LIGHT AND ELECTRON MICROSCOPIC STUDIES OF THYROTROPHIN RELEASING HORMONE-INDUCED GROWTH HORMONE AND PROLACTIN RELEASE IN HYPOPHYSECTOMIZED RATS BEARING AN ECTOPIC PITUITARY GLAND

1977 ◽  
Vol 72 (3) ◽  
pp. 313-319 ◽  
Author(s):  
G. L. ROSSI ◽  
DOROTHEA PROBST ◽  
A. E. PANERAI ◽  
IRIT GIL-AD ◽  
DANIELA COCCHI ◽  
...  
Keyword(s):  
Prolactin Cells ◽  
Electron Microscopic ◽  
Time Intervals ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Highly Active ◽  
Microscopic Studies ◽  
Pituitary Glands ◽  
Hypophysectomized Rats

SUMMARY A light microscopic and ultrastructural study of anterior pituitary glands transplanted under the kidney capsule of hypophysectomized rats was performed, in basal conditions and after stimulation with thyrotrophin releasing hormone, at various intervals (24 h–2 months) after transplantation. Confirming previous biochemical findings, the results suggest that with time, somatotrophs acquire sensitivity to thyrotrophin releasing hormone and respond with increased exocytosis at doses that were found ineffective in pituitary glands in situ. Thryotrophin releasing hormone stimulation did not seem to influence the morphology of prolactin cells, which were already highly active under basal conditions at all time intervals.

The lurcher gene induces apoptotic death in cerebellar Purkinje cells

Development ◽  
1995 ◽  
Vol 121 (4) ◽  
pp. 1183-1193 ◽  
Author(s):  
D.J. Norman ◽  
L. Feng ◽  
S.S. Cheng ◽  
J. Gubbay ◽  
E. Chan ◽  
...  
Keyword(s):  
Purkinje Cells ◽  
Nuclear Dna ◽  
Neuronal Loss ◽  
Terminal Phase ◽  
Nuclear Condensation ◽  
Electron Microscopic ◽  
Apoptotic Death ◽  
Microscopic Studies ◽  
Cerebellar Purkinje Cells

In the neurologically mutant mouse strain lurcher (Lc), heterozygous animals display cell autonomous degeneration of cerebellar Purkinje cells beginning in the second postnatal week. During the course of our studies to identify the genetic lesion responsible for this disease (Norman et al., 1991), we have formulated an hypothesis suggesting that in Lc Purkinje cells homeostasis is sufficiently perturbed to lead to the activation of programmed cell death, thus resulting in neuronal loss and the consequent neurologic disease (Heintz, 1993). To address this possibility, we have examined the properties of Lc Purkinje cells as they die during the second postnatal week. Our light and electron microscopic studies demonstrate that dying Lc Purkinje cells exhibit the characteristic morphologic features of apoptosis, including nuclear condensation, axon beading and membrane blebbing. Using an in situ end-labeling method, we have also detected nicked nuclear DNA in these cells. Furthermore, we have examined the expression of the sulfated glycoprotein 2 (SGP2), whose mRNA is induced in both T-cells and prostate epithelial cells undergoing apoptotic death. We show by in situ hybridization that SGP2 is not expressed at detectable levels in normal Purkinje cells, but that its mRNA is present in Lc Purkinje cells prior to their death. Also expression of the Kv3.3b potassium channel, which marks the terminal phase of Purkinje cell differentiation, is evident in Lc Purkinje cells prior to their death. These data demonstrate that the Lc mutation induces apoptosis in cerebellar Purkinje cells following their maturation in postnatal cerebellum. Isolation of the Lc mutation and further analysis of its action in eliciting apoptosis can provide an important opportunity for understanding the etiology of neurodegenerative disease.

