A 5-year randomized trial to compare 1 or 2 implants for implant overdentures.

The hypothesis of this 5-y randomized clinical trial was that there would be no significant difference in the satisfaction of edentulous participants with removable complete overdentures attached to 1 or 2 mandibular implants. Secondary aims were to test changes in satisfaction between and within the groups from baseline to 5 y and differences between the groups in implant survival and prosthodontic maintenance over 5 y. Each of the 86 participants (mean age, 67 y) was randomly allocated to receive either 1 implant in the midline (group 1) or 2 implants in the canine areas (group 2) attached to a mandibular overdenture opposing a maxillary complete denture. Satisfaction was self-assessed by participants on a visual analog scale at baseline prior to implants, as well as at 2 mo and 1, 3, and 5 y with implant overdentures, whereas implant survival and prosthodontic maintenance were assessed by clinical examination. After 5 y, 29 participants in group 1 and 33 in group 2 were available, with most dropouts due to death. Satisfaction with the implant denture after 5 y was significantly (P < 0.001) higher than at baseline in both groups and remained with no significant difference (P = 0.32) between the groups. No implants failed in group 1 but 5 failed before loading in 4 participants in group 2. Most participants required maintenance or occasionally denture replacement, and although differences between the groups were not statistically significant, group 1 experienced almost twice as many fractured dentures usually adjacent to the implant attachment. We conclude that there were no significant differences after 5 y in satisfaction or survival of implants with mandibular overdentures retained by 1 implant or 2 implants. Additional research is required to confirm long-term treatment effectiveness of single-implant dentures and the implications of prosthetic maintenance with implant overdentures (ClinicalTrials.gov: NCT02117856).

Predicting body temperature and activity of adult Polyommatus icarus using neural network models under current and projected climate scenarios.

We use field observations in two geographic regions within the British Isles and regression and neural network models to examine the relationship between microhabitat use, thoracic temperatures and activity in a widespread lycaenid butterfly, Polyommatus icarus. We also make predictions for future activity under climate change scenarios. Individuals from a univoltine northern population initiated flight with significantly lower thoracic temperatures than individuals from a bivoltine southern population. Activity is dependent on body temperature and neural network models of body temperature are better at predicting body temperature than generalized linear models. Neural network models of activity with a sole input of predicted body temperature (using weather and microclimate variables) are good predictors of observed activity and were better predictors than generalized linear models. By modelling activity under climate change scenarios for 2080 we predict differences in activity in relation to both regional differences of climate change and differing body temperature requirements for activity in different populations. Under average conditions for low-emission scenarios there will be little change in the activity of individuals from central-southern Britain and a reduction in northwest Scotland from 2003 activity levels. Under high-emission scenarios, flight-dependent activity in northwest Scotland will increase the greatest, despite smaller predicted increases in temperature and decreases in cloud cover. We suggest that neural network models are an effective way of predicting future activity in changing climates for microhabitat-specialist butterflies and that regional differences in the thermoregulatory response of populations will have profound effects on how they respond to climate change.

A computer-assisted measurement technique to assess bone proximal to oral implants on intraoral radiographs.

A computer-assisted measurement technique for measuring bone levels proximal (mesial and distal) to oral implants imaged on standardized intraoral radiographs offers promise for accuracy and reliability. There were no differences between bone measurements made directly from bone proximal to implants placed in a dry mandible and those resulting from the computer-assisted measurement technique. In addition, there were no differences between measurements made of bone proximal to oral implants in vivo using the microscope and the computer techniques. The computer technique had a low intra- and inter-operator variability, and operators found fewer "unreadable" sites compared to the microscope technique. The computer-assisted measurement of bone levels proximal to oral implants on standardized intraoral radiographs offers accuracy and reliability.

Thermal ecology of gregarious and solitary nettle-feeding nymphalid butterfly larvae.

