Molecular and phenotypic characterization of near isogenic lines at QTL for quantitative resistance to Leptosphaeria maculans in oilseed rape (Brassica napus L.).

The most common and effective way to control phoma stem canker (blackleg) caused by Leptosphaeria maculans in oilseed rape (Brassica napus) is by breeding resistant cultivars. Specific resistance genes have been identified in B. napus and related species but in some B. napus cultivars resistance is polygenic [mediated by quantitative trait loci (QTL)], postulated to be race non-specific and durable. The genetic basis of quantitative resistance in the French winter oilseed rape 'Darmor', which was derived from 'Jet Neuf', was previously examined in two genetic backgrounds. Stable QTL involved in blackleg resistance across year and genetic backgrounds were identified. In this study, near isogenic lines (NILs) were produced in the susceptible background 'Yudal' for four of these QTL using marker-assisted selection. Various strategies were used to develop new molecular markers, which were mapped in these QTL regions. These were used to characterize the length and homozygosity of the 'Darmor-bzh' introgressed segment in the NILs. Individuals from each NIL were evaluated in blackleg disease field trials and assessed for their level of stem canker in comparison to the recurrent line 'Yudal'. The effect of QTL LmA2 was clearly validated and to a lesser extent, QTL LmA9 also showed an effect on the disease level. This work provides valuable material that can be used to study the mode of action of genetic factors involved in L. maculans quantitative resistance.

Development of crop-specific transposable element (SINE) markers for studying gene flow from oilseed rape to wild radish.

The screening of wild populations for evidence of gene flow from a crop to a wild related species requires the unambiguous detection of crop genes within the genome of the wild species, taking into account the intraspecific variability of each species. If the crop and wild relatives share a common ancestor, as is the case for the Brassica crops and their wild relatives (subtribe Brassiceae), the species-specific markers needed to make this unambiguous detection are difficult to identify. In the model oilseed rape (Brassica napus, AACC, 2n = 38)-wild radish (Raphanus raphanistrum, RrRr, 2n = 18) system, we utilized the presence or absence of a short-interspersed element (SINE) at a given locus to develop oilseed rape-specific markers, as SINE insertions are irreversible. By means of sequence-specific amplified polymorphism (SINE-SSAP) reactions, we identified and cloned 67 bands specific to the oilseed rape genome and absent from that of wild radish. Forty-seven PCR-specific markers were developed from three combinations of primers anchored either in (1) the 5'- and 3'-genomic sequences flanking the SINE, (2) the 5'-flanking and SINE internal sequences or (3) the SINE internal and flanking 3'-sequences. Seventeen markers were monomorphic whatever the oilseed rape varieties tested, whereas 30 revealed polymorphism and behaved either as dominant (17) or co-dominant (13) markers. Polymorphic markers were mapped on 19 genomic regions assigned to ten linkage groups. The markers developed will be efficient tools to trace the occurrence and frequency of introgressions of oilseed rape genomic region within wild radish populations.

Five-year results of maxillary intramobile Zylinder implants.

We retrospectively analysed the time-dependent function of 501 Intramobile Zylinder (IMZ) implants inserted between August 1983 and December 1994 to restore partially and fully edentulous maxillae. To ensure the independence of implants when calculating level of significance, we chose one implant per patient at random. This was done 500 times to obtain a representative result. The simplified success rate was 473/501 (92%) whereas the time-related survival probability was 76% after 60 months. In 31% (156/500) of the life-table calculations, implants placed in completely edentulous maxillae showed a significantly lower probability of survival than did those placed in partially edentulous patients (P mean: 0.17; SD: 0.19). Implants, that had been placed in the anterior and premolar regions of edentulous maxillae, had a survival probability of 60%, after 60 months. The survival probability of implants placed in the molar region was 100%, over the same observation period. The patient's age, sex, and the time of placement of the implant after tooth extraction had no significant influence on the implant's prognosis. The prognosis of implants inserted for partial edentulism meets the criteria proposed for a viable implant system. Our findings indicate that in complete edentulous maxillae, implants should be placed in the posterior rather than in the anterior region, even though this necessitates augmentation procedures such as sinus lift.

Elimination of bacteria on different implant surfaces through photosensitization and soft laser. An in vitro study.

