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Results for “Telemetry”

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At least 1,477 records · Page 82Linked to original sources

PubMed2004

NRT-based versus behavioral-based MAP: a comparison of parameters and speech perception in young children.

The present study was designed to evaluate the effect of neural response telemetry (NRT)-based cochlear implant (CI) programming versus behavioral-based programming on electrical stimulation parameters (MAP) threshold (T) and comfortable (C) levels and speech perception abilities in young children, during the first year of implant use. Ten congenitally deaf children at the age of 12-39 months (mean age: 25.2 months) implanted with the Nucleus 24R(CS) CI participated in the study. The group was randomly divided into two: (1) NRT-based MAP group (n = 5) consisted of children who were programmed using intra-operative NRT measurements; (2) behavioral-based MAP group (n = 5) consisted of children who were programmed using the behavioral responses of the patients. MAP parameters as well as sound-field aided thresholds and speech perception abilities were compared between the two groups at consecutive programming sessions: 1, 3, 6, and 12 months post initial stimulation. Results indicated no significant differences among NRT-based MAPs and behavioral-based MAPs. Although MAP profiles at initial stimulation differed in the apical region, these differences decreased with time. In addition, a gradual increase of T and C levels of NRT-based MAPs as well as those of behavioral-based MAPs was evident until the 1-month time point, thereafter stabilization occurred. Sound-field aided thresholds improved with time for both groups; however, they were found to be significantly better for the NRT-based MAP group. Despite these differences, speech perception abilities were comparable among groups at 12 months post initial stimulation. NRT-based programming was found to be significantly shorter than behavioral-based programming. In conclusion, for this small group of children, our findings support the use of NRT for programming of young children during the initial period after implantation.

Acoustic Stimulation↗

PubMed2006

Physiological responses of skilled players during a competitive wheelchair tennis match.

The purpose of this study was to determine heart rate (HR, b.min(-1)) response during competitive match play of 6 men who were skilled wheelchair (WC) tennis players. Each participant completed an arm crank ergometer test that measured HR via a telemetry device and O2 via open circuit spirometry from rest until fatigue (.V(O2)peak). Each athlete participated in 2 competitive singles matches during which HRs were recorded in 5-second intervals and O2 was estimated using the corresponding HR values recorded during the arm ergometer tests. Data analysis revealed an average playing intensity of 69.4 +/- 8.9% of HRpeak and 49.9 +/-14.5% of .V(O2)peak. In conclusion, it is recommended that skilled adult WC tennis players perform off-court aerobic conditioning as part of their training program, because the intensity of a competitive WC tennis match is sufficiently high enough to stress the cardiovascular system.

Adult↗

PubMed1987

Relationship between body and testis temperatures in the European hedgehog, Erinaceus europaeus, during hibernation and sexual reactivation.

Simultaneous telemetry of the body and testis temperatures of 8 hedgehogs was carried out during hibernation and during sexual reactivation in spring. Between October and January, when the testes were involuted, the body/testis temperature differential was variable, with mean daily testis temperatures up to 1 degrees C warmer than body temperatures. From mid-February onwards, when plasma testosterone approached maximal concentrations, mean testicular temperatures stabilized 1.4 +/- 0.2 degrees C below body temperatures. During spermatogenesis testicular temperature of hedgehogs was significantly lower than body temperature. Over the euthermic body temperature range of 34.7-36.2 degrees C, testicular temperatures varied from 34.0 to 34.9 degrees C. Only at body temperatures over 36.2 degrees C did testicular temperature reach 35 degrees C. During spermatogenesis hedgehog testis temperatures are similar to those of many scrotal mammals.

Animals↗

PubMed2001

The daily pattern of heart rate, body temperature, and locomotor activity in guinea pigs.

We studied the characteristics of the rhythmicity of heart rate (HR), body temperature (BT), and locomotor activity (LA) in conscious and unrestrained guinea pigs using a telemetry system. HR and/or LA in some guinea pigs clearly showed circadian rhythms, but in others there were no significant daily patterns; BT did not show significant daily rhythms. These results suggest that guinea pigs might have different individual characteristics of rhythmicity, and we should, therefore, be careful when using guinea pigs in chrono-biomedical research. We believe that the results of this study may be useful for future biomedical studies using guinea pigs.

Animals↗

PubMed2002

Power spectral analysis of heart rate variability for assessment of diurnal variation of autonomic nervous activity in guinea pigs.

