Fine structure of crystalline inclusions in B-cells of the islets of Langerhans in the alligator

1978 ◽  
Vol 187 (3) ◽  
pp. 535-550 ◽  
Author(s):  
I. Raška ◽  
J. Komrska ◽  
M. Titlbach ◽  
M. Rieder
Keyword(s):  
Fine Structure ◽  
B Cells ◽  
Islets Of Langerhans ◽  
Crystalline Inclusions

scholarly journals CYTOCHEMICAL LOCALIZATION OF ADENYL CYCLASE ACTIVITY IN RAT ISLETS OF LANGERHANS

1972 ◽  
Vol 20 (11) ◽  
pp. 873-879 ◽  
Author(s):  
S. L. HOWELL ◽  
MARGARET WHITFIELD
Keyword(s):  
B Cells ◽  
Islets Of Langerhans ◽  
Adenosine Triphosphate ◽  
Adenyl Cyclase ◽  
Cyclase Activity ◽  
Cytochemical Localization ◽  
Adenyl Cyclase Activity ◽  
Rat Islets ◽  
Rat Islets Of Langerhans ◽  
A And B Cells

A cytochemical method has been used to investigate the localization of adenyl cyclase activity in A and B cells of isolated rat islets of Langerhans. Adenosine triphosphate was initially utilized as substrate, the pyrophosphate liberated being precipitated by lead ions at its site of production. The specificity of the method was increased by the use of adenylyl-imidodiphosphate as an alternative substrate; this adenosine triphosphate analogue was not hydrolyzed by adenosine triphosphatase but provided an effective substrate for adenyl cyclase. Adenyl cyclase activity, which was found to retain its glucagon and fluoride sensitivity in glutaraldehyde-fixed tissue, was found exclusively and almost uniformly in the plasma membranes of A and B cells. Storage granule membrane, incorporated into the plasma membrane during secretion of the granule content by exocytosis, appeared to be devoid of adenyl cyclase activity.

Hyperplasia and hypertrophy of B cells in the islets of Langerhans in hamsters infected with the 139H strain of scrapie

1994 ◽  
Vol 110 (2) ◽  
pp. 169-183 ◽  
Author(s):  
X. Ye ◽  
R.I. Carp ◽  
Y. Yu ◽  
R. Kozielski ◽  
P. Kozlowski
Keyword(s):  
B Cells ◽  
Islets Of Langerhans

Mitotic E- and Secretory F-Cells in the Hepatopancreas of the Shrimp Penaeus Semisulcatus (Crustacea: Decapoda)

1985 ◽  
Vol 65 (4) ◽  
pp. 901-910 ◽  
Author(s):  
S. Y. Al-Mohanna ◽  
J. A. Nott ◽  
D. J. W. Lane
Keyword(s):  
Fine Structure ◽  
B Cells ◽  
Hydrolytic Enzymes ◽  
M Cells ◽  
Secretion Granules ◽  
Penaeus Semisulcatus ◽  
Feeding Cycle ◽  
F Cells ◽  
The Subject ◽  
Experimental Treatments

INTRODUCTIONIt is apparent, in a review on the decapod hepatopancreas (Gibson & Barker, 1979) that there is some consensus of opinion that the epithelium consists of E-, R-, F- and B-cells and M-cells (Al-Mohanna, Nott & Lane, 1985). Also, it is agreed that the gland produces enzymes and absorbs, digests and stores nutrients and excretes waste material. However, the apportionment of these functions to the different cells and the descriptions of the cytological processes involved are variously explained. Thus, the activity of proteases and amylases has been demonstrated in the secretion produced by the gland but the source of these enzymes is attributed to different cells and various modes of secretion are proposed. Also, no secretion granules of the zymogen type have been seen.There are probably two main reasons for the inconsistent interpretation of the activities of the cells. First, the different stages of the feeding and moult cycles are not taken into account and both these affect the cytology of the gland. Second, some of the functions have been deduced from observations of the fine structure without any experimental treatments to demonstrate more directly the processes involved. In the present work all the animals are taken at the same moult stage and observations are made throughout the feeding cycle. Also, aspects of the function are studied with markers which are administered in the diet and injected into the blood. The activities of hydrolytic enzymes associated with the different epithelial cells have been studied but these will be the subject of a separate publication dealing with the cytochemistry of the digestive processes.

A FLUORESCENT REACTION FOR MONOAMINES IN THE INSULIN PRODUCING CELLS OF THE GUINEA-PIG

1964 ◽  
Vol 45 (1) ◽  
pp. 133-138 ◽  
Author(s):  
Bengt Falck ◽  
Bo Hellman
Keyword(s):  
B Cells ◽  
Islets Of Langerhans ◽  
Silver Impregnation ◽  
Fluorescent Light ◽  
Storage Site ◽  
Insulin Producing Cells ◽  
Freeze Dried ◽  
Aldehyde Fuchsin ◽  
Fluorescent Products ◽  
Fluorescent Cells

ABSTRACT Certain catecholamines and tryptamines condense in freeze-dried tissues with formaldehyde to form intensely fluorescent products. A distinct fluorescence has recently been demonstrated in the islets of Langerhans from several species with this sensitive and specific technique. The fluorescent reaction of the islets has been studied in more detail in the guineapig. Using a combination of fluorescence microscopy with subsequent silver impregnation and granule staining on the same section it was found that the fluorescent cells were identical with the B cells. The B cells exhibited no, or only weak, fluorescence after administration of reserpine. The colour of the emitted fluorescent light suggests that the B cells contain a tryptamine rather than a catecholamine. Since the fluorescent material was distributed in fine cytoplasmic granules the amine may be associated with the aldehyde-fuchsin positive granules which are regarded as the storage site for insulin or some insulin precursor. No support was found for the previous concept of an adrenergic parenchymatous innervation of the islets of Langerhans.

Cryo-Ultramicrotomy of Islets of Langerhans

1974 ◽  
Vol 15 (3) ◽  
pp. 591-603
Author(s):  
S. L. HOWELL ◽  
MARGARET TYHURST
Keyword(s):  
Polyethylene Glycol ◽  
B Cells ◽  
Islets Of Langerhans ◽  
Structural Features ◽  
Silicotungstic Acid ◽  
Frozen Sections ◽  
Glutaraldehyde Fixation ◽  
Ultrathin Frozen Sections ◽  
Direct Immersion ◽  
A And B Cells

A procedure is described for the preparation of ultrathin frozen sections of glutaraldehyde-fixed or unfixed islets of Langerhans by cryo-ultramicrotomy. Freezing of the tissue was accomplished by direct immersion of isolated islets in liquid nitrogen. Sectioning was performed at a specimen temperature of -80 °C and a knife temperature of -40 °C, the ribbon of sections being collected on a trough containing 60 % dimethyl sulphoxide. Staining was accomplished with 4 % silicotungstic acid and sections were protected from drying artifacts by rinsing with 0.5% polyethylene glycol. Even in tissue not subjected to prior glutaraldehyde fixation, most of the structural features of A and B cells were well preserved in frozen sections, which were obtained in a number and quality which should render them suitable for ultrastructural, cytochemical or radioautographic studies.

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