Microbiologic examinations of implants have shown that certain microorganisms described as periodontal pathogens may have an influence on the development and the progression of peri-implant disease. This experimental study aimed to examine the bactericidal effect of irradiation with a soft laser on bacteria associated with peri-implantitis following exposure to a photosensitizing substance. Platelets made of commercially pure titanium, either with a machined surface or with a hydroxyapatite or plasma-flame-sprayed surface or with a corundum-blasted and etched surface, were incubated with a pure suspension of Actinobacillus actinomycetemcomitans or Porphyromonas gingivalis or Prevotella intermedia. The surfaces were then treated with a toluidine blue solution and irradiated with a diode soft laser with a wave length of 905 nm for 1 min. None of the smears obtained from the thus treated surfaces showed bacterial growth, whereas the smears obtained from surfaces that had been subjected to only one type of treatment showed unchanged growth of every target organism tested (P < 0.0006). Electron microscopic inspection of the thus treated platelets revealed that combined dye/laser treatment resulted in the destruction of bacterial cells. The present in vitro results indicate that lethal photosensitization may be of use for treatment of peri-implantitis.

Survival of 1,920 IMZ implants followed for up to 100 months.

A total of 1,920 IMZ implants, placed between March 1984 and December 1993, were evaluated retrospectively. The Kaplan-Meier cumulative survival rate of the implants was 89.9% after 60 months and 83.2% after 100 months. Life table analysis revealed a statistically significantly lower cumulative survival rate for maxillary implants (71.6% at 60 months and 37.9% at 100 months) than for mandibular implants (90.4% at 100 months). Implants placed in the anterior region of the maxilla failed significantly more often than those placed in the posterior region. This was not observed in the mandible. The age and sex of the patients, the status of the jaw (edentulous, partially edentulous), the time of implant placement in relation to tooth extraction, and the length and diameter of the implants had no statistically significant influence on the cumulative survival rate.

Inhibition of the alveolar macrophage oxidative burst by a diffusible component from the surface of the spores of the fungus Aspergillus fumigatus.

BACKGROUND: Aspergillus fumigatus is a fungus that grows on dead and decaying organic matter in the environment and whose spores are present ubiquitously in the air. The fungus causes a range of diseases in the human lung. A study was undertaken to demonstrate and partially characterise an inhibitor of the macrophage respiratory burst from the surface of A fumigatus spores that could be an important factor in allowing the fungus to colonise the lung. METHODS: The spore-derived inhibitor of the respiratory burst of rat alveolar macrophages, as measured by generation of superoxide anion, was demonstrated in Hank's balanced salt solution extracts of four clinical isolates and an environmental isolate of A fumigatus. The time course of the release of the inhibitor into aqueous solution was assessed and the cytotoxic potential of the spore-derived inhibitor towards macrophages was tested using the propidium iodide method. An oxygen electrode was used to confirm the superoxide anion measurements. Molecular weight cutoff filters were used to determine the size of the inhibitor as assessed in the respiratory burst assay and also by its ability to inhibit macrophage spreading on glass. The crude diffusate from the spore surface was fractionated by reversed phase high pressure liquid chromatography (HPLC) and the fractions analysed for inhibitory activity, protein, and carbohydrate content. RESULTS: A small molecular weight (< 10 kD) heat stable toxin was released from the spores of clinical and environmental isolates of A fumigatus within minutes of deposition in aqueous solution. The key effect of the toxin demonstrated here was its ability to inhibit the oxidative burst of macrophages as measured by superoxide anion release. The inhibition was not due to cell death or detectable loss of membrane integrity as measured by permeability to propidium iodide. The toxin was not a scavenger of superoxide anion. Oxygen electrode studies suggested indirectly that the inhibitor acted to inhibit the assembly of the macrophage NADPH-oxidase complex. Fractions of < 10 kD also inhibited the spreading of alveolar macrophages, confirming that the toxin had an additional effect on macrophages that leads to loss of adherence or impairment of cytoskeletal function. In reversed phase HPLC fractions the inhibitory activity eluted with an associated carbohydrate, although the exact chemical nature of the toxin remains to be elucidated. CONCLUSIONS: This spore toxin may, through its ability to diffuse rapidly into lung lining fluid, diminish the macrophage respiratory burst and play a part in allowing A fumigatus to persist in the lung and manifest its well known pathogenic effects. Future research will be focused on further molecular characterisation of the toxin and elaboration of the effect of the toxin on intracellular signalling pathways involved in the activation of alveolar macrophages.

Immediate and delayed implantation for complete restoration of the jaw following extraction of all residual teeth: a retrospective study comparing different types of serial immediate implantation.