We established characteristics of power spectral analysis of heart rate variability, and assessed the diurnal variations of autonomic nervous function in guinea pigs. For this purpose, an electrocardiogram (ECG) was recorded for 24 hr from conscious and unrestrained guinea pigs using a telemetry system. There were two major spectral components, at low frequency (LF) and high frequency (HF) bands, in the power spectrum of HR variability. On the basis of these data, we defined two frequency bands of interest: LF (0.07-0.7 Hz) and HF (0.7-3.0 Hz). The power of LF was higher than that of HF in the normal guinea pigs. Atropine significantly reduced power at HF. Propranolol also significantly reduced power at LF. Furthermore, the decrease in the parasympathetic mechanism produced by atropine was reflected in a slight increase in the LF/HF ratio. The LF/HF ratio appeared to follow the reductions of sympathetic activity produced by propranolol. Autonomic blockade studies indicated that the HF component reflected parasympathetic activity and the LF/HF ratio seemed to be a convenient index of autonomic balance. Nocturnal patterns, in which the values of heart rate in the dark phase (20:00-06:00) were higher than those in the light phase (06:00-20:00), were observed. However, the HF, LF and the LF/HF ratio showed no daily pattern. These results suggest that the autonomic nervous function in guinea pigs has no clear circadian rhythmicity. Therefore, this information may be useful for future studies concerning the autonomic nervous function in this species.

Animals↗

PubMed2002

The daily pattern of cardiovascular parameters in Kurosawa and Kusanagi-Hypercholesterolemic (KHC) rabbits.

We studied characteristics of the daily pattern of heart rate (HR), blood pressure (BP), body temperature (BT), and locomotor activity (LA) in conscious and unrestrained Kurosawa and Kusanagi-Hypercholesterolemic (KHC) rabbits and age-matched normal Japanese white (JW) rabbits, using a telemetry system. In all JW rabbits, nocturnal patterns were observed in HR, BT and LA. In the 5 months group of KHC rabbits, however, diurnal rhythm was observed in HR, and in the 10 months group of KHC rabbits, it was also shown in LA. The nocturnal pattern was observed only in BT in 10 months KHC rabbits. Mean blood pressure (MBP) in JW and KHC rabbits showed no clear daily pattern. The mean daily values of HR and BT were not altered between the 5 months and 10 months groups in KHC rabbits, although those in JW were lower in the 10 months group than in the 5 months group. Moreover, the daily values of HR and MBP in KHC rabbits tended to be higher than those in the age-matched JW rabbits. The pulse pressure in the 10 months group of KHC rabbits tended to be greater than the 5 months groups of KHC and JW rabbits. Furthermore, short-term variabilities in BP in the 5 months KHC rabbits were significantly lower than those in the other groups. From these results, it is suggested that the cardiovascular function, including the autonomic nervous function is altered with the development of atherosclerosis in KHC rabbits.

Animals↗

PubMed2002

Diurnal variation of heart rate, locomotor activity, and body temperature in interleukin-1 alpha/beta doubly deficient mice.

This study was investigated the roles of interleukin-1 (IL-1) on diurnal rhythms of heart rate (HR), locomotor activity (LA), and body temperature (BT). For this purpose, HR, LA, and BT were recorded from conscious and unrestrained IL-1 alpha/beta doubly deficient (KO) and normal C57BL/6J mice using a telemetry system. These parameters were continuously recorded from just after to 2 weeks after transmitter implantation, because we thought that the surgical stress-induced IL-1 might affect the biobehavioral activities of the animals. At 1 day after implantation, HR and LA in IL-1 alpha/beta KO mice were higher than those in C57BL/6J mice. While BT in IL-1 alpha/beta KO mice was lower than that in C57BL/6J mice. Moreover, diurnal rhythmicity in these parameters after implantation in IL-1 alpha/beta KO mice appeared earlier than in C57BL/6J mice. At 2 weeks after implantation, there were no significant differences in the light- and dark-phase values of each parameter between IL-1 alpha/beta KO and C57BL/6J mice, however, IL-1 alpha/beta KO mice showed clear ultradian rhythmicity. It is thought that a phenotypical difference in biobehavioral activities between IL-1 alpha/beta KO and C57BL/6J mice may reflect IL-1 induced febrile and behavioral responses. These results suggest that IL-1 may play important physiological and pathophysiological roles on biobehavioral activities.

Animals↗

PubMed2002

Diurnal fluctuations of heart rate, body temperature and locomotor activity in the house musk shrew (Suncus murinus).

