Wnt5a-YAP signaling axis mediates mechanotransduction in cardiac myocytes and contributes to contractile dysfunction induced by pressure overload

Non-canonical Wnt signaling activated by Wnt5a/Wnt11 is required for the second heart field development in mice. However, the pathophysiological role of non-canonical Wnt signaling in the adult heart has not been fully elucidated. Here we show that cardiomyocyte-specific Wnt5a knockout mice exhibit improved systolic function and reduced expression of mechanosensitive genes including Nppb when subjected to pressure overload. In cultured cardiomyocytes, Wnt5a knockdown reduced Nppb upregulation induced by cyclic cell stretch. Upstream analysis revealed that TEAD1, a transcription factor that acts with Hippo pathway co-activator YAP, was downregulated both in vitro and in vivo by Wnt5a knockdown/knockout. YAP nuclear translocation was induced by cell stretch and attenuated by Wnt5a knockdown. Wnt5a knockdown-induced Nppb downregulation during cell stretch was rescued by Hippo inhibition, and the rescue effect was canceled by knockdown of YAP. These results collectively suggest that Wnt5a-YAP signaling axis mediates mechanotransduction in cardiomyocytes and contributes to heart failure progression.

The CR9 element is a novel mechanical load-responsive enhancer that regulates natriuretic peptide genes expression

Enhancers regulate gene expressions in a tissue- and pathology-specific manner by altering its activities. Plasma levels of atrial and brain natriuretic peptides, encoded by the Nppa and Nppb, respectively, and synthesized predominantly in cardiomyocytes, vary depending on the severity of heart failure. We previously identified the noncoding conserved region 9 (CR9) element as a putative Nppb enhancer at 22-kb upstream from the Nppb gene. However, its regulatory mechanism remains unknown. Here, we therefore investigated the mechanism of CR9 activation in cardiomyocytes using different kinds of drugs that induce either cardiac hypertrophy or cardiac failure accompanied by natriuretic peptides upregulation. Chronic treatment of mice with either catecholamines or doxorubicin increased CR9 activity during the progression of cardiac hypertrophy to failure, which is accompanied by proportional increases in Nppb expression. Conversely, for cultured cardiomyocytes, doxorubicin decreased CR9 activity and Nppb expression, while catecholamines increased both. However, exposing cultured cardiomyocytes to mechanical loads, such as mechanical stretch or hydrostatic pressure, upregulate CR9 activity and Nppb expression even in the presence of doxorubicin. Furthermore, the enhancement of CR9 activity and Nppa and Nppb expressions by either catecholamines or mechanical loads can be blunted by suppressing mechanosensing and mechanotransduction pathways, such as muscle LIM protein (MLP) or myosin tension. Finally, the CR9 element showed a more robust and cell-specific response to mechanical loads than the -520-bp BNP promoter. We concluded that the CR9 element is a novel enhancer that responds to mechanical loads by upregulating natriuretic peptides expression in cardiomyocytes.

Non-Radioactive In Vitro Cardiac Myosin Light Chain Kinase Assays

Cardiac-specific myosin regulatory light chain kinase (cMLCK) regulates cardiac sarcomere structure and contractility by phosphorylating the ventricular isoform of the myosin regulatory light chain (MLC2v). MLC2v phosphorylation levels are significantly reduced in failing hearts, indicating the clinical importance of assessing the activity of cMLCK and the phosphorylation level of MLC2v to elucidate the pathogenesis of heart failure. This paper describes nonradioactive methods to assess both the activity of cMLCK and MLC2v phosphorylation levels. In vitro kinase reactions are performed using recombinant cMLCK with recombinant calmodulin and MLC2v in the presence of ATP and calcium at 25 °C, which are followed by either a bioluminescent ADP detection assay or a phosphate-affinity SDS-PAGE. In the representative study, the bioluminescent ADP detection assay showed a strict linear increase of the signal at cMLCK concentrations between 1.25 nM to 25 nM. Phosphate-affinity SDS-PAGE also showed a linear increase of phosphorylated MLC2v in the same cMLCK concentration range. Next, the time-dependency of the reactions was examined at the concentration of 5 nM cMLCK. A bioluminescent ADP detection assay showed a linear increase in the signal during 90 min of the reaction. Similarly, phosphate-affinity SDS-PAGE showed a time-dependent increase of phosphorylated MLC2v. The biochemical parameters of cMLCK for MLC2v were determined by a Michaelis-Menten plot using the bioluminescent ADP detection assay. The Vmax was 1.65 ± 0.10 mol/min/mol kinase and the average Km was around 0.5 USA µM at 25 °C. Next, the activity of wild type and the dilated cardiomyopathy-associated p.Pro639Valfs*15 mutant cMLCK were measured. The bioluminescent ADP detection assay and phosphate-affinity SDS-PAGE correctly detected defects in cMLCK activity and MLC2v phosphorylation, respectively. In conclusion, a combination of the bioluminescent ADP detection assay and the phosphate-affinity SDS-PAGE is a simple, accurate, safe, low-cost, and flexible method to measure cMLCK activity and the phosphorylation level of MLC2v.

A molecular triage process mediated by RING finger protein 126 and BCL2-associated athanogene 6 regulates degradation of G0/G1 switch gene 2

Oxidative phosphorylation generates most of the ATP in respiring cells. ATP is an essential energy source, especially in cardiomyocytes because of their continuous contraction and relaxation. Previously, we reported that G₀/G₁ switch gene 2 (G0S2) positively regulates mitochondrial ATP production by interacting with F_OF₁-ATP synthase. G0S2 overexpression mitigates ATP decline in cardiomyocytes and strongly increases their hypoxic tolerance during ischemia. Here, we show that G0S2 protein undergoes proteasomal degradation via a cytosolic molecular triage system and that inhibiting this process increases mitochondrial ATP production in hypoxia. First, we performed screening with a library of siRNAs targeting ubiquitin-related genes and identified RING finger protein 126 (RNF126) as an E3 ligase involved in G0S2 degradation. RNF126-deficient cells exhibited prolonged G0S2 protein turnover and reduced G0S2 ubiquitination. BCL2-associated athanogene 6 (BAG6), involved in the molecular triage of nascent membrane proteins, enhanced RNF126-mediated G0S2 ubiquitination both in vitro and in vivo Next, we found that Glu-44 in the hydrophobic region of G0S2 acts as a degron necessary for G0S2 polyubiquitination and proteasomal degradation. Because this degron was required for an interaction of G0S2 with BAG6, an alanine-replaced G0S2 mutant (E44A) escaped degradation. In primary cultured cardiomyocytes, both overexpression of the G0S2 E44A mutant and RNF126 knockdown effectively attenuated ATP decline under hypoxic conditions. We conclude that the RNF126/BAG6 complex contributes to G0S2 degradation and that interventions to prevent G0S2 degradation may offer a therapeutic strategy for managing ischemic diseases.

