bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Streptozotocin and Alloxan on Granular Tubules of Male Mouse Submandibular Gland
Authors: deCamargo A. M. , Hanker J.S. , Ambrose W.W. , Hilton WF. , Giammara B.L. 
Published: June 2020

Diabetogenic agents can be conveniently classified into simple chemicals and complex hormones. Streptozotocin and alloxan are diabetogenic chemicals which cause a permanent diabetes by destruction of the B cells of the islets of Langerhans of the pancreas and a resulting insulin deficiency. The diabetogenic chemicals, however, may also have sex hormone-like actions which could be contributory or even causative factors in diabetes mellitus.Circulating androgens have long been known to effect a sexual dimorphism of the submandibular gland,and spontaneous diabetes markedly affects the development of the submandibular glands of mice. The effects of alloxan on the submandibular gland of male mice has previously been reported.In the present study, the effects of streptozotocin, a diabetogenic agent widely employed in cancer chemotherapy, were investigated in heterozygous male mice of the C57BI, Ksj db strain whose homozygous littermates are afflicted with a syndrome resembling maturity-onset human diabetes mellitus.
The Three-Dimensional Organization of the Arsenic Inclusion Using HVEM
Authors: Sorense E. M. B. , Mitchell R. R. 
Published: June 2020

The arsenic inclusion is an electron-dense, non-membrane delimited, apparently amorphous structure which appears in the nucleus and cytoplasm of green sunfish (Lepomis cyanellus) exposed to 30 or 60 ppm arsenic, as sodium arsenate, dissolved in water. The intranuclear and cytoplasmic inclusions first appear in cells within one week and, over a period of several weeks, increase in size and number regardless of the location within the hepatocyte. Subfractionation data indicates that, within 6 days, arsenic is mobilized from a predominantly cytoplasmic to a predominantly nuclear location, and recent electron probe X-ray microanalysis data confirms the presence of arsenic within the inclusion. This work was conducted to obtain additional morphological data for comparison of this inclusion with the intranuclear lead inclusion and the intranuclear selenium inclusion.Green sunfish were exposed to 60 ppm arsenic for varying time intervals prior to sacrifice. Livers were rapidly removed and cubed for fixation in buffered 3% gluteraldehyde prior to post-fixation in 2% buffered osmium tetroxide, rinsing in buffer, then water, en bloc staining with uranyl acetate, dehydration, and embedding in Araldite Epon.
Analysis of the Anterior Secretory Cells of Onchidohs Muricata (Nudibranchia)
Authors: Skidmore Roy 
Published: June 2020

The long-necked secretory cells in Onchidoris muricata are distributed in the anterior sole of the foot. These cells are interspersed among ciliated columnar and conical cells as well as short-necked secretory gland cells. The long-necked cells contribute a significant amount of mucoid materials to the slime on which the nudibranch travels. The body of these cells is found in the subepidermal tissues. A long process extends across the basal lamina and in between cells of the epidermis to the surface of the foot. The secretory granules travel along the process and their contents are expelled by exocytosis at the foot surface.The contents of the cell body include the nucleus, some endoplasmic reticulum, and an extensive Golgi body with large numbers of secretory vesicles (Fig. 1). The secretory vesicles are membrane bound and contain a fibrillar matrix. At high magnification the similarity of the contents in the Golgi saccules and the secretory vesicles becomes apparent (Fig. 2).
Ultrastructure of Hepatic Glycogen and Smooth Endoplasmic Reticulum in Rats Treated with Compound 48/80
Authors: Dimlich R. V. W. , Cardell R. R. 
Published: June 2020

While investigating the mast cell population in the liver of the rat, compound 48/80, a mast cell degranulating agent caused a significant increase in blood-glucose. Subsequent biochemical and histochemical analyses of hepatic tissue indicated that there was a decrease in hepatic glycogen. Since the degradation of glycogen has been associated with an increase in the amount of smooth endoplasmic reticulum (SER), we have initiated a study with the objective of evaluating the changes in form and amount of SER in hepatocytes from animals treated with 48/80.Ten male Sprague-Dawley rats were anesthetized by injections (ip) of urethane (2 mg/g) and subsequently injected (iv) with 48/80 (50 ug/kg) or an equivalent volume (0.5 ml/100 g) of Ringer's solution as a control.Thirty minutes later, hepatic tissue was removed and fixed in 2% glutaral- dehyde and 2% paraformaldehyde in a 0.1 M Na cacodylate buffer (pH 7.3), postfixed in phosphate buffered 1% osmium tetroxide, and embedded in Epon.
Plastid Development in Leaf Epidermis
Authors: Varkey Jacob P. , Nadakavukaren Mathew J. 
Published: June 2020

