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Toluidine Blue (toluidine + blue)

Distribution by Scientific Domains

Medical Sciences	38%
Life Sciences	28%
Chemistry	23%
2 Other Domains	11%

Terms modified by Toluidine Blue

toluidine blue staining

Selected Abstracts

Photocatalytic reduction of carbonates and formation of some energy rich systems in the presence of Toluidine Blue

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 2 2001
Sarita Jain
Abstract Aqueous sodium and potassium carbonates have been photoreduced in the presence of Toluidine Blue solution (which is also the photocatalyst). The photocatalytic formation of formic acid and formaldehyde was measured spectrophotometrically using Nash reagent. The effect of variation of various parameters like pH, amount of photocatalyst (Toluidine Blue concentration), concentration of Na2CO3 and K2CO3, light intensity, etc., on the yield of photoproducts was also investigated. A tentative mechanism for this reduction has been proposed. Copyright © 2001 John Wiley & Sons, Ltd. [source]

The effect of toluidine blue on the survival, dormancy and outer membrane porin proteins (OmpC and OmpF) of Salmonella typhimurium LT2 in seawater

JOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2002
R. Ozkanca
Aims: To study the relationship between changes in the composition of the outer membrane proteins and the survival of Salmonella typhimurium LT2 in filtered autoclaved seawater containing Toluidine Blue (TB) dye as a photosensitizer. Methods and Results: In samples exposed to TB and excited by artificial visible light, the total viable (TVC) and respiring cell counts (RCC) showed that, although the TVC declined to an undetectable level in 6·5 h, the RCC showed that some cells were still capable of respiration. The porin protein composition changed gradually with OmpC and OmpF becoming undetectable by sodium dodecyl sulphate-polyacrylamide gel electrophoresis after 8 h of incubation. Hydrogen peroxide-pretreated cells survived longer compared with the control. Conclusions: Oxidative pretreatment of Salm. typhimurium protects cells from some of the effects of sunlight in the presence of photosensitizers. The changes in porin proteins may play a role in this protection. Significance and Impact of the Study: The study shows that the survival of bacteria under conditions of stress is the result of a linked series of reactions. [source]

Soil-borne wheat mosaic virus inclusion bodies: structural, compositional and staining properties

ANNALS OF APPLIED BIOLOGY, Issue 2 2003
L J LITTLEFIELD
Summary Anatomy and cytochemistry of inclusion bodies induced by Soil-borne wheat mosaic virus infection were studied in roots and leaves to learn more about the nature of inclusions and their roles in pathogenesis. Acid Fuchsin, Giemsa stain, Toluidine Blue and Trypan Blue stains facilitated visualization of inclusion bodies. Combined, simultaneous staining with Acid Fuchsin and Toluidine Blue clearly differentiated inclusion bodies from host nuclei. The overall anatomy, composition and structure of virus inclusions in leaves and roots were generally similar, as shown by phase contrast, differential interference contrast, epifluorescence, laser scanning confocal and transmission electron microscopy. Both were often closely associated with host nuclei; both were comprised of intertwined masses of tubular material, presumably endoplasmic reticulum, and in which varied numbers and sizes of vacuolar cavities occurred. Leaf inclusions, however, were typically larger and more vacuolate than those in roots. Lipids were found to be significant constituents of both the tubular and vacuolar components of inclusions, indicated by positive staining with Nile Red and Sudan Black. Inclusion bodies in both leaves and roots lost their structural and compositional integrity, eventually becoming disorganized and devoid of clearly identifiable components as host tissue aged and symptom expression advanced. Significant results of this study include the first published examination of virus inclusion bodies in root tissue, the degree of structural detail of inclusion body anatomy revealed by laser scanning confocal microscopy and the presence of an extensive lipid component in virus inclusion bodies. [source]

Electrocatalytic Reduction of Nitrite Ion on a Toluidine Blue Sol-Gel Thin Film Electrode Derived from 3-Aminopropyl Trimethoxy Silane

