The effect of repeated exposure to fruit drinks on intake, pleasantness and boredom in young and elderly adults

The effect of a repeated monotonous exposure on ad libitum intake, pleasantness and boredom in elderly people in a real life situation is unclear. We therefore investigated the effects of repeated exposure to ad libitum intake of three orange-based drinks on boredom and acceptance in young and elderly people. Young (n=32) and elderly women (n=36) participated in a randomized within subjects cross over trial with three intervention periods of 12 days each followed by a 2-day wash out period. During each intervention period, the participants received 1 L of one type of drink per day. The three drinks varied in sweetness intensity. Intake was measured by weighing the returned packets and pleasantness, boredom and sweetness were rated on a 10-point scale. For the young women, mean consumption of the three drinks (p<0.01) and pleasantness decreased (p<0.01) and boredom increased (p<0.001). For the elderly women, consumption increased (p=0.03) whereas pleasantness (p=0.34) and boredom (p=0.40) were stable. In the young women, the orange peach drink which had the highest sugar content contributed the most to the effect of the repeated exposure. The consumption and pleasantness ratings for this drink decreased (r=-1.05, p=0.01 and r=-0.07, p=0.007, respectively) and boredom increased (r=0.12, p<0.001). In conclusion, elderly women experienced no increased boredom whereas young women did.     

Arm load magnitude affects selective shoulder muscle activation

For isometric tasks, shoulder muscle forces are assumed to scale linearly with the external arm load magnitude, i.e., muscle force ratios are constant. Inverse dynamic modeling generally predicts such linear scaling behavior, with a critical role for the arbitrary load sharing criteria, i.e., the “cost function”. We tested the linearity of the relation between external load magnitude exerted on the humerus and shoulder muscle activation. Six isometric force levels ranging from 17 to 100% of maximal arm force were exerted in 24 directions in a plane perpendicular to the longitudinal axis of the humerus. The direction of maximum muscle activation, the experimentally observed so called Principal Action (PA), was determined for each force magnitude in 12 healthy subjects. This experiment was also simulated with the Delft Shoulder and Elbow Model (DSEM) using two cost functions: (1) minimizing muscle stress and (2) a compound, energy related cost function. PA, both experimental (PA_exp) and simulated (PA_sim), was expected not to change with arm forces magnitudes. PA_exp of the mm. trapezius pars descendens, deltoideus pars medialis and teres major changed substantially as a function of external force magnitude, indicating external load dependency of shoulder muscle activation. In DSEM simulations, using the stress cost function, small non-linearities in the muscle force–external load dependency were observed, originating from gravitational forces working on clavicular and scapular bone masses. More pronounced non-linearities were introduced by using the compound energy related cost function, but no similarity was observed between PA_exp and PA_sim.     

Is melatonin helpful in stopping the long-term use of hypnotics? A discontinuation trial

Objective To find out if administration of melatonin facilitates discontinuation of benzodiazepine (BD) therapy in patients with insomnia. Method A placebo controlled trial in nine general practices in the Netherlands. Long-term users of benzodiazepines were asked by their GP to participate in a discontinuation program in combination with melatonin or placebo. The intervention and follow-up period lasted one year. During this period participants received four questionnaires about their use of sleeping medication and several health instruments. The urine of all participants was tested for the presence of benzodiazepines, as proof of the discontinuation. Main outcome measure The discontinuation of benzodiazepine use measured by questionnaires and urine samples at three assessment points. Results A total of 503 long-term users were selected by the GPs, of whom 38 patients (16M/22F) participated. After one year 40% had stopped their benzodiazepine use, both in the intervention group on melatonin and in the placebo control group. Comparing stoppers and non-stoppers did not reveal significant differences in benzodiazepine use, or awareness of problematic use. Conclusion Our findings do not conclusively indicate that melatonin is helpful for the discontinuation of the use of benzodiazepines, but the average dose of benzodiazepines in the group was low. Further investigation is necessary, with special attention to the possible influence of the daily dose on the facilitation effect of melatonin. Frans H. J. A. Vissers passed away in September 2006     

Trisomy 16 confined to the placenta.

