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Biomedical subjects

A Kubo

Publications and source records attributed to A Kubo.

At least 271 records · Page 15Linked to original sources

[Development of a converging collimator for thyroid scintigraphy].

Thyroid scintigraphy is generally performed using a pin-hole or a parallel-hole collimator. The former yields a high resolution image, however, the acquisition time prolongs because the collimation system magnifies a thyroid image. The latter has somewhat low resolution, because the collimation system cannot magnify the thyroid image and it is difficult to close the collimator surface to a patient thyroid. The defects of the above two collimators are distortion or blurs at the thyroid edge of the acquired image. To improve the image quality of the thyroid scintigram, we made computer simulations concerning contrast resolution in comparison of a parallel-hole, pin-hole and converging collimator. The simulations results showed that the contrast resolution by the converging collimator is superior to the other collimators. According to the results, we developed a specially-designed converging collimator (thickness: 100 mm, focal length: 195 mm). We cut an edge of the collimator to decrease the distance between the neck and the collimator surface. Under almost the same conditions for spatial resolution and sensitivity, we compared the effectiveness of the converging collimator with that of the other two collimators; the pin-hole type [medium resolution] and the parallel-hole type [high resolution]. As a result of experiments using a phantom, the converging collimator showed less distortion compared with the other collimators at the deep area of the thyroid phantom.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer Simulation↗

[Estimation of scatter component in SPECT planar image using a Monte Carlo method].

A Monte Carlo simulation was performed to estimate quantitatively the scattered photons in planar images of SPECT. As a phantom we used a water-filled cylinder with a line source and calculated the energy spectra of primary and multiple scattered photons separately at each pixel of the planar images. The energy spectra of primary and scattered photons were studied on following parameters: the size of the phantom; the location of the source; the width of the energy window centered at 72.3 (Tl-201), 141 (Tc-99m), and 159 keV (I-123); and the view angle of the planar images. Obtained results were; (1) the energy spectra of Compton scattered photon varied with the phantom size, the source location, and the photopeak energy, (2) the scattered photons within energy windows of 10-30% centered at the photopeak energy were mainly composed by Compton scatter of the first order, (3) the higher order scattering component of the Compton photons did not represent the location of the line source on the planar image, and (4) the scatter fraction defined by the ratio of the scattered photons to the primary photons increased with increasing the size of the phantom and the width of energy window at the low photopeak energy. From the results, we discussed on the scatter subtraction methods.

Computer Simulation↗

[Evaluation of the lung uptake of 123I-IMP by bronchoalveolar lavage].

A 67-year-old female with radiation pneumonitis in the right upper lobe underwent lung scanning and bronchoalveolar lavage 4 hours after the intravenous injection of 123I-IMP. The lung scanning showed increased accumulation of 123I-IMP, corresponding with the area of radiation pneumonitis. The ratios of radioactivities of the cellular and noncellular components in the bronchoalveolar lavage fluid to that of the serum, were 27.0 and 0.39, respectively. Our results suggest that 123I-IMP or its metabolites are transported through alveolo-capillary barrier and taken up by free cells in the alveolar space after 123I-IMP has been bound to nonspecific receptor sites in the endothelial cell in the capillary lumen.

Aged↗

The behavior of 99mTc-hexamethylpropyleneamineoxime (99mTc-HMPAO) in blood and brain.

99mTc-hexamethylpropyleneamineoxime (99mTc-HMPAO) is a reagent for scanning cerebral blood flow. We investigated how 99mTc-HMPAO changed in the blood and brain. The 99mTc-HMPAO, which was prepared by adding of 99mTcO4- to HMPAO and Sn(II), consisted of primary and secondary complexes, reduced hydrolyzed 99mTc, and 99mTc-pertechnetate. The percentage of the primary complex in 99mTc-HMPAO decreased with time after preparation. The primary complex converted to the secondary one very rapidly in the presence of plasma. When 99mTc-HMPAO was injected into patients, 99mTc activity was immediately partitioned in the plasma fraction, with approximately 60% in whole blood. In plasma, 99mTc was found to be associated with proteins such as albumin and globulin. 99mTc trapped in red cells was not washed out with either plasma or saline. Biodistribution studies showed that the less lipophilic compounds of 99mTc-HMPAO could not pass through the blood brain barrier (BBB), and therefore did not accumulate in the brain. The results of gel chromatography and equilibrium dialysis indicated that no specific 99mTc binding protein was present in the brain. Considering the instability of 99mTc-HMPAO in vivo, we proposed that the speed at which the primary complex converted to the less lipophilic compounds was important in allowing 99mTc-HMPAO to pass through the BBB and to be fixed in the brain.

