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The effects of sensory denervation on the responses of the rabbit eye to prostaglandin E1, bradykinin and substance P.

1 Six to eight days after diathermic destruction of the fifth cranial nerve in the rabbit, the ocular hypertensive and miotic responses to intracameral administration of capsaicin, bradykinin, and prostaglandin E1 were greatly reduced or completely abolished. The response to substance P was not abolished. 2 A response could still be obtained to chemical irritants 36 h after coagulation of the nerve and it is deduced that manifestation of the response is dependent upon functional sensory nerve terminals, and is independent of central connections. 3 It is suggested that prostaglandin E1 and bradykinin act directly upon the sensory nerve endings and that propagation of the response is augmented by axon reflex. 4 In view of the ability of substance P to induce miosis in the denervated eyes, it is presumed that its actions are not mediated via sensory nerves. 5 It is considered possible that the mediator(s) released from sensory nerve endings after chemical irritation or antidromic stimulation may act in the same way as substance P with regard to the miotic effect. 6 Synthetic substance P will only produce ocular hypertension in doses which induce a maximal miotic response. This may either be a question of access or a partial resemblance to the endogenous mediator.

Animals↗

Management of irritable bowel syndrome.

Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders. The prevalence rate is 10-20% and women have a higher prevalence. IBS adversely affects quality of life and is associated with health care use and costs. IBS comprises a group of functional bowel disorders in which abdominal discomfort or pain is associated with defecation or a change in bowel habit, and with features of disordered defecation. The consensus definition and criteria for IBS have been formalized in the "Rome II criteria". Food, psychiatric disorders, and gastroenteritis are risk factors for developing IBS. The mechanism in IBS involves biopsychosocial disorders; psychosocial factors, altered motility, and heightened sensory function. Brain-gut interaction is the most important in understanding the pathophysiology of IBS. Effective management requires an effective physician-patient relationship. Dietary treatment, lifestyle therapy, behavioral therapy, and pharmacologic therapy play a major role in treating IBS. Calcium polycarbophil can benefit IBS patients with constipation or alternating diarrhea and constipation.

Adolescent↗

Sensory perception and neuroanatomical structures in normal and grafted skin of burn survivors.

BACKGROUND: This study compared the neural structures found in grafted skin of burn survivors with neural structures found in site-matched normal skin and correlated these structures with psychophysical measures of sensation. METHODS: Fifteen skin-grafted male burn survivors (47.7+/-10.4 years old) with deep partial- or full-thickness thermal burn injuries covering an average of 11+/-5.6% of their total body surface and with normal skin at a matching, unburned, contralateral site were recruited into this study. Threshold determinations and magnitude estimations for touch, cold, warmth and heat-pain were performed at sites with grafted and normal skin, using Semmes-Weinstein monofilaments and the Medoc TSA 2001 thermal stimulator. Skin biopsies from both the grafted and normal sites were stained with antibodies for protein gene product 9.5 (PGP) and neurofilament 200 kDa. Nerve fibers in the epidermis and nerve fibers or bundles of nerve fibers in the superficial and deep dermis as well as innervated blood vessels, hair follicles and sweat glands were counted. RESULTS: On average, the data were collected 43.1+/-10.4 months after grafting. When thresholds on grafted skin were compared to thresholds on normal skin, they showed elevated sensory thresholds [touch (p<0.003), cold (p<0.031), warmth (p<0.009)]. Magnitude estimates of touch, cold and warmth differed on the two sides with sensations elicited from grafts being smaller than those from normal skin. Heat-pain thresholds and heat-pain magnitude estimations were not statistically different on the two sites. By comparison to the normal side, and consistent with the attenuated sensory functions of the grafts, counts of neural structures showed a reduction in innervation density; PGP-immunoreactive nerve fibers/bundles were reduced in grafted epidermis (p<0.026) and superficial dermis (p<0.001). The numbers of sweat glands (p<0.006) and hair follicles (p<0.001) were also reduced. The number of innervated blood vessels did not differ significantly on the two sides. There were significant correlations between sensory thresholds and the neuroanatomical variables: thresholds of cold and touch were correlated with the number of sweat glands in both grafted and normal skin (r2=0.56 and 0.50, respectively; p<0.001), while warmth thresholds were significantly correlated with the number of innervated blood vessels in grafted skin (r2=0.62, p<0.001). Encapsulated mechanoreceptors were not encountered in this study of hairy skin. CONCLUSIONS: Touch, cold and warmth thresholds and magnitude estimations do not return to normal levels after skin grafting in burn survivors. The elevation of thresholds and reduction of sensory intensity is accompanied by a general decrease in the density of nerve terminals. The lack, or numerical reduction, of sweat glands and innervated blood vessels was also indicative of diminished sensation on grafted skin.

