Developmental stages of fetal-type Leydig cells in prepubertal rats

Development ◽  
1989 ◽  
Vol 107 (2) ◽  
pp. 213-220
Author(s):  
T. Kuopio ◽  
J. Tapanainen ◽  
L.J. Pelliniemi ◽  
I. Huhtaniemi
Keyword(s):  
Cell Volume ◽  
Leydig Cells ◽  
Developmental Stages ◽  
Neonatal Period ◽  
Microscopic Analysis ◽  
Electron Microscopic ◽  
Adult Type ◽  
Average Cell ◽  
Average Cell Volume ◽  
Fetal Leydig Cells

Fetal Leydig cells were studied in rats during and after the perinatal-neonatal period by comparing changes in morphology, number and volume with changes in testicular steroids and serum luteinizing hormone (LH) concentration. Stereologic examination indicated regression of fetal Leydig cells in testis by showing that their total volume as well as the average cell volume decreased between prenatal day 20 and postnatal day 3. The total number and total volume of cells both increased between postnatal days 3 and 11 but the average cell volume did not change during the same time period. Determination of serum LH showed a close correlation between an increase in LH concentration and increases in total number and volume of cells. The combined number of fetal- and adult-type Leydig cells on day 20 was more than 20 times the number of fetal cells at 3 days of age. Electron microscopic analysis showed that fetal Leydig cells after birth formed conspicuous clusters, which were surrounded by a layer of envelope cells and extracellular material. Occasional dividing fetal Leydig cells and possible precursors of fetal or adult Leydig cells were observed. Mitoses of spindle-shaped pericordal cells were frequent during the neonatal period. During and after the second postnatal week fetal Leydig cells again showed signs of regression, indicated by disintegration of the cell clusters, a decrease in cell size, accumulation of collagen between the cells and a decrease in steroid content per cell.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of Average Cell Volume and Open Cell Content of Rigid Foams

1970 ◽  
Vol 6 (3) ◽  
pp. 131-134
Author(s):  
Donald M. Kurtz
Keyword(s):  
Cell Volume ◽  
Cell Content ◽  
Average Cell ◽  
Open Cell ◽  
Rigid Foams ◽  
Average Cell Volume

Abstract P111: Rheb-mTOR Signaling Pathway Regulates Cardiomyocyte Mass During Post-Neonatal Period

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Takahito Tamai ◽  
Shungo Hikoso ◽  
Tomokazu Murakawa ◽  
Jota Oyabu ◽  
Takafumi Oka ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Neonatal Period ◽  
Contractile Function ◽  
Microscopic Analysis ◽  
Mrna Translation ◽  
Premature Death ◽  
Mtor Pathway ◽  
Heart Weight ◽  
Electron Microscopic ◽  
Cross Sectional

Rheb (Ras homologue enriched in brain) is a major activator of mTOR. Rheb-mTOR pathway is a critical mechanism for maintenance of homeostasis, cell growth and stress response by regulating both protein synthesis and degradation. In this study, we attempted to clarify the role of Rheb-mTOR pathway in the heart using cardiac-specific Rheb-deficient mice (Rheb −/− ). We generated floxed Rheb mice and crossed them with transgenic mice expressing Cre recombinase in cardiac-specific mannner to generate Rheb −/− . Rheb −/− were born in Mendelian ratio, but they started to die 8 days after birth and all of them had died until 10 days after birth. Echocardiographic analysis revealed that chamber dimension and contractile function of Rheb −/− were indistinguishable from those of control mice (Rheb +/+ ) 5 days after birth. However, Rheb −/− exhibited cardiac dilatation and reduced contractility 8 days after birth (LV end diastolic dimension, Rheb −/− : 2.5±0.2 mm vs. Rheb +/+ : 2.1±0.2 mm, p<0.01, fractional shortening, Rheb −/− : 19.7 ± 9.7 % vs. Rheb +/+ : 48.6 ± 8.8 %, p<0.01). These suggest that Rheb −/− died of cardiac dysfunction and heart failure. Heart weight and cross-sectional area of cardiomyocytes were significantly lower in Rheb −/− 8 days after birth. Electron microscopic analysis revealed that the area of sarcomere was significantly lower in Rheb −/− cardiomyocytes. Expressions of sarcomeric proteins, such as myosin heavy chain, actin or desmin, were decreased in Rheb −/− , while the mRNA expression of desmin was significantly increased in Rheb −/− . Thus impairment of cardiomyocyte growth observed in Rheb −/− could be due to either increased degradation or decreased translation. Although autophagic activity was enhanced in Rheb −/− heart, ablation of Atg5, an essential molecule for autophagy, could not prevent premature death of Rheb −/− . On the other hand, polysome analysis revealed that the mRNA translation activity had decreased in Rheb −/− heart compared with Rheb +/+ . Thus, we concluded that Rheb-mTOR pathway in the heart is essential to regulate mRNA translation activity and protein synthesis, thereby to cardiomyocyte growth in neonatal period.

