[An evaluation of characteristics of motion corrector attached to a gamma-camera (author's transl)]

The characteristics of the motion corrector system attached to LFOV gamma-camera (Searle) was evaluated using a T-shaped plane source and point sources. The random movement without rotation of a T-shaped plane source was successfully corrected. However, rotating motion of the plane source was not corrected. When a point source placed on a rotating table, ring images were obtained. When motion corrector was used, the radius of ring images was increased with the increase of rotating speed and it was decreased with the increase of radioactivity of the source. Line images were obtained when point sources were placed on a shaker, which caused linear periodic motion of the sources. The use of the motion corrector reduced the length of line images.

1-year controlled trial of 1 alpha-hydroxycholecalciferol in patients on maintenance hemodialysis

A 1-year controlled trial was performed to confirm the effects of 1 alpha-hydroxycholecalciferol (1 alpha-OH-D3) in chronic hemodialysis patients. Initially, a daily dose of 2 micrograms of 1 alpha-OH-D3 was given orally to 24 patients and its placebo to another 24 patients during the first 3 months. For the following 9 months the dose of 1 alpha-OH-D3 or its placebo was reduced to 1 microgram per day in the individual groups. Serum calcium was significantly increased to the normal level after 1 month of treatment and sustained at this level for 1 year. Serum parathyroid hormone was significantly decreased at 3 months. Serum alkaline phosphatase was decreased to the normal level at the 5th month and thereafter. At 2 months serum phosphorus was significantly increased in the 1 alpha-OH-D3 group. None of the patients on 1 alpha-OH-D3 showed increased subperiosteal resorption on X-rays, whereas 8 out of 20 patients on placebo did (p less than 0.002). No adverse effects were seen apart from 3 patients with the 'red eye' of scleral calcification.

Idiopathic membranous glomerulonephritis associated with diabetes mellitus: light, immunofluorescence and electron microscopic study

The present study described 3 patients with idiopathic membranous glomerulonephritis associated with diabetes mellitus. Clinical characteristics of the 3 patients contrasted with diabetic glomerulosclerosis in the following manner: absence of diabetic retinopathy and neuropathy, and presence of nephrotic syndrome associated with relatively short duration of diabetes mellitus. Renal histology showed the characteristic changes of membranous glomerulonephritis along with those of diabetic glomerulosclerosis. Immunofluorescent studies demonstrated a granular pattern of IgG and C3 deposits along the glomerular capillary wall. Electron microscopic study also demonstrated thickening of glomerular basement membrane and increase of mesangial matrix as well as the presence of electron-dense deposits primarily in the subepithelial and mesangial areas.

Comparison of hemodynamics induced by conventional acetate hemodialysis, bicarbonate hemodialysis and ultrafiltration

Six patients on conventional acetate hemodialysis who had a marked decrease in total peripheral resistance index (TPRI) and hypotension after dialysis were selected for study. Systemic hemodynamic factors such as cardiac output, blood pressure, hematocrit and heart rate were measured, and the values were compared to those found after bicarbonate hemodialysis (Bi-HD) or ultrafiltration without simultaneous dialysis (UF) in the same patients. After Bi-HD and UF, the hemodynamic indices remained stable. Hematocrit level was significantly elevated after Bi-HD (+2.7%, P less than 0.05). Heart rate was insignificantly increased after each procedure. We concluded that Bi-HD can prevent unpleasant side effects induced by the decrease in TPRI with acetate hemodialysis. The stability of TPRI resulting from the increase in hematocrit level during Bi-HD may contribute to the prevention of cardiovascular instability.