Adult↗

Visceral inputs to neurons in the anterior hypothalamus including those that project to the periaqueductal gray: a functional anatomical and electrophysiological study.

The present study was designed to examine peripheral, in particular noxious visceral, inputs to neurons in the hypothalamus that project to the midbrain periaqueductal gray. The induction of Fos protein was used to localize hypothalamic neurons that were activated by noxious visceral stimulation. This was combined with retrograde transport of fluorescent latex microspheres from identified "pressor" and "depressor" sites in the dorsolateral/lateral or ventrolateral columns of the periaqueductal gray. A second series of electrophysiological experiments examined the receptive field characteristics, including the incidence of viscerosomatic convergence, of neurons in the ventral part of the anterior hypothalamus. Noxious visceral stimulation (intraperitoneal acetic acid) induced Fos-like immunoreactivity in significantly more neurons in the hypothalamus than control stimuli (intraperitoneal saline and intravenous phenylephrine). Particularly high numbers of Fos-positive neurons were found in the paraventricular nucleus, the supraoptic nucleus and ventral regions of the anterior hypothalamus. When combined with retrograde tracing from "depressor" sites in the ventrolateral periaqueductal gray, the highest numbers of double-labelled neurons were localized in the paraventricular nucleus and the lateral area of the anterior hypothalamus. However, the regions that contained the greatest proportions of Fos-positive neurons that projected to "depressor" sites in the ventrolateral periaqueductal gray were the lateral area of the anterior hypothalamus and its rostral extension, the lateral preoptic area. Fewer double-labelled neurons were localized in the hypothalamus after retrograde transport from sites in the dorsolateral/lateral periaqueductal gray compared to the results obtained from injections of tracer in the ventrolateral periaqueductal gray. Furthermore, the numbers of Fos-positive hypothalamic neurons that projected to the dorsolateral/lateral periaqueductal gray were very similar in experimental and control animals. The electrophysiological study confirmed that a large proportion of neurons in and around the lateral area of the anterior hypothalamus can be driven by noxious visceral stimulation and demonstrated a high incidence of viscerosomatic convergence in these cells (66% of cells driven from somatic structures were also driven by electrical stimulation of the splanchnic nerve). Somatic receptive fields of these neurons were generally large, often including all four limbs and the face. The results of the functional anatomical and electrophysiological studies have identified neurons in an area of the ventral anterior hypothalamus that are a focus of nociceptive visceral input and which project to the midbrain periaqueductal gray, in particular to its ventrolateral column. These results are discussed in relation to the roles of the anterior hypothalamus and the different longitudinal columns of the periaqueductal gray in co-ordinating autonomic and sensory functions in response to visceral pain.

Animals↗

A prospective clinical evaluation of autogenous vein grafts used as a nerve conduit for distal sensory nerve defects of 3 cm or less.

