Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033774 (pruritus)
 14,546 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The historical development of Swimmer's Itch is reviewed and details of investigative work done to discover the etiology and pathogenesis of the disease are presented. The distribution, life cycle, and necessary conditions for disease are discussed. A small epidemic of Swimmer's Itch in Lake Michigan is reported.
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PMID:Swimmer's itch. A review and case report. 57 Apr 71

Itch is a distinct sensation arising from the superficial layers of skin and mucous membranes. It is elicited by histamine and probably other endogenous chemicals that excite subpopulations of unmyelinated primary afferents and spinal neurones projecting through the anterolateral quadrant to the brain. The two popular views, which propose either that itch is signalled by a labelled line system of peripheral and central itch-specific neurones or that itch is the subliminal form of pain, both fail to explain convincingly many known features. Alternative theories emphasize central processes that extract the relevant information from afferents with broad sensitivity spectra for pruritogenic and noxious stimuli. Thus, itch presents an irritating challenge for the specificity theory of somatosensation.
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PMID:Itching for an explanation. 128 50

In order to investigate whether any regional difference in itch perception exists in experimentally induced pruritus, various concentrations of histamine (1, 3.3, 10, 33 and 100 micrograms/ml) were injected intradermally in three different skin regions in 15 healthy subjects. The regions were 1) the volar aspect of the forearm, 2) the lateral aspect of the upper arm and 3) the upper back at scapular level. Itch perception (itch latency, itch duration, maximal itch intensity, 'total itch index') and flare reactions were studied. A significant dose-response relationship was shown in each of the three regions for all itch variables, except itch latency, and for the flare reactions. However, no significant regional difference in itch perception was observed. The flare reaction showed a regional variation, with significantly smaller flares on the forearm than in the other two regions.
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PMID:Perception of histamine-induced itch elicited in three different skin regions. 167 21

Itch and flare responses were investigated in 32 patients with atopic dermatitis (AD) and in 32 healthy controls. Itch was induced chemically by intradermal injections of histamine (1, 3.3, 10 and 100 micrograms/ml) and compound 48/80 (10 micrograms/ml) into non-lesional skin and mechanically by wearing a woollen sweater. Continuous recording of itch intensity allowed the calculation of itch duration (ID), maximal itch intensity (Imax) and a "total itch index" (Tii). The itch responses were significantly increased in AD patients compared with controls for wool fibres and one of the histamine concentrations (10 micrograms/ml), but not for the remaining three histamine concentrations or compound 48/80. Conversely, the flare response was significantly smaller in AD patients than in controls for the two strongest histamine solutions and compound 48/80. Significant dose-response relationships were found between histamine concentration and each of ID, Imax, Tii and flare in both patients and controls. The slope of the flare-regression line was significantly steeper in controls than in AD patients, whereas the slopes of the itch-regression lines did not differ significantly between the two groups, i.e. their ability to discriminate between weak and strong histamine concentrations did not differ significantly. No increased skin mast cell releasability in vivo to compound 48/80 was shown in AD patients compared with controls. The itch and flare responses of AD patients did not correlate significantly with clinical itch intensity, eczema score or serum IgE level.
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PMID:Patients' perception of itch induced by histamine, compound 48/80 and wool fibres in atopic dermatitis. 172 58

The spectral envelope is a major determinant of the perceptual identity of many classes of sound including speech. When sounds are transmitted from the source to the listener, the spectral envelope is invariably and diversely distorted, by factors such as room reverberation. Perceptual compensation for spectral-envelope distortion was investigated here. Carrier sounds were distorted by spectral envelope difference filters whose frequency response is the spectral envelope of one vowel minus the spectral envelope of another. The filter /I/ minus /e/ and its inverse were used. Subjects identified a test sound that followed the carrier. The test sound was drawn from an /Itch/ to /etch/ continuum. Perceptual compensation produces a phoneme boundary difference between /I/ minus /e/ and its inverse. Carriers were the phrase "the next word is" spoken by the same (male) speaker as the test sounds, signal-correlated noise derived from this phrase, the same phrase spoken by a female speaker, male and female versions played backwards, and a repeated end-point vowel. The carrier and test were presented to the same ear, to different ears, and from different apparent directions (by varying interaural time delay). The results show that compensation is unlike peripheral phenomena, such as adaptation, and unlike phonetic perceptual phenomena. The evidence favors a central, auditory mechanism.
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PMID:Central, auditory mechanisms of perceptual compensation for spectral-envelope distortion. 178 36

