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1.
J Endocrinol Invest ; 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38878126

RESUMO

PURPOSE: The use of thyroid hormones (TH) to treat obesity is unsupported by evidence as reflected in international guidelines. We explored views about this practice, and associations with respondent characteristics among European thyroid specialists. METHODS: Specialists from 28 countries were invited to a survey via professional organisations. The relevant question was whether "Thyroid hormones may be indicated in biochemically euthyroid patients with obesity resistant to lifestyle interventions". RESULTS: Of 17,232 invitations 5695 responses were received (33% valid response rate; 65% women; 90% endocrinologists). Of these, 290 (5.1%) stated that TH may be indicated as treatment for obesity in euthyroid patients. This view was commoner among non-endocrinologists (8.7% vs. 4.7%, p < 0.01), private practice (6.5% vs. 4.5%, p < 0.01), and varied geographically (Eastern Europe, 7.3%; Southern Europe, 4.8%; Western Europe, 2.7%; and Northern Europe, 2.5%). Respondents from Northern and Western Europe were less likely to use TH than those from Eastern Europe (p < 0.01). Gross national income (GNI) correlated inversely with this view (OR 0.97, CI: 0.96-0.97; p < 0.001). Having national guidelines on hypothyroidism correlated negatively with treating obesity with TH (OR 0.71, CI: 0.55-0.91). CONCLUSIONS: Despite the lack of evidence, and contrary to guidelines' recommendations, about 5% of respondents stated that TH may be indicated as a treatment for obesity in euthyroid patients resistant to life-style interventions. This opinion was associated with (i) respondent characteristics: being non-endocrinologist, working in private practice, treating a small number of hypothyroid patients annually and (ii) national characteristics: prevalence of obesity, Eastern Europe, low GNI and lack of national hypothyroidism guidelines.

2.
Strahlenther Onkol ; 193(9): 750-755, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28726055

RESUMO

PURPOSE: Gold-marker-based image-guided radiation therapy (IGRT) of the prostate allows to correct for inter- and intrafraction motion and therefore to safely reduce margins for the prostate planning target volume (PTV). However, pelvic PTVs, when coadministered in a single plan (registered to gold markers [GM]), require reassessment of the margin concept since prostate movement is independent from the pelvic bony anatomy to which the lymphatics are usually referenced to. METHODS: We have therefore revisited prostate translational movement relative to the bony anatomy to obtain adequate margins for the pelvic PTVs compensating mismatch resulting from referencing pelvic target volumes to GMs in the prostate. Prostate movement was analyzed in a set of 28 patients (25 fractions each, totaling in 684 fractions) and the required margins calculated for the pelvic PTVs according to Van Herk's margin formula [Formula: see text]. RESULTS: The overall mean prostate movement relative to bony anatomy was 0.9 ± 3.1, 0.6 ± 3.4, and 0.0 ± 0.7 mm in anterior/posterior (A/P), inferior/superior (I/S) and left/right (L/R) direction, respectively. Calculated margins to compensate for the resulting mismatch to bony anatomy were 9/9/2 mm in A/P, I/S, and L/R direction and 10/11/6 mm if an additional residual error of 2 mm was assumed. CONCLUSION: GM-based IGRT for pelvic PTVs is feasible if margins are adapted accordingly. Margins could be reduced further if systematic errors which are introduced during the planning CT were eliminated.


Assuntos
Marcadores Fiduciais , Irradiação Linfática , Margens de Excisão , Neoplasias da Próstata/radioterapia , Erros de Configuração em Radioterapia/prevenção & controle , Radioterapia Guiada por Imagem/métodos , Radioterapia de Intensidade Modulada , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/patologia , Planejamento da Radioterapia Assistida por Computador , Medição de Risco
3.
Appl Environ Microbiol ; 79(2): 655-62, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23160118

RESUMO

Staphylococcus aureus causes a wide range of infectious diseases in humans and various animal species. Although presumptive host-specific factors have been reported, certain genetic lineages seem to lack specific host tropism, infecting a broad range of hosts. Such Extended-Host-Spectrum Genotypes (EHSGs) have been described in canine infections, caused by common regional human methicillin-resistant S. aureus (MRSA) lineages. However, information is scarce about the occurrence of methicillin-susceptible S. aureus (MSSA) EHSGs. To gain deeper insight into EHSG MSSA and EHSG MRSA of human and canine origin, a comparative molecular study was carried out, including a convenience sample of 120 current S. aureus (70 MRSA and 50 MSSA) isolates obtained from infected dogs. spa typing revealed 48 different spa types belonging to 16 different multilocus sequence typing clonal complexes (MLST-CCs). Based on these results, we further compared a subset of canine (n = 48) and human (n = 14) strains, including isolates of clonal complexes CC5, CC22, CC8, CC398, CC15, CC45, and CC30 by macrorestriction (pulsed-field gel electrophoresis [PFGE]) and DNA-microarray analysis. None of the methods employed was able to differentiate between clusters of human and canine strains independently of their methicillin resistance. In contrast, DNA-microarray analysis revealed 79% of the 48 canine isolates as carriers of the bacteriophage-encoded human-specific immune evasion cluster (IEC). In conclusion, the high degree of similarity between human and canine S. aureus strains regardless of whether they are MRSA or MSSA envisions the existence of common genetic traits that enable these strains as EHSGs, challenging the concept of resistance-driven spillover of MRSA.


