scholarly journals Retention of antidiuretic hormone-induced particle aggregates by luminal membranes separated from toad bladder epithelial cells.

1982 ◽  
Vol 92 (1) ◽  
pp. 237-241 ◽  
Author(s):  
R M Hays ◽  
J Bourguet ◽  
B H Satir ◽  
N Franki ◽  
J Rapoport
Keyword(s):  
Antidiuretic Hormone ◽  
Intact Cell ◽  
Collecting Duct ◽  
Freeze Fracture ◽  
High Yield ◽  
Starting Point ◽  
Particle Aggregates ◽  
Fracture Study ◽  
Bladder Cells ◽  
Membrane Components

Aggregates of intramembrane particles appear in the luminal membranes of renal collecting duct and amphibian bladder cells after stimulation by antidiuretic hormone (ADH). We undertook this freeze-fracture study to determine whether particle aggregates, once in place, remain in the luminal membrane of the amphibian bladder after the membrane is physically separated from the rest of the cell. We found that the aggregates do remain in high yield in isolated membranes stabilized with a bifunctional imidoester (DTBP) followed by fixation with glutaraldehyde, or unfixed but stabilized with DTBP. These findings support the view that the particles are intrinsic membrane components and that their organization in the form of aggregates does not depend on the presence of the intact cell. In addition, the availability of isolated membranes containing particle aggregates provides a starting point for the isolation of the water-conducting proteins.

Antidiuretic hormone-induced intramembranous alterations in mammalian collecting ducts

1978 ◽  
Vol 235 (5) ◽  
pp. F440-F443 ◽  
Author(s):  
Mehmet C. Harmanci ◽  
William A. Kachadorian ◽  
Heinz Valtin ◽  
Vincent A. DiScala
Keyword(s):  
Urinary Bladder ◽  
Antidiuretic Hormone ◽  
Collecting Duct ◽  
Freeze Fracture ◽  
Intramembranous Particle ◽  
Membrane Effect ◽  
Collecting Ducts ◽  
Amphibian Urinary Bladder ◽  
Freeze Fracture Electron Microscopy ◽  
Membrane Particle

Freeze-fracture electron microscopy had previously revealed antidiuretic hormone-induced aggregates of intramembranous particles in amphibian urinary bladder. To investigate the effects of antidiuretic hormone (ADH) in another ADH-sensitive epithelium, namely, mammalian renal collecting ducts, freeze-fracture studies were carried out in Brattleboro homozygous rats. Collecting duct luminal membranes of ADH-treated homozygotes showed intramembranous particle clusters (117 ± 17/100 μm2) that were loosely packed and that occurred on both exoplasmic (E) and protoplasmic (P) faces. Untreated, control homozygous rats had significantly less (3 ± 1/100 μm2) clusters. Changes similar to those seen in ADH-treated rats were observed in water-deprived Wistar rats. The clustered particles differed from those seen in ADH-treated amphibian urinary bladder in that the latter occurred only on the P face and were more densely packed. Nevertheless, our observations suggest a common membrane effect for ADH action that may apply in mammals and amphibia alike. freeze-fracture; Brattleboro homozygous rats; membrane particle clusters Submitted on March 6, 1978 Accepted on July 14, 1978

Antidiuretic hormone moves membranes

1988 ◽  
Vol 255 (3) ◽  
pp. F375-F382 ◽  
Author(s):  
J. S. Handler
Keyword(s):  
Plasma Membrane ◽  
Antidiuretic Hormone ◽  
Water Permeability ◽  
Apical Membrane ◽  
Collecting Duct ◽  
Toad Bladder ◽  
Cell Swelling ◽  
Apical Plasma Membrane ◽  
Principal Cells ◽  
Particle Aggregates

This review focuses on events at the apical plasma membrane of toad urinary bladder and mammalian collecting duct as their permeability to water changes in response to antidiuretic hormone (ADH) and to its withdrawal. The major marker of the permeability change is observed in freeze-fracture electron microscopy of the apical plasma membrane and consists of a dramatic increase in membrane particle aggregates and, in toad bladder but not in collecting duct, in fused vesicles (aggrephores) that contain particle aggregates in their limiting membranes. Withdrawal of ADH is accompanied by endocytosis at the apical membrane, reflecting retrieval of water-permeable, particle aggregate-containing membrane. Covalent labeling of the external surface of the apical membrane of toad bladder identifies specific proteins that are present in the apical membrane only during the response to ADH. Proteins of the same molecular weights are also present in the retrieved membrane when ADH is withdrawn. Several controversial areas are considered, including the extent of cell swelling as water flows across the epithelium from dilute apical solution to isotonic basal solution, whether only principal cells or principal cells and intercalated cells participate in the water permeability response of the collecting duct, the role of the cytoskeleton in the water permeability response, and the proposed second water permeability barrier that is affected by ADH, but not by adenosine 3',5'-cyclic monophosphate.

scholarly journals Development, Validation and Application of a UHPLC-MS Method for the Quantification of Chios Mastic Gum Triterpenoids in Human Plasma