ELECTROANALYSIS, Issue 22 2007
K. Thenmozhi
Abstract An organically modified sol-gel electrode using 3-aminopropyltrimethoxy silane for covalent immobilization of a redox mediator namely toluidine blue has been reported. Cyclic voltammetric characterization of the modified electrode in the potential range of 0.2,V to ,0.6,V exhibited stable voltammetric behavior in aqueous supporting electrolyte with a formal potential of ,0.265,V vs. SCE, corresponding to immobilized toluidine blue. The electrocatalytic activity of the modified electrode when tested towards nitrite ion exhibited a favorable response with the electrocatalytic reduction of nitrite occurring at a reduced potential of ,0.34,V. A good linear working range from 2.94×10,6,M to 2.11×10,3,M with a detection limit of 1.76×10,6,M and quantification limit of 5.87×10,6,M was obtained for nitrite determination. The stable and quick response (4,s) of the modified electrode towards nitrite under hydrodynamic conditions shows the feasibility of using the present sensor in flow systems. Significant improvements in the operational stability by overcoming the leachability problem and repeatability with a relative standard deviation of 1.8% of the TB thin film sensor have been obtained by the strategy of immobilization of the mediator in the sol-gel matrix. [source]

Electrocatalysis and Amperometric Detection of the Reduced Form of Nicotinamide Adenine Dinucleotide at Toluidine Blue/Zinc Oxide Coated Electrodes

ELECTROANALYSIS, Issue 18 2007
Ashok Kumar
Abstract Thin toluidine blue (TBO) and zinc oxide (ZnO) hybrid films have been grown on glassy carbon electrode (GCE) and indium tin oxide coated (SnO2) glass electrodes by using cyclic voltammetry (CV). Scanning electron microscopy (SEM) images revealed spherical and beads-like shape of highly oriented TBO/ZnO hybrid films. Energy dispersive spectrometry (EDS) results declared that the films composed mainly of Zn and O. Moreover, TBO/ZnO hybrid films modified electrode is electrochemically active, dye molecules were not easily leached out from the ZnO matrix and the hybrid films can be considered for potential applications as sensor for amperometric determination of reduced nicotinamide adenine dinucleotide (NADH) at 0.0,V. A linear correlation between electrocatalytic current and NADH concentration was found to be in the range between 25,,M and 100,,M in phosphate buffer. In addition, we observed that dopamine, ascorbic acid and uric acid are not interference in amperometric detection of NADH in this proposed method. In addition, TBO/ZnO hybrid film modified electrode was highly stable and its response to the NADH also remained relentless. [source]

Effects of singlet oxygen on membrane sterols in the yeast Saccharomyces cerevisiae

FEBS JOURNAL, Issue 6 2000
Till Böcking
Photodynamic treatment of the yeast Saccharomyces cerevisiae with the singlet oxygen sensitizer toluidine blue and visible light leads to rapid oxidation of ergosterol and accumulation of oxidized ergosterol derivatives in the plasma membrane. The predominant oxidation product accumulated was identified as 5,,6,-epoxy-(22E)-ergosta-8,22-dien-3,,7,-diol (8-DED). 9(11)-dehydroergosterol (DHE) was identified as a minor oxidation product. In heat inactivated cells ergosterol is photooxidized to ergosterol epidioxide (EEP) and DHE. Disrupted cell preparations of S. cerevisiae convert EEP to 8-DED, and this activity is abolished in a boiled control indicating the presence of a membrane associated enzyme with an EEP isomerase activity. Yeast selectively mobilizes ergosterol from the intracellular sterol ester pool to replenish the level of free ergosterol in the plasma membrane during singlet oxygen oxidation. The following reaction pathway is proposed: singlet oxygen-mediated oxidation of ergosterol leads to mainly the formation of EEP, which is enzymatically rearranged to 8-DED. Ergosterol 7-hydroperoxide, a known minor product of the reaction of singlet oxygen with ergosterol, is formed at a much lower rate and decomposes to give DHE. Changes of physical properties of the plasma membrane are induced by depletion of ergosterol and accumulation of polar derivatives. Subsequent permeation of photosensitizer through the plasma membrane into the cell leads to events including impairment of mitochondrial function and cell inactivation. [source]

dye (arc) mutants: insights into an unexplained phenotype and its suppression by the synthesis of poly (3-hydroxybutyrate) in Escherichia coli recombinants

