Biomedical subjects
Publications and source records attributed to T Azumi.
Age-related effects on auditory middle latency responses (MLR) were studied in 51 normal subjects. The linear relationship between the amplitude of Na-Pa and Pa-Nb components and aging was observed, although there was no correlation between aging and the latencies of Na, Pa and Nb. The increases in the amplitudes of Na-Pa and Pa-Nb components might reflect the age-related change of auditory responses.
In coronary cineangiography, both X-ray absorption and light scatter in the image intensifier tend to degrade image quality, and so affect the accuracy of densitometric measurement of vessel diameter. To investigate this problem, we compared the accuracy and precision of the densitometric method and the edge detection method in the automated detection of stenosis in both vessel phantom and clinical studies. In the phantom study, the X-ray penetration was varied by altering the thickness of the model, and the change in the measured diameter obtained by each of the two methods was evaluated simultaneously. A difference of 5 mm in the thickness of the model was found to alter significantly (P < 0.01) measurement of the diameter obtained using the densitometric method, but not that obtained by the edge detection method. In the clinical part of the study, the accuracy of each method in the automated detection of coronary stenosis was evaluated. With respect to the detection of stenosis, the level of disagreement between the assessment of the 3 observers and what was detected by densitometry (22.8%) was 2.9 times higher than the disagreement between the observers' assessment and what was detected using the edge detection method (7.9%). When the background density of the coronary cineangiogram along the axis of the vessel was uneven, many vessel segments which had been evaluated as normal when edge-detection was used were evaluated as stenosed when densitometry was used. This study, then, demonstrates that the Lambert-Beer law does not apply in cases where the thickness of the subject varies in different locations along the axis of the same vessel. We therefore conclude that densitometry is not a reliable means of assessing coronary stenosis in such cases, due to veiling-glare and scatter, and recommend that it not be routinely used in the automated detection of coronary arterial stenosis.
Explore the source record for details and available documents.
The effects of cisapride on the gastrointestinal contractile activity and pharmacokinetics of disopyramide were determined in beagle dogs and patients with arrhythmia. In the animal experiments, the gastric motor index was significantly decreased by i.v. administration of disopyramide in a dose-dependent fashion. The peak decrease of the motor index was observed within 5 min after i.v. injection of disopyramide; the motor index then recovered gradually to the level present prior to drug administration. I.v. administration of cisapride (0.5 mg/kg) markedly increased gastrointestinal contractile activity following the decrease induced by disopyramide pretreatment (5 mg/kg, i.v.). In the clinical studies, the gastric emptying test was performed using the acetaminophen method. A significant correlation between plasma concentrations of disopyramide and gastric emptying time has been found (p < 0.001). The combination of disopyramide (100 mg t.i.d.) and cisapride (2.5 mg t.i.d.) significantly increased gastric emptying compared with that induced by disopyramide alone. The peak plasma concentration of disopyramide in association with cisapride oral administration was significantly higher, and the apparent absorption rate constant and lag time of disopyramide were about 2-fold higher and 2-fold shorter, respectively, than for disopyramide alone. Cisapride, acting as a cholinergic agonist, may counteract the anticholinergic effect of disopyramide on gastric motility. As a factor influencing drug absorption, gastric emptying is of importance, as it determines the rate of drug delivery to the small intestine. Therefore, the oral administration of disopyramide with cisapride may be useful for patients with delayed gastric emptying.
The purpose of the present study was to evaluate the similarities and differences in exteroceptive suppression produced by mental nerve stimulation between the masseter and trapezius muscles. Six normal subjects were studied using various intensities of stimulation. Although the duration and degree of exteroceptive suppression were increased with stimulus intensity in the masseter muscle, they did not correlate with stimulus intensity in the trapezius muscle. The latency and duration in the trapezius muscle were almost the same as those in the masseter muscle. The degrees in the masseter muscle were significantly larger than those in the trapezius muscle. Exteroceptive suppression of the trapezius muscle might have a similar mechanism as that of the masseter muscle, but it may be mediated by the separate interneurons. The projection from the trigeminal afferent to the trapezius motoneuron might be smaller than that to the masseter motoneuron.
