Showing papers in "Journal of Ultrastructure Research in 1971"

TL;DR: Preliminary observations on RNA polymerase attached to DNA suggest that the internal structures of the protein may be observed and that the enzyme is probably attached asymmetrically to the DNA.

TL;DR: Reciprocity of specimen lifetime and current density at the specimen demonstrates the absence of any dose-rate effect, such as specimen heating, as a cause of specimen damage within the range 10−3 to 10−5 amperes/cm2 current densityat the specimen.

TL;DR: Results are presented which indicate that the DMSO-trialdehyde combination followed by postosmication has application to other embryonic organisms in addition to amphibians.

TL;DR: Sensory cells in the pigeon's basilar papilla can be divided into three groups on the basis of shape, cuticular plate dimensions, and innervation.

TL;DR: Renewal of the photosensitive outer segment of rod visual cells involves the continued assembly of new membranous discs accompanied by a balanced loss and destruction of old disc material.

TL;DR: It is proposed that this represents the elaboration and release of corticosteroid hormones by a modified apocrine secretion which the authors would term endoplasmocrine secretion for the purposes of satisfactorily distinguishing it from other modes of endocrine and exocrine secretion.

TL;DR: The results of this study suggest that the viral envelope is lost at, or during, the entry process since only nonenveloped nucleocapsids were seen in cells shortly after infection, and it is suggested that virus progeny are released into the insect hemocoel by such processes.

TL;DR: The nature of the milk fat globule membrane (MFGM) is shown to depend upon the length of time since the globule was secreted, leaving a structureless secondary MFGM as the only continuous boundary to the milkfat globule.

TL;DR: Enamel deposition begins when a complete layer of calcified dentin is present and large droplets of extracellular material appear at the apex of ameloblasts in preparation for the formation of Tomes' processes.

TL;DR: The results are compatible with the conclusion of earlier studies that hemosiderin may consist largely of ferritin ironcores, which have aggregated on removal of their protein coats by proteolytic digestion.

TL;DR: Perichromatin granules of rat liver cells and ovocyte nuclei and Balbiani ring granules have been compared and it is concluded that both components have similar fine structural and cytochemical properties.

TL;DR: The findings suggest (a) that the process of autophagy is discriminative with respect to the rough surfaced endoplasmic reticulum and triggered by functional and/or structural modifications of this organelle; (b) that hormonal factors, indirectly, exert control over the autophagic process.

TL;DR: The structure of horny cells and their spatial relationship in the stratum corneum of several mammals, including man, have been studied by the combined use of Nomarski differential interference microscopy, transmission electron microscope, and scanning electron microscopy.

TL;DR: Rat submaxillary glands were ligated for 31 days and then the ligatures were removed and there is a pronounced morphologic similarity of glands ligations to immature glands of neonatal rats, however, evidence of parenchymal cell death or mitotic activity is extremely rare and therefore gland recovery is the result of cell recovery, not of de novo cell differentiation.

TL;DR: The results provide suggestive evidence that actin and myosin mainly occur in the circulating platelet in monomeric form, and that physiological activation and unphysiologic treatments as osmotic shock and glycerination cause the formation of filamentous polymers.

TL;DR: The recovery of secretory activity by acinar cells was studied in rat submaxillary glands after the removal of ligatures following 31 days of obstruction, indicating that the observed changes occur in the original cell population and that recovery is not dependent on de novo cell differentiation.

TL;DR: HeLa cells exposed to environmental temperatures higher than the usual 37°C undergo marked morphological and biochemical changes which are reversible after return to normal temperatures, and cell recovery from exposure to 2 hours at 43°C was complete within 24 hours.

TL;DR: The fine structural features of the intraepithelial lymphocytes in the human small intestine include an often irregular outline, sparse cytoplasmic organelles and a compact nucleus.

TL;DR: The results provide further evidence in support of the hypothesis suggested by Descarries and Droz : a nonvesicular binding material or macromolecular complex is present throughout the perikaryon and processes of the catecholaminergic neurons.

TL;DR: In this paper, a long-term tracer (Thorotrast) is injected into the skin of guinea pig epidermis and the tracer penetrates the basal lamina and permeates the intercellular compartment.

TL;DR: The four pairs of eyes in two species of jumping spiders were studied by light and electron microscopy and unique features of the anteromedial eyes, used in acute vision, were identified.

TL;DR: The oocyte of the spider crab Libinia emarginata possesses a two-layered envelope that forms in the ovary between the oocyte and its surrounding follicle cells.

TL;DR: The present paper concerns the organization of the epithelium in three histologically different parts of the midgut, each possibly having a specific function in the process of digestion, and investigates the relationship between these characteristics and functional specializations.

TL;DR: The observed structural arrangement of the diaphragm or central density of the pores may account for the "small pores" required by the “pore theory" of capillary permeability and for rapid passage of peroxidase molecules, but a purely structural function cannot be excluded.

TL;DR: The findings and conclusions of this study correlate well with information derived from “whole mounts” of native fibrils, studied by negative stains, and by other means.

TL;DR: The ultrastructure of early passage, rapidly dividing cells was compared with that of late passage cells showing a reduced proliferation rate and degeneration, and the most striking change was the presence of conspicuous secondary lysosomes and residual bodies in over 90% of the late passge cells.

TL;DR: In this article, the Feinstruktur der Muskel-Sehnenverbindung in Zunge, Papillarmuskel, M. gastrocnemius and Zwerchfell von Meerschweinchen wurde im Elektronenmikroskop untersucht.

TL;DR: It appeared that the homogeneous matrix in which the melanin was eventually produced did not arise from blood cells, but from components in the noncellular portion of the hemolymph that coagulated out on the surface of the nematode.

TL;DR: Specialized epidermal cells, termed Merkel cells, have been revealed in electron microscope observations of developing epidermis of sheep fetuses, ranging in age from 57 to 144 days gestation, and the innervation of these specialized cells was less than that of Merkel cells ofEpidermal pads in other species.

TL;DR: The cell bodies of the postganglionic neurons in the inferior mesenteric ganglion of the cat have a variable number of short narrow processes —accessory dendrites—which usually contain very dense-core vesicles, about 200–500 A in diameter.