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At least 703 records · Page 39Linked to original sources

PubMed2005

Surgical treatment modalities for lower-extremity iatrogenic nerve lesions.

Thirty-six patients with lower-extremity iatrogenic nerve injury were treated with neurolysis (23), direct nerve coaption (1), and nerve grafting (12) depending on the nature, duration, and degree of nerve injury. Seventeen (74%) of 23 patients presenting with motor nerve injury achieved motor function against resistance. In 24 (80%) of 30 patients with sensory nerve involvement, at least some superficial sensory function was restored. Surgeons should be familiar with clinical and electroneurophysiological tests for early diagnosis of iatrogenic nerve injuries to allow early intervention for maximum nerve recovery.

Adolescent↗

PubMed1999

Amyotrophic lateral sclerosis: Lou Gehrig's disease.

Amyotrophic lateral sclerosis (ALS), commonly called Lou Gehrig's disease, is a progressive neuromuscular condition characterized by weakness, muscle wasting, fasciculations and increased reflexes. Approximately 30,000 Americans currently have the disease. The annual incidence rate is one to two cases per 100,000. The disease is most commonly diagnosed in middle age and affects more men than women. It usually presents with problems in dexterity or gait resulting from muscle weakness. Difficulty in speaking or swallowing is the initial symptom in the bulbar form of the disease. Over a period of months or years, patients with ALS develop severe, progressive muscular weakness and other symptoms caused by loss of function in both upper and lower motor neurons. Sphincter control, sensory function, intellectual abilities and skin integrity are preserved. Patients become completely disabled, often requiring ventilatory support and gastrostomy. Death usually occurs within five years of diagnosis and is attributed to respiratory failure or cachexia. The etiology of the disease is unknown. Current research is focused on abnormalities of neuronal cell metabolism involving glutamate and the role of potential neurotoxins and neurotrophic factors. New drugs are being developed based on these theories. Current management involves aggressive, individualized alleviation of symptoms and complications.

Amyotrophic Lateral Sclerosis↗

PubMedDate not supplied

[Dynamics of the functional state of the brain in acute focal ischemia].

Complex clinical-neurophysiological investigation of 200 patients with cerebral acute focal ischemia was carried out. It included polymodal monitoring of brain functional activity: monitoring of electroencephalography (EEG), compressed spectral array and toposelective mapping of somatosensory evoked potentials, acoustic short-latency evoked potentials, transcranial cortical electric stimulation, electromyo- and electroneuromyography. The development of acute focal cerebral ischemia was shown to be independent of its location, kind and prognosis, accompanied by functional reorganization of whole brain: its supersegmented specialized motor and sensory functional systems, nonspecific formations of segmental peripheral system. These changes in cerebral functional activity can be found already during first hours of ischemia and they remain generalized during 3-5 days.

Brain↗

PubMedDate not supplied

Surgical techniques of anterior decompression and fusion for spinal cord injuries.

Many patients who have static or only slowly improving neurologic deficits and significant compression of the spinal cord and nerve roots can benefit from anterior decompression. The improvement ranges from partial root recovery to very dramatic improvement in upper as well as lower extremities in the patient with quadriparesis. Intrinsic damage or contusion of the spinal cord cannot be reversed by decompression. Patients with motor sparing preoperatively attain a better functional improvement than those patients who have only slight distal sensory function initially. The same can be said of patients with spinal cord injuries treated with surgery, but we believe the ultimate degree of functional recovery of incomplete cord injuries is greater following anterior than posterior decompression when the operation is indicated. An early accurate diagnosis must be made concerning whether a patient has a complete or an incomplete spinal cord injury. The mechanical compressive lesion must be well documented by myelography, laminography, or CAT scan. The patient should not be neurologically harmed by a posterior laminectomy approach to anterior pathology which additionally removes all posterior stability. An anterior compressive block is best removed through an anterior approach.

Cervical Vertebrae↗

PubMedDate not supplied

Preliminary evidence of neurotoxicity associated with eating fish from the Upper St. Lawrence River Lakes.

