Search PubMed⌕ Search

Biomedical subjects

E Tsukamoto

Publications and source records attributed to E Tsukamoto.

At least 73 records · Page 4Linked to original sources
PubMed1995

[Imaging of infectious and inflammatory foci using 111In-DTPA-IgG].

We performed radionuclide scanning after intravenous administration of 80 MBq of 111In-labeled non-specific polyclonal human immunoglobulin G (111In-DTPA-IgG). Serial scintigrams were acquired at 6, 24, 48, and 72 hr after injection in 10 patients suspected of having inflammation and/or infection. In 5 patients, the results of scintigraphy were verified with intraoperative cultures or biopsy. The values were as follow: sensitivity: 100% (4/4); specificity 50% (3/6); accuracy: 70% (7/10); positive predictive value: 57.1% (4/7); and negative predictive value: 100% (3/3). The results indicate that 111In-DTPA-IgG scintigraphy is certainly a promising method for the detection of inflammation and/or infection.

Adult↗
PubMed1995

[Phase 3 multicenter clinical study of 111In-DTPA-D-octreotide (MP-1727) in patients with gastrointestinal hormone producing tumors].

A phase 3 multicenter clinical study was performed to investigate the efficacy, safety and usefulness of MP-1727, a novel tumor imaging agent which binds to somatostatin receptors, in 23 patients with gastrointestinal hormone producing tumor. The efficacy was graded effective or very effective in 16 cases (76.2%) out of 21 cases who could be evaluated. Positive predictive accuracy was 77.8% (7/9) for carcinoids, 100% (5/5) for gastrinomas and 40.0% (2/5) for insulinomas. In three cases, tumor lesions which had been unknown were detected by MP-1727 scintigraphy. The consistent ratio between scintigraphically positive sites and preinjection localizations was 82.0% (41/50 sites) in total. Although adverse drug reactions were observed in two cases, the safety was graded 'not problematic at all' in all of 23 cases. These results show that MP-1727 is a very useful radiopharmaceutical for detection and localization of gastrointestinal hormone producing tumors.

Adult↗
PubMed1994

Platelet-activating factor and antiphospholipid antibodies in subarachnoid haemorrhage.

The purpose of this study was to measure plasma platelet-activating factor (PAF) concentration, PAF-acetylhydrolase activities, anti-phospholipid antibody (aPLs) titers, and platelet function in patients with subarachnoid haemorrhage (SAH) and to assess the association of these variables with the development of cerebral vasospasm. Thirty-two patients with SAH due to ruptured cerebral aneurysm were studied. Plasma PAF concentration, PAF-acetylhydrolase activity, platelet count and aggregability, and plasma factor 4 (PF4) concentrations were measured regularly until approximately 2 weeks after SAH. aPLs, including lupus anticoagulant and anti-cardiolipin IgG and IgM were measured within 3 days after SAH. Plasma PAF concentration in patients with SAH showed the highest value on the occasion during 5 to 9 days after SAH. The concentrations were higher in patients with infarction due to vasospasm than in patients without cerebral infarction on any occasions after SAH. Plasma PAF-acetylhydrolase activities did not change in patients, regardless of the presence of cerebral infarction after SAH. Increased platelet consumption and aggregability and higher concentrations of PF 4 were detected in patients with cerebral infarction and not in patients without cerebral infarction. The patients with cerebral infarction due to cerebral vasospasm had aPLs more frequently than the control volunteers. Our findings indicate that increased plasma PAF and aPLs may contribute to the pathogenesis of cerebral vasospasm after SAH.

Adult↗
PubMed1994

In vivo kinetics of 99mTc labeled recombinant tissue plasminogen activator in rabbits.

Our previous studies demonstrated that 99mTc labeled recombinant tissue plasminogen activator (rt-PA) retained high affinity with fibrin in vitro but showed unexpectedly low uptake in fresh thrombi in vivo. The present study was performed to determine the in vivo kinetics of radiolabeled t-PA in the rabbit. Sequential images and blood samples after the intravenous administration of 99mTc labeled rt-PA in thrombus-bearing rabbits were taken. The radioactivity and immunological level of t-PA and PAI-1 in the solution eluted to each fraction by gel permeation chromatography were measured by means of a well scintillation counter and enzyme-linked immunosorbent assay (ELISA). Most of the radioactivity was eluted in the fraction (Fr. 7) of larger molecular weight than that (Fr. 9) of intact t-PA. The level of intact rt-PA was increased with a regimen involving the preadministration of cold rt-PA which was followed by the administration of hot rt-PA. The level of PAI-1 in plasma showed an increased rebound 15 minutes after the intravenous injection. These results suggest two possible reasons why rt-PA retains high affinity with fibrin in vitro, once radiolabeled, but was ineffective in delineating fresh thrombi with a gamma camera: 1) some plasma components such as PAI-1 combine with circulating radiolabeled rt-PA and form a larger molecule immediately and/or 2) radiolabeled rt-PA is modulated as a consequence of the radiolabeling and forms a larger molecule than intact rt-PA.

