PubMed Health⌕ Search

Biomedical subjects

N Kakitsuba

Publications and source records attributed to N Kakitsuba.

18 recordsLinked to original sources
PubMed1997

Peculiar snoring in patients with multiple system atrophy: its sound source, acoustic characteristics, and diagnostic significance.

It is known that abductor paralysis (AP) of the vocal folds sometimes occurs in patients with multiple system atrophy (MSA), and some of them have sleep apnea and loud snoring during sleep. However, the site of obstruction and the sound source of the snoring are still unknown. We performed fiberscopic examinations under diazepam sedation in 8 MSA patients with AP and analyzed the snoring sound. We found that the peculiar snoring occurred with inspiratory vibration of the vocal folds, and there was no obstruction in this portion. Acoustic analysis showed that the fundamental frequency of vocal fold snoring was 260 to 330 Hz, which is different from that of ordinary soft palate snoring. Recognition of vocal fold snoring is important in the early diagnosis of MSA and sleep-related breathing disorders.

Adult↗
PubMed1996

Articulation after uvulopalatopharyngoplasty.

We performed perceptual and acoustic studies to demonstrate articulation after uvulopalatopharyngoplasty (UPPP) in Japanese patients at 28.6 days (mean) after surgery (range 21-50 days). The results of listening tests showed that there were no significant changes between pre- and postoperative articulation scores for any of 25 monosyllables tested, and there were no significant changes in the timbres of 5 Japanese vowels after UPPP. In the acoustic study of the first and second formant frequencies of the vowels, some formant frequencies had significant changes after UPPP. However, these changes in formants fell within the range of intraindividual variation. In the acoustic study of /ka/ with a palatal plosive /k/, there was no significant change in the voice onset time or F2 transition after UPPP.

Adult↗
PubMed1996

Sleep-related breathing disorders in patients with multiple system atrophy and vocal fold palsy.

We performed sleep studies in eight patients with multiple system atrophy (MSA) and three patients with peripheral bilateral vocal fold palsy (PBVFP) and investigated stenosis of the upper airway tract during sleep in MSA patients with vocal fold palsy. Among the eight MSA patients in this study, five had definite glottic snoring and two others were suspected of having glottic snoring. Of the PBVFP patients, two had glottic snoring. Three of 11 patients died, and two of the three deaths occurred during sleep. Glottic snoring indicated a high degree of negative esophageal pressure. High negative esophageal pressure demonstrates severe narrowing of the upper airway tract. Therefore, glottic snoring should be considered a risk factor for sudden death in sleep. Repeated laryngoscopic examination is useful in evaluating the progressive process of vocal fold palsy while awake, but this examination performed only while awake is not enough to evaluate narrowing of the upper airway during sleep. Sleep studies that include the measurement of esophageal pressure can be very useful in evaluating the severity of narrowing in the upper airway tract. It is suspected that sudden nocturnal death in MSA patients is caused not only by abnormal respiration resulting from impairment of the respiratory center, but also by glottic obstruction caused by sputum or by edema of the vocal folds. We recommend treatment of respiratory disorders when loud laryngeal snoring occurs in patients with MSA, even if they do not complain of dyspnea while awake.

Adult↗
PubMed1996

The value of sleep nasendoscopy in the evaluation of patients with suspected sleep-related breathing disorders.

Fifty patients with sleep-related breathing disorders were tested with nocturnal polysomnography and with nasendoscopic diurnal polysomnography after diazepam administration, and various indices of breathing disorders were examined, and the results obtained in the two sleep studies compared. There were no significant differences between the two sleep studies in either the type of apnoea or the indices of breathing disorder except for the longest duration of apnoea. There was a significant difference in the duration of REM sleep between the two sleep studies, but no significant difference in the duration of each stage of non-REM sleep. We speculate that nasendoscopic diurnal polysomnography with diazepam can be used as a substitute for nocturnal polysomnography in the clinical study of non-REM sleep stage but it is not sufficient in evaluating REM sleep stage, in patients with sleep-related breathing disorders without pathological obesity or abnormal respiratory function.

Diazepam↗
PubMed1996

[Evaluation on rebound effects when the forearm was exposed to cold air].