Hypokalemic periodic paralysis associated with hypophosphatemia in a patient with hyperinsulinemia

A 34-year-old man was admitted to the hospital because of acute quadriplegia. On admission, serum potassium was 2.1 mEq/L and serum inorganic phosphate was 1.4 mg/dL. Thyroid function was normal. Serum levels of aldosterone, cortisol, and intact parathyroid hormone were normal. Fasting plasma glucose was 109 mg/dL, and fasting serum insulin was 25.0 U/mL. Shortly after intravenous supplementation of potassium, muscle strength was normalized. Oral glucose tolerance test revealed impaired glucose tolerance and hyperresponse of insulin. During the oral glucose tolerance test, serum potassium and phosphate decreased significantly. These findings suggest that hyperinsulinemia and insulin-induced transmembrane shift of extracellular potassium and phosphate may have been involved in the abnormalities of serum electrolytes and development of hypokalemic periodic paralysis in the present patient.

Repeated cycles of G-CSF-combined postremission chemotherapy for acute myeloid leukemia in a first complete remission: a pilot study

The cure rate of acute myeloid leukemia might increase if G-CSF were given concurrently with repeated postremission chemotherapy. However, this therapy might cause severe complications, including depletion of normal hematopoietic progenitors as a long-term toxicity. Thus, we conducted a pilot study of this strategy. Twenty-six acute myeloid leukemia patients in a first complete remission (CR) were treated with two courses of consolidation chemotherapy (10-day BHAC-DMP, consisting of behenoyl cytosine arabinoside, daunorubicin, 6-mercaptopurine and prednisolone) and repeated maintenance-intensification therapy including eight cycles of six-day BHAC-DMP. G-CSF (filgrastim) was administered concurrently with these BHAC-DMP therapies. Toxicity during the therapeutic period was not significant in the study group compared with the historical control, treated with the same regimen without G-CSF. Neutrophil recovery after the consolidation therapy was more rapid in the study group than in the historical control (p = 0.066 and 0.024 for the first and second consolidation courses, respectively). Long-term toxicity, such as cytopenia, has not been seen in eight patients who have remained in CR for a long period (range: 39-58 months). At a median follow-up of 39 months, the predicted rate of 42-month CR duration for these 26 patients was 50% (95% confidence limits: 30% to 71%). We conclude that G-CSF-combined repeated BHAC-DMP postremission therapy is feasible. Full elucidation of the clinical benefit of this strategy will require further study.

Pulmonary toxicity after granulocyte colony-stimulating factor-combined chemotherapy for non-Hodgkin's lymphoma

Sporadic cases have developed pulmonary toxicity after receiving chemotherapy and granulocyte colony-stimulating factor (G-CSF). However, because such cases received chemotherapy that alone frequently causes pulmonary toxicity, the role of G-CSF in this toxicity has been unclear. CHOP therapy (cyclophosphamide, doxorubicin, vincristine and prednisolone) only slightly induces pulmonary toxicity. However, we observed a considerable incidence of this toxicity in non-Hodgkin's lymphoma subjects receiving CHOP therapy and G-CSF (6 out of 52 subjects, 11.5%). In this cohort, among various characteristics, including the dose and interval of CHOP therapy, only the mean peak leucocyte count (MPLC) with each therapy cycle was associated with development of this toxicity (MPLC > or = 23.0 x 10(9) l(-1), 6 out of 29 cases; MPLC < 23.0 x 10(9) l(-1), 0 out of 23 cases; P = 0.020). These findings suggest that the effect of G-CSF is the main determinant of the pulmonary toxicity in these cases. Because the toxicity was associated with a large MPLC and did not recur in cases readministered G-CSF, an idiosyncratic reaction to G-CSF is unlikely to be the pathogenesis of this toxicity. Thus, lowering the G-CSF dose seems to be useful in the prevention of this toxicity. In all six cases, the time course of manifestation of the toxicity was the same, and early application of high-dose corticosteroid led to cure. This knowledge will be helpful in the care of similar cases.

Spontaneous healing of pancreatic abscess after fistulization to the duodenal bulb

A 70-year-old man was admitted to the hospital because of sudden, upper abdominal and back pain. Laboratory and image data indicated acute pancreatitis. Shortly after the admission, pancreatic and liver abscess with bacteremia developed. Antibiotic therapy seemed effective. A month later, spontaneous fistulization of the pancreatic abscess to the duodenal bulb was found by gastroduodenal fiberscopy. Injection of contrast medium into the duodenal orifice showed that the fistula was draining the abscess and that no other fistula formed from the abscess. Endoscopic retrograde cholangiopancreatogram indicated no fistula formation to the pancreatic duct. The pancreatic abscess became smaller and was not visible using computerized tomography and ultrasonography 3 months later and thereafter. Closure of the duodenal orifice was ascertained by the endoscopy. It is suggested that retrograde infection from the fistula was prevented by the single fistulization to the acidic duodenal bulb, which is not supposed to allow most bacterial growth. Pancreatic abscess usually necessitates operative treatment, even with fistulization to the alimentary tract. It seems likely that the single, small fistulization to the bulb, in addition to the lack of underlying disease and medical and nutritional support, facilitated the spontaneous healing process.

Cell cycle modulation by hematopoietic growth factors in myelodysplastic syndromes: analysis by three-color flow cytometry

Investigations of the effects of hematopoietic growth factors (HGFs) on the cell cycle of cells from myelodysplastic syndrome (MDS) have been hampered by technical difficulties. In this study, using a recently established flow cytometric method that enables detailed analysis of the cell cycle (Gzero-, G1-, S-, and G2/M-phases) of target cells in a heterogeneous cell population, we examined the effects of granulocyte colony-stimulating factor (G-CSF) and other HGFs on the cell cycle of CD13-positive cells (blasts and other malignant myelocytic and monocytic cells) in MDS. The cell cycle response to G-CSF (decrease in Gzero-phase cells and increase in S-phase cells) was heterogeneous among MDS cases. When the data for 13 MDS cases and 15 de novo AML cases were compared statistically, the magnitude of cell cycle activation by G-CSF was weaker for the cells from the MDS cases. Stem cell factor, interleukin-3, or a combination of these HGFs with G-CSF reduced the Gzero-phase cell percentage in all examined MDS cases whose cell cycle was unresponsive to G-CSF alone. When cytosine arabinoside was added to cells with or without stimulation by HGFs, the viable G0-phase cell count was reduced in HGF-stimulated cells compared with unstimulated cells in seven of eight cases. The present results suggest that G-CSF-induced cell cycle stimulation of malignant cells can be expected in a fraction of MDS patients and that even in MDS patients whose cells do not respond to G-CSF, employment of other HGFs and their combination with G-CSF is worth consideration. The results also suggest that a well-designed therapy using HGFs and chemotherapeutic drugs may reduce the quiescent (Gzero) cell count in MDS, which is assumed to be responsible for drug resistance derived from cell kinetics.

