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Biomedical subjects

K Honda

Publications and source records attributed to K Honda.

At least 235 records · Page 13Linked to original sources
PubMed1998

Body composition analysis of cachectic rabbits by total body electrical conductivity.

A simple formula (1.536 x TOBEC + 475.146 = LBM, where TOBEC is total body electrical conductivity and LBM is lean body mass) to estimate LBM in grams was developed on the basis of the total body fat data obtained by ether extraction and TOBEC in normal rabbits. The formula was also applicable to rabbits with cachexia induced by inoculation of VX2 carcinoma or by starvation. We were able to assess the losses of body fat in the rabbits with cachexia at 10-day intervals by using TOBEC.

Animals↗
PubMed1998

Essential role of IL-7 receptor alpha in the formation of Peyer's patch anlage.

We investigated the role of IL-7 receptor alpha (IL-7Ralpha) signal in the formation of Peyer's patch (PP) anlage. Although pan-lymphopenia is a common phenotype of rag2-/- and il7ralpha-/- mice, a close inspection revealed nodules corresponding to PP in the adult rag2-/- but not in the il7ralpha-/- mouse. In our previous study, three histologically distinct steps in the formation of PP were identified. The first is the appearance of VCAM-1 + spots in the intestine, which probably represents an initial stage of the formation of the PP anlage. Accumulation of cells bearing IL-7Ralpha, CD4 or Ia in this region then follows and eventually entry of mature lymphocytes expressing CD3 or B220 occurs just before birth. Based on this criterion, we next investigated which of these events is defective in mice with severe combined immunodeficiency. Formation of VCAM-1 + spots and cluster formation of IL-7Ralpha+ cells proceed normally in the rag2-/- mouse which completely lacks mature lymphocytes. In contrast, no VCAM-1+ spots were detected in the embryonic nor neonatal il7ralpha-/- mice, suggesting that IL-7Ralpha signal is involved in the early phase of PP anlage formation. The same defect was found in the jak3-/- mouse. In addition to the appearance of VCAM1+ spots, the clustering of IL-7Ralpha+ cells was absent in the jak3-/- mouse, though IL-7Ralpha+ cells are found to scatter over the intestine. These results indicate that IL-7Ralpha is an essential signal for an early step of PP anlage formation, without which the subsequent processes cannot be initiated.

Animals↗
PubMed1998

Increased proliferation of myoblasts after cyclic plasma perfusion of tumor-bearing rabbits.

Rabbits implanted with VX2 carcinoma and treated by cyclic plasma perfusion showed lower weight loss and longer survival than untreated rabbits. The urinary 3-methylhistidine/creatine ratio was less elevated in the treated rabbits than in the untreated rabbits. Myoblasts from untreated rabbits with VX2 carcinoma showed lower proliferation than those from normal rabbits, while those from rabbits treated by cyclic plasma perfusion showed intermediate proliferation. Furthermore, the DNA synthesis rate of myoblasts from treated rabbits was much better maintained than in the case of untreated rabbits.

Animals↗
PubMed1998

Priming effect of RANTES on eosinophil oxidative metabolism.

BACKGROUND: RANTES has been shown to possess chemotactic activity for eosinophils, which have also been considered to play a role in allergic inflammation through reactive oxygen species. Thus, in this study, we examined the effect of RANTES on radical oxygen products from eosinophils. METHODS: Purified eosinophils by CD16-negative selection or an eosinophilic cell line (EoL-1) were incubated with or without RANTES (2.5 x 10(-6) M). To the mixture of eosinophils and luminol, calcium ionophore (A23187) or opsonized zymosan (OZ) was added, and radical oxygen products were determined by luminol-dependent chemiluminescence for 600 s. RESULTS: Eosinophil-mediated radical oxygen products of untreated eosinophils produced with A23187 gave a peak value of 14.09 +/- 2.40 (mean +/- SE, n = 12) relative light units (RLU) and an integrated value of 3232.20 +/- 513.09 RLU. However, with treatment with RANTES, a peak value of 18.66 +/- 2.40 RLU and an integrated value of 5301.05 +/- 561.02 RLU were obtained. Eosinophil oxidative metabolism-induced A23187 or OZ was apparently augmented by the preincubation with RANTES. In addition, the radical oxygen products of EoL-1 showed similar results. CONCLUSIONS: Thus, we concluded that RANTES may play an important role in the pathogenesis of allergic inflammation through its involvement in eosinophil activation, as evidenced by oxygen products, as well as in selective eosinophil infiltration as selective eosinophil chemoattractant.

Calcimycin↗
PubMed1998

An experimental study of the open end correction coefficient for side branches within an acoustic tube.

