The effect of growth hormone on craniofacial growth and dental maturation in Turner syndrome.

Serial cephalometric and panoramic radiographs from a mixed longitudinal group of 28 subjects with Turner syndrome (TS), age 4.4-19.0 years, were evaluated for annualized growth increments of the craniofacial complex and dental development and were compared with a longitudinal control group from the Burlington growth study. The short and retrognathic face characteristic of the syndrome was due largely to the increased cranial base angle, decreased posterior face height, and decreased mandibular length, all of which were significantly different from the controls. Although increases in statural height occurred in the TS children who were treated with human growth hormone (GH), there was little or no effect on growth of the jaws, particularly in the older subjects, and the characteristic facies of the syndrome persisted. Dental development was advanced in all TS subjects, and GH administration had no effect on the rate of dental development.

Growth hormone and craniofacial changes: preliminary data from studies in Turner's syndrome.

Normal craniofacial and dental growth and development is dependent on growth hormone (GH) and insulin-like growth factor I (IGF-I). Deficiencies of either during childhood cause diminished growth of the maxilla and (to a greater degree) the mandible. Dental development/eruption also is compromised. Conversely, excessive GH/insulin-like growth factor I causes overgrowth, with the mandible again more affected than the maxilla. Replacement therapy in deficiency conditions generally normalizes craniofacial growth. Systemic GH also has been used in other disorders for which overt deficiency of GH has not been demonstrated. One such condition, Turner's syndrome, is now widely treated with GH. Although systemic GH in Turner's syndrome has been shown to positively affect stature, the effects on craniofacial growth and dental development/eruption are largely unknown. To explore these issues, standardized lateral radiographs of seven untreated patients with Turner's syndrome were analyzed and revealed hypoplasias of the cranial base, maxilla, and mandible. Dental development/eruption of patients with Turner's syndrome was found to be significantly advanced (by 0.63 years), relative to control subjects, in a separate study. Annual radiocephalometric measurements of 19 patients with Turner's syndrome treated with GH were compared with nonaffected control subjects over 1 year of treatment. Compared with age-matched historic control subjects, all maxillary-and most mandibular-growth measures were within 2 standard deviations of control. However, in our patients with Turner's syndrome, we found two measures of mandibular growth that deviated by more than 3 standard deviations from control. These data, although preliminary and only encompassing a short period, indicate that mandibular growth may be more affected than is maxillary growth by GH treatment and should be monitored over long-term-therapy.

6-Hydroxydopamine treatment of neonatal rats. I. Effects on the development of the spinal cord noradrenergic system.

The spinal cord contains noradrenergic (NA) pathways which descend from cell bodies in the medulla oblongata and pons to terminate at all levels in the spinal gray matter. The present studies sought to determine the patterns of postnatal development of pre- and postsynaptic elements of NA transmission in the spinal cord. Significant presynaptic development is evident at birth as reflected by substantial high-affinity uptake of norepinephrine (NE) into synaptosomes (0.65-0.90 pmol/mg protein). There is a subsequent increase in uptake on postnatal day (PND) 5, followed by a decrease in 5-10 days to essentially adult levels, starting on PND 20 (0.30-0.35 pmol/mg protein). This decrease in NE uptake occurs coincident with increases in the density of postsynaptic alpha 1 and beta adrenergic receptors and also NE-stimulated accumulation of 3',5'-cyclic adenosine monophosphate (cAMP). Peaks in the development of alpha 1 receptors (PND 10) and beta receptors (PND 20) and NE-stimulated cAMP accumulation (PND 15) were also followed by decreases to adult levels. The neurotoxin 6-hydroxydopamine (6-OHDA) was administered at birth to determine the effects of denervation on the development of the spinal NA systems. At each day following 6-OHDA, synaptosomal uptake of [3H]NE was reduced by two-thirds compared with control values. alpha 1 and beta adrenergic receptor binding are uniformly increased along with a parallel increase in NE-stimulated accumulation of cAMP. While uniformly increased over control, the pattern of postnatal increases and decreases in receptors and cAMP accumulation is maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Hydroxydopamine treatment of neonatal rats. II. Effects on the development of the hindlimb flexor reflex.

The flexor reflex (FR) of the hindlimb was measured in rats at various ages between postnatal days (PND) 12-45, in vehicle-treated control rats and in rats treated with 6-hydroxydopamine (6-OHDA) (100 mg/kg, i.p.) on the first and second days after birth. The hindlimb FR was elicited by graded electrical stimulation of the footpad (0.1-2.0 mA) and quantified by the amplitude of the flexion in grams. The half maximal FR response was evoked by 1.2 mA and was 2-3 g in animals at PND 12-17 and 9-10 g in animals on PND 30 and 45. A similar age dependency was evident in the maximum hindlimb FR evoked by 2.0 mA; the maximum FR was 4.7 +/- 0.5 g on PND 12 and 24 +/- 2 g on PND 45. In rats treated with 6-OHDA, the strength of the FR was similar to that of the controls up to PND 15. However, the FR was increased 25% by PND 17 and 200% by PND 45 in the 6-OHDA-treated animals, versus controls. Pretreatment with clonidine (100 micrograms/kg, i.p.), which activates alpha 1 receptors under the current experimental conditions, did not enhance the FR in control animals. However clonidine pretreatment caused an increase of 400-800% in the FR in the 6-OHDA-treated animals at PND 15 and beyond. Our companion paper demonstrated that as early as PND 5, there was a significant increase (P < 0.05) in alpha 1 receptors in the spinal cord of 6-OHDA-treated animals, versus the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Control of orthodontic pain.