Assuntos
Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/classificação , Staphylococcus aureus/isolamento & purificação , Animais , Bacteriófagos/genética , Análise por Conglomerados , Cães , Eletroforese em Gel de Campo Pulsado , Genótipo , Especificidade de Hospedeiro , Humanos , Resistência a Meticilina , Análise em Microsséries , Tipagem de Sequências Multilocus , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/genética , Staphylococcus aureus/fisiologia
5.
Nature ; 438(7066): 355-9, 2005 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-16292310

RESUMO

Population-level analyses often use average quantities to describe heterogeneous systems, particularly when variation does not arise from identifiable groups. A prominent example, central to our current understanding of epidemic spread, is the basic reproductive number, R(0), which is defined as the mean number of infections caused by an infected individual in a susceptible population. Population estimates of R(0) can obscure considerable individual variation in infectiousness, as highlighted during the global emergence of severe acute respiratory syndrome (SARS) by numerous 'superspreading events' in which certain individuals infected unusually large numbers of secondary cases. For diseases transmitted by non-sexual direct contacts, such as SARS or smallpox, individual variation is difficult to measure empirically, and thus its importance for outbreak dynamics has been unclear. Here we present an integrated theoretical and statistical analysis of the influence of individual variation in infectiousness on disease emergence. Using contact tracing data from eight directly transmitted diseases, we show that the distribution of individual infectiousness around R(0) is often highly skewed. Model predictions accounting for this variation differ sharply from average-based approaches, with disease extinction more likely and outbreaks rarer but more explosive. Using these models, we explore implications for outbreak control, showing that individual-specific control measures outperform population-wide measures. Moreover, the dramatic improvements achieved through targeted control policies emphasize the need to identify predictive correlates of higher infectiousness. Our findings indicate that superspreading is a normal feature of disease spread, and to frame ongoing discussion we propose a rigorous definition for superspreading events and a method to predict their frequency.


Assuntos
Transmissão de Doença Infecciosa/estatística & dados numéricos , Síndrome Respiratória Aguda Grave/epidemiologia , Síndrome Respiratória Aguda Grave/transmissão , Busca de Comunicante , Surtos de Doenças/estatística & dados numéricos , Suscetibilidade a Doenças , Humanos , Modelos Biológicos , Síndrome Respiratória Aguda Grave/virologia , Singapura/epidemiologia
6.
Int J Surg Case Rep ; 72: 133-136, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32535527

RESUMO

INTRODUCTION: Total thyroidectomy can be challenging in high-risk patients. Local cervical anesthesia with sedation is an alternative to general anesthesia. CASE PRESENTATION: A 33-year old male patient with cyanotic congenital heart disease due to unrepaired tricuspid atresia type Ic and associated pulmonary arterial hypertension presented with tachycardic atrial fibrillation and amiodarone-induced thyrotoxicosis resulting in recurrent hemodynamic instability. Because of difficulties controlling the thyrotoxic state, the indication for total thyroidectomy was established. Total thyroidectomy was subsequently performed using local anesthesia combined using a hypnosis-analgesia technique instead of intravenous sedation. The intervention and the post-operative course were uneventful. DISCUSSION: A well-established therapist-patient relationship is crucial for a successful induction of hypnosis. Patient motivation and expectations are equally important for a successful implementation of this approach. CONCLUSION: We conclude that hypnosis combined with local anesthesia provides an effective alternative in selected patients with very high anesthesiological risk.

7.
J Clin Invest ; 100(6): 1634-9, 1997 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-9294132

RESUMO

Activating somatic mutations in the thyrotropin (TSH) receptor have been identified as a cause of hyperfunctioning thyroid adenomas, and germline mutations have been found in familial nonautoimmune hyperthyroidism and sporadic congenital hyperthyroidism. All mutations reported to date have been located in the transmembrane domain. We now report an example of an activating mutation in the extracellular, TSH-binding domain, found in a male infant with congenital hyperthyroidism due to a toxic adenoma. The pregnancy was remarkable for fetal tachycardia. Scintigraphic studies demonstrated a large nodule in the right lobe, and a hemithyroidectomy was performed at the age of 2 yr. Direct sequencing of the TSH receptor gene revealed a mutation in one allele resulting in a substitution of serine281 by isoleucine (Ser281--> Ile) in the extracellular domain. The mutation was restricted to the adenomatous tissue. Expression of the Ser281--> Ile mutation in vitro revealed an increase in basal cAMP levels. Affinity for TSH was increased by the mutation. These findings demonstrate that activating mutations can also occur in the extracellular domain of the TSH receptor, and support a model in which the extracellular domain serves to restrain receptor function in the absence of TSH or antibody-induced conformational changes.


