Sergio Aron Ajzen

Bio: Sergio Aron Ajzen is an academic researcher from Federal University of São Paulo. The author has contributed to research in topics: Magnetic resonance imaging & Endothelial dysfunction. The author has an hindex of 23, co-authored 108 publications receiving 1668 citations. Previous affiliations of Sergio Aron Ajzen include Vancouver General Hospital & University of British Columbia.

Effects of Low Birth Weight in 8- to 13-Year-Old Children Implications in Endothelial Function and Uric Acid Levels

Abstract: Low birth weight has been associated with an increased incidence of adult cardiovascular disease. Endothelial dysfunction and high levels of serum uric acid are associated with hypertension. In this study, we have determined whether uric acid is related to blood pressure and vascular function in children with low birth weight. We evaluated vascular function using high-resolution ultrasound, blood pressure, and uric acid levels in 78 children (35 girls, 43 boys, aged 8 to 13 years). Increasing levels of uric acid and systolic blood pressure were observed in children with low birth weight. Birth weight was inversely associated with both systolic blood pressure and uric acid; on the other hand, uric acid levels were directly correlated with systolic blood pressure in children of the entire cohort. Low birth weight was associated with reduced flow-mediated dilation ( r =0.427, P P= 0.040) had a graded inverse relationship with flow-mediated dilation, which was not affected in a model adjusting for race and gender. We conclude that children with a history of low birth weight show impaired endothelial function and increased blood pressure and uric acid levels. These findings may be early expressions of vascular compromise, contributing to susceptibility to disease in adult life.

Ultrasonography for the evaluation of visceral fat and cardiovascular risk.

Abstract: — —Visceral fat accumulation is associated with increased cardiovascular risk. Clinical evaluation of visceral fat is limited because of the lack of reliable and low-cost methods. To assess the correlation between ultrasonography and computed tomography (CT) for the evaluation of visceral fat, 101 obese women, age 50.5±7.7 years with a body mass index of 39.2±5.4 kg/m 2 , were submitted to ultrasonograph and CT scans. Visceral fat measured by ultrasonography, 1 cm above the umbilical knot, showed a high correlation with CT-determined visceral fat ( r =0.67, P r =0.29 and r =0.27, P r =0.22 and r =0.34, P r =0.18, P

Evaluation of Nephrolithiasis in Autosomal Dominant Polycystic Kidney Disease Patients

Abstract: Background and objectives: Nephrolithiasis (LIT) is more prevalent in patients with autosomal dominant polycystic kidney disease (ADPKD) than in the general population. Renal ultrasonography may underdetect renal stones because of difficulties imposed by parenchymal and/or cyst wall calcifications. Design, setting, participants, & measurements: A total of 125 patients with ADPKD underwent ultrasonography and unenhanced computed tomography (CT) scan, routine blood chemistry, and spot and 24-h urine collections. Results: CT scan detected calculi in 32 patients, including 20 whose previous ultrasonography revealed no calculi. The percentage of hypocitraturia was high but not statistically different between patients with ADPKD+LIT or ADPKD. Hyperuricosuria and distal renal tubular acidosis were less prevalent but also did not differ between groups, whereas hyperoxaluria was significantly higher in the former. Hypercalciuria was not detected. Renal volume was significantly higher in patients with ADPKD+LIT versus ADPKD, and a stepwise multivariate logistic regression analysis showed that a renal volume ≥500 ml was a significant predictor of LIT in patients with ADPKD and normal renal function, after adjustments for age and hypertension. Conclusions: CT scan was better than ultrasonography to detect LIT in patients with ADPKD. Larger kidneys from patients with ADPKD were more prone to develop stones, irrespective of the presence of metabolic disturbances.

Churg-Strauss syndrome: high resolution CT and pathologic findings.

Abstract: Objectives:The purpose of this study was to evaluate high-resolution CT findings in 7 patients with Churg-Strauss syndrome and to compare the CT with the histopathologic findings.Materials and Methods:High-resolution CT scans of 7 asthmatic patients (4 women, 3 men, age range, 34-62 years, mean 49 y