The purpose of this study was to determine the efficacy of autogenous vein grafts as nerve grafts (AVNC) for bridging of small peripheral sensory nerve gaps as compared with direct repair and with conventional nerve grafting techniques (ANG). Patients with painful neuroma or segmental nerve injury of 3 cm were chosen as the test group. Those amenable to direct repair were classified as controls. Between 1982 to 1988, a total of 22 patients were enrolled in this study. A total of 34 nerves were repaired, 15 with a venous nerve conduit, 4 with a sural nerve graft, and 15 with direct repair. Significant symptom relief and satisfactory sensory function return were uniformly observed. The two-point discrimination measurements indicated superiority of direct repair and probably of conventional nerve grafting. However, the universally favorable patient acceptance and the return of measurable two-point discrimination indicates the effectiveness of autogenous vein grafts as nerve conduits when selectively applied to bridge a small nerve gap (less than or equal to 3 cm) on nonessential peripheral sensory nerves.

Adult↗

Differential expression of Otx2, Gbx2, Pax2, and Fgf8 in the developing vestibular and auditory sensory organs.

The vertebrate inner ear is a complex organ with vestibular and auditory sensory functions, which derives from a single ectoderm structure, the otic placode. The development and regional patterning of the otic primordium is determined by the restricted expression of several genes. Here, we show the expression pattern of three transcription factors (Otx2, Gbx2, Pax2) and of a member of the fibroblast growth factor family (Fgf8) in the developing chick inner ear, and we correlate these patterns with the developing sensory and nonsensory elements.

Animals↗

Intensive early physiotherapy combined with dexamphetamine treatment in severe stroke: a randomized, controlled pilot study.

BACKGROUND: The most severely disabled stroke patients are often excluded from studies evaluating effects of physiotherapy. This study intended to investigate the effect of an increased intensity of physiotherapy in combination with dexamphetamine the first week after ischemic stroke in patients with an impaired level of consciousness and severe motor dysfunction. METHODS: Thirty patients were enrolled within 96 h after onset of symptoms. Patients were randomized to 30-45 min of physiotherapy twice daily or to maximally 15 min per day for 5 days. All patients received dexamphetamine to achieve alertness. Functional outcome measures were assessed at baseline, the day after treatment discontinuation, and 3 and 12 months after stroke onset. Residence of living was registered at long-term follow-ups. RESULTS: No statistically significant differences were seen between groups in the outcomes measured at any time point. However, both groups improved over time in all outcomes at 3 and 12 months (p < 0.05), except for sensory functions at 3 months and motor functions at 12 months. The number of patients needed to treat (NNT) to achieve the desired improvement in Lindmark motor score was 8, with the 95% CI being NNT(harm) 10 to NNT(beneficial) 3. The fraction of patients who died was the same in both treatment groups, 47% (95% CI 28-65%). CONCLUSIONS: An increased intensity of physiotherapy in combination with dexamphetamine during the first week after stroke onset did not affect short- or long-term outcome in this limited sample of patients with severe stroke.

Aged↗

Clinical neurological findings among car painters exposed to a mixture of organic solvents.

A full clinical neurological examination was used to study the possible effects of long-term exposure to low concentrations of mixtures of organic solvents on the nervous system. The exposed group consisted of 102 male car painters and the referents of 102 age- and sex-matched locomotive engineers and assistants. The psychoorganic syndrome, a decrease in the sense of light touch and pain, and an increase in the vibration threshold were more frequent among the car painters than among the referents, and the observed differences of these frequencies were statistically significant. The sense of vibration had been affected in the lower extremities of 65 of the 102 car painters and in 25 of the referents. Sensory functions seem to be the most vulnerable part of the nervous system of workers chronically exposed to different organic solvents.

Adult↗

Coupling between fibres involved in sensory nerve neuromata in cats.

Electrophysiological evidence has been obtained for coupling between pairs of fibres involved in 2 types of neuroma of a cutaneous sensory nerve in cats. A pair of fibres was taken to be coupled when an antidromic impulse in 1 fibre evoked an orthodromic impulse in the other. The fibres involved tended to be small diameter myelinated fibres and unmyelinated fibres. The coupling between a pair of fibres was stable over periods of several hours. Some of the coupled fibres had regenerated back to the skin and formed a functional sensory ending. These coupled responses can be explained by there being ephaptic interaction between fibres within the neuroma or they may be due to activity in retrograde sprouts of regenerating nerve fibres. Ephaptic interactions between fibres in a neuroma may be part of the explanation for abnormal sensibility, particularly pain sensibility, after peripheral nerve injury.