The open end correction coefficient (OECC) of acoustic tubes has been widely investigated under a free-field condition. This study examines OECCs in confined regions, such as side branches within the vocal tract. To do this, a number of mechanical acoustic models are used to examine the effects of the angle of the branch axis and the proximity of the walls of the main tract to the open end of the branch. The OECC is estimated by matching both the peaks and troughs (i.e., spectral maxima and minima) of the computed and measured transfer functions for each model. The results indicate that the OECC of a side branch depends on L/D, where L is the cross dimension of the main tract at the branching point, and D is the branch diameter. For side branches connected to the main tract through a narrow neck, the OECC of each end of the neck is determined using the ratio of the radius of the neck to that of the adjacent section. Two empirical equations for evaluating the OECC within a tract are derived from the present study. Finally, the range of appropriate OECC values for estimating an accurate vocal tract transfer function is discussed, based on the results presented here and morphologic measurements reported previously.

Ear↗
PubMed1998

Vowel posture normalization.

A simple normalization procedure was applied to point-parametrized articulatory data to yield quantitative speaker-general descriptions of "average" vowel postures. Articulatory data from 20 English and 8 Japanese speakers, drawn from existing x-ray microbeam database corpora, were included in the analysis. The purpose of the normalization procedure was to minimize the effects of differences in vocal tract size and shape on average postures derived from the raw data. The procedure resulted in a general reduction of cross-speaker variance in the y dimension of the normalized space, within both language groups. This result can be traced to a systematic source of variance in the y dimension of the raw data (i.e., palatal height) "successfully removed" from the normalized data. The procedure did not result in a comparable, general reduction in cross-speaker variance in the x dimension. This negative result can be traced partly to the new observation that some speakers within the English sample habitually placed their tongues in a fronted position for all vowels, whereas other speakers habitually placed their tongues in a rearward position. Methods for evaluating articulatory normalization schemes, and possible sources of interspeaker variability in vowel postures, are discussed.

Adult↗
PubMed1998

Power Doppler findings of adenoma malignum of uterine cervix.

Adenoma malignum (minimum deviation adenocarcinoma) is a rare neoplasma of the uterine cervix, the diagnosis of wich cannot be determined by cervical smear. Recently, magnetic resonance imaging (MRI) was reported as useful for its diagnosis, but differentiation of adenoma malignum from deep-seated nabothian cysts remains problematic. We report here a case of adenoma malignum of the uterine cervix, for which MRI findings could not neglect deep-seated nabothian cysts. However, transvaginal power Doppler ultrasonography clearly showed richness of small vessels, whose arterial flow had higher velocity in the diastolic phase, around the cystic lesion of the uterine cervix. These findings indicate that, at least in the case reported here, transvaginal power and pulsed Doppler ultrasonography is a useful tool for the diagnosis of adenoma malignum of the uterine cervix.

Adenocarcinoma↗
PubMed1998

Eicosapentaenoic acid inhibits mitogen-induced endothelin-1 production and DNA synthesis in cultured bovine mesangial cells.

The present study was designed to examine whether eicosapentaenoic acid (EPA) inhibits the production of basal or stimulated endothelin (ET)-1 by platelet-derived growth factor (PDGF)-BB or epidermal growth factor (EGF), and DNA synthesis in cultured bovine mesangial cells. PDGF-BB and EGF stimulated ET-1 secretion in a dose-dependent fashion in these cells. EPA (10-100 microM) exhibited dose-related inhibition of PDGF-BB- and EGF-stimulated ET-1 secretion. EPA had no inhibitory effects on basal ET-1 secretion in these cells. Moreover, 50 microM EPA significantly attenuated PDGF-BB- and EGF-stimulated [3H]thymidine incorporation into mesangial cells. Receptor-binding experiments showed that EPA competitively inhibited 125I-PDGF-BB or 125I-EGF binding to mesangial cell surface receptors. Scatchard analysis for PDGF-BB receptor or EGF receptor revealed a linear regression fit and one binding site. Pretreatment with 50 microM EPA suppressed the number of maximum binding sites, but did not affect the Kd values. These results indicate that EPA potentially inhibits mesangial cell ET-1 production, when stimulated by PDGF-BB or EGF. This inhibitory effect of EPA could be related to the attenuation of mesangial cell proliferation via inhibition of the binding of PDGF-BB or EGF to their receptors due to alteration of the physicochemical characteristics of the cell membrane.

Animals↗
PubMed1998

RANTES augments eosinophil lucigenin-dependent chemiluminescence.

BACKGROUND: RANTES (regulated on activation, normal T expressed and secreted) has been shown to possess chemotactic activity for eosinophils. Eosinophils have been considered to play a key role in the allergic inflammation through the release of inflammatory molecules such as radical oxygen products. Thus, in this study, we examined the effect of RANTES on radical oxygen products from eosinophils. METHODS: Eosinophils were isolated from heparinized venous blood of patients with bronchial asthma by the modified CD16-negative depletion method. Radical oxygen products were examined in terms of lucigenin-dependent chemiluminescence. To a mixture of 50 microl of eosinophils (2x10(6)/ml) and 50 microl of lucigenin (5x10(-4)M), 50 microl of calcium ionophore A23187 (final concentration 10(-5)M) was added, and radical oxygen products were determined for 600 s. RESULTS: RANTES treatment resulted in the enhancement of peak value (0.64+/-0.23 RLU) and integrated value (119.08+/-20.52 RLU) as compared to untreated cells (0.15+/-0.03 RLU, 29.48+/-8.92 RLU, respectively). CONCLUSIONS We could conclude that RANTES might play an important role in the pathogenesis of allergic inflammation through involvement in selective eosinophil infiltration and eosinophil activation by augmentation of eosinophil oxidative metabolism.

