Spontaneous cerebrospinal fluid hypovolaemia: a therapeutic dilemma?

Spontaneous intracranial hypotension is characterized by orthostatic headaches in conjunction with reduced cerebrospinal fluid volume (CSF) and characteristic imaging findings. We report the clinical course of six consecutive patients with spontaneous intracranial hypotension who were followed between 4 months and 2.5 years. The characteristic orthostatic headaches were present in five patients. Diffuse pachymeningeal enhancement on brain magnetic resonance imaging (MRI) was evident in all cases. CSF detected elevated protein content in three of six patients. In only two of our six patients a first epidural blood patch resulted in complete symptom resolution lasting 4 months and 1 year. Four patients received a second epidural blood patch and one patient also received a third. In four patients, follow-up brain MRI revealed re-occurrence of the typical MRI features and all of them suffered from orthostatic symptoms at this time. Only four patients are free of complaints after an average follow-up period of 10 months. Symptom relief within 7 days from an epidural blood patch is accepted to be diagnostic for spontaneous intracranial hypotension. However, our data illustrate that the clinical course of the syndrome is very unstable and the epidural blood patch is less effective than widely accepted.

Continuous transcranial magnetic stimulation during positron emission tomography: a suitable tool for imaging regional excitability of the human cortex.

In six healthy volunteers, H(2)(15)O positron emission tomography (PET) was employed to evaluate rate-dependent functional activation of the left primary sensorimotor hand area (SM1(HAND)) during subthreshold repetitive transcranial magnetic stimulation (rTMS). Using an eight-shaped coil, continuous trains of rTMS were delivered during nine 50-s H(2)(15)O PET scans. Nine different stimulation frequencies were used, ranging from 1 to 5 Hz. Stimulus intensity was set at 10% below active motor threshold. During three additional PET scans, an ineffective rTMS was applied via another eight-shaped coil, which was held 10 cm above the vertex. Statistical parametric mapping was employed to assess relative differences in normalized regional cerebral blood flow (rCBF) across conditions. Compared with ineffective rTMS, subthreshold rTMS increased normalized rCBF in the stimulated SM1(HAND). Moreover, the increase in rCBF in the left SM1(HAND) showed a linear positive relationship with the rate of rTMS, indicating a rate-dependent functional activation of the stimulated SM1(HAND). These data demonstrate that, by varying the variables of rTMS across scans, continuous rTMS during H(2)(15)O PET provides a noninvasive tool to study the regional excitability profile of a distinct cortical area.

Studies on intake of heavy metals by Bradybaena similaris, land snails, by XAFS measurement.

We have applied XAFS in order to determine both the chemical form and the place where heavy metals are stored in cultivated land snails. From Cu and Zn XANES spectra, the shells showed similar patterns as those of soft tissues and not like carbonates. This indicates that heavy metals are not completely taken into carbonate structures but are present within organic components in the shells. In addition, Cu XANES spectra of the samples showed low absorption edge-energy in the order of hepatopancreas, mantle, body, and shell. By comparing samples with standard reagents, each of which has only S- or O-ligand, it was found that the metals in hepatopancreas exist mostly as S-bound chemical components. To quantify the relative abundance of S-bound chemical component, partial least-squares (PLS) regression was applied. The PLS result indicated that for Cu, S-bound compound was higher in the order of hepatopancreas > mantle > body >shell.

[New insights into brain function by combination of transcranial magnetic stimulation and functional brain mapping]. / Neue Einblicke in die Hirnfunktion durch Kombination von transkranieller magnetischer Kortexstimulation und funktioneller zerebraler Bildgebung.

The present paper aims to summarize potential applications of transcranial magnetic stimulation (TMS) combined with functional brain imaging. Transcranial magnetic stimulation is a well-established noninvasive tool for stimulating circumscribed areas of the human cortex. Functional imaging techniques such as positron emission tomography, functional magnetic resonance imaging, and electroencephalographic mapping enable assessment of TMS-related functional brain activation. A combination of TMS and functional imaging can be useful in three principal ways. (1) Brain imaging before TMS is helpful in defining the accurate coil position over a distinct cortical area which is targeted by TMS. Since TMS can be used to interfere with regional cortical function during a given task, the effects of focal TMS on task performance can help to clarify the task-specific functional contribution of a given cortical area which has previously shown task-related activation in a functional imaging study. (2) Imaging the brain during TMS is a promising approach for assessing cortical excitability and intracerebral functional connectivity. (3) By evaluating lasting effects of TMS, brain imaging after TMS can be employed to study the plasticity of the human cortex. Moreover, this approach will help to advance our understanding of therapeutical effects related to TMS.

Quenching and liquid chromatographic determination of polythionates in natural water.

Polythionates in highly acidic, crater-lake water have been determined by ion-chromatography and high-performance microbore liquid chromatography. The first technique allows the determination of tri-, tetra- and pentathionate in excess of 10 ppm, and the second allows analysis for tetra-, penta- and hexathionate in excess of 0.2 ppm. The methods for preserving polythionates in natural solutions are also discussed. The recommended procedures for storage are to add hydroxylamine hydrochloride to sample solutions or to exclude atmospheric oxygen by using Winkler oxygen-determination bottles, followed by storage in a refrigerator at 5 degrees .

Correlation of volcanic activity with sulfur oxyanion speciation in a crater lake.

The Yugama crater lake at Kusatsu-Shirane volcano, Japan, contains nearly 2200 tons (2800 parts per million) of polythionate ions (Sn O(6)(2-), where n = 4 to 9). Analytical data on lake water sampled before and during eruptions in 1982 showed that the concentrations of polythionates decreased and sulfate increased in response to the preeruption activities of the subaqueous fumaroles. These changes were observed 2 months before the first phreatic explosion on 26 October 1982. The monitoring of polythionates and sulfate in crater lake water is a promising means of anticipating potential volcanic eruption hazards.