A quantitative comparison was made of the effect of infiltration of local analgesics and topical analgesic cream (EMLA) on laser-induced pain and histamine-induced wheal, flare and itch. Wheal and flare were quantified by planimetry and analgesia was quantified by the pricking pain threshold to argon laser stimulation. The intensity of histamine-induced itch was scored on a 4-point scale. Local analgesics had no effect on the wheal area. The flare reaction was abolished by infiltrating lignocaine, and gradually inhibited by increased application times of EMLA. Itch was abolished after local lignocaine infiltration, but not significantly reduced after EMLA cream applied for less than 120 min, although the skin was anaesthetized to laser-induced pain. The reduction of flare area correlated to the level of analgesia, which may therefore reflect the cutaneous responsiveness to neurogenic inflammation. It is suggested that itch and pricking pain are mediated by different populations of nerve fibres, as itch can be evoked even when the sensation of pricking pain is abolished. Surgery, skin prick tests and other traumatic procedures should therefore be performed under local anaesthesia to reduce neurogenic inflammation.
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PMID:A quantitative comparison of the effect of local analgesics on argon laser induced cutaneous pain and on histamine induced wheal, flare and itch. 196 96

An investigation was carried out to determine whether tactile sensibility was affected by anterolateral cordotomy. There were 65 patients who had cordotomies for painful forms of cancer. Thirty eight had necropsy examination with histological investigation of the spinal cord. No form of mechanoreception was removed in any of the 65 patients and in the majority no forms of tactile sensibility were altered by division of the pathways in the anterolateral and anterior columns. In no case was graphaesthesia affected. Knowledge of joint position and movement and awareness of vibration was normal in 62 of the 65 patients. But information carried by these anterolateral pathways does reach neural levels of consciousness, for with total lesions of the posterior columns, previously reported, touch and pressure are still felt. Itch was removed by division of the anterolateral pathways. Although the posterior columns are essential for discrimination in mechanoreception, discrimination may be disturbed by lesions of the anterolateral pathways, notably two-point discrimination. The evidence on the pathways essential for conveying impulses giving rise to tickle was inconclusive.
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PMID:Touch and surgical division of the anterior quadrant of the spinal cord. 228 23

Itch was assessed both continuously using a computerized method, Pain-Track, and retrospectively using visual analogue scales (VAS) by 28 patients undergoing maintenance hemodialysis and suffering from uremic pruritus. Measurements were performed during 7 consecutive days including three dialysis sessions. Pain-Track recordings showed that itch intensity was greater during dialysis than on days following dialysis (p less than 0.05). Possible explanations are that pruritogenic substances might be released during treatment or that removal of such substances during dialysis leads to amelioration of symptoms after treatment. Alternatively, lowering of the sensory threshold due to general discomfort in association with dialysis may exacerbate the itch intensity. There was no consistent difference between daytime and bedtime itch scores over the week, except on the second day without treatment, when bedtime itch ratings significantly exceeded those during the day (p less than 0.05), suggesting that factors other than inactivity are essential for this peak in itch intensity. Thus, after 2 days without treatment, when patients become increasingly metabolically deranged, they reported maximal itch, implying that the accumulation of pruritogenic substances is of major importance in the pathogenesis of uremic pruritus. There was a positive correlation between Pain-Track and VAS data, although significant fluctuations in itching could be detected only with Pain-Track.
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PMID:Computerized recording of itch in patients on maintenance hemodialysis. 257 7

Itch sensations and skin reactions induced by histamine iontophoresis at six different current intensities were studied in 27 atopic dermatitis (AD) patients and 20 healthy controls. Subjective itch ratings were assessed on a visual analogue scale (VAS) for 8-min periods after 10-sec histamine application, while changes of skin blood flow were simultaneously measured using two Laser Doppler flowmeters. Ten minutes after each histamine application, the areas of wheal and flare reactions were planimetrically evaluated. When no or weak current was applied, AD patients revealed stronger wheal and flare reactions than controls, possibly due to disturbed skin barrier function. Higher histamine doses, however, produced weaker subjective and vascular reactions in AD patients. In contrast to the controls, AD patients were unable to distinguish between weak and strong histamine stimulation, as shown by their VAS ratings. These results imply that AD patients have an altered histamine response. In particular, their afferent cutaneous nerve fibers show a decreased ability to signal itching to the central nervous system and to release vasoactive neuropeptides upon histamine stimulation.
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PMID:Skin reactions and itch sensation induced by epicutaneous histamine application in atopic dermatitis and controls. 267 98

In hyperparathyroidism associated with endstage renal failure, either subtotal, or total parathyroidectomy with autotransplantation have been advocated as potentially curative for those patients non-responsive to medical therapy. Seventeen such patients managed by the Wellington renal unit were reviewed as to indications for, and responses to, surgery. Itch, psychiatric symptoms, joint ache, muscular weakness, gritty eyes and thirst were the major symptoms for which surgery was recommended. Hypercalcaemia (universal in women) and deterioration in bone radiology were additional indications for operation. All showed remarkable postoperative improvement. Symptomatic hypocalcaemia was significant in 41%. This observation has led to intensified pre- and postoperative vitamin D and calcium therapy. Postoperative radiologic improvement at three months was apparent in 80% of patients. We advocate subtotal parathyroidectomy as the effective surgical treatment of choice for uraemic hyperparathyroidism.
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PMID:Parathyroid surgery in chronic renal failure. 386 72


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