FEMS MICROBIOLOGY LETTERS, Issue 1 2006
Jimena A. Ruiz
Abstract arcA codes for a central regulator in Escherichia coli that responds to redox conditions of growth. Mutations in this gene, originally named dye, confer sensitivity to toluidine blue and other redox dyes. However, the molecular basis for the dye-sensitive phenotype has not been elucidated. In this work, we show that toluidine blue redirects electrons to O2 and causes an increase in the generation of reactive O2 species (ROS). We also demonstrate that synthesis of poly (3-hydroxybutyrate) suppresses the Dye phenotype in E. coli recombinants, as the capacity to synthesize the polymer reduces sensitivity to toluidine blue, O2 consumption and ROS production levels. [source]

The effect of toluidine blue on the survival, dormancy and outer membrane porin proteins (OmpC and OmpF) of Salmonella typhimurium LT2 in seawater

Loss of Osteocyte Integrity in Association with Microdamage and Bone Remodeling After Fatigue In Vivo,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2000
Olivier Verborgt
Abstract As a result of fatigue, bone sustains microdamage, which is then repaired by bone-remodeling processes. How osteoclastic activity is targeted at the removal of microdamaged regions of bone matrix is unknown. In the current studies, we tested the hypothesis that changes in osteocyte integrity, through the initiation of regulated cell death (apoptosis), are associated with fatigue-related microdamage and bone resorption. Ulnae of adult rats were fatigue-loaded to produce a known degree of matrix damage. Osteocyte integrity was then assessed histomorphometrically from terminal deoxynucleotidyl transferase,mediated deoxyuridine triphosphate,nick end labeling (TUNEL),stained sections to detect cells undergoing DNA fragmentation associated with apoptosis; toluidine blue,stained sections were used for secondary morphological confirmation. Ten days after loading, large numbers of TUNEL-positive osteocytes were found in bone surrounding microcracks and in bone surrounding intracortical resorption spaces (,300% increases over controls, p < 0.005). TUNEL labeling in loaded ulnae at sites distant from microcracks or resorption foci did not differ from that in control bone. Osteocytes in toluidine blue,stained sections showed equivalent trends to TUNEL-stained sections, with significant increases in pyknotic nuclei and empty lacunae associated with microcracks and intracortical resorption spaces. TUNEL-positive osteocytes were observed around bone microdamage by 1 day after loading (p < 0.01 relative to baseline), and their number remained elevated throughout the entire experimental period. Increases in empty lacunae and decreases in normal osteocyte numbers were observed over time as well. These studies show that (1) osteocyte apoptosis is induced by bone fatigue, (2) this apoptosis is localized to regions of bone that contain microcracks, and (3) osteoclastic resorption after fatigue also coincides with regions of osteocyte apoptosis. The strong associations between microdamage, osteocyte apoptosis, and subsequent bone remodeling support the hypothesis that osteocyte apoptosis provides a key part of the activation or signaling mechanisms by which osteoclasts target bone for removal after fatigue-induced matrix injury. [source]

Lateral ridge augmentation by the use of grafts comprised of autologous bone or a biomaterial.

JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 12 2002
An experiment in the dog
Abstract Objective: The present investigation was performed to determine if a block of Bio-Oss® used as an onlay graft can be used as a scaffold for new bone formation. Material and methods: Five mongrel dogs were used. The mandibular premolars were extracted. On both sides of the mandible, the buccal bone plate was resected and defects, about 25 mm long, 8 mm high and 5 mm wide, were produced After 3 months of healing, a second surgical procedure was performed. In the left side, a block of Bio-Oss® was adjusted to the buccal bone wall. The graft had the shape of a cylinder and was retained with a miniscrew and covered with a collagen membrane. In the contra-lateral side of the mandible, a block biopsy was first obtained from the ascending ramus. This bone graft had the shape of a cylinder that was 8 mm in diameter and 3 mm thick. The graft was transferred to the experimental site, adjusted to the buccal wall, retained with a miniscrew, and covered with a membrane. The flaps were repositioned and closed with sutures to ensure a complete coverage of the experimental sites. After 6 months of healing, the dogs were sacrificed and the experimental sites dissected. The biopsies were processed for ground sectioning. The sections were stained in toluidine blue, examined in the microscope, and a number of histo- and morphometric assessments made. Results: The study demonstrated that cortical bone used as an onlay graft in the lateral aspect of the alveolar ridge, during a 6-month period of healing integrated with the host bone but underwent marked peripheral resorption. Thus, close to 30% of the height and 50% of the length of the graft was replaced with connective tissue. It was further observed that while the dimensions of a graft which contained a scaffold of cancellous bovine bone mineral remained unchanged, only moderate amounts of new bone formed at the base of this graft. Conclusion: Grafts of autologous cortical bone, placed on the surface of a one-wall defect, may undergo marked resorption during healing. A similar graft of Bio-Oss® may retain its dimension, and limited amounts of new bone will form within the biomaterial. [source]