To accurately diagnose stenotic lesions on coronary cineangiograms, an automatic detection method using computer image processing was developed. We evaluated its accuracy by comparing the results of computer-aided interpretation (CAI) with those obtained independently by 3 observers. Evaluation was performed on 129 segments from 27 arteries visualized on angiograms obtained in 18 patients. The detection rates of stenosis of the 3 observers by pure visual interpretation were 7.0%, 27.9%, and 17.1%, and using CAI 40.0%, 42.6%, and 47.3%. By computer recognition alone, a detection rate of 51.9% was achieved. The agreement by at least 2 observers (consensus) on the sites with lesions was 41.1% while the consensus of computer recognition regarding the sites with lesion was 40.3%. Therefore, our findings indicated that computer recognition of cineangiograms is likely to result in overdetection of lesions. However, all 3 observers detected stenotic lesions better with CAI than with pure visual interpretation. Accordingly, CAI may improve the reliability of cineangiographic diagnosis.
Several peptides derived from the gastrin-predicted preprohormone sequence were isolated from a human gastrinoma by gel permeation, anion exchange, and reverse phase chromatography. The peptides were identified and characterized structurally by a combination of radioimmunoassays, mass spectral analysis, and microsequence analysis. The largest peptide, progastrin-(1-35) (cryptagastrin), extends from the putative processing site for the signal peptidase to the double basic residues adjacent to the amino terminus of gastrin 34. A shorter form of this peptide, progastrin-(6-35) (cryptagastrin-(6-35), was also isolated in smaller amounts. In addition, sulfated and nonsulfated gastrin 17 amides (progastrin-(55-71)) and the glycine-extended nonsulfated gastrin 17 (progastrin-(55-72)) were identified by radioimmunoassay, and their structures were confirmed by mass spectral analysis. Isolation of cryptagastrin indicates that the signal peptide of human preprogastrin contains 21 amino acid residues, and progastrin, therefore, contains 80 amino acids. There is minimal processing of the cryptic peptide preceding the sequence of gastrin 34. An amidated gastrin form larger than gastrin 34 could contain 71 amino acids. No evidence was obtained for processing that would produce gastrins containing more than 34 but less than 71 amino acid residues.
Explore the source record for details and available documents.
Exteroceptive suppression of the masseter and temporalis muscles, produced by electrical stimulation of the mental nerve, was studied in 23 cases of Parkinson's disease (PD) and 20 age-matched control subjects. Two components were usually observed: early (ES1) and late (ES2). ES2 was estimated in this study. The background electromyographic activity prior to the stimulation showed no difference between normal subjects and patients with PD. The latency of suppression in patients with PD was not different from that in normal subjects. The duration and the degree of suppression were lower in patients with PD when compared with the normal subjects. The reduction of exteroceptive suppression might, at least in part, play a role in the failure of motor control of the face in PD.
In 18 normal subjects and 36 patients with chronic headache (3 cluster headache, 18 maigraine and 15 muscle contraction headache), exteroceptive suppression in the temporalis, masseter and trapezius muscles was examined. In the temporalis and masseter muscles, early and late phases (ES1 and ES2) were observed. In the present study, late response (ES2) was examined. Patients with muscle contraction headache showed an obvious decrease of exteroceptive suppression in duration and degree. Patients with common migraine showed slight reduction of exteroceptive suppression in duration and amount, when compared with normal subjects. Patients with classic migraine or cluster headache elicited almost normal exteroceptive suppression. Exteroceptive suppression in the trapezius muscle consisted of one or two suppressive phase(s). Early phase was small and unstable. In the present study, late response with latency of about 45 ms was examined. In the trapezius muscle, migraine and patients with muscle contraction headache elicited the reduction of the exteroceptive suppression in degree. There might be the failure of the inhibitory interneuron mediating the pathway of exteroceptive suppression not only in patients with muscle contraction headache, but also in patients with migraine, especially in patients with common migraine.
