A radioimmunoassay for measurement of 3,3'-diiodothyronine sulfate: Studies in thyroidal and nonthyroidal diseases, pregnancy, and fetal/neonatal life

Data suggesting that (1) sulfation of the phenolic hydroxyl of iodothyronines plays an important role in thyroid hormone metabolism and (2) maternal serum 3,3'-diiodothyronone sulfate (3,3'-T(2)S) may reflect on the status of fetal thyroid function stimulated us to develop a radioimmunoassay (RIA) for measurement of T(2)S. Our T(2)S RIA is highly sensitive, practical, and reproducible. T(4)S, T(3)S, and T(1)S crossreacted 3.1%, 0.81%, and 5.3%, respectively; thyroxine (T(4)), triiodothyronine (T(3)), and reverse (r)T(3), 3,3'-T(2) and 3'-T(1) crossreacted <0.1%. Although rT(3) sulfate (rT(3)S) crossreacted 55% in 3,3'-T(2)S RIA, its serum levels are very low and have little influence on serum T(2)S values reported here. T(2)S was measured in ethanol extracts of serum, amniotic fluid, and urine. Recovery of nonradioactive T(2)S added to serum was 96%. The dose-response curves of inhibition of binding of (125)I-T(2)S to anti-T(2)S by serial dilutions of ethanol extracts of serum or urine were essentially parallel to the standard curve. The detection threshold of the RIA varied between 0.17 and 0.50 nmol/L (or 10 and 30 ng/dL). The coefficient of variation (CV) averaged 9% within an assay and 13% between assays. The serum concentration of T(2)S was [mean +/- SE, nmol/L] 0.86 +/- 0.59 in 36 normal subjects, 2.2 +/- 0.06 in 10 hyperthyroid patients (P <.05), 0.73 +/- 0.10 in 11 hypothyroid patients (not significant [NS]), 6.0 +/- 1.5 in 16 patients with systemic nonthyroidal illness (P <.001), 18 +/- 2.5 in 16 newborn cord blood sera (P <.02), 2.7 +/- 0.32 in 25 pregnant women [15 to 40 weeks gestation, P <.001], 0.94 +/- 0.10 in 10 hypothyroid women receiving T(4) replacement therapy (NS), and 2.0 +/- 0.38 in 11 hypothyroid women treated with T(4) replacement and oral contraceptives (P <.02); serum T(2)S levels in the third trimester of pregnancy were similar to those in the second trimester of pregnancy. T(2)S concentration in amniotic fluid was 12.5 +/- 2.7 nmol/L (n = 7) at 15 to 20 weeks gestation, and it decreased markedly to 3.3 +/- 1.3 nmol/L (n = 3) at 35 to 38 weeks gestation. Urinary excretion of T(2)S in random urine samples of 19 normal subjects was 10.9 +/- 1.3 nmol/g creatinine. (1) T(2)S is a normal component of human serum, urine, and amniotic fluid, and serum T(2)S levels change substantially in several physiologic and pathologic conditions; (2) high serum T(2)S in pregnancy may signify increased transfer of T(2)S from fetal to maternal compartment, estrogen-induced increase in T(2)S production, decreased clearance, or a combination of these factors. The data do not support the notion that fetal thyroid function is the only or the predominant factor responsible for high serum T(2)S in pregnant women.     

Can two-dimensional echocardiography and Doppler color flow mapping identify the need for tricuspid valve repair?

Tricuspid regurgitation severity was assessed preoperatively with Doppler color flow mapping and these assessments were compared with surgical findings in 90 patients undergoing mitral or aortic valve replacement, or both. Group I (n = 52) required tricuspid valve annuloplasty because tricuspid regurgitation was judged intraoperatively to be severe; in Group II (n = 38), tricuspid valve annuloplasty was not performed because tricuspid regurgitation was judged intraoperatively not to be severe. With use of the apical four chamber and parasternal short-axis imaging planes, the severity of tricuspid regurgitation by Doppler color flow mapping was assessed by comparing the maximal area of tricuspid regurgitant signals with the right atrial area taken in the same frame in which the maximal tricuspid regurgitant signals were noted. This ratio was found to be greater than or equal to 34% (mean 50.2 +/- 11.8%) in 50 (96%) of 52 patients in Group I and less than 34% (mean 27.5 +/- 6.9%) in 36 (95%) of 38 patients in Group II (p less than 0.001). The maximal diastolic tricuspid anulus diameter measured with the same two-dimensional imaging planes was greater than or equal to mm/m2 body surface area (mean 26.7 +/- 5.2 mm/m2) in 46 patients (88%) in Group I and less than 21 mm/m2 (mean 17.8 +/- 2.5 mm/m2) in 36 patients (95%) in Group II (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Fatal atypical mycobacterial infection in a cardiac transplant recipient.