Mast cell tryptase and microphthalmia transcription factor effectively discriminate cutaneous mast cell disease from myeloid leukemia cutis

JOURNAL OF CUTANEOUS PATHOLOGY, Issue 4 2007
Uma N. Sundram
Background:, Cutaneous mast cell disorders are uncommon, but a subset, especially mastocytoma and mast cell leukemia, can histologically mimic myeloid leukemia cutis. Our objective was to employ a panel of cytochemical and immunohistochemical markers to determine which ones would be most useful in separating these two entities. Methods:, We stained 17 cases of cutaneous mast cell disease and 20 cases of myeloid leukemia cutis with Giemsa, toluidine blue, or pinacyanol erythrosinate (PE), as well as with antibodies against mast cell tryptase, microphthalmia transcription factor (MiTF), CD117 (c-kit), myeloperoxidase, CD43, CD25, CD2, and CD68. Results:, Mast cell tryptase and MiTF emerged as highly sensitive and specific markers for mast cell disease in this context, as both antibodies stained all cases of mast cell diseases but none of myeloid leukemia cutis. Although CD117 stained all cases of mast cell disease, it also stained 2 of 18 cases of myeloid leukemia cutis. PE appeared to be specific for mast cell disease, as 11 of 12 cases stained with this marker, compared with 0 of 18 cases of myeloid leukemia cutis. Conclusions:, Our results show that mast cell tryptase and MiTF are equally effective in distinguishing mast cell disease from myeloid leukemia cutis. [source]

Cytochemical method for staining fish basophils

JOURNAL OF FISH BIOLOGY, Issue 1 2006
M. Tavares-Dias
The occurrence of basophils in peripheral blood of 15 freshwater teleosts was examined using the metachromatic stain, toluidine blue, on blood smears fixed with lead subacetate. Metachromasia was more identifiable through better preservation of the granules. The occurrence of basophils in teleost blood was confirmed as very rare and was not caused by failure to preserve the basophil granules. [source]

A simple protocol for paraffin-embedded myelin sheath staining with osmium tetroxide for light microscope observation

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 7 2008
Federica Di Scipio
Abstract Experimental investigation of peripheral nerve fiber regeneration is attracting more and more attention among both basic and clinical researchers. Assessment of myelinated nerve fiber morphology is a pillar of peripheral nerve regeneration research. The gold standard for light microscopic imaging of myelinated nerve fibers is toluidine blue staining of resin-embedded semithin sections. However, many researchers are unaware that the dark staining of myelin sheaths typically produced by this procedure is due to osmium tetroxide postfixation and not due to toluidine blue. In this article, we describe a simple pre-embedding protocol for staining myelin sheaths in paraffin-embedded nerve specimens using osmium tetroxide. The method involves immersing the specimen in 2% osmium tetroxide for 2 h after paraformaldeyde fixation, followed by routine dehydration and paraffin embedding. Sections can then be observed directly under the microscope or counterstained using routine histological methods. Particularly good results were obtained with Masson's trichrome counterstain, which permits the imaging of connective structures in nerves that are not detectable in toluidine blue-stained resin sections. Finally, we describe a simple protocol for osmium etching of sections, which makes further immunohistochemical analysis possible on the same specimens. Taken together, our results suggest that the protocol described in this article is a valid alternative to the conventional resin embedding-based protocol: it is much cheaper, can be adopted by any histological laboratory, and allows immunohistochemical analysis to be conducted. Microsc. Res. Tech., 2008. © 2008 Wiley-Liss, Inc. [source]

Compatibility of toluidine blue with laser microdissection and saturation labeling DIGE

