Magnetic resonance imaging of Chiari malformations.

The authors describe the features of magnetic resonance (MR) images of Chiari type I and II malformations and present four illustrative cases. Downward displacement of the posterior fossa was more pronounced with type II than type I. A variety of intracranial anomalies were associated with the Chiari type II malformation, whereas type I was mainly associated with syringomyelia and craniovertebral changes. MR imaging is useful in the diagnosis of intracranial anomalies and those situated at the craniovertebral junction, including Chiari malformations.     

Biomechanical analysis of rehabilitation in the standing position.

Biomechanical analysis of the two-dimensional models composed from roentgenographic pictures and electromyographic analysis of the shear force exerted on the tibia during standing on both legs were conducted in 21 young adult males. The simultaneous contraction of the quadriceps and hamstrings was observed in all electromyograms. Amplitude observed on electromyograms of the hamstrings increased as the trunk flexion angle increased. The calculated average values of shear force were negative at every knee flexion angle (negative value means posteriorly directed force). As the trunk flexion angle increased, posterior drawer force increased at knee flexion angles of 30 degrees and 60 degrees. The simultaneous contraction of the quadriceps and the hamstrings was considered to be the main factor that influenced these results. Standing on both legs with knee and trunk flexion was considered to be applicable in the early stages after anterior cruciate ligament reconstruction.     

Protective effects of E3330, a novel quinone derivative, on galactosamine/tumor necrosis factor-alpha-induced hepatitis in mice.

Oral pretreatment with E3330, a novel quinone derivative, attenuated liver injury induced with tumor necrosis factor-alpha in galactosamine-sensitized mice. Tumor necrosis factor-alpha is known to induce inflammatory mediators such as leukotrienes and prostanoids. An in vitro study showed that E3330 inhibited the generation of leukotriene B4 and thromboxane B2, but enhanced prostaglandin E2 generation from rat peritoneal exudate cells stimulated with the Ca(2+)-ionophore, A23187. These findings suggest that the protective effect of E3330 on galactosamine/tumor necrosis factor-alpha hepatitis is due at least in part to its inhibition of the generation of leukotrienes. The inhibition of thromboxane B2 generation or the enhancement of prostaglandin E2 generation by E3330 may also contribute to its hepatoprotective effect.     

The locus coeruleus of the Japanese monkey (Macaca fuscata) does not express μ-opioid receptor-like immunoreactivity

It is well known that locus coeruleus (LC) of the rat shows intense μ-opioid receptor-like immunoreactivity (MOR-LI). In the course of our study on the distribution of MOR-LI in the brain of the Japanese monkey (Macaca fuscata), however, no MOR-LI was found in the LC although the distribution pattern of MOR-LI in other regions of the lower brainstem of the monkey was essentially the same as that observed in the rat. It was also found that immunoreactivity for Met-enkephalin, the most potent endogenous ligand for MOR, was intense in the rat LC, but very weak, if any, in the monkey LC. MOR may not be expressed in the monkey LC.     

Thalamocortical projections to layer I of the primary auditory cortex in the cat: a horseradish peroxidase study

HRP injected into layer I of the primary auditory cortex (AI) in the cat labeled neuronal cell bodies ipsilaterally in the medial, dorsal and ventrolateral divisions of the medial geniculate nucleus (MGN), suprageniculate nucleus, and nucleus of the brachium of the inferior colliculus. MGN neurons labeled after HRP injected into layer I were statistically smaller than those labeled after HRP injected into layer IV.     

Immunohistochemical localization of Na, K-ATPase in the choroid plexus

To determine if canine and rat choroid plexus Na⁺, K⁺-ATPase can be localized by immunoperoxidase staining after fixation and embedding, we prepared rabbit antiserum to purified canine kidney medulla Na⁺, K⁺-ATPase. When sodium dodecylsulfate polyacrylamide electrophoretic gels of purified canine kidney Na⁺, K⁺-ATPase and canine kidney microsomes were treated with antiserum followed by [¹²⁵I]protein A and autoradiography, the canine microsomes and purified Na⁺, K⁺-ATPase showed a prominent radioactive band coincident with the α-, β- and γ-subunits of the purified canine kidney enzyme.When the rabbit immunoglobulin that was purified from the Na⁺, K⁺-ATPase antiserum through DEAE-cellulose ion exchange chromatography was used for immunoperoxidase staining of the choroid plexus fixed with Bouin's fixative, intense immunoreactive staining was present on the epithelial cells of both choroid plexuses but was not found in the tissue around the vessel. The staining was especially confined to apical surfaces of the epithelial cells. The same procedure was performed in the canine kidney, and immunostaining was obtained in the tubules where Baskin and Stahl described the enzyme localization. No staining was seen with pre-immune serum of the normal rabbit. We concluded that both the canine and rat choroid plexus are rich in Na⁺, K⁺-ATPase, which plays an important role in cerebrospinal fluid (CSF) secretion.