Assuntos
Adenoma/genética , Hipertireoidismo/genética , Isoleucina/genética , Receptores da Tireotropina/genética , Serina/genética , Neoplasias da Glândula Tireoide/genética , Adenoma/diagnóstico por imagem , Adenoma/parasitologia , Células Cultivadas , AMP Cíclico/metabolismo , Humanos , Recém-Nascido , Masculino , Mutação , Cintilografia , Compostos de Tecnécio , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Neoplasias da Glândula Tireoide/patologia , Tireotropina/farmacologia , Transfecção , Ultrassonografia
8.
Thyroid ; 15(7): 734-41, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16053392

RESUMO

OBJECTIVE: The autosomal recessive Pendred's syndrome is defined by congenital sensorineural deafness, goiter, and impaired iodide organification. It is caused by mutations in the Pendred's syndrome (PDS) gene that encodes pendrin, a chloride/iodide transporter expressed in the thyroid, the inner ear, and the kidney. In this study we performed clinical and molecular analyses in three siblings from a nonconsanguineous Sicilian family who presented with the clinical features of Pendred's syndrome. PATIENTS AND MOLECULAR ANALYSES: In two sisters and one brother, the clinical diagnosis of Pendred's syndrome was established based on the findings of sensorineural hearing loss and large goiters. Thyroid function tests, perchlorate discharge tests, thyroid ultrasound, and scintigraphy were performed in all affected individuals. Exons 2 to 21 of the PDS gene were amplified by polymerase chain reaction (PCR) and both strands were submitted to direct sequence analysis. RESULTS: The clinical diagnosis of Pendred's syndrome was supported by a positive perchlorate discharge test in the three afflicted siblings. Direct sequence analysis of the PDS gene revealed that all three harbored one allele with a novel mutation 890delC leading to a frameshift mutation and premature stop codon at position 302 (FS297 > 302X). On the other allele, two of the siblings had a previously described transition 1226G > A, which results in the substitution of arginine by histidine at position 409 (R409H). In the index patient, no mutation could be identified on the other allele. In functional studies, these mutants lose the ability of pendrin to mediate iodide efflux. CONCLUSIONS: All three patients included in this study presented with the classic Pendred syndrome triad. Two siblings were compound heterozygous for mutations in the coding region of the PDS gene. The third individual could have an unidentified mutation in a regulatory or intronic region of the PDS gene, or an identical phenotype caused by distinct pathogenic mechanisms.


Assuntos
Bócio/genética , Perda Auditiva Neurossensorial/genética , Proteínas de Membrana Transportadoras/genética , Adolescente , Sequência de Bases , Análise Mutacional de DNA , Saúde da Família , Feminino , Bócio/patologia , Humanos , Linhagem , Sicília , Transportadores de Sulfato
9.
Mol Endocrinol ; 14(9): 1448-61, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10976922

RESUMO

cAMP mediates the effects of TSH by regulating thyroid follicular cell proliferation, differentiation, and function. To assess the functional importance of the cAMP response element binding protein (CREB) in thyroid follicular cell regulation in vivo, we targeted the expression of a dominant negative (DN) CREB isoform to the thyroid glands of transgenic mice using a tissue-specific promoter. Transgenic mice exhibited severe growth retardation and primary hypothyroidism. Serum levels of TSH were elevated 8-fold above normal levels, and T4 and T3 levels were low. Histologically, the mutant thyroid glands were characterized by poorly developed follicles that were heterogeneous in size with diminished colloid. Ciliated thyroid epithelial cells were observed in the transgenic thyroid glands, suggesting a failure of follicular cell differentiation. Consistent with this hypothesis, the DN CREB transgene inhibited the expression of an array of genes including thyroglobulin, thyroperoxidase, and the TSH receptor in semiquantitative RT-PCR experiments. Altered expression of the thyroid transcription factors Pax-8, TTF-1, and TTF-2 was also observed. These results demonstrate a critical role for CREB in thyroid growth, differentiation, and function in vivo.


