Reflux esophagitis and H. pylori.
Explore the source record for details and available documents.
Duodenal Ulcer↗
Biomedical subjects
E Verdú
Publications and source records attributed to E Verdú.
Influence of physical parameters of nerve chambers on peripheral nerve regeneration and reinnervation.
We compared reinnervation of target organs after sciatic nerve section leaving gaps of 2, 4, 6, or 8 mm or gaps repaired with silicone tubes in different groups of mice. Functional reinnervation was assessed by noninvasive methods to determine recovery of sweating, nociceptive, and muscular functions in the hindpaw repeatedly during 3 months postoperation. The increase of gap length between nerve stumps delayed the beginning and reduced the degree of functional recovery achieved either with or without repair. When lesions were left unrepaired, functional reinnervation was only noticeable with a 2-mm gap and practically absent with longer gaps. With tube repair, reinnervation started earlier and achieved higher values than in the corresponding unrepaired groups. Tubulization was most effective with 4-mm gaps and comparatively less with shorter and longer gaps. With 4-mm gaps, recovery was higher when the silicone tube had a cross-sectional area 2.5 times that of the sciatic nerve than with narrower or wider tubes and when the wall was the thinnest available. In all cases muscle reinnervation showed a lower progression than sweating and nociceptive recovery.
Action Potentials↗
The effect of aging on efferent nerve fibers regeneration in mice.
This study evaluates the influence of aging on nerve regeneration and reinnervation of target organs in mice aged 2, 6, 9, 12, 18 and 24 months. In animals of each age group the sciatic nerve was subjected to crush, section or section and suture. Reinnervation of plantar muscles and sweat glands (SG) was evaluated over three months after operation by functional methods. Reappearance of SG secretion and motor responses occurred slightly earlier in young than older mice. The degree of motor and sudomotor reinnervation, with respect to preoperative control values, was also significantly higher in young than old animals. The differences were more pronounced after 12 months of age. The degree of recovery progressively decreased with the severity of the lesion, differences being more marked in older mice. Neurorraphy improved recovery, comparatively more in older than in young mice. These results indicate that, after injuries of peripheral nerves, axonal regeneration and reinnervation are maintained throughout life, but tend to be more delayed and slightly less effective with aging.
Aging↗
Functional sudomotor responses to cholinergic agonists and antagonists in the mouse.
This study evaluates the functional activity of the mouse sweat glands in response to cholinergic agonists and antagonists using the silicone imprint technique. In intact mice the response to acetylcholine, methacholine and pilocarpine did not differ significantly from control saline injection, indicating that immobilization induces high levels of sweating, masking the effects of cholinergic stimulation. Plantar emotional sweating was completely abolished by local anesthesia at the ankle. Under these conditions, administration of acetylcholine only provoked detectable sweating when injected locally into the sole skin. Methacholine activated an increasing number of sweat glands in a dose-dependent manner between 0.5 and 10 mg/kg; the response was maximal after 5-10 min of administration and decreased subsequently. With pilocarpine the maximum number of reactive sweat glands was observed at a dose of 2.5 mg/kg. The response was stable for 45 min with doses 2.5 and 5 mg/kg, but decreased exponentially with higher doses. The subtype of sweat gland muscarinic receptor was characterized by determining the inhibitory effect of different cholinergic antagonists on pilocarpine response. Atropine and 4-DAMP were equally potent inhibitors, showing a dose-related effect from 0.05 mg/kg. Pirenzepine only showed inhibitory effects with doses 10-times higher, whereas gallamine and hexamethonium did not induce inhibition at any of the doses tested. These findings suggest that the mouse eccrine sweat gland muscarinic receptors are predominantly M3.
Animals↗
Innervation of cutaneous structures in the mouse hind paw: a confocal microscopy immunohistochemical study.
