Effects of Class II treatment with a banded Herbst appliance on root lengths in the posterior dentition.

INTRODUCTION: The aim of this study was a retrospective analysis of posterior teeth in 20 adolescents and young adults with Angle Class II Division 1 malocclusion treated with a banded Herbst appliance to check for inhibited root development and apical root resorption. METHODS: Panoramic radiographs were taken of every patient at the beginning and after the completion of functional orthopedic treatment. The magnification of the area of the posterior teeth was determined individually for every radiograph. Then the vestibular lengths of the molars and premolars were assessed metrically. To assess root-length changes, the difference between the lengths of the teeth before and after treatment was calculated. RESULTS: After treatment with a banded Herbst appliance, tooth length generally increased in the area of the anchorage. But there was a tendency toward root-length decrease in teeth immediately adjacent to the Herbst fittings in the vestibular roots of both the maxillary first molars (distovestibular, -0.02 ± 2.31 mm; mesiovestibular, -0.06 ± 2.05 mm) and the mandibular first premolars (-0.46 ± 3.53 mm). CONCLUSIONS: The banded Herbst appliance might deliver unphysiologic forces to immediate anchor teeth, thereby exposing these to a higher risk of root resorption than in other teeth incorporated into the anchorage either directly via bands or indirectly via occlusal or approximal contacts. Looking at uncompromised root morphology in the area of the anchorage, we believe that early treatment with fixed functional appliances can be predicted to yield better outcomes than late treatment because of the higher biologic tolerance expressed by teeth with an apical latency.

Efficiency of a skeletonized distal jet appliance supported by miniscrew anchorage for noncompliance maxillary molar distalization.

INTRODUCTION: Conventional anchorage appliances rely exclusively on intraoral anchorage for noncompliance molar distalization. The partial coverage of the palate, in particular, often results in compromised oral hygiene. An innovative alternative combines a skeletonized distal jet appliance with 2 paramedian miniscrews for additional anchorage. The objectives of this study were to investigate the suitability of the skeletonized distal jet for translatory molar distalization and to check the quality of the supporting anchorage setup. METHODS: Two paramedian miniscrews (length, 8-9 mm; diameter, 1.6 mm) were placed into the anterior area of the palate in 10 patients. Skeletonized distal jet appliances fitted with composite to the first premolars and the collars of the miniscrews were used for bilateral molar distalization, and the coil springs were activated with a distalization force of 200 cN on each side. RESULTS: The study confirmed the suitability of the appliance for translatory molar distalization (3.92 +/- 0.53 mm) with slight mesial inward rotation (on average, 8.35 degrees +/- 7.66 degrees and 7.88 degrees +/- 5.50 degrees ). The forces acting reciprocally on the anchorage setup were largely absorbed by the anchorage unit involving 2 anchorage teeth and 2 miniscrews. Significant anchorage loss, in the form of first premolar mesialization of 0.72 +/- 0.78 mm, was found. CONCLUSIONS: The skeletonized distal jet appliance supported by additional miniscrew anchorage allows translatory molar distalization. Although the anchorage design combining 2 miniscrews at a paramedian location and the periodontium of 2 anchorage teeth does not offer the quality of stationary anchorage, it achieves greater molar distalization in total sagittal movement than conventional anchorage designs with an acrylic button.

Why whales are big but not bigger: Physiological drivers and ecological limits in the age of ocean giants.

The largest animals are marine filter feeders, but the underlying mechanism of their large size remains unexplained. We measured feeding performance and prey quality to demonstrate how whale gigantism is driven by the interplay of prey abundance and harvesting mechanisms that increase prey capture rates and energy intake. The foraging efficiency of toothed whales that feed on single prey is constrained by the abundance of large prey, whereas filter-feeding baleen whales seasonally exploit vast swarms of small prey at high efficiencies. Given temporally and spatially aggregated prey, filter feeding provides an evolutionary pathway to extremes in body size that are not available to lineages that must feed on one prey at a time. Maximum size in filter feeders is likely constrained by prey availability across space and time.

Biomechanics of a Distal Jet appliance. Theoretical considerations and in vitro analysis of force systems.

OBJECTIVE: To analyze the forces and moments acting in the first molar region, induced by the Distal Jet appliance for maxillary molar distalization. MATERIALS AND METHODS: Over a working section of 3 mm with reactivation of the loaded spring systems, the force systems of three laboratory-fabricated appliances of identical design were analyzed with a 3D metering device. RESULTS: The force systems registered in vitro exhibited complex biomechanics. Regular reactivation of the loaded coils resulted in consistent distalizing forces and uprighting moments, in forces and moments toward buccal as well as slightly intrusive forces, and mesial-inwardly rotating moments. In the sagittal dimension, the Distal Jet appliance allows almost translatory molar distalization. Accordingly, applying uprighting activation is not necessary for treatment. Because of the application of the force palatal to the center of resistance of the molars, the teeth experience undesired mesial-palatal and distal-facial rotation. CONCLUSIONS: The Distal Jet appliance allows almost translatory distal molar movement, and uprighting activation is not necessary for treatment. The force applied palatal to the center of resistance of the molars produces an undesired mesial-palatal and distal-facial rotation. Regular intraoral coil spring reactivation is needed.

