Alteration in glucose metabolism in the brain associated with tamoxifen treatment: Study in postmenopausal animal model.

Tamoxifen is an effective breast cancer therapy in postmenopausal women. However, it can induce hyperglycemia through different mechanisms, such as the impairment of mitochondrial metabolism. Quercetin, a flavonoid with antioxidant potential, has beneficial effects on tamoxifen-induced adverse effects. Therefore, this study aimed to (1) investigate glucose concentration in blood, cerebrospinal fluid, cerebellum, cortex, and hippocampus of tamoxifen-treated ovariectomized female rats, non-treated and treated with quercetin; and (2) establish the metabolic profile of these regions. For that purpose, ovariectomized female rats were divided into four groups: canola oil 1 mL/kg (CONT); tamoxifen 5 mg/kg (TAM); quercetin 22.5 mg/kg (QUER); and tamoxifen 5 mg/kg + quercetin 22.5 mg/kg (TAM + Q); and were treated for 14 days orally. Subsequently, glucose levels were measured in blood, cerebrospinal fluid, cerebellum, cortex, and hippocampus. Pyruvate and lactate concentrations were analyzed in the three brain regions. Tamoxifen-induced hyperglycemia significantly increased glucose concentrations in the cerebrospinal fluid, cortex, and hippocampus, as well as lactate production in the hippocampus. Quercetin significantly prevented the tamoxifen-induced increase in glucose concentrations in all analyzed samples. Besides, quercetin decreased cortical pyruvate production. The copper content decreased only in the hippocampus of group TAM + Q animals. In addition, it is important to highlight that this study also observed that fourteen days of tamoxifen treatment strongly affects brain glucose metabolism, potentially disrupting normal brain functions. Therefore, this drug might represent a risk factor for postmenopausal women undergoing chemoprevention. Meanwhile, quercetin represents a potential intervention to promote metabolic regulation of glucose in tamoxifen-treated women.

Uric acid biorhythm, a feature of long-term variation in a clinical laboratory database.

BACKGROUND: The biorhythm of serum uric acid was evaluated in a large sample of a clinical laboratory database by spectral analysis and the influence of the gender and age on uric acid variability. METHODS: Serum uric acid values were extracted from a large database of a clinical laboratory from May 2000 to August 2006. Outlier values were excluded from the analysis and the remaining data (n=73,925) were grouped by gender and age ranges. Rhythm components were obtained by the Lomb Scargle method and Cosinor analysis. RESULTS: Serum uric acid was higher in men than in women older than 13 years (p<0.05). Compared with 0-12 year group, uric acid increased in men but not in women older than 13 years (p<0.05). Circannual (12 months) and transyear (17 months) rhythm components were detected, but they were significant only in adult individuals (>26 years, p<0.05). Cosinor analysis showed that midline estimating statistic of rhythm (MESOR) values were higher in men (range: 353-368 µmol/L) than in women (range: 240-278 µmol/L; p<0.05), independent of the age and rhythm component. The extent of predictable change within a cycle, approximated by the double amplitude, represented up to 20% of the corresponding MESOR. CONCLUSIONS: Serum uric acid biorhythm is dependent on gender and age and it may have relevant influence on preanalytical variability of clinical laboratory results.

Real-time PCR-based quantification of Toxoplasma gondii in tissue samples of serologically positive outdoor chickens.

This study aimed to quantify Toxoplasma gondii in tissue samples of serologically positive chickens using real-time polymerase chain reaction (PCR). Of 65 chickens evaluated, 28 were positive for T. gondii antibodies. Brain and heart samples were collected from 26 seropositive chickens and DNA was extracted using Trizol® and amplified using real-time PCR with SYBR® Green. Parasite DNA was detected in 24 of the 26 samples analyzed; the number of positive tissue samples and the parasite quantity did not differ between tissue types. The results confirmed the analytical sensitivity of parasite detection in chicken tissue samples and demonstrated the possibility of using other molecular systems for genotypic analysis.