Orthodontics is an elective dental procedure generally believed to involve pain. In certain individuals, the pain caused by orthodontic tooth movement can be a major negative component of the entire therapy. Clinicians who are aware of this fact can attempt to prevent pain rather than ameliorate it once it is present and help make the experience a more positive one for the patient. Orthodontic forces should be kept at suitable levels and care taken to prevent trauma due to hyperocclusion. In procedures suspected to cause significant painful stimuli (such as forcing bands on unseparated teeth, removal of fixed expanders, initial placement of archwires, or lingual arches), or in particularly sensitive patients, the use of analgesics may be indicated. These agents should be taken prior to the procedure and for a minimum of 24 hours following the procedure. Acetaminophen is recommended in young children, while nonsteroidal anti-inflammatory agents are indicated in older patients.

Surgical-orthodontic correction of mandibular deficiency: five-year follow-up.

Changes in dental and skeletal relationships at 5 years postsurgery were evaluated in a group of 35 patients whose mandibular deficiency had been corrected by the same surgeon, using sagittal split osteotomy of the mandibular ramus. From 1 to 5 years postsurgery, there was a small (0.9-mm) but statistically significant mean decrease in mandibular length (condylion to point B). In six patients, the decrease in mandibular length was 2 to 4 mm, and in two it was more than 4 mm, but only one of these individuals had more than a 2-mm increase in overjet. There was no mean change in overjet, but three patients had a 2 to 4-mm increase. Of these, one had 3.2 mm shortening of the mandible, one had 1.4 mm shortening of the mandible, and one had no change in mandibular length but repositioning of the incisors. Most patients had a deep overbite initially, and there was a tendency for the bite to deepen between the first and fifth years postoperatively, more as a result of extrusion of incisors than of mandibular rotation. Remodeling of the gonial angle area, with vertical and/or horizontal repositioning of gonion, was noted in more than half the subjects. It appears that morphologic changes related to continued skeletal remodeling, often compensated for by small changes in mandibular posture or tooth positions, continue after 1 year postsurgery for many patients.

Bone physiology and metabolism in dental implantology: risk factors for osteoporosis and other metabolic bone diseases.

Placing a dental implant elicits a time-dependent bone response controlled by wound-healing factors (cytokines, bioelectrical signals), biomechanics (gravitational, functional, and therapeutic loads), and mineral metabolism (hormones, diet, excretion). The osseous response to an implant involves four physiological stages: (1) endosteal and periosteal callus formation; (2) compaction and remodeling of the callus; (3) remodeling (turnover) of the nonvital interface and adjacent bone; and (4) maturation (secondary mineralization) of new bone. Long-term maintenance of a rigid implant interface is related to continual bone remodeling. Common metabolic bone disorders affecting potential implant patients are osteopenia ("osteoporosis"), renal osteodystrophy, osteomalacia, and Paget's disease. The most prevalent problem is a long-term negative calcium balance leading to a compromise in bone strength. Symptomatic osteoporosis (usually wrist, hip, and/or spine fractures) affects 4 to 50 percent of the population depending on age, race, sex, endocrine status, and life-style. Postmenopausal white and Asian females present the greatest risk. The jaws of "osteoporotic" adults are variably affected because of the moderating influence of mechanical function. Management of metabolic bone disorders is an important consideration in diagnosis, treatment planning, and long-term monitoring of dental implants. Bone metabolic counseling, a natural extension of preventative dentistry, is an unexpected benefit readily appreciated by patients and their families.

Galileo ultraviolet spectrometer experiment: initial venus and interplanetary cruise results.

The Galileo Extreme Ultraviolet Spectrometer obtained a spectrum of Venus atmospheric emissions in the 55.0- to 125.0-nanometer (nm) wavelength region. Emissions of helium (58.4 nm), ionized atomic oxygen (83.4 nm), and atomic hydrogen (121.6 nm), as well as a blended spectral feature of atomic hydrogen (Lyman-beta) and atomic oxygen (102.5 nm), were observed at 3.5-nm resolution. During the Galileo spacecraft cruise from Venus to Earth, Lyman-alpha emission from solar system atomic hydrogen (121.6 nm) was measured. The dominant source of the Lyman-alpha emission is atomic hydrogen from the interstellar medium. A model of Galileo observations at solar maximum indicates a decrease in the solar Lyman-alpha flux near the solar poles. A strong day-to-day variation also occurs with the 27-day periodicity of the rotation of the sun.

