Neutral zone approach for the rehabilitation of a severely atrophic mandibular ridge: Case report

Providing a complete denture for a patient with an atrophic mandibular ridge presents a unique challenge for dentists. Retention, stability, and support must be considered when fabricating and fitting a complete denture. This article highlights the use of the neutral zone technique for successful complete denture therapy in a patient with an atrophic mandibular ridge, with special emphasis on the role of coverage of genial tubercles for maximum prosthesis support and stability.     

Development of starch based intelligent films by incorporating anthocyanins of butterfly pea flower and TiO2 and their applicability as freshness sensors for prawns during storage

Intelligent pH sensitive starch films were developed by incorporation of anthocyanin pigment extracted from butterfly pea flower (BPE) and nanosized TiO₂ using the method of solution casting. This research work evaluated the influence of BPE and TiO₂ on the physical and structural properties of starch films. The physical properties of the starch films could be significantly altered by the addition of BPE and or TiO₂. The starch films S/BPE and S/BPE/TiO₂ exhibited higher barrier properties against water vapour as compared to the control films. Incorporation of BPE and TiO₂ could decrease the thickness and moisture content of films. S, S/BPE starch films were transparent and, S/TiO₂ and S/BPE/TiO₂ films were opaque. Control starch films were colourless, whereas S/BPE films have purple colour. Owing to the inclusion of BPE and TiO₂ particles, structural characterization by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) did not show any major changes in polymer structure. Thermogravimetric analysis revealed that the addition of TiO₂ enhanced the thermal stability of starch films to a significant extent. The color of different starch-based films was determined using the CIE Lab scale under different pH conditions and compared with the control. The fabricated (S/BPE and S/BPE/TiO₂) films exhibited visually perceptible colour changes in the pH range between 1 and 12. Consequently these films could be used as intelligent pH indicators for monitoring the freshness of prawn seafood samples. During the storage of prawn food samples for 6 days, the color of the film changed from light pink to green which is a clear indication of spoilage of food material.

Anthocyanin extracted from butterfly pea flower incorporated starch/TiO₂ films are excellent pH indicator for monitoring the freshness of food sample.     

Significance of p53 expression in ovarian tumors and its correlation to the morphological differentiation

Cancer of breast and cervix reign supreme among the fatal diseases in women globally. Interestingly the ovarian cancer has the highest mortality rate. This is attributed to its late clinical presentation and delayed diagnosis. The expression of p53 throws light on the prognosis of ovarian tumors. The surface epithelial tumors, especially the serous cystadenocarcinoma and non Hodgkin lymphoma of ovary where in the expression p53 was high compared to the benign and borderline tumors. Further the expression of p53 in tumors arising from germinal cells, sex-cord stromal cells are observed to be very low. The expression of p53 and its correlation to the morphology enhances the prognostic significance.     

Up-regulation of nucleotide excision repair in mouse lung and liver following chronic exposure to aflatoxin B1 and its dependence on p53 genotype

Aflatoxin B₁ (AFB₁) is biotransformed in vivo into an epoxide metabolite that forms DNA adducts that may induce cancer if not repaired. p53 is a tumor suppressor gene implicated in the regulation of global nucleotide excision repair (NER). Male heterozygous p53 knockout (B6.129-Trp53^tm1BrdN5, Taconic) and wild-type mice were exposed to 0, 0.2 or 1.0 ppm AFB₁ for 26 weeks. NER activity was assessed with an in vitro assay, using AFB₁-epoxide adducted plasmid DNA as a substrate. For wild-type mice, repair of AFB₁–N7-Gua adducts was 124% and 96% greater in lung extracts from mice exposed to 0.2 ppm and 1.0 ppm AFB₁ respectively, and 224% greater in liver extracts from mice exposed to 0.2 ppm AFB₁ (p < 0.05). In heterozygous p53 knockout mice, repair of AFB₁–N7-Gua was only 45% greater in lung extracts from mice exposed to 0.2 ppm AFB₁ (p < 0.05), and no effect was observed in lung extracts from mice treated with 1.0 ppm AFB₁ or in liver extracts from mice treated with either AFB₁ concentration. p53 genotype did not affect basal levels of repair. AFB₁ exposure did not alter repair of AFB₁-derived formamidopyrimidine adducts in lung or liver extracts of either mouse genotype nor did it affect XPA or XPB protein levels. In summary, chronic exposure to AFB₁ increased NER activity in wild-type mice, and this response was diminished in heterozygous p53 knockout mice, indicating that loss of one allele of p53 limits the ability of NER to be up-regulated in response to DNA damage.     

Human spleen cell generation of factors stimulating human pluripotent stem cell, erythroid, and myeloid progenitor cell growth

Mitogen-stimulated murine spleen cells produce humoral substances capable of supporting murine hematopoiesis and pluripotent stem cell proliferation in vitro. Thus, we evaluated conditioned media generated by human spleen cells (SCM) in the presence or absence of mitogens for factors stimulatory for human pluripotent (CFU-GEMM), erythroid (BFU- E), and myeloid (CFU-GM) precursors. Two and one half percent to 10% SCM stimulated proliferation of all three types of precursor cells from nonadherent buoyant human marrow target cells. Mitogen-stimulated SCM augmented CFU-GM (175% to 225%), whereas CFU-GEMM and BFU-E growth was essentially unchanged. Cell separation procedures used to determine which cells provided these microenvironmental stimuli indicated that nonadherent mononuclear spleen cells provided the bulk of the CSF-GM, whereas adherent cells (95% nonspecific esterase + monocyte- macrophages) and nonadherent cells provided similar proportions of CSF- mix and erythroid burst-promoting activity (BPA). The nonadherent cells generating high levels of CSF-mix, BPA, and CSF-GM were predominantly Leu-1-negative, ie, non-T, cells. In the presence or absence of mitogens, SCM was a more potent source (1.3- to 3.8-fold) than peripheral leukocyte CM of the growth factors for the three progenitor cell types. Specific in situ cytochemical stains for analyzing morphology of myeloid colonies demonstrated that SCM stimulated the proliferation of the same types and proportions of colonies as human placental CM, suggesting that these CMs may contain similar CSF-GMs. These data show the contribution of spleen cell subsets to the generation of hematopoietic growth factors and the responsiveness of these cells to various mitogenic stimuli.     

Native associations of early hematopoietic stem cells and stromal cells isolated in bone marrow cell aggregates

In suspensions of murine bone marrow, many stromal cells are tightly entwined with hematopoietic cells. These cellular aggregations appear to exist normally within the marrow. Previous studies showed that lymphocytes and stem cells adhered to stromal cells via vascular cell adhesion molecule 1 (VCAM1). Injection of anti-VCAM1 antibody into mice disrupts the aggregates, showing the importance of VCAM1 in the adhesion between stromal cells and hematopoietic cells in vivo. Early hematopoietic stem cells were shown to be enriched in aggregates by using a limiting-dilution culture assay. Myeloid progenitors responsive to WEHI-3CM in combination with stem cell factor (c-kit ligand) and B220- B-cell progenitors responsive to insulin-like growth factor-1 in combination with interleukin-7 are not enriched. We propose a scheme of stromal cell-hematopoietic cell interactions based on the cell types selectively retained within the aggregates. The existence of these aggregates as native elements of bone marrow organization presents a novel means to study in vivo stem cell-stromal cell interaction.