Group 2 ITI Consensus Report: Technological developments in implant prosthetics.

OBJECTIVES: Group-2 reviewed the scientific evidence in the field of «Technology¼. Focused research questions were: (1) additive versus subtractive manufacturing of implant restorations; (2) survival, complications, and esthetics comparing prefabricated versus customized abutments; and (3) survival of posterior implant-supported multi-unit fixed dental prostheses. MATERIALS AND METHODS: Literature was systematically screened, and 67 publications could be critically reviewed following PRISMA guidelines, resulting in three systematic reviews. Consensus statements were presented to the plenary where after modification, those were accepted. RESULTS: Additively fabricated implant restorations of zirconia and polymers were investigated for marginal/internal adaptation and mechanical properties without clear results in favor of one technology or material. Titanium base abutments for screw-retained implant single crowns compared to customized abutments did not show significant differences concerning 1-year survival. PFM, veneered and monolithic zirconia implant-supported multi-unit posterior fixed dental prostheses demonstrated similar high 3-year survival rates, whereas veneered restorations exhibited the highest annual ceramic fracture and chipping rates. CONCLUSIONS: For interim tooth-colored implant single crowns both additive and subtractive manufacturing are viable techniques. The clinical performance of additively produced restorations remains to be investigated. Implant single crowns on titanium base abutments show similar clinical performance compared to other type of abutments; however, long-term clinical data from RCTs are needed. The abutment selection should be considered already during the planning phase. Digital planning facilitates 3D visualization of the prosthetic design including abutment selection. In the posterior area, monolithic zirconia is recommended as the material of choice for multi-unit implant restorations to reduce technical complications.

Randomized controlled pilot study comparing small buccal defects around dental implants treated with a subepithelial connective tissue graft or with guided bone regeneration.

AIM: To compare subepithelial connective tissue grafts (SCTG) versus guided bone regeneration (GBR) for the treatment of small peri-implant dehiscence defects in terms of profilometric (primary outcome), clinical, and patient-reported outcome measures (PROMs). METHODS: Sixteen patients who presented with small buccal bone dehiscences (≤3 mm) following single implant placement were recruited. Following implant placement, buccal bone defect sites were randomly treated either with a SCTG or GBR. Six patients who lacked bone dehiscences after implant placement were assigned to a negative control. Transmucosal healing was applied in all patients. Patients were examined prior (T1) and after (T2) implant placement, at suture removal (T3), at implant impression (T5), at crown delivery (T6), and 12 (T7) months after crown delivery. Measurements included profilometric outcomes, marginal bone levels, buccal bone and soft tissue thickness, PROMs, and clinical parameters. All data were analyzed descriptively. RESULTS: The median changes in buccal contour as assessed by profilometric measures between T1 and T5 showed a decrease of 1.84 mm for the SCTG group and 1.06 mm for the GBR group. Between T2 and T7, the median change in the buccal contour amounted to 0.45 mm for SCTG and -0.94 mm (=loss) for GBR. Patients' pain perception tended to be higher in SCTG than in GBR. All peri-implant soft tissue parameters showed healthy oral tissues and no clinically relevant differences between groups. CONCLUSION: Within the limitations of this pilot study, treating small peri-implant dehiscence defects with a SCTG might be a viable alternative to GBR. The use of a SCTG tended to result in more stable profilometric outcomes and comparable clinical outcomes to GBR. However, patient-reported outcome measures tended to favor GBR.

Erratum: Self-Diffusion in Amorphous Silicon [Phys. Rev. Lett. 116, 025901 (2016)].

This corrects the article DOI: 10.1103/PhysRevLett.116.025901.

Assessment of long-term habituation correlates in event-related potentials using a von Mises model.

