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Biomedical subjects

K Torizuka

Publications and source records attributed to K Torizuka.

At least 289 records · Page 16Linked to original sources
PubMed1982

[The prognosis of Graves' disease after antithyroid drug treatment: clinical significance of the T3 suppression test and abnormal thyroid stimulators].

The prognostic significance of both the triiodothyronine (T3) suppression test and the detectability of thyroid stimulating immunoglobulins in patients with Graves' disease who had been treated with antithyroid drugs was evaluated. Eighty-three patients underwent a T3 suppression test after having been euthyroid for at least 6 months. In 33 patients, the human thyroid stimulator (HTS) was assayed by measuring cyclic AMP increase in cultured thyroid adenoma cells, and TSH-binding inhibitor immunoglobulins (TBII) were measured by using the radioreceptor assay of TSH. Among 43 patients who had discontinued the drug treatment, 37 patients were under observation for 6-42 months. When a fall in 30-minute thyroid 99mTcO4- uptake of 50% or more after T3 administration was defined as positive suppression, the relapse rate was 30% in non-suppressive cases and 26% in suppressive cases. The relapse rate was lower in cases whose pre-suppression uptake was less than 3.0% (3 out of 17 patients) or in cases whose uptake after T3 administration was less than 0.8% (1 out of 9 patients). Of 15 patients with negative suppression, 5 (33.3%) were positive in HTS and 4 (26.7%) were positive in TBII. On the other hand, two (11.1%) each of 18 patients with positive suppression were positive in HTS and TBII respectively. Neither HTS nor TBII had been detected at the cessation of therapy in any of the 12 patients who remained euthyroid during the follow-up period. On the other hand, four (44.4%) out of 9 patients who relapsed had been positive in either HTS of TBII. Thus the Graves' disease specific immunoglobulins were found to be significantly associated with the relapse of the disease (p less than 0.05). The above data indicates that regardless of the suppressibility of 99mTcO4- uptake after T3 administration, the rate of recurrence is high when the uptake after T3 is more than 0.9% and/or when either HTS or TBII are positive.

Adult↗
PubMed1982

[Studies on the measurement of vitamin D derivatives in human plasma. III. Plasma concentrations of vitamin D derivatives in various diseases (author's transl)].

Plasma concentrations of vitamin D3, 25-OH-D3, 24, 25(OH)2D3 and 1, 25(OH)2D3 were measured in patients with various diseases using the multiple assay system previously reported. In patients with hyperparathyroidism, the plasma levels of 1, 25(OH)2D3 tended to increase, while the levels of 24, 25(OH)2D3 tended to decrease in many cases. On the other hand, plasma 1, 25(OH)2D3 levels were low, while 24, 25(OH)2D3 levels were high in patients with hypoparathyroidism. No significant differences in the levels of plasma D3 derivatives among idiopathic-, postoperative- and pseudo- hypoparathyroidism were observed. In a majority of hemodialyzed patients with advanced renal failure who showed no overt bone changes on X-ray films, both the plasma 1, 25(OH)2D3 and 24, 25(OPH)2D3 levels were distributed from normal to very low. In a majority of patients with osteoporosis and hypoparathyroidism, plasma 1, 25(OH)2D3 levels rose quickly after the administration of 1 alpha-OH-D3. In hypophosphatemic vitamin D resistant rickets, however, the response to the relatively large amounts of 1 alpha-OH-D2 was poor, although the concentrations of plasma 24, 25(OH)2D3 were elevated by the 1 alpha-OH-D3 administration in most of these cases. The plasma 1, 25(OH)2D3 and 24, 25(OH)2D3 concentrations in patients with senile osteoporosis were distributed from lower to higher range than those of normal adults. There was a relatively good correlation between plasma levels of 25-OH-D3 and D3 only in cases with plasma D3 levels higher than 5 ng/ml. In addition, a hyperbolic regression curve was obtained between the plasma D3 and 25-OH-D3 ratio. These results may indicate that a possible negative feedback homeostatic mechanism exists between plasma levels of D3 and 25-OH-D3, but only with low plasma levels of D3.

Calcitriol↗
PubMed1982

67 Ga-labeled human fibrinogen: a new promising thrombus imaging agent.

Gallium-67 labeled fibrinogen was prepared as a new deep-vein thrombus imaging agent, using deferoxamine (DF) as a bifunctional chelating agent. Excellent physicochemical and biological properties of 67 Ga-DF-fibrinogen were obtained. The isotopic clottability was 85.3%. High stability in vivo as well as in vitro was observed. Studies carried out in rabbits with induced thrombi in the femoral vein showed thrombus to blood radioactivity ration of 11.7, comparable to the value estimated with conventional 131I-fibrinogen 24 h after injection. Remarkable visualization of these thrombi with a scintillation camera provided good evidence for the selective mechanism of this new radiopharmaceutical.

Animals↗
PubMed1982

Bone scintigraphy in pulmonary alveolar microlithiasis: a comparative study of radioactivity and density distribution.