Group-living in animal populations has many possible ecological and evolutionary explanations, including predator evasion and feeding facilitation. In insects, the thermal balance of solitary and gregarious larvae is likely to differ and may thus have important ecological consequences. The abilities of the larvae of four species of nettle-feeding nymphalid butterflies to thermoregulate were quantified in the field. Larval surface body temperatures of the gregarious Aglais urticae (small tortoiseshell) and Inachis io (peacock) and the solitary Polygonia c-album (comma) and Vanessa atalanta (red admiral) were measured for each instar, in both sunny and overcast conditions, over a seasonal range of temperatures. The results suggested two distinct larval thermal strategies. In the presence of direct sunlight, the exposed gregarious larvae of A. urticae and I. io regulated body temperatures at 32.5 and 31.5°C, respectively, while the temperatures of concealed larvae of P. c-album and V. atalanta were largely dependent on ambient temperatures. In the sun, the range of body temperatures recorded for A. urticae and I. io larvae was fairly narrow relative to ambient temperatures. This suggests a high degree of thermal control in these species. Modal body temperatures coincided with the temperature at which development rate is maximal. Regardless of whether changes in thermoregulation are a cause or consequence of the evolution of gregariousness, the combination of behavioural thermoregulation and gregariousness in larval insects has important implications for voltinism patterns and range extension (via increased development rates). Distributional responses of gregarious and solitary larvae to climatic warming may differ as a result of changes in cloud cover as well as changes in temperature.

Soluble transforming growth factor-beta type II receptor inhibits negative remodeling, fibroblast transdifferentiation, and intimal lesion formation but not endothelial growth.

Using the rat balloon catheter denudation model, we examined the role of transforming growth factor-beta (TGF-beta) isoforms in vascular repair processes. By en face in situ hybridization, proliferating and quiescent smooth muscle cells in denuded vessels expressed high levels of mRNA for TGF-beta1, TGF-beta2, TGF-beta3, and lower levels of TGF-beta receptor II (TGF-betaRII) mRNA. Compared with normal endothelium, TGF-beta1 and TGF-beta2, as well as TGF-betaRII, mRNA were upregulated in endothelium at the wound edge. Injected recombinant soluble TGF-betaRII (TGF-betaR:Fc) localized preferentially to the adventitia and developing neointima in the injured carotid artery, causing a reduction in intimal lesion formation (up to 65%) and an increase in lumen area (up to 88%). The gain in lumen area was largely due to inhibition of negative remodeling, which coincided with reduced adventitial fibrosis and collagen deposition. Four days after injury, TGF-betaR:Fc treatment almost completely inhibited the induction of smooth muscle alpha-actin expression in adventitial cells. In the vessel wall, TGF-betaR:Fc caused a marked reduction in mRNA levels for collagens type I and III. TGF-betaR:Fc had no effect on endothelial proliferation as determined by reendothelialization of the denuded rat aorta. Together, these findings identify the TGF-beta isoforms as major factors mediating adventitial fibrosis and negative remodeling after vascular injury, a major cause of restenosis after angioplasty.

Vascular remodeling in response to altered blood flow is mediated by fibroblast growth factor-2.

Vascular structures adapt to changes in blood flow by adjusting their diameter accordingly. The factors mediating this process are only beginning to be identified. We have recently established a mouse model of arterial remodeling in which flow in the common carotid artery is interrupted by ligation of the vessel near the carotid bifurcation, resulting in a dramatic reduction in vessel diameter as a consequence of inward remodeling and intimal lesion formation. In the present study, we used this model to determine the role of fibroblast growth factor-2 (FGF-2) in the remodeling response by maintaining neutralizing serum levels of a mouse monoclonal antibody against FGF-2 for 4 weeks. Morphometric analysis revealed that intimal lesion formation was not affected by the antibody. However, lumen narrowing was significantly inhibited, resulting in a greater than 3-fold increase in lumen area in anti-FGF-2-treated animals compared with controls. Treatment with anti-FGF-2 antibody significantly inhibited the reduction in vessel diameter (inward remodeling) and shortening of the internal elastic lamina in the ligated vessel. In addition, anti-FGF-2 treatment also caused outward remodeling of the contralateral carotid artery. These findings identify FGF-2 as an important factor in vascular remodeling, and its effects are likely to be mediated by increasing vascular tone. The results are consistent with the recent observation of reduced vascular tone in the FGF-2-deficient mouse.