Plasma soluble interleukin-2 receptor level in patients with primary myelodysplastic syndromes: a relationship with disease subtype and clinical outcome

To assess the hypothesis that the plasma soluble interleukin-2 receptor (sIL-2R) level may have predictive value for morbidity/mortality in patients with myelodysplastic syndromes (MDS), we determined in plasma sIL-2R level of 80 MDS patients and examined their subsequent clinical course. Compared with low-risk MDS (refractory anaemia (RA) and RA with ringed sideroblasts) patients and normal subjects, the plasma sIL-2R level was significantly elevated in high-risk MDS (three other MDS subtypes and acute leukaemia following MDS) patients (high-risk MDS versus low-risk MDS, P < 0.01; high-risk MDS versus normal subjects, P < 0.01). 14/40 low-risk MDS patients developed at least one of the following during the follow-up period: erythrocyte transfusion dependence, infections requiring hospitalization, disease progression or MDS-related death. The plasma sIL-2R level was higher in these eventful subjects than in event-free low-risk subjects (P < 0.0001), and all of 10 low-risk subjects with a plasma sIL-2R level > 540 U/ml experience at least one event. By logistic regression analysis of various parameters in these 40 low-risk subjects, the plasma sIL-2R level was identified as the strongest independent parameter for predicting eventful subjects (P < 0.0047). The plasma sIL-2R level did not show a predictive value in high-risk MDS. This study revealed that the plasma sIL-2R level is significantly elevated in high-risk MDS and suggested that the plasma sIL-2R level is a valuable predictive factors for the clinical outcome in low-risk MDS.

Autoimmune hemolytic anemia in patients with de novo acute myelocytic leukemia

Autoantibody against erythrocytes has occasionally been observed in patients with de novo acute myelocytic leukemia (AML). However, it is not clear whether this autoantibody in AML patients induces frank hemolysis (autoimmune hemolytic anemia, AIHA), as seen in lymphoid neoplasms. We present two de novo AML patients who showed hemolysis due to antiglobulin test-positive and test-negative AIHA, respectively. AIHA should be considered as one cause of anemia in de novo AML patients, and blood transfusions should be given carefully in such cases to avoid harmful hemolysis.

Renal refractoriness to phosphaturic action of parathyroid hormone in a patient with hypomagnesemia

A 50-year-old tetanic woman with hypomagnesemia is described. She had partial resection of the stomach and the jejunum at the age of 20 years. Lack of parathyroid hormone (PTH) function was indicated by hypocalcemia, hyperphosphatemia and high tubular reabsorption of phosphate. However, both plasma concentration of PTH and nephrogenous cAMP were normal. Administration of magnesium sulfate completely normalized serum phosphate and tubular transport of phosphate with only a modest increase in nephrogenous cAMP. The present findings suggest that phosphaturic action of PTH is impaired in magnesium deficiency and that steps distal to cAMP production may be responsible for the renal refractoriness to the hormonal action.

Lineage-unrestricted hematologic response to granulocyte colony-stimulating factor in a patient with refractory anemia with excess blasts

We report a patient with refractory anemia with excess blasts who showed a lineage-unrestricted hematologic response to granulocyte colony-stimulating factor (G-CSF). After 17 months of a stable disease state, the patient developed pneumonia, progression of cytopenia, and reduced cellularity and blast mass in the bone marrow. He was given G-CSF to overcome the pneumonia. Not only the neutrophil count, but also the platelet count increased soon after initiation of the G-CSF therapy; both counts became normal on the fifth day of the G-CSF therapy. Additionally, the anemia improved gradually. The neutrophil and platelet counts were maintained in the normal range for 3 months after cessation of the G-CSF. In vitro studies showed that G-CSF alone stimulated megakaryocyte colony formation from bone marrow mononuclear cells (BMMNC), and accessory cells in the BMMNC were necessary for expression of this G-CSF-induced in vitro megakaryocytopoiesis. These results suggest that, in coordination with accessory cells, G-CSF stimulated megakaryocytopoiesis in the patient. This case provides valuable information for understanding the mechanisms of a lineage-unrestricted hematologic response to G-CSF, which is very rarely observed in MDS.

Defective natural killer (NK) cell-mediated cytotoxicity does not imply clonal involvement of NK cells in myelodysplastic syndromes

The clonality of purified cells was examined in 10 myelodysplastic syndromes (MDS) patients by analysing the restriction fragment length polymorphism and methylation pattern of the phosphoglycerate-kinase gene. Natural killer (NK) cell-mediated cytotoxicity was also examined. The granulocytes and monocytes were monoclonal or oligoclonal in all cases, except for the monocytes in one case. Conversely, the NK and T cells had a polyclonal pattern in most cases, including all cases who had defective NK cell-mediated cytotoxicity. The hypothesis that reduced NK cell-mediated cytotoxicity in MDS is caused by a clonal involvement of NK cells was not supported by the present study.

Possible gliclazide-induced water retention with azotemia

An 80-year-old woman with diabetes mellitus was treated with gliclazide. Prior to the gliclazide administration, her urinary excretion of albumin, serum urea nitrogen and serum creatinine were normal. After the medication, oliguria, edema and azotemia developed. On the twenty-fourth day when the edema was severe and generalized, gliclazide administration was terminated. On the following day urinary volume increased suddenly (5,740 ml/day). Polyuria persisted for five days. Edema improved and urea nitrogen and creatinine were normalized thereafter. Though the mechanism is not known, the clinical course suggests that gliclazide is the principal causative factor in the water retention and azotemia in this patient.

Case report: silent thyroiditis developed during alpha-interferon therapy

Alpha-interferon (IFN-alpha) was used for the treatment of chronic active hepatitis C in a 30-year-old woman who was euthyroid but had low titers of antithyroid antibodies before treatment. Two months after the initiation of IFN-alpha therapy she became thyrotoxic. She had nontender diffuse goiter. A laboratory examination revealed elevated levels of serum free thyroid hormones and a suppressed concentration of serum thyrotropin. Titers of antimicrosomal antibodies increased. The anti-thyrotropin receptor antibody was negative. A 99mTcO- scintigram of the thyroid showed reduced uptake. During the IFN therapy free thyroid-hormone levels started to decline. The IFN-alpha therapy was completed 1 month after the onset of thyrotoxicosis. Two months after the completion of the therapy the patient became euthyroid and 99mTcO- uptake was normalized. It is likely that preexisting chronic thyroiditis was exacerbated to cause silent thyroiditis during IFN-alpha therapy. None of the other 11 patients with chronic hepatitis C who had had no anti-thyroid antibodies and were treated with IFN-alpha showed anti-thyroid antibodies and thyroid dysfunction after the therapy. It is advisable to assess anti-thyroid antibodies and thyroid function in patients who are going to receive IFN-alpha treatment.

