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Biomedical subjects

N Oriuchi

Publications and source records attributed to N Oriuchi.

At least 73 records · Page 4Linked to original sources
PubMed1996

Evaluation of gamma camera-based measurement of individual kidney function using iodine-123 orthoiodohippurate.

Gamma camera-based clearance techniques which use the renal uptake ratio (RUR) of the radiotracer are available to estimate the effective renal plasma flow (ERPF) and glomerular filtration rate. To evaluate the accuracy of these techniques, we measured RUR by an optimized procedure and compared it with standard ERPF. Iodine-123 orthoiodohippurate (OIH) scintigraphy and simultaneous para-aminohippurate clearance study for measuring standard ERPF were performed in three hospitals in 24 patients with normal or mildly impaired renal function. 123I-OIH was injected intravenously and 10-s consecutive imaging of the kidneys was started when the abdominal aorta was seen. The attenuation coefficient for 123I was measured in each hospital using the same water-equivalent absorption materials and used for the attenuation correction. After subtracting background radioactivity, RURs were defined as the count ratios of fractional renal uptakes based on the integral from 1 to 2, 2 to 3, 1.5 to 2.5 and 1 to 3 min after the injection of 123I-OIH in relation to injected doses using the following three procedures in respect of attenuation correction: (1) RUR without attenuation correction, (2) RUR with fractional renal uptake corrected by the measured attenuation coefficient, (3) RUR with the total injected dose corrected by the absorption material. To decide upon the appropriate correction method and time interval, RURs were compared with standard ERPF. Among the three correction methods, procedure 2 showed the highest correlation between RUR and standard ERPF, but the correlation coefficient was low (r=0.75). No significant difference was observed among the RURs of each time interval. Individual kidney function measured from early renal uptake may be inaccurate even when appropriate correction is made for attenuation, background activity or time lag between injection and data acquisition. Gamma camera-based measurement of renal function using 123I-OIH is limited with regard to accuracy and reproducibility, though it is convenient and non-invasive.

Adult↗
PubMed1996

Indirect labeling of macroaggregated albumin with indium-111 via diethylenetriaminepentaacetic acid.

It is ideal to perform a simultaneous pulmonary perfusion and ventilation scan in cases of suspected pulmonary thromboembolism. Indium-111 (111In)-diethylenetriaminepentaacetic acid (DTPA)-macroaggregated albumin (MAA) was designed for this purpose. MAA was conjugated with DTPA at a molar ratio of 1:100 and incubated with 111In-chloride for 30 min at room temperature. DTPA-MAA could be labelled with 111In above a 96% labelling efficiency without MAA particle aggregates making their particles larger than desirable. The obtained 111In-DTPA-MAA was intravenously injected into normal mice and their biodistribution was studied at 15 and 180 min after injection. A gamma camera image was obtained 15 min after injection. 111In-DTPA-MAA was stable in vitro and in vivo, and gave high uptake of murine lung in the biodistribution study and clearly visualized murine lung in the scintigraph. Using 111In-DTPA-MAA as a pulmonary perfusion agent, a simultaneous pulmonary perfusion and ventilation scan with technetium-99m-ventilation agents is able to be performed using the dual-isotope technique. 111In-DTPA-MAA may be a potential pulmonary perfusion agent.

Albumins↗
PubMed1996

Different biodistribution of 99mTc-labelled chimeric mouse-human monoclonal antibody between athymic mice model and human.

Biodistribution of chimeric mouse/human monoclonal antibody against non-specific cross-reacting antigen (chNCA Ab) was studied in athymic mice and patients with metastatic bone disease. 99mTc-chNCA Ab showed a high labelling efficiency, stability and also a high binding ratio to human granulocytes. Since NCA showed cross-reactivity with carcinoembryonic antigen (CEA), animal experiments showed that 99mTc-chNCA Ab was accumulated in the xenografted tumour which expressed CEA, suggesting the preserved immunoreactivity of labelled materials. In the clinical study, injected 99mTc-chNCA Ab formed a high molecular weight complex immediately after intravenous administration and was trapped mainly in liver. The first-phase plasma half-life was 6.4 +/- 1.1 min. None of the patients showed adverse reaction or human antimurine or anti-chimeric antibody in their serum. 99mTc-chNCA Ab demonstrated remarkably different biodistribution between patients and the animal model and showed different pharmacokinetics from other murine and chimeric Abs reported previously. For safety HPLC analysis should be performed before clinical radioimmunodetection or radioimmunotherapy by incubating radiolabelled MAb with human serum under strict conditions.

Aged↗
PubMed1996

A "changing stripe sign" in serial pulmonary perfusion imaging.

