups in the community, particularly new parents of young children. The preventive measures associated with good oral health in children are clearly aligned with those for good general health and can be integrated into existing health messages.

Adolescent↗
PubMed2002

The osteopetrotic mutation toothless (tl) is a loss-of-function frameshift mutation in the rat Csf1 gene: Evidence of a crucial role for CSF-1 in osteoclastogenesis and endochondral ossification.

The toothless (tl) mutation in the rat is a naturally occurring, autosomal recessive mutation resulting in a profound deficiency of bone-resorbing osteoclasts and peritoneal macrophages. The failure to resorb bone produces severe, unrelenting osteopetrosis, with a highly sclerotic skeleton, lack of marrow spaces, failure of tooth eruption, and other pathologies. Injections of CSF-1 improve some, but not all, of these. In this report we have used polymorphism mapping, sequencing, and expression studies to identify the genetic lesion in the tl rat. We found a 10-base insertion near the beginning of the open reading of the Csf1 gene that yields a truncated, nonfunctional protein and an early stop codon, thus rendering the tl rat CSF-1(null). All mutants were homozygous for the mutation and all carriers were heterozygous. No CSF-1 transcripts were identified in rat mRNA that would avoid the mutation via alternative splicing. The biology and actions of CSF-1 have been elucidated by many studies that use another naturally occurring mutation, the op mouse, in which a single base insertion also disrupts the reading frame. The op mouse has milder osteoclastopenia and osteopetrosis than the tl rat and recovers spontaneously over the first few months of life. Thus, the tl rat provides a second model in which the functions of CSF-1 can be studied. Understanding the similarities and differences in the phenotypes of these two models will be important to advancing our knowledge of the many actions of CSF-1.

Alternative Splicing↗
PubMed1999

Cytokine secretion of periodontal ligament fibroblasts derived from human deciduous teeth: effect of mechanical stress on the secretion of transforming growth factor-beta 1 and macrophage colony stimulating factor.

The periodontal ligament may play an important role in tooth eruption, root development and resorption. The tissue physiologically receives mechanical force during mastication. We focused on the effects of intermittent mechanical strain on the cytokine synthesis of periodontal ligament (PDL) fibroblasts in vitro. The cells were derived from human periodontal ligament of deciduous teeth (HPLF-Y) and permanent teeth (HPLF). The two kinds of PDL cells and human gingival fibroblasts (HGF) were cultured in flexible bottomed culture plates. The cells were mechanically stretched at 5% elongation, 3-cycles/min for 24 h on d 7 in culture using a Flexercell strain unit. After the stretching, we measured DNA content and alkaline phosphatase activity in the cell layer, transforming growth factor beta 1 (TGF-beta 1) and macrophage colony stimulating factor (M-CSF) contents in the conditioned medium. The TGF-beta 1 level in the conditioned medium of HPLF was significantly higher than that of HPLF-Y and HGF. It was stimulated by mechanical stretching only on HPLF, whereas no significant effect was observed on HPLF-Y and HGF. M-CSF secretion was inhibited by the stretching on all of HPLF, HPLF-Y and HGF. 1 alpha, 25 dihydroxy vitamin D3 (D3) stimulated M-CSF secretion into the culture medium of both HPLF and HPLF-Y, but the stretching inhibited M-CSF secretion and completely blocked the enhancement by D3. These data suggest that periodontal ligament cells synthesize and secrete the molecules as autocrine or paracrine factors that affect bone remodelling and root resorption and the level of those factors change in response to mechanical stress.

Alkaline Phosphatase↗
PubMed1998

Ultrastructural features of odontoclasts that resorb enamel in human deciduous teeth prior to shedding.