Animals↗

Upper airway sensation in snoring and obstructive sleep apnea.

Previous studies indicate that upper airway (UA) sensory receptors play a role in the maintenance of UA patency and contribute to arousal in response to airway occlusion. An impairment of UA sensory function could therefore predispose to UA obstruction during sleep. We hypothesized that UA sensation is impaired in obstructive sleep apnea (OSA), and that sensation improves after treatment with nasal continuous positive airway pressure (CPAP). We measured two-point discrimination (2PD) and vibratory sensation thresholds (VT) in 37 patients with OSA (mean [+/- SE] apnea- hypopnea index [AHI] = 39 +/- 5 events/h), 12 nonapneic snorers (SN), and 15 control subjects (CL). Sensory thresholds were determined in the UA and on the lip and hand as control sites. Both 2PD and VT were similar among the three groups at the lip and hand sites but were significantly reduced in the UA of OSA and SN subjects versus CL (p < 0.05). Values for 2PD and VT in the UA of OSA versus SN were not significantly different. Sensory measures were repeated after 6 mo in 23 OSA patients treated with CPAP as well as in 18 untreated patients. Thresholds for 2PD and VT at control sites remained identical in both groups, as did 2PD for the UA. However, VT in the UA showed a significant improvement in treated (4.4 +/- 0.2 pre-CPAP versus 3.8 +/- 0.2 mm post-CPAP, p < 0.05) but not untreated patients. These findings indicate the presence of a selective impairment in the detection of mechanical stimuli in the UA of patients with OSA and SN, which is partially reversible after treatment with nasal CPAP in patients with OSA.

Adult↗

Diabetic peripheral neuropathy: a correlation of nerve conduction studies and clinical findings.

The electrophysiologic and clinical characteristics of diabetes were studied in 56 patients having diabetes of adult onset. Historical data including age, duration of diabetes, treatment type, family history and clinical symptoms were noted. Nerve conduction studies of the median, ulnar, peroneal, tibial and sural nerves were performed, and the H reflex was determined. Clinical sensory function of vibration, light touch, and two-point discrimination, muscle stretch reflexes in all four extremities and skin temperatures in the lower extremities were recorded. The data indicated a close correlation of clinical and electrophysiologic findings. The data supported the concept that diabetic peripheral neuropathy is progressive. It was concluded that diabetic peripheral neuropathy was present if two of the following three determinations were abnormal: median motor or sensory latency, ulnar sensory latency and sural latency.

Adult↗

A morphological and functional assessment of Mycobacterium leprae-induced nerve damage in a guinea-pig model of leprous neuritis.

Nerve damage, resembling that caused by Mycobacterium leprae in man, was created by the injection of cobalt-irradiated M. leprae organisms into the tibial nerve of guinea-pigs. Assessment of nerve damage was made by clinical, electrophysiological and morphometric means at intervals up to 13 weeks after injection. Quantitative immunohistochemical analysis of neuropeptide-containing fibres in the skin of the foot was also carried out. Significant nerve damage occurred 3 weeks after injection of M. leprae organisms. Motor and sensory functional loss peaked at 5 weeks after injection, and there was a significant decrease of peptide-immunoreactive nerves in all skin compartments. The nerve damage was self-limiting and functional recovery had occurred by 13 weeks. The model shows many of the features found in the nerve damage of treated leprosy patients.

