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Biomedical subjects

Y Miyahara

Publications and source records attributed to Y Miyahara.

At least 19 recordsLinked to original sources
PubMed2001

Effect of prenatal melatonin exposure on gonadotropins and prolactin secretion in male and female rat pups.

We evaluated whether melatonin administration to pregnant rats during the final week of pregnancy affects prepubertal secretion of luteinizing hormone (LH), follicle stimulating hormone (FSH), and prolactin in offspring. Melatonin was administered in the drinking water from day 14 to delivery. LH, FSH and prolactin concentrations were determined in plasma sampled from offspring between 5 and 30 days in the dark portion of the diurnal cycle. Administration of 2 or 20 microg/ml melatonin did not affect LH or FSH in male or female offspring. The 20-microg/ml dose caused a significant increase in prolactin in males and females at day 15. In contrast, melatonin, 2 or 20 microg/ml, decreased prolactin at days 25 and 30 in females and day 25 in males. Thus, prenatal melatonin exposure alters prolactin secretion, but not that of LH and FSH in infantile and prepubertal male and female rats.

Animals↗
PubMed2001

Limitations of successive transradial approach in the same arm: the Japanese experience.

The transradial approach (TRA) has been used for diagnostic and interventional cardiology. It has not previously been determined how many times the same radial artery can be cannulated without complications. A total of 812 patients (502 men and 310 women) underwent angiography or angioplasty via the TRA between 1997 and 1999 at our institution with a total of 1,438 procedures. Sheaths were 5 (55%) or 6 Fr (45%). Dropout rates of 3.5% and 7.9% were found at the second TRA attempt in the men and the women, respectively. Of the 62 TRA failures, 56 (90%) were due to narrowing or occlusion of the radial artery after the previous TRA procedure. A third TRA procedure was possible in 90% of the men and 80% of the women. A fifth TRA procedure was possible in 70% of the men and 50% of the women. The dropout rates for TRA increased as successive punctures were performed. This was primarily due to vessel narrowing and occlusion occurring as a function of multiple punctures.

Aged↗
PubMed2001

Clinical characteristics of acute pulmonary thromboembolism in Japan: results of a multicenter registry in the Japanese Society of Pulmonary Embolism Research.

BACKGROUND: Although the incidence of acute pulmonary thromboembolism (APTE) has been increasing in Japan, patient characteristics, management strategies, and outcome have not yet been assessed in large series. HYPOTHESIS: The present study was designed to investigate the current status of APTE in Japan. METHODS: Of a total of 533 registry patients with pulmonary thromboembolism, 309 with APTE were analyzed with respect to clinical symptoms and signs, predisposing factors, diagnostic procedures, estimation of deep venous thrombosis, treatment, and clinical course. RESULTS: Main risk factors were recent major surgery, cancer, prolonged immobilization, and obesity; only a few patients had coagulopathy and 36% were in cardiogenic shock at presentation. The majority of registry patients underwent lung scans or pulmonary angiography; 30% were diagnosed only by lung scanning. Venous ultrasonography was used in only 34 patients, while 188 patients underwent at least one diagnostic procedure for deep venous thrombosis. Thrombolysis was more frequently performed in patients with cardiogenic shock, and only a few patients received thromboembolectomy. In-hospital mortality rate was 14%. In patients with cardiogenic shock, the mortality rate was reduced by thrombolysis. The predictors of in-hospital mortality were male gender, cardiogenic shock, cancer, and prolonged immobilization. CONCLUSIONS: The patients in this registry had almost the same findings as those in Western patients, except for some points that had the possibility of demonstrating a difference between Westerners and Japanese in the development of APTE. These results can prove especially helpful in planning prospective, randomized trials that will clarify the impact of widely used treatment modalities on the outcome of patients with APTE.

Age Distribution↗
PubMed2001

Super high-dose intraarterial cisplatin infusion under percutaneous pelvic perfusion with extracorporeal chemofiltration for advanced uterine cervical carcinoma: I. Analysis for pharmacokinetics, tumor response, and toxicity of platinum.

