scholarly journals In vivo assembly of tight junctions in fetal rat liver.

1975 ◽  
Vol 67 (2) ◽  
pp. 310-319 ◽  
Author(s):  
R Montesano ◽  
D S Friend ◽  
A Perrelet ◽  
L Orci
Keyword(s):  
Tight Junctions ◽  
De Novo ◽  
Early Stage ◽  
Fetal Life ◽  
Bile Canaliculi ◽  
Linear Arrays ◽  
Fetal Rat ◽  
Particle Aggregates ◽  
Fetal Rat Liver

Examination of glutaraldehyde-fixed, freeze-fractured livers from 14-15-day rat fetuses provided the basis for the following observations. Membrane particles align in otherwise poorly particulated areas of the presumptive pericanalicular plasma membrane (A face), frequently forming a discontinuous "honey-comb" network joining small particle islands. Even at this early stage, contiguous B-fracture faces contain furrows, rather than rows of pits, distinguishing the linear particle aggregates on the A face as developing tight junctions rather than gap junctions. Short segments of these linear arrays merge with smooth ridges clearly identifiable as segments of discontinuous tight junctions. With the continuing confluence of particulate and smooth ridge segments, mature tight junctions become fully appreciable. We conclude that tight junctions form de novo by the alignment and fusion of separate particles into beaded ridges which, in turn, become confluent and are transformed into continuous smooth ones. At 21 days of fetal life, most of the images of assembly have disappeared, and the liver reveals well-formed bile canaliculi sealed by mature tight junctions.

Bioelectric properties of cultured epithelial monolayers from distal lung of 18-day fetal rat

1992 ◽  
Vol 262 (5) ◽  
pp. L628-L636 ◽  
Author(s):  
P. M. Barker ◽  
A. D. Stiles ◽  
R. C. Boucher ◽  
J. T. Gatzy
Keyword(s):  
Short Circuit ◽  
In Vivo Studies ◽  
Fetal Life ◽  
Pulmonary Epithelium ◽  
Fresh Tissue ◽  
Fetal Sheep ◽  
Ussing Chambers ◽  
Cl Secretion ◽  
Fetal Rat

In vivo studies of fetal sheep suggest that the liquid present in the lumen of the lung throughout fetal life is derived from Cl- secretion by the pulmonary epithelium. Monolayer preparations of enriched epithelial cells from distal fetal rat (18-day gestation) lung, grown in serum-free media, were histologically similar to acinar (prealveolar) structures of fresh tissue. In Ussing chambers, basal transepithelial potential difference (PD), calculated equivalent short-circuit current (Ieq), and transepithelial resistance (R) were 4.4 +/- 0.3 mV (matrix positive), 35.6 +/- 1.6 microA/cm2, and 120.0 +/- 4.0 omega cm2, respectively. Ouabain (10(-3) M) eliminated 57% of basal Ieq within 30 min, amiloride (10(-4) M) induced a 13% fall in Ieq, and phlorizin (10(-4) M) had no effect on bioelectric properties. Diphenylamine-2-carboxylate (DPC, 3 x 10(-3) M) inhibited Ieq by 50%. Bumetanide had no effect on baseline bioelectric parameters. The hyperpolarization that accompanied apical or bilateral replacement of Cl- and was enhanced by terbutaline suggested an apical Cl- permselectivity. Effects of Na+ replacement on amiloride-pretreated monolayers were consistent with Na(+)-dependent Cl- secretion or amiloride-insensitive pathways. Under these growth conditions, this preparation exhibits bioelectric characteristics that are compatible with Cl- secretion and Na+ absorption. The mechanism of Cl- secretion may be similar to that of airways but is uniquely bumetanide insensitive.

scholarly journals Conversion of ethanolamine, monomethylethanolamine and dimethylethanolamine to choline-containing compounds by neurons in culture and by the rat brain