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 2 2009
Chandra Kirana
Abstract Tissue fixation and staining protocols for laser microdissection are frequently not fully compatible with subsequent proteomic analysis. We compared the effect of three common histological stains (toluidine blue (TB), hemotoxylin, and hematoxylin and eosin (HE)) on tissue visualization, protein recovery, the saturation labeling reaction, and 2-D electrophoresis. TB provided the best visualization of colorectal tumor tissue during laser microdissection (LMD) and had a comparable effect on protein recovery and the saturation labeling reaction with hematoxylin, provided a modified 2-D clean-up protocol was used. Eosin inhibited both protein recovery and the saturation labeling reaction. [source]

The Influence of Pre- and Post-ovulatory Insemination and Early Pregnancy on the Infiltration by Cells of the Immune System in the Sow Oviduct

REPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2006
J Jiwakanon
Contents The aim of this study was to investigate the influence of pre- and post-ovulatory insemination and early pregnancy on the distribution of immune cells in the oviduct. Eighteen sows were pre-ovulatory and sixteen sows were post-ovulatory inseminated and slaughtered at different times, 5,6 h after insemination, 20,25 h and approximately 70 h after ovulation, day 11 and day 19. Immediately after slaughter, oviductal samples of three different segments (isthmus, ampulla and infundibulum) were fixed, embedded in plastic resin and stained with toluidine blue or cryofixed and stored in a freezer at ,70°C until analysed by immunohistochemistry (pre-ovulatory inseminated sows) with an avidin,biotin peroxidase method. Quantitative and qualitative examinations of oviductal epithelium and subepithelial connective tissue were performed by light microscopy. After pre- or post-ovulatory insemination, neutrophils were not observed in the oviductal epithelium from any of the segments or groups. The numbers of intraepithelial lymphocytes of all sows as well as CD2- and CD3-positive cells of the pre-ovulatory inseminated sows were higher in the infundibulum than in the other segments (p , 0.001). In the subepithelial connective tissue of the pre-ovulatory inseminated sows, significantly higher numbers of lymphocytes (p , 0.001) and plasma cells (p , 0.001) were found in infundibulum than in isthmus. Neutrophils were found mainly in infundibulum, the number approximately 40 h after pre-ovulatory insemination was significantly higher (p , 0.05) than in the other groups and segments. Significantly higher numbers of CD2 than CD3-positive cells were found for all groups and segments. In the subepithelial connective tissue of post-ovulatory inseminated sows, the numbers of lymphocytes was higher (p , 0.001) at day 19 than up to 50 h after insemination and lower (p , 0.001) in isthmus than in ampulla and infundibulum. Neutrophils were found in infundibulum in almost all groups and the number was significantly higher (p , 0.05) in the infundibulum up to 50 h after insemination than in other segments. In the oviductal epithelium, no influence of insemination was found on the presence of phagocytes, i.e. neutrophils and macrophages, but on lymphocytes. In the infundibular connective tissue, pre-ovulatory insemination had an effect on neutrophil distribution, indicating an active immune response to insemination in the upper segment. Post-ovulatory insemination changed the oviductal immune cell pattern. [source]

Regional Analysis of the Ependyma of the Third Ventricle of Rat by Light and Electron Microscopy

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2008
T. C. Mathew
Summary Ependymal lining of cerebral ventricles lies at the interface between the ventricular cavities and the brain parenchyma. Ependymal cells are involved in various functions within the brain and play a major role in the production of the chemical principals of the cerebrospinal fluid. Histological studies on the regional variation of the third ventricular ependyma and the subependyma of adult rats were carried out by light and electron microscopic methods. For light microscopic analysis, methacrylate sections were used. In addition to the routine haematoxylin and eosin (H and E) staining for histological studies, the sections were stained with toluidine blue, cresyl violet and periodic acid Schiff's reagent (PAS). A regional analysis of the ependyma of the third ventricle showed that in most regions the ependyma was monolayered. The sidewalls and floor of the ventral portion of the third ventricle showed a multilayered ependyma. For descriptive purposes at the light microscopic level, the ependymal cells were classified, based on the cell shape (flat, cuboidal or columnar), presence or absence of cilia and the number of cytoplasmic granules present in the cells. Studies of transmission electron microscope have shown that these granules represent the cell organelles of the ependyma. The subependyma also showed a regional morphological variation, and, in most instances, contained glial and neuronal elements. In regions of specific brain nuclei, neurons were the major cell type of the subependyma. PAS staining did not show any positive granules in the ependymal cytosol. Characteristic supraependymal elements were present at the ependymal surface of the third ventricle. [source]