17q22-24 chromosomal losses and alterations of protein kinase a subunit expression and activity in adrenocorticotropin-independent macronodular adrenal hyperplasia.

CONTEXT: Primary adrenocortical hyperplasias leading to Cushing syndrome include primary pigmented nodular adrenocortical disease and ACTH-independent macronodular adrenal hyperplasia (AIMAH). Inactivating mutations of the 17q22-24-located PRKAR1A gene, coding for the type 1A regulatory subunit of protein kinase A (PKA), cause primary pigmented nodular adrenocortical disease and the multiple endocrine neoplasia syndrome Carney complex. PRKAR1A mutations and 17q22-24 chromosomal losses have been found in sporadic adrenal tumors and are associated with aberrant PKA signaling. OBJECTIVE: The objective of the study was to examine whether somatic 17q22-24 changes, PRKAR1A mutations, and/or PKA abnormalities are present in AIMAH. PATIENTS: We studied fourteen patients with Cushing syndrome due to AIMAH. METHODS: Fluorescent in situ hybridization with a PRKAR1A-specific probe was used for investigating chromosome 17 allelic losses. The PRKAR1A gene was sequenced in all samples, and tissue was studied for PKA activity, cAMP responsiveness, and PKA subunit expression. RESULTS: We found 17q22-24 allelic losses in 73% of the samples. There were no PRKAR1A-coding sequence mutations. The RIIbeta PKA subunit was overexpressed by mRNA, whereas the RIalpha, RIbeta, RIIalpha, and Calpha PKA subunits were underexpressed. These findings were confirmed by immunohistochemistry. Total PKA activity and free PKA activity were higher in AIMAH than normal adrenal glands, consistent with the up-regulation of the RIIbeta PKA subunit. CONCLUSIONS: PRKAR1A mutations are not found in AIMAH. Somatic losses of the 17q22-24 region and PKA subunit and enzymatic activity changes show that PKA signaling is altered in AIMAH in a way that is similar to that of other adrenal tumors with 17q losses or PRKAR1A mutations.

Molecular and functional analysis of PRKAR1A and its locus (17q22-24) in sporadic adrenocortical tumors: 17q losses, somatic mutations, and protein kinase A expression and activity.

Germ-line protein kinase A (PKA) regulatory-subunit type-Ialpha (RIalpha; PRKAR1A)-inactivating mutations and loss-of-heterozygosity (LOH) of its 17q22-24 locus have been found in Cushing syndrome (CS) caused by primary pigmented nodular adrenocortical disease (PPNAD). We examined whether somatic 17q22-24, PRKAR1A, or PKA changes are present in 44 sporadic adrenocortical tumors (29 adenomas and 15 cancers); 26 of these tumors were responsible for CS. A probe containing the PRKAR1A gene-mapped by fluorescent in situ hybridization to 17q22-24-and corresponding microsatellite markers were used to study allelic losses; PRKAR1A was sequenced in all samples. 17q22-24 losses were seen in 23 and 53% of adenomas and cancers, respectively. In three tumors, somatic, PRKAR1A-inactivating mutations were identified: (a) a nonsense mutation in exon 6 (A751G); (b) a splicing mutation (9IVS-1G/A); and (c) a transition (1050T>C) followed by a 22-bp deletion, also in exon 9; all predicted premature RIalpha protein terminations. Quantitative message and protein studies showed RIalpha down-regulation in tumors with genetic changes; their cortisol secretion pattern was similar to that of PPNAD, and they had higher PKA activity by enzymatic studies. We conclude that somatic allelic losses of the 17q22-24 region, PRKAR1A-inactivating mutations or down-regulation, and corresponding PKA activity changes are present in at least some sporadic adrenocortical tumors, especially those with a PPNAD-like clinical presentation of CS.

