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Biomedical subjects

M Ohyama

Publications and source records attributed to M Ohyama.

At least 109 records · Page 6Linked to original sources
PubMed1994

[Clinical evaluation of asymptomatic sinus disease detected by MRI].

The detection of lesions of the paranasal sinuses as incidental findings during magnetic resonance imaging of patients suspected of intracranial disease who have no nasal symptoms has been far more common than we expected. The present study was performed on 325 patients a mean age of 60.7 years. Medical histories were taken whether they had any nasal symptoms or not. Asymptomatic sinus disease was present in 41.6% of the 257 patients who had no nasal symptoms, and 9.7% of the patients had either marked mucosal thickening, excessive fluid or polyps in the maxillary sinuses. Although the mean age of these patients was comparatively high, we can infer that 1 in 10 have relatively severe sinus lesions. Mucociliary transport time was measured using the saccharin method in 15 patients who had sinus disease but no nasal symptoms. The mean transport time was 15.6 minutes and within normal limits. Routine ENT examination revealed no lesions in the nasal cavity of any of the subjects. We classified the patients with asymptomatic sinus disease into two groups; group A: patients with sinus disease associated with some nasal manifestations but who do not complain about them, group B: patients who have sinus disease but do not have any nasal problems. Group B represents genuine asymptomatic sinus disease in the narrow sense. Most asymptomatic patients in this study appeared to belong to group B. They had some sinus disease, but because their mucociliary function in their nasal cavity was normal, they did not have any nasal symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Magnetic resonance spectroscopy of naso-sinus tumors].

Magnetic Resonance Spectroscopy (MRS) has been developed as a new application of nuclear magnetic resonance. By means of MRS, internal chemical information can be non-invasively measured. In this study, the 31P MRS of naso-sinus tumors was measured and evaluated. The peaks of 31P MRS, such as Adenosine tri-phosphate (ATP), Creatine phosphate (PCr), Phosphodiester (PME), Inorganic phosphate (Pi), and Phosphomonoester (PME) can be identified. Phosphomonoesters (PME) are precursors of membrane phospholipids. Phosphodiesters (PDE) are metabolites of phospholipids. Compared with benign tumors, the 31P MRS of malignant tumors shows a higher PME peak and lower PDE and PCr peaks. These results indicate that malignant tumors are characterized by chemical changes in membrane metabolism.

Adenosine Triphosphate↗
PubMed1994

Localized aerosol hyperthermia in patients with nasal allergy.

A double-blind study was performed to evaluate the efficacy, the safety and the usefulness of localized aerosol hyperthermia (LAH) in 57 patients with nasal allergy. We used two localized aerosol hyperthermia devices, the equipment (AH) with an insufflated aerosol of 43 degrees C and a placebo device (PH) with aerosol of 32 degrees C. In the evaluation of clinical efficacy, efficacy rates were 46.4% in AH and 3.7% in PH during 2 weeks, respectively, and 53.3% in AH and 7.7% in PH during 4 weeks, respectively. There was a significant difference (p < 0.01) between the two treatment groups. The usefulness rates were 63.3% in AH and 7.4% in PH for patients with nasal allergy, showing a statistically significant difference (p < 0.01). No patients dropped out of the study due to adverse effects. These results suggest that the LAH is a very useful instrument for the treatment of nasal allergy.

Aerosols↗
PubMed1994

The mechanical behavior and morphological structure of callus in experimental callotasis.

Experimental callotasis was made in rabbit femurs. In order to compare mechanical behaviors and morphological structure of callus in callotasis, mechanical tests and histological examination were performed. Twenty Japanese white male rabbits were used. The right femurs were osteotomized at the level of the midshaft with a rotary cutter and fixed with a mini-model external fixator. After a 5-day waiting period, bone lengthening was started at the rate of 0.25 mm two times a day. Animals were divided into four groups. Group 1 and Group 2 were continual distraction group, Group 3 and Group 4 discontinued distraction group. The viscoelastic property was demonstrated in continual distraction group irrespective of distraction period, we thought the central undifferentiated connective tissue in callus was mainly responsible for the mechanical behavior. On the other hand, in discontinued distraction group, viscoelastic property shifted to elastic property corresponding to the rest period, we thought this change of mechanical behavior was histologically owing to the replacement of undifferentiated connective tissue by cartilage and the partial union of bone in callus.

