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Biomedical subjects

O Appenzeller

Publications and source records attributed to O Appenzeller.

At least 55 records · Page 3Linked to original sources
PubMed1988

Amantadine, fatigue, and multiple sclerosis.

In a double-blind placebo-controlled crossover study of ten patients with multiple sclerosis, we found amantadine hydrochloride therapy to be effective in improving fatigability in six. Administration of the drug was associated with significantly higher levels of beta-endorphin-beta-lipotropin and responders had significantly higher levels than nonresponders. Lactate levels were significantly higher and pyruvate levels lower in nonresponders. Amantadine given for fatigue to patients with multiple sclerosis is associated with measurable changes in levels of metabolites and peptides in the circulation.

Amantadine↗
PubMed1986

Adrenergic innervation of vasa and nervi nervorum of optic, sciatic, vagus and sympathetic nerve trunks in normal and streptozotocin-diabetic rats.

Adrenergic nerves were studied in nervi nervorum and perivascular nerve plexus of vasa nervorum in whole-mount nerve sheath preparations of optic, sciatic and vagus nerves and in the paravertebral sympathetic chain in normal and streptozotocin-treated diabetic rats. A substantial or complete loss of fluorescent adrenergic fibres around blood vessels in the optic nerves was observed 8 weeks after induction of diabetes. This was in marked contrast to the increase in perivascular adrenergic fibres in the sciatic, vagus and sympathetic chain nerve trunks of the same animals at the same time. Assays of noradrenaline levels in whole nerve segments also showed that they were not biochemically detectable in the optic nerves but were significantly higher in the vagus of diabetic animals (P less than 0.05). There was also an increase in numbers of mast cells in the vicinity of vasa nervorum of diabetic nerves.

Adrenergic Fibers↗
PubMed1986

Neurofibromatosis xenografts. Contribution to pathogenesis.

We transplanted Schwann cells of 3 patients with neurofibromatosis from neurofibromas, sural nerve, and from a malignant schwannoma into sciatic nerves of immunoincompetent mice. Three and six months later, the grafts and distal nerve segments contained normal myelinated fibers. After rendering host animals immune competent again, neurofibroma and malignant schwannoma Schwann cells were rejected, but grafts retained normally myelinated fibers indicating that these were of mouse origin. Sural nerve Schwann cells from a neurofibromatosis patient were rejected also leaving naked axons in the grafted segments showing that human Schwann cells from the sural nerve of one patient had invested and myelinated the regenerating mouse axons. The nature of putative signals passing between axons and Schwann cells might be elucidated by the combination of human and animal cells in immunoincompetent host nerves. Hypothetical signals for myelination of mouse axons were normally received by sural nerve Schwann cells of a patient with neurofibromatosis, but not by Schwann cells from neurofibromas or malignant schwannomas.

Animals↗
PubMed1984

The nerves to blood vessels supplying blood to nerves: the innervation of vasa nervorum.

Noradrenergic, serotoninergic and peptidergic nerves have been demonstrated in perivascular plexuses of vasa nervorum of sympathetic, parasympathetic and somatic nerve trunks. 5-Hydroxytryptamine-, vasoactive intestinal polypeptide- and substance P-containing fibers were found by immunohistochemistry to variable extents in whole mounts of the epineurium of sciatic, vagus and paravertebral sympathetic chains of rabbits. Innervation increased with age. This suggests an hitherto unsuspected role for these vasoactive substances in normal blood flow to nerves and in the genesis of experimental and human neuropathies.

Age Factors↗
PubMed1984

Headache.

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Adolescent↗
PubMed1983

Time course of blood nerve barrier reconstitution after sectioning: implications for xenograft studies.