Molecular cloning, chromosomal localization of human peripheral-type benzodiazepine receptor and PKA regulatory subunit type 1A (PRKAR1A)-associated protein PAP7, and studies in PRKAR1A mutant cells and tissues.

A mouse protein that interacts with the peripheral-type benzodiazepine receptor (PBR) and cAMP-dependent protein kinase A (PKA) regulatory subunit RIalpha (PRKAR1A), named PBR and PKA-associated protein 7 (PAP7), was identified and shown to be involved in hormone-induced steroid biosynthesis. We report the identification of the human PAP7 gene, its expression pattern, genomic structure, and chromosomal mapping to 1q32-1q41. Human PAP7 is a 60-kDa protein highly homologous to the rodent protein. PAP7 is widely present in human tissues and highly expressed in seminal vesicles, pituitary, thyroid, pancreas, renal cortex, enteric epithelium, muscles, myocardium and in steroidogenic tissues, including the gonads and adrenal cortex. These tissues are also targets of Carney complex (CNC), a multiple neoplasia syndrome caused by germline inactivating PRKAR1A mutations (PRKAR1A-mut) and associated with primary pigmented nodular adrenocortical disease (PPNAD) and increased steroid synthesis. PAP7 and PRKAR1A expression were studied in PPNAD and in lymphoblasts from patients bearing PRKAR1A-mut. Like PRKAR1A, PAP7 was decreased in CNC lymphocytes and PPNAD nodules, but not in the surrounding cortex. These studies showed that, like in the mouse, human PAP7 is highly expressed in steroidogenic tissues, where it follows the pattern of PRKAR1A expression, suggesting that it participates in PRKAR1A-mediated tumorigenesis and hypercortisolism.

Clinical and molecular genetics of primary pigmented nodular adrenocortical disease.

Carney complex (CNC) is a multiple endocrine neoplasia (MEN) syndrome associated with other, non-endocrine manifestations such as lentigines, cardiac myxomas and schwannomas. Primary pigmented nodular adrenocortical disease (PPNAD), leading to corticotrophin-independent Cushing's syndrome is the most frequent endocrine lesion in CNC. The complex has been mapped to 2p16 and 17q22-24, although additional heterogeneity may exist. The gene coding for the protein kinase A (PKA) type I-a regulatory subunit (RIa), PRKAR1A, had been mapped to 17q. Cloning of the PRKAR1A genomic structure and its sequencing showed mutations in CNC-, CNC with PPNAD- and sporadic PPNAD-patients. In CNC tumors, PKA activity showed increased stimulation by cAMP, whereas PKA activity ratio was decreased, and in CNC tumors, there is LOH of the normal allele, suggesting that normal PRKAR1A may be a tumor suppressor in these tissues. CNC is the first human disease caused by mutations of one of the subunits of the PKA enzyme, a critical component of the cAMP signaling system and a potential participant in many other signaling pathways.

[Childhood adrenocortical tumors]. / Tumores do córtex adrenal na infância.

Adrenocortical tumors (ACT) in children are uncommon. However, the incidence of these tumors in Paraná, Brazil, is 15 times higher than that worldwide. We describe the clinical, laboratory and treatment characteristics and outcome of 125 patients treated in a single institution in the State of Paraná. The median age at diagnosis was 4.3 years, with a female:male ratio of 2.6:1. The most common forms of presentation were isolated virilization (51.2%) and virilization and Cushing's syndrome (42%). Nonfunctioning tumors comprised 4.8% of the cases. Two patients (1.6%) had isolated Cushing's syndrome and 1 (0.8%) had Conn's syndrome. Fifty-six percent presented hypertension. Surgery is the only curative treatment. Our data show that disease stage 1, absence of spillage during surgery and absence of intravenous thrombus were associated with better survival rates.

Allele frequencies of 15 STRs in a representative sample of the Brazilian population.

