Detection of intraneural needle-placement with multiple frequency bioimpedance monitoring: a novel method.

Electrical impedance measurements have been used to detect intraneural needle placement, but there is still a lack of precision with this method. The purpose of the study was to develop a method for the discrimination of nerve tissue from other tissue types based on multiple frequency impedance measurements. Impedance measurements with 25 different frequencies between 1.26 and 398 kHz were obtained in eight pigs while placing the tip of a stimulation needle within the sciatic nerve and in other tissues. Various impedance variables and measurement frequencies were tested for tissue discrimination. Best tissue discrimination was obtained by using three different impedance parameters with optimal measurement frequencies: Modulus (126 kHz), Phase angle (40 kHz) and the Delta of the phase angle (between 126 and 158 kHz). These variables were combined in a Compound variable C. The area under the curve in a receiver operating characteristic was consecutively increased for the Modulus (78 %), Phase angle (86 %), Delta of the phase angle (94 %), and the Compound variable C (97 %), indicating highest specificity and sensitivity for C. An algorithm based on C was implemented in a real-time feasibility test and used in an additional test animal to demonstrate our new method. Discrimination between nerve tissue and other tissue types was improved by combining several impedance variables at multiple measurement frequencies.

Simultaneous assessment of contact pressure and local electrical coupling index using robotic navigation.

PURPOSE: Contact with cardiac tissue is a determinant of lesion efficacy during atrial fibrillation (AF) ablation. The Sensei®X Robotic Catheter System (Hansen Medical, CA) has been validated for contact force sensing. The electrical coupling index (ECI) from the EnSite Contact™ system (St. Jude Medical, MN) has been validated as an indicator of tissue contact. We aimed at analyzing ECI behavior during radiofrequency (RF) pulses maintaining a stable contact through the robotic navigation contact system. METHODS: In 15 patients (age, 59 ± 12) undergoing AF ablation, pulmonary vein (PV) isolation was guided by the Sensei®X System, employing the Contact™ catheter. RESULTS: During the procedure, we assessed ECI changes associated with adequate contact based on the IntelliSense® force-sensing technology (Hansen Medical, CA. Baseline contact (27 ± 8 g/cm(2)) ECI value was 99 ± 13, whereas ECI values in a noncontact site (0 g/cm(2)) and in a light contact site (1-10 g/cm(2)) were respectively 66 ± 12 and 77 ± 10 (p < 0.0001). Baseline contact ECI values were not different depending on AF presentation (paroxysmal AF, 98 ± 9; persistent AF, 100 ± 9) or on cardiac rhythm (sinus rhythm, 97 ± 7; AF,101 ± 10). In all PVs, ECI was significantly reduced during and after ablation (ECI during RF, 56 ± 15; ECI after RF, 72 ± 16; p < 0.001). A mean reduction of 32.2% during RF delivery and 25.4% immediately after RF discontinuation compared with baseline ECI was observed. CONCLUSIONS: Successful PV isolation is associated with a significant decrease in ECI of at least 20 %. This may be used as a surrogate marker of effective lesion in AF ablation.

[Detection and therapy of respiratory dysfunction by implantable (cardiac) devices]. / Detektion und Therapie respiratorischer Störungen durch implantierbare (kardiale) Devices.

Sleep-disordered breathing (SDB) represents a common comorbidity in cardiac patients. The prevalence of obstructive sleep apnea (OSA) and central sleep apnea (CSA) is very high, particularly in patients with heart rhythm disorders and heart failure (HF). Patients with pacemakers (PM) and implantable defibrillators (ICD) including cardiac resynchronization therapy (CRT) show SDB prevalences up to 75%. However, some modern PM, ICD and CRT devices allow the detection of SDB via transthoracic impedance analysis with high sensitivity compared to polysomnographic (PSG) controls. Thus, this method could be of relevance in screening and monitoring SDB in patients with implantable cardiac devices. Preliminary studies demonstrated the possibility to treat OSA in selected patients by stimulation of the cranial nerves, especially the hypoglossal nerve. However, this requires extensive diagnostics and advanced surgical approaches including many medical disciplines and is not part of this review article. However, unilateral and transvenous stimulation of the phrenic nerve to treat central sleep apnea and Cheyne-Stokes respiration in HF patients in particular can be performed by cardiologists. This article summarizes preliminary data on the results of this promising therapy.