Assuntos
Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Regulação da Expressão Gênica , Glândula Tireoide/fisiologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Calcitonina/análise , Bovinos , Diferenciação Celular , Linhagem Celular , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Camundongos Transgênicos , Regiões Promotoras Genéticas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Tireoglobulina/genética , Glândula Tireoide/citologia , Glândula Tireoide/ultraestrutura , Tireotropina/sangue , Tireotropina/genética , Tiroxina/sangue , Transfecção , Tri-Iodotironina/sangue
10.
Endocrinology ; 139(5): 2535-44, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9564869

RESUMO

The thyroid hormone receptor splice variant, alpha2, is unable to bind thyroid hormone (T3) and has been proposed to function as an endogenous inhibitor of T3 action. In this report, we examined further the DNA sequence requirements for alpha2 binding to thyroid hormone response elements (TREs) in an attempt to identify response elements that mediate potent inhibition by alpha2. Heterodimers of alpha2 and retinoid X receptor were found to bind to a subset of TREs (DR4, direct repeats spaced by 4 bp) in which selected flanking and spacer sequences enhanced interactions with the AGGTCA core binding sequence. Despite the optimization of the TRE-binding sites, alpha2 remained a weak dominant negative inhibitor of TRE-driven transcription. A promoter interference assay was also developed for testing inhibition by alpha2. In these studies, alpha2 blocked gene transcription, but it required cotransfected retinoid X receptor, and it was not as potent as unliganded thyroid hormone receptors. These results led to the hypothesis that alpha2 might be deficient in interactions with nuclear receptor corepressors. Consistent with this view, alpha2 did not silence basal transcription in its native form or when linked to Gal4. Alpha2 also failed to interact with corepressors (NCoR and SMRT) in both gel shift assays and mammalian two-hybrid assays. We conclude that alpha2 is a weak antagonist of thyroid hormone action because it binds weakly to a limited repertoire of response elements, and it does not interact with corepressors. Thus, alpha2 may be able to compete with thyroid hormone receptors for binding to a limited group of target sites, but it is not able to actively inhibit transcription.


Assuntos
Mutação , Receptores dos Hormônios Tireóideos/genética , Receptores dos Hormônios Tireóideos/metabolismo , Proteínas Repressoras/metabolismo , Tri-Iodotironina/antagonistas & inibidores , Sítios de Ligação , DNA/química , DNA/metabolismo , Dimerização , Humanos , Cinética , Regiões Promotoras Genéticas , Splicing de RNA , Receptores do Ácido Retinoico/química , Receptores do Ácido Retinoico/genética , Receptores dos Hormônios Tireóideos/química , Sequências Reguladoras de Ácido Nucleico , Receptores X de Retinoides , Fatores de Transcrição/química , Fatores de Transcrição/genética , Transfecção , Tri-Iodotironina/metabolismo
11.
Endocrinology ; 137(6): 2300-7, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8641179

RESUMO

GnRH regulates secretion of the gonadotropins, LH and FSH, in a sexually dimorphic manner. In the present study, we examined GnRH regulation of the gonadotropin alpha-subunit promoter to assess whether sex-dependent hormonal effects are manifest at the transcriptional level. Primary cultures of male or female rat pituitary cells were transfected with a reporter gene containing the alpha-promoter linked to luciferase (-420 alpha-LUC) and then subjected to treatment with GnRH for 24 h. Basal alpha-LUC expression was 4.2-fold greater in pituitary cells from males than in those from females. alpha-LUC activity was stimulated 5.3-fold by GnRH in males, whereas GnRH induced a 148-fold increase in alpha-promoter activity in females. The GnRH responsiveness of the transfected alpha-promoter did not vary in pituitary cells isolated at different stages of the female reproductive cycle, suggesting that acute changes in the hormonal milieu are not sufficient to alter transcriptional responses to GnRH. In males, orchidectomy minimally influenced alpha-LUC activity, indicating that testosterone does not exert a suppressive effect on GnRH responsiveness. In ovariectomized females, basal expression of alpha-LUC increased 3.7-fold, and GnRH stimulation was reduced from 165- to 11-fold, suggesting that an ovarian factor suppresses basal activity and enhances GnRH stimulation. Treatment of ovariectomized females with estrogen suppressed basal activity and restored GnRH stimulation of alpha-LUC, but the estrogen effects required long term treatment (10 days). Addition of progesterone to estrogen or treatment with the progesterone antagonist, RU486, had little effect on GnRH responsiveness. We conclude that estrogen exerts dual effects to suppress basal expression and to dramatically enhance GnRH responsiveness of the alpha-promoter. This model reveals potent actions of estrogen at the level of transcription and should provide new insights into the mechanisms that control estrogen priming of gonadotrope cells.


