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pH Probe (ph + probe)

Distribution by Scientific Domains

Medical Sciences	62%
Chemistry	37%

Selected Abstracts

Correlation of pH Probe,Measured Laryngopharyngeal Reflux With Symptoms and Signs of Reflux Laryngitis,

THE LARYNGOSCOPE, Issue 12 2002
J. Pieter Noordzij MD
Abstract Objectives/Hypothesis Laryngitis secondary to gastric acid reflux is a prevalent, yet incompletely understood, otolaryngological disorder. Further characterization of the relationship between symptoms and signs and reflux severity is needed. Study Design Prospective clinical trial. Methods Forty-two consecutive, nonsmoking patients with one or more reflux laryngitis symptoms were recruited to complete a symptom questionnaire, videostrobolaryngoscopy, and 24-hour, dual-sensor pH probe testing. Twenty-nine patients had more than four episodes of laryngopharyngeal reflux, and the remaining 13 served as control subjects. Symptom scores were produced by multiplying the severity by the frequency for the following: hoarseness, throat pain, "lump-in-throat" sensation, throat clearing, cough, excessive phlegm, dysphagia, odynophagia, and heartburn. Endoscopic laryngeal signs included erythema and edema of the vocal folds and arytenoids, and interarytenoid irregularity. Results Symptom scores varied significantly, with throat clearing being greater than the rest. None of the symptoms, except heartburn, correlated with reflux (laryngopharyngeal and esophageal) severity. Patients with worse laryngopharyngeal reflux were found to have worse esophageal reflux. Endoscopic laryngeal signs were rated as mild, on average, and did not correlate with laryngopharyngeal reflux severity. The number of laryngopharyngeal reflux episodes (per 24 h) ranged from 0 to 40 (mean number, 10.6 episodes). Conclusions Throat clearing was the most intense symptom in the present group of patients with proven reflux laryngitis. Dual-sensor pH probe testing could not predict the severity of patient's reflux laryngitis symptoms or signs. Only the heartburn symptom correlated with laryngopharyngeal and esophageal reflux. [source]

Photophysics of a Series of Efficient Fluorescent pH Probes for Dual-Emission-Wavelength Measurements in Aqueous Solutions

CHEMISTRY - A EUROPEAN JOURNAL, Issue 4 2006
Sandrine Charier Dr.
Abstract This paper evaluates the 5-aryl-2-pyridyloxazole backbone to engineer donor,acceptor fluorescent pH probes after one- or two-photon absorption. Parent fluorophores, as well as derivatives that can be used to label biomolecules, can be easily obtained in good yields. These molecules exhibit a large one-photon absorption in the near-UV range, and a strong fluorescence emission that covers the whole visible domain. The 5-aryl-2-pyridyloxazole derivatives also possess significant cross sections for two-photon absorption. Upon pyridine protonation, large shifts were observed in the absorption spectra after one- and two-photon excitation, as well as in the emission spectra. This feature was used to measure the pKa of the investigated compounds that range between 2 and 8. In most of the investigated derivatives, the pKa increased upon light excitation and protonation exchanges took place during the lifetime of the excited state, as shown by phase-modulation fluorometry analysis. Several 5-aryl-2-pyridyloxazole derivatives are suggested as efficient probes to reliably measure the pH of aqueous solutions by means of ratiometric methods that are dependent on fluorescence emission. Cet article évalue le squelette 5-aryl-2-pyridyloxazole pour la conception de sondes fluorescentes de pH de type donneur,accepteur après excitation à un ou deux photons. Il est facile d'obtenir avec de bons rendements et en grande quantité les têtes de série tout autant que des dérivés conçus pour effectuer la fonctionnalisation de biomolécules. Ces sondes absorbent intensément la lumière dans le proche UV et présentent une forte émission de fluorescence qui couvre toute l'étendue du domaine visible. Elles possèdent aussi d'appréciables sections efficaces d'absorption à deux photons. La protonation du cycle pyridine s'accompagne de déplacements importants à la fois dans les spectres d'absorption après excitation à un et deux photons, et dans les spectres d'émission. Ces altérations sont utilisées pour mesurer le pKades sondes synthétisées qui s'étage entre 2 et 8. Une étude par fluorimétrie de phase démontre que le pKade la plupart de ces sondes augmente après absorption lumineuse et que des réactions acido,basiques se produisent au cours de la durée de vie de l'état excité. Ce manuscrit démontre que plusieurs 5-aryl-2-pyridyloxazoles constituent des sondes de pH efficaces et fiables pour mesurer le pH en solution aqueuse par analyse ratiométrique en émission. [source]

