The use of networks of dissociated rat dorsal root ganglion neurons to induce myelination by oligodencrocytes in culture

A neuronal culture system has been developed that has the demonstrated ability to induce myelin formation by added oligodendrocytes. Networks of dissociated dorsal root ganglion neurons were prepared by suppressing non-neuronal cells (i.e. fibroblasts and Schwann cells) with a continuous 2 week exposure to 10(-5)M fluorodeoxyuridine in the culture medium. After drug withdrawal, neuroglial cells were introduced in optic nerve implants from 1-2 week-old rats. These added glial cells migrated extensively over the unensheathed neurites and central myelin was formed by 2 weeks after the implant addition.

Abnormalities expressed in long-term cultures of dorsal root ganglia from the dystrophic mouse

We have compared the development in long-term tissue culture of dorsal root ganglia taken from normal and dystrophic mice. Cultures were prepared from late fetal (15--20 days) or neonatal mice of either the C57BL/6 dy2j/dy2j dystrophic (dy) or C57BL/6J +/+ (control) strain and maintained until fully myelinated (5 weeks or more). Analysis by light and electron microscopy indicated that the substantial ensheathment failure present in certain dy nerve roots in vivo is not expressed in cultures; myelination and Schwann cell numbers are comparable to control cultures. On the other hand, many of the subtle abnormalities more recently described in distal parts of peripheral nerves of dystrophic mice are expressed in the dy cultures. These include: (a) discontinuity in the basal lamina surrounding both myelin-forming and non-myelinating Schwann cells: (b) elongated nodes of Ranvier occurring along otherwise well myelinated nerve fibers; (c) relatively short myelin internodes that are increased in thickness as well as irregularities of internode length along a nerve fiber; (d) Schwann cell nuclei substantially displaced from the central point of myelin internodes; and (e) occasional regions of incomplete ensheathment of unmyelinated nerve fibers. In discussing these observations, we present arguments that the dy nerve lesion may be explained by the presence of an abnormality in the extracellular matrix of the peripheral nerve tissues of the dy mouse.

[Fundamental and clinical studies on cefamandole in the field of obstetrics and gynecology (author's transl)]

1) Tissue concentrations of cefamandole (CMD) one hour after the end of 2 g/30 approximately 60 minutes drip infusion were 7.3 approximately 13.1 microgram/g in uterus, ovary and oviduct. These concentrations were higher than MICs of 70 approximately 100% of causative organisms, including Staphylococcus aureus, Escherichia coli, Klebsiella, Proteus mirabilis, Enterobacter and Citrobacter, isolated from the infections in the field of obstetrics and gynecology. 2) CMD was administered to 14 patients with moderate infections in the field of obstetrics and gynecology at a daily dose of 4 g for 5 approximately 7 days. The overall clinical efficacy obtained was as follows; excellent in 7 cases (50%), good in 3 cases (21%) and poor in 4 cases (29%). 3) Antimicrobial activity of CMD against causative organisms resembled that of CEZ. 4) No adverse effects and abnormal laboratory findings were observed. From the above, we considered that CMD was an effective and safe antibiotic against infections in the field of obstetrics and gynecology.

Congenital dilatation of intrahepatic bile ducts associated with hepatic fibrosis and medullary sponge kidney--reconstruction and microdissection study

An autopsy case of a four-year-old female with congenital dilatation of intrahepatic bile ducts with bilateral medullary sponge kidney is presented. The liver and kidney were investigated by reconstruction with serial sections and the kidney was also studied by microdissection. In this case the dilatations of collecting tubules and intra- and extrahepatic bile ducts were observed. We regard these lesions as developmental anomalies since these sites of both organs are excretory ducts derived from the endoderm. The liver cirrhosis observed at autopsy had developed in the course of the disease because the liver architecture was well preserved in the biopsy material. The patient had fatal cholangitis without cholelithiasis.