Treatment effects of intraoral appliances with conventional anchorage designs for non-compliance maxillary molar distalization: a literature review.

Since the end of the 1970s, various appliances with intramaxillary anchorage for distalization of the upper molars have been described as an alternative to headgear. The major advantages of these innovative appliances are that they act permanently and are independent of patient compliance. The purpose of this study was to compare the efficiency, both quantitatively and qualitatively, of various appliance types with intramaxillary anchorage for non-compliance molar distalization. Eighty-five papers were reviewed, and 22 were identified as being suitable for inclusion. The selection was based on compliance with the following criteria: treatment group with at least 10 non-syndromal patients, conventional intraoral anchorage design using a palatal button and anchorage teeth, consistent cephalometric measurements in clinical-epidemiological studies, exact data on the course of treatment, and statistical presentation of the measured outcomes and their standard deviations. The results show that non-compliance molar distalization is possible with numerous different appliances. While molar distalization with standard pendulum appliances exhibited the largest values for dental-linear distalization, it also resulted in concurrent, substantial therapeutically undesirable distal tipping. However, specific modifications to the pendulum appliance allow achievement of almost bodily molar distalization. Different outcomes are quoted in the studies for the efficiency of loaded spring systems for distal molar movement, but it seems that the first class appliance and the palatal distal jet are more efficient than the vestibular Jones Jig. The studies identify anchorage loss as being found in the area of the incisors rather than the area of the first premolars. There was a trend for more substantial reciprocal side-effects to occur when only two teeth were included in the anchorage unit. Vertical components acting on the molars, premolars, and incisors, such as intrusion and extrusion, tended to be of secondary importance and, therefore, may be disregarded.

Molar distalization with pendulum appliances in the mixed dentition: effects on the position of unerupted canines and premolars.

INTRODUCTION: The pendulum appliance allows for rapid molar distalization without the need for patient compliance. Its efficiency has been confirmed in a number of clinical studies. However, the potential interactions and positional changes between the deciduous molars used for dental anchorage and the erupted and unerupted permanent teeth have yet to be clarified when this appliance is used for molar distalization in the mixed dentition. METHODS: Twenty-nine patients in the mixed dentition each received a modified pendulum appliance with a distal screw and a preactivated pendulum spring for bilateral distalization of the maxillary molars. The patients were divided into 4 groups based on dentition stages: patient group 1 (PG 1, n = 10) was in the early mixed dentition; patients had resorption of the distal root areas of the deciduous molars being used for dental anchorage, and the unerupted premolars were located at the distal margin of the deciduous molar root region. Based on radiographs taken before placement of the pendulum appliance, patient group 2 (PG 2, n = 10) was diagnosed as having a central location of the unerupted premolars. In the third group (PG 3, n = 4), the first premolars were already erupted and could be integrated into the dental anchorage, but the canines were not yet erupted. In the fourth group (PG 4, n = 5), the first premolars and both canines were fully erupted. RESULTS: Statistical analysis of the measured results showed significant differences in the side effects between PG 1 and PG 2. In patients being treated with pendulum appliances, the anchorage quality of the deciduous molars that were already partially resorbed in the distal root area was comparatively reduced. Consequently, the mesial drift of the deciduous molars and incisors was increased, without impairing the extent and quality of the molar distalization. Anchorage loss in the supporting area had no direct impact on the sagittal position of the unerupted premolars in the early mixed dentition. CONCLUSIONS: If permanent teeth have already started to erupt in the supporting area, additional space restrictions should be avoided in patients with critical topography, especially if there is little space for the unerupted canines. At this stage of the mixed dentition, premolar extraction or augmentation of the supporting area with extraoral headgear offers a therapeutic alternative to intraoral distalization appliances with exclusively dental anchorage.

Molar distalization with a modified pendulum appliance--in vitro analysis of the force systems and in vivo study in children and adolescents.