Morphological and Immunocytochemical Investigations on Mast Cells in Porcine Ureter

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2005
A. Vodenicharov
Summary Morphological, morphometric, histochemical and immunocytochemical investigations on mast cells, located in the wall of ureter of 8 months aged pigs were performed. Mast cells were found in all three layers of ureteral wall, but their distribution was irregular and the number unequal. It was established that alcian blue (AB)-positive mast cells were significantly more than toluidine blue (TB)-positive mast cells. A statistically significant smaller number of both AB and TB-stained mast cells were observed in the tunica mucosa. The largest number of mast cells was found in the tunica muscularis. In the adventitia, mast cells were higher in number in the main connective tissue than in the connective tissue near the blood vessels. Mast cells stained with TB showed variably expressed , -metachromasia, which was best visible in those situated in the lamina propria of the mucosa. The prevailing parts of mast cells, however, were AB-positive after AB-safranin staining. This was mostly found in mast cells of the tunica muscularis and in mast cells of perivascular location in the tunica adventitia. Immunocytochemically, mast cells were found to be positive for histamine and vasoactive intestinal polypeptide in the muscle coat, and to histamine in the adventitia, as well. On the basis of obtained results it was presumed that the mast cells in porcine ureter most probably took part not only in keeping of local homeostasis, but played also an important role of mobility of smooth muscle cells in the middle layer of ureter on one hand, and, on the other, in the adventitial blood vessels. [source]

Induction of an antiinflammatory effect and prevention of cartilage damage in rat knee osteoarthritis by CF101 treatment

ARTHRITIS & RHEUMATISM, Issue 10 2009
S. Bar-Yehuda
Objective Studies have suggested that rheumatoid arthritis (RA) and osteoarthritis (OA) share common characteristics. The highly selective A3 adenosine receptor agonist CF101 was recently defined as a potent antiinflammatory agent for the treatment of RA. The purpose of this study was to examine the effects of CF101 on the clinical and pathologic manifestations of OA in an experimental animal model. Methods OA was induced in rats by monosodium iodoacetate, and upon disease onset, oral treatment with CF101 (100 ,g/kg given twice daily) was initiated. The A3 adenosine receptor antagonist MRS1220 (100 ,g/kg given twice daily) was administered orally, 30 minutes before CF101 treatment. The OA clinical score was monitored by knee diameter measurements and by radiographic analyses. Histologic analyses were performed following staining with hematoxylin and eosin, Safranin O,fast green, or toluidine blue, and histologic changes were scored according to a modified Mankin system. Signaling proteins were assayed by Western blotting; apoptosis was detected via immunohistochemistry and TUNEL analyses. Results CF101 induced a marked decrease in knee diameter and improved the changes noted on radiographs. Administration of MRS1220 counteracted the effects of CF101. CF101 prevented cartilage damage, osteoclast/osteophyte formation, and bone destruction. In addition, CF101 markedly reduced pannus formation and lymphocyte infiltration. Mechanistically, CF101 induced deregulation of the NF-,B signaling pathway, resulting in down-regulation of tumor necrosis factor ,. Consequently, CF101 induced apoptosis of inflammatory cells that had infiltrated the knee joints; however, it prevented apoptosis of chondrocytes. Conclusion CF101 deregulated the NF-,B signaling pathway involved in the pathogenesis of OA. CF101 induced apoptosis of inflammatory cells and acted as a cartilage protective agent, which suggests that it would be a suitable candidate drug for the treatment of OA. [source]

Cartilage Tissue Engineering With Demineralized Bone Matrix Gelatin and Fibrin Glue Hybrid Scaffold: An In Vitro Study

