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Biomedical subjects

T Himi

Publications and source records attributed to T Himi.

At least 109 records · Page 6Linked to original sources
PubMed1988

Immunosuppressive substance in the sera of head and neck cancer patients.

Serum levels of immunosuppressive substance (IS) and immunosuppressive acidic protein (IAP) were studied by single radial immunodiffusion in 108 patients with head and neck cancer. Mean values of serum IS and IAP in patients with head and neck cancers were as follows: laryngeal carcinoma, 955 +/- 447 micrograms/ml (IS), 604 +/- 324 micrograms/ml (IAP); maxillary carcinoma, 896 +/- 384 micrograms/ml (IS), 568 +/- 246 micrograms/ml (IAP); nasopharyngeal carcinoma, 871 +/- 313 micrograms/ml (IS), 673 +/- 395 micrograms/ml (IAP); hypopharyngeal carcinoma, 1034 +/- 495 micrograms/ml (IS), 669 +/- 335 micrograms/ml (IAP). Except for IAP in hypopharyngeal carcinoma, these values were significantly higher than those of controls (IS, P less than 0.01; IAP, P less than 0.05). The overall positive rates of IS and IAP in the patient group were 46% and 37%, respectively. In patients with laryngeal carcinoma the positive rates of serum IS and IAP were found to be elevated as the disease stage advanced. The IS showed a higher positive rate than IAP in the advanced disease stage. Serial studies revealed that all patients who had recurrent disease after the treatment exhibited marked elevation of serum IS levels; in addition, patients with recurrent cancer showed significantly higher IS levels (1507 +/- 464 micrograms/ml) compared to patients who had remained free of disease in the follow-up period (640 +/- 143 micrograms/ml) (P less than 0.001). These data strongly suggests that serum IS and IAP levels are useful parameters for monitoring the disease stage of head and neck cancer patients.

Adolescent↗
PubMed1988

Retinobenzoic acids. 1. Structure-activity relationships of aromatic amides with retinoidal activity.

Two types of aromatic amides, terephthalic monoanilides and (arylcarboxamido)benzoic acids, have been shown to possess potent retinoidal activities and can be classified as retinoids. The structure-activity relationships of these amides are discussed on the basis of differentiation-inducing activity on human promyelocytic leukemia cells HL-60. In generic formula 4 (X = NHCO or CONH), the necessary factors to elicit the retinoidal activities are a medium-sized alkyl group (isopropyl, tert-butyl, etc.) at the meta position and a carboxyl group at the para position of the other benzene ring. The bonding of the amide structure can be reversed, this moiety apparently having the role of locating the two benzene rings at suitable positions with respect to each other. Substitution at the ring position ortho to the amide group or N-methylation of the amide group caused loss of activity, presumably owing to the resultant change of conformation. It is clear that the mutual orientation of the benzylic methyl group(s) and the carboxyl group and their distance apart are essential factors determining the retinoidal activity. Among the synthesized compounds, 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carbamoyl]benz oic acid (Am80) and 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carboxamido] benzoic acid (Am580) were several times more active than retinoic acid in the assay. They are structurally related to retinoic acid, as is clear from the biological activity of the hybrid compounds (M2 and R2).

Amides↗
PubMed1988

Asymmetry of vertical optokinetic nystagmus and afternystagmus.

The sensorimotor mechanism to stabilize the visual field in upright posture is not the same in earth-horizontal plane and vertical plane, because gravity possesses a directionality which is sensed by gravity-receptors. In this communication, asymmetric behavior of the vertical optokinetic nystagmus and afternystagmus is discussed, in conjunction with lesion placements within the peripheral and central neuro-networks (macula sacculi and cerebellar uvula and nodulus) in squirrel monkeys.

Animals↗
PubMed1988

Temporal bone histopathology over 15 years post-stapedectomy.

Twenty-three temporal bones from 14 patients who had undergone stapedectomy more than 15 years (the longest, 28 years) preceding death were studied microscopically. Although a foreign body reaction was still found in the ears with a polyethylene prosthesis, it was seldom found in the ears with a wire or Teflon prosthesis. As the resorption of the incus was not severe, it was suggested that it occurred in the early stage of post-stapedectomy and the structural condition of the incus and prosthesis was stable for a long time (even over 15 years) after stapedectomy. In all ears, the grafts on the oval window continued to be the adequate barrier between the middle ear and inner ear. Even though cupping of the graft membrane was frequently found, it seemed not to disturb the sound conduction. The depth of the cupping was correlated somewhat with the thickness of the graft.

Aged↗
PubMed1987

The role of saccular afferents in vertical optokinetic nystagmus in primates. A study in relation to optokinetic nystagmus in microgravity.

After bilateral sacculectomies, the squirrel monkey's vertical optokinetic nystagmus showed a gain increase of slow-phase down-nystagmus and a gain decrease of the slow-phase up-nystagmus. The nystagmus beating field of the former shifted upward but that of the latter did not change clearly. These results are in general agreement with the findings in man during the recent shuttle flight and indicate the functional linkage of saccular afferents to the vertical optokinetic nystagmus.

