The evolutionary conserved miR-137/325 tandem mediates obesity-induced hypogonadism and metabolic comorbidities by repressing hypothalamic kisspeptin.

BACKGROUND: Obesity-induced hypogonadism (OIH) is a prevalent, but often neglected condition in men, which aggravates the metabolic complications of overweight. While hypothalamic suppression of Kiss1-encoded kisspeptin has been suggested to contribute to OIH, the molecular mechanisms for such repression in obesity, and the therapeutic implications thereof, remain unknown. METHODS: A combination of bioinformatic, expression and functional analyses was implemented, assessing the role of the evolutionary-conserved miRNAs, miR-137 and miR-325, in mediating obesity-induced suppression of hypothalamic kisspeptin, as putative mechanism of central hypogonadism and metabolic comorbidities. The implications of such miR-137/325-kisspeptin interplay for therapeutic intervention in obesity were also explored using preclinical OIH models. RESULTS: MiR-137/325 repressed human KISS1 3'-UTR in-vitro and inhibited hypothalamic kisspeptin content in male rats, while miR-137/325 expression was up-regulated, and Kiss1/kisspeptin decreased, in the medio-basal hypothalamus of obese rats. Selective over-expression of miR-137 in Kiss1 neurons reduced Kiss1/ kisspeptin and partially replicated reproductive and metabolic alterations of OIH in lean mice. Conversely, interference of the repressive actions of miR-137/325 selectively on Kiss1 3'-UTR in vivo, using target-site blockers (TSB), enhanced kisspeptin content and reversed central hypogonadism in obese rats, together with improvement of glucose intolerance, insulin resistance and cardiovascular and inflammatory markers, despite persistent exposure to obesogenic diet. Reversal of OIH by TSB miR-137/325 was more effective than chronic kisspeptin or testosterone treatments in obese rats. CONCLUSIONS: Our data disclose that the miR-137/325-Kisspeptin repressive interaction is a major player in the pathogenesis of obesity-induced hypogonadism and a putative druggable target for improved management of this condition and its metabolic comorbidities in men suffering obesity. SIGNIFICANCE STATEMENT: Up to half of the men suffering obesity display also central hypogonadism, an often neglected complication of overweight that can aggravate the clinical course of obesity and its complications. The mechanisms for such obesity-induced hypogonadism remain poorly defined. We show here that the evolutionary conserved miR137/miR325 tandem centrally mediates obesity-induced hypogonadism via repression of the reproductive-stimulatory signal, kisspeptin; this may represent an amenable druggable target for improved management of hypogonadism and other metabolic complications of obesity.

Dicer ablation in Kiss1 neurons impairs puberty and fertility preferentially in female mice.

Kiss1 neurons, producing kisspeptins, are essential for puberty and fertility, but their molecular regulatory mechanisms remain unfolded. Here, we report that congenital ablation of the microRNA-synthesizing enzyme, Dicer, in Kiss1 cells, causes late-onset hypogonadotropic hypogonadism in both sexes, but is compatible with pubertal initiation and preserved Kiss1 neuronal populations at the infantile/juvenile period. Yet, failure to complete puberty and attain fertility is observed only in females. Kiss1-specific ablation of Dicer evokes disparate changes of Kiss1-cell numbers and Kiss1/kisspeptin expression between hypothalamic subpopulations during the pubertal-transition, with a predominant decline in arcuate-nucleus Kiss1 levels, linked to enhanced expression of its repressors, Mkrn3, Cbx7 and Eap1. Our data unveil that miRNA-biosynthesis in Kiss1 neurons is essential for pubertal completion and fertility, especially in females, but dispensable for initial reproductive maturation and neuronal survival in both sexes. Our results disclose a predominant miRNA-mediated inhibitory program of repressive signals that is key for precise regulation of Kiss1 expression and, thereby, reproductive function.

Clinical, Cellular, and Molecular Evidence of the Additive Antitumor Effects of Biguanides and Statins in Prostate Cancer.

