Search PubMed⌕ Search

Biomedical subjects

Y Miyaoka

Publications and source records attributed to Y Miyaoka.

At least 19 recordsLinked to original sources
PubMed2005

Analysis of head movements coupled with trunk drift in healthy subjects.

Accelerometers were used to measure sequential head tilt and trunk drift in 14 healthy young subjects while they performed three kinds of head task. First, maximum inclination angles in anterior, posterior, right and left directions were measured to estimate cervical ranges of motion for flexion-extension and lateral bending. The inclination angles measured (61.2 degrees on average for flexion, 51.7 degrees for extension, 42.7 degrees for right bending and 43.9 degrees for left bending) were consistent with previous findings. Secondly, cross-correlation analysis was applied to evaluate the degree of functional coupling between the head and trunk during flexion-extension and lateral bending. Significantly higher correlation coefficients were found between head tilt and trunk drift when these movements were in the same (iso-) directional condition than in a different (allo-) directional condition. The coupled trunk drift in flexion-extension for the iso-directional condition (10.3 degrees on average) was much larger than for the allodirectional condition (2.3 degrees). Finally, head turning was recorded as oval traces in a biaxial plane. In both clockwise and counter-clockwise head turning conditions, the maximum inclination angles of the traces were larger in the anterior-posterior direction (59.8 degrees anterior and 58.2 degrees posterior, in the clockwise condition, and 47.4 degrees and 47.4 degrees in the counter-clockwise condition) than in the right-left direction (36.3 degrees right and 39.0 degrees left, in the clockwise condition, and 40.5 degrees and 36.7 degrees in the counter-clockwise condition), and the angles in the four directions were almost equal to flexion-extension and lateral bending. The characteristics of the traces recorded and a possible application of the present recording system are discussed.

Acceleration↗
PubMed2004

Barrett's oesophagus with predominant intestinal metaplasia correlates with superficial cyclo-oxygenase-2 expression, increased proliferation and reduced apoptosis: changes that are partially reversed by non-steroidal anti-inflammatory drugs usage.

BACKGROUND: Cyclo-oxygenase-2 expression has been reported to play an important role in the metaplasia-dysplasia-carcinoma sequence in Barrett's oesophagus. However, the existence of cyclo-oxygenase-2 expressing cells in Barrett's epithelium is still uncertain. AIM: To identify the cells that express cyclo-oxygenase-2 protein and to investigate the relationship between cyclo-oxygenase-2 expression and mucin-phenotype of Barrett's epithelium. METHODS: Sections from 466 biopsy samples of Barrett's epithelium from 358 non-medicated patients were immunohistochemically examined for the cyclo-oxygenase-2 expression, mucin-phenotype, cell proliferation and apoptosis. RESULTS: Cyclo-oxygenase-2 expression was detected in 71.0% of Barrett's epithelium biopsy samples. In Barrett's epithelium with the gastric predominant mucin-phenotype, cyclo-oxygenase-2 expression was mainly found in stromal and deep epithelial cells, whereas in intestinal predominant mucin-phenotype, it was mostly in superficial epithelial cell. A significant elevation of proliferating cell nuclear antigen index and suppression of apoptotic index was observed in Barrett's epithelium with superficial epithelial cyclo-oxygenase-2 expression. Neither such elevation of proliferating cell nuclear antigen index nor the suppression of apoptotic index could be found in chronic non-steroidal anti-inflammatory drugs users. CONCLUSIONS: Barrett's epithelium with intestinal mucin and superficial epithelial cyclo-oxygenase-2 expression possess a higher proliferation potential, but this risk may be thwarted by non-steroidal anti-inflammatory drugs administration.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2004

Head movement associated with performance of mandibular tasks.