A 37-year-old female underwent heart transplantation for giant cell myocarditis. The patient died within three-and-a-half months of cardiac transplantation. Postmortem specimens from the heart and lung showed multiple necrotizing granulomas with numerous acid-fast bacilli. Polymerase chain reaction done on both the postmortem samples confirmed the presence of atypical mycobacterial infection. This fatal case of atypical mycobacteriosis in a cardiac transplant patient is reported for its rarity.     

3'-5'-Diiodothyronine in health and disease: studies by a radioimmunoassay.

A simple, reproducible, and highly specific RIA has been developed for measurement of 3',5'-diiodothyronine ((3',5'-T2) in unextracted serum. Interference in binding of radioactive 3',5'-T2 to anti-3',5'-T2 by serum proteins was minimized by using 0.4 M phosphate buffer (pH 6.2) and merthiolate. The detection threshold of the RIA was 2.5 ng/100 ml. Recovery of nonradioactive 3',5'-T2 added to serum averaged 99%. T4, T3, and rT3 cross-reacted with 3',5'-T2-binding sites on anti-3',5'-T2 antibody only to the extent of 0.0025, less than 0.0004, and 0.22%, respectively. 3'-Monoiodothyronine cross-reacted 1.7%. Serum 3',5'-T2 concentrations were (mean +/- SD) 6.4 +/- 2.4 ng/100 ml in 53 normal subjects, 4.2 +/- 3.5 ng/100 ml in 7 hypothyroid patients, 14.9 +/- 7.7 ng/ml in 25 patients with hepatic cirrhosis, and 14.3 +/- 5.3 ng/100 ml in 31 newborns' cord blood sera. The values in each of the latter four groups were significantly different from normal. The mean serum 3',5'-T2 concentration of 7.7 +/- 2.5 ng/ml in eight subjects in the third trimester of pregnancy did not differ significantly from normal at a time when serum T4 and T3 were clearly elevated. Oral administration of 300 microgram rT3 to 9 normal subjects led to a mean maximal increase in serum 3',5'-T2 concentration of 45% at 1 h. Total fasting in 3 obese subjects was associated with a significant increase in serum 3',5'-T2 from 8.6 to 16.3 ng/100 ml at 6-8 days; serum rT3 increased similarly, while serum T3 decreased and T4 did not change. Administration of dexamethasone (2 mg also associated with nearly parallel increases in serum 3',5'-T2 and rT3 and a decrease in serum T3. 3',5'-T2 concentrations were also measured in amniotic fluids at different stages of gestation; the mean value of 15.2 ng/100 ml at 15-20 weeks gestation was significantly higher than that of 5.8 ng/ml at 33-40 weeks gestation. Pronase hydrolysates of 9 autopsy specimens of normal thyroid glands contained (mean +/- SD) 350 +/- 144 microgram T4 and 0.24 +/- 0.15 microgram 3',5'-T2/g wet wt. On the basis of these data and those available for MCRs of 3',5'-T2 and T4, it was estimated that thyroidal secretion contributes less than 1% of 3',5'-T2 measured in serum of normal man. The various data suggest that: 1) 3',5'-T2 is a normal component of human serum; 2) almost all 3',5'-T2 in human serum derives from extrathyroidal sources; and 3) changes in serum 3',5'-2 generally parallel those in rT3.     

Rates of sustained virological response 12 weeks after the scheduled end of direct‐acting antiviral (DAA)‐based hepatitis C virus (HCV) therapy from the National German HCV registry: does HIV coinfection impair the response to DAA combination therapy?

Objectives

The European Association for the Study of the Liver (EASL) treatment recommendations for hepatitis C no longer discriminate between HIV/hepatitis C virus (HCV)‐coinfected and HCV‐monoinfected patients. However, recent data from Spain are questioning these recommendations on the basis of the findings of higher relapse rates and lower cure rates in HIV/HCV‐infected subjects. The aim of our study was to compare HCV cure rates in monoinfected and coinfected patients from Germany.

Methods

Data acquired from the Deutsches Hepatitis C‐Registry were analysed. A total of 5657 HCV‐monoinfected subjects and 488 HIV/HCV‐coinfected patients were included in the study. Rates of sustained virological response 12 weeks after the scheduled end of therapy (SVR12) were collected in both subgroups and in cirrhotic and noncirrhotic patients.

Results

HIV/HCV‐coinfected patients were more frequently male (84.6% vs. 56.4%, respectively; P < 0.001) and younger than HCV‐monoinfected subjects (46.5 ± 9 vs. 53.8 ± 12.5 years, respectively; P < 0.001). The CD4 blood cell count was > 350 cells/μL in 63.1% of HIV‐positive subjects and 88.7% were on antiretroviral therapy. SVR12 rates were 90.3% (5111 of 5657) in our HCV‐monoinfected cohort and 91.2% (445 of 488) in our coinfected patients. Liver cirrhosis was confirmed in 1667 of 5657 (29.5%) monoinfected patients and 84 of 488 (17.2%; P < 0.001) coinfected patients. SVR12 rates did not differ between HCV‐monoinfected and HIV/HCV‐coinfected patients with liver cirrhosis (87.8% vs. 89.3%, respectively; P = 0.864). A treatment duration of 8 weeks did not reduce the percentage of patients with SVR12 in either subgroup (93.7% in both groups).

