Bone maintenance 5 to 10 years after sinus grafting

PURPOSE

This radiographic study determined the amount of bone around hydroxyapatite (HA)-coated dental implants that were placed into bone-grafted maxillary sinuses.

PATIENTS AND METHODS

Postoperative complex motion tomograms using the Grossman technique were taken on 16 patients who had 27 maxillary sinus grafts performed using particulate autogenous iliac bone with and without demineralized bone, autogenous iliac corticocancellous block with and without demineralized bone, and autogenous jaw bone with demineralized bone. Bone levels were measured from the new floor of the grafted sinus to the apex of the implant and to the alveolar crest. The resulting bone level measures were compared with the type of graft used. All patients had been restored for 5 to 10 years after simultaneous graft and implant placement.

RESULTS

For all patients summed together, the average amount of bone from the top of the graft to the apex of the implant was 3.3 +/- 3.1 mm, and the average amount of bone from the top of the graft to the alveolar crest was 17.6 +/- 3.1 mm. The average level of bone in the sinuses of patients grafted with autogenous iliac bone was greater than the average level of bone in those grafted with autogenous bone combined with demineralized bone.

CONCLUSION

The results of this study indicate that autogenous bone grafts are maintained in the maxillary sinus, but the results with autogenous bone alone are better than when demineralized bone is added. However, this difference may not be clinically significant.

Differential regional expression and ultrastructural localization of alpha-actinin-2, a putative NMDA receptor-anchoring protein, in rat brain

Fast chemical neurotransmission is dependent on ionotropic receptors that are concentrated and immobilized at specific postsynaptic sites. The mechanisms of receptor clustering and anchoring in neuronal synapses are poorly understood but presumably involve molecular linkage of membrane receptor proteins to the postsynaptic cytoskeleton. Recently the actin-binding protein alpha-actinin-2 was shown to bind directly to the NMDA receptor subunits NR1 and NR2B (), suggesting that alpha-actinin-2 may function to attach NMDA receptors to the actin cytoskeleton. Here we show that alpha-actinin-2 is localized specifically in glutamatergic synapses in cultured hippocampal neurons. By immunogold electron microscopy, alpha-actinin-2 is concentrated over the postsynaptic density (PSD) of numerous asymmetric synapses where it colocalizes with NR1 immunoreactivity. Thus alpha-actinin-2 is appropriately positioned at the ultrastructural level to function as a postsynaptic-anchoring protein for NMDA receptors. alpha-Actinin-2 is not, however, exclusively found at the PSD; immunogold labeling was also associated with filaments and the spine apparatus of dendritic spines and with microtubules in dendritic shafts. alpha-Actinin-2 showed marked differential regional expression in rat brain. For instance, the protein is expressed at much higher levels in dentate gyrus than in area CA1 of the hippocampus. This differential regional expression implies that glutamatergic synapses in various parts of the brain differ with respect to their alpha-actinin-2 content and thus, potentially, the extent of possible interaction between alpha-actinin-2 and the NMDA receptor.

Iliac apophyseal cartilage augmentation of the deficient piriform rim and maxilla in alveolar cleft grafting

This article presents a new approach to cleft lip and cleft palate repair, where the retained bulk of alveolar cleft grafts is augmented by simultaneous cartilage augmentation of the deficient maxilla. Nine patients who provided 10 cleft sites underwent secondary bone grafting of the clefted alveolus by this technique. This study evaluates the following: (1) the postoperative esthetic results, (2) the quantity of bone in the grafted area, and (3) the provision of bone support for unerupted teeth, for teeth adjacent to the cleft, and for orthodontic tooth movement when the secondary bone grafting of the cleft is integrated with the onlay augmentation of the deficient maxilla. Photographic and radiographic investigations were undertaken. The photographic evaluation showed that all patients exhibited improved facial esthetics in the area of the cleft, particularly in the paranasal area of the maxilla; improved alar base support, symmetry of the columella, and less deviation of the tip of the nose were seen. The radiographic evaluation indicated the following: (1) the average percentage of the alveolar bone height of the grafted area was equal to 76% of the normal side; (2) nine canines erupted or were erupting through the grafted area; there were no adequate records to evaluate the fate of the remaining canine; (3) no teeth involved in the cleft area were ankylosed, because of inadequate records, so evaluators could not determine the status of one tooth; (4) all patients had adequate quantity of bone for orthodontic tooth movement through the grafted area; and (5) the periodontal support of the teeth involved in the cleft was adequate.

