scholarly journals Immunocytochemical localization of peptidylglycine alpha-amidating monooxygenase enzymes (PAM) in human endocrine pancreas.

1993 ◽  
Vol 41 (3) ◽  
pp. 375-380 ◽  
Author(s):  
A Martínez ◽  
L M Montuenga ◽  
D R Springall ◽  
A Treston ◽  
F Cuttitta ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endocrine Cells ◽  
Endocrine Pancreas ◽  
Light And Electron Microscopy ◽  
Regulatory Peptides ◽  
Immunocytochemical Localization ◽  
Serial Sections ◽  
Immunogold Staining ◽  
Granule Membrane ◽  
Amidated Peptide

We studied the distribution of the enzymes that are involved in the post-translational alpha-amidation of regulatory peptides in human endocrine pancreas, using immunocytochemical methods for light and electron microscopy. Immunoreactivity for the two enzymes involved, peptidylglycine alpha-hydroxylating monooxygenase (PHM) and peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL), was located in the periphery of the islets of Langerhans and in ductal endocrine cells. Staining of reverse-face serial sections demonstrated that these immunoreactivities co-localize with glucagon but not with pancreatic polypeptide (PP), insulin, or somatostatin. Double immunogold staining for electron microscopy confirmed the previous results and revealed a different localization for each enzyme inside the secretory granule: PHM is present in the central core of the glucagon-containing granules, whereas PAL is predominantly located near the granule membrane. The existence of an amidated peptide, GLP1, in the A-cells explains the presence of peptidylglycine alpha-amidating monooxygenase enzymes (PAM) in these cells. The absence of the enzymes in the PR-cells raises the possibility that a different form of amidating enzyme may be involved in the post-translational processing of this peptide.

Ultrastructure of region of a low safety factor in inhomogeneous giant axon of the cockroach

1976 ◽  
Vol 39 (4) ◽  
pp. 900-908 ◽  
Author(s):  
M. Castel ◽  
M. E. Spira ◽  
I. Parnas ◽  
Y. Yarom
Keyword(s):  
Electron Microscopy ◽  
Glial Cells ◽  
Extracellular Space ◽  
Light And Electron Microscopy ◽  
Giant Axon ◽  
Serial Sections ◽  
Giant Axons ◽  
Chemical Synapses ◽  
Cytoplasmic Processes ◽  
Periaxonal Space

1. The structure of the ventral giant axons of the cockroach at the level of ganglion T3 was studied by means of light and electron microscopy. 2. From serial sections and cobalt injections, the axons diameter was found to range between 40 and 60 mum at the caudal end of ganglion T3; toward the center of T3 they narrow to 20-40 mum, and again expand to 30-45 mum anteriorly in ganglion T3. 3. Each giant axon sends off several branches, 1-15 mum in diameter, into the neuropil. The giant axons and the bases of their branches are enveloped by cytoplasmic processes of glial cells. The periaxonal space is about 100-200 A. 4. Distally the branches are devoid of glial envelopes and the extracellular space between the branches and other axonal profiles is about 200 A. Terminals with presumptive chemical synapses on the giant axon branches were found. Clear vesicles, 300-400 A in diameter, are seen clustered together. The width of the supposedly synaptic gap is about 100 A. 5. In some areas the branches and other axonal profiles form close appositions.

A Light and Electron Microscopic Study in Serial Sections of Skeletal and Extraocular Muscles in Mouse Myotonic Dystrophy

1974 ◽  
Vol 32 ◽  
pp. 6-7
Author(s):  
Bruce R. Pachter ◽  
Jacob Davidowitz ◽  
Goodwin M. Breinin
Keyword(s):  
Electron Microscopy ◽  
Animal Model ◽  
Myotonic Dystrophy ◽  
Skeletal Muscles ◽  
Light And Electron Microscopy ◽  
Hereditary Disease ◽  
Serial Sections ◽  
Electron Microscopic ◽  
Suitable Animal Model ◽  
Model Mouse

A suitable animal model (Mouse Strain Re-129 dy2j/dy2j) has been reported for myotonic dystrophy, a hereditary disease in which skeletal muscles degenerate. In the present study, another strain of mouse (Bar Harbor Strain C57BL/6J dy2j/dy2j), carrying this same myotonic gene (dy2j) was studied by light and electron microscopy (EM) in serial sections of epon embedded tissue.

