scholarly journals THE RELATIVE EXTENSIBILITY OF CELL SURFACES

1963 ◽  
Vol 17 (2) ◽  
pp. 289-297 ◽  
Author(s):  
Murray D. Rosenberg
Keyword(s):  
Cell Culture ◽  
Mechanical Deformation ◽  
Culture Chamber ◽  
Cell Surfaces ◽  
Statistical Index ◽  
Degree Of Deformation ◽  
Large Numbers ◽  
Dissociated Cells ◽  
Definition Of

Observations have been made on the response, in vitro, of cultured and freshly dissociated cells to mechanical deformation. Large numbers of individual cells were studied by means of a special culture chamber bounded by two parallel glass coverslips whose spacing could be reduced from 140 to 2 microns in steps of roughly 0.5 micron. The degree of deformation required for herniation of the cell surface was measured. These measurements lead to the definition of a statistical index characteristic of the extensibility of cell surfaces. This index has been shown to be distinctive for several types of cells; to alter with certain stages of embryonic development; and to be stable with respect to the culturing of cells and certain alterations in the method of cell culture.

scholarly journals Designing Hydrogel-Based Bone-On-Chips for Personalized Medicine

2021 ◽  
Vol 11 (10) ◽  
pp. 4495
Author(s):  
Gabriele Nasello ◽  
Mar Cóndor ◽  
Ted Vaughan ◽  
Jessica Schiavi
Keyword(s):  
Three Dimensional ◽  
In Vitro Models ◽  
Patient Specific ◽  
Specific Situation ◽  
Culture Chamber ◽  
Definition Of ◽  
And Function ◽  
Tissue Matrix ◽  
Hematopoietic Niche

The recent development of bone-on-chips (BOCs) holds the main advantage of requiring a low quantity of cells and material, compared to traditional In Vitro models. By incorporating hydrogels within BOCs, the culture system moved to a three dimensional culture environment for cells which is more representative of bone tissue matrix and function. The fundamental components of hydrogel-based BOCs, namely the cellular sources, the hydrogel and the culture chamber, have been tuned to mimic the hematopoietic niche in the bone aspirate marrow, cancer bone metastasis and osteo/chondrogenic differentiation. In this review, we examine the entire process of developing hydrogel-based BOCs to model In Vitro a patient specific situation. First, we provide bone biological understanding for BOCs design and then how hydrogel structural and mechanical properties can be tuned to meet those requirements. This is followed by a review on hydrogel-based BOCs, developed in the last 10 years, in terms of culture chamber design, hydrogel and cell source used. Finally, we provide guidelines for the definition of personalized pathological and physiological bone microenvironments. This review covers the information on bone, hydrogel and BOC that are required to develop personalized therapies for bone disease, by recreating clinically relevant scenarii in miniaturized devices.

scholarly journals Genomic positional conservation identifies topological anchor point (tap)RNAs linked to developmental loci

2016 ◽  
Author(s):  
Paulo P. Amaral ◽  
Tommaso Leonardi ◽  
Namshik Han ◽  
Emmanuelle Viré ◽  
Dennis K. Gascoigne ◽  
...  
Keyword(s):  
Noncoding Rnas ◽  
Conserved Sequence ◽  
Positional Conservation ◽  
Large Numbers ◽  
Human Genomes ◽  
Mammalian Genomes ◽  
Recognition Motifs ◽  
Definition Of

The mammalian genome is transcribed into large numbers of long noncoding RNAs (lncRNAs), but the definition of functional lncRNA groups has proven difficult, partly due to their low sequence conservation and lack of identified shared properties. Here we consider positional conservation across mammalian genomes as an indicator of functional commonality. We identify 665 conserved lncRNA promoters in mouse and human genomes that are preserved in genomic position relative to orthologous coding genes. The identified ‘positionally conserved’ lncRNA genes are primarily associated with developmental transcription factor loci with which they are co-expressed in a tissue-specific manner. Strikingly, over half of all positionally conserved RNAs in this set are linked to distinct chromatin organization structures, overlapping the binding sites for the CTCF chromatin organizer and located at chromatin loop anchor points and borders of topologically associating domains (TADs). These topological anchor point (tap)RNAs possess conserved sequence domains that are enriched in potential recognition motifs for Zinc Finger proteins. Characterization of these noncoding RNAs and their associated coding genes shows that they are functionally connected: they regulate each other’s expression and influence the metastatic phenotype of cancer cells in vitro in a similar fashion. Thus, interrogation of positionally conserved lncRNAs identifies a new subset of tapRNAs with shared functional properties. These results provide a large dataset of lncRNAs that conform to the “extended gene” model, in which conserved developmental genes are genomically and functionally linked to regulatory lncRNA loci across mammalian evolution.

