Biomedical subjects

H Etani

Publications and source records attributed to H Etani.

At least 19 recordsLinked to original sources

PubMed2000

Indium-111 platelet scintigraphy in a patient with chronic disseminated intravascular coagulation.

The authors describe a relation between the in vivo localized consumption of In-111 platelets and results of laboratory tests in a 82-year-old man with an aortic graft prosthesis who had chronic disseminated intravascular coagulation. In-111 platelets accumulated markedly over the abdominal aortic graft with a shortened platelet survival time and reflected changes in hematologic studies, which showed low platelet counts and a high concentration of fibrinogen degradation products in the plasma. If a strong clinical likelihood of local disseminated intravascular coagulation exists, then In-111 platelets may be valuable in localizing the focus of platelet consumption.

Aged↗

PubMed2000

Noninvasive measurement of cerebral blood flow with (99m)Tc-hexamethylpropyleneamine oxime single-photon emission computed tomography and 1-point venous blood sampling.

BACKGROUND AND PURPOSE: The arterial and venous blood concentration of technetium 99m-labeled hexamethylpropyleneamine oxime ((99m)Tc-HMPAO) reaches an equilibration more rapidly than other CBF tracers. We hypothesized that (99m)Tc radioactivity of a venous sample at equilibrium, which is similar to that of an arterial sample, would allow estimation of the integrated input function for the clinical measurement of CBF by use of single-photon emission CT. METHODS: In 53 patients with stable cerebrovascular disease, the radioactivity of a venous sample 5 minutes after injection of (99m)Tc-HMPAO was correlated with 5-minute arterial blood radioactivity and the first 5 minutes of the integrated arterial curves of the lipophilic tracer. The measured CBF values were compared with those of xenon 133. RESULTS: The radioactivity of 5-minute venous blood was almost equivalent to that of 5-minute arterial blood (r(2) = 0.987; y = 0.993x + 1.63; P : <0.0001). The correlation between the venous blood radioactivity and the integrated arterial lipophilic fraction was excellent (r(2) = 0.935, P : <0.0001). A strong correlation was obtained between (99m)Tc-HMPAO and (133)Xe CBF values (r(2) = 0.825, P : <0.0001). CBF values were reproducible (coefficient of variation, 8.6%). CONCLUSIONS: This approach is fast, simple, and an alternative to continuous blood sampling in clinical quantitative (99m)Tc-HMPAO CBF studies.

Arteries↗

PubMed2000

[Progression of silent cerebral infarction in Japanese: a hospital-based study].

Little is known about the risk factors for progression of silent cerebral infarction (SCI). We evaluated the 5-year change in high signal intensity on T2-weighted MR images of the brain in 50 asymptomatic patients with SCI. SCI progression was evaluated by the sum of the high intensity score (HIS) and the number of new lesions found on reexamination. Progression of SCI was seen in 19 patients (38%) on the 5-year follow-up examination. The baseline HIS in the whole brain was 8.02 +/- 6.93 and the follow-up HIS was 8.7 +/- 7.16 (p < 0.001). SCI progression was frequently seen in the corona radiata (p < 0.02 or < 0.05) or posterior periventricular white matter (p < 0.05). Patients with poor control of hypertension (> 160/95 mmHg) have a higher prevalence of SCI progression (9/12 (75%) vs. 10/38 (26.3%); OR = 8.4, p < 0.005) than the patients with effective control of BP (< or = 160/95 mmHg). The progression group showed a significantly higher baseline-HIS in the whole brain than the nonprogressing group (9.7 +/- 5.6 vs. 7 +/- 7.5; p < 0.05). Neither age percentages of alcohol drinkers, male sex, current smokers, hypertensives, hyperuricemia, hypercholesterolemia, diabetes, obesity, left ventricular hypertrophy, ischemic heart disease, nor differences in the controls of diabetes and hypercholesterolemia during the study were different between the progressing and the nonprogressing groups. Our data showed that poor control of high blood pressure and the degree of T2 high intensity in the baseline were strong predictors of SCI progression.

Aged↗

PubMed1997

The reproducibility of color Doppler duplex sonography in the measurement of renal arterial blood velocity.

