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Biomedical subjects

R Schellenberg

Publications and source records attributed to R Schellenberg.

At least 19 recordsLinked to original sources
PubMed2004

The fixed combination of valerian and hops (Ze91019) acts via a central adenosine mechanism.

The aim of the study was to demonstrate competition between caffeine and a fixed valerian/hop extract combination (Ze91019) by the central adenosine mechanism. EEG was used to describe the action of caffeine on the central nervous system after oral administration (200 mg) in healthy volunteers. In addition to caffeine, the volunteers (16 in each group) received either placebo or verum (2 and 6 tablets containing the valerian/hop extract). The EEG responses were recorded every 30 min thereafter. The verum medication was capable of reducing (2 tablets) or inhibiting (6 tablets) the arousal induced by caffeine. This pharmacodynamic action was observed 60 minutes after oral administration, indicating not only competition between the antagonist caffeine and the partial agonist, i. e., the valerian/hop extract but also bio-availability of the compound(s) responsible for the agonistic action. In conclusion, the valerian/hop extract acts via a central adenosine mechanism which is possibly the reason for its sleep-inducing and -maintaining activity.

Administration, Oral↗
PubMed2004

Early treatment of a migraine attack while pain is still mild increases the efficacy of sumatriptan.

To investigate the hypothesis that early treatment of a migraine attack with sumatriptan, while pain is still mild, results in higher pain free rates in comparison to delayed treatment, when pain is at least moderate, we performed a prospective, controlled and open label study. Migraineurs with or without aura who fulfilled the diagnostic criteria recommended by the International Headache Society were enrolled in the study and randomly assigned to either 'early' or 'late' treatment with sumatriptan 100 mg tablets. In the early treatment group significantly more patients were pain free at all times measured during two hours after dosing than in the late treatment group. Furthermore, patients in the early treatment group became pain free significantly sooner after dosing than patients who delayed treatment. It is concluded that migraineurs, who are able to differentiate between a migraine attack and other forms of headache, benefit from early intervention with sumatriptan 100 mg tablets.

Adolescent↗
PubMed2001

Treatment for the premenstrual syndrome with agnus castus fruit extract: prospective, randomised, placebo controlled study.

OBJECTIVES: To compare the efficacy and tolerability of agnus castus fruit (Vitex agnus castus L extract Ze 440) with placebo for women with the premenstrual syndrome. DESIGN: Randomised, double blind, placebo controlled, parallel group comparison over three menstrual cycles. SETTING: General medicine community clinics. PARTICIPANTS: 178 women were screened and 170 were evaluated (active 86; placebo 84). Mean age was 36 years, mean cycle length was 28 days, mean duration of menses was 4.5 days. INTERVENTIONS: Agnus castus (dry extract tablets) one tablet daily or matching placebo, given for three consecutive cycles. MAIN OUTCOME MEASURES: Main efficacy variable: change from baseline to end point (end of third cycle) in women's self assessment of irritability, mood alteration, anger, headache, breast fullness, and other menstrual symptoms including bloating. Secondary efficacy variables: changes in clinical global impression (severity of condition, global improvement, and risk or benefit) and responder rate (50% reduction in symptoms). RESULTS: Improvement in the main variable was greater in the active group compared with placebo group (P<0.001). Analysis of the secondary variables showed significant (P<0.001) superiority of active treatment in each of the three global impression items. Responder rates were 52% and 24% for active and placebo, respectively. Seven women reported mild adverse events (four active; three placebo), none of which caused discontinuation of treatment. CONCLUSIONS: Dry extract of agnus castus fruit is an effective and well tolerated treatment for the relief of symptoms of the premenstrual syndrome.

Adult↗
PubMed1998

Effect of the external nasal dilator Breathe Right on snoring.