Animals↗
PubMed1993

Behavioral and histological changes after repeated brief cerebral ischemia by carotid artery occlusion in gerbils.

The effects of repeated brief episodes of cerebral ischemia on passive avoidance learning and hippocampal neuronal degeneration were investigated in gerbils. Latency of step-through was shortened for the entire 7-day period when gerbils were trained at day 3 after 3 episodes of carotid artery occlusion for 2 min each at 60-min intervals. In addition, latency of passive avoidance was shortened for 63 days when gerbils were retrained at 14 days after occlusion. Severe neuronal degeneration in the CA1 regions of the hippocampus was observed 4 and 17 days after occlusion. A close correlation was seen between latency in the passive avoidance response and neurological degeneration of the hippocampal CA1 region. This fact was strongly supported by the results of another experiment that 1 2-min occlusion with almost no neuronal degeneration did not affect learning behavior while 3 1-min occlusions showed neuronal death and impairment of learning behavior of a moderate degree 4 days after occlusion. These results suggest that this gerbil model with carotid artery occlusion is useful for the quantitative measurement of functional changes in the chronic phase of repeated cerebral ischemia.

Animals↗
PubMed1993

Degeneration of human respiratory cell ciliary beat in monolayer cell cultures.

The degeneration of ciliary beat of human respiratory cells was studied in monolayer cell cultures by using a differential interference microscope equipped with a high speed video system. This method for studying ciliary beat in cell cultures on collagen-coated cover glasses is quite advantageous, because it allows for detailed study of all parts of ciliary function and not just ciliary beat frequency (CBF). In the present study both CBF and ciliary beat amplitude (CBA) were found to decrease continuously from the 1st day after plating but the wave form of ciliary beat did not change. Cultures with high cell density provided better preservation of normal ciliary beat for a longer period. In contrast, ciliary beat degenerated quickly in cultures with low cell density. CBF and CBA in cell cultures less than 5 days after plating were always high, supporting use of these cultures for studies of normal ciliary motility.

Cell Movement↗
PubMed1993

Chondrosarcoma of the hyoid bone.

Chondrosarcoma of the head and neck is relatively rare. We report the sixth case known to us in which the chondrosarcoma had originated in the hyoid bone. The patient, a 66-year-old man, underwent surgery. The resected tumour was a 5 cm encapsulated lesion composed of lobulated, firm, gray-white tissue. Histologically it showed mature chondrocytes without capsular invasion. There was high cellularity and a few binucleated chondrocytes. Although the tumour grade was prognostic significance, our literature review of the five other cases suggests that the location of the primary lesion and the adequacy of its resection to be more important. Our patient continues to do well 15 months post-operatively. However, long-term follow-up is essential as recurrences have been reported even after eight or 10 years.

Aged↗
PubMed1993

Effects of spiradoline mesylate, a selective kappa-opioid-receptor agonist, on the central dopamine system with relation to mouse locomotor activity and analgesia.