Diurnal fluctuations of heart rate (HR), body temperature (BT) and locomotor activity (LA) in the unanaesthetized and unrestrained house musk shrew (Suncus murinus) were studied using a telemetry system. Six adult male shrews (Jic:SUN) weighing 60-70 g were used in the present study. They were housed under conditions of 24 C and a 12/12-hr light-dark cycle. HR, BT and LA were recorded over 10 days, following the post-implantation period (10 days or more) of the telemetric transmitter. A clear nocturnal rhythm of LA was shown, while intermittent and short-term LA were shown during the light period. The mean HR was 323.5 +/- 8.8 bpm in the light period and 354.3 +/- 5.2 bpm in the dark period, and the fluctuation of HR showed a nocturnal pattern. A nocturnal pattern was also observed in BT fluctuation, and all animals lowered their body temperature from 35-37 C to approximately 30 C or below, mostly during the light period. The fall of body temperature progressed over 2-3 hr, and then rose to the baseline temperature rapidly within approximately 30 min. While the body temperature fell, HR markedly decreased to approximately 100 bpm. These results suggest that the shrew has unique physiological properties in maintaining metabolic balance which are anticipated to be caused by the dramatic alteration of the autonomic nervous function.

Animals↗

PubMed2002

Ranges of diurnal variation and the pattern of body temperature, blood pressure and heart rate in laboratory beagle dogs.

Ranges in diurnal variation and the patterns of body temperature (T), blood pressure (BP), heart rate (HR) and locomotor activity (LA) in 61 laboratory beagle dogs were analyzed using a telemetry system. Body temperature, BP, HR and LA increased remarkably at feeding time. Locomotor activity increased sporadically during the other periods. Body temperature was maintained at the higher value after feeding but had decreased by 0.2 C by early the next morning. Blood pressure fell to a lower value after feeding but had increased by 2.8% by early the next morning. Heart rate decreased progressively after feeding and was 14.5% lower the next morning. This study determined that in laboratory beagles the ranges of diurnal variation and patterns of T, BP and HR are significantly different from those reported in humans and rodents, and that over 24 hr these physiological changes were associated with their sporadic wake-sleep cycles of the dogs.

Animals↗

PubMed2004

The daily pattern of heart rate, body temperature, locomotor activity, and autonomic nervous activity in congenitally bronchial-hypersensitive (BHS) and bronchial-hyposensitive (BHR) guinea pigs.

We studied the characteristics of the rhythmicity of heart rate (HR), body temperature (BT), locomotor activity (LA) and autonomic nervous activity in bronchial-hypersensitive (BHS) and bronchial-hyposensitive (BHR) guinea pigs. For this purpose, HR, BT, LA, and electrocardiogram (ECG) were recorded from conscious and unrestrained guinea pigs using a telemetry system. Autonomic nervous activity was analyzed by power spectral analysis of heart rate variability. Nocturnal patterns, in which the values in the dark phase (20:00-06:00) were higher than those in the light phase (06:00-20:00), were observed in HR, BT and LA in both strains of guinea pigs. The autonomic nervous activity in BHS guinea pigs showed a daily pattern, although BHR guinea pigs did not show such a rhythmicity. The high frequency (HF) power in BHS guinea pigs was higher than that in BHR guinea pigs throughout the day. Moreover, the low frequency/high frequency (LF/HF) ratio in BHS guinea pigs was lower than that in BHR guinea pigs throughout the day. These results suggest that parasympathetic nervous activity may be predominant in BHS guinea pigs.

Animals↗

PubMed2004

Characteristics of autonomic nervous function in Zucker-fatty rats: investigation by power spectral analysis of heart rate variability.

We investigated the characteristics of autonomic nervous function in Zucker-fatty and Zucker-lean rats. For this purpose, a long-term electrocardiogram (ECG) was recorded from conscious and unrestrained rats using a telemetry system, and the autonomic nervous function was investigated by power spectral analysis of heart rate variability (HRV). Although heart rate (HR) in Zucker-fatty rats was lower than that in Zucker-lean rats throughout 24 h, apparent diurnal variation in HR was observed in both strains and HR during the dark period was significantly higher than that in light period. Diurnal variation in locomotor activity (LA) in Zucker-fatty rats was also observed, but LA was lower than that in Zucker lean rats, especially during the dark period. There were no significant differences, however, in high-frequency (HF) power, low-frequency (LF) power, and the LF/HF ratio between Zucker-fatty and Zucker-lean rats. The circadian rhythm of these parameters was mostly preserved in both strains of rats. Moreover, the effect of autonomic blockades on HRV was nearly the same in Zucker-fatty and Zucker-lean rats. These results suggest that the autonomic nervous function of insulin-resistant Zucker-fatty rats remain normal, from the aspect of power spectral analysis of HRV.