A case of rheumatoid arthritis associated with silent thyroiditis

A 41-year-old female with rheumatoid arthritis had nontender enlarged thyroid gland. Thyroid function tests revealed increased concentrations of serum free T3 (FT3, 10.8 pmol/L) and free T4 (FT4, 31.1 pmol/L) with suppressed concentration of thyrotropin (TSH, lower than 0.1 mU/L) and low 24-hour thyroidal radioactive iodine uptake (1.6%). Serum thyrotropin receptor antibody (TRAb) was negative (0%) and she had positive anti-thyroglobulin and anti-microsomal antibodies. A diagnosis of silent thyroiditis was made based on laboratory findings. Serum concentrations of FT3 and FT4 normalized one month later without treatment. The causal relationship between the two diseases is discussed.

Differential regulation of multiple c-erbA expression by thyrotropin, insulin and insulin-like growth factor I in rat thyroid FRTL-5 cells

Regulation of multiple c-erbA gene expression was studied in rat thyroid FRTL-5 cells. Two species of erbA alpha (alpha 1 and alpha 2) mRNA and one species of erbA beta (beta 1) mRNA were identified by Northern blot analysis. Withdrawal of thyrotropin (TSH), insulin and serum from the complete medium resulted in an increase in alpha 1 and alpha 2 erbA mRNA levels without altering the level of erbA beta 1 mRNA. Readdition of TSH, N6,2'-O-dibutyryl cAMP or forskolin caused a transient reduction of alpha 1 and alpha 2 mRNA levels (75-90%) at 3-12 h. The alpha 1 and alpha 2 mRNA levels were restored at 24 h. The TSH action was dose-dependent showing the half-maximal effect at around 10(-9) M. Readdition of TSH did not show any effect on beta 1 mRNA level. The action of TSH was not dependent on ongoing protein synthesis but required ongoing transcription. Inhibitors of thyroid hormone biosynthesis, propylthiouracil and methylmercaptoimidazole, did not show any effect on TSH action. Readdition of insulin or insulin-like growth factor I (IGF-I) caused a dose-dependent reduction of alpha 1 and alpha 2 mRNA levels without any effect on beta 1 mRNA level. Their action was slower than TSH and persistent. The actions of insulin and IGF-I were dependent on both ongoing translation and transcription. These results indicate that TSH and insulin/IGF-I reduce levels of c-erbA alpha 1 and alpha 2 mRNA possibly by two distinct mechanisms without altering c-erbA beta 1 mRNA level in FRTL-5 cells.

Thyroid hormone metabolism and nuclear binding in Gunn rats

We examined the serum concentrations of total, free thyroid hormones and TSH, activity of hepatic T4 5'-deiodinase, and T3 binding to hepatic nuclei in homozygous (j/j) and heterozygous (j/+) Gunn rats. Both total T3 and free T3 (FT3) concentrations in sera from j/j rats were significantly lower than those of j/+ rats on 5-10, 15-20, and 25-30 days after birth. Both total T4 and free T4 (FT4) concentrations in j/j and j/+ rat sera were not significantly different on 5-10 days. However, in j/j rats they were significantly higher than those of j/+ rats on days 15-20 and 25-30. Serum reverse T3 (rT3) concentrations were higher in j/j than in j/+ rats on days 5-10, 15-20, and 25-30. Serum TSH concentration in j/j and j/+ rats on 15 days post-natal were 1.42 +/- 1.28 and 1.65 +/- 1.24 micrograms/l (mean +/- SD), respectively, which were not significantly different from each other. T3 formation from T4 in hepatic microsomal fractions obtained 15 days after birth was significantly lower in homozygotes than in heterozygotes (4.89 +/- 1.18 vs 11.15 +/- 2.38 pmol/mg protein/min, p less than 0.005). Binding constants (Ka) as well as maximal binding capacities (MBC) for T3 of hepatic nuclei from 15 day-old j/j and j/+ rats were similar (ka; 3.58 x 10(9) vs 3.15 x 10(9) M-1, MBC; 0.316 vs 0.380 pmol/mg DNA). From these results we suggest that decreased conversion from T4 to T3 is one of the major reasons for high serum levels of T4 and rT3, and low levels of T3 in j/j rats, and that nuclear T3 binding and pituitary TSH secretion are unaltered in j/j rats.

The deoxyribonucleic acid regions involved in the hormonal regulation of thyroglobulin gene expression

Transcription of the thyroglobulin (TG) gene is stimulated by TSH via cAMP. We have characterized the sequence elements responsible for the hormone-dependent expression of TG gene in rat thyroid FRTL-5 cells using internal deletion and linker-scanning mutants of the minimal TG promoter (-170 basepairs) fused with the bacterial chloramphenicol acetyltransferase reporter gene. The TG gene is regulated by at least two regions located between -165 and -140 bp (TG-III) and between -95 and -65 bp (TG-I) from the transcription initiation site. The intervening region can be deleted without significant effect on the promoter activity. Either of the two regions alone does not promote hormone-dependent transcription. A DNase footprinting assay showed that TG-I and TG-III are the principal protein-binding sites and that the proteins interacting with these two regions are induced by TSH or cAMP. These results suggest that the hormone-dependent expression of TG gene may be achieved by cooperative interaction of the proteins bound to TG-I and TG-III.

Similar nuclear factors mediate stimulation of rat thyroglobulin gene transcription by thyrotropin and insulin-like growth factor-I

Transcription of the thyroglobulin (TG) gene in rat thyroid FRTL-5 cells is stimulated by two hormones, TSH and insulin-like growth factor-I (IGF-I). The effect of TSH is mimicked by cAMP. Promoter regions of the rat TG gene responsible for hormonal action as well as the nuclear regulatory proteins that interact with these regions were characterized. Minimal promoter that responds to both hormones has been found to be up to -171 basepairs from the transcription initiation site. In DNase-I footprinting analysis, nuclear extracts from cells treated with either of these hormones protected the same two major regions within the minimal promoter. Mutations in these two regions abolished basal, TSH-stimulated, as well as IGF-I-stimulated expression of the fused reporter gene chloramphenicol acetyltransferase. DNA mobility shift assay revealed that cAMP and IGF-I induce binding of similar nuclear proteins to these promoter regions. These results suggest that rat TG gene transcription is regulated by the convergent action of two distinct signaling pathways, possibly involving similar DNA-binding nuclear proteins and regulatory sequences of the TG gene promoter.

Thyroxine binding to human serum albumin immobilized on sepharose and effects of nonprotein albumin-binding plasma constituents

125I-thyroxine (125I-T4) binding to human serum albumin (HSA) covalently attached onto CNBr-activated Sepharose (HSA-Sepharose) was studied. 125I-T4 binding to HSA-Sepharose was rapid and saturable. Nonlinear curve-fitting analysis of binding isotherms revealed two classes of binding sites. The values of dissociation constants of high and low affinity sites were 2.19 +/- 0.53 x 10(-6) M and 2.69 +/- 0.78 x 10(-5) M, respectively. The number of binding sites of the high and the low affinity sites were 1.28 +/- 0.46 mol/mol and 23.5 +/- 9.7 mol/mol of HSA, respectively. Fatty acids and bilirubin competitively inhibited the high-affinity binding of 125I-T4 to HSA-Sepharose without affecting the low-affinity binding. 8-anilino-1-naphthalene sulfonic acid (ANS) inhibited the high affinity T4 binding via reduction of the binding capacity. Unlabeled T4 showed little inhibition of ANS binding to HSA, as measured by fluorescence intensity. These results suggest that ANS allosterically inhibits the high-affinity T4 binding to HSA-Sepharose.

