Temporal Changes in Nuclear Envelope Permeability during Semi-Closed Mitosis in Dictyostelium Amoebae.

The Amoebozoan Dictyostelium discoideum exhibits a semi-closed mitosis in which the nuclear membranes remain intact but become permeabilized to allow tubulin and spindle assembly factors to access the nuclear interior. Previous work indicated that this is accomplished at least by partial disassembly of nuclear pore complexes (NPCs). Further contributions by the insertion process of the duplicating, formerly cytosolic, centrosome into the nuclear envelope and nuclear envelope fenestrations forming around the central spindle during karyokinesis were discussed. We studied the behavior of several Dictyostelium nuclear envelope, centrosomal, and nuclear pore complex (NPC) components tagged with fluorescence markers together with a nuclear permeabilization marker (NLS-TdTomato) by live-cell imaging. We could show that permeabilization of the nuclear envelope during mitosis occurs in synchrony with centrosome insertion into the nuclear envelope and partial disassembly of nuclear pore complexes. Furthermore, centrosome duplication takes place after its insertion into the nuclear envelope and after initiation of permeabilization. Restoration of nuclear envelope integrity usually occurs long after re-assembly of NPCs and cytokinesis has taken place and is accompanied by a concentration of endosomal sorting complex required for transport (ESCRT) components at both sites of nuclear envelope fenestration (centrosome and central spindle).

Partial Disassembly of the Nuclear Pore Complex Proteins during Semi-Closed Mitosis in Dictyostelium discoideum.

Dictyostelium cells undergo a semi-closed mitosis, during which the nuclear envelope (NE) persists; however, free diffusion between the cytoplasm and the nucleus takes place. To permit the formation of the mitotic spindle, the nuclear envelope must be permeabilized in order to allow diffusion of tubulin dimers and spindle assembly factors into the nucleus. In Aspergillus, free diffusion of proteins between the cytoplasm and the nucleus is achieved by a partial disassembly of the nuclear pore complexes (NPCs) prior to spindle assembly. In order to determine whether this is also the case in Dictyostelium, we analysed components of the NPC by immunofluorescence microscopy and live cell imaging and studied their behaviour during interphase and mitosis. We observed that the NPCs are absent from the contact area of the nucleoli and that some nucleoporins also localize to the centrosome and the spindle poles. In addition, we could show that, during mitosis, the central FG protein NUP62, two inner ring components and Gle1 depart from the NPCs, while all other tested NUPs remained at the NE. This leads to the conclusion that indeed a partial disassembly of the NPCs takes place, which contributes to permeabilisation of the NE during semi-closed mitosis.

The Dictyostelium Centrosome.

The centrosome of Dictyostelium amoebae contains no centrioles and consists of a cylindrical layered core structure surrounded by a corona harboring microtubule-nucleating γ-tubulin complexes. It is the major centrosomal model beyond animals and yeasts. Proteomics, protein interaction studies by BioID and superresolution microscopy methods led to considerable progress in our understanding of the composition, structure and function of this centrosome type. We discuss all currently known components of the Dictyostelium centrosome in comparison to other centrosomes of animals and yeasts.

Therapeutic Challenge in a Severely Atrophic Mandible.

BACKGROUND: After tooth loss, however, severely atrophic residual alveolar ridges are fairly common, especially in patients who have been edentulous for a long period. Anterior area of the mandible is areas where clinicians have greater anatomical limitations. Reduced alveolar bone height very often represents a contraindication to implant therapy, unless a procedure such as a ridge augmentation is performed. CASE REPORT: This study aims to present two separate cases in highly selected edentulous anterior mandibular sites, where one stage, mini implants were used to support total prostheses. Small diameter implants have been used for retention of complete removable mandibular overdentures. This is an excellent option for those who suffer from the inconvenience and embarrassment of loose lower dentures and are tired of having to use sticky pastes and creams to make their dentures stay in place. CONCLUSION: Small diameter implants, when used multiples may offer adequate support for a removable prosthesis and overcome this problem.

The Effects of NBF Gingival Gel Application in the Treatment of the Erosive Lichen Planus: Case Report.

The therapy of erosive lichen planus (ELP) has been particular problem in the treatment of oral lesions. This case of ELP in male patient 29 years old was treated with topic application of the NBF gingival gel, three times a day after meal, previously rinsed with Clorhexidine gluconate 0.12%. After 5 days of treatment, initial improvements were recorded, and after two weeks of application of the NBF gingival gel we observed significant improvement. Clinical monitoring after the fifth day showed mild epithelialization of the eroded mucosa, yet still present erythematous base of the lesion. After the second week the erythema area was significantly reduced and the eroded surfaces of the mucosa were minimal, measured less than 0.5 mm. After the third week there were no erosions to detect on the oral mucosa, yet still present vague redness, which completely pulled after the fourth week. Treatment ended after the fifth week when the topical application of the NBF gingival gel was terminated, and therapy was done, and clinically achieved effects remained stable even after the third month of the treatment. Topic application of the NBF gingival gel with ELP patients showed positive clinical effects in relatively short time period.