Effect of paddock vs. stall housing on 24 hour gastric pH within the proximal and ventral equine stomach

EQUINE VETERINARY JOURNAL, Issue 4 2008
L. HUSTED
Summary Reasons for performing study: Stall housing has been suggested as a risk factor for ulcer development in the equine stomach; however, the exact pathogenesis for this has not been established. Objectives: To investigate the effect of 3 environmental situations (grass paddock, stall alone or stall with adjacent companion) on pH in the proximal and the ventral stomach. Methods: Six horses with permanently implanted gastric cannulae were used in a randomised, cross-over, block design. Each horse rotated through each of three 24 h environmental situations. Horses remained on their normal diet (grass hay ad libitum and grain b.i.d.) throughout the study. Intragastric pH was measured continuously for 72 h just inside the lower oesophageal sphincter (proximal stomach) and via a pH probe in the gastric cannula (ventral stomach). Results: Neither proximal nor ventral 24 h gastric pH changed significantly between the 3 environmental situations. Mean hourly proximal gastric pH decreased significantly in the interval from 01.00,09.00 h compared to the interval from 13.00,20.00 h, regardless of environmental situation. Median hourly proximal pH only differed in the interval from 06.00,07.00 h compared to the interval 14.00,19.00 h. Neither mean nor median hourly ventral gastric pH varied significantly with the time of day. Conclusions: The change in housing status used in the current study did not affect acid exposure within either region of the equine stomach. The pH in the ventral stomach was uniformly stable throughout the study, while the proximal pH demonstrated a 24 h circadian pattern. Potential relevance: Since stall housing was not associated with prolonged acid exposure to the proximal stomach, this aspect alone does not explain the increased risk of squamous ulcer development. The circadian rhythm associated with proximal intragastric pH warrants further investigation. [source]

Determination of the activity of H+ ions within and beyond the pH meter range

AICHE JOURNAL, Issue 12 2001
Eva Rodil
This work confirms that the activities of individual ions measured with ion-selective electrodes are physically meaningful. The individual activities of the Cl,, Na+ and K+ ions in single-electrolyte aqueous solutions of HCl, NaOH and KOH were measured at 298.2 K in the range from 0 to 2 molal. In the pH range from 1 to 13, the pH values calculated from the measured activities of the ions are in good agreement with the values obtained with a pH probe. In agreement with previous results for potassium ions, and opposite to the behavior of other cations in 1:1 electrolyte solutions, the K+ and the H+ ions were found to have smaller activities than their conjugate anions. The experimental activity coefficients of the ions were correlated with the Khoshkbarchi-Vera equation and with the New Hydration Theory, and compared with the predictions given by the Pitzer theory. [source]

Polysomnographic findings in 320 infants evaluated for apneic events

PEDIATRIC PULMONOLOGY, Issue 3 2006
Ignacio Sanchez MD
Abstract Apnea is a common problem that causes significant parental anxiety. The aim of this study was to describe polysomnographic findings in infants who were referred over a 4-year period for an apnea and/or cyanotic event. Our hypothesis was that most infants with apnea or cyanosis events will have normal polysomnography (PSG). In total, 320 patients younger than 2 years old were recruited sequentially and prospectively. Patients underwent a day or overnight PSG by computerized polysomnograph; 78% of studies were performed with pH probe in situ. Subjects' ages ranged from 10 days to 21 months (55% male and 84% full-term babies); 55% and 74% were younger than 3 and 6 months, respectively. The average total sleep time was 473.4 min (SD, 52.3), with mean sleep efficiency of 83.5%. The distribution of sleep stages was 56.5% active, 38.5%, quiet and 5.1% indeterminate sleep. Sixty-nine percent (n,=,220) of PSG studies were done overnight. There were significant differences in average sleep efficiency (78.1% vs. 83.3%) and REM sleep time (63.6% vs. 59.1%) between PSGs done during the day and overnight (P,<,0.05). In total, 34 patients with apneas were studied. The median apnea index for the whole study population was 1.01 (range, 0.1,9.1). In conclusion, our study showed a high prevalence of normal polysomnographic findings in infants referred because of apnea and/or cyanotic events. New clinical prospective studies should be conducted to evaluate whether there is a correlation between PSG findings and outcome at follow-up of infants with a history of apnea and cyanosis. Pediatr Pulmonol. © 2006 Wiley-Liss, Inc. [source]

