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Biomedical subjects

T Kawazoe

Publications and source records attributed to T Kawazoe.

At least 55 records · Page 3Linked to original sources
PubMed1994

[The effects of fresh gas flow rate on the work of breathing during semi-closed circuit anesthesia].

To evaluate the effects of fresh gas flow rate on the work of breathing during semi-closed circuit anesthesia, we measured respiratory frequency, tidal volume, inspiratory work of breathing, peak inspiratory and expiratory flow rate and fluctuations in airway pressure during breathing with fresh gas flow of 6 l.min-1, 3 l.min-1 and 1.5 l.min-1. There was no significant difference among three flow rates in terms of tidal volume, respiratory frequency, inspiratory work of breathing, peak inspiratory flow rate and fluctuation in airway pressure at inspiration. On the other hand, in the expiratory phase, peak expiratory flow rate was lower and fluctuation in airway pressure at expiration was higher at 6 l.min-1 than those at 3 l.min-1 and 1.5 l.min-1, which may be indicative of increased expiratory work of breathing. The present study shows that low fresh gas flow rate does not increase the inspiratory work of breathing and high fresh gas flow rate may increase the expiratory work of breathing, implying that lowering the fresh gas flow is profitable for the work of breathing during semi-closed circuit anesthesia.

Adult↗
PubMed1993

Deep thermometry of temporomandibular joint and masticatory muscle regions.

A study was designed to measure noninvasively the deep temperature of the temporomandibular joint (TMJ) region and corresponding regions of the masticatory muscles at rest. With a transcutaneous probe, the deep thermometry of the right and left anterior (Ta) and the posterior portion (Tp) of the temporal muscles, the mid-portion of the superficial belly of the masseter muscles (Mm), and the TMJ regions were measured. In 20 normal male subjects, the deep temperature of the Ta region (mean 36.342 degrees C), the Tp region (mean 36.345 degrees C), and the TMJ region (mean 36.06 degrees C) was higher than that of the Mm region (mean 35.897 degrees C) at rest. In addition, no differences in the deep temperature were observed between the right and left Ta, Tp, Mm, and TMJ regions at rest. All of the normal subjects showed differences between the right and left TMJ region of less than 0.3 degrees C. In 10 patients with craniomandibular disorders, however, eight patients showed differences of more than 0.3 degrees C between the asymptomatic and asymptomatic TMJ region. Because of high sensitivity and specificity, the deep thermometry measurements can provide useful non-invasive information.

Adolescent↗
PubMed1993

[The circulatory responses to tracheal intubation using the timing principle].

The circulatory responses to tracheal intubation using timing principle were investigated in 40 adult patients who underwent elective surgery. They were randomly assigned to one of two groups; 1) timing principle group, and 2) SCC group. In timing principle group, vecuronium 0.15 mg.kg-1 was administered. At the onset of clinical muscle weakness, thiopental 5 mg.kg-1 was given promptly. Sixty seconds after thiopental, patients were intubated. In SCC group, thiopental 5 mg.kg-1 was administered, and when patients lost consciousness, SCC 1 mg.kg-1 was given. After fasciculation, patients were intubated. The increases in systemic blood pressure, heart rate and rate pressure product were significantly lower in patients in timing principle group than in those in SCC group. Intubating conditions were almost excellent in both groups, and there were no complications in this study. In timing principle group, intubation was done 60 seconds after thiopental administration, and its timing coincided with the peak cerebral concentration of thiopental. We considered this coincidence was one of the reasons of fewer responses in patients in timing group than in those in SCC group.

Adolescent↗
PubMed1993

[Interaction of midazolam and thiopental in amnestic effect].

Interaction of midazolam and thiopental in amnestic effect was studied in 30 adult patients who underwent elective surgery of lower extremities under epidural or spinal anesthesia in combination with oxygen, nitrous oxide and low concentration of sevoflurane. Combination of midazolam 2.0-3.0 mg (0.041 +/- 0.006 mg.kg-1) and thiopental 3-5 mg.kg-1 produced amnestic effect in 87% of patients. No side effects, such as decrease in O2 saturation, upper airway obstruction, cardiovascular depression and delayed emergence were observed with this small dose of midazolam. Administration of midazolam 2.0-3.0 mg before epidural, or spinal anesthesia in the operating room under observation of anesthesiologists, followed by thiopental 3-5 mg.kg-1, was safe and comfortable to the patients.

