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Biomedical subjects

T Miyahara

Publications and source records attributed to T Miyahara.

At least 163 records · Page 9Linked to original sources
PubMed1992

[The influence of proton-pump inhibitors on the healing process of peptic ulcers--electronic endoscopic study].

It is highly important to analyze the of protonpump inhibitors on the healing process of peptic ulcers endoscopically since the use of proton-pump inhibitors is restricted in their period of usage. It is however, too early to evaluate proton-pump inhibitors as equal to or comparable to the many H2 blockers which have been tested basically and clinically. From the view-point of the number of clinical cases too, it is too early to conclude that the protonpump inhibitors are superior to previous H2 blockers. Most of the ear electronic endoscopic studies are highly conducted with the stereo-type electronic endoscopes except that on the regenerative epitheliums. The pictorial management of the regenerative epitheliums and intramucosal blood volume are not discussed in this paper, but results are expected to in the near future.

Adenosine Triphosphatases↗
PubMed1992

[The general aspects of the treatment of irritable bowel syndrome].

Irritable bowel syndrome (I.B.S.) is treated with medication, change of life style, various psychotherapies, oriental medicine, and etc., But no specific therapy is recognized useful for all the symptoms derived from I.B.S.. In fact the combination of these therapies are useful. When the therapeutic schedule is planned for individuals, we must keep it in mind that the relief from the symptoms is most important for patients.

Anti-Anxiety Agents↗
PubMed1991

Interaction between cadmium and copper on ossification of embryonic chick bone in tissue culture.

To investigate the interaction between cadmium and copper in ossification, femurs from 9-day-old chick embryos were cultured for 6 days in the presence of 2 microM cadmium and/or 1 microM copper. It was found that cadmium + copper treatment caused interactively severe damage to osteogenic mesenchymal cells in the periosteum and a severe degenerative change in osteoblasts around the trabecula, resulting in severe impairment of ossification in the diaphysis. Cadmium content was increased by copper; however, copper content was unaffected by cadmium in the diaphysis. It was therefore considered that the copper-induced increase in cadmium content was a primary factor in the interactive toxic effect of the cadmium + copper treatment in ossification.

Animals↗
PubMed1991

Induction of metallothionein and stimulation of calcification by dexamethasone in cultured clonal osteogenic cells, MC3T3-E1.

To clarify the effects of dexamethasone (Dex) on metallothionein (MT) synthesis and calcification in osteoblastic cells, a clonal osteogenic cell line (MC3T3-E1) was used in the present study. Under culture conditions designed not to cause calcification, MT synthesis of cells at 3 days after inoculation increased with increasing concentration of Dex (2.5-50 nM) for a 24-h culture period. Cells at 6 or 9 days after inoculation also synthesized MT by a 24-h exposure to Dex. These show that undifferentiated osteoblasts have the ability to synthesize MT by Dex. Under culture conditions designed to cause calcification, cells at 6 days after inoculation were cultured with 50 nM Dex in the presence of 7 mM beta-glycerophosphate (beta-GP) for 7 days. Ca content of Dex-treated cells was about 7.5 times as high as that of untreated cells. Dex-treated cells showed a high activity of alkaline phosphatase (ALP). The Zn content of the MT fraction in Dex-treated cells was about 8 times as high as that of untreated cells. These results show that Dex has the ability to induce MT synthesis in osteoblastic cells and to cause a high calcification which is due at least partly to an enhanced activity of ALP.

Alkaline Phosphatase↗
PubMed1991

Large bullous eruption in patients with ulcerative colitis.

Oligocentric large bullous eruptions in two patients with ulcerative colitis were reported. Such bullae were similar to those seen in drug-induced coma, and those described as drug eruption due to high dose frusemide. However, neither narcotic drugs nor frusemide had been given in either case. The bullae were cured after the administration of corticosteroid and/or salazosulfapyridine with a course paralleling that of the ulcerative colitis. Thus the bullae seem to be a cutaneous manifestation of ulcerative colitis.

