Biomedical subjects
R Pohl
Publications and source records attributed to R Pohl.
5-HT1A partial agonists. What is their future?
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Effects of isoproterenol in panic disorder patients after antidepressant treatment.
Fourteen panic disorder patients were infused with isoproterenol both before and after treatment with tricyclic antidepressants. Thirteen patients had panic attacks before treatment, and only 2 after treatment. There was a significant decrease in anxiety as measured by a Panic Description Scale during posttreatment infusions, and patients were able to tolerate longer infusions posttreatment. Isoproterenol increased systolic blood pressure and decreased diastolic blood pressure in both untreated patients and in 10 normal controls. Tricyclic antidepressant treatment of panic disorder patients abolished isoproterenol-induced increases in systolic blood pressure, but did not affect diastolic blood pressure response. These changes are consistent with a decrease in sensitivity to beta-1 receptor stimulation after treatment with tricyclic antidepressants.
Effect of imipramine treatment on changes in heart rate and blood pressure during postural and isometric handgrip tests.
Postural and isometric handgrip tests were performed on nine patients with panic disorder and 13 patients with major depression before and after treatment with imipramine for a mean duration of 10 weeks. There were significant increases in resting supine heart rate (HR), systolic, diastolic and mean blood pressures (SBP, DBP, MBP) after treatment. There were significant increases in HR and DBP after standing from supine posture before treatment, and after treatment, there was a significant enhancement of this tachycardia. The decrease of heart rate during the change from standing to supine posture before treatment significantly decreased further after imipramine treatment. Decreases in SBP and DBP during the change from standing to supine posture were significantly smaller during the post treatment condition. Increases in SBP during the standing isometric exercise test were smaller after treatment. These findings suggest abnormal orthostatic reflexes secondary to an altered adrenergic function and/or cholinergic supersensitivity after treatment with imipramine.
Somatic and psychological symptoms during isoproterenol-induced panic attacks.
To determine which symptoms characterized isoproterenol-induced panic attacks, we analyzed the presence of panic attacks in 54 panic disorder patients who panicked, 24 patients who did not panic, and 37 controls who did not panic during isoproterenol infusions. The increases over the baseline of the symptoms shortness of breath and fear of going crazy were highly associated with panicking patients when compared to nonpanicking patients and nonpanicking controls. The increases of the symptoms trembling and shaking, generally nervous, and fear of going crazy were highly associated with patients when compared to controls. The possibility of a cognitive theory of panic attacks is discussed.
Increased serum total cholesterol to HDL-cholesterol ratio after imipramine.
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Lactate-induced panic and beta-adrenergic blockade.
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Lorazepam vs. alprazolam in the treatment of panic disorder.
Sixty-seven patients with panic disorder were treated with single-blind placebo for one week before being randomized to 6 weeks of double-blind treatment with either lorazepam or alprazolam. Both drugs showed significant and comparable antipanic efficacy throughout the course of the study. With the exception of sedative effects, both drugs were well-tolerated at a mean daily dose of 7 mg for lorazepam and 3 mg for alprazolam. Lorazepam appeared to be as effective as alprazolam in the acute treatment of panic disorder.
Heart rate and blood pressure: significance of the law of initial values.
Thirty normal controls, 30 panic-disorder patients and 19 depressed patients participated in a study involving postural and isometric handgrip tests. Prestimulus values of heart-rate and blood-pressure were correlated with stimulus phasic responses. The law of initial values did not hold during the change from supine to standing posture or during the isometric handgrip test for heart-rate and blood-pressure, but it held for heart-rate during the change from standing to supine posture. The effect of regression toward the mean was accounted for in the analyses.
Decreased R-R variance in panic disorder patients.
To investigate autonomic function in panic disorder patients (n = 30), we compared postural changes in heart rate and the R-R interval variance in patients and normal controls (n = 20). There was no significant difference in the immediate changes in heart rate upon standing between the groups. R-R variance was significantly decreased during resting supine condition in patients as indicated by the corrected standard deviation of the R-R intervals. The standing R-R variance was significantly lower than that of normal controls as indicated by the corrected standard deviations, the corrected mean consecutive difference and the corrected standard deviation of the mean consecutive difference of the R-R intervals, suggesting an increase in vagal withdrawal in patients, especially upon standing. If this finding is specific to panic disorder patients, it may be a useful peripheral marker for this condition.
