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Biomedical subjects

K Honda

Publications and source records attributed to K Honda.

At least 289 records · Page 16Linked to original sources
PubMed1997

Measurement of hemodynamics of auditory cortex using magnetoencephalography and near infrared spectroscopy.

Near infrared (NIR) spectroscopy, a non-invasive optical method for monitoring hemodynamics, was applied to record evoked auditory response of the human brain. Our newly developed system detected the amount of oxygenated and deoxygenated hemoglobin in the area of the local brain located beneath the probes. In the study, we used magnetoencephalography (MEG) and NIR spectroscopy to observe the blood component change near the auditory cortex. The sound stimulus of 1 kHz sine wave at 70 dB SPL was used to elicit evoked responses in both experiments. The active region of the auditory cortex was determined by MEG, and the same area was examined by the NIR system. The results from the NIR experiments showed significant increases of total hemoglobin and deoxygenated hemoglobin, indicating that both blood flow and oxygen consumption at the cortical area increased in response to the sound stimuli. The NIR recordings at the two different depths revealed that the increases of local blood flow and oxygen consumption were observed at depths ranging between 20 and 30 mm from the scalp.

Adult↗
PubMed1997

Aggressive natural killer (NK) cell lymphoma: report of a pediatric case and review of the literature.

We report a rare pediatric case of aggressive natural killer (NK) cell lymphoma, characterized by acute onset hepatosplenomegaly and respiratory distress, and infiltration by large granular lymphocytes with the phenotype of CD3-CD16-CD56+. The patient has remained in complete remission after short-pulse intensive chemotherapy, and myeloablative therapy followed by allogeneic bone marrow transplantation. We compare our case with 7 other children with NK cell leukemia reported from other institutions.

Adolescent↗
PubMed1997

Co-secretion of parathyroid hormone and parathyroid-hormone-related protein via a regulated pathway in human parathyroid adenoma cells.

Parathyroid-hormone-related protein (PTHrP) is widely expressed not only in malignant tumors but also in both epithelial and nonepithelial cells of normal tissues. Secreted PTHrP is suspected to act as a paracrine or autocrine regulator. However, little is known about its secretory pathway. To cast light on this question, we studied the intracytoplasmic distribution of parathyroid hormone (PTH) and PTHrP immunohistochemically and immunoelectron microscopically in 10 surgically resected parathyroid adenomas. Double immunostaining was performed using anti-PTH antibody and a newly established anti-PTHrP antibody to reveal the relationship between their two distributions. Additional examination by cell immunoblot assay was performed to determine whether both PTH and PTHrP are secreted simultaneously. Both PTH and PTHrP were actually secreted from individual parathyroid cells simultaneously on cell immunoblot assay. Immunohistochemically, there were two different types of adenoma cells, i.e., one positive only for PTH and the other positive for both PTH and PTHrP. PTH was distributed linearly or fine granularly along the cytoplasmic membrane, whereas PTHrP was distributed diffusely or coarse granularly in the cytoplasm. The intracytoplasmic distributions of PTH and PTHrP often overlapped. Immunoelectron microscopical examination demonstrated that PTHrP co-localized with PTH in the same secretory granules. The results clearly demonstrated that PTHrP can be co-secreted with PTH via a regulated pathway using secretory granules.

Adenoma↗
PubMed1997

[Syndrome of inappropriate secretion of antidiuretic hormone associated with miliary tuberculosis].

An 82-year-old man with the chief complaint of anorexia was referred on suspicion of pulmonary tuberculosis. He had undergone thyroidectomy because of thyroid cancer 5 years ago, had taken levothyroxine sodium, and had kept plasma level of thyroidal hormone within normal range. He had never pointed out hyponatremia. On laboratory findings on admission, serum natrium level was 125 mEq/l. A chest X-ray film showed the infiltration in both lower lung fields, and a chest CT scan revealed a miliary pattern in both lungs. Tubercle bacilli were detected from the sputum by the Ziehl-Neelsen staining. Antituberculous drugs were started. On 5th hospital day, he developed consciousness disturbance, and the serum level of natrium and osmolarity was 103 mEq/l and 250 mOsm /kgH2O, respectively, while plasma ADH level was increased to 5.9 pg/ml, and urine level of natrium and osmolarity was 123 mEq/l and 394 mOsm/kgH2O, respectively. His mental disturbance and hyponatremia gradually improved by supplementing NaCl. We diagnosed this case as SIADH associated with miliary tuberculosis. SIADH should be considered when hyponatremia was occurred in the case of miliary tuberculosis.

Aged↗
PubMed1997

[Effects of recombinant human erythropoietin (rHuEpo) on the interactions between glomerular endothelial cells and mesangial cells: regulation of cell proliferation via endothelin (ET)-1].

