Quantitative electron microscopic studies on the kinetics of secretory granules in G-cells

Two cases of an unusual type of infiltrating ductal carcinoma of the breast are presented. Both cases demonstrated a carcinoid-like pattern and were indistinguishable from carcinoid tumors of the breast by light microscopy. However, Grimelius stains and electron microscopic evaluation showed no evidence of membrane bound secretory granules. In regard to the prognostic significance and proper classification of carcinoids of the breast, awareness of carcinoid-like morphologic variants of infiltrating ductal or lobular carcinoma is important. It is also apparent that there is a spectrum of tumors which demonstrate some properties of true carcinoids, however, only the true carcinoids show a better prognosis and it serves no useful purpose to separate the rest of these tumors. The diagnosis of carcinoid tumors requires demonstration of secretory granules on electron microscopic examination or in special stains; conventional light microscopic studies alone are insufficient for this diagnosis. All these principles may be applied to carcinoid like tumors of other sites.

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Equations describing the effects of the transient stability of subpopulations of nascent hnRNAs on the kinetics of turnover of hnRNA

Biochemical Journal ◽

10.1042/bj2330905 ◽

1986 ◽

Vol 233 (3) ◽

pp. 905-908

Author(s):

K C Kleene

Keyword(s):

Half Life ◽

Transient Stability ◽

Precise Description ◽

Electron Microscopic ◽

First Order ◽

First Order Kinetics ◽

Microscopic Studies ◽

Rate Of Decay ◽

Kinetics Of ◽

Continuous Labelling

The equations that have been used previously to analyse the rate of decay of hnRNA implicitly assume that nascent hnRNAs are degraded stochastically. This assumption is inconsistent with electron-microscopic studies of transcription cited here, which show that nascent hnRNAs are not degraded during transcription, implying that hnRNA degradation occurs only after termination of transcription and release of the hnRNA from chromatin. Equations are derived describing the accumulation of radioactivity hnRNA during continuous labelling assuming that nascent hnRNAs are stable and that hnRNAs decay with first-order kinetics only after completion of transcription. The effects of the transient stability of nascent hnRNAs on the kinetics of hnRNA turnover can become important when the half-life of the hnRNA is shorter than the time to transcribe an hnRNA from the point of initiation to the point of termination. These equations should prove useful in studies of hnRNA turnover that require a precise description of the labelling kinetics of nascent and completed subpopulations of hnRNA.

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Effect of Nickel and Aluminium on Solid State Transformations in SG Iron

MRS Proceedings ◽

10.1557/proc-34-325 ◽

1984 ◽

Vol 34 ◽

Cited By ~ 2

Author(s):

A. C. Ganguli ◽

A. K. Chakrabarti ◽

S. C. Dasgupta

Keyword(s):

Solid State ◽

Solution Treatment ◽

X Ray Diffraction ◽

Electron Microscopic ◽

X Ray ◽

Temperature Range ◽

Microscopic Studies ◽

Sg Iron ◽

The Individual ◽

Kinetics Of

ABSTRACTThe individual and combined addition of nickel and aluminium to S.g. iron influences several solid state transformations. Nickel depresses the temperature range for reversion of ferrite and pearlite to austenite on heating, while aluminium raises it. Combined addition of nickel and aluminium restores the temperature range closer to that for unalloyed iron. But nickel enhances the kinetics of ferritisation during tempering and weakly retards recrystallisation of ferrite grains. Aluminium strongly retards both the ferritisation and recrystallisation processes. Ferritisation kinetics is enhanced and recrystallisation of ferrite grains is also hastened in alloys containing nickel and aluminium. Alloys containing nickel and aluminium also respond to agehardening treatment in the temperature range 450–550°C after a solution treatment-cum-ferritising anneal at 700°C. On the basis of X-ray diffraction and electron microscopic studies, a probable mechanism of ageing has been proposed.

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Effect of colchicine on the immunohistochemical localization of somatostatin in the rat brain: light and electron microscopic studies.