In this study, the reproducibility of color Doppler duplex sonography for repeated measurements of renal blood flow was evaluated in 14 healthy subjects. We examined the reproducibility for different examiners and different time intervals between the examinations. Doppler frequency sonograms were analyzed with several parameters, and statistical evaluation was performed by calculating both the correlation coefficient (r) and coefficient of variation (CV). Peak systolic velocity (S), early diastolic velocity (D1) and mean velocity (MV) showed good reproducibility (r = 0.902-0.992, CV = 2.15-8.16%). On the other hand, end-diastolic velocity (D2), acceleration time (AT) and acceleration index (AI) showed poor reproducibility. We conclude that the reproducibility of this method is acceptable for repeated measurements of renal blood velocity, using suitable parameters S, D1 and MV.

Adult↗

PubMed1996

Effect of transcranial Doppler intensity on successful recording in Japanese patients.

The major limitation of transcranial Doppler sonography (TCD) is the failure to obtain data for all patients. The purpose of this study was to determine in detail the effect of increasing ultrasonic acoustic intensity on the rate of successful recording of intracranial blood velocity signals. The study was performed in 239 Japanese patients using a 2-MHz range-gated, pulsed-wave TCD. The middle cerebral artery flow signals were recorded at 76, 152, 228, 304, 380, 456 and 532 mW/cm2 and the results analyzed by age, gender and intensity. The rate of successful recording showed significant increase with the ultrasonic intensity in both genders (45.7% at 76 mW/cm2 vs. 81.1% at 532 mW/cm2 in males and 29.5% vs. 60.7% in females). However, recording was only successful in 54% of aged (50-89 gamma) female patients at the highest ultrasonic intensity used. It should be possible to significantly increase TCD usefulness in an aging Japanese population by further increasing TCD acoustic intensity within safety limitation.

Adult↗

PubMed1994

[Therapeutic effect of lisuride maleate on post-stroke depression].

Twenty post-stroke depressive patients who obtained more than 11 points on Self-Rating Questionnaire for Depression, were treated with 0.075 mg/day lisuride maleate for 12 weeks. The drug effect on depression was evaluated quantitatively by the Hamilton Rating Scale for Depression. The relationships between brain CT or MRI and SRQ-D score were investigated in 24 subjects. More than 80% of post-stroke depressive patients improved after lisuride maleate treatment for 8 or 12 weeks. In particular, depressed mood, hypobulia, sleep disturbance, anxiety, etc. were significantly improved compared to the baseline condition. As for the relationships with CT and/or MRI findings, the group with moderate to severe brain atrophy had a significantly higher grade of depressive state than those without.

Aged↗

PubMed1993

Rate of successful recording of blood flow signals in the middle cerebral artery using transcranial Doppler sonography.

BACKGROUND AND PURPOSE: To assess the usefulness of transcranial Doppler sonography, we investigated the rate of blood flow signal recording failure in the middle cerebral artery in Japanese subjects. Furthermore, we studied the effect of increased emitted power on the rate of successful recording in some of the patients in whom recording failure had been detected at the standard transducer power of 100 mW/cm2. METHODS: To evaluate the rate of successful recording, we measured blood flow signals in 597 patients (age range, 16 to 89 years) for screening of cerebrovascular disease by using a 2-MHz range-gated, pulsed-wave Doppler instrument at the standard transducer power. In 18 elderly patients with recording failure at the standard power, we assessed the effect of increased emitted power of 400 mW/cm2 on flow signal recording. RESULTS: Blood flow signals were recorded in 920 (77.1%) of the 1194 middle cerebral arteries of the 597 patients studied. The rate of successful recording of bilateral middle cerebral artery flow signals (70.9%; 423 of 597 patients) decreased with age, especially in females (17.0% in women aged 70 years or older). In 12 of 18 elderly patients with recording failure at the standard power, blood flow signals could be detected at the increased emitted power of 400 mW/cm2. CONCLUSIONS: The rate of successful recording of blood flow signals in Japanese subjects decreases with advancing age, especially in females. Increasing the emitted power markedly improves the successful recording rate.