Animals↗
PubMed1993

Phase II study of Tc-99m MAG3 in patients with nephrourologic diseases.

Tc-99m-labeled mercaptoacetyltriglycine (Tc-99m MAG3) is a recently introduced radioagent that is excreted by tubular function. The aim of this study was to test Tc-99m MAG3 as an imaging agent for renal scintigraphy and renal plasma flow measurement. Image quality was tested with four different administered doses of Tc-99m MAG3, 100 MBq, 200 MBq, 300 MBq and 400 MBq, in four patients each. All administered doses except 100 MBq were sufficient for visible inspection of the nephrogram and drainage images; however, an administered dose higher than 300 MBq was necessary to maintain the quality of the blood perfusion image. The blood clearance with Tc-99m MAG3 or I-131 orthoiodohippurate (I-131 OIH) was calculated within the same day by the single blood sampling method. The blood clearance with Tc-99m MAG3 was 1.2-fold lower than with I-131 OIH, but correlated well (OIH = 91.34 +/- 0.932 MAG3, r = 0.953, P < 0.001). The blood clearance with Tc-99m MAG3 also correlated with the percentage of renal uptake estimated by the count-based gamma camera method at 1.5 to 2.5 minutes after injection (ERPF = -59.13% +/- 16.87% uptake, r = 0.845, P < 0.01). The mean labeling yield of Tc-99m MAG3 was 97%. None of the patients complained of side effects from Tc-99m MAG3. Tc-99m MAG3 is concluded to have good properties as a tubular radioagent for dynamic renal scintigraphy and renal plasma flow measurement.

Female↗
PubMed1993

Captopril renoscintigraphy with Tc-99m DTPA in patients with suspected renovascular hypertension. Prospective and retrospective evaluation.

Sensitivity and specificity of captopril renoscintigraphy (CRS) with Tc-99m DTPA has been analyzed in 41 cases, 16 with renovascular hypertension (RVH) and 25 with non-RVH. The sensitivity and specificity of the baseline study were 63% (10/16) and 63% (12/19), respectively, based on the split renal function study in which the lower limit of normal was assumed to be 42% of the total renal uptake. Captopril renoscintigraphy yielded 67% (12/18) sensitivity and 76% (19/25) specificity. The low specificity of CRS was due to the application of a prospective criterion of the captopril-induced reduction rate (CRR) of less than -20%, which was calculated from the renal uptake before and after captopril. When criteria of CRR less than -25% were used, the specificity of CRS was improved to 96%, but the sensitivity declined to 61%. Changes in the configuration of the renogram induced by captopril also had high specificity but low sensitivity. Renovascular hypertension was most likely when criteria for both CRR and the renogram were fulfilled. These criteria often were diagnostic in patients with bilateral renal artery stenosis that showed variable scintigraphic responses to captopril challenge. Captopril renoscintigraphy is a very specific means to evaluate RVH, but may have limitations in certain clinical situations such as poorly preserved function of the affected kidney, prior long-term administration of captopril, prior surgical manipulation of stenotic renal artery, and chronic renal parenchymal damage.

Adult↗
PubMed1993

Comparative study of renal scintigraphy with 99Tcm-mercaptoacetyltriglycine and 123I-orthoiodohippurate.