scholarly journals Cell tension and mechanical regulation of cell volume

2018 ◽  
Vol 29 (21) ◽  
pp. 0-0 ◽  
Author(s):  
Nicolas Perez Gonzalez ◽  
Jiaxiang Tao ◽  
Nash D. Rochman ◽  
Dhruv Vig ◽  
Evelyn Chiu ◽  
...  
Keyword(s):  
Cell Volume ◽  
Force Balance ◽  
Cell Cortex ◽  
Animal Cells ◽  
Mechanical Tension ◽  
Average Cell ◽  
Physical Size ◽  
Average Cell Volume ◽  
Cell Growth And Proliferation ◽  
Exclusion Method

Animal cells use an unknown mechanism to control their growth and physical size. Here, using the fluorescence exclusion method, we measure cell volume for adherent cells on substrates of varying stiffness. We discover that the cell volume has a complex dependence on substrate stiffness and is positively correlated with the size of the cell adhesion to the substrate. From a mechanical force–balance condition that determines the geometry of the cell surface, we find that the observed cell volume variation can be predicted quantitatively from the distribution of active myosin through the cell cortex. To connect cell mechanical tension with cell size homeostasis, we quantified the nuclear localization of YAP/TAZ, a transcription factor involved in cell growth and proliferation. We find that the level of nuclear YAP/TAZ is positively correlated with the average cell volume. Moreover, the level of nuclear YAP/TAZ is also connected to cell tension, as measured by the amount of phosphorylated myosin. Cells with greater apical tension tend to have higher levels of nuclear YAP/TAZ and a larger cell volume. These results point to a size-sensing mechanism based on mechanical tension: the cell tension increases as the cell grows, and increasing tension feeds back biochemically to growth and proliferation control.

scholarly journals Morphometric Assessment of Pulmonary Toxicity in the Rodent Lung

1991 ◽  
Vol 19 (4_part_1) ◽  
pp. 428-446 ◽  
Author(s):  
Dallas M. Hyde ◽  
David J. Magliano ◽  
Charles G. Plopper
Keyword(s):  
Cell Volume ◽  
Basal Lamina ◽  
Interstitial Cells ◽  
Nuclear Volume ◽  
Secretory Product ◽  
Average Cell ◽  
Interstitial Volume ◽  
Average Cell Volume ◽  
Morphometric Assessment ◽  
Cell Volumes

An overview of the epithelial and interstitial composition of rat respiratory airways shows complexity and variability. Airway epithelium varies in 1) different airway levels; 2) the types and ultrastructure of cells present; and 3) the abundance, type, and composition of stored secretory product. Unbiased sampling of airways is done using airway microdissection with a specific binary numbering system for airway generation. Vertical sections of selected airways are used to sample epithelium and interstitium. We determine the ratios of the volume of epithelial or interstitial cells to the total epithelial or interstitial volume (Vv). The surface of the epithelial basal lamina to the total epithelial or interstitial volume (Sv) is determined using point and intersection counting with a cycloid grid. Using the selector method on serial plastic sections, we determine the number of epithelial or interstitial cells per volume (Nv) of total epithelium or interstitium. We calculate the number of epithelial or interstitial cells per surface of epithelial basal lamina (Ns) by dividing Nv by Sv where the volumes are the same compartment. We calculate average cell volumes (v̄) for specific epithelial and interstitial cells by dividing the absolute nuclear volume by the ratio of the nucleus to cell volume (Vv). By multiplying the average cell volume (v̄) by the ratio of organellar volume to cell volume (Vv), we calculate the average organellar volume per cell. These unbiased stereological approaches are critical in a quantitative evaluation of toxicological injury of rat tracheobronchial airways.

scholarly journals BIOCHEMICAL AND MORPHOMETRIC PARAMETERS OF SOME ORGANS AND TISSUES OF HYBRID TILAPIA (OREOCHROMIS SPP.) FOR GROWING WITH USE OF PREPARATION ES-2

