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To evaluate the use of hydrogen peroxide as an adjunct to ultrasonication (US) in biofilm removal and whether it can limit the spread of viable microorganisms in the aerosol.Multi-species biofilms were formed on dentin disks and titanium disks fixed on a plastic surface. After placing the specimens in a periodontal pocket model, an ultrasonic scaler was applied for 30 s, in part combined with 0.25% or 0.5% H2O2. After treatment, the remaining biofilm was analysed for bacterial counts (colony forming units [CFU]), biofilm quantity and metabolic activity. Further, the cytotoxic effect of hydrogen peroxide on periodontal ligament fibroblasts was assessed and the spread of bacteria in aerosol was quantified.Ultrasonication reduced bacterial counts in biofilm, biofilm mass and metabolic activity on both dentin and titanium disks. Adjunctive use of 0.25% and 0.5% H2O2 more effectively reduced the viable bacteria in biofilm than ultrasonication alone; this was also found on both dentin and titanium. The different concentrations of H2O2 did not lead to corresponding differences in bacterial mass and metabolic activity. The spread of bacteria through aerosols was statistically significantly reduced when adjunctive H2O2 was used. However, a certain cytotoxic effect on periodontal ligament fibroblasts by H2O2 could not be ruled out.Irrigating with H2O2 during periodontal instrumentation with an ultrasonic scaler increases the reduction of viable bacteria within biofilms. It might limit bacterial spreading via aerosols.

To evaluate the healing of multiple adjacent type 1 and 2 gingival recessions (RT1 and RT2) treated with the modified coronally advanced tunnel (MCAT) or the laterally closed tunnel (LCT) in conjunction with a cross-linked hyaluronic acid and subepithelial palatal connective tissue grafts.Fifteen healthy patients exhibiting multiple adjacent mandibular or maxillary RT1 and RT2 of a depth of ≥ 2 mm, were treated with the MCAT or LCT in conjunction with cross-linked hyaluronic acid and subepithelial palatal connective tissue grafts. Results were assessed at baseline and after a minimum of 6 months. The primary outcome variable was root coverage. Esthetic outcomes were evaluated on photographs using the root coverage esthetic score.Postoperative pain and discomfort were low and no complications occurred. Data analyses were performed at patient level. After a mean follow-up of 17 ± 5.4 months, statistically significant root coverage was obtained in all 15 cases (P.0001). Complete root coverage was obtained in 3 out of 15 cases (20%). Root coverage amounted to95% in three patients, was between 90% and 95% in four patients, and reached 87.5% in another patient. In three further patients root coverage measured 75%, 77%, and 64.6%, respectively. Mean root coverage measured 85.1 ± 23.2%. Mean keratinized tissue width increased from 2.5 ± 1.0 mm to 3.7 ± 0.7 mm (P.0001) from baseline to follow-up, while mean probing depth showed no statistically significant changes (1.3 ± 0.5 mm vs 1.5 ± 0.5 mm). The mean root coverage esthetic score was 7.9 ± 1.9, while in the three cases exhibiting complete root coverage, a maximum root coverage esthetic score (10) was given for all treated teeth.Within their limits, the present results indicate that the described treatment approach may lead to predictable root coverage of multiple mandibular and maxillary RT1 and RT2.

To clinically evaluate the healing of mandibular Miller Class I and II isolated gingival recessions treated with the modified coronally advanced tunnel (MCAT) or laterally closed tunnel (LCT) combined with hyaluronic acid (HA) and subepithelial connective tissue graft (SCTG).Twelve healthy patients exhibiting one isolated mandibular Miller Class I or II (Cairo Class 1) gingival recession of a depth of ≥ 3 mm, were consecutively treated with the MCAT or LCT in conjunction with HA and SCTG. Treatment outcomes were assessed at baseline and at least 6 months postoperatively. The primary outcome variable was complete root coverage (CRC).Postoperative pain and discomfort were low and no complications such as postoperative bleeding, allergic reactions, abscesses, or loss of SCTG occurred. After a mean follow-up of 18.9 ± 10 months, statistically significant (P.0001) root coverage was obtained in all 12 defects. CRC was measured in six out of the 12 cases (50%), four cases showed a root coverage of over 95%, while the remaining two cases reached 80% and 85%. Mean root coverage was 96.09%. Mean keratinized tissue width increased from 1.6 ± 0.8 mm to 4.9 ± 1.3 mm (P.0001) from baseline to follow-up, while mean probing depth showed no statistically significant changes (1.8 ± 0.9 mm vs 1.3 ± 0.5 mm).Within their limits, the present results indicate that the described treatment approach may lead to predictable root coverage of isolated mandibular Miller Class I and II (Cairo Class 1) gingival recessions. (Quintessence Int 2020;51:456-463; doi: 10.3290/j.qi.a44492).