The present study was designed to examine the hypothesis that the motor system controlling phonation is functionally coupled with the motor system controlling posture of the head and neck, as previously suggested (U. Haddar, T.J. Steiner, E.C. Grant and F.C. Rose Human Movement Science 2: 35 and Language and Speech 26: 117). Head tilt and trunk drift in the antero-posterior and right-left directions were measured simultaneously for 20 s before and during three types of speech sounds (/pa/, /ta/ and /ka/) as well during a maximum jaw open-close task in 14 healthy young subjects. The major findings obtained in all of the four tasks were: (i) the trunk drift measured in both directions was negligible in comparison with the head tilt; (ii) the head tilt in the antero-posterior direction was much larger than in the right-left direction and (iii) the head tilt during performance of the four tasks consisted of 'initial' and 'sustained' phases. In the initial phase, the head tilted posteriorly in association with the start of individual tasks. In the sustained phase, the head tilted either anteriorly or posteriorly when the task progressed. The magnitude of the net head tilt in the sustained phase negatively correlated with that of the initial head tilt. These findings indicate that phonation, in the form of jaw open-close, accompanies head movement in two consecutive phases.

Adult↗
PubMed2003

Expression of midkine and receptor-like protein tyrosine phosphatase (RPTP)-beta genes in the rat stomach and the influence of rebamipide.

BACKGROUND: Midkine has been reported to bind to receptor-like protein tyrosine phosphatase (RPTP)-beta and to play important roles in growth and differentiation of various cells. Midkine is expressed in rat stomach during experimental ulcer healing, suggesting that the midkine-RPTP-beta system has some physiological functions in the stomach. Rebamipide is a mucoprotective drug used for the treatment of gastric ulcers. We have tested the hypothesis that the ulcer healing mechanism stimulated by rebamipide is linked physiologically to the gastric midkine-RPTP-beta system. MATERIALS AND METHODS: Seven-week-old-male Wistar rats were used. Midkine and RPTP-beta gene expression in rat stomach was investigated by laser capture microdissection coupled with the reverse transcription-polymerase chain reaction (RT-PCR). The effects of rebamipide on midkine and RPTP-beta expression in rat stomach and the gastric epithelial cell line RGM1 were evaluated by RT-PCR and Northern blot analyses. RESULTS: Midkine and RPTP-beta expression was detected in the gastric mucosal, submucosal and muscle layers. Rebamipide stimulated both midkine and RPTP-beta expression in rat stomach and RGM1 cells. CONCLUSION: Rebamipide may protect the gastric mucosa by regulating midkine and RPTP-beta expression.

Alanine↗
PubMed2002

Skin reflectance-spectra and colour-value dependency on measuring-head aperture area in ordinary reflectance spectrophotometry and tristimulus colourimetry.

BACKGROUND/AIMS: Measurement of skin colour has become increasingly popular in the study of dermatology with the increased availability of portable instruments. However, different instruments have been reported as giving different results from measurement of the same skin region. The aim of this study was to examine the effects of differences in measuring-head aperture area on skin reflectance spectra and colour values. METHODS: We measured both reflectance spectra and CIE-L*a*b* values of the skin in five different anatomical regions on 10 subjects using two MINOLTA reflectance spectrometers that were identical apart from the aperture area of the measuring heads (diameters: 5 and 11 mm). For comparison, data were also obtained from a skin-coloured tile. RESULTS: Skin reflectance values measured with the wider-aperture instrument were higher than those measured with the other, irrespective of anatomical location. The differences between the two were near zero at an incident light wavelength of 400 nm, but increased to around 10% of the reflectance value at 700 nm, increasing exponentially with incident light of increasing wavelength. Skin colour was observed to be brighter, redder and yellower, in CIE-L*a*b* expression, when measured with the wider-aperture instrument. The differences between measurements obtained from the skin-coloured tile were much smaller. CONCLUSION: Skin reflectance and colour values measured with reflectance instruments are not absolute data but depend on the aperture area of the measuring head. This is probably due to variations in the proportion of longer-wavelength light reflected from the skin and collected by the instrument.

Adult↗
PubMed2002

Graphic analysis of the relationship between skin colour change and variations in the amounts of melanin and haemoglobin.