Assuntos
Estradiol/administração & dosagem , Subunidade alfa de Hormônios Glicoproteicos/genética , Hormônio Liberador de Gonadotropina/farmacologia , Caracteres Sexuais , Transcrição Gênica/efeitos dos fármacos , Animais , Células Cultivadas , Estradiol/farmacologia , Feminino , Luciferases/genética , Masculino , Orquiectomia , Ovariectomia , Regiões Promotoras Genéticas , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes de Fusão/metabolismo , Transfecção
12.
Endocrinology ; 136(7): 3146-53, 1995 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7789342

RESUMO

The hyt/hyt mouse is hypothyroid because of a mutation in the TSH receptor (TSH-R). In this report, we confirm the presence of a Pro to Leu mutation in amino acid 556 of the fourth transmembrane domain (TM4) of the TSH-R. This Pro is highly conserved in members of the G protein-coupled seven-transmembrane family of receptors. Insertion of this mutation into the wild-type rat receptor eliminated TSH binding and receptor function in transfected 293 and COS cells. Wild-type TSH-R conferred a 7.4-fold increase in cAMP and a 2.3-fold stimulation of a cAMP-responsive reporter gene. The P556L mutant receptor elicited no increase in cAMP or the reporter gene. Cells transfected with wild-type receptor bound TSH with a Kd of 3.3 x 10(-10) M, whereas no TSH binding was detected with the P556L mutant. Because the P556L mutation occurs in a receptor region (TM4) that is not expected to alter the binding of TSH, additional studies were performed to examine receptor processing and cellular localization. Mutant receptors from solubilized membranes also failed to bind TSH, indicating that the absence of binding to intact cells was not accounted for intracellular trapping of the mutant receptor. Western blot analyses demonstrated that the mutant and wild-type receptors were processed through a similar series of precursors and that a mature 95-kilodalton form of the mutant TSH-R was produced, consistent with its insertion into the plasma membrane. Immunofluorescence studies confirmed expression of the P556L mutant on the cell surface of transfected cells and in thyroid tissue from hyt/hyt mice. Although the extracellular domain of the TSH-R is sufficient for high affinity binding of TSH, we conclude that the hyt mutation in the fourth transmembrane domain eliminates TSH binding. These results suggest interactions between the extracellular and transmembrane domains of the TSH-R and indicate that this highly conserved proline is required for normal receptor structure and function.


Assuntos
Hipotireoidismo/genética , Leucina/genética , Mutagênese Sítio-Dirigida , Prolina/genética , Receptores da Tireotropina/genética , Tireotropina/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Western Blotting , Membrana Celular/metabolismo , Sequência Conservada , Imunofluorescência , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Receptores da Tireotropina/química , Receptores da Tireotropina/metabolismo , Relação Estrutura-Atividade
13.
J Clin Endocrinol Metab ; 85(8): 2779-85, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10946881

RESUMO

Mutations in the pituitary-specific paired-like homeodomain transcription factor, PROP-1, result in combined pituitary hormone deficiency. We studied a Brazilian girl, offspring of first cousins, who presented with short stature and deficiencies of GH, TSH, PRL, LH, and FSH. Her cortisol response to hypoglycemia was determined at age 4.9, 10.7, and 14.1 yr and remained normal. Magnetic resonance imaging at the age of 9 yr revealed an anterior pituitary lobe of diminished height (3 mm; normal, 4.5 +/- 0.6), but radiography revealed a sella turcica volume above the normal mean. Direct sequencing of the PROP-1 gene revealed homozygosity for a novel 263T>C transition that results in the replacement of a highly conserved phenylalanine by serine at codon 88 (F88S). F88 constitutes the hydrophobic core of the first helix of the homeodomain of PROP-1, and the substitution by the polar residue serine is expected to alter the secondary structure and impair binding of the mutated PROP-1 to DNA target sequences. The F88S mutation (which corresponds to murine F85S) was introduced into the murine Prop-1 complementary DNA and its consequences on DNA binding and trans-activation were assessed in vitro. In contrast to wild-type Prop-1, the F88S mutant showed no significant DNA binding to a PRDQ9 Prop-1 response element in gel shift assays. Transcriptional activation of a luciferase reporter gene containing a PRDQ9 site upstream of a simian virus 40 promoter was reduced to approximately 34% compared with that of wild-type Prop-1 in transiently transfected TSA-201 human embryonic kidney cells. The F88S mutation further expands the repertoire of mutations in PROP-1.


Assuntos
Proteínas de Homeodomínio/genética , Hipopituitarismo/genética , Hormônios Hipofisários/deficiência , Mutação Puntual , Sequência de Aminoácidos , Substituição de Aminoácidos , Sequência de Bases , Consanguinidade , Sequência Conservada , Feminino , Humanos , Hipopituitarismo/tratamento farmacológico , Hipopituitarismo/fisiopatologia , Lactente , Masculino , Fenilalanina , Hipófise/diagnóstico por imagem , Radiografia , Serina
14.
J Clin Endocrinol Metab ; 81(5): 1898-904, 1996 May.
Artigo em Inglês | MEDLINE | ID: mdl-8626855