The aim of the present study was to evaluate both survival and failure rates of endodontically treated teeth restored with or without fiber post-retained restorations after a mean observation period of at least 5 years.A total of 144 single-rooted and multirooted teeth in 100 subjects were endodontically treated following a predetermined aseptic protocol and restored with either a fiber post and a composite core or a composite filling without intraradicular retention. A fiber post was cemented when the teeth presented with only 1 wall and/or less than one third of the remaining height of the clinical crown. After a comprehensive treatment plan, the teeth were restored with either a direct composite restoration or a single-unit crown. Endodontically treated teeth supporting fixed and removable dental prostheses and telescopic crowns were excluded from the analysis. Success was defined as tooth survival without any treatment of biological and/or technical complications.The overall tooth survival rate was 89.6% after a mean observation time of 8.8 ± 2.3 years. The survival rate of teeth with a fiber post amounted to 94.3%, and for teeth without a post, it was 76.3% (P .001). The main reason for tooth loss was root fracture (9.7%). No loss of post retention was observed. Successfully treated teeth without any biological and/or technical complications and requiring no additional treatment during the entire observation period amounted to 79.9%.Endodontically treated teeth restored with fiber posts and either a direct composite restoration or a single-unit crown yielded higher survival and success rates compared with teeth restored without fiber posts. Vertical fractures of roots not containing a post represented a frequently encountered and serious problem.

Additional file of The venom composition of the parasitic wasp Chelonus inanitus resolved by combined expressed sequence tags analysis and proteomic approach

INTRODUCTION The aim of the present study was to evaluate both survival and failure rates of endodontically treated teeth restored with or without fiber post-retained restorations after a mean observation period of at least 5 years. METHODS A total of 144 single-rooted and multirooted teeth in 100 subjects were endodontically treated following a predetermined aseptic protocol and restored with either a fiber post and a composite core or a composite filling without intraradicular retention. A fiber post was cemented when the teeth presented with only 1 wall and/or less than one third of the remaining height of the clinical crown. After a comprehensive treatment plan, the teeth were restored with either a direct composite restoration or a single-unit crown. Endodontically treated teeth supporting fixed and removable dental prostheses and telescopic crowns were excluded from the analysis. Success was defined as tooth survival without any treatment of biological and/or technical complications. RESULTS The overall tooth survival rate was 89.6% after a mean observation time of 8.8 ± 2.3 years. The survival rate of teeth with a fiber post amounted to 94.3%, and for teeth without a post, it was 76.3% (P

The egg-larval parasitoid Chelonus inanitus injects bracoviruses (BVs) and venom along with the egg into the host egg; both components are essential for successful parasitoid development. All stages of eggs of its natural host, Spodoptera littoralis , can be successfully parasitized, i.e. from mainly a yolk sphere to a fully developed embryo. Here, we show that the venom contains at least 25 proteins with masses from 14 kDa to over 300 kDa ranging from acidic to basic. The majority is glycosylated and their persistence in the host is short when old eggs are parasitized and much longer when young eggs are parasitized. Physiological experiments indicated three different functions. (1) Venom synergized the effect of BVs in disrupting host development when injected into third instar larvae. (2) Venom had a transient paralytic effect when injected into sixth instar larvae. (3) In vitro experiments with haemocytes of fourth instar larvae suggested that venom alters cell membrane permeability. We propose that venom promotes entry of BVs into host cells and facilitates placement of the egg in the embryo's haemocoel when old eggs are parasitized. The multifunctionality of the venom might thus be essential in enabling parasitization of all stages of host eggs.

International audience; Very few obligatory relationships involve viruses to the remarkable exception of polydnaviruses (PDVs) associated with tens of thousands species of parasitic wasps that develop within the body of lepidopteran larvae. PDV particles, injected along with parasite eggs into the host body, act by manipulating host immune defences, development and physiology, thereby enabling wasp larvae to survive in a potentially harmful environment. Particle production does not occur in infected tissues of parasitized caterpillars, but is restricted to specialized cells of the wasp ovaries. Moreover, the genome enclosed in the particles encodes almost no viral structural protein, but mostly factors used to manipulate the physiology of the parasitized host. We recently unravelled the viral nature of PDVs associated with braconid wasps by characterizing a large set of nudivirus genes residing permanently in the wasp chromosome(s). Many of these genes encode structural components of the bracovirus particles and their expression pattern correlates with particle production. They constitute a viral machinery comprising a large number of core genes shared by nudiviruses and baculoviruses. Thus bracoviruses do not appear to be nudiviruses remnants, but instead complex nudiviral devices carrying DNA for the delivery of virulence genes into lepidopteran hosts. This highlights the fact that viruses should no longer be exclusively considered obligatory parasites, and that in certain cases they are obligatory symbionts.

In order to fulfil their responsibilities under the precautionary principle, biosafety commissions should lay down guidelines concerning the understanding and application of this principle and work towards an operational procedure. With this contribution, we propose a step-wise procedure that aims to establish the understanding of the precautionary principle within biosafety commissions and to provide a methodological approach for the application of this principle to specific cases in the course of risk assessment. This approach is based on systematically investigating the consensus view within a group of 15 biosafety experts with the help of sets of checklists. For step 1, we propose a checklist of 13 criteria aimed at defining the understanding of the precautionary principle. For step 2, we propose 4 criteria for the decision on whether or not to use the precautionary principle. For step 3, 11 criteria for the use of the precautionary principle are presented. In step 4, additional criteria for specific applications could be included. In step 5, possible recommendations to decision-making authorities are proposed.

