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Biomedical subjects

K Torizuka

Publications and source records attributed to K Torizuka.

At least 91 records · Page 5Linked to original sources
PubMed1987

Ovarian cystic teratomas: MR imaging.

Magnetic resonance (MR) imaging characteristics of ovarian cystic teratomas were evaluated in 18 patients with 23 surgically proved tumors. The fat within the tumor demonstrated characteristic intensity similar to that of subcutaneous fat and a pathognomic pattern of chemical shift artifact that helped differentiate ovarian cystic teratomas from endometrial cysts. In addition to fat, MR images of ovarian cystic teratomas had several other characteristics that allowed confident diagnosis, including gravity-dependent layering or floating debris, palm tree-like protrusions or rounded nodules (dermoid plugs), and, occasionally fat-fluid levels and globular calcification. MR images were diagnostic in 20 tumors and were able to depict a tumor measuring 2 cm in diameter. MR imaging appears to be valuable in problematic cases in which other modalities are not diagnostic.

Adolescent↗
PubMed1987

Vaginal agenesis: classification by MR imaging.

Vaginal agenesis was studied by magnetic resonance (MR) imaging lin a 15-year-old girl, a 19-year-old woman, and a 21-year-old woman. In each case MR studies demonstrated the presence or absence of a normal cervix and functioning endometrium. This information was useful in planning surgical management. MR imaging assisted in the classification of the abnormality by noninvasively demonstrating the details of pelvic anatomy-and the uterine morphologic characteristics.

Adolescent↗
PubMed1987

End plate of the discovertebral joint: degenerative change in the elderly adult.

Degenerative change at the end plate of the discovertebral joint was studied in the elderly adult by correlating the histologic and radiographic findings. Undecalcified ground sections were made from 21 autopsied lumbar spines that demonstrated no evidence of disease except age-related osteoporosis. Histologic examination showed that the cartilaginous end plates were degenerated to various extents and were replaced by subchondral bone proliferation (endochondral bone formation) in the direction of the joint space. In advanced cases, this histologic finding was reflected in radiographs as a subchondral sclerotic zone protruding toward the disk space. The degree of end-plate change was positively correlated with disk-space narrowing and the vacuum phenomenon (degeneration of the nucleus pulposus) but not with osteoporosis and vertebral compression. Anatomically and functionally, this may be the most common form of degeneration at the discovertebral joint end plate. Further study will be necessary to clarify the process.

Aged↗
PubMed1987

Carbachol regulates cholecystokinin receptor on pancreatic acinar cells.

We have examined the effect of carbamylcholine on the binding of cholecystokinin (CCK) to dispersed acini from rat pancreas. The CCK receptor on pancreatic acini possesses two classes of binding sites. Simultaneous addition of carbamylcholine inhibited binding of CCK to acini due to an apparent loss of high affinity CCK binding sites. Atropine prevented the inhibitory effect of carbamylcholine, whereas calcium ionophore A23187 did not alter binding of CCK. 12-O-tetradecanoylphorbol-13-acetate (TPA) inhibited binding of CCK in the same manner as carbamylcholine. Inhibition by carbamylcholine was reversible and the recovery was time dependent. By contrast, inhibition of binding of CCK by TPA did not reverse after a 60-min incubation without the agent. These findings, at least in part, account for the inhibition of the CCK-induced stimulation of amylase secretion by carbamylcholine. The action of TPA on binding of CCK suggests the possible involvement of the activation of protein kinase C in the inhibition of binding.

Animals↗
PubMed1987

Inhibition of thyrotropin-induced growth of rat thyroid cells, FRTL-5, by immunoglobulin G from patients with primary myxedema.

We studied thyroid growth-blocking activity in immunoglobulin G (IgG) fractions of serum from 24 patients with primary myxedema, 24 patients with goitrous Hashimoto's thyroiditis, and 18 normal subjects by measuring the ability of their IgG to inhibit TSH-induced [3H]thymidine incorporation into DNA in a rat thyroid cell line, FRTL-5. Both groups of patients were receiving T4 when studied. [3H]Thymidine incorporation induced by 0.1 mU/ml bovine TSH was significantly inhibited by the addition of 2 mg/ml IgG from patients with primary myxedema (P less than 0.01), while it was not affected by IgG from the normal subjects or 23 of the 24 patients with goitrous Hashimoto's thyroiditis. IgG from patients with primary myxedema also inhibited the [3H]thymidine incorporation induced by Graves' IgG, but not that induced by forskolin, cholera toxin, (Bu)2cAMP or phorbol-12-myristate-13-acetate. The inhibition of TSH-induced [3H]thymidine incorporation by IgGs from patients with primary myxedema was significantly correlated with their inhibitory activities against both TSH-induced cAMP generation and TSH binding (P less than 0.001). These data indicate that these growth-blocking antibodies are directed against the TSH receptor and might be one of the causes of the thyroid atrophy in patients with primary myxedema.