The standard pendulum appliance was modified by integrating a distal screw into its base and by special preactivation of the pendulum springs. The suitability of this Pendulum K for the translatory distalization of maxillary molars was investigated in an in vitro analysis and in an in vivo study in children and adolescents. The in vitro measurement of the resulting force systems revealed that all forces and moments remained virtually constant over a three-mm simulated distalization increment. The transverse force, Fx, increased from two to 11 cN and the weakly intrusively acting force, Fy, from six to eight cN, but these increases were not statistically significant. The distalization force, Fz, initially 201 cN, was still 199 cN after a three-mm distalization increment. The mesially acting moment, My, rose from 1654 to 1834 cN mm, whereas the palatally acting moment, Mz, declined slightly from 229 to 164 cN mm. The slight, consistent distoinclinatory moment, Mx, initially 306 cN mm, was 310 cN mm after three mm. In parallel, the in vivo study with its collective of 66 patients confirmed that the Pendulum K allows a virtually translatory molar distalization with slight tippings of 4.75 degrees to the palatal plane and 4.25 degrees to the anterior basal plane. Palatal movements of the first molars were avoided. The proportion of molar distalization in the total movement was 73.53%.

Interaction of synthetic D-6-deoxy-myo-inositol 1,4,5-trisphosphate with the Ca2(+)-releasing D-myo-inositol 1,4,5-trisphosphate receptor, and the metabolic enzymes 5-phosphatase and 3-kinase.

The ability of D-6-deoxy-myo-inositol 1,4,5-trisphosphate [6-deoxy-Ins(1,4,5)P3], a synthetic analogue of the second messenger D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3], to mobilise intracellular Ca2+ stores in permeabilised SH-SY5Y neuroblastoma cells was investigated. 6-Deoxy-Ins(1,4,5)P3 was a full agonist (EC50 = 6.4 microM), but was some 70-fold less potent than Ins (1,4,5)P3 (EC50 = 0.09 microM), indicating that the 6-hydroxyl group of Ins(1,4,5)P3 is important for receptor binding and stimulation of Ca2+ release, but is not an essential structural feature. 6-Deoxy-Ins(1,4,5)P3 was not a substrate for Ins (1,4,5)P3 5-phosphatase, but inhibited both the hydrolysis of 5-[32P]+ Ins (1,4,5)P3 (Ki 76 microM) and the phosphorylation of [3H]Ins(1,4,5)P3 (apparent Ki 5.7 microM). 6-Deoxy-Ins (1,4,5)P3 mobilized Ca2+ with different kinetics to Ins(1,4,5)P3, indicating that it is probably a substrate for Ins (1,4,5)P3 3-kinase.

Occurrence of anti-low density lipoprotein antibodies and circulating immune complexes in aged subjects.

The incidence of circulating immune complexes, anti-low density lipoprotein (LDL) autoantibodies and the anti-LDL activity of immune complexes was studied in healthy young and aged controls and in patients with vascular diseases. Circulating immune complexes (CIC) frequently occurred both in the young or old patient groups and in the aged healthy control groups, whereas they could not be found in the young controls. Marked differences were found in the incidence of anti-LDL antibodies between the groups tested. In both young and aged control groups such antibodies were very rarely observed (4-5%). In contrast anti-LDL antibodies were present in 35-45% in the aged, or young patients. Similarly, no anti-LDL activity was found in CIC of the controls, whereas in the patients with vascular diseases a significant CIC-associated anti-LDL activity was detected. These results suggest that the presence of anti-LDL antibodies are associated with the arteriosclerotic manifestations, while that of circulating immune complexes is connected by the ageing process itself.

Studies on the occurrence of circulating immune complexes in vascular diseases.

The presence of circulating immune complexes was studied in 347 samples of serum from 212 patients with various vascular diseases. Two quantitative methods (complement-consumption assay and C1q-solubility test) were used for the measurement of the concentration of the complexes. Immune complexes were detected in each group of patients tested (coronary arteriosclerosis, myocardial infarction, cerebral artery sclerosis, arteriosclerosis obliterans, phlebothrombosis, pulmonary infarction). A high proportion of positivity was recorded in myocardial infarction (in 43 patients out of the 94 tested) and in arteriosclerosis obliterans (7 out of 11 cases). The possible pathogenic role of the circulating immune complexes is discussed.

The effect of clofibrate and pyridinol carbamate on the circulating immune complexes and cellular immune response in experimental atherosclerosis.

Cholesterol-fed rabbits were treated with clofibrate, pyridinol carbamate and with both drugs simultaneously. The quantity of circulating immune complexes in the sera of the animals was measured weekly and the migration inhibition test was carried out in the 12th week of the experiment. The trend of the changes in the concentration of the immune complexes was rather similar to that of the cellular immune response. Compared with the values obtained in the control animals, in the cholesterol-fed group a markedly higher level of immune complexes and a significant migration inhibition could be detected. The administration of clofibrate or pyridinol carbamate alone had no effect on the concentration of immune complexes. Pyridinol carbamate did not influence the migration inhibition; however, it became similar to the healthy controls in the clofibrate-treated group. Simultaneous treatment with both drugs resulted in a decrease in the quantity of immune complexes and a diminution of the migration inhibition.

