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Results for “sensory function”

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PubMed1999

Primary epineural repair of the ulnar nerve in children.

Transectional nerve injuries are uncommon in children. We report the outcome of 19 children aged < or = 13 years with acute transectional injuries to the ulnar nerves who were treated by primary epineural repair. There were 13 boys and 6 girls with a mean age at the time of injury of 6.7 years (range, 2-12 years). The site of injury was the palm in 4 children, wrist in 10, forearm in 4, and above the elbow in 1. Associated injuries to other structures occurred in 13 children. The mean recovery (Medical Research Council scale) of the first dorsal interosseous muscle was grade 4.0 (range, grade 3-5) and the mean outcome for the abductor digiti minimi was grade 3.9 (range, grade 2-5). The mean static 2-point discrimination was 6 mm (range, 2-20 mm). The mean follow-up period was 50 months (range, 12-103 months). Although proximal injuries (at or above the elbow) had a poorer outcome, satisfactory function of the intrinsic hand muscles still occurred; this finding contrasts to results reported in adults. Similarly, associated injuries to adjacent structures had no impact on ulnar nerve recovery. Primary epineural repair of the acutely transected ulnar nerve leads to a satisfactory recovery in both motor and sensory function in children younger than 13 years.

Arm Injuries↗

PubMed2003

Motivation and neuropsychological test performance following mild head injury.

Effect of motivation on neuropsychological test performance in mild head injury was assessed. Motivation was measured using the Portland Digit RecognitionTest. Three groups were compared: (a) mildhead injury, financial incentives, good motivation; (b) mild head injury, financial incentives, poor motivation; (c) moderate/severe head injury, good motivation. The neuropsychological battery included measures of sensory function, motor function, attention, intelligence, abstract reasoning, and memory. Mild head injury well motivated patients performed significantly better than the other two groups on some tests. Mild head injury poorly motivated individuals and moderate-severe head injury patients were indistinguishable on many tests. Consistent with previous reports, tactile sensory (finger recognition and Fingertip Number Writing Perception) and recognition memory (Rey Auditory Verbal Learning) tasks were identified as clinically useful measures of poor motivation. On these measures mild head injury well motivated examinees performed no better than moderate-severe patients, with both groups superior to mild head injury poorly motivated examinees. Sensitivity and specificity data are reported. Our measures of tactile sensation and verbal recognition memory were more affected by motivation than by the severity of head injury.

Adolescent↗

PubMed1997

NaG: a sodium channel-like mRNA shared by Schwann cells and other neural crest derivatives.

NaG, a member of subfamily 2, was originally characterized as a "glial" sodium channel, and is expressed at high levels in Schwann cells in vivo. However, NaG has also been shown by in situ hybridization to be highly expressed in rat dorsal root ganglion (DRG) neurons, which, like Schwann cells, are neural crest derivatives. In the present study, we used non-isotopic in situ hybridization with a riboprobe for NaG, in conjunction with RT-PCR, to determine whether NaG is expressed in tissues related to the DRG either by neural crest origin or sensory function. We found that the expression of significant levels of NaG mRNA was restricted to derivatives of the neural crest (neurons of DRG, trigeminal ganglion and mesencephalic nucleus of the trigeminal nerve, and Schwann and satellite cells); the absence of NaG from superior cervical ganglion neurons and adrenal medulla chromaffin cells indicates that not all neural crest derived neural elements express NaG. NaG was not observed in sensory neurons (retina, vestibular ganglion, spiral ganglion, olfactory epithelium) that are not of neural crest origin. Our results indicate that NaG mRNA is expressed not only in Schwann cells, but also in a spectrum of neuronal cell types with afferent function of neural crest origin. NaG thus appears to represent a transcript encoding a sodium channel or sodium channel-like protein that is uniquely expressed by both Schwann cells and afferent neurons of neural crest origin.

Animals↗

PubMed2000

Intravenous infusion of 4-AP in chronic spinal cord injured subjects.