ELECTRON MICROSCOPIC STUDIES OF ANTERIOR PITUITARY GLANDS FROM LACTATING AND ESTROGEN-TREATED RATS1

Endocrinology ◽  
1961 ◽  
Vol 69 (1) ◽  
pp. 81-90 ◽  
Author(s):  
W. C. HYMER ◽  
W. H. McSHAN ◽  
R. G. CHRISTIANSEN
Keyword(s):  
Anterior Pituitary ◽  
Electron Microscopic ◽  
Microscopic Studies ◽  
Pituitary Glands

scholarly journals Scanning electron microscopic studies of Beauveria bassiana against Lipaphis erysimi Kalt

2017 ◽  
Vol 9 (1) ◽  
pp. 461-465
Author(s):  
Tanvi Sharma ◽  
Neelam Joshi ◽  
Anu Kalia
Keyword(s):  
Beauveria Bassiana ◽  
Lipaphis Erysimi ◽  
Electron Microscopic ◽  
Time Intervals ◽  
Mustard Aphid ◽  
Commercial Formulation ◽  
Fungal Isolates ◽  
Scanning Electron Microscopic ◽  
Microscopic Studies ◽  
Scanning Electron

This work was aimed to identify the LC50 of the indigenous fungal isolates for controlling L. erysimi infesta-tion in mustard aphid besides to probe the mechanism of action of the local isolates and comparison of the efficacy with the reference culture and commercial formulation ‘Mycojaal’. Three isolates of entomopathogenic fungi Beauveria bassiana were tested for infection on nymph of Lipaphis erysimi Kalt. using scanning electron microscopy (SEM) to record any variation. The SEM revealed adhesion of spores of B.bassiana followed by penetration of L.erysimi nymph surface. It was observed that all Beauveria isolates showed little variation with respect to penetration and adhesion at different time intervals. Further, lethal concentration (LC50) values of B. bassiana isolates against L. erysimi was recorded and was lowest (0.05x107 spores/ml) in B. bassiana MTCC 4495 and highest (0.11.X107 spores/ml) was recorded in native isolate F10 after 120 hours of treatment. The study has established the need for the isolation and evaluation of the indigenous Beauveria isolate. Moreover, it also exhibited the efficacy of the reference and commercially available biocontrol agents.

Polarized pigment granule transport occurs in the absence of microtubules in squirrelfish erythrophores: studies of the effects of estramustine

1987 ◽  
Vol 87 (4) ◽  
pp. 565-580
Author(s):  
M.E. Stearns ◽  
M. Wang
Keyword(s):  
Pigment Granule ◽  
Electron Microscopic ◽  
Microtubule Associated Proteins ◽  
Voltage Electron ◽  
Associated Proteins ◽  
Drug Inhibition ◽  
Microscopic Studies ◽  
10 Nm Filaments ◽  
Inhibition Studies

We have re-examined the involvement of microtubules in the process of pigment granule transport in squirrelfish erythrophores in situ (i.e. on scales). Light-microscopic studies revealed that following exposure to 5 microM-nocodazole for 1 h at 4 degrees C erythrophores retained an ability to aggregate and disperse their pigment uniformly, though at reduced rates. Serial thick-section stereo high-voltage electron-microscopic studies showed that the entire microtubule population was removed by drug treatment and that the microtubules were not reassembled as a result of pigment translocation processes in the presence of reduced levels of nocodazole (0.4 microM). Immunofluorescence microscopic studies confirmed that nocodazole (0.5-1 microM) produced rapid disassembly of the microtubules. Whole-mount electron-microscopic studies showed that the pigment granules were suspended in a cross-linking network of 3–10 nm filaments, which appeared to support ordered pigment transport in situ in the absence of microtubules. Drug inhibition studies showed that micromolar levels of estramustine, a novel anti-MAPs (microtubule-associated proteins) drug, reversibly inhibited pigment transport. The results suggest that an estramustine-sensitive cytomatrix component might produce polarized pigment transport in intact erythrophores.