Cold exposure treatments including cryotherapy have been developed because of many physiological effects, one of which is the vascular hunting reaction called CIVD. In this study, CIVD was determined from the experiments where subject's right forearm was exposed to various air temperatures. The experiments were carefully designed to induce no pain during cold exposure. Three female and three male subjects participated in the experiments. The right forearm and hand of the subject were exposed to control/cold air temperatures of 30 degrees C/-10 degrees C, 15 degrees C/-15 degrees C, 40 degrees C/-20 degrees C and 25 degrees C/-35 degrees C. Blood flow in the middle finger and skin/core temperature at the middle of the forearm and back of the hand were measured simultaneously. Results showed that the exposure to -10 degrees C for 30 min may induce CIVD most effectively without pain as compared to the other given conditions.

Adult↗
PubMed1994

Sleep apnea and sleep-related breathing disorders in patients with craniofacial synostosis.

Seventeen patients with craniofacial synostosis (CFS) have been treated at the Department of Plastic and Reconstructive Surgery at Osaka Medical College during the past 10 years. Six patients were thoroughly evaluated at the Department of Otolaryngology by polysomnography (PSG), cephalometric X-ray and nasopharyngoscopy during sleep. In 4 of the patients PSG showed obstructive sleep apnea syndromes (OSAS). Heavy snoring without apnea and paradoxical respiration were noted in the other 2 patients. Thus, all of the patients had sleep-related breathing disorders (SRBD). It is assumed that the incidence of SRBD in CFS is high. Cephalometric analysis and profilogram showed maxillomandibular hypoplasia in each patient, and it was assumed that the main cause of SRBD in CFS was stenosis of the upper airway tract caused by maxillo-mandibular hypoplasia. Nasopharyngoscopy was performed during sleep in 2 patients with OSAS secondary to CFS. One patient with adenotonsillar hypertrophy had nasopharyngeal obstruction and another patient whose posterior airway space (PAS) on cephalometric radiograph was 3 mm (normal value: 11 mm) had obstruction at the tongue base.

Acrocephalosyndactylia↗
PubMed1992

Development of a new device to measure local heat exchange by evaporation and convection.

According to the principles of heat and mass transfer, the rate of local heat exchange by convection (C) and local heat loss by evaporation (E) can be estimated if temperature and vapor concentration profiles in the boundary layer are measured. In addition, temperature (Ts) and vapor concentration (rho s) at the surface may be predicted from the measured profiles. On this basis, a new device was developed to measure parabolic profiles by incorporating three relative humidity sensors coupled with thermistors into its probe. It has been evaluated from various tests including human experiments. The results showed that the device, with humidity sensors arranged perpendicular to the surface, could estimate C, E, Ts, and rho s in closer agreement with direct measurements when compared with the conventional gradient method. This confirmed that our method had clear advantages over the conventional gradient method under laminar air flow conditions.

Evaluation Studies as Topic↗
PubMed1990

[Evaluation of a semi-closed underwater breathing apparatus, the "eOBA"].

Semi-closed underwater breathing apparatus has commonly been used among military and commercial divers, but never available for recreational divers because of complicated operations, difficulties of maintenance, and expensiveness. Nippon Sanso K.K. has newly deployed a semi-closed circuit underwater breathing apparatus called the "eOBA". It is especially designed for divers to enjoy shallow (max. 5 m) and short (10 min.) dives. This eOBA was evaluated from manned testing based on physiological requirements for the apparatus. Four male and four female subjects participated in the three test trials. Subjects maintained their position at the depths of 2 m and 4 m for 10 min. and e exercised on the underwater ergometer at the depth of 2.4 m. The pressure at the mouthpiece, tidal volume, breathing rate, the inspired O2 level, CO2 level were monitored on breath-by-breath basis. The inspired O2 level ranged from 45% (at exercise) to 60% (at rest) and the inspired CO2 level were kept less than 1.0% in the most cases. The P-V loop indicated relatively little external work of breathing (less than 0.1 kg.m/l) and allowable peak pressures (less than 25cmH2O). Results show that the eOBA meets the standards sufficiently under the test conditions and is a safe apparatus for recreational divers if it is properly used.

Adult↗
PubMed1989

[Changes in transcutaneous tcPO2 during water immersion and its effects on the human body].