Thyroid hormone autoantibodies (THAA) in three sisters: a four-year follow up

We have found three sisters who had thyroid hormone autoantibodies (THAA) in serum. Two of them were hypothyroid due to Hashimoto's thyroiditis. They were treated with synthetic thyroxine (T4) (Case 1) or T4 and triiodothyronine (T3) (Case 2). The other sister (Case 3) was euthyroid throughout the investigation period. Changes in the titers of THAA, antithyroglobulin (Tg) antibodies as well as in the concentrations of thyrotropin (TSH), and total and free thyroid hormones (T3, T4, FT3, and FT4) in sera from each patient were examined for four years. A significant positive correlation was observed between titers of THAA and anti-Tg antibodies in both Case 1 (anti-T3 and anti-T4) and 2 (anti-T4). On the other hand, a significant negative correlation between titers of anti-T3 and anti-Tg antibodies was observed in Case 3. These results suggest that antigen of THAA might be Tg in Case 1 and 2 and mechanism(s) of the production of THAA of Case 1 might be different from that of Case 1 and 2 in terms of their antigen or immune recognition of Tg.

[A case of pseudo-Bartter's syndrome associated with hypokalemic myopathy]

A case of pseudo-Bartter's syndrome associated with hypokalemic myopathy was presented. A 37-year-old housewife was admitted to our hospital because of muscle cramps with muscle weakness and tetany. There was a history of facial edema and constipation, which have been managed with "Kanpo medicine (Chinese medicine)" and laxatives for several years. The patient was amenorrhea 3 months before entry. She began to experience muscle weakness and muscle cramps associated with gait disturbance 2 or 3 months before admission. On physical examination, she was thin with positive Trousseau's and Chvostek's signs. Laboratory studies revealed hypokalemia, low urinary excretion of potassium, hypocalcemia, metabolic alkalosis, elevated creatine phosphokinase (CPK), increased levels of plasma renin activity and plasma aldosterone concentration, and decreased sensitivity to pressor effect of angiotensin II. Potassium supplementation resulted in restoration of her symptoms and normalization of low serum calcium and elevated CPK levels. She was diagnosed to be pseudo-Bartter's syndrome due to anorexia nervosa. The mechanism(s) of hypokalemia in our case was discussed.

Evidence for disulfide bonds in membrane-bound and solubilized opioid receptors

The effects of pretreatment with dithiothreitol (DTT) on opioid binding activities of membrane-bound and digitonin-solubilized opioid receptors from bovine adrenal medulla were studied. Pretreatment of membranes with DTT or mercaptoethanol inhibited [3H]diprenorphine binding by reducing the number of binding sites. The inhibitory action of DTT was time and dose dependent. The binding of [3H]D-Ala2-D-Leu5-enkephalin was also inhibited by DTT pretreatment. Pretreatment of digitonin-solubilized binding sites with DTT also reduced the number of [3H]diprenorphine binding sites. The action of DTT was diminished by preincubating the DTT solution with H2O2. [3H]Diprenorphine protected the opioid binding sites from the inhibitory action of DTT. The present results provide evidence that disulfide bonds are implicated in opioid binding activity of the opioid receptor system.

Solubilization of adrenal medullary opioid receptors

The opioid-binding activity of digitonin extract of bovine adrenal medullary membranes was studied. [3H]Diprenorphine binding to the solubilized material was rapid and saturable. The dissociation constant of [3H]diprenorphine binding was 0.76 nM. Several opioids displaced the [3H]diprenorphine binding. The complex of [3H]diprenorphine and the solubilized binding sites was eluted as a single peak on a Sepharose 6B column and showed an apparent molecular weight of 200,000. These results indicate that active opioid receptors are solubilized with digitonin from bovine adrenal medullary membranes.

Phospholipid/Ca2+-dependent protein kinase activity in human parathyroid adenoma

We have examined the activities of phospholipid/Ca2+-dependent and cyclic AMP-dependent protein kinases of the parathyroid adenomas and the atrophic glands which were resected from three patients with primary hyperparathyroidism. Phospholipid/Ca2+-dependent protein kinase activity of atrophic parathyroid gland was exclusively present in cytosol fraction (90.7 +/- 12.3%). On the other hand, phospholipid/Ca2+-dependent protein kinase activity of parathyroid adenomas was 66.9 +/- 6.4% in cytosol and 33.1 +/- 6.4% in membrane fraction, suggesting a translocation of the enzyme from the cytosol to the membranes. Cyclic AMP-dependent protein kinase activity appeared to be higher in parathyroid adenoma than in atrophic parathyroid gland in both cytosol and membrane fractions.

[Characterization of adrenal medullary opioid receptors. II. Coupling of adrenal medullary opioid receptors to GTP binding proteins]

We studied possible coupling of opioid receptors to GTP-binding proteins to clarify the mechanism(s) of opioid action in bovine adrenal medullary membranes. Guanylyl imidodiphosphate (Gpp(NH)p) reduced the binding of [3H] D-Ala2-D-Leu5-enkephalin ([3H] DADLE) to bovine adrenal medullary membranes dose-dependently, and enhanced the binding of [3H] diprenorphine to them. Gpp(NH)p (0.1 mM) enhanced the Kd value of the [3H] DADLE binding from 2.9 nM to 3.9 nM, but did not change its Bmax. Pretreatment of bovine adrenal medullary membranes with pertussis toxin (PT) reduced the [3H] DADLE binding. The Gpp(NH)p inhibition for [3H] DADLE binding was diminished by the PT-pretreatment. On the other hand, the [3H] diprenorphine binding to PT-pretreated membranes was higher than that to control membranes. Levorphanol inhibited the adenylate cyclase activity of the rat caudate nucleus crude synaptosomal fraction, but did not change that of bovine adrenal medullary membranes. These results suggest that opioid receptors in bovine adrenal medullary membranes are coupled to PT-sensitive GTP-binding protein which may not influence on adenylate cyclase.

