Association Between the Accumulation of Pentosidine at the Sciatic Nerve and Cutaneous Hindpaw Hypersensitivity in a Rat Ovariectomy Model

1983 ◽

Vol 41 ◽

pp. 650-651

Author(s):

Amankwah K.S. ◽

A.D. Weberg ◽

R.C. Kaufmann

Keyword(s):

Sciatic Nerve ◽

Maternal Smoking ◽

Ultrastructural Level ◽

Uranyl Acetate ◽

Nerve Tissue ◽

Ultrastructural Changes ◽

Cacodylate Buffer ◽

And Control ◽

Spontaneous Delivery

Previous research has revealed that passive (involuntary inhalation) tobacco smoking during gestation can have adverse effects upon the developing fetus. These prior investigations did not concentrate on changes in fetal morphology. This study was undertaken to delineate fetal neural abnormalities at the ultrastructural level in mice pups exposed in utero to passive maternal smoking.Pregnant study animals, housed in a special chamber, were subjected to cigarette smoke daily from conception until delivery. Blood tests for determination of carbon monoxide levels were run at 15-18 days gestation. Sciatic nerve tissue from experimental and control animals were obtained following spontaneous delivery and fixed in 2.5% gluteraldehyde in 0.1M cacodylate buffer pH 7.3. The samples were post-fixed in osmium ferrocyanide (1:1 mixture of 1.5% aqueous OSO4 and 2.5% K4 Fe(CN)6). Following dehydration, the tissues were infiltrated with and embedded in Spurr. Sections were stained with uranyl acetate and lead citrate.

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Incorporation of Cholesterol into Peripheral Nerve Myelin

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100094930 ◽

1972 ◽

Vol 30 ◽

pp. 334-335

Author(s):

Frank A. Rawlins

Keyword(s):

Electron Microscope ◽

Sciatic Nerve ◽

Electron Microscope Autoradiography ◽

Myelin Sheaths ◽

Microscope Autoradiography ◽

Grain Distribution ◽

Sciatic Nerves ◽

Autoradiographic Analysis ◽

Old Mice ◽

Short Times

Several speculations exist as to the site of incorporation of preformed molecules into myelin. The possibility that an autoradiographic analysis of cholesterol-1,2-H3 incorporation at very short times after injection might shed some light in the solution of that problem led to the present experiment.Cholesterol-1,2-H3 was injected intraperitoneally into 24 tenday old mice. The animals were then sacrificed at 10,20,30,40,60,90,120 and 180 min after the injection and the sciatic nerves were processed for electron microscope autoradiography. To analyze the grain distribution in the autoradiograms of cross and longitudinal sections from each sciatic nerve myelin sheaths were subdivided into three compartments named: outer 1/3, middle 1/3 and inner 1/3 compartments.It was found that twenty min. after the injection of cholesterol -1.2-H3 (Figs. 1 and 2), 55% of the total number of grains (t.n.g) found in myelin were within the outer 1/3 compartment, 9% were within the middle 1/3 and 36% within the inner 1/3 compartment

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Facilitated migration of cells from a transected peripheral nerve over collagen fibers: in vivo observations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100156420 ◽

1989 ◽

Vol 47 ◽

pp. 888-889

Author(s):

Arthur J. Wasserman ◽

Azam Rizvi ◽

George Zazanis ◽

Frederick H. Silver

Keyword(s):

Sciatic Nerve ◽

Peripheral Nerve ◽

Collagen Gel ◽

Collagen Fibers ◽

Control Group ◽

Guide Tube ◽

Sprague Dawley ◽

Silicone Tube ◽

Thin Sections

In cases of peripheral nerve damage the gap between proximal and distal stumps can be closed by suturing the ends together, using a nerve graft, or by nerve tubulization. Suturing allows regeneration but does not prevent formation of painful neuromas which adhere to adjacent tissues. Autografts are not reported to be as good as tubulization and require a second surgical site with additional risks and complications. Tubulization involves implanting a nerve guide tube that will provide a stable environment for axon proliferation while simultaneously preventing formation of fibrous scar tissue. Supplementing tubes with a collagen gel or collagen plus extracellular matrix factors is reported to increase axon proliferation when compared to controls. But there is no information regarding the use of collagen fibers to guide nerve cell migration through a tube. This communication reports ultrastructural observations on rat sciatic nerve regeneration through a silicone nerve stent containing crosslinked collagen fibers.Collagen fibers were prepared as described previously. The fibers were threaded through a silicone tube to form a central plug. One cm segments of sciatic nerve were excised from Sprague Dawley rats. A control group of rats received a silicone tube implant without collagen while an experimental group received the silicone tube containing a collagen fiber plug. At 4 and 6 weeks postoperatively, the implants were removed and fixed in 2.5% glutaraldehyde buffered by 0.1 M cacodylate containing 1.5 mM CaCl2 and balanced by 0.1 M sucrose. The explants were post-fixed in 1% OSO4, block stained in 1% uranyl acetate, dehydrated and embedded in Epon. Axons were counted on montages prepared at a total magnification of 1700x. Montages were viewed through a dissecting microscope. Thin sections were sampled from the proximal, middle and distal regions of regenerating sciatic plugs.

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