NIR and skin impedance spectroscopic measurements for studying the effect of coffee and alcohol on skin, and dysplastic naevi.

BACKGROUND/PURPOSE: Near infrared and impedance spectroscopy can be used for clinical skin measurements and need to be evaluated for possible confounding factors; (i) are skin conditions of the patient and the subsequent skin measurements influenced by alcohol and/or coffee consumption and (ii) are measurements of dysplastic naevi (DN) reproducible over time and significantly different compared to reference skin. METHODS: Near infrared and skin impedance spectroscopic data were analysed multivariately. In the first study, the skin characteristics of 15 healthy individuals were examined related to body location, gender, individual differences, and consumption of coffee or alcohol. The second study included five patients diagnosed with dysplastic naevi syndrome. Measurements were taken on DN and reference skin over time. RESULTS: In the first study, body location and gender had a major influence on measurement scores. Inter-individual skin characteristics and coffee or alcohol effects on skin characteristics were of minor importance. In the second study, it was shown that DN can be differentiated from reference skin and the measurements are stable over time. CONCLUSIONS: Moderate consumption of alcohol and coffee did not influence the results of the measurements. It is possible to follow, stable or changed, characteristics of DN over time.

Bioimpedance for pain monitoring during cutaneous photodynamic therapy: Preliminary study.

BACKGROUND: Pain is a well-known problem associated with light exposure during topical photodynamic therapy (PDT). Different methods for dealing with the pain have been developed over the past years, ranging from cooling with air or water to nerve blocking. However, the mechanisms responsible for the pain induction have not yet been fully understood. AIM: This study aims to evaluate bioimpedance in situ measurements of human skin as a method to shed light on pain-inducing real-time changes during light exposure during topical PDT. METHODS: Cream containing 20% aminolevulinic acid (ALA) was applied on forearms of ten healthy human volunteers. After 24h incubation, the cream was removed and the spots were exposed to red laser light (636nm, 300mW/cm(2)). During light exposure bioimpedance measurements with a 4-electrode set-up were taken at two frequencies (10Hz and 100kHz). RESULTS: A significant drop in skin impedance at high and low frequencies coincided with onset of pain during light exposure of spots treated with ALA. A similar drop was not observed for controls. CONCLUSIONS: Bioimpedance spectroscopy can provide valuable data for real-time observation of changes in skin, and may contribute to an increased understanding of the mechanisms responsible for induction of pain during topical PDT. Future studies are needed.

The potential of transcranial magnetotherapy in color and rhythm therapy in the rehabilitation of ischemic stroke.

A total of 116 patients with ischemic stroke were studied during the early recovery period. The patients were divided into four groups - three experimental groups and one control group. Of these, 87 patients in the first three groups received transcranial magneto- and/or color and rhythm therapy (TcMT, CRT) along with traditional treatment, while the 29 patients of the control group received basal treatment only. TcMT was performed using a bitemporal method, with a running field regime with a modulation frequency of 1-10 Hz. CRT consisted of an alternating scheme of stimulation of the left and right eyes with green and/or blue light with a period of 2-4 sec and an on time of 1 sec. Each of the three experimental groups (group 1 received TcMT, group 2 received CRT, and group 3 received TcMT + CRT) received two courses of treatment separated by 1.5 months. After treatment, all experimental groups, particularly group 3, showed more marked improvements than the control group. Regression of neurological symptomatology on the Lindmark scale in group 3 was 9.5% greater than that in controls; improvements in impairments to activity and self-care ability on the Barthel scale were greater by 8.8%; memory and intellectual changes were also seen on the MMSE and the Luriya and Schulte tests. Rheography and electroencephalography demonstrated significant improvements in hemodynamics and alpha-rhythm differentiation and a 14.6% reduction in the proportion of patients with dysrhythmia in group 3 compared with the control group. The best result on all measures were obtained in patients given the combination of TcMT and CRT; TcMT had the greater influence on hemodynamics, while CRT had the greater effect on psychoemotional status. Both treatments were well tolerated and produced no side effects.

[Preventive measures with low-intensity laser for workers exposed to physical exertion].

Studies covered 168 personal computer users, 98 jewelry female polishers, 64 assemblers of metallic ship frameworks. Various doses of laser rays in accordance with work conditions appeared effective for improving upper limbs microcirculation. The suggested method is based on effects of low-intensity laser irradiation.

Real-time electrical impedance detection of cellular activities of oral cancer cells.