BACKGROUND/AIMS: The L*a*b* coordinate is the most commonly used colour system to measure skin colour in dermatology and cosmetology. In this system, a* and L* are often used for quantification of the degrees of erythema and pigmentation. The aim of this study was to examine whether a* and L* can be used as specific scales to indicate the amount of haemoglobin and melanin, respectively, in the skin. METHODS: The a* and L* values were examined with a reflectance spectrometer in various skin conditions or lesions caused by a change in the amount of either melanin or haemoglobin, i.e. vitiligo, ultraviolet-induced pigmentation (PG), erythema resulting from slapping (ER), corticosteroid-induced blanching, erythema due to stasis by arm lowering, and a combination of PG and ER. The differences in values between the test sites and the adjacent normal skin, deltaa* and deltaL*, were plotted on the deltaa*-deltaL* plane and analysed statistically and geometrically. RESULTS: L* depended substantially not only on melanin but also on haemoglobin, especially if the oxygen saturation level was expected to be low. a* was also influenced by melanin. The results of graphic analysis indicated that a linear transformation of (deltaa*, deltaL*) into (deltaHb = 1.68 deltaa* + 0.60 deltaL*, deltaMel =-1.06 deltaa*-1.44 deltaL*) was suitable for separately estimating the change in the amount of haemoglobin (deltaHb) and in that of melanin (deltaMel). CONCLUSION: The results of this study may be of value for understanding the relationship between colour coordinates of the skin and the quantities of haemoglobin and melanin, and may be of use when pigmented lesions of the face are monitored by tristimulus colourimetry, as facial skin colour is affected considerably by the rich and easily variable cutaneous blood flow.

Adult↗
PubMed2002

Activation of prostaglandin E2-receptor EP2 and EP4 pathways induces growth inhibition in human gastric carcinoma cell lines.

The effect of prostaglandin E2 (PGE2) on the proliferation of gastric cancer cells is still unclear. PGE2 receptors are divided into four subtypes - EP1, EP2, EP3, and EP4 - which are coupled to three different intracellular signal-transduction systems. Stimulation of EP2 and EP4 is linked with cyclic adenosine 3', 5'-monophosphate (cAMP)-dependent protein kinase A (PKA). In some human gastric cancer cells, PGE2 has been suggested to have an antiproliferative effect by way of increased cAMP production. Expression of EP2 and EP4 in human gastric carcinoma cells, however, has not been examined. We examined the expression of EP2 and EP4 and the antiproliferative effects of specific EP2 and EP4 agonists on four different human gastric cancer cell lines. Our data clarified that all the cell lines investigated in this study expressed EP2 and EP4 and that the specific agonists of these receptors induced growth inhibition with an accompanying increase in cAMP production. In summary, gastric cancer cells have EP2 and EP4 receptors, and their selective activation is linked with the decreased cell proliferation.

Cell Division↗
PubMed2001

Changes in jaw reflexes by stimulation of the hypothalamus in anesthetized rabbits.

Changes in the masseteric monosynaptic reflex (MMR) and jaw-opening reflex (JOR) responses resulting from conditioning stimulation in the hypothalamus were studied in anesthetized rabbits. Stimulation of the lateral hypothalamus evoked a facilitation of the MMR and an inhibitory or facilitatory effect on the JOR. The facilitatory effect on JOR was stronger than that on the MMR. The facilitatory effective site for the JOR was in the dorsal and lateral directions as compared to the inhibitory field. The results suggest two functionally distinct regions in the lateral hypothalamus that separately project to the jaw-opening muscles.

Aggression↗
PubMed2001

Localized heat urticaria: a clinical study using laser Doppler flowmetry.