Animals↗

Embryonic expression of Lim-1, the mouse homolog of Xenopus Xlim-1, suggests a role in lateral mesoderm differentiation and neurogenesis.

cDNAs encoded by the mouse homolog (Lim-1) of the Xenopus LIM-class homeobox gene Xlim-1 have been isolated from an 8.5-day mouse embryo cDNA library. Nucleotide and deduced amino acid sequences show a high degree of identity with Xlim-1 in the LIM and homeodomains, and 85% identity over the whole protein. An interspecific back-cross has been used to show close linkage of Lim-1 to the endogenous proviral marker Mpmv-4 on mouse chromosome 11. Whole mount in situ hybridization studies have been carried out on mouse embryos between 6.5 and 10.5 days. In mid- to late-streak stage embryos, Lim-1 is expressed in a restricted region of mesoderm in the primitive streak, with the highest level of signal at the anterior. At 7.5 days, transcripts can be seen in a horseshoe-shaped pattern in the periphery of the node, as well as along both sides of the immediately adjacent notochord. In addition, transcripts are present in presumptive lateral and intermediate mesoderm. Later, expression becomes progressively restricted to intermediate mesoderm, the nephrogenic cords, and eventually mesonephric ducts and tubules. By 10.5 days Lim-1 transcripts also appear in restricted regions of the central nervous system (CNS) that are associated with sensory function. The lateral diencephalon, hindbrain, and presumed commissural neurons in the dorsal spinal cord all show Lim-1 expression. In the adult, Lim-1 is expressed in the cerebellum/medulla and kidney, and at very low levels in the cerebrum. These data suggest that in the mouse embryo Lim-1 plays a role in early mesoderm formation and later specification of a differentiated phenotype in subsets of cells of the mesonephros and sensory neurons of the CNS.

Amino Acid Sequence↗

Ultrastructural observations on the anterior adhesive apparatus in the monogeneans Dactylogyrus amphibothrium Wagener, 1857 and D. hemiamphibothrium Ergens, 1956.

The light microscope and the transmission electron microscope have revealed that the anterior adhesive apparatus of Dactylogyrus amphibothrium and that of D. hemiamphibothrium are similar and composed of three kinds of gland cell, one producing rod-shaped bodies (secretion S1), one producing spherical bodies (S2), and the third producing electronlucent vesicles (S3). In the cytoplasm of G1 gland cells each rod-shaped body is enclosed by a single layer of microtubules but no microtubules are associated with S2 and S3 bodies. The possible functions of these microtubules are discussed. The ducts which extend anteriorly from all three kinds of gland cell converge on and open into six adhesive sacs, situated ventrally on the distal extremities of the head lobes. Each adhesive sac is supplied with at least one gland duct from each type of gland cell and is lined by a special tegument bearing dense microvilli and a few cilia which may have a sensory function. It has been shown that during the attachment of the head region, these sacs are everted to expose the enclosed microvilli and duct openings and secretions S1 and S2 are extruded.

Animals↗

Human hand allograft: report on first 6 months.

BACKGROUND: Long-term survival of animal limb allografts with new immunosuppressant combinations and encouraging results of autologous limb replantations led us to believe that clinical application of hand transplantation in human beings was viable. METHODS: On Sept 23, 1998, we transplanted the right distal forearm and hand of a brain-dead man aged 41 years on to a man aged 48 years who had had traumatic amputation of the distal third of his right forearm. The donor's arm was irrigated with UW organ preservation solution at 4 degrees C, amputated 5 cm above the elbow, and transported in a cool container. We dissected the donor limb and the recipient's arm simultaneously to identify anatomical structures. Appropriate lengths of viable structures were matched. Transplantation involved bone fixation, arterial and venous anastomoses (ischaemic time 12.5 h), nerve sutures, joining of muscles and tendons, and skin closure. Immunosuppression included antithymocyte globulins, tacrolimus, mycophenolic acid, and prednisone. Maintenance therapy included tacrolimus, mycophenolic acid, and prednisone. Follow-up included routine post-transplant laboratory tests, skin biopsies, intensive physiotherapy, and psychological support. FINDINGS: The initial postoperative course was uneventful. No surgical complications were seen. Immunosuppression was well tolerated. Mild clinical and histological signs of cutaneous rejection were seen at weeks 8-9 after surgery. These signs disappeared after prednisone dose was increased (from 20 mg/day to 40 mg/day) and topical application of immunosuppressive creams (tacrolimus, clobetasol). Intensive physiotherapy led to satisfactory progress of motor function. Sensory progress (Tinel's sign) was excellent and reached the wrist crease (20 cm) on day 100 for the median and ulnar nerves, and at least 24 cm to the palm by 6 months when deep pressure, but not light touch sensation, could be felt at the mid palm. INTERPRETATION: Hand allotransplantation is technically feasible. Currently available immunosuppression seems to prevent acute rejection. If no further episode of rejection occurs, the functional prognosis of this graft should be similar to if not better than that reported in large series of autoreconstruction.

