Control of applicator position by hysterography in HDR afterloading therapy of endometrium cancer.
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Brachytherapy↗
Biomedical subjects
G Roth
Publications and source records attributed to G Roth.
Effect control of HDR afterloading radiation in uterine cancer by NMR imaging with and without GD-DTPA.
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Aged↗
Mathematical model and simulation of retina and tectum opticum of lower vertebrates.
The processing of information within the retino-tectal visual system of amphibians is decomposed into five major operational stages, three of them taking place in the retina and two in the optic tectum. The stages in the retina involve (i) a spatially local high-pass filtering in connection to the perception of moving objects, (ii) separation of the receptor activity into ON- and OFF-channels regarding the distinction of objects on both light and dark backgrounds, (iii) spatial integration via near excitation and far-reaching inhibition. Variation of the spatial range of excitation and inhibition allows to account for typical activities observed in a variety of classes of retina ganglion cells. Mathematical description of the operations in the tectum opticum include (i) spatial summation of retinal output (mainly of class-2 and class-3 retina ganglion cells), and (ii) direct or indirect lateral inhibition between tectal cells. In the computer simulation, first the output of the mathematical retina model is computed which, then, is used as the input to the tectum model. The full spatio-temporal dynamics is taken into account. The simulations show that different combinations of strength of lateral inhibition on the one side and the response properties of the retina ganglion cells on the other side determine the response properties of tectal cell types involved in object recognition.
Amphibians↗
Neuropathies with prolonged conduction block, single and grouped fasciculations, localized limb myokymia.
Fourteen patients presented prolonged conduction block (CB) related to hereditary neuropathy with liability to pressure palsies (n = 7), neuropathy with proximal multifocal persistent CB (n = 2), radiation plexopathy (n = 3) and chronic acquired polyneuropathy (n = 2). All subjects presented both single and grouped fasciculation potentials that resulted in visible limb myokymia in 9 patients. This ectopic activity was recorded only in muscles affected by the CB, was more important in severe or complete CB, and often arose from terminal branches of blocked axons. These fasciculations and grouped fasciculations therefore appear to be causally related to the CB. In the presence of localized myokymia, a prolonged CB should be suspected.
Chronic Disease↗
Nuclear magnetic resonance imaging of a patient with an ectopic pregnancy.
We attempted to demonstrate the morphological changes of an extrauterine pregnancy by nuclear magnetic resonance imaging. Spin echo mode was used to take images in all three space directions. An enlargement of the uterus with an empty cavity and a hyperplasia of the supporting vasculature were demonstrated as alterations correlating with an extrauterine pregnancy.
Adult↗
Differential effects of hydrocortisone, fluocortolone, and aldosterone on nocturnal sleep in humans.
Previous experiments have suggested that sleep processes are sensitive to influences of corticosteroids. The present experiment was designed to compare effects of three different corticosteroids on human sleep: fluocortolone (a synthetic pure glucocorticoid), cortisol which possesses glucocorticoid and mineralocorticoid activity, and aldosterone (the major mineralocorticoid). Ten male adult subjects were tested in four experimental nights according to a double-blind latin-square design under conditions of either 1.0 mg of aldosterone, 20 mg of fluocortolone, 80 mg of hydrocortisone, or placebo. Substances were administered orally (fluocortolone, 23.00 h) or infused iv throughout the night (hydrocortisone, aldosterone) starting at 23.00 h. Hydrocortisone and fluocortolone induced a substantial reduction of rapid eye movement sleep. Hydrocortisone increased slow wave sleep activity. No such effect was observed after fluocortolone. Effects on sleep processes of aldosterone, in general, seemed to be neglegible. The results demonstrate differential effects of synthetic glucocorticoid, cortisol, and aldosterone on sleep in humans, which may be attributed to the heterogeneity of corticosteroid receptors in the brain.
Administration, Oral↗
Detection of conduction block by monopolar percutaneous stimulation of the brachial plexus.
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Brachial Plexus↗
The total artificial heart.
