Background: Following radioiodine ( 131 I) therapy, both late recognition of hypothyroidism and treatment failure may result in adverse outcomes. Aim: We sought to assess indicators of both incipient hypothyroidism and treatment failure following 131 I and determine factors predictive of weight gain. Subjects and methods: Retrospective study of 288 patients receiving 131 I for treatment of Graves’ thyrotoxicosis. Primary outcome measures were thyroid status and weight change at 1 yr following 131 I. Results: The treatment failure rate at 1 yr was 13.5%. Hypothyroidism developed in 80.9%, with 58.5% of patients having levels of free T4 (fT 4 ) <6 pmol/l at diagnosis. Patients receiving thionamides before and after 131 I had significantly higher levels of treatment failure (23.3%) than those with no thionamide exposure (6.3%, p =0.003), but also had more active Graves’ disease. Following 131 I, development of a detectable TSH or low-normal fT 4 levels was not associated with recurrent thyrotoxicosis. Median weight gain was 5.3 kg, although patients with nadir fT 4 levels <6 pmol/l gained an average 2 kg more than those with levels >6 pmol/l ( p =0.05). The main predictor of weight gain was fT 4 level immediately prior to treatment; those in the lowest tertile gained a median 3.1 kg whilst those in the highest tertile gained 7.4 kg (median difference 4.3 kg; 95% confidence interval: 2.5–6.2). Conclusions: Marked hypothyroidism following 131 I is common and often occurs early. Simple biochemical parameters may help identify incipient hypothyroidism and potentially limit excess weight gain. Treatment failure is common in patients with severe thyrotoxicosis and in such cases larger doses of 131 I may be warranted.

Abstract Context. An elevated troponin I (TnI) is associated with a poorer prognosis during critical illness. Objective. Our aims were to determine whether significant paracetamol-induced hepatotoxicity was associated with an elevated TnI; if this elevation was persistent and was associated with worse clinical outcomes. Materials and methods. In this retrospective cohort study, the requirement for orthotopic liver transplantation (OLT) or death and/or the development of multiorgan failure (MOF) was evaluated for 48 consecutive patients admitted to the Royal Infirmary of Edinburgh (a university tertiary referral centre) with acute liver injury or acute liver failure secondary to paracetamol overdose. Results. TnI was elevated (≥ 0.05 ng/L) in 13/48 patients (27%). This appeared to be sustained for at least 6 days which has not been shown previously in the context of Acute Liver Injury (ALI). Elevated TnI was strongly associated with MOF, with the requirement for inotropic support being the strongest predictor (p = 0.003, OR 9.00, 95% CI 2.13–37.98). TnI elevations also correlated strongly with Acute Physiology and Chronic Health Evaluation (APACHE) II scores (p = 0.0006, r = 0.482, 95% CI 0.22–0.68) and with interleukin 6 (IL-6) levels (p = 0.0001, r = 0.55, 95% CI 0.29–0.73). Although a raised TnI was associated with a markedly increased risk of death or orthotopic liver transplant (p = 0.005, OR 7.73, 95% CI 1.87–32.05) on univariate analysis, this was primarily seen in the context of MOF (SOFA score p = 0.003, OR 1.23, 95% CI 1.07–1.41) and was not an independent predictor of death. There was no correlation between TnI or outcome with other cardiac biomarkers and markers of cardiovascular risk. Discussion and Conclusion. An elevated TnI in the context of acute liver injury or liver failure following paracetamol overdose is associated with a significantly worse patient outcome but it is not an independent prognostic factor. Further studies should be undertaken to investigate the mechanism behind this elevated troponin association.