Three dental hard tissues, i.e., cementum, dentin, and enamel, are resorbed by multinucleated cells referred to as "odontoclasts." These cells have morphological and functional characteristics similar to those of bone-resorbing osteoclasts. However, concerning enamel resorption, which is a process that may occur during tooth eruption, satisfactory ultrastructural data on odontoclastic resorption are still lacking. Ultrastructural and histochemical characteristics of odontoclasts resorbing enamel of human deciduous teeth prior to shedding were examined by means of light microscopy and transmission and scanning electron microscopy. Odontoclasts that that resorbed enamel were tartrate-resistant acid phosphatase (TRAP)-positive multinucleated giant cells that were essentially the same as those that resorbed dentin and cementum. Ultrastructurally, they had numerous mitochondria, lysosomes, and free polysomes in their cytoplasm. In addition, they were characteristically rich in large cytoplasmic vacuoles containing enamel crystals in the cytoplasm opposite the ruffled border. Although they extended a well-developed, ruffled border against enamel surface, a clear zone--an area typically devoid of organelles--was rarely seen in these cells. In many cases, the cells were in very close contact with the enamel surface by the peripheral part of their cytoplasm. The enamel prisms at the resorption surface contained more loosely packed and electron-lucent enamel crystals compared with those of unresorbed, intact enamel. Furthermore, numerous thin needle- or plate-like enamel crystals that were liberated from the enamel matrix were found in the extracellular channels of the ruffled border and in various-sized cytoplasmic vacuoles in their cytoplasm. The superficial layer of the enamel matrix undergoing odontoclastic resorption stained positively with toluidine blue and for TRAP activity. The results of the present study suggest that odontoclasts resorbing enamel secrete acids as well as organic components, including hydrolytic enzymes, into the resorption zone underlying their ruffled border and that they phagocytose crystals that have been liberated from the partially demineralized enamel matrix by acids, subsequently dissolving them intracellularly.

Acid Phosphatase↗
PubMed1996

Osteoglophonic dysplasia: review and further delineation of the syndrome.

We report on a boy with clinical and radiologic findings of osteoglophonic dysplasia. He had craniostenosis, "bizarre," expansile cystic lesions in the diaphyses, delayed tooth eruption, and progressive rib expansion typical of the syndrome. Initially delayed psychomotor development with later normal intelligence, early feeding and breathing difficulty, and speech delay are also characteristic of the disorder. Manifestations, not previously reported in osteoglophonic dysplasia, present in the propositus are spontaneous fractures resulting in pseudoarthroses through cystic and dysplastic foci in his proximal femoral shafts and right humerus, pretibial dimples, hypospadias, marked rib expansion, and absence of significant vertebral abnormality. These findings expand the spectrum of osteoglophonic dysplasia.

Bone Diseases, Developmental↗
PubMed2000

Neural and behavioral teratological evaluation of rats exposed to ultra-wideband electromagnetic fields.

Several investigators have reported teratologic effects of electromagnetic field exposure. The majority of these studies have been performed at levels of exposure that could produce substantial heating of the animals. New and unique sources of ultra-wideband (UWB) electromagnetic fields are currently being developed and tested that are capable of generating nonthermalizing, high-peak-power, microwave (MW) pulses with nanosecond (ns) pulse widths, picosecond (ps) rise times, and an UWB of frequencies. Our study was performed to determine if teratological changes occur in rat pups as a result of (i) daily UWB exposures during gestation days 3-18, or (ii) as a result of both prenatal and postnatal (10 days) exposures. Dams were exposed either to (i) UWB irradiation from a Kentech system that emitted a 55 kV/m-peak E field, 300 ps rise time, and a 1.8 ns pulse width, average whole-body specific absorption rate 45 mW/kg; (ii) sham irradiation; or (iii) a positive control, lead (Pb) acetate solution (2000 microg/ml) continuously available in the drinking water. Offspring were examined for ontogeny (litter size, sex-ratios, weights, coat appearance, tooth-eruption, eye-opening, air-righting, and ultrasonic stress vocalizations). Male pups were tested on various performance measures (locomotor, water-maze learning, and fertilization capabilities). The pups postnatally exposed were examined for hippocampal morphology and operant behavior. Behavioral, functional, and morphological effects of UWB exposure were unremarkable with these exceptions: (i) The UWB-exposed pups emitted significantly more stress vocalizations than the sham-exposed pups; (ii) the medial-to-lateral length of the hippocampus was significantly longer in the UWB-exposed pups than in the sham-exposed animals; (iii) male offspring exposed in utero to UWB mated significantly less frequently than sham-exposed males, but when they did mate there was no difference in fertilization and offspring numbers from the sham group. There does not appear to be a unifying physiological or behavioral relationship among the significant differences observed, and our findings could be due to the expected spurious results derived when a large number of statistical comparisons are made. Significant effects found between our positive-controls and other groups on numerous measures indicates that the techniques used were sensitive enough to detect teratological effects. Bioelectromagnetics 21:524-537, 2000. Published 2000 Wiley-Liss, Inc.

Animals↗