Reaction of the vasa nervorum of the facial nerve during stimulation with neurotransmitters.
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Acetylcholine↗
Biomedical subjects
A Schadel
Publications and source records attributed to A Schadel.
[Neurogenic inflammation and area of involvement of the facial nerve of the rat].
Antidromic electrical stimulation of sensory nerves produces vascular hyperpermeability, plasma protein extravasation and oedema. The initial phase of this inflammatory reaction is induced by the release of the neuropeptides CGRP, SP and NKA; the later phase is induced by mast cells. In previous investigations we were able to show that the facial nerve of the rat contains CGRP, SP and NKA as well as mast cells. The same mechanism--increased vascular permeability--plasma extravasation--oedema--is thought to be part of the pathogenesis of Bell's palsy. Hence, we tried to produce neurogenic inflammations in the facial nerves of six adult Wistar rats. To assess plasma extravasation we used Evans blue, a dye which binds to serum albumin, according to the method described by Brokaw and White (1992). Having cut the facial nerve distal of the stylomastoid foramen we induced a neurogenic inflammation by the application of an electrical stimulus to the distal part of the nerve. In comparison to the contralateral, non-stimulated side, we recognized that the inflammatory reactions were limited to the area of the skin innervated by the posterior auricular nerve. So far, we can transfer this "neurogenic inflammation model" the well-known relationship between nerves and inflammatory reactions to this limited area innervated by the facial nerve.
Animals↗
Innervation of epi- and endoneurial compartments of rat facial, vagus and sciatic nerves as studied by double-labeling immunofluorescence.
The mediators of axon terminals innervating the blood vessels and connective tissue compartments of rat peripheral nerves (facial, vagus and sciatic nerve) were investigated by means of double-labeling immunofluorescence. Sympathetic noradrenergic/neuropeptide-Y-immunoreactive axons innervated epi- and endoneurial arterial blood vessels; noradrenergic fibers without neuropeptide Y immunoreactivity terminated in the endoneurium between the axons of the main nerve trunk. Presumably sensory nerve terminals immunoreactive to substance P/calcitonin gene-related peptide supplied epi- but not endoneurial arteries and arterioles, and ran freely in the endoneurial space. Axons immunoreactive to vasoactive intestinal peptide innervated epineurial blood vessels of the facial and vagus nerve but were absent from the vasa nervorum of the sciatic nerve. The findings are in line with the concept, based upon previous pharmacological experiments, of a tonic constrictory and dilatory innervation of vasa nervorum. However, as judged from the distribution patterns of the neurochemically distinct axonal populations, vascular segments of different connective tissue compartments (epi- versus endoneurial) and body regions (sciatic versus cranial nerves) are differentially addressed by each of these axonal populations. This might have implications for the development of region-specific neuropathies.
Animals↗
[Blood supply to the facial nerve].
At the present time there is no final explanation for the etiology of Bell's palsy. The theory of pathophysiology involving a combined primary and/or secondary ischemia is now well-accepted. As such, it is supposed that there is a dysfunction of the blood vessels which supply the nerve. This is followed by a hyperpermeability and transudation which lead to edema of the nerve and compression of the blood supply. The vicious circle starts and the final result is facial paralysis. The blood supply of the facial nerve has been described previously in the literature, although there have been no experimental investigations on in vivo perfusion of the nerve. In the present study we evaluated the percentage of those vessels perfused among the total blood vessels found in facial nerves of Wistar rats. Animals were examined after i.v.-injections of Evans blue dye, with perfused vessels demonstrable under a fluorescence microscope. Forty-eight hours later, the same tissue section was stained by indirect immunofluorescence and the primary antibody used was directed against myosin of non-muscle sources. This antibody cross-reacted with myosin of vascular endothelial cells and thus allowed identification of any existing blood vessels. More than 90% of the immunostained vessels were labeled with the dye, showing that almost all vessels were perfused.
Animals↗
[Reconstruction of oral cavity and oropharyngeal defects with a pure muscle-fascia flap].
As a rule carcinomas of the oral cavity and oropharynx are not diagnosed in early stages. Surgical resections of these tumors including margins of safety invariably result in large defects. At present, one-stage flap techniques are preferred for reconstruction, as exemplified by pectoralis major myocutaneous flaps and free revascularized jejunum grafts. The skin island of the myocutaneous flap is underlayed by fat tissue as a sliding surface. Temporary sutures are necessary but have the disadvantage of producing a convex configuration. This shape compromises anatomical reconstruction of the oral cavity and oropharynx. Robertson et al. in 1985 demonstrated an alternative method for a muscle-fascia flap from the pectoralis major muscle. In comparison to the temporalis muscle-fascia flap, the pectoralis muscle-fascia flap is associated with a lesser incidence of complications. Although it is still too early to conclude their definitive use, their application in some cases is now being questioned because of such factors as reduced time of anesthesia.