Adolescent↗

PubMed1992

[Assessment of the rate of successful transcranial Doppler recording through the temporal windows in Japanese with special reference to aging and sex].

Transcranial Doppler method (TCD), newly developed in 1982, is ultrasound technology that measures physiologic parameters of blood flow in the major intracranial arteries. A major limitation of TCD is that, in some individuals, satisfactory recording is not possible, especially through the temporal windows. The purpose of the present study is to assess the rate of successful recording in TCD through the temporal ultrasonic windows in Japanese with special reference to aging and sex. In 423 Japanese (244 males and 179 females) aged from 25 to 93 years, measurement of blood flow velocity in basal cerebral arteries was performed by transcranial Doppler velocimeter with a 2 MHz pulsed wave Doppler probe. The signal was successfully recorded in 299 of 423 Japanese (71%). In Japanese males, successful measurement was more frequent (206/244; 84%) than in Japanese females (93/179; 52%). The rate of successful recording was evaluated in every decade from the twenties to the eighties, and it was found to decrease significantly according to age (100%, 94%, 91%, 74%, 66%, 67%, and 46%, respectively). In females, it significantly decreased in those older than 50 years old (100%, 100%, 93%, 61%, 36% 43%, and 27%, respectively), but not in males (100%, 88%, 89%, 81%, 88%, 83%, and 69%, respectively). These findings suggest that this noninvasive method has clinical usefulness for evaluating intracranial circulation but has limitation for assessing the intracranial lesions of elderly Japanese women.

Adult↗

PubMed1992

[Platelet accumulation in abdominal aortic aneurysms and the effect of antiplatelet drugs: assessment by indium platelet scintigraphy].

A dual tracer technique using 111In labeled platelets and 99mTc labeled human serum albumin was applied to evaluate the in vivo thrombogenicity in 12 cases with abdominal aortic aneurysm (AAA) and the effect of antiplatelet drug on the thrombogenicity. The magnitude of platelet accumulation at AAA was expressed as the ratio of radioactivity of 111In platelets on the vascular wall to those in the blood pool (PAI; platelet accumulation index). Of the 12 patients with AAA, 11 had positive studies on baseline imaging and 1 had equivocally positive image. The PAI value (Mean +/- SD) over the AAA was 53.8 +/- 34.1% as compared to -8.6 +/- 4.4% in the control group (p less than 0.01). Seven patients with an AAA and positive baseline images were restudied during platelet active drug with 325 mg of aspirin. During treatment with aspirin, of 7 patients, 5 had positive images, of which 3 were decreased and others unchanged compared to baseline studies, 1 equivocally positive one and one negative one. The PAI value during treatment (21.9 +/- 18.6%) was significantly decreased compared to those in baseline study (52.1 +/- 23.9%). Our results suggest that the method used for platelet imaging in the present study may be useful for studying the in vivo thrombogenicity and the effect of platelet active drugs in AAA.

Aged↗

PubMed1990

A validation study on the reproducibility of transcranial Doppler velocimetry.

The transcranial Doppler method for the measurement of intracranial arterial blood flow velocity is a useful noninvasive technique with a number of applications. The present study validated the reproducibility of this method for repeated measurements of flow velocity in the middle cerebral and basilar arteries. Fifteen healthy volunteers were studied. Measurements were made twice by one examiner and once by another in a single day and again by the first examiner on another day. The reproducibility was evaluated by calculating the correlation coefficient (r) and the coefficient of variation (CV) of the difference between the values obtained from each pair of measurements. Although depending on the examiner, the time interval between the examinations and the vessels studied some differences were noted in the reproducibility, both the r (0.69-0.95) and CV (6.7%-19.5%) values in the whole study were good enough to warrant the applicability of this method for the repeated measurements of the intracranial arterial blood flow velocity in future studies.

Cerebral Arteries↗

PubMed1990

[Functional alterations of human platelets following 111In labeling with different ligands and incubation media].

