scholarly journals Cryopreservation Methods and Frontiers in the Art of Freezing Life in Animal Models

2022 ◽  
Author(s):  
Feda S. Aljaser
Keyword(s):  
Animal Models ◽  
Slow Rate ◽  
Animal Species ◽  
Freezing Point ◽  
Genetically Engineered ◽  
Cryoprotective Agents ◽  
Animal Diversity ◽  
High Concentrations ◽  
Large Animals ◽  
Genetically Modified Animals

The development in cryobiology in animal breeding had revolutionized the field of reproductive medicine. The main objective to preserve animal germplasm stems from variety of reasons such as conservation of endangered animal species, animal diversity, and an increased demand of animal models and/or genetically modified animals for research involving animal and human diseases. Cryopreservation has emerged as promising technique for fertility preservation and assisted reproduction techniques (ART) for production of animal breeds and genetically engineered animal species for research. Slow rate freezing and rapid freezing/vitrification are the two main methods of cryopreservation. Slow freezing is characterized by the phase transition (liquid turning into solid) when reducing the temperature below freezing point. Vitrification, on the other hand, is a phenomenon in which liquid solidifies without the formation of ice crystals, thus the process is referred to as a glass transition or ice-free cryopreservation. The vitrification protocol applies high concentrations of cryoprotective agents (CPA) used to avoid cryoinjury. This chapter provides a brief overview of fundamentals of cryopreservation and established methods adopted in cryopreservation. Strategies involved in cryopreserving germ cells (sperm and egg freezing) are included in this chapter. Last section describes the frontiers and advancement of cryopreservation in some of the important animal models like rodents (mouse and rats) and in few large animals (sheep, cow etc).

scholarly journals Comparison of Genetically Engineered Immunodeficient Animal Models for Nonclinical Testing of Stem Cell Therapies

Pharmaceutics ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 130
Author(s):  
Yoon-Young Kim ◽  
Jin-Soo Kim ◽  
Jeong-Hwan Che ◽  
Seung-Yup Ku ◽  
Byeong-Cheol Kang ◽  
...  
Keyword(s):  
Stem Cell ◽  
Animal Models ◽  
Stem Cell Research ◽  
Target Genes ◽  
Mutant Gene ◽  
Genetically Engineered ◽  
Model Systems ◽  
Gene Effects ◽  
Cell Therapies ◽  
Large Animals

For the recovery or replacement of dysfunctional cells and tissue—the goal of stem cell research—successful engraftment of transplanted cells and tissues are essential events. The event is largely dependent on the immune rejection of the recipient; therefore, the immunogenic evaluation of candidate cells or tissues in immunodeficient animals is important. Understanding the immunodeficient system can provide insights into the generation and use of immunodeficient animal models, presenting a unique system to explore the capabilities of the innate immune system. In this review, we summarize various immunodeficient animal model systems with different target genes as valuable tools for biomedical research. There have been numerous immunodeficient models developed by different gene defects, resulting in many different features in phenotype. More important, mice, rats, and other large animals exhibit very different immunological and physiological features in tissue and organs, including genetic background and a representation of human disease conditions. Therefore, the findings from this review may guide researchers to select the most appropriate immunodeficient strain, target gene, and animal species based on the research type, mutant gene effects, and similarity to human immunological features for stem cell research.

scholarly journals Engineering of Streptoalloteichus tenebrarius 2444 for Sustainable Production of Tobramycin

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4343
Author(s):  
Lena Mitousis ◽  
Hannes Maier ◽  
Luka Martinovic ◽  
Andreas Kulik ◽  
Sigrid Stockert ◽  
...  
Keyword(s):  
Aminoglycoside Antibiotic ◽  
Biosynthetic Gene Cluster ◽  
Genetically Engineered ◽  
Sustainable Production ◽  
Biosynthetic Gene ◽  
Strain Development ◽  
Antibiotic Agent ◽  
Phenotypic Stability ◽  
High Concentrations ◽  
Hydrolysis Of