Introduction Activated macrophages may play a critical role in the pathogenesis of acute liver failure (ALF). Serum ferritin (SF) is a circulating marker of macrophage activation, and heavy (H) isoforms of ferritin may have immunostimulatory effects. However, ferritin may be released from necrotic liver, confounding SF interpretation in ALF. The SF/ALT ratio may have prognostic value in non-paracetamol ALF, but has not been examined in patients with paracetamol (POD)-ALF. Methods Analysis of SF levels in acute liver injury patients admitted to a tertiary liver center, with western blotting and immunohistochemistry for ferritin isoforms. Results Retrospective database analysis revealed elevated admission SF (>300 μg/l) in 109/124 (87.9%) of acute liver injury patients. Extreme SF elevations (>10000 μg/l) were more common in POD (36/71, 50.7%) compared with non-POD patients (5/53, 9.4%, p<0.001). Extremely elevated admission SF was confirmed in a prospective cohort of 47 POD cases (22/47, 46.8%). In both POD cohorts, admission SF was significantly higher in patients who died/were transplanted compared with spontaneous survivors (p=0.001, AUC 0.722 (95% CI 0.614 to 0.831) and in patients who developed hepatic encephalopathy (p=0.038) or the systemic inflammatory response syndrome (SIRS, p=0.008). Hyperferritinaemia correlated with proinflammatory (IL-6, Spearman's r=0.442, p=0.006; IL-8, r=0.502, p=0.001) and antiinflammatory (IL-10; r=0.349, p=0.030) cytokine release following POD, and with organ dysfunction (SOFA; r=0.529, p<0.001), but not with serum ALT (r=0.113, p=0.227). The ferritin/ALT ratio did not improve prognostic accuracy in PODs (AUC 0.706 (95% CI 0.595 to 0.817). Immunohistochemistry confirmed H and light (L) ferritin isoform expression in both normal liver tissue and explanted tissue from ALF patients. Immunoblotting of serum from POD patients with elevated SF revealed significant amounts of circulating H-ferritin, with no circulating H-ferritin observed in healthy controls. Conclusion Extreme elevations of SF are common following POD, and are associated with adverse outcomes. SF is a widely available biomarker that may have prognostic value in patients with POD-ALF and merits further evaluation in larger, prospective studies. The correlation with SIRS, organ failure and cytokinaemia and the observation of circulating H ferritin also suggests that SF may be a mediator of adverse outcome. Competing interests None declared.

Olive oil is the main source of fat in the so-called 'Mediterranean diet', a diet which is associated with a lower rate of heart disease and a reduction in all-cause mortality. This study looked at the effect of Picual and Arbequina olive oils, which are rich and poor in polyphenols respectively, on fat and glucose metabolism in an experimental mouse model. The APOE- /- mouse spontaneously develops atherosclerosis with features similar to humans. The results were surprising in that the olive oils decreased atherosclerosis in the mouse model, but at the same time there was an increase in hepatic fat accumulation.

Recent studies published in Oncogene and Proc. Natl. Acad. Sci. USA ascribe a role for selenium, acting through wild type p53, in protecting skin cells in culture from ultraviolet radiation-induced death. While selenium clearly protects cells against ultraviolet radiation-induced death, data that we present and discuss in this letter shows that wild type p53 is not required for such protection. Moreover the non-physiologically high levels of selenium used in some studies leads us to question the relevance of such effects for selenium-induced photoprotection.

The generation of reactive oxygen species has been implicated in ultraviolet radiation (UVR)-induced skin damage. In mice, increasing dietary selenium intake protects skin from UVR-induced DNA damage and photocarcinogenesis. We sought to determine whether selenium supplementation could protect keratinocytes from apoptosis resulting from exposure to broadband (TL20W/12) UVR. Unirradiated cultures contained 6.5+/-1% apoptotic cells; the maximum percentage of apoptotic cells (34+/-5%) was seen 16 h after UVR of 600 J/m(2). Under these conditions cell death from necrosis was 15+/-2.5% of the total cells. A 24-h preincubation with sodium selenite (10 nm-1 mum) or selenomethionine (50 nm-1 mum) protected cultured human keratinocytes from UVR-induced apoptosis. In primary keratinocytes the greatest reduction in apoptosis was found with 100 nm of either selenium compound (71% reduction in the numbers of total apoptotic cells; P<0.01). Supplementation with 100-200 nm selenite or selenomethionine prevented UVR-induced apoptosis, but did not decrease the levels of UVR-induced p53, as measured by Western blotting. Collectively, this data suggests that selenium prevents UVR-induced cell death by inhibiting p53-independent cell death pathways.

