Assessment of children in the autistic spectrum disorder that carry the Thr92Ala-DIO2 polymorphism.

INTRODUCTION: A polymorphism in the type 2 deiodinase (Thr92Ala-DIO2) gene has been associated with behavioral and cognitive dysfunction as well as neurodegeneration and oxidative stress in the central nervous system. OBJECTIVE: To test whether the minor allele (Ala92) frequency (MAF) is increased in children in the autism spectrum disorder (ASD), and whether carriers of the minor allele exhibit more severe symptoms and/or worse adaptive behavior. STUDY DESIGN: ASD children were evaluated at baseline and yearly throughout the study by psychologists using the following tools: autism behavior checklist, Vineland Adaptative Behaviour Scales II, non-verbal intelligence test SON-R 21/2-7, SON-R 6-40, Weschler scale for intelligence, and autism treatment evaluation checklist. SETTINGS: Academic outpatient mental health facility in Sao Paulo, Brazil. PARTICIPANTS: ASD boys and girls younger than 18 years of age. 132 consecutive ASD children, mostly boys (~ 80%); ~ 50% was classified as verbal. Exclusion criteria were coexistence of sensory and/or physical impairment, or any associated genetic syndromes. RESULTS: Median follow-up was for an uninterrupted period of 937 days (139-1375 days), which did not vary significantly among the genotypes. The MAF was 47% in ASD patients vs. 51% in a local reference population with similar ethnic background; the clinical severity and progression were not affected by the minor allele. Carriers of the minor allele exhibited higher adaptive behavior in the domains "daily living skills" and "communication", which correlated positively with the dose of the minor allele. CONCLUSION: The MAF is not different in ASD children, but carriers of the Thr92Ala-DIO2 polymorphism exhibited higher adaptive behavior.

Perfil clínico, etiologia e escalas de avaliação funcional de pacientes com insuficiência cardíaca avançada: alocação para abordagem paliativa e desfechos hospitalares / Clinical profile, etiology and functional assessment scales of patients with advanced heart failure: allocation for palliative approach and hospital outcomes

INTRODUÇÃO: No conceito do Continuo da Doença Cardiovascular, a sequência de eventos seria iniciada por vários fatores de riscos progredindo por vias e processos fisiopatológicos até o desenvolvimento da lesão cardíaca final, no caso a Insuficiência Cardíaca (IC) em fase avançada. Cuidado Paliativo (CP) é uma abordagem interdisciplinar de tratamento que se concentra em melhorar a qualidade de vida dos pacientes nos diferentes estágios da IC.O racional para implementação de CP com planejamento avançado de cuidados por toda a progressão da doença e no luto , em pacientes com IC avançada ,inclui os seguintes: prognóstico limitado , elevada carga de sintomas , rehospitalizações, baixa qualidade de vida, comorbidades e estresse dos cuidadores OBJETIVOS: Caracterizar o perfil clínico dos pacientes cardiopatas incluídos para abordagem paliativa (AP), associado ao tratamento farmacológico da IC. MÉTODOS: Análise de 116 pacientes com IC incluídos para uma AP, entre fevereiro de 2017 a dezembro de 2018. RESULTADOS: Idade média de 74±12,7 anos, com 54% do sexo masculino. Diagnósticos etiológicos da miocardiopatia: incluíram: isquêmica 27%, valvar 25%, arritmogênica 13%, hipertensiva 8,6%, chagásica 8,6% e congênita 2,5%. Diagnósticos mas relevantes no momento da AP foram: insuficiência renal 78%, choque séptico 39,6%, IC 41,4%, choque cardiogênico 30,1%, acidente vascular cerebral 18,1% e pós parada cardiorrespiratória 9,4%, a média de fração de ejeção do VE por ecocardiograma 40%±16,5%. Performances nas atividades cotidianas: 64,6% com dependência total na escala Kartz, 37,9% com necessidade de suporte de vida na escala Karnofsky e 34,5% com alta dependência de cuidados pela Palliative Performance Scala. O intervalo de tempo entre a hospitalização e o óbito vario entre 3 e 405 dias (média de 29 dias). O intervalo de tempo entre a internação e a solicitação e indicação de uma AP variou entre 1 a 177 dias(média de 15 dias). Desfechos clínicos: 12% receberam alta hospitalar, e 7,7% estão em seguimento clínico. CONCLUSÃO: Os pacientes alocados e incluídos no programa de AP encontravam-se em estádios avançado da IC, em fase final de vida, mostrando que a AP foi iniciada tardiamente, caracterizado pelo tempo prolongado de internação , alta dependência de cuidados. DESCRITORES: Cuidados Paliativos, Cardiologia, Cuidados Paliativos na fase final de vida, Insuficiência Cardíaca. (AU)