RESUMO

In toxic thyroid adenomas, mutations in the TSH receptor (TSH-R) gene or the gene encoding the alpha-subunit of the stimulatory guanine nucleotide-binding protein (Gs alpha) have been demonstrated to constitutively activate the cAMP cascade, which subsequently stimulates the growth and function of these tumors. However, the widely varying thyroid phenotypes in patients with TSH-R germline mutations, ranging from only slightly enlarged diffuse to multinodular goiters, suggest that additional mechanisms may be effective in the pathogenesis of toxic adenomas. We have investigated the levels of stimulatory and inhibitory G protein alpha-subunits together with basal and TSH-stimulated adenylate cyclase (AC) activity in toxic adenomas with or without activating mutations and in nodular and extranodular tissues of a toxic goiter due to a germline mutation in the TSH-R gene. Augmented expression of Gs alpha protein was detected in all toxic adenomas, independent of the presence of mutations, and in the nodular tissue of the toxic goiter, but not in the nonnodular hyperplastic tissue of the toxic goiter with the mutated TSH-R. Analogously, the expression of the alpha-subunit of the inhibitory G protein (Gi alpha) was also increased in all adenomas and the nodular tissue of the goiter, but, again, not in the hyperplastic goiter tissue. Basal AC activity was high in all tissues with mutations, but was only slightly increased in adenomas without detected mutations. No correlation was detectable between basal or TSH-stimulated AC activity and the levels of Gs alpha and Gi alpha. Our data suggest that mutational activation of the cAMP cascade may not be sufficient to generate toxic nodules and adenomas, but far more complex mechanisms, including alterations of G protein signaling, may be effective in the pathogenesis of these tumors.


Assuntos
Adenoma/enzimologia , Adenilil Ciclases/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Neoplasias da Glândula Tireoide/enzimologia , Sequência de Bases , Análise Mutacional de DNA , Ativação Enzimática/efeitos dos fármacos , Proteínas de Ligação ao GTP/genética , Expressão Gênica , Humanos , Dados de Sequência Molecular , Mutação Puntual , Receptores da Tireotropina/genética , Tireotropina/farmacologia
15.
J Clin Endocrinol Metab ; 79(1): 134-9, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7517946

RESUMO

Although somatic mutations have been identified in a subset of thyroid nodules, the pathogenesis of nodules in multinodular goiters remains unclear. Clonal analysis indicates whether a nodule arises from the polyclonal proliferation of a group of cells or forms a clone from a genetically altered cell. Individual thyroid nodules have been shown to be of polyclonal or monoclonal origin. In this study we examined the clonality of several different nodules in patients with multinodular goiters. Clonality was established using the X-chromosomal probe M27 beta, which detects a multiallelic polymorphism at the locus DXS255 in 90% of females. Twenty-five nodules from 9 multinodular goiters were analyzed; 9 nodules were polyclonal, and 16 were monoclonal. Three goiters contained only polyclonal nodules, whereas 3 contained only monoclonal nodules. Polyclonal and monoclonal nodules coexisted in 3 goiters. In 2 goiters, the monoclonal nodules were shown to derive from different progenitor cells. We conclude that polyclonal and monoclonal nodules may coexist in multinodular goiters and that monoclonal nodules can originate from different cells. The coexistence of polyclonal and monoclonal nodules suggests that different pathogenic mechanisms occur simultaneously or that monoclonal nodules emerge secondarily from a polyclonal population due to a growth advantage from a genetically altered cell.


Assuntos
Células Clonais , Bócio Nodular/genética , Adulto , Idoso , Southern Blotting , Sondas de DNA , Desoxirribonuclease HpaII , Desoxirribonucleases de Sítio Específico do Tipo II , Mecanismo Genético de Compensação de Dose , Feminino , Marcadores Genéticos , Bócio Nodular/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Fragmento de Restrição , Células-Tronco/patologia
16.
J Clin Endocrinol Metab ; 86(8): 3962-7, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11502839

RESUMO

Congenital hypothyroidism associated with thyroid hypoplasia can be caused by several genetic defects, including mutations in the TSHbeta-subunit, the TSH receptor, the G(s)alpha-subunit, and the transcription factor PAX8. Four girls with sporadic congenital hypothyroidism and hypoplastic thyroid glands were analyzed for mutations in PAX8 and TTF2 (FKHL15). Mutations in the coding region of the TSHbeta-subunit gene, the TSH receptor gene, and exons 8 and 9 of G(s)alpha had been excluded previously. Serum TSH concentrations were 150 mU/liter or more, TG levels were within normal limits, and thyroid autoantibodies were absent. Technetium scintigraphies did not reveal the presence of thyroid tissue, but ultrasonography documented hypoplastic, normally located glands. One patient was found to harbor a heterozygous transversion 119A-->C in exon 3 of PAX8 replacing a conserved glutamine by proline in the paired box domain (Q40P). Analysis of her family members revealed that her mother, who has a thyroid gland of normal size and mild, adult-onset autoimmune hypothyroidism, is also heterozygous for this mutation. Functional analyses of the PAX8 Q40P mutation showed impaired binding to a PAX8 response element and absent trans-activation of a thyroid peroxidase promoter luciferase reporter gene. These findings confirm the important role of PAX8 in the development of the thyroid, but they indicate that PAX8 gene mutations may have a variable penetrance or expressivity. The absence of mutations in the coding sequences of the analyzed genes in the three other patients supports the concept that the pathogenesis of congenital hypothyroidism associated with thyroid hypoplasia is diverse.