We studied the pathophysiology of localized heat urticaria using laser Doppler flowmetry (LDF) in two patients with this rare disease. In heat challenge tests, performed with different challenge times and temperatures, a heat stimulator with a thermoregulated metal disc was utilized. Immediately after removal of the heat source, cutaneous blood flow (CBF) changes in the tested sites were monitored with LDF. In both patients the increase in (CBF) took place at some intervals after a heat challenge, synchronous with the start of the urticarial response. This interval, or the latency time (LT), showed distinct inverse proportion to the intensity of heat stimuli and was prolonged by effective treatments, such as application of antihistamines and repeated heat exposure by LDF. Therefore, the time of latency might be regarded as a good indicator of the severity of illness and therapeutic effectiveness, and thus might reflect the relationship between the degree of heat stimuli and the releasing process of chemical mediator(s) in patients with localized heat urticaria (LHU).

Administration, Topical↗
PubMed1999

Sweet's syndrome associated with chronic myelogenous leukemia: demonstration of leukemic cells within a skin lesion.

We report a case of acute febrile neutrophilic dermatosis, Sweet's syndrome, associated with chronic myelogenous leukemia (CML) in which we found rearrangement of the bcr gene in DNA obtained from a skin lesion as well as in blood DNA by Southern blot analysis. This indicated the presence of CML cells within the skin lesion. To our knowledge, this is the first report in which the presence of CML cells is shown within skin lesions of Sweet's syndrome. In our patient, leukocyte alkaline phosphatase activities returned to normal levels when he was suffering from Sweet's syndrome and decreased again to below normal levels after it subsided. Whether the normalization of leukocyte alkaline phosphatase activity is common among CML patients with Sweet's syndrome remains to be determined.

Blotting, Southern↗
PubMed1998

Reflexogenic areas for velopharyngeal closure in rabbits.

Responsive areas for velopharyngeal closure were examined by recording diaphragmatic and superior pharyngeal constrictor activities of anesthetized rabbits. Pressure stimulation was applied with a cotton applicator to the mucosae of three pharyngeal areas: the anterior (palatal) and posterior walls of the nasopharynx and the posterior wall of the oropharynx. The intensity and duration of the stimulation were around 9.0 gf and 0.43 sec, respectively. Velopharyngeal closure was elicited more frequently from the posterior wall of the nasopharynx than the other two areas tested. The higher responsiveness of the posterior wall of the nasopharynx for velopharyngeal closure is suggested to be attributed to higher density and/or lower threshold of pressure receptors in this area than those in the other two areas tested. Possible physiological implications of the present results are discussed.

Animals↗
PubMed1998

Responses of neurons in the parabrachial region of the rat to electrical stimulation of the superior laryngeal nerve and chemical stimulation of the larynx.

The responsiveness of the parabrachial region to electrical stimulation of the superior laryngeal nerve was first examined in anesthetized rats. Action potentials were recorded in 30 parabrachial sites by single and train electrical pulses to the superior laryngeal nerve. The average latency, from the onset of stimulation to the first action potentials, was 9.9 ms (range, 6.5-18.8 ms). The responsiveness of parabrachial neurons to chemical stimulation of the laryngeal region was next examined using anesthetized, immobilized, and artificially ventilated rats in which the chorda tympani and glossopharyngeal nerves were bilaterally sectioned. Taste stimuli were applied to the laryngeal region through a tracheal tube and rinsed with 0.15 NaCl. A total of 66 responses were recorded from 26 neurons. The most effective stimulus for these neurons was 0.03 M hydrochloric acid, followed by 0.01 M quinine hydrochloride, 0.5 M sodium chloride, 0.5 M sucrose, and distilled water. Seven responses were derived from 0.15 NaCl. These neurons were mainly located in a posterodorsolateral part of the parabrachial nucleus. These results suggest that chemical signals from the laryngeal region are transmitted to the parabrachial nucleus through the superior laryngeal nerve.

Action Potentials↗
PubMed1997

Vagal control of pharyngeal constrictor activity in rabbits.