Changes in the plastid ultrastructure during development of a leaf have been studied extensively. Most studies have been done on the development of chloroplasts in mesophyll cells. Chloroplasts are small and few in number or plastids never develop into chloroplasts in epidermal cells of leaves of many species. Not much is known about the development of plastids in the epidermal tissue. Sunflower was selected to study the plastid development in the epidermal tissue.Sunflower plants were grown from seeds in growth chambers maintained on a 14:10 light:dark cycle at a daytime temperature of 78 F and nighttime temperature of 70 F with 80% humidity. Samples for ultrastructural study were taken from primary leaves at different stages of development. Because the rate of leaf development can vary from plant to plant, samples were taken from the same primary leaves of selected seedlings. These samples fixed in glutaraldehyde followed by osmium tetroxide were processed for electron microscopy using standard procedures.
High-Voltage Electron Microscopy (HVEM) of Pineal Gland Cell Cultures
Authors: Turner J. N. , Shain W. G. , Parfitt A. G. 
Published: June 2020

Light and high-voltage electron microscopy are used to observe cell cultures nrenared from neonatal rat pineal glands. The light microscopy provides identification of pinealocytes from the background cells by morphological criteria (Parfitt et al., in preparation). Due to its penetrating power and depth of field the HVFM images both cell layers at high resolution.Cultures are prepared from pineal glands of 3-day-old rats by decapsulation, dissociation in chick serum, trypsin and collagenase, and tituration. Cells are plated on Formvar-carbon-coated gold grids in modified Ham's F-12 medium with 10% fetal bovine serum and fed every third day with serum-free F-12 medium, with synthetic medium N1 supplements. After 10-14 days the cultures are fixed in 2% gluteraldehyde in cacodylate buffer, postfixed in 1% OsO4, photographed in the light microscope, dehydrated in ethanol, and critical-point-dried from CO2.
Quantitative Studies of Nuclear Polyhedrosis Virus Produced In Vitro
Authors: Smith G. C. , Weiss S. A. , Kalter S. S. , Vaughn J. L. 
Published: June 2020

In initial studies, replication of Autographa californica nuclear polyhedrosis virus (large volume production) in Spodoptera frugiperda (IPL/SF-21AE111) insect cell line in the presence of ALCL3 and/or ZnSO4 7 H2O was considerably enhanced when determined by a variety of methods including the electron microscopic (EM) techniques reported herein. Optimization of viral growth, thereby reducing costs, is an important parameter in production of viruses as an alternative to chemical pesticides.EM quantitation and morphometric analysis of virus particles (VP) or polyhedral inclusion bodies (PIB) was based on application of a thin section technique involving the sedimentation of subcellular particles onto a Millipore filter. The equation:was used to calculate both VP or PIB/unit volume. Accordingly where D is the diameter (4 mm) of the filter and A is the average number of VP or PIB counted in fields of length (L) and thickness (T1). The equation: T1 = T + Dv - 2 f Dv was used to determine the effective section thickness (T1).
Direct Visualization of Uranyl Stain Crystallization on a Biological Specimen During Electron Irradiation
Authors: Kunath W. , Lamvik M. 
Published: June 2020

Electron diffraction patterns from thin films of uranyl acetate (Uac) stain show that with increasing electron dose there is a narrowing of the initially broad and diffuse ring of intensity due to the stain, indicating that the stain becomes microcrystalline. The sharp intensity rings observed at higher dose have been identified as UO2 crystals. Here we report on direct visualization of the formation of 3 Å lattice fringes in the Uac stain during irradiation. The stain was used to produce negatively and positively contrasted tetramers of 80S ribosomes.The three images of negatively stained ribosome tetramers in Fig. la are part of a dose series taken at 200,000x. The focus is corresponding to minimum phase contrast. The first image was exposed to a dose of 400 e/Å2, while the second and third images were exposed to 3 and 100 times more dose, respectively. Locally high contrast regions smaller than 10 Å can be seen in any of the micrographs, but their appearance deteriorates in the subsequent micrograph of the series, indicating considerable atomic mobility.
Observations of the Golgi Apparatus in Pisum Primary Roots
Authors: Spink Gordon C. 
Published: June 2020