Effects of synthetic mammalian thyrotrophin releasing hormone, somatostatin and dopamine on the secretion of prolactin and growth hormone from amphibian and reptilian pituitary glands incubated in vitro

1984 ◽  
Vol 102 (2) ◽  
pp. 175-180 ◽  
Author(s):  
T. R. Hall ◽  
A. Chadwick
Keyword(s):  
Rana Catesbeiana ◽  
Apparent Effect ◽  
Lower Vertebrate ◽  
Thyrotrophin Releasing Hormone ◽  
Factors Affecting ◽  
Releasing Hormone ◽  
Hypothalamic Extract ◽  
Pituitary Glands ◽  
Regulation Of Secretion

ABSTRACT Pituitary glands of grassfrog (Rana pipiens), bullfrog (Rana catesbeiana), clawed toad (Xenopus laevis) and two species of terrapin (Chrysemys picta and Pseudemys scripta) were incubated in medium containing hypothalamic extract (HE), thyrotrophin releasing hormone (TRH), somatostatin, dopamine, or combinations of these treatments. Prolactin and GH concentrations in the medium were determined by densitometry after polyacrylamide-gel electrophoretic separation. Hypothalamic extract stimulated secretion of both hormones in all species tested. Thyrotrophin releasing hormone stimulated secretion of prolactin and GH, showing a biphasic pattern of response. Dopamine had little effect alone, but inhibited HE-and TRH-stimulated release of prolactin, but not GH, in both amphibia and reptiles. Somatostatin by itself had no apparent effect on release of hormones, but it inhibited HE- and TRH-stimulated release of GH from both amphibian and reptilian pituitary glands. These results indicate that factors affecting mammals and birds also interact in the regulation of secretion of prolactin and GH in lower vertebrate species. J. Endocr. (1984) 102, 175–180

ULTRASTRUCTURAL MORPHOMETRY OF SPARSELY GRANULATED PROLACTIN CELL ADENOMAS OF THE HUMAN PITUITARY

1978 ◽  
Vol 89 (3) ◽  
pp. 521-529 ◽  
Author(s):  
D. J. McComb ◽  
K. Kovacs
Keyword(s):  
Endoplasmic Reticulum ◽  
Secretory Granules ◽  
Volume Density ◽  
Microscopic Level ◽  
Electron Microscopic Level ◽  
Prolactin Cells ◽  
Electron Microscopic ◽  
Human Pituitary ◽  
Hormone Synthesis ◽  
Highly Active

ABSTRACT Fifteen sparsely granulated prolactin-producing adenomas and 10 non-tumourous adenohypophyses, removed by surgical hypophysectomy, have been studied using morphometry at the electron microscopic level. Compared to non-tumourous prolactin cells, sparsely granulated adenomatous prolactin cells showed a significant decrease in diameter and volume density of secretory granules and an increased volume density of rough-surfaced endoplasmic reticulum and Golgi apparatus. The volume density of mitochondria remained unchanged. These results indicate that the cells of the adenoma are in a highly active functional state. It appears that the equilibrium between hormone synthesis, storage and release is altered in adenomatous prolactin cells.

Sodium channels in astrocytes of rat optic nerve in situ: immuno-electron microscopic studies.

Glia ◽  
1999 ◽  
Vol 28 (1) ◽  
pp. 84-84
Author(s):  
J.A. Black ◽  
B. Friedman ◽  
L.W. Elmer ◽  
S.G. Waxman
Keyword(s):  
Optic Nerve ◽  
Sodium Channels ◽  
Electron Microscopic ◽  
Microscopic Studies

In Situ Nitride Growth Studies by Low Energy Electron Microscopy (LEEM) and Low Energy Electron Diffraction (LEED)

1997 ◽  
Vol 3 (S2) ◽  
pp. 611-612
Author(s):  
E. Bauer ◽  
A. Pavlovska ◽  
I.S.T. Tsong
Keyword(s):  
Low Energy ◽  
Energy Electron ◽  
Ex Situ ◽  
Electron Microscopic ◽  
Insulating Layer ◽  
Light Emitting ◽  
Surface Sensitivity ◽  
Microscopic Studies ◽  
Low Energy Electron

Nitride films play an increasing role in modern electronics, for example silicon nitride as insulating layer in Si-based devices or GaN in blue light emitting diodes and lasers. For this reason they have been the subject of many ex situ electron microscopic studies. A much deeper understanding of the growth of these important materials can be obtained by in situ studies. Although these could be done by SEM, LEEM combined with LEED is much better suited because of its excellent surface sensitivity and diffraction contrast. We have in the past studied the high temperture nitridation of Si(l11) by ammonia (NH3)and the growth of GaN and A1N films on Si(l11) and 6H-SiC(0001) by depositing Ga and Al in the presence of NH3 and will report some of the results of this work for comparison with more recent work using atomic nitrogen instead of NH3.

