Biomedical subjects

H Minamitani

Publications and source records attributed to H Minamitani.

34 records · Page 2Linked to original sources

PubMed1994

Reconstruction of anal function by transposed gracilis muscle with electrical stimulation: rabbit model.

For the reconstruction of anal function for fecally incontinent patients, it could be practicable to transpose the gracilis muscle around the anal canal, with electrical stimulation to maintain contraction. It is necessary to keep continuous tonus, so tetanic contraction or "summation" would be essential for fecal continence, with a stimulation which permits prolonged contraction. Transposition of the gracilis muscle around the rectum was performed in thirteen Japanese white male rabbits. The muscles of the conditioning group (n = 8) were stimulated at 10 Hz for 6 weeks before the procedure. By stimulation at 15 Hz, a low frequency to permit prolonged contraction, the neoanal pressure increased maximally to 134.2 +/- 55.6 cmH2O (mean +/- s.d.) in the conditioning group, and to 115.0 +/- 37.1 cmH2O in the non-conditioning group (n = 5) (N.S.). But, the basal pressure with stimulation rose 82.3 +/- 12.4% (mean +/- s.d.) of the increase in the conditioning group, while that of the non-conditioning group remained at resting pressure (p < 0.001). The conditioning made it possible for the rabbit's gracilis muscle to create anal pressure with a sufficient rise in the basal pressure at a frequency permitting prolonged contraction.

Anal Canal↗

PubMed1993

Microscopic laser Doppler velocimeter measuring blood velocity in single microvessel.

A microscopic laser Doppler velocimeter to measure blood velocity in single microvessels was developed. In order to measure the blood velocity in microvessels correctly, the influence of stray scattered light from vessel wall should be removed. Because it provokes low-frequency spurious components. The spectra of the spurious components overlap with that of Doppler signal and induces considerable error in the result of the blood velocity when the velocity is reduced. The optical configuration of the velocimeter was optimized to eliminate the influence of the stray scattered light. The blood velocity in microvessels in rat mesentery was measured with the microscopic laser Doppler velocimeter and the periodical fluctuation of the velocity was analyzed. Pulsatile velocity fluctuation could be observed even in capillary.

Animals↗

PubMed1993

[Transsubmucosal maxilloethmoid sinus surgery through inferior turbinate (swinging of nasolacrimal duct and inferior turbinate)].

We recently devised a new technique for endonasal surgery, which simplifies maxillary antrotomy and ethmoidectomy, and dilates the middle nasal meatus widely enough to allow easier postoperative observation. Surgery is initiated by an incision similar to the one used for submucosal resection of the inferior turbinate. The bony inferior turbinate is resected, and the nasolacrimal duct is freed from the bone. Subsequently, the maxillary and ethmoidal sinuses are excenterated, with swinging of the membranaceous inferior turbinate and the nasolacrimal duct. Postoperative observation confirmed satisfactory results.

Adolescent↗

PubMed1991

Phosphorus-31 NMR spectra by the linear prediction z-transform method.

The linear prediction z-transform method (LPZAR) was applied to estimate 31P NMR spectra of perfused rat hearts. The spectra obtained by the LPZAR method showed sharper peaks with less noise for phosphate concentrations than those obtained by conventional fast Fourier transform. The LPZAR method provided a better estimation of intracellular phosphate concentrations in short acquisition time experiments in which condition Fourier transform spectra are not suitable for the quantification due to the poor resolution of FFT spectra. Utilizing the LPZAR method, rapid changes in phosphoric metabolites of the heart can be monitored during ischemia followed by reperfusion.

Animals↗

PubMed1990

[Relation between localization of gastric mucosal lesions and microvascular disturbance].

Acute gastric mucosal lesions in the rats were produced by intermittent electrical stimuli to a main trunk of the left gastric artery (LGA), right gastroepiploic artery (RGEA) or a posterior branch of the left gastric artery (PLGA). The image processing analysis was applied to determine the relation between distribution of the lesions and perfusion area of the supplying artery to which electrical stimuli were given. Electrical stimuli of 50 Hz, 5 msec, 100 microA was supplied to the artery for 30 sc three times with 10 sec interval. A series of these stimuli was repeated three times. The mucosal blood flow measured with the laser doppler method in each perfusion area was reduced to less than 35% of the control value during the electrical stimuli for 30 sec. After the repeated electrical stimuli to LGA, 85.8 and 95.4% of the mucosal lesions were found in the mean and maximum perfusion area of LGA, respectively. Electrical stimuli to PLGA caused 84.5% and 95.3 of the lesions in the mean and maximum area of PLGA, respectively. Stimuli to RGEA caused 53.4% and 74.1% of the lesions in the mean and maximum perfusion area of RGEA. In the antrum, electrical stimuli to LGA, PLGA or RGEA produced 0%, 5.4% or 5.0% of the mucosal lesions. It is concluded that the corpus mucosal lesions induced by regional ischemia are distributed in the ischemic area.