It is known that the product of the Golgi apparatus vesicles is deposited at and localized in the cell wall. This is accomplished by the formation of the hypertrophied dictyosomes and the subsequent movement of these vesicles to the plasma membrane (Fig. 1). After fusion with the plasma membrane, the secreted material is released into the cell wall area and, in some plants under appropriate conditions, moves outward through the cell wall and appears as a droplet on the root tip.In primary roots of Pisum sativum, var. Alaska (common garden pea) the Golgi apparatus vesicle product accumulates between the plasma membrane and the cell wall, particularly in those cells at the extreme tip of the root. These cells are formed at the acropetal end of the columella cells.
Electron Microscopic Examination of a Transplantable Rat Mammary Carcinoma
Authors: Shirahama S. , Engle G. C. , Dutcher R. M. 
Published: June 2020

A transplantable carcinoma was established in North West Sprague Dawley (NWSD) rats by use of X-irradiation by Engle and Spencer. The tumor was passaged through 63 generations over a period of 32 months. The original tumor, an adenocarcinoma, changed into an undifferentiated carcinoma following the 19th transplant. The tumor grew well in NWSD rats of either sex at various ages. It was invariably fatal, causing death of the host within 15 to 35 days following transplantation.Tumor, thymus, spleen, and plasma from 7 rats receiving transplants of tumor at 3 to 9 weeks of age were examined with an electron microscope at intervals of 8, 15, 22 and 30 days after transplantation. Four normal control rats of the same age were also examined. The tissues were fixed in glutaraldehyde, postfixed in osmium tetroxide and embedded in Epon. The plasma was separated from heparanized blood and processed as previously described for the tissue specimens. Sections were stained with uranyl acetate followed by lead citrate and examined with an RCA EMU-3G electron microscope.
Electron Microscopy of California Isolate of Cat Leukemia Virus
Authors: Kawakami T. G. , Theilen G. H. , Munn R. J. 
Published: June 2020

Although “C”-type viral particles have been observed in oats with feline leukemia, the developmental stages, morphological characteristics and sites of replication have not been fully described. The isolation of an agent from a cat with spontaneous leukemia and transmission of the disease with cell-free preparations to newborn kittens presented an opportunity for an extensive eleotron mioroscopic examination of the feline leukemogenic agent.The agent apparently undergoes development by budding from the plasma or vacuolar membranes of infected host cells. The earliest stage of development is recognizable in thin section by a crescent-shaped electron-dense zone beneath the plasma membrane (Fig. 1a). This structure or bud enlarges progressively into a sphere which is resolvable into two concentric components and concomitantly causes a protrusion of the plasma membrane. Later stages are independent of the host cell proper. The immature forms (Fig. 1b), one recently detached from the plasma membrane, still maintain the internal morphology of the later stages of budding but is completely surrounded by a protein coat. The mature forms (Fig. 2) which develop by reorganization of the dense shells possess either a central electron-dense or central electron-lucent nucleoid. The difference between mature electron-lucent and immature forms appears to be an absence of the organized concentric shell in the former.
A Micro-diffusion Technique for Visualizing Nucleic Acid Molecules
Authors: Mayor H. D. , Jordan L. E. 
Published: June 2020

Contour lengths, molecular weights, and topological parameters of single molecules of nucleic acids can be studied accurately by electron microscopy. However, specialized equipment and highly purified samples of DNA or RNA in an amount of 10-100 μgm have been required. We have developed a simple micro-diffusion technique which uses less than 0.01 (μgm of nucleic acid. Droplets containing the nucleic acid are placed on a clean teflon sheet. Cytochrome C powder is added by needle to form a monofilm. After 20-30 minutes diffusion time, there is usually enough material attached for the film to be picked up on a suitable specimen grid, shadow-cast or stained, and examined in the electron microscope. Each droplet provides material for a single observation, but experiments may be carried out contiguously on the sheet.The method has been developed for viral nucleic acids, but can also be applied to solutions of virus particles where the genomes can be released by osmotic shock or by other physical procedures. Less than 1010 particles per ml are required for this modification. Examples of nucleic acids liberated from papovaviruses, SV40, rabbit papilloma, human papilloma, and from adeno-associated satellite virus will be presented. Viral nucleic acids (DNAs from SV40 and adenovirus, RNA from bacteriophage R17) prepared by conventional techniques will also be shown.
Epoxy Resin Embedment
Authors: Adams J. G. , Campbell M. M. , Thomas H. , Ghldonl J. J. 
Published: June 2020