Changes in transcutaneous PO2(tcPO2) during water immersions with O2 and N2 bubbling are presented. Three healthy male volunteers underwent water immersions for 30 min. Water temperature was controlled to 36.5 degrees C to minimize any thermal stress. Minute ventilation (Ve), oxygen consumption (VO2), heart rate (HR), respiratory rate (RR), and body temperature (Tb) were continuously monitored throughout exposure. In addition, tcPO2 electrode was mounted on the volar side of the right forearm in the middle part of immersion and tcPO2 and tcPCO2 were then monitored in the water. Blood flow of the right forearm was also measured following tcPO2/tcPCO2 measurements The tcPO2 values during water immersions with O2 bubbling were higher than those with N2 bubbling for given blood flow. Although end-tidal PO2 remained unchanged for any occasion, Ve, VO2, HR, RR during water immersions with O2 bubbling were significantly decreased compared to those with N2 bubbling. Results suggest that cutaneous respiration facilitated by hydration may contribute higher tcPO2 values during water immersions with O2 bubbling and may be somewhat related to systemic changes.

Adult↗
PubMed1989

Effect of peripheral temperature on the formation of venous gas bubbles.

Temperature of the tissue affects the many components involved in the formation of tissue gas phase formation: diffusion, perfusion, and inert gas solubility. Since the effects of perfusion and inert gas solubility may be counteracting in terms of enhancing growth of gas bubbles, the optimal thermal status of divers throughout a dive remains unresolved. To elucidate the role of peripheral body temperature on gas phase formation, four subjects were exposed to a 10 degree and 40 degree C environment for 3 h on two separate occasions, after a no-stop decompression from a 12-h dive to 9.14 m (30 fsw) on air. The 3-hour exposures to either a cold or warm air environment resulted in a significant difference in mean skin temperature (P less than or equal to 0.01) with no alteration in rectal temperature. Total peripheral resistance during the 10 degree C exposure was 13.8 +/- 1.9 mmHg.liter-1.min-1 and significantly higher than that observed during the 40 degree C exposure (10.4 +/- 3.5 mmHg.liter-1.min-1). Gas bubbles in the venous return were monitored with a Doppler ultrasonic transducer placed in the precordial region, both at rest and after a deep knee bend. Venous bubbles were only detected in 1 subject following the warm air exposure, whereas 3 of the 4 subjects developed Doppler-detectable bubbles during the cold air exposure. Although both the cold and warm air exposures (3 h postdecompression) were uneventful, a hot shower taken by the subjects on completion of the cold air exposure (6 h postdecompression) precipitated mild type I symptoms of decompression sickness. These symptoms were not present after a hot shower following the warm air exposure. The present results indicate that despite the assumed greater inert gas solubility of tissues expected during cold air exposure, the decrease in the perfusion may have played a more significant role in the observed levels of detectable venous gas bubbles. Development of type I symptoms following a 12-h saturation, a 3-h cold exposure, and a subsequent hot shower suggests that a rapid rise in peripheral temperature may cause a significant rise in tissue gas tension. This increase in tension does not seem to be sufficiently reduced by increased perfusion to the tissues to prevent bubble formation.

Adult↗
PubMed1988

Dynamic moisture permeation through clothing.

Dynamic moisture permeation through clothing often occurs during thermal transience, causing an imbalance between evaporative heat loss from the skin (Esk) and that from the clothing surface (Ecl). A device was designed to observe Esk and Ecl simultaneously. It consists of two relative humidity sensors coupled with thermistors so that densities of water vapor at two points within the boundary layer can be calculated. The rate of local evaporation is then estimated from Fick's law of diffusion. Local evaporation rates from the skin and clothing surface at the chest, arm, and thigh were measured during exposure to controlled ambient temperatures varying from 20 degrees-40 degrees C. The subjects wore four different types of helicopter pilot suits: Nomex/Neoprene, Goretex, cotton ventile, and Nomex/Insulite. For the Goretex and cotton ventile suits, consisting of relatively permeable and hygroscopic fabrics, a sudden increase in Esk, exponential decay of Esk, and a gradual increase in Ecl were observed. These appear to be associated with, respectively, the onset of sweat secretion, moisture build-up within the clothing, and water gain in the fabric. Thus, the device may be useful for observing dynamic moisture permeation through clothing.

Adult↗
PubMed1987

Heat transfer from the human body in hyperthermic, low gas-velocity environments.