Animals↗

PubMed1989

[Effect of sevoflurane on respiratory impedance measured by the forced oscillation method with random noise input].

This study was performed to investigate the effect of sevoflurane, a new inhalation anesthetic, on the respiratory impedance measured by forced oscillation method with random noise input. Random noise (1 to approximately 25Hz) oscillated by a loudspeaker was imposed on the respiratory system of dogs through a tracheostomy and the oscillatory pressure wave and flow wave were monitored at the same point with a pressure transducer and a pneumotachograph. This procedure was repeated during inhalation of 100%-oxygen, 2.0%-then 4.0%-sevoflurane-oxygen mixture, respectively. Impedance was calculated with fast Fourier transform by spectrum analyzer and a personal computer. During inhalation of 4.0%-sevoflurane-oxygen mixture, respiratory impedance especially respiratory resistance decreased at the high frequency area (6to approximately 20Hz), but 2.0%-sevoflurane-oxygen mixture did not cause a significant change of respiratory impedance. This study suggests that inhalation of an anesthetic concentration of sevoflurane produces weak bronchodilation compared with halothane or enflurane.

Anesthetics↗

PubMed1989

[Partitioning and measurement of respiratory impedance into central and peripheral airways with catheter tip type transducer].

In this study, we have examined the availability of catheter tip type transducer for the partitioning of respiratory impedance. Total respiratory resistance and reactance from 1 to 20 Hz determined by forced oscillation method with random noise input in anesthetized dogs were partitioned by catheter tip type transducer into central airway resistance (Rc) and reactance (Xc) as well as peripheral resistance (Rp) and reactance (Xp). Intratracheal acetylcholine (0.1g) increased Rp at the wide frequency range (from about 1 to 20 Hz), although Rc did not change with it. The decreases of Rc at higher frequencies (over 12Hz) were produced by intratracheal salbutamol (10mg), whereas Rp did not change significantly. These results suggest that the predominant site of action of intratracheal acetylcholine and salbutamol is peripheral airway and central airway respectively. We have concluded that the respiratory impedance can be partitioned noninvasively with catheter tip type transducer without pneumothorax and hemorrhage caused with the retrograde catheter. This method can be applied clinically during general anesthesia or in intensive care.

Acetylcholine↗

PubMed1988

New methods for removing saccades in analysis of smooth pursuit eye movement.

New computation methods for removing saccades in analysis of smooth pursuit eye movement characteristics were developed. They have removed saccades more completely than previous methods, and were very effective especially for noisy data recorded by the EOG method. The fully developed method was applicable to eye movement data in tracking of pseudo-random target movement as well as deterministic target movement. Furthermore, the methods were also useful for extracting the number and magnitudes of saccades more precisely.

Electrooculography↗

PubMed1987

Increased lymphocyte transport by lipid absorption in rat mesenteric lymphatics.

The effect of olive oil administration on lymphocyte transport through mesenteric lymphatics was examined to see the possible involvement of nutritional absorption in lymphocyte traffic from the intestinal mucosa. After the olive oil administration to rats, remarkable increase in lymphocyte flux was observed within 2 h in lymph samples collected from rats with lymphatic fistula. The use of a high-speed microscopic video system made it possible to analyze accurately the lymphocyte transport in rapid movement that could not be detected by any of the ordinary video systems. The direct observation of mesenteric collecting lymphatics by this system showed an increment of lymphocyte transport from the intestinal mucosa by lipid absorption in 2 h. The contraction frequency of intestinal collecting lymphatics was also enhanced by olive oil administration. The densitometric analysis on video image was applied to estimate the extent of lipid absorption. The combination of a high-speed video system and the densitometric analysis revealed that the increase in lymphocyte flux occurred before lipid absorption reached its maximum and also demonstrated that the lymphocyte transport returned to control levels under the maximal absorptive condition. The results suggest that the fat absorption could be an important factor influencing the lymphocyte transport in the lymphatic system of intestine.

Absorption↗

PubMed1987