Afferent Pathways↗
PubMed1987

[Count rate characteristics and count loss correction of Positologica II: a whole body positron emission tomograph].

This paper describes evaluation and correction of count rate characteristics of POSITOLOGICA II, a multi-slice whole body positron emission tomography system. The present study was performed using three phantoms; a 5 cm inner diameter, water-filled lucite cylinder, a 20 cm inner diameter, water-filled lucite cylinder and a chest phantom. After injection of high activity (about 1.85 GBq (50 mCi] of 13N ammonia into each phantom, rates of true coincidence, random coincidence and single photon detections were measured during decay of the isotope through more than two orders of magnitude of activity. At very high levels of activity, count rate characteristics of the system were saturated and limited to 660 kcps of total coincidence rate, which was the sum of rates in on-time and off-time windows, by the FIFO (first-in first-out) output frequency. Below those levels of activity the relationship between count loss and true coincidence rate was not unique but depended on the phantom configurations, suggesting that count loss correction using the above relationship was inadequate for quantitative study. However, the relationship between count loss and single rate was almost independent of the phantom configurations. Thus in conclusion count loss could be corrected using single rate for POSITOLOGICA II. A practical method of count loss correction was also proposed.

Models, Structural↗
PubMed1987

[Problems related to tracer concentration and wall thickness: pitfalls in positron CT diagnosis].

Positron emission computed tomography (PET) is regarded an excellent technique for quantitative measurements. However, its accuracy is related to the spatial resolution of the system. The relation between myocardial wall thicknesses as measured by X-ray CT or MRI and the radioactivity as measured using PET was studied in 37 patients. 1. In patients with transmural infarction, the infarcted myocardium was imaged as a region of low radioactivity. However, the myocardium usually exhibited wall thinning, so that partial volume effects must be taken into account in evaluating the radioactivity. 2. In the infarcted regions, the regions of the low radioactivity tended to be larger than those of wall thinning. 3. There were cases with the regional low radioactivity without wall thinning in myocardial infarction and in hypertrophic cardiomyopathy. Because patients with myocardial infarction frequently had regional wall thinning, it seems necessary to correct partial volume effects for the infarcted regions which differ from the normal. It was concluded that, to estimate regional myocardial blood flow or metabolism using PET, it is necessary to supplement another morphological diagnostic method to evaluate myocardial wall thickness.

Ammonia↗
PubMed1987

[Dynamic function studies with positron computed tomography: measurements of regional myocardial blood flow in hypertrophic cardiomyopathy].

A major attribute of positron computed tomography (PCT) is its ability to dynamically measure physiologic processes of the heart. However, quantitative data acquisition and analysis are limited by three major problems: bidirectional activity-cross contamination between the myocardium and the blood, the partial volume effect, and the lower temporal resolution of PCT devices. In the present study, we performed serial six-second PCT scans (fast dynamic study) using 13N-ammonia, and evaluated measurements of regional myocardial blood flow. Six patients with hypertrophic cardiomyopathy (HCM) and five normal subjects were observed. 13N ammonia (4.2-13.0 mCi) was intravenously injected as a bolus, and serial six-second PCT scans were initiated at the times of the tracer injections. The results were as follows: 1. Initial passage of the tracer through the right and left sides of the heart were observed with serial six-second images. 2. In patients with HCM, Myocardial 13N activity was determined by assigning a region of interest (ROI) over the myocardium of greater than 25 mm wall thickness as measured by contrast enhanced CT. In these ROIs, corrections for the partial volume effect and spillover of radioactivity from the blood were not necessary. Arterial 13N activity was determined noninvasively by assigning a ROI over the left atrium. 3. The temporal relationships between the arterial input function and myocardial tracer concentrations were demonstrated. Arterial 13N activity was greatest in the second or third frame, and it rapidly declined thereafter. Myocardial 13N activity increased rapidly, reaching a plateau from the sixth to the ninth frame.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Role of otolith endorgans in the genesis of vestibular-visual conflict sickness (pitch) in the squirrel monkey (first report).

This experiment was designed to clarify each vestibular submodality's role in the genesis of vestibular-visual conflict sickness in pitch. We wanted to determine whether the ablation of the macula utriculi and macula sacculi, totally or separately, unilaterally and bilaterally, preserving the semicircular canals intact, could eliminate the conflict emesis in the squirrel monkey model. Observations were carried out over 5 months. In susceptible animals, the difference in conflict sickness scores between the pre- and the postutriculosacculectomy conditions was statistically significant. However, in less susceptible animals, the scores were low from the beginning and the differences were not statistically significant. Unilateral sacculectomy was performed at the smallest otolith endorgan lesion. The conflict sickness scores declined significantly and no emesis occurred. However, at 4.5 months after the operation, animals regained their preoperative scores; thus indicating that the afferents from the remaining endorgans were sufficient to provoke the sickness. This result indicated that functional neural adaptation took place within the equilibrium system. The trial repetition in normal animals and stapedectomized controls did not produce any clear score change.