Therapeutic effect of proaftol in treatment of recurrent aphthous stomatitis.

UNLABELLED: Recurrent aphthous stomatitis (RAS) is a quite frequent, painful, ulcerative disease that affects the lining of the oral cavity and has an unknown etiology. The aim of this article is to examine the impact of the medication proaftol on epithelization speed and severity of pain in patients with RAS. In this randomized, double-blind, placebo-controlled study respondents were divided into two groups where one group was treated with proaftol spray and the other with a placebo. Aphthae considered for treatment had a diameter of 5-6 mm. The participants were given instruction on the use of the spray, two sprayings on the place of the aphtae 3-4 times a day. We examined two parameters in the symptomatology of RAS-lesion size (mm) and pain intensity (noted on four subjective levels: 0-no pain, 1-discomfort, 2-moderate pain, 3-severe pain). These parameters were noted on the baseline, the third, the fifth and the eighth days of examination. RESULTS: A significant faster reduction of the dimension of aphthous ulcers in patients treated with proaftol 3rd day p<0.001, 5th day p<0.0006, 8th day full epithelization in the control group. The magnitude of pain in the experimental compared with the control group on 3rd, 5th and 8th day was also significantly reduced: p<0.0001, p<0.007, p<0.007 respectively. CONCLUSION: The use of proaftol positively influences the rate of epithelization and reduction of subjective feeling of pain in patients with RAS. The action of propolis should be the goal of studies with a larger number of subjects.

The role of inflammation and apoptosis in cyclosporine A-induced gingival overgrowth.

Cyclosporin A(CsA) - induced gingival overgrowth(GO) is a current problem of tissue-specific mechanism which is still incompletely explained. The apoptotic process has been of particular interest like a new concept in the etiology of this unwanted effect. The aim of our study was to detect the level of apoptosis, expression bcl-2 and p53, associated with the different doses of CsA. in gingival stroma. A cohort of 84 kidney transplant recipients was divided into four subgroups based on average daily dose of therapeutically applied CsA (Neoral®), (100 mg, 125 mg, 150 mg and 175 mg). The control group consisted of 21 patients, clinically diagnosed with periodontitis, who were not subjected to any medicamentous treatment causing gingival overgrowth. The following indexes were analyzed: plaque index (PI), index of gingival inflammation (GI) according to Loe-Silnes, and gingival overgrowth index (GOI) according to MacGaw et al. The tissue samples were subjected to a semiquantitative analysis to detect apoptotical cells and immunohistochemically stained to detect the expression of the bcl-2 and p53 proteins. The difference in percentage of apoptotic cells between the group taking 175 mg and other subgroups, as well as the control group was statistically significant (p<0.05). There was a significant difference in percentage of expression bcl-2 between the 175 mg group compared to the other three subgroups and the control (p=0.001). However, a statistically significant positive correlation between the medicament dose, p53, apoptosis, and bcl-2 was registered (p<0.05). Inflammation plays the most important role in the induction of apoptosis and proliferation in gingival tissues.

Oral findings in end-stage renal disease.

The aim of the study was to analyse and compare the most frequent clinical oral symptoms, signs and lesions at end-stage renal disease (ESRD), before kidney transplantation (BKT) and after kidney transplantation (AKT). A total of 35 subjects with ESRD were included, 19 in group A (BKT) and 16 in group B (AKT). Oral lesions were classified according to referent clinical diagnostic criteria: Serum albumins, urea, creatinine and salivary urea, creatinine uremic acid were determined by standard biochemical spectrophotometric methods (Human, Germany). For serum albumin concentration measurement (g/L) the method of bromcresol green assay was used while serum and salivary uric acid determination (µmol/L) was performed according the uricase/PAP method. Serum creatinine concentration was measured (µmol/L) with the Jaffe kinetics method, without deproteinization. Oral signs, symptoms and lesions were higher in group A: metallic taste (O.R. = 6.61/ ± 95% CI : 1.13 < O.R. < 38.69), dry mouth (O.R. = 30/ ± 95% CI : 3.15 < O.R. < 285.71), uremic stomatitis (O.R. = 6.5/ ± 95% CI : 1.47 < O.R. < 28.80 and coated tongue (O.R. = 11.73/ ± 95% CI : 2.31 < O.R. < 59.54). On the other hand, in group B, gingival enlargement (O.R. = 59.5/ ± 95% CI : 7.41 < O.R. < 478.05) was more common. High statistically significant differences were recorded between group A and B for dry mouth and gingival enlargement (p > 0.001). Blood urea, creatinine and albumin levels, as well as salivary urea creatinine and uraemic acid values, were significantly higher in group A. Chances of the appearance of all symptoms, clinical signs and lesions, except gingival enlargement, were greater in group A as against group B. Some of our findings correspond with the stage of the disease and some with the use of medicaments in treatment.