Background Ultraviolet radiation (UVR), a ubiquitous environmental genotoxin for the skin, produces DNA damage. The trace element selenium induces synthesis of the glutathione peroxidase and thioredoxin reductase enzyme families. These selenoenzymes detoxify a range of toxic compounds generated by free radicals.Objectives To assess the effects of pretreatment of primary human keratinocytes with selenium on UVR-induced DNA damage.Methods Cells were irradiated with UVR from FS-20 lamps and were subjected to comet assay.Results Comet tail length due to UVR-induced T4 endonuclease V-sensitive sites (caused by cyclopyrimidine dimers, CPDs) increased to 35 +/- 4.5 mum (mean +/- SD) immediately after irradiation (time 0 h, 100%). After 4 h, 68% of the damage remained and after 24 h, 23% of the damage was still present. Treatment with up to 200 nmol L-1 selenomethionine or 50 nmol L-1 sodium selenite had no effect on CPD formation or rates of repair, or on the number of excision repair sites as measured by cytosine arabino furanoside and hydroxyurea treatment. However, selenite and selenomethionine protected against oxidative damage to DNA as measured by formation of formamidopyrimidine (FaPy) glycosylase-sensitive sites, which are indicative of 8-hydroxy-2-deoxyguanosine photoproduct formation. In this assay, irradiation of keratinocytes increased mean +/- SD glycosylase-specific comet tail length from 5 +/- 1.5 mum to 19 +/- 3.3 mum. Preincubation for 18 h with 50 nmol L-1 selenite abolished the UVR-induced increase in comet length. Preincubation with 200 nmol L-1 selenomethionine was similarly protective.Conclusions Selenite and selenomethionine protect keratinocytes from UVR-induced oxidative damage, but not from formation of UVR-induced excision repair sites.

Clinical EndocrinologyVolume 58, Issue 1 p. 20-21 First-line thyroid function tests − TSH alone is not enough G. J. Beckett, G. J. Beckett University Department of Clinical Biochemistry and, Endocrine Clinic, Royal Infirmary, Edinburgh, ScotlandSearch for more papers by this authorA. D. Toft, Corresponding Author A. D. Toft University Department of Clinical Biochemistry and, Endocrine Clinic, Royal Infirmary, Edinburgh, Scotland Dr A. D. Toft, Endocrine Clinic, Royal Infirmary Edinburgh EH3 9YW, Scotland. Tel.: 0131 5362092/3; Fax: 0131 5362091; E-mail: [email protected]Search for more papers by this author G. J. Beckett, G. J. Beckett University Department of Clinical Biochemistry and, Endocrine Clinic, Royal Infirmary, Edinburgh, ScotlandSearch for more papers by this authorA. D. Toft, Corresponding Author A. D. Toft University Department of Clinical Biochemistry and, Endocrine Clinic, Royal Infirmary, Edinburgh, Scotland Dr A. D. Toft, Endocrine Clinic, Royal Infirmary Edinburgh EH3 9YW, Scotland. Tel.: 0131 5362092/3; Fax: 0131 5362091; E-mail: [email protected]Search for more papers by this author First published: 07 January 2003 https://doi.org/10.1046/j.1365-2265.2003.01690.xCitations: 25Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article.Citing Literature Volume58, Issue1January 2003Pages 20-21 RelatedInformation