Adult↗
PubMed1992

Influences of roxithromycin on cell-mediated immune responses.

We investigated the effects of roxithromycin (RXM), a synthesized macrolide antibiotic on murine cellular immune responses by examining the in vitro proliferative response of lymphocytes, interleukin 1 (IL-1) production and interleukin 2 (IL-2) production. RXM was orally administered to BALB/c mice at a dose of 5 mg/kg once a day for 42 days. Spontaneous blastic activity of lymphocytes prepared from mice administered with RXM for 7 days was higher than those from control mice. The activity peaked at the 14th day, and then decreased gradually to control levels by the 42nd day. Time kinetics of lymphocyte blastogenesis to concanavalin A showed a pattern similar to that observed in spontaneous blastic activity. Oral administration of RXM also influenced cytokine production; short-term (for 14 days) administration of RXM enhanced both IL-1 and IL-2 production but long-term (for 42 days) administration inhibited them.

Animals↗
PubMed1992

Relative humidity, not absolute humidity, is of great importance when using a humidifier with a heating wire.

OBJECTIVES: Since the introduction of a humidifier with a heating wire, we have frequently experienced severe upper airway obstruction from consolidation of secretions, previously unencountered when a humidifier without a heating wire was used. Such problems led to the suspicion that the heating wire incorporated into the breathing circuit of the heated humidifier might be the cause. Therefore, we scheduled an experiment to assess the hypothesis that relative humidity, rather than absolute humidity, is a dominant factor in the case of drying secretions in the upper airway when using such a humidifier. DESIGN: Three clinical case reports and an experiment with a tracheal model. SETTING: Intensive care units at Saitama Medical Center, Saitama Medical School, Saitama, Japan. PATIENTS: Three intubated patients. MEASUREMENTS AND MAIN RESULTS: An experiment with a tracheal model showed that gas with a higher temperature and lower relative humidity (35 degrees C, 48%) deprived the tracheal model of significantly more water (5.9 +/- 0.2 [SD] g) than gas with a lower temperature and higher relative humidity (24 degrees C, 87%) (2.9 +/- 0.4 g; p less than .01), even though the gases contained the same amount of water vapor (19 mg H2O/L) minus the same absolute humidity. CONCLUSIONS: A heated humidifier with a heating wire incorporated into the breathing circuit may be dangerous when only temperature is monitored and controlled. Relative humidity, rather than absolute humidity, is a dominant factor in the case of drying secretions in the upper airway when using such a humidifier.

Aged↗
PubMed1992

[Evaluation of the timing principle with vecuronium].

We evaluated the usefulness of the timing principle with vecuronium in 60 patients who underwent elective surgery, and divided into two groups according to the dose of vecuronium (0.15 and 0.2 mg.kg-1). First, we studied the interval between vecuronium and thiopental administration in 40 patients. The time after vecuronium administration to onset of clinical muscle weakness was 57.6 +/- 7.8 sec in 0.15 mg.kg-1, and 42.2 +/- 2.2 sec in 0.2 mg.kg-1 group. Then, we made and examined the protocol of the timing principle for the rapid tracheal intubation. Induction of anesthesia with 4-5 mg.kg-1 thiopental was done 40 sec after 0.15 mg.kg-1 in 10 patients, and 30 sec after 0.2 mg.kg-1 vecuronium administration in 10 patients. Intubating conditions were almost excellent 70 sec after thiopental administration. In our study, there were no patients who experienced discomfort during induction. We conclude that the timing principle with vecuronium is useful for rapid-sequence tracheal intubation.

Adult↗
PubMed1992

[Evaluation of the timing principle with small priming doses of vecuronium].