Assuntos
Proteínas de Ligação a DNA/genética , Hipotireoidismo/genética , Proteínas Nucleares , Glândula Tireoide/anormalidades , Transativadores/genética , Sequência de Aminoácidos , Substituição de Aminoácidos , Sequência de Bases , Linhagem Celular , Hipotireoidismo Congênito , Proteínas de Ligação a DNA/química , Éxons , Feminino , Subunidades alfa Gs de Proteínas de Ligação ao GTP/genética , Impressão Genômica , Humanos , Hipotireoidismo/sangue , Recém-Nascido , Masculino , Modelos Moleculares , Fator de Transcrição PAX8 , Fatores de Transcrição Box Pareados , Linhagem , Fenótipo , Regiões Promotoras Genéticas , Estrutura Secundária de Proteína , Receptores da Tireotropina/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Tireoglobulina/sangue , Glândula Tireoide/diagnóstico por imagem , Tireotropina/sangue , Tireotropina/genética , Transativadores/química , Fatores de Transcrição/genética , Transfecção , Ultrassonografia
17.
J Clin Endocrinol Metab ; 77(3): 846-51, 1993 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8370709

RESUMO

Thirty-nine thyroid nodules, removed because of recent growth, were analyzed morphologically by serial histological sections for the classical histomorphological hallmarks of follicular cell replication and for immunohistochemically demonstrable overexpression of the growth-associated ras-gene product p21ras. Clonal analysis was performed using the highly informative probe M27 beta that detects polymorphisms on the locus DXS255 of the X-chromosome. Twenty-four nodules were of clonal and 15 nodules were of poly-clonal origin. Only 3 out of the 24 clonal nodules were histomorphologically uniform. In all others, the structural hallmarks of active growth and the P21ras growth-marker expression were remarkably heterogeneous throughout the tumors. There were no histomorphological characteristics distinguishing these clonal tumors from polyclonal nodules. Even if a clonal thyroid tumor may be originally homogeneous in respect to the parameters studied here, mechanisms must exist that create wide heterogeneity of growth and of morphogenetic potential among the individual follicular cells during further expansion of the nodule. Thus, clonal nodules are much more common in nodular goiters than hitherto assumed on grounds of the classical morphological criteria. The diagnosis of a true monoclonal nodule can no longer rely on morphological and functional criteria alone but requires molecular or cytogenetic analysis of clonality.


Assuntos
Nódulo da Glândula Tireoide/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Células Clonais/patologia , Feminino , Humanos , Técnicas Imunoenzimáticas , Pessoa de Meia-Idade , Polimorfismo Genético , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Nódulo da Glândula Tireoide/genética , Nódulo da Glândula Tireoide/metabolismo , Cromossomo X
18.
J Clin Endocrinol Metab ; 84(1): 336-41, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9920104

RESUMO

Pendred's syndrome is an autosomal recessive disease characterized by goiter, impaired iodide organification, and congenital sensorineural deafness. The gene mutated in Pendred's syndrome, PDS (Pendred's syndrome gene), was cloned very recently and encodes the putative sulfate transporter pendrin. Pendred's syndrome may account for up to 10% of the cases with hereditary hearing loss, and pendrin mutations have also been found in a kindred with non-syndromic deafness. In this study, 41 individuals from a large, highly inbred pedigree from Northeastern Brazil were examined for features of Pendred's syndrome. Linkage studies and sequence analysis of the coding region of the PDS gene were performed with DNA from 36 individuals. The index patient, with the classical triad of deafness, positive perchlorate test, and goiter, was found to be homozygous for a deletion of thymidine 279 in exon 3, resulting in a frameshift and a premature stop codon at amino acid 96. This alteration resulted in truncation of the protein in the first transmembrane domain. Two other patients with deafness were found to be homozygous for this mutation; 19 were heterozygous and 14 were homozygous for the wild type allele. Surprisingly, 6 deaf individuals in this kindred were not homozygous for the PDS gene mutation; 3 were heterozygous and 3 were homozygous for the wild type allele, suggesting a probable distinct genetic cause for their deafness. All 3 homozygous individuals for the PDS mutation had goiters. However, goiters were also found in 10 heterozygous individuals and in 6 individuals without the PDS mutation and are most likely caused by iodine deficiency. In conclusion, we identified a novel mutation in the PDS gene causing Pendred's syndrome. The comparison of phenotype and genotype reveals, however, that phenocopies generated by distinct environmental and/or genetic causes are present in this kindred and that the diagnosis of Pendred's syndrome may be difficult without molecular analysis.