Diagnostic accuracy of sonography for pleural effusion: systematic review

Abstract: CONTEXTO E OBJETIVOS: O metodo inicial para a avaliacao da presenca dos derrames pleurais foi a radiografia de torax. Estudos isolados demonstraram que a ultrassonografia apresenta uma acuracia maior que a radiografia para este diagnostico, entretanto, nao se encontram disponiveis na literatura revisoes sistematicas sobre este tema. Assim, o objetivo deste estudo e avaliar a acuracia da ultrassonografia na deteccao de derrame pleural, por meio de revisao sistematica da literatura. TIPO DE ESTUDO E LOCAL: Revisao sistematica com metanalise de estudos de acuracia. O estudo foi conduzido no Departamento de Diagnostico por Imagem e no Centro Cochrane do Brasil/Disciplina de Medicina de Urgencia e Medicina Baseada em Evidencias do Departamento de Medicina, Universidade Federal de Sao Paulo (Unifesp), Sao Paulo, Brazil. METODOS: Foram pesquisadas as seguintes bases de dados: Cochrane Library, Medline, Web of Science, Embase e Literatura Latino-Americana e do Caribe em Ciencias da Saude (Lilacs). As referencias de estudos relevantes foram verificadas para adicionais citacoes de interesse. Foram incluidos estudos nos quais a acuracia da ultrassonografia para a deteccao de derrame pleural tenha sido testada, com padrao referencia aceitavel (tomografia computadorizada ou drenagem toracica). RESULTADOS: Foram incluidos quatro estudos. Todos apresentaram alta sensibilidade, especificidade e acuracia para a deteccao de derrame pleural pela ultrassonografia. A sensibilidade media foi de 93% (intervalo de confianca, IC 95%: 89% a 96%), e a especificidade 96% (IC 95%: 95% a 98%). CONCLUSOES: A ultrassonografia, em diferentes populacoes e cenarios clinicos, apresentou consistentemente alta sensibilidade, especificidade e acuracia na deteccao de liquido no espaco pleural.

Uric acid and cardiovascular risk.

Abstract: This review summarizes relevant studies concerning uric acid and possible links to hypertension, renal disease, and cardiovascular disease. Whether uric acid is an independent risk factor for such diseases is still a point of debate. Current evidence is presented.

Syndromes of the Head and Neck

Abstract: British authors are the natural heirs to Charles Dickens and Graham Greene.) Nevertheless there are advantages to British readers in a British book especially, for instance, in the chapter on social paediatrics and occasionally as regards therapeutics. The new Forfar and Arneil is, like its predecessors, a good book. There are many new authors and much of it has been completely rewritten. Each chapter has a long list of references, many of them to further reading in books and important 'landmark' papers rather than to very recent original work, and that seems appropriate for a textbook of this nature. It is up to date, including references to topics such as oesophageal pH monitoring in gastrooesophageal reflux, the value of steroids in bacterial meningitis, a full account of the peroxisomal disorders, the significance of dystrophin in muscular dystrophy, the importance of vitamin A in reducing mortality in third world countries, and the use of sumatriptan in migraine and of vigabatrin and lamotrigine in epilepsy. Surprisingly, neither in this nor in Nelson's textbook could I find any reference to Angelman's syndrome. Some topics chosen at random such as Prader-Willi syndrome or haemolytic uraemic syndrome were discussed more fully in the British textbook. There is a surprising omission, however, and that is the chapter on disorders ofear, nose, and throat. Adenoids, glue ear or secretory otitis media, tonsillitis, and tonsillectomy have all been dropped from the index and deafness is dealt with in the chapter on neurology. If you look up 'tonsils' you will be referred to any entry which reads: 'Tonsils: size, presence of infection, exudate, pitting, peritonsillar swelling?'. The index entry 'ear, nose and throat problems' refers to a brief account of such problems in children with cleft palate. It is one of those crazy facts of modern life that the American book costs £60, the British £125. Who will read this new edition? I shall, and I suppose many other consultant paediatricians will also use it as a standard reference book. Undergraduate students will need a more compact text for their basic reading but should use it to look up specific topics, and doctors studying for the MRCP in paediatrics should make a systematic assault on it to provide them with a personal database to be supplemented by journals and monographs. As a textbook of British paediatrics it has no competition and it remains an excellent work of reference which must be available in all paediatric departments in Britain, but the absence of the chapter on ear, nose, and throat disorders must surely be an error and there is clearly a marketing problem for British publishers faced with American competition. If we want British textbooks, and I would not like to think that the time will be forced upon us when we shall have no choice, then it looks as if we must be prepared to pay for the privilege. DOUG ADDY Consultant paediatrician

Acute Blood Pressure Lowering, Vasoprotective, and Antiplatelet Properties of Dietary Nitrate via Bioconversion to Nitrite

Abstract: Diets rich in fruits and vegetables reduce blood pressure (BP) and the risk of adverse cardiovascular events. However, the mechanisms of this effect have not been elucidated. Certain vegetables possess a high nitrate content, and we hypothesized that this might represent a source of vasoprotective nitric oxide via bioactivation. In healthy volunteers, approximately 3 hours after ingestion of a dietary nitrate load (beetroot juice 500 mL), BP was substantially reduced (Delta(max) -10.4/8 mm Hg); an effect that correlated with peak increases in plasma nitrite concentration. The dietary nitrate load also prevented endothelial dysfunction induced by an acute ischemic insult in the human forearm and significantly attenuated ex vivo platelet aggregation in response to collagen and ADP