The intubating conditions using the timing principle combined with small priming doses of vecuronium were evaluated in forty patients who underwent elective surgery. They were randomly assigned to one of two groups: 1) timing, 2) timing with priming. In timing group, vecuronium 0.15 mg.kg-1 was administered, and at the onset of clinical muscle weakness, thiopental 4-5 mg.kg-1 was given promptly. Sixty seconds after thiopental, patients were intubated. In the timing with priming group, vecuronium 0.005 mg.kg-1 was administered as priming doses. Four minutes later vecuronium 0.15 mg.kg-1 was given. The administration of thiopental and the intubation were done in the same way as in timing group. The time to onset of clinical weakness after the administration of vecuronium 0.15 mg.kg-1 was significantly shorter in the timing with priming group than that in the timing group (46.1 +/- 4.8 vs. 57.6 +/- 7.8, P < 0.01). There were no significant differences in intubating score, T1, TR, onset time, and duration between the two groups. We conclude that the timing principle combined with small priming doses of vecuronium might be safe and useful for rapid tracheal intubation.

Adult↗
PubMed1991

Intraocclusal distance between the anterior teeth in intercuspal position.

We recorded intercuspal occlusal contacts using silicone for 20 subjects with complete dentition maintaining their masseter muscle contraction levels at 10 and 30% of maximum EMG activity. A computer-aided video system was used to read the silicone image and translate the intensity of transmitted light to the thickness corresponding to the distance between opposing teeth. The intraocclusal distance was greater in the anterior than in the posterior teeth. The intraocclusal distance in the canines was intermediate between that in the incisors and posterior teeth. Although these tendencies were the same at the 10 and 30% EMG levels, an increase in the EMG level decreased all the distances.

Adult↗
PubMed1991

Measurement of muscle fiber conduction velocity in the human masseter muscle using the surface EMG cross-correlation technique.

During sustained isometric contraction of the jaw muscles, the surface electromyography (EMG) power spectrum compresses into lower frequencies. This compression has been mainly attributed to the change of the conduction velocity of the action potentials along the muscle fibers. In this study, the muscle fiber conduction velocity of the masseter muscle was measured by using the surface electrode array and the cross-correlation technique. The conduction velocity of the masseter muscle varied from 6.83 to 18.01 m/s among the eight subjects, and slightly increased with the contraction level.

Adult↗
PubMed1990

[The balance of occlusal contacts during intercuspation using T-scan system].

Many methods have been clinically applied for the occlusal analysis in the intercuspal position. However, none of these methods are quantitative. This study described the new software version of the T-Scan system to record and analyze occlusal contact balance in the anterior-posterior and right-left directions. Six time moment statistics and five force moment statistics were calculated in the midsagittal and the incisal axes of the occlusal plane. In the present study, informed consent was obtained from 60 subjects with natural dentitions and from two patients with craniomandibular disorders. In normal subjects, the time moments and the force moments of occlusal contacts were symmetrical about the midsagittal axis of occlusal plane. The location of the center of effort for the antero-posterior occlusal contacts, which was measured from the incisal axis of occlusal plane, was also in the first molar region. However, any of the above mentioned statistics was abnormal in the patients with craniomandibular disorders.

Dental Occlusion↗
PubMed1990

[Deep temperature of the temporomandibular joint region at rest].

This study was made to measure non-invasively the deep temperature of the temporomandibular joint [TMJ] region at rest. The transcutaneous probe making use of zero-heat-flow method was utilized for the deep thermometry. The following results were obtained. 1. In 20 normal male subjects, no differences of the deep temperature were recognized between the right and the left TMJ regions. 2. In 10 patients with temporomandibular disorders, the deep temperature of the symptomatic TMJ side was significantly higher than that of asymptomatic side.

Body Temperature↗
PubMed1990

[Quantification of tenderness of masticatory muscle].

As more dentists diagnose and treat the patient with temporomandibular disorders, muscle palpation has been recognized as a valuable diagnostic method. But this method was depended on sensibility and experience of the operator. The purpose of this study was to establish the quantification of muscle palpation by new pressure pain threshold apparatus. Pressure pain threshold (PPT) was determined by the subject when a ramp force applied to the skin changed from "pressure" to "pain". The subjects for the experiments were 90 normal males, 100 normal females and one patient with temporomandibular disorders. Total of 12 sites, anterior temporal M., posterior temporal M., superficial portion of masseter M. and deep portion of masseter M., were measured. The results obtained were as follows: 1. The females showed lower PPT than the males. 2. No difference of PPT between right and left sides was recognized in normal subject, but the significant difference in the patient. 3. PPT of the normal subjects were significantly higher in the posterior temporal M. than the other sites and lower in the superficial portion of masseter M. than the other sites.