Animals↗

PubMed2004

Effects of psychological stress on autonomic control of heart in rats.

The aim of this study was to examine the effects of psychological stress on autonomic control of the heart in rats. For this purpose, we evoked anxiety-like or fear-like states in rats by means of classical conditioning and examined changes in autonomic nervous activity using an implanted telemetry system and power spectral analysis of heart rate variability. Anxiety-like states resulted in a significant increase in heart rate (HR), low frequency (LF) power, and LF/HF ratio, with no change in high frequency (HF) power. Fear-like states resulted in a significant increase in HR and a significant decrease in HF power with no significant change in both LF power and LF/HF ratio, although LF/HF ratio increased slightly. These results suggest that autonomic balance becomes predominant in sympathetic nervous activity in both anxiety-like and fear-like states. These changes in rats correspond to changes which are relevant to cardiovascular diseases in humans under many kinds of psychological stress. Therefore, the experimental design of this study is a useful experimental model for investigating the effects of psychological stress on autonomic control of the heart in humans.

Animals↗

PubMed2005

Changes in autonomic control of heart associated with classical appetitive conditioning in rats.

The aim of this study was to examine the changes in autonomic control of the heart associated with classical appetitive conditioning in rats. We trained rats to learn that a movement into a test chamber was followed by delivery of reward (contextual conditioning) and performed power spectral analysis of heart rate variability from electrocardiograms recorded using the telemetry system. We investigated the sympathovagal balance of autonomic regulation of the heart in response to not only the conditioned stimulus (the movement into the test chamber), but also the unconditioned stimulus (reward), and compared the results of these two kinds of emotional states; it might be considered that "the reward-expecting state" is evoked by the conditioned stimulus and "the reward-receiving state" is evoked by the unconditioned stimulus in rats. The reward-expecting state resulted in a significant increase in both low frequency (LF) power and high frequency (HF) power with no change in heart rate (HR) and LF/HF ratio, indicating that both sympathetic and parasympathetic activity increased with no change in sympathovagal balance. The reward-receiving state resulted in a significant increase in HR and a significant decrease in LF power, HF power, and LF/HF ratio, indicating that both sympathetic and parasympathetic activity decreased with predominance in the parasympathetic activity. These results suggest that the method performed in our present study might be useful for distinguishing between two different emotional states evoked by classical appetitive conditioning in rats.

Animals↗

PubMedDate not supplied

[Clinical profile of Chagas and non-Chagas' disease patients with cardiac pacemaker].

The aim of this study was to compare Chagas and non-Chagas' disease patients using single or dual-chamber pacemaker in relation to the ejection fraction of the left ventricle, the ventricular stimulation threshold and the occurrence of ventricular arrhythmia. From January, 2001 to November, 2002, 45 Chagas' disease patients and 35 non-Chagas' disease patients, all pacemaker users, were evaluated considering clinical history, echocardiographic study, Holter monitoring and analysis of the pacemaker telemetry data. Chagas' disease patients were significantly younger, but both groups were similar when chest X-Ray variables and right ventricular stimulation threshold were analyzed. Chagas' disease patients had a lower left ventricular ejection fraction and more frequent ventricular arrhythmia during Holter monitoring. A positive correlation between the low ejection fraction of the left ventricle and the intensity of ventricular arrhythmia was observed. In conclusion, among pacemaker user patients, Chagas' disease is related to cardiac markers of worse prognosis.

Aged↗

PubMed2001

Enhancing longevity of pacemakers through reprogramming. Underutilization and cost-effectiveness.

OBJECTIVE: This study was performed to observe the number of pacemakers that had never been reprogrammed after implantation, and the effect of optimised output programming on estimated longevity of pulse generators in patients with pacemaker METHODS: Sixty patients with Teletronics Reflex pacemakers were evaluated in a pacemaker clinic, from the time of the beginning of its activities, in June 1998, until March 1999. Telemetry was performed during the first clinic visit, and we observed how many pulse generators retained nominal output settings of the manufactures indicating the absence of reprogramming until that date. After evaluation of the capture threshold, reprogramming of pacemakers was performed with a safety margin of 2 to 2.5:1, and we compared the estimated longevity based on battery current at the manufacturer's settings with that based on settings achieved after reprogramming. RESULTS: In 95% of the cases, the original programmed setting was never reprogrammed before the patients attended the pacemaker clinic. Reprogramming the pacemaker prolonged estimated pulse generator life by 19.7+/-15.6 months (35.5%). CONCLUSION: The majority of the pacemakers evaluated had never been reprogrammed. Estimated pulse generator longevity can be prolonged significantly, using this simple, safe, efficacious, and cost-effective procedure.