In our preliminary work we were able to demonstrate habituation by analyzing attention correlates in single-trial sequences of auditory event-related potentials (ERPs). Despite different quantitative studies of instantaneous phase of ERPs in long-term habituation, there have been no former studies in generative process underlying the distribution of instantaneous phase information in the context of long-term habituation and its relation to attentional binding. For this means we used a von Mises model, representing the phase information over a set of single trial responses. Additionally we use a quantitative neurofunctional model to predict the dynamics of the instantaneous phase in single-trial ERP data during the long-term habituation. Measured habituation data is used to cross-validate the model's prediction. We conclude that the described method allows for an assessment of dynamic changes in the course of long-term habituation. The results also reinforce our neurofunctional multiscale model of long-term habituation and show the applicability of the described method for the experimental/clinical neurodiagnostic assessment of attentional binding.

Dysfunctional cortical inhibition in adult ADHD: neural correlates in auditory event-related potentials.

In recent times, the relevance of an accurate diagnosis of attention-deficit/hyperactivity disorder (ADHD) in adults has been the focus of several studies. No longer considered a pathology exclusive to children and adolescents, and taking into account its social implications, developing enhanced support tools for the current diagnostic procedure becomes a priority. Here we present a method for the objective assessment of ADHD in adults using chirp-evoked, paired auditory late responses (ALRs) combined with a two-dimensional ALR denoising scheme to extract correlates of intracortical inhibition. Our method allows for an effective single-sweep denoising, thus requiring less trials to obtain recognizable physiological features, useful as pointers of cortical impairment. Results allow an optimized diagnosis, reduction of data loss and acquisition time; moreover, they do not account exclusively for critical elements within clinical evaluations, but also allow studying the pathophysiology of the condition by providing objective information regarding impaired cortical functions.

On the objective assessment of the auditory brainstem response measurement quality.

Auditory Brainstem Responses (ABRs) are commonly used in clinical practice to determine hearing impairments and hearing thresholds. Although many research groups work on automatic recognition of ABRs - in order to decrease the acquisition times - measures to determine the quality of ABR measurements objectively are still missing. In fact, recently released new standards for electroencephalographic measurements in auditory examinations require an objective measurement quality assessment for neurodiagnostic devices. Thus there is a pressing need for the development and evaluation of such a quality control. In this study, we propose (a) a novel technique for the assessment of the ABR measurement quality and (b) evaluate and compare this technique to two other approaches which have been suggested in literature as required by the new standards.

[Complementary oligonucleotide invasion into (CA/TG)31-repetitive region of linear and circular DNA duplexes].

(CA/TG)n-repeats belong to microsatellite DNA and are the most widespread among dinucleotide repeats in mammalian genomes, occupying 0.25% of the genome. These repeats are known to be recombination "hot spots", however the molecular mechanisms of this effect are not known. We proposed that the high frequency of recombination in the repetitive regions may be due to duplex conformational characteristics resulting from a special geometry of base-stacking contacts, which permits the initiation of an invasion process of single-stranded DNA into the duplex homologous region. Here we show for the first time a DNA-DNA interaction of oligonucleotides d(CA)10 and d(TG)10 with linear and circular duplexes containing (CA/TG)31-repeats, upon incubation at 37 degrees C in the absence of proteins. Using radioactively labeled oligonucleotides, we showed that duplex-oligonucleotide interaction intensities depend on their molar ratio at a duplex concentration 30 nM. Decreasing the duplex concentration to 3 nM did not influence the intensity of oligonucleotide invasion. It was shown that more than 1%, but much less than 10% of the duplexes participate in the interaction with oligonucleotides, assuming that one molecule of the duplex interacts with one molecule of the oligonucleotide. Analysis of the kinetics of the process reveals invasion of d(CA)10 at the first minute of its incubation with the duplex, while d(TG)10 interacts with the duplex at an even higher rate. We discuss the role of DNA conformation plasticity of (CA/TG)n-repeats in the phenomenon observed, as well as its biological significance, in particular the role of CA-microsatellites in the initiation of homologous recombination.

High affinity binding of proteins HMG1 and HMG2 to semicatenated DNA loops.