A stripe sign in pulmonary perfusion imaging is reported to be predictive of the absence of pulmonary embolism in the specific area of the stripe sign, and generally does not change on serial pulmonary perfusion imaging. The authors present the case of a patient with a stripe sign that disappeared on serial perfusion imaging without a ventilation abnormality. A "changing stripe sign" may raise suspicion for the possible existence of acute pulmonary embolism.

Aged↗
PubMed1996

A human/mouse chimeric monoclonal antibody against intercellular adhesion molecule-1 for tumor radioimmunoimaging.

A mouse-human chimeric antibody for intercellular adhesion molecule-1 (ICAM-1) was established by using heavy chain loss mouse mutant hybridoma and human immunoglobulin expression vector. The HA58 hybridoma secreted anti-ICAM-1 monoclonal antibody (MoAb) (IgG1, kappa). The gene of the mouse variable region of heavy chain was amplified and cloned by the polymerase chain reaction technique directly from the HA58 hybridoma RNA. The variable region of heavy chain was joined with an expression vector which contains human gamma 1 constant gene. The expression vector was transfected into heavy chain loss mutant cells HA58-7, which produced only murine immunoglobulin light chains. The resultant chimeric MoAb HA58, chHA58, retained full-binding reactivity to ICAM-1 compared with murine HA58 parental antibody. The chimeric MoAb chHA58 showed little antibody dependent cell-mediated cytotoxic activity against cultured tumor cells. Biodistribution studies with 99mTc-labeled chHA58 in nude mice bearing human gastric carcinoma JRST cells demonstrated that the tumor-blood ratio was 1.55 at 18 h after injection, when the tumors were clearly visible in gamma scintigraphy. These data suggest that chHA58 may be of practical use for radioimmunoimaging of a wide variety of tumors.

Amino Acid Sequence↗
PubMed1996

Grade II astrocytoma visualized by technetium-99m-ECD SPECT.

We present a case of primary brain tumor demonstrating increased uptake of 99mTc-ECD. Astrocytoma (Grade II) showed significantly increased cerebral blood perfusion on dynamic images and homogeneously increased uptake on static images with 99mTc-ECD brain SPECT. There seems to be some difference in perfusion and mechanism of tumor uptake among the cerebral blood flow imaging agents (99mTc-ECD, 99mTc-HMPAO and [123I]-IMP) and 201TI-chloride.

Adult↗
PubMed1996

Independent thallium-201 accumulation and fluorine-18-fluorodeoxyglucose metabolism in glioma.

UNLABELLED: SPECT with 201TI is an effective procedure for evaluating the malignancy of glioma. Our goal was to investigate the diagnostic relevance of both 201TI SPECT and [18F]fluorodeoxyglucose (FDG) PET and the relation between 201TI uptake and glucose metabolism in glioma using comparative SPECT and PET studies. METHODS: Thallium-201 SPECT and FDG dynamic PET studies were performed in 20 patients with untreated glioma (5 with glioblastoma, 5 with anaplastic glioma, 10 with low-grade glioma). Thallium-201 uptake in the tumor was estimated using the 201TI index, defined as the ratio of 201TI uptake in the tumor to that in the contralateral normal brain on SPECT images obtained 15 min after intravenous injection. We measured regional glucose metabolic parameters, including rate constants and regional cerebral metabolic rate of glucose utilization (rCMRgl), in the tumor. We then compared the regional 201TI index and glucose metabolic parameters with the histologic characteristics, malignancy and computed tomographic/ magnetic resonance imaging findings. In addition, we investigated the correlation between the 201TI index and glucose metabolic parameters. RESULTS: Thallium-201 SPECT showed abnormal 201TI uptake in all patients with glioblastoma and anaplastic glioma. Thallium-201 indices of glioblastoma (202.6 +/- 22.1%) and anaplastic glioma (176.6% +/- 26.6%) were significantly higher than that for low-grade glioma (106.7% +/- 13.8%). The rCMRgl value of glioblastoma (17.6 +/- 3.5 mumole/100 g/min) was also significantly higher than that for low-grade glioma (10.8 +/- 4.5 mumole/100 g/min), although rCMRgl showed a large variability in both high- and low-grade glioma. Rate constants of FDG kinetics had no correlation with histological grade of glioma. Some patients with high-grade glioma, however, showed false-negative results with FDG-PET because of high normal brain uptake of FDG. Conversely, most low-grade glioma could not be localized by 201TI SPECT. There was no correlation between the 201TI index and glucose metabolic parameters. CONCLUSION: Thallium-201 indices and rCMRgl values for glioblastoma were higher than those for low-grade glioma. Thallium-201 uptake in the tumor may be independent of increased glucose transport or metabolism. Thallium-201 SPECT and FDG-PET are complementary in the diagnosis of glioma, although 201TI SPECT is more significantly correlated with the malignancy of glioma.