From April 1986 to September 1993, 134 implants (97 immediate implants, 26 early secondary immediate implants, and 11 late secondary implants) were placed in 20 patients following extraction of all residual teeth. After a mean follow-up period of 27.1 months, the implants were analyzed with regard to peri-implant soft tissue parameters and bone resorption. When the examination was performed, 131 implants (97.7%) were found to be functioning successfully. The mean pocket depths varied between 1.3 and 2.6 mm, and the peri-implant bone resorption showed values between 0.5 and 1.3 mm. Fixed and removable prostheses revealed equal results with regard to the parameters examined. The results of the present study indicate that serial immediate implantation can be considered to be a very promising implant treatment modality for serial teeth extraction, if specific parameters are taken into account.

Examination of the damping behavior of IMZ implants.

The damping behavior of 392 IMZ implants with a diameter of 4 mm was examined by performing Periotest measurements during regular implant follow-up. The results were correlated with radiographically assessed peri-implant bone reduction. To guarantee statistical independence, only one randomly chosen implant per patient was considered in the examination. In 167 implants, the difference between the mean mandibular and maxillary Periotest values proved to be statistically significant. Age, sex, and radiographic length of the endosseous part of the abutment had no influence on the Periotest values. Assessment of the Periotest values can thus be considered an additional parameter for objective determination of IMZ implant success. However, exclusive use of the Periotest method without additional radiographic examinations does not seem to be justified.

Brånemark single tooth implants: a preliminary report of 76 implants.

Seventy-six Brånemark single-tooth implants were inserted over a 6-year period. Two implants (2.63%) were removed during the follow-up period. All other implants received esthetic and functional single tooth crowns placed on a single tooth abutment or a CeraOne abutment. The most common complication observed was abutment screw loosening, which occurred with 12 crowns. However, it was possible to clearly reduce the occurrence of screw loosening by applying a defined torque. Peri-implant parameters were investigated on 56 implants that were in place for more than 1 year. Acceptable implant function was demonstrated with preestablished clinical parameters and radiographs. Despite the submucosal edge of the crown, peri-implant mucositis was not a major problem. The favorable clinical and esthetic results found in the study encourage an increased application of implants for single tooth restorations.

[Advantages of microsurgical apicoectomy and retro-preparation with ultrasound compared with current apicoectomy]. / Vorteile der mikrochirurgischen Apexresektion und Retropräparation mittels Ultraschall gegenüber der herkömmlichen Wurzelspitzenresektion.

From September 1992 to March 1994 at the Department of Oral Surgery of the Dental School of the University of Vienna a total of 218 microsurgical apicoectomies and ultrasonic retro-preparations were carried out in 142 patients. Among other indications for operation was the failure of previous surgical-endodontic procedures in 62 cases. In 51 teeth (82%) of these patients the cause of failure could be evaluated with the help of the microscope. Twelve teeth (19%) extracted afterwards showed a longitudinal root fracture which had not been diagnosed before. In all other teeth retro-preparation and filling with zincoxide-eugenol cement was possible, even in cases of difficult anatomic approach. Due to the excellent experiences with microsurgical technique in apicoectomies, the use of the microscope in other fields of dental surgery remains only a matter of time.

[Follow-up of tooth vitality with laser Doppler flowmetry in transplanted teeth]. / Die Vitalitätskontrolle mittels Laser-Doppler-Flowmetrie bei transplantierten Zähnen.

21 autotransplanted teeth were examined by using laser Doppler flowmetry (LDF) at 1, 2, 3, 6 and 12 postoperative weeks. 20 teeth showed statistically significantly higher perfusion units up to the 6th weeks as compared to the control group. At 12 postoperative weeks, the perfusion values of the autotransplanted teeth were at the same level as those of the control group. It was possible to show a non-revascularisation of one tooth with LDF. Currently, LDF can be considered as the only practicable, non-invasive method to evaluate the revascularization of autotransplanted teeth.

Evidence for somatostatin-containing fibers projecting from the pallidal complex to the striatum of the rat.

The origin of afferent somatostatin-containing fibers terminating in medial and ventral parts of the striatum has been investigated by performing various neurochemical and surgical lesions in the rat. Lesions of the anterior hypothalamus, amygdala, and the hippocampal commissure as well as lesions with 6-hydroxydopamine and 5,7-dihydroxytryptamine failed to decrease striatal somatostatin levels. However, thermal coagulation of the globus pallidus or knife-cut lesions performed ventrally to the striatum resulted in significant decreases in striatal somatostatin content. Analysis of the topographical distribution of somatostatin within the striatum after thermal lesions of the globus pallidus as well as after kainic acid-induced seizures revealed a preferential loss of the peptide in medial and ventral portions of the striatum, the site of terminating afferent somatostatin nerve fibers. The data suggest that the striatal afferent somatostatin-containing neurons may originate in the area of the globus pallidus.