The present study was designed to elucidate the clinical feasibility of a new intraarterial infusion system with an extracorporeal charcoal chemofiltration circuit, which is expected to achieve a super high-dose cisplatin pelvic perfusion with a limited systemic exposure to platinum. After inferior vena cava isolation was percutaneously achieved by balloon catheter technique, cisplatin (140-240 mg/m2) was administered by selective intrauterine arterial infusion, with inferior and superior gluteal arterial embolization. The platinum-containing blood was pumped through an extracorporeal charcoal chemofiltration circuit. Pharmacokinetics, tumor response, and toxicity of platinum under this system were studied in 14 patients with locally advanced uterine cervical carcinoma. Extracorporeal charcoal filters significantly (p < 0.05) reduced the prefilter area under concentration-time curve of plasma-free platinum by 86.7 +/- 5.2% at postfilter site and 76.3 +/- 6.6% at peripheral circulation, respectively. Although all adverse effects were mild under this system, tumor response and tissue platinum concentrations were augmented dose dependently with the administration of cisplatin. The extracorporeal chemofiltration system achieved a super high-dose cisplatin pelvic perfusion with the minimal adverse effects, allowing further cisplatin dose escalation with further augmented tumor response. This will contribute to the reduction in the extent of disease of locally advanced uterine cervical carcinoma.

Adenocarcinoma↗
PubMed2001

Super high-dose intraarterial cisplatin infusion under percutaneous pelvic perfusion with extracorporeal chemofiltration for advanced uterine cervical carcinoma: II. Its impact on clinical response and subsequent surgery.

The present pilot study was conducted to investigate the clinical efficacy of super high-dose intraarterial cisplatin infusion with percutaneous pelvic perfusion under extracorporeal chemofiltration (PPPEC) for locally advanced uterine cervical carcinoma. Cisplatin (140-240 mg/m2) was infused in uterine arteries in a neoadjuvant setting in 20 patients under the PPPEC system twice during a 2-week interval. Fourteen of 17 patients in whom reduction of the disease (tumor downstaging) was confirmed underwent radical surgery. Despite the tumor downstaging, the remaining three patients had poor PS and the other three showed insufficient stage regression. Clinical responses, histologic responses, and surgical review were studied. The rate of overall tumor response (complete response plus partial response), tumor downstaging, overall histologic response, and radical surgery performance after the second course of PPPEC were 95.0%, 85.0%, 95.0%, and 70.0%, respectively. Curative surgery, defined as negative carcinoma cells in surgical margins, was achieved in 85.7% of the cases, whereas the rate of complete surgery defined as negative carcinoma cells both in surgical margins and regional lymph nodes was 42.9%. With 42 months of median follow-up time, 3 of the 14 surgical patients died of the original disease, and the remaining 9 patients are in recurrence-free survival, whereas 2 patients are alive with disease. PPPEC achieved a high frequency of rapid tumor downstaging of locally advanced uterine cervical carcinoma without severe adverse effects and resulted in the favorable performance of the subsequent radical surgery and prognosis.

Adenocarcinoma↗
PubMed2001

Diagnostic value of pulsed Doppler echocardiography in acute pulmonary thromboembolism--comparison with pulmonary angiography and pulmonary artery pressure.

The ratio of acceleration time to right ventricular ejection time (AcT/RVET) can be derived from the blood flow patterns recorded by pulsed wave Doppler echocardiography. In chronic cor pulmonale, AcT/RVET negatively correlates with pulmonary artery pressure (PAP). The present study evaluated the diagnostic value of AcT/RVET by comparing this variable with indices derived from pulmonary angiography (PAG) and PAP in 16 patients with acute pulmonary thromboembolism (APTE). AcT/RVET, PAP, and PAG severity indices (Miller index (MI) and UPET objective angiographic index (UI)) were measured during the acute phase on admission and the chronic phase after treatment. In the acute phase, AcT/RVET correlated with mean PAP (mPAP) (r=-0.68, p<0.05) and total pulmonary resistance (TPR) (r=-0.66, p<0.05), but not with MI or UI. During the chronic phase, AcT/RVET did not correlate with mPAP or TPR, but with both PAG indices (MI: r=0.76, p<0.05, UI: r=0.65, p<0.05). Before treatment of the APTE, AcT/RVET remained at low levels and could be used as an index of pulmonary hypertension. After treatment, however, following improvement of PAP, AcT/RVET was not useful for evaluating PAP, but might serve as an index for evaluating the volume of residual thrombi.