Acridines↗
PubMed1998

Changes in adrenocorticotropic hormone (ACTH) release from the cultured anterior pituitary cells of streptozotocin-induced diabetic rats.

We examined ACTH release from cultured anterior pituitary cells of streptozotocin (STZ)-induced diabetic rats. Rats 1 week after the injection of STZ (55 mg/kg, i.v.) were used as a short-term diabetic model, while rats 8 weeks after the injection of STZ were used as a long-term diabetic model. ACTH release induced by corticotropin-releasing factors (CRF) was significantly increased in the short-term diabetic rats, whereas ACTH release decreased in the long-term diabetic rats. A stimulator of adenylate cyclase, forskolin, caused marked increases in ACTH release in short-term diabetic rats, whereas it did not affect the long-term diabetic rats. An L-type Ca2+ channel agonist, BAY K 8644, did not affect ACTH release in the short-term diabetic rats, although it decreased ACTH release in long-term diabetic rats. In addition, CRF-induced ACTH release also increased in normal anterior pituitary cells cultured under high glucose conditions (25 mmol/L) for 5 d. These results suggest that the increase in the CRF-induced ACTH release from cultured anterior pituitary cells of short-term diabetic rats appears to involve the cAMP system in part. In contrast, the decrease in the CRF-induced ACTH release from the cultured anterior pituitary cells of long-term diabetic rats may indicate a change in the properties of the L-type Ca2+ channel coupled with the CRF receptor, or in the CRF receptor itself.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1998

Further investigation of phenanthroindolizidine alkaloids from Tylophora tanakae.

In addition to ten alkaloids previously described, we have isolated two alkaloid N-oxides from Tylophora tanakae MAXIM. (Asclepiadaceae). Further, the polar fraction of the leaves and caules of this plant cultivated in a farm afforded two new polar alkaloids. The structures of the four products were determined. The relation between the structure and cytotoxic activity of this group of alkaloids is discussed.

Alkaloids↗
PubMed1998

[Effects of arginine-vasopressin on neuronal interaction from the area postrema to the nucleus tractus solitarii in rat brain slices].

The effects of vasopressin (AVP) on area postrema (AP) neurons and the neuronal connection between the AP and nucleus tractus solitarii (NTS) were investigated electrophysiologically in slices preparation of the medulla oblongata of rats. In the AP, 27.9% of 129 neurons were excited by AVP and 20.5% were inhibited. The excitation was blocked by a V1 receptor antagonist. Synaptic transmission of the AP to the NTS was mainly mediated by non-NMDA receptors. Local application of AVP to the AP activated the NTS neurons. This activation was blocked by an NMDA antagonist. These results suggest that the excitation originating in the AP is conveyed to the NTS via non-NMDA receptors and modified by NMDA receptor activation secondly. These processes may be important in regulation of the arterial baroreceptor reflex.

Animals↗
PubMed1998

Haematological and serum biochemical values in spontaneously epileptic male rats and related rat strains.

Haematological and serum biochemical measurements in male spontaneously epileptic rats (SER; double mutants homozygous for zitter and tremor genes) were compared with the values for related rat strains. Some haematological values were low in TRM rats and total leukocyte counts were high in ZI and TRM rats. TRM rats showed higher total cholesterol, phospholipid, high-density lipoprotein cholesterol and calcium values, and lower albumin value than Kyo: Wistar rats. Zitter homozygous rats including SER exhibited low total cholesterol, phospholipid and high-density lipoprotein cholesterol values. The SER showed an increase in urea nitrogen, aspartate aminotransferase and alanine aminotransferase values, and a decrease in glucose value, suggesting deterioration of the whole body with age.

Animals↗
PubMed1998

Plasma adrenomedullin levels in patients with non-insulin dependent diabetes mellitus: close relationships with diabetic complications.

The present study was undertaken to determine plasma adrenomedullin levels in patients with non-insulin dependent diabetes mellitus (NIDDM) to elucidate the potential involvement in the pathogenesis of diabetic complications. The patients were 24 males and 21 females with ages of 55 +/- 2.1 years (mean +/- SEM). Plasma adrenomedullin levels were 5.94 +/- 0.44 pmol/l in patients with NIDDM, and were not affected by plasma glucose concentration. The plasma adrenomedullin increased dependent on the severity of diabetic nephropathy and retinopathy. Plasma levels of adrenomedullin positively correlated with various parameters, including serum creatinine levels, urinary excretion of protein, and systolic blood pressure. In contrast, there were negative correlations between the coefficient variation (CV) of RR intervals and plasma adrenomedullin, and between the conduction velocity of ulnar nerves and plasma adrenomedullin levels. These results indicate that the increase in plasma adrenomedullin was closely related to diabetic complications, which may be dependent on the development of microangiopathy.

Adrenomedullin↗