This study was undertaken to compare image quality, renal handling and plasma clearance of 99Tcm-mercaptoacetyltriglycine (99Tcm-MAG3) with those of 123I-orthoiodohippurate (123I-OIH). 99Tcm-MAG3 was prepared in-house using an instant kit vial and 123I-OIH was commercially available in a form already labelled. Both studies were undertaken in 20 patients with nephrourological disorders after intravenous (i.v.) injection of 300 MBq 99Tcm-MAG3 and 34 MBq 125I-OIH within the time interval of 3 to 4 days. 99Tcm-MAG3 was much superior to 123I-OIH in visualization of renal perfusion, renal parenchyma and urinary tract. The time parameters of the renogram, Tmax and T1/2 were significantly prolonged in 99Tcm-MAG3 compared to those for 123I-OIH (P < 0.05). Plasma clearance of 99Tcm-MAG3 was also slower than that of 123I-OIH but correlated well with that of 123I-OIH (r = 0.958, P < 0.01). The % renal uptake of 99Tcm-MAG3 per injected dose, which was calculated by the gamma camera method, also correlated well with effective renal plasma flow (ERPF) calculated by the single blood sampling method (r = 0.940, P < 0.01). The renal handling and plasma clearance of 99Tcm-MAG3 are not completely identical with those of 123I-OIH. However, 99Tcm-MAG3 has the clinical advantages of superior image quality, the feasibility of gamma camera measurement of quantitative renal uptake, and ready availability for routine clinical use.

Adult↗
PubMed1993

Technetium-99m-labeled recombinant tissue plasminogen activator for the imaging of emboli in vivo.

Tissue-type plasminogen activator (t-PA) effectively lyses active thrombus by direct action. Recombinant t-PA (rt-PA) was labeled with technetium-99m (99mTc) to investigate the in vivo binding to fibrin clots in a feline cerebral embolism model created by insertion of an artificial fibrin clot within the carotid artery. 99mTc-rt-PA administered intravenously provided clearer imaging of clots after priming with cold rt-PA, with uptake peaking 5-10 minutes after the injection. 99mTc-labeled human serum albumin was not retained at clot sites. Systemically administered 99mTc-rt-PA binds to fibrin clots within carotid arteries in our feline model. Our results suggest that the interaction of intrinsic plasminogen activator inhibitors with extrinsically administered rt-PA may regulate the demonstration of a clot, although the precise mechanism is unclear.

Animals↗
PubMed1993

[Phase II clinical study of 99mTc-MAG3].

Phase II clinical study of mercaptoacetylglycyl-glycylglycinate (99mTc) technetium (99mTc-MAG3), a new scintigraphic and renographic agent, was performed to evaluate its safety, clinical usefulness and optimal dosage at 5 institutions in total 88 patients with mild renal or urinary disorders. There was no case showed adverse reaction in patients studied and the administration of the agent was proved to be safe. The effectiveness of the agent was evaluated and revealed to be effective in all cases analyzed. A range of dosage 200-400 MBq was found to be optimal, from image quality and clinical information obtained. It is concluded that 99mTc-MAG3 is a safe and useful radiopharmaceutical for the diagnosis of renal dynamic function.

Adolescent↗
PubMed1993

[Role of 99mTc-labeled RBC SPECT in the diagnosis of hepatic hemangioma--comparison with US, CT and angiography].

The roles of planar imaging and SPECT with 99mTc-labeled RBC, US, Dynamic CT and angiography in the diagnosis of hepatic hemangioma were evaluated. The study group consisted of 18 patients with a total of 40 hemangiomas and 13 patients with a total of 21 non-hemangiomas. Among these patients, 5 patients with a total of 8 hemangiomas and 10 patients with a total of 14 non-hemangiomas were diagnosed by operation and biopsy. In all 40 hemangiomas, sensitivity for planar imaging was 35%, SPECT 50%, US 53%, Dynamic CT 82% and angiography 81%, respectively. When the tumor size was greater than 2.2 cm by SPECT and 2.8 cm by planar imaging, their sensitivity for both methods was 100%. Specificity for planar imaging was 100%, SPECT 95%, US 81%, Dynamic CT 100% and angiography 83%, respectively. One patient with hepatocellular carcinoma diagnosed by angiography showed increased uptake on SPECT. Because of the highest accuracy for SPECT in hemangioma greater than 2.0 cm, SPECT should be considered to be the method of choice for noninvasive diagnosis of hemangioma.

Adult↗
PubMed1992

Single photon emission computed tomography using 201Tl chloride in pulmonary nodules: comparison with 67Ga citrate and 99mTc-labeled hexamethylpropyleneamine-oxime.