BACKGROUND: Proteins HMG1 and HMG2 are two of the most abundant non histone proteins in the nucleus of mammalian cells, and contain a domain of homology with many proteins implicated in the control of development, such as the sex-determination factor Sry and the Sox family of proteins. In vitro studies of interactions of HMG1/2 with DNA have shown that these proteins can bind to many unusual DNA structures, in particular to four-way junctions, with binding affinities of 10(7) to 10(9) M(-1). RESULTS: Here we show that HMG1 and HMG2 bind with a much higher affinity, at least 4 orders of magnitude higher, to a new structure, Form X, which consists of a DNA loop closed at its base by a semicatenated DNA junction, forming a DNA hemicatenane. The binding constant of HMG1 to Form X is higher than 5 x 10(12) M(-1), and the half-life of the complex is longer than one hour in vitro. CONCLUSIONS: Of all DNA structures described so far with which HMG1 and HMG2 interact, we have found that Form X, a DNA loop with a semicatenated DNA junction at its base, is the structure with the highest affinity by more than 4 orders of magnitude. This suggests that, if similar structures exist in the cell nucleus, one of the functions of these proteins might be linked to the remarkable property of DNA hemicatenanes to associate two distant regions of the genome in a stable but reversible manner.

DNA loops and semicatenated DNA junctions.

BACKGROUND: Alternative DNA conformations are of particular interest as potential signals to mark important sites on the genome. The structural variability of CA microsatellites is particularly pronounced; these are repetitive poly(CA). poly(TG) DNA sequences spread in all eukaryotic genomes as tracts of up to 60 base pairs long. Many in vitro studies have shown that the structure of poly(CA). poly(TG) can vary markedly from the classical right handed DNA double helix and adopt diverse alternative conformations. Here we have studied the mechanism of formation and the structure of an alternative DNA structure, named Form X, which was observed previously by polyacrylamide gel electrophoresis of DNA fragments containing a tract of the CA microsatellite poly(CA). poly(TG) but had not yet been characterized. RESULTS: Formation of Form X was found to occur upon reassociation of the strands of a DNA fragment containing a tract of poly(CA). poly(TG), in a process strongly stimulated by the nuclear proteins HMG1 and HMG2. By inserting Form X into DNA minicircles, we show that the DNA strands do not run fully side by side but instead form a DNA knot. When present in a closed DNA molecule, Form X becomes resistant to heating to 100 degrees C and to alkaline pH. CONCLUSIONS: Our data strongly support a model of Form X consisting in a DNA loop at the base of which the two DNA duplexes cross, with one of the strands of one duplex passing between the strands of the other duplex, and reciprocally, to form a semicatenated DNA junction also called a DNA hemicatenane.

Tumor angiogenesis is associated with progression after radical prostatectomy in pT2/pT3 prostate cancer.

BACKGROUND: The clinical relevance of tumor angiogenesis has been investigated in several human tumor types. Angiogenesis (measured as microvessel density; MVD) was recently correlated with tumor stage, grade, and clinical course in prostate cancer (PC). However, considerable controversy remains concerning the prognostic value of angiogenesis in PC. METHODS: We examined MVD in primary PCs to further establish the prognostic relevance of angiogenesis in this tumor entity. In 98 paraffin-embedded PCs of various stages, 5 prostate adenomas, and 20 normal prostate tissues, MVD was determined immunohistochemically using a polyclonal antibody against factor VIII. The findings were correlated with the clinical data of the patients. RESULTS: Normal prostate tissue and prostate adenomas had a low MVD. In PC, MVD increased significantly with tumor stage and grade (P < 0.001). The Wilcoxon rank statistics showed significant differences for MVD (P < 0.0001), tumor stage (P < 0. 0027), and grade (P < 0.0001), but not for preoperative prostate-specific antigen values in PC patients with and without tumor progression subsequent to treatment, respectively. Importantly, multivariate survival analysis revealed that MVD and tumor grade were the only independent markers for progression in prostate carcinoma. CONCLUSIONS: In this study, tumor angiogenesis measured by MVD was associated with a dismal pathologic appearance and a negative clinical prognosis in PC after radical prostatectomy.

