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N Umezaki

Publications and source records attributed to N Umezaki.

At least 19 recordsLinked to original sources
PubMed1998

Determining the breast-feeding interruption schedule after administration of 123I-iodide.

Radioactivity after administration of 123I-sodium iodide was measured in breast milk samples obtained from a patient with postpartum thyroiditis. The breast milk was collected over 93 h during the infant's regular feeding times. The radioactivity in the breast milk was calculated with a 123I capsule of the same lot number as the standard source. 123I was excreted exponentially with an effective half-life of 5.5 h; 2.5% of the total radioactivity administered was excreted in the breast milk over the 93 h, 95% of which was excreted within the first 24 h, and 98.2% within 36 h. The first milk sample collected at 7 h after administration of the radiopharmaceutical contained 48.5% of the total radioactivity excreted. We estimated the potential absorption of radioactivity to an infant's thyroid in uninterrupted breast-feeding to be 30.3 mGy. With a 24-hour interruption, the absorbed radioactivity would be 1.25 mGy; with a 36-hour interruption, it would be 0.24 mGy. According to our calculations, breast feeding should be curtailed for 36 h to reduce the infant's exposure to 123I radioactivity. By using a correction factor based on maximum radioactivity from another 123I capsule of the same lot, we were able to ascertain the appropriate protocol for our patient and establish a measurement method that can be applied in similar clinical situations.

Adult↗
PubMed1995

Indium-111 antimyosin monoclonal antibody Fab imaging in patients with cardiomyopathy.

Six patients with cardiomyopathy were imaged following intravenous injection of an indium-111 labeled monoclonal antibody directed against the heavy chain of cardiac myosin. Two patients had hypertrophic non-obstructive cardiomyopathy (HNCM), two patients had dilated cardiomyopathy (DCM), and two patients had specific heart muscle disease. One of 2 patients with HNCM and one of 2 patients with DCM had a positive antimyosin scan. The 2 patients with specific heart muscle disease manifested persistent blood pool activity of the antibody, thereby precluding interpretation of the images. The present report demonstrates that antimyosin antibody imaging may provide evidence of myocardial injury, or necrosis in some patients with cardiomyopathy.

Adolescent↗
PubMed1995

Thallium-201 in brain tumors: relationship between tumor cell activity in astrocytic tumor and proliferating cell nuclear antigen.

UNLABELLED: This study was performed to assess the relationship between 201Tl chloride uptake and brain tumor proliferation using monoclonal antibody Ki-67 and proliferating cell nuclear antigen (PCNA). METHODS: Thirty-four patients with brain tumors were studied. Serial SPECT images were recorded and thallium uptake (Tl index) and washout rates in the tumors were calculated. Imaging results were compared with those from biopsy and histology. Cell proliferation was determined by PCNA or Ki-67 monoclonal antibody staining. RESULTS: Thallium-201-chloride indices of the astrocytoma were 1.73 +/- 0.17 and 1.48 +/- 0.07 on early and delayed images, respectively. On the other hand, 201TI indices for anaplastic astrocytoma were 2.60 +/- 1.05 and 1.76 +/- 0.93 and 3.26 +/- 1.63 and 2.23 +/- 0.56 for glioblastoma. The correlation between the 201TI (delay) and Ki-67 indices for astrocytic tumor. There were no significant differences between Ki-67/PCNA indices and washout rates. CONCLUSION: There was a positive correlation between PCNA but not the Ki-67 labeling index and the 201Tl index. With the use of a noninvasive technique, 201TI index supports the PCNA index.

Astrocytoma↗
PubMed1991

Validation of single-photon emission computed tomography (SPECT) using thallium-201 in patients with lung cancer.

To evaluate the primary site, pulmonary hilar, and mediastinal lesions in patients with lung cancer, thallium-201 using single-photon emission computed tomography (SPECT) was used as a tumor agent. The study population consisted of 7 patients (5 men and 2 women), aged 57 to 82 years (mean 68). Tl-201 tomography imaged positive at the primary site in all patients with lung cancer. The images demonstrated the tumor and/or mediastinal lymph nodes that were greater than 2.0cm. In particular, each tomograms facilitated the identification of the Tl-201 increased uptake in proportion to primary site. The short waiting period after injection with Tl-201 clearly offers a major advantage over alternative tumor imaging agents, such as Ga-67 or radiolabeled monoclonal antibodies. Furthermore, Tl-201 SPECT may be useful to detect the tumor and/or mediastinal lymph nodes in patients with lung cancer.

Aged↗
PubMed1991

Assessment of cardiac function using radionuclide techniques--theory, technical considerations and clinical application.

The recent expansion of interventional cardiovascular techniques has stimulated the development of non-invasive cardiac studies, to evaluate the outcome of the interventional therapy. Radionuclide ventriculographic technique provides to quantify global left ventricular systolic/diastolic performance, and evaluate the regional left ventricular wall motion during rest or exercise. This concept was extended from the "bedside" to the ambulatory environment with the description of a battery powered device, the radionuclide ventricular function monitor. To assess the performance of cardiac function using radionuclide ventriculography to that using the ambulatory ventricular function monitor, the systolic and diastolic function were measured at rest in a series of healthy volunteers (n = 10) and in patients with cardiovascular disease (n = 23). Seventeen patients had coronary artery disease (CAD) with prior myocardial infarction, three patients had coronary artery disease, and three patients had dilated cardiomyopathy. The 23 patients manifested a wide variation in LV systolic function. The relationship between the multiple gated acquisition (MUGA)-ejection fraction and the ambulatory ventricular function monitor-ejection fraction correlated well (r = 0.90). As a complement to the radionuclide perfusion studies, cardiac blood pool imaging and radionuclide ventricular function monitoring allow for through non-invasive description of cardiac physiology and function in patients with various cardiac disorders.