A single photon emission computed tomography (SPECT) with 201Tl chloride (Tl-201) was carried out prospectively in 50 patients with pulmonary nodules and its diagnostic value was compared with those of 67Ga citrate (Ga-67) and 99mTc-labeled hexamethylpropyleneamine-oxime (Tc-99m-HMPAO). Tl-201 SPECT provided 88% (early)-91% (delayed) sensitivity, 85% (early and delayed) specificity and 87% (early)-89% (delayed) accuracy. The sensitivity of the Tl-201 planar image was 56 (early)-62% (delayed), which was significantly lower than that of SPECT. Delayed SPECT images at 2 hour postinjection were more preferable to disclose the malignant pulmonary nodule than early SPECT images at 15 minutes postinjection. The application of SPECT with Ga-67 failed to improve the sensitivity of planar imaging for malignant pulmonary nodules. Tc-99m-HMPAO was concentrated in 62% of 13 patients with malignant pulmonary nodules, which was slightly higher than Ga-67 in 54% of 28 patients. In an analysis of the histologic types of lung cancer, the sensitivity of Tl-201 was not significantly different in all types. On the other hand, Ga-67 was positive only in 25% of 12 patients with adenocarcinoma. A combination of SPECT and Tl-201 is the best choice among routine scintigraphic techniques for depicting malignant pulmonary nodules. The Tl-201 SPECT image may play a complementary role in the characterization of pulmonary nodules which are revealed on a plain radiograph and computed tomography.

Adult↗
PubMed1992

In vivo distribution of Tc-99m labeled recombinant tissue-type plasminogen activator in control and thrombus-bearing rats.

In vivo distribution of Tc-99m labeled recombinant tissue-type plasminogen activator (Tc-99m-rt-PA) was studied in control rats and thrombus-bearing rats. To compare fibrin binding in vivo with that in vitro, Tc-99m-rt-PA binding to fibrin gel in vitro was also imaged. Rapid blood clearance and accumulation into the liver and kidneys were observed in both control and thrombus-bearing rats. Accumulation in the stomach, which indicates instability of labeled rt-PA in vivo, was very low until two hours after injection. Tc-99m-rt-PA accumulation in the clots was higher than that in skeletal and heart muscles, although it was lower than in blood, liver, and kidneys. Administration of aprotinin, an antifibrinolytic agent, significantly prolonged clot accumulation of Tc-99m-rt-PA at 30 minutes after injection. These results suggest that fibrinolysis is responsible for the low rt-PA concentration in the clots. A scintigram of a thrombus-bearing rat demonstrated increased radioactivity at the clot forming site. On the other hand, Tc-99m-labeled human albumin, which was used as a control, was not accumulated in the clot. Tc-99m-rt-PA binding to fibrin gel in vitro was clearly imaged. By comparison, in vivo fibrin binding of Tc-99m-rt-PA was much lower than in vitro. The reasons for low thrombus uptake in vivo may be: 1. biochemical inactivation of extrinsically administered rt-PA by t-PA inhibitor. 2. fibrinolysis by rt-PA activated plasminogen. Overcoming these limitations will enable Tc-99m-rt-PA to reach the stage of clinical trials.

Animals↗
PubMed1991

Single photon emission computed tomography with Tc-99m-dimercaptosuccinic acid in patients with upper urinary tract infection and/or vesicoureteral reflux.

By means of Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy, an established method for assessing renal cortical damage, we evaluated the pick-up rate for renal defects (scars) by single photon computed tomography (SPECT) and planar images of 10 normal volunteers, and 58 patients (70 scintigrams) with upper urinary tract infections, most of whom had a history of vesicoureteral reflux (VUR). The positive study rate for renal defects depended on the severity of VUR. The overall positive rates for renal cortical defects obtained by DMSA SPECT imaging and DMSA planar imaging were 60% and 43%, respectively, and the difference between these was significant (p less than 0.005). The mean absolute individual renal uptake (/injected dose) at 2 hours post-injection was decreased in kidneys with defects detected by SPECT alone. The positive study rate for intravenous urography (IVU) depended on the grade of VUR and was 15% overall. DMSA SPECT imaging detects renal cortical defects at greater frequency than previously achieved.

Adolescent↗
PubMed1991

Tc-99m labeled tissue-type plasminogen activator: preparation, stability and preliminary imaging of thrombus-bearing rats.

