Locomotion and cell-substratum contacts of Xenopus epidermal cells in vitro and in situ

1980 ◽  
Vol 44 (1) ◽  
pp. 201-223
Author(s):  
G.P. Radice
Keyword(s):  
Wound Closure ◽  
Time Lapse ◽  
Epidermal Cells ◽  
Tissue Cell ◽  
Basal Cells ◽  
Closure Time ◽  
Transmission Electron

Studies of tissue cell locomotion in culture have revealed much about cell motility, but whether behaviour in vitro resembles movement of the same cells in the animal is not clear. To investigate this, I compared the locomotion and cell-substratum contacts of epidermal cells from Xenopus tadpoles, migrating from explants on glass and plastic, with the same cells spreading in vivo during wound closure. Time-lapse cinemicrography showed that in both cases, cells spread by extending broad lamellipodia across the substratum, and did not form microspikes, filopodia, or blebs. The net rate of translocation was significantly slower in vitro, however, because cells both protruded lamellipodia slower and spent more time stationary or withdrawing, compared with cells in situ. The increased fluctuation seemed in part due to greater tension within the expanding sheet in vitro, since when tension was reduced, for example by wounding, the cells spread with less fluctuation and at a greater rate (6.5 micrometers/min compared with 0.77 micrometers/min). Micromanipulation showed that cells adhered to the substratum, both in situ and in vitro, by a broad contact where transmission electron microscopy (TEM) of sectioned material showed the cells to be less than 30 nm from the substratum. A similar separation was observed beneath cells in vitro when viewed in life with interference-reflexion optics (IRM). A few focal contacts (adhesion plaques) were also seen with IRM and TEM of cells in vitro, but were not seen with TEM of cells in situ. Submarginal as well as marginal basal cells of the advancing sheet adhere and spread on the substratum in both situations, whereas cells of the outer layer are passive. Hence, the overall pattern of migration of these cells is similar in vitro and in situ; the differences in rates of movement may be explained in part by the different degree of tension in the epithelium under the 2 conditions.

scholarly journals In vivo measurement of pH, CO2 and HCO3- levels in the uterus of non-anesthetized sows through the estrous cycle and after insemination

2020 ◽  
Author(s):  
Octavio López Albors ◽  
Pedro José Llamas-López ◽  
Joaquín Ortuño ◽  
Rafael Latorre ◽  
Francisco Alberto García Vázquez
Keyword(s):  
Estrous Cycle ◽  
Time Lapse ◽  
Invasive Approach ◽  
In Vivo Measurement ◽  
Non Invasive ◽  
Reproductive Techniques ◽  
Physiological Values

Abstract Background The pH-CO2-HCO3− system is a ubiquitous biological regulator with important functional implications for reproduction. Knowledge of the physiological values of its components is relevant for reproductive biology and the optimization of Assistant Reproductive Techniques (ARTs). In vivo pH of the oviduct and uterus has been estimated by direct in situ measurements in a few species. However, regarding the levels of CO2 and HCO3−, information is very scarce and, when available, it comes from fluid samples instead of in vivo estimations. This study describes a non-invasive method to measure pH and % of CO2 in the uterus of sows with cutting-edge technology and no medication. Sows were at three different reproductive conditions, estrous with no insemination E(-)AI and after insemination E(+)AI, and diestrous (non-estrous, NE). From pH and CO2 data, HCO3− concentration was estimated. Results The designed methodology allowed for in situ time-lapse recording of pH and % of CO2 within the uterus of non-anesthetized sows. Variable oscillatory patterns of pH, CO2 and HCO3− were found independently of the estrous condition. Insemination did not changed the levels of uterine pH, % of CO2 and HCO3− concentration, -E(-)AI = E(+)AI-, but all the values were affected by the estrous cycle in a way that decreased significantly at diestrous condition - E(-)AI and E(+)AI > NE-. Conclusions A non-invasive approach to the porcine uterus with novel optical probes allowed the obtaining of in situ physiological values of pH, CO2, and HCO3− at different reproductive conditions. While the short-time presence of sperm in the uterus did not change the physiological milieu, the whole pH-CO2-HCO3− system was affected by the estrous cycle. This study contributes to a better understanding of the in vivo regulation of the pH/CO2/HCO3− system in the uterus and may help to optimize the protocols of sperm treatment for in vitro fertilization.