Allele frequencies for 15 short tandem repeat (STR) loci were obtained from a sample of 12,030 individuals undergoing paternity testing. This sample includes individuals from all States in Brazil, combined according to the current country division into five regions (North, Northeast, Central West, Southeast, and South). The most polymorphic loci were D2S1338 and D18S51. All the analysed loci meet Hardy-Weinberg equilibrium expectations. Combined power of discrimination and combined power of exclusion for the 15 tested STR loci were 0.999999999999990 and 0.9999992, respectively. Comparative analysis between populations from different Brazilian macroregions as well as between Brazil and other relevant populations are presented.

Associação entre deficiência de vitamina D, adiposidade e exposição solar em participantes do sistema de hipertensão arterial e diabetes melito / Association between vitamin D deficiency, adiposity and solar exposure in participants with arterial hypertension and diabetes mellitus

Atualmente, diversos estudos demonstram uma relação entre deficiência de vitamina D e diabetes melito tipo 2, obesidade e hipertensão arterial. A principal causa de deficiência de vitamina D é a falta de exposição solar adequada. O objetivo deste estudo foi avaliar os níveis séricos de vitamina D e sua associação com ingestão de vitamina D, composição corporal e exposição solar em pacientes participantes do Sistema de Hipertensão e Diabetes da cidade de Cascavel, PR. Participaram 304 adultos e idosos, de ambos os sexos, e foram avaliados os dados demográficos e antropométricos, hábitos de vida, presença de doenças prévias, dietética e a dosagem de vitamina D sérica. Utilizou-se do teste qui quadrado para verificação de associação e aderência e o teste de Kruskal-Wallis para comparação de medianas entre as variáveis estudadas. Verificou-se deficiência sérica de 25-hidroxivitamina D [25(OH)D] (<20ng/mL) em 52,6%, excesso de peso em 73,4%, aumento na circunferência abdominal em 77,6% e na percentagem de gordura corporal em 95,6% dos pacientes. Não houve associação entre a ingestão e os níveis séricos de vitamina D. Houve associação significativa entre circunferência abdominal (p<0,05), hipertensão arterial (p>0,001) e exposição solar inadequada (p<0,001) com os diferentes níveis séricos de vitamina D. Os pacientes com níveis séricos desejáveis de vitamina D apresentaram menores valores de índice de massa corpórea (p<0,03), de circunferência abdominal (p<0,01) e maior tempo de exposição solar (p=0,01). Este estudo verificou uma alta frequência de hipovitaminose D, sendo esta, associada com a diminuição de exposição solar e com adiposidade.

Currently, several studies have shown a relationship between vitamin D deficiency and type 2 diabetes mellitus, obesity and hypertension. The major cause of vitamin D deficiency is the lack of adequate sun exposure. The objective of the study was to evaluate serum vitamin D level and to verify its association with vitamin D ingestion, body composition and solar exposure in patients participating in the Hypertension and Diabetes System in Cascavel, PR. A total of 304 adult and elder patients from both genders participated in the study. Demographic and anthropometric data, lifestyle, presence of previous diseases, dietary and serum levels of vitamin D were evaluated. We used the chi square test for association verification and compliance and the Kruskal-Wallis test to compare medians between variables. It was verified serum 25-hydroxyvitamin D (25(OH)D) deficiency (<20ng/mL) in 52.6%, overweight and obesity in 73.4%, increase in abdominal circumference in 77.6% and in body fatpercentage in 95.6% of the patients. There was no association between ingestion and serum vitamin D levels. Significant association was found between abdominal circumference (p<0.05), hypertension (p=0.0006) and inadequate solar exposure (p<0.001) with serum vitamin D different levels. There was a high frequency of hypovitaminosis D and association with lower solar exposure and adiposity.