2018 ◽  
pp. 113-117
Author(s):  
Svetlana Vladimirovna Kotelnikova ◽  
Andrey Vyacheslavovich Kotelnikov ◽  
Alexander Nickolaevich Nevalennyy ◽  
Sergey Vladimirovich Ponomarev ◽  
Yulia Mikhailovna Shirina
Keyword(s):  
Lipid Peroxidation ◽  
Cell Volume ◽  
Control Group ◽  
Fish Feed ◽  
Prooxidant Effect ◽  
Average Cell ◽  
Liver Nuclei ◽  
Average Cell Volume ◽  
Experimental Group ◽  
Volume Decrease

The article studies the effect of addition into the feed of Sapropel extract (ES-2 preparation) on the intensity of lipid peroxidation in the liver and gills of hybrid tilapia ( Oreochromis spp. ), as well as on the morphofunctional state of its liver. Sapropel extract caused a decrease in the content of TBA-reactants in the tissues of tilapia liver by 17% compared to the control group. In gills the bioadditive resulted in the increased content of peroxide products by 24%. The introduction of ES-2 in fish feed resulted in reduction of spontaneous and ascorbate-dependent lipid peroxidation rate in the liver by 18%. In the gills of fish, under the influence of Sapropel, the rate of spontaneous lipid peroxidation increased by 27%, the rate of ascorbate-dependent lipid peroxidation - by 23%. The change in the intensity of peroxide processes under the influence of the fodder additive in fish organs is tissue-specific: antioxidant effect was recorded in the liver, prooxidant effect was observed in the gills. The introduction of the Sapropel extract does not lead to a change in the volume of liver nuclei in the test groups of tilapia, while the average cell volume in the experimental group was 37% lower than in the control group. The decrease in cell volume led to the increase in the nuclear-cytoplasmic ratio by 1.9 times in the experimental group compared to the control group. Hepatocyte cytoplasm volume decrease and nuclear-cytoplasmic ratio increase due to addition of ES-2 preparation into productive feed of hybrid tilapia would indicate a rise of functional activity of liver cells.

Preparatory Procedures for Electron Microscopic Analysis at the Molecular Level of Resolution

1978 ◽  
Vol 36 (3) ◽  
pp. 516-520
Author(s):  
F.J. Sjostrand
Keyword(s):  
Electron Microscope ◽  
Molecular Level ◽  
Microscopic Analysis ◽  
Resolving Power ◽  
Cellular Structures ◽  
Electron Microscopic ◽  
Systematic Analysis ◽  
Technical Developments ◽  
Thin Sectioning ◽  
Obvious Reason

In the 1940's and 1950's electron microscopy conferences were attended with everybody interested in learning about the latest technical developments for one very obvious reason. There was the electron microscope with its outstanding performance but nobody could make very much use of it because we were lacking proper techniques to prepare biological specimens. The development of the thin sectioning technique with its perfectioning in 1952 changed the situation and systematic analysis of the structure of cells could now be pursued. Since then electron microscopists have in general become satisfied with the level of resolution at which cellular structures can be analyzed when applying this technique. There has been little interest in trying to push the limit of resolution closer to that determined by the resolving power of the electron microscope.

Electron Microscopic Analysis of Myonecrosis Induced by a Pure Component Isolated From Rattlesnake Venom

1976 ◽  
Vol 34 ◽  
pp. 292-293
Author(s):  
Charlotte L. Ownby ◽  
David Cameron ◽  
Anthony T. Tu
Keyword(s):  
Gel Filtration ◽  
Microscopic Analysis ◽  
The United States ◽  
Exchange Chromatography ◽  
Pure Component ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
Mouse Muscle ◽  
Major Health Problem ◽  
Rattlesnake Venom

In the United States the major health problem resulting from snakebite poisoning is local tissue damage, i.e. hemorrhage and myonecrosis. Since commercial antivenin does not usually prevent such damage to tissue, a more effective treatment of snakebite-induced myonecrosis is needed. To aid in the development of such a treatment the pathogenesis of myonecrosis induced by a pure component of rattlesnake venom was studied at the electron microscopic level.The pure component, a small (4,300 mol. wt.), basic (isoelectric point of 9.6) protein, was isolated from crude prairie rattlesnake (Crotalus viridis viridis) venom by gel filtration (Sephadex G-50) followed by cation exchange chromatography (Sephadex C-25), and shown to be pure by electrophoresis. Selection of the myotoxic component was based on light microscopic observations of injected mouse muscle.

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