Photometry from voyager 2: initial results from the neptunian atmosphere, satellites, and rings.

The Voyager photopolarimeter successfully accomplished its objectives for the Neptune encounter, performing measurements on the planet, several of its satellites, and its ring system. A photometric map of Neptune at 0.26 micrometer (microm) shows the planet to be bland, with no obvious contrast features. No polar haze was observed. At 0.75 microm, contrast features are observed, with the Great Dark Spot appearing as a low-albedo region and the bright companion as being substantially brighter than its surroundings, implying it to be at a higher altitude than the Great Dark Spot. Triton's linear phase coefficients of 0.011 magnitudes per degree at 0.26 microm and 0.013 magnitudes per degree at 0.75 microm are consistent with a solid-surface object possessing high reflectivity. Preliminary geometric albedos for Triton, Nereid, and 1989N2 were obtained at 0.26 and 0.75 microm. Triton's rotational phase curve shows evidence of two major compositional units on its surface. A single stellar occultation of the Neptune ring system elucidated an internal structure in 1989N1R, in the approximately 50-kilometer region of modest optical depth. 1989N2R may have been detected. The deficiency of material in the Neptune ring system, when compared to Uranus', may imply the lack of a "recent" moon-shattering event.

Photometry from voyager 2: initial results from the uranian atmosphere, satellites, and rings.

The Voyager 2 photopolarimeter successfully completed the Uranus encounter, acquiring new data on the planet's atmosphere, its principal satellites, and its ring system. Spatially resolved photometry of the atmosphere at 0.27 micrometer shows no enhancement in absorption toward the pole, unlike the case for Jupiter and Saturn. Stellar occultation measurements indicate the temperature at the 1-millibar level over the north pole is near 90 kelvins. The geometric albedos of the five large satellites of Uranus were measured at 0.27 and 0.75 micrometer and indicate the presence of low albedo, spetrally flat absorbing material. Titania seems to have a fluffy surface, as indicated by its phase curve. The nine ground-based rings were detected, and their internal structure, optical depths, and positions were determined. The sharp edges of the in ring made it possible to measure its edge thickness (less than 150 meters) and particle sizes (less than 30 meters); little or no dust was detcted. New narrow rings and partial rings (arcs) were measured, and the narrow component of the eta ring was found to be discontinuous.

An intraventricular infusion model for inducing morphine dependence in rats: quantitative assessment of precipitated withdrawal.

An experimental model of morphine dependence, in which rats were made dependent upon morphine by intraventricular infusion, is described. Morphine dependence was assessed and quantified by a series of withdrawal signs that were induced by the intraperitoneal administration of the morphine antagonist naloxone. The infusion of different concentrations of morphine resulted in the production of physical dependence, the severity of which was directly correlated with the concentration of morphine infused. A weak to moderate degree of dependence characterized by such withdrawal signs as teeth chattering, whole-body shakes, and vocalization was produced by infusions of morphine less than 5 micrograms/hr. A strong degree of physical dependence characterized by additional dominant withdrawal signs such as jumping and launching was produced by the infusion of 50 micrograms/hr morphine. The morphine pellet model that most closely approximated this degree of dependence was a three-pellet model in which a single 75-mg morphine pellet was implanted at 48-hr intervals. Abstinence precipitated by removal of the morphine-containing osmotic minipumps was characterized primarily by teeth chattering and whole-body shakes which persisted for at least 48 hr.

Photopolarimetry from voyager 2; preliminary results on saturn, titan, and the rings.

The Voyager 2 photopolarimeter was reprogrammed prior to the August 1981 Saturn encounter to perform orthogonal-polarization, two-color measurements on Saturn, Titan, and the rings. Saturn's atmosphere has ultraviolet limb brightening in the mid-latitudes and pronounced polar darkening north of 65 degrees N. Titan's opaque atmosphere shows strong positive polarization at all phase angles (2.7 degrees to 154 degrees ), and no single-size spherical particle model appears to fit the data. A single radial stellar occultation of the darkened, shadowed rings indicated a ring thickness of less than 200 meters at several locations and clear evidence for density waves caused by satellite resonances. Multiple, very narrow strands of material were found in the Encke division and within the brightest single strand of the F ring.

Photometric observations of jupiter at 2400 angstroms.

The photopolarimeter instrument on Voyager 2 was used to obtain a map of Jupiter at an effective wavelength of 2400 angstroms. Analysis of a typical north-south swath used to make this map shows strong absorption at high latitudes by a molecular or particulate constituent in the Jovian atmosphere. At 65 degrees north latitude, the absorbing constituent extends to altitudes above the 50-millibar pressure level.