Pollution of hydrographic basins has affected the flora and fauna that thrive in these aquatic ecosystems, and fish, which constitute an important food resource, often contain a plethora of potentially toxic chemicals. In a major research project on early neurotoxic effects of environmental exposure to manganese among residents in Southwest Quebec, fish consumption from 2 lakes of the Upper St. Lawrence River System, was surveyed as a potential confounding factor. Participants were selected using a random, stratified sampling strategy from lists of the Quebec Health Plan. Following exclusions, 273 men and women between 20-69 years were retained for the present analysis. A total of 103 (37.7%) reported eating fish from the Upper St. Lawrence. Although fisheaters and non-fisheaters were similar for most socio-demographic variables, significantly more fisheaters (65.2%) reported consuming alcoholic beverages as compared to non-fisheaters (42.4%) (Chi Sq. <0.01). To eliminate this possible bias, fisheaters were matched to non-fisheaters for the variables sex, alcohol consumption (never or occasionally vs. regularly), age (+/-5y) and education (+/-2y). A total of 63 matched pairs were thus created. Paired analyses (t-test or Signed Rank) showed that fisheaters had higher levels of blood organic mercury and lead. Analysis of nervous system functions revealed that both groups performed similarly on tests of sensory function, visual memory and recognition, fine motor performance and some motor tests, but fisheaters performed significantly more poorly (p<0.05) on tests requiring cognitive flexibility, word naming, auditory recall, and more complex motor tasks. The profile of deficits is consistent with diminished capacity for information processing. These observations were made within a study that was not specifically designed to examine the effects of fish eating from these two lakes, and the characterization of fish dietary habits has many limitations. Nevertheless, the findings are sufficiently compelling to warrant further studies, since fish from the Upper St. Lawrence Lakes are known to contain multiple neurotoxic substances.

Adult↗

PubMed1999

Motor function in irritable bowel syndrome.

The evidence supporting a role of abnormal motor function in irritable bowel syndrome (IBS) is reviewed. Symptoms commonly present in IBS patients, such as vomiting, diarrhea, constipation or incomplete rectal evacuation, indicate that a motor disorder is implicit as either a primary or secondary disturbance. Physiological studies implicate a disturbance of transit through the small bowel and proximal colon, and abnormal motor responses of the rectum to distention in IBS patients. Intestinal contractions (physiological or 'abnormal') are associated with the sensation of pain, suggesting that these contractions are interactions between abnormal motor and sensory functions in IBS. Therapies aimed at correcting abnormal transit or antispasmodics are the main pharmacological approaches to the relief of IBS, and, although the latter are not always effective in the long term response to treatment, they support the role of dysmotility in IBS. Most novel therapies under trial probably modulate both sensory and motor functions, and are discussed briefly. In summary, the weight of clinical, physiological and pharmacological evidence supports a role of abnormal motility in IBS.

Cholinergic Antagonists↗

PubMed1999

Cortical asymmetries of the human somatosensory hand representation in right- and left-handers.

Hemispheric asymmetry is known for higher brain functions like language and attention. We tested whether such an asymmetry also exists in the representation of elementary sensory functions. Magnetic source imaging was used to compare the cortical somatosensory hand representation in seven right- and five left-handed individuals. In all right-handers the representation of the dominant hand was larger than the contralateral one in the corresponding hemispheres. In contrast, only two out of five left-handers revealed a larger representation of the dominant left hand compared to the right one. In agreement with previous findings on the lateralization of language and attention, there is a strong correlation between handedness and the extent of the cortical hand representation in right-, but not in left-handers. We conclude that a profound functional hemispheric asymmetry also exists in primary sensory cortices.

Adult↗

PubMed1989

Psychometric functions for the discrimination of differences in intensity of Gaussian noise.

A new theory of sensory functioning by Laming predicts how the shape of the psychometric function depends on the context in which a signal is presented. The discrimination of intensities of noise was therefore studied with four different stimulus configurations. In one, observers discriminated between two separate noise samples that differed in intensity. In accordance with the theory, a normal probability integral provided a better fit to each observer's data than either of two other functions: a normal integral with respect to the square of the difference, or a normal integral with respect to the fourth power of the difference. In a second task, observers detected an increment in a continuous noise. For eight out of nine sets of data, a square-law function provided a better fit than either a normal integral or fourth-power function. A third task asked observers to decide which of two noises was amplitude modulated. The predicted square-law function provided the best fit for four out of five observers. In a fourth task, one observer detected an interval of amplitude modulation in a continuous noise. As predicted by the theory, a fourth-power function provided the best fit. In addition, Weber fractions for difference discriminations decreased approximately with the square root of sample duration for durations up to 300 msec, whereas Weber fractions for increment detections decreased approximately directly with duration for durations up to 100 msec. The results are usually in qualitative agreement with the theory and often in quantitative agreement as well.