Neurochemical and behavioral investigations were made to assess the role of central dopaminergic systems in mouse locomotor activity and analgesia by spiradoline mesylate. Analgesic activities of the kappa-opioid-receptor agonists spiradoline and U-50488H were not altered by haloperidol or L-dopa, whereas morphine analgesia was enhanced by haloperidol but attenuated by L-dopa. Spiradoline decreased spontaneous locomotor activity in mice and inhibited methamphetamine- or morphine-induced locomotor activity. In contrast, morphine given alone increased locomotor activity and enhanced methamphetamine-induced locomotor activity. In a neurochemical study, spiradoline decreased the amounts of dopamine metabolites in the striatum, but did not alter them in the brainstem and cerebral cortex. Morphine increased the dopamine metabolite contents in all three brain regions tested. These results suggest that inhibition of the dopaminergic pathway in the brain by spiradoline may be involved in its suppression of locomotor activity, but not in its analgesia; whereas, stimulation of the dopaminergic pathway by morphine seems to function in both behaviors: enhancement of locomotor activity and inhibition of analgesia.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1993

Effect of exogenous ATP on ciliary beat of human ciliated cells studied with differential interference microscope equipped with high speed video.

To study the detailed effects of exogenous adenosine triphosphate (ATP) on ciliary function, we used the differential interference microscope equipped with high speed video and evaluated ciliated cells from the human sinus mucosa in monolayer culture. With this system it was possible to evaluate all parts of ciliary motility with a minimum of interference from the mucous membrane, secretory cells and the autonomic nervous system. The best direct ciliostimulative effect of exogenous ATP on ciliary beat frequency (CBF) and ciliary beat amplitude (CBA) was observed at concentrations of ATP ranging from 10(-5) M to 10(-3) M. Exogenous ATP appeared to normalize the slightly damaged ciliary motility in groups with an initial CBF of 14 Hz or higher. When the CBF was less than 14 Hz, ATP produced an increase in CBF greater than 40%, an increase in CBA greater than 30%, but these did not reach the normal level in 5 min. The biggest increases: 59.9% in CBF and 40.7% in CBA were seen in the group with an initial CBF less than 9 Hz. In the cells with a low initial CBF and unsynchronized motility exogenous ATP increased the synchrony of ciliary movement together with an increase in CBF and CBA.

Adenosine Triphosphate↗
PubMed1993

[Gas ventilation through middle ear mucosa].

The possible effects of gas ventilation via the middle ear mucosa on middle ear pressure changes with N2O inhalation were studied. Sixty-seven ears without otologic problems were selected from among cases undergoing ENT surgery under general anesthesia. Anesthesia was induced by isoflurane or sevoflurane, and inhalation with a gas mixture of 21/min O2 and 31/min N2O was started under controlled respiration via endotracheal tube. Middle ear pressure was measured each minute with tympanometry just before and during N2O inhalation. Changes in pressure were plotted against time on an X-Y plotter, and the rate of middle ear pressure change and pressure change in 10 minutes were calculated. The following results were obtained; 1. In all cases, the middle ear pressure rose with N2O inhalation. However, the same concentration of N2O created different middle ear pressure changes in different individuals varying from 1.6 mmH2O to 107.8 mmH2O per minute. 2. The rate of middle ear pressure elevation tended to be greater in younger subjects, especially in children aged 4 to 7. 3. There was a negative correlation between the middle ear pressure change and pneumatization of the middle ear. 4. Sex, pulmonary function, and the N2O expiratory flow concentration did not contribute to the variability in the rate of the middle ear pressure elevation.

Acoustic Impedance Tests↗
PubMed1993

[Changes in regional cerebral blood flow during auditory cognitive tasks--a PET activation study with odd-ball paradigm].

In order to investigate the relation between auditory cognitive function and regional brain activation, we measured the changes in the regional cerebral blood flow (CBF) using positron emission tomography (PET) during the "odd-ball" paradigm in ten normal healthy volunteers. The subject underwent 3 tasks, twice for each, while the evoked potential was recorded. In these tasks, the auditory stimulus was a series of pure tones delivered every 1.5 sec binaurally at 75 dB from the earphones. Task A: the stimulus was a series of tones with 1000 Hz only, and the subject was instructed to only hear. Task B: the stimulus was a series of tones with 1000 Hz only, and the subject was instructed to push the button on detecting a tone. Task C: the stimulus was a series of pure tones delivered every 1.5 sec binaurally at 75 dB with a frequency of 1000 Hz (non-target) in 80% and 2000 Hz (target) in 20% at random, and the subject was instructed to push the button on detecting a target tone. The event related potential (P300) was observed in task C (Pz: 334.3 +/- 19.6 msec). At each task, the CBF was measured using PET with i.v. injection of 1.5 GBq of O-15 water. The changes in CBF associated with auditory cognition was evaluated by the difference between the CBF images in task C and task B. Localized increase was observed in the anterior cingulate cortex (in all subjects), the bilateral associate auditory cortex, the prefrontal cortex and the parietal cortex. The latter three areas had a large individual variation in the location of foci.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Central monoaminergic mechanisms in mice and analgesic activity of spiradoline mesylate, a selective kappa-opioid receptor agonist.