1989 ◽  
Vol 264 (2) ◽  
pp. 555-562 ◽  
Author(s):  
C Andriamampandry ◽  
L Freysz ◽  
J N Kanfer ◽  
H Dreyfus ◽  
R Massarelli
Keyword(s):  
Rat Brain ◽  
Primary Culture ◽  
De Novo ◽  
Water Soluble ◽  
Intraventricular Injection ◽  
Chick Embryos ◽  
Fetal Rat ◽  
Derivatives Of ◽  
The Brain

The incubation of neurons from chick embryos in primary culture with [3H]ethanolamine revealed the conversion of this base into monomethyl, dimethyl and choline derivatives, including the corresponding free bases. Labelling with [methyl-3H]monomethylethanolamine and [methyl-3H]dimethylethanolamine supported the conclusion that in chick neuron cultures, phosphoethanolamine appears to be the preferential substrate for methylation, rather than ethanolamine or phosphatidylethanolamine. The methylation of the latter two compounds, in particular that of phosphatidylethanolamine, was seemingly stopped at the level of their monomethyl derivatives. Fetal rat neurons in primary culture incubated with [3H]ethanolamine showed similar results to those observed with chick neurones. However, phosphoethanolamine and phosphatidylethanolamine and, to a lesser extent, free ethanolamine, appeared to be possible substrates for methylation reactions. The methylation of water-soluble ethanolamine compounds de novo was further confirmed by experiments performed in vivo by intraventricular injection of [3H]ethanolamine. Phosphocholine and the monomethyl and dimethyl derivatives of ethanolamine were detected in the brain 15 min after injection.

Evolution et controle de l'activité de l'amylo-1,6-glucosidase du foie foetal de rat

1979 ◽  
Vol 57 (10) ◽  
pp. 1245-1249
Author(s):  
R. Vaillant ◽  
P. Bourgeois-Victor ◽  
A. Fairand
Keyword(s):  
Growth Hormone ◽  
Hormonal Regulation ◽  
Enzymic Activity ◽  
Fetal Life ◽  
Glucosidase Activity ◽  
Hormone Administration ◽  
Fetal Rat ◽  
Repressive Effect ◽  
Regulation Mechanisms ◽  
Fetal Rat Liver

The development of amylo-1,6-glucosidase activity is studied in fetal rat liver. The activity of control fetuses is high on day 17.5, decreases from day 17.5 to day 19.5, and then rises during the next days. In hypophysectomised fetuses, the increase of the activity is suppressed but not the decrease. Moreover, if the mother is adrenalectomized the decrease and the increase are abolished in hypophysectomised fetuses. Growth hormone administration is quite effective in preventing the decrease in enzyme activity but cortisol treatment does not prevent it. In contrast, cortisol produces a precocious decrease of the activity in intact fetuses. These findings suggest that during fetal life, two hormonal regulation mechanisms are involved in the regulation of amylo-1,6-glucosidase activity: cortisol has a repressive effect on the enzymic activity while growth hormone acts as an inducer.

Immunolocalization of prosomal proteins in adult and fetal rat liver outline the bile canaliculi

1990 ◽  
Vol 14 ◽  
pp. 202
Author(s):  
D BRIANS ◽  
M OLINKCOUX ◽  
J VASSY ◽  
J RIGAUT ◽  
K SCHERRER ◽  
...  
Keyword(s):  
Rat Liver ◽  
Bile Canaliculi ◽  
Fetal Rat ◽  
Fetal Rat Liver

scholarly journals SITES OF GLYCOGEN SYNTHESIS IN RAT LIVER CELLS AS SHOWN BY ELECTRON MICROSCOPE RADIOAUTOGRAPHY AFTER ADMINISTRATION OF GLUCOSE-H3

1966 ◽  
Vol 30 (1) ◽  
pp. 151-175 ◽  
Author(s):  
Antonio Coimbra ◽  
C. P. Leblond
Keyword(s):  
De Novo ◽  
Early Stage ◽  
Glycogen Synthesis ◽  
Light And Electron Microscopy ◽  
Rat Liver Cells ◽  
Silver Grains ◽  
Fasted Rats ◽  
Partly Smooth