Film-screen systems: sensitometric comparison of Kodak Ektavision system to Kodak T-Mat/RA system

BACKGROUND

In 1995, Eastman Kodak Company (Rochester, N.Y.) marketed the Ektavision Extraoral Imaging Film and Screen System. It produced high-resolution images by keeping the light emitted by intensifying screens from "punching through" one emulsion layer on the film to another.

OBJECTIVES

The objectives of the experiment were (1) to compare the sensitometric properties of the Ektavision system to its predecessor, the T-Mat/RA system and (2) to determine whether films and screens of the Ektavision and the T-Mat/RA systems could be interchanged without clinically changing the sensitometric properties. Ektavision and Lanex Regular intensifying screens were used in combination with Ektavision, T-Mat G/RA, T-Mat L/RA, and T-Mat H/RA films.

RESULTS

The results showed that the Ektavision film was slightly slower than the T-Mat G/RA film no matter what type of screen was used. The type of screen used had little effect on inherent contrast or exposure latitude. The Ektavision film had approximately similar inherent contrast as the T-Mat G/RA film but less than that of the T-Mat H/RA film; its latitude was less than that of the T-Mat L/RA film. The manufacturer does not recommend combining T-Mat/RA film with Ektavision screens or Lanex Regular screens with Ektavision film because of a possible reduction in image resolution. But this mismatch did not clinically affect inherent contrast and exposure latitude; however, film speed was slightly affected.

CONCLUSIONS

The Ektavision system is the result of advanced technology that produces images of high resolution. The high-resolution Ektavision film is slightly slower than the T-Mat G/RA film but is equivalent to it in its contrast and latitude. Therefore when changing from the combination of T-Mat/RA film plus Lanex Regular screens to that of Ektavision film plus Ektavision screens, a slight increase in x-radiation exposure should be made.

Effects of tomographic motion, slice thickness, and object thickness on film density

The experiment used the computer-aided CommCat model IS 2000 tomographic machine (Imaging Sciences International, Roebling, N.J.). The objective of the experiment was to study the influence of tomographic tube motion, tomographic slice thickness, and object thickness on film density. The experiment was conducted by x-radiating an aluminum step-wedge placed along the x-axis. Exposures were made for different tube motions and for different slice thicknesses. In linear horizontal and linear vertical motions, an increased slice thickness decreased film density. Slice thickness had a stronger effect on film density when the object to be x-radiated was thinner. In circular, elliptical, spiral, and hypocycloidal motions, changes in slice thickness had no noticeable effect on film density because the manufacturer had programmed the machine to produce approximately similar exposure times by increasing the x-ray tube velocity thickness had a greater effect on film density for circular, elliptical, spiral, and hypocycloidal tube motions than for linear horizontal and linear vertical tube motions. Clinical observation showed that except for the linear vertical motion (motion that was oriented in the same direction as that of the tube travel) all other motions produced a zone of diffusion along the edges of the steps of the step-wedge. An increase in slice thickness had an effect on film density. Slice thickness had a noticeable effect on film density in linear but not in multidirectional tomography. Object thickness had a greater effect on film density in multidirectional than in linear tomography.