Adult↗

PubMed2004

The ion channel ASIC1 contributes to visceral but not cutaneous mechanoreceptor function.

BACKGROUND & AIMS: Visceral mechanoreceptors are critical for perceived sensations and autonomic reflex control of gastrointestinal function. However, the molecular mechanisms underlying visceral mechanosensation remain poorly defined. Degenerin/epithelial Na+ channel (DEG/ENaC) family ion channels are candidate mechanosensory molecules, and we hypothesized that they influence visceral mechanosensation. We examined the influence of the DEG/ENaC channel ASIC1 on gastrointestinal mechanosensory function, on gastric emptying, and on fecal output. We also compared its role in gastrointestinal and somatic sensory function. METHODS: To assess the role of ASIC1 we studied wild-type and ASIC1-/- mice. Reverse-transcription polymerase chain reaction (RT-PCR) and Western blot analysis determined expression of ASIC1 messenger RNA and protein in vagal and spinal sensory ganglia. Colonic, gastroesophageal, and cutaneous afferent fibers were characterized by functional subtype and their mechanical stimulus-response relationships were determined. Gastric emptying was determined by using a 13CO2 breath test. Behavioral tests assessed somatic mechanical and thermal sensitivity. RESULTS: ASIC1 was expressed in sensory ganglia and was lost after disruption of the ASIC1 gene. Loss of ASIC1 increased mechanosensitivity in all colonic and gastroesophageal mechanoreceptor subtypes. In addition, ASIC1-/- mice showed almost double the gastric emptying time of wild-type mice. In contrast, loss of ASIC1 did not affect function in any of the 5 types of cutaneous mechanoreceptors, nor did it affect paw withdrawal responses or fecal output. CONCLUSIONS: ASIC1 influences visceral but not cutaneous mechanoreceptor function, suggesting that different mechanisms underlie mechanosensory function in gut and skin. The role of ASIC1 is highlighted by prolonging gastric emptying of a meal in ASIC1-/- animals.

Acid Sensing Ion Channels↗

PubMed1997

Abnormalities of sensory and memory functions in mice lacking Bsg gene.

Basigin is a highly glycosylated transmembrane protein belonging to the immunoglobulin superfamily. We used mutant mice lacking the basigin gene (Bsg) to investigate its involvement in learning and memory. Mutations were generated by the gene targeting method. Various kinds of learning and memory tasks were performed in mutant, hetero and wild type mice. The mutant mice showed worse performance than the wild and hetero mice in the Y-maze task, which assesses short-term memory, and in the water finding task, which examines latent learning, without any motor dysfunction. Moreover, the mutant mice showed less acclimation in the habituation task compared with the wild-type mice. The mutant mice were also more sensitive to electric foot-shock. These findings are consistent with the expression profile of basigin in the central nervous system. Thus, basigin may play an important role in learning and memory as well as in the sensory functions.

Animals↗

PubMed2006

Rapid recovery of segmental neurological function in a tetraplegic patient following transplantation of fetal olfactory bulb-derived cells.

STUDY DESIGN: Case report. OBJECTIVE: Report rapid neurological changes in a complete tetraplegic following a cell injection procedure. SETTING: Beijing, China. METHODS: ASIA/IMSOP neurological scale. Immunostaining of cell cultures. Cellular transplantation to effect functional restoration following spinal cord injury (SCI) has been hypothesized to cause improvements through axonal regeneration, increased plasticity, or axonal remyelination. Several human trials are in preliminary phases. We report a rapid improvement in motor and sensory functions in the segment adjacent to the level of complete SCI within days following cellular transplantation of cultured fetal olfactory bulb-derived cells. The patient was an 18-year-old C3 ASIA A complete tetraplegic 18 months post-injury who had been neurologically stable for more than 6 months. RESULTS: Within 48 h of cell transplantation, the patient improved one ASIA motor grade in the left elbow flexors and began to show right wrist extensor function. Descent of the sensory level occurred within 4 days and then the rate of change slowed. He is now a C5 motor and C4 sensory complete tetraplegic. Cellular cultures prepared in the same facility showed viable human cells that labeled for nestin and GFAP. CONCLUSION: We hypothesize that improved transmission in intact fibers subserving the zone of partial preservation accounts for these early improvements. We emphasize the need for further independent analysis of the outcomes of this and other preliminary cell transplant studies.

Adolescent↗

PubMed1996

Coculture of rat embryonic proprioceptive sensory neurons and myotubes.

