Neutron spectrum at the underground laboratory for the ultra low background experiment.

We measured the background neutron spectrum using a Bonner sphere spectrometer at the YangYang underground laboratory, where the vertical earth overburden is approximately 700 m. The neutron fluence rate and the energy spectrum were determined through the unfolding procedure. The measured neutron fluence rate was (0.242 ± 0.008) n cm(-2)h(-1) for k=1, and most of the neutrons were below 20 MeV.

Lipid A-associated proteins from Porphyromonas gingivalis stimulate release of nitric oxide by inducing expression of inducible nitric oxide synthase.

BACKGROUND AND OBJECTIVE: The purpose of this study was to examine the effects of lipid A-associated proteins from Porphyromonas gingivalis, a major cause of inflammatory periodontal disease, on the production of nitric oxide and expression of inducible nitric oxide synthase in the murine macrophage cell line, RAW264.7. We also attempted to throw light on the signaling mechanisms involved in P. gingivalis lipid A-associated protein-induced nitric oxide production. MATERIAL AND METHODS: The lipid A-associated proteins from P. gingivalis 381 were prepared by standard hot phenol-water extraction of endotoxin isolated by the butanol method. Nitric oxide production was assayed by measuring the accumulation of nitrite in culture supernatants. Western blot analysis of inducible nitric oxide synthase and analysis of reverse transcription-polymerase chain reaction products were carried out. RESULTS: We found that P. gingivalis lipid A-associated proteins can induce inducible nitric oxide synthase expression and stimulate the release of nitric oxide without additional stimuli, and we demonstrated that multiple signaling pathways, such as nuclear factor-kappaB, microtubule polymerization, protein tyrosine kinase, protein kinase C, and mitogen-activated protein kinase cascades, are involved in P. gingivalis lipid A-associated protein-stimulated nitric oxide production. The production of nitric oxide required l-arginine. CONCLUSION: The present study clearly shows that P. gingivalis lipid A-associated proteins fully induced inducible nitric oxide synthase expression and nitric oxide production in RAW264.7 cells in the absence of other stimuli. The ability of P. gingivalis lipid A-associated proteins to promote the production of nitric oxide may be important in the pathogenesis of inflammatory periodontal disease.

Location of the primary motor cortex in schizencephaly.

BACKGROUND AND PURPOSE: Functional reorganization of the brain can result from congenital brain disorders as well as from brain infarction. The purpose of our study was to use functional MR imaging to determine whether reorganization of brain function occurs in patients with schizencephaly. METHODS: Four patients with schizencephaly (three right-handed, one ambidextrous) presented with seizures. Associated lesions included agenesis of the corpus callosum (n = 1) and absence of the septum pellucidum (n = 1). Functional MR imaging was performed in each patient using a single-section fast low-angle shot (FLASH) blood oxygen level-dependent (BOLD) technique at 1.5 T in a standard head coil. The motor cortex was initially identified on an axial T1-weighted anatomic image. Thirty consecutive images were obtained during a motor task consisting of repetitive finger-to-thumb opposition. The percentage of change in increased signal intensity was calculated for the primary motor area. An ipsilateral activation index was used to compare the affected with the unaffected hemisphere. RESULTS: The percentage of change in increased signal intensity in the area of activation ranged from 4.8% +/- 0.9 to 9.2% +/- 1.2 (mean, 5.6% +/- 1.5). The ipsilateral activation index in the affected hemisphere was 0.00 to 0.38, whereas that in the unaffected hemisphere was 15.4 to infinity. The difference in the ipsilateral activation index between each hemisphere was considered significant. CONCLUSION: Our results showed increased activation in the unaffected hemisphere in patients with schizencephaly, which may reflect functional reorganization of the motor area in patients with this congenital disorder.

Coxiella (Q fever)-associated myelopathy.

We describe six men with a slowly progressive myelopathy characterized by asymmetric, incomplete spinal cord syndrome manifested with a thoracic sensory level, mild spastic paraparesis, and urinary incontinence. The spinal cord lesions were evident by MRI in four of them. Coxiella burnetii infection was confirmed in the blood of all patients by immunofluorescence microscopic assay (IFA) and transmission electron microscopy (TEM). In two patients, we detected C burnetii by TEM and IFA using CSF from the patients inoculated onto fresh peripheral blood lymphocyte. Four patients, treated with appropriate antibiotics, responded either with partial resolution of symptoms or arrest of further neurologic progression. In three, the MRI lesions decreased in size.

Prolonged ictal amnesia with transient focal abnormalities on magnetic resonance imaging.

A previously healthy woman had a prolonged amnestic state caused by complex partial status epilepticus with bilateral mesiotemporal lobe involvement confirmed by EEG with nasopharyngeal electrodes. A magnetic resonance imaging (MRI) scan obtained shortly after recovery from the amnesia showed reversible focal abnormalities consisting of increased signal intensity on T2-weighted scan in the mesiotemporal lobe.

A case of herpes zoster myelitis: positive magnetic resonance imaging finding.

A 33-year-old man developed a progressive myelopathy after a characteristic skin lesion of herpes zoster involving the right C3 and C4 dermatomes. The lesions were recognizable in the T2-weighted image of the magnetic resonance imaging (MRI) as increased signal intensities throughout the long segments of the spinal cord with maximal in the cervical portion, which was compatible with the pathological findings reported in autopsy studies.

Comparison between electrophysiologic and morphologic changes in lead induced peripheral neuropathy in rats.

Compound nerve action potential (CNAP) of the mixed peripheral nerve is composed of A alpha beta, A delta, and C potentials. All components of CNAPs in the sciatic nerve were recorded by stimulating the tibial nerve of both control and lead-poisoned rats. Marked decrease of nerve conduction velocity and prolonged duration were found in A alpha beta and A delta fibers especially in large myelinated A alpha beta fibers. The amplitude decreased in A alpha beta potential, but the area did not change. In C potential produced by activation of unmyelinated fibers, nerve conduction velocity slightly decreased, but the amplitude and area did not significantly change. Pathologic correlates revealed prominent segmental demyelination with significant decrease of large myelinated fiber densities. Minimal axonal degeneration of unmyelinated fibers was present. We can conclude that electrophysiologic changes in the lead-poisoned rats correlate with pathologic changes in them.