Acute Disease↗
PubMed2001

Successful removal of a left main coronary artery thrombus induced by vasospasm to the aorta [correction of vasospasm of the aorta] after the injection of contrast medium.

A 51-year-old woman with acute myocardial infarction underwent emergency coronary angiography. The patient had an episode of idiopathic thrombocytopenic purpura, and underwent splenectomy at the age of 36. On admission, platelet count in the peripheral blood was 43.2x10(4)/microl. During the initial emergency left coronary angiography, a thrombus was detected in the left main trunk. The thrombus was drawn back to the orifice of the left coronary artery, and finally disappeared into the aorta by injecting contrast media. After the thrombus disappeared, no stenotic lesion was detected in the left coronary artery. One month later, when acetylcholine-provocation coronary angiography was performed, marked vasospasm was detected in the left coronary arteries. Coronary thrombosis in the patient might have been induced by a coronary spasm, and the presence of thrombocytosis might also have affected the development of a coronary thrombus. However, it was spontaneously drawn back to the aorta by back flow of contrast media, which was injected via the entrance of the left coronary artery. A case of acute myocardial infarction whose thrombus occluded the left main coronary artery and was removed at first injection of contrast media is presented.

Aorta↗
PubMed2001

Sesamolin from sesame seed inhibits proliferation by inducing apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to sesamolin, a component of sesame seed led to both growth inhibition and the induction of apoptosis. Morphological change showing apoptotic bodies was observed in the cells treated with sesamolin. The fragmentation of DNA by sesamolin to oligonucleosomal-sized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. These findings suggest that growth inhibition of Molt 4B cells by sesamolin results from the induction of apoptosis in the cells.

Antineoplastic Agents↗
PubMed2001

Sesaminol from sesame seed induces apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to sesaminol, a component of sesame oil led to both growth inhibition and the induction of apoptosis. Morphological change showing apoptotic bodies was observed in the cells treated with sesaminol. The fragmentation of DNA by sesaminol to oligonucleosomal-sized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. These findings suggest that growth inhibition of Molt 4B cells by sesaminol results from the induction of apoptosis in the cells.

Apoptosis↗
PubMed2000

Left ventricular mass and global function in essential hypertension after antihypertensive therapy.

This study compares left ventricular global function in 55 patients (25 with hypertrophy and 30 without hypertrophy) with essential hypertension, whose blood pressure had been stable for longer than 1 year, with that in 35 healthy subjects. Left ventricular global function was calculated using the echocardiographic Doppler index as described by Tei et al. (Tei index). No significant differences were observed in echocardiographic left ventricular systolic function between the three groups. Left ventricular global function differed significantly between the three groups, however, suggesting impaired left ventricular global function even in the absence of left ventricular hypertrophy. Similar changes were observed in the ratio of peak velocity of atrial systole to peak velocity of early diastole during left ventricular inflow waveform (A/E), indicating that this disorder mainly reflects impaired left ventricular diastolic function. Unlike A/E, the Tei index is not affected by increasing age, and, therefore, is appropriate for evaluating left ventricular global function in hypertensive patients, most of whom are middle-aged or older. This index may be useful for determining treatment strategy and evaluating treatment effects.

Adrenergic beta-Antagonists↗
PubMed2000

[Correlation of DNA copy number changes to malignancy in oral squamous cell carcinomas by comparative genomic hybridization].

To compare clinical and histopathological findings to tumor DNA copy number changes, comparative genomic hybridization (CGH) was performed on 18 primary oral squamous cell carcinomas. Copy number increases were most frequently observed on 8q, 3q, 13q, 11p, and 11q, while copy number decreases most frequently on 10q, 1p, 18q, 9p, and 19q. Copy number changes in relationship to WHO grading were examined with the result that DNA copy number increase on chromosome 6p23-25 was characteristically observed in the groups of Grade II and Grade III, and DNA copy number decreases on chromosomes 9p21 and 11p11-13 were observed in the same groups. Furthermore, comparison of DNA copy number changes to TNM classification indicated that the decreases on chromosomes 1p36 and 10q25-26 might be related to tumor progression. Moreover, the relationship of DNA amplification or deletion to metastasis was investigated. It was found that the majority of the metastasis-positive tumors showed increases on 3q26 and 17q12-21 and showed decreases on chromosome 18q21. The data suggested that these DNA copy number changes on each chromosome in the three categories might be associated with tumor cell differentiation, tumor size, and lymph node metastasis.

