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At least 19 recordsLinked to original sources

PubMedDate not supplied

Effects of anxiety on emotional reactivity, performance and vigilance, in healthy volunteers.

Healthy volunteers who participate in clinical trials usually present a specific personality profile characterized by high extroversion and low anxiety traits. Herein, we examined whether anxiety traits influence performance and vigilance, as well as reactivity for six emotions (fear, anger, disgust, sadness, happiness and a neutral state), the latter being induced by the presentation of six film excerpts. Sixty-four healthy volunteers were stratified into high and low anxiety groups on the basis of their score on the Cattell and Hamilton Anxiety Scales. They were assessed on the Digit Symbol Substitution Scale (DSST), Choice Reaction Time (CRT) and Visual Analogue Scales (VAS). Their emotional reactivity was evaluated before and after each film excerpt, on responses to the Differential Emotions Scale (Izard DES). Prior to emotional induction, high-anxious subjects presented a pattern of low positive emotions and high negative emotions. After each film excerpt, emotional reactivity was more pronounced for high-anxious subjects compared with low-anxious subjects. However, there were no significant interactions between anxiety level and the values of DSST, CRT or VAS. The present findings raise the question of the relevance of selecting healthy volunteers according to their personality traits. In future studies, anxiety level will be further investigated as a factor of response variability to drugs, by examining differences in response to psychotropic drugs as a function of this factor.

Anxiety↗

PubMed2004

Judging the angles formed by visible and imaginary clock hands: a study of hemispatial effects in healthy volunteers.

Healthy, right-handed volunteers (six male, six female) either saw or imagined the hands of a clock set a particular time. In both conditions, they then judged whether the angle between the clock hands was greater than or less than 90 degrees. Subjects pressed one of two response keys to indicate their decision, and hand of response (left/right) was counterbalanced within and between subjects. The subjects had significantly longer reaction times and made significantly more errors when the imaginary angles formed by the clock hands were located in left hemispace (e.g. 8:30) than right hemispace (e.g. 4:30). With visible hands, there was no reaction time difference between visual hemifields, although significantly more errors were made when the angle formed by the hands fell within the left visual field. In the perceptual task (visible hands), reaction times and error rates increased monotonically as the distance between the hands approximated more closely to 90 degrees. This psychophysical relationship was not found in the representational task (imaginary hands). Rather, there was a significant positive correlation between reaction times/error rates and the magnitude of the number indicative of the position of the minute hand. The latter finding is consistent with the hypothesis that the lateral asymmetry in the representational task (reaction times and error rates are higher in left hemispace) is due to the time taken to mentally rotate the imaginary minute hand in a clockwise direction. No such operation is required in the perceptual condition where the hands are clearly visible.

Adolescent↗

PubMed1999

Effect of transcutaneous nerve stimulation on microcirculation in intact skin and blister wounds in healthy volunteers.

Healthy non-smoking volunteers participated in two experimental studies in which the circulatory changes induced by transcutaneous nerve stimulation (TENS) were quantified by two different methods. In experimental series 1 (intact skin), nine volunteers were given TENS on the left lower leg for 60 minutes on three occasions at different frequencies each time (2 Hz, 100 Hz, and sham). Changes in blood flow were assessed by laser Doppler imaging technique every five minutes. The mean blood flow increased by 40% during low frequency TENS and by 12% during high frequency TENS. There was no change in mean blood flow during sham stimulation. In experimental series 2 (blister wound), the circulatory changes induced by TENS were studied by intravital video microscopy and computerised image analysis in standard blister wounds on the lower leg. The microcirculatory blood flow, measured as red blood cell velocity (RBC-V) in 5-14 individual capillaries in each wound, was assessed before and during 45 minutes of TENS (2 Hz and 100 Hz). Mean RBC-V increased by 23% during low frequency TENS (n = 6) and by 17% during high frequency TENS (n = 8). The results show that: laser Doppler imaging and intravital video microscopy techniques can be used to study events at the microcirculatory level; the blister wound is an interesting new standard wound for use in clinical studies; and TENS stimulates the peripheral circulation.

Adult↗

PubMed2005

Rewarming of healthy volunteers after induced mild hypothermia: a healthy volunteer study.