Adult↗
PubMed1991

Effects of enoxacin and its combination with 4-biphenylacetate, an active metabolite of fenbufen, on population spikes in rat hippocampal slices.

The effects of enoxacin, a new quinolone antibacterial agent, and its combination with 4-biphenylacetate (BPA), an active metabolite of the non-steroidal antiinflammatory agent fenbufen, were examined on population spikes induced by electrical stimulation of the stratum radiatum in the CA1 pyramidal cell layer in rat hippocampal slices. Enoxacin (10(-4) M) and bicuculline (10(-6) M) increased the amplitude of the population spikes and anew elicited the second spikes (latency: 10 msec.), while BPA (10(-5) M) decreased the amplitude of the population spikes. However, the combination of enoxacin (10(-6), 10(-5) M) with BPA (10(-5) M) elicited the second spikes or epileptiform bursts with an increase of the population spike amplitude. The dose-response relationships showed that the effect of enoxacin was 100 times potentiated in the presence of BPA (10(-5) M). The second spikes induced by enoxacin (10(-4) M) were suppressed by muscimol (10(-6) M) and baclofen (10(-6) M), but not by clorazepate (5 x 10(-5) M) and pentobarbital (5 x 10(-5) M). The second spikes induced by bicuculline (10(-6) M) were suppressed by these four drugs. The second spikes by the combination of enoxacin (10(-6) M) with BPA (10(-5) M) were suppressed by muscimol (5 x 10(-6) M), but not by clorazepate (5 x 10(-5) M). These results suggest that the combination of enoxacin with BPA exerts a drug interaction to elicit the second spikes or epileptiform bursts with its mode of action different from that of bicuculline.

Action Potentials↗
PubMed1991

Metabolism of mephentermine in male guinea pigs and male mice.

1. Urinary metabolites of mephentermine (MP), after i.p. administration of MP to male Hartley guinea pigs and mice, were identified by g.l.c.-electron impact (EI) mass spectrometry. Excretion of urinary radioactivity, and metabolites of 3H-MP, after i.p. administration, were determined by preparative t.l.c.-liquid scintillation counting. 2. About 27% of the radioactivity administered was excreted in the 24 h urine of guinea pigs, and 36% dose was excreted in 5 days. In mice, about 47% of the radioactivity was excreted in the 24 h urine, and 52% in 5 days. 3. Excretion rates of metabolites detected in the 24 h urine of guinea pigs were phentermine (Ph, 7.8%), a conjugate of N-hydroxyphentermine (N-hydroxy-Ph, 3.6%), p-hydroxyphentermine (p-hydroxy-Ph, 1.0%) and its conjugate (2.9%), and other metabolites (conjugates of MP and Ph, N-hydroxymephentermine (N-hydroxy-MP) and its conjugate, p-hydroxymephentermine (p-hydroxy-MP) and its conjugate, and N-hydroxy-Ph; less than 1.0%). The rates of excretion for mice were Ph (11.7%), conjugates of p-hydroxy-MP (3.1%), Ph (2.7%) and p-hydroxy-Ph (1.6%), and N-hydroxy-Ph (1.2%) and other metabolites (conjugates of MP and N-hydroxy-Ph, N-hydroxy-MP and its conjugate, p-hydroxy-Ph, and p-hydroxy-MP; less than 1.0%). 4. These results indicate that MP administered to mice is metabolized mainly to Ph and p-hydroxy-MP by N-demethylation and p-hydroxylation of the parent compound, and in guinea pigs the primary metabolic reaction of MP is N-demethylation producing Ph.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Modulation of soleus H-reflex by teeth clenching].