15 STR loci frequencies in the population from Paraná, Southern Brazil.

Allele frequencies for 15 short tandem repeats (STR) loci were obtained from a sample of 4076 unrelated individuals undergoing paternity testing. The population is from Paraná, Southern Brazil. The loci are the most commonly used in forensic and paternity testing, being analyzed by the AmpFlSTR((R)) Identifiler (Applied Biosystems) commercial kit. The most polymorphic loci were D2S1338 and D18S51. Excepting the D13S317, all loci were in Hardy-Weinberg equilibrium. Comparative analyses between our population data and other populations are presented.

Risk factors for the development of atherosclerosis in childhood and adolescence.

Cardiovascular diseases (CVD) are a major cause of death in developed countries as well as in developing countries. In general, the clinical manifestations of CVD, such as myocardial infarction, stroke and peripheral vascular disease, are caused by an atherosclerotic process with onset as from the middle age. However, current studies indicate that the atherosclerotic process starts to develop in childhood. The pathogenesis of atherosclerosis has been studied as to its inflammatory aspect. Among the inflammatory markers, C-reactive protein (CRP) has been extensively studied in individuals with CVD, including those apparently healthy. High CRP levels have been related to risk factors for atherosclerosis: family history of coronary artery disease (CAD), dyslipidemia, hypertension, diabetes mellitus, obesity, smoking and sedentary lifestyle. A great part of these risk factors may be influenced by lifestyle modifications, such as changes in eating habits and engagement in physical activities. The effects of physical activity on CRP levels in adulthood are documented in the literature, however little is known on the influence of an active or sedentary lifestyle of children and adolescents on CRP levels. Thus, the objective of this study is to review the impact of physical activity of children and adolescents on CRP levels and the risk factors for the development of CVD.

Childhood adrenocortical tumours: a review.

Childhood adrenocortical tumour (ACT) is not a common disease, but in southern Brazil the prevalence is 15 times higher than in other parts of the world. One hundred and thirty-seven patients have been identified and followed by our group over the past four decades. Affected children are predominantly girls, with a female-to-male ratio of 3.5:1 in patients below 4 years of age. Virilization alone (51.6%) or mixed with Cushing's syndrome (42.0%) was the predominant clinical picture observed in these patients. Tumours are unilateral, affecting both glands equally. TP53 R337H germline mutations underlie most childhood ACTs in southern Brazil. Epidemiological data from our casuistic studies revealed that this mutation has ~10% penetrance for ACT. Surgery is the definitive treatment, and a complete resection should always be attempted. Although adjuvant chemotherapy has shown some encouraging results, its influence on overall outcome is small. The survival rate is directly correlated to tumour size; patients with small, completely excised tumours have survival rates close to 90%, whereas in those patients with inoperable tumours and/or metastatic disease it is less than 10%. In the group of patients with large, excisable tumours, half of them have an intermediate outcome. Recent molecular biology techniques and genomic approaches may help us to better understand the pathogenesis of ACT, the risk of developing a tumour when TP53 R337H is present, and to predict its outcome. An ongoing pilot study consisting of close monitoring of healthy carriers of the TP53 R337H mutation - siblings and first-degree relatives of known affected cases - aims at the early detection of ACTs and an improvement of the cure rate.

Deficiência de ferro, prevalência de anemia e fatores associados em crianças de creches públicas do oeste do Paraná, Brasil / Iron deficiency and prevalence of anemia and associated factors in children attending public daycare centers in western Paraná, Brazil