Two cases with trisomy 16 confined to the placenta are presented. Prenatal diagnosis was indicated because of fetal growth retardation. In case 1, a phenotypically normal but small-for-date boy was born. In case 2, the fetus turned out to be triploid on cordocentesis. In both instances the trisomy 16 was recovered from the placenta. Recovery indicates that the abnormality was present in the placenta during the time of fetal growth retardation, which supports an aetiological relationship. Strict appliance of the current models cannot readily explain the observed discrepancies. In case 2, a chimeric placenta as a result of a vanishing twin is assumed. Cases of placental trisomy 16 published after 1988 are reviewed. It is concluded that confined placental trisomy 16 can cause intrauterine growth retardation if present in both the direct preparation and the villus culture. The chances of finding a chromosomally abnormal fetus (mosaic trisomy 16, triploidy) after diagnosis of trisomy 16 in chorionic villi are low but warrant further investigations.     

The effect of visual field defects on eye movements and practical fitness to drive

Eye movements of subjects with visual field defects due to ocular pathology were monitored while performing a dot counting task and a visual search task. Subjects with peripheral field defects required more fixations, longer search times, made more errors, and had shorter fixation durations than control subjects. Subjects with central field defects performed less well than control subjects although no specific impairment could be pinpointed. In both groups a monotonous relationship was observed between the visual field impairment and eye movement parameters. The use of eye movement parameters to predict viewing behavior in a complex task (e.g. driving) was limited.     

Stress susceptibility as a determinant of the response to adrenergic stimuli in mesenteric resistance arteries of the rat

Characterized by the behavioral response to apomorphine, two outbred lines of Wistar rats can be recognized with constitutionally determined high (apomorphine susceptible, APO-SUS) or low (apomorphine unsusceptible, APO-UNSUS) adrenal responses to similar environmental stress. Within the accumbens nucleus, the APO-SUS and APO-UNSUS rats differ in alpha -adrenergic receptor responsiveness. This study explored whether these differences in adrenergic receptor sensitivity also exist in mesenteric resistance arteries. A Mulvany myograph was used to study the vasomotor responses of isolated mesenteric resistance arteries to adrenergic receptor stimulation. Phenylephrine (alpha1-agonist)-induced vasoconstriction did not differ between the two lines (pEC : 5.8 +/- 0.05 microM versus 5.8 +/- 0.04 microM and Emax: 36 +/- 2 kPa versus 33 +/- 1 kPa for APO-SUS, n = 9, and APO-UNSUS, n = 11, respectively, p > 0.1). After precontraction with phenylephrine, salbutamol (beta -agonist)-induced relaxation was less in APO-SUS rats (pEC50 4.9 +/- 0.06 versus 5.3 +/- 0.06M for APO-SUS, n = 9, and APO-UNSUS, n = 7, respectively, p < 0.001). Likewise, clonidine (alpha2-agonist)-induced relaxation was reduced in APO-SUS rats (pEC50: 6.7 +/- 0.07 versus 7.0 +/- 0.04, for APO-SUS, n = 9, and APO-UNSUS, n = 8, respectively; p < 0.01). In conclusion, constitutionally determined high susceptibility to stress is accompanied by an impaired vasorelaxation to adrenergic stimuli whereas vasoconstriction is unaffected. An unopposed vasoconstrictor action of norepinephrine may place the APO-SUS rats at increased risk for the development of hypertension, insulin resistance, and atherosclerosis.     