Modulation of the human soleus H-reflex (Sol. H-R) was studied during voluntary teeth clenching in 11 healthy adult volunteers, to investigate the possible correlation of motor functions between the jaw and body. The following results were obtained: (1) Sol. H-R was facilitated during the maximum voluntary teeth clenching more than during the maximum voluntary efforts in the other parts of the body, i.e., Jendrassik maneuver and clenching of both hands. (2) The amount of the Sol. H-R facilitation increased with the masseter EMG activity. (3) Facilitation of the Sol. H-R in association with teeth clenching started ca 60ms before the onset of the masseter EMG activity, reached its peak ca. 100ms after the onset and thereafter decreased to a certain plateau level in accordance with the masseter EMG activity level. (4) During the inhibition of the masseter EMG reflexively evoked by electrical stimulation of the lower lip, the amount of the facilitation of the Sol. H-R during teeth clenching decreased compared with that without lip stimulation, though the facilitation was still retained. It was concluded that: 1) The excitability of the Sol. H-R is remarkably elevated during teeth clenching. 2) There is a positive correlation between the amount of the facilitation of the Sol. H-R and the teeth clenching force level. 3) The facilitation is due to both the descending influence from the higher brain and the afferent inputs from the oral structures. It is assumed that the oral motor activity exerts a strong influence on the bodily motor function in general.

Adult↗
PubMed1991

DNA strand scisson and cell-killing activity of hydroperoxynaphthalimide derivatives upon photoirradiation.

A series of hydroperoxynaphthalimides (1a-1c) and naphthaldiimide (2) that generate hydroxyl radical upon longer wavelength photoirradiation (366 nm) have been devised. They induce DNA strand break at low concentration upon photoirradiation which are inhibited in the presence of hydroxyl radical scavengers such as mannitol or sodium benzoate. The compound 2 showed a sequence specific DNA strand scission at -5'GG-sequence. The formation of 8-hydroxydeoxyguanosine (8-OHdG) is also observed on photoirradiation of 1a or 2 in the presence of dG. The antibacterial activities of these compounds will also be described.

Anti-Bacterial Agents↗
PubMed1990

Prediction of left ventricular function during supine bicycle ergometer exercise in angina-free patients with old myocardial infarction.

We investigated whether or not left ventricular function during dynamic exercise in angina-free patients with old myocardial infarction could be estimated using resting left ventricular function and noninvasive parameters determined during exercise. We studied 70 patients with old myocardial infarction by measuring hemodynamic parameters during supine multistage bicycle ergometer exercise. Coronary arteriography and left ventriculography were performed: then the left ventricular ejection fraction and left ventricular end-diastolic volume were measured. The parametric changes (delta) between rest and peak exercise were determined. Significant positive correlations were observed between cardiac index (CI) at rest and at peak exercise (r = 0.62, p less than 0.001), as well as between pulmonary artery wedge pressure (PAWP) at rest and at peak exercise (r = 0.72, p less than 0.001). Multiple regression analysis indicated that CI and PAWP at peak exercise as dependent variables were best described by the equations: CI at peak exercise = 1.074 [CIrest] +0.031 [delta HR] + 0.004 [ExD] + 0.018 [LVEF] - 1.560 (r = 0.79, p less than 0.001), PAWP at peak exercise = 0.994 [PAWPrest] - 0.181 [LVEF] + 0.203 [delta DBP] -0.076 [delta HR] -21.488 (r = 0.80, p less than 0.001). These data suggested that CI and PAWP during dynamic exercise in angina-free patients with old myocardial infarction could be predicted using noninvasive parameters, such as increments of blood pressure and heart rate as well as exercise duration, together with data on resting left ventricular function, such as resting CI, resting PAWP, and resting left ventricular ejection fraction (LVEF).

Adult↗
PubMed1990

Clinical significance of simple heart rate-adjusted ST segment depression in supine leg exercise in the diagnosis of coronary artery disease.