Background Selenium is an essential trace nutrient necessary for the normal function of the immune system. Selenium compounds protect mice against ultraviolet (UV) B-induced tumours, probably by preventing oxidative damage to the host skin cells and to the host immune system. One possible mechanism of protection is that selenium can prevent oxidative stress-induced release of cytokines such as interleukin (IL)-10, which could suppress cell-mediated immunity.Objectives To determine whether selenium compounds can inhibit UVB induction of IL-10 protein in murine keratinocytes.Methods The murine keratinocyte cell line PAM 212 was treated with or without selenomethionine (50-200 nmol L-1) or sodium selenite (1-50 nmol L-1) for 24 h before exposure to 200 J m(-2) UVB. The cells were stained with an antibody to IL-10, 24 h after irradiation.Results Preincubation with both selenium compounds inhibited UVB induction of IL-10 immunostaining, although selenomethionine was more effective. Pretreatment with 200 nmol L-1 selenomethionine decreased IL-10 immunostaining to levels seen in the unirradiated controls.Conclusions The protective effects of selenium against UVB-induced skin cancer in murine models may result, in part, from its ability to inhibit release of cytokines that are capable of suppressing cell-mediated immunity.

The human endothelial cell line EAhy926 was used to determine the importance of selenium in preventing oxidative damage induced by tert-butyl hydroperoxide (tert-BuOOH) or oxidised low density lipoprotein (LDLox). In cells grown in a low selenium medium, tert-BuOOH and LDLox killed cells in a dose-dependent manner. At 555 mg/l LDLox or 300 microM tert-BuOOH, >80% of cells were killed after 20 h. No significant cell kill was achieved by these agents if cells were pre-incubated for 48 h with 40 nM sodium selenite, a concentration that maximally induced the activities of cytoplasmic glutathione peroxidase (cyGPX; 5.1-fold), phospholipid hydroperoxide glutathione peroxidase (PHGPX;1.9-fold) and thioredoxin reductase (TR; 3.1-fold). Selenium-deficient cells pre-treated with 1 microM gold thioglucose (GTG) (a concentration that inhibited 25% of TR activity but had no inhibitory effect on cyGPX or PHGPX activity) were significantly (P<0.05) more susceptible to tert-BuOOH toxicity (LC(50) 110 microM) than selenium-deficient cells (LC(50) 175 microM). This was also the case for LDLox. In contrast, cells pre-treated with 40 nM selenite prior to exposure to GTG were significantly more resistant to damage from tert-BuOOH and LDLox than Se-deficient cells. Treatment with GTG or selenite had no significant effect on intracellular total glutathione concentrations. These results suggest that selenium supplementation, acting through induction of TR and GPX, has the potential to protect the human endothelium from oxidative damage.

Selenium (Se) can protect endothelial cells (EC) from oxidative damage by altering the expression of selenoproteins with antioxidant function such as cytoplasmic glutathione peroxidase (cyGPX), phospholipid hydroperoxide glutathione peroxidase (PHGPX) and thioredoxin reductase (TR). If the role of Se on EC function is to be studied, it is essential that a model system be chosen which reflects selenoprotein expression in human EC derived from vessels prone to developing atheroma. We have used [75Se]-selenite labelling and selenoenzyme measurements to compare the selenoproteins expressed by cultures of EC isolated from different human vasculature with EC bovine and porcine aorta. Only small differences were observed in selenoprotein expression and activity in EC originating from human coronary artery, human umbilical vein (HUVEC), human umbilical artery and the human EC line EAhy926. The selenoprotein profile in HUVEC was consistent over eight passages and HUVEC isolated from four cords also showed little variability. In contrast, EC isolated from pig and bovine aorta showed marked differences in selenoprotein expression when compared to human cells. This study firmly establishes the suitability and consistency of using HUVEC (and possibly the human cell line EAhy926) as a model to study the effects of Se on EC function in relation to atheroma development in the coronary artery. Bovine or porcine EC appear to be an inappropriate model.

Cytosolic thioredoxin reductase (TR) is an FAD-containing homodimeric selenoenzyme which, together with thioredoxin (Trx) and NADPH, forms a powerful oxidoreductase system. Cytoplasmic glutathione peroxidase (GPX-1) is a selenoprotein with antioxidant activity. The TR/Trx system has been associated with cellular processes including regulation of cell growth, and modification of activity of transcription factors. TR may also act as an antioxidant. We have measured TR activity, TR concentration, and GPX-1 activity in human hepatic cytosols from foetuses and neonates. The concentration of TR was significantly greater (P<0.05) in foetal (43.6, 37.9-50.8 microg/g protein, median, interquartile range) than in neonatal liver (11.6, 8.70-15.0 microg/g). This was also true of TR activity which was 2.1, 1.8-2.5 U/g protein in foetal, and 0.65, 0.44-0.74 U/g protein in neonatal liver (P<0.0005). Similarly, GPX-1 activity was significantly higher (P<0.005) in the foetal (199.7, 144.0-227.9 U/g protein) than in neonatal (77.0, 58.4-110.3 U/g protein) hepatic cytosol. Overall, foetal liver expressed approx. 3-fold higher activities of TR and GPX-1 than neonatal liver.