Neutralizing antibodies to bovine thyrotropin in immunized patients with thyroid cancer

Bovine thyrotropin (bTSH) was administered to 17 patients who had thyroid carcinoma. Anti-bTSH antibodies in the patients' sera were detected by three methods: 1) cross-reaction of sera in a homologous bTSH RIA, 2) [125I]bTSH binding to the patients' sera using charcoal to separate bound from free fractions, and 3) gel filtraton to detect [125I]bTSH bound to anti-bTSH in patients' sera. Immunoreactive anti-bTSH antibodies were thus demonstrated in 14 patients. These patients showed specific binding of their sera to [125I]bTSH with the charcoal separation of free from bound hormone. A high titer of antiserum (1:10,000) was found in those patients whose sera reacted strongly in the bTSH RIA (greater than 50 mu U/ml). The binding capacity of the serum of 1 patient was estimated as 2,600 mu U/ml serum. Ten of the patients' sera which showed immunoreactivity to bTSH neutralized bTSH activity in the McKenzie mouse bioassay but did not neutralize the activity of human TSH in this bioassay. Repeated administration of bTSH to 14 patients resulted in development of immunoreactive and neutralizing anti-bTSH antibodies. Development of immunological resistance to bTSH appears inevitable in patients who receive repeated injections of this hormone. Because of the loss of effectiveness of bTSH by antibody formation, the repeated diagnostic and therapeutic use of bTSH is not recommended.

Comparison of thyroid stimulators and thyroid hormone concentrations in the sera of pregnant women

To clarify the role of various thyroid stimulators in normal human pregnancy, we measured serum TSH, chorionic TSH (hCT), hCG, bioassayable thyroid-stimulating activity, T4, T3, T3 uptake, free T4 and free T3 indexes, free T4, and free T3 by dialysis in 339 serum samples from pregnant women at various intervals of pregnancy and in 40 normal female controls. Serum T4 and T3 and free T4 and free T3 indexes were significantly elevated throughout pregnancy in comparison with controls. Free T4 concentration was elevated after 10 weeks of pregnancy and free T3 concentration was elevated at 13--20 weeks. Bioassayable thyroid-stimulating activity was elevated from 9--16 weeks when serum hCG concentrations were highest. Serum TSH levels were significantly lower at 9--12 weeks compared with the rest of pregnancy. hCT was detected in only 35% of sera tested; the mean detectable value was 0.60 +/- 0.04 (SE) microU/ml; only 15% of the detectable values exceeded 1 microU/ml. The level of hCG correlated with bioassayable thyroid-stimulating activity (P less than 0.01). The data indicate that hCT is not a significant thyroid stimulator. We propose that hCG, as a weak thyroid stimulator, causes a modest rise in free thyroid hormone levels early in pregnancy which in turn causes a modest reduction in pituitary TSH secretion.

Extraction of human chorionic thyrotropin (hCT) from term placentas: failure to recover thyrotropic activity

We extracted human placentas by three methods to obtain chorionic TSH (hCT). The extracts were assayed by a sensitive homologous RIA for bovine TSH with an antibody which had veen used previously for assay of hCT. Based on the RIA for hCT, the yield of hCT was only 0.68 +/- 0.15 (SE) mU/100 g placenta by the Bates method, 2.01 +/- 0.35 mU/100 g by the Reisfeld method, and 4 mU/100 g by a Concanavalin A-Sepharose technique. Thyrotropic activity was detected by bioassay only in one Reisfeld extract; this biological activity could be attributed to hCG in this fraction. In TSH bioassays of other extracts, the responses were less than the sensitivity of the assay; some extracts were lethal to the bioassay mice. The low yield of hCT, about one-tenth to one-hundredth of that reported previously, casts doubt on the validity of the previous observations.

Effect of thyroid hormone, actinomycin D, cycloheximide and puromycin on TRH-induced secretion of TSH, as studied by pituitary concentration of cyclic AMP and intrathyroidal colloid droplet formation

In an attempt to study the functional relation between pituitary cyclic AMP and TSH secretion in response to thyrotropin releasing hormone (TRH) or thyroid hormone administration, pituitary concentration of cyclic AMP was measured by protein binding assay after in vivo and in vitro administration of test materials (TRH, thyroxine, triiodothyronine, actinomycin D, puromycin and cycloheximide singly or in combination). Small dose of TRH apparently augmented TSH secretion as evidenced by a marked increase of intrathyroidal colloid droplet, but failed to elevate the pituitary concentration of cyclic AMP. Triiodothyronine (T3) and thyroxine (T4) blocked an increase of TSH secretion produced by TRH, but they elevated pituitary concentration of cyclic AMP in vivo and in vitro. Actinomycin D (Act D), puromycin and cycloheximide elevated pituitary cyclic AMP concentration without stimulating TSH secretion. From the data accumulated, it appears that the measurement of total anterior pituitary concentration of cyclic AMP is not useful to evaluate the activity of TSH cells in response to thyroid hormone, TRH and TRH plus thyroid hormone.