Tobramycin is a broad-spectrum aminoglycoside antibiotic agent. The compound is obtained from the base-catalyzed hydrolysis of carbamoyltobramycin (CTB), which is naturally produced by the actinomycete Streptoalloteichus tenebrarius. However, the strain uses the same precursors to synthesize several structurally related aminoglycosides. Consequently, the production yields of tobramycin are low, and the compound’s purification is very challenging, costly, and time-consuming. In this study, the production of the main undesired product, apramycin, in the industrial isolate Streptoalloteichus tenebrarius 2444 was decreased by applying the fermentation media M10 and M11, which contained high concentrations of starch and dextrin. Furthermore, the strain was genetically engineered by the inactivation of the aprK gene (∆aprK), resulting in the abolishment of apramycin biosynthesis. In the next step of strain development, an additional copy of the tobramycin biosynthetic gene cluster (BGC) was introduced into the ∆aprK mutant. Fermentation by the engineered strain (∆aprK_1-17L) in M11 medium resulted in a 3- to 4-fold higher production than fermentation by the precursor strain (∆aprK). The phenotypic stability of the mutant without selection pressure was validated. The use of the engineered S. tenebrarius 2444 facilitates a step-saving, efficient, and, thus, more sustainable production of the valuable compound tobramycin on an industrial scale.

scholarly journals Animal Models of Colorectal Cancer: From Spontaneous to Genetically Engineered Models and Their Applications

2021 ◽  
Vol 8 (4) ◽  
pp. 59
Author(s):  
Elisabete Nascimento-Gonçalves ◽  
Bruno A.L. Mendes ◽  
Rita Silva-Reis ◽  
Ana I. Faustino-Rocha ◽  
Adelina Gama ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Animal Models ◽  
Cancer Progression ◽  
Social Impact ◽  
Genetically Engineered ◽  
In Vivo Studies ◽  
Gastrointestinal Malignancies ◽  
Advantages And Disadvantages ◽  
Colon Cancer Progression

Colorectal cancer is one of the most common gastrointestinal malignancies in humans, affecting approximately 1.8 million people worldwide. This disease has a major social impact and high treatment costs. Animal models allow us to understand and follow the colon cancer progression; thus, in vivo studies are essential to improve and discover new ways of prevention and treatment. Dietary natural products have been under investigation for better and natural prevention, envisioning to show their potential. This manuscript intends to provide the readers a review of rodent colorectal cancer models available in the literature, highlighting their advantages and disadvantages, as well as their potential in the evaluation of several drugs and natural compounds’ effects on colorectal cancer.

scholarly journals Review: Tissue Engineering of Small-Diameter Vascular Grafts and Their In Vivo Evaluation in Large Animals and Humans

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 713
Author(s):  
Shu Fang ◽  
Ditte Gry Ellman ◽  
Ditte Caroline Andersen
Keyword(s):  
Animal Models ◽  
Vascular Grafts ◽  
Small Diameter ◽  
Large Animal ◽  
Large Animal Models ◽  
Graft Outcome ◽  
Limited Success ◽  
Large Animals

To date, a wide range of materials, from synthetic to natural or a mixture of these, has been explored, modified, and examined as small-diameter tissue-engineered vascular grafts (SD-TEVGs) for tissue regeneration either in vitro or in vivo. However, very limited success has been achieved due to mechanical failure, thrombogenicity or intimal hyperplasia, and improvements of the SD-TEVG design are thus required. Here, in vivo studies investigating novel and relative long (10 times of the inner diameter) SD-TEVGs in large animal models and humans are identified and discussed, with emphasis on graft outcome based on model- and graft-related conditions. Only a few types of synthetic polymer-based SD-TEVGs have been evaluated in large-animal models and reflect limited success. However, some polymers, such as polycaprolactone (PCL), show favorable biocompatibility and potential to be further modified and improved in the form of hybrid grafts. Natural polymer- and cell-secreted extracellular matrix (ECM)-based SD-TEVGs tested in large animals still fail due to a weak strength or thrombogenicity. Similarly, native ECM-based SD-TEVGs and in-vitro-developed hybrid SD-TEVGs that contain xenogeneic molecules or matrix seem related to a harmful graft outcome. In contrast, allogeneic native ECM-based SD-TEVGs, in-vitro-developed hybrid SD-TEVGs with allogeneic banked human cells or isolated autologous stem cells, and in-body tissue architecture (IBTA)-based SD-TEVGs seem to be promising for the future, since they are suitable in dimension, mechanical strength, biocompatibility, and availability.

scholarly journals Laboratory Animal Models for Brucellosis Research

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Teane M. A. Silva ◽  
Erica A. Costa ◽  
Tatiane A. Paixão ◽  
Renée M. Tsolis ◽  
Renato L. Santos
Keyword(s):  
Animal Models ◽  
Chronic Infection ◽  
Laboratory Animal ◽  
Animal Species ◽  
Human Brucellosis ◽  
Intracellular Pathogen ◽  
Gram Negative ◽  
Culture Cells ◽  
Pathogenic Factors ◽  
The World