Effects of developer exhaustion on Kodak EKTASPEED Plus, Ektaspeed, and Ultra-speed dental films

In 1994, Eastman Kodak Co. (Rochester, N.Y.) replaced its Ektaspeed film with the EKTASPEED Plus film. The manufacturer claims that one of the advantages of the new film is that it is not strongly affected by exhausted (depleted plus aged) processing solutions. The objective of the experiment was to test this claim. In exhausted solutions, EKTASPEED Plus film lost its speed more rapidly than Ultra-speed film but less rapidly than Ektaspeed film; that is, Ultra-speed film had the most stable speed. EKTASPEED Plus film lost contrast for 2 weeks before stabilizing, whereas Ultra-speed and Ektaspeed films continued to lose contrast for 3 weeks. Overall, EKTASPEED Plus film held its contrast over the other two films. EKTASPEED Plus film stopped increasing its film latitude after 2 weeks, whereas Ultra-speed and Ektaspeed films continued to increase film latitudes. In conclusion, for the three films studied, EKTASPEED Plus maintained the most constant levels of contrast and latitude in progressively exhausted solutions. All three films lost speed in exhausted solutions; EKTASPEED Plus film was the fastest but Ultra-speed film had the most stable speed.

Sensitometric comparison of Kodak EKTASPEED Plus, Ektaspeed, and Ultra-speed Dental Films

In 1994, Eastman Kodak Co. (Rochester, N.Y.) marketed EKTASPEED Plus dental film to combine the advantages of the contrast of Ultra-speed film and the speed of Ektaspeed film. EKTASPEED Plus film uses T-Grain Emulsion technology similar to that used in the manufacture of the light-sensitive indirect exposure Kodak T-Mat film. This study compared the sensitometric properties of Ultra-speed, Ektaspeed, and EKTASEED Plus dental films. EKTASPEED Plus film was faster than Ektaspeed film at all film densities. Ektaspeed film became slower at higher densities and around a density of 1.9 became even slower than the Ultra-speed film. EKTASPEED Plus film had high inherent contrast and narrow exposure latitude similar to that of Ultra-speed film, whereas Ektaspeed film had low inherent contrast and wide exposure latitude. In conclusion, EKTASPEED Plus film had the advantages of the high contrast of Ultra-speed film and the high speed of Ektaspeed film. It maintained its high speed at high densities.

Information recall of younger and older skilled athletes: the role of display complexity, attentional resources and visual exposure duration

This study was concerned with the interactive role of experience of athletic skill with other relevant environmental variables (display complexity, attentional resources, exposure time of stimuli) on perception (recall) of structured handball game situations. Nineteen experienced (older) and 19 less experienced (younger) handball players were assigned randomly either to ball-bouncing (diverted attention) or to calm seated (focused attention) conditions. In each of the two conditions, the subjects were exposed to a total of 36 slides containing 2-3, 5-6 and 8-10 players. Eighteen slides were exposed for 0.5 s and 18 for 1.0 s. All the slides contained structured defence and offence situations. Recall scores were subjected to repeated-measures ANOVA using attention condition and age as between-subject factors and task complexity and exposure duration as within-subject factors. The results showed that the recall of less experienced players deteriorated more than the recall of more experienced players following exposure to complex displays (> or = 8 players) while engaging in a secondary task (bouncing). The findings suggest that research paradigms should be applied in the field of sport which share both ecological validity and a potential to discover the cognitive substrates underlying experience and age in skilled motor performance.

Characterization of a cleavage mutant of the measles virus fusion protein defective in syncytium formation

Membrane fusion caused by measles virus (MV) is a function of the fusion (F) protein. This process is essential for penetration into the host cell and subsequent initiation of the virus replicative cycle. The biological activity of the MV F protein is generated by endoproteolytic cleavage of a precursor protein (F0) into a large F1 subunit and a smaller F2 subunit held together by disulfide bonds. The cleavage site consists of a cluster of five basic amino acids (amino acids 108 to 112) within the predicted primary structure of the F protein. To investigate the role of the arginine residue at the carboxy terminus of the F2 subunit (arginine 112), site-directed mutagenesis was used to construct a cleavage mutant of the MV F protein in which this arginine residue was changed to a leucine residue. The mutated F gene, encoding four out of the five basic amino acids at the cleavage site, was inserted into the genome of vaccinia virus. The resulting recombinant virus was used to study expression of the mutant F protein in infected cells. Analysis of the Leu-112 mutant protein made in infected cells demonstrated that this single-amino-acid substitution resulted in a reduced rate of transport of the mutant protein to the cell surface, despite its efficient cleavage to yield F1 and F2 subunits. However, the electrophoretic mobilities of the Leu-112 polypeptides suggested that the protein was cleaved incorrectly. This aberrant cleavage appears to have abolished the ability of the F protein to cause syncytium formation. The data indicate that the arginine 112 residue is critical for the correct proteolytic cleavage that is required for the membrane fusion activity of the MV F protein.