Association of double-stranded DNA fragments into multistranded DNA structures.

We have previously observed that double-stranded DNA fragments containing a tract of the tandemly repeated sequence poly(CA). poly(TG) can associate in vitro to form stable complexes of low electrophoretic mobility, which are recognized with high specificity by proteins HMG1 and HMG2. The formation of such complexes has since been observed to depend on interactions of DNA with polypropylene surfaces, with the suggestion that the formation of low mobility complexes might be the result of strand dissociation followed by misaligned reassociation of the repetitive sequences. The data presented here show that at high ionic strength the interactions of DNA with polypropylene are sufficiently strong for DNA to remain bound to the polypropylene surface, which suggests that DNA might also be involved in interactions with hydrophobic molecules in vivo. Under such conditions, low-mobility complexes are found only in the material adsorbed to the polypropylene surface, and all DNA fragments are able to form low-mobility structures, whether or not they contain repetitive sequences. Preventing the separation of strands by ligating hairpin loop oligonucleotides at both ends of the fragments does not prevent the formation of low-mobility complexes. Our results suggest two different pathways for the formation of complexes. In the first, dissociation is followed by misaligned reassociation of repetitive sequences, yielding duplexes with single-stranded end regions that associate to form multimeric complexes. In the second, repetitive as well as nonrepetitive DNA molecules bound to polypropylene adopt a conformation with locally unwound regions, which allows interactions between neighboring duplexes adsorbed on the surface, resulting in the formation of low-mobility complexes.

Ureteritis and cholecystitis: two unusual manifestations of cytomegalovirus disease in renal transplant recipients.

BACKGROUND: Common clinical manifestations of cytomegalovirus (CMV) infection include flu-like symptoms with fever, diarrhea, leukopenia, and elevated liver enzymes. Diagnosis is made by detection of the virus by buffy-coat blood culture or by polymerase chain reaction (PCR) analysis. METHODS: Here we describe two renal transplant recipients who presented with unusual manifestations of CMV disease (cholecystitis and ureteritis). In both patients, no symptoms or signs of systemic CMV infection were present, and they were thought to have other common causes for cholecystitis and ureteral obstruction. RESULTS: Retrospective analysis of peripheral blood by PCR analysis was positive for CMV DNA. Histologic examination of the resected gall bladder and stenotic ureteric segment showed CMV inclusions, confirmed subsequently by in situ hybridization. Thus, we report that CMV infection may present with acute cholecystitis or ureteral obstruction without its classical clinical symptoms. CONCLUSIONS: Because CMV infection is common in transplant patients, the atypical manifestations of CMV should be considered in the differential diagnosis of posttransplant complications. Detection of CMV DNA in the peripheral blood by PCR analysis may help identify these patients.

115 kDa protein from Xenopus laevis embryos recognized by antibodies directed against the Xenopus homeoprotein XIHbox 1.

Using antibodies against homeoprotein XIHbox 1 from Xenopus laevis, we have detected a new embryonic protein with a much larger molecular weight, 115 kDa. Antibodies fractionated according to their affinity for 3 different domains of the XIHbox 1 protein were used to show that this new protein is related to the C-terminal region of XIHbox 1 protein, downstream from the homeodomain. By immunohistochemistry, the protein was shown to be localized in nuclei of embryonic cells. On SDS-polyacrylamide gels, the 115 kDa protein appears as a set of closely spaced bands whose pattern varies with the stage of development and with the parental origin of the embryos. The protein could be extracted from embryos in a multiprotein complex of approximately 600 kDa. In contrast, the 18 and 27 kDa proteins predicted from the sequence of cloned cDNA to be transcribed and translated from the XIHbox 1 gene could not be detected, suggesting that they are rare or unstable in embryos. These data suggest that the new protein is involved in the development of Xenopus embryos, with a function possibly related to that of the homeoprotein XIHbox 1.