Planta Medica ◽  
2021 ◽  
Author(s):  
Vincent Brieudes ◽  
Eleni V. Mikropoulou ◽  
Errikos Kallergis ◽  
Andriana C. Kaliora ◽  
Efstathia Papada ◽  
...  
Keyword(s):  
Human Plasma ◽  
Biological Fluids ◽  
Structural Characteristics ◽  
Biological Properties ◽  
Lipid Lowering ◽  
High Yield ◽  
Limit Of Quantification ◽  
Isolation And Characterization ◽  
Starting Point ◽  
Chios Mastic Gum

AbstractChios mastic gum is the resinous secretion obtained from the barks of the shrub Pistacia lentiscus var. Chia, which is endemic to the Greek island of Chios. Since antiquity, Chios mastic gum has found several uses as a phytotherapeutic remedy, primarily for the treatment of gastrointestinal disorders while recently, Chios mastic gum was also recognized by EMA as an herbal medicinal product with specific indications. Chios mastic gumʼs biological properties are attributed to triterpenes which comprise the major chemical group (approx. 70%) and notably isomasticadienonic acid and masticadienonic acid. However, due to their structural characteristics, the isolation thereof in high yield and purity is challenging and since they are not commercially available, pharmacological studies aiming to assess their biological properties are limited. In the present work, masticʼs phytochemical investigation by UPLC-HRMS is followed by the isolation and characterization of isomasticadienonic acid and masticadienonic acid to be used as analytical standards for their accurate and reliable quantification in human plasma. A UHPLC-tQ-MS method that was developed and validated (in terms of specificity, linearity, limit of quantification, accuracy and precision), for the direct quantification of the targeted compounds in the low ng/mL range of concentration, was subsequently implemented on plasma samples of healthy volunteers thus demonstrating its fitness for purpose. The results presented herein might provide insight to the understanding of this traditional natural product consumed notably for its anti-inflammatory, antioxidant and lipid lowering properties. Moreover, this method might serve as a starting point for any study aiming to monitor bioactive triterpenes in biological fluids.

Junctional Pattern in the Squamous Metaplasia of the Female Trigone. A Freeze-Fracture Study

1983 ◽  
Vol 129 (2) ◽  
pp. 280-283 ◽  
Author(s):  
M. Sideri ◽  
G. De Virgiliis ◽  
R. Rainoldi ◽  
A. Ferrari ◽  
G. Remotti
Keyword(s):  
Squamous Metaplasia ◽  
Freeze Fracture ◽  
Fracture Study

Freeze-fracture study of the mechanoreceptive digital corpuscles of mice

1985 ◽  
Vol 14 (6) ◽  
pp. 1037-1052 ◽  
Author(s):  
Chizuka Ide ◽  
Kenichi Kumagai ◽  
Schuichiro Hayashi
Keyword(s):  
Freeze Fracture ◽  
Fracture Study

scholarly journals Human erythrocytes adhering to schistosomula of Schistosoma mansoni lyse and fail to transfer membrane components to the parasite.

1985 ◽  
Vol 101 (1) ◽  
pp. 158-166 ◽  
Author(s):  
J P Caulfield ◽  
C M Cianci
Keyword(s):  
Schistosoma Mansoni ◽  
Erythrocyte Membrane ◽  
Plasma Membranes ◽  
Freeze Fracture ◽  
Human Erythrocytes ◽  
Transmission Microscopy ◽  
Carbocyanine Dyes ◽  
Host Membrane ◽  
Membrane Components ◽  
20 Nm

We studied the adherence of human erythrocytes to larvae of the intravascular parasite Schistosoma mansoni by transmission microscopy, freeze fracture, and fluorescence techniques. In addition, we used the adherent cells to investigate the problem of host antigen acquisition. Schistosomula were cultured for from 24 to 48 h after transformation in order to clear the remnants of the cercarial glycocalyx. In some cases, the worms were preincubated with wheat germ agglutinin to promote adherence of the erythrocytes. The results were similar with and without the lectin except that more cells attached to the lectin-coated parasites. Erythrocytes adhered within a few hours and, unlike neutrophils, did not fuse with the parasite. A layer of 10-20-nm electron dense material separated the outer leaflets of the tegumental and plasma membranes. In addition, many deformed and lysed cells were seen on the parasite surface. The ability of the worm to acquire erythrocyte membrane constituents was tested with carbocyanine dyes, fluorescein covalently conjugated to glycophorin, monoclonal antibodies against B and H blood group glycolipids, and rabbit alpha-human erythrocyte IgG. In summary, glycophorin, erythrocyte proteins, and glycolipids were not transferred to the parasite membrane within 48 h. Carbocyanine dyes were rapidly transferred to the parasite with or without lectin preincubation. Thus, the dye in the worm membrane came from both adherent and nonadherent cells. These studies suggest that, in the absence of membrane fusion, the parasite may acquire some lipid molecules similar in structure to host membrane glycolipids by simple transfer through the medium but that B and H glycolipids and erythrocyte membrane proteins are not transferred from adhering cells to the worm.

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