Development of a Core Body Thermometer Applicable for High-Temperature Environment Based on the Zero-Heat-Flux Method.

Monitoring core body temperature (CBT) allows observation of heat stress and thermal comfort in various environments. By introducing a Peltier element, we improved the zero-heat-flux core body thermometer for hot environments. In this study, we performed a theoretical analysis, designed a prototype probe, and evaluated its performance through simulator experiments with human subjects. The finite element analysis shows that our design can reduce the influence of external temperature variations by as much as 1%. In the simulator experiment, the prototype probe could measure deep temperatures within an error of less than 0.1 °C, regardless of outside temperature change. In the ergometer experiment with four subjects, the average difference between the prototype probe and a commercial zero-heat-flux probe was +0.1 °C, with a 95% LOA of -0.23 °C to +0.21 °C. In the dome sauna test, the results measured in six of the seven subjects exhibited the same trend as the reference temperature. These results show that the newly developed probe with the Peltier module can measure CBT accurately, even when the ambient temperature is higher than CBT up to 42 °C.

A Detailed Protocol for Perspiration Monitoring Using a Novel, Small, Wireless Device.

Perspiration monitoring can be utilized for the detection of certain diseases, such as thermoregulation and mental disorders, particularly when the patients are unaware of such disorders or are having difficulty expressing their symptoms. Until now, several devices for perspiration monitoring have been developed; however, such devices tend to have a relatively large exterior, considerable power consumption, and/or less sensitivity. Recently, we developed a small, wireless device for perspiration monitoring. The device consists of a temperature/relative humidity (T/RH) sensor, battery-driven small data logger, and silica gel as a desiccant in a small cylindrical exterior. The T/RH sensor is placed between the detection windows (through which the water vapor from the skin enters) and the silica gel. The underlying principle of the perspiration monitoring device is based on Fick's law of diffusion, which means that water vapor flux from the skin to the silica gel (i.e. transepidermal water loss and perspiration) can be captured by change in humidity at the T/RH sensor. In addition, a baseline subtraction method was adopted to distinguish perspiration and transepidermal water loss. As shown in the previous report, the developed device can monitor the perspiration at any sites of the body in an easy, wireless manner. However, detailed methods of how to use the device have not been disclosed yet. In this article, therefore, we would like to show the point-by-point tutorials of how to use the device for perspiration monitoring, by showing the sympathetic activity test with the sympathetic skin response monitoring as an example.

Development of a small wireless device for perspiration monitoring.

A small and wireless device that can capture the temporal pattern of perspiration by a novel structure of water vapor collection combined with reusable desiccant has been developed. The novel device consists of a small cylindrical case with a temperature/relative humidity sensor, battery-driven data logger, and silica gel (desiccant). Water vapor of perspiration was detected by the change in relative humidity and then adsorbed by silica gel, allowing continuous recording of perspiration within a closed and wireless chamber, which has not been previously achieved. By comparative experiments using the commercially-available perspiration monitoring device, the developed device could measure perspiration as efficiently as the conventional one, with a normalized cross coefficient of 0.738 with 6 s delay and the interclass correlation coefficient [ICC(2, 1)] of 0.84. These results imply a good agreement between the conventional and developed devices, and thus suggest the applicability of the developed device for perspiration monitoring.

The nature of sleep in 10 bedridden elderly patients with disorders of consciousness in a Japanese hospital.

No previous study has satisfactorily clarified the nature of sleep in elderly bedridden people with disorders of consciousness (DOC). The objective of the present study was to clarify the sleep states of 10 elderly bedridden patients with DOC in a Japanese hospital to facilitate provision of evidence-based nursing care and appropriate adjustment of patients' environments. Nocturnal polysomnography recordings were analyzed according to the standard scoring criteria, and the patients' sleep stages and quality were investigated. Of the 10 patients, 9 showed slow wave sleep (SWS), 4 showed very high values for sleep efficiency (96-100%), and in 3 of these patients, the percentage of SWS was ≥ 20%. Furthermore, three of these four patients had 200 or more changes in sleep stage. Although the mechanism is unknown, the amount of SWS combined with the value of sleep efficiency suggests that the quality of sleep is poor in elderly bedridden patients with DOC. Further study is needed to determine better indicators of good sleep in this population.