OBJECTIVES: The study compares the efficacy of two active and one passive warming interventions in healthy volunteers with induced mild hypothermia. METHODS: Eight volunteers were studied in a random order crossover design. Each volunteer was studied during re-warming from a core temperature of 35 degrees C with each of: a radiant warmer (Fisher & Paykel); a forced air warmer (Augustine Medical), and a polyester filled blanket, to re-warm. RESULTS: No significant differences in re-warming rates were observed between the three warming devices. It was found that the subject's endogenous heat production was the major contributor to the re-warming of these volunteers. Metabolic rates of over 350 W were seen during the study. CONCLUSIONS: For patients with mild hypothermia and in whom shivering is not contraindicated our data would indicate that the rate of re-warming would be little different whether a blanket or one of the two active devices were used. In the field, this may provide the caregiver a useful choice.

Adult↗

PubMed1982

Effect of a modified guar gum preparation on glucose and lipid levels in diabetics and healthy volunteers.

Six healthy volunteers and 17 diabetics (6 insulin-dependent and 11 diet- and tablet-treated) were treated with a special processed, palatable guar gum (10 g b.i.d. immediately before meals) for periods of one or three weeks or, in some cases, up to 13 weeks. A standardized test meal was given to study the effect of the fiber on postprandial glucose levels. Ten g guar was stirred in water and taken immediately before the test meal. The postprandial blood glucose levels were similar in the healthy volunteers but significantly lower in the diabetics following treatment with guar for one and three weeks, respectively. Furthermore, the fasting blood glucose levels were significantly lower in the diabetics after three, but not one, weeks of treatment. The lower postprandial glucose levels were coupled with attenuated and delayed insulin levels in accordance with an effect of guar gum on the rate of carbohydrate absorption. The cholesterol levels were on average reduced with 14% in the diabetics following three weeks' treatment with guar. The higher the initial cholesterol level, the greater the reduction in cholesterol; 26% reduction was achieved in four patients with initial levels above 7 mM. The alpha-lipoprotein cholesterol levels were not significantly changed, thus an increase in the alpha-lipoprotein cholesterol/total serum cholesterol ratio was obtained. Neither plasma triglycerides nor body weights altered during treatment. The reported side-effects were as expected and were usually mild and transient (e.g. increased flatulence). The data show that guar gum also reduces postprandial glucose levels on a long-term basis and may improve the diabetic control. Additionally, treatment with this fiber leads to a concentration-dependent decrease in cholesterol levels.

Adult↗

PubMed1999

Spontaneous platelet aggregation as a predictive risk factor for vascular occlusions in healthy volunteers? Results of the HAPARG Study. Haemostatic parameters as risk factors in healthy volunteers.

The HAPARG Study (haemostatic parameters as risk factors in healthy volunteers) was performed in a subset of volunteers taking part in the MARISK Study (Mainzer Risikoindikatoren Studie für die koronare Herzkrankheit) sponsored by the German Ministry of Research and started in 1984. A previous study (Yamanishi et al., Thromb Haemostas 1985;54:539-543) had shown that spontaneously enhanced platelet aggregation as measured with the PAT-III-test and higher fibrinogen concentrations are significant risk factors for new vascular occlusions in diabetic patients. It was the aim of the HAPARG Study to establish whether spontaneous platelet aggregation and other hemostatic variables are independent risk factors for vascular occlusions in healthy volunteers. Employees of a chemical/pharmaceutical company aged 40-65 years and personnel of the University of Mainz, aged 30-60 years were included in this prospective study. Besides anamnestic data such as on smoking, hypertension and diabetes, blood pressure, the ankle/arm Doppler-index and an ECG were recorded and serum cholesterol, HDL, LDL, triglycerides, uric acid and glucose were measured. Men (1884) and women (989) entered the study and were followed for 4-6 years. In the age group of 30-50 years, more women than men were included. During the observation period 53 vascular occlusions occurred (36 coronary and nine cerebral events and eight peripheral vascular occlusions). Only three of these endpoints occurred in women. Besides age (odds ratio = 1.7, P = 0.02) and gender as expected risk factors, the multivariate logistic stepwise regression analysis revealed smoking (odds ratio = 2.2, P = 0.008), lower HDL-levels (odds ratio = 2.2, P = 0.013), elevated diastolic blood pressure (odds ratio = 1.4. P = 0.004) followed by spontaneous platelet aggregation (odds ratio = 1.1, P = 0.037), and slightly elevated blood glucose (P = 0.0047) as significant risk factors for men. Higher fibrinogen levels missed significance in this analysis (P = 0.059). None of the other hemostatic parameters showed a significant correlation with the vascular events. To our knowledge, this has been the first prospective trial in a large population of healthy individuals in which a platelet function parameter has been studied together with other possible risk factors. Spontaneously enhanced platelet aggregation is probably an independent risk factor and, like elevated fibrinogen and other haemostatic variables, an indicator of an ongoing active atherosclerotic process.