Adult↗
PubMed1990

Evaluation of the therapeutic effect of percutaneous nephroureterolithotomy by Tc-99m diethylenetiaminepentaacetic acid (DTPA) renal scintigraphy--alteration of the renal fraction of blood flow, split-GFR, and renal mean transit time.

To evaluate the therapeutic effects of percutaneous nephroureterolithotomy, the renal function of eleven patients with renal calculi was studied, pre- and post-intervention. Renal function was determined, by renal scintigraphy with the renal agent, Tc-99m diethylenetriaminepentaacetic acid (DTPA). In each renal scintigram the renogram curve was analyzed and the following were determined by deconvolution analysis; the renal fraction of blood flow (RFBF), DTPA-glomerular filtration ratio (GFR), and the renal mean transit time (MTT). The successful results in percutaneous nephroureterolithotomy (PNL) was proven using the radionuclide technique in most cases. From these results it can be concluded that renal scintigraphy is an effective procedure to evaluate the effect of PNL for treating renal calculi and secondary hydronephrosis.

Adult↗
PubMed1990

Gallium-67 citrate uptake in experimental tumors and inflammatory lesions--an histo-autoradiographic correlation.

In a DAB-hepatoma organic tumor, Ga-67 accumulated markedly in the hepatocellular carcinoma with scant stroma but not in the cholangioma that was rich in connective tissue. No granulation tissue was formed around the tumor. In transplanted tumors (Ehrlich's tumor and Sarcoma 180), Ga-67 accumulated in the granulation tissue within the fibroblasts, leukocytes and capillaries surrounding the tumor, rather than in the tumor. In inflammatory lesions, Ga-67 uptake was similar in granulation tissue with large numbers of phagocytes, such as leukocytes and histiocytes, and capillaries. There was a very good correlation between the degree of Ga-67 uptake and of cellular infiltration and the proliferation of capillaries. Ga-67 uptake, both in inflammatory lesions and in transplanted tumors, was observed in the granulation tissue. This result implies that the mechanisms of Ga-67 uptake in tumor and inflammatory tissues are not the same, because Ga-67 accumulated in the DAB-hepatoma that had no inflammatory granulation tissue. This study indicates that a non-transplanted tumor is required to study Ga-67 accumulation in tumors, as different results may occur in tumors with and without inflammatory granulation tissue.

Animals↗
PubMed1988

Evaluation of renal first pass blood flow with a functional image technique in hypertensive patients.

The renal circulation of patients with essential hypertension and renovascular hypertension was evaluated using 99mTc-DTPA. The first renal peak count (the first Cmax; FCmax), time phase distribution (the first Tmax; FTmax), and blood velocity (the FCmax/FTmax) were calculated by digital imaging. This yields a visual image of the renal circulation. We consider that the increase in the renal first pass blood flow in patients with essential hypertension is best observed pixel by pixel. The FCmax and FCmax/FTmax images before and after treatment by percutaneous transluminal renal angioplasty in patients with renovascular hypertension clearly show its therapeutic effect. The FI technique, therefore, has the advantage that it can be performed at the same time as the conventional routine examinations of renal function. This makes it very useful clinically.

Adult↗
PubMed1985

Evaluation of portal circulation in rats by rectal administration of 201Tl followed by intrasplenic injection of 51Cr-labeled microspheres.

The heart-to-liver (H/L) uptake ratio in rats was determined 8 min after the rectal administration of 201Tl. Apart from normal controls, three groups of rats were examined; these were composed of animals with induced (1) acute hepatic damage, (2) liver cirrhosis, and (3) partial portal-vein ligation. After the rectal administration of 201Tl, 51Cr-labeled microspheres were injected into the spleen. The radioactivity of the removed liver, lungs, and heart was determined in a gamma-well scintillation counter, and the radioactivity of 201Tl and the 51Cr-labeled microspheres was separately calculated using simultaneous equations derived from the results of a preliminary experiment. The H/L ratios (201Tl) in the normal controls and the animals with acute hepatic damage were not significantly different; however, there was a positive correlation (P less than 0.01) between the H/L ratio and the shunt index (51Cr microspheres) in three groups, i.e., normal controls, liver cirrhosis, and partial portal-vein ligation.

Animals↗
PubMed1982

[Distribution of 67Ga-citrate in 3'-methyl-4-dimethylaminoazobenzene-induced hepatoma of rats].

The distribution of 67Ga-citrate in the hepatoma of rat induced by 3'-methyl-4-dimethylaminoazobenzene was studied. 67Ga uptake ratio resected specimen, autoradiography and histological specimen were compared each other. 67Ga uptake ratio of the tumor was increased 1.6 to 7.2 times (average 4.4) to control group. Regardless of the size of the tumor, macroautoradiographically observed distribution of 67Ga-citrate in the hepatoma was higher in the peripheral zone than in the central zone. Histologically the degeneration of tumor cell was low or absent in the peripheral zone of tumor, whereas it was intense in the central zone. 67Ga-citrate was highly accumulated in the zone which the degeneration was low or absent. We, however, could not demonstrate the site where 67Ga-citrate was incorporated.

Animals↗