Journal of Histochemistry & Cytochemistry ◽

10.1177/27.12.391994 ◽

1979 ◽

Vol 27 (12) ◽

pp. 1577-1581 ◽

Cited By ~ 30

Author(s):

D Dubé ◽

G Pelletier

Keyword(s):

Growth Hormone ◽

Rat Brain ◽

Median Eminence ◽

Secretory Granules ◽

Immunohistochemical Localization ◽

Nerve Fibers ◽

Intracerebral Injection ◽

Electron Microscopic ◽

Periventricular Nucleus ◽

Microscopic Studies

Somatostatin (SRIF), the hypothalmic hormone which inhibits the secretion of growth hormone by the pituitary, has been localized immunohistochemically in the rat hypothalamus after intracerebral injection of colchicine. The number of cell bodies staining for SRIF was increased in the periventricular nucleus while the number of nerve fibers was decreased in the median eminence after treatment. The number of secretory granules containing SRIF in the nerve cell bodies was increased in the treated animals, suggesting a correlation between the number of specific secretory granules and intensity of the immunohistochemical reaction. These observations are in agreement with the hypothesis that SRIF cell bodies in the periventricular nucleus send their axons into the median eminence.

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Kinetics of Lymphocytes in Chronic Lymphocytic Leukemia. I. Equilibrium Between Blood and a "Readily Accessible Pool"

Blood ◽

10.1182/blood.v41.3.425.425 ◽

1973 ◽

Vol 41 (3) ◽

pp. 425-438 ◽

Cited By ~ 21

Author(s):

J. Manaster ◽

J. FrÜhling ◽

P. Stryckmans

Keyword(s):

Chronic Lymphocytic Leukemia ◽

Lymphocytic Leukemia ◽

Relative Importance ◽

Electron Microscopic ◽

Blood Lymphocytes ◽

Vascular Space ◽

Vessel Lumen ◽

Microscopic Studies ◽

Kinetics Of ◽

Microscopic Techniques

Abstract Seven patients with chronic lymphocytic leukemia were investigated by isotopic and electron microscopic techniques to study dynamic and morphologic aspects of the kinetics of their lymphocytes. Autotransfusion studies of labeled leukemic lymphocytes showed rapid equilibration of blood lymphocytes between the vascular space and a "readily accessible pool." With increasing absolute blood lymphocytosis (900/cu mm-670,000/ cu mm), the relative importance of the readily accessible pool to the vascular space gradually decreases from eleven to one. Electron microscopic studies of the postcapillary venules in lymph nodes suggest a passage of lymphocytes from the vessel lumen, through the endothelial cells and into extravascular sites. About 20% of lymphocytes counted within the perivascular sheet were found in the wall, irrespective of the blood lymphocytosis and akin to the situation found in hematologically normal persons. These studies indicate that the readily accessible pool is complex and consists of at least two spaces, one of which is the classical recirculation space. The vascular pool of leukemic lymphocytes, as do the blood lymphocytes in hematologically normal persons, participates in this recirculation. There is a second space that has yet to be defined anatomically.

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Electron microscopic studies on ultrathin frozen sections of lactating mouse mammary gland

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081097 ◽

1978 ◽

Vol 36 (2) ◽

pp. 46-47

Author(s):

Jan Zarzycki ◽

Joseph Szroeder

Keyword(s):

Mammary Gland ◽

Protein Denaturation ◽

Chemical Constituents ◽

Freeze Substitution ◽

Electron Microscopic Examination ◽

Mouse Mammary Gland ◽

Electron Microscopic ◽

Preparation Methods ◽

Microscopic Studies ◽

Ultrathin Frozen Sections

The mammary gland ultrastructure in various functional states is the object of our investigations. The material prepared for electron microscopic examination by the conventional chemical methods has several limitations, the most important are the protein denaturation processes and the loss of large amounts of chemical constituents from the cells. In relevance to this,one can't be sure about a degree the observed images are adequate to the realy ultrastructure of a living cell. To avoid the disadvantages of the chemical preparation methods,some autors worked out alternative physical methods based on tissue freezing / freeze-drying, freeze-substitution, freeze-eatching techniqs/; actually the technique of cryoultraraicrotomy,i,e.cutting ultrathin sections from deep frozen specimens is assented as a complete alternative method. According to the limitations of the routine plastic embbeding methods we were interested to analize the mammary gland ultrastructure during lactation by the cryoultramicrotomy method.