Animals↗
PubMed1986

Fast dynamic study in cardiac positron CT using 13N-ammonia in man.

Fast dynamic studies with positron computed tomography (PCT) of the heart have been relatively few because of the technical limitations of prevalently used PCT devices. In the present study, we used a high-sensitivity, whole-body multislice PCT device (POSITOLOGICA-II) and performed serial 6-s PCT scans after the intravenous bolus injection of 13N-ammonia in 15 cardiac patients and 5 normal subjects. On the first image (0-6 s), 13N activity was primarily in the right atrium and ventricle. On the third image (12-18 s), it was primarily in the left atrium and ventricle. These blood-pool images permit evaluation of size and configuration of ventricles and atria in cardiac patients and normal subjects. Clearance of 13N activity in the blood pools and lungs occurred primarily during the 1st min. Thereafter, the myocardial images were delineated. In patients with heart failure, delayed clearance of the tracer from the blood pools and lungs was observed. The results indicate that initial passage of the tracer through the heart can be observed with the use of fast dynamic PCT.

Adult↗
PubMed1985

Immune complexes in otitis media with effusion.

The purpose of this study was to clarify the mechanism of the chronicity of otitis media with effusion (OME). The levels of the IgG-immune complexes (IC) in middle ear effusions (MEE) were determined by using anti-C3 solid phase ELISA. The clinical significance of IC in OME was investigated, and the results were as follows: 1) IgG-IC levels in MEE were found to be significantly elevated in patients with OME and positive rates of IgG-IC in MEE were 58.3% in acute cases, 54.5% in subacute cases, and 52.5% in chronic cases. 2) There was no correlation between IgG-IC levels and IgG levels in MEE which were determined by single radial immunodiffusion method. These results suggested that immune complexes formed in the middle ear cavity might play an important role in the prolonged inflammatory process of OME.

Acute Disease↗
PubMed1985

[Positron computed tomography for myocardial uptake of N-13 ammonia in patients with hypertrophic cardiomyopathy: a preliminary study].

In the present study, positron computed tomography (PCT) was used to evaluate the myocardial uptake of N-13 ammonia in patients with hypertrophic cardiomyopathy (HCM). Eight subjects including two normal persons, four patients with HCM, and two with old myocardial infarction (OMI) were selected for the study. N-13 ammonia was administered intravenously as a bolus and, commencing with the tracer injection, serial 30-second PCT scans were performed. The results were summarized as follows: The first scan exhibiting cardiac blood pool images revealed a reduced left ventricular cavity in the HCM subjects. After clearance of N-13 from the cardiopulmonary vasculature, the left ventricular myocardium was clearly visualized and an increased myocardial mass with characteristic morphology was demonstrated in the HCM subjects. Detailed analysis of the time-activity curves of the blood pool and myocardium derived from these serial scan images disclosed two uptake phases in the uptake mode of N-13 ammonia. In the initial phase within three minutes, the myocardial uptake of N-13 was rapid in the normal and OMI subjects, whereas its significant delay was observed in the HCM subjects. This may reflect an abnormal initial extraction of N-13 ammonia in the HCM patients compared with the other subjects. Subsequently, in the second phase, which was characterized by a gradual increase of N-13 in the myocardium, the HCM subjects revealed higher uptake ratios than did the others. This may indicate an increased extraction of metabolites of N-13 ammonia during the second phase. These preliminary results underscore the usefulness of dynamic PCT with N-13 ammonia for the assessment of HCM.

Adult↗
PubMed1982

Upbeating nystagmus resulting from anticonvulsant intoxication. Report of a case.

A rare case of upbeating nystagmus, which occurred under the condition of a loss of visual fixation, due to anticonvulsant intoxication is reported. This patient, a 29 year old male, suffered from grand mal epilepsy for about 12 years, and he had been treated with anticonvulsive drugs. Although a neurological evaluation by a neurosurgeon could suggest the presence of a vague cerebellar sign, neuro-otological evaluation disclosed diverse abnormal findings which clearly demonstrated the presence of dysfunction in the cerebellar system, especially of the verminal and flocculonodular lobe lesion. This may indicate that the anticonvulsive drug affected the vermis and flocculonodular lobe much more than the hemisphere of cerebellum, or that the cerebellar system sign in verminal and flocculonodular lobe lesion and its connection is detected more easily than the hemispheric lesion with the aid of a neuro-otological examination. It was presumed that the upbeating nystagmus in this case was elicited from the lesion of the anterior vermis of the cerebellum and/or its connections. Usefulness and sensitivity of the neuro-otological examination in the field of dysequilibrium of central disorder as well as peripheral vestibular disorder is emphasized.

Adult↗