Movement-related potential measures of different modes of movement selection in Parkinson's disease

Movement-related potentials were recorded preceding self-paced voluntary movements in patients with Parkinson's disease and in healthy subjects of the same age group. We compared the Readiness Potential preceding joystick movements in a fixed direction and preceding joystick movements in freely selected directions. In normal subjects the Readiness Potential amplitude was higher preceding freely selected movements than preceding movements in a fixed direction. The Readiness Potential in Parkinson patients failed to be modified by the different modes of movement selection. The modulation of the Readiness Potential by different ways of preparing for movement might be due to the supplementary motor area (SMA) being more strongly engaged by tasks requiring internal control of movements than by tasks that are externally structured. The results suggest that this task-dependent variation of SMA activity is reduced in Parkinson's disease. A failing capacity to adapt SMA activity to different task demands has previously been suggested by evidence from positron emission tomography studies using similar tasks.     

The maturation of the central auditory conduction in preterm infants until three months post term. III. The middle latency auditory evoked response (MLR)

Middle latency auditory evoked responses (MLRs) were recorded in 64 premature infants; serially in 54 of them. The last recording sessions occurred at 50-52 weeks conceptional age (CA), defined as the gestational age (GA) added to the chronological age. The MLRs were analyzed for the components PO, Na and Pa, and the interpeak latency difference (IPLD) Na-PO. The detectability rate of PO and Na reached 80-90% at about 30 weeks CA. Pa reached the highest rate of about 60% at 52 weeks CA. The degree of prematurity did not result in clear differences with respect to the parameter values. Also, the side of stimulation did not influence the MLR parameter values. The latency values of the MLR components are strongly age dependent. Topographic differences were found between the sides ipsi- and contralateral to stimulation. They are, however, different for PO, Na and Pa. The influence of the state of vigilance on the parameter values could generally only be established at CA levels of about 32 and 52 weeks CA. The amplitude values at 52 weeks CA are especially sensitive for sleep or awake state. The particular pattern of age dependency of the different components and their topographic differences are consistent with a differential generation of bilateral nature. The early appearance of the response supports the generation of an early functioning subcortical structure in the auditory pathway.     

Falsification of Thai dianabol.

The use of drugs to enhance performance in sport will continue despite drug testing procedures and information campaigns. No attention is paid to the quality of these illicit drugs, as they are obtained through a circuit not monitored by the official authorities. A falsification of 'Thai Dianabol', an anabolic steroid, is reported. The tablets contained methyltestosterone and clenbuterol instead of methandrostenolone. Two patients were admitted to the hospital with symptoms due to clenbuterol poisoning.     

Defining susceptibility of broiler chicks to colibacillosis.

This study aimed to define the susceptibility of broilers to colibacillosis through quantification of clinical responses and to examine the relationship between susceptibility and growth retardation. A challenge experiment was carried out twice. In each trial, 192 chicks were challenged intratracheally with Escherichia coli (E. coli) at 7 days of age and 160 chicks served as controls. Surviving chicks were euthanized at 14 or 15 days. Parameters measured were: daily mortality, lesion scores, body weight at 1, 4, 7, 10, 12 and 14 or 15 days and feeding behaviour at 6, 11 and 13 days. The results were reproducible, and increasing susceptibility to colibacillosis was defined by four categories: chicks without lesions, chicks with airsacculitis but no systemic lesions, chicks with systemic lesions, and chicks that die. Increasing susceptibility was associated with increasing growth retardation, but growth retardation was not inevitably linked to challenge with E. coli.     

Abnormal EMG and SSEP in a young child with an ependymoma

We report our findings on a case of ependymoma in a one-year-old boy. A partial paresis of the left arm was found but the EEG and BAEP were normal. The EMG showed fibrillations and positive sharp waves in the paretic muscles and the SSEP showed a far field negativity. After removal of the cerebral process all neurophysiologic findings normalized. We discuss a hypothesis for the established clinical neurophysiological findings.     

Pharmacokinetics of piperacillin and tazobactam in critically ill patients with renal failure, treated with continuous veno-venous hemofiltration (CVVH)

Objective: Kinetics of piperacillin (pip), in combination with the beta-lactamase inhibitor tazobactam (taz) have been studied in volunteers and patients in relatively stable conditions. The fixed drug preparation appeared to have ideal pharmacokinetic properties if renal function was normal or slightly impaired, but no data are available for critically ill patients in anuric renal failure. This study should provide such data. Patients, design: We studied the pharmacokinetics in nine patients with multiple organ failure, including anuric renal failure, treated with continuous veno-venous hemofiltration (CVVH). Patients received a standard schedule of 4 g pip and 0.5 g taz administered over 0.5 h intravenously, 8 hourly. During 2 consecutive days, the serum levels of both compounds were determined, and total clearance (CI_T) was calculated from serum concentrations. Results: All nine patients completed day 1, and 8 completed day 2 of the protocol. On day 1, single-dose kinetics showed considerable spread, but pip/taz serum levels followed the pattern as expected, with a pip / taz concentration ratio of 20 : 1. On day 2, however, taz serum concentrations showed a relative increase as compared to pip, resulting in a change in the serum pip/taz concentration ratio to 10 : 1 on day 2. The CI_T of pip was 2.52 ± 1.38 l/h (t ¹/₂ : 5.9 ± 2.9 h), and CI_T of taz 4.44 ± 2.28 l/h (t ¹/₂ : 8.1 ± 3.7 h). The CI_T and t ¹/₂ of pip and taz correlated highly significantly with clearance by CVVH. Despite a higher CI_T, taz has a longer half-life, because of a higher volume of distribution. Conclusion: In CVVH dependent patients, pip/taz fixed drug preparations can be used initially, but the pip dosage should be increased relative to that of taz (or interval-adjusted) to prevent cumulation of taz, as compared to the active antimicrobial agent pip. Received: 19 February 1997 Accepted: 20 May 1997     