Functional analysis of N-linked glycosylation mutants of the measles virus fusion protein synthesized by recombinant vaccinia virus vectors

The role of N-linked glycosylation in the biological activity of the measles virus (MV) fusion (F) protein was analyzed by expressing glycosylation mutants with recombinant vaccinia virus vectors. There are three potential N-linked glycosylation sites located on the F2 subunit polypeptide of MV F, at asparagine residues 29, 61, and 67. Each of the three potential glycosylation sites was mutated separately as well as in combination with the other sites. Expression of mutant proteins in mammalian cells showed that all three sites are used for the addition of N-linked oligosaccharides. Cell surface expression of mutant proteins was reduced by 50% relative to the wild-type level when glycosylation at either Asn-29 or Asn-61 was abolished. Despite the similar levels of cell surface expression, the Asn-29 and Asn-61 mutant proteins had different biological activities. While the Asn-61 mutant was capable of inducing syncytium formation, the Asn-29 mutant protein did not exhibit any significant cell fusion activity. Inactivation of the Asn-67 glycosylation site also reduced cell surface transport of mutant protein but had little effect on its ability to cause cell fusion. However, when the Asn-67 mutation was combined with mutations at either of the other two sites, cleavage-dependent activation, cell surface expression, and cell fusion activity were completely abolished. Our data show that the loss of N-linked oligosaccharides markedly impaired the proteolytic cleavage, stability, and biological activity of the MV F protein. The oligosaccharide side chains in MV F are thus essential for optimum conformation of the extracellular F2 subunit that is presumed to bind cellular membranes.

Subcutaneous low dose arabinosyl-cytosine and oral idarubicin in high risk adult acute myelogenous leukemia

In order to further explore low dose chemotherapy for high risk acute myelogenous leukemia (AML), low dose Ara-C and oral idarubicin (LAI) were given to 33 patients of 24-84 (median 66) years with AML after myelodysplastic syndrome (MDS) (12 patients), refractory AML (13 patients), and AML with contraindications to intensive chemotherapy (8 patients). Patients received 1 to 4 cycles of Ara-C 10 mg/m2 q 12 h s.c. inject. on days 1-14 and idarubicin 20 mg/m2/d orally days 3, 4, 5. Three Three patients attained complete remission, four patients partial remission and one patient minor response, whereas 11 patients succumbed to early mortality from hemorrhage (two patients) and/or infections (10 patients). Three of 13 patients with heavily pretreated refractory AML went into remission compared to 3/12 with AML after MDS and 1/8 with AML and contraindications against intensive treatment. Median duration of CR is 102 (70-488 +) days. Thirty-two of 33 patients developed grade 4 hematological toxicity requiring platelet transfusions. The non-hematologic toxicity was acceptable. LAI provides a standardized therapeutic option especially for heavily pretreated patients with AML.

The relationship between cognitive characteristics and decision making

Team handball players (N = 118) underwent a number of cognitive tests to examine how much of their decision making (DM) ability, as measured through responses to game slides projected to them for 2 seconds under low and high exertion levels (i.e., walking and running), was accounted for by cognitive components. A stepwise multiple linear regression indicated that experience was the most pronounced predictor of DM capacity in both exertion conditions. In the walking condition, concentrational consistency, avoidance of concentrational mistakes, and short-term memory, together with experience, produced a multiple R of 0.48 with decision making. In the running condition, choice reaction time (CRT), intelligence, and short-term memory, together with experience, correlated 0.46 with DM. These differences in cognitive abilities, as predictors of DM under walking and running conditions, are discussed in terms of information processing models and other cognitive processes.