Development of a novel pulse wave velocity measurement system: using dual piezoelectric elements.

The aim of this study is to develop a painless system of measuring the brachial-ankle arterial pulse wave velocity (baPWV) without compression cuffs. The PWV reflects the compliance of the artery and is measured for the early diagnosis of arteriosclerotic vascular diseases. However, the conventional baPWV system, which measures four cuff pressures simultaneously, easily causes circulation block and tightening pain at the extremities. In addition, approximately 15 min are required to stabilise the blood pressure for re-examination. Therefore, we developed a novel baPWV measurement system using dual piezoelectric sensor elements. The principle of this high-sensitivity pressure pulse detection system is based on adding the two in-phase outputs from the coaxially arranged dual piezoelectric sensor. As our system facilitates the measurement of the baPWV by detecting the pulsation of an artery using sensors fixed on the skin where the pulse is palpable, it does not cause pain and reduces examination time. The coefficients of correlation between the baPWV values obtained from the conventional and present methods were 0.93 (right side) and 0.90 (left side). The results suggest that our system can be used to measure the baPWV without pressure cuffs as accurately as the conventional method.

Characterization of ultradian and circadian rhythms of core body temperature based on wavelet analysis.

This study was motivated by the needs of precise characterization for the ultradian and circadian rhythmicity of human core body temperature (CBT). The CBT data, two-whole-days' data of two female bed-ridden old aged suffering from cerebral infarction sequelae, was detrended to eliminate the long-term components with periods longer than two days and normalized at first. It was then analyzed by the stationary wavelets transform (SWT) to get the time-frequency information. In the step of SWT, symlet 6 was used, and the approximation waveforms in the 5th, 6th and 7th levels were used to reveal the targeted rhythmicity. The results of the SWT show that SWT can faithfully reveal the time-frequency information of feature elements (peaks and troughs) of waveforms and rhythmicity can be characterized by analyzing temporal information of feature elements.

Improvement of the dual-heat-flux method for deep body temperature measurement based on a finite element model.

Based on finite element method, this study was dedicated to improve the performance of the newly proposed dual-heat-flux method (DHF) for noninvasive deep body temperature (DBT) measurement. This study focused mainly on the dimensions, e.g., the height and radius, of the probe of DHF to improve its performance, in terms of the measurement depth beneath the skin. This paper was also engaged in confirmation of the improved probe's performance on a physiological significant temperature range, 35 to 40 °C. The results showed that a probe with lower in height and larger in radius would have better performance. It suggests that we should reduce the height of the probe to half of the original and keep the radius unchanged for a better performance.

Jaw-movement smoothness during empty chewing and gum chewing.

A major goal of motor coordination is the production of a smooth movement. Jerk-cost, which is an inverse measure of movement smoothness, has been evaluated during gum chewing in previous studies. However, the effect of the gum bolus is still unclear. The aims of this study were to compare the jerk-cost values of normal gum chewing with those of empty chewing. Thirteen subjects undertook, empty chewing, then chewing of gum, and then a second empty chewing. Jerk-cost was calculated from an accelerometer attached to the skin of the mentum. There was a significantly higher smoothness (i.e. lower jerk-cost, P < 0.05) during the opening and second-half closing phases in empty chewing compared with gum chewing. There were no significant differences in jerk-costs (i.e. opening or closing) between the first and the second empty-chewing sequences. These results suggest that the influence of the mechanical effects of tooth contact on jerk-cost is not restricted just to the occlusal phase of chewing, but rather the effect influences the entire opening and closing phases of chewing.

Characterization of maternal body movement during sleep before and after parturition.

The purpose of this study was to characterize the different features of body movements for females before and after parturition. Body movement signal was measured by a piezoelectric sensor board which was deployed on the abdominal position beneath a mattress during sleep to monitor pressure changes around abdominal area. Body movement epochs were detected by an innovative algorithm based on Hilbert transform. Data were collected from two healthy pregnant females during sleep for 7 weeks before parturition and 6 weeks after parturition. The pressure signal was used to determine the duration and time interval of maternal movements. Characteristics of the detected body movements before and after parturition were investigated through their proportion. The results showed that before and after parturition, the body movement which features as 0~1 min in interval and 0~6 sec in duration has significant difference statistically. It is considered that these differences are highly correlated with the prenatal activities.