[Characterization of adrenal medullary opioid receptors. I. Binding of opioids to adrenal medullary opioid receptors]

We studied the binding of [3H]D-Ala2-D-Leu5-enkephalin ([3H]DADLE) and [3H] diprenorphine to crude plasma membrane fraction obtained from the bovine adrenal medulla (bovine adrenal medullary membranes) in order to characterize adrenal medullary opioid receptors. The [3H] diprenorphine binding was the highest in crude plasma membrane-mitochondrial fraction among all subcellular fractions studied. The amount of [3H] diprenorphine bound to bovine adrenal medullary membranes was proportional to the protein concentration. Association kinetics of the [3H] diprenorphine binding to bovine adrenal medullary membranes showed that the maximal binding was achieved following 8 min incubation and that the binding conformed the second-order kinetics. [3H] DADLE and [3H] diprenorphine bound to bovine adrenal medullary membranes with high affinities. The Kd and Bmax for the [3H] DADLE binding were found to be 2.9 nM and 57.5 fmole/mg protein, respectively, while those for the [3H] diprenorphine binding were 0.31 nM and 250 fmole/mg protein, respectively. Displacement studies showed that the [3H] diprenorphine binding was inhibited dose-dependently by levorphanol, dynorphin (1-13), beta-endorphin and DADLE. Levorphanol was at least 1000-fold more potent to inhibit the [3H] diprenorphine binding than dextrorphan, indicating stereospecificity of the [3H] diprenorphine binding. Na+, Li+ and K+ (100 mM) diminished the [3H] DADLE binding and enhanced [3H] diprenorphine binding. Na+ (100 mM) increased the Kd value for the [3H] DADLE binding from 2.9 nM to 14.1 nM. Mn++, Ca++ and Mg++ diminished the [3H] diprenorphine binding. Mn++ (1 mM) increased the Bmax value for the [3H] DADLE binding from 95 fmole/mg protein to 450 fmole/mg protein. These effects of Na+ and Mn++ on the [3H] diprenorphine binding were found to be dose-dependent. [3H] Diprenorphine binding to the digitonin-solubilized opioid receptor was also inhibited dose-dependently by Mn++. These results suggest that bovine adrenal medullary membranes contain high affinity and stereospecific opioid receptors and that the binding of opioids to the bovine adrenal medullary opioid receptors is influenced by cations. Binding study also revealed the presence of opioid receptors in human malignant pheochromocytoma. The Kd and Bmax of the [3H] diprenorphine binding to crude membrane fraction obtained from malignant pheochromocytoma were found to be 0.14 nM and 10.4 fmole/mg protein, respectively.

Coupling of adrenal medullary opioid receptors to islet-activating protein-sensitive GTP-binding proteins

Possible coupling of bovine adrenal medullary opioid receptors to islet-activating protein (IAP, pertussis toxin)-sensitive GTP-binding proteins was investigated by studying effects of guanyl-5'-yl imidodiphosphate (Gpp(NH)p) and IAP treatment of membranes on opioid binding. Gpp(NH)p inhibited [3H]D-Ala2-D-Leu5-enkephalin ([3H]DADLE) binding by increasing the dissociation constant of [3H]DADLE and membranes, and enhanced slightly [3H]diprenorphine binding. IAP treatment of membranes reduced [3H]DADLE binding and abolished almost completely the Gpp(NH)p inhibition of [3H]DADLE binding. Treatment of membranes with IAP and [32P]NAD resulted in radio-labeling of membrane proteins of approximately 39,000 dalton. DADLE inhibited adenylate cyclase activity in rat brain caudate nucleus. However, DADLE, beta-endorphin, levorphanol and dynorphin A(1-13) did not show any significant inhibitory action on bovine adrenal medullary adenylate cyclase activity. These results suggest that bovine adrenal medullary opioid (DADLE) receptors are linked to IAP-sensitive GTP-binding proteins which are not directly coupled to adenylate cyclase.

Thyroid hormone autoantibodies (THAA) in two cases of Graves' disease: effects of antithyroid drugs, prednisolone, and subtotal thyroidectomy

Changes in titers of serum thyroid hormone autoantibodies (THAA) and anti-thyroglobulin (Tg) antibodies during treatment with antithyroid drugs (methimazole and propylthiouracil) were examined in two cases of Graves' disease. Effects of prednisolone and subtotal thyroidectomy were also investigated in one case (case 1). Initially both cases had only anti-T4 autoantibodies in their serum. During methimazole therapy, the titer of anti-T4 autoantibodies increased in both cases, and anti-T3 autoantibodies became detectable and their titer increased in case 2. The influence of propylthiouracil on the titer of THAA was not clear. Both prednisolone plus methimazole therapy and subtotal thyroidectomy decreased the level of anti-T4 autoantibodies in case 1. There was a significant correlation between titers of THAA and anti-Tg antibodies in both cases, although titers of anti-Tg antibodies in case 1 stayed within the normal range throughout the investigation period. These results indicate that methimazole treatment could induce and/or enhance the production of THAA and THAA are antibodies against thyroid hormone-containing Tg molecule.

Opioid and non-opioid binding of beta-endorphin to bovine adrenal medullary membranes

Binding of human beta-endorphin (beta h-EP) to bovine adrenal medullary membranes was characterized using [125I]Tyr27-beta h-EP [( 125I]beta h-EP) as a primary ligand. The specific binding of [125I]beta h-EP was time-dependent, saturable and stereospecific. Analysis of a saturation isotherm revealed two apparent classes of specific binding sites with dissociation constants of 2.4 and 34 nM. The extent of maximum inhibition of specific [125I]beta h-EP binding by either levorphanol, morphine, naloxone, dynorphin A (1-13) or D-Ala2-D-Leu5-enkephalin was similar to each other and remained partial (60-70%). Levorphanol eliminated the high affinity component but showed no effect on the low affinity component of [125I]beta h-EP binding. beta h-EP(1-31) displaced completely the [125I]beta h-EP binding. However, beta h-EP(1-23) only partially (approximately 80%) inhibited the [125I]beta h-EP binding. beta h-EP(6-31) showed inhibitory activity on [125I]beta h-EP binding. These results suggest that [125I]beta h-EP binding to bovine adrenal medullary membranes consists of a high affinity opioid-sensitive component and a low affinity non-opioid component. The non-opioid component of [125I]beta h-EP binding may be related to COOH-terminal of the beta h-EP molecule.

An improved and simplified method for the detection of thyroid hormone autoantibodies (THAA) in serum

We have developed and evaluated a new and simplified method for the detection of thyroid hormone autoantibodies (THAA) in serum. The method includes acidification of serum followed by adsorption of liberated thyroid hormones onto dextran-coated charcoal and then alkalinisation of the serum in assay buffer prior to performing a binding study. Using our method, specific binding of 125I-T4 to serum THAA in two patients with Hashimoto's thyroiditis was almost the same regardless of whether or not the sera had been preincubated with a large amount of cold T4. On the other hand, without the acid treatment, preincubation with cold T4 considerably inhibited the binding of 125I-T4 to serum THAA in both cases. These results indicate that serum THAA can be easily detected under conditions in which circulating thyroid hormones hardly affect the binding study by using our new sensitive method.

