Annulate lamellae in hepatic and pancreatic beta cells of the chick embryo. 1

Development of the glycogen body of the Japanese quail, Coturnix japonica: II. Observations of electron microscopy

Transmission electron microscopic observations of the relationships of the cells of the glycogen body and those of nervous tissue in the lumbosacral spinal cord show that one day after hatching, glycogen cells at the lateral margins of the glycogen body lie in close association with elements of the neuropil in the adjacent spinal cord. Glycogen cells and their processes appear to extend into the neuropil, where they contact other glycogen cells, blood vessels, neurons, and neuroglia. Junctional complexes and synapses occur among glycogen cells, astrocytes, and oligodendrocytes. Other indications of specialized activities were surmised by the presence of annulate lamellae in continuity with extensive arrays of smooth endoplasmic reticulum in several glycogen cells. These observations enhance our earlier views that cells of the avian glycogen body are metabolically active in the synthesis and degradation of glycogen for neuronal support and myelination in the central nervous system.

Ultrastructure of the normal human placenta

In this review, the ultrastructure of the normal human chorionic villus is examined and illustrated. The outer covering of trophoblast, comprising the generative cytotrophoblast and the multinucleated syncytiotrophoblast which is derived from it, is described, including such features as the microvillous surface, vesicles and vacuoles, endoplasmic reticulum and secretory droplets. The structure, composition, development and inclusions of the trophoblastic basement membrane are discussed, and the ultrastructure of the various components of the stroma, including reticulum cells, fibroblasts, Hofbauer cells, capillaries and the non-cellular matrix are illustrated and described, with special reference to their inter-relationships and function.

The annulate lamellae--from obscurity to spotlight

This review aims to provide a comprehensive and in-depth survey of a cell organelle, the annulate lamellae, that is widely distributed and especially prevalent in both female and male sex cells as well as tumor and cancer cells. The organelle is also present in many somatic cells and plant cells. Emphasis is placed on the contributions that electron microscopy and associated experimental approaches have made in providing information about the distribution, ultrastructure, morphogenesis and relationships of annulate lamellae to other cellular organelles, especially the nuclear envelope and endoplasmic reticulum, as well as cell product. An increasing number of experimental manipulations have recently been shown to alter, either increase or decrease, the amount of annulate lamellae and these studies are explored in depth. Information about the origin and morphogenesis of annulate lamellae in different cells is summarized and extensive coverage is given to several hypotheses about possible annulate lamellae function. A detailed bibliography provides a thorough compilation of research dealing with annulate lamellae. A major goal of this extensive review is to generate increased awareness of, and interest in, this cell organelle for students and investigators of the cell who, by bringing current techniques in cell and molecular biology to bear, might focus and intensify studies on the function of an organelle whose precise role in the cell is presently enigmatic.

Effect of 1.25-dihydroxycholecalciferol administration on blood glucose and pancreatic islet morphology in mice

1.25-dihydroxycholecalciferol (DHCC) administration to fed and starved mice had no effect on the blood-glucose concentration or the light-microscopic appearance of the endocrine or exocrine pancreas. Electron microscopy, however, disclosed changes which appeared early after the injection and were more marked in starved than in fed animals. The B-cells exhibited mitochondrial hypertrophy, studied both by qualitative and quantitative methods, invagination and vacuolation of mitochondrial membranes, increased occurrence of light secretory granules, multiple rough endoplasmic cisternae, multi-lamellar bodies, and a rather rich Ca2+-containing pyroantimonate precipitation mainly localized to nuclei and mitochondria. A tendency to mitochondrial hypertrophy was observed also in some D-cells. The A-cells were unaffected. The findings indicate that the endocrine pancreas (or at least the B-cells) is affected in some way, directly or indirectly, by DHCC.

Annulate lamellae in rete ovarii of juvenile rabbits

Annulate lamellae, though few, were observed in the epithelial cells of rete ovarii of 1-month-old rabbits, but not of other-aged juvenile rabbits examined. There were little differences in the fine structural details between the rete ovarii with annulate lamellae and those without annulate lamellae. Most rete ovarii cells were undergoing atrophy. This finding suggests that annulate lamellae may be quite ordinal, transitory organelles common to virtually all cell types.

Dyserythropoiesis and annulate lamellae

Cytoplasmic and intranuclear annulate lamellae in the erythroblasts from patients with dyserythropoietic anaemia (megaloblastic anaemia, dysplastic anaemia and erythroleukaemia) are described. Annulate lamellae have mainly been observed in oocytes, in embryonic tissues and in malignant cells. Their occurrence in dyserythropoietic anaemia may be related to the reappearance of fetal characteristics in the erythroblasts and erythrocytes.