CONTEXT: Prostate cancer (PCa) is one of the leading causes of cancer-related death among the male population worldwide. Unfortunately, current medical treatments fail to prevent PCa progression in a high percentage of cases; therefore, new therapeutic tools to tackle PCa are urgently needed. Biguanides and statins have emerged as antitumor agents for several endocrine-related cancers. OBJECTIVE: To evaluate: (1) the putative in vivo association between metformin and/or statins treatment and key tumor and clinical parameters and (2) the direct effects of different biguanides (metformin/buformin/phenformin), statins (atorvastatin/simvastatin/lovastatin), and their combination, on key functional endpoints and associated signalling mechanisms. METHODS: An exploratory/observational retrospective cohort of patients with PCa (n = 75) was analyzed. Moreover, normal and tumor prostate cells (normal [RWPE-cells/primary prostate cell cultures]; tumor [LNCaP/22RV1/PC3/DU145 cell lines]) were used to measure proliferation/migration/tumorsphere-formation/signalling pathways. RESULTS: The combination of metformin+statins in vivo was associated to lower Gleason score and longer biochemical recurrence-free survival. Moreover, biguanides and statins exerted strong antitumor actions (ie, inhibition of proliferation/migration/tumorsphere formation) on PCa cells, and that their combination further decreased; in addition, these functional parameters compared with the individual treatments. These actions were mediated through modulation of key oncogenic and metabolic signalling pathways (ie, AR/mTOR/AMPK/AKT/ERK) and molecular mediators (MKI67/cMYC/androgen receptor/cell-cycle inhibitors). CONCLUSIONS: Biguanides and statins significantly reduced tumor aggressiveness in PCa, with this effect being more potent (in vitro and in vivo) when both compounds are combined. Therefore, given the demonstrated clinical safety of biguanides and statins, our results suggest a potential therapeutic role of these compounds, especially their combination, for the treatment of PCa.

Unleashing the Diagnostic, Prognostic and Therapeutic Potential of the Neuronostatin/GPR107 System in Prostate Cancer.

Certain components of the somatostatin-system play relevant roles in Prostate Cancer (PCa), whose most aggressive phenotype (Castration-Resistant-PCa (CRPC)) remains lethal nowadays. However, neuronostatin and the G protein-coupled receptor 107 (GPR107), two novel members of the somatostatin-system, have not been explored yet in PCa. Consequently, we investigated the pathophysiological role of NST/GPR107-system in PCa. GPR107 expression was analyzed in well-characterized PCa patient's cohorts, and functional/mechanistic assays were performed in response to GPR107-silencing and NST-treatment in PCa cells (androgen-dependent (AD: LNCaP) and androgen-independent (AI: 22Rv1/PC-3), which are cell models of hormone-sensitive and CRPC, respectively), and normal prostate cells (RWPE-1 cell-line). GPR107 was overexpressed in PCa and associated with key clinical parameters (e.g., advance stage of PCa, presence of vascular invasion and metastasis). Furthermore, GPR107-silencing inhibited proliferation/migration rates in AI-PCa-cells and altered key genes and oncogenic signaling-pathways involved in PCa aggressiveness (i.e., KI67/CDKN2D/MMP9/PRPF40A, SST5TMD4/AR-v7/In1-ghrelin/EZH2 splicing-variants and AKT-signaling). Interestingly, NST treatment inhibited proliferation/migration only in AI-PCa cells and evoked an identical molecular response than GPR107-silencing. Finally, NST decreased GPR107 expression exclusively in AI-PCa-cells, suggesting that part of the specific antitumor effects of NST could be mediated through a GPR107-downregulation. Altogether, NST/GPR107-system could represent a valuable diagnostic and prognostic tool and a promising novel therapeutic target for PCa and CRPC.

RISK FACTORS FOR HYPOGLYCEMIA IN INPATIENTS WITH TOTAL PARENTERAL NUTRITION AND TYPE 2 DIABETES: A POST HOC ANALYSIS OF THE INSUPAR STUDY.

Objective: Treatment of hyperglycemia with insulin is associated with increased risk of hypoglycemia in type 2 diabetes mellitus (T2DM) patients receiving total parenteral nutrition (TPN). The aim of this study was to determine the predictors of hypoglycemia in hospitalized T2DM patients receiving TPN. Methods: Post hoc analysis of the INSUPAR study, which is a prospective, open-label, multicenter clinical trial of adult inpatients with T2DM in a noncritical setting with indication for TPN. Results: The study included 161 patients; 31 patients (19.3%) had hypoglycemic events, but none of them was severe. In univariate analysis, hypoglycemia was significantly associated with the presence of diabetes with end-organ damage, duration of diabetes, use of insulin prior to admission, glycemic variability (GV), belonging to the glargine insulin group in the INSUPAR trial, mean daily grams of lipids in TPN, mean insulin per 10 grams of carbohydrates, duration of TPN, and increase in urea during TPN. Multiple logistic regression analysis showed that the presence of diabetes with end-organ damage, GV, use of glargine insulin, and TPN duration were risk factors for hypoglycemia. Conclusion: The presence of T2DM with end-organ damage complications, longer TPN duration, belonging to the glargine insulin group, and greater GV are factors associated with the risk of hypoglycemia in diabetic noncritically ill inpatients with parenteral nutrition. Abbreviations: ADA = American Diabetes Association; BMI = body mass index; CV% = coefficient of variation; DM = diabetes mellitus; GI = glargine insulin; GV = glycemic variability; ICU = intensive care unit; RI = regular insulin; T2DM = type 2 diabetes mellitus; TPN = total parenteral nutrition.

