Costs and benefits of plant allelochemicals in herbivore diet in a multi enemy world.

Sequestration of plant defensive chemicals by herbivorous insects is a way of defending themselves against their natural enemies. Such herbivores have repeatedly evolved bright colours to advertise their unpalatability to predators, i.e. they are aposematic. This often comes with a cost. In this study, we examined the costs and benefits of sequestration of iridoid glycosides (IGs) by the generalist aposematic herbivore, the wood tiger moth, Parasemia plantaginis. We also asked whether the defence against one enemy (a predator) is also effective against another (a parasitoid). We found that the larvae excrete most of the IGs and only small amounts are found in the larvae. Nevertheless, the amounts present in the larvae are sufficient to deter ant predators and also play a role in defence against parasitoids. However, excreting and handling these defensive plant compounds is costly, leading to longer development time and lower pupal mass. Interestingly, the warning signal efficiency and the amount of IGs in the larvae of P. plantaginis are negatively correlated; larvae with less efficient warning signals contain higher levels of chemical defence compounds. Our results may imply that there is a trade-off between production and maintenance of coloration and chemical defence. Although feeding on a diet containing IGs can have life-history costs, it offers multiple benefits in the defence against predators and parasitoids.

Sleep-related disorders in carpal tunnel syndrome.

INTRODUCTION: Patients with carpal tunnel syndrome (CTS) often wake up at night due to pain and numbness of affected fingers and hand. We studied the sleep disorder caused by CTS. SUBJECTS AND METHODS: 34 consecutive patients referred for operative treatment of CTS answered to a sleep questionnaire and the results were compared to a stratified random sample of 1600 Finns aged 36-50 year, whose response rate to the mailed questionnaires was 75.2% (n = 1186). Six CTS patients underwent a polygraphic sleep study before and after operative treatment of CTS. RESULTS: CTS patients reported suffering from poor sleep quality, fragmentary sleep and daytime sleepiness more often than controls. Before operative treatment of CTS there were more nocturnal body movements (p < 0.01) and awakenings lasted longer (p < 0.05) than after operation. During preoperative sleep studies no drop in median nerve conduction was detected during awakenings. CONCLUSIONS: Patients with CTS suffer from fragmentary sleep. Although patients reported waking up for the pain or numbness of hands no impairment in median and ulnar nerve conduction could be observed during these awakenings. Operative treatment of hand entrapment significantly reduced the number of nocturnal movements.

The effect of propranolol on sleep bruxism: hypothetical considerations based on a case study.

The purpose of this study was to investigate the effect of the beta-adrenergic antagonist, propranolol, on the nocturnal masseter muscle activity of a heavy sleep bruxist. Three all-night polysomnographic registrations were performed with bilateral masseter muscle EMG recordings. The first night study served as the baseline night, the second night registration was performed after total sleep deprivation and the third night registration was made with propranolol. Sleep deprivation decreased the masseter contraction (MC) index by 61% and propranolol by 72% when compared to the level of the baseline night. This preliminary observation is in line with our hypothesis suggesting a link between autonomic regulation of circulation and rhythmic activation of masticatory muscles, especially when associated with body movements during sleep.

Cardiovascular autonomic control is disturbed in nocturnal teethgrinders.

To examine the hypothesis of disturbed autonomic function, non-invasive cardiovascular reflex tests were performed on 11 sleep bruxists in the waking state. The tests included the Valsalva manoeuvre, a deep-breathing test, and an orthostatic test (standing up). The R-R intervals were monitored continuously, and blood pressure was measured non-invasively and continuously using the Finapres method. In total, 64% of bruxists showed abnormalities in at least two variables reflecting the cardiovascular autonomic function. Abnormalities were found in blood pressure regulation during the Valsalva strain, and in the immediate biphasic heart rate response during standing up, but not in the vagally mediated deep-breathing difference. These findings suggest that bruxism is accompanied by abnormalities in autonomic function, particularly in sympathetic vasoconstrictor function.

Masseter muscle activity in diagnosed sleep bruxists compared with non-symptomatic controls.