scholarly journals Detection of Infectious Cryptosporidium Oocysts by Cell Culture Immunofluorescence Assay: Applicability to Environmental Samples

2005 ◽  
Vol 71 (11) ◽  
pp. 6793-6798 ◽  
Author(s):  
F. M. Schets ◽  
G. B. Engels ◽  
M. During ◽  
A. M. de Roda Husman
Keyword(s):  
Cell Culture ◽  
Water Samples ◽  
Environmental Samples ◽  
Immunofluorescence Assay ◽  
Risk Of Infection ◽  
Large Numbers ◽  
High Level ◽  
Different Sources

ABSTRACT In the past few years many waterborne outbreaks related to Cryptosporidium have been described. Current methods for detection of Cryptosporidium in water for the most part rely on viability assays which are not informative concerning the infectivity of oocysts. However, for estimation of the risk of infection with Cryptosporidium this information is required. For environmental samples the oocyst counts are often low, and the oocysts have been exposed to unfavorable conditions. Therefore, determination of the infectivity of environmental oocysts requires an assay with a high level of sensitivity. We evaluated the applicability of in vitro cell culture immunofluorescence assays with HCT-8 and Caco-2 cells for determination of oocyst infectivity in naturally contaminated water samples. Cell culture assays were compared with other viability and infectivity assays. Experiments with Cryptosporidium oocysts from different sources revealed that there was considerable variability in infectivity, which was illustrated by variable 50% infective doses, which ranged from 40 to 614 oocysts, and the results indicated that not only relatively large numbers of fresh oocysts but also aged oocysts produced infection in cell cultures. Fifteen Dutch surface water samples were tested, and the cell culture immunofluorescence assays were not capable of determining the infectivity for the low numbers of naturally occurring Cryptosporidium oocysts present in the samples. A comparison with other viability assays, such as the vital dye exclusion assay, demonstrated that surrogate methods overestimate the number of infectious oocysts and therefore the risk of infection with Cryptosporidium. For accurate risk assessment, further improvement of the method for detection of Cryptosporidium in water is needed.

Cytoplasmic Granules in Lymphocytes from Rats Dosed with SK&F 14336-D

1971 ◽  
Vol 29 ◽  
pp. 556-557
Author(s):  
T. G. Merrill ◽  
B. J. Payne ◽  
A. J. Tousimis
Keyword(s):  
Lipid Storage ◽  
Pokeweed Mitogen ◽  
Electron Microscopic ◽  
Cytoplasmic Granules ◽  
Storage Diseases ◽  
Tay Sachs Disease ◽  
Large Numbers ◽  
Microscopic Studies ◽  
Neurovisceral Lipidosis

Rats given SK&F 14336-D (9-[3-Dimethylamino propyl]-2-chloroacridane), a tranquilizing drug, developed an increased number of vacuolated lymphocytes as observed by light microscopy. Vacuoles in peripheral blood of rats and humans apparently are rare and are not usually reported in differential counts. Transforming agents such as phytohemagglutinin and pokeweed mitogen induce similar vacuoles in in vitro cultures of lymphocytes. These vacuoles have also been reported in some of the lipid-storage diseases of humans such as amaurotic familial idiocy, familial neurovisceral lipidosis, lipomucopolysaccharidosis and sphingomyelinosis. Electron microscopic studies of Tay-Sachs' disease and of chloroquine treated swine have demonstrated large numbers of “membranous cytoplasmic granules” in the cytoplasm of neurons, in addition to lymphocytes. The present study was undertaken with the purpose of characterizing the membranous inclusions and developing an experimental animal model which may be used for the study of lipid storage diseases.