Dialysis adequacy indices in high membrane transporters treated with short-dwell peritoneal dialysis.

Treatment of high-membrane transporters with continuous ambulatory peritoneal dialysis (CAPD) is associated with ineffective ultrafiltration, increased dialysate protein loss, lower serum albumin levels, and lower protein catabolic rates, suggesting development of inadequate dialysis. The use of short-dwell nightly intermittent peritoneal dialysis (NIPD) and daytime ambulatory peritoneal dialysis (DAPD) has not been evaluated. Patients with inadequate ultrafiltration secondary to rapid membrane transport [peritoneal equilibration test (PET) confirmation] were managed with NIPD and DAPD (group A, n = 32) and compared to patients on CAPD and continuous cycling peritoneal dialysis (CCPD) (group B, n = 53) after at least 3 months of therapy. Groups A and B were similar in age, gender, diabetic status, prestudy months on peritoneal dialysis (PD), and residual renal function. No significant differences were observed between the groups with respect to serum albumin, daily protein loss, normalized protein catabolic rate (PCRN), or weekly KT/V urea indices. Diabetics demonstrated lower levels of serum albumin and PCRN than nondiabetics while maintaining equivalent KT/V urea indices. Reassessment of patients 6 months later also revealed no differences in outcome measures between group A (n = 20) and group B (n = 36). High transporters treated with NIPD and DAPD appear to have similar dialysate protein loss, adequacy, and nutrition indices when compared to patients on CAPD and CCPD. Future studies will determine if delivery of higher target small-solute clearances benefits patients on NIPD/DAPD as contrasted with continuous PD modalities (CAPD/CCPD), or diabetics compared to nondiabetics.

Identity of the RNA-binding protein K of hnRNP particles with protein H16, a sequence-specific single strand DNA-binding protein.

Protein H16, which we have identified previously in mammalian cell lines, binds in vitro to two single stranded DNA sites on the late strand of the early promoter of SV40. It has no other single strand binding site in the SV40 genome and does not bind to double stranded DNA. In vitro, H16 can be shown to stimulate strongly the activity of purified RNA polymerase II. Here we have purified this 70 kDa protein from cultured monkey cells and have sequenced three of its tryptic peptides. The analysis indicates that H16 is the simian homolog of human protein K, a nuclear RNA-binding protein found in heterogeneous nuclear ribonucleoprotein (hnRNP) particles, which contains a KH domain present in several proteins including the fragile X mental retardation gene product (FMR1). The binding affinities of protein K/H16 for RNA and DNA were subsequently compared in detail. They showed that under conditions where K/H16 binds strongly to its single stranded DNA site, it binds very weakly to the corresponding RNA sequence. This result suggests a possible shuttling of the protein from RNA to DNA during processes which involve opening of the DNA double helix.

Association of poly(CA).poly(TG) DNA fragments into four-stranded complexes bound by HMG1 and 2.

The tandemly repeated DNA sequence poly(CA).poly(TG) is found in tracts up to 60 base pairs long, dispersed at thousands of sites throughout the genomes of eukaryotes. Double-stranded DNA fragments containing such sequences associated spontaneously with each other in vitro, in the absence of protein, forming stable four-stranded structures that were detected by gel electrophoresis and electron microscopy. These structures were recognized specifically by the nuclear nonhistone high mobility group (HMG) proteins 1 and 2 as evidenced by gel retardation. Such sequence-specific complexes might be involved in vivo in recombination or other processes requiring specific association of two double-stranded DNA molecules.

Site-specific proteolytic cleavage of Ku protein bound to DNA.