Dysregulation of the splicing machinery is directly associated to aggressiveness of prostate cancer.

BACKGROUND: Dysregulation of splicing variants (SVs) expression has recently emerged as a novel cancer hallmark. Although the generation of aberrant SVs (e.g. AR-v7/sst5TMD4/etc.) is associated to prostate-cancer (PCa) aggressiveness and/or castration-resistant PCa (CRPC) development, whether the molecular reason behind such phenomena might be linked to a dysregulation of the cellular machinery responsible for the splicing process [spliceosome-components (SCs) and splicing-factors (SFs)] has not been yet explored. METHODS: Expression levels of 43 key SCs and SFs were measured in two cohorts of PCa-samples: 1) Clinically-localized formalin-fixed paraffin-embedded PCa-samples (n = 84), and 2) highly-aggressive freshly-obtained PCa-samples (n = 42). FINDINGS: A profound dysregulation in the expression of multiple components of the splicing machinery (i.e. 7 SCs/19 SFs) were found in PCa compared to their non-tumor adjacent-regions. Notably, overexpression of SNRNP200, SRSF3 and SRRM1 (mRNA and/or protein) were associated with relevant clinical (e.g. Gleason score, T-Stage, metastasis, biochemical recurrence, etc.) and molecular (e.g. AR-v7 expression) parameters of aggressiveness in PCa-samples. Functional (cell-proliferation/migration) and mechanistic [gene-expression (qPCR) and protein-levels (western-blot)] assays were performed in normal prostate cells (PNT2) and PCa-cells (LNCaP/22Rv1/PC-3/DU145 cell-lines) in response to SNRNP200, SRSF3 and/or SRRM1 silencing (using specific siRNAs) revealed an overall decrease in proliferation/migration-rate in PCa-cells through the modulation of key oncogenic SVs expression levels (e.g. AR-v7/PKM2/XBP1s) and alteration of oncogenic signaling pathways (e.g. p-AKT/p-JNK). INTERPRETATION: These results demonstrate that the spliceosome is drastically altered in PCa wherein SNRNP200, SRSF3 and SRRM1 could represent attractive novel diagnostic/prognostic and therapeutic targets for PCa and CRPC.

Regular insulin added to total parenteral nutrition vs subcutaneous glargine in non-critically ill diabetic inpatients, a multicenter randomized clinical trial: INSUPAR trial.

BACKGROUND: There is no established insulin regimen in T2DM patients receiving parenteral nutrition. AIMS: To compare the effectiveness (metabolic control) and safety of two insulin regimens in patients with diabetes receiving TPN. DESIGN: Prospective, open-label, multicenter, clinical trial on adult inpatients with type 2 diabetes on a non-critical setting with indication for TPN. Patients were randomized on one of these two regimens: 100% of RI on TPN or 50% of Regular insulin added to TPN bag and 50% subcutaneous GI. Data were analyzed according to intention-to-treat principle. RESULTS: 81 patients were on RI and 80 on GI. No differences were observed in neither average total daily dose of insulin, programmed or correction, nor in capillary mean blood glucose during TPN infusion (165.3 ± 35.4 in RI vs 172.5 ± 43.6 mg/dL in GI; p = 0.25). Mean capillary glucose was significantly lower in the GI group within two days after TPN interruption (160.3 ± 45.1 in RI vs 141.7 ± 43.8 mg/dL in GI; p = 0.024). The percentage of capillary glucose above 180 mg/dL was similar in both groups. The rate of capillary glucose ≤70 mg/dL, the number of hypoglycemic episodes per 100 days of TPN, and the percentage of patients with non-severe hypoglycemia were significantly higher on GI group. No severe hypoglycemia was detected. No differences were observed in length of stay, infectious complications, or hospital mortality. CONCLUSION: Effectiveness of both regimens was similar. GI group achieved better metabolic control after TPN interruption but non-severe hypoglycemia rate was higher in the GI group. CLINICAL TRIAL REGISTRY: This trial is registered at clinicaltrials.gov as NCT02706119.