With the aim to study the cellular mechanism underlying the process of muscle spindle regeneration, dorsal root ganglia (DRG) neurons derived from 16-day rat embryos were cocultured with developing myotubes in a compartmentalized culture device. To accomplish the selective survival and neurite formation of the proprioceptive subpopulation, the neurotrophic factor, neurotrophin-3, was added to the culture medium. It appeared that the proprioceptive DRG neurons could develop specialized, Ia afferent terminal-like contacts with myotubes. However, these interactions were scarce and did not result in the induction of differentiation of the contacted myotubes into intrafusal fibers as normally occurs during in vivo development. The present coculture setup apparently lacks appropriate regulatory factors essential for the proper matching of sensory axons and intrafusal fiber precursors and the induction of a functional sensory myoneural connection.

Animals↗

PubMed1981

Cellular composition of the rostral pars distalis of the anterior pituitary gland of the alewife, Alosa pseudoharengus, during the spawning run.

The rostral pars distalis of the anterior pituitary gland of the marine alewife, Alosa pseudoharengus, during its annual spawning run to fresh water was examined histologically. The rostral pars distalis is composed of many interconnecting follicles of various sizes. Contrary to earlier reports, the follicular epithelium contains not only prolactin (PRL) cells but corticotropic (ACTH) cell and thyrotropic (TSH) cells (in addition to two nonendocrine cell types). Basally all three endocrine cell types make direct contact with the basement membrane which separates the follicles from the neurohypophysial processes. Apically, however, only the prolactin cells, the largest of the three, protrude into the follicular lumen by means of the small ciliated apical protruberance. All other cellular elements are sealed from the follicular lumen by a layer of covering cells which have properties of transitional epithelial cells. In the follicular epithelium, the slender TSH cells are intercalated between the large conspicuous prolactin cells. The ACTH cells, the smallest of the three endocrine cells, lie in deep invaginations in the basal regions of the individual PRL cells in such a way that on cursory examination they can be mistaken for the nuclei of the latter. Only a small portion of the cellular surface of the ACTH cell escapes the enveloping prolactin cell to make contact with the basement membrane of the follicle. In teleosts, prolactin, ACTH, and TSH have all been implicated in the regulation of hydromineral metabolism and reproductive development. The intimate spatial relation between the three endocrine cells in the alewife rostral pars distalis thus raises the possibility of some functional interactions at the adenohypophysial level, perhaps as an adaptation of this anadromous teleost whose reproductive development and behavior is associated with large changes in ambient salinity. The functional significance of the follicular lumen is discussed together with possible sensory functions of the PRL cells.

Adrenocorticotropic Hormone↗

PubMed1991

Histochemical staining of nerve endings as an aid to free muscle transplantation.

Histochemical staining techniques that identify intact motor nerve fascicles are available to aid free muscle transplantation. Cholinesterase activity of myelinated axons can be identified by Karnovsky and Roots's technique. Axon viability can be assessed based on the presence of axoplasmic enzyme activity. By reacting serial sections for cholinesterase activity and carbonic anhydrase activity, which labels sensory axons, an accurate cross-sectional map of regenerating or functional sensory and motor nerve fibers can be constructed. Resolving the motor and sensory identities of fascicles in a mixed peripheral nerve should lead to more precise coaptation of recipient motor fibers to the motor nerve of the transferred muscle and enhance reinnervation.

Adult↗

PubMed1985

Sequelae of sural nerve biopsies.

Sequelae of sural nerve biopsy were examined in 24 patients. Fourteen subjects reported persisting pain or dysaesthesias for more than one year. In nine patients the symptoms were mild, in five severe. Hypaesthesia of the lateral aspect of the foot was found in 17 out of 18 patients with otherwise normal or only slightly impaired sensory function. In one patient sural nerve biopsy did not cause permanent sensory loss. Pain and dysaesthesia were not significantly related to post-biopsy or generalized hypaesthesia.

Adolescent↗

PubMed1995

Sensory and sympathetic contributions to nerve injury-induced sensory abnormalities in the rat.