All-night polysomnographic recordings were made of clinically diagnosed sleep bruxists (n = 23) and non-symptomatic controls (n = 6). The total duration of masseter contraction (MC) episodes during sleep was 11.6 minutes per night in bruxists and 6.6 in controls (P < 0.01). The mean frequency of MC episodes was 11.0 per hour of sleep in bruxists and 6.4 in controls (P < 0.05). The mean relative amplitude of MC episodes reflecting clenching strength was 0.81 in bruxists and 0.56 in controls (P < 0.01). The percentage distribution of mixed and phasic MC episodes was 94% among bruxists and 88% in controls. The remaining activity was classified as tonic in both groups. The subclassification of rhythmic jaw movements (RJM), defined as three or more separate rhythmic contractions during MC episode were also evaluated. The frequency of those MC episodes with RJM was 3.6 per hour of sleep in bruxists and 1.1 in controls (P < 0.001). The difference in the relative amplitude between the two study groups suggests that the amount of clenching force is the primary factor responsible for the harmful effects of sleep bruxism on the masticatory apparatus. The most significant difference was seen in those phasic and mixed MC episodes which also included the subclassification of rhythmic jaw movement. The result suggests that relative amplitude and rhythmicity of MC episodes can be used as a basis to confirm the diagnosis and to evaluate the treatment effects of suspected sleep bruxists.

Abnormal lateralization of motor activity during sleep in schizophrenia.

In previous studies it has been demonstrated that during sleep healthy subjects with consistent left- or right-handedness perform about two thirds of their movements with the non-dominant hand. We examined the motor activity during waking and sleep of 13 medicated hallucinating schizophrenic patients without motor side effects and 17 control subjects using bilateral wrist actometry during two nights. Five of the patients were also monitored by continuous infrared video recording and by the Static Charge Sensitive Bed method during the movement recording nights. Lateralization to the non-dominant side during nocturnal low activity period or sleep was absent in the schizophrenic group, in which the dominant hand remained more active. This was not due to movement excess. The difference in lateralization between the controls and the patients should be considered a preliminary finding until replicated. It suggests abnormal laterality of arousal, attention or movement system during sleep in schizophrenia. It may imply abnormality in the sleep dependent modification of attentive behavior, or it may be explained by the lateralized effects of neuroleptic medication.

Progressive unilateral hypertrophic myopathy: a case study.

A 12-year-old girl had progressive unilateral muscle hypertrophy limited to the sole, tibialis anterior, and biceps femoris muscles. The affected muscles showed complex repetitive discharges by electromyography, necrosis and variation of fiber size upon histopathological examination, and increased metabolic activity in biochemical studies. The findings suggest a myopathic origin, but the actual cause remains unknown.

Individual alcohol reaction profiles.

The purpose of this study was to evaluate interindividual variation in acute reactions to ethanol. Six young, healthy female subjects participated in a double-blind experiment consisting of two identical alcohol sessions and one control session where glucose was infused instead of ethanol. Alcohol was infused in a standardized way to reach blood alcohol concentration of 1 mg/ml in 1 hr. During the 4 hr-sessions EEG-spectra, smooth pursuit eye movements, various mood variables, BAC and breath alcohol concentrations were studied repeatedly. The results showed that the subjects had a rather repeatable, individual reaction profile as expressed by changes in alpha mean frequency, theta band power, amount of corrective eye movements and subjective intoxication. The sensitivity of the subject to ethanol should thus be expressed as a reaction profile rather than as a change in a single variable.

EEG findings in tick-borne encephalitis.

EEG findings of epidemiologically and serologically confirmed tick-borne encephalitis patients were compared with findings of patients having acute encephalitis of viral or undetermined origins. Tick-borne encephalitis patients had more bilaterally synchronous bursts of slow waves and more focal abnormalities than did controls. Moreover, their EEGs remained mildly pathological, with increased slow and beta activity and intermittent focal abnormalities in some patients, whereas, EEGs in the controls became normal or borderline, usually within two months. EEG can thus reveal differences between individuals' responses to encephalitis and between different types of encephalitis, even though the clinical pictures are rather similar. Finally, the study shows that tick-borne encephalitis causes changes in the EEG that persist long after the clinical disease appears to have resolved.

Acute effects of intravenously given alcohol on saccadic eye movements and subjective evaluations of intoxication.

Effects of intravenously given alcohol on eye movements were analysed in ten voluntary subjects. Each subject served as his/her own control. Good correlations were found between the changes in saccade variables and subjective evaluations of alertness, eye movement control and intoxication. Interindividually, the subjective evaluation of drunkenness correlates with the alcohol effect on saccade variables better than do the other subjective variables or blood or breath alcohol concentrations. A steady decrease of mean and maximum velocity and a steady increase in the duration of saccades was observed during the alcohol infusion. The latency of saccades also increased. There was, however, a slight decrease of latency due to alcohol 15 min after the start of infusion, suggesting a biphasic effect of alcohol on saccade latency.

Dyskinesia and eye tracking dysfunction in young schizophrenic patients - a pilot study.