Carbapenem-resistant Enterobacteriaceae on a cardiac surgery intensive care unit: successful measures for infection control.

BACKGROUND: Carbapenem-resistant Enterobacteriaceae (CRE) cause surgical site infections (SSIs) in intensive care units (ICUs). This study aimed to evaluate the impact of intervention and control measures to reduce CRE colonization and infection rates among patients in the ICU of a cardiac surgery hospital following a CRE outbreak. METHODS: An observational study of the pre- and postintervention status of a cohort of colonized or infected patients in the postoperative adult cardiac surgery ICU was performed between April 2013 and December 2014. As well as the usual measures of screening and cohort nursing, the control measures were enhanced during the intervention period by providing alcohol gel at the bedside, daily bathing with no-rinse 2% chlorhexidine-impregnated wash cloths, and disinfection of surfaces around the patient three times per day. RESULTS: The rates of CRE colonization (P<0.001), primary central-line-associated bloodstream infections (P<0.002) and SSIs (P< 0.003) decreased significantly during the postintervention period. CONCLUSION: The implemented measures were effective in controlling colonization and infection with CRE in the cardiac surgery ICU.

Combined treatment with caffeic and ferulic acid from Baccharis uncinella C. DC. (Asteraceae) protects against metabolic syndrome in mice

Fractionation of the EtOH extract from aerial parts of Baccharis uncinella C. DC. (Asteraceae) led to isolation of caffeic and ferulic acids, which were identified from spectroscopic and spectrometric evidence. These compounds exhibit antioxidant and anti-inflammatory properties and have been shown to be effective in the prevention/treatment of metabolic syndrome. This study investigated whether the combined treatment of caffeic and ferulic acids exhibits a more significant beneficial effect in a mouse model with metabolic syndrome. The combination treatment with caffeic and ferulic acids was tested for 60 days in C57 mice kept on a high-fat (40%) diet. The data obtained indicated that treatment with caffeic and ferulic acids prevented gain in body weight induced by the high-fat diet and improved hyperglycemia, hypercholesterolemia and hypertriglyceridemia. The expression of a number of metabolically relevant genes was affected in the liver of these animals, showing that caffeic and ferulic acid treatment results in increased cholesterol uptake and reduced hepatic triglyceride synthesis in the liver, which is a likely explanation for the prevention of hepatic steatosis. In conclusion, the combined treatment of caffeic and ferulic acids displayed major positive effects towards prevention of multiple aspects of the metabolic syndrome and liver steatosis in an obese mouse model.

Combined treatment with caffeic and ferulic acid from Baccharis uncinella C. DC. (Asteraceae) protects against metabolic syndrome in mice.