Adult↗

PubMed1995

Influence of meloxicam on furosemide pharmacokinetics and pharmacodynamics in healthy volunteers.

Fifteen healthy male volunteers participated in an open, multiple-dose study to investigate a possible interaction between furosemide and meloxicam, a new non-steroidal anti-inflammatory agent (NSAID). The study comprised three treatment periods. First, furosemide (40 mg) was administered as a single oral daily dose for 3 days. A wash-out day was followed by the administration of meloxicam (15 mg) as a single oral daily dose for 10 days. Thereafter, meloxicam and furosemide were administered concomitantly at the same doses as described above, for 3 days. The effect of concomitant ingestion of meloxicam and furosemide on furosemide-induced diuresis, urine and serum electrolytes, and furosemide pharmacokinetics was determined, after both single and repeated administration of furosemide. Estimates of the "(furosemide+meloxicam)/(furosemide alone)" mean ratio of the variable AUC(0-infinity) for plasma furosemide and the cumulative sodium excretion (0-8 h) were 97.4% (90% confidence interval 89.7-106%) and 88% (90% confidence interval 82-94%), respectively. The study results indicate that meloxicam does not affect the pharmacokinetics of furosemide in healthy volunteers, nor does it affect furosemide-induced diuresis or serum electrolytes. The cumulative urinary electrolyte excretion after concomitant administration of meloxicam and furosemide is somewhat lower than after administration of furosemide alone, in particular for the period 0-8 h after administration of furosemide. This effect of meloxicam on furosemide dynamics is small, and is probably not clinically relevant in healthy volunteers under the dosing regime studied.

Administration, Oral↗

PubMedDate not supplied

[Comparative study, using a placebo, of the frequency of micturition after repeated administration of piretanide SR 6 mg/day (Eurelix) to healthy volunteers].

Thirty healthy volunteers received piretanide SR 6 mg/day (n = 15) or placebo (n = 15) in a 10-day double-blind parallel-group comparative trial. 24-h urine output was significantly greater with piretanide than with placebo on D1 (1919 +/- 434 ml and 1160 +/- 335 ml respectively, p = 0.001 one-sided) as on D10 (1563 +/- 538 ml and 1236 +/- 435 ml respectively, p = 0.04 one-sided). Nevertheless the evolution of urinary output from D1 to D10 was significantly different (p = 0.008): it remained stable with placebo but diminished with piretanide. The diuretic effect of piretanide was apparent with a supplementary miction between 8 a.m. and 4 p.m. both on D1 and D10. Between 4 p.m. and 8 a.m., the number of mictions was the same in both groups. Thus piretanide SR 6 mg has a mild effect on the number of mictions; it should not alter patients' well-being.

Adult↗

PubMed1994

The psychomotor and cognitive effects of a new antihistamine, mizolastine, compared to terfenadine, triprolidine and placebo in healthy volunteers.

Eighteen healthy volunteers received mizolastine 5 mg, 15 mg or 45 mg, terfenadine 60 mg, triprolidine 10 mg or placebo in a 6-way crossover, double blind study. Following each dose, subjects performed a series of tests of cognitive function and psychomotor performance at 1, 3, 5, 8 and 24 hours post-dose. The test battery included critical flicker fusion, choice reaction time, tracking, Stroop and Sternberg memory tests and assessment of subjective sedation. Sedative effects and a concomitant reduction in psychomotor and cognitive function were observed following triprolidine, terfenadine and the highest dose of mizolastine, 45 mg, e.g. triprolidine reduced CFF threshold by 1.5 Hz and increased reaction time by 50 ms, impairments comparable to those caused by blood alcohol concentrations of 50 mg%, the legal limit in many countries. Mizolastine 5 mg did not differ significantly from placebo and at 15 mg differed only at one test point at one time. It may be concluded that mizolastine (5 mg and 15 mg) is free from disruptive effects on cognitive function and psychomotor performance, in contrast to terfenadine 60 mg, triprolidine 10 mg and mizolastine 45 mg.

