Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0162473 (Frey)
 2,599 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mechanoreceptors in the periodontal ligament are activated by tooth movements as little as 1-3 microns. It has been difficult in the past to move a tooth only over this small distance in order to activate the periodontal receptors without at the same time activating other receptors in related structures. This paper describes a simple solution to this problem based on the use of von Frey hairs (in the form of nylon filaments) rather than a rigid probe, to move the tooth. Filaments of different stiffness are mounted on the moving coil of a loudspeaker to apply different forces to the tooth. The timing of the contact of the filament with the tooth is measured precisely with a simple impact detector. The sensation elicited by this stimulator is abolished by local alveolar anaesthesia, indicating that the stimulation was localised to the periodontal area. The flexible probe is an important safety feature, as it limits the force applied to the tooth, and therefore the distance that the tooth can be displaced. The stimulator, suitable for psychophysical studies on the thresholds of periodontal receptors, on the reflex responses to stimulation of periodontal mechanoreceptors, and teaching applications, can be constructed from readily available components at minimal cost.
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PMID:A simple stimulator for periodontal mechanoreceptors in human subjects. 130 86

In ischemic and in inflamed tissues, pH levels down to 5.4 have been measured, and this local acidosis may contribute to pain and hyperalgesia in disease states. To evaluate the role of acid pH in nociception, we have studied identified primary afferents in a rat skin-saphenous nerve preparation in vitro where the receptive fields can be superfused at the highly permeable corium side with controlled solutions. The nerve endings were exposed to CO2-saturated synthetic interstitial fluid (SIF;pH 6.1) and to carbogen-gassed SIF phosphate buffered to different acid pH levels (5 min duration, 10 min intervals). Mechanical thresholds were repeatedly tested in a "blind" fashion by von Frey hair stimulation. Low-threshold mechanosensitive A beta- (n = 12) and A delta-fibers (n = 11) were not excited or sensitized by acid pH levels. In 24 of 96 nociceptor type C- and A delta-fibers, irregular low-frequency discharge with poor response characteristics was induced. However, a distinct subpopulation of mechanoheat sensitive, "polymodal" C-units (n = 25; 38%) showed stimulus-related responses increasing with proton concentration and encoding the time course of the pH change. Threshold levels were found to range from pH 6.9 to 6.1; mean maximum discharge was at pH 5.2. All such fibers responded to CO2 as well as to phosphate-buffered solution at the same pH 6.1. The CO2 responses, however, displayed significantly shorter latencies and more pronounced dynamic phases. The carboanhydrase blocker acetazolamide markedly delayed and reduced the CO2 responses. Prolonged application of acid pH (30 min) evoked nonadapting activity irrespective of oxygen supply. Many, but certainly not all, fibers sensitive to protons were also driven by capsaicin (10(-6) M, 10(-5) M) and vice versa. Repeated or prolonged treatment with low pH induced a significant and lasting decrease of the mechanical (von Frey) thresholds in almost all C-fibers tested (from 35 to 16 mN, on average), and this occurred whether or not a fiber was excited by protons. The sensitizing effect was more pronounced the higher the initial von Frey thresholds (0.75 rank correlation). This sensitization to mechanical stimulation was in contrast to the combined action of other inflammatory mediators, bradykinin, 5-HT, histamine and prostaglandin E2. In conclusion, we suggest that pH sensitivity of nociceptors may be an important source of pain and hyperalgesia.
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PMID:Protons selectively induce lasting excitation and sensitization to mechanical stimulation of nociceptors in rat skin, in vitro. 130 78