STUDY DESIGN: A prospective double blind cross over trial of intravenous 4-Aminopyridine (4-AP). OBJECTIVE: To determine the efficacy of this drug in the treatment of spinal cord injured (SCI) patients for neurologic impairment, pain and spasticity. SETTING: The post anesthesia care unit (PACU) of a tertiary care acute hospital. METHODS: Twelve paraplegic patients were enrolled in a double blind cross over intravenous trial of 4-Aminopyridine (4-AP). Thirty milligrams of 4-AP or placebo were administered over a 2 h period. Patients were serially examined during and after the infusion clinically for pain, sensorimotor function, hypertonicity and motor control using electromyography (EMG). Samples of blood and cerebrospinal fluid (CSF) were also analyzed at similar intervals. RESULTS: Despite penetration of 4-AP into the CSF, no significant differences were noted in the clinical and EMG parameters at the times measured. Individual changes in sensory function were reported by some patients in both the placebo and 4-AP trials, however mean values were not robust. Frequently, patients complained of unpleasant symptoms during the 4-AP infusion. CONCLUSION: The intravenous route may not be the best way to administer this drug as no short term benefits were observed.

4-Aminopyridine↗

PubMed1992

Pharmacologic and neurochemical evidence for the activation of capsaicin-sensitive sensory nerves by lipoxin A4 in guinea pig bronchus.

Exogenous administration of lipoxin A4 (LXA4) to guinea pig isolated bronchus produced contractile effects in a concentration-dependent manner (1, 3, and 6 microM). These responses were potentiated when preparations were previously incubated with thiorphan (10 microM), an inhibitor of tachykinin breakdown, but were significantly depressed when sensory nerves were previously desensitized in vitro by capsaicin (10 microM for 15 min) challenge. Ruthenium red (10 microM for 20 min), a blocker of the cationic channel coupled to the capsaicin receptor, also produced, although in a weaker manner, a reduction in bronchomotor responses elicited by LXA4. On the other hand, preexposure to omega-conotoxin (0.1 microM for 45 min), a blocker of neuronal voltage-dependent Ca2+ channels, did not modify the LXA4 contractile effects. Furthermore, LXA4 (6 microM) superfusion of guinea pig bronchial tissue elicited a significant calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) release that was reduced by capsaicin (10 microM, 30 min) desensitization. Finally, LXA4 (10 microM) was unable to displace [3H]resiniferatoxin binding in dorsal root ganglion of rat and guinea pig. These findings support (1) a role for LXA4 in activating motor sensory function of capsaicin-sensitive nerves; (2) this activation mechanism is marginally ruthenium red-sensitive and omega-conotoxin-resistant; and (3) the interaction does not involve the recognized binding site on the vanilloid receptor. As a whole this study presents LXA4 as an endogenous mediator activating sensory nerves potentially involved in basic mechanisms of airway diseases.

Animals↗

PubMed1999

Laryngopharyngeal sensory discrimination testing and the laryngeal adductor reflex.

Laryngopharyngeal sensory capacity has been determined by endoscopically administering air pulse stimuli to the mucosa innervated by the superior laryngeal nerve and asking the patient if he or she feels the stimulus. A potential shortcoming of this psychophysical testing (PT) procedure is that it is a subjective test, and patients with impaired cognition may not be able to perform the required task. In the search for an objective measure of laryngeal sensory function, we have observed that the laryngeal adductor reflex (LAR) is evoked at stimulus intensities similar to those capable of eliciting the psychophysical, or perceptual, response. The purpose of this study is to determine if the threshold for eliciting the LAR is the same as that of the sensory threshold. A specially designed endoscope was used to present air pulse stimuli (range 0.0 to 10 mm Hg) to the laryngopharynx in 20 healthy subjects and in 80 patients with dysphagia, using both PT and the LAR. The patients had a variety of underlying diagnoses, with stroke and chronic neurologic disease predominating (n = 65). In the control group and in the group of patients with dysphagia, there was no statistically significant difference between the median laryngopharyngeal sensory thresholds whether we used PT or the LAR (p>.05, Wilcoxon signed-rank test). The intraclass correlation for the total sample was .999 (U = .999, L = .998). Since psychophysical and sensorimotor reflex thresholds were not statistically significantly different and the intraclass correlation was close to a perfect correlation, we conclude that the LAR can be used as an objective and accurate clinical method of endoscopically assessing laryngopharyngeal sensory capacity.

Deglutition Disorders↗

PubMed1998

[Sensory disturbance of crossed oral-pedal topography in a case of lateral medullary infarction].