1120: Citrate and Vitamin E Blunt the SWL-Induced Free Radical Surge in an In-Vitro MDCK Cell Culture Model

2004 ◽  
Vol 171 (4S) ◽  
pp. 295-295
Author(s):  
Fernando C. Delvecchio ◽  
Ricardo M. Brizuela ◽  
Karen J. Byer ◽  
W. Patrick Springhart ◽  
Saeed R. Khan ◽  
...  
Keyword(s):  
Cell Culture ◽  
Free Radical ◽  
Vitamin E ◽  
Mdck Cell ◽  
Cell Culture Model ◽  
Culture Model

3D in vitro reconstruction of synthetic liver sinusoids in a microfluidic cell culture device

2013 ◽  
Vol 51 (01) ◽  
Author(s):  
J Böttger ◽  
J Schütte ◽  
K Benz ◽  
C Freudigmann ◽  
B Hagmeyer ◽  
...  
Keyword(s):  
Cell Culture ◽  
Liver Sinusoids ◽  
Microfluidic Cell Culture

EVALUATION OF TISSUE STEROID BINDING IN VITRO

1971 ◽  
Vol 68 (1_Suppl) ◽  
pp. S223-S246 ◽  
Author(s):  
C. R. Wira ◽  
H. Rochefort ◽  
E. E. Baulieu
Keyword(s):  
Protein Binding ◽  
Binding Sites ◽  
Experimental System ◽  
Specific Protein ◽  
Coupling Mechanism ◽  
Target Tissue ◽  
Protein Binding Sites ◽  
Definition Of ◽  
Hormone Specificity

ABSTRACT The definition of a RECEPTOR* in terms of a receptive site, an executive site and a coupling mechanism, is followed by a general consideration of four binding criteria, which include hormone specificity, tissue specificity, high affinity and saturation, essential for distinguishing between specific and nonspecific binding. Experimental approaches are proposed for choosing an experimental system (either organized or soluble) and detecting the presence of protein binding sites. Techniques are then presented for evaluating the specific protein binding sites (receptors) in terms of the four criteria. This is followed by a brief consideration of how receptors may be located in cells and characterized when extracted. Finally various examples of oestrogen, androgen, progestagen, glucocorticoid and mineralocorticoid binding to their respective target tissues are presented, to illustrate how researchers have identified specific corticoid and mineralocorticoid binding in their respective target tissue receptors.

IN VITRO METHODS FOR THE STUDY OF THE ADENOHYPOPHYSIAL FUNCTIONS TO SECRETE GONADOTROPHIN

1971 ◽  
Vol 68 (1_Suppl) ◽  
pp. S27-S40 ◽  
Author(s):  
T. Kobayashi ◽  
T. Kigawa ◽  
M. Mizuno ◽  
T. Watanabe
Keyword(s):  
Cell Culture ◽  
Organ Culture ◽  
Cultured Cells ◽  
Cell Sheet ◽  
Short Term ◽  
Hypothalamic Extract ◽  
Numerous Cell ◽  
Single Cell Culture ◽  
Almost All

ABSTRACT There are several in vitro methods to analyse the function of the adenohypophysis or the mechanisms of its regulation. The present paper deals with single cell culture, organ culture and short term incubation techniques by which the morphology and gonadotrophin-secreting function of the adenohypophysis were studied. In trypsin-dispersed cell culture, the adenohypophysial cells showed extensive propagation to form numerous cell colonies and finally develop into a confluent monolayer cell sheet covering completely the surface of culture vessels. Almost all of the cultured cells, however, became chromophobic, at least at the end of the first week of cultivation, when gonadotrophin was detectable neither in the culture medium nor in the cells themselves. After the addition of the hypothalamic extract, gonadotrophin became detectable again, and basophilic or PAS-positive granules also reappeared within the cells, suggesting that the gonadotrophs were stimulated by the extract to produce gonadotrophin. In organ culture and short term incubation, the incorporation of [3H] leucine into the adenohypophysial cells in relation to the addition of hypothalamic extract was examined. It was obvious that the ability to incorporate [3H] leucine into the gonadotrophs in vitro was highly dependent upon the presence of the hypothalamic extract.

Induction of melanocyte precursors from neural crest cells surrounding the neural tube-like structures developed in vitro using mouse ES cell culture

2007 ◽  
Vol 27 (1) ◽  
pp. 45-52
Author(s):  
Koh-ichi Atoh ◽  
Manae S. Kurokawa ◽  
Hideshi Yoshikawa ◽  
Chieko Masuda ◽  
Erika Takada ◽  
...  
Keyword(s):  
Cell Culture ◽  
Neural Crest ◽  
Neural Tube ◽  
Neural Crest Cells ◽  
Es Cell ◽  
Mouse Es Cell
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