Effect of transcutaneous electrical muscle stimulation and passive cycling movements on blood pressure and removal of urea and phosphate during hemodialysis

BACKGROUND: Intradialytic exercise has been described to improve blood pressure stability and dialysis efficacy. However, comorbid conditions in the dialysis population often preclude the widespread use of active intradialytic exercise. Therefore, we investigated the effect of intradialytic transcutaneous muscle stimulation (TEMS) and passive cycling movements (PCMs) on blood pressure and dialysis efficacy in patients. STUDY DESIGN: Prospective, controlled, randomized, crossover investigation. SETTING ; PARTICIPANTS: Ten patients were randomly allocated to TEMS, PCMs, or no intervention (NI) for 9 consecutive dialysis sessions. INTERVENTION: Participants were studied with NI, PCMs using a motor-driven ergometer, and bilateral TEMS of the leg musculature. Individual dialysis prescriptions were unchanged during the investigation. OUTCOMES ; MEASUREMENTS: The effect of TEMS and PCMs on blood pressure and dialysis efficacy in patients was assessed. RESULTS: Mean blood pressure increased from 121/64 +/- 21/15 mm Hg with NI to 132/69 +/- 21/15 mm Hg (P < 0.001) during sessions with PCMs and 125/66 +/- 22/16 mm Hg (P < 0.05) during sessions with TEMS. Urea and phosphate removal during dialysis were significantly (P < 0.001) greater with TEMS (19.4 +/- 3.7 g/dialysis and 1,197 +/- 265 mg/dialysis) or PCMs (20.1 +/- 3.4 g/dialysis and 1,172 +/- 315 mg/dialysis) than with NI (15.1 +/- 3.9 g/dialysis and 895 +/- 202 mg/dialysis). Body weight, ultrafiltration, Kt/V, and increases in hemoglobin and albumin levels during dialysis did not differ among the NI, PCMs, and TEMS groups. LIMITATIONS: The study design does not allow extension of the findings to prolonged treatment. CONCLUSION: Future studies during longer observation periods will have to prove the persistence of these acute findings. Both TEMS and PCMs deserve future investigations in dialysis patients because they increase intradialytic blood pressure and facilitate urea and phosphate removal when applied short term.

Comparison of mesencephalic free-floating tissue culture grafts and cell suspension grafts in the 6-hydroxydopamine-lesioned rat

Ventral mesencephalon (VM) of fetal rat and human origin grown as free-floating roller-tube (FFRT) cultures can survive subsequent grafting to the adult rat striatum. To further explore the functional efficacy of such grafts, embryonic day 13 ventral mesencephalic tissue was grafted either after 7 days in culture or directly as dissociated cell suspensions, and compared with regard to neuronal survival and ability to normalize rotational behavior in adult rats with unilateral 6-hydroxydopamine (6-OHDA) lesions. Other lesioned rats received injections of cell-free medium and served as controls. The amphetamine-induced rotational behavior of all 6-OHDA-lesioned animals was monitored at various time points from 18 days before transplantation and up to 80 days after transplantation. Tyrosine hydroxylase (TH) immunostaining of the histologically processed brains served to assess the long-term survival of grafted dopaminergic neurons and to correlate that with the behavioral effects. Additional cultures and acutely prepared explants were also fixed and stored for histological investigation in order to estimate the loss of dopaminergic neurons in culture and after transplantation. Similar behavioral improvements in terms of significant reductions in amphetamine-induced rotations were observed in rats grafted with FFRT cultures (127%) and rats grafted with cell suspensions (122%), while control animals showed no normalization of rotational behavior. At 84 days after transplantation, there were similar numbers of TH-immunoreactive (TH-ir) neurons in grafts of cultured tissue (775 +/- 98, mean +/- SEM) and grafts of fresh, dissociated cell suspension (806 +/- 105, mean +/- SEM). Cell counts in fresh explants, 7-day-old cultures, and grafted cultures revealed a 68.2% loss of TH-ir cells 7 days after explantation, with an additional 23.1% loss after grafting, leaving 8.7% of the original number of TH-ir cells in the intracerebral grafts. This is to be compared with a survival rate of 9.1% for the TH-ir cells in the cell-suspension grafts. Immunostaining for the calcium-binding proteins calretinin, calbindin, and parvalbumin showed no differences in the neuronal expression of these proteins between the two graft types. In conclusion, we found comparable dopaminergic cell survival and functional effects of tissue-culture grafts and cell-suspension grafts, which currently is the type of graft most commonly used for experimental and clinical grafting. In this sense the result is promising for the development of an effective in vitro storage of fetal nigral tissue, which at the same time would allow neuroprotective and neurotrophic treatment prior to intracerebral transplantation.

Real-Time Passive Capturing of the GSM Radio

This paper addresses the problem of service development based on GSM handset signaling. The aim is to achieve this goal without the participation of the users, which requires the use of a passive GSM receiver on the uplink. Since no tool for GSM uplink capturing was available, we developed a new method that can synchronize to multiple mobile devices by simply overhearing traffic between them and the network. Our work includes the implementation of modules for signal recovery, message reconstruction and parsing. The method has been validated against a benchmark solution on GSM downlink and independently evaluated on uplink channels. Initial evaluations show up to 99% success rate in message decoding, which is a very promising result. Moreover, we conducted measurements that reveal insights on the impact of signal power on the capturing performance and investigate possible reactive measures.