Brucellosis is a chronic infectious disease caused byBrucellaspp., a Gram-negative facultative intracellular pathogen that affects humans and animals, leading to significant impact on public health and animal industry. Human brucellosis is considered the most prevalent bacterial zoonosis in the world and is characterized by fever, weight loss, depression, hepato/splenomegaly, osteoarticular, and genital infections. Relevant aspects ofBrucellapathogenesis have been intensively investigated in culture cells and animal models. The mouse is the animal model more commonly used to study chronic infection caused byBrucella. This model is most frequently used to investigate specific pathogenic factors ofBrucellaspp., to characterize the host immune response, and to evaluate therapeutics and vaccines. Other animal species have been used as models for brucellosis including rats, guinea pigs, and monkeys. This paper discusses the murine and other laboratory animal models for human and animal brucellosis.

scholarly journals The faint young Sun problem revisited with a 3-D climate–carbon model – Part 1

2014 ◽  
Vol 10 (2) ◽  
pp. 697-713 ◽  
Author(s):  
G. Le Hir ◽  
Y. Teitler ◽  
F. Fluteau ◽  
Y. Donnadieu ◽  
P. Philippot
Keyword(s):  
Radiative Forcing ◽  
General Circulation ◽  
Freezing Point ◽  
Climatic Factors ◽  
General Circulation Models ◽  
Companion Paper ◽  
One Dimensional ◽  
Carbon Dioxide Concentrations ◽  
Wide Range ◽  
High Concentrations

Abstract. During the Archaean, the Sun's luminosity was 18 to 25% lower than the present day. One-dimensional radiative convective models (RCM) generally infer that high concentrations of greenhouse gases (CO2, CH4) are required to prevent the early Earth's surface temperature from dropping below the freezing point of liquid water and satisfying the faint young Sun paradox (FYSP, an Earth temperature at least as warm as today). Using a one-dimensional (1-D) model, it was proposed in 2010 that the association of a reduced albedo and less reflective clouds may have been responsible for the maintenance of a warm climate during the Archaean without requiring high concentrations of atmospheric CO2 (pCO2). More recently, 3-D climate simulations have been performed using atmospheric general circulation models (AGCM) and Earth system models of intermediate complexity (EMIC). These studies were able to solve the FYSP through a large range of carbon dioxide concentrations, from 0.6 bar with an EMIC to several millibars with AGCMs. To better understand this wide range in pCO2, we investigated the early Earth climate using an atmospheric GCM coupled to a slab ocean. Our simulations include the ice-albedo feedback and specific Archaean climatic factors such as a faster Earth rotation rate, high atmospheric concentrations of CO2 and/or CH4, a reduced continental surface, a saltier ocean, and different cloudiness. We estimated full glaciation thresholds for the early Archaean and quantified positive radiative forcing required to solve the FYSP. We also demonstrated why RCM and EMIC tend to overestimate greenhouse gas concentrations required to avoid full glaciations or solve the FYSP. Carbon cycle–climate interplays and conditions for sustaining pCO2 will be discussed in a companion paper.

Alzheimer%#x2019;s Disease and Genetically Engineered Animal Models

1999 ◽  
pp. 187-214
Author(s):  
David R. Borchelt ◽  
Philip C. Wong ◽  
Sangram S. Sisodia ◽  
Donald L. Price
Keyword(s):  
Animal Models ◽  
Genetically Engineered

scholarly journals Large Animal Models of Vascularized Composite Allotransplantation: A Review of Immune Strategies to Improve Allograft Outcomes

2021 ◽  
Vol 12 ◽  
Author(s):  
Abraham J. Matar ◽  
Rebecca L. Crepeau ◽  
Gerhard S. Mundinger ◽  
Curtis L. Cetrulo ◽  
Radbeh Torabi
Keyword(s):  
Animal Models ◽  
Ex Vivo ◽  
Solid Organ Transplantation ◽  
Tolerance Induction ◽  
Large Animal ◽  
Solid Organ ◽  
Large Animal Models ◽  
Large Animals ◽  
And Function ◽  
Made In

Over the past twenty years, significant technical strides have been made in the area of vascularized composite tissue allotransplantation (VCA). As in solid organ transplantation, the allogeneic immune response remains a significant barrier to long-term VCA survival and function. Strategies to overcome acute and chronic rejection, minimize immunosuppression and prolong VCA survival have important clinical implications. Historically, large animals have provided a valuable model for testing the clinical translatability of immune modulating approaches in transplantation, including tolerance induction, co-stimulation blockade, cellular therapies, and ex vivo perfusion. Recently, significant advancements have been made in these arenas utilizing large animal VCA models. In this comprehensive review, we highlight recent immune strategies undertaken to improve VCA outcomes with a focus on relevant preclinical large animal models.