The time course of blood-nerve barrier recovery in mouse nerves was studied after proximal and distal segmental sciatic sections. Transfer constants for uptake of isotopically labeled sucrose and urea were determined. Sectioned segments were examined ultrastructurally. Marked alterations in isotope uptake for 2 months with gradual restoration of blood-nerve barrier by 6 months was found. Ultrastructure of sectioned segments showed increased numbers of perineurial compartments. Human nerve xenografts to immunosuppressed animals remain hypomyelinated for 6 months which may be related to damage to the blood-nerve barrier.

Animals↗
PubMed1981

Cluster headache. Ultrastructural aspects and pathogenetic mechanisms.

The skin of both temples was examined ultrastructurally in six patients with cluster headaches and in three controls. An increased number of mast cells were present in the patients irrespective of whether they were in a cluster period or in a quiescent phase. The mast cells were found perivascularly and in the vicinity of cutaneous nerves in the patients, whereas they were predominantly found in perivascular areas in controls. Mast cell degranulation was not more prominent on the side of the pain and occasional degranulated mast cells were found in controls. These findings are consistent with the hypothesis that cluster headache is due to an axonal reflex in the trigeminal system, initiated perhaps by latent viral infection of IgE activation of mast cells.

Adult↗
PubMed1980

Pure axonal neuropathy: nerve xenografts and clinicopathological study of a family with peripheral neuropathy, hereditary ataxia, focal necrotizing encephalopathy, and spongy degeneration of brain.

Three family members had the unusual combination of severe peripheral neuropathy, atypical hereditary ataxia, spongy degeneration of cerbral hemispheres, and cerebellar and brainstem foci of necrotizing encephalopathy, proved pathologically in one autopsied case. A sural nerve from a patient, devoid of myelinated fibers, was transplanted into thymectomized, lethally irradiated, and bone marrow reconstituted adult mice. A normal number of myelinated fibers was present in the grafts eleven weeks later. Eighteen weeks after grafting, mice were reconstituted with syngeneic thymus to return immunocompetence. Schwann cells in the graft were rejected and axons became totally denuded of myelin after thymus reconstitution. The peripheral neuropathy is thus due to axonal disease since human Schwann cells were capable of normally myelinating regenerating mouse axons. A puzzling feature after rejection was the absence of myelin debris containing macrophages in the grafts. It is suggested that part of the rejection process in this model is mediated by antibody rather than by cellular mechanisms.

Adolescent↗
PubMed1980

Headache.

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Brain Diseases↗
PubMed1979

Experimental autonomic neuropathy: ultrastructure and immunohistochemical study of a disorder of reflex vasomotor function.

Vasomotor function in ear vessels of rabbits was tested in animals with experimental autonomic neuropathy (EAUN), experimental allergic neuritis (EAN), and controls. Reflex vasodilatation was impaired in animals with EAUN but not in EAN or control rabbits. Ultrastructural examination of paravertebral sympathetic chain, perivascular nerves, and perivascular tissue showed similar changes in all animals differing in degree only. Occasional lymphocytes were seen in paravertebral chains of controls but large numbers of lymphocytes and macrophages occurred in EAUN and EAN. No active destruction of myelinated or unmyelinated fibers could be seen. Perivascular nerves showed similar cellular infiltrates and basophils were found in perivascular spaces of ear vessels which were most abundant in animals with EAUN. Fibre-size spectra analysis of unmyelinated fibres in the paravertebral sympathetic chain showed a shift to the left suggesting regeneration of unmyelinated axons in both EAN and EAUN. No specific immunofluorescence against neuronal components could be demonstrated in sensitized animals. It is concluded that the functional disturbance of reflex vasomotion in EAUN is not accompanied by specific ultrastructural lesions nor could neuronal components be immunologically implicated in the disorder. Regeneration of unmyelinated axons and recovery of function after some weeks together with abundance of basophils in perivascular tissue of sensitized animals, suggests that a localized inflammation may have occurred, the basophils interfacing between foreign antigens, the serum cascade systems, and other inflammatory cells. The usefulness of EAUN as a model for acute pandysautonomia in man remains to be determined.

Animals↗