Polydnaviruses are symbiotic viruses of endoparasitic wasps, which are formed in their ovary and injected along with the eggs into the host. They manipulate the host in a way to allow successful parasitoid development. A hallmark of polydnaviruses is their segmented genome consisting of several circles of double-stranded DNA. We are studying the solitary egg-larval parasitoid Chelonus inanitus (Braconidae) parasitizing Spodoptera littoralis (Noctuidae). The polydnavirus of Chelonus inanitus (CiV) protects the parasitoid larva from encapsulation by the host’s immune system, slightly modifies host nutritional physiology, and induces a developmental arrest of the host in the prepupal stage. Here we present data on newly identified CiV genes and their expression patterns in the course of parasitization. None of these genes has similarity to other genes and so far no gene families could be found. A rough estimation of transcript quantities revealed that even the most highly expressed CiV genes reach maximal values, which are 250 times lower than actin. This indicates that the CiV-induced alterations of the host are brought about by a concerted action of low levels of transcripts. In an overview, we show the expression patterns of all CiV genes analysed up to now; they indicate that several genes with similar expression patterns (early, persistent, intermediate, or late) are grouped together on the same segment. This is the first observation of this type. It suggests that one function of the segmentation of the polydnavirus genome may be the grouping together of genes, which are regulated in a similar manner. Arch. Insect Biochem. Physiol. 66:9–22, 2007. © 2007 Wiley-Liss, Inc.

Chelonus inanitus is a solitary egg-larval endoparasitoid, which feeds on host haemolymph during its internal phase. Parasitization induces in the host Spodoptera littoralis a precocious onset of metamorphosis and a developmental arrest in the prepupal stage. At this stage the parasitoid larva emerges from the host and consumes it. We show here that parasitization and the co-injected polydnaviruses affect the nutritional physiology of the host mainly in the last larval instar. Polydnaviruses cause a reduced uptake of food and an increase in the concentration of free sugars in the haemolymph and of glycogen in whole body. The parasitoid larva, along with polydnaviruses, causes a reduction of proteins in the host's plasma and an accumulation of lipids in whole body. Dilution of host haemolymph led to a reduced concentration of lipid in parasitoid larvae and a reduced survival rate. Thus, a sufficient concentration of nutrients in the host's haemolymph appears to be crucial for successful parasitoid development. Altogether, the data show that the parasitoid and the polydnavirus differentially influence host nutritional physiology and that the accumulated lipids and glycogen are taken up by the parasitoid in its haematophagous stage as well as through the subsequent external host feeding.

Successful parasitism of some endoparasitic wasps depends on an obligately symbiotic association with polydnaviruses. These unique viruses have a segmented genome consisting of circles of double-stranded (ds) DNA and do not replicate in the parasitized host. They are produced in the wasp's ovary and injected into the host along with the egg. Chelonus inanitus is an egg–larval parasitoid; its polydnavirus (CiV) has been shown to protect the parasitoid larva from the host's immune system and to induce developmental arrest in the prepupal stage. The genome of CiV consists of at least 10–12 segments and five have been sequenced up to now. Here, the complete (CiV12g2) or partial (CiV12g1, CiV16.8g1) cloning of three new CiV genes is reported. All three occur only on one viral segment and have no similarity to other known polydnavirus genes, with the exception of a high similarity of CiV12g1 to CiV14g1 and CiV12g2 to CiV14g2. Furthermore, the first attempt of in vivo application of RNA interference to study the function of polydnavirus genes is shown. Injection of dsRNA of two late- and one early- and late-expressed CiV genes into CiV/venom-containing host eggs partially rescued last-instar larvae from developmental arrest. Injection of the same dsRNAs into parasitized eggs partially reduced parasitoid survival, mainly by preventing the successful emergence of the parasitoid from the host. These viral genes thus seem to be involved in inducing developmental arrest and in keeping the cuticle soft, which appears to be necessary for parasitoid emergence and host feeding.

In situ hybridizations show that 5 min after parasitization, polydnavirus DNA is in close vicinity of the parasitoid egg, but 5 h later also in the yolk and partially in the host embryo. Fifteen hours after parasitization, the viral DNA is seen all over the host embryo and hardly in the yolk. The tissue distribution of the viral DNA was analysed and quantified by dot blots in the fifth instar parasitized larvae. On a per host basis, haemocytes and fat body contained the highest amount of viral DNA, while nervous tissue, intestinal tract and carcass contained less. Of the three viral segments tested, all were found in all tissues. Relative to the quantity of host DNA, viral DNA was most abundant in haemocytes, about five times less abundant in fat body and nervous tissue and about 25 times less abundant in intestinal tract. The total quantity of viral DNA per host was 444 ± 145 pg which is similar to the quantity injected by the wasp; thus, the viral DNA persists throughout parasitization. The parasitoid larva contains 820 ± 80 pg viral DNA integrated in the genome. This illustrates that the dose of viral DNA injected in virions represents approximately one third of the total viral genomic information present in a host at a late stage of parasitism.  2003 Elsevier Science Ltd. All rights reserved.