Adolescent↗
PubMed1987

Circulating 1,25-dihydroxyvitamin D concentrations in patients with renal cell carcinoma-associated hypercalcemia are rarely suppressed.

We measured serum 1,25-dihydroxyvitamin D concentrations in 18 patients with renal cell carcinoma-associated hypercalcemia. Only 2 patients (11%) had low serum 1,25-dihydroxyvitamin D (less than 15 pg/ml) levels, and the mean 1,25-dihydroxyvitamin D level in the 18 patients was 44 +/- 30 (+/- SD) pg/ml, not different from the value of 42 +/- 22 pg/ml in 75 age-matched normocalcemic patients with various malignancies. Eighty-seven percent (26 of 30) of the hypercalcemic patients with extensive skeletal metastases due to other malignancies or with hematological malignancies had suppressed serum 1,25-dihydroxyvitamin D levels (less than 15 pg/ml). In hypercalcemic patients with other malignancies and no skeletal metastases, only 54% (21 of 39) had low serum 1,25-dihydroxyvitamin D levels. The mean serum 1,25-dihydroxyvitamin D level in the latter group was 21 +/- 26 pg/ml, significantly lower than that in normocalcemic patients. In renal cell carcinoma-associated hypercalcemia, suppression of circulating 1,25-dihydroxyvitamin D concentrations is uncommon.

Adult↗
PubMed1987

Optimization and clinical assessment of a radioreceptor assay for thyrotropin-binding inhibitor immunoglobulins.

We tried to improve the sensitivity of a radioreceptor assay for thyrotropin-binding inhibitor immunoglobulins (TBII) by modifying assay conditions. About a twofold increase in sensitivity without a loss of reproducibility was obtained by prolonging the incubation of the receptors with test serum from 15 to 120 min before the addition of 125I-labeled thyrotropin. In 20 untreated, 49 treated patients with Graves' disease and 19 patients with euthyroid Graves' disease, TBII activities obtained using 120 min preincubation were significantly higher than those obtained using 15 min preincubation (p less than 0.005). No significant increase in TBII activities was observed in the presence of sera from patients with primary hypothyroidism (n = 17), simple goiter (n = 7), adenomatous goiter (n = 11), thyroid adenoma (n = 11) or cancer (n = 12). TBII were detectable in 15 (47%) of 32 triiodothyronine-nonsuppressible Graves' patients who were receiving maintenance antithyroid drug therapy using 120 min preincubation, while they were positive in only 6 patients (19%) using 15 min preincubation. The assay using a longer preincubation period was found to be sensitive, specific and useful for diagnosis and follow-up of Graves' disease.

Adenoma↗
PubMed1987

HLA-DR antigen expression on intrathyroidal lymphocytes and thyrocytes in Hashimoto's thyroiditis and Graves' disease: an immunohistological study.

In frozen sections of thyroid glands with Hashimoto's thyroiditis (HT) and Graves' disease (GD), infiltrating lymphocytes were tested for their expression of HLA-DR antigens as a marker of in situ activation. In a combination of indirect immunoperoxidase and direct immunofluorescence staining, most of the immunoglobulin D positive mature B cells were found to be DR positive (DR+) in both diseases. In HT, sizable portions of both helper/inducer T (Leu3+) and suppressor/cytotoxic T (Leu2+) cells were DR+ in interfollicular regions as well as in lymphocyte clusters and lymphoid follicles. In GD, the proportion of DR+ cells in the interfollicular Leu2+ population was significantly lower than that of HT. DR+ thyrocytes were seen in all 14 cases of HT and in 14 out of 16 cases of GD, especially in the vicinity of lymphocyte aggregates. The extent of their DR expression was not correlated with the percentage of DR+ cells in either T subset. These results indicate that a significant portion of infiltrating T cells are activated in autoimmune thyroid diseases, and there may be bidirectional interaction between DR+ thyrocytes and DR+ T cells. The difference in frequency of Leu2+ DR+ cells may account for the difference between the immunopathological features of HT and GD.

Adolescent↗
PubMed1987

Cholecystokinin-stimulated pepsinogen secretion and cholecystokinin receptors on gastric chief cells in guinea pigs.