We report a 40-year-old man with hypertension and diabetes mellitus, who had crossed oral-pedal sensory disturbance in lateral medullary infarction. He suddenly developed dysesthesia in the right mount and the left leg. His blood pressure was 150/90 mmHg. Neurological examination showed Horner's sign in the right eye and horizontal nystagmus. Sensory function revealed decreased temperature, hypalgesia and dysesthesia in the right mouth and the left leg. Vibratory and position sense were normal. T1- and T2-weighted images disclosed a low and high signal intensity area in the lateral portion of the right medulla oblongata, respectively. Brain and neck MRA using time-of-flight sequence revealed no obvious abnormal structures. We have diagnosed him as lateral medullary infarction. The unique topography of sensory dysfunction thought to be attributed to a far-lateral lesion in the medulla oblongata. Our patient suggests that lateral medullary infarction causes variable patterns of sensory disturbance. Thus, lateral medullary infarction should be warranted when we encounter patients with miscellaneous distribution of sensory impairment, such as crossed mouth-foot hypalgesia.

Adult↗

PubMed2005

Repair of avulsed ventral nerve roots by direct ventral intraspinal implantation after brachial plexus injury.

Currently, the authors' research confirms that,in humans, communication between the cord and effector muscles can be re-established after multi-ple nerve root avulsion by the implantation of peripheral nerve grafts. Outcomes are still modest,but the possibility of improvement exists. The technique of reimplantation makes it possible to envisage global repair with the possibility of repair of all avulsed regions. The most important factor that could maximize the extent of functional recovery is reducing the time between the injury and corrective surgery: the diagnosis of avulsion within 10 days and reparative surgery within 3 weeks is the objective. This goal will involve a global re-evaluation of how these patients are managed. The problem of the recovery of sensory function (tactile and fine perception and proprioception) warrants further work. It seems likely that methods combining medullary reimplantation with neurotization will be the best way of correcting these lesions of the brachial plexus. In this context, cross-disciplinary collaboration is probably more important than ever. The place that methods based on reimplantation will have in the final picture remains to be seen. The key question is in which patients should medullary reimplantation be attempted and which method should be used. Moreover, medullary reimplantation should be considered as an adjunct to all other surgical options and should not compromise the chance of the latter modalities to be effective.An important point remains: are physicians going to be able to map out all the boundaries of this question in the future?

Brachial Plexus↗

PubMedDate not supplied

Abnormalities of the nervous system in Lyme disease: response to antimicrobial therapy.

Objective measures of neurologic function were used to assess response to treatment in patients with late Lyme borreliosis. Neurophysiologic evidence of peripheral neuropathy was present in 64 of 137 patients tested. Measures of distal axon function (sensory amplitude and conduction velocity, motor terminal latency) were most affected. Repeat studies following 60 patients receiving antimicrobial therapy demonstrated significant improvement in these values. Before and after therapy 17 patients with late Lyme borreliosis and prominent subjective cognitive dysfunction underwent neuropsychologic tests of memory, conceptual ability, concentration, psychomotor function, overlearned intellectual abilities, and mood. Significant abnormalities were evident before treatment; all reversed with antimicrobial therapy. Many patients with this encephalopathy had specific abnormalities revealed by magnetic resonance imaging of the brain and had evidence of intrathecal synthesis of antibody to Borrelia. These findings indicate that late Lyme borreliosis commonly causes nervous system abnormalities that are reversible with appropriate antibiotic therapy.

Anti-Bacterial Agents↗

PubMed2007

Polycystin-2 cation channel function in the human syncytiotrophoblast is regulated by microtubular structures.

Polycystin-2 (PC2), encoded by PKD2, which is one of the genes whose mutations cause polycystic kidney disease, is abundantly produced in the apical domain of the syncytiotrophoblast (hST) of term human placenta. PC2, a TRP-type (TRPP2) non-selective cation channel, is present in primary cilia of renal epithelial cells, a microtubule-based ancillary structure with sensory function. The hST has abundant cytoskeletal structures, and actin filament dynamics regulate PC2 channel function in this epithelium. However, it is expected that the apical hST excludes microtubular structures. Here, we demonstrated by Western blot and immunocytochemical analyses that hST apical vesicles indeed contain microtubule structural components, including tubulin isoforms, acetylated alpha-tubulin, and the kinesin motor proteins KIF3A and KIF3B. PC2 and tubulin were substantially colocalized in hST vesicles. Treatment of hST vesicles with either the microtubular disrupter colchicine (15 microM) or the microtubular stabilizer paclitaxel (taxol, 15 microM) resulted in distinct patterns of microtubular re-organization and PC2 redistribution. We also observed that changes in microtubular dynamics regulate PC2 channel function. Addition of colchicine rapidly inhibited PC2 channel activity in lipid-bilayer reconstituted hST membranes. Addition of either tubulin and GTP, or taxol, however, stimulated PC2 channel activity in control hST membranes. Interestingly, we found that the kinesin motor protein KIF3A was capable of increasing PC2 channel activity in hST. We believe that the data are the first to provide a direct demonstration of a microtubular interaction with PC2 in the hST. This interaction thus plays an important regulatory role in the control of ion transport in the human placenta.