Carcinoma, Squamous Cell↗
[Neuropeptides in the facial nerve of the rat].
The occurrence of peptidergic nerve fibres containing substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY) in the cerebral arteries and arterioles is well known. NPY is a vasoconstrictor, while SP, CGRP and VIP induce cerebrovascular dilatation. Vascular dysregulation of the vasa nervorum of the facial nerve is believed to be a central factor in the pathogenesis of Bell's palsy. Hilger's theory of the primary and/or secondary oedema which is followed by the vicious circle is generally accepted. It was our aim to describe the occurrence and distribution of neuropeptides in the blood vessels of the facial nerve. We examined the facial nerves of 6 male Wistar rats using the indirect immunofluorescence technique. There is not only a characteristic distribution of the neuropeptides in different parts of the facial nerves, but there are also beaded axons of sensory nerve fibers, which are localised freely in the endoneurium. These SP and CGRP containing beaded axons which densely innervate the nerve in the bony canal, are capable of inducing an oedema by neurogenic inflammation. Our findings suggest that there must be a vascular regulation in the facial nerve which is controlled by various neuropeptides.
Animals↗
[Evaluating the effectiveness of chemotherapy in patients with head-neck tumors using positron emission tomography (PET scan)].
Positron emission tomography (PET) demonstrates the qualitative and quantitative characteristics of multiple metabolic pathways. In a prospective study we evaluated the metabolism of glucose in the tumors of ten patients suffering from head and neck cancer before and after chemotherapy with cisplatin and 5-fluorouracil. Using 18-fluorodeoxyglucose (FDG), it was possible to show changes in tumor metabolism after chemotherapy. In general, chemotherapy reduced the volume of the primary tumor and the lymph nodes. There was a linear relation between the changes in metabolism and growth rate, but in a few patients the lymph nodes and the primary tumor showed a different metabolic reaction. With FDG metabolism and PET we were able to determine the response rate of the tumor in vivo before chemotherapy.
Antineoplastic Combined Chemotherapy Protocols↗
[Risks of a cartilage-bone bank with reference to HIV infection].
Allogenic transplants have an established place in reconstructive procedures. For years it has been suspected that lyophilized dura mater can transmit Creutzfeld-Jakob disease. HIV infection with fully manifest AIDS and a mortality of up to 100% is now also increasing in significance. It is necessary to assess the risk of transferring HIV with allogenic transplants because HIV passes into the cell via specific surface receptors and is integrated within the chromosome. Experimental data on disinfection and sterilization of allogenic transplants stored within chromosomes and their inactivation are not available. Allogenic transplants are only used in operations for life-threatening disease. As a rule, these are elective operations which must meet the highest safety standards, also with regard to the danger of infection. Collaboration with a transplantation team is essential.
Bone Transplantation↗
[The effects of cold on facial nerve function].
Synonyms like "paralysie á frigore" and "rheumatic palsy" imply a dysfunction of the vasa nervorum during coldness application. Cooling the nerve, however, only reduces perfusion by 18%. Cooling of the facial nerve with pure ice to 0 degrees C leads to a functional loss due to a blockade of the temperature-controlled Na-K-channels. The vasomotor regulation of the nerve vessels under these conditions seems to be relatively unimportant.
Animals↗
[Experimental study of Gore-Tex in the treatment of the skull base].
Fractures of the skull base are frequently accompanied by dural injuries. Lyophilized dura mater is very suitable for dural reconstruction at the level of the smooth convex posterior wall of the frontal sinus but surgery in the region of the sphinoid tectum and lateral to the falx cerebri is difficult. The Gore-Tex patch is very soft and comfortable. Vascular prostheses are manufactured from this material and have been implanted successfully for years. This material was subjected to a check of histocompatibility in animal experiments by intracranial implantation as a replacement for lyophilized dura mater. Lyodura is replaced by granulations of collagenous tissue. Gore-Tex is incorporated with fibroblastic and osteoblastic penetration. This alloplastic material should only be used under specific conditions.
Animals↗
[An animal experiment study using the Gore-Tex soft tissue patch as a replacement for lyophilized dura mater].
Fractures of the skull base are often accompanied by dural lesions. Lyophilized dura mater is very valuable for dural reconstruction at the level of the smooth convex posterior wall of the frontal sinus, but surgery in the region of the uneven ethmoidal roof and lateral to the falx cerebri is difficult. The Gore-Tex patch is very soft and comfortable: vascular prostheses manufactured from this material have been implanted successfully for years. This material was subjected to a check of histocompatibility as a replacement for lyophilized dura in animal experiments by intracranial implantation. Lyodura is replaced by collagenous tissue, whereas Gore-Tex is incorporated by fibroblastic and osteoblastic penetration. This alloplastic material is an alternative tissue to lyophilized dura but should be reserved for special situations.