The neural control mechanism of pharyngeal constrictor (PC) activity of rabbits was examined in relation to vagal afferents. The average firing rate of single PC units of unilaterally vagotomized animals increased from 0.52 to 8.83 spikes/sec by cooling of the intact vagus nerve at 5 degrees C. Time courses of increases in PC and diaphragmatic (Dia) activities were examined during the period from the start of vagal cooling to the time when the PC reached the maximum firing rate. Although Dia activity linearly increased along with the respiratory cycles, PC activity slowly increased during the first three-quarters of the period and rapidly increased during the last quarter. The result suggests that more impulses in the vagus nerve are required to be blocked by cooling at a lower temperature for eliciting an increase in PC activity compared with that in Dia activity. The increase in PC activity evoked by bilateral vagotomy (from 0.30 to 10.07 spikes/sec) was not different from that by vagal cooling. The presumable afferent nerve fibers responsible for the increase in PC activity were discussed.

Analysis of Variance↗
PubMed1997

Responses of parabrachial nucleus neurons to chemical stimulation of posterior tongue in chorda tympani-sectioned rats.

Responses of parabrachial nucleus (PBN) neurons (n = 43) to chemical stimulation of the posterior tongue were recorded in chorda tympani (CT)-sectioned rats and compared with those (n = 45) in CT-intact. The chemical stimuli used were 0.5 M sucrose, 0.5 M sodium chloride (NaCl), 0.03 M hydrochloric acid (HCl), 0.01 M quinine hydrochloride, and distilled water. These stimuli were applied to an area posterior to the intermolar eminence of the tongue. Neurons of CT-sectioned rats responsive to the chemical stimuli were located in more caudal areas of the PBN compared with those of CT-intact. Numbers of responses to the five stimuli and breadth of responsiveness to the four basics were not different between both groups of rats. However, average response magnitudes of the neurons in CT-sectioned rats were lower than those in CT-intact. In both groups of rats, the response magnitudes to NaCl and HCl were larger than those to the other three stimuli, and responses to NaCl and those to HCl were highly correlated. It is suggested that glossopharyngeal fibers responding strongly to acids and salts are likely to be the main source of PBN responses from the posterior tongue.

Animals↗
PubMed1997

Impact of sociodemographic and diabetes-related characteristics on depressive state among non-insulin-dependent diabetic patients.

One hundred and fifty-one non-insulin-dependent diabetic patients were assessed to detect sociodemographic, psychological and disease-related characteristics that were related to depressive state among diabetic patients. Depressive state in the patients was correlated with poor social support and low economic status, premorbid neurotic personality and the presence of complications, retinopathy in particular. However, depressive state did not correlate with age, gender, education, serum level of HbA1C or duration of diabetes. The severity of the depressive state in diabetic patients may vary with the cultural background of the patient and/or the country in which he or she is living. In treating diabetic patients, doctors need to pay special attention to these factors.

Adaptation, Psychological↗
PubMed1997

A case of dermatomyositis complicated by thrombotic thrombocytopenic purpura.

A 60-year-old man with dermatomyositis was admitted to our hospital because of dyspnea and hypertension. He had high fever and convulsive seizures after admission. Laboratory examinations showed hemolytic anemia, thrombocytopenia, and renal failure. A clinical diagnosis of thrombotic thrombocytopenic purpura (TTP) was made. He failed to respond to plasma exchange therapy, pulse therapy with methylprednisolone, high-dose gamma-globulin therapy, and antiplatelet therapies with ticlopidine, dipyridamole and a prostacyclin analog of beraprost sodium. He died on his 17th day in hospital. Autopsy examination revealed widespread microthrombi in his kidneys, lungs, spleen, and intestine. Only seven cases of dermatomyositis or polymyositis complicated by TTP have been cited in the literature. TTP was fatal in 6 of these 7 cases. Early diagnosis and prompt treatment may improve the outcome of TTP patients with dermatomyositis. Dermatologists should keep in mind that TTP occasionally arises as a serious complication of dermatomyositis.

Anti-Inflammatory Agents↗