OBJETIVO: Avaliar o estado nutricional de ferro, a prevalência de anemia e fatores associados, em crianças de 6 a 24 meses frequentadoras de creche pública em Cascavel, Região Oeste do Paraná, Brasil. MÉTODOS: O estudo transversal foi realizado com amostra aleatória de 256 crianças. A coleta de dados (questionário, medidas antropométricas e amostras de sangue) ocorreu de julho a setembro de 2007. A deficiência de ferro foi avaliada em termos de transferrina, hemoglobina, volume corpuscular médio, ferro sérico e eosinófilos. Na análise estatística dos dados foram obtidas as odds ratio bruta e ajustada (regressão logística), bem como os respectivos níveis de significância (p-valor). Para identificar diferenças significativas entre as medidas quantitativas, adotou-se a Análise de Variância e o teste de comparação múltipla de Tukey. RESULTADOS: A prevalência da anemia foi de 29,7 por cento, sendo que 77,3 por cento das amostras apresentaram baixa concentração de ferro. A antropometria não apontou deficiência de macronutrientes, porém mostrou obesidade acima dos índices médios. Os fatores associados à anemia e à deficiência de ferro foram: doenças frequentes na família (OR=10,02), condições de moradia (OR=5,05), tempo de creche (OR=3,05), número de moradores na residência (OR=2,83) e falta de saneamento (OR=2,20). CONCLUSÃO: A prevalência de anemia e a elevada deficiência de ferro detectada evidenciam um grave problema de saúde pública entre os pré-escolares do município de Cascavel, Paraná. Apesar da amplitude do problema, a anemia não está sendo reconhecida, prevenida e tratada adequadamente. Neste estudo são sugeridas algumas possíveis intervenções.

OBJECTIVE: This study assessed the iron levels and prevalence of anemia and associated factors in children aged 6 to 24 months attending public daycare centers in Cascavel, Western Paraná, Brazil. METHODS: This cross-sectional study included 256 randomly sampled children. Questionnaires were administered and anthropometric data and blood samples were collected from July to September 2007. Iron status was determined by measuring transferrin level, hemoglobin level, mean corpuscular volume, serum iron level and eosinophil count. Crude and adjusted (logistic regression) odds ratios and the respective significance levels (p-value) were obtained by statistical analysis. Analysis of variance and the Tukey's range test were used for identifying significant differences in the quantitative measurements. RESULTS: There was a 29.7 percent prevalence of anemia and 77.3 percent of the sample presented low iron levels. Anthropometry did not indicate macronutrient deficiencies but revealed above-average obesity rates. The factors associated with anemia and iron deficiency were family members constantly becoming sick (OR=10.02), poor living conditions (OR=5.05), time attending a daycare center (OR=3.05), number of individuals in the household (OR=2.83) and absence of sanitation (OR=2.20). CONCLUSION: The prevalence of anemia and the high iron deficiency rate evidenced a severe public health problem regarding the preschool children from Cascavel, Paraná. Despite the magnitude of the problem, anemia is not being detected, prevented and treated properly. This study suggests some possible interventions.

Real-time PCR-based quantification of Toxoplasma gondii in tissue samples of serologically positive outdoor chickens

This study aimed to quantify Toxoplasma gondii in tissue samples of serologically positive chickens using real-time polymerase chain reaction (PCR). Of 65 chickens evaluated, 28 were positive for T. gondii antibodies. Brain and heart samples were collected from 26 seropositive chickens and DNA was extracted using Trizol® and amplified using real-time PCR with SYBR® Green. Parasite DNA was detected in 24 of the 26 samples analyzed; the number of positive tissue samples and the parasite quantity did not differ between tissue types. The results confirmed the analytical sensitivity of parasite detection in chicken tissue samples and demonstrated the possibility of using other molecular systems for genotypic analysis.

Clinical and molecular genetics of Carney complex.