A study was made of 187 patients with parotid pleomorphic adenoma treated by radiotherapy. This followed surgery but with incomplete removal or tumor spillage. In the early years of the study radiotherapy was given by radium needle implant done usually at the time of surgery, but from the late 1960s beam-directed external radiotherapy with a head shell was used most commonly. A 3-field technique or wedge pair was the standard technique. The median age was 46 with nearly half the patients (87/187) aged between 40 and 60, and the ratio of women to men was 1.4:1 (110:77). Median follow-up for all patients was 14 years. One hundred fifteen patients had radiotherapy immediately after their first operation with a recurrence rate of 0.9% (1/115). Of the 115 there were 2 cases of radionecrosis (1 major, 1 minor), 1 case of permanent facial nerve palsy, 1 Frey Syndrome (post-gustatory sweating), and 1 salivary fistula. Seventy-two patients had radiotherapy delayed until one or more recurrences had been surgically treated. Nine (12.5%) of these developed yet further recurrence after radiotherapy. There were 2 cases of radionecrosis (1 major), 4 cases of facial nerve palsy (3 of which were complete), 16 cases (22.2%) of Frey Syndrome, and 1 case of malignant change in a parotid tumor. In addition one squamous cell carcinoma developed at the site of a needle implant 25 years later. Recurrences after radiotherapy continued beyond 20 years of follow-up. Patients having unsatisfactory surgery due to spill at operation or residual tumor left behind should have radiotherapy immediately and not delayed until local recurrence occurs because of the increased morbidity and the higher incidence of yet further recurrence.
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PMID:Radiotherapy for pleomorphic adenoma of the parotid gland. 155 68

The endogenous peptide bradykinin is found in plasma and inflammatory exudates and has been implicated as a chemical mediator of inflammatory pain and hyperalgesia. Two subtypes of bradykinin receptors, B1 and B2, have been described, and antagonists for the receptor subtypes have been synthesized. The bradykinin analogs [desArg9,Leu8]BK and DArg[Hyp3,DPhe7]BK have been reported to have antagonist activity at the B1 and B2 bradykinin receptors in smooth muscle, respectively. Behavioral studies in rats indicate that the bradykinin analogs can block the algesic effects of bradykinin. We wished to determine the effects of bradykinin and the bradykinin analogs (B1 and B2 analogs, respectively) on cutaneous nociceptors in the monkey. In addition, we wished to determine the type of bradykinin receptor that mediates the sensitizing effects of bradykinin. Recordings were made from single C-fiber and A-fiber nociceptive afferents (CMHs and AMHs) that innervated hairy skin. Heat sensitivity before and after the injections was determined with a heat test sequence consisting of stimuli that ranged, in 1 degree C increments, from 41 degrees to 49 degrees C. Intradermal injections of vehicle (neutral normal saline) failed to alter the heat response of CMHs. Bradykinin (10 nmol in 10 microliters) evoked activity in 6 of 10 CMHs and sensitized all the fibers to heat stimuli. After the bradykinin injection, the mean heat threshold of the CMHs decreased from 44 +/- 0.5 degrees to 42.7 +/- 0.5 degrees C (mean +/- SEM, p less than 0.02), and the total response to the heat test sequence increased by 87% (p less than 0.002). In a related psychophysical study in human volunteers, the same dose of bradykinin resulted in a comparable (115%) increase in ratings of pain (Manning et al., 1991). Bradykinin also evoked activity in 10 of 17 AMHs and sensitized 8 AMHs to heat stimuli. Bradykinin failed to alter the threshold for activation of CMHs to mechanical stimuli as measured by application of von Frey hairs to the receptive field. In contrast to bradykinin, intradermal injection of the B1 and B2 analogs (10 nmol in 10 microliters) evoked activity in 2 of 6 and 0 of 5 CMHs, respectively. A noteworthy finding was that both analogs enhanced the response of CMHs to heat stimuli by 50% (B1 analog, 1.5 +/- 0.1; B2 analog, 1.5 +/- 0.2). The B1 (n = 10) and B2 (n = 5) analogs did not evoke activity in any of the 15 AMHs tested.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The effects of bradykinin and sequence-related analogs on the response properties of cutaneous nociceptors in monkeys. 132 2

