[Development of a new device for measuring the corrosion rate and evaluation of corrosion resistance of dental silver alloys].
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Biomedical subjects
Publications and source records attributed to K Endo.
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Recent availability of monoclonal antibodies (MoAb) and their radiolabeling through the use of the bifunctional chelating agents (BCA) have become an alternative procedure for in vivo radioimmunodetection. Using a newly synthesized BCA, a p-carboxyethylphenylglyoxal-di(N-methylthiosemicarbazone) (CE-DTS), the coupling and technetium-99m (99mTc) labeling of monoclonal IgG against hCG were carried out. In the system presented, factors affecting stability and immunoreactivity were examined. Immunoreactivity of the original IgG (56C) was preserved by conjugating one CE-DTS molecule per molecule of IgG (56C) using the phosphorylazide method, however, 99mTc labeling pH affected the immunoreactivity and limited the 99mTc labeling reaction between pH 4.5 and 6.2. A screening of labeling conditions, such as pH, reaction time, and reducing agent system were then carried out. Technetium-99m-labeled IgG (56C), [99mTc]CE-DTS-IgG (56C), showed good stability upon incubation with mice sera and comparable mice biodistribution to that of indium-111 (111In) DTPA-IgG (56C). Thus, these results indicate the excellent potential of CE-DTS as a BCA for labeling MoAb with 99mTc.
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We describe autoantibodies against iodinated gastrin in a patient with Graves' disease. Values for serum gastrin differed in this case, depending on which of two different radioimmunoassay (RIA) kits was used. RIA with the dextran-coated charcoal method for separation of free tracer gastrin gave a value less than 9.5 pmol/L, whereas the value by a RIA kit by the double-antibody method was 318 pmol/L. The patient's serum contained a binding protein for 125I-labeled gastrin, as detected by Sephadex G-200 column chromatography. The IgG fraction was responsible for the ability of serum to bind 125I-labeled gastrin. Interestingly, of the two possible forms of iodinated gastrins, monoiodinated (MIT) and diiodinated (DIT) tyrosine-125I-labeled gastrin, only the latter bound to patient's IgG. Furthermore, DIT-gastrin, but not gastrin or MIT-gastrin, inhibited the binding of DIT-125I-labeled gastrin. The patient's serum evidently contains autoantibodies against DIT-gastrin that interfere with RIA of gastrin.
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Carbohydrate antigen (CA) 19-9 is a new tumor marker, defined by a monoclonal antibody. Serum CA 19-9 concentrations and computed tomography (CT) findings were studied in 55 patients with histologically proven adenocarcinoma, and in 22 patients with chronic pancreatitis. CA 19-9 was useful in 83% of cases for the differential diagnosis between pancreatic carcinoma and chronic pancreatitis, and serum CA 19-9 levels in pancreatic carcinoma were highly related to the size of tumors. Serum CA 19-9 levels greater than 37 U/ml were seen in patients with a tumor of less than 3 cm, 3 to 5 cm, and greater than 5 cm in diameter 13% (1/8), 90% (19/21), and 92% (24/26) of cases, respectively. Tumor location, however, was unrelated to serum CA 19-9 value. These results indicated that the measurement of serum CA 19-9 concentrations would be useful in most, if not all, cases for the differential diagnosis between pancreatic carcinoma and chronic pancreatitis, and for the evaluation of tumor burden in patients with pancreatic carcinoma.
Fifty-three untreated patients with histologically confirmed Hashimoto's thyroiditis were divided into two groups according to the echogenicity of the thyroid. In 25 cases, the echogenicity of the thyroid was almost the same as or less than that of the adjacent muscles. Such cases were classified as group A. The other 28 cases were classified as group B. Mean T4 levels in group A were significantly lower than those in group B. In addition, the cases in group A had abnormally low T4 and abnormally high TSH more frequently than those in group B. In all cases in group A, there was severe degeneration and disappearance of thyroid follicles, whereas in most of the cases in group B, follicles of normal size were generally seen. Hypoechogenicity of the thyroid is a sign suggesting hypothyroidism and severe follicular degeneration.
