scholarly journals THE STRUCTURAL CONDITIONS FOR OXYGEN SUPPLY TO MUSCLE CELLS: THE KROGH CYLINDER MODEL

2013 ◽  
Vol 216 (22) ◽  
pp. 4135-4137 ◽  
Author(s):  
E. R. Weibel
Keyword(s):  
Oxygen Supply ◽  
Muscle Cells ◽  
Cylinder Model ◽  
Krogh Cylinder

Measurement and Simulation of Water Transport During Freezing in Mammalian Liver Tissue

1997 ◽  
Vol 119 (3) ◽  
pp. 269-277 ◽  
Author(s):  
P. V. Pazhayannur ◽  
J. C. Bischof
Keyword(s):  
Water Transport ◽  
Rat Liver ◽  
Liver Tissue ◽  
Subzero Temperature ◽  
Biophysical Parameters ◽  
Cylinder Model ◽  
Chi Squared ◽  
Controlled Freezing ◽  
Cellular Water ◽  
Krogh Cylinder

Optimization of cryosurgical procedures on deep tissues such as liver requires an increased understanding of the fundamental mechanisms of ice formation and water transport in tissues during freezing. In order to further investigate and quantify the amount of water transport that occurs during freezing in tissue, this study reports quantitative and dynamic experimental data and theoretical modeling of rat liver freezing under controlled conditions. The rat liver was frozen by one of four methods of cooling: Method 1—ultrarapid “slam cooling” (≥ 1000° C/min) for control samples; Method 2—equilibrium freezing achieved by equilibrating tissue at different subzero temperatures (−4, −6, −8, −10°C); Method 3°-two-step freezing, which involves cooling at 5°C/min. to −4, −6, −8, −10 or −20°C followed immediately by slam cooling; or Method 4—constant and controlled freezing at rates from 5–400°C/min. on a directional cooling stage. After freezing, the tissue was freeze substituted, embedded in resin, sectioned, stained, and imaged under a light microscope fitted with a digitizing system. Image analysis techniques were then used to determine the relative cellular to extracellular volumes of the tissue. The osmotically inactive cell volume was determined to be 0.35 by constructing a Boyle van’t Hoff plot using cellular volumes from Method 2. The dynamic volume of the rat liver cells during cooling was obtained using cellular volumes from Method 3 (two-step freezing at 5°C/min). A nonlinear regression fit of a Krogh cylinder model to the volumetric shrinkage data in Method 3 yielded the biophysical parameters of water transport in rat liver tissue of: Lpg = 3.1 X 10−13 m3/Ns (1.86 μ/min-atm) and ELP = 290 kJ/mole (69.3 kcal/mole), with chi-squared variance of 0.00124. These parameters were then incorporated into the Krogh cylinder model and used to simulate water transport in rat liver tissue during constant cooling at rates between 5–100°C/min. Reasonable agreement between these simulations and the constant cooling rate freezing experiments in Method 4 were obtained. The model predicts that the water transport ceases at a relatively high subzero temperature (−10°C), such that the amount of intracellular ice forming in the tissue cells rises from almost none (=extensive dehydration and vascular expansion) at ≤5°C/min to over 88 percent of the original cellular water at ≥50°C/min. The theoretical simulations based on these experimental methods may be of use in visualizing and predicting freezing response, and thus can assist in the planning and implementing of cryosurgical protocols.

Analysis of the introduction and removal of glycerol in rabbit kidneys using a Krogh cylinder model

Cryobiology ◽  
1986 ◽  
Vol 23 (2) ◽  
pp. 150-160 ◽  
Author(s):  
D.E. Pegg ◽  
B. Rubinsky ◽  
M.P. Diaper ◽  
C.Y.C. Lee
Keyword(s):  
Cylinder Model ◽  
Krogh Cylinder

Analysis of cryophylactic agents introduction and removal in rabbit kidneys using a Krogh cylinder model

Cryobiology ◽  
1984 ◽  
Vol 21 (6) ◽  
pp. 705
Author(s):  
B. Rubinsky ◽  
D.E. Pegg ◽  
M.P. Diaper ◽  
C. Lee
Keyword(s):  
Cylinder Model ◽  
Krogh Cylinder

Ultrastructure of myoepithelial cell in parotid gland

1988 ◽  
Vol 46 ◽  
pp. 342-343
Author(s):  
C. N. Sun
Keyword(s):  
Parotid Gland ◽  
Osmium Tetroxide ◽  
Individual Cell ◽  
Branching Processes ◽  
Muscle Cells ◽  
Myoepithelial Cells ◽  
Uranyl Acetate ◽  
Thin Sections ◽  
Gland Carcinoma ◽  
Parotid Gland Carcinoma

Myoepithelial cells have been observed in the prostate, harderian, apocrine, exocrine sweat and mammary glands. Such cells and their numerous branching processes form basket-like structures around the glandular acini. Their shapes are quite different from structures seen either in spindleshaped smooth muscle cells or skeletal muscle cells. These myoepithelial cells lie on the epithelial side of the basement membrane in the glands. This presentation describes the ultrastructure of such myoepithelial cells which have been found also in the parotid gland carcinoma from a 45-year old patient.Specimens were cut into small pieces about 1 mm3 and immediately fixed in 4 percent glutaraldehyde in phosphate buffer for two hours, then post-fixed in 1 percent buffered osmium tetroxide for 1 hour. After dehydration, tissues were embedded in Epon 812. Thin sections were stained with uranyl acetate and lead citrate. Ultrastructurally, the pattern of each individual cell showed wide variations.

Immunogold localization of HMB-45 antigen in pulmonary lymphangiomyomatosis

1995 ◽  
Vol 53 ◽  
pp. 998-999
Author(s):  
J.M. Minda ◽  
E. Dessy ◽  
G. G. Pietra
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Muscle Cells ◽  
Ultrastructural Localization ◽  
Reproductive Age ◽  
Thin Sections ◽  
Smooth Muscle Proliferation ◽  
Hmb 45

Pulmonary lymphangiomyomatosis (PLAM) is a rare disease occurring exclusively in women of reproductive age. It involves the lungs, lymph nodes and lymphatic ducts. In the lungs, it is characterized by the proliferation of smooth muscle cells around lymphatics in the bronchovascular bundles, lobular septa and pleura The nature of smooth muscle proliferation in PLAM is still unclear. Recently, reactivity of the smooth muscle cells for HMB-45, a melanoma-related antigen has been reported by immunohistochemistry. The purpose of this study was the ultrastructural localization of HMB-45 immunoreactivity in these cells using gold-labeled antibodies.Lung tissue from three cases of PLAM, referred to our Institution for lung transplantation, was embedded in either Poly/Bed 812 post-fixed in 1% osmium tetroxide, or in LR White, without osmication. For the immunogold technique, thin sections were placed on Nickel grids and incubated with affinity purified, monoclonal anti-melanoma antibody HMB-45 (1:1) (Enzo Diag. Co) overnight at 4°C. After extensive washing with PBS, grids were treated with Goat-anti-mouse-IgG-Gold (5nm) (1:10) (Amersham Life Sci) for 1 hour, at room temperature.

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