Between 1980 and 1990, 35 patients underwent conservative parotidectomy combining a rhytidectomy incision and a superficial musculoaponeurotic system preservation technique to reduce the postoperative incidence of Frey's syndrome. All patients were evaluated by questionnaire for subjective symptoms of gustatory sweating and flushing as well as satisfaction with the aesthetic appearance of their cheek. Six percent of patients (2 of 35) complained of symptoms of Frey's syndrome. Ninety-four percent of patients (33 of 35) noticed minimal or no contour deformity of the surgical area. Twenty patients underwent Minor's starch iodine testing to identify objective evidence of aberrant nerve regeneration at the postoperative site. Fifteen percent of these patients (3 of 20) demonstrated a positive starch iodine test; however, one of these three patients was unaware of symptoms of Frey's syndrome. Symptoms of gustatory sweating are a reliable indicator of aberrant nerve regeneration. Conservative parotidectomy with superficial musculoaponeurotic system preservation for benign parotid disease produces a low incidence of Frey's syndrome and satisfactory cosmetic results.
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PMID:Frey's syndrome: prevention with conservative parotidectomy and superficial musculoaponeurotic system preservation. 132 50

Postoperative complications in 206 submandibular gland excisions, excluding those resulting from benign or malignant tumours, carried out during a 15-year period were reviewed. Most patients (62%) had sialolithiasis. Coexistence of sialolithiasis and nephrolithiasis was documented in 5.5% of cases. Early postoperative complications (particularly infection) developed in 14.6% of the cases, whereas late complications appeared in 25.3% of the cases (residual inflammation in Wharton's duct 7.3%). Neurological complications were observed in 16% of the cases. In 7 cases (3.4%) several nerves were involved and almost always the hypoglossal nerve. In 37.4% of the cases, these lesions resolved spontaneously in a mean period of 4 months. In those cases with a permanent neurological deficit, the facial nerve was the most often affected (7.7%) followed by the hypoglossal (2.9%) and the lingual nerve (1.4%). A single case of gustatory sweating (Frey's) syndrome was observed.
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PMID:Morbidity associated with removal of the submandibular gland. 132 5

A total of 46 patients with benign parotid gland tumours have been operated upon between 1979 and 1989 in the Department of Otolaryngology at Leicester Royal Infirmary. Thirty-one were pleomorphic adenomas, six Warthin's tumours and nine miscellaneous tumours or tumour-like lesions. Extracapsular lumpectomy without facial nerve preparation was used in 31 cases (67%) and superficial parotidectomy in 15 cases (33%). One case of permanent partial facial palsy and one recurrence occurred in patients who underwent superficial parotidectomy. Frey's syndrome occurred in 40% of patients undergoing superficial parotidectomy. No permanent palsy, recurrence or Frey's syndrome occurred after extracapsular lumpectomy. These results suggest that extracapsular lumpectomy may reduce the morbidity rate in carefully selected patients.
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PMID:Complications of superficial parotidectomy versus extracapsular lumpectomy in the treatment of benign parotid lesions. 132 26

Lysine 2,3-aminomutase from Clostridia catalyzes the interconversion of L-alpha-lysine with L-beta-lysine. The purified enzyme contains iron-sulfur ([Fe-S]) clusters, pyridoxal phosphate, and Co(II) [Petrovich, R. M., Ruzicka, F. J., Reed, G. H., & Frey, P. A. (1991) J. Biol. Chem. 266, 7656-7660]. Enzymatic activity depends upon the presence and integrity of these cofactors. In addition, the enzyme is activated by S-adenosylmethionine, which participates in the transfer of a substrate hydrogen atom between carbon-3 of lysine and carbon-2 of beta-lysine [Moss, M., & Frey, P. A. (1987) J. Biol. Chem. 262, 14859-14862]. This paper describes the electron paramagnetic resonance (EPR) properties of the [Fe-S] clusters. Purified samples of the enzyme also contain low and variable levels of a stable radical. The radical spectrum is centered at g = 2.006 and is subject to inhomogeneous broadening at 10 K, with a p1/2 value of 550 +/- 100 microW. The low-temperature EPR spectrum of the [Fe-S] cluster is centered at g = 2.007 and undergoes power saturation at 10 K in a homogeneous manner, with a p1/2 of 15 +/- 2 mW. The signals are consistent with the formulation [4Fe-4S] and are adequately simulated by a rhombic spectrum, in which gxx = 2.027, gyy = 2.007, and gzz = 1.99. Treatment of the enzyme with reducing agents converts the cluster into an EPR-silent form. Oxidation of the purified enzyme by air or ferricyanide converts the [Fe-S] complex into a species with an EPR spectrum that is consistent with the formulation [3Fe-4S].(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of iron-sulfur clusters in lysine 2,3-aminomutase by electron paramagnetic resonance spectroscopy. 132 54