Ku protein, a relatively abundant nuclear protein associated with DNA of mammalian cells, is known to be a heterodimer with subunits of 85 and 72 kDa which binds in vitro to DNA ends and subsequently translocates along the molecule. The functional role played by this protein in the cell, however, remains to be elucidated. We have observed here that Ku protein, purified from cultured monkey cells, is the target of specific endoproteolysis in vitro, by which the 85 kDa subunit is cleaved at a precise site while the 72 kDa subunit remains intact. This cleavage releases an 18 kDa polypeptide and converts Ku protein into a heterodimer composed of the 72 kDa subunit associated with a 69 kDa fragment from the 85 kDa subunit. The proteolyzed form of Ku protein, denoted Ku', has DNA binding properties similar to those of Ku protein. The proteolytic mechanism, which is inhibited by leupeptin and chymostatin, is extremely sensitive to ionic conditions, in particular to pH, being very active at pH 7.0 and completely inhibited at pH 8.0. In addition, cleavage occurs only when Ku protein is bound to DNA, not free in solution. We suggest that in vivo, such proteolysis might be necessary for Ku protein function at some stage of the cell cycle.

Hypertonic saline compresses: therapy for complicated exit-site infections.

We review our experience with hypertonic saline compress therapy in 17 patients with complicated peritoneal dialysis catheter exit-site infections (ESIs). Compresses consisted of exit-site application of 4-5 gauze pads soaked with warm 3% saline for 5-10 minutes, three times daily, for 2-4 weeks, followed by once-daily use thereafter. The mechanism of action involves inhibition of bacterial growth by a hypertonic medium. Eleven patients with cultures positive for Staphylococcus aureus or Pseudomonas were treated with local exist-site measures (cleansers, antiseptics, antibiotic ointments). Therapy, which included multiple courses of systemic antibiotics, failed in 8 patients; in 3 patients, who were intolerant to antibiotics, ESI remained unresolved after local care only. Six patients with culture-negative ESIs received no systemic antibiotics and were unimproved following local therapy. Factors associated with therapy failure included malnutrition, diabetes, obesity, and dermal sensitization and injury associated with prolonged topical agent use. Following hypertonic saline compress therapy, we observed resolution of ESI in all patients without recurrence for follow-up intervals of 3-12 months (mean 6.5 months). Advantages of this therapy include excellent patient acceptance, ease of use, lack of adverse effects on exit site, adjacent skin, catheter or systemic reaction, and minimal expense. Future potential applications include routine daily use for infection prophylaxis and as therapy combined with antibiotics for established ESIs.

Short-dwell peritoneal dialysis: increased use and impact on clinical outcome.

We reviewed 216 patients on peritoneal dialysis over a 3-year period to assess the effects on patient outcome of short-dwell dialysis (SDD), defined as dwell time below 4 hours with a daily dry (empty peritoneum) interval. Forty-nine patients (23%) required SDD for improved management of ultrafiltration failure (82%), effective blood pressure control (8%), abdominal wall hernia (4%), hydrothorax (4%), and patient convenience (2%). Ultrafiltration failure was recognized as the inability to achieve resolution of clinical overhydration, confirmed by the peritoneal equilibration test (PET), demonstrating high membrane glucose transport (absorption) and observed retention of dialysate volume. Daytime ambulatory peritoneal dialysis (DAPD) was used by 69% of patients and nightly peritoneal dialysis (NPD) with cyclers by 31%. Only one patient (hydrothorax) transferred to hemodialysis. Observations include sustained hydration and blood pressure control in all patients with maintenance of biochemical dialysis adequacy, less reliance on very hypertonic solutions, an increase in dry weight in 25% of patients, decreased use of antihypertensive agents, effective management of hernia and hydrothorax in 3 of 4 patients, and satisfactory patient tolerance of DAPD and NPD regimens, and daily dry intervals. Factors promoting SDD include improved understanding of PET studies, use of disconnect systems, and improvement in cycler design. We anticipate increasing use of SDD as recognition of its usefulness and application techniques expands.