Free and complexed anti-lipoprotein antibodies in vascular diseases.

The cell-mediated immune response against low density lipoproteins (LDL) was demonstrated by the migration inhibition test in patients with various vascular diseases. Anti-high density lipoprotein2 (HDL2) cellular immune response was found only in a few patients. LDL and HDL2 binding factors were detected in about 50% of coronary patients. No significant difference in their occurrence was found between the normolipidemic and hyperlipidemic patients nor between patients with hyperlipidemia type II/b and type IV. On the assumption that lipoproteins may act as auto-antigens by forming immune complexes, the presence of anti-LDL and anti-HDL2 activity was investigated in circulating immune complexes obtained by polyethylene glycol (PEG) precipitation from the sera of coronary patients and controls. Using an ELISA technique, PEG-precipitable anti-LDL activity was detected in 23, 11 and 18% of cases with myocardial infarction, angina pectoris and healthy old subjects, respectively. In the immune complexes obtained from the sera of the healthy young donors no anti-LDL activity was found. Anti-HDL2 activity in the immune complexes was demonstrated only in a few cases from among the patients and elderly persons we investigated.

Total synthesis of uracil analogues of sinefungin.

Analogues of sinefungin derivatives 18a and 18b have been prepared from uridine and L-aspartic acid. The key step in the synthesis was the coupling of the radical derived from 14 with the unsaturated amide 13. The latter was produced from the known N-hydroxy-2-thiopyridone ester of L-aspartic acid 12 with the olefin 11. Thus, the essential carbon skeleton was constructed by way of two radical coupling reactions. These analogues as well as 1a and 1b synthesized previously were tested for their antileishmanial effect in vivo and for their inhibitory activity of protein carboxymethylase (protein methylase II). The replacement of the adenine moiety by uracil or dihydrouracil considerably decreases the antiparasitic activity and the affinity for protein methylase II. The synthetic (S)-sinefungin was as active as the natural one. Interestingly, the C-6' epimer 1b was 50% less active in vitro than the natural sinefungin, but both had identical affinities for the target enzyme.

Sub-unit assembly in the biosynthesis of neomycin. The synthesis of 5-O-beta-D-ribofuranosyl and 4-O-beta-D-ribofuranosyl-2,6-dideoxystreptamines.

The preparation of the deoxy- analogues of two pseudodisaccharide fragments of neomycin, 5-O-beta-D-ribofuranosyl-2,6-dideoxy-streptamine and 6-deoxyneamine is described. When added to the growth medium of a deoxystreptamine-idiotroph of Streptomyces rimosus forma paromomycinus only the latter was incorporated into antibiotic, suggesting an obligatory order for the assembly of sub-units. 4-O-beta-D-Ribofuranosyl-2,6-dideoxystreptamine was also prepared. When added to the growth medium of a deoxystreptamine-idiotroph of Streptomyces fradiae it was converted into the 6-deoxyneomycins, apparently after hydrolysis to 2,6-dideoxystreptamine. The structure of the protected derivatives of the ribofuranosyl 2,6-dideoxystreptamines, potentially useful intermediates for the synthesis of novel antibiotics, was shown by using 15C NMR spectroscopy.

1-N-acylation of gentamicin C1a by a cyclic, chiral gamma-amino-alpha-hydroxy acid related to the (S)-4-amino-2-hydroxybutyric acid.

A semisynthetic aminoglycoside antibiotic 15, containing a cyclic gamma-amino-alpha-hydroxy acid, related to the 1-N-4-amino-2-hydroxybutyric acid (AHBA) side chain of butirosins and amikacin, has been prepared. Conveniently protected 3,2',6'-tris-N-tert-butoxycarbonylgentamicin C1a (12) was condensed with the phtalimido active ester 10 to give after catalytic reduction and deprotection, the hitherto unknown 1-N-substituted gentamicin C1a 15. The requisite side chain was synthesized from the readily available D-(-)-quinic acid. The antibacterial properties of 15 are given.

Role of the 1-amino group in aminocyclitol antibiotics: synthesis of 1-deaminogentamicin C2.

The synthesis of 1-deaminogentamicin C2 described here, uses 3,2',6',3"-tetrakis-N-tert-butoxycarbonylgentamicin C2 (2) as intermediate. N-Formylation of 2 followed by per-O-acetylation and dehydration furnished the isocyanide 5. Radical-induced deamination of the latter using tri-n-butylstannane and removal of the protecting groups afforded the target 1-deaminogentamicin C2 (7). Its in vitro antibacterial activity is less than that of the parent gentamicin C2. The behaviour of 7 towards aminoglycoside-inactivating enzymes was also examined; interestingly, it was found to be neither substrate nor inhibitor for such enzymes. These results strongly suggest that the substitution pattern of the 1-position determines the biological properties of the aminoglycoside antibiotics.