Cations↗

PubMed1999

Influence of HgCl2 on the osphradial multisensory system of Lymnaea stagnalis L.

The osphradial multisensory system of Lymnaea stagnalis L. (Pulmonata, Basommatophora) was used to demonstrate the modulation of chemosensory information both at periphery and central nervous system (CNS) following heavy metal treatments. A semi-intact preparation including osphradium, CNS and the right inner parietal nerve (r.i.p.n.) connecting them was used to record both extracellular activity of nerve and intracellular activity of central neurons receiving information from osphradium. The ion currents of osphradium were recorded using patch-clamp method. The changes in nerve and neuronal activity were expressed by averaging of firing frequency and interspike intervals. The chemosensory function of osphradium was shown by application of L-aspartate, urea, saccharose and stagnant water to its surface. The central neurons reacting to the stimulation ofosphradium were located to visceral, right parietal, pedal and cerebral ganglia of Lymnaea. Both the acute and chronic treatments with HgCl2 damaged the sensory function of osphradium traced on the flow of information from periphery to central neurons. At the same time, mercury chloride modified the synaptic connections of respiratory pattern generators as well as the Ca- and K-dependent ion currents of osphradial neurons. The results proved the multisensory role of osphradium sensing the alterations in the environment and its usefulness in monitoring the effects of pollutants at various level of regulation from chemosensory epithelium to CNS.

Animals↗

PubMedDate not supplied

[Effect of extremely high-frequency electromagnetic radiation on the function of skin sensory endings].

The specific features of skin receptor function on the sole of the hind limb of an albino rat were studied in an acute experiment. Impulse activity recorded from the solitary fibres of the tibial nerve showed that receptor units (RU) responded to mechanical stimulation of the skin. Irradiation of the skin surface by low-intensity millimeter band electromagnetic field (frequencies of 55.61 and 73 GHz) in the zone of the RU led to diminution of RU sensitivity to the mechanical stimulus. One half of the RU ceased to respond to the mechanical stimulation 25 minutes after irradiation. The other half continued responding to stimulation even after 35 minutes of irradiation, but the character of the RU response was significantly changed. A strict frequency-resonance dependence of the biological effects was revealed. It is concluded that electromagnetic radiation has a modulatory-inhibiting effect on the skin RU. The authors suggest a possible mechanism of realization of the effect of electromagnetic radiation of extremely high-frequencies and low power on the skin receptor function.

Animals↗

PubMedDate not supplied

A study of sensory recovery following carpal tunnel release.

The purpose of this study was to define the testing parameters that are most sensitive to sensory loss in carpal tunnel syndrome and then to track recovery of these sensations postoperatively. Two dozen patients underwent standard nerve decompression and were subsequently re-evaluated at six weeks, three months, and six months. The test battery included provocative maneuvers, light-touch threshold determined by manually applied monofilaments and skin indentation with the Automated Tactile Tester (ATT), manual two-point discrimination, manual high-frequency vibration and ATT low-frequency vibration, and ATT warmth detection. The most sensitive indicators of sensory abnormality were the ATT low-frequency vibration and skin indentation tests. Responses to all but these two tests returned to normal within two months postoperatively. The ATT indentation and vibration tests showed continual improvement over the study period, returning to nearly normal values by six months. Recommendations concerning the use of automated methods for testing sensory function are made in light of these findings.

Adult↗

PubMed2006

Sensory deficit in the donor hand after harvest of radial forearm free flaps.

Fifty patients undergoing radial forearm free flap reconstruction of head and neck defects were examined to find out the extent of sensory defect at the donor site. Flaps (mean length 6 cm, range 4-9) and mean width 4.7 cm (range 3.5-7) were raised. Of the 50 patients 38 (76%) were aware of some sensory loss over the radial distribution in the donor hand. There was objective evidence of a reduction in at least one sensory function in 32 of these patients (84%). The mean affected area was 44.3 cm(2) (range 6-125). The mean length of the affected area was 11.3 cm (range 4.3-12.1) and the mean width 5.1cm (range 2.1-8.4). Of the 12 patients (24%) who reported no feeling of sensory loss all modalities of sensation were preserved in 11 (92%).

Aged↗

PubMed2005

Phenotypic analysis of mice deficient in the type 2 galanin receptor (GALR2).