A histologically proven case of pulmonary alveolar microlithiasis that demonstrated intense lung uptake of Tc-99m-MDP on a bone scan is presented. The spatial distribution within the lungs of the radioactivity and density was assessed either by single photon emission computed tomography (SPECT), or x-ray computed tomography (CT) respectively, and the regional magnitude of the two parameters were compared. The quantitative study of regional radioactivity and density revealed that both the parameters distributed symmetrically, showing gradual increase in magnitude from the upper to the lower lung regions. The radioactivity-density association observed in our patient may indicate on-going formation of microcalculi throughout the lungs, the degree of which is greater at the sites of more severe involvement.

Bone and Bones↗
PubMed1982

Clinical evaluation of emission tomography using seven-pinhole collimator: improved detection of perfusion defect by the addition of the right anterior oblique projection.

The clinical efficacy of thallium emission myocardial tomography using a seven-pinhole collimator in the right anterior oblique (RAO) projection was evaluated. Myocardial tomography in left anterior oblique (LAO) and RAO projections was performed following planar thallium perfusion imaging at rest in 11 patients with myocardial infarction. The RAO tomogram was useful, especially in detecting apical perfusion defects, while the LAO tomogram was useful in detecting inferior and anteroseptal wall defects. For the four patients without an apparent myocardial perfusion defect seen on the planar image, the LAO tomogram showed a perfusion defect in three, and the RAO tomogram also showed the defect in three. One or the other of the two views demonstrated the defect for all 11 patients. The myocardial tomogram in the RAO projection, providing a sufficiently high-quality and high-contrast image, gives useful information complementary to the findings of the commonly used LAO projection in the evaluation of myocardial infarctions.

Adult↗
PubMed1982

Estimation of infarct size by myocardial emission computed tomography with thallium-201 and its relation to creatine kinase-MB release after myocardial infarction in man.

We evaluated emission computed tomography (ECT) for thallium-201 (201TI) myocardial imaging in estimating infarct size (IS). In 18 patients in whom IS was estimated enzymatically at the time of the acute episode, planar 201TI perfusion scintigraphy and ECT with a rotating gamma camera were performed 4 weeks after the first myocardial infarction. From the size of 201TI perfusion defects, the infarct area in planar images and the infarct volume in reconstructed ECT images were measured by computerized planimetry. When scintigraphic IS was compared with the accumulated creatine kinase-MB isoenzyme release (CK-MBr), infarct volume determined from ECT correlated closely with CK-MBr (r = 0.89), whereas infarct area measured from planar images correlated less satisfactorily with the enzymatic IS (for an average infarct area from three views, r = 0.69; for the largest infarct area, r = 0.73). Although conventional scintigraphic evaluation is useful for detecting and localizing infarction, quantification of ischemic injury with this two-dimensional technique has a significant inherent limitation. The ECT approach can provide a more accurate three-dimensional quantitative estimate of infarction, and can corroborate the enzymatic estimate of IS.

Adult↗
PubMed1982

A new in vitro assay for human thyroid stimulator using cultured thyroid cells: effect of sodium chloride on adenosine 3',5'-monophosphate increase.

A new sensitive in vitro assay for human thyroid stimulator (HTS) was developed using human thyroid adenoma cells in monolayer culture. After being cultured for 2 days, the cells were incubated in 0.3 ml Hank's solution without 0.8% NaCl (medium 1) and with thyroid stimulator (bovine TSH or 3 mg patient serum immunoglobulin G) at 37 C for 2 h. The cAMP generated in the cells and the medium during the incubation was measured by RIA. The assay was sensitive enough to elicit a 1.7- to 7.9-fold increase in cAMP at a TSH concentration of 10 microU/ml. HTS was detected in 33 (82.5%) of the 40 patients with untreated graves' disease using this assay system. In Hank's solution (medium 2), however, HTS was detected in only 5 (23.8%) of the 21 patients with untreated GRaves' disease. cAMP increment upon stimulation by either TSH or HTS in medium 1 was larger than that in medium 2, and the difference in the response to HTS using the two media was much greater than that in the response to TSH. Therefore, all HTS-immunoglobulin G studies showed higher activity using medium 1 than using medium 2 when expressed as bovine TSH equivalent. Analysis by the Lineweaver-Burk plot of dose-response curves of the effect of TSH and HTS stimulation on cAMP increment showed an increase in the Km upon the addition of NaCl to the medium. A similar inhibitory effect of NaCl (150 mM) was also observed in the assay system of human thyroid adenylate cyclase stimulator using crude plasma membrane fractions. In summary: 1) an assay for HTS measuring cAMP production in cultured thyroid adenoma cells was developed and the assay using low NaCL medium was found to be the most sensitive, and 2) the inhibitory effect of NaCl on the response to HTS was much greater than that on the response to TSH. These data suggest different behaviors of these two stimulators at their receptor sites.

Adenoma↗