We assessed the roles of brain monoaminergic systems in the analgesic action of spiradoline, a novel kappa-opioid agonist, behaviorally and biochemically by using noradrenaline (NE) and serotonin (5-HT) uptake inhibitors. Analgesic activity was evaluated by measuring latency time in the mouse tail-pinch test. Spiradoline at intramuscular doses of 0.3 mg/kg or more elicited a significant analgesic effect and the metabolism of both NE and 5-HT was significantly increased in brainstem and cortex. Pretreatment of the mice with imipramine, desipramine or clomipramine caused marked potentiation of spiradoline analgesia, whereas reserpine and phenoxybenzamine inhibited it. Morphine analgesia was enhanced by clomipramine but not by imipramine, desipramine or phenoxybenzamine. These results suggest that excitation of noradrenergic and serotonergic pathways in the brain appears to be involved in spiradoline analgesia, and that, as regards tail-pinch nociception, the kappa-opioid agonist acts on the noradrenergic pathway more potently than morphine.

Analgesics↗
PubMed1992

Effect of phosphoenolpyruvate on metabolic and morphological recovery of red cells after prolonged liquid storage and subsequent freezing in glycerol medium.

The present study was designed to determine the effects of (i) phosphoenolpyruvate (PEP) treatment of red blood cells (RBCs) previously cold stored for a prolonged period in a liquid medium and (ii) the freezing of these treated cells in glycerol. RBCs stored for 21 days at 4 degrees C were incubated for 30 min at 37 degrees C with rejuvenant solution containing 50 mM PEP, 60 mM mannitol, 30 mM sodium chloride, 25 mM glucose, and 1 mM adenine, pH 6.0, and then frozen at -80 degrees C for 4 weeks. Red cell recovery as frozen and thawed red cells (FTRCs) after deglycerolization was increased to 80 +/- 4% compared to 43 +/- 9% in units without rejuvenation; the percentage of PEP-treated FTRCs was similar to the percentage of FTRCs recovered from fresh RBCs within 5 days after donation. Incubation of RBCs with PEP solution restored ATP and 2,3-DPG to levels seen in fresh RBCs, and also facilitated transformation of crenated RBCs to discocytes. These results indicate that maximum recovery of viable RBCs can be attained when FTRCs are processed from cells stored in the frozen state after they had been rejuvenated with PEP even after prolonged liquid storage.

2,3-Diphosphoglycerate↗
PubMed1992

Telescience testbed examination aboard Japanese Experiment Module (JEM): life and material science experiments.

A telescience ground testbed experiment was conducted by the National Space Development Agency of Japan (NASDA) at the Tsukuba Space Center in March 1991. The objectives of the ground testbed experiment were to extract scientists' requirements for a communication method, to evaluate the influence of transmission delay and capacity on experiment operations, and to evaluate performance and functions of the system for the testbed experiment. The microscopic operations experiment, the image furnace experiment and the onboard training experiment were selected as typical ground testbed experiments. In these experiments, motion video transmission at 320 kbps was acceptable for observing the experiments and communicating between the principal investigator and the payload specialist. In the microscopic operations experiment, motion video transmission at 1.5 Mbps or more was required for detailed observation. A 4-second transmission delay (roundtrip) was allowable for mutual communication.