To elucidate the effects of recombinant human erythropoietin (rHuEpo) on the interactions between glomerular endothelial cells (GENs) and mesangial cells (GMCs), we investigated whether or not cultured bovine GENs alter endothelin (ET)-1 secretion from bovine MCs and MC proliferate under basal or rHuEpo-stimulated conditions. Incubation for 24 hours with synthetic ET-1 stimulated MC in a dose-dependent manner. In addition, 100 pg/ml of ET-1 significantly stimulated MC proliferation after more than 12 hours incubation. Moreover, rHuEpo stimulated ET-1 secretion from GENs in a dose-dependent manner and showed less stimulation of ET-1 secretion from GMCs than GENs. DNA synthesis in both GENs and GMCs was significantly stimulated with more than 5 U/ml of rHuEpo. ET-1 secretion from GENs co-cultured with GMCs was higher than that from cultured GENs only. Conditioned medium, obtained from co-culture of GENs and GMCs, stimulated the proliferation of GMCs that were significantly inhibited with 10(-6) M approximately 10(-5) M BQ-123, a ETA receptor antagonist. These results suggest that rHuEpo directly stimulates the proliferation of GENs and GMCs, and this stimulatory effect is in part due to ET-1 secreted from these cells, especially GENs.

Animals↗
PubMed1997

[An autopsy case of carbon dioxide intoxication].

A 44-year-old male, engaged in the transportation of dry ice, was found dead on the floor of the freezer of his refrigerator car which was parked in front of the place where he was scheduled to make a delivery. Autopsy was performed to investigate the cause of death. Apart from the signs of acute death, no other significant findings were obtained, either macro or microscopically; carbon dioxide poisoning was thus strongly suspected. We created a simulation experiment by using the refrigerator car to reproduce the events of the accident. The oxygen concentration in the freezer was 21.0% as indicated by oxygen sensors, but decreased to 17.1-17.4% when the engine was stopped. This decrease in oxygen concentration supposedly results from the production of carbon dioxide by the vaporization of dry ice. Carbon dioxide concentration in the air could be calculated from the change in the oxygen concentration in the closed space of the freezer. The concentration was assessed at 17.1-18.6%. An oxygen concentration of 17.1-17.4% does not of itself cause serious hypoxia, but a carbon dioxide concentration of 17.1-18.6% probably causes serious intoxication, because this value is beyond that of intoxication levels published in references. Therefore, we concluded that the cause of death in this case was carbon dioxide intoxication.

Adult↗
PubMed1996

Improved thermodynamic parameters and helix initiation factor to predict stability of DNA duplexes.

To improve the previous DNA/DNA nearest-neighbor parameters, thermodynamic parameters (deltaH degrees, deltaS degrees and deltaG degrees) of 50 DNA/DNA duplexes were measured. Enthalpy change of a helix initiation factor is also considered though the parameters reported recently did not contain the factor. A helix initiation factor for DNA/DNA duplex determined here was the same as that of RNA/RNA duplex (deltaG degrees(37) = 3.4 kcal/mol). The improved nearest-neighbor parameters reproduced not only these 50 experimental values used here but also 15 other experimental values obtained in different studies. Comparing deltaG degrees(37) values of DNA/DNA nearest-neighbor parameters obtained here with those of RNA/RNA and RNA/DNA, RNA/RNA duplex was generally the most stable of the three kinds of duplexes with the same nearest-neighbor sequences. Which is more stable between DNA/DNA and RNA/DNA duplexes is sequence dependent.

Chromatography, High Pressure Liquid↗
PubMed1996

Afferents originating from the dorsal penile nerve excite oxytocin cells in the hypothalamic paraventricular nucleus of the rat.

Electrical stimulation of the dorsal penile nerve (DPN) produced orthodromic excitation in about half of oxytocin cells in the paraventricular nucleus (PVN). In contrast, less than 10% of vasopressin cells were excited. Tactile stimulation of the glans penis by a paintbrush produced excitation in 40% of oxytocin cells. Castration did not prevent activation of oxytocin cells. These results suggest that somatosensory information from the penis is transmitted to the PVN through the DPN and that such afferent input preferentially innervates oxytocin cells.

Afferent Pathways↗
PubMed1996

State-dependent changes of extracellular glutamate in the medial preoptic area in freely behaving rats.

Microdialysis technique was applied to the medial preoptic area (mPOA) of the hypothalamus, a crucial site for the regulation of sleep, in order to analyze the interrelationship between the extracellular level of glutamate (Glu) and the vigilance states. Dialysates from the mPOA were sampled at 5-min intervals for 2-h diurnal period with a perfusion rate of 2.0 microliters/min in freely moving rats, whose sleep-waking behaviors were polysomnographically monitored. Extracellular Glu increased during wakefulness, exhibiting a peak at the transition period from wakefulness to non-rapid-eye-movement sleep (NREMS) (18.0% above the average), whereas it decreased during NREMS (9.2% below the average). It is likely that Glu in the mPOA is dynamically involved in the alterations of the vigilance states.

Animals↗