The cortico-cortical projection from area 5 to area 4 gamma was studied in anesthetized cats. Intracortical microstimulation of area 5 produced EPSPs in pyramidal tract (PT) cells in area 4 gamma. Such EPSPs were analysed in a total of 54 fast PT cells. The rising phase of these EPSPs was often composed of fast and slow components. Fast-rising EPSPs (fast component) were produced predominantly by stimulation within layer III of area 5 while slow-rising EPSPs (slow component) were evoked predominantly by stimulation within layer V of area 5. The amplitudes of the fast and slow components of EPSPs produced during repetitive stimulation within layers III and V of area 5 decreased and increased, respectively, with an increase in the stimulus frequency without any appreciable changes in their latency and time-to-peak. The slow component was much less influenced by membrane hyperpolarization than the fast component. Retrogradely labeled neurons were found not only in layer III but also in layer V of area 5 following HRP injection centered on superficial layers (I-III) of area 4 gamma. It is suggested that there are two groups of cortico-cortical neurons in layers III and V of area 5, which may make monosynaptic contact with the proximal and distal sites of fast PT cells in area 4 gamma, respectively.
While 131I-meta-iodobenzyl guanidine (131I-MIBG) scanning has made possible the scintigraphic visualization of pheochromocytoma and neuroblastoma, an accumulation of this agent has recently been reported in medullary thyroid cancer. We present the case of a patient with Sipple's syndrome (multiple endocrine neoplasia type IIa), in whom we were able to identify distant metastases and local invasion of medullary thyroid cancer as well as primary thyroid tumour and right adrenal pheochromocytoma, using 131I-MIBG scans. This case highlights the usefulness of 131I-MIBG in the detection of metastatic medullary thyroid cancer and suggests that this agent may also be of therapeutic use in the treatment of tumours.
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Postsynaptic potentials evoked in hindlimb alpha-motoneurons by stimulation of a cutaneous nerve (sural) with finely graded stimulus strengths were analyzed in the primate, monitoring the spinal cord potentials and afferent nerve volleys in the sural nerve. It was observed that activities in A alpha beta, A delta and C fibers of the cutaneous nerve elicited characteristic excitatory and/or inhibitory postsynaptic potentials (EPSPs and/or IPSPs) with different latencies and durations in extensor and flexor motoneurons. Volleys in A delta fibers of the cutaneous nerve produced EPSPs in 57% of flexor and 31% of extensor motoneurons tested, whereas IPSPs were produced by A delta volleys in 41% of flexor and 62% of extensor motoneurons. EPSPs with longer latencies and longer durations were evoked by cutaneous C fiber volleys in 55% of flexor and 34% of extensor motoneurons, whereas IPSPs due to C volleys were recorded in 9% of flexor and 14% of extensor motoneurons. A alpha beta and A delta volleys caused motoneurons to fire in several instances, and some motoneurons discharged repetitively during the depolarizations evoked by activities in C fibers of the nerve. Central latency for transmission in interneuronal chains in the spinal cord was estimated from the onset of the cord potential (N3 wave) to the onset of the postsynaptic potential evoked by A delta volleys. Ranges of central latencies of the EPSPs and IPSPs evoked by A delta volleys were 2.0-7.0 ms and 3.5-8.5 ms, respectively. It is postulated that there may be at least two interneurons interposed in the excitatory reflex pathway from A delta afferent fibers to motoneurons and the A delta inhibitory pathway may involve longer interneuronal chains. In a few motoneurons, however, sural volleys with strengths sufficient to activate A delta fibers produced EPSPs with a central latency of about 1 ms, suggesting activation of a disynaptic segmental pathway with one interposed interneuron. Stimulation of the sural nerve with strengths sufficient to activate cutaneous C fibers produced slow negative cord dorsum potentials with long latencies. It is proposed that primate motoneurons, which show characteristic postsynaptic potentials evoked by cutaneous A delta and C fiber volleys, may provide a suitable model for analyzing the role of high threshold cutaneous afferent fibers not only in the flexor withdrawal reflex but also in motor control functions.
The effectiveness of Tc-99m bleomycin (BLM) and Tc(V)-99m DMSA are compared with that of Ga-67 citrate, which is currently the most widely used agent. In four patients with lipomatous tumors, the clinical significance of tumor imaging with each of these three agents is discussed and compared. Results indicate that both Tc-99m BLM and Tc(V)-99m DMSA are superior in detecting the extension or localization of liposarcomas.