Animals↗

Usefulness of pinhole collimator in differential diagnosis of metastatic disease and degenerative joint disease in the vertebrae; evaluation by receiver operating characteristics (ROC) analysis.

In order to evaluate the diagnostic efficacy of pinhole collimator (PHC) imaging combined with an X-ray for vertebral metastasis, our prospective study has employed receiver operating characteristics (ROC) analysis in 21 patients, 11 with osseous metastasis and 15 with degenerative joint disease in the lumbar vertebrae. PHC imaging provided better anatomic information on the extent of 99mTc-MDP accumulation. PHC vertebral scintigraphy had a considerable impact on the decision-making process, although with variations and not very satisfactory results among the physicians with little experience. Our study suggests that PHC imaging and X-ray film are useful in differentiating between osseous metastasis and degenerative joint disease in the vertebra.

Aged↗

N-isopropyl-p-[I-123]iodoamphetamine lung imaging in a patient with chronic pulmonary thromboembolism.

A patient with a brain infarct was found to have chronic pulmonary embolism associated with perfusion defects on blood flow imaging with N-isopropyl-p-[I-123]iodoamphetamine (I-123 IMP). However, gradually increasing uptake of I-123 IMP was seen in later images, in areas distal to the embolus. The increased uptake to the embolized lung seemed to be through the systemic collateral circulation.

Aged↗

Detection of granulocyte colony-stimulating factor produced by a newly established human hepatoma cell line using a simple bioassay system.

A colony-stimulating factor(CSF)-producing tumor cell line (KX-87) was established from a patient with hepatocellular carcinoma and marked granulocytosis. This cell line formed tumors on nude mice in high frequency and the mice revealed marked granulocytosis. In clonogenic assays of human bone marrow cells, KX-87 conditioned medium (CM) supported the formation of colonies mainly consisting of neutrophilic granulocytes but had no burst-promoting activity. The molecular weight of the colony-stimulating activity (CSA) in KX-87CM was estimated about 25,000 daltons by gel filtration and a new bioassay system. In principle, a subline of murine hemopoietic cell line NFS-60 was cloned which was dependent on KX-87CM. Then the growth of this subline was examined by a rapid and sensitive colorimetric tetrazolium assay. From these results, it was concluded that the CSA which KX-87 cell line produced was G-CSF.

Animals↗

Comparative studies of the inhibitory properties of antibiotics on human immunodeficiency virus and avian myeloblastosis virus reverse transcriptases and cellular DNA polymerases.

The inhibition of human immunodeficiency virus (HIV) reverse transcriptase by certain antibiotics and related compounds was studied in comparison with that of avian myeloblastosis virus (AMV) reverse transcriptase and cellular DNA polymerases alpha and beta. In general, compounds that inhibited HIV reverse transcriptase also inhibited AMV reverse transcriptase. For example, 10 micrograms/ml of the isoquinoline quinones used in this study inhibited approximately 80% of the activity of reverse transcriptases of HIV and AMV, but did not inhibit the activity of DNA polymerases alpha and beta even at 50 micrograms/ml. AMV enzyme was more sensitive than HIV enzyme to colistin, enduracidins A and B, janiemycin, glysperin A, and thielavins A and B. The streptonigrin alkyl esters, however, inhibited HIV reverse transcriptase only. Sakyomicin A, luzopeptins, ellagic acid and suramine inhibited the activities of reverse transcriptases and cellular DNA polymerases.

Anti-Bacterial Agents↗

[Chronic neutrophilic leukemia associated with monoclonal gammopathy (IgA, kappa type)].

A 62-year-old woman with chronic neutrophilic leukemia (CNL) is described. She presented in February 1988 for evaluation of leukocytosis of 3 years' duration with no complaint. Physical examination was normal. The leukocyte count was 20,100/microliters with 70% segmented neutrophils and 12% band forms. A myelogram showed marked myeloid hyperplasia and plasmacytosis (5.9%). Neutrophil alkaline phosphatase score, serum lysozyme and vitamin B12 levels were elevated. Cytogenetic analysis of the marrow aspirate showed normal karyotype, with no Philadelphia chromosome. Total serum protein (TP) was 7.5 g/dl with increased beta-globulin (23.5%), identified as monoclonal IgA kappa (3.3 g/dl) on immunoelectrophoresis. No activity of G-CSF was detected in the serum. A retrospective study revealed that the beta-globulin level was normal (6.3%, TP 6.9 g/dl) in 1980 and that it was slightly increased (11.6%, TP 7.0 g/dl) without leukocytosis (5,900/microliter) in 1981. In 1985, when leukocytosis obviously existed (9,900/microliter), the percentage of beta-globulin was increased to 17.5% (TP 7.2 g/dl). The possibility that monoclonal gammopathy preceded the leukocytosis must be admitted. On the basis of our observation, it is assumed that CNL and monoclonal gammopathy may be blood dyscrasias derived from a common precursor cell or that the immunological abnormality associated with monoclonal gammopathy may be implicated in the development of CNL.