Performance assessment on different measurement positions for monitoring HR/RR during sleep.

This study aims to investigate the measurement performance on different sensor deployment and to determine the optimal position for monitoring heart rate (HR) and respiration rate (RR) during sleep. Five identical sensor boards were deployed on different positions simultaneously during sleep to detect changes of applied pressure due to heart beating and breathing. One board was set beneath the pillow; the other four boards were set under the mattress aligning with the head, back, hip and calf, respectively. Data were collected from five healthy subjects during a 2-hour's nap individually. Detection performance was evaluated by sensitivity and positive predictivity. The results showed that nearly all of the positions could be used to detect heart rate; both sensitivity and positive predictivity were over 85% among five persons. All of the positions could be used to detect respiration rate except for calf. The highest performance of sensitivity and positive predictivity in respiration rate detection could be found in the hip position, which reached as high as 99%. The optimal position with overall best performance for HR and RR measurement is considered in the hip.

Osteoblast activity in the goldfish scale responds sensitively to mechanical stress.

The adaptive response of bone to mechanical loading in teleosts is not well understood. We recently developed a new assay system using teleost scales, which consists of osteoblasts, osteoclasts, and bone matrix protein. In this system, alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) were used as markers of osteoblasts and osteoclasts, respectively. Using this assay system, we examined the effects of mechanical loading on ALP and TRAP activity in goldfish scales. ALP activity in the scales was significantly elevated (p<0.01) by ultrasound stimuli (1 MHz, 50% duty factor, 0.5 Hz pulse repetition frequency, 60 mW/cm(2) [I(SATA)] and 6 min) after both 18 h and 24h of incubation while TRAP activity remained unchanged. In addition, mRNA expression of both insulin-like growth factor-I (IGF-I) and estrogen receptors (ER) increased significantly, as did ALP activity. After the goldfish had been swimming for 3 days (speed: 2 body lengths/second, duration: 3h/day), the scales' ALP activity increased significantly (p<0.01) but TRAP activity did not change. These in vitro and in vivo results strongly suggest that osteoblasts in the goldfish scale respond sensitively to mechanical stress and may be important in promoting bone formation.

Long-term monitoring of heart rate, respiration rhythm, and body movement during sleep based upon a network.

A method for accurately recording heart rate (HR), respiration rhythm (RR), and body movement (BM) during sleep using a network-based system is proposed in this article. Its application to the long-term monitoring of HR, RR, and BM during sleep was examined. HR, RR, and BM were detected by pressure variations corresponding to changes in the heartbeat and respiratory motion, which were measured by a sensor unit placed beneath a pillow during sleep under completely unconstrained conditions. The pressure signals were digitized and transmitted to a remote database server using transmission control protocol (TCP)/Internet protocol (IP) via a netbox. In the server, the data were processed to obtain HR, RR, and BM. The overall performance of the system was examined using data collected over a 13-month period from a female subject. Besides the long-term profiles of HR, RR, and the periods during which the HR and RR were undetectable owing to BMs during sleep, the average frequency of BM in a day varied from 4.4 to 22.4/h, and the mean frequency over 332 nights was 8.3/h with a standard deviation of 2.2/h. Periodic biorhythms can also be assessed using the profiles of the average HR and certain frequency-domain parameters of HR variability. The rhythmic property of these profiles was confirmed to coincide with the subject's menstrual cycle. The results of this 13-month trial operation show that this system can be installed in the home environment; used to monitor HR, RR, and BM during sleep; and analyze various physiological rhythms in humans over prolonged periods.

Development of a new method for the noninvasive measurement of deep body temperature without a heater.

The conventional zero-heat-flow thermometer, which measures the deep body temperature from the skin surface, is widely used at present. However, this thermometer requires considerable electricity to power the electric heater that compensates for heat loss from the probe; thus, AC power is indispensable for its use. Therefore, this conventional thermometer is inconvenient for unconstrained monitoring. We have developed a new dual-heat-flux method that can measure the deep body temperature from the skin surface without a heater. Our method is convenient for unconstrained and long-term measurement because the instrument is driven by a battery and its design promotes energy conservation. Its probe consists of dual-heat-flow channels with different thermal resistances, and each heat-flow-channel has a pair of IC sensors attached on its top and bottom. The average deep body temperature measurements taken using both the dual-heat-flux and then the zero-heat-flow thermometers from the foreheads of 17 healthy subjects were 37.08 degrees C and 37.02 degrees C, respectively. In addition, the correlation coefficient between the values obtained by the 2 methods was 0.970 (p<0.001). These results show that our method can be used for monitoring the deep body temperature as accurately as the conventional method, and it overcomes the disadvantage of the necessity of AC power supply.