This clinical trial was designed to evaluate the efficacy of the external nasal dilator Breathe Right (nasal strip) on snoring. The assessment of snoring intensity and duration as well as the sleep quality without the Breathe Right nasal strip and after application was performed in 30 out-patients with primary habitual snoring. An all-night polysomnographic investigation including registration of a17-channel EEG, EMG, respiration parameters such as breathing efforts and nasal/oral air flow, snoring vibrations, ECG, oxygen saturation, etc. was conducted in the sleep laboratory of Pro Science Private Research Clinic GmbH. The drug-free strip Breathe Right was able to reduce the maximum snoring intensity (maximum snoring vibration) throughout the night (p = 0.02, sign test), especially during the superficial sleep (sleep stage 1 and 2). The snoring intensity remained almost unchanged during slow wave sleep (SWS) and REM. In comparison with the baseline the maximum snoring intensity was reduced during the second treatment night in 22 of the 30 investigated snorers. The differentiation between snorers with and without obstructive sleep apnea and between mild and heavy snorers allowed to state that especially the snorers without apnea and the time in bed, TIB) can achieve a reduction of the maximum snoring intensity using the strip. Moreover, the number of snores per hour TIB (snoring index, SI) was reduced after application of the nasal strip for the snores with an intensity greater than 20 dB (p = 0.02, sign test). The sleep architecture remained almost unchanged, although the nasal strip led subjectively (SF-A questionnaire) to an improvement of sleep quality. The overall estimation of the subjective efficacy rating revealed that 17 of 30 patients (second treatment night) needed a certain period of time to accustom to the nasal strip. After that they could breathe easily, slept well and felt recuperated in the following morning. No adverse events were observed after adhesion of the nasal strip, except for one patient, who had the sensation as if they needed to sneeze for a short time after the first application of the nasal strip. Consequently, Breathe Right is a safe and easily applied noninvasive method to reduce the maximum snoring intensity, especially in habitual mild snorers.

Adult↗
PubMed1998

Pharmacodynamic effects of two different hypericum extracts in healthy volunteers measured by quantitative EEG.

A double-blind, randomized, placebo-controlled parallel-group trial (phase I) was performed to evaluate the central pharmacodynamic effects of two hypericum extracts with different contents of hyperforin (0.5% and 5.0%) but identical hypericin content. Three groups of 18 volunteers between 18 and 35 years of age participated in the trial. The volunteers receiving verum took 900 mg of the extract once a day for 8 consecutive days. The primary aim of this study was to observe the frequency bands, i.e., delta (1.25-4.5 Hz), theta (4.75-6.75 Hz), alpha-1 (7.0-9.5 Hz), alpha-2 (9.75-12.5 Hz), beta-1 (12.75-18.5 Hz), and beta-2 (18.75-35 Hz). This was the first study of its kind testing hypericum controlled on the basis of its hyperforin contents. A quantitative topographic EEG (qEEG) was performed on days 1 and 8 as an indicator of drug-induced pharmacological action. The volunteers' electrophysiological data were obtained prior to application and 2, 4, 6, 8, and 10 hours post administration. Plasma samples for evaluation of the pharmacokinetics of hyperforin were also obtained. The qEEG results of the placebo group on days 1 and 8 showed no significant changes with regard to their physiological daily rhythm. In both verum groups (0.5% and 5.0% hyperforin content), reproducible central pharmacodynamic effects were apparent in comparison to placebo, in particular with the extract containing 5.0% of hyperforin. A peak pharmacodynamic efficacy was observed between 4 and 8 hours post administration. These results were confirmed on day 8 of the trial. The extract containing 5.0% hyperforin showed a marked tendency to produce higher increases in qEEG baseline power performances than the one containing 0.5% hyperforin. These higher baseline outputs on day 8 were seen at the delta, theta, and alpha-1 frequency values. Compared to placebo there was a significant increase in qEEG power performance in the delta and beta-1 frequency values exclusively for the extract containing 5.0% hyperforin. The theta and alpha-1 frequency values showed a noticeable tendency more emphasized on day 8 than on day 1. Preclinical trials in rats have been observed with similar changes in the frequency bands mentioned above, especially in the cholinergic (delta), noradrenergic (theta) and serotonergic (alpha) neurotransmitter systems. These experimental findings suggest that hypericum extracts with a high hyperforin content have a shielding effect on the central nervous system.

Adult↗
PubMed1997

Functional imaging of headache - first steps in an objective quantitative classification of migraine.

A highly sensitive quantitative-topographical EEG was used in order to define first steps in an objective classification of migraine. A 17-channel quantitative EEG was recorded in 30 patients suffering from migraine with or without aura during the painfree interval. These EEG s were compared to EEGs of age related healthy norm groups using a new statistical tool called the Aberration Index. A focal aberration in the area of pain was detected in 26 out of the 30 patients mostly due to an increase of alpha1 EEG power (23 patients). Alpha2 or theta power were also increased in several patients. Furthermore, a decrease in alpha power neighbouring the focus was found in 18 patients and a contralateral reduction of alpha power was seen in 16 patients. No difference was detected between migraine with aura and migraine without aura.

