The DNA-recognition mode shared by archaeal feast/famine-regulatory proteins revealed by the DNA-binding specificities of TvFL3, FL10, FL11 and Ss-LrpB

The DNA-binding mode of archaeal feast/famine-regulatory proteins (FFRPs), i.e. paralogs of the Esherichia coli leucine-responsive regulatory protein (Lrp), was studied. Using the method of systematic evolution of ligands by exponential enrichment (SELEX), optimal DNA duplexes for interacting with TvFL3, FL10, FL11 and Ss-LrpB were identified as TACGA[AAT/ATT]TCGTA, GTTCGA[AAT/ATT]TCGAAC, CCGAAA[AAT/ATT]TTTCGG and TTGCAA[AAT/ATT]TTGCAA, respectively, all fitting into the form abcdeWWWedcba. Here W is A or T, and e.g. a and a are bases complementary to each other. Apparent equilibrium binding constants of the FFRPs and various DNA duplexes were determined, thereby confirming the DNA-binding specificities of the FFRPs. It is likely that these FFRPs recognize DNA in essentially the same way, since their DNA-binding specificities were all explained by the same pattern of relationship between amino-acid positions and base positions to form chemical interactions. As predicted from this relationship, when Gly36 of TvFL3 was replaced by Thr, the b base in the optimal DNA duplex changed from A to T, and, when Thr36 of FL10 was replaced by Ser, the b base changed from T to G/A. DNA-binding characteristics of other archaeal FFRPs, Ptr1, Ptr2, Ss-Lrp and LysM, are also consistent with the relationship

Estrogen receptor transcription and transactivation: Estrogen receptor alpha and estrogen receptor beta - regulation by selective estrogen receptor modulators and importance in breast cancer

Estrogens display intriguing tissue-selective action that is of great biomedical importance in the development of optimal therapeutics for the prevention and treatment of breast cancer, for menopausal hormone replacement, and for fertility regulation. Certain compounds that act through the estrogen receptor (ER), now referred to as selective estrogen receptor modulators (SERMs), can demonstrate remarkable differences in activity in the various estrogen target tissues, functioning as agonists in some tissues but as antagonists in others. Recent advances elucidating the tripartite nature of the biochemical and molecular actions of estrogens provide a good basis for understanding these tissue-selective actions. As discussed in this thematic review, the development of optimal SERMs should now be viewed in the context of two estrogen receptor subtypes, ERα and ERβ, that have differing affinities and responsiveness to various SERMs, and differing tissue distribution and effectiveness at various gene regulatory sites. Cellular, biochemical, and structural approaches have also shown that the nature of the ligand affects the conformation assumed by the ER-ligand complex, thereby regulating its state of phosphorylation and the recruitment of different coregulator proteins. Growth factors and protein kinases that control the phosphorylation state of the complex also regulate the bioactivity of the ER. These interactions and changes determine the magnitude of the transcriptional response and the potency of different SERMs. As these critical components are becoming increasingly well defined, they provide a sound basis for the development of novel SERMs with optimal profiles of tissue selectivity as medical therapeutic agents

Development of radiolabeled dextran coated iron oxide nanoparticles with 111In and its biodistribution studies

Background: The main aim of this study is to radiolabel dextran coated iron oxide nanopartcles (NPs) (with 80 nm hydrodynamic size) with the Indium-111 and evaluaton their biodistributon after intravenous injecton normal mice. Materials and Method: The chelator Diethylenetriamine Pentaacetc Acid (DTPA) dianhydride was conjugated to SPION using a small modificaton of the well-known cyclic anhydride method at a rato of 1:5 (NPs:DTPA) molar rato. The reacton was purified with magnetc assortng columns (MACs) using high gradient magnetc field following incubaton. Then the radiochemical purity of the radiolabeled NPs were determined using RTLC method. The magnetc propertes of nanopartcles were measured by a 1.5 tesla clinical human MRI. Results: The NPs showed high super paramagnetc propertes whereas their r2/r1was 17.6. The RTLC showed that the purity of compound was above 99% after purificaton and the compound has shown a good in-vitro stability untl 6 hours in the presence of human serum. The biodistributon of 111In-DTPA-NPs in mice demonstrated high uptake in the retculoendothelial system (RES) and the blood clearance was so fast. Conclusion: Due to magnificent uptakes of this radiotracer in the liver and spleen, its stability and their fast clearance from other tssues, especially in blood, it is suggested that this radiotracer would be suitable for RES theranostcs purposes