Adolescent↗

PubMed1987

Effect of concomitant food intake on absorption kinetics of fenoldopam (SK&F 82526) in healthy volunteers.

Eight healthy volunteers participated in an open crossover study to assess the effect of a standardised meal on the systemic availability of a single oral dose of fenoldopam mesylate 100 mg. Subjects were studied on four separate occasions, twice fasting and twice fed in randomised, balanced order. Plasma and urine samples were obtained before and at regular intervals up to 25 h post dose. Measurement of fenoldopam (SK&F 82526) and its 8-sulphate metabolite (SK&F 87782) were by means of HPLC-EC analysis. Area under the plasma concentration time curve (AUC) and maximum detected plasma concentration (Cmax) for fenoldopam and SK&F 87782 were significantly reduced whereas time to maximum concentration was significantly increased with food. Using AUC's for fenoldopam and SK&F 87782, mean relative bioavailabilities were 35% and 81% respectively under fed compared with fasting conditions. Twenty-four hour excretion of fenoldopam was significantly reduced with food, but excretion of SK&F 87782 was apparently unchanged. Mean relative bioavailabilities calculated from these data were 83% and 86% respectively. Relatively large inter-subject variability in AUC and Cmax were seen, but intra-subject variability was not marked. Mild symptoms associated with vasodilation were reported on all study days.

Adult↗

PubMed1987

Effect of enoxacin on colonic microflora of healthy volunteers.

Ten healthy volunteers received 400 mg enoxacin orally twice daily for seven days. Fecal specimens were collected at 0, 2, 4, 7, 9, 11, 16 and 21 days to study the effect of enoxacin on the normal colonic microflora. On the seventh day the fecal mean concentration of enoxacin was 348 mg/kg feces. Whereas enterobacteria were strongly suppressed during the administration of enoxacin, the gram-positive and anaerobic microflora was not significantly altered. Two weeks after enoxacin was discontinued, the colonic microflora had returned to normal.

Adult↗

PubMedDate not supplied

Pharmacokinetics and metabolism of [3H]-pipethiaden in healthy volunteers.

Six healthy volunteers participated in a single-dose study of pharmacokinetics and metabolism of oral administration of [3H]-pipethiaden (1 mg). Plasma levels of total radioactivity, urinary excretion and metabolism were analyzed by liquid scintillation counting and radio-TLC. The mean peak plasma concentration of radioactive metabolites was 4.9 ng eq/ml, and the mean elimination half life was 11.5 h. 34% of radioactivity was recovered in 4 days in urine, with only 0.4% present as unchanged drug. Pipethiaden was extensively metabolized by S-oxidation, N-demethylation, and N-oxidation.

Adult↗

PubMedDate not supplied

Bioavailability of dihydroergosine in healthy volunteers.

Eight healthy volunteers received an oral dose of 10 mg and an intravenous dose of 0.75 mg of dihydroergosine. Plasma concentrations were measured by HPLC method, and some pharmacokinetic parameters were calculated. The biologic half-life in the elimination phase was 8.35 +/- 1.87 h after oral administration and 8.84 +/- 3.64 h after intravenous administration. In both cases of administration a secondary rise in plasma concentration of dihydroergosine was observed, which can be attributed to hepatic recycling. The calculated bioavailability of the drug was 9.80 +/- 2.8%.

Administration, Oral↗

PubMed1991

Effects of subcutaneously administered dermatan sulfate (MF 701) on the coagulation and fibrinolytic parameters of healthy volunteers.

Eight healthy volunteers were given single subcutaneous doses of dermatan sulfate (DS, 100, 200 and 400 mg), heparin (5,000 IU) and placebo in random order. Wash-out between treatments was greater than or equal to 10 days. Serial blood samples were taken before and up to 24 hours after treatment to measure coagulation and fibrinolytic parameters. Thrombin generation was significantly inhibited by DS and heparin as compared to placebo. The effect of DS was dose-dependent. Peak inhibition after 200 mg DS was comparable to that of 5,000 IU heparin, but lasted longer. A small, bordeline significant prolongation of APTT was observed after 400 mg DS and heparin. The changes in PAI and fibrinolytic activities were those of the circadian variation. No changes were seen in the other parameters tested. In conclusion, single s.c. doses of DS (200, or 400 mg) inhibit ex vivo thrombin generation equally or more than 5,000 IU heparin and for a longer time. The effect of both treatments on fibrinolysis is negligible.