The ability of selenium to protect cultured human coronary artery endothelial cells (HCAEC), human umbilical vein endothelial cells (HUVEC) and bovine aortic endothelial cells (BAEC) from oxidative damage induced by 100 microM t-butyl hydroperoxide (t-BuOOH) was compared. Preincubation of human endothelial cells for 24 h with sodium selenite at concentrations as low as 5 nM provided significant protection against the harmful effects of 100 microM t-BuOOH, with complete protection being achieved with 40 nM selenite. The preincubation period was required for selenite to exert this protective effect on endothelial cells. When compared with selenium-deficient cells, the activities of cytoplasmic glutathione peroxidase (GPX-1), phospholipid hydroperoxide glutathione peroxidase (GPX-4) and thioredoxin reductase (TR) were each induced approx. 3--4-fold by 40 nM selenite. HCAEC and HUVEC showed great similarity in their relative abilities to resist oxidative damage in the presence and absence of selenite, and the activities of TR and the GPXs were also similar in these cell types. BAEC were more susceptible to damage by 100 microM t-BuOOH than were human endothelial cells, and could not be protected completely by incubation with selenite at concentrations up to 160 nM. The activity of TR in human endothelial cells was approx. 25-fold greater than that in BAEC of a similar selenium status, but GPX-1 and GPX-4 activities were not significantly different between the human and bovine cells. These studies, although performed with a small number of cultures, show for the first time that selenium at low doses can provide significant protection of the human coronary artery endothelium against damage by oxidative stress. TR may be an important antioxidant selenoprotein in this regard, in addition to the GPXs. The data also suggest that HUVEC, but not BAEC, represent a suitable model system in which to study the effects of selenium on the endothelium of human coronary arteries.

We have investigated thyroid hormone deiodination in the liver, kidney and thyroid of the domestic cat. Affinity labelling with (125)I-bromoacetyl reverse T(3) (125)(I-BrAc-rT(3) demonstrated that liver and kidney, but not the thyroid, express type I iodothyronine deiodinase (IDI), results that were confirmed by measuring the activity of the IDI using (125)I-rT(3) and T(4) as substrate. Feline hepatic and renal IDI metabolised rT(3) at approximately 0.2% of the rate of rat hepatic IDI under identical assay conditions. The K(m) of the feline enzyme was at least 500-fold greater than that of rat IDI. However, feline and rat hepatic IDI metabolised T(4) at a similar rate and had similar K(m) values (1.35 microM and 2.25 microM, respectively). This study demonstrates that cats and rats express IDI in the liver and kidney in similar concentrations; however, the feline enzyme appears unable to utilise rT(3) as a substrate under physiological conditions.