Correlation of Findings on Direct Laryngoscopy and Bronchoscopy With Presence of Extraesophageal Reflux Disease

THE LARYNGOSCOPE, Issue 9 2000
Michele M. Carr DDS
Abstract Objective To determine the correlation between findings at direct laryngoscopy and bronchoscopy and presence of extraesophageal reflux disease (EERD). Study Design Retrospective chart review Methods Operative notes of 155 children undergoing direct laryngoscopy and bronchoscopy between 1996 and 1999 for airway symptoms for whom there was a suspicion of EERD were examined. Gastroesophageal reflux disease (GERD) was considered present if at least one test was positive (including upper GI series, pH probe, gastric scintiscan, or esophageal biopsy). Results A total of 130 (84%) patients had GERD diagnosed. Ninety percent had at least one laryngotracheal abnormality: 83% had an abnormal larynx and 66% had an abnormal trachea. Laryngeal abnormalities in GERD included postglottic edema, 69%; arytenoid edema, 30%; large lingual tonsil, 16%; vocal fold edema, 12%; vocal fold nodule, 12%; ventricular obliteration, 5%; and hypopharyngeal cobblestoning, 3%. Tracheobronchial abnormalities in GERD included tracheal cobblestoning, 33%; blunting of carina, 12.5%; subglottic stenosis, 11%; increased secretions, 11%; and generalized edema or erythema, 5%. The best sensitivity or specificity was obtained by combining postglottic edema, arytenoid edema, and vocal fold edema, resulting in a sensitivity of 75% and a specificity of 67%. Positive predictive value was 100% for the combination of postglottic edema and any vocal fold or ventricular abnormality. Conclusion Laryngoscopy and bronchoscopy can reveal findings with a high positive predictive value for the presence of GERD. Endoscopy of the upper airway in children with clinical signs and symptoms of EERD is a promising tool for diagnosis. [source]

Reflux as a cause of tracheoesophageal puncture failure

THE LARYNGOSCOPE, Issue 1 2009
Kavita M. Pattani MD
Abstract Objective: To evaluate the response to empiric reflux management in treatment of tracheoesophageal punctures (TEP) failures. Methods: A retrospective chart review of patients with failed TEP was performed (n = 37). Only those patients without any documented anatomic cause for failure (n = 22) were then further reviewed to determine if empiric treatment for reflux improved voicing. Evidence of reflux was determined by either using video flexible scope of the neopharynx, barium swallows, 24-hour pH probes, and /or transnasal esophagoscopy (TNE). In 13 of 22 patients who had voicing difficulties and no evidence of reflux on these tests, empiric treatment with antireflux medications had been documented. The 22 patients were closely monitored to determine the role of reflux therapy and subsequent voicing outcomes. Results: Of the 22 patients studied, 9 were noted to have granulation tissue on the tracheal side of the prosthesis. All nine patients had complete resolution of the granulation tissue after antireflux treatment, and seven of nine were able to voice again. Of the patients with no obvious reason for TEP failure who were empirically treated for reflux, 62% (8 of 13) had TEP voice after treatment. Seventy-seven percent of our patients (17 of 22) had a positive response to treatment with aggressive reflux therapy. Conclusions: Previous studies have demonstrated patients with a total laryngectomy and/or radiation therapy have increased reflux. This study addresses reflux as a potential cause of TEP voicing problems. We noted 41% (9 of 22) of patients with voicing difficulties had granulation tissue surrounding the prosthesis as a result of reflux. Aggressive antireflux therapy proved beneficial in eradicating this problem. Prophylactic antireflux therapy may be warranted for patients undergoing TEP to reduce voicing problems. Laryngoscope, 119:121,125, 2009 [source]