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J. T. Youngjj - One of the best experts on this subject based on the ideXlab platform.

  • FUNDAMENTAL AND APPLIED TOXICOLOGY 5, 1050-1064 (1985) Long-Term Inhalation Toxicity of Hydrazine1
    2016
    Co-Authors: R. E. Schmidt, R. L. Eason, J. T. Youngjj
    Abstract:

    long intermittent exposures of rats, mice, hamsters, and dogs to hydrazine were conducted using concentrations of 0.05,0.25, 1.0, and 5.0 ppm. Rats were held 18 months postexposure; hamsters, 1 year postexposure; mice, 15 months postexposure; and dogs, 38 months postexposure. Male and female rats exhibited dose-dependent incidences of benign nasal adenomatous polyps and smaller numbers of malignant nasal epithelial tumors after 1 year of exposure to hydrazine and 18 months postexposure holding. Nasal tumors were often associated with chronic irritation and were most frequent in male rats, with an incidence of greater than 50 % in the highest exposure group. Hamsters exposed to 0.25-ppm and higher concentrations showed pathologic changes characteristic of degenerative disease, including amyloidosis. After exposure to 5.0 ppm hydrazine, hamsters developed a 10 % incidence of benign nasal polyps compared to 0.5 % in controls. Small numbers of colon neoplasms and Thyroid Parafollicular Cell adenomas were found in hamsters, but only in the highest concentrations tested. Lung adenomas appeared to be marginally increased in mice exposed to 1.0 ppm hydrazine, the highest concentration tested in this species. No consisten

R. E. Schmidt - One of the best experts on this subject based on the ideXlab platform.

  • FUNDAMENTAL AND APPLIED TOXICOLOGY 5, 1050-1064 (1985) Long-Term Inhalation Toxicity of Hydrazine1
    2016
    Co-Authors: R. E. Schmidt, R. L. Eason, J. T. Youngjj
    Abstract:

    long intermittent exposures of rats, mice, hamsters, and dogs to hydrazine were conducted using concentrations of 0.05,0.25, 1.0, and 5.0 ppm. Rats were held 18 months postexposure; hamsters, 1 year postexposure; mice, 15 months postexposure; and dogs, 38 months postexposure. Male and female rats exhibited dose-dependent incidences of benign nasal adenomatous polyps and smaller numbers of malignant nasal epithelial tumors after 1 year of exposure to hydrazine and 18 months postexposure holding. Nasal tumors were often associated with chronic irritation and were most frequent in male rats, with an incidence of greater than 50 % in the highest exposure group. Hamsters exposed to 0.25-ppm and higher concentrations showed pathologic changes characteristic of degenerative disease, including amyloidosis. After exposure to 5.0 ppm hydrazine, hamsters developed a 10 % incidence of benign nasal polyps compared to 0.5 % in controls. Small numbers of colon neoplasms and Thyroid Parafollicular Cell adenomas were found in hamsters, but only in the highest concentrations tested. Lung adenomas appeared to be marginally increased in mice exposed to 1.0 ppm hydrazine, the highest concentration tested in this species. No consisten

R. L. Eason - One of the best experts on this subject based on the ideXlab platform.

  • FUNDAMENTAL AND APPLIED TOXICOLOGY 5, 1050-1064 (1985) Long-Term Inhalation Toxicity of Hydrazine1
    2016
    Co-Authors: R. E. Schmidt, R. L. Eason, J. T. Youngjj
    Abstract:

    long intermittent exposures of rats, mice, hamsters, and dogs to hydrazine were conducted using concentrations of 0.05,0.25, 1.0, and 5.0 ppm. Rats were held 18 months postexposure; hamsters, 1 year postexposure; mice, 15 months postexposure; and dogs, 38 months postexposure. Male and female rats exhibited dose-dependent incidences of benign nasal adenomatous polyps and smaller numbers of malignant nasal epithelial tumors after 1 year of exposure to hydrazine and 18 months postexposure holding. Nasal tumors were often associated with chronic irritation and were most frequent in male rats, with an incidence of greater than 50 % in the highest exposure group. Hamsters exposed to 0.25-ppm and higher concentrations showed pathologic changes characteristic of degenerative disease, including amyloidosis. After exposure to 5.0 ppm hydrazine, hamsters developed a 10 % incidence of benign nasal polyps compared to 0.5 % in controls. Small numbers of colon neoplasms and Thyroid Parafollicular Cell adenomas were found in hamsters, but only in the highest concentrations tested. Lung adenomas appeared to be marginally increased in mice exposed to 1.0 ppm hydrazine, the highest concentration tested in this species. No consisten

S. J. Holt - One of the best experts on this subject based on the ideXlab platform.

  • Printed in Great Britain A STUDY OF GRANULE FORMATION IN THE
    2016
    Co-Authors: Bat Parafollicular Cell, E. A. Nunez, R. P. Gould, S. J. Holt
    Abstract:

    The fine structure of the bat Thyroid Parafollicular Cell has been examined at monthly intervals throughout the hibernating period. During November and December Parafollicular Cells appear either partly or totally degranulated and intact dense secretory granules are relatively sparse. The degranulated Cells exhibit an inconspicuous Golgi complex and relatively few lysosome-type bodies. Few degranulated Parafollicular Cells are present in Thyroid glands from bats collected in January. When found they are characterized by the presence of whorls of cytoplasmic agTanular membranes which enclose a central mass of Cellular debris. January bat Thyroids are characterized by the presence of three different types of Parafollicular Cell. One type contains no secretory granules. The cytoplasmic matrix of this type is rich in granular endoplasmic reticulum and free ribosomes and its small Golgi complex consists of several slightly dilated saccules. In close proximity to the Golgi complex are numerous small to medium-sized vesicles which often appear to merge with Golgi elements. Such vesicles are considered to represent the vehicle by which secretory product is transferred from the endoplasmic reticulum to the Golgi complex. The second type of Parafollicular Cell differs from the first in containing large numbers of intact dense secretory granules. It is also characterized by an extensive Golgi com

Bat Parafollicular Cell - One of the best experts on this subject based on the ideXlab platform.

  • Printed in Great Britain A STUDY OF GRANULE FORMATION IN THE
    2016
    Co-Authors: Bat Parafollicular Cell, E. A. Nunez, R. P. Gould, S. J. Holt
    Abstract:

    The fine structure of the bat Thyroid Parafollicular Cell has been examined at monthly intervals throughout the hibernating period. During November and December Parafollicular Cells appear either partly or totally degranulated and intact dense secretory granules are relatively sparse. The degranulated Cells exhibit an inconspicuous Golgi complex and relatively few lysosome-type bodies. Few degranulated Parafollicular Cells are present in Thyroid glands from bats collected in January. When found they are characterized by the presence of whorls of cytoplasmic agTanular membranes which enclose a central mass of Cellular debris. January bat Thyroids are characterized by the presence of three different types of Parafollicular Cell. One type contains no secretory granules. The cytoplasmic matrix of this type is rich in granular endoplasmic reticulum and free ribosomes and its small Golgi complex consists of several slightly dilated saccules. In close proximity to the Golgi complex are numerous small to medium-sized vesicles which often appear to merge with Golgi elements. Such vesicles are considered to represent the vehicle by which secretory product is transferred from the endoplasmic reticulum to the Golgi complex. The second type of Parafollicular Cell differs from the first in containing large numbers of intact dense secretory granules. It is also characterized by an extensive Golgi com