Long-term follow-up of seven patients with ophthalmopathy not associated with thyroid autoimmunity: heterogeneity of autoimmune ophthalmopathy

Tom McCorquodale,1 Hooshang Lahooti,1 Bamini Gopinath,2 Jack R Wall11Department of Medicine, Nepean Clinical School, the University of Sydney, Penrith, NSW, Australia; 2Centre for Vision Research, the University of Sydney, Westmead Hospital, Westmead, NSW, AustraliaBackground: Ophthalmopathy is the most common extrathyroidal manifestation of Graves' disease. However, in approximately 5% of cases this autoimmune eye disorder occurs in the apparent absence of Graves' hyperthyroidism: the so-called euthyroid Graves' disease (EGD).Methods: Seven patients with EGD were followed for evidence of thyroid and orbital autoimmunity, for up to 10 years. Calsequestrin and collagen XIII antibodies were measured by enzyme linked immunosorbent assay (ELISA), and TSH-receptor (TSH-r) antibodies were measured as TSH-r-binding antibody (TRAb) and thyroid-stimulating immunoglobulin (TSI). Eye signs were characterized and quantified as clinical activity score (CAS), NOSPECS classes, Nunery types 1 and 2, and margin-reflex distance (MRD).Results: Calsequestrin antibodies were detected on at least one occasion in three of the seven patients and collagen XIII antibodies were detected one or more times in five patients. In one patient with isolated congestive ophthalmopathy who was studied intensely, collagen XIII antibodies were initially positive and then became negative as the eye disease stabilized, while antibodies targeting calsequestrin were always negative. TRAb was not detected in any patient, but TSI was detected in three patients on one occasion each. Ultrasound abnormalities were found in four of the six patients for whom this was carried out, but there was no clear evidence for thyroiditis in any of these patients. For comparison, 13 patients were studied with typical Graves' ophthalmopathy. There were no significant differences compared to EGD in respect to the prevalence of positive calsequestrin or collagen XIII antibodies, but these patients included more smokers (eight out of 13 versus none out of seven).Conclusions: Earlier studies suggesting that patients with EGD eventually develop thyroid dysfunction have not been confirmed here, although follow-up continues, and the possibility that such patients have had thyroid autoimmunity in the past, or that they will develop it in the future cannot be excluded. Overall, it is likely that the ophthalmopathy associated with Graves' hyperthyroidism is the same disease as that observed in patients – such as those reported here – in whom thyroid dysfunction and thyroid autoimmunity are not present during the period of follow-up. The role of autoimmunity against the TSH-r in euthyroid patients with ophthalmopathy has not been proven and the significance of the orbital antibodies is unclear.Keywords: ophthalmopathy, thyroid eye disease, collagen XIII, calsequestrin, euthyroid Graves' diseas

Does autoimmunity against thyroglobulin play a role in the pathogenesis of Graves’ ophthalmopathy: a review

Thayalini Shanmuganathan,1 Christian Girgis,2 Hooshang Lahooti,1 Bernard Champion,1 Jack R Wall1 1Department of Medicine, Nepean Clinical School, Nepean Hospital, The University of Sydney, Sydney, 2Department of Medicine, Westmead Millennium Institute, The University of Sydney, Sydney, NSW, Australia Abstract: While most authors believe that autoimmunity against the TSH receptor expressed in the orbital connective tissue cells is the main reaction that leads to the development of ophthalmopathy in patients with Graves’ hyperthyroidism, an older hypothesis that deserves fresh consideration is based on the notion that thyroglobulin (Tg) in the thyroid gland passes in a retrograde fashion to the orbit where it is recognized by Tg autoantibodies, leading to inflammation. Here, we review new evidence that supports a role of Tg and propose a new hypothesis based on the notion that Tg is targeted in the orbit leading to a complex cascade of reactions that leads to Graves’ ophthalmopathy. Keywords: ophthalmopathy, Graves’ disease, thyroglobulin, thyroid peroxidase, TSH receptor, lymphocytes, autoantibodies&nbsp