Adult↗
PubMed2000

Cardiac function in dialysis patients evaluated by Doppler echocardiography and its relation to intradialytic hypotension: a new index combining systolic and diastolic function.

AIM, PATIENTS AND METHODS: Cardiac function of 40 patients on maintenance dialysis was examined using a new Doppler index combining systolic and diastolic function. Immediately before dialysis, ultrasonic pulsed Doppler was used to measure right and left ventricular inflow and outflow waveforms. The sum of the isovolumetric contraction time (ICT) and isovolumetric relaxation time (IRT) was calculated by subtracting the ejection time from the interval between the end of an inflow waveform and the start of the next inflow waveform. The new index was obtained by dividing the sum of the two isovolumetric times by the ejection time. Cardiac function was evaluated in dialysis patients and healthy controls using new indices of the right and left heart systems. RESULT: Indices of the right and left heart systems in dialysis patients were significantly higher than those in healthy controls. With respect to hypotension during dialysis, patients were divided into two groups, a group with decreased blood pressure (group A: 27 patients) and a group with normal blood pressure (group B: 13 patients). Only the left heart system index in group A was significantly higher. There were no significant differences in other M-mode Doppler indices between the two groups. CONCLUSION: The new index was a more sensitive evaluator of cardiac function and predictor of hypotension during dialysis compared to standard echocardiographic indices.

Adult↗
PubMed2000

Sesamin and episesamin induce apoptosis in human lymphoid leukemia Molt 4B cells.

The exposure of human lymphoid leukemia Molt 4B cells to sesamin and episesamin which were isolated from unroasted sesame seed oil and identified by MS, and 1H and 13C-NMR, led to both growth inhibition and the induction of programmed cell death (apoptosis). Morphological change showing apoptotic bodies was observed in the Molt 4B cells treated with sesamin and episesamin. The fragmentations by sesamin and episesamin of DNA to oligonucleosomal-sized fragments that are characteristics of apoptosis were observed to be concentration-dependent, respectively. Moreover, the amount of the DNA fragments in the sesamin-treated cells was increased from 2 days, while that in the episesamin-treated cells was elevated at 3 days after addition of the compounds. These findings suggest that growth inhibitions by sesamin and episesamin of Molt 4B cells result from the induction of apoptosis in the cells.

Antineoplastic Agents↗
PubMed1999

Serial changes in negative T wave on electrocardiogram in acute pulmonary thromboembolism.

A negative T wave is frequently observed in precordial ECG leads in patients with acute pulmonary thromboembolism. We investigated the clinical significance of negative T wave in 15 patients with acute pulmonary thromboembolism who were treated with thrombolytic agents by measuring the mean pulmonary artery pressure and ratio of right to left ventricular end-diastolic diameter using echocardiography and ECG. The study included only patients with massive acute pulmonary thromboembolism of a mean age of 65+/-9.7 years (+/-SD). A negative T wave was observed on admission in 10 patients but was later detected in 14 of the 15 patients. The mean amplitude of the negative T wave increased within 1 week then decreased after thrombolytic treatment. The peak negative amplitude of the T wave was observed from 1 to 7 days (mean, 2.6+/-1.8 days) and disappeared afterwards. During this period, improvements in both the mean pulmonary artery pressure (37.8+/-11.2 to 19.1+/-6.7 mmHg) and the ratio of right to left ventricular end-diastolic diameter (0.97+/-0.16 to 0.51+/-0.13) were noted in all patients. Our results suggest that an increase in the amplitude of negative T wave in precordial leads after thrombolytic therapy in patients with massive acute pulmonary thromboembolism reflects improvement in cardiopulmonary hemodynamics.

Aged↗
PubMed1999

Histamine H1 receptor and reactivity of the nasal mucosa in sensitized guinea pigs.