[Laboratory and clinical studies on cefoxitin in the field of obstetrics and gynecology (author's transl)]

1) Serum concentrations of cefoxitin (CFX) was lower than that of cefazolin (CEZ), but the tissue concentrations of CFX were higher in ovary, oviduct and uterus compared with CEZ. 2) CFX was administered to 15 patients with moderate intrapelvic or urinary tract infections at a dose of 4 g per day for 5 to 7 days. The overall results obtained were as follows; excellent in 6 cases, good in 6 cases. The CFX treatment was effective in all patients, 8 cases, with intrapelvic infections. 3) The majority of organisms detected were E. coli (12 strains), and the antimicrobial activity of CFX against them was superior to those of CEZ and CET. 4) No side effects and abnormal laboratory findings were observed. 5) It is considered that CFX will be a useful drug in the field of obstetrics and gynecology.

Abnormalities of the sciatic nerves of dystrophic mice with reference to the large U-axons

A statistical study using regression analysis was used to evaluate the density of axonal organelles in dystrophic peripheral nerves. The slope of the density of neurotubules (NT) in myelinated (M-) axons was different from that in small unmyelinated (U-) axons. The slope of the density of NT in large U-axons (larger than 1.5 micron in diameter) was similar to that of the M-axons in both the dystrophic and control mice. There was a higher density of NT in the dystrophic M-axons than in the controls in the anterior, posterior and mixed nerves of the sciatic nerve. There was also a higher density of NT in the dystrophic small U-axons than in the controls. There was a higher density of neurofilaments (NF) of M-axons in the dystrophic mice than in the controls. On the contrary, the NF of small U-axons were lower in density in the dystrophic mice. These results were different from our previous reports, which were observed in the distal part, depending on when the groups of U-axons were divided (Okada, Mizuhira and Nakamura 1976a).

Abnormally combined myelinated and unmyelinated nerves in dystrophic mice

Abnormally combined M- and U-nerves were observed in the peripheral nerves of C57BL dystrophic mice. They were counted in the sciatic nerves of the dystrophic mice 3 times more frequently than in control mice. The myelin disappeared beyond the nodes of Ranvier just as in the dysmyelination of dystrophic mice. Some of the U-axons inside the myelin were enveloped by Schwann cell cytoplasm while others were not. The myelinated U-axons contained cored vesicles, dilated endoplasmic reticulum and degenerate mitochondria. These abnormalities might cause disordered function and be related to the pathophysiology of murine muscular dystrophy.

Dysmyelination in the sciatic nerves of dystrophic mice

Ultrastructural alterations were observed in the sciatic nerve of dystrophic mice. Myelin sheaths were abnormal in shape, abruptly ceased beyond a node of Ranvier, leaving the axon naked. These changes were seen in both afferent and efferent nerve fibres. Apparent embryonal Schwann cells and Schwann cells which were associated with increased lysosomes in the cytoplasm were observed in the proximal portion. There is a relative decrease in Schwann cells in the cross-section of the radicular parts, and a relative increase in the distal parts. The mean number of neurotubules per unit area was smaller while the mean number of the neurofilaments was larger in U-axons, in the dystrophic mice than in the controls. In M-fibres, neurotubules and neurofilaments showed no significant difference between systrophic and control mice.

Abnormalities of the sciatic nerves of dystrophic mice, with reference to nerve counts and mean area of axons

Ultrastructural changes of the sciatic nerves of c58bl/6j-dydy mice were examined. Nerve counts were calculated and the area of axons was measured in these nerve tissue. Many large bundles of unmyelinated nerves were observed at the proximal portion of the sciatic nerve without cytoplasm or basement membrane of the Schwann cell. These bundles were composed of axons of various sizes and shapes, including some vary large axons. The large unmyelinated axons decreased in number and size as nerves descended to the distal portion. The myelinated nerves showed irregular shapes. Some myelinated nerves were enveloped in very thin myelin sheaths for the mouse age. The destructed myelin was often observed from the radix to the distal portion of sciatic nerves. They lost their myelin sheaths at the Ranvier node, and descended for long distances with naked axons. The neighboring myelin segments of naken axons showed unusually bizarre shapes. They seemed to be the abnormal development of the demyelinated axons. Such findings were very similar to those of the embryonal developing peripheral nerves. It was concluded that the muscular dystrophy of the C57BL/6J-dydy mice might be related to dysmyelination and to the decrease in the number of myelinated nerves.