Conclusions

We found high SVR12 rates in monoinfected as well as coinfected individuals. No differences were detected between the two subgroups regardless of whether there was accompanying liver cirrhosis or a shortened treatment duration.

     

Studies of the TSH radioreceptor assay.

We have examined several variables in the reagents and procedures used in the TSH radioreceptor assay, the binding of iodinated TSH to its thyroidal receptor. We found that iodinated bovine TSH (S.A. 30 U/mg) was more effectively bound to receptor than iodinated human TSH (S.A. 7.3 U/mg). Iodination of TSH was the Bolton-Hunter acylation method apparently prevented binding to TSH receptor. Surgically removed human thyroid tissue specifically bound 10.3 +/- 1.0 (mean +/- SEM) of added [125I]TSH, but post-mortem human thyroid bound only 3.9 +/- 0.4% of [125I]TSH (p less than 0.001). Maximal binding of [125I]TSH was found at pH 5.8. Many tissue preparations contained activity, possibly due to proteases, which inactivated TSH, and inclusion of a protease inhibitor, aprotinin, significantly increased specific binding.     

Myeloma cell growth arrest, apoptosis, and interleukin-6 receptor modulation induced by EB1089, a vitamin D3 derivative, alone or in association with dexamethasone

We have previously shown that malignant plasma cells expressed the specific receptor for 1,25-dihydroxyvitamin D3 and that this derivative could significantly inhibit the proliferation of such malignant cells. More recently, new vitamin D3 derivatives have been generated with extraordinarily potent inhibitory effects on leukemic cell growth in vitro. These new data prompted us to (re)investigate the capacity of such new vitamin D3 derivatives to inhibit myeloma cell growth in comparison with that of dexamethasone, a potent antitumoral agent in multiple myeloma. In the current study, we show that EB1089, a new vitamin D3 derivative, (1) induces G1 growth arrest of human myeloma cells, which is only partially reversed by interleukin-6 (IL-6); (2) induces apoptosis in synergy with dexamethasone, IL-6, leukemia- inhibitory factor, and Oncostatin M, with an agonistic anti-gp130 monoclonal antibody being unable to prevent this apoptosis; (3) downregulates both the gp80 (ie, the alpha chain of the IL-6 receptor [IL-6Ralpha]) expression on malignant plasma cells and the production of soluble IL-6Ralpha, and finally (4) inhibits the deleterious upregulation of gp80 expression induced by dexamethasone while limiting the dexamethasone-induced upregulation of gp130 expression. Considering that these in vitro effects of EB1089 have been observed at doses obtainable in vivo (without hypercalcemic effects), our present data strongly suggest that EB1089 could have a true interest in the treatment of multiple myeloma, especially in association with dexamethasone.     

Long term treatment of Graves' hyperthyroidism with sodium ipodate

To investigate the long term usefulness of sodium ipodate (Oragrafin) in the management of Graves' hyperthyroidism, we studied the effects of ipodate (500 mg, orally, daily for 23-31 weeks) on serum T3, T4, rT3, and some clinical parameters in five newly diagnosed Graves' hyperthyroid patients. Mean pretreatment serum T3, T4, and rT3 concentrations were 780 ng/dl, 25.4 micrograms/dl, and 118 ng/dl, respectively. One day after the first dose of ipodate, serum T3 decreased by 62% (P less than 0.01), and it was within the normal range thereafter throughout treatment. The serum T4 concentration decreased by 20% (P = 0.09) at 24 h and by 43% (P less than 0.05) at 14 days. Subsequently, serum T4 was 41-65% lower than before treatment throughout the study; rT3 increased 24 h after the first dose of ipodate (118% above baseline; P = 0.1), remained elevated (97-109%) for 10 weeks, and then gradually decreased to the pretreatment level. A marked gain in body weight [5.1 +/- 1.1 (+/- SEM) kg] occurred in all patients. After discontinuation of ipodate, mean thyroid radioiodine (RAI) uptake values increased serially in four patients and were similar to pretreatment values: pretreatment, 74 +/- 6% (+/- SEM); after 7 days, 66 +/- 8%; after 14 days, 71 +/- 7%; after 28 days, 69 +/- 7%. The fifth patients's RAI uptake was 12-16% (vs. a pretreatment value of 48%) from 7-28 days after the end of a 31-week course of ipodate. He remained euthyroid without further treatment for the subsequent 4 months. We conclude that 1) ipodate (500 mg daily) reduces serum T4 and T3 levels as fast and as much as does the 1-g daily dose studied previously; 2) long term use (for 23-31 weeks) of ipodate for the treatment of Graves' hyperthyroidism is clinically feasible; no adverse effects occurred during or after ipodate treatment; and 3) RAI uptake returns to pretreatment levels as early as 7 days after the discontinuation of ipodate. Hence, use of ipodate does not prevent use of 131I therapy for those patients for whom it is otherwise desirable.