Early Stages in the Recovery to Injury in the Dorsal Fin of the Atlantic Cod (Gadus morhua)

1964 ◽  
Vol 21 (2) ◽  
pp. 347-354
Author(s):  
P. M. Townsley ◽  
M. L. Hughes
Keyword(s):  
Gadus Morhua ◽  
Wound Closure ◽  
Atlantic Cod ◽  
Epidermal Cells ◽  
Dorsal Fin ◽  
Early Stages ◽  
Close Proximity ◽  
Cell Mitosis

The early stages in the recovery of the dorsal fin of the Atlantic cod (Gadus morhua) to a "clean cut injury" are described. It is concluded that the observed rapid epidermal migration, wound closure and cell mitosis are essentially the same in in-vivo as in in-vitro experiments. An accumulation of carbohydrate material occurs in the outermost layer of epidermal cells. There is a change in the carbohydrate composition or structure in the dermal layers at the site of injury. The basal epidermal cells rapidly divide in the in-vitro culture whereas only those basal epidermal cells in an in-vivo injury in close proximity to the injury divide. The surrounding nutrient medium in in-vitro cultures does not appear to be involved in the initial cell migration. However, ascorbic acid does stimulate epidermal migration, mucous secretion, and basal epidermal cell mitosis.

Measurement of Cell Adhesion and Migration on Protein-Coated Surfaces

1991 ◽  
Vol 252 ◽  
Author(s):  
Paul A. DiMilla ◽  
Julie A. Stone ◽  
Steven M. Albelda ◽  
Douglas A. Lauffenburger ◽  
John A. Quinn
Keyword(s):  
Cell Adhesion ◽  
Critical Shear Stress ◽  
Cell Movement ◽  
Time Lapse ◽  
Tissue Cell ◽  
Cell Adhesion And Migration ◽  
And Migration ◽  
Coated Surfaces

ABSTRACTThe performance of biomaterials forin vivoandin vitroapplications can depend critically on tissue cell adhesion and migration. We have been investigating the role that specific reversible interactions between cell adhesion receptors and complementary substratum-bound ligands play in the regulation of cell adhesion and migration. With an axisymmetric radial flow detachment assay (RFDA) [1] we measured cell-substratum adhesive strength for human smooth muscle cells (HSMCs) on surfaces coated with type IV collagen (CIV). We found that the critical shear stress for detachment increased linearly with increasing CIV coating concentration. Using time-lapse videomicroscopy and image analysis we tracked the movement of individual HSMCs over similar CIV-coated surfaces. Cell speed and persistence were determined for variations in CIV coating concentration by applying a persistent random walk model for individual cell movement. Cell speed reached a maximum at an intermediate concentration of CIV, supporting the hypothesis that an optimal cell-substratum adhesiveness exists for HSMC movement. This combination of techniques for measuring adhesion and motility provides a valuable tool to examine the role of cell-biomaterial interactions on cell behavior.

scholarly journals Differential Expression of Hypothalamic and Gill-crh System With Osmotic Stress in the Euryhaline Black Porgy, Acanthopagrus schlegelii

2021 ◽  
Vol 12 ◽  
Author(s):  
Adimoolam Aruna ◽  
Tsan-Ping Wang ◽  
Jyun-Cing Cao ◽  
Dan-Suei Lan ◽  
Ganesan Nagarajan ◽  
...  
Keyword(s):  
Gill Filament ◽  
Pcr Analysis ◽  
Basal Cells ◽  
Acanthopagrus Schlegelii ◽  
Black Porgy ◽  
Secondary Lamellae ◽  
Mrna Hybridization

The local gill production of corticotropin releasing hormone (crh) and crh-receptor (crhr) is hypothesized to play important roles during seawater (SW) and freshwater (FW) acclimation in euryhaline black porgy (Acanthopagrus schlegelii). The mRNA expression of crh, crhr, and Na+/K+-ATPase (a-nka) was examined in SW and FW diencephalon (Dien) and in the gills at different exposure time by Q-PCR analysis. The in situ hybridization results indicate that crh mRNA hybridization signals were more abundant in FW fish in the gigantocellular (PMgc) and parvocellular (PMpc) part of the magnocellular preoptic nucleus versus SW fish. The crh and crhr-expressing cells were located in basal cells of gill filament. Furthermore, in vitro dexamethasone (DEX) treatment could increase the crh-system in the gill. Increased transcripts of the crh-system in the gill via in vitro and in vivo CRH treatments suggest that CRH may regulate the system in a local manner. The a-Nka cells were localized in the filament and secondary lamellae mitochondria rich cells (MRCs) of FW fish at 8 h and 1 day. a-Nka cells were seen in both filament and lamellae in the FW but much less in SW fish indicating that gills play key roles in black porgy osmoregulation. Gill crh and crhr play important roles in the response to salinity stress.

Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro

1978 ◽  
Vol 36 (2) ◽  
pp. 650-651
Author(s):  
Raul I. Garcia ◽  
Evelyn A. Flynn ◽  
George Szabo
Keyword(s):  
Direct Injection ◽  
Skin Pigmentation ◽  
Freeze Fracture ◽  
Pigment Granule ◽  
Time Lapse ◽  
Ultrastructural Level ◽  
Lanthanum Tracer ◽  
A Cell

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Evaluation of Structure-Controlled Silk Fibroin Coatings for Orthopedic Infection and In-Situ Osteogenesis: In Vitro and In Vivo

2020 ◽  
Author(s):  
Wenhao Zhou ◽  
Teng Zhang ◽  
Jianglong Yan ◽  
QiYao Li ◽  
Panpan Xiong ◽  
...  
Keyword(s):  
Silk Fibroin ◽  
Orthopedic Infection

scholarly journals Overexpression of the Oral Mucosa-Specific microRNA-31 Promotes Skin Wound Closure

2019 ◽  
Vol 20 (15) ◽  
pp. 3679 ◽  
Author(s):  
Lin Chen ◽  
Alyne Simões ◽  
Zujian Chen ◽  
Yan Zhao ◽  
Xinming Wu ◽  
...  
Keyword(s):  
Wound Healing ◽  
Oral Mucosa ◽  
Wound Closure ◽  
Expression Patterns ◽  
Skin Wound ◽  
Skin Wound Healing ◽  
Specific Expression ◽  
Keratinocyte Proliferation

Wounds within the oral mucosa are known to heal more rapidly than skin wounds. Recent studies suggest that differences in the microRNAome profiles may underlie the exceptional healing that occurs in oral mucosa. Here, we test whether skin wound-healing can be accelerating by increasing the levels of oral mucosa-specific microRNAs. A panel of 57 differentially expressed high expresser microRNAs were identified based on our previously published miR-seq dataset of paired skin and oral mucosal wound-healing [Sci. Rep. (2019) 9:7160]. These microRNAs were further grouped into 5 clusters based on their expression patterns, and their differential expression was confirmed by TaqMan-based quantification of LCM-captured epithelial cells from the wound edges. Of these 5 clusters, Cluster IV (consisting of 8 microRNAs, including miR-31) is most intriguing due to its tissue-specific expression pattern and temporal changes during wound-healing. The in vitro functional assays show that ectopic transfection of miR-31 consistently enhanced keratinocyte proliferation and migration. In vivo, miR-31 mimic treatment led to a statistically significant acceleration of wound closure. Our results demonstrate that wound-healing can be enhanced in skin through the overexpression of microRNAs that are highly expressed in the privileged healing response of the oral mucosa.

scholarly journals Development of In Situ Self-Assembly Nanoparticles to Encapsulate Lopinavir and Ritonavir for Long-Acting Subcutaneous Injection

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 904
Author(s):  
Irin Tanaudommongkon ◽  
Asama Tanaudommongkon ◽  
Xiaowei Dong
Keyword(s):  
Sustained Release ◽  
Trough Concentration ◽  
Self Assembly ◽  
Subcutaneous Injection ◽  
Drug Loading ◽  
Entrapment Efficiency ◽  
Long Acting

Most antiretroviral medications for human immunodeficiency virus treatment and prevention require high levels of patient adherence, such that medications need to be administered daily without missing doses. Here, a long-acting subcutaneous injection of lopinavir (LPV) in combination with ritonavir (RTV) using in situ self-assembly nanoparticles (ISNPs) was developed to potentially overcome adherence barriers. The ISNP approach can improve the pharmacokinetic profiles of the drugs. The ISNPs were characterized in terms of particle size, drug entrapment efficiency, drug loading, in vitro release study, and in vivo pharmacokinetic study. LPV/RTV ISNPs were 167.8 nm in size, with a polydispersity index of less than 0.35. The entrapment efficiency was over 98% for both LPV and RTV, with drug loadings of 25% LPV and 6.3% RTV. A slow release rate of LPV was observed at about 20% on day 5, followed by a sustained release beyond 14 days. RTV released faster than LPV in the first 5 days and slower than LPV thereafter. LPV trough concentration remained above 160 ng/mL and RTV trough concentration was above 50 ng/mL after 6 days with one subcutaneous injection. Overall, the ISNP-based LPV/RTV injection showed sustained release profiles in both in vitro and in vivo studies.

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