The normal innervation of structures in mouse foot pads was investigated with immunohistochemistry and confocal microscopy. Nerves were visualized by incubating Zamboni fixed, thick, frozen sections with antibodies to protein gene product 9.5 (PGP 9.5), vasoactive intestinal peptide, substance P, calcitonin gene-related peptide, and protein zero. The antibodies were localized using cyanine 3.18 labeled anti-rabbit gamma globulin. PGP 9.5 immunolocalization showed dense nerve bundles at the base of the foot pad with branches to larger blood vessels, sweat glands and epidermis. Sweat gland tubules were surrounded by numerous sudomotor axons; single fibers accompanied the sweat duct toward the skin's surface. Nerve bundles containing myelinated and unmyelinated axons ran through and around the centrally located sweat gland cluster to end in free nerve endings and Meissner's-like corpuscles at the apex of the foot pad. Other bundles running parallel to the epidermis gave arcuate branches that supplied epidermis on the sides of the pads with a rich nerve network, principally with free nerve endings that often reached the most superficial cell layers of epidermis. Calcitonin gene-related peptide-immunoreactive (-ir) nerves were distributed to dermis and epidermis in lower density than PGP 9.5-ir fibers. Substance P-ir fibers were less numerous; most terminated as free endings in deeper layers of epidermis. Vasoactive intestinal peptide-ir nerves almost exclusively innervated sweat glands, ducts and blood vessels, but not epidermis. The mouse hind paw has potential to serve as a model system for investigations of functional and morphological changes that affect peripheral and autonomic nerves under diverse experimental conditions.
Animals↗
Effects of dizocilpine on autotomy behavior after nerve section in mice.
The effects of acute administration of dizocilpine (MK-801) at different perioperative times on autotomy behavior after sciatic and saphenous nerve transection were studied in the mouse. Control mice developed a severe self-mutilating behavior starting 1-3 days postoperation and reaching a maximum by 11 days. Mice injected with a single dose of dizocilpine (0.4 mg/kg i.p.) before operation, the 1st or 3rd postoperative day autotomized significantly less than controls. An 1-wk treatment with the same dose once a day did not show further benefit. A single administration of dizocilpine the 5th day after surgery slightly halted further progression of autotomy. Dizocilpine did not have any deleterious effect on normal peripheral nerve function. These results suggest that NMDA receptor blockade prevents development of hyperalgesia and neuropathic pain after peripheral nerve injuries but only when it is administered before or during the first 3 days after injury.
Animals↗
Comparison of regenerative and reinnervating capabilities of different functional types of nerve fibers.
Functional reinnervation of sweat glands (SGs), skin, and muscle in the mouse paw after sciatic nerve lesions was evaluated to allow comparisons of the regeneration efficiency of different functional types of nerve fibers. In four groups of mice the sciatic nerve was crushed, sectioned, and left unrepaired or repaired by suture or tubulization. Reappearance of SG secretion and pinprick responses occurred slightly earlier than recordings of compound muscle and nerve action potentials in all groups. The degree of reinnervation, with respect to preoperative control values, of SGs and skin nociceptors was higher than the amplitude of the action potentials, mainly when the nerve injury was severe. The chances for recovery progressively decreased with the severity of the lesion, affecting the larger nerve fibers most. These results indicate that, after injuries of peripheral nerves, all types of nerve fibers are able to regenerate in the mouse, although small size fibers (sudomotor and nociceptive) allow for a higher degree of functional recovery than large myelinated fibers (skeletomotor and sensory).
Animals↗
Abnormalities of sympathetic sudomotor function in experimental acrylamide neuropathy.
The possible involvement of sympathetic sudomotor function by acrylamide intoxication was investigated in the mouse, and compared with nerve conduction studies and global motor tests. Acrylamide (40 mg/kg, 3 days per week, 8 weeks) was given per os to a group of mice (A1). Their motor ability to stand on the rotarod was impaired from day 11, reaching a minimum between 46 and 60 days. The number of pilocarpine reactive sweat glands (SG), evaluated by the silicone mold technique, was similar to controls at 40 days and slightly decreased at 54 days. Another group of mice (A2), given acrylamide at a higher dose (50 mg/kg, 5 days per week, 5 weeks), showed abnormalities on the rotarod by 11 days, a progressive decrease of muscle action potential (CMAP) amplitude, and significantly decreased number of reactive SG from 15 days, with respect to controls. Comparatively, sudomotor dysfunction was milder and appeared later in time than alphamotor involvement, being noticeable only after severe poisoning. The decrease in SG response is attributable to damage by acrylamide intoxication of postganglionic sudomotor nerve fibers, which are unmyelinated sympathetic efferents.
