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Biomedical subjects

R Pohl

Publications and source records attributed to R Pohl.

At least 19 recordsLinked to original sources
PubMed2000

Increased QT variability in patients with panic disorder and depression.

This study investigated beat-to-beat QT variability in patients with panic disorder and depression, and normal control subjects using an automated algorithm to compute QT intervals. An increase in QT variability appears to be associated with symptomatic patients with dilated cardiomyopathy and also with an increased risk for sudden death. QT(vm) (QT variability normalized for mean QT interval) and QT(vi) (a log ratio of QT variance normalized for mean QT over heart rate variability normalized for mean heart rate) were significantly higher in patients with panic disorder and depression in supine as well as standing postures (P=0.002 and 0.0001 for QT(vm) and QT(vi), respectively). In another analysis, QT(vi) was significantly higher in patients with panic disorder compared to control subjects in supine as well as standing postures during spontaneous breathing as well as 12, 15 and 20 per minute breathing (P=0.005). These findings are important especially in view of the recent reports of increased risk for cardiovascular mortality and sudden death in patients with anxiety and depression and the utility of QT(vi) as a noninvasive measure of temporal repolarization lability.

Adult↗
PubMed2000

Antibiotic prophylaxis in percutaneous endoscopic gastrostomy (PEG)--results from a prospective randomized multicenter trial.

OBJECTIVE: To determine the efficacy of antibiotic prophylaxis in percutaneous endoscopic gastrostomy (PEG) as a part of a standardized regimen. METHODS: An open prospective randomised multicenter study in 216 patients. 106 received ceftriaxone 1 g i.v. 30 min preinterventionally and 110 no study medication. A standardized protocol was followed for PEG preparation, insertion, and aftercare; all patients received a 15 French gastrostomy tube. Follow-up of local and systemic infection and clinical course was continued to postintervention day 10. An aggregate erythema and exudation score > 3 or the presence of pus was taken as indicative of peristomal infection. The pharmacoeconomics of antibiotic use were also examined. RESULTS: In no-prophylaxis patients, wound infection rates were 23.6% on day 4 and 24.5% on day 10 vs. 7.6% (p < 0.05) and 11.4% (p < 0.05), respectively, in prophylaxis patients. Results were disproportionally better in tumor patients in comparison with neurological patients. Patients systemic infection rates were 11.8% vs. 1.9% in noprophylaxis vs. prophylaxis (p < 0.05), and overall infection rates 36.3% vs. 13.3%, respectively (p < 0.05). Pneumonia was more frequent in patients with underlying neurological disease and reduced in the prophylaxis group. Antibiotic and application costs were similar in both groups (p = 0.400). CONCLUSIONS: Single-dose ceftriaxone 1 g is a effective prophylaxis against local and systemic infection after PEG and should be a part of a standard regimen.

Aged↗
PubMed2000

Effect of posture and isoproterenol on beat-to-beat heart rate and QT variability.

RATIONALE: Recent literature emphasizes the utility of QT variability to study ventricular electrophysiologic function. In this investigation, we sought to test the hypothesis that beat-to-beat fluctuations in QT intervals are mediated by sympathetic activity in normal subjects using postural challenge and isoproterenol infusions. SUBJECTS AND METHODS: We obtained ECG in the supine and standing postures during spontaneous breathing, at 12, 15 and 20 per minute controlled breathing (n = 19), and before and after infusions of isoproterenol, a beta-adrenergic agent, in the supine posture during spontaneous breathing (n = 11) using lead II configuration in healthy human adult subjects. Heart rate (HR) and QT time series data were analyzed by spectral analysis of 256 s of real-time data. Beat-to-beat QT intervals were measured by automated analysis of ECG. A QT variability index (QT(vi)) was calculated for each subject as the logarithm of the ratio of normalized QT variance to normalized HR variance. We also calculated fractal dimensions of QT time series during spontaneous breathing. RESULTS: QT(vi) was significantly higher in the standing than in the supine posture (-1. 93 +/- 0.27 vs. -1.47 +/- 0.41; p = 0.0001), and also during isoproterenol infusions in the supine posture (-1.83 +/- 0.39 vs. -1. 27 +/- 0.43; p = 0.0001). Fractal dimensions of QT time series were also significantly higher during standing (p = 0.00001) and isoproterenol infusions (p = 0.0002). Respiratory rate or tidal volume did not account for the increased QT variability seen in the standing posture. CONCLUSIONS: A change from the supine to the standing posture as well as infusion of isoproterenol significantly increased the absolute as well as normalized QT variability, which appears to be due to an increase in sympathetic activity associated with these conditions.

Adult↗
PubMed2000

Effects of nortriptyline and paroxetine on QT variability in patients with panic disorder.