Brain Neoplasms↗
PubMed1995

Increased pulmonary clearance of aerosolized 99Tcm-DTPA in patients with a subset of stage I sarcoidosis.

Measurement of the pulmonary clearance of aerosolized 99Tcm-diethylenetriamine pentaacetate (99Tcm-DTPA) as a marker of pulmonary parenchymal damage was performed in 10 non-smokers with sarcoidosis, none of whom was on medication, and the results compared with 12 normal controls. Posterior images were obtained using a single-headed gamma camera, with the subjects in a supine position, for 30 min after inhalation of aerosolized 99Tcm-DTPA had ceased. The pulmonary clearance of 99Tcm-DTPA was significantly increased in the sarcoidosis patients (57.6 +/- 22.1 min in the right lung, 62.2 +/- 22.7 min in the left lung) compared with the controls (79.3 +/- 10.2 and 78.4 +/- 7.7 min in the right and left lungs, respectively) (P < 0.05). Six of the 10 patients with sarcoidosis showed levels of pulmonary clearance, in both the right and left lungs, below the 95.5% confidence limit (mean +/- 2 S.D.) for the controls. Increased pulmonary clearance of 99Tcm-DTPA was also found in 2 of 4 patients with stage I sarcoidosis. No relationship was found between the pulmonary clearance of 99Tcm-DPTA and inflammatory markers (ACE, lysozyme) in the serum.

Adult↗
PubMed1995

Cardiac accumulation of 125I-labeled monoclonal antibody to atrial natriuretic peptide in a rat model of myocardial infarction.

Atrial natriuretic peptide (ANP) may be an important factor in myocardial infarction and subsequent congestive heart failure. In the failing heart, ANP is expressed in both the atrium and the ventricle. ANP has now been localized with 125I-labeled monoclonal antibodies (MAbs) in vivo in a rat model of myocardial infarction. Myocardial infarction was produced in 3-month-old Wistar rats by ligating the left anterior coronary artery. Two MAbs to rat alpha-ANP accumulated in the infarcted left ventricles of treated rats to a significantly greater extent (p < 0.01) than in the noninfarcted left ventricles of control rats. However, an irrelevant MAb also accumulated to a significantly greater extent in infarcted myocardium than in control myocardium. Thus, the accumulation of the two MAbs to ANP in infarcted tissue seems to be nonspecific and may be due to increased permeability of the injured myocardium.

Animals↗
PubMed1995

Semiquantitative SPECT tumor uptake of technetium-99m-labeled anti-CEA monoclonal antibody in colorectal tumor.

UNLABELLED: Technetium-99m-BW431/26 images were compared to images of resected tumor specimens to evaluate the efficacy and accuracy of SPECT imaging of colorectal carcinoma. METHODS: Immunoscintigraphy with 99mTc-BW431/26 was performed on seven patients with colorectal carcinoma and one patient with a benign colorectal tumor. Accumulation of 99mTc-BW431/26 in the tumor was expressed as the tumor-to-normal tissue count ratio (SPECT T/N ratio) calculated by a region of interest method on the SPECT images obtained 24 hr after administration of 99mTc-BW431/26. All patients underwent research of the tumor immediately after 24-hr imaging, and the radioactivity in tumor specimen and normal tissue was measured to calculate the tissue T/N ratio. RESULTS: SPECT demonstrated definite increased tracer uptake by the tumor in all colorectal cancer patients. The benign lesion showed tracer uptake to a lesser extent. SPECT, however, failed to visualize a 10-mm lesion in a patient with familial adenomatous polyposis despite a tissue T/N ratio of 4.8, while autoradiography showed radioactivity uptake in the polyps. CONCLUSION: Although SPECT has limitations in detecting small lesions because of its limited spatial resolution, T/N ratios could be measured exactly by SPECT if the lesion is of a certain volume. SPECT imaging with 99mTc-BW431/26 can precisely evaluate tracer uptake in tumors and predict the efficacy of radioimmunotherapy in patients with colorectal cancer.

Adenocarcinoma↗
PubMed1995

Effect of inhaled furosemide on lung clearance of technetium-99m-DTPA.