SEM immunohistochemistry using alkaline phosphatase-labeled antibody

1990 ◽  
Vol 48 (3) ◽  
pp. 890-891
Author(s):  
Hisashi Hashimoto ◽  
Kazumasa Hoshino
Keyword(s):  
Alkaline Phosphatase ◽  
Computer Technology ◽  
Prolactin Cells ◽  
Lead Phosphate ◽  
Electron Microscopic ◽  
Sodium Phosphate Buffer ◽  
Scanning Electron Microscopic ◽  
Pituitary Glands ◽  
Electron Image ◽  
Backscattered Electron

Scanning electron microscopic immunohistochemical observations have been performed mainly using antibodies labeled by either virus particle or colloidal gold. In order to observe immunoreactive sites using these markers, however, high magnification is needed, even when the backscattered electron image (BEI) mode is utilized. Using alkaline phosphatase (ALPase)-labeled antibodies, lead phosphate can be deposited on immunoreactive sites and is detectable as strong signals on the BEI. Recent progress in computer technology enabled us to superimpose two or more images using different colors and gray levels. In this study, our attempt was made to detect the localization of prolactin cells in the pituitary gland and of laminin in the kidney using ALPase-labeled antibodies, by superimposing immunoreactive sites indicated by the BEI over their surface structures shown by the secondary electron image (SEI).Anterior pituitary glands obtained from female mice and kidneys from male mice were fixed by perfusion with 4% paraformaldehyde in 0.1M sodium phosphate buffer (SPB). After rinsing with 0.1M SPB, the fixed specimens were transferred into 50% dimethyl sulfoxide, frozen in liquid nitrogen and fractured, and rinsed with 0.1M SPB. The kidneys were pretreated with 0.1% pepsin in 0.01N HCl in order to have immunoreactivity against laminin restored.

Effects of prednisone on thyroid and gonadal endocrine function in dogs

1983 ◽  
Vol 96 (2) ◽  
pp. 293-NP ◽  
Author(s):  
R. J. Kemppainen ◽  
F. N. Thompson ◽  
M. D. Lorenz ◽  
J. F. Munnell ◽  
P. K. Chakraborty
Keyword(s):  
Hormone Secretion ◽  
Plasma Concentrations ◽  
Thyroid Tissue ◽  
Endocrine Function ◽  
Follicular Cell ◽  
Electron Microscopic ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Prednisone Treatment ◽  
Basal Plasma

To assess the effect of a glucocorticoid on thyroid and gonadal endocrine function, prednisone was administered on alternate days to dogs. The prednisone injections resulted in adrenocortical suppression, as shown by the response to ACTH. Basal plasma thyroxine and tri-iodothyronine concentrations were considerably reduced in prednisone-treated dogs. However, the thyroid response to injection of thyrotrophin-releasing hormone was not altered, indirectly demonstrating that pituitary release of TSH was not inhibited by prednisone. Similarly, the response of the thyroid to exogenous TSH was not reduced by prednisone treatment. Electron microscopic examination of thyroid tissue revealed accumulation of colloid droplets in the follicular cell cytoplasm of dogs treated with prednisone. It is postulated that prednisone may interfere with basal thyroid hormone secretion by inhibiting lysosomal hydrolysis of colloid in the thyroid follicular cell. Basal plasma concentrations of LH and testosterone, measured in the male dogs, were reduced by prednisone treatment. Responses of prednisone-treated dogs to luteinizing hormone releasing hormone were not significantly reduced. Prednisone administration did not alter testicular responsiveness to injection of human chorionic gonadotrophin. After orchidectomy, plasma LH values were significantly reduced in prednisone-treated dogs. Taken together, these results suggest that LH secretion in dogs is inhibited at the hypothalamic and/or pituitary level by prednisone administration, which consequently results in reduced testosterone concentrations.

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