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Cardiomyopathies↗
[Nuclear magnetic resonance imaging of uterine cancer with and without the administration of the paramagnetic contrast medium Gd-DTPA].
Patients with a corpus carcinoma were examined by magnetic resonance imaging before and after application of the paramagnetic contrast agent Gd-DTPA. The images were obtained by spin echo technique with the repetition times 0.5 s or 1.8 s and the echo times 35/70 ms. The dosis of the contrast agent was 0.1 mmol per kg body weight. The contrast between myometrium and tumour increased after injection of the contrast agent and structures within the tumour can be better differentiated. The pelvic organs (bowel and urinary bladder) can be seen in greater detail. Images taken with short repetition times after application of Gd-DTPA show greater contrast than pictures picked up with the same imaging parameters without contrast agent. Furthermore, there is an improvement compared with images taken with long repetition times.
Aged↗
Motor neuropathy with proximal multifocal persistent conduction block, fasciculations and myokymia. Evolution to tetraplegia.
We describe a patient with chronic asymmetric motor neuropathy, which began in the upper extremity. The paretic muscles showed abundant fasciculations and myokymia but only little amyotrophy. Electrophysiologic examination revealed proximal multifocal persistent conduction block (CB) not located at the usual entrapment sites, and arrhythmic isolated or grouped fasciculation potentials originating distally on blocked axons. Over the years, new CBs developed, which led to tetraplegia, and amyotrophy slowly increased with progressive denervation. This patient differs from the cases of chronic acquired demyelinating polyneuropathy described in the literature by the absence of sensory deficit and the proximal location of CB.
Demyelinating Diseases↗
The structure of the brainstem and cervical spinal cord in lungless salamanders (family plethodontidae) and its relation to feeding.
We present an HRP study of the sensory tracts and motor nuclei associated with feeding (especially use of the tongue) in plethodontid salamanders (mainly Batrachoseps attenuatus, Bolitoglossa subpalmata, Desmognathus ochrophaeus, Eurycea bislineata, and Plethodon jordani). The nerves studied are VII (ramus hyomandibularis only), IX, X, XI, the first spinal nerve (hypoglossus), and the second spinal nerve. Two types of sensory projections are universally found in the brainstem: superficial somatosensory projections of VII, IX, and X, and deeper visceral sensory projections of IX and X to the fasciculus soltarius. The first spinal nerve and the spinal accessory nerve (XI) have no sensory projections, but the second spinal nerve has typical projections along the dorsal funiculus of the spinal cord. The motor nuclei of VII ramus hyomandibularis, IX, and X form a combined nucleus situated at the level of the IX/X root complex. The nucleus of the first spinal nerve is well separated from the combined nucleus and is situated rostral and caudal to the obex. The rostral part of the motor nucleus of the second spinal modestly overlaps that of the first. The motor nucleus of the spinal accessory nerve is more or less restricted to the region of the second spinal nerve. Its fibers leave the brain through the last root of the IX/X complex and the related ganglion. Bolitoglossine and nonbolitoglossine differ in the architecture of the spinal nuclei. Two distinct types of motor neurons occur in spinal nuclei of nonbolitoglossine species--some of those with tongue projection--but only one type is found among the tongue-projecting bolitoglossine group.
Animals↗
Principles of self-generation and self-maintenance.
Living systems are characterized as self-generating and self-maintaining systems. This type of characterization allows integration of a wide variety of detailed knowledge in biology. The paper clarifies general notions such as processes, systems, and interactions. Basic properties of self-generating systems, i.e. systems which produce their own parts and hence themselves, are discussed and exemplified. This makes possible a clear distinction between living beings and ordinary machines. Stronger conditions are summarized under the concept of self-maintenance as an almost unique character of living systems. Finally, we discuss the far-reaching consequences that the principles of self-generation and self-maintenance have for the organization, structure, function, and evolution of single- and multi-cellular organisms.
Animals↗
Trends in the functional morphology and sensorimotor control of feeding behavior in salamanders: an example of the role of internal dynamics in evolution.