Adolescent↗
PubMed1997

Pathophysiology and psychopharmacology of dementia--a new study design. 2. Cyclandelate treatment--a placebo-controlled double-blind clinical trial.

The aim of this randomized, double-blind, placebo-controlled 16-week study was to investigate the clinical efficacy of cyclandelate (Natil, 1,600 mg/day) in 139 adult outpatients with cognitive impairment (70 allocated to cyclandelate; 69 to placebo). Quantitative-topological EEG, event-related potentials (P300) and psychophysiological interview-based rating scales were used. The efficacy of cyclandelate was demonstrated in the confirmatory statistical sense using a global Hailperin-Rüger test on 10 predefined primary variables at global significance level of 0.05 relating to psychopathology, psychometry, neuropsychophysiology and behavior. At psychopathological and behavioral level the reduction of the total scores of the rating scales (Alzheimer Disease Assessment Scale, Sandoz Clinical Assessment Geriatric Scale, and Nürnberger Selbsteinschätzungs-Liste) following a 16-week therapy revealed also an individual significant cyclandelate-placebo distinction in the confirmatory statistical sense. A difference between verum and placebo was also observed by the increase of the number of correct answers during performance of the number symbol test (psychometrical level). The objective electrophysiological data (neuropsychophysiological level) support these findings. Of particular interest is that following cyclandelate treatment the absolute theta power remained almost unchanged and an increase of P300 amplitude was observed. At the same time placebo led to a distinct theta power increase and a decrease of P300 amplitude, which was interpreted as the reflection of an impairment of the initial clinical state. Summarizing, cyclandelate proved to be efficacious compared to placebo in patients with mild to moderate cognitive impairment.

Aged↗
PubMed1996

Source density analysis of functional topographical EEG: monitoring of cognitive drug action.

Electrical changes of the brain induced by mental work in the presence or absence of a drug formulation containing dimethylaminoethanolorotrate (DMAE), vitamins and minerals were analysed. Sixty elderly volunteers (30 females and 30 males; aged 40 - 65) who lacked concentration and efficiency during mental exercise according to their own opinions participated in a double-blind, placebo-controlled study. The EEG recordings were carried out before and after 12 weeks medication and were analysed according to the electrical charges at the scalp surface (Laplacian estimate) followed by Fast Fourier Transformation to obtain quantitative data. Whereas no change of electrical charge could be observed after 12 weeks of treatment in the placebo group, the verum group taking 1 capsule per day of an established drug containing a biogenic amine-vitamin combination revealed decreases in theta power during rest and increases in absolute theta power induced by mental demand within the area known to change its electrical activity during mental exercise. In the light of the current hypothesis that high theta resting power and low increases at frontotemporal brain areas during mental work indicate mental impairment, treatment with the drug under investigation was seen to successfully reverse these changes. This drug effect was localized in the frontotemporal cortex in a statistically significant manner during both the memory and the symbol recognition tests. The observed effect is fully consistent with a previous study using Fourier transformed data from conventional EEG voltage recordings. It can be concluded that an analysis of EEG data by means of the charge mode provides an excellent tool to quantify drug effects especially in cognitive research. A second perspective arises from the fact that it should be possible to recognize mental impairments at a very early stage by using this method, thus providing the possibility of an early treatment.

Adult↗
PubMed1995

Reflection of mental exercise in the dynamic quantitative topographical EEG.

The aim of this study was to investigate the activation process of the central nervous system during mental demand in a complex psychophysiological situation. A 17-channel quantitative topographical EEG was recorded in 48 healthy volunteers (male and female, aged 49 +/- 6 years), using the CATEEM system, during four different psychometric tests (simple reaction time measurement, concentration performance, figure detection and word recall test). The mental load varied with each test, producing a graduated increase in spectral power density in delta and theta frequency range on the EEG in the fronto-temporal, parietal and occipital regions of the cortex and a generalized decrease in alpha power. During the rest periods after each test a graduated increase in alpha 1 power was seen as a possible expression of change in vigilance level. With this method we were able to differentiate two effects of psychometric tests on brain activity: the actual mental demand itself and the influence on the vigilance level.