This study investigated beat-to-beat QT variability in patients with panic disorder before and after treatment with nortriptyline (n = 13) and paroxetine (n = 16), using an automated algorithm to compute QT intervals. An increase in QT variability appears to be associated with symptomatic patients with dilated cardiomyopathy and also with an increased risk for sudden cardiac death. QTvi (QT variability index: a log ratio of QT variance normalized for mean QT over heart rate variability normalized for mean heart rate) was significantly higher in supine posture in patients with panic disorder treated with nortriptyline (P = 0.006) but not paroxetine. Thus paroxetine may be a better drug of choice especially in patients with coexisting cardiac disease. These findings are important especially in view of the recent reports of increased risk for cardiovascular mortality and sudden death in patients with anxiety and depression. QTvi can be a valuable noninvasive measure of temporal repolarization lability, especially to study the side effects of medications which affect cardiac autonomic function.

Adult↗
PubMed1999

Confocal imaging of peripheral regions of intact rat lungs following intratracheal administration of 6-carboxyfluorescein, FITC-insulin, and FITC-dextran.

PURPOSE: This study compared the pulmonary disposition of 3 structurally diverse probe molecules following their intratracheal (i.t.) administration to anesthetized rats. METHODS: Following administration of 6-carboxyfluorescein (CF), FITC-insulin (FI) and FITC-dextran (FD), lungs were removed, inflated, perfused with a marker dye, and peripheral elements examined with confocal microscopy (CLSFM). RESULTS: At 5 min most of each probe remained within airspaces; the remainder distributed to interstitium, capillaries, Type II cells, and macrophages. At 60 min disposition differed significantly among probes. The smallest (CF, 376 Da) had almost completely exited air-spaces and was found primarily in extracellular interstitial spaces, often behind Type II cells. Disposition was consistent with both entry into peripheral lymphatics and association with peripheral fibers. FI and FD (6 and 10 kDa, respectively) were retained substantially longer within airspaces. In contrast to CF, FI appeared to localize along septal and peripheral fibers, but its disposition was inconsistent with the involvement of peripheral lymphatics. CONCLUSIONS: While all probes were < or = 10 kDa, there was considerable disparity among both their rates of absorption and subsequent disposition within peri-alveolar elements. CLSFM appears to be a useful ancillary tool for studying the pulmonary absorption of drugs and macromolecules.

Absorption↗
PubMed1997

[Primary sclerosing cholangitis with chronic pancreatitis].

HISTORY AND CLINICAL FINDINGS: A 68-year old man with insulin dependent diabetes mellitus was admitted to hospital because of diarrhoea, general weakness and 10 kg weight loss over the preceding 3 months. Biliary tract enzymes were markedly elevated (alkaline phosphatase > 1000 U/l, gamma-glutamyl transferase > 300 U/l). Computed tomography (CT) was suggestive of a space occupying lesion in the head of the pancreas. INVESTIGATIONS: CT confirmed the space-occupying lesion and biopsy revealed chronic fibrosing pancreatitis. Radiology showed the typical picture of primary sclerosing cholangitis (PSC), in addition to inflammatory changes in the pancreatic duct. TREATMENT AND COURSE: Administration of ursodeoxycholic acid and substitution therapy for the exocrine and endocrine pancreatic insufficiency normalised the laboratory values. The patient gained 5 kg and the changes in the biliary tract and pancreatic ducts markedly regressed. CONCLUSION: PSC is rarely associated with inflammatory pancreatic changes, which cause severe functional changes. Ursodeoxycholic acid improves both the biochemical changes and the histological lesions of the biliary tract and the pancreatic ducts.

Aged↗
PubMed1997

Sexual abuse history of women treated in a psychiatric outpatient clinic.

The prevalence of sexual abuse and its association with specific axis I diagnoses among 38 women patients in a psychiatric outpatient clinic were examined. Sexual abuse history was recorded in a face-to-face interview, severity of the abuse was rated on a 3-point scale, and the Structured Clinical Interview for DSM-III-R and a posttraumatic stress disorder (PTSD) scale were administered. Twenty-seven of the 38 patients (71 percent) had experienced sexual abuse. Anxiety disorders and affective disorders were the most frequent axis I disorders among the sexually abused patients. No significant relationship was found between abuse and severity of PTSD scores.

Adolescent↗
PubMed1995

Effects of isoproterenol infusions on heart rate variability in patients with panic disorder.

Some evidence suggests that patients with panic disorder have a decreased cardiac vagal and a relatively higher sympathetic activity. In this study, spectral analysis of the time series of heart rate before and after isoproterenol infusions was used to study heart rate variability in six panic disorder patients and 11 normal control subjects. These preliminary data reveal a significant increase of sympathovagal ratios only in the patient group after isoproterenol administration. The findings suggest a relative increase in cardiac sympathetic and a relative decrease in cardiac vagal function in patients with panic disorder during isoproterenol infusions.