A case of total thyroxine-binding globulin deficiency with Graves' disease: fluctuations of plasma triiodothyronine/thyroxine ratio

A 37-year-old male with total thyroxine-binding globulin (TBG) deficiency associated with Graves' disease is described. Both TBG immunoreactivity and TBG capacity were not detectable in his serum. Serum concentrations of thyroxine-binding prealbumin and albumin were normal. He was initially hyperthyroid. During methimazole-treatment he was maintained in an euthyroid state except for two short hypothyroid periods. His plasma triiodothyronine/thyroxine (T3/T4) ratios during both the untreated hyperthyroid and the methimazole-induced hypothyroid states were higher than those during his methimazole-induced euthyroid state. These findings on changes in his T3/T4 ratio accompanying thyroidal dysfunction were qualitatively comparable with those in patients with Graves' disease with normal TBG levels: that both untreated hyperthyroid and methimazole-induced hypothyroid patients showed higher T3/T4 ratios than methimazole-induced euthyroid patients. These results may provide indirect evidence that changes in hormonal secretion and conversion that raise T3/T4 ratio can occur in thyroidal dysfunctions even in the complete absence of TBG.

Microcomputer-based nonlinear regression analysis of ligand-binding data: application of Akaike's information criterion

Akaike's information criterion (AIC) (Akaike, H., IEEE Trans. Automat. Contr. AC-19, 716-723 (1974)) was applied to estimate statistically the number of classes of binding sites from ligand-binding data. Several sets of data were analyzed by both the AIC method and the F-test method. Good agreement was obtained between results from both methods. The present results suggest that the AIC method can be a good alternative to the F-test to estimate the number of classes of sites.

A case of Graves' disease with anti-triiodothyronine antibodies

A case of Graves' disease with high serum thyroxine (T4) and low triiodothyronine (T3) levels which was therefore initially diagnosed as a T4-thyrotoxicosis is reported. Examination of the serum from the patient showed the presence of unusual protein which bound T3. It was later confirmed as IgG class anti-T3 antibodies. In addition to treatment with methylmercaptoimidazole (MMI), the patient was treated with prednisolone for 30 days (total amount 500 mg). Titers of anti-T3 antibodies in the sera were unchanged before and after prednisolone treatment. Our present case indicates that it is clinically important to bear the presence of autoantibodies in mind to account for a possible error in measuring T3 and T4 by radioimmunoassay (RIA). In the case that RIA determination gives an unexpectedly high or low T3 and/or T4 value, the presence of autoantibodies to them should be considered and a test for them is recommended.

Serum thyroglobulin concentration in normal pregnancy

We measured the levels of serum thyroglobulin (Tg) in 52 pregnant females at various stages and compared them with those of 15 age-matched nonpregnant females. Serum Tg was measured by a solid-phase immunoradiometric assay. In pregnant females, mean serum Tg levels at the first, second, early third, and late third trimesters were 8.4 (range; 1.3-18.0), 9.2 (1.7-25.6), 10.1 (1.8-22.8), and 12.1 ng/ml (5.3-25.2), respectively. The statistical comparison was made after logarithmic transformation of the data. The mean value only at the late third trimester was significantly higher than that of controls (mean; 6.0 ng/ml, range; 1.5-23.6), but each value was within the normal range. Although serum Tg levels have been reported to be high at the end of pregnancy, our results indicate that the Tg levels in females could be clinically interpreted without regard to the coexistence of pregnancy.

Theoretical consideration of the effects of dilution on estimates of free thyroid hormones in serum

When concentrations of free thyroid hormones in serum are measured by equilibrium dialysis, the serum sample is diluted by dialysis buffer, resulting in a new equilibrium for distribution of these hormones that differs from that in the original serum sample. We have derived a mathematical formulation, based on an equilibrium model for multiple ligands and multiple binding sites, to determine the effect of dilution on the concentrations of free hormones in serum. Computer simulations based on the formulation indicate that both free thyroxin (T4) and free triiodothyronine (T3) are decreased by dilution of serum, free T3 being affected more than free T4. This dilution-related decrease is more prominent in hyperthyroidism than in euthyroidism, and even more striking for sera in which binding capacities for thyroid hormones are decreased (e.g., in thyroxin-binding globulin deficiency or hypoalbuminemia). These simulations can provide a basis for minimizing experimental errors in the estimates of concentrations of free thyroid hormones by equilibrium dialysis.

Theoretical consideration of the effects of dilution on estimates of free thyroid hormones in serum

When concentrations of free thyroid hormones in serum are measured by equilibrium dialysis, the serum sample is diluted by dialysis buffer, resulting in a new equilibrium for distribution of these hormones that differs from that in the original serum sample. We have derived a mathematical formulation, based on an equilibrium model for multiple ligands and multiple binding sites, to determine the effect of dilution on the concentrations of free hormones in serum. Computer simulations based on the formulation indicate that both free thyroxin (T4) and free triiodothyronine (T3) are decreased by dilution of serum, free T3 being affected more than free T4. This dilution-related decrease is more prominent in hyperthyroidism than in euthyroidism, and even more striking for sera in which binding capacities for thyroid hormones are decreased (e.g., in thyroxin-binding globulin deficiency or hypoalbuminemia). These simulations can provide a basis for minimizing experimental errors in the estimates of concentrations of free thyroid hormones by equilibrium dialysis.

Serum thyroglobulin (Tg) concentration in healthy subjects: absence of age- and sex-related differences

Serum concentrations of thyroglobulin in healthy subjects were measured by a solid-phase immunoradiometric assay. The mean concentration of serum thyroglobulin in 53 healthy males was 5.0 ng/ml (1.0-25.9 ng/ml) and that of 57 healthy females was 5.2 ng/ml (1.0-27.7 ng/ml). Neither sex-related nor age-related change in the serum thyroglobulin level was observed.

[Physical dependence liabilities of butorphanol, a narcotic antagonist, and its main metabolites, norbutorphanol and hydroxybutorphanol]

After the intravenous injection of butorphanol or norbutorphanol in rats every 1 hr for 3 days, naloxone-induced body weight loss and withdrawal syndrome were observed to some degree. A slow-released emulsion containing each of the test drugs was injected subcutaneously in guinea-pigs, and naloxone was administered after 2 or 3 days. BT caused little jumping response even at a dose of 600 mg/kg, and the reaction was significantly weaker than that of pentazocine. No jumping responses were recognized in the cases of NB (600 mg/kg). In morphinized rats, the injection of BT or HB caused potent body weight loss, and these rats exhibited withdrawal syndrome which was more potent than that by pentazocine at the same dose. The body weight losses by the injection of NB and pentazocine were to the same degree, and these changes were significantly different from that of the saline control. BT inhibited the adenylate cyclase activity of the rat caudate nuclei, and the effect was weaker than that of pentazocine. NB showed a slight inhibition, and HB had no effect on the activity. These results suggest that the physical dependence liability of butorphanol is less than that of pentazocine, and the potent mu-antagonistic character of butorphanol is based on the liability. NB, a mu-agonist, makes dependence production possible. The ability of HB is negligible.

