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K H Booz

Publications and source records attributed to K H Booz.

At least 19 recordsLinked to original sources
PubMed1999

Identification of somatosensory pathways by focal-cooling-induced changes of somatosensory evoked potentials and EEG-activity--an experimental study.

OBJECT: Function-preserving neurosurgery requires methods to identify functionally important CNS-areas intraoperatively. We investigated whether a combination of focal cerebro-cortical cooling and monitoring of somatosensory evoked potentials (SEP) is suited for this task, i.e. whether it is able to outline structures belonging to the somatosensory pathway. METHODS: In 17 Wistar rats the somatosensory cortex was focally cooled by 20 degrees C below the initial tissue temperature for periods of five minutes. A cryoprobe with a tip diameter of 3 mm was used and tissue temperatures were measured below and at different distances to the cryoprobe. Tibial nerve evoked SEPs and EEG-spectra were recorded continuously. RESULTS: During cortical cooling the SEP-responses showed a marked delay and amplitude increase of the cortically generated components P13 and N18 and a small latency increase of the subcortically generated wave III. EEG-spectra were depressed mainly in the low frequency range. All cooling effects were reversible and in light- as well as electron-microscopic examinations no tissue damage was found. CONCLUSIONS: Focal cooling of the cortex induces easily recognizable and reversible changes of the bio-electrical activity without causing any histological damage. Therefore the method seems suitable for identifying eloquent areas. It can be expected that clinical application of the cooling technique in combination with intraoperative electrophysiological monitoring will be helpful to further lower the risk of neurosurgical operations. We propose that cooling mainly interferes with the synaptic transmission within the somatosensory cortex, because the observed amplitude increase can be explained by cold-induced depression of inhibitory cortical activity (disinhibition).

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PubMed1998

The ependyma in chronic hydrocephalus.

H-Tx rats produce congenitally hydrocephalic offspring with varying severity of the condition. We used moderately hydrocephalic rats without evident clinical signs of hydrocephalus and normal controls from the same stock when they were at least 1.5 years old. Macroscopic anatomy was studied by MRI and in fixed brain slices and the ultrastructure of the ependyma, with REM. Apart from markedly stretched areas, where the ependyma was totally destroyed and subependymal structures directly exposed to the CSF, the density of ependymal microvilli and of tufts of cilia was reduced in proportion to the ventricular distension of a given area. A supraependymal "network"--never seen before in acute hydrocephalus--was found, whose purpose is probably to prevent further ventricular enlargement. We conclude that even in arrested hydrocephalus the ependymal sequelae of hydrocephalus are similar to those of the acute stage, illustrating the extremely limited potential for recovery, but the organism seems nevertheless to react with an internal stabilization of the ventricular system.

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PubMed1987

Structural alterations in the spinal cord during progressive communicating syringomyelia. An experimental study in the cat.

A hydrocephalic-hydromyelic condition was induced in adult cats by causing the closure of the lateral apertures with intracisternal injections of kaolin. After displaying the symptoms characteristic of increased intracranial pressure, which lasted about 10-14 days but varied somewhat in intensity from animal to animal, the cats recovered. From approximately the 2nd post-operative week onward, a distended central canal was revealed by ventriculography; subsequently cavities developed in the tissue of the cord that communicated with the canal. Most cavities were located dorsal to the canal. The surfaces of the distended canal and the cavities showed that in ventral areas the ependyma streched but remained intact, whereas in dorsal areas it ruptured, exposing the nerve fibers to the cerebrospinal fluid (CSF). In cats which had been hydrocephalic for up to 2 years the walls of the cavities were covered by gliotic scar tissue; the nerve fibers were no longer exposed directly to the CSF.

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PubMed1985

The ependyma of the cat central canal, with particular reference to its mitochondria-containing bulbs.

The ultrastructure of the ependyma in the central canal of adult cats was examined in both the scanning and the transmission electron microscopes (SEM and TEM). The same morphological details were seen in the ependyma of the central canal as have so frequently been described in the ependyma of the brain ventricular system, for example bundles of cilia, single cilia, microvilli and occasional small cytoplasmic protrusions. The supraependymal cells and supraependymal nerve fibers found in the central canal also resembled those seen in the ventricular system. The most striking feature of the canal ependyma were the large, spherical bodies containing numerous mitochondria. They are therefore called mitochondria-containing bulbs. In sections the bulbs were seen to be connected by long, slender stalks to neurons in subependymal position. In some respects the mitochondria-containing bulbs resemble the processes of cerebrospinal fluid-contacting neurons.

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PubMed1979

[Secretory phenomena at the ependyma of the sulcus hypothalamicus Monroi of the fetal rat. A histochemical and electron microscopic study].

In a localized area above the sulcus hypothalamicus Monroi ventriculi tertii of the rat ependymal structures are observed, which only occur between the 18th and 20th day of gestation. They were investigated with the aid of lightmicroscopic, ultrastructural and histochemical technics. The surface of the ventricular wall is rendered irregular by protrusions and deposits. Neurosecretory stains and histochemical examination give no positive results. Apical parts of the ependymal cells are fingershaped, dome-like and of spheric appearance. The equipment of the protrusions with organels is variable. Some of them contain a fine granular ground plasma, polyribosomes and occasional profiles of the endoplasmatic reticulum. Others are impacted with optic empty or substantial vacuols. Vacuols merging in the cellular membrane evacuate their content into the ventricular space. Multivesicular bodys engorged with vesicles are together with those, which lie empty in the ventricular cavity. Empty, buddle like and frequently folded membrane protrusions suggest that cellular content has been delivered into the ventricle.

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PubMed1975

Secretory phenomena at the ependyma of the IIIrd ventricle of the embryonic rat.

On the basis of previous observations of the third ventricle, the brains of rat embryos in the 17 to 21 gestation days were examined by light- and electron microscope as well as histochemically. Following results were obtained: 1. Between the 18th and 20th gestation days supraependymal secretion spherules and intraventricular secretion masses were observed in the rostral part of the third ventricular lumen. The intraventricular structures are not demonstrable with neurosecretory stains; they are PAS-negative and do not stain with periodic-acid-bisulfite-aldehydethionine. All histochemical reactions performed were negative. 2. The morphological finding in the same frontal plane is not uniform. Dorso-ventral difference exist between one ependymal region which lies caudal to the subfornical organ and an area in the same plane which is situated further ventrally near the entrance to the foramina Monroi (Fig. 1 a). In the superior portion, the supraependymal structures are spherical or bottle-shaped formations and are easily definable. In the lower ventricular portion densely situated ependymal protrusions are seen which become sperical only in the ventricular lumen. 3. In both instances (the spherical and flask-shaped protrusions of the superior portion and the strongly shaped protrusions of the lower portion of the third ventricle) cytoplasmic protuberances containing more or less dense, fine-grain ground plasma and a differentiated number of polyribosomes can be seen. Using the Richardson stain, chromophobe protrusions are seen to possess a diffuse ground plasma and only a few ribosomes, while chromophile protrusions have a dense ground plasma and numerous polyribosomes rosettes. Only rarely are single vesicles observed in the protrusions. 4. The ependyma cells contain densely packed, rough-walled endoplasmic reticulum whose cisterns are irregularly dilated and filled with electron-dense material; they also contain many ribosomes and dictyosomes. The organelles are accumulated mainly in the apical cell portions. A terminal web spans the cell surface and attaches to the zonulae adhaerentes, preventing the flow of cell organelles into the organelle-free secretory protrusions. 5. The functional implication of the ependymal secretion, which appears in the third ventricle for a few days only, during embryonic development, is still unknown and is the goal of subsequent examinations.

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