Hypothalamic miR-30 regulates puberty onset via repression of the puberty-suppressing factor, Mkrn3.

Mkrn3, the maternally imprinted gene encoding the makorin RING-finger protein-3, has recently emerged as putative pubertal repressor, as evidenced by central precocity caused by MKRN3 mutations in humans; yet, the molecular underpinnings of this key regulatory action remain largely unexplored. We report herein that the microRNA, miR-30, with three binding sites in a highly conserved region of its 3' UTR, operates as repressor of Mkrn3 to control pubertal onset. Hypothalamic miR-30b expression increased, while Mkrn3 mRNA and protein content decreased, during rat postnatal maturation. Neonatal estrogen exposure, causing pubertal alterations, enhanced hypothalamic Mkrn3 and suppressed miR-30b expression in female rats. Functional in vitro analyses demonstrated a strong repressive action of miR-30b on Mkrn3 3' UTR. Moreover, central infusion during the juvenile period of target site blockers, tailored to prevent miR-30 binding to Mkrn3 3' UTR, reversed the prepubertal down-regulation of hypothalamic Mkrn3 protein and delayed female puberty. Collectively, our data unveil a novel hypothalamic miRNA pathway, involving miR-30, with a prominent role in the control of puberty via Mkrn3 repression. These findings expand our current understanding of the molecular basis of puberty and its disease states.

Clinical Utility of Ghrelin-O-Acyltransferase (GOAT) Enzyme as a Diagnostic Tool and Potential Therapeutic Target in Prostate Cancer.

Recent data suggested that plasma Ghrelin O-Acyl Transferase enzyme (GOAT) levels could represent a new diagnostic biomarker for prostate cancer (PCa). In this study, we aimed to explore the diagnostic and prognostic/aggressiveness capacity of GOAT in urine, as well as to interrogate its putative pathophysiological role in PCa. We analysed urine/plasma levels of GOAT in a cohort of 993 patients. In vitro (i.e., cell-proliferation) and in vivo (tumor-growth in a xenograft-model) approaches were performed in response to the modulation of GOAT expression/activity in PCa cells. Our results demonstrate that plasma and urine GOAT levels were significantly elevated in PCa patients compared to controls. Remarkably, GOAT significantly outperformed PSA in the diagnosis of PCa and significant PCa in patients with PSA levels ranging from 3 to 10 ng/mL (the so-called PSA grey-zone). Additionally, urine GOAT levels were associated to clinical (e.g., Gleason-score, PSA levels) and molecular (e.g., CDK2/CDK6/CDKN2A expression) aggressiveness parameters. Indeed, GOAT overexpression increased, while its silencing/blockade decreased cell-proliferation in PCa cells. Moreover, xenograft tumors derived from GOAT-overexpressing PCa (DU145) cells were significantly higher than those derived from the mock-overexpressing cells. Altogether, our results demonstrate that GOAT could be used as a diagnostic and aggressiveness marker in urine and a therapeutic target in PCa.

Oncogenic Role of Secreted Engrailed Homeobox 2 (EN2) in Prostate Cancer.

Engrailed variant-2 (EN2) has been suggested as a potential diagnostic biomarker; however, its presence and functional role in prostate cancer (PCa) cells is still controversial or unknown. Here, we analyzed 1) the expression/secretion profile of EN2 in five independent samples cohorts from PCa patients and controls (prostate tissues and/or urine) to determine its utility as a PCa biomarker; and 2) the functional role of EN2 in normal (RWPE1) and tumor (LNCaP/22Rv1/PC3) prostate cells to explore its potential value as therapeutic target. EN2 was overexpressed in our two cohorts of PCa tissues compared to control and in tumor cell lines compared with normal-like prostate cells. This profile was corroborated in silico in three independent data sets [The Cancer Genome Atlas(TCGA)/Memorial Sloan Kettering Cancer Center (MSKCC)/Grasso]. Consistently, urine EN2 levels were elevated and enabled discrimination between PCa and control patients. EN2 treatment increased cell proliferation in LNCaP/22Rv1/PC3 cells, migration in RWPE1/PC3 cells, and PSA secretion in LNCaP cells. These effects were associated, at least in the androgen-sensitive LNCaP cells, with increased AKT and androgen-receptor phosphorylation levels and with modulation of key cancer-associated genes. Consistently, EN2 treatment also regulated androgen-receptor activity (full-length and splicing variants) in androgen-sensitive 22Rv1 cells. Altogether, this study demonstrates the potential utility of EN2 as a non-invasive diagnostic biomarker for PCa and provides novel and valuable information to further investigate its putative utility to develop new therapeutic tools in PCa.