Unconstrained monitoring of long-term heart and breath rates during sleep.

An unconstrained method for the long-term monitoring of heart and breath rates during sleep is proposed. The system includes a sensor unit and a web-based network module. The sensor unit is set beneath a pillow to pick up the pressure variations from the head induced by inhalation/exhalation movements and heart pulsation during sleep. The measured pressure signal was digitized and transferred to a remote database server via the network module. A wavelet-based algorithm was employed to detect the heart and breath rates, as well as body movement, during sleep. The overall system was utilized for a total six-month trial operation delivered to a female subject. The profiles of the heart and breath rates on a beat-by-beat and daily basis were obtained. Movements during sleep were also estimated. The results show that the daily average percentage of undetectable periods (UPs) during 881.6 sleep hours over a 180 day period was 17.2%. A total of 89.2% of sleep hours had a UP of not more than 25%. The profile of the heart rate revealed a periodic property that corresponded to the female monthly menstrual cycle. Our system shows promise as a long-term unconstrained monitor for heart and breath rates, and for other physiological parameters related to the quality of sleep and the regularity of the menstrual cycle.

Automatic home care system for monitoring HR/RR during sleep.

This paper described an automatic home care system for monitoring HR/RR during sleep. Pressure signal is measured with a completely unconstrained pressure sensor beneath a pillow; then the signal is digitalized and the data are transmitted to a remote server using TCP/IP via a netbox. The data are processed and analyzed with a wavelet-based algorithm to obtain the heart rate and respiration rhythm during sleep. Through analyzing 180 days' data obtained from a female subject, it was found that this system can be used for daily monitoring heart rate and respiration rhythm during sleep and evaluating the quality of sleep at home.

Real-time monitoring of respiration rhythm and pulse rate during sleep.

A noninvasive and unconstrained real-time method to detect the respiration rhythm and pulse rate during sleep is presented. By employing the a trous algorithm of the wavelet transformation (WT), the respiration rhythm and pulse rate can be monitored in real-time from a pressure signal acquired with a pressure sensor placed under a pillow. The waveform for respiration rhythm detection is derived from the 26 scale approximation, while that for pulse rate detection is synthesized by combining the 2(4) and 2(5) scale details. To minimize the latency in data processing and realize the highest real-time performance, the respiration rhythm and pulse rate are estimated by using waveforms directly derived from the WT approximation and detail components without the reconstruction procedure. This method is evaluated with data collected from 13 healthy subjects. By comparing with detections from finger photoelectric plethysmograms used for pulse rate detection, the sensitivity and positive predictivity were 99.17% and 98.53%, respectively. Similarly, for respiration rhythm, compared with detections from nasal thermistor signals, results were 95.63% and 95.42%, respectively. This study suggests that the proposed method is promising to be used in a respiration rhythm and pulse rate monitor for real-time monitoring of sleep-related diseases during sleep.

Intraocular pressure lowering effect of brinzolamide 1.0% as adjunctive therapy to latanoprost 0.005% in patients with open angle glaucoma or ocular hypertension: an uncontrolled, open-label study.

PURPOSE: A prospective study was conducted to evaluate the intraocular pressure (IOP) lowering effect of brinzolamide 1.0% ophthalmic suspension as an adjunctive therapy with latanoprost 0.005% ophthalmic solution in patients with open angle glaucoma or ocular hypertension. PATIENTS AND METHODS: Fourteen patients with open angle glaucoma (OAG) or ocular hypertension (OH) who had been using latanoprost 0.005% for more than 6 months were initiated on adjunctive brinzolamide therapy. The IOP values at 1 month, 2 months, and 3 months were compared with those measured immediately before adding brinzolamide to the regimen (baseline). The incidence of adverse events such as conjunctival hyperemia and corneal epithelial defect were also examined. RESULTS: The baseline IOP was 21.1 +/- 4.8 mmHg (mean +/- standard deviation). After 1 month, 2 months, and 3 months of therapy IOP was 16.9 +/- 4.5 mmHg, 16.6 +/- 4.0 mmHg, and 15.9 +/- 3.1 mmHg, respectively, showing significant reductions in IOP at all the measuring time-points during the study compared with the baseline value (p < 0.01). Conjunctival hyperemia developed in one patient after 1 month and in another after 2 months; however, both were mild, and therapy was continued. Corneal epithelium defect was observed in 3 patients. One of them had mild defect before brinzolamide was added to the regimen. Increase of eye discharge was seen in one patient. No serious side effects were otherwise observed. CONCLUSION: The addition of brinzolamide to a latanoprost 0.005% regimen may further lower intraocular pressure in patients with open angle glaucoma or ocular hypertension.