In this study, the electric cell-substrate impedance sensing (ECIS) system was used to study the cellular activities of oral squamous cell carcinoma (OSCC) cells in a real-time and label-free manner. Various cellular activities, including cell adhesion, spreading, proliferation, and drug-induced apoptosis and inhibition of apoptosis, were monitored. A linear relationship was found between the impedance-based cell index and the cell number in the range of 3500 to 35,000 cells/well. Anti-cancer drug-cisplatin-induced OSCC cell apoptosis at the minimal concentration of 5 microM after 20 h of treatment and followed a linear dose-dependent manner in the concentration range from 10 microM to 25 microM. The inhibition of cisplatin-induced apoptosis by the carcinogen, nicotine, at concentrations from 0.1 microM to 10 microM was monitored. The most significant inhibitory effect of nicotine on cisplatin-induced apoptosis was observed at concentrations of 0.5-1 microM. The results obtained with impedance method correlated well with microscopic imaging analysis of cellular morphology and cell viability analysis. This study demonstrated that the impedance-based method can provide real-time information about the cellular activity of viable cells and detect drug-induced cellular activities much earlier than commonly used cell-based image analysis. This impedance-based method has the potential to provide a useful analytical approach for cancer research.

An 8-channel skin impedance measurement system for acupuncture research.

An 8-channel skin impedance measurement system for acupuncture research has been developed. The underlying model of the skin used is a parallel R & C network. Pulses are used to measure the R and C values. The measurement circuit is time multiplexed across the 8 channels at the rate of 2 measurements per second, leading to a complete set of measurements every 4 seconds. In static tests, the system has been operational for over 2 days of continuous measurements. In preliminary human tests, measurements over 2 hours have been collected per subject.

[Possibilities of transcranial magnetic therapy and color and rhythm therapy in rehabilitation of ischemic stroke].

One hundred and sixteen post-stroke patients were studied in the early rehabilitation period. All patients were divided into 4 groups: 3 main and 1 control groups. Three main groups (87 patients) received transcranial magnetic therapy (TMT) and/or color and rhythm therapy (CRT) along with traditional treatment and the control group (29 patients) received only basic therapy. TMT was conducted using bitemporal technique, running regime with modulation frequency 1-10 Hz. In CRT, the alternating stimulation of the right and left eye with green and/or blue color with a period of 2-4 s and duration of luminescence 1s was applied. Each of 3 main groups received 2 treatment sessions with an interval of 1,5 month (1st - TMT, 2nd - CRT, 3rd - TMT + CRT). After the treatment, the marked positive changes were seen in all main groups, in particular in group 3. The improvement of neurologic symptoms on the B. Lindmark scale was higher by 9,5% in group 3 compared to the control one, on the Barthel index - by 8,8%, on MMSE and A. Luria and Schulte test - by 5,4 and 14,3%, respectively. Rheographic and encephalographic study revealed the significant improvement of hemodynamics and alpha-rhythm differentiation, decrease of patients with dysrhythmia by 14,6% in group 3 as compared to the control group. The best results were seen in the combination of TMT and CRT, TMT exerted a higher effect on the hemodynamics and CRT - on the psychoemotional state. Both therapies were well tolerated and had no side-effects.

[Evaluation of the efficacy of therapeutic physical training in patients with osteochondrosis according to rheoencephalography data].

This paper reports results of clinical and rheoencephalographic examination of 40 middle-age women with cervical osteochondrosis and symptoms of insufficiency of vertebrobasiliar blood circulation. A system of methods for therapeutic physical training has beendeveloped to normalize hemodynamics in the basin of vertebral arteries. The system was tested on 20 patients during a year. It included special physical exercises, massage, and automobilization. The efficiency of therapeutic physical training was evaluated by rheoencephalography. The women involved in the testing reported a marked improvement of the health status. Their rheoencephalograms suggested diminishing of the asymmetry coefficient and beneficial effect of therapeutic physical training on the elastic properties of vertebral arteries. No such changes were documented in a control group of women with osteochondrosis.

[Using of adaptive biocontrolling feedbak in the treatment of irritable bowel syndrome].

In original research are compared results of treatment of irritable bowel syndrome (IBS) by standard technique and treatment with to additional application of the control of a biofeedback. The analysis was carried out on dynamics of clinical symptoms in 1 and 6 months after course of treatment. Research showed improvement of results of treatment IBS in the group with additional treatment of a biofeedback.