Adenosine↗

Comparison between the colonic J pouch-anal anastomosis and healthy rectum: clinical and physiological function.

BACKGROUND: Colonic pouch anastomosis after restorative rectal excision obviates much of the early dysfunction which is commonly experienced with the traditional straight coloanal anastomosis. A disadvantage with colonic pouch reconstruction, however, appears to be impaired evacuation. METHODS: Distal bowel function was investigated in 30 patients with a colonic J pouch anastomosis at 1 year after surgery and in 39 control subjects. RESULTS: While the degree of urgency and incontinence were similar, the patients with a pouch experienced more difficult evacuation. The maximum volume of the pouch (median 235 ml) and rectum (221 ml) was similar, but the rectum was more compliant (3.5 versus 2.6 ml per cmH2O, P < 0.01). The sensory function in terms of initial sensation of filling, urge to defaecate and maximum distension pressure was impaired in those with pouches. The amplitude of the neorectal and anal canal motility pattern was threefold that of controls. Maximum volume of the pouch was significantly associated with degree of impaired evacuation; the larger the volume the more difficult the evacuation. CONCLUSION: To reduce evacuation difficulty the pouch should not be fashioned too large. No conclusion about optimal pouch size could be drawn. In spite of fundamental physiological differences between a pouch and healthy anorectum, patients with a colonic pouch will usually experience satisfactory clinical bowel function.

Aged↗

Identification and analysis of Escherichia coli proteins that interact with the histidine kinase NtrB in a yeast two-hybrid system.

In this work we used the yeast two-hybrid (Y2H) system to deepen our understanding of protein-protein interactions that are involved in the nitrogen regulatory network in Escherichia coli. Three different genes, encoding GlnB, GlnK and AspA, respectively, were found among 64 positive clones identified from E. coli Sau3AI Y2H libraries using the nitrogen regulator NtrB as bait. Structural and functional analysis of the prey clones provided information on library features and the degree of saturation achieved in the screens. Further analysis revealed that the C-terminal kinase domain of NtrB is required for the interaction with GlnK, while AspA(91-312) interacts specifically with the conserved histidine phosphotransfer domain of NtrB, thus providing additional evidence for the involvement of the conserved transmitter module of the histidine kinase NtrB in input sensory functions.

Escherichia coli↗

Behavioral assessments of auditory sensitivity in transgenic mice.

This report summarizes positive reinforcement conditioning procedures for assessing sensory function in transgenic mice. To illustrate these behavioral methods auditory sensitivity was measured in mice lacking alpha9 acetylcholine receptor subunits (alpha9 knock-out mice). These receptors are known to play an important role in the efferent pathways that modify cochlear responses to sound stimuli. The strategies of parameter manipulation that led these subjects through their preliminary training stages to stable threshold performances are described in detail. Techniques for estimating and interpreting sensory thresholds are discussed from the perspective of signal detection analyses. This study found no significant differences between alpha9 knock-out mice and control subjects when hearing thresholds were measured under quiet conditions, as predicted by previous behavioral and electrophysiological evidence.

Acoustic Stimulation↗