An increase of pituitary 3', 5' cyclic adenosine monophosphate produced by estradiol benzoate in vitro: possible implication of this increase in the secretion of luteinizing hormone

In an attempt to study the site and mechanism of action of estrogen in producing positive feedback control, porcine anterior pituitary slices were incubated in vitro in the presence of estradiol benzoate (EB). EB elevated pituitary cyclic AMP concentration within 5 min and augmented pituitary release of luteinizing hormone (LH). The magnitude of increase of cyclic AMP and LH release was related to the doses of EB used. Also, luteinizing hormone releasing hormone (LH-RH) elevated pituitary cyclic AMP concentration and stimulated pituitary release of LH. The magnitude of increase of cyclic AMP and LH release was inversely related to the doses of LH-RH used. EB and LH-RH were additive in increasing cyclic AMP. Progesterone and clomiphene citrate interfered with an increase of pituitary cyclic AMP produced by EB, but did not significantly affect the basal level of pituitary cyclic AMP. Testosterone propionate, human chorionic gonadotropin and hexestrol were without effect on either basal or stimulated level of pituitary cyclic AMP. Since cyclic AMP and dibutyryl cyclic AMP (DBC) stimulated LH release, it is suggested that EB directly stimulates the release of LH by augmenting cyclic AMP synthesis in the anterior pituitary.

Abnormal thyroid function in spontaneously hypertensive rats

Thyroid weight, thyroidal radioiodide uptake, and cyclic AMP-dependent protein kinase activity of a thyroid supernatant fraction were increased significantly in spontaneously hypertensive rats (SHR), apparently because of increased secretion of pituitary TSH. However, the thyroids of SHR did not make supernormal amounts of thyroxine (T4), and thyroidal radioiodine release was apparently impaired. In the SHR, proteolytic enzyme activity was less than normal and the thyroglobulin was more resistant to normal proteolytic enzyme than was control thyroglobulin. Presumably because of these abnormalities, plasma T4 was significantly lower than normal, but triiodothyronine (T4) was normal, as a result of compensatory processes occurring in T3 synthesis and hydrolysis of thyroglobulin. T4 and T3 were less effective in depressing pituitary TSH synthesis and secretion in SHR than in controls, possibly because of an abnormal setting of the "hormostat." Although the hypothalamic content of TRH was normal in SHR, the exact site of the abnormality in the "hormostat" is not delineated in the present study.

Pituitary unresponsiveness to thyrotropin-releasing hormone in thyrotoxic patients during chronic anti-thyroid drug therapy and in rats previously treated with excess thyroid hormone

In an attempt to study pituitary-thyroid feedback control in thyrotoxic patients, TRH tests were performed in 10 thyrotoxic patients who were treated for varying intervals with propylthiouracil. Plasma TSH was undetectable before and after administration of 500 mug TRH in 7 patients (euthyroid or hypothyroid) after therapy for 1 to 4 months. Also, plasma TSH was undetectable before and after TRH in 3 patients who had been euthyroid for at least 6 months. To explore this abnormality, rats were made thyrotoxic by administering large doses of thyroxine or desiccated thyroid for 3 to 28 days. Discontinuation of thyroid hormone administration was followed by a significant but temporary fall of plasma thyroxine and triiodothyronine concentration below control levels. Duration of the low plasma thyroxine and triiodothyronine concentration was longer with the prolonged administration of thyroid hormone. Despite low plasma thyroxine and triiodothyronine concentrations, plasma TSH was below normal before and after administration of TRH. This unresponsiveness of the pituitary to TRH may be comparable to that found in thyrotoxic patients receiving antithyroid drugs for a certain period. Since this pituitary unresponsiveness to TRH in rats is due to a depletion of pituitary TSH content, it is suggested that depletion of pituitary TSH in thyrotoxic patients during antithyroid therapy is the cause of pituitary unresponsiveness to TRH.