Female↗

[Experimental radioimmunoimaging of human lung small cell carcinoma xenograft H-69 by NCC-ST-433 monoclonal antibody].

NCC-ST-433 monoclonal antibody raised against human gastric carcinoma xenograft (St-4) was labeled with 125I using enzymatic and Iodogen methods. While labeling efficiency of the antibody was more excellent by enzymatic method, specific radioactivity of the antibody labeled by Iodogen method was higher than that by enzymatic method. The labeled antibody was stable in vitro and in vivo, and the labeled NCC-ST-433 was specifically accumulated in NCC-ST-433 antigen positive human tumor cell lines in vitro. The specificity of 125I-NCC-ST-433 in vivo was found to be more excellent when this antibody was labeled by Iodogen method and actually excellent images of H-69, a human small cell lung carcinoma, were obtained 5 days after injection of 7 micrograms of 125I-NCC-ST-433 per mouse. This method seemed to be promising for imaging human lung small cell carcinomas.

Animals↗

[Exploration on the reconstruction of lung image and the estimation of lung tissue volume by single photon emission computed tomography (SPECT)].

We studied the use of single photon emission computed tomography (SPECT) for evaluating lung image and measuring lung tissue volume, in a lung phantom and healthy volunteers. Three conditions of image processing were tested using the phantom, and found out a backprojection method with using a Shepp-Logan filter and a pre-reconstruction smoothing of 3 X 3 pixels to be suited. A lung tissue volume was estimated from the summation of voxels in the region where the SPECT value was greater than an arbitrary threshold level. We changed phantom lung density from 0.34 g/cm3 to 0.58 g/cm3, but there was no significant effect in the estimated volume by the density change. Changes in the lung SPECT images and lung tissue volumes in healthy subjects were studied, after changing the lung volume by applying either continuous negative body-surface pressure (CNP) to the thorax or positive end-expiratory pressure (PEEP). Difference of the lung expansion in the two methods was visualized by the SPECT images. The lung tissue volumes obtained by SPECT were correlated with the functional residual capacity by Helium dilution method (r = 0.91, p less than 0.001). We concluded that lung SPECT could be used clinically to display the distribution of a tracer radio-isotope in the lungs and also used to estimate the lung tissue volume.

Adult↗

[Renography and renal imaging with 123I-orthoiodohippurate; comparison with 131I-orthoiodohippurate].

Renography and renal imaging with 123I-orthoiodohippurate (OIH) were performed in 29 patients with various renal diseases, and a comparison made with 131I-OIH. In all patients, renograms and images with 123I-OIH were superior to those with 131I-OIH, because of the increased density and image excellence of 123I-OIH. In addition, dynamic images to evaluate renal blood flow, as well as high quality sequential excretion images, can be obtained with 123I-OIH. From our clinical results, 123I-OIH is expected to replace 131I-OIH in renal function studies.

Humans↗

[Left ventricular function in right ventricular overload: asymmetry of the left ventricular ejection].

