Experimental Studies of the Dynamics of Herring Bodies. Ultrastructure of Axon Dilatations Developing at the Site of Compression or Transection of Neurosecretory Axons in the Grass Frog Rana pipiens

Author(s):  
H.-D. Dellmann ◽  
J. R. Carithers
1979 ◽  
Vol 14 (1-3) ◽  
pp. 167-174 ◽  
Author(s):  
KIM L. CARPENTER ◽  
JAMES B. TURPEN

Author(s):  
J. R. Ruby ◽  
R. F. Dyer ◽  
R. G. Skalko ◽  
R. F. Gasser ◽  
E. P. Volpe

An electron microscope examination of fetal ovaries has revealed that developing germ cells are connected by intercellular bridges. In this investigation several species have been studied including human, mouse, chicken, and tadpole (Rana pipiens). These studies demonstrate that intercellular connections are similar in morphology regardless of the species.Basically, all bridges are characterized by a band of electron-dense material on the cytoplasmic side of the tri-laminar membrane surrounding the connection (Fig.l). This membrane is continuous with the plasma membrane of the conjoined cells. The dense material, however, never extends beyond the limits of the bridge. Variations in the configuration of intercellular connections were noted in all ovaries studied. However, the bridges in each individual species usually exhibits one structural characteristic seldom found in the others. For example, bridges in the human ovary very often have large blebs projecting from the lateral borders whereas the sides of the connections in the mouse gonad merely demonstrate a slight convexity.


Author(s):  
J. H. Hayden

In a previous study, Allen video-enhanced constrast/differential interference constrast (AVEC-DIC) microscopy was used in conjunction with immunofluorescence microscopy to demonstrate that organelles and vesicle move in either direction along linear elements composed of microtubules. However, this study was limited in that the number of microtubules making up a linear element could not be determined. To overcome this limitation, we have used AVEC-DIC microscopy in conjunction with whole mount electron microscopy.Keratocytes from Rana pipiens were grown on glass coverslips as described elsewhere. Gold London Finder grids were Formvar- and carbon coated, and sterilized by exposure to ultraviolet light. It is important to select a Formvar film that gives a grey reflection when it is floated on water. A silver film is too thick and will detract from the image in the light microscope.


Author(s):  
Kent McDonald ◽  
David Mastronarde ◽  
Rubai Ding ◽  
Eileen O'Toole ◽  
J. Richard McIntosh

Mammalian spindles are generally large and may contain over a thousand microtubules (MTs). For this reason they are difficult to reconstruct in three dimensions and many researchers have chosen to study the smaller and simpler spindles of lower eukaryotes. Nevertheless, the mammalian spindle is used for many experimental studies and it would be useful to know its detailed structure.We have been using serial cross sections and computer reconstruction methods to analyze MT distributions in mitotic spindles of PtK cells, a mammalian tissue culture line. Images from EM negatives are digtized on a light box by a Dage MTI video camera containing a black and white Saticon tube. The signal is digitized by a Parallax 1280 graphics device in a MicroVax III computer. Microtubules are digitized at a magnification such that each is 10-12 pixels in diameter.


Author(s):  
Ina Grau ◽  
Jörg Doll

Abstract. Employing one correlational and two experimental studies, this paper examines the influence of attachment styles (secure, anxious, avoidant) on a person’s experience of equity in intimate relationships. While one experimental study employed a priming technique to stimulate the different attachment styles, the other involved vignettes describing fictitious characters with typical attachment styles. As the specific hypotheses about the single equity components have been developed on the basis of the attachment theory, the equity ratio itself and the four equity components (own outcome, own input, partner’s outcome, partner’s input) are analyzed as dependent variables. While partners with a secure attachment style tend to describe their relationship as equitable (i.e., they give and take extensively), partners who feel anxious about their relationship generally see themselves as being in an inequitable, disadvantaged position (i.e., they receive little from their partner). The hypothesis that avoidant partners would feel advantaged as they were less committed was only supported by the correlational study. Against expectations, the results of both experiments indicate that avoidant partners generally see themselves (or see avoidant vignettes) as being treated equitably, but that there is less emotional exchange than is the case with secure partners. Avoidant partners give and take less than secure ones.


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