To evaluate the clinical significance of simple heart rate-adjusted ST segment depression (delta ST/delta HR) in the diagnosis of coronary artery disease, 42 patients with stable exertional angina underwent supine leg exercise testing and cardiac catheterization. During exercise, heart rate, a multilead electrocardiogram, and pulmonary artery wedge pressure were recorded. The sensitivity and accuracy of the delta ST/delta HR criteria (greater than or equal to 3.0 microV/beat/min) were significantly greater than the conventional analysis of ST segment depression criteria (greater than or equal to 0.2 mV) for detecting three-vessel coronary artery disease at a matched specificity of 72% (100% versus 46%, 81% versus 64%, p less than 0.01). A significant linear correlation was found between maximum pulmonary artery wedge pressure increments during exercise (delta PAWP) or Gensini score and the delta ST/delta HR (delta PAWP: r = 0.51, p less than 0.001; Gensini score: r = 0.47, p less than 0.001). There were no statistically significant differences in the delta PAWP or Gensini score between patients with three-vessel disease who had delta ST/delta HR greater than or equal to 3.0 microV/beat/min and those with one- or two-vessel disease who had delta ST/delta HR greater than or equal to 3.0 microV/beat/min (delta PAWP: 18.1 +/- 2.0 versus 21.9 +/- 3.3, p = NS; Gensini score: 68.5 +/- 6.6 versus 66.3 +/- 11.3, p = NS). These findings demonstrate that delta ST/delta HR is more useful than a conventional analysis of ST segment depression for identifying not only anatomically severe coronary artery disease but also functionally severe coronary artery disease.

Adult↗
PubMed1990

Mechanism of abnormal postexercise systolic blood pressure response and its diagnostic value in patients with coronary artery disease.

To define the factors that affect an abnormal postexercise systolic blood pressure (SBP) response and to verify the diagnostic value of that response in patients with coronary artery disease (CAD), we studied 33 normal subjects, eight patients with hypertension who had no CAD, and 42 patients with documented CAD who underwent supine leg exercise testing. SBP recovery ratios were derived by dividing the values obtained 1 and 3 minutes after exercise by the peak value. The upper normal limit of the SBP ratio was defined by two standard deviations from the mean for 33 normal subjects. The specificity of this criterion for identifying patients with CAD was 97% and the sensitivity was 60%. None of the eight patients with hypertension showed an abnormal postexercise SBP response. At peak exercise the pulmonary artery wedge pressure was significantly greater in the patients with CAD having an abnormal response. In multiple regression analysis the exercise pulmonary artery wedge pressure, the exercise SBP, and the systemic vascular resistance after exercise were determining factors for an abnormal SBP response. Three-vessel disease was more common in patients with an abnormal response. Results of this study indicate that an abnormal postexercise SBP response appears to be determined by (1) the extent of exercise-induced impairment of left ventricular function and (2) peripheral vascular tone during recovery. This study also suggests that this criterion can increase the specificity of supine exercise testing in patients with CAD including those with hypertension and might provide a marker for the severity of impaired left ventricular function by exercise in CAD.

Adult↗
PubMed1990

Dynamic exercise-induced elevation in plasma levels of atrial natriuretic peptide in patients with effort angina pectoris.

We investigated the relationship between plasma atrial natriuretic polypeptide (ANP) levels and hemodynamic indices during dynamic exercise testing in 15 patients with effort angina pectoris. Patients exercised on an angina-limited, supine, multistage bicycle ergometer, and plasma ANP levels and hemodynamic indices were measured at rest, at peak exercise, and 6 minutes after exercise. Plasma ANP levels increased significantly at peak exercise. Pulmonary artery wedge pressure (PAWP) and coronary sinus blood flow (CSBF) were significantly correlated with plasma ANP levels before and at peak exercise (PAWP: r = 0.69, p less than 0.001; CSBF; r = 0.45, p less than 0.05). In six of eight patients whose PAWP exceeded 20 mm Hg at peak exercise, plasma ANP levels were increased at 6 minutes after exercise, whereas PAWP had decreased relative to the values obtained at peak exercise. Plasma ANP concentrations at 6 minutes after exercise were not correlated with PAWP at the same time. However, PAWP at peak exercise was correlated with the plasma ANP levels at 6 minutes after exercise (r = 0.80, p less than 0.001). These results suggest that in patients with effort angina pectoris left ventricular dysfunction resulting from exercise-induced myocardial ischemia may increase preload excessively and may contribute to the excess secretion of ANP after dynamic exercise.

Adult↗