Techniques Involved in the Acquisition of Serial Sections of the Atrioventricular Node for Light and Electron Microscopy

1968 ◽  
Vol 26 ◽  
pp. 226-227
Author(s):  
Sheila S. Emmett ◽  
J. C. Thaemert
Keyword(s):  
Electron Microscopy ◽  
Osmium Tetroxide ◽  
Light And Electron Microscopy ◽  
Atrioventricular Node ◽  
Electron Microscopic Level ◽  
Serial Sections ◽  
Electron Microscopic ◽  
Trapezoidal Shape ◽  
Old Mice

The acquisition of serial sections of the atrioventricular node for light and electron microscopy is a formidable task. Ordinary techniques are not adequate if the best possible results are to be achieved at the electron microscopic level. The techniques outlined below have proven to be valuable in locating and determining the position of the AV node.Whole hearts of 2-week old mice were fixed, in situ, by perfusion with 1% phosphate-buffered osmium tetroxide. The hearts were removed from the animals, sectioned transversely into 3 slices approximately equal in thickness, dehydrated in graded concentrations of ethanol and embedded in Epon 812. The block faces were trimmed to a trapezoidal shape ranging in size from 0.75 x 1 mm to 4 x 5 mm. Serial sections approximately 2 microns in thickness were cut with glass knives on a Porter-Blum MT-2 Ultramicrotome. While floating on a drop of water on the knife, each section was stretched with 1 drop of a 1:1, xylene in chloroform mixture applied directly to the section. The sections were picked up individually with a brush, transferred to a glass slide and oven dried for several hours prior to staining.

scholarly journals Localization of amidating enzymes (PAM) in rat gastrointestinal tract.

1993 ◽  
Vol 41 (11) ◽  
pp. 1617-1622 ◽  
Author(s):  
A Martínez ◽  
M A Burrell ◽  
M Kuijk ◽  
L M Montuenga ◽  
A Treston ◽  
...  
Keyword(s):  
Small Intestine ◽  
In Situ Hybridization ◽  
Gastrointestinal Tract ◽  
Digestive Tract ◽  
Endocrine Cells ◽  
Regulatory Peptides ◽  
Serial Sections ◽  
Gastric Glands ◽  
Amidating Enzymes

We studied the distribution of the two enzymes involved in post-translational C-terminal alpha-amidation of regulatory peptides in rat digestive tract, using immunocytochemical methods and in situ hybridization techniques. The enzymes were located in most of the fibers and neurons of the myenteric and submucous plexus throughout the entire digestive tract and in endocrine cells of the stomach and colon. Staining of reverse-face serial sections demonstrated that the enzymes in endocrine cells of the stomach co-localized with gastrin in the bottom of the gastric glands. Some gastrin-immunoreactive cells near the neck of the gland were negative for PAM, suggesting that amidation takes place only in the more mature cells. In the colon all cells immunoreactive for glucagon and GLP1 were also positive for peptidylglycine alpha-hydroxylating monooxygenase (PHM) but not for peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL). The absence of immunoreactivity for the amidating enzymes in endocrine cells of the small intestine, known to produce C-terminally amidated peptides, suggests the existence of other amidating enzymes.

scholarly journals The larval midgut of Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae): light and electron microscopy studies of the epithelial cells

2004 ◽  
Vol 64 (3b) ◽  
pp. 633-638 ◽  
Author(s):  
S. M. Levy ◽  
A. M. F. Falleiros ◽  
E. A. Gregório ◽  
N. R. Arrebola ◽  
L. A. Toledo
Keyword(s):  
Electron Microscopy ◽  
Endocrine Cells ◽  
Secretory Granules ◽  
Light And Electron Microscopy ◽  
Cell Types ◽  
Anticarsia Gemmatalis ◽  
Epithelial Tissue ◽  
Basal Region ◽  
Transmission Electron ◽  
Basal Portion

The morphology of the midgut epithelium cells of Anticarsia gemmatalis (Hübner) larvae is described by light and transmission electron microscopy. The midgut of A. gemmatalis is the largest portion of the digestive tract, with three distinct regions: proximal, media and distal. Its wall is formed by pseudostratified columnar epithelial tissue having four cell types: columnar, goblet, regenerative, and endocrine cells. The columnar cells are numerous and long, with the apical portion showing many lengthy microvilli and the basal portion invaginations forming a basal labyrinth. The goblet cells have a large goblet-shaped central cavity delimited by cytoplasmic projections filled with mitochondria. The regenerative cells present electron-dense cytoplasm and few organelles. The endocrine cells are characterized by electron-dense secretory granules, usually concentrated in the cytoplasm basal region.

scholarly journals Immunocytochemical localization of cathepsin B in rat anterior pituitary endocrine cells, with special reference to its co-localization with renin and prorenin in gonadotrophs.