We studied the physics of heat transfer from the human body under conditions of low air velocity (LAV) (less than 0.1 m.s-1). For 1 ATA, we calculated values of the evaporative heat transfer coefficient (he, kcal.m-2.h-1.mm Hg-1) of 5.24 and 5.37 where ambient temperature/relative humidities were 38 degrees C/70% and 35 degrees C/80%, respectively, and ambient velocities of 0.06 m.s-1 in both cases. This is near our newly conceived "minimum he value" of 4.94, significantly greater than the 2.8 and 3.4 values that are calculated using the Lewis relation. We further described an "iso-vapor pressure temperature difference," delta Tp, which transcribes a water vapor pressure difference into a temperature difference, thus allowing use of classical nondimensional analysis to account for the increasing importance of heat loss through evaporation in LAV. Water vapor pressure differences in LAV hypobaric environments will account for increased heat losses since, for example, the minimum value of he doubles from 4.94 to 9.88 at 0.5 ATA.

Adult↗
PubMed1987

Determining the rate of body heat storage by incorporating body composition.

The rate of body heat storage (S) is often used as an index of thermal stress. The traditional approach for determining S assumes that the specific heat (Cp) of all body tissues may be averaged to 0.83 kcal X kg-1 X degrees C-1, irrespective of the actual proportion of different tissues in the body. The present theoretical analysis primarily partitions the body into N compartments. However, this analytical approach involves the difficulty of making an exact evaluation of the mass and temperature of multiple compartments. Therefore, by adopting a two-compartment (core and shell) model, the specific heat capacities, mass fractions, and changes in the temperatures of the two compartments are combined, and S is defined as a function of adiposity (= mass fraction of peripheral tissues). Evaluation of a newly developed equation showed close agreement with observations during a series of cold-water immersion trials, and indicated that the new approach seems to adequately predict S as related to body composition.

Adult↗
PubMed1987

Clothing surface area as related to body volume and clothing microenvironment volume.

The evaluation of clothing surface area becomes important in analyses of heat exchange between the clothed body and its environment. The evidence accumulated in the studies of radiation area has led to the conclusion that the ratio of clothing surface area to body surface area (fcl) may be defined as a function of clothing insulation. However, the effects of clothing fit have been disregarded. Radiation area factors (Ar/AD) were derived from pictures of five subjects wearing four different helicopter pilot suits. While sitting on a seat suspended in the center of a box-shaped frame, photographs were taken of the subjects with a fish-eye lens at 90 equidistant points on the six sides of the frame. The derived Ar/AD of 0.7 +/- 0.18 for the unclothed subjects closely agreed with that reported by Fanger, while it scattered in a relatively wide range for a given suit. The present study proposes a new approach for predicting fcl as related to body volume and the clothing microenvironment volume. The predictions show a good correlation with the values derived from the photographs. It is, therefore, suggested that improvement in the prediction of fcl has been achieved by incorporating clothing fit.

Anthropometry↗
PubMed1984

Influence of blood flow on cutaneous permeability to inert gas.

A thermally regulated Plexiglas chamber was designed for investigation of transcutaneous diffusion of N2 and helium (He) in the human hand. Influence of cutaneous blood flow in this process was studied simultaneously with gas diffusion measurements. Changes in cutaneous blood flow (Q, in ml X min-1 X 100 ml tissue-1) were effected by altering ambient temperature (T) from 20 to 40 degrees C (Q = 0.08 X 100.07T). We found that the rate of inert gas diffusion through human skin, expressed as conductance (G, in ml STPD X h-1 X m-2 X atm-1), increases exponentially as a function of blood flow, and was indistinguishable between He and N2 (G = 21.19 X 100.0124Q). The permeability, diffusion coefficient per unit diffusion distance (D/h, in cm/h), also rose exponentially as a function of blood flow. But permeability for He (D/h = 0.1748 X 100.0203Q) was greater than that for N2 (D/h = 0.1678 X 100.0114Q). As cutaneous blood flow rises, because of increased temperature, the apparent diffusion distance falls linearly for both N2 and He. The change is more prominent for He than for N2 diffusion. Estimated replacement time for the body stores of N2 by transcutaneous diffusion alone was shortened from 26.8 h at 31 degrees C to 15.1 h at 37 degrees C. It is suggested from this study that beneficial results may be derived during decompression procedure 1) by maintaining an appropriate transcutaneous pressure gradient of inert gases, and 2) by elevating ambient temperature.

Capillary Permeability↗