Fractionation of the EtOH extract from aerial parts of Baccharis uncinella C. DC. (Asteraceae) led to isolation of caffeic and ferulic acids, which were identified from spectroscopic and spectrometric evidence. These compounds exhibit antioxidant and anti-inflammatory properties and have been shown to be effective in the prevention/treatment of metabolic syndrome. This study investigated whether the combined treatment of caffeic and ferulic acids exhibits a more significant beneficial effect in a mouse model with metabolic syndrome. The combination treatment with caffeic and ferulic acids was tested for 60 days in C57 mice kept on a high-fat (40%) diet. The data obtained indicated that treatment with caffeic and ferulic acids prevented gain in body weight induced by the high-fat diet and improved hyperglycemia, hypercholesterolemia and hypertriglyceridemia. The expression of a number of metabolically relevant genes was affected in the liver of these animals, showing that caffeic and ferulic acid treatment results in increased cholesterol uptake and reduced hepatic triglyceride synthesis in the liver, which is a likely explanation for the prevention of hepatic steatosis. In conclusion, the combined treatment of caffeic and ferulic acids displayed major positive effects towards prevention of multiple aspects of the metabolic syndrome and liver steatosis in an obese mouse model.

Activation and inactivation of thyroid hormone by deiodinases: local action with general consequences.

The thyroid hormone plays a fundamental role in the development, growth, and metabolic homeostasis in all vertebrates by affecting the expression of different sets of genes. A group of thioredoxin fold-containing selenoproteins known as deiodinases control thyroid hormone action by activating or inactivating the precursor molecule thyroxine that is secreted by the thyroid gland. These pathways ensure regulation of the availability of the biologically active molecule T3, which occurs in a time-and tissue-specific fashion. In addition, because cells and plasma are in equilibrium and deiodination affects central thyroid hormone regulation, these local deiodinase-mediated events can also affect systemic thyroid hormone economy, such as in the case of non-thyroidal illness. Heightened interest in the field has been generated following the discovery that the deiodinases can be a component in both the Sonic hedgehog signaling pathway and the TGR-5 signaling cascade, a G-protein-coupled receptor for bile acids. These new mechanisms involved in deiodinase regulation indicate that local thyroid hormone activation and inactivation play a much broader role than previously thought.

The type 2 iodothyronine deiodinase is essential for adaptive thermogenesis in brown adipose tissue.

Type 2 iodothyronine deiodinase (D2) is a selenoenzyme, the product of the recently cloned cAMP-dependent Dio2 gene, which increases 10- to 50-fold during cold stress only in brown adipose tissue (BAT). Here we report that despite a normal plasma 3,5,3'-triiodothyronine (T3) concentration, cold-exposed mice with targeted disruption of the Dio2 gene (Dio2(-/-)) become hypothermic due to impaired BAT thermogenesis and survive by compensatory shivering with consequent acute weight loss. This occurs despite normal basal mitochondrial uncoupling protein 1 (UCP1) concentration. In Dio2(-/-) brown adipocytes, the acute norepinephrine-, CL316,243-, or forskolin-induced increases in lipolysis, UCP1 mRNA, and O(2) consumption are all reduced due to impaired cAMP generation. These hypothyroid-like abnormalities are completely reversed by a single injection of T3 14 hours earlier. Recent studies suggest that UCP1 is primarily dependent on thyroid hormone receptor beta (TR beta) while the normal sympathetic response of brown adipocytes requires TR alpha. Intracellularly generated T3 may be required to saturate the TR alpha, which has an approximately fourfold lower T3-binding affinity than does TR beta. Thus, D2 is an essential component in the thyroid-sympathetic synergism required for thermal homeostasis in small mammals.

Prognostic factors of the results of cardiopulmonary resuscitation in a cardiology hospital.

OBJECTIVE: To analyze the early and late results of cardiopulmonary resuscitation in a cardiology hospital and to try to detect prognostic determinants of both short- and long-term survival. METHODS: A series of 557 patients who suffered cardiorespiratory arrest (CRA) at the Dante Pazzanese Cardiology Institute over a period of 5 years was analyzed to examine factors predicting successful resuscitation and long-term survival. RESULTS: Ressuscitation maneuvers were tried in 536 patients; 281 patients (52.4%) died immediately, and 164 patients (30.6%) survived for than 24 hours. The 87 patients who survived for more than 1 month after CRA were compared with nonsurvivors. Coronary disease, cardiomyopathy, and valvular disease had a better prognosis. Primary arrhythmia occurred in 73.5% of the >1-month survivor group and heart failure occurred in 12.6% of this group. In those patients in whom the initial mechanism of CRA was ventricular fibrillation, 33.3% survived for more than 1 month, but of those with ventricular asystole only 4.3% survived. None of the 10 patients with electromechanical dissociation survived. There was worse prognosis in patients included in the extreme age groups (zero to 10 years and 70 years or more). The best results occurred when the cardiac arrest took place in the catheterization laboratories. The worst results occurred in the intensive care unit and the hemodialysis room. CONCLUSION: The results in our series may serve as a helpful guide to physicians with the difficult task of deciding when not to resuscitate or when to stop resuscitation efforts.