Animals↗
Measurement of regional cerebral blood flow and accentuation of the primary auditory cortex with single photon emission computed tomography.
Conventional brain scanning uses polar tracers which do not penetrate the normal blood-brain barrier. Radiolabeled amines like 123-iodoamphetamine (IMP) cross the barrier to inhibit serotonin and norepinephrine in synaptosomes. Studies of cerebral perfusion and function seem to be successful with such labeling. We advance the hypothesis for an increased IMP uptake in the stimulated primary auditory cortex. The method of single photon emission computed tomography (SPECT) is described. We have also been able to demonstrate marking of the primary auditory cortex by an increased amphetamine input in 6 out of 15 cases during stimulation by white noise.
Acoustic Stimulation↗
Semiquantitative analyses of dynamic single photon emission computed tomography (SPECT) of the primary auditory cortex.
To date it has not been possible to work out a standard quantification for single photon emission computed tomography (SPECT). Only one mathematical model has received general recognition, but the theoretical preconditions for this model are not fulfilled by iodine-amphetamine kinetics. A practical solution is offered by semiquantitative analysis. We have developed three computer programs for this analysis for perfusion and cerebral function studies of the symmetrically arranged brain.
Adult↗
[Experimental studies of the obliteration of extensive radical ear cavities with a new kind of ceramic granulate].
Modern ear surgery aims at obliterating the extensive radical cavities that remain after removal of a cholesteatoma. A wide variety of techniques have been developed, including working with muscle fascial flaps, cartilage or bone chips; osteoplastic meato-atti++----+-coantrotomy; reconstruction of the posterior auditory duct wall by ceramic dish moulds or homologous cartilage with and without obliteration of the remaining mastoid cavity. The ceramic granulate available for obliteration of the mastoid cavity is responsible for extremely high costs. In an animal experimental study, we investigated the histocompatibility of several new ceramic substances. These new ceramic materials differ especially from the conventional granulate in their implantation behaviour and also in their long-term absorption behaviour, an advantage that enables this ceramic granulate to be used on a broad scale for obliteration of the mastoid cavity and thus the implementation of a largely physiological reconstruction.
Animals↗
[Interactions of external magnetic fields and metallic middle ear implants].
Magnetic resonance imaging is being used increasingly to provide information unobtainable by other imaging techniques. Clinicians have been reluctant to use this technique on patients who have had a stapedectomy because the prosthesis is composed of metal and may move in the electromagnetic fields. We investigated the materials used with respect to their ability to become magnetized and the forces acting on them in a static electromagnetic field, using the SQUID technique. We concluded that there is no danger of a metallic stapedectomy prosthesis becoming displaced by the magnet of a 1.0 or 1.5 T magnetic resonance imaging unit.
Electromagnetic Fields↗
Spect-studies of the brain with stimulation of the auditory cortex.
The radiopharmaceutical N-isopropyl-p-J-Amphetamin (IMP) permits a new approach in the study of cerebral perfusion and function. We advanced the hypothesis for an increased IMP-uptake on auditory cortex during stimulation by white noise. Auditory stimulation activates the auditory cortex. This is marked by an increased IMP-uptake. IMP-uptake by the auditory region on the left side during stimulation on the right ear is another evidence of the crossing of central auditory pathways to the contralateral side.
Acoustic Stimulation↗
Estimating frequency of Kallmann syndrome among hypogonadic and among anosmic patients.
The frequency of Kallmann syndrome (hypogonadotropic hypogonadism and anosmia, HHA) was estimated in patients presenting with hypogonadism and patients with anosmia. Of 791 hypogonadal males 19 had HHA. The frequency of HHA was about 1:25 (n = 8/189) in outpatients questioned about their sense of smell, about 1:50 (n = 11/579) in patients whose blood samples were sent to us for chromosome analysis, and about 1:30 (n = 19/605) in males with hypogonadism and 46,XY chromosomes. The relation of patients with HHA to those with Klinefelter syndrome was 1:10 (n = 19/186). From 24 patients presenting with anosmia we found 1 hitherto undiagnosed case of HHA. The mean age at diagnosis was 24.8 and 24.9 years in our cases and cases from literature, respectively. These data provide evidence that Kallmann syndrome is not infrequent and that most patients remain undiagnosed until the third decade of life. Earlier diagnosis is emphasized by questioning each hypogonadal patient about his sense of smell because therapeutic success seems to be age dependent.
Adolescent↗
[Atypical ultrasound picture of pleomorphic adenoma].
Presentation of an atypical sonomorphology in a case of pleomorphic adenoma of the parotid gland. The tumour was resected and worked up for histological examination. The results emphasise the difficulty of differentiating the subtypes of parotid neoplasms by ultrasonography alone.
Adenoma, Pleomorphic↗