The blood selenium (Se) concentration in the U.K. population has declined by approx. 50% between 1974 and 1991, reflecting a large decrease in dietary Se supply, with intakes only half the reference nutrient intake of 1 microg/kg body weight. Tissue levels of Se are readily influenced by dietary intake. Therefore selenoprotein activity may be sub-optimal due to low Se status, and thus compromise normal cell function. To examine the effects of changing Se intake on selenoproteins, we have determined the relative effectiveness of organic selenomethionine and inorganic sodium selenite (50 microg of Se daily for 28 days) in modulating glutathione peroxidase activities in blood cells from 45 healthy men and women, from a U.K. population. Transient and acute changes in lymphocyte, granulocyte and platelet phospholipid-hydroperoxide glutathione peroxidase (GPx4) activity occurred by day 7 or 14 of sodium selenite treatment and by day 7 in lymphocytes from selenomethionine-treated subjects compared with controls taking a placebo. In contrast, GPx4 activity in granulocytes and platelets in the selenomethionine group increased gradually over the 28 days. Cytosolic glutathione peroxidase (GPx1) activity in these blood cells from both treatment groups increased gradually over the 28 days. For each cellular selenoenzyme activity a significant inter-individual difference (P<0.001) in the extent of the response to Se supplementation was observed, but this was not related to blood Se concentrations either before or after treatments. Significant inverse correlations were evident between baseline enzyme activities and percentage change in activity after 28 days of supplementation [e.g. lymphocyte GPx4, r=-0.695 (P<0.001)], indicating that pre-treatment activity may be sub-optimal as a result of poor Se status. The different and contrasting effects that Se supplementation had on blood selenoenzyme activities may be indicative of a difference in metabolic need for Se regulated at the level of Se-dependent cell function.

There is controversy about the correct dose and form of thyroid hormone therapy for patients with hypothyroidism. Despite restoration of serum thyrotropin (TSH) concentrations to normal, many patients complain of excessive weight gain. We have compared weight at diagnosis of hyperthyroidism with that when euthyroid, evidenced by a stable, normal serum TSH concentration, with or without thyroxine (T4) replacement therapy, in patients treated with an 18-month course of antithyroid drugs (43 patients), surgery (56 patients), or 13I (34 patients) for Graves' disease. In addition, weights were recorded before and after treatment of 25 patients with differentiated thyroid carcinoma by total thyroidectomy, 131I, and long-term T4 suppressive therapy, resulting in undetectable serum TSH concentrations. Mean weight gain in patients with Graves' disease who required T4 replacement therapy following surgery was significantly greater than in those of the same age, sex, and severity of hyperthyroidism rendered euthyroid by surgery (3.9 kg) (p < 0.001) or at the end of a course of antithyroid drugs (4.1 kg) (p < 0.001). Weight gain was similar in those requiring T4 replacement following surgery or 131T therapy (10.4 versus 10.1 kg). In contrast, ablative therapy combined with suppression of TSH secretion by T4 in patients with differentiated thyroid carcinoma did not result in weight gain. The excessive weight gain in patients becoming hypothyroid after destructive therapy for Graves' disease suggests that restoration of serum TSH to the reference range by T4 alone may constitute inadequate hormone replacement.

BACKGROUND Free thyroxine (FT4) assays may exhibit biases that are related to serum T4 binding capacity (sBC). We describe two tests that can be used to assess the presence and magnitude of sBC-dependent biases in FT4 assays. METHODS We used a direct equilibrium dialysis FT4 assay as the reference method and compared the results obtained with those of the FT4 assays under investigation, in patient sera having a wide range of sBC. We then compared the expected and observed FT4 results for sera diluted with an inert buffer. Because serum dilution causes a predictable decrease in sBC, an increasingly negative bias on progressive dilution is indicative of a sBC-dependent bias. RESULTS The automated FT4 assay investigated (Vitros FT4) showed no demonstrable sBC-dependent bias by either test. CONCLUSION These two tests can be used to screen for sBC-dependent biases in FT4 assays.

The magnitude of serum thyroxine (T4) binding capacity (sBC) dependent bias in the AXSYM free thyroxine (FT4) assay was assessed using two recently described tests. One of the tests uses a direct equilibrium dialysis (ED) FT4 assay as the reference method. The results obtained with the AXSYM method were compared with those obtained by the ED FT4 method in patient sera having a wide range of sBC. The other test involves comparison of the FT4 results obtained following dilution of sera by an inert buffer, to theoretically derived FT4 results. As serum dilution causes a predictable decrease in sBC, the demonstration of a negative bias whose magnitude increases in parallel to the dilution, is indicative of an sBC-dependent bias. The AXSYM FT4 assay exhibited a significant sBC-dependent bias. This sBC-dependent bias is likely to have been caused by the presence of significant amounts of T4 binding proteins in the assay reagents.