Thyroid hormone stimulation of osteocalcin gene expression in ROS 17/2.8 cells is mediated by transcriptional and post-transcriptional mechanisms.

We investigated the mechanism of thyroid hormone regulation of osteocalcin (OC) gene expression in osteoblast-like cells (ROS 17/2.8). Treatment with tri-iodothyronine (T3) (10(-8) M) increased OC mRNA levels by approximately 3-fold after 24 h and reached a maximum, approximately 5.4-fold, after 48 h. The mRNA levels of other bone-specific genes, alkaline phosphatase and osteopontin, were not affected by T3 treatment. Interestingly, T3 induction of OC mRNA varied according to cell density: approximately 4-fold at approximately 1x10(5) cells/dish and 1.5-fold at 40-60x10(5) cells/dish. The magnitude of OC mRNA induction by T3 was approximately 40% lower than induction by 1,25 dihydroxyvitamin D3 (1,25D3) alone, and the combination of T3+1,25D3 did not further stimulate OC mRNA levels. T3 induction of OC mRNA was not affected by treatment with cycloheximide (10 microg/ml) for 5 h indicating that new protein synthesis is not required for the response. To study the half-life of OC mRNA, ROS 17/2.8 cells were incubated with actinomycin D. The basal half-life of OC mRNA (means+/-s.e.m.) was 6.4+/-0.2 h which was increased significantly with either T3 or 1,25D3 treatment to 10.9+/-0.6 h and 13.5+/-0.4 h respectively. T3 modestly up-regulated the rate of OC gene transcription (1.7+/-0.2-fold) as determined by run-off assay. T3 did not induce a reporter construct containing the rat OC gene (rOC) 5'-flanking region (to -1750 bp) or the previously described rOC vitamin D response element, when transfected into ROS 17/2.8 cells. In conclusion, T3 up-regulates the OC mRNA expression in ROS 17/2.8 cells in a dose-, time- and cell confluence-dependent fashion, and does so by transcriptional and post-transcriptional mechanisms. The greater T3 induction of OC expression in ROS 17/2.8 cells at low cell density is consistent with findings of thyroid hormone action on bone development.

Thyroid hormone--sympathetic interaction and adaptive thermogenesis are thyroid hormone receptor isoform--specific.

In newborns and small mammals, cold-induced adaptive (or nonshivering) thermogenesis is produced primarily in brown adipose tissue (BAT). Heat production is stimulated by the sympathetic nervous system, but it has an absolute requirement for thyroid hormone. We used the thyroid hormone receptor-beta--selective (TR-beta--selective) ligand, GC-1, to determine by a pharmacological approach whether adaptive thermogenesis was TR isoform--specific. Hypothyroid mice were treated for 10 days with varying doses of T3 or GC-1. The level of uncoupling protein 1 (UCP1), the key thermogenic protein in BAT, was restored by either T3 or GC-1 treatment. However, whereas interscapular BAT in T3-treated mice showed a 3.0 degrees C elevation upon infusion of norepinephrine, indicating normal thermogenesis, the temperature did not increase (<0.5 degrees C) in GC-1--treated mice. When exposed to cold (4 degrees C), GC-1--treated mice also failed to maintain core body temperature and had reduced stimulation of BAT UCP1 mRNA, indicating impaired adrenergic responsiveness. Brown adipocytes isolated from hypothyroid mice replaced with T3, but not from those replaced with GC-1, had normal cAMP production in response to adrenergic stimulation in vitro. We conclude that two distinct thyroid-dependent pathways, stimulation of UCP1 and augmentation of adrenergic responsiveness, are mediated by different TR isoforms in the same tissue.