Diabetic gangrene in Japan: analysis of 487 cases

Diabetic gangrene was thought of as a rather rare complication in Japan. Since the first report in 1917, only 16 cases were reported up to 1945. However, the number of reports increased rapidly in the manner of a geometric series after 1965. Sex and age distributions of the syndrome in Japan corresponded closely with those of Western countries. A distinct tendency in the inducement of gangrene was found, i.e. thermal trauma had preceded 43.6% of the cases. This might be the result of the local habit of warming the feet using hot-water bottles or foot warmers. The number of patients with normal pulses in the affected extremities in Japan was distinctly higher compared with that reported in Western countries. But functional and morphological changes in large peripheral vessels were frequently demonstrated when more detailed examinations were conducted. The cause for the rapid increase in the incidence of diabetic gangrene has not been elucidated, but changes in lifestyle may be partly responsible. The most conspicuous change was the increase in meat and fat intake during the 1960's. The changes in total calorie, total protein or sugar intake over this period were inconspicuous. Changes in dietary habits seem to be responsible, but further research will be necessary to clarify the details.

[Production of antithyroid hormone antibodies. 2. Genetic control of the production of anti-human thyroglobulin and antithyroid hormone antibodies in mice immunized with human thyroglobulin]

Recently anti-thyroid hormone antibodies have been found in many cases of thyroidal and non-thyroidal disorders. However, the exact mechanism(s) of production of anti-thyroid hormone antibodies in these patients is so far obscure. Thyroxine (T4) and triiodothyronine (T3) are haptens and are not immunogenic in free form. In this respect, human thyroglobulin (HTg) has long been suggested as an antigen of the anti-thyroid hormone antibodies observed in them because it carries thyroid hormones on its surface. In our previous communication, we reported the production of anti-HTg antibodies and anti-thyroid hormone antibodies in two rabbits and various strains of mice immunized with HTg. In order to elucidate the gene(s) which controls the production of anti-HTg and anti-thyroid hormone antibodies, various strains of mice which have different H-2 and Igh allotypes were immunized with HTg. The titers of anti-HTg and anti-thyroid hormone antibodies were measured, and the locus (loci) which controls the immune response against them was determined. Our present investigation has revealed that the Ir-gene(s) which controls the production of anti-HTg and anti-T4 antibodies is located in the I-A subregion. Concerning the production of anti-T4 antibodies in mice, the presence of Ir-gene(s) outside of H-2 is also suggested. The significance of the genetic mechanisms controlling the immune response against thyroid hormones in various thyroidal disorders is discussed.

Age- and sex-related differences of serum thyroxine binding globulin (TBG) in healthy subjects

Serum concentrations of thyroxine binding globulin (TBG) were measured in healthy adult subjects aged 20-79 years (152 males and 148 females) by radioimmunoassay. In contrast to previous reports, there were no significant age-related differences in either sex. Significant sex-related differences were observed only in the fourth decade, being higher in females than males (P less than 0.01).

[Thyroid hormone autoantibodies in Hashimoto's disease and Graves' disease]

We previously reported the presence of thyroid hormone autoantibodies (THAA) in the sera from three (2 Hashimoto's thyroiditis, 1 Hashimoto's thyroiditis suspected) out of four sisters in a family and one patient with Graves' disease during treatment with methimazole (MMI). According to the investigations of the binding of labelled thyroid hormones, endogenous and/or therapeutic thyroid hormones interfered with their binding with THAA. This interference, however, was excluded when the sera were acidified with a 0.05M glycine-HCl buffer (pH 2.1) and all the liberated thyroid hormones were absorbed into dextrancoated charcoal. In this study, the specific binding of the tracer thyroid hormone to gamma-globulin was examined in hormone-stripped sera from patients with Hashimoto's disease (pretreatment n = 29; L-T4 treatment n = 9) and Graves' disease (pretreatment n = 21; MMI or propyl-thiouracil (PTU) treatment n = 22; MMI or PTU treatment after 131I therapy n = 8) under conditions in which the difference of the concentration of gamma-globulin in each case did not influence the binding. None of the patients examined had increased binding of 125I-T3 with their gamma-globulin. Elevated binding of 125I-T4 was found in sera obtained from 3 patients (2 pretreatment, 1 L-T4 treatment) with Hashimoto's disease and 7 patients (1 pretreatment, 4 MMI or PTU treatment, 2 MMI or PTU treatment after 131I therapy) with Graves disease. Seven (2 Hashimoto's disease, 5 Graves disease) out of these 10 patients with anti-T4 autoantibodies had antibodies against thyroglobulin (Tg) as measured by the hemagglutination method. Titers of anti-T4 autoantibodies and anti-Tg antibodies did not correlate. In Graves disease, anti-T4 autoantibodies were detected during the treatments in sera from 5 (3 MMI or PTU treatment, 2 MMI or PTU treatment after 131I therapy) out of 16 patients (10 MMI or PTU treatment, 6 MMI or PTU treatment after 131I therapy) who had anti-Tg antibodies. On the other hand, anti-T4 autoantibodies prior to the medication could not be found in sera from 5 patients with positive anti-Tg antibodies. From these results, it is suggested that antithyroid drugs and/or 131I therapy might induce the production of THAA in patients with Graves disease through the deterioration of immunological tolerance and/or through the modification of the Tg molecule.

[Evaluation on the interaction between thyroxine binding globulin (TBG) and thyroxine (T4) in healthy subjects and pregnant women]

A very simple method for the evaluation of the interaction between thyroxine binding globulin (TBG) and thyroxine (T4) has been developed and evaluated in 6 healthy subjects and 5 pregnant women. Rabbit anti-human TBG antiserum was precipitated with 50% ammonium sulfate followed by passing a DEAE-cellulose column. Immunoglobulin G (IgG) fraction thus prepared was covalently attached on a Sepharose CL-4B and used as an immunoadsorbent of serum TBG. After treatment with charcoal to remove endogeneous thyroid hormones, 10 microliter of sera from 6 healthy subjects and 5 pregnant women were incubated with 125I-T4 and various concentrations of cold T4 followed by immunoadsorption with anti-TBG-Sepharose, and association constants (Ka) between TBG and T4 were calculated in each subject using Scatchard's plot. The Ka value thus obtained in 6 healthy subjects was 1.47 X 10(8) M-1 (SD = 0.24), and in 5 pregnant women it was 0.82 X 10(8) M-1 (SD = 0.21) which was significantly lower than that of healthy subjects (P less than 0.001). Our present method does not need purification of TBG from serum to investigate its functions, especially in relation to the binding with thyroid hormones. Also, only a very small amount (100 approximately 150 microliter) of serum is enough for the calculation of Ka between T4 and TBG. The whole procedure is very easy to perform and can be done in a relatively short time, and therefore we consider this method clinically relevant and useful.

Genetic control of mouse antibody production to human thyroglobulin

Genetic control of immune responses in mice against human thyroglobulin was studied using the enzyme-linked immunosorbent assay and passive haemagglutination test. Our results revealed that mice of H-2a, H-2d, H-2q, H-2k and H-2r haplotypes were high responders for antibody production to human thyroglobulin, while mice of H-2b and H-2s haplotypes were low responders. High responsiveness to human thyroglobulin was transmitted to F1 mice in a dominant fashion. Study of the genetic mapping of the immune responses to human thyroglobulin using various congenic mice showed that I-A subregion gene(s) control the immune response to human thyroglobulin.