Tissue-type plasminogen activator (t-PA) is a thrombolytic agent that directly binds to fibrin formed in clots. In terms of radiolabeling and nuclear imaging, t-PA has several advantages in Tc-99m labeling: it is stable in acidic solution at pH 3, which is suitable for labeling Tc-99m by a method of stannous reduction and blood disappearance after administration is rapid, which is desirable for imaging targets using short-lived radionuclides. Recombinant t-PA was labeled with Tc-99m by a method of stannous reduction without significant degradation of biochemical activity, over 95% of which was retained after the labeling procedure. Labeling efficiency in paper chromatography was over 98%. The moiety of hydrolyzed Tc-99m that was not eluted through the Sephadex column was estimated to be less than 10%. Tc-99m labeled t-PA, however, appeared to become unstable when diluted with normal saline. Nevertheless, in in vitro fibrin binding, Tc-99m labeled t-PA showed high affinity with fibrin: 80% of 100 ng/ml of Tc-99m t-PA bound to 10(-5) mol of the fibrinogen. Preliminary animal studies also showed a concentration of Tc-99m labeled t-PA at fresh thrombi formed in the inferior vena cava. Tc-99m labeled t-PA appears to have potential for thrombus imaging and the preparation of an instant kit.

Animals↗
PubMed1991

[Adrenocortical scintigraphy to evaluate incidental adrenal mass (incidentaloma) discovered on computed tomography].

To assess the nature of adrenal mass incidentally discovered on computed tomography, adrenocortical scintigraphy with I-131-6 beta-iodomethyl-19-norcholest-5(10)-en-3 beta-ol (I-131 Adosterol) in 29 patients was retrospectively reviewed. All patients had no clinical symptoms and biochemical evidence of adrenal hyperfunction. Six of them had extra-adrenal malignancy. Increased tracer uptake on the side of adrenal mass was observed in 13 patients (concordant group): cortical adenoma in 8, macronodular hyperplasia in 1, no growing tumor in 1, and no further examination in the remaining 3 patients. No cancer patients were included in the concordant group. Symmetric uptake was seen in 9 patients (symmetric group): 1 cortical adenoma and 1 ganglioneuroma, 6 no growing tumor (two of them had malignancy), and no further examination in 1 patient. Decreased uptake were shown in 7 patients (dis-concordant group): metastasis in 4, adrenal cyst in 2, and no growing tumor in 1. Adrenocortical scintigraphy was helpful in distinguishing benign functioning adrenal masses from non-functioning adrenal masses such as metastatic tumor and cyst.

Adenoma↗
PubMed1990

[Cystic papillary carcinoma of the thyroid--sonographic-pathologic correlation].

Ultrasonographic findings of 13 patients with cystic papillary carcinoma (CPC) of the thyroid gland were reviewed retrospectively correlating with pathologic findings. A 4-6 cm oval cystic structure with a 2-3 cm pedunculated projection of mass into the lumen was the characteristic sonographic findings of CPC. However, other sonographic findings of CPC simulated adenoma, nodular goiter or follicular carcinoma. Pathological investigation revealed that malignant cells tended more to be located in intracystic pedunculated mass and/or pericystic region than in the cyst wall. In most of the cases cyst walls were chiefly composed of granulomatous tissue with scattered malignant cells. These findings indicate that the needle biopsy should be done under ultrasonographic guidance to obtain sufficient material for accurate cytologic and/or pathologic diagnosis, thereby reducing the number of false negative cases.

Adult↗
PubMed1990

[Captopril-enhanced renography using 99mTc-DTPA in renovascular hypertensive patients].

Dynamic renal scintigraphy with 99mTc-DTPA before (baseline renography: BS-RG) and 1 hour after administration of 25 mg to 50 mg of captopril (captopril-enhanced renography: CP-RG) was performed in a selected series of 18 patients suspected of having renovascular hypertension. Final diagnosis was made by angiography and further clinical follow-up. Eight patients were considered as renovascular hypertension (RVH), 6 with bilateral renal artery stenosis (BRAS) and 2 with unilateral renal artery stenosis (URAS). The remaining 10 patients were non-renovascular (non-RVH). Two criteria were prospectively employed for evaluating positive response induced by captopril. Glomerular filtration rate (GFR) on BS-RG (GFRbase) and on CP-RG (GFRcap) was estimated by early (120-180 seconds) DTPA uptake by the kidney, and then captopril response rate (CRR) was calculated in the following: CRR = (GFRcap-GFRbase)/GFRbase X 100 (%). CP-RG was considered positive when it was less than 20%. Renogram shape was also independently evaluated. CP-RG was also considered positive when either a delay of time to peak activity of more than 5 min or conversion of renogram shape to an obstructive or non-functioning pattern was observed. The sensitivity and specificity of CRR and change in renogram were 50% and 80%, 63% and 100%, respectively. In BRAS, positive response was observed in the unilateral kidney alone which maintained relatively a good renal function. CP-RG could not differentiate RVH with URAS from that with BRAS. Four patients were followed after the surgical or angioplastic treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