ARTIFICIAL ORGANS, Issue 2 2010
Zheng-Hui Wang
Abstract To develop a cartilage-like tissue with hybrid scaffolds of demineralized bone matrix gelatin (BMG) and fibrin, rabbit chondrocytes were cultured on hybrid fibrin/BMG scaffolds in vitro. BMG scaffolds were carefully soaked in a chondrocyte,fibrin suspension, which was polymerized by submerging the constructs into thrombin,calcium chloride solution. Engineered cartilage-like tissue grown on the scaffolds was characterized by histology, immunolocalization, scanning electron microscopy, biochemical assays, and analysis of gene expression at different time points of the in vitro culture. The presence of proteoglycan in the fibrin/BMG hybrid constructs was confirmed by positive toluidine blue and alcian blue staining. Collagen type II exhibited intense immunopositivity at the pericellular matrices. Chondrogenic properties were further demonstrated by the expression of gene-encoded cartilage-specific markers, collagen type II, and aggrecan core protein. The glycosaminoglycan production and hydroxyproline content of tissue grown on the fibrin/BMG hybrid scaffolds were higher than that of the BMG group. In conclusion, the fibrin/BMG hybrid scaffolds may serve as a potential cell delivery vehicle and a structural basis for cartilage tissue engineering. [source]

Screening programmes for the early detection and prevention of oral cancer

AUSTRALIAN DENTAL JOURNAL, Issue 2 2009
O Kujan
Background:, Screening programmes for major cancers, such as breast and cervical cancer have effectively decreased the mortality rate and helped to reduce the incidence of these cancers. Although oral cancer is a global health problem with increasing incidence and mortality rates, no national population-based screening programmes for oral cancer have been implemented. To date there is debate on whether to employ screening methods for oral cancer in the daily routine work of health providers. Objectives:, To assess the effectiveness of current screening methods in decreasing oral cancer mortality. Search strategy:, Electronic databases (MEDLINE, CANCERLIT, EMBASE (1966 to July 2005) and CENTRAL (The Cochrane Library 2005, Issue 3), bibliographies, handsearching of specific journals and contact authors were used to identify published and unpublished data. Selection criteria:, Randomized controlled trials of screening for oral cancer or precursor oral lesions using visual examination, toluidine blue, fluorescence imaging or brush biopsy. Data collection and analysis:, The search found 112 citations and these have been reviewed. One randomized controlled trial of screening strategies for oral cancer was identified as meeting the review's inclusion criteria. Validity assessment, data extraction and statistics evaluation were undertaken by two independent review authors. Main results:, One 10-year randomized controlled trial has been included (n = 13 clusters: 191 873 participants). There was no difference in the age-standardized oral cancer mortality rates for the screened group (16.4/100 000 person-years) and the control group (20.7/100 000 person-years). Interestingly, a significant 34% reduction in mortality was recorded in high-risk subjects between the intervention cohort (29.9/100 000 person-years) and the control arm (45.4/100 000). However, this study has some methodological weaknesses. Additionally, the study did not provide any information related to costs, quality of life or even harms of screening from false-positive or false-negative findings. Authors' conclusions:, Given the limitation of evidence (only one included randomized controlled trial) and the potential methodological weakness of the included study, it is valid to say that there is insufficient evidence to support or refute the use of a visual examination as a method of screening for oral cancer using a visual examination in the general population. Furthermore, no robust evidence exists to suggest that other methods of screening, toluidine blue, fluorescence imaging or brush biopsy, are either beneficial or harmful. Future high quality studies to assess the efficacy, effectiveness and costs of screening are required for the best use of public health resources. In addition, studies to elucidate the natural history of oral cancer, prevention methods and the effectiveness of opportunistic screening in high risk groups are needed. Future studies on improved treatment modalities for oral cancer and precancer are also required. Plain language summary:, Screening programmes for the early detection and prevention of oral cancer. More evidence needed to find out whether screening programmes could detect oral cancer earlier and reduce the number of deaths from this disease. Cancer of the mouth and back of the throat (oral cancer) has a low survival rate, largely because the disease is often not diagnosed until it is advanced. Screening the general population for oral cancer might make it possible to detect cases of the disease earlier. The most common method is visual inspection by a clinician, but other techniques include the use of a special blue "dye" and an imaging technique. The review found that there is not enough evidence to decide whether screening by visual inspection reduces the death rate for oral cancer, and no evidence for other screening methods. [source]