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G D Meetz

Publications and source records attributed to G D Meetz.

7 recordsLinked to original sources
PubMed1979

Morphologic features of the caudal neurosecretory system in the blueback herring, Pomolobus aestivalis.

The caudal neurosecretory system of the blueback herring, Pomolobus aestivalis, captured in freshwater, was examined. Neurosecretory cells were identified readily in terminal spinal cord segments. The axonal processes of these neurosecretory cells formed a discrete, ventrally placed bundle which terminated in a conspicuous ventral enlargement from the filum terminale. This enlargement comprises the neurohaemal contact zone or urophysis. The neurosecretory terminals were engorged with secretory granules in these fishes from a freshwater environment. The non-neuronal component of the urophysis also was examined in this study. These glial cells were dispersed throughout the urophysis. Most often they were found ensheathing the terminal neurosecretory processes. These cells showed a resemblance to neurohypophysial pituicytes. Although mentioned in the literature, these glial cells have not been examined with the electron microscope. The ultrastructural features of the glial cells and their relation to the neurosecretory constituents are described in this report.

Animals↗
PubMed1976

The relation between capillaries and neurons in the caudal neurosecretory system of Pomatomus saltatrix.

The caudal neurosecretory system of Pomatomus saltatrix was examined. Particular interest was devoted to the perikarya of the neurosecretory cells. The majority of these cells were characterized by a close association with the capillary network. The cells appeared to ensheath the capillaries thus bringing the nucleus and perinuclear cytoplasm into close association with the capillaries.

Animals↗
PubMed1976

Inhibitory effect of shark serum on the Lewis lung carcinoma.

The growth and metastasis of transplanted Lewis lung carcinoma in C57BL/6J mice were inhibited by an ip injection of whole serum from Carcharhinus plumbeus, the sandbar shark. Tumors failed to develop in 69% of the animals inoculated with shark serum on days 0, 3, and 6 after tumor transplantation. Histologic examination of the tumor site at days 3 and 6 showed that tumor cells were pyknotic, and evidence of lysis of tumor cells and minor leukocytic infiltration existed. Tumor cells were not in tissue sections from day 15, and these animals still had no symptoms at day 216. The mean tumor volume of the remaining 31% of the treated animals was less than that of controls; they had a prolonged mean survival time, but ultimately they died from metastases, as did the controls. Urea- and hemoglobin-treated animals and those pretreated or intralesionally treated with shark serum were similar to the controls in both tumor kinetics and survival times.

Animals↗
PubMed1970

Electron microscopy of the ammoniacal silver reaction for histones in the erythropoietic cells of the chick.

The product of the postformalin ammoniacal silver reaction, which has been claimed to distinguish lysine-rich from arginine-rich histones with the light microscope on the basis of a color difference, was examined in developing erythroid cells of chick bone marrow with the electron microscope. Stem cells and early erythroblasts exhibit no, or little, ammoniacal silver reaction product, while small basophilic erythroblasts, polychromatophilic erythrocytes, and reticulocytes exhibit an increasing amount of reaction product as maturation proceeds. The reaction product is in the form of discrete electron-opaque particles associated with heterochromatin. The ammoniacal silver reaction in the erythroid cell series is interpreted as reflecting either the accumulation of newly synthesized arginine-rich histones or changes in the availability of reactive sites in preformed histones.

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