We studied the effects of various 111In-water soluble chelates and incubation media on labeling efficiency of platelets and in vitro platelet aggregability. High labeling efficiency of platelets in ACD-saline was achieved with 111In-oxine sulfate, 111In-tropolone and 111In-MPO (2-mercaptopyridine-N-oxide). In the condition with 4.8 x 10(6)/mm3 platelets in ACD-plasma, 111In-oxine-sulfate had low labeling efficiency and inconsistent labeling, while 111In-tropolone and 111In-MPO had high labeling efficiency. In vitro platelet aggregability (ADP 2 microM) was reduced when platelets were labeled in the absence of plasma. However, there was no significant difference in platelet aggregability among 111In-platelets labeled by three different chelates. In conclusion, to maintain aggregation activity of the platelets with relatively high labeling efficiency, the best result was obtained by using MPO or tropolone chelate in plasma at 4.8 x 10(6)/microliters platelet concentration.

Adult↗

PubMed1990

A new apparatus for brain imaging: four-head rotating gamma camera single-photon emission computed tomograph.

The development of a new rotating gamma camera SPECT device for imaging the brain was undertaken with the objective of achieving the highest full volume imaging spatial and temporal resolution performance. For this purpose, four rectangular gamma camera detectors were arranged as close to the head as possible, and united in a block to insure detector head registration and alignment as well as to enable rotation stability at high speeds. Phantom and clinical studies performed demonstrated 42 sequential, 4-mm thick transaxial images acquired in one scan and with sufficient volume to permit the entire cerebrum and cerebellum to be imaged with high sensitivity. The central field of view reconstructed spatial resolution measured 7.0 mm full width of half maximum utilizing the high-resolution collimator, and tomographic images of arbitrary planes including sagittal and coronal demonstrated equally high resolution. The high sensitivity and high speed rotational acquisition capability of the device permits dynamic SPECT studies to be carried out in the analysis of rapidly varying radiotracer concentrations.

Brain↗

PubMed1989

[Assessment of reproducibility of transcranial Doppler velocimetry].

In recent years, transcranial Doppler velocimetry has been widely used as a noninvasive method for measurement of blood flow velocity in basal cerebral arteries. As for the reproducibility of this method, however, there have been only few reports so far. In the present study, we attempted to evaluate the reproducibility of this method by changing the examiners and the timing of the examination. Fifteen healthy volunteers were investigated by using a pulsed wave Doppler ultrasound device with a 2 MHz transducer. Both peak and mean spatial frequencies calculated from the frequency spectrum of the Doppler signals from the middle cerebral artery (MCA) and the basilar artery (BA) were used as blood flow parameters for assessing the reproducibility. The arterial blood pressure and the end-tidal carbon dioxide partial pressure (PECO2) were also monitored during the ultrasonic examinations. The intra- and inter-observer reproducibilities were evaluated by obtaining the coefficient of variation (CV) of the differences and/or analyzing the correlation between the values from the two measurements by the same examiner and by two separate examiners, respectively. The intraobserver reproducibility in separate days was also evaluated. Both in the mean arterial blood pressure and in PECO2, no significant changes were observed between the two measurements in each subjects. In the present examination, the CV and r values ranged from 6.7 to 19.5% and from 0.69 to 0.95, respectively, showing good reproducibility of the transcranial Doppler method for measurement of blood flow velocity, though some differences were observed as follows. The intraobserver reproducibility was better than the interobserver reproducibility.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

Levallorphan and dynorphin improve motor dysfunction in Mongolian gerbils with unilateral carotid occlusion: the first application of the inclined plane method in the experimental cerebral ischemia.

Levallorphan and dynorphin were effective on the motor dysfunction in the gerbil model of unilateral cerebral ischemia. The effect of opioids, levallorphan (mixed agonist-antagonist), dynorphin (kappa-receptor agonist) and naloxone (mu-receptor antagonist), on neurological impairment was evaluated using the unilateral cerebral ischemia model of gerbil. Motor function was evaluated quantitatively by using the inclined plane method. Both levallorphan-treated group and dynorphin-treated group showed a significant improvement of the motor dysfunction compared with saline-control group. On the other hand, naloxone-treated group did not differ from saline-control group. The beneficial effect of these opioids on motor dysfunction might be mediated by the kappa-opioid receptor. This study also showed the potential usefulness of the inclined plane method for the investigation on the cerebral ischemia.

