Motion sickness--vestibular habituation with the centrifuge

People who are prone to motion sickness have a directional preponderance of nystagmus to the left. Centrifuging will change this preponderance to the right in most people, and at the same time reduce their tendency towards motion sickness but only with regard to air travel.     

Standardization of allergenic extracts of Aspergillus fumigatus. Liberation of IgE-binding components during cultivation

During cultivation of Aspergillus fumigatus a rapid liberation of IgE-binding components was found reaching maximum values during the logarithmic phase of growth (phase I). After a fall in IgE-binding titers during phase II, appearance of additional IgE-binding components was noted during the period of lysis of the microorganism (phase III). These latter allergenic components are different from the phase I IgE-binding components, as was shown by crossed-inhibition studies. The number of precipitating antigenic components was not related with the corresponding IgE-binding titers and showed an increase during all phases of growth. The rapid changes in both IgE- and IgG-binding properties and the discrepancies between precipitating properties and IgE binding are discussed in relation to standardization and quality control of aspergillus extracts.     

Local pharmacological manipulations of prefrontal dopamine affect conflict behaviour in rats

Several lines of research have implicated the prefrontal cortex (PFC) and its dopaminergic (DA) innervation in an animal's response to stress and anxiety. To extend these findings we evaluated the effects of bilateral infusions of DA drugs into the medial PFC of rats, in a modified conflict test, consisting of Reward, Conflict and Time-out components. In experiment 1, the effects of infusions of the DA receptor agonist apomorphine (APO) were compared to the effects of systemic injections of the same drug. APO infusions induced a dose-dependent decrease of responding in the Conflict component, indicative of an anxiogenic-like effect. However, response rates in the Reward component were simultaneously decreased, casting some doubt on the specificity of the effect. In comparison, i.p injections of APO in a second group of animals did not affect responding in the Conflict component, but dose-dependently decreased response rates during Time-out and Reward components. In experiment 2, we evaluated the effects of infusions of APO and the DA receptor antagonist cis-flupenthixol (FLU) into the medial PFC in the conflict test, and in one of its variants, the extinction of conflict test. Although both APO and FLU decreased response rates during Reward components, responding in the Conflict components of both tests was differentially affected. APO infusions decreased Conflict responses, the effect being more pronounced in the extinction of conflict test. In contrast, infusions of FLU increased responding in the Conflict components. The respective pro- and anti-conflict effects of APO and FLU infusions are in favour of a direct involvement of prefrontal DA in anxiety-related behavioural responses.     

Chronic infusion of clonidine does not alleviate spontaneous morphine withdrawal symptoms in rats

Opiate withdrawal is associated with behavioural symptoms and a sympathetic hyperactivity, the latter being sensitive to clonidine. The central question is whether behavioural symptoms would be also sensitive to clonidine. A rat model was used in which the locomotor activity was measured 24 h a day during the morphine withdrawal phase. Spontaneous withdrawal of morphine reduced strongly the high nocturnal locomotor activity, concomitently decreasing food intake and body weight. Chronic infusion of clonidine (30–120 µg/kg/day) using osmotic minipumps had no effect on the withdrawal symptoms. Higher dosages (250–1000 µg/kg/day) potentiated rather than alleviated the withdrawal symptoms, suggesting an ₁-adrenergic effect of clonidine rather than an ₂-action. Therefore, we studied the action of a more specific ₂-agonist UK-14.304. UK-14.304 was less potent than clonidine in naive animals. It slightly alleviates the decrease of nocturnal activity during spontaneous morphine withdrawal. Furthermore, we have tested whether the effects of high dosages of clonidine could be altered by a specific ₁-antagonist doxazosine. Doxazosine reduced only slightly the potentiation in the decrease in food intake by clonidine during morphine withdrawal. For the other symptoms no interaction between doxazosine and clonidine was found. The data suggest that the use of clonidine in the detoxification of opiate dependent people is based on the suppression of the sympathetic hyperactivity rather than on symptoms with a more behavioural character.     

Aortico-right ventricular tunnel: prenatal diagnosis leading to neonatal survival

In the 36th week of gestation a large aortico-right ventricular tunnel with an otherwise structurally normal heart was diagnosed by fetal echocardiography. This report describes for the first time the impact of the timely prenatal diagnosis of an aortico-right ventricular tunnel followed by successful management in early infancy.     

Decrease of CD4+CD25+ T cells in peripheral blood after liver transplantation: association with immunosuppression

CD25 (IL-2 receptor alpha-chain) marks a population of CD4-positive T cells with a suppressor phenotype. These CD4+CD25+ regulatory T cells can suppress both effector T cells and antigen-presenting cells and have been identified as a principle regulator of tolerance in experimental transplantation models. In the setting of human liver transplantation, however, little is known about the dynamics of these cells in relation to rejection, tolerance, and immunosuppression. In the current study we determined CD4+CD25+ T cell in blood of liver transplant recipients using flow cytometry and investigated a possible link with immunosuppressive therapies. Peripheral blood mononuclear cells (PBMC) of 27 liver transplant patients (pretransplantation and 12 months posttransplantation) and 16 healthy controls were included. We found that the percentages of CD25+ cells within the CD4 T-cell population was significantly reduced in more than two-thirds of patients 1 year after transplantation. Also the total percentage of CD4-positive T cells declined significantly within this period, making the absolute reduction of regulatory T cells after transplantation even more profound. Comparing PBMC samples of patients and healthy controls revealed an increased percentage of CD4+ T cells in the patients before transplantation, probably related to the chronic liver illness. The reduction in CD4+CD25+ T cells after transplantation was similar for different immunosuppression regiments. All patients, however, received calcineurin inhibitors, suggesting a possible suppressive effect of this therapy on regulatory T-cell levels in peripheral blood. Currently, assays for regulatory T-cell activity are used to further support this hypothesis.     

P-100 in the treatment of Ménière's disease: a clinical study

Patients suffering from Ménière's disease are particularly sensitive to negative pressure in the middle ear. For example, attacks of vertigo can be triggered by a descent in an aircraft when ventilation of the middle ear can become critical. Positive-pressure pulse treatment has been shown to have a beneficial effect on the symptomatology and is now a true alternative in the treatment of Ménière's disease. In this study, we compared two devices that produced positive-pressure pulses delivered to the inner ear via the external ear canal and after the insertion of a middle-ear ventilation tube. Both devices (Meniett and P-100) were equally successful and confirmed that positive-pressure pulse treatment is a true alternative to current treatment modalities. However, the P-100 is the preferred device, particularly for its convenience of use and its cost, which is considerably lower.