Galanin is a neuropeptide implicated in the regulation of feeding, reproduction, cognition, nociception, and seizure susceptibility. There are three known galanin receptor (GALR) subtypes (GALR1, GALR2, and GALR3), which bind to galanin with different affinities and have their own unique distributions, signaling mechanisms, and putative functions in the brain and peripheral nervous system. To gain further insight into the possible physiological significance of GALR2, we created mutant mice that were deficient in GALR2 and compared their phenotype to that of wild-type (WT) littermate or age-matched controls, with respect to basic motor and sensory function, feeding behavior, reproduction, mood, learning and memory, and seizure susceptibility. Phenotypic analysis revealed that animals bearing a deletion of GALR2 did not differ significantly from their WT controls in any of the measured variables. We conclude that either GALR2 plays no role in these physiological functions or through redundancy or compensation these mutant animals can adapt to the congenital absence of GALR2. It is also conceivable that GALR2 plays only a subtle role in some of these functions and that the impact of its loss could not be detected by the analytical procedures used here.

Animals↗

PubMed1989

Sensory and motor functions of the superior parietal cortex of the monkey as revealed by single-neuron recordings.

From the literature on the functional role of the superior parietal cortex, it can be seen that this cortical area has been attributed both sensory and motor functions, as demonstrated by anatomical and lesion studies. Single-unit recordings in behaving monkeys have equally been interpreted as demonstrating these two functions. However, the results of recent experiments using this technique suggest that area 5 may function in the transformation of sensory activity into motor activity.

Animals↗

PubMed2002

Manipulating desaturase activities in transgenic crop plants.

The properties of edible vegetable oils are determined to a large extent by the relative content of the triacylglycerol fatty acids. The degree of saturation of these fatty acids can determine the functional, sensory and nutritional value of the oil. One method of altering the unsaturated fatty acid content of oilseeds is by manipulating the expression of desaturase genes of these plants. Manipulating the expression of desaturase genes in transgenic crops such as soybean, maize and canola (oilseed rape) has led to oils with improved functionality and nutrition. We have also been successful in manipulating the fatty acid content of domesticated oilseed plants by expressing heterologous desaturase and desaturase-related genes from exotic plants that produce unusual fatty acids. We have discovered that metabolic regulation, the number of genetic alleles that encode fatty acid biosynthetic enzymes, and the movement of fatty acids between complex lipids in the cell, all have a role in determining the effect of a transgene on the phenotype of the crop plant and the fatty acid composition of its seed oil.

Biotechnology↗

PubMed1989

Anatomy and neurophysiology of the taste system in aged animals.

In summary, the recent data from quantitative studies of taste buds in old humans, rhesus monkeys, and rats complement neurophysiological data on taste responses from aged rats and lead to the general conclusion that the peripheral taste system is maintained structurally and functionally across the life span. Although some statistically significant differences were observed, the magnitude of these differences would not lead one to predict altered taste preferences or feeding behavior in old animals. The robust nature of the peripheral sense of taste in old age appears to be in sharp contrast to other sensory systems. Not only do receptors alter with age, but accessory organs, such as the lens in the visual system, also alter structurally so that sensory function is compromised. One factor contributing to maintenance of the receptor organ of taste bud and papilla is the turnover and replacement of taste bud cells and surrounding epithelial cells. Recent studies in aged mice indicate no differences in turnover time in epithelial mucosa lining the mouth. There are no data on turnover time, however, for taste bud cells or for gustatory papilla epithelium in old animals. Alterations in taste bud cell or membrane receptor turnover could affect function. In other cell types and receptors, age-related differences in membrane lipids, proteins, and fluidity characteristics are reported. Membrane changes such as these are proposed to account for age-related differences in response properties of the system of cardiac muscarinic receptors, a system in which density of receptors does not alter. The small, but statistically significant, differences in neurophysiological responses to taste stimuli from the chorda tympani nerve might well relate to age-related differences in membrane receptors. Not only is there an absence of data on turnover time or membrane characteristics for taste bud cells in old age, but there are no observations on the ultrastructure of taste buds in old animals. The taste bud is a complex structure, composed of many cells and different cell types, with a specific orientation and access to the oral cavity via the taste pore, and with extensive associations with the innervating afferent fibers. Ultrastructural observations could provide information on changes in synapses and other nerve/cell contacts--in microvilli and taste pore structure, and in numbers of various cell types within the bud. Such data will be essential to understanding the nature and extent of age-related alterations in the taste system.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