Animals↗

PubMed1988

Carbondioxide reactivity of the blood flow in human basilar artery estimated by the transcranial Doppler method in normal men: a comparison with that of the middle cerebral artery.

Using the transcranial Doppler technique, the carbondioxide reactivity of the blood flow velocity in the human basilar artery (BA) was investigated in healthy volunteers for comparison with that in the middle cerebral artery (MCA). An exponential curve with an exponent of 0.044 mmHg-1 was found to be a good fit to the BA data and 0.040 mmHg-1 to the MCA data, respectively. While the response of both arteries showed a good correlation to the end-tidal carbondioxide partial pressure (PETCO2), there was no significant difference observed between the carbondioxide (CO2) reactivity of each artery. In both arteries, the end-diastolic flow velocity decreased significantly with the reduction of PETCO2, which may represent the increasing resistance of cerebral microvasculature in hypocapnia. Because of the reliability and noninvasiveness of this method, this normal value should be quite helpful for the bed-side evaluation of an altered CO2 response in the patients with cerebrovascular disease.

Adult↗

PubMed1988

Efficacy of echo-Doppler examination for the evaluation of renovascular disease.

The accuracy of the diagnosis of renal artery stenosis using noninvasive echo-Doppler velocimetry was compared with that of angiography in 40 renal arteries. The duplex-Doppler signals were detected through the muscle of the back (the translumbar approach). Renal artery stenosis was diagnosed by three objectively defined Doppler parameters, the acceleration index (AI), the acceleration time (AT), and the acceleration time ratio (ATR). The normal range obtained on 11 control subjects was defined as AI greater than or equal to 3.78, AT less than or equal to 0.07 s, and ATR less than or equal to 1.35. High technological success (98%) was obtained using the translumbar approach. In comparison with angiography (cases of significant stenosis), the accuracy of the echo-Doppler method using the criteria of the AI was 95%, the sensitivity was 100%, and the specificity was 93%. This noninvasive method may be one of the most accurate screening methods for diagnosing significant renal artery stenosis.

Blood Flow Velocity↗

PubMed1988

Iodine-131-labeled fibronectin: potential agent for imaging atherosclerotic lesion and thrombus.

Fibronectin is known to interact with fibrin, collagen, etc. We have labeled fibronectin with 131I, and measured its accumulation in the deendothelialized lesion in the rabbit aorta to evaluate it as a candidate for imaging atherosclerotic lesions and thrombi. Accumulation of [131I] fibronectin in the deendothelialized lesion was apparent at 48 hr, and increased at 72 hr after injection of the agent. Our results indicate that radiolabeled fibronectin may be a useful tracer for imaging early atherosclerotic lesion and thrombus.

Animals↗

PubMed1987

A gamma camera system for atraumatic rCBF measurement using a new super high sensitivity collimator.

The purpose of this study is to develop a useful gamma camera system for atraumatic rCBF measurement by the 133Xe intravenous injection (i.v.) method. A super high sensitivity slant hole (SHS-SL) collimator was designed for this purpose. The gamma camera used with this collimator was able to move close to the patient's head and obtain satisfactory count rates (130 kcpm-178 kcpm in a hemisphere) with a low dosage (10 mCi) of 133Xe. To validate this rCBF measurement system three studies were carried out: a comparative evaluation was performed against the flow values with the intracarotid 133Xe injection (i.c.) method, reproducibility of flow values was assessed from two serial i.v. measurements, and flow values were compared with clinical severity of the patients. The comparative study showed good correlation in the hemispheric and regional values between the two methods; r values 0.98 and 0.64-0.93 for gray matter flow and 0.96 and 0.78-0.93 for initial slope index. In the reproducibility study, the variation coefficients in the hemispheric and regional values between the two serial measurements were 5.0% and 7.3%-14.2% for gray mater flow, 5.2% and 7.9%-12.9% for initial slope index. The reproducibility in this study was as good as those with the i.c. method reported previously. The hemispheric flow values from our gamma camera system correlated well with the clinical severity of cerebrovascular disease. These results show that the gamma camera system with the SHS-SL collimator is useful for atraumatic rCBF measurement.

Brain Ischemia↗