Sensitometric comparison of direct- and indirect-exposure films used in intraoral radiography

In Japan, some dentists use indirect-exposure (screen) films for intraoral radiography, without the use of intensifying screens. The purpose of the present investigation was to determine whether film speed, inherent contrast, and latitude of Japanese indirect-exposure films used without intensifying screens were comparable to those of direct-exposure (non-screen) films used for intraoral radiography. The characteristic curves of Kodak Ektaspeed ("E" speed) and Ultra-speed ("D" speed) films were used as standards for comparison. Indirect-exposure films without intensifying screens were extremely slow compared with direct-exposure "E" and "D" speed films. Therefore, they should not be used for intraoral radiography because they needlessly expose the patient to excessive X-ray radiation. The direct-exposure films Hanshin Hi-Fi and Hanshin New Silver were equivalent in speed, higher in contrast, and narrower in latitude than Kodak Ektaspeed film. In general, the indirect-exposure films had lower speed, lower contrast and wider latitude than the direct-exposure films. Their speed and contrast would have been increased if intensifying screens had been used. Therefore, indirect-exposure films without intensifying screens should not be used for intraoral radiography.

Nonreplicating viral vectors as potential vaccines: recombinant canarypox virus expressing measles virus fusion (F) and hemagglutinin (HA) glycoproteins

The development of canarypox virus (CPV) recombinants expressing the hemagglutinin (HA) and fusion (F) glycoproteins of measles virus (MV) is described. Inoculation of the CPV-MV recombinants into avian or nonavian tissue culture substrates led to the expression of authentic MVF and MVHA as determined by radioimmunoprecipitation and surface immunofluorescence. In contrast to avian-derived tissue culture, no productive replication of the CPV recombinant was evident in tissue culture cells derived from nonavian origin. On inoculation of dogs, a species restricted for avipoxvirus replication, the recombinants elicited a protective immune response against a lethal canine distemper virus (CDV) challenge. The level of MV neutralizing antibodies and the level of protection induced against CDV challenge achieved by the host-restricted CPV vector were equivalent to that obtained by vaccinia virus vectors expressing the same MV antigens.

Automatic processing: effects of temperature and time changes on the sensitometric properties of light-sensitive films

The effects of changes in the processing temperature and time of automatic processors were studied with three light-sensitive Kodak films: (1) blue-sensitive X-Omat RP film, (2) green-sensitive T-Mat G film, and (3) ultraviolet-sensitive X-Omat duplicating film. Speed and inherent contrast were derived for each of the three films from sensitometric curves at six different temperatures and at five different processing times. The T-Mat G film (T-grain technology) was comparatively less sensitive than conventional films (X-Omat RP) to increases in processing temperature or time. Unlike dental intraoral films, which cannot be processed at low processing time or temperature, the light-sensitive films were of archival storage quality even at a low processing time of 2.5 minutes or at a low processing temperature of 21 degrees C. Therefore the processing time of an automatic processor may be decreased for light-sensitive films.

Efficacy of nucleoprotein and haemagglutinin antigens expressed in fowlpox virus as vaccine for influenza in chickens

Fowlpox virus (FPV) recombinants expressing influenza virus H5 haemagglutinin (HA), nucleoprotein (NP) or co-expressing both of these antigens were tested for vaccine efficacy in chickens. Immunization with the recombinant FPV-HA was highly efficacious but provided no cross protection between subtypes. Bursectomy established that immunity against the H5 subtype was antibody-mediated despite the presence of very low levels of antibody in the vaccinated birds. Immunization with the recombinant FPV expressing the cross-reactive NP antigen did not provide protective immunity despite hyperimmunization and provided no benefit above HA expressed alone. The results suggest that the kinetics of viral replication outpaces immunity induced by NP.

Efficacy studies on a canarypox-rabies recombinant virus

Recombinant avipox viruses have been developed expressing the rabies glycoprotein gene. A fowlpox-rabies recombinant has previously been shown to be protective against live rabies virus challenge in a number of non-avian species. This report describes the development of a canarypox-rabies recombinant. A comparison is made of the protective efficacy of this recombinant with other pox-rabies recombinants.