Glycogen synthesis was investigated by giving tritium (H3)-labeled glucose with carrier to fasted rats in vivo or incubating liver slices from fasted rats in vitro using a glucose-H3-containing medium. After 15 min or 1 hr, pieces of liver were fixed and radioautographed for light and electron microscopy. In vivo and in vitro, radioautographic reactions appeared over "glycogen areas" and over zones transitional between these areas and ergastoplasm. Treatment of sections by alpha amylase removed all but about 5% of the radioactivity, so that about 95% of it consisted of glycogen (synthesized during the 15 min or 1 hr elapsing after administration of glucose-H3). Within glycogen areas and transitional zones, most silver grains were over or very close to glycogen granules and smooth (or partly smooth) vesicles. Presumably, much of the label was added onto growing glycogen granules, in accord with the biochemical view that glycogen may serve as substrate for further glycogen synthesis. The few silver grains located far from glycogen granules—15% at the 15 min interval in vivo—approximated smooth (or partly smooth) vesicles of endoplasmic reticulum. This observation raised the possibility that smooth membranes play a role in glucose uptake at an early stage in de novo formation of glycogen granules.

scholarly journals Adult rat hepatocytes in primary monolayer culture. Ultrastructural characteristics of intercellular contacts and cell membrane differentiations.

1977 ◽  
Vol 74 (3) ◽  
pp. 858-877 ◽  
Author(s):  
J C Wanson ◽  
P Drochmans ◽  
R Mosselmans ◽  
M F Ronveaux
Keyword(s):  
Tight Junctions ◽  
De Novo ◽  
Calf Serum ◽  
Rat Hepatocytes ◽  
Isolated Hepatocytes ◽  
Ruthenium Red ◽  
Bile Canaliculi ◽  
Isolated Cells ◽  
Etching Technique ◽  
Primary Monolayer

Primary monolayer cultures were obtained in 60-mm petri dishes by incubating 3 X 10(6) isolated hepatocytes at 37 degrees C in Dulbecco's medium supplemented with 17% fetal calf serum. The ultrastructure of monolayer cells was examined after various incubation periods. Within 4 h of plating, the isolated spherical cells adhere to the plastic surface, establish their first contacts by numerous intertwined microvilli, and form new hemidesmosomes. After 12 h of culture, wide branched trabeculae of flattened polyhedral cells extend in all directions. Finally, after 24 h of culture, bile canaliculi are reconstituted, and a biliary polarity is recovered: the Golgi elements, which are scattered throughout the cytoplasm in the isolated cells, are reassembled in front of the newly formed bile canalculi, symmetrically in the adjacent cells; lysosomes are concentrated in that region, and microtubules reappear. Concomitantly, plasma membrane differentiations, namely desmosomes and tight junctions, develop. Tight junctions sealing the bile ducts constitute a barrier to the passage of ruthenium red and horseradish peroxidase. De novo formation of these junctions was studied by the freeze-etching technique: 10-nm particles compose a network of anastomosed linear arrays in the vicinity of the bile canaliculi; in the next step of differentiation, the particles fuse, form short ridge segments and finally continuous branched smooth strands, characteristic of the mature tight junction.

scholarly journals Mutation of Ki-ras and N-ras oncogenes in myelodysplastic syndromes

Blood ◽  
1988 ◽  
Vol 71 (6) ◽  
pp. 1707-1712 ◽  
Author(s):  
J Lyons ◽  
JW Janssen ◽  
C Bartram ◽  
M Layton ◽  
GJ Mufti
Keyword(s):  
Myelodysplastic Syndromes ◽  
De Novo ◽  
Early Stage ◽  
Refractory Anemia ◽  
In Vivo Model ◽  
Ras Mutation ◽  
Mutational Status ◽  
Oligonucleotide Hybridization