Movement-related potentials preceding voluntary movement are modulated by the mode of movement selection

In two experiments movement-related cortical potentials preceding voluntary movement were recorded. In experiment 1, subjects performed four motor tasks involving joystick movements. The four tasks differed in complexity (single vs sequential movements) and in the mode of movement selection, i.e., whether a movement or movement sequence was made in fixed or in self-determined directions. The choice of these tasks was based, firstly, on previous electrophysiological studies suggesting an effect of task-complexity on the amplitude of the readiness potential (RP) and, secondly, on previous positron emission tomography (PET) studies showing that activity of the supplementary motor area (SMA) is influenced by the mode of movement selection. The results show that, for single movements, RP amplitude is higher preceding freely selected movements than preceding movements in a fixed direction. In experiment 2 this effect was replicated using button presses instead of joystick movements. The results converge with PET evidence obtained in similar tasks and establish that the RP is modulated by the mode of movement selection. This modulation is probably related to differential involvement of the SMA.     

B cell epitope specificity in ANCA‐associated vasculitis: does it matter?

Pauci‐immune idiopathic small‐vessel vasculitis is strongly associated with the presence of antineutrophil cytoplasm autoantibodies (ANCA). Antibodies to PR3 predominate in patients with Wegener's granulomatosis; antibodies to myeloperoxidase (MPO) are found more frequently in patients with microscopic polyangiitis. There is increasing in vivo and in vitro evidence for a pathogenic role of ANCA in systemic vasculitis based on associations of ANCA with disease activity. If ANCA are pathogenic, why is the course of disease different from one patient to another? Antibodies can recognize different binding sites (epitopes) on their corresponding antigens. Differences in binding specificity may influence the pathogenic potential of the antibodies. Differences between epitope specificity of ANCA between patients or changes in epitope specificity of ANCA in time in an individual patient may, accordingly, result in differences in disease expression. This review will focus on epitope specificity of autoantibodies in systemic autoimmune diseases and especially on the epitope specificity of PR3– and MPO–ANCA. We will discuss whether PR3–ANCA or MPO–ANCA recognize different epitopes on PR3 and MPO, respectively, and whether the epitopes recognized by ANCA change in parallel with the disease activity of ANCA‐associated vasculitis. Finally, we will speculate if the direct pathogenic role of ANCA can be ascribed to one relapse‐ or disease‐inducing epitope. Characterization of relapse‐ or disease‐inducing epitopes bound by PR3–ANCA and MPO–ANCA is significant for understanding initiation and reactivation of ANCA‐associated vasculitis. Elucidating a disease‐inducing epitope bound by ANCA may lead to the development of epitope‐specific therapeutic strategies.     

The effect of a live vaccine on the horizontal transmission of Mycoplasma gallisepticum.

The effect of a live Mycoplasma gallisepticum vaccine on the horizontal transmission of this Mycoplasma species was quantified in an experimental animal transmission model in specific pathogen free White Layers. Two identical trials were performed, each consisting of two experimental groups and one control group. The experimental groups each consisted of 20 birds 21 weeks of age, which were housed following a pair-wise design. One group was vaccinated twice with a commercially available live attenuated M. gallisepticum vaccine, while the other group was not vaccinated. Each pair of the experimental group consisted of a challenged chicken (10(4) colony-forming units intratracheally) and a susceptible in-contact bird. The control group consisted of 10 twice-vaccinated birds housed in pairs and five individually housed non-vaccinated birds. The infection was monitored by serology, culture and quantitative polymerase chain reaction. The vaccine strain and the challenge strain were distinguished by a specific polymerase chain reaction and by random amplified polymorphic DNA analysis. In both experiments, all non-vaccinated challenged chickens and their in-contact 'partners' became infected with M. gallisepticum. In the vaccinated challenged and corresponding in-contact birds, a total of 19 and 13 chickens, respectively, became infected with M. gallisepticum. Analysis of the M. gallisepticum shedding patterns showed a significant effect of vaccination on the shedding levels of the vaccinated in-contact chickens. Moreover, the Cox Proportional Hazard analysis indicated that the rate of M. gallisepticum transmission from challenged to in-contact birds in the vaccinated group was 0.356 times that of the non-vaccinated group. In addition, the overall estimate of R (the average number of secondary cases infected by one typical infectious case) of the vaccinated group (R = 4.3, 95% confidence interval = 1.6 to 49.9) was significantly lower than that of the non-vaccinated group (R = infinity, 95% confidence interval = 9.9 to infinity). However, the overall estimate of R in the vaccinated group still exceeded 1, which indicates that the effect of the vaccination on the horizontal transmission M. gallisepticum is insufficient to stop its spread under these experimental conditions.