Since the introduction of epoxy resins as embedding material for electron microscopy, the list of new formulations and variations of widely accepted mixtures has grown rapidly. Described here is a resin system utilizing Maraglas 655, Dow D.E.R. 732, DDSA, and BDMA, which is a variation of the mixtures of Lockwood and Erlandson. In the development of the mixture, the Maraglas and the Dow resins were tested in 3 different volumetric proportions, 6:4, 7:3, and 8:2. Cutting qualities and characteristics of stability in the electron beam and image contrast were evaluated for these epoxy mixtures with anhydride (DDSA) to epoxy ratios of 0.4, 0.55, and 0.7. Each mixture was polymerized overnight at 60°C with 2% and 3% BDMA.Although the differences among the test resins were slight in terms of cutting ease, general tissue preservation, and stability in the beam, the 7:3 Maraglas to D.E.R. 732 ratio at an anhydride to epoxy ratio of 0.55 polymerized with 3% BDMA proved to be most consistent. The resulting plastic is relatively hard and somewhat brittle which necessitates trimming and facing the block slowly and cautiously to avoid chipping. Sections up to about 2 microns in thickness can be cut and stained with any of several light microscope stains and excellent quality light photomicrographs can be taken of such sections (Fig. 1).
Schwann Cell Reactions in Acute and Chronic Segmental Demyelinating Neuropathies
Authors: Weller Roy O. 
Published: June 2020

The length of axon that each Schwann cell myelinates in a normal peripheral nerve is approximately proportional to the diameter of the axon and the thickness of the myelin sheath produced. When segmental demyelination occurs, individual segments, represented by the length of axon covered by one Schwann cell, lose their myelin sheaths but the axons are preserved. This differs from Wallerian degeneration where myelin destruction occurs along the length of a nerve fibre following death of the axon.In experimental diphtheritic neuropathy, an acute segmental demyelinating disease, lysosomes accumulate within the Schwann cells prior to disruption of the myelin sheath; furthermore, the site of initial myelin breakdown appears to be closely related to the collections of lysosomes. The Schwann cell starts to form a new myelin sheath around the axon probably within a few hours of the destruction of the original myelin sheath, and while the latter is being catabolised within lysosomal vacuoles This stage of remyelination follows a similar course to primary myelination, so that the recovery stage is characterised by normal axons with either no myelin, or surrounded by sheaths that are very thin relative to the diameter of the axon.
Octagonal Pores in Annulate Lamellae of Rana Pipiens Oocytes
Authors: Kessel R. G. 
Published: June 2020

Negative staining of isolated nuclear envelopes by phosphotungstate in several amphibian oocytes by Gall has shown the pores to be octagonal rather than circular in shape and, further, that the outer and inner diameters of the annulus associated with each pore are respectively greater and less than the width of the pore itself.Electron microscope studies on thin sections of glutaraldehydeosmium tetroxide fixed oocytes of Rana pipiens have revealed evidence that pores in the annulate lamellae are also octagonal in shape. Tangential sections of the annulate lamellae illustrating several pore-annulus complexes are illustrated in Figs. 1-4. That the pores possess octagonal symmetry is reasonably clear from direct inspection of the micrographs. In Fig. 2 the most apparent sides defining the octagon are indicated by the inked lines. The distance between two opposite sides of the octagon (i.e., the inner width of the octagon) is approximately 700 Å. The center to center spacing of the pores is approximately 125 mμ.
Ultrastructural Observations of the Rat Oocyte During the Estrous Cycle
Authors: Baccarini I. M. 
Published: June 2020