Vitamin D deficiency may be a risk factor for ophthalmopathy in patients with Graves' hyperthyroidism but not Hashimoto's thyroiditis

Aims: Apart from its key role in bone metabolism vitamin D plays a role in immune function, cancer prevention and autoimmunity induction. Vitamin D insufficiency (25-50 nmol/L) and deficiency (serum level < 25 nmol/L) are very common in the West Sydney and Blue Mountains areas of Australia. Vitamin D deficiency may also play a role in the development of ophthalmopathy in patients with thyroid autoimmunity. Methods: We have studied a possible relationship between serum vitamin D level and ophthalmopathy in patients with Graves' disease and Hashimoto's thyroiditis. We studied 37 patients with Graves' disease and 69 with Hashimoto's thyroiditis at their first clinical visit, before any vitamin D replacement. Results: Overall, 70% of patients with Graves' disease, 86% of those with Hashimoto's thyroiditis and 88% of patients with Multi nodular goiter control group were vitamin D deficient or insufficient. Sixty-one % of Graves' patients who were vitamin D deficient and 75% of those who were vitamin D insufficient had ophthalmopathy, defined as a NOSPECS class of two or more, compared to only 27% of patients who were vitamin D replete, this difference was significant by odds ratio [5.03 (confidence interval 1.06 – 23.8) P=0.03] and showed a trend to significance by X² test (P = 0.08). Thirty nine % of Graves' patients who were vitamin D deficient and 25% of those who were vitamin D insufficient had no ophthalmopathy, compared to 73% of patients who were vitamin D replete. Eleven % of patients with Hashimoto's thyroiditis who were vitamin D deficient and 22% of those who were vitamin D insufficient had ophthalmopathy, which was generally mild and often manifest as isolated upper eyelid retraction, compared to 20% of patients who were vitamin D replete, which was not significant. There was no close correlation between vitamin D status and either the activity or severity of the ophthalmopathy, for either Graves' disease or Hashimoto's thyroiditis. Conclusions: Vitamin D deficiency is significantly associated with ophthalmopathy in patients with Graves' hyperthyroidism but not Hashimoto's thyroiditis. The finding that a normal serum vitamin D level was associated with a decreased prevalence of ophthalmopathy in patients with Graves' hyperthyroidism, but not Hashimoto's thyroiditis, suggests that the pathogenesis of the eye changes in the two disorders may be different. It appears that Graves' patients with ophthalmopathy have a greater propensity to vitamin D deficiency as compared to Graves' patients without ophthalmopathy. While the significance of the findings needs to be addressed in a prospective study it seems that vitamin D deficiency is another risk factor for ophthalmopathy in patients with Graves' hyperthyroidism.8 page(s

Assessment of human effective absorbed dose of 67 Ga–ECC based on biodistribution rat data

Methods: For biodistribution data, the animals were sacrificed by CO2 asphyxiation at selected times after injection (0.5, 2 and 48 h, n = 3 for each time interval), then the tissue (blood, heart, lung, brain, intestine, feces, skin, stomach, kidneys, liver, muscle and bone) were removed. The absorbed dose was determined by Medical Internal Radiation Dose (MIRD) method after calculating cumulated activities in each organ.Objective: In a diagnostic context, determination of absorbed dose is required before the introduction of a new radiopharmaceutical to the market to obtain marketing authorization from the relevant agencies. In this work, the absorbed dose of [67 Ga]-ethylenecysteamine cysteine [(67 Ga)ECC] to human organs was determined by using distribution data for rats.Results: Our prediction shows that a 185-MBq injection of 67Ga-ECC into the humans might result in an estimated absorbed dose of 0.029 mGy in the whole body. The highest absorbed doses are observed in the spleen and liver with 33.766 and 16.847 mGy, respectively.Conclusion: The results show that this radiopharmaceutical can be a good SPECT tracer since it can be produced easily and also the absorbed dose in each organ is less than permitted absorbed dose