Adult↗
PubMed1995

Pathophysiology and psychopharmacology of dementia--a new study design. I. Diagnosis comprising subjective and objective criteria.

In a double-blind placebo-controlled psychopharmacological study 263 patients with cognitive impairment were screened and 137 of them were selected (following defined inclusion and exclusion criteria) to participate in a clinical trial (for results of treatment phase see part II, in preparation). The pretreatment state was evaluated twice using quantitative-topological EEG (qEEG) and psychopathological rating scales. There is a significant correlation between total score values of nearly all dementia-specific neuropsychological rating scales and absolute spectral power in the lower frequency ranges (delta, theta, alpha 1) at rest. In order to increase the diagnostic power, qEEG was recorded simultaneously with the performance in four different psychometric tests. It was found that the worse the psychopathological rating of a patient, the higher the absolute theta power at rest and the smaller the test- and demand-dependent further increase in theta power. The percentage of task-induced power increase in delta and theta frequency range appeared to be an efficient indicator for a reliable discrimination between healthy elderly individuals and demented patients (rank correlation coefficient for theta in F7: r = +0.55), which will also serve for evaluation of treatment.

Aged↗
PubMed1994

Quantitative EEG and BPRS data following Haldol-Decanoate administration in schizophrenics.

Approximately one-third of schizophrenic patients receiving antipsychotic drugs obtain little or no benefit from them. In some reports, response has been linked with "prognostic" factors, including abnormal EEG and drug response (pharmaco-EEG). Measurements of topological EEG spectral power and Brief Psychiatric Rating Scale (BPRS) values were obtained in 15 schizophrenics over a period of 20 min immediately after the first application, and at weekly intervals after single intramuscular injection of 2 ml depot haloperidol (Haldol-Decanoate). A highly significant increase in the alpha-1 power density at almost all positions and an increase in theta power at parietotemporal regions can be described as electrophysiological parameters of the acute pharmaco-EEG. BPRS values decreased continuously within the first 2 weeks followed by an increase to the predrug level after the fourth week. Over the whole observation period there was a correlation between neurophysiological data (alpha-1 power) and clinical symptomatology (BPRS total score; r = -0.7). Therefore, it can be concluded that quantitative EEG recordings are able to serve as a tool for the optimization of the depot neuroleptic treatment in schizophrenics.

Adult↗
PubMed1994

[A new method for assessment of mental performance during simultaneous, quantitative, topographical electroencephalometry and psychometry in pharmacology. Proof of the effect of a combination of biogenic amines, vitamins, minerals and trace elements].

Assessment of the Mental Performance during Simultaneous Quantitative Topographical Electroencephalometry and Psychometry in Pharmacology/Proof of influence of a biogenic amine-vitamin combination. The aim of this study was to verify the effect of a combination medicine (Vita-Gerin-Geistlich) on the human EEG pattern during psychometric (cognitive) tests given to 43 patients with poor concentration and thinking problems. A randomised, parallel, placebo-controlled double-blind study was performed. Applying 17-channel quantitative electroencephalometry and psychometric tests simultaneously this study revealed a test-dependent increase in absolute spectral EEG power in the delta and theta frequency bands, mainly observed in the frontotemporal cortex. After 8 weeks the increase in EEG power differed significantly with respect to taking placebo and verum (1 capsule/day). Verum caused a stronger rise in spectral delta and theta power, the psychometric test performance also improved. Both effects could be verified statistically. The novel EEG-controlled psychometric test set (enabling artefact-free EEG recording during psychometric tests) which was developed and used in this study represents a valid tool for future pharmacological research.

Adult↗
PubMed1993

EEG- and EP-mapping--possible indicators for disturbed information processing in schizophrenia?

1. Schizophrenic patients have been investigated electroencephalographically to describe disturbed information processing mechanisms. 2. 16-channel quantitative EEG and P300 were recorded at resting conditions before and during neuroleptic depot injection. 3. Reduced occipital alpha-power and alpha-power dependent P300-amplitudes were found in the schizophrenics. 4. Hippocampal structures are involved in the disturbed information processing mechanisms.

Adult↗
PubMed1993

Effect of phospholipase C inhibitor U-73122 on antigen-induced airway smooth muscle contraction in guinea pigs.