The cytological ultrastructure of the oocyte in different vertebrates and in insects has been described. Additional information on this subject is the purpose of this report which describes the findings on the oocyte of the rat during the estrous cycle.Vaginal smears were taken daily from 27 inbred Wistar-Furth rats to determine stages of the cycle. The animals were sacrificed with anesthesia in proestrous, estrous and metestrous and the ovaries removed surgically. In each case one ovary was used for electron microscopy and the other for histochemical methods.The ovary for electron microscopy was placed immediately into cold 3% phosphate-buffered glutaraldehyde for 2 hours and then into 1% phosphate-buffered osmic acid for 2-3 hours. The tissue was embedded in Durcupan ACM (FLUKA). The sections were double stained with 50% alcoholic uranyl acetate solution and with lead citrate.
Fine Structure of the Normal Canine Prostate
Authors: Maser M. D 
Published: June 2020

The secretory epithelia of prostate glands of healthy dogs have varieties of organization and subcellular structure that previously have not been reported. In some acini, the secretory cells are columnar, and are aligned in a single layer (Fig. 1). The cells are of two types, “light” and “dark”, which I have been able to distinguish only on the basis of general cytoplasmic density. Other structural features of interest are: extensive lateral intercellular interdigitation; irregularly shaped, large lipid bodies, often associated with high concentrations of glycogen, and present in both the apical and basal regions of the cells; apically concentrated secretory granules, some of which are distinguished by having dense cores; prominent Golgi apparatuses, oriented both apically and laterally; extensive rough endoplasmic reticulum, some cisternae of which are distended; and nuclei which are often observed to be multi-lobular and very irregular in outline. Cells arranged in this manner have well defined tight junction complexes at their lateral apical surfaces.In most acini, however, the architecture is more complicated. Often, thin extensions of dark cell cytoplasm surround and separate adjacent light cells (Fig. 2). The dark cell cytoplasm is expanded in some areas to accomodate mitochondria, and it contains numerous ribosomal clusters and rough endoplasmic reticular cisternae. Desmosomal attachments between the light and dark cells are found commonly in the regions of envelopment. I have not yet determined whether the dark cells completely encapsulate the dark cells in three dimensions.
Ulcerogenic Tumors of the Pancreas
Authors: Garancis J. C. , Kuzma J. F. , Wilson S. D. , Ellison E. H. 
Published: June 2020

It has been proposed that a gastrin-like hormone elaborated by non-beta islet tumors of the pancreas may be responsible for a fulminating ulcer diathesis. Subsequently, a potent gastric secretagogue was isolated from ulcerogenic tumors of the pancreas. This disease process is known now as “Zollinger-Ellison syndrome”.In our studies of two cases of Zollinger-Ellison syndrome, pancreatic lesions were identified as alpha islet cell tumors (Fig. 1). Tumor cells were fairly uniform. The sizes of the alpha granules were not significantly different, but their number and distribution varied greatly from one cell to another. Each granule consisted of a round, highly dense central core, separated from the limiting membrane by an opaque zone. The granular form of the endoplasmic reticulum was particularly prominent. Numerous mitochondria, round or elongated, were dispersed throughout the cytoplasm. Individual or clusters of lysosomes were observed in the majority of cells.
Electron Microscopic Observations On An Amphibian Polyhedral Virus (LT-1) Propagated in Vitro in Reptilian Cells
Authors: Zeigel R.F. , Clark H .F. , Karzon D. T. 
Published: June 2020

Polyhedral, cytoplasmically derived, viral agents have been isolated from Rana pipiens and characterized in baby hamster kidney and Fathead minnow cells in vitro. These viruses are not similar to the Herpes-type virus associated with the Lucké tumor in these frogs. Clark, et al have recently described additional isolates of similar polyhedral agents from the leopard frog after passage through red efts (Triturus viridescens). This virus series, designated LT-1, -2, -3, -4, has been propagated in the turtle heart cell line TH-1. This report presents morphological studies on these isolates.Slow speed centrifuged cell packs were fixed in cold chrome-osmium (Dalton) followed by fixation in cold 0.5% aqueous uranyl-acetate with 0.54% sucrose. Sections were double stained with uranyl-acetate and lead citrate.The virus particles were observed to form in juxta-nuclear viroplasmic regions within the cell cytoplasm. Evidence of intranuclear virus synthesis has not been observed, to date. Viroplasmic regions were frequently surrounded by mitochondria. Within the viroplasmic regions the fixation used preserved a filamentous mesh work which is observed to be continuous with that which is accumulated inside the virions (Figs. 1, 2). This filamentous material is similar to that observed in Mycoplasma and in poxvirus viroplasm.