Peripheral neuropathy can be associated with a variety of symptoms, including spontaneous unpleasant sensations and pain, as well as increased sensitivity to sensory stimuli. A peripheral neuropathy model involving an L5 spinal nerve lesion in male rats has been used to gain insight into the mechanisms that underlie symptoms that develop after nerve injury. This model was used to study the involvement of sensory fibres, the sympathetic postganglionic neuron and the role of nerve growth factor in the induction and maintenance of altered sensory function in the nerve territory of the intact L4 spinal nerve. Sensory testing was done with calibrated von Frey filaments and a radiant heat apparatus [Hargreaves K. et al. (1988) Pain 32, 77-88] and the occurrence of abnormal spontaneous behaviour was recorded. L5 spinal nerve resection produced increased mechanical and heat sensitivity as well as abnormal spontaneous behaviours. Surgical sympathectomy at the L5 but not at the L4 spinal nerve level alleviated all sensory abnormalities. However, a lesion of preganglionic fibres to the L5 level had no significant effect on sensory abnormalities. Thus, sympathetic postganglionic neurons at the level of spinal nerve injury can contribute to neuropathy symptoms independent of input from preganglionic neurons. Postganglionic sympathetic nerve crush alone led to increased mechanical sensitivity but not to increased heat sensitivity nor to abnormal spontaneous behaviour, further emphasizing the role of sympathetic postganglionic neuron changes for the development of increased mechanical sensitivity. An L5 spinal nerve resection in rats treated neonatally with capsaicin induced increased mechanical sensitivity which was slower in onset and lower in magnitude than that in untreated littermates and was abolished by postganglionic sympathectomy. Nerve growth factor perfused onto the cut L5 spinal nerve also markedly delayed the onset of increased mechanical sensitivity. Two pathophysiological mechanisms leading to central changes may be necessary to produce altered sensations in this model: (i) ongoing activity in C-fibres, independent of sympathetic postganglionic neuron activity and (ii) activity in sensory fibres modulated by a sensory-sympathetic interaction in the injured spinal nerve or dorsal root ganglion. The sympathetic postganglionic neuron contribution is independent of preganglionic sympathetic outflow from the central nervous system, suggesting a novel mechanism by which sympathetic efferent terminals can regulate sensory fibre activity. A contribution of a loss of neurotrophic factors to the sympathetic postganglionic neuron following nerve lesion is also suggested to contribute to the symptoms induced by the spinal nerve lesion.

Animals↗

PubMed2005

Landmarks in the first hundred years of primary (9+0) cilium research.

Primary cilia have had a long research history since 1898, but only in the last few years have investigations become intense. Only a few people took an interest in them until recently, when the consequences of their agenesis or dysfunction suddenly became apparent to all. Their function changed overnight from being speculative to being fully "acknowledged" as sensory, and the consequence of their lacking sensory function(s) led to a bonanza for cell and molecular biologists interested in the impact on clinical disease and disorder. Furthermore, once the medical profession had insight not just into the etiology of an extremely rare syndrome (situs inversus), but into one as prevalent as polycystic kidney disease, furious research activity sprang up in numerous centres, symposium were convened, special sessions arranged, and topical reviews written in all sorts of journals. Without an understanding of the history of research about this organelle, many reviews gave little credit to those who had persevered earlier to make key advances in primary cilium research, and most ignore the wealth of information on them that has relevance to fundamental (cell) biology as well as to medicine. Some of the "landmarks" presented here will hopefully provide a little guidance and a better perspective.

Biology↗

PubMed1991

A fifteen year follow-up of a case of developmental prosopagnosia.

The term developmental prosopagnosia refers to an impairment in the recognition of familiar faces which has been present from birth in the absence of neurological disease or birth complications. The first reported study was by McConachie (1976, Cortex, 12: 76-82) and we report here a fifteen year follow-up on this case (AB). Recently developed theoretical models postulating separate processes involved in face perception and recognition were used to guide the exploration of her functional deficit. Our investigations with AB showed that basic visuo-sensory functions (acuity, contrast sensitivity, colour, etc.) were largely intact. General face perception (e.g. distinguishing between a face and a "nonface") was relatively well preserved. Recognition of familiar faces was severely impaired and she also showed problems with other face processing tasks (e.g. analysis of facial expression) and in object recognition. In object recognition she made errors based on visual similarity, and she had problems identifying exemplars from categories with many visually similar items. In addition, she was very poor at identifying objects or silhouettes from an unusual viewpoint. We conclude that AB has always been poor at constructing an effective internal representation sufficient to permit recognition of items which are visually difficult to discriminate. Therefore, she may not have been able to acquire useable stored representations either, because this deficit has been present since birth. This functional account was supported by subsequent studies which demonstrated a complete absence of covert face recognition.

Agnosia↗