Aerospace Medicine↗
PubMed1992

Expression of sialic acids in the developing murine tubotympanum.

Sialoglycoconjugates in the developing murine tubotympanum were characterized using lectin histochemistry with wheat germ agglutinin (WGA), Limax flavus agglutinin (LFA), Sambucus nigra agglutinin (SNA), Maackia amurensis agglutinin (MAA), peanut agglutinin (PNA), and neuraminidase treatment. WGA, LFA, MAA, and neuraminidase-PNA labeled epithelial goblet cells, glandular mucous cells, and cell surfaces of adult and newborn murine tubotympanum. SNA did not label any secretory components. PNA labeled secretory cells and cell surfaces of the fetal tubotympanum without neuraminidase treatment. After birth, these secretory cells and cell surfaces were labeled with PNA only after neuraminidase treatment. These results revealed that: Sialoglycoconjugates are produced from glandular mucous cells and epithelial goblet cells and are present on cell surfaces and within the mucous blanket; their terminal tri-saccharide linkage appears to be the sequence Neu5Ac(alpha 2-3)Gal(beta 1-3)GalNAc; sialic acids appear before birth and gradually increase; terminal galactose residues are masked by sialic acids after birth.

Aging↗
PubMed1992

Ciliary beat of cultured human respiratory cells studied with differential interference microscope and high speed video system.

The ciliary beating of upper respiratory tract cells cultured on cover glasses was studied by using differential interference microscope equipped with high speed video. By culturing the cells on collagen coated cover glasses, objectives with higher magnifications could be used. With this system we could evaluate not only ciliary beat frequency, but also amplitude, wave form, orientation and synchrony of ciliary beating. Also some structural anomalies such as compound cilia and tide cilia bundles could be recognized. Ciliary beat frequency measured from 1,026 ciliated cells was 20.6 +/- 4.7 Hz (mean +/- SD). The orientation of ciliary beat directions was random and the mean standard deviation for measured angles was 73.0 degrees +/- 28.9 degrees (mean SD +/- SD). When the ciliary beat frequency was 20 Hz, the time used for effective phase was 0.022 +/- 0.002 s (mean +/- SD), and 0.028 +/- 0.004 s (mean +/- SD) for the recovery phase of beat. This system is advantageous for studying ciliary function because all parts can be studied simultaneously with higher magnification, and the effects of chemical physical mediators can be studied without disturbing effects of the autonomic nervous system or secretory cells. Also, the same cells could be observed before and after challenge with test medication and thus evaluated more accurately.

Cilia↗
PubMed1992

Retention fluids of chronic sinusitis induce neutrophil adherence to microvascular endothelial cells.

The adherence of circulating leukocytes to the vascular endothelium is a critical step in the emigration of leukocytes through blood vessel walls to inflammatory lesions. The influence of nasal secretions on the adherence of neutrophils to the vascular endothelium was investigated using monolayers of human mucosal microvascular endothelial cells derived from the inferior turbinate. Preincubation of vascular endothelial cells with retention fluids from the maxillary sinus of the patients with chronic sinusitis showed increased neutrophil adherence. Recombinant IL-1 beta was also tested and found to induce adherence of neutrophils to human mucosal microvascular endothelial cells. However, no adhesive effect was observed with the nasal secretions of nasal allergy. An enzyme-linked immunosorbent assay detected considerable amounts of IL-1 beta in the chronic sinusitis retention fluids, while the amounts of IL-1 alpha and TNF-alpha were very low. The increased adhesion of the neutrophils by the retention fluids of chronic sinusitis was also neutralized by the incubation with anti-IL-1 beta antibody in a dose dependent manner. These findings suggest that IL-1 beta in the paranasal secretion of chronic sinusitis induces the adherence of neutrophils to vascular endothelium and subsequent infiltration of neutrophils in the paranasal sinuses, thus contributing to the persistence of chronic sinusitis.

Cell Adhesion↗