This study clarified regional and global functions of the distorted left ventricle due to right ventricular overload by means of gated radionuclide ventriculography (RNV). Cardiac catheterization and RNV were performed in 13 cases of atrial septal defect (ASD), 13 of pure mitral stenosis (MS), 10 of primary pulmonary hypertension (PPH), and 10 of normal subjects (NL). Right ventricular systolic pressure (RVSP) was 32.9 +/- 13.9, 45.0 +/- 12.2, 88.3 +/- 17.1, and 21.2 +/- 4.5 mmHg, respectively. RNV was performed with a 99mTc-red blood cell in a vivo labeling technique. The end-systolic LAO view of the left ventricle was halved into septal and free-wall sides. The end-diastolic halves were determined in the same plane. Ejection fractions of the global left ventricle (LVEF), global right ventricle (RVEF), the septal half of the left ventricle (SEPEF), and the free-wall half of the left ventricle (FWEF) were obtained. LVEF was 56.8 +/- 9.8% in NL, 52.8 +/- 10.5% in ASD, and 49.5 +/- 12.9% in PPH. In MS, LVEF (47.0 +/- 13.0%) was smaller than those in the other groups. RVEF was 37.0 +/- 5.2% in NL, 43.7 +/- 15.5% in ASD, and 32.8 +/- 11.5% in MS. In PPH, RVEF (25.0 +/- 10.6%) was smaller than those in the other groups. SEPEF was smaller in AS D (42.5 +/- 13.2%), MS (40.4 +/- 13.1%), PPH (40.5 +/- 12.5%) than in NL (53.5 +/- 8.5%). Systolic function of the septal half of the left ventricle was disturbed by right ventricular overload. RVEF (r = -0.35, p less than 0.05) and SEPEF (r = -0.51, p less than 0.01) had negative correlations with RVSP. As RVSP rose, systolic function of the septal half of the left ventricle was more severely disturbed. FWEF was the same among the four groups; NL (57.0 +/- 12.6%), ASD (48.6 +/- 15.2%), MS (50.5 +/- 12.0%), and PPH (51.1 +/- 12.3%). Right ventricular overload does not affect systolic function of FWLV. There was a good correlation between SEPEF and LVEF in NL (r = 0.81), though in PPH this correlation was poor (r = 0.64). In patients with PPH the septal side of the left ventricle does not act as a part of the global left ventricle. Systolic function of the septal side of the left ventricle is disturbed due to the distortion of the ventricular septum, but systolic function of the free-wall side is maintained within a normal range, when the left ventricular myocardium is kept normal.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

[Ulcerative colitis complicated by early carcinoma of the rectum and cholecystolithiasis].

Reported is a case of a 73-year-old male with a history of ulcerative colitis that had started at the age of 57. In 1985, on receiving a barium enema, a polypoid lesion was found in his rectum. In 1986, the results of a colonoscopy showed that the polypoid lesion had reached an IIa-aggregated elevation, and biopsies of this lesion were diagnosed as an adenoma or a hyperplastic polyp. A year later, in 1987, another biopsy specimen was taken and was histologically diagnosed as being an adenomatous cancer. Thus, a pull-through operation and a cholecystectomy were performed. The lesion was 4.5 x 3.0 cm in diameter, and the histological findings showed it to be a well-differentiated adenocarcinoma with a submucosal invasion. Accordingly, physicians should be advised that patients with a longstanding ulcerative colitis ought to undergo periodic examination that includes a colonoscopy and a biopsy of any suspicious growth.

Adenocarcinoma↗

[The effect of airway deposition on the assessment of lung injury by 99mTc-DTPA clearance--lung injury in interstitial lung diseases assessed by using the duplicated 99mTc-DTPA aerosol inhalation method].

The 99mTc-DTPA aerosol inhalation method permits detection of pulmonary epithelial damage. We investigated one of several problems, airway deposition of inhaled aerosol, on the assessment of pulmonary epithelial permeability in healthy nonsmokers and patients with interstitial lung diseases. We used the rate constant of pulmonary 99mTc-DTPA clearance curve, k, as a parameter of the epithelial permeability. The alveolar-peripheral airway deposition of aerosol was estimated by the duplicated inhalation method, which we newly developed. The mean k in patients with interstitial lung diseases (2.52 +/- 0.72%/min, n = 8; p less than 0.01) was significantly greater than that in healthy nonsmokers (0.92 +/- 0.20%/min, n = 4). The alveolar-peripheral airway deposition was similar in both healthy nonsmokers and interstitial lung diseases (73.5 +/- 7.8% and 75.5 +/- 9.2%, respectively). The mean k corrected for alveolar-peripheral airway deposition (corrected k; kc) was higher in patients with interstitial lung diseases (4.08 +/- 1.63%/min; p less than 0.01) as compared with healthy nonsmokers (1.36 +/- 0.47%/min). The mean k was significantly greater than the mean kc in both groups (p less than 0.01, p less than 0.01). However, there was a significant correlation between the k and kc obtained among the subjects (r = 0.951; p less than 0.01). We, therefore, conclude that correction for alveolar-peripheral airway deposition was not necessary to distinguish the patients with interstitial lung diseases from the healthy nonsmokers using 99mTc-DTPA aerosol inhalation method although the correction was significant in the individual subjects.

Adult↗