Adult↗

PubMed1993

Plasma levels of aluminium after tea ingestion in healthy volunteers.

12 healthy volunteers on a controlled aluminium (Al) diet each consumed a tea infusion (500 ml/70 kg body weight), with either milk or lemon juice as additives, or mineral water, following a three-way crossover design. The concentrations of Al were determined in the diet, mineral water and tea infusions, and in plasma samples collected before and up to 24 hr after consumption of tea or water, using graphite-furnace atomic absorption spectrophotometry or inductively coupled plasma emission spectrometry. Consumption of up to 1.60 mg Al from tea with milk or lemon juice did not increase plasma Al levels compared with consumption of approximately 0.001 mg Al from mineral water. The results suggest that, in the short-term, drinking tea does not contribute significantly to the total body burden of Al.

Adult↗

PubMed1998

Dietary supplementation with omega 3 and omega 6 fatty acids reduces induced white blood cell aggregation in healthy volunteers.

Twenty healthy, non-smoking subjects were enrolled into a study to look at the effects of 3 months' dietary supplementation with long chain polyunsaturated essential fatty acids (EFAs) on white blood cell (WBC) aggregation. Ten subjects received 3 months' supplementation with long chain polyunsaturated omega 3 and omega 6 fatty acids, 10 received 3 months of placebo (sunflower oil). Venous blood was sampled at 0 and 12 weeks; whole blood WBC aggregation in response to formyl-methionyl-leucyl-phenylalanine (FMLP) was measured. The results showed that the 3 months' dietary supplementation with a combination of omega 3 and omega 6 fatty acids significantly reduced WBC aggregation to FMLP in healthy volunteers when compared to placebo. Since WBC aggregation to FMLP is dependent on the activity of WBC surface receptors and independent of eicosanoid production, we suggest EFAs may have other anti-inflammatory actions in addition to their role as modulators of mediator production.

Adult↗

PubMed1989

[Effects of zopiclone on sleep, daytime somnolence and nocturnal and daytime performance in healthy volunteers].

Ten healthy volunteers, aged 20 to 39, underwent 2 adaptation nights and 3 sessions of 2 consecutive experimental nights and days at 1 week intervals. In the 3 sessions, subjects received under double blind conditions either Zopiclone 3.75 mg or 7.5 mg or placebo, according to a latin-square design. On nights 1 and 2 of each session, subjects were continuously polygraphically monitored, except for a 45 min provoked wake episode 135 min after sleep onset on night 2. Sleep continuity and architecture were evaluated during night 1, degree of daytime somnolence during day 1 and residual effects during night 2 (0 h 00) and day 2 (8 h 00 and 12 h 00). Sleep continuity was not modified, except for a reduction of the number of night awakenings. NREM sleep stage 1 was reduced and stage 2 was increased (in duration but not in percentage) with Zopiclone 3.75 and 7.5 mg. NREM sleep stages 3 and 4 were increased with Zopiclone 3.75 mg only. REM sleep was reduced (in percentage only) with Zopiclone 3.75 and 7.5 mg. Daytime somnolence varied according to the time but not with the 3 different conditions. One performance test only (choice reaction time test) showed a significant impairment at 0 h 00 with Zopiclone 7.5 mg. From a subjective point of view, sleep quality was improved and night time awakening was reduced with Zopiclone 7.5 mg.

Adult↗

PubMed1996

The effects of vigabatrin on attention, concentration and mood: an investigation in healthy volunteers.

Ten healthy volunteers (six males; four females) completed this double-blind, crossover design study of vigabatrin vs placebo. Subjects were tested on four occasions; at the baselines of the placebo and the vigabatrin phase, and two weeks thereafter. At time of testing, the dose of vigabatrin was 2 g daily. Changes in cognition were assessed using the Sternberg, the PASAT, the Stroop, and Critical Fusion Flicker tests. Mood was assessed with the Mood Adjective Check List, the Beck Depression Inventory, and the Irritability, Depression and Anxiety scales. We found one drug, and one placebo, related significant difference on a measure of cognition.

Adult↗