1991 ◽  
Vol 39 (9) ◽  
pp. 1199-1205 ◽  
Author(s):  
Y Uchiyama ◽  
M Nakajima ◽  
T Watanabe ◽  
S Waguri ◽  
N Sato ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Luteinizing Hormone ◽  
Light Microscopy ◽  
Cathepsin B ◽  
Anterior Pituitary ◽  
Endocrine Cells ◽  
Secretory Granules ◽  
Juxtaglomerular Cells ◽  
Immunocytochemical Localization ◽  
Double Immunostaining

We examined by immunocytochemistry the localization of cathepsin B in endocrine cells of rat anterior pituitary lobe, using a monospecific antibody to cathepsin B. By light microscopy, granular immunodeposits for cathepsin B were detected in most endocrine cells of anterior pituitary lobe. Cells immunoreactive for luteinizing hormone (LH) were diffusely immunostained by anti-cathepsin B. By electron microscopy, immunogold particles for cathepsin B were localized in lysosomes of thyrotrophs, somatotrophs, and mammotrophs. In mammotrophs, immunogold particles for cathepsin B were also detected in crinophagic bodies. Double immunostaining co-localized immunogold particles for LH and cathepsin B in secretory granules of gonadotrophs. Immunocytochemistry was also applied to demonstrate localization of renin and prorenin in LH-producing gonadotrophs; immunogold particles for renin were co-localized with those for LH, cathepsin B, or prorenin in their secretory granules. Immunogold particles for prorenin were also co-localized with those for LH or cathepsin B in secretory granules, but prorenin-positive granules appeared less frequently than renin-positive granules. These results suggest that cathepsin B not only plays a role in the protein degradation in lysosomes of anterior pituitary endocrine cells but also participates in the activation of renin in gonadotrophs, as has been demonstrated in secretory granules of juxtaglomerular cells.

scholarly journals Immunocytochemical Localization of Prohormone Convertases PC1 and PC2 in the Mouse Thyroid Gland and Respiratory Tract

2002 ◽  
Vol 50 (7) ◽  
pp. 903-909 ◽  
Author(s):  
Shingo Kurabuchi ◽  
Shigeyasu Tanaka
Keyword(s):  
Electron Microscopy ◽  
Thyroid Gland ◽  
Respiratory Tract ◽  
Secretory Granules ◽  
Light And Electron Microscopy ◽  
Neuroendocrine Cells ◽  
Immunogold Electron Microscopy ◽  
Immunocytochemical Localization ◽  
Prohormone Convertases ◽  
Parafollicular Cells

We examined immunocytochemical localization of the prohormone convertases, PC1 and PC2, in the thyroid gland and respiratory tract of the adult mouse using the indirect enzyme- and immunogold-labeled antibody methods for light and electron microscopy, respectively. In the thyroid gland, PC1- and/or PC2-immunoreactive cells were cuboidal, scattered in the follicular epithelium and in the interfollicular spaces. When serial sections were immunostained with anti-calcitonin, anti-PC1, anti-calcitonin-gene-related-peptide (CGRP), and anti-PC2 sera, respectively, localization of both PC1 and PC2 was restricted to the calcitonin/CGRP-producing parafollicular cells. In the respiratory tract, only PC1 immunoreactivity was observed in the basal granulated neuroendocrine cells, which were scattered in the tracheal epithelium. Consecutive sections immunostained with anti-PC1 and anti-CGRP sera showed that a subpopulation of these PC1-immunoreactive cells contained CGRP. Double immunogold electron microscopy of the thyroid parafollicular cells revealed that calcitonin- and/or CGRP-immunopositive secretory granules were also labeled with both PC1 and PC2. These findings suggest that procalcitonin is proteolytically cleaved by PC2 alone or by PC2 together with PC1, and that the proCGRP is cleaved by PC1.

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