Spliceosome component SF3B1 as novel prognostic biomarker and therapeutic target for prostate cancer.

Prostate cancer (PCa) is one of the most common cancers types among men. Development and progression of PCa is associated with aberrant expression of oncogenic splicing-variants (eg, AR-v7), suggesting that dysregulation of the splicing process might represent a potential actionable target for PCa. Expression levels (mRNA and protein) of SF3B1, one of the main components of the splicing machinery, were analyzed in different cohorts of PCa patients (clinically localized [n = 84], highly aggressive PCa [n = 42], and TCGA dataset [n = 497]). Functional and mechanistic assays were performed in response to pladienolide-B in nontumor and tumor-derived prostate cells. Our results revealed that SF3B1 was overexpressed in PCa tissues and its levels were associated with clinically relevant PCa-aggressive features (eg, metastasis/AR-v7 expression). Moreover, inhibition of SF3B1 activity by pladienolide-B reduced functional parameters of aggressiveness (proliferation/migration/tumorspheres-formation/apoptosis) in PCa cell lines, irrespective of AR-v7 expression, and reduced viability of primary PCa cells. Antitumor actions of pladienolide-B involved: (1) inhibition of PI3K/AKT and JNK signaling pathways, (2) modulation of tumor markers and splicing variants (AR-v7/In1-ghrelin), and (3) regulation of key components of mRNA homeostasis-associated machineries (spliceosome/SURF/EJC). Altogether, our results demonstrated that SF3B1 is overexpressed and associated with malignant features in PCa, and its inhibition reduces PCa aggressiveness, suggesting that SF3B1 could represent a novel prognostic biomarker and a therapeutic target in PCa.

Plasma ghrelin O-acyltransferase (GOAT) enzyme levels: A novel non-invasive diagnosis tool for patients with significant prostate cancer.

Early detection of PCa faces severe limitations as PSA displays poor-specificity/sensitivity. As we recently demonstrated that plasma ghrelin O-acyltransferase (GOAT)-enzyme is significantly elevated in PCa-patients compared with healthy-controls, using a limited patients-cohort, we aimed to further explore the potential of GOAT to improve PCa diagnosis using an ample patients-cohort (n = 312) and defining subgroups (i.e. significant PCa/metastatic patients, etc.) that could benefit from this biomarker. Plasma GOAT-levels were evaluated by ELISA in patients with (n = 183) and without (n = 129) PCa. Gleason Score ≥ 7 was considered clinically significant PCa. GOAT-levels were higher in PCa patients vs control patients, and in those with significant PCa vs non-significant PCa. GOAT-levels association with the diagnoses of significant PCa was independent from traditional clinical variables (i.e. PSA/age/DRE). Remarkably, GOAT outperformed PSA in patients with PSA-levels ranging 3-20 ng/mL for the significant PCa diagnosis [GOAT-AUC = 0.612 (0.531-0.693) vs PSA-AUC = 0.494 (0.407-0.580)]. A panel of key variables including GOAT/age/DRE/testosterone also outperformed the same panel but with PSA [AUC = 0.720 (0.710-0.730) vs AUC = 0.705 (0.695-0.716), respectively]. Notably, GOAT-levels could also represent a novel predictive biomarker of aggressiveness, as its levels are positively associated with Gleason Score and the presence of metastasis at the time of diagnoses. Altogether, our data reveal that GOAT-levels can be used as a non-invasive biomarker for significant PCa diagnosis in patients at risk of PCa (with PSA: 3-20 ng/mL).

Fluorescence Enhancement of a Cationic Fluorene-Phenylene Conjugated Polyelectrolyte Induced by Nonionic n-Alkyl Polyoxyethylene Surfactants.