We investigated cholecystokinin (CCK) receptors on isolated gastric chief cells from guinea pig. CCK stimulated pepsinogen secretion from chief cells at the same efficacy as that induced by carbamylcholine. Binding of 125I-labeled CCK-33 (125I-CCK) to chief cells was temperature-dependent, and was saturable and reversible at 37 degrees C. Hofstee plots of the ability of CCK-8 to inhibit binding of 125I-CCK showed a linear regression line, suggesting that CCK receptors possessed one binding site. The dissociation constant of the binding site was calculated to be 3.8 x 10(-10) M. The dose-response curve of CCK for pepsinogen secretion was superimposed on that for the binding to its receptors. These results indicated that gastric chief cells from the guinea pig possess CCK receptors that relate closely to the action of CCK involved in pepsinogen secretion.

Animals↗
PubMed1987

Co-purification of bone resorbing activity and adenylate cyclase stimulating activity from human tumours associated with the humoral hypercalcaemia of malignancy.

We have partially purified a tumour factor capable of stimulating both bone resorption in vitro and cAMP accumulation in osteoblastic ROS 17/2 cells from three human tumours associated with humoral hypercalcaemia of malignancy. Purification of tumour factor by sequential acid urea extraction, gel filtration and cation-exchange chromatography, reverse-phase high performance liquid chromatography followed by analytical isoelectric focussing provided a basic protein (pI greater than 9.3) with a molecular weight of approximately 13,000 as a major component of the final preparation which retained both the two bioactivities. Bone resorbing activity and cAMP-increasing activity in purified factor correlated with each other. cAMP-increasing activity of the factor was heat- and acid-stable, but sensitive to alkaline ambient pH. Treatment with trypsin destroyed cAMP-increasing activity of the factor. Synthetic parathyroid hormone (PTH) antagonist, human PTH-(3-34) completely inhibited the cAMP-increasing activity of the factor. The results suggest that this protein factor, having its effects on both osteoclastic and osteoblastic functions, may be involved in development of enhanced bone resorption in some patients with humoral hypercalcaemia of malignancy.

Adenylyl Cyclases↗
PubMed1987

A sensitive and practical assay for thyroid-stimulating antibodies using FRTL-5 thyroid cells.

A sensitive, precise and practical assay for thyroid stimulating antibodies was developed in which poorly differentiated rat thyroid cells (FRTL-5) were exposed to crude immunoglobulin fractions precipitated from serum with 15% polyethylene glycol under hypotonic conditions. After the incubation at 37 degrees C for 2 h, cAMP released into Hank's medium without NaCl was determined by radioimmunoassay. The removal of NaCl from the isotonic Hank's medium greatly enhanced cAMP production in response to both TSH and thyroid stimulating antibodies. The assay was sensitive enough to elicit an approximately 30-fold increase in cAMP at 10 mU/l bovine TSH. Thyroid stimulating activities measured using FRTL-5 cells significantly correlated with those measured using cultured porcine (r = 0.918, N = 72) or human (r = 0.830, N = 23) thyroid cells. Thyroid stimulating activities were detected in all of the 50 patients with hyperthyroid Graves' disease, the 14 patients with recurrent hyperthyroid Graves' disease, and the 25 patients with ophthalmic Graves' disease. Thyroid stimulating activity was also detected in some patients (9/24, 37.5%) with Hashimoto's thyroiditis whose serum TSH concentrations were higher than 30 mU/l. However, it was completely abolished by pre-treatment of the sera with anti-TSH antibodies. Although thyroid stimulating activities were detected in one of the patients with simple goitre (N = 10) and in one with thyroid cancer (N = 10), none of the patients with silent thyroiditis (N = 7), adenomatous goitre (N = 11), and thyroid adenoma (N = 9) were positive for thyroid stimulating antibodies.

Animals↗
PubMed1987

Direct radiographic magnification with computed radiography.

Computed radiography was combined with a 0.1-mm microfocus radiographic tube to obtain radiographic magnification of a x3 to x5. Gray-scale image processing compensated for the loss of radiographic contrast associated with the high-kilovoltage, short-exposure technique. The high-pass spatial frequency filtering capability of the computed radiography resulted in enhanced edges and increased displayed latitude. The improved image quality obtained by magnification computed radiography allowed delineation of subtle abnormalities and small anatomic structures not apparent on conventional screen-film contact or magnification radiographs.

Humans↗
PubMed1987

[Positron emission computed tomography].

Positron emission computed tomography (PET) provides high quality tomographic images of the heart with accurate attenuation correction. The use of various compounds labeled with ultra-short lived positron-emitting radionuclides, such as 11C, 13N, 15O and 18F, allows physiological and biochemical measurements in vivo. Recently, a few institutions in Japan have introduced this technique into cardiology. Although it requires an enormous cost both for the equipment and for running the system, it is expected to play a major role in nuclear cardiology in the near future.

Carbon Radioisotopes↗