The human type 2 iodothyronine deiodinase is a selenoprotein highly expressed in a mesothelioma cell line.

Types 1 and 3 iodothyronine deiodinases are known to be selenocysteine-containing enzymes. Although a putative human type 2 iodothyronine deiodinase (D2) gene (hDio2) encoding a similar selenoprotein has been identified, basal D2 activity is not selenium (Se)-dependent nor has D2 been labeled with (75)Se. A human mesothelioma cell line (MSTO-211H) has recently been shown to have approximately 40-fold higher levels of hDio2 mRNA than mesothelial cells. Mesothelioma cell lysates activate thyroxine (T(4)) to 3,5,3'-triiodothyronine with typical characteristics of D2 such as low K(m) (T(4)), 1.3 nm, resistance to propylthiouracil, and a short half-life ( approximately 30 min). D2 activity is approximately 30-fold higher in Se-supplemented than in Se-depleted medium. An antiserum prepared against a peptide deduced from the Dio2 mRNA sequence precipitates a (75)Se protein of the predicted 31-kDa size from (75)Se-labeled mesothelioma cells. Bromoadenosine 3'5' cyclic monophosphate increases D2 activity and (75)Se-p31 approximately 2.5-fold whereas substrate (T(4)) reduces both D2 activity and (75)Se-p31 approximately 2-3-fold. MG132 or lactacystin (10 microm), inhibitors of the proteasome pathway by which D2 is degraded, increase both D2 activity and (75)Se-p31 3-4-fold and prevent the loss of D2 activity during cycloheximide or substrate (T(4)) exposure. Immunocytochemical studies with affinity-purified anti-hD2 antibody show a Se-dependent increase in immunofluorescence. Thus, human D2 is encoded by hDio2 and is a member of the selenodeiodinase family accounting for its highly catalytic efficiency in T(4) activation.

Regional physiological adaptation of the central nervous system deiodinases to iodine deficiency.

The goal of the present investigation was to analyze the types 2 (D2) and 3 (D3) iodothyronine deiodinases in various structures within the central nervous system (CNS) in response to iodine deficiency. After 5-6 wk of low-iodine diet (LID) or LID + 2 microg potassium iodide/ml (LID + KI; control), rats' brains were processed for in situ hybridization histochemistry for D2 and D3 mRNA or dissected, frozen in liquid nitrogen, and processed for D2 and D3 activities. LID did not affect weight gain or serum triiodothyronine, but plasma thyroxine (T4) was undetectable. In the LID + KI animals, D3 activities were highest in the cerebral cortex (CO) and hippocampus (HI), followed by the olfactory bulb and was lowest in cerebellum (CE). Iodine deficiency decreased D3 mRNA expression in all CNS regions, and these changes were accompanied by three- to eightfold decreases in D3 activity. In control animals, D2 activity in the medial basal hypothalamus (MBH) was similar to that in pituitary gland. Of the CNS D2-expressing regions analyzed, the two most responsive to iodine deficiency were the CO and HI, in which an approximately 20-fold increase in D2 activity occurred. Other regions, i.e., CE, lateral hypothalamus, MBH, and pituitary gland, showed smaller increases. The distribution of and changes in D2 mRNA were similar to those of D2 activity. Our results indicate that decreases in the expression of D3 and increases in D2 are an integral peripheral component of the physiological response of the CNS to iodine deficiency.

Cloning and functional characterization of an uncoupling protein homolog in hummingbirds.