Abstract Somatic mutation of the N-ras oncogene occurs frequently in de novo acute myeloid leukemia (AML). By virtue of their relation to AML, myelodysplastic syndromes (MDS) provide an in vivo model of human leukemogenesis. By using a strategy for analysis of gene mutation based on in vitro amplification of target sequences by the polymerase chain reaction (PCR) and selective oligonucleotide hybridization we analyzed the mutational status of codons 12, 13, and 61 of Ha-ras, K-ras, and N- ras in peripheral blood (PB) and/or bone marrow (BM) in 34 cases of primary MDS. Mutations at codon 12 of Ki-ras or N-ras were detected in three cases (9%): one of six cases of refractory anemia with excess blasts (RAEB) and two of nine cases of chronic myelomonocytic leukemia (CMML). The nucleotide substitution differed in each. In all cases the mutant allele was detectable in PB cells. A sustained hematologic remission was achieved after low-dose cytarabine therapy in the case of RAEB. Neither case of CMML exhibited signs of disease progression during follow-up at 7 and 12 months. In contrast, four of 31 patients without the ras mutation underwent transformation to AML within 12 months of genetic analysis. We conclude that ras mutations in MDS are heterogeneous and may develop at an early stage during the evolution of MDS. Their detection in PB cells illustrates the potential utility of ras mutation as a clonal marker in myeloid malignancy.

scholarly journals Distributions of vimentin and desmin in developing chick myotubes in vivo. II. Immunoelectron microscopic study.

1985 ◽  
Vol 100 (4) ◽  
pp. 1157-1166 ◽  
Author(s):  
K T Tokuyasu ◽  
P A Maher ◽  
S J Singer
Keyword(s):  
Intermediate Filaments ◽  
De Novo ◽  
Early Stage ◽  
Primary Role ◽  
Special Relationship ◽  
Frozen Sections ◽  
Intermediate Filament Proteins ◽  
Immunofluorescence Studies ◽  
Ultrathin Frozen Sections

The distribution of the intermediate filament proteins vimentin and desmin in developing and mature myotubes in vivo was studied by single and double immunoelectron microscopic labeling of ultrathin frozen sections of iliotibialis muscle in 7-21-d-old chick embryos, and neonatal and 1-d-old postnatal chicks. This work is an extension of our previous immunofluorescence studies of the same system (Tokuyasu, K. T., P. A. Maher and S. J. Singer, 1984, J. Cell Biol., 98:1961-1972). In immature myotubes of 7-11-d embryos, significant labeling for desmin and vimentin was found only in intermediate filaments, and these proteins coexisted in the same individual filaments. Each of the two proteins was present in irregular clusters along the entire length of a filament. No exclusively vimentin- or desmin-containing filaments were observed at this stage. In the early myotubes, the intermediate filaments were essentially all longitudinally oriented, even when they contained three times as much desmin as vimentin. No special relationship was recognized between the dispositions of the filaments and the organization of the myofibrils. Occasionally, several myofibrils were already aligned in lateral registry at this early stage, but labeling for desmin and vimentin was largely absent at the level of the Z bands. Instead, the Z bands appeared to be covered by elements of the sarcoplasmic reticulum. The confinement of intermediate filaments to the level of the Z bands occurred in the myotubes of later embryos after the extensive lateral registry of the Z bands. Thus, intermediate filaments are unlikely to play a primary role in producing the lateral registration of myofibrils during myogenesis, but may be important in determining the polarization of the early myotube and the alignment of its organelles. Throughout the development of myotubes, desmin and vimentin remained in the form of intermediate filaments, although the number of filaments per unit volume of myotube appeared to be reduced as myofibrils increased in number in maturing myotubes. This observation indicated that the transverse orientation of intermediate filaments in mature myotubes does not result from the de novo polymerization of subunits from Z band to Z band, but a continuous shifting of the positions and directions of intact filaments.

scholarly journals Pre-implantation alcohol exposure induces lasting sex-specific DNA methylation programming errors in the developing forebrain