Osseointegration of oral implants in older and younger adults.

Osseointegration involves an osseous healing response that may be compromised by aging. This study aimed to test the hypothesis that there is no difference between older and younger adults in osseointegration success. A comparison was made between closely matched groups of 39 older adults who had 190 implants supporting 45 oral prostheses and 43 younger adults who had 184 implants supporting 45 oral prostheses. Patients were monitored for a period of 4 to 16 years after prosthetic loading. At the most recent follow-up, the cumulative implant success was 92.0% for the older group compared to 86.5% for the younger group. No statistical significance could be attributed to the difference in implant survival between the groups throughout the study period. Furthermore, the most common outcome for individual prosthetic sites was 100% implant success, and the original prosthetic design was maintained for as long as each patient was monitored in 41 or 45 prosthetic prescriptions for the older patients, and in 39 of 45 prescriptions for the younger patients.

The effects of age, jaw site, and bone condition on oral implant outcomes.

PURPOSE: This paper reviews literature on age and jaw site in relation to jawbone quantity and quality and the osseointegration of endosseous oral implants. RESULTS AND DISCUSSION: The condition of jawbone is both age- and site-specific. However, increased age does not appear to affect the clinical potential for osseointegration or the rate of crestal bone resorption observed around oral implants. In contrast, jaw site is related significantly to osseointegration potential; mandibular sites tend to be more successful than maxillary sites. The reason for this may be that jawbone quality and quantity are often more compromised in maxillary than in mandibular sites. However, evaluation of this relationship has been hampered by a lack of evidence to support the validity and reliability of methods used to assess jawbone condition preoperatively. Furthermore, short-term evidence suggests that high rates of implant success can be achieved in maxillary sites, even those with low trabecular density, if an adequate volume of bone exists to accommodate the implants. Although the rate of crestal bone resorption around oral implants is usually low and may not be site-specific, there is some evidence that it may be greater in sites with less preoperative resorption associated with shorter periods of edentulism. This pattern of bone loss could jeopardize long-term implant outcomes especially in younger implant patients. Another concern in young growing patients is that their prosthetic outcome may become compromised because osseointegrated implants cannot keep pace with growth and development in surrounding structures. CONCLUSION: To improve our understanding of how the age- and site-specificity of jawbone condition affects oral implant outcomes, research needs to be aimed at establishing reliable and valid measures of preoperative jawbone condition, and at better documenting the effects of jawbone condition on oral implant outcomes.

Vascular endothelial growth factor increases the mitogenic response to fibroblast growth factor-2 in vascular smooth muscle cells in vivo via expression of fms-like tyrosine kinase-1.

Vascular endothelial growth factor (VEGF) has traditionally been considered an endothelial cell-specific factor inducing angiogenesis and vascular permeability in vivo. In the present study, expression of VEGF and its receptors, fetal liver kinase-1 (flk-1) and fms-like tyrosine kinase-1 (flt-1), was examined in rat carotid arteries after balloon injury. Although VEGF and flk-1 were not detectable, high levels of flt-1 mRNA and protein were expressed by smooth muscle cells (SMCs) in the neointima, as demonstrated by en face in situ hybridization and Western blotting. Intimal SMC proliferation in chronically denuded rat carotid arteries was unaffected by intraluminal infusion of VEGF, whereas fibroblast growth factor (FGF)-2 increased the number of replicating SMCs 4-fold. Pretreatment with VEGF doubled the mitogenic response to infused FGF-2 by increasing SMC replication in deeper layers of the intima. VEGF increased the permeability of chronically denuded vessels to plasma proteins but had no effect on the uptake of locally infused biotinylated FGF-2. These findings demonstrate that vascular SMCs express functional flt-1 receptors after arterial injury and that VEGF has synergistic effects with FGF-2 on SMC proliferation. These effects are likely to be mediated by a VEGF-mediated increase in permeability as well as a direct interaction between the VEGF and FGF signaling pathways.