We developed a new, cineangiographic method to accurately measure the dynamic changes in the internal diameter of human arteries in vivo. Cine films were digitized at a spatial resolution of 4 microns/pixel, using a line image sensor. The vessel edges, with a Gaussian fit to a unilateral profile curve of the vessel, were determined with the aid of a computer program. We measured contrast-filled cylinder vessel models (2 to 7 mm in diameter) and evaluated precision, accuracy and linearity of the diameter measurement. A pulsatile vessel model of about 3.9 mm in internal diameter was used to examine the reliability of our method for detecting arterial wall motion. If the coefficient of variation of the vessel diameter determined cineangiographically was less than 2.2% we considered the cineangiograms sufficiently accurate to determine the internal vessel diameter and evaluate arterial distensibility.
A case of interstitial pneumonia accompanying SLE (lupus pneumonia) was reported. Shortness of breath in this patient was aggravating very rapidly even during methyl prednisolone pulse therapy, but the patient was relieved from this symptom soon after double filtration plasma exchange was carried out. We concluded that some cases which are resistant to pulse therapy and whose prognosis is very poor might be saved by plasma exchange.
Distensible abnormality of the coronary arteries was evaluated in children with Kawasaki disease. The internal diameter of the left coronary artery (diameter) was measured by cineangiography. Among 38 children with Kawasaki disease, 17 developed aneurysms which later disappeared (disappearance group) and 21 had no aneurysm (no aneurysm group). Eleven children had no history of the disease (control group). The maximal diameter was recognized in systole and the minimal diameter in diastole. The mean distensibility index ([maximal diameter-minimal diameter]/minimal diameter) was 5.7% in the disappearance group, 7.9% in the no aneurysm group, and 11.3% in the control group. There were significant differences among the three groups. We demonstrated that distensibility in the coronary arteries in children with Kawasaki disease decreased and that in the no aneurysm group distensibility ranged between the values in the control group and those in the disappearance group.
To understand the catecholamine kinetics in the heart during hypotension, we simultaneously measured cardiac sympathetic nerve activity (CSNA), concentrations of norepinephrine (NE) and epinephrine (Epi) in arterial and coronary sinus blood, and coronary sinus plasma flow in 11 cats. With hypotension, NE and Epi concentrations in arterial blood increased more than those in coronary sinus blood. The arteriovenous difference between NE and Epi concentrations increased, whereas coronary sinus plasma flow decreased. The net cardiac uptake of NE from coronary arterial blood was not significant (0.826 +/- 0.506 ng/min) under the control condition. With hypotension, it increased significantly to 9.658 +/- 3.182 ng/min (P less than 0.05) in spite of a CSNA increase to 302.0 +/- 30.3% of that during the control condition. The net cardiac uptake of Epi was significant (1.574 +/- 0.542 ng/min) under the control condition, and, with hypotension, it increased significantly to 4.721 +/- 1.049 ng/min (P less than 0.01). We concluded that during hypotension NE was supplied to the heart from sympathetic nerve endings distributing to the heart and also from coronary arterial blood.
Explore the source record for details and available documents.
A case of progressive osteolysis of the mandible that consisted of extensive fibrosis and granulation tissue and contained the occluded inferior alveolar artery and the inferior alveolar nerve is described. Arsenic trioxide was suspected as the possible precipitating cause of the lesion, which started with an abrupt onset of paresthesia of the lower lip following its application to the mandibular second molar for devitalization.
Explore the source record for details and available documents.
A rare case of a metastatic ameloblastoma of the skull in a 29-year-old woman is reported. An ameloblastoma of the left mandible underwent histological malignant transformation following repeated operations and eventually metastasized to the left temporoparietal region of the skull. The skull tumor showed osteolytic change and marked vascularity in roentgenological examinations. It was removed totally. The histological findings were similar to those of the tumor of the left mandible. The route of the metastasis was considered to be via the left external carotid artery.