Organisms are self-producing and self-maintaining, or "autopoietic" systems. Therefore, the course of evolution and adaptation of an organism is strongly determined by its own internal properties, whatever role "external" selection may play. The internal properties may either act as constraints that preclude certain changes or they open new pathways: the organism canalizes its own evolution. As an example the evolution of feeding mechanisms in salamanders, especially in the lungless salamanders of the family Plethodontidae, is discussed. In this family a large variety of different feeding mechanisms is found. The authors reconstruct this evolutionary process as a series of "bifurcation points" of either constraints or opportunities forming a sequence of preconditions for the formation of a high-speed projectile tongue characteristic of tropical salamanders. Furthermore, it is shown how parallel evolution of seemingly unrelated domains within an organism such as respiratory physiology, life history biology and pattern of ontogeny has rather direct relevance to the feeding biology, thus demonstrating that organisms always evolve as wholes.
Animals↗
[Muscle-nerve ephapse in chronic denervation? Axonal localization].
Muscle-to-nerve ephaptic responses, taking place between a reinnervated motor unit and a motor axon, have been reported in the case of chronic denervation (Roth and Magistris, 1985). One of these responses is described here. Its main features are that it manifests itself as a motor unit potential, which, when present, is evoked either as a direct tardive response (RE), or as an indirect F response, the two potentials never being observed together on any recording. The characteristics of these potentials show that two distinct competitive pathways lead to the same muscular fiber group which suggests the existence of an ephaptic connection. Furthermore, a slight difference in the shape of the RE and F potentials suggests an axon terminal branch localisation of this ephapse.
Carpal Tunnel Syndrome↗
Long-lasting conduction block in hereditary neuropathy with liability to pressure palsies.
We detected 29 conduction blocks in 12 patients with hereditary neuropathy and liability to pressure palsies. The blocks occurred at entrapment sites, most often the ulnar nerve at the elbow. Some had lasted for several years. This kind of block seems to be characteristic of the neuropathy, and may be related to the localized thickening of myelin ("tomacula"). In one patient with two permanent and severe blocks, neurolysis was beneficial.
Humans↗
[Hysterography with afterloading-applicator in place. A simple method for improving the treatment planning of uterine cancer].
Anatomical configurations often are an obstacle to a convenient dose-distribution in intracavitary afterloading irradiation. Multiple applicators (splay applicators, twin applicators) cannot be introduced in all cases because of the necessary cervix dilatation. In several cases can be demonstrated, that a defined intracavitary irradiation is possible only by hysterographic control of the intrauterine position of the applicator. By this control generally a mono-applicator is sufficient, which can be placed according the anatomy of the uterine cavity in each session. For this purpose a simple hysterographic method with applicator in position is demonstrated, which requires only few additional effort during intracavitary irradiation.
Aged↗
Distribution of accessory and hypoglossal nerves in the hindbrain and spinal cord of lungless salamanders, family Plethodontidae.
Study of the innervation of the musculature related to feeding behavior in plethodontid salamanders by means of the horseradish peroxidase (HRP) technique has demonstrated the existence of a true spinal accessory nerve which innervates neck musculature, enters the brain via the ganglion of IX/X cranial nerves and has its motor neurons within the nucleus of the second spinal nerve. Further, it has been shown that the first spinal nerve, being strictly motor, alone constitutes the ramus hypoglossus and is, therefore, homologous to the hypoglossus of amniotes.
Animals↗
Motor axon loop: an electroneurographic response.
A new kind of response to the stimulation of the median and ulnar nerves was observed in 10 patients. It is a motor unit showing a late latency in response to a weak stimulus and then suddenly a normal latency when the intensity is increased to a critical level. These two responses can be evoked at any level of a distinct nerve segment, the difference between their latencies being constant. The late response cannot be elicited below this segment and the normal response cannot be elicited above this segment. Its F-latency is delayed and does not vary when the late response changes in a normal one. The conduction velocity along the axon seems normal. We propose the hypothesis of a motor axon loop along the nerve, with the recurrent portion traveling in the " grandes ellipses" or the classical anastomosis. These kinked axons are probably congenital; their frequency is still unknown.
Adult↗