Development of acupoints discrimination system using electric properties of acupoints and non-acupoints.

The conventional acupuncture-point stimulus pattern uses direct current (DC) to discriminate acupuncture point and meridian lines, which are fundamental to diagnosis and treatment in Oriental medicine. However, DC is insufficiently reliable in discriminating these acupuncture points and lines. To overcome these problems, the authors extracted optimal parameters (e.g., square-like waveform with a frequency of 3 to approximately 5 kHz) with a single power alternating current (SPAC) stimulus pattern of 1.28V. The SPAC stimulus pattern has little or no effect on cells and the body's physiological state and minimizes polarization and ionization of cells because it uses low voltage and alternating current. The authors developed a new meridian discrimination system that can be used with the SPAC.

An efficient BiCGstab solved impedance method for induced field evaluation with a hyperthermia applicator.

This paper presents a stabilized Bi-conjugate gradient algorithm that can significantly improve the performance of the impedance method, which has been widely applied to model low-frequency field induction phenomena in voxel phantoms. The improved quasi-static impedance method offers remarkable computational advantages in terms of convergence performance and memory consumption over the conventional, stationary iterative method-based algorithm. The scheme has been validated against other numerical/analytical solutions on a lossy, multilayered sphere phantom with an ideal coil loop excitation. To further demonstrate the computational performance and application capability of the developed algorithm, the induced fields inside a whole body human phantom responding to hyperthermia device was evaluated. The simulation results show the numerical accuracy and superior performance of the method.

Production of effervescent tablets Mucomali from polysaccharides of Malva Silvestris L.

The aim of the article was the estimation of efficiency of a method of production of effervescent tablets Mucomali from polysaccharides of Malva Silvestris L sum. The 5% polyethylene glycol solution of polyvinylpyrrolidone was used as connective agent. Experimentally was ascertained good solubility of effervescent tablets (Mucomali), produced from polysaccharide of Malva Silvestris L sum. The pressing power 110 mpa was found optimal for getting effervescent tablets of Mucomali.

[Intravascular laser irradiation of blood in complex treatment of obliterating atherosclerosis of the lower extremity vessels in elderly and senile patients].

The authors describe comparative results of treatment of 60 elderly and senile patients with obliterating atherosclerosis of the lower extremity vessels. In 50 patients treatment with traditional medicines was combined with intravascular laser irradiation of blood, 10 patients were treated with traditional medicines only. The data obtained by questionnaires concerning the patients' state, expert judgment of doctors in charge of the profile department, indices of instrumental examinations of regional hemodynamics (rheovasography of the lower extremity vessels), data of laboratory investigations of morphofunctional state of erythrocytes and hemorheology showed that laser irradiation of blood gave better results of treatment. Its therapeutic effect persisted during 3 months in most patients.

An exploratory study of the relationship between the midday-midnight law and electrical conduction properties of corresponding acupuncture points.

The midday-midnight law is a well-known empirical law in Oriental medicine stating that the circadian rhythm of internal organs influences their paired organs according to the time of day. However, there has been little research to test the purported relationship between the time of day and organ function. The purpose of this preliminary study was to investigate whether the midday-midnight law applies to the meridian activity and the electrical conduction properties of the acupuncture points. We used the digital readout instrument (MERIDIAN) to measure electrical conduction properties at 12 acupuncture points corresponding to the 12 meridians at four times: 12:00, 14:00, 22:00, and 24:00 hours. There were no significant differences in the electrical current values measured at the four times in any meridian. However, the mean current values of 12 acupuncture points changed significantly over time (P < 0.0001). The mean current values were significantly higher at 14:00 (P < 0.001), 22:00, and 24:00 hours (P < 0.001) than at 12:00 hours. The highest current value occurred at 22:00 hours and was significantly higher than 24:00 hours (P < 0.05). Although these do not conclusively support the traditional midday-midnight theory, our data suggest the existence of some type of daily variability in electrical current.

[Potentialities of reflexotherapy in complex treatment of hypotonic states]. / Vozmozhnosti refleksoterapii v kompleksnom lechenii gipotonicheskikh sostoianii.

Methods of reflexotherapy in complex treatment of hypotonic state have significant advantage before traditional medicamentous therapy. Patients with hypotonic conditions which received traditional treatment are exposed to the greater risk in development of various forms cerebrovascular pathologies.