Radiotelemetry recording of electroencephalogram in piglets during rest.

A wireless recording system was developed to study the electroencephalogram (EEG) in unrestrained, male Landrace piglets. Under general anesthesia, ball-tipped silver/silver chloride electrodes for EEG recording were implanted onto the dura matter of the parietal and frontal cortex of the piglets. A pair of miniature preamplifiers and transmitters was then mounted on the surface of the skull. To examine whether other bioelectrical activities interfere with the EEG measurements, an electrocardiogram (ECG) or electromyogram (EMG) of the neck was simultaneously recorded with the EEG. Next, wire electrodes for recording movement of the eyelid were implanted with EEG electrodes, and EEG and eyelid movements were simultaneously measured. Power spectral analysis using a Fast Fourier Transformation (FFT) algorithm indicates that EEG was successfully recorded in unrestrained piglets, at rest, during the daytime in the absence of interference from ECG, EMG or eyelid movements. These data indicate the feasibility of using our radiotelemetry system for measurement of EEG under these conditions.

Accurate determination of respiratory rhythm and pulse rate using an under-pillow sensor based on wavelet transformation.

A real-time noninvasive and unconstrained method is proposed to determine the respiratory rhythm and pulse rate with an under-pillow sensor during sleep. The sensor is composed of two fluid-filled polyvinyl tubes set in parallel and sandwiched between two acrylic plates. One end of each tube is hermetically sealed, and the other end is connected to one of two pressure sensors. Inner pressure in each tube therefore changes in accordance with respiratory motion and cardiac beating. By employing the á trous algorithm of wavelet transformation (WT), the respiratory and cardiac cycle can be discriminated from the pressure waveforms. The respiratory rhythm was obtained from the WT 26> scale approximation, and the pulse rate from the sum of WT 24and 25scale details without WT reconstruction after soft-threshold denoising. The algorithm's latency can be set to be minimal and the respiratory rhythm and pulse rate were estimated directly from the extracted respiration and pulse waveforms, respectively. This method has been tested with a total of about 25 h data collected from 13 subjects. By comparing the detection results with those of reference data, the average pulse rate detection sensitivity and positive predictivity were 99.17% and 98.53%, and the respiratory rhythm detection sensitivity and positive predictivity were 95.63% and 95.42%.

A novel stereotaxic approach to the hypothalamus for the use of push-pull perfusion cannula in Holstein calves.

To determine secretory patterns of growth hormone-releasing hormone (GHRH) and somatostatin (SS) and their roles in the regulation of growth hormone (GH) secretion, a method for collecting hypothalamic perfusates, a push-pull perfusion method was developed in calves. With the use of the stereotaxic apparatus for cattle, a cannula was implanted into the hypothalamus of four male calves based upon cerebral ventriculography. Push-pull perfusates were collected at 10 min intervals for 6h and GHRH and SS concentrations in perfusates and plasma GH concentration were determined by EIAs and RIA, respectively. A cannula was implanted into the hypothalamus based on the image of the third ventricle and maintained for 1 month. GHRH and SS showed pulsatile secretion and the pulses for GHRH and SS were irregular in conscious animals. Neither GHRH nor SS secretion had a clear relationship with GH secretion. In the present study, we thus (1) established a stereotaxic technique for approaching the hypothalamus using cerebral ventriculography for calves, and (2) demonstrated that GHRH and SS secretion were pulsatile but not closely related to GH profile in conscious calves. The technique is useful for the study of the functions of the hypothalamus in the control of pituitary hormones in cattle.