The importance of phospholipase C (PLC) in airway smooth muscle contraction was studied, using an inhibitor of PLC, 1-[6-[[17 beta-3-methoxyestra-1,3,5(10)-trien-17-yl] amino]hexyl]-1H-pyrrole-2,5-dione (U-73122). Tracheas from ovalbumin (OA)-sensitized guinea pigs contracted rapidly after exposure to low concentrations of antigen (OA). However, tracheas treated with U-73122 for 10 min prior to the addition of antigen, demonstrated a 3 log rightward shift in the OA dose-response curve with an IC50 of 7 microM. The analogue of U-73122, 1-[6[[17 beta-3-methoxyestra-1,3,5 trien-17-yl]amino]hexyl]-2,5-pyrrolidine-dione (U-73433), was approximately 5-fold less active in inhibiting smooth muscle contraction. In addition to the inhibition of antigen-induced smooth muscle contraction, U-73122 inhibited carbachol- and leukotriene D4-induced smooth muscle contraction. Furthermore, U-73122 inhibited in a dose-dependent manner antigen-induced histamine release from guinea pig tracheal tissue. The inhibition of smooth muscle contraction by U-73122 correlated well with the inhibition of polyphosphoinositide mediates smooth muscle contractile responses to muscarinic agonists and leukotrienes as well as antigenic-induced contraction.

Animals↗
PubMed1992

Sulfite-containing Canadian pharmaceutical products available in 1991.

OBJECTIVE: To compile an inclusive list of Canadian pharmaceutical products available in 1991 that contained sulfites. DATA SOURCES: Written and oral responses from 94 pharmaceutical companies selected from the 1989 Compendium of Pharmaceuticals and Specialties. RESULTS: A list of sulfite-containing pharmaceutical products was compiled from data supplied by the 90 responding companies. Companies whose products contained no sulfites were separately identified. CONCLUSIONS: Sulfites are present in many pharmaceutical products and are one of many excipients and additives that have been reported to cause severe adverse reactions. The provided list should be a useful aid for health care practitioners when prescribing pharmaceutical products for sulfite-sensitive patients.

Canada↗
PubMed1992

EEG-brain mapping. A method to optimize therapy in schizophrenics using absolute power and center frequency values.

In this study EEG-spectral parameters like mean alpha-power values and center frequency values are computed as maps and compared using significant probability mapping. The parameters are used to describe changes of the functional state of the brain after neuroleptic depot injection (Haldol-Decanoate) in schizophrenic patients. The absolute alpha-power increased significantly (p < 0.01), especially within the first week after injection mostly in the left hemispheric regions. The center frequency decreased most significantly (p < 0.02) between the first and second week after haldol depot injection at the right occipital regions. Both parameters are efficient to describe functional changes correlated with clinical symptomatology, even 3-5 days earlier. Thus, EEG power and center frequency mapping can be used very efficiently to estimate the optimal time between sequential neuroleptic depot injections.

Adult↗
PubMed1992

Role of ERCP and therapeutic biliary endoscopy in association with laparoscopic cholecystectomy.

Laparoscopic removal is rapidly becoming the preferred method of cholecystectomy; however, choledocholithiasis cannot usually be managed with a laparoscopic approach. Combined endoscopic sphincterotomy and laparoscopic cholecystectomy is a potential solution to this problem. To determine the feasibility of this combined procedure we studied 41 patients who had both endoscopic retrograde cholangiopancreatography (ERCP) and laparoscopic cholecystectomy. Indications for ERCP included jaundice, gallstone pancreatitis, dilated ducts on sonography, elevated liver enzymes, or stones seen on operative cholangiography. Twenty-eight patients had ERCP preoperatively. Nine patients had common duct stones; these were successfully removed from eight patients after sphincterotomy. Two patients had unexpected strictures requiring a change in surgical approach. Thirteen patients had ERCP postoperatively. Eight of those patients had common duct stones, and all were successfully removed following endoscopic sphincterotomy. Three patients had postoperative strictures, one of which was treated by endoscopic stent placement. No complications as a result of ERCP or sphincterotomy were encountered. ERCP and endoscopic sphincterotomy can be safely performed both preoperatively and as early as 1 day postoperatively. If indicators of choledocholithiasis are present, preoperative ERCP is preferred, because stone removal occasionally is unsuccessful, and cholangiographic findings may change the operative approach. Postoperative ERCP can define and, in some instances, treat biliary tract injuries resulting from laparoscopic cholecystectomy.

Adolescent↗