The cDNA of an uncoupling protein (UCP) homolog has been cloned from the swallow-tailed hummingbird, Eupetomena macroura. The hummingbird uncoupling protein (HmUCP) cDNA was amplified from pectoral muscle (flight muscle) using RT-PCR and primers for conserved domains of various known UCP homologs. The rapid amplification of cDNA ends (RACE) method was used to complete the cloning of the 5' and 3' ends of the open reading frame. The HmUCP coding region contains 915 nucleotides, and the deduced protein sequence consists of 304 amino acids, being approximately 72, 70, and 55% identical to human UCP3, UCP2, and UCP1, respectively. The uncoupling activity of this novel protein was characterized in yeast. In this expression system, the 12CA5-tagged HmUCP fusion protein was detected by Western blot in the enriched mitochondrial fraction. Similarly to rat UCP1, HmUCP decreased the mitochondrial membrane potential as measured in whole yeast by uptake of the fluorescent potential-sensitive dye 3',3-dihexyloxacarbocyanine iodide. The HmUCP mRNA is primarily expressed in skeletal muscle, but high levels can also be detected in heart and liver, as assessed by Northern blot analysis. Lowering the room's temperature to 12-14 degrees C triggered the cycle torpor/rewarming, typical of hummingbirds. Both in the pectoral muscle and heart, HmUCP mRNA levels were 1.5- to 3.4-fold higher during torpor. In conclusion, this is the first report of an UCP homolog in birds. The data indicate that HmUCP has the potential to function as an UCP and could play a thermogenic role during rewarming.

Selective proteolysis of human type 2 deiodinase: a novel ubiquitin-proteasomal mediated mechanism for regulation of hormone activation.

We investigated the mechanism by which T4 regulates its activation to T3 by the type 2 iodothyronine deiodinase (D2). D2 is a short- lived (t1/2 50 min), 31-kDa endoplasmic reticulum (ER) integral membrane selenoenzyme that generates intracellular T3. Inhibition of the ubiquitin (Ub) activating enzyme, E1, or MG132, a proteasome blocker, inhibits both the basal and substrate-induced acceleration of D2 degradation. Using a catalytically active transiently expressed FLAG-tagged-NH2-D2, we found rapid synthesis of high molecular mass (100-300 kDa) Ub-D2 conjugates that are catalytically inactive. Ub-D2 increases when cells are exposed to D2 substrate or MG132 and disappears rapidly after E1 inactivation. Fusion of FLAG epitope to the COOH terminus of D2 prolongs its half-life approximately 2.5-fold and increases the levels of active and, especially, Ub-D2. This indicates that COOH-terminal modification interferes with proteasomal uptake of Ub-D2 that can then be deubiquitinated. Interestingly, the type 1 deiodinase, a related selenoenzyme that also converts T4 to T3 but with a half-life of >12 h, is inactivated but not ubiquitinated or degraded after exposure to substrate. Thus, ubiquitination of the ER-resident enzyme D2 constitutes a specific posttranslational mechanism for T4 regulation of its own activation in the central nervous system and pituitary tissues in which D2-catalyzed T4 to T3 conversion is the major source of intracellular T3.

Distinct subcellular localization of transiently expressed types 1 and 2 iodothyronine deiodinases as determined by immunofluorescence confocal microscopy.

We compared the subcellular localization of FLAG-epitope tagged Types 1 and 2 deiodinases (D1 and D2) transiently expressed in human embryonic kidney (HEK-293) and mouse neuroblastoma (NB2A) cells. D2 is an integral membrane protein based on resistance to extraction at pH 11 with the NH2 terminus in the endoplasmic reticulum (ER). Immunofluorescence confocal microscopy using anti-FLAG and anti-GRP78/BiP antibodies showed the FLAG-D1 signal was found in the periphery of the cells and not co-localized with the ER specific marker GRP78/BiP. On the other hand, FLAG-D2 protein was found in the ER co-localized with the GRP78/BiP protein. These differential distribution patterns indicate subcellular sorting of D1 and D2 is determined by intrinsic protein sequence and can explain the ready access of D2-generated T3 to the nucleus.