Calibration↗

PubMed2003

Circadian rhythms in blood pressure in free-ranging three-toed sloths (Bradypus variegatus).

Blood pressure (BP) profiles were monitored in nine free-ranging sloths (Bradypus variegatus) by coupling one common carotid artery to a BP telemetry transmitter. Animals moved freely in an isolated and temperature-controlled room (24 degrees C) with 12/12-h artificial light-dark cycles and behaviors were observed during resting, eating and moving. Systolic (SBP) and diastolic (DBP) blood pressures were sampled for 1 min every 15 min for 24 h. BP rhythm over 24 h was analyzed by the cosinor method and the mesor, amplitude, acrophase and percent rhythm were calculated. A total of 764 measurements were made in the light cycle and 721 in the dark cycle. Twenty-four-hour values (mean +/- SD) were obtained for SBP (121 +/- 22 mmHg), DBP (86 +/- 17 mmHg), mean BP (MBP, 98 +/- 18 mmHg) and heart rate (73 +/- 16 bpm). The SBP, DBP and MBP were significantly higher (unpaired Student t-test) during the light period (125 +/- 21, 88 +/- 15 and 100 +/- 17 mmHg, respectively) than during the dark period (120 +/- 21, 85 +/- 17 and 97 +/- 17 mmHg, respectively) and the acrophase occurred between 16:00 and 17:45 h. This circadian variation is similar to that observed in cats, dogs and marmosets. The BP decreased during "behavioral sleep" (MBP down from 110 +/- 19 to 90 +/- 19 mmHg at 21:00 to 8:00 h). Both feeding and moving induced an increase in MBP (96 +/- 17 to 119 +/- 17 mmHg at 17:00 h and 97 +/- 19 to 105 +/- 12 mmHg at 15:00 h, respectively). The results show that conscious sloths present biphasic circadian fluctuations in BP levels, which are higher during the light period and are mainly synchronized with feeding.

Analysis of Variance↗

PubMed2006

A review of digestible microsystems for gastrointestinal tract diagnostic applications.

Present methods for investigation of the GI tract are invasive, distressing for the patient, and give a low diagnostic yield. Wireless, radio telemetry capsules, capable of monitoring physiological changes or visualizing the GI tract are noninvasive and could realize a faster time to diagnoses along with improved treatment of both organic diseases and functional disorders. Consequently, the patient's quality of life would improve. In this paper, early radiotelemetry capsules and the motivating factors for their development are discussed. Following this, prototype and commercially available digestible microsystems making use of microelectronics and microelectromechanical systems are presented. It is shown that these capsules have the potential to combine the functions of their predecessors and furthermore can be used for visualizing the gastrointestinal tract. These systems have the potential to improve diagnostic yield and, in the future, treatment of disease using these capsules should become a reality.

Capsules↗

PubMed2000

Surgical implantation of radiotelemetry transmitters in European badgers (Meles meles).

The suitabilities of two subcutaneous and two intraabdominal surgical approaches were evaluated for implantation of telemetry transmitters in the European badger (Meles meles). Two transmitters, one for heart rate and the other for body temperature, were needed in each badger. Five wild badgers were trapped, housed in an outdoor pen, anesthetized, and surgically implanted with one or two transmitters per procedure. A total of 16 transmitters were implanted, 10 subcutaneously and six intraabdominally, and each badger had up to three procedures performed. Six subcutaneous transmitters were placed over the chest wall and four on the dorsal aspect of the neck. Three intraabdominal transmitters were placed free in the abdomen and three were fixed to the abdominal wall. Eight of the subcutaneous transmitters were later damaged or dislodged, probably by mechanical friction, injuries from fighting, or wound licking. The intraabdominal implantation procedures were easier and faster to perform compared with subcutaneous procedures. Two of the free intraabdominal transmitters became thinly encapsulated, with some omental adhesions. The fixed intraabdominal approach for transmitter implantation is preferable in badgers.

Abdomen↗