The modulation of conjugated polyelectrolyte fluorescence response by nonionic surfactants is dependent on the structures of the surfactant and polymer, polymer average molecular weight, and polyelectrolyte-surfactant interactions. In this paper, we study the effect of nonionic n-alkyl polyoxyethylene surfactants (CiEj) with different alkyl chain lengths (CiE5 with i = 6, 8, 10, and 12) and number of oxyethylene groups (C12Ej with j = 5, 7, and 9) on the photophysics and ionic conductivity of poly{[9,9-bis(6'-N,N,N-trimethylammonium)-hexyl]-2,7-fluorene-alt-1,4-phenylene}bromide (HTMA-PFP) in dimethyl sulfoxide-water 4% (v/v). Molecular dynamics simulations show that HTMA-PFP chains tend to approach as the simulation evolves. However, the minimum distance between the polymer centers of mass increases upon addition of the surfactant and grows with both the surfactant alkyl chain length and the number of oxyethylene groups, although there are no specific polymer-surfactant interactions. A significant increase in the polymer emission intensity has been observed at surfactant concentrations around their critical micelle concentrations (cmcs), which is attributed to polymer aggregate disruption. However, an increase in the solution conductivity for concentrations above the C12E5 cmc has only been observed for the HTMA-PFP/C12E5 system. The enhancement of fluorescence emission intensity and conductivity upon surfactant addition increases with polymer average molecular weights and seems to be controlled by the polymer-surfactant proximity, which is maximum for C10E5 and C12E5.

Prevalence of diabetes, prediabetes, and stress hyperglycemia: insulin therapy and metabolic control in patients on total parenteral nutrition (prospective multicenter study).

OBJECTIVE: The prevalence of carbohydrate metabolism disorders in patients who receive total parenteral nutrition (TPN) is not well known. These disorders can affect the treatment, metabolic control, and prognosis of affected patients. The aims of this study were to determine the prevalence in noncritically ill patients on TPN of diabetes, prediabetes, and stress hyperglycemia; the factors affecting hyperglycemia during TPN; and the insulin therapy provided and the metabolic control achieved. METHODS: We undertook a prospective multicenter study involving 19 Spanish hospitals. Noncritically ill patients who were prescribed TPN were included, and data were collected on demographic, clinical, and laboratory variables (glycated hemoglobin, C-reactive protein [CRP], capillary blood glucose) as well as insulin treatment. RESULTS: The study included 605 patients. Before initiation of TPN, the prevalence of known diabetes was 17.4%, unknown diabetes 4.3%, stress hyperglycemia 7.1%, and prediabetes 27.8%. During TPN therapy, 50.9% of patients had at least one capillary blood glucose of >180 mg/dL. Predisposing factors were age, levels of CRP and glycated hemoglobin, the presence of diabetes, infectious complications, the number of grams of carbohydrates infused, and the administration of glucose-elevating drugs. Most (71.6%) patients were treated with insulin. The mean capillary blood glucose levels during TPN were: known diabetes (178.6 ± 46.5 mg/dL), unknown diabetes (173.9 ± 51.9), prediabetes (136.0 ± 25.4), stress hyperglycemia (146.0 ± 29.3), and normal (123.2 ± 19.9) (P<.001). CONCLUSION: The prevalence of carbohydrate metabolism disorders is very high in noncritically ill patients on TPN. These disorders affect insulin treatment and the degree of metabolic control achieved.

Evolution of urinary iodine excretion over eleven years in an adult population.

BACKGROUND & AIMS: Few prospective cohort studies have evaluated dietary iodine intake and urinary iodine concentrations in the general adult population. We assess the evolution of urinary iodine excretion and factors that may influence it in an adult population followed for 11 years. METHODS: A population-based cohort study was undertaken in Pizarra (Spain). In the three study phases (baseline (n = 886), and 6 (n = 788) and 11 years later (n = 501)), participants underwent an interview and a standardized clinical examination that included a food questionnaire, and thyroid hormone and urinary iodine determinations. Subjects with thyroid dysfunction, palpable goiter or urinary iodine excretion >400 µg/L were excluded. RESULTS: Urinary iodine increased over the years (100.6 ± 70.0 µg/L at baseline vs. 125.4 ± 95.2 µg/L at 6 years and 141.6 ± 81.4 µg/L at 11 years; p < 0.0001). Urinary iodine was significantly higher in subjects who reported iodized salt consumption and in subjects with a higher intake of dairy products (p < 0.05). Consumption of iodized salt (Risk ratio (RR) = 1.23, 95% CI [1.01-2.05]) and dairy products (RR = 2.07, 95% CI [1.01-4.23]), and a baseline urinary iodine concentration ≥100 µg/L (RR = 1.26, 95% CI [1.04-1.53]) were significantly associated with urinary iodine concentrations ≥100 µg/L at 11 years. There is no correlation between thyroid function (TSH, free triiodothyronine or free thyroxine levels) and urinary iodine concentrations in conditions of iodine sufficiency. CONCLUSIONS: The increase in urinary iodine concentrations over eleven years is associated with an increase in iodized salt intake and with the dairy products intake, and possibly with a higher iodine content of dairy products. However, individual variability in urinary iodine excretion was not fully explained by dietary iodine intake alone; previous urinary iodine concentrations were also important.