Evidence of UCP1-independent regulation of norepinephrine-induced thermogenesis in brown fat.

UNLABELLED: To study the thermal response of interscapular brown fat (IBF) to norepinephrine (NE), urethan-anesthetized rats (1.2 g/kg ip) maintained at 28-30 degrees C received a constant venous infusion of NE (0-2 x 10(4) pmol/min) over a period of 60 min. IBF temperatures (T(IBF)) were recorded with a small thermistor fixed under the IBF pad. Data were plotted against time and expressed as maximal variation (Deltat degrees C). Saline-injected rats showed a decrease in T(IBF) of approximately 0.6 degrees C. NE infusion increased T(IBF) by a maximum of approximately 3.0 degrees C at a dose of 10(4) pmol x min(-1) x 100 g body wt(-1). Surgically thyroidectomized (Tx) rats kept on 0.05% methimazole showed a flat response to NE. Treatment with thyroxine (T(4), 0.8 microg x 100 g(-1) x day(-1)) for 2-15 days normalized mitochondrial UCP1 (Western blotting) and IBF thermal response to NE, whereas iopanoic acid (5 mg x 100 g body wt(-1) x day(-1)) blocked the effects of T(4). Treatment with 3,5, 3'-triiodothyronine (T(3), 0.6 microg x 100 g body wt(-1) x day(-1)) for up to 15 days did not normalize UCP1 levels. However, these animals showed a normal IBF thermal response to NE. Cold exposure for 5 days or feeding a cafeteria diet for 20 days increased UCP1 levels by approximately 3.5-fold. Nevertheless, the IBF thermal response was only greater than that of controls when maximal doses of NE (2 x 10(4) pmol/min and higher) were used. CONCLUSIONS: 1) hypothyroidism is associated with a blunted IBF thermal response to NE; 2) two- to fourfold changes in mitochondrial UCP1 concentration are not necessarily translated into heat production during NE infusion.

Lack of reduction in body fat after treatment with insulin-like growth factor-I in two children with growth hormone gene deletions.

Two patients with growth hormone (GH) gene deletions were treated with recombinant insulin-like growth factor-I (IGF-I) (80-240 (microg/kg/day) and the effects on bone mass and body composition were compared to administration of GH (0.075 U/kg/day) to 8 patients with idiopathic GH deficiency. Bone mass and body composition were measured by dual photon X-ray absorptiometry (DEXA ) before and 3 and 6 months after treatment with GH or IGF-I. Similar increases in growth velocities were observed after GH and IGF-I treatment. Treatment with GH resulted in prompt and significant reduction in body fat percentage (basal, 3 and 6 months: 22+/-10, 17+/-9, and 16+/-9%) whereas body fat percentage remained unchanged after IGF-I therapy (basal, 3 and 6 months: 49, 52 and 48% in patient 1 and 45, 42 and 43% in patient 2, respectively). Fat percentage remained elevated after 18 months of IGF-I treatment in patients 1 (51%) and 2 (44%), respectively. Lean mass and bone mineral content increased with GH and IGF-I therapies. We conclude that reduction of body fat measured by DEXA, observed after administration of GH but not after IGF-I treatment in these children with GH deficiency, suggests that the GH effect on body fat mass is not mediated by circulating IGF-I.

Substrate-induced down-regulation of human type 2 deiodinase (hD2) is mediated through proteasomal degradation and requires interaction with the enzyme's active center.