Heart rate and blood pressure changes during postural change and isometric handgrip exercise in patients with panic disorder and normal controls.
Changes in heart rate (HR) and blood pressure (BP) were measured serially during postural changes and isometric hand grip exercise test (IHT) in 30 patients with panic disorder and 30 normal controls. Though there were no significant differences in the delta increase of HR or systolic or diastolic BP during these tests, the resting supine and standing diastolic BP were significantly higher in panic disorder patients than in controls. The standing mean BP was also significantly higher in panic disorder patients. These findings are suggestive of an increase in adrenergic tone in panic disorder patients.
Ingestion of Giardia lamblia trophozoites by murine Peyer's patch macrophages.
Macrophages in Peyer's patches are important in the initiation of gastrointestinal immune responses to enteric pathogens. To examine their potential role in giardiasis, murine mononuclear cells were isolated from collagenase-treated Peyer's patches by their adherence to glass. These cells were incubated with Giardia lamblia trophozoites in the presence of nonimmune or immune (anti-Giardia antibody titer, greater than or equal to 1:1,024) mouse serum. Macrophages ingested trophozoites at low levels when they were incubated with nonimmune mouse serum. Ingestion was significantly increased at all time points (P less than 0.01) when cells and parasites were incubated in 5% immune mouse serum; the number of Giardia trophozoites ingested per 100 macrophages was 21.6 +/- 7.1 (standard error of the mean) at 1 h and increased to 59.0 +/- 16.4 at 8 h. Electron microscopy documented trophozoite destruction within macrophages. Association of G. lamblia with macrophages elicited an oxidative response; 50.9 +/- 3.6% of macrophages with trophozoites attached or ingested reduced the dye Nitro Blue Tetrazolium, compared with 13.0 +/- 5.2% for cells without associated trophozoites (P less than 0.04). These results demonstrate that macrophages are capable of ingesting G. lamblia in vitro and may play an important role in host defense in giardiasis.
Lactate induced panic and beta-2 adrenergic activation.
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Monosodium glutamate and tranylcypromine administration in healthy subjects.
The authors administered 400 to 1600 mg of monosodium glutamate and placebo to five healthy males while they were medication-free and again while they were receiving the monoamine oxidase inhibitor tranylcypromine, after having received the drug daily for at least 2 weeks. Monosodium glutamate produced no consistent changes in either blood pressure or heart rate in subjects receiving tranylcypromine. Spontaneous hypertensive episodes were observed in two subjects. These blood pressure increases also occurred with tranylcypromine alone and were unrelated to monosodium glutamate administration. Diet was not violated during these episodes.
Effect of imipramine on liver function tests.
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Low serum iron levels and tricyclic antidepressant-induced jitteriness.
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Lactate infusions in panic disorder patients and normal controls: autonomic measures and subjective anxiety.
The anxiety symptoms, heart rate and blood pressure of 61 patients who panicked during lactate infusions were compared with 25 control nonpanickers. There was no significant difference in the increase in heart rate and blood pressure over baseline between patients and controls. There appeared to be no significant correlation between the subjective anxiety ratings and the measures of heart rate and blood pressure during lactate-induced panic. The symptoms of shortness of breath, feeling frightened or afraid, feeling dizzy and fear of losing control were significantly associated with lactate-induced panic. In addition, the cognitive symptoms of fear of losing control and fear of going crazy appear to be important determinants of lactate-induced panic.
History of separation anxiety in patients with panic disorder and depression and normal controls.
The frequency and severity of separation anxiety for subjects with panic disorder and major depression was compared with that for normal controls. The subjects were diagnosed according to DSM-III criteria. Each subject completed a questionnaire consisting of 9 items derived from DSM-III criteria for separation anxiety disorder. The incidence of separation anxiety and its severity were significantly higher for the panic disorder subjects than for normal controls but there was no significant difference between depressed and panic disorder subjects. Panic disorder subjects with a history of separation anxiety disorder had a significantly earlier onset of panic attacks.