The study dealt with the occurrence of dyskinetic symptoms and disturbances in eye movements in 15 young schizophrenic patients and the effect on these disturbances of anticholinergic antiparkinsonian medication administered during neuroleptic medication maintained at a stable level. The onset of illness had occurred at a younger age in the dyskinetic patients than in the others, and they had received larger amounts of high-dose neuroleptic medication, which, however, equalled an average daily dose of only 331 mg of chlorpromazine during an average of 2 1/2 years; thus, dyskinetic symptoms can appear in young patients even during a fairly short and moderate course of medication with high-dose neuroleptics. Patients with a disturbance in smooth pursuit movement were clinically less disturbed than the others; depression, however, was more common among them. During therapy with an anticholinergic antiparkinsonian drug (Biperiden) depression worsened in patients with eye movement disturbance, while in other patients it was alleviated. The results, in fact, indicated that on the basis of disturbances in smooth pursuit movement it might be possible to distinguish among schizophrenia-group patients a depressively coloured marginal group in whom the reaction to anticholinergic medication differs from that found for patients in the nuclear-schizophrenia group.

Plasma high-density lipoprotein cholesterol in epileptics treated with various anticonvulsants.

Plasma high-density lipoprotein (HDL) cholesterol in 97 epileptics on long-term anticonvulsant therapy was investigated. Therapy with phenytoin alone or in combination with carbamazepine or phenobarbital was associated with elevated plasma HDL cholesterol levels as compared with controls. HDL cholesterol in patients treated with carbamazepine did not diverge from control values. Patients treated with phenytoin and phenobarbital in combination showed higher HDL cholesterol levels than those treated with phenytoin alone. There was an inverse correlation between the HDL cholesterol and serum triglyceride levels. The results demonstrate that high plasma HDL cholesterol might be associated with therapy involving some anticonvulsants known to be potent enzyme inducers. This suggests that the elevation of HDL cholesterol during therapy is probably related to the drug-caused enzyme induction phenomenon.

Acute effects of alcohol on saccadic eye movements.

Four components of 20 degrees horizontal saccadic eye movements, i.e., latency, mean and maximum velocities, and duration were measured in 16 students under the influence of alcohol and also in a control situation. The experimental procedures were standardized and automated as much as possible. Latency (simple eye reaction time) was not influenced by alcohol in blood concentrations of 0.056--0.116%. Mean and maximum eye velocities decreased by about 9% and duration of saccades increased by 11%. The maximum changes occurred 90--120 min after the start of alcohol ingestion. The changes in velocities and durations correlated more closely with feelings of intoxication than with blood alcohol concentrations. There were great intra- and intersubject variations in reactions to alcohol. The close resemblance between the effects of certain psychotropic drugs, alcohol, fatigue, and decreased attention on eye movement control suggest that all these may act upon the same nervous structures in the brain stem.

Acute effect of small doses of alcohol on the NSD parameters (normalized slope descriptors) of human EEG.

The acute effect of ethanol upon the NSD (normalized slope descriptors) or Hjorth parameters of EEG were analyzed in 11 students. The maximal blood-alcohol concentration ranged from 1.0--1.7 mg/l. The activity (mean amplitude) increased and the complexity (frequency spread) decreased significantly as a function of time. The same effect was seen in control subjects, but to a lesser degree. The difference between the test and the control group was, however, significant only for the change in complexity. Changes in the mobility parameter (mean frequency) showed most prominently the interindividual differences: in some a transient increase during increasing blood-alcohol concentration, in others a steady falling tendency. It is concluded that changes in the NSD parameters reflect (1) the depressing effect of both alcohol and the test situation, which was more or less evident in most subjects, and (2) the individual degree of and type of CNS reaction to alcohol consumption. From a social and psychologic point of view, the individual reactions are at least as important as the reactions common to all.

Taurine transport rates between plasma and tissues in adult and 7-day-old mice.

Transport rates for taurine from plasma to liver, kidney, heart, spleen and femoral muscle were evaluated in adult and 7-day-old mice in vivo. The mice were injected with [35S]taurine and the specific radioactivity of taurine was determined in the above tissues at varying intervals from 10 min up to 48 hr after the injection. A multicompartment model was fitted to the data and the transport rates with their confidence limits were estimated using a digital computer. The tissue-plasma exchange rate was generally faster in adult mice than in 7-day-old mice. The transport rates between the plasma and the brain or muscle were low, while taurine penetrated into the liver and kidneys very rapidly. There was no distinct correlation between the calculated transport rates and the tissue taurine concentrations. The metabolic breakdown of taurine in the tissues was slow, since only negligible amounts of radioactivity were recovered in the metabolites of taurine, isethionic acid and inorganic sulphate. It seems unlikely that either the magnitudes of the transport rates between the plasma and the tissues or taurine breakdown rates in situ act as the primary factor determining the taurine levels in tissues.