Type 2 iodothyronine deiodinase (D2) catalyzes the first step in thyroid hormone action, the deiodination of T4 to T3. Endogenous D2 activity is posttranslationally regulated by substrate that accelerates its degradation through the ubiquitin-proteasome pathway. To understand how D2 activity correlates with D2 protein during its normal decay and rT3-induced down-regulation, HEK-293 cells, transiently expressing human D2, were labeled with Na75SeO3 and then treated with 100 microM cycloheximide (CX), 30 nM rT3, and/or 10 microM MG132, a specific proteasome inhibitor, for 2-4 h. D2 protein and enzyme activity changed in parallel, disappearing with a half-life of 2 h in the presence of CX, or 1 h when CX + rT3 were combined. Treatment with MG132 blocked these effects. We created selenocysteine (Sec) 133 to cysteine (Cys) or alanine (Ala) D2 mutants, without changing Sec 266. The CysD2 activity and protein levels were also parallel, with a similar half-life of approximately 2 h, whereas the rT3-induced D2 down-regulation required approximately 1000-fold higher rT3 concentration (30 microM) due to a proportionally higher Michaelis constant of CysD2. In similar experiments, the AlaD2 mutant retained the short half-life but was not catalytically active and not susceptible to rT3-accelerated degradation. We conclude that substrate-induced loss of D2 activity is due to proteasomal degradation of the enzyme and requires interaction with the catalytic center of the protein.

Morphometric dual-energy X-ray absorptiometry of the spine: report of a large series and correlation with axial bone mineral density.

We studied vertebral morphometry and its relation to bone mineral density (BMD) in normal Brazilian women (n = 605). All women (age 22-97 years) were ambulatory and healthy. A lateral spine scan was done for morphometric X-ray absorptiometry using an imaging densitometer. In 429 of these women, BMD of the spine and proximal femur also were measured using dual-energy X-ray absorptiometry. All women were white with mean (+/- 1 SD) age of 53.7 (+/- 9.5) years. About 21% of the women over 50 years had a T score for spine BMD lower than -2.5 SD, and 7% had a femoral neck BMD below this osteoporosis threshold. Vertebral heights (anterior, HA; middle, HM; and posterior, HP) and ratios (HA/HP and HM/HP) were assessed. There was no systematic difference between younger (20-49 years) and older (50+ years) women in heights or ratios. The vertebral heights were normalized for those observed in each individual case for the L2-L4 sequence. This normalization was adequate for all vertebral heights; the Z score averaged about +0.1. The average Z score for HA/HP was +0.01, but that for the HM/HP was -0.72, indicating that the latter ratio might differ from the reference population used (white American and European women). We observed a small positive correlation between vertebral heights and spine or femur BMD, but this was due entirely to the influence of body size on BMD. On a group basis, the HM/HP showed a significant association with axial BMD; the 1 SD difference between the lowest and highest quartile was associated with a difference of 8-15% (0.5-1.0 SD) in axial BMD.

Development of compensatory thermogenesis in response to overfeeding in hypothyroid rats.

Intact or surgically thyroidectomized (Tx) adult male Wistar rats, weighing 150-200 g, were fed a standard chow diet (approximately 1.8 Cal/g) or a high calorie (approximately 3.8 Cal/g) diet (cafeteria diet) for up to 30 days. Daily energy intake was about 5-fold higher in the rats fed the cafeteria diet regardless of their thyroid status. The cafeteria diet caused the retroperitoneal white fat pad to increase by approximately 2-fold, the volume of isolated white adipocytes to increase by 2-fold, and the total body fat to increase by a factor of approximately 3, again regardless of thyroid status. It also increased basal metabolic rate by about 20% in intact rats and by about 50% in Tx rats. The brown fat thermal response to norepinephrine (NE) infusion was approximately 2-fold increased in the intact rats fed the cafeteria diet. However, in the Tx rats, the brown fat thermal response to NE was blunted regardless of the dietary regimen adopted. In both intact and Tx rats, the cafeteria diet increased total brown fat mitochondria, uncoupling protein percentage, and total brown fat uncoupling protein by about 3-, 2-, and 5-fold, respectively. Serum leptin levels also increased approximately 4-fold in intact rats fed the cafeteria diet. However, in Tx rats, leptin levels did not change significantly during overfeeding. In conclusion, hypothyroidism caused the brown fat to become unresponsive to NE, even after 1 month on the cafeteria diet. However, these rats were able to increase basal metabolic rate and, as assessed by several different parameters, did not gain fat beyond that observed in intact controls kept on a similar overfeeding schedule.