Facial Pain↗
PubMed1990

[Histologic characterization of late asthmatic response in guinea pigs].

We examined lung tissues in a guinea pig model actively sensitized by inhalation of aerosolized ovalbumin (OA) and found reproducible late bronchial responses (LBR) 7 h and 24 h after OA challenge. Light microscopic examination revealed bronchoconstriction, damage to the epithelium, eosinophil infiltration in both the epithelium and subepithelium, retention of mucous in the pulmonary bronchial lumens and a decrease in the mucous content of Periodic Acid-Schiff (PAS) stain positive cells in the bronchial epithelium in LBR. An increase in the number of PAS-stain positive cells of in the bronchial epithelium was also observed in LBR. Electron microscopic examination revealed eosinophil migration around mast cell at 7 hs after OA challenge. Two different mechanisms of degranulation of eosinophil specific granules were observed in LBR. In one mechanism, the granule core changes after its matrix has changed. In the other mechanism, the granules were exocytosed as a whole, accompanied by the cell membrane and densely clumped chromatin, suggesting burst of eosinophil.

Animals↗
PubMed1990

Noninvasive estimation of the location of the end plate in the human masseter muscle using surface electromyograms with an electrode array.

The purpose of this study was to estimate the location of the end plate in the masseter muscle, and to decide the appropriate position of surface electrodes for recording electromyograms (EMG) in humans. The subjects were 16 males who had no signs or symptoms of muscular disease. Identical electrode arrays were placed on the masseter muscles on each side. Each subject was asked to clench in the intercuspal position at various levels of maximum EMG amplitude. Eleven amplified EMGs were monitored simultaneously using a linear electrode array consisting of 12 stainless steel contacts. Various values were observed in different regions of the masseter muscle for the root mean square rectified EMG during brief isometric contraction. The superior region of the muscle had lower values than the inferior. The end-plate zone, which is in the center of the lower half of the masseter muscle, showed a lower amplitude than other regions. The propagation of motor unit action potentials was also observed. It was concluded that, aside from the end-plate zone, a position within the lower half of the muscle was most suitable for recording the surface EMG of the masseter muscle.

Adult↗
PubMed1990

Automatic diagnosis system of tooth mobility for clinical use.

The examination of tooth mobility gives valuable clinical findings on pathological change in the periodontium. An automatic diagnosis system has been developed for the quantitative evaluation of tooth mobility. Tooth mobility was determined from the vibration characteristics of the periodontium and expressed in terms of such objective biomechanical parameters as stiffness and two damping coefficients. These were displayed on a monitor CRT as a triangular figure. This system is composed of a probe, which comprises a vibrator and acceleration transducers, and a data analysis unit using a personal computer. A dentist can measure the tooth mobility without assistance with a foot-switch to trigger the computer operation. The reliability and the operational facility of the system are considered to be sufficient that it may be used in daily clinical practice. Data were collected from healthy and pathological teeth. The tooth mobility of the pathological tooth and the time course of the change in the mechanical parameters after implantation of the tooth were measured by this system. The advantages of this system compared with previous one, which was also developed by the authors, are discussed.

Adult↗
PubMed1990

[Coronary spasm during laryngoplasty].

A 63-yr-old man weighing 56kg was scheduled for pharyngoplasty under general anesthesia. The patient had no history of ischemic heart disease. Preoperative ECG showed incomplete right branch block. We administered thiopental and succinylcholine for intubation. Anesthesia was maintained with enflurane, nitrous oxide, oxygen and pancuronium bromide. Thirty minutes after the start of incision, the patient developed a severe hypotension and ECG revealed ST elevation and complete AV block. We administered ephedrine hydrochloride, phenylephrine hydrochloride and atropine sulfate. The ECG returned to sinus rhythm but ST segment was depressed this time. We considered it due to coronary spasm, so we started continuous intravenous administration of nitroglycerin (0.5 microgram. kg-1. min-1). One hour later, ST segment returned to normal. ECG showed no remarkable changes and no symptoms were seen after the operation. We found it important to suspect coronary spasm when ECG showed PVC-like abnormal waves with ST elevation. We consider that continuous administration of nitroglycerin at a rate of 0.5 microgram. kg-1. min-1 was effective for the treatment of coronary spasm in this case.

Coronary Vasospasm↗