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A simple, sensitive, and practical assay for thyroid-stimulating autoantibodies (TSAb) was developed in which cryopreserved porcine thyroid cells were incubated with crude immunoglobulin fractions sedimented from serum with polyethylene glycol. In the assay, 1.4- to 2.0-fold and 6- to 12-fold increases in cAMP released into Hank's medium without NaCl were found at 1 and 10 microU/ml bovine TSH, respectively. TSAb were detected in 41 (97.6%) of 42 patients with untreated hyperthyroid Graves' disease, 29 (55.8%) of 52 patients with hyperthyroid Graves' disease who were euthyroid while taking antithyroid drugs, 22 (78.6%) of 28 patients with euthyroid Graves' disease, and none of the patients with simple goiter, adenomatous goiter, thyroid adenoma, or thyroid cancer tested. TSAb activities measured using porcine thyroid cells significantly correlated with those measured using human thyroid adenoma cells (r = 0.908; n = 46; P less than 0.001). Thyroid-stimulating activity was also detected in 11 (28.9%) of 38 patients with Hashimoto's thyroiditis. However, the activity was considered to be due to TSH in the patients' sera, because it was completely abolished by pretreatment with anti-TSH antibodies. Serum TSH concentrations lower than 50 microU/ml did not affect the assay result. In Graves' disease after cessation of antithyroid drugs, 85.7% (12 of 14) of TSAb-positive patients relapsed, while 77.8% (14 of 18) of TSAb-negative patients remained in remission. Thus, the assessment of TSAb was useful as an index to predict prognosis.
Binding of immunoglobulin G (IgG) to Triton-solubilized fat cell membranes crosslinked with 125I-TSH was studied by an indirect immunoprecipitation method. Guinea pig fat cell membranes (FCM) containing TSH receptors with an association constant of 1.92 X 10(9) M-1 were first reacted with 125I-TSH, then treated with a crosslinker, dissuccinimidyl suberate. The dissociation of 125I-TSH from the crosslinked 125I-TSH-FCM complexes due to the addition of 100 mU/ml unlabeled TSH was 9.0%, while it was 33% without the treatment. To the Triton-solubilized FCM crosslinked with 125I-TSH, 50 micrograms each of IgG from 20 normal controls, 20 patients with Graves' disease and 20 with Hashimoto's disease was added and precipitation was effected by adding anti-human IgG. In patients with Graves' disease, 125I-TSH-FCM complexes immunoprecipitated ranged from 1.10 to 4.18% with an average of 2.4 +/- 0.99 (S. D.) % which was significantly higher than those in normal controls (1.6 +/- 0.29%). The values in the patients with Hashimoto's disease averaged 1.7 +/- 0.53 (S. D.) which did not differ significantly from those of controls. The value did not correlate with either TSH-binding inhibiting activities or titers of anti-microsomal antibodies. These data suggest the presence of TSH-receptor antibodies which react with antigens other than TSH-binding sites in the patients with Graves' disease.
Seventeen patients with moderately severe ophthalmopathy due to Graves' disease were treated by cobalt or supervoltage radiotherapy. All patients complained of diplopia. The mean proptosis value was 21.4 mm. Three patients (18%) showed good response, 7 (41%) moderate and 7 minimal or no response. Improvement was noted mainly in soft tissue changes and diplopia, while proptosis decreased in only 5 patients. All except one patient who had marked extraocular muscle involvement revealed by computed tomography responded to treatment. These data indicate that radiotherapy may be indicated in patients with progressive ophthalmopathy, especially in those who are associated with extraocular muscle enlargement.
Sequential changes in thyroid-stimulating antibodies (TSAb) and TSH-binding inhibitor immunoglobulins (TBII) during antithyroid drug treatment were studied in 17 patients with Graves' disease. Before treatment, TSAb and TBII were detected in 17 (100%) and 13 (76.5%) patients, respectively, with a significant correlation between the two activities (r = 0.600, n = 17, P less than 0.02). In 9 patients who became euthyroid as early as after 1-4 months of treatment, the TSAb and TBII activities both gradually decreased, and there was a good correlation between the changes of these activities during treatment. Among the 7 patients in whom small changes in TSAb and TBII activities were observed, 4 showed poor control of the thyrotoxicosis during the whole observation period (7 months-2 years). One patient who showed a marked dissociation between the changes in TSAb and TBII activities developed hypothyroidism, when his TBII became remarkably high. These potent TBII inhibited cAMP production induced by bTSH. These findings indicate that 1) changes in TSAb and TBII activities reflect the clinical course of hyperthyroidism in most patients with Graves' disease, and 2) development of a blocking-type of TBII may induce hypothyroidism in some patients after the treatment.