scholarly journals Enhancing the Lubricity of Gas-to-Liquid (GTL) Paraffinic Kerosene: Impact of the Additives on the Physicochemical Properties

2020 ◽  
Author(s):  
Hani Ababnah ◽  
Nasr Mohamed ◽  
Hanif Choudhury ◽  
Lei Lei Zhang ◽  
Rafiqul Gani ◽  
...  
Keyword(s):  
Linoleic Acid ◽  
Physicochemical Properties ◽  
Negative Impact ◽  
Freezing Point ◽  
Ethyl Oleate ◽  
Heat Content ◽  
Wear Scar Diameter ◽  
Dual Nature ◽  
Fuel Jet ◽  
High Concentrations

Abstract Synthetic paraffinic kerosene (SPK) is an ultra-clean fuel with low aromatic content and negligible quantities of sulfur compounds . Although, SPK has a good potential to replace the conventional fuel Jet A-1 , it also has some deficiencies. One of them is the low lubricity compared to its conventional counterpart Jet A-1. To improve the lubricity of SPK, three selected additives have been mixed with SPK at different concentrations. The lubricity of the samples was determined experimentally and the samples that meet the industry specifications have been studied further. The effect of the additives on the physicochemical properties, such as, density, flash point, freezing point, viscosity, and heat content, were investigated. Linoleic acid was found to be an excellent lubricity improver even at a very low concentration and its negative impact on the other physicochemical properties was found to be insignificant. Ethyl oleate also demonstrated significant improvement in lubricity at low concentrations but had a negative impact on the fuel’s freezing point at high concentrations. Quinoline, at high concentrations, elevated the blend’s freezing point above the acceptable limits. In parallel to the experimental campaign, a pre-existing mathematical modelling tool was utilized to predict the properties of interest. The lubricity model was successfully introduced into the mathematical model in order to improve the capabilities of the model. Linoleic acid sample showed the best improvement in lubricity of SPK with wear scar diameter of 4 17 μm; well below the ASTM D7566 maximum limit of 850µm. The dual nature of this study facilitated the optimization of the physicochemical properties of the fuel samples.

Vitrification Solutions for the Cryopreservation of Tissue-Engineered Bone

2002 ◽  
Author(s):  
B. L. Liu ◽  
J. J. McGrath
Keyword(s):  
Bending Strength ◽  
Cell Damage ◽  
Mechanical Damage ◽  
Bone Substitutes ◽  
State University ◽  
Scanning Calorimetry ◽  
Destructive Effect ◽  
Cryoprotective Agents ◽  
Liquid Suspension ◽  
High Concentrations

Osteoblast (OB)-seeded hydroxyapatite (HA) scaffold cortical bone substitutes are being developed at Michigan State University. Preservation methods need to be developed to preserve such living products to ensure a steady supply for transplantation. Theoretically vitrification is an attractive method for the cryopreservation of tissue-engineered bone because it can eliminate the destructive effect of ice formation [1]. However, relatively fast cooling and warming rates are required to avoid damage associated with ice crystallization and relatively high concentrations of cryoprotective agents (CPAs) are required to achieve a glassy (vitrified) state. These rapid rates of temperature change may not be possible as tissue-engineered structures become larger. In addition to cell damage, rapid rates may also cause destructive thermo mechanical damage to the scaffold itself. Slower rates can be used to achieve the vitrified state but this requires higher CPA concentrations, which are more toxic. As a means of studying the interactive determinants of an optimal vitrification process for osteoblasts, we have undertaken thermal analysis of a variety of vitrification solutions of interest using differential scanning calorimetry (DSC) to determine the critical cooling and warming rates. The toxicity dynamics and tendency for the scaffolds to be damaged mechanically by the vitrification process are also examined. Glycerol and dimethyl sulfoxide at a concentration of 40% were studied with and without an ice blocker. Two vitrification “cocktails” (VS55 and VEG) over a concentration range of 80% to 100% were studied with and without an ice blocker. On the basis of these studies 95% VEG with ice blocker was least toxic and yielded the highest recovery (∼90%) for OBs vitrified in liquid suspension. Vitrification does not seem to be detrimental to the bending strength of high density (low porosity) HA scaffolds, but lower density HA scaffolds break more easily after vitrification in some instances.

Sign in / Sign up

Export Citation Format

Share Document