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Ultrastructural Aspects of Golgi Complex Function in Parathyroid Cells of Winter Frogs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073842 ◽

1973 ◽

Vol 31 ◽

pp. 680-681

Author(s):

William J. Dougherty

Keyword(s):

Golgi Complex ◽

Secretory Granules ◽

Complex Function ◽

Secretory Activity ◽

Secretory Proteins ◽

Perivascular Spaces ◽

Pituitary Cells ◽

Electron Microscopic ◽

Ca Ions ◽

Regulation Of Secretion

The regulation of secretion in exocrine and endocrine cells has long been of interest. Electron microscopic and other studies have demonstrated that secretory proteins synthesized on ribosomes are transported by the rough ER to the Golgi complex where they are concentrated into secretory granules. During active secretion, secretory granules fuse with the cell membrane, liberating and discharging their contents into the perivascular spaces. When secretory activity is suppressed in anterior pituitary cells, undischarged secretory granules may be degraded by lysosomes. In the parathyroid gland, evidence indicates that the level of blood Ca ions regulates both the production and release of parathormone. Thus, when serum Ca is low, synthesis and release of parathormone are both stimulated; when serum Ca is elevated, these processes are inhibited.

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Early Development of Drug-Induced Hepatic Necrosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066942 ◽

1971 ◽

Vol 29 ◽

pp. 576-577

Author(s):

F. G. Zaki ◽

E. Detzi ◽

C. H. Keysser

Keyword(s):

Early Development ◽

Hepatic Necrosis ◽

Screening Tests ◽

Dense Matrix ◽

Sprague Dawley ◽

Electron Microscopic ◽

Drug Induced ◽

Hepatocellular Damage ◽

Sprague Dawley Rats ◽

Microscopic Studies

This study represents the first in a series of investigations carried out to elucidate the mechanism(s) of early hepatocellular damage induced by drugs and other related compounds. During screening tests of CNS-active compounds in rats, it has been found that daily oral administration of one of these compounds at a dose level of 40 mg. per kg. of body weight induced diffuse massive hepatic necrosis within 7 weeks in Charles River Sprague Dawley rats of both sexes. Partial hepatectomy enhanced the development of this peculiar type of necrosis (3 weeks instead of 7) while treatment with phenobarbital prior to the administration of the drug delayed the appearance of necrosis but did not reduce its severity.Electron microscopic studies revealed that early development of this liver injury (2 days after the administration of the drug) appeared in the form of small dark osmiophilic vesicles located around the bile canaliculi of all hepatocytes (Fig. 1). These structures differed from the regular microbodies or the pericanalicular multivesicular bodies. They first appeared regularly rounded with electron dense matrix bound with a single membrane. After one week on the drug, these vesicles appeared vacuolated and resembled autophagosomes which soon developed whorls of concentric lamellae or cisterns characteristic of lysosomes (Fig. 2). These lysosomes were found, later on, scattered all over the hepatocytes.

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Electron Microscopic identification of Pre-B Lymphocytes in the Bone Marrow of a Patient with Chronic Myelocytic Leukemic in Blast Crisis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100054352 ◽

1982 ◽

Vol 40 ◽

pp. 346-347

Author(s):

T. Mullin ◽

G. Yee ◽

M. Aheam ◽

J. Trujillo

Keyword(s):

Blast Crisis ◽

Immunoglobulin M ◽

Terminal Deoxynucleotidyl Transferase ◽

Transformation Theory ◽

Electron Microscopic ◽

Chemotherapeutic Sensitivity ◽

Microscopic Studies ◽

Hematopoietic Precursor ◽

Lymphoblastic Transformation ◽

B Lineage

There have been numerous reports in the current literature suggesting that hematopoietic precursor cells in some human chronic myelocytic leukemias (CML) undergo lymphoblastic transformation at the time of the acute blast crisis (BC) stage. The primary evidence offered in support of this transformation theory--lymphoblastic appearing morphology, increased terminal deoxynucleotidyl transferase (TdT) activity, and chemotherapeutic sensitivity to vincristine and prednisone--has been indirect, however, since these features may occur in nonlymphoid cells. More direct support for the Pre-B lineage of these cells has recently been provided by immunofluorescent light microscopic studies demonstrating the presence of intracytoplasmic immunoglobulin M (IgM) in these CML-BC cells.

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