Carney complex (CNC) is a multiple endocrine neoplasia (MEN) syndrome characterized by lentigines, cardiac myxomas and tumors, including primary pigmented adrenocortical disease (PPNAD). In the present report we review the main clinical manifestations of this disorder. We also discuss some of the newest molecular information regarding CNC. The complex has been mapped to 2p16 and 17q22-24, and a third locus appears likely. The gene coding for the protein kinase A (PKA) type I-a regulatory subunit (RIa), PRKAR1A, had been mapped to 17q. Cloning of the PRKAR1A genomic structure and its sequencing showed mutations in CNC patients. So far, among 57 kindreds, PRKAR1A mutations have been found in 28. In almost all the mutations, the sequence change is predicted to lead to a premature stop codon; 1 mutation altered the initiator ATG codon. Analysis of mRNA transcripts in patient lymphocytes treated with cycloheximide showed that mutant mRNAs containing a premature stop codon were degraded, due to nonsense-mediated mRNA decay--the predicted mtPRKAR1A protein products were absent in these cells. In CNC tumors, PKA activity showed increased stimulation by cAMP, whereas PKA activity ratio was decreased. To date, mutations in the PRKAR1A gene have been described in CNC patients and in some sporadic endocrine tumors. LOH of the normal allele and increased PKA activity in response to cAMP are found in these tumors, suggesting that normal PRKAR1A (largely responsible for PKA type I activity) is implicated more widely in endocrine tumorigenesis. CNC is the first human disease caused by mutations of one of the subunits of the PKA holoenzyme, a critical component of numerous cellular signaling systems.

Protein kinase-A activity in PRKAR1A-mutant cells, and regulation of mitogen-activated protein kinases ERK1/2.

Carney complex (CNC) is caused by PRKAR1A-inactivating mutations. PRKAR1A encodes the regulatory subunit type I-alpha (RIalpha) of the cAMP-dependent kinase (PKA) holoenzyme; how RIalpha insufficiency leads to tumorigenesis remains unclear. In many cells PKA inhibits the extracellular receptor kinase (ERK1/2) cascade of the mitogen-activated protein kinase (MAPK) pathway leading to inhibition of cell proliferation. We investigated whether the PKA-mediated inhibitory effect on ERK1/2 is affected in CNC cells that carry germline PRKAR1A mutations. PKA activity both at baseline and after stimulation with cAMP was augmented in cells carrying mutations. Quantitative message analysis showed that the main PKA subunits expressed were type I (RIalpha and RIbeta) but RIalpha was decreased in mutant cells. Immunoblot assays of ERK1/2 phosphorylation by the cell- and pathway-specific stimulant lysophosphatidic acid (LPA) showed activation of this pathway in a time- and concentration-dependent manner that was prevented by a specific inhibitor. There was a greater rate of growth in mutant cells; forskolin and isoproterenol inhibited LPA-induced ERK1/2 phosphorylation in normal but not in mutant cells. Forskolin inhibited LPA-induced cell proliferation and metabolism in normal cells, but stimulated these parameters in mutant cells. These data were also replicated in a pituitary tumor cell line carrying the most common PRKAR1A mutation (c.578del TG), and an in vitro construct of mutant PRKAR1A that was recently shown to lead to augmented PKA-mediated phosphorylation. We conclude that PKA activity in CNC cells is increased and that its stimulation by forskolin or isoproterenol increases LPA-induced ERK1/2 phosphorylation, cell metabolism and proliferation. Reversal of PKA-mediated inhibition of this MAPK pathway in CNC cells may contribute to tumorigenesis in this condition.

Regulatory subunit type I-alpha of protein kinase A (PRKAR1A): a tumor-suppressor gene for sporadic thyroid cancer.

The tumor-suppressor gene encoding the cyclic AMP-dependent protein kinase A type I-alpha regulatory subunit PRKAR1A has been mapped to chromosome 17 (17q22-24) and is mutated in Carney complex, a familial neoplasia syndrome that is associated with thyroid tumors. Other genes implicated in cyclic nucleotide-dependent signaling have been investigated in thyroid tumorigenesis. We studied protein kinase A (PKA) activity in noninherited follicular thyroid adenomas and follicular, papillary, and undifferentiated (anaplastic) thyroid carcinomas. We then examined these and additional thyroid tumors for losses of the 17q22-24 PRKAR1A region, mutations of the PRKAR1A gene, and expression of its peptide product. Total PKA activity was markedly increased in carcinomas over that in adenomas, whereas the ratio of free vs. total PKA activity was decreased in cancer. Consistent with these findings, the 17q22-24 region was frequently lost in cancer but not in benign adenomas. A novel inactivating mutation of the PRKAR1A gene (leading to premature termination of the predicted protein) was found in an aggressive thyroid cancer. The tumor with PRKAR1A gene mutation, as well as the tumors with 17q allelic losses, showed decreased PRKAR1A expression by immunostaining. We conclude that PRKAR1A, the most abundant regulatory subunit of protein kinase A and a principal cyclic AMP-signaling modulator, acts as a tumor-suppressor gene in sporadic thyroid cancer. Published 2002 Wiley-Liss, Inc.

