Search results for "preservation"
showing 10 items of 484 documents
The role of angiogenesis in implant dentistry part II: the effect of bone-grafting and barrier membrane materials on angiogenesis
2016
Background : In implant dentistry, bone substitute materials and barrier membranes are used in different treatments including guided bone regeneration (GBR), socket preservation, alveolar ridge augmentation, maxillary sinus elevation, and filling bony defects around the inserted dental implant. One of the most important factors in prognosis of treatments using these materials is the growth of new blood vessels in applied areas. Present review was performed to evaluate the effect of the bone-grafting and barrier membrane materials on angiogenesis events. Material and Methods : An electronic search was performed in PubMed, MEDLINE, and EMBASE databases via OVID using the keywords mentioned in…
The use of Human Allogenic Graft (HBA) for Maxillary Bone Regeneration: Review of Literature and Case Reports
2012
The use of graft materials is developed from the strong demand to support the complete bone regeneration of the empty socket and to increase the bone volume in treating the atrophies of sites already consolidated and with adverse alveolar bone conditions. A number of graft materials with different origin and mechanism of bone regeneration are available. Autologous graft materials, coming from the same patient, are defined as the gold-standard. The need of a second surgical site and the risk of morbidity and complications may make their use difficult. Human bone allografts (HBA) have been recently introduced, in order to offer an alternative to the autologous grafts. They have demonstrated t…
Lyophilization of lepidopteran midguts: a preserving method for Bacillus thuringiensis toxin binding studies
2004
Binding assays with brush border membrane vesicles (BBMV) from insect midguts are commonly used in the study of the interactions between Bacillus thuringiensis Cry toxins and their receptors. Collaboration between laboratories often require that frozen insect samples are sent in dry ice. Because of customs restrictions and delays, sample thawing is always a risk and often the biological material becomes ruined during shipping. We have tested lyophilization as an alternative method for preserving insect midguts for binding studies with B. thuringiensis Cry toxins. For this purpose, BBMV were prepared from both frozen and lyophilized midguts from three lepidopteran species: Spodoptera exigua,…
Use of a logistic model to assess spoilage by Byssochlamys fulva in clarified apple juice
2010
Abstract The percentage P (%) of spoiled bottles (n = 40) of clarified apple juice due to Byssochlamys fulva, was modeled by using a logistic model: P = P max 1 + exp ( k ( τ − t ) ) where Pmax (%) the maximum percentage of spoiled bottles, k (h− 1) a slope parameter and τ (h) the time for P = Pmax/2. Bottles of pasteurized apple juice were inoculated with B. fulva IOC 4518 ascospores for low and high initial loads, 4.8 ± 2.3 ascospores/100 mL and 19.3 ± 4.6 ascospores/100 mL respectively and incubated at 21 °C and 30 °C. Pmax was not significantly different from 100% except for a low initial load at 21 °C. Model parameters were estimated with a good accuracy, RMSE in the range 3.89–7.50. T…
Why do results conflict regarding the prognostic value of the methylation status in colon cancers? The role of the preservation method.
2012
Abstract Background In colorectal carcinoma, extensive gene promoter hypermethylation is called the CpG island methylator phenotype (CIMP). Explaining why studies on CIMP and survival yield conflicting results is essential. Most experiments to measure DNA methylation rely on the sodium bisulfite conversion of unmethylated cytosines into uracils. No study has evaluated the performance of bisulfite conversion and methylation levels from matched cryo-preserved and Formalin-Fixed Paraffin Embedded (FFPE) samples using pyrosequencing. Methods Couples of matched cryo-preserved and FFPE samples from 40 colon adenocarcinomas were analyzed. Rates of bisulfite conversion and levels of methylation of …
Survey of Fertility Preservation Options Available to Patients With Cancer Around the Globe
2020
Purpose Oncofertility focuses on providing fertility and endocrine-sparing options to patients who undergo life-preserving but gonadotoxic cancer treatment. The resources needed to meet patient demand often are fragmented along disciplinary lines. We quantify assets and gaps in oncofertility care on a global scale. Methods Survey-based questionnaires were provided to 191 members of the Oncofertility Consortium Global Partners Network, a National Institutes of Health–funded organization. Responses were analyzed to measure trends and regional subtleties about patient oncofertility experiences and to analyze barriers to care at sites that provide oncofertility services. Results Sixty-three res…
Survey of third-party parenting options associated with fertility preservation available to patients with cancer around the globe
2018
Purpose In the accompanying article, “Survey of Fertility Preservation Options Available to Patients With Cancer Around the Globe,” we showed that specific fertility preservation services may not be offered at various sites around the world because of cultural and legal barriers. We assessed global and regional experiences as well as the legal status of third-party reproduction and adoption to serve as a comprehensive international data set and resource for groups that wish to begin oncofertility interventions. Methods We provide data on the legalities of third-party assisted reproductive technologies and other family-building options in the 28 oncofertility-practicing countries surveyed. R…
Cryopreservation of Escherichia coli K12TG1: Protection from the damaging effects of supercooling by freezing
2015
Injuries in living cells caused by water freezing during a freeze-thaw process have been extensively reported. In particular, intracellular water freezing has long been incriminated in cell death caused by a high cooling rate, but this supposition could not always be demonstrated. This work aims to discriminate the role of water freezing, dehydration and cold-induced injuries in cellular damage occuring during cryopreservation. For this purpose, Escherichia coli K12TG1 suspensions were maintained in a supercooled or frozen state at -20°C for times ranging from 10 min to 5 h. The supercooled state was maintained for a long period at -20°C by applying a non-injurious isostatic pressure (P<40 …
Present status of the application of cryopreserved hepatocytes in the evaluation of xenobiotics: consensus of an international expert panel.
1999
Successful cryopreservation of freshly isolated hepatocytes would significantly decrease the need for freshly-procured livers for the preparation of hepatocytes for experimentation. Hepatocytes can be prepared, cryopreserved, and used for experimentation as needed at different times after isolation. Cryopreservation is especially important for research with human hepatocytes because of the limited availability of fresh human livers. Based on the cumulative experience of this international expert panel, a consensus was reached on the various aspects of hepatocyte cryopreservation, including cryopreservation and thawingprocedures and applications of the cryopreserved hepatocytes. Key to succe…