Electron paramagnetic resonance (EPR) spectroscopy has been used to characterize an organic radical that appears in the steady state of the reaction catalyzed by lysine 2,3-aminomutase from Clostridium SB4. Results of a previous electron paramagnetic resonance (EPR) study [Ballinger, M. D., Reed, G. H., & Frey, P. A. (1992) Biochemistry 31, 949-953] demonstrated the presence of EPR signals from an organic radical in reaction mixtures of the enzyme. The materialization of these signals depended upon the presence of the enzyme, all of its cofactors, and the substrate, lysine. Changes in the EPR spectrum in response to deuteration in the substrate implicated the carbon skeleton of lysine as host for the radical center. This radical has been further characterized by EPR measurements on samples with isotopically substituted forms of lysine and by analysis of the hyperfine splittings in resolution-enhanced spectra by computer simulations. Changes in the hyperfine splitting patterns in EPR spectra from samples with [2-2H]lysine and [2-13C]-lysine show that the paramagnetic species is a pi-radical with the unpaired spin localized primarily in a p orbital on C2 of beta-lysine. In the EPR spectrum of this radical, the alpha-proton, the beta-nitrogen, and the beta-proton are responsible for the hyperfine structure. Analysis of spectra for reactions initiated with L-lysine, [3,3,4,4,5,5,6,6-2H8]lysine, [2-2H]lysine, perdeuteriolysine, [alpha-15N]lysine, and [alpha-15N,2-2H]lysine permit a self-consistent assignment of hyperfine splittings.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Structure of a substrate radical intermediate in the reaction of lysine 2,3-aminomutase. 132 55

We attempted to develop an experimental animal model for peripheral neuropathic pain. Under sodium pentobarbital anesthesia, both the L5 and L6 spinal nerves (group 1) or the L5 spinal nerve alone (group 2) of one side of the rat were tightly ligated. For comparison, a parallel study was conducted with another group of rats (group 3) which received a partial tight sciatic nerve ligation, a paradigm developed previously as a neuropathy model. Withdrawal latencies to application of radiant heat to the foot were tested for the next 16 weeks in all 3 groups. Sensitivity of the hind paw to mechanical stimulation was tested with von Frey filaments. The general behavior of each rat was noted during the entire test period. Results suggested that the surgical procedure in all 3 groups produced a long-lasting hyperalgesia to noxious heat (at least 5 weeks) and mechanical allodynia (at least 10 weeks) of the affected foot. In addition, there were behavioral signs of the presence of spontaneous pain in the affected foot. Therefore, we believe we have developed an experimental animal model for peripheral neuropathy using tight ligations of spinal nerves. The model manifests the symptoms of human patients with causalgia and is compatible with a previously developed neuropathy model. The present model has two unique features. First, the surgical procedure is stereotyped. Second, the levels of injured and intact spinal segments are completely separated, allowing independent experimental manipulations of the injured and intact spinal segments in future experiments to answer questions regarding mechanisms underlying causalgia.
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PMID:An experimental model for peripheral neuropathy produced by segmental spinal nerve ligation in the rat. 133 81


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