Acrylamides↗
Functional changes of the peripheral nervous system with aging in the mouse.
The influence of aging on peripheral nerve and target organ function was investigated in six groups of mice aged 2, 6, 9, 12, 18, and 24 months. Sudomotor, motor, and sensory functions mediated by the sciatic nerve were evaluated by silicone imprints, electrophysiological recordings and pinprick test from the distal hindpaw. Nerve conduction was also studied in the caudal nerves. The results showed that the number of sweat glands reactive to pilocarpine does not change significantly with aging, but the size of the sweat droplets is smaller in aged mice than in young mice. The amplitude of muscle and nerve action potentials evoked by stimulation of sciatic and caudal nerves decreased progressively from 2 to 24 months, while the latencies decreased from 2 to 6 months, remained unchanged until 12 months and increased thereafter. All the animals of the six groups studied showed positive, indistinguishable responses to pinprick. These results indicate that neurophysiological responses mediated by large diameter nerve fibers deteriorated with age, while those dependent of small fibers were preserved.
Aging↗
[Methodological considerations concerning peripheral nerve morphometry].
Morphometric studies of the peripheral nerve often present widely varying results which, in part at least, may be attributed to the different methodologies used. Two questions may be of importance with regard to the reliability of such results: the preselection of fibres according to their morphology and the method used in quantifying observations. In this work a morphological study was carried out on the myelinated fibres of the sciatic nerve of a rat in order to evaluate fibre selection criteria. A morphometric analysis was also performed using manual measurements, image digitalisation and surveying, and automatic image analysis. It was shown that morphological variability of transverse section fibres is considerable and that, really, the proportion of circular fibres with homogeneous compact myelin is only 50 to 70%, from which we can conclude that the selection of fibres carried out in some studies wishing to eliminate abnormal fibres is somewhat exaggerated. By analysing the fibres using various methods significant differences appear, some due to the fact that distinct methods may be used to calculate the same parameters in a different way. The most reliable parameters would appear to be those which do not depend on the shape of the fibres and those which automatic or semiautomatic methods can calculate directly such as areas and perimeters. In any case quantifying methods seem hardly discriminatory and the differences between methods disappear if analyses are carried out using random samples. Preselection of fibres appears unnecessary in this context as in no case are the results altered. Finally we suggest finishing quantitative analyses with qualitative studies which would permit getting more information especially useful in cases of ageing, regeneration or pathological studies.
Aging↗
[Degeneration and regeneration of the peripheral nervous system with aging].
Clinical and experimental studies have shown that with aging there appear neurological changes which affect both the Central Nervous System (CNS) as well as the Peripheral Nervous System (PNS), bringing about a series of cognitive, sensory and physical disabilities in older people. Nerve lesions also cause disability. The basic mechanisms which begin with lesioned neurons have proved an interesting field of study for many neuroscientists since as far back as the mid-nineteenth century. However the influence of age on these postlesion neuronal processes has not aroused the same level of interest even though many authors have, out of curiosity, published reports of changes which take place in regenerative neurons as a result of age. The progressive increase in the aged population in industrialised nations warrants a detailed study into the influence of age on such neuronal processes. The PNS, due to its accessibility and greater regenerative potential vis-à-vis the CNS, may be a good model for this purpose. From results obtained by both other authors and ourselves it is clear that aging causes a decline in the regenerative abilities of peripheral nerve fibres. Functional recovery is not only slowed down but also decreases with age. The number of regenerative axons and their capacity for end sprouting, together with the biosynthesis and transport of new materials in the regenerative neurons, as well as the proliferation and synthesis of trophic factors by Schwann cells also decay. All of this leads to the fact that the regenerative capacity of nerve fibres is lesser with age, and that functional disabilities after a lesion are greater in older than in younger people.
Aging↗