Certification and quality assurance in Dutch occupational health services

Since 1994, each Dutch enterprise has to be affiliated to an independent occupational health service (OHS), recognized by the government. In addition, each enterprise has to be supported by this occupational health service in its activities for the improvement of working conditions, and in the guidance of employees absent from work. From 1994 to 1998, the government was carrying out the certification and recognition of occupational health services. Since 1998 the certification has been carried out by private certifying institutions, in general consultancy bureaus that also provide ISO certification. In the Netherlands, the supervision of the quality of occupational safety and health care is twofold. Firstly, the Labor Inspectorate is checking if the enterprises keep to the rules. For example, each enterprise should have a risk assessment report at its disposal. The latter should be approved by the OHS. If an enterprise does not meet these rules, a penalty may be imposed. In practice, this happens rather seldom. Secondly, each OHS unit should be recognized by the Ministry of Social Affairs and Employment. The recognition takes place if the private certifying institution has assessed that the OHS meet a large number of requirements laid down in the "Guideline for the Certification of Occupational Health Services". This Guideline consists of 50 conditions and about 200 verification points. The requirements deal with the internal organzation and the output. By order of the Dutch government the IVA, a Dutch institute for social research, has recently investigated if this certification leads to a sufficient guarantee for appropriate occupational safety and health care. By means of a large number of discussions and workshops, the IVA has investigated how OHS, employees, employers, insurance companies and others judge the quality management. In this study, the current method of certification turned out to produce insufficient incentives for quality improvement. None of the involved parties turned out to be satisfied with the current system. The fundamental problem of this certification system can be summarized as follows. The requirements prescribe a quality management system in conformity with ISO, but they also contain a lot of organization rules, much more than ISO. It is this degree of specification that, if practiced slavishly, leads to an output that is not able to satisfy the needs and demands of employers, employees and government. There are no rules with regard to this output, but only to the process, e.g. the way an advice has been brought about. In this paper, we show how the current certification system is working, how this system has been evaluated, and what criticisms have been uttered. We also indicate how we might achieve a real improvement of quality management in prescribing much less details about the OHS internal organization, and in demanding employers and employees to make clear agreements about the desired OHS output and to monitor carefully if the agreed output quality has been achieved.     

Genetic polymorphisms modify the response of factor VII to oral contraceptive use: an example of gene-environment interaction

Elevated plasma levels of factor VII and fibrinogen are risk factors for cardiovascular disease, especially arterial thrombosis. Oral contraceptive use increases factor VII and fibrinogen plasma levels. It has been described that DNA polymorphisms are associated with the plasma levels of hemostatic variables and their regulation. The R/Q353 polymorphism in the factor VII gene and the -455G/A polymorphism in the fibrinogen beta-gene are associated with plasma levels of factor VII and fibrinogen, respectively. We analysed data of a randomised study (n = 95) in which two types of oral contraceptives were compared with regard to their effect on factor VII and fibrinogen, in which we also determined R/Q353 and -455G/A polymorphisms. Women were allocated randomly to either receiving a monophasic oral contraceptive containing 75 micrograms of gestodene and 20 micrograms of ethinyl estradiol, or 150 micrograms of desogestrel and 20 micrograms of ethinyl estradiol. Blood was taken before treatment and after 3 and 6 months of oral contraceptive use. Factor VII and fibrinogen increased significantly after 3 and 6 months of oral contraceptive use; the increase in factor VII was higher in the desogestrel group than in the gestodene group at 3 and 6 months. For fibrinogen, there were no intergroup differences at 3 and 6 months. At baseline, an association between genotype and plasma factor VII and fibrinogen levels was observed. In multivariate analysis, the R/Q353 polymorphism and the type of oral contraceptive were determinants of the effect on the change in factor VII, with the highest increase in women carrying the Q allele and using the desogestrel-containing oral contraceptive, and the lowest increase in women with the RR genotype who use the gestodene-containing oral contraceptive. For fibrinogen, no interaction among type of oral contraceptive, -455G/A polymorphism, and change in plasma levels was observed. We conclude that an individual's genetic variation may contribute to the response of plasma factor VII to oral contraceptive use.