Eyelid myxoma in Carney complex without PRKAR1A allelic loss.

Eyelid nodules were investigated in a patient with Carney complex who was heterozygous for the most commonly known PRKAR1A-inactivating mutation, c.578delTG. Immunohistochemical studies confirmed the diagnosis of myxoma. Loss of heterozygosity was not present, suggesting that haploinsufficiency alone was responsible for tumorigenesis of this eyelid lesion.

Fatores de risco no desenvolvimento da aterosclerose na infância e adolescência / Risk factors for the development of atherosclerosis in childhood and adolescence

As doenças cardiovasculares (DCV) constituem uma importante causa de morte nos países desenvolvidos e também naqueles em desenvolvimento. Em geral, as manifestações clínicas das DCV, como infarto do miocárdio, acidente vascular encefálico e doença vascular periférica, são causadas por um processo aterosclerótico e têm início a partir da meia-idade. No entanto, estudos atuais indicam que o processo aterosclerótico começa a se desenvolver na infância. A fisiopatogenia da aterosclerose tem sido estudada pelo seu aspecto inflamatório, e, dentre os marcadores inflamatórios, a proteína-C-reativa (PCR) vem sendo bastante estudada nos indivíduos portadores de alguma DCV, inclusive naqueles aparentemente saudáveis. Níveis elevados de PCR têm sido relacionados a fatores de risco para a aterosclerose: história familiar de doença arterial coronariana (DAC), dislipidemia, hipertensão arterial, diabete melito, obesidade, tabagismo e sedentarismo. Grande parte desses fatores de risco pode ser influenciada por modificações no estilo de vida, tais como a mudança de hábitos alimentares e a prática de atividade física. Na literatura estão documentados os efeitos da atividade física sobre os níveis de PCR na fase adulta, porém há pouco conhecimento dos estilos de vida ativo ou sedentário em crianças e adolescentes. Este trabalho tem o objetivo de revisar o impacto da atividade física em crianças e adolescentes sobre os níveis de PCR e os fatores de risco para o desenvolvimento de DCV.

Cardiovascular diseases (CVD) are a major cause of death in developed countries as well as in developing countries. In general, the clinical manifestations of CVD, such as myocardial infarction, stroke and peripheral vascular disease, are caused by an atherosclerotic process with onset as from the middle age. However, current studies indicate that the atherosclerotic process starts to develop in childhood. The pathogenesis of atherosclerosis has been studied as to its inflammatory aspect. Among the inflammatory markers, C-reactive protein (CRP) has been extensively studied in individuals with CVD, including those apparently healthy. High CRP levels have been related to risk factors for atherosclerosis: family history of coronary artery disease (CAD), dyslipidemia, hypertension, diabetes mellitus, obesity, smoking and sedentary lifestyle. A great part of these risk factors may be influenced by lifestyle modifications, such as changes in eating habits and engagement in physical activities. The effects of physical activity on CRP levels in adulthood are documented in the literature, however little is known on the influence of an active or sedentary lifestyle of children and adolescents on CRP levels. Thus, the objective of this study is to review the impact of physical activity of children and adolescents on CRP levels and the risk factors for the development of CVD.