UNLABELLED: The diuretic furosemide has been reported to have a protective effect on allergic asthmatic reactions. This study was performed to investigate the effect of aerosolized furosemide on the lung clearance of 99mTc-diethylene triamine pentaacetic acid (99mTc-DTPA). METHODS: Pulmonary clearance rates of 99mTc-DTPA were measured by a computerized gamma camera with and without the inhalation of aerosol furosemide in 6 nonsmoking normal volunteers (Group 1), 7 smokers without pulmonary disease (Group 2) and 11 patients with asthma (Group 3). RESULTS: None of the six normal volunteers showed significant effects of inhaled furosemide on the 99mTc-DTPA clearance rates. Three of seven smokers presented an accelerated 99mTc-DTPA clearance by inhaled furosemide and the other four showed no significant change of 99mTc-DTPA clearance by furosemide inhalation. However, in 10 of 11 patients with asthma, there was significant suppression of 99mTc-DTPA clearance by furosemide inhalation. CONCLUSION: Asthmatics possess a furosemide-sensitive mechanism. Pulmonary aerosol scintigraphy with 99mTc-DTPA will be useful in predicting the effect of inhaled furosemide therapy.

Administration, Inhalation↗
PubMed1995

Presurgical diagnosis of a primary carcinoid tumor of the thymus with MIBG.

A primary carcinoid tumor of the thymus showing ectopic ACTH syndrome was evaluated scintigraphically with four radiopharmaceuticals and a fluorescence method. Iodine-123-MIBG and 201Tl-Cl scintigraphy clearly demonstrated the tumor. Gallium-67-citrate and 99mTc(V)-DMSA showed no tumor uptake. The fluorescence method confirmed numerous storage granules of norepinephrine. Iodine-123-MIBG scintigraphy could be useful in the presurgical diagnosis of carcinoid tumors of the thymus.

3-Iodobenzylguanidine↗
PubMed1995

[Unilateral effective renal plasma flow measurement using one-compartment analysis of 99mTc-MAG3 and gamma-camera renography].

The aim of this study was to establish a simple and accurate procedure to calculate the unilateral effective renal plasma flow (ERPF) using 99mTc-MAG3 gamma-camera renographyl. Eleven patients with urological disorders were studied with 99mTc-MAG3 to calculate the renal uptake ratio (RUR), which was defined as the ratio of absorption-corrected renal counts within 1-2 min after intravenous injection to injection radioactivity measured with a gamma-camera. We assumed that 99mTc-MAG3 was distributed in the circulation, moved from the circulation to the kidneys, and was excreted solely from the kidneys. We thus adopted an one-compartment model to calculate 99mTc-MAG3 clearance (CLMAG) using RUR. Sequential p-aminohippurate (PAH) clearance study was performed as a gold standard in all the patients to compare CLMAG and PAH clearance. Obtained CLMAG correlated well with PAH clearance, and this one-compartment model seemed appropriate for describing CLMAG. Unilateral ERPF was accurately measured within two minutes after the intravenous injection of 99mTc-MAG3 in conjunction with the renal imaging study. This procedure is simple and reliable, and requires no blood or urine sampling.

Adult↗
PubMed1994

Radioimmunoscintigraphy of colorectal cancer with technetium-99m-labeled murine anti-carcinoembryonic antigen monoclonal antibody in athymic nude mice.

Technetium-99m(Tc-99m) is an ideal radionuclide for clinical use. A murine monoclonal antibody (Mab) designated F33-104 binds to specific parts of carcinoembyronic antigen (CEA). In the present study, intact Mab F33-104 was labeled with Tc-99m, and the immunoreactivity and biodistribution of Tc-99m-labeled F33-104 were studied in athymic nude mice bearing human colorectal cancer xenografts. Mab F33-104, reduced under optimal conditions, was quickly and stably tagged with Tc-99m without loss of immunoreactivity. Higher tumor uptake of Tc-99m-labeled F33-104 was noted in the biodistribution, resulting in a higher localization index and specific-to-non-specific tumor ratio than those of radioiodinated F33-104. These results suggest the potential of Tc-99m-labeled Mab F33-104 for the radioimmunoimaging of colorectal cancer.

Animals↗
PubMed1994

Reversible functional asplenia. Autoimmune hemolytic anemia with thrombocytopenia in chronic lymphocytic leukemia.

An enlarged spleen failed to accumulate Tc-99m-labeled phytate, but it showed normal perfusion and uptake of labeled and heat-denatured red blood cells. A blood cell count demonstrated moderately low hemoglobin and hematocrit levels and a markedly low platelet count, and results of direct Coombs' and antiplatelet-antibody (IgG) tests were positive. Steroid therapy resulted in normal splenic function. This case demonstrates reversible functional asplenia caused by reticuloendothelial dysfunction secondary to pure splenic chronic lymphocytic leukemia.

Anemia, Hemolytic, Autoimmune↗