Activation of the NF-kappa B and I kappa B system in smooth muscle cells after rat arterial injury. Induction of vascular cell adhesion molecule-1 and monocyte chemoattractant protein-1.

The NF-kappa B transcription factor family and its inhibitory proteins (I kappa B) form an autoregulatory system that has been linked to endothelial gene expression and vascular disease. To determine the role of the NF-kappa B/I kappa B system in smooth muscle cells (SMCs) in vivo, the present study used the balloon catheter injury model in the rat carotid artery. The NF-kappa B family members p50, p65, p52, c-Rel, and RelB as well as the inhibitor proteins I kappa B alpha, I kappa B beta, and p105 were present in uninjured arteries as determined by immunoblotting. Using electromobility shift assays, low levels of constitutively activated p50, p65, and c-Rel were seen in normal carotid arteries and a fivefold induction occurred during times of rapid SMC proliferation and neointima formation after balloon denudation. Furthermore, immediately after injury, the levels of I kappa B alpha, I kappa B beta, and p105 were dramatically reduced. Expression of the NF-kappa B-regulated genes, vascular cell adhesion molecule (VCAM)-1 and monocyte chemotactic protein (MCP)-1, was apparent in SMCs within 4 hours after injury. Macrophage infiltration occurred in parallel with the expression of VCAM-1 and MCP-1, and these inflammatory cells were present on the luminal surface of injured vessels during intimal lesion formation. In chronically denuded vessels, the SMCs on the luminal surface continued to express high levels of VCAM-1 and MCP-1, which may account for the increased presence of macrophages. Together, these findings link the activation of NF-kappa B to intimal lesion formation and to the inflammatory response associated with SMCs after vascular injury.

Ethical issues encountered by dentists in the care of institutionalized elders.

Increasing numbers of institutionalized elders have very poor oral health. It has been suggested that ethical problems may influence dentists who attempt to provide oral care for these people, but little attention has been given to research in this area. A qualitative interview method was used to investigate the the views and experiences of dentists working with institutionalized elders. Particular attention was given to the ethical difficulties encountered and how the dentists resolved them. Ten dentists experienced in long-term care were interviewed individually by means of open-ended questions. Thematic analysis identified ethical problems focused on the difficulty of identifying the wishes of patients or predicting the outcome of treatment. The participants reported few difficulties in making clinical decisions in this setting. However, analysis revealed that the ethical perspectives of the dentists varied substantially. Variation was notable particularly in their preference for ideal or practical treatment and in their preference for autonomy of beneficence.

Antimetabolites of pantothenic acid, ureido- and carbamoyl-derivatives.

Pantothenic acid analogs have been synthesized that contain alkyl and/or arylureido and carbamate functions in the beta-alanyl portion of the amide moiety of the vitamin. The analogs are inhibitory to growth of lactic acid bacteria at concentrations as low as 0.6 mug/ml, and the inhibitions are competitively reversed by supplements of pantothenic acid. The carbamate derivatives are more toxic to growth of Lactobacillus plantarum 8014 and Pediococcus cerevisiae 8042 than the ureido analogs, and chloro-substitutents on the aryl group significantly increase the toxicity of the analogs.

Inhibitory Effects of Dichlorophenoxyacetones on Auxin-induced Growth of Avena Coleoptile Sections.

Six dichlorophenoxyacetones were synthesized and examined as potential metabolic antagonists utilizing Avena coleoptile sections and the straight growth assay procedure. Supplements of indoleacetic acid promoted growth of the sections which were inhibited by the analogs; the most inhibitory derivatives were 2,3-; 2,4-; 2,5-; and 3,4-dichlorophenoxyacetone which produced half-maximal growth responses (relative to the unaug-mented control growth) at concentrations of 106, 86, 80, and 62 mug/ml, respectively. A Lineweaver-Burk plot of the data for the inhibition by 2,4-dichlorophenoxyacetone and its reversal by indoleacetic acid appeared to represent an uncompetitive-like inhibition.