Assuntos
Proteínas de Transporte/genética , Surdez/genética , Bócio/genética , Proteínas de Membrana Transportadoras , Mutação , Adulto , Brasil , DNA/química , Feminino , Ligação Genética , Genótipo , Humanos , Masculino , Fenótipo , Transportadores de Sulfato , Síndrome
19.
Eur J Cancer ; 38(12): 1607-10, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12142049

RESUMO

Conventional radiotherapy after breast-conserving therapy is confined to 50-55 Gy external beam radiation therapy (EBRT) to the whole breast and 10-16 Gy external boost radiation to the tumour bed or brachytherapy to the tumour bed. Local recurrence rate after breast-conserving surgery varies between 5 and 18%. External boost radiation can partially miss the tumour bed and therefore can result in local failure. Intra-operative radiotherapy (IORT) as a high precision boost can prevent a 'geographical miss'. From October 1998 to December 2000, 156 patients with stage I and stage II breast cancer were operated upon in a dedicated IORT facility. After local excision of the tumour, the tumour bed was temporarily approximated by sutures to bring the tissue in the radiation planning target volume. A single dose of 9 Gy was applied to the 90% reference isodose with energies ranging from 4 to 15 MeV, using round applicator tubes 4-8 cm in diameter. After wound healing, the patients received additional 51-56 Gy EBRT to the whole breast. No acute complications associated with IORT were observed. In 5 patients, a secondary mastectomy had to be performed because of tumour multicentricity in the final pathological report or excessive intraductal component. 2 patients developed rib necroses. In 7 patients, wound healing problems occurred. After a mean follow-up of 18 months, no local recurrences were observed. Cosmesis of the breast was very good and comparable to patients without IORT. Preliminary data suggest that IORT given as a boost after breast-conserving surgery could be a reliable alternative to conventional postoperative fractionated boost radiation by accurate dose delivery and avoiding geographical misses, by enabling smaller treatment volumes and complete skin-sparing and by reducing postoperative radiation time by 7-14 days.


Assuntos
Neoplasias da Mama/radioterapia , Carcinoma Ductal de Mama/radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/cirurgia , Carcinoma Ductal de Mama/cirurgia , Terapia Combinada , Feminino , Humanos , Cuidados Intraoperatórios/métodos , Mastectomia Segmentar/métodos , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/prevenção & controle , Estudos Prospectivos , Resultado do Tratamento
20.
Am J Med ; 79(5B): 141-5, 1985 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-4073082

RESUMO

A controlled, randomized study to compare the efficacy and safety of ticarcillin plus clavulanic acid with moxalactam was carried out in 25 evaluable patients with bone, joint, and skin or skin structure infections. Of the 13 patients in the ticarcillin plus clavulanic acid-treated group, nine had osteomyelitis, two had septic arthritis, one had cellulitis, and one had a wound infection. Four of the 12 moxalactam-treated patients had osteomyelitis, one had septic arthritis, and the other seven had cellulitis and/or infected ulcers. A total of 21 causative organisms were isolated in the group treated with ticarcillin plus clavulanic acid: Enterobacteriaceae (10), Pseudomonas aeruginosa (five), obligate anaerobes (three), Staphylococcus aureus (two), and Acinetobacter species (one). Cultures in the moxalactam-treated group yielded 23 pathogens: Enterobacteriaceae (seven), S. aureus (six), group B streptococci (four), P. aeruginosa (two), obligate anaerobes (two), Streptococcus pyogenes (one), and Aeromonas species (one). A cure or satisfactory response was achieved in 12 of the 13 (92 percent) patients who received ticarcillin plus clavulanic acid and in 10 of the 12 (83 percent) patients who received moxalactam. One patient with septic arthritis who received ticarcillin plus clavulanic acid had a relapse during therapy, as did one moxalactam-treated patient with a post-surgical wound infection. The other patient in whom moxalactam treatment failed had a wound infection that became reinfected. Some abnormalities in laboratory parameters occurred in each group, but none was severe enough to warrant discontinuation of treatment.


Assuntos
Artrite Infecciosa/tratamento farmacológico , Infecções Bacterianas/tratamento farmacológico , Ácidos Clavulânicos/administração & dosagem , Moxalactam/uso terapêutico , Osteomielite/tratamento farmacológico , Penicilinas/administração & dosagem , Dermatopatias Infecciosas/tratamento farmacológico , Ticarcilina/administração & dosagem , Adulto , Celulite (Flegmão)/tratamento farmacológico , Ácido Clavulânico , Combinação de Medicamentos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
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