Biomedical subjects

A Dendorfer

Publications and source records attributed to A Dendorfer.

39 records · Page 3Linked to original sources

PubMed1987

Optimal thresholds, sensitivity, and specificity of long-term pH-metry for the detection of gastroesophageal reflux disease.

Long-term esophageal pH-metry has become the preferred test to quantify acid gastroesophageal reflux, but its accuracy in separating physiologic from pathological reflux is not well defined. To establish optimal thresholds of 24-h pH-metry, we studied 45 patients with clinically proven gastroesophageal reflux disease and 42 healthy volunteers. Twenty-four-hour esophageal pH was measured while the subject was ambulatory, using a combined glass electrode connected to a portable recorder. Percentage of time with esophageal pH less than 4, the number and mean duration of reflux episodes, the number of episodes lasting longer than 5 min, and the duration of the longest episode were calculated for periods of upright and supine body position, respectively. Discriminant analysis and receiver-operating-characteristic analysis were used to define optimal thresholds. A maximum of sensitivity (93.3%) and specificity (92.9%) was obtained using receiver-operating-characteristic analysis with the following criteria. Only percentage of time with esophageal pH less than 4 is considered. A subject is classified as "normal" if both values for the upright and supine body position are below the thresholds, otherwise the subject is classified as "pathological." The thresholds are 10.5% of time with esophageal pH less than 4 for the upright position and 6.0% for the supine position. Within the limits of this retrospective study, it is concluded that rather simple criteria yield a high diagnostic accuracy in the evaluation of long-term esophageal pH-metry. Nevertheless, a prospective and independent confirmation of these criteria is needed.

Adolescent↗

PubMed1987

Influence of smoking and esophageal intubation on esophageal pH-metry.

The effect of cigarette smoking on gastroesophageal reflux and the effect of the pH electrode on salivary secretion and swallowing frequency were studied in 30 healthy volunteers (15 habitual smokers, 15 non-smokers) and in 10 smoking patients with proven gastroesophageal reflux disease. Twenty-four-hour pH profiles were measured while the subjects were ambulatory using a combined glass electrode connected to a portable recorder. In 8 of the smoking volunteers, swallowing frequency and salivary secretion were measured, both when smoking and when not. Smokers had more reflux episodes than nonsmokers [median per hour 2.8 (range 0.4-7.1) for the upright body position and 0.5 (range 0.0-1.7) for the supine body position vs. 1.4 (range 0.0-2.1) upright and 0.0 (range 0.0-0.7) supine, p less than 0.01], but the total time of exposure of the esophageal mucosa to acid was affected neither by the status of being a smoker nor by actual smoking. Nasopharyngeal intubation with the pH electrode did not affect the swallowing frequency, but it increased salivary secretion two-to threefold for a period of 4 h. Six hours after introduction of the pH electrode and later, salivary flow was similar to baseline. It is concluded that smoking and nasopharyngeal intubation does not adversely affect the results of 24-h pH-metry.

Adult↗

PubMedDate not supplied

Neurohumoral activation in percutaneous coronary interventions: apropos of ten vasoactive substances during and immediately following coronary rotastenting.

BACKGROUND: Ischemia, left ventricular dysfunction, endothelial damage and hemodynamic changes during percutaneous coronary intervention can lead to neurohumoral activation. This may partly explain the frequent episodes of coronary spasm, hypotension and bradycardia which occur during the procedure. Rotastenting, by employing the two basic mechanisms for coronary interventions-debulking and dilatation-epitomizes percutaneous coronary interventions in general. We sought to investigate the neurohumoral changes during and immediately following coronary rotastenting. METHODS AND RESULTS: Eighteen patients undergoing elective rotablator atherectomy followed by balloon predilatation and stenting for chronic stable angina were studied. Four femoral vein blood samples were drawn from each patient at the start of the intervention (baseline), and 2 (postdebulking-2), 10 (postdebulking-10) and 60 (postdebulking-60) minutes. respectively, after the first complete passage of the rotablation burr across the whole length of lesion. Levels of 10 neurohormones, namely, endothelin-1, bradykinin, arginine vasopressin, norepinephrine, dopamine, epinephrine, angiotensin II, serum angiotensin-converting enzyme activity. atrial natriuretic peptide and kininogen were estimated in each sample. Endothelin-1 and bradykinin attained their peak levels in the postdebulking-2 samples. and the rise from 0.34+/-0.07 pmol/ml and 235.8+/-17.7 pg/ml to 0.42+/-0.06 pmol/ml and 337.2+/-41.0 pg/ml, respectively, was statistically significant (p<0.05). The level of arginine vasopressin showed a significant (p<0.05) rise from baseline (108.5+/-31.8 pg/ml) to postdebulking-60 samples (136.5+/-39.4 pg/ml). The other neurohormones did not show significant changes. CONCLUSIONS: The results suggest a definite but differential neurohumoral activation during and immediately following rotastenting. These neurohumoral changes may have a role in untoward intra- and postprocedural vasomotor and hemodynamic effects. This study establishes the concept of neurohumoral activation during percutaneous coronary interventions.

Aged↗