Effect of the phospholipid chain length and head group on beta-phase formation of poly(9,9-dioctylfluorene) enclosed in liposomes.

We have studied the effect of head group and alkyl chain length on ß-phase formation in poly(9,9-dioctylfluorene) (PFO) solubilized in phospholipid liposomes. Systems studied have three different alkyl chain lengths (1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine [DMPC], 1,2-didodecanoyl-sn-glycero-3-phosphatidylcholine [DLPC], 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine [DPPC]) and head groups (1,2-dimyristoyl-sn-glycero-3-phosphate monosodium salt [DMPA], 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine [DMPE] and 1,2-dimyristoyl-sn-glycero-3-phospho-l-serine sodium salt [DMPS]). Changes in liposome size upon addition of PFO are followed by dynamic light scattering. All the phospholipids induce the formation of PFO ß-phase, which is followed by the emission intensity and deconvolution of the absorption spectra. Both the head group and alkyl chain length affect the yield of ß-phase. The photophysics of PFO incorporated in liposomes is characterized by stationary and time-resolved fluorescence, whereas the polymer-phospholipid interactions have been studied by the effect of the PFO concentration on the phospholipid phase transitions (differential scanning calorimetry [DSC]).

Effect of metal ion hydration on the interaction between sodium carboxylates and aluminum(III) or chromium(III) ions in aqueous solution.

The interaction between sodium octanoate, decanoate, and dodecanoate and aluminum(III) and chromium(III) has been studied in water at natural pH values, starting well below the surfactant critical micelle concentration, using electrical conductivity, turbidity, and potentiometric measurements. With decanoate or dodecanoate, maximum interaction occurs at 3:1 stoichiometry, corresponding to charge neutralization. Although the solutions become turbid with both metal ions, indicating phase separation, differences are observed and attributed to the fact that aluminum(III) is relatively labile to substitution and rapidly replaces its water ligands, whereas chromium(III) is substitution inert. This shows up in well-defined floc formation with Al(3+), whereas Cr(3+) suspensions do not precipitate, probably because that replacement of coordinated water by carboxylate ligands is impeded. This can be overcome by increasing temperature, and differences in the thermal behavior with Al(3+) and Cr(3+) are suggested to be due to increased involvement of substitution reactions in the latter case. The effect of octanoate on the trivalent metal ions is less clear, and with Cr(3+) interaction only occurs when the carboxylate is in excess. Hydrophobic interactions between alkyl chains play a major role in driving phase separation. At high surfactant concentrations, the solid phases do not dissolve, in contrast to what is observed with the corresponding alkylsulfates. This has implications for use of these systems in metal separation through froth flotation. The concentration of metal ions in supernatant solution has been determined for sodium dodecanoate and sodium dodecylsulfate with Al(3+) and Cr(3+) over the whole surfactant concentration range by inductively coupled plasma-mass spectrometry (ICP-MS). From this, association constants have been determined and are found to be larger for the carboxylate than the alkylsulfate, in agreement with the greater Lewis basicity of the -CO(2)(-) group.

Thyroid hormone levels predict the change in body weight: a prospective study.