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
L. M. Legault ◽  
K. Doiron ◽  
M. Breton-Larrivée ◽  
A. Langford-Avelar ◽  
A. Lemieux ◽  
...  
Keyword(s):  
Dna Methylation ◽  
De Novo ◽  
Prenatal Alcohol Exposure ◽  
Alcohol Exposure ◽  
Fetal Life ◽  
Fetal Alcohol ◽  
Cell Stage ◽  
Genome Wide ◽  
Fetal Alcohol Spectrum

Abstract Background Prenatal alcohol exposure is recognized for altering DNA methylation profiles of brain cells during development, and to be part of the molecular basis underpinning Fetal Alcohol Spectrum Disorder (FASD) etiology.  However, we have negligible information on the effects of alcohol exposure during pre-implantation, the early embryonic window marked with dynamic DNA methylation reprogramming, and on how this may rewire the brain developmental program. Results Using a pre-clinical in vivo mouse model, we show that a binge-like alcohol exposure during pre-implantation at the 8-cell stage leads to surge in morphological brain defects and adverse developmental outcomes during fetal life. Genome-wide DNA methylation analyses of fetal forebrains uncovered sex-specific alterations, including partial loss of DNA methylation maintenance at imprinting control regions, and abnormal de novo DNA methylation profiles in various biological pathways (e.g., neural/brain development). Conclusion These findings support that alcohol-induced DNA methylation programming deviations during pre-implantation could contribute to the manifestation of neurodevelopmental phenotypes associated with FASD.

Evidence for glucocorticosteroid receptors in the erythroid cell line of fetal rat liver

1983 ◽  
Vol 96 (2) ◽  
pp. 311-319 ◽  
Author(s):  
P. Mayeux ◽  
C. Billat ◽  
J. M. Felix ◽  
R. Jacquot
Keyword(s):  
Activated Charcoal ◽  
Fetal Liver ◽  
Deae Cellulose ◽  
Erythroid Cell ◽  
Supernatant Fraction ◽  
Major Peak ◽  
Fetal Rat ◽  
Fetal Rat Liver ◽  
Macromolecular Component

A role for glucocorticosteroids in the evolution of the rat fetal liver erythropoiesis in vivo has been proposed; accordingly suppressible binding of [3H]dexamethasone by intact liver erythroid cells at 4 °C has been described. The nature of this binding was further investigated in the present paper. Suspensions of cells of the erythroid line were prepared from liver erythropoietic tissue obtained from fetuses aged 15 or 16 days. Suppressible binding of [3H]dexamethasone was studied on these suspensions. After incubation at 4 °C, approximately 89 per cent of this binding was located in the cytosol (100 000 g supernatant fraction), was excluded from Sephadex G-50 columns and was not adsorbed on activated charcoal; 11·3 ± 2·6 (s.d.) per cent (n = 4) of the suppressible binding was present in the nucleus. When cells prelabelled with [3H]dexamethasone at 4 °C were warmed to 37 °C, 52 ± 10 per cent (n = 5) of the suppressible binding was rapidly transferred to the nucleus. The suppressible radioactivity present in the cytosols at 4 °C was eluted from diethylaminoethyl (DEAE)–cellulose columns, in the presence of molybdate, as a single peak (peak II) at phosphate concentrations between 200 and 250 mmol/l. When these cytosols were warmed at 25 °C before chromatography, the radioactivity was eluted from DEAE-cellulose as a major peak (peak I) at phosphate concentrations between 50 and 70 mmol/l, and as a smaller peak corresponding to peak II. The presence of molybdate during the incubation at 25 °C prevented the formation of peak I. The suppressible binding present in the cytosols of cells incubated at 37 °C was eluted from DEAE–cellulose columns in two equivalent peaks corresponding to peaks I and II. It was concluded that [3H]dexamethasone was bound to a macromolecular component sharing the properties generally ascribed to the receptor of glucocorticosteroids.

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