OBJECTIVE: Nasal Hypersensitivity to histamine is higher in allergic patients than that in normal control, suggesting that affinity and/or density of H1 receptors in nasal mucosa may be increased in patients with allergic rhinitis. The purpose in this study is to examine the correlation between the hyperresponsiveness and number of histamine H1 receptors in guinea pig nasal mucosa. METHODS: Guinea pigs were sensitized by DNP-Ascaris antigen. To block histamine H1 receptors, ketotifen was used and the number of receptors was counted by receptor binding assay technique. These data were compared with nasal airway volume (VOL) assessed by acoustic rhinometry of the same animals to know whether the number of H1 receptors is correlated to the nasal responsiveness to the antigen, or not. Eighty animals were divided into five groups which are composed of nonsensitized and sensitized group pretreated with saline, 0.1, 1.0 and 10 mg/kg of ketotifen, respectively. RESULTS: The number of H1 receptors (Bmax) was significantly increased in sensitized group compared with that in control. It decreased dose dependently by pretreatment of ketotifen. The percent change of VOL showed - 31.1 +/- 4.1% at 10 min and - 42.9 +/- 4.1% at 30 min after antigen challenge in sensitized animals. This was dose dependently inhibited by ketotifen. There was a highly inverse correlation between VOL and Bmax (r = -0.708, P< 0.0001). CONCLUSION: These results suggest that sensitization increases the number of histamine H1 receptor, and that increased number of H1 receptor in nasal mucosa in sensitized guinea pigs may be one of the causes of nasal hyperresponsiveness to antigen.

Administration, Oral↗
PubMed1999

Simultaneous assessment of right ventricular function and hypertrophy by Tc-99m MIBI.

PURPOSE: Tc-99m MIBI allows the simultaneous performance of cardiac blood pool scintigraphy and myocardial SPECT. The authors performed studies to determine whether right ventricular function and hypertrophy can be evaluated simultaneously using Tc-99m MIBI in patients with right heart disease. METHODS: Using right heart catheterization, several parameters of pulmonary circulation were measured, including right ventricular ejection fraction, in 23 patients with chronic pulmonary disease and pulmonary vascular disease. Within 1 week, right heart blood pool scintigraphy was performed using the first-pass method using Tc-99m MIBI. The right ventricular ejection fraction calculated from right heart blood pool scintigraphy was compared with that measured using right heart catheterization. Myocardial SPECT was performed 1 hour after right heart blood pool scintigraphy. On the short axis images, which allowed optimal visualization of the right ventricle, the right and left ventricular free walls were established as regions of interest. Myocardial wall counts were determined. The right ventricular uptake: left ventricular uptake ratio was calculated to study the relation of that ratio to mean pulmonary artery pressure and total pulmonary resistance. RESULTS: A significant correlation was observed between the right ventricular ejection fraction calculated on right heart catheterization and that calculated on right heart blood pool scintigraphy. The right ventricular uptake:left ventricular uptake ratio correlated positively with pulmonary artery pressure and total pulmonary resistance. CONCLUSION: These results suggest that Tc-99m MIBI allows simultaneous noninvasive evaluation of cardiac function and structure, which previously was considered impossible in patients with right heart disease.

Female↗
PubMed1999

EMG activity of the muscles of the neck and forelimbs during different forms of locomotion.

We recorded the electromyographic (EMG) activity of 7 skeletal muscles in the forequarters and 1 in the hindquarters of 6 Thoroughbred horses during overground walking, swimming in a circular pool, and walking and trotting in a water treadmill. Bipolar fine wire electrodes were inserted into the muscles and the EMG signals were recorded using a telemetric system. The splenius exhibited tonic EMG activity during swimming. The brachiocephalicus showed its highest intensity during swimming followed by the walk and trot in the water treadmill and then walking overground. The triceps brachii caput longum had a similar activity pattern to the brachiocephalicus. The brachialis showed only weak EMG activity in all 3 types of locomotion. The extensor digitorum communis had higher intensity of EMG activity in the walk in the water treadmill than in other kinds of locomotion. The flexor digitorum profundus exhibited the most intense EMG activity during swimming. These results indicated that swimming evoked strong EMG activity in the antigravity muscles in spite of reduced gravitational force. Walking in the water treadmill may require more intensified EMG activity of the forelimb than the trot in the same treadmill.

Animals↗