BACKGROUND: Different studies, mostly cross-sectional, have found an association between low levels of thyroid hormones, even within the normal range, and a greater body mass index. The aim of this study was to determine the association between thyroid function and the risk for obesity. MATERIALS AND METHODS: In this population-based prospective study, measurements were made of anthropometric parameters, thyroid hormone function and urinary iodine in a cohort of the Pizarra Study (n = 937), and repeated 6 years later (n = 784). At the second point, measurements were also made of leptin and adiponectin. RESULTS: Among the persons who were not obese at the start of the study, the odds ratio (OR) of becoming obese for those in the fourth quartile (Q(4)) for free triiodothyronine (FT3) (versus those in Q(1)) was 2·94 (1·46-5·90) (P = 0·005). The OR of becoming obese in persons in Q(4) of FT4 (versus those in Q(1)) was 3·06 (1·23-7·43) (P = 0·01). Those persons in Q(4) of weight gain had a higher FT3 at the 6-year follow-up than those whose weight gain was in Q(1) (P < 0·001). Leptin correlated with thyrotropin (ß = 0·58, P = 0·001) and the FT4 (ß = -1·12, P = 0·005). Adiponectin correlated with FT3 (r = -0·24, P < 0·001). The urinary iodine correlated negatively with both the BMI (ß = -0·08, P = 0·01) and the increase in weight (ß = -0·08, P = 0·04). CONCLUSIONS: The changes in the thyroid hormones could be the consequence, rather than the cause, of the increase in weight. The same pathophysiological mechanisms that induce obesity might also be modifying the thyroid hormone pattern.

On the flocculation and re-dissolution of trivalent lanthanide metal ions by sodium dodecyl sulfate in aqueous solutions.

The interaction between aqueous solutions of trivalent lanthanide ions (M(3+): La(III) and Gd(III) and Tb (III)) at fixed (1mM) concentrations and various concentrations of sodium dodecyl sulfate (SDS), ranging from pre- to post-micellar, has been investigated by ICP-AES (La(III) and Gd(III)), luminescence spectra (Gd(III)) and lifetimes (Tb(III)) and (139)La NMR spectroscopy. It has been found that at concentration ratios, r=[SDS]/[M(3+)], around the charge neutralization value (ca. 3), dodecyl sulfate (DS(-)) anion interacts with the metal ions to form insoluble aggregates. The metal ion-DS(-) complexes remain flocculated for r values below 5-6 (Gd(III) and La(III), respectively), while at higher r values, re-dissolution takes place. The flocculated aggregates have been characterized by X-ray powder diffraction, and show a lamellar structure. Job plot method indicates that a complex with a 1:3 (M(3+):DS(-)) stoichiometry is formed. From ICP-AES analysis, a model based on a three-step mechanism has been developed and association constants calculated. For all systems the interaction between DS(-) and metal ions follows an associative process with K values ranging between K(1)=10 and K(3)=10(4). These data are discussed on the basis of the physical-chemical characteristics of the metal ions. Re-dissolution with increasing surfactant concentration is attributed to formation of mixed lanthanide/sodium dodecyl sulfate aggregates, with the relative lanthanide fraction in these species decreasing with increasing SDS concentration.

How to change the aggregation in the DNA/surfactant/cationic conjugated polyelectrolyte system through the order of component addition: anionic versus neutral surfactants.

The competitive interaction has been studied between double-stranded DNA (dsDNA), the cationic conjugated polyelectrolyte (CPE) poly[9,9-bis(6-N,N,N-trimethylamonium)hexyl)-fluorene-phenylene)] bromide (HTMA-PFP) and anionic or neutral surfactants (sodium dodecyl sulfonate, SDSu, and n-dodecyl pentaoxyethylene glycol ether, C(12)E(5)) in 4% (v/v) dimethyl sulfoxide (DMSO)-water using UV/visible absorption and fluorescence spectroscopy. Dramatic changes are observed in the spectroscopic behavior of the system depending on the order of addition of the reagents, the surfactant charge, and concentration range. If the neutral C(12)E(5) is added to the HTMA-PFP/dsDNA complex, no significant spectroscopic changes are observed. However, if SDSu is added to the same complex, a dramatic increase of the absorbance and emission intensity is observed for surfactant concentrations above the critical micelle concentration (cmc). In contrast, if dsDNA is added to HTMA-PFP/surfactant systems (with surfactant concentrations above their cmc) no significant changes are observed with SDSu, while a dramatic quenching of polymer emission is observed with C(12)E(5), which can be explained quantitatively in terms of HTMA-PFP/surfactant/DNA complexation and the subsequent polymer aggregation upon charge neutralization. The results are compared with those for the binary systems (HTMA-PFP/DNA and HTMA-PFP/surfactants) and indicate the importance of electrostatic interactions between HTMA-PFP and oppositely charged species in the aggregation processes.