Adrenergic beta-Agonists↗
PubMed1995

[Recall errors in locating cities on a map].

Three experiments investigated whether hindsight bias--a systematic distortion of the recollections of numerical estimates--is also observed with visuo-spatial material. Subjects estimated the location of 20 German cities on an empty map, received feedback about the true locations, and were then requested to recall their earlier estimates. Additionally, we tested each subject's intelligence, field dependency, and visuo-spatial abilities. In experiment 1, in which experimental and control items (i.e. those with and without feedback) were given to the same subjects, hindsight bias was observed, but only in one out of three dependent measures. The same pattern of results emerged in experiment 2, despite the use of a different mode of data collection. Experiment 3, in which experimental and control items were given to different subjects, found a strong hindsight bias in all three dependent measures. The personality features showed no correlation with the amount of individual hindsight bias. All three experiments provided evidence that hindsight bias occurs with visuo-spatial material.

Adult↗
PubMed1994

Lactate-induced anxiety after imipramine and diazepam treatment.

To examine the effect of treatment on lactate-induced anxiety in a controlled study, we infused 44 panic disorder patients with lactate and placebo before and after eight weeks of double-blind treatment with imipramine, diazepam, or placebo. During treatment, both imipramine and diazepam groups improved more than the placebo group. After treatment, patients in both the imipramine and diazepam groups had significantly less anxiety than the placebo patients when reinfused with lactate. In addition, imipramine decreased posttreatment panic attack frequency and diazepam decreased the perceived severity of posttreatment lactate-induced panic attacks. This study demonstrates that diazepam, like imipramine, is an effective treatment for panic disorder, and that both imipramine and diazepam blunt lactate-induced anxiety in a placebo controlled study.

Adolescent↗
PubMed1994

Sodium lactate increases sympathovagal ratios in normal control subjects: spectral analysis of heart rate, blood pressure, and respiration.

We used spectral analysis of heart rate (HR), blood pressure (BP), and respiration to examine the effects of lactate on cholinergic and adrenergic influences on HR and BP variability, a technique found to be very useful in cardiovascular research. We specifically used high frequency (0.2-0.5 Hz) and midfrequency (0.07-0.15 Hz) powers to study cholinergic and adrenergic activity in nine normal control subjects before and after lactate and placebo infusions. Our results demonstrate a marked decrease in cholinergic activity and a significant increase in sympathovagal ratios of HR modulation after lactate infusions. This altered sympathovagal balance may contribute to the panicogenic effects of lactate in panic disorder patients.

Adult↗
PubMed1994

Effects of nortriptyline on heart rate variability in panic disorder patients: a preliminary study using power spectral analysis of heart rate.

Previous reports on heart rate variability suggest that, compared to controls, panic disorder patients have a higher relative mid-frequency (MF) (0.07-0.15 Hz) power in standing posture and that they also have a greater increase in standing MF power after the administration of yohimbine. We studied the effects of nortriptyline, a tricyclic antidepressant, on HR variability measures in 13 panic disorder patients before and after successful treatment. There was a highly significant increase in supine and standing HR (p = 0.00001) while there was a significant decrease of standing absolute and relative MF power (p = 0.009 and 0.0001 respectively). This uncontrolled preliminary study suggests a decrease in sympathetic activity related to nortriptyline treatment in addition to its anticholinergic effects.

Adult↗
PubMed1993

Beta-receptor responsiveness after desipramine treatment.

To examine whether a tricyclic antidepressant affects the functional response to a beta-receptor agonist in man, the response of heart rate, blood pressure, and plasma cAMP to isoproterenol was measured in 14 normal controls taking 75 mg desipramine daily. Desipramine significantly increased the bolus dose of isoproterenol needed to increase heart rate by 25 bpm at 14-30 days but not at 3-8 days. During infusions of isoproterenol, the increase in systolic blood pressure was blunted at both 3-8 days and 14-30 days, while the decrease in diastolic blood pressure was unaffected. Blood pressure findings were not affected by preadministration of bethanechol. In ten controls, isoproterenol infusions increased plasma cAMP, but this was unaffected by desipramine treatment. These findings suggest a decrease in the functional response of beta 1, but not beta 2, receptors after treatment with desipramine.

Adult↗
PubMed1993

Intravenous sodium lactate decreases plasma GABA levels in man.

Gamma aminobutyric acid (GABA), an inhibitory neurotransmitter, may play an important role in anxiety. We studied changes in plasma GABA levels in nine healthy subjects before and after infusions of sodium lactate and dextrose. Plasma GABA significantly decreased during infusions of sodium lactate (109.3 +/- 4.4 versus 91.6 +/- 5.1 pmol/ml; P = 0.0001) but not during infusions of dextrose.

Adult↗