Direction detection thresholds of passive self-motion in artistic gymnasts

In this study, we compared direction detection thresholds of passive self-motion in the dark between artistic gymnasts and controls. Twenty-four professional female artistic gymnasts (ranging from 7 to 20 years) and age-matched controls were seated on a motion platform and asked to discriminate the direction of angular (yaw, pitch, roll) and linear (leftward–rightward) motion. Gymnasts showed lower thresholds for the linear leftward–rightward motion. Interestingly, there was no difference for the angular motions. These results show that the outstanding self-motion abilities in artistic gymnasts are not related to an overall higher sensitivity in self-motion perception. With respect to vestibular processing, our results suggest that gymnastic expertise is exclusively linked to superior interpretation of otolith signals when no change in canal signals is present. In addition, thresholds were overall lower for the older (14–20 years) than for the younger (7–13 years) participants, indicating the maturation of vestibular sensitivity from childhood to adolescence.

SDR-based Passive Indoor Localization System for GSM

This study deals with indoor positioning using GSM radio, which has the distinct advantage of wide coverage over other wireless technologies. In particular, we focus on passive localization systems that are able to achieve high localization accuracy without any prior knowledge of the indoor environment or the tracking device radio settings. In order to overcome these challenges, newly proposed localization algorithms based on the exploitation of the received signal strength (RSS) are proposed. We explore the effects of non-line-of-sight communication links, opening and closing of doors, and human mobility on RSS measurements and localization accuracy. We have implemented the proposed algorithms on top of software defined radio systems and carried out detailed empirical indoor experiments. The performance results show that the proposed solutions are accurate with average localization errors between 2.4 and 3.2 meters.

Effects of Passive Hydrotherapy WATSU (WaterShiatsu) in the Third Trimester of Pregnancy: Results of a Controlled Pilot Study

Background. WATSU (WaterShiatsu) is a complementary therapeutic treatment method comprising passive stretches and massage techniques administered in 35°C warm water. Pregnant women claim safe methods to reduce pain, stress, and fatigue. Therefore, we conducted a pilot study evaluating the effects of WATSU on pregnancy-related complaints in third trimester pregnant women. Methods. Nine healthy pregnant women at gestational week ≥34 were included in an intervention group (receiving WATSU) and compared to eight women in a passive control group (receiving no treatment). WATSU was performed on days 1 and 4 of the study, accompanied by ultrasound examinations. Outcomes include physiological and psychometric as well as qualitative data. Participants in the control group completed questionnaires only. Results. WATSU was found to significantly lower participants’ levels of stress and pain and to improve their mental health-related quality of life and mood. In comparison to the passive control group, participants in the intervention group reported reduction in perceived stress from day 1 to day 8 (p = 0.036, Cohen’s f = 0.57). Qualitative data indicate that WATSU was appreciated as enjoyable and deeply relaxing. No negative side effects were reported. Conclusion. Our findings support the notion that WATSU yields therapeutic benefits for pregnant women and warrant further research. This study has been registered at ClinicalTrials.gov: NCT01708018.

Steady streaming in a two-dimensional box model of a passive cochlea

Acoustic stimulation of the cochlea leads to a travelling wave in the cochlear fluids and on the basilar membrane (BM). It has long been suspected that this travelling wave leads to a steady streaming flow in the cochlea. Theoretical investigations suggested that the steady streaming might be of physiological relevance. Here, we present a quantitative study of the steady streaming in a computational model of a passive cochlea. The structure of the streaming flow is illustrated and the sources of streaming are closely investigated. We describe a source of streaming which has not been considered in the cochlea by previous authors. This source is also related to a steady axial displacement of the BM which leads to a local stretching of this compliant structure. We present theoretical predictions for the streaming intensity which account for these new phenomena. It is shown that these predictions compare well with our numerical results and that there may be steady streaming velocities of the order of millimetres per second. Our results indicate that steady streaming should be more relevant to low-frequency hearing because the strength of the streaming flow rapidly decreases for higher frequencies.

Axial suspension test to assess pre-operative spinal flexibility in patients with adolescent idiopathic scoliosis.

INTRODUCTION An accurate description of the biomechanical behavior of the spine is crucial for the planning of scoliotic surgical correction as well as for the understanding of degenerative spine disorders. The current clinical assessments of spinal mechanics such as side-bending or fulcrum-bending tests rely on the displacement of the spine observed during motion of the patient. Since these tests focused solely on the spinal kinematics without considering mechanical loads, no quantification of the mechanical flexibility of the spine can be provided. METHODS A spinal suspension test (SST) has been developed to simultaneously monitor the force applied on the spine and the induced vertebral displacements. The system relies on cervical elevation of the patient and orthogonal radiographic images are used to measure the position of the vertebras. The system has been used to quantify the spinal flexibility on five AIS patients. RESULTS Based on the SST, the overall spinal flexibility varied between 0.3 °/Nm for the patient with the stiffer curve and 2 °/Nm for the less rigid curve. A linear correlation was observed between the overall spinal flexibility and the change in Cobb angle. In addition, the segmental flexibility calculated for five segments around the apex was 0.13 ± 0.07 °/Nm, which is similar to intra-operative stiffness measurements previously published. CONCLUSIONS In summary, the SST seems suitable to provide pre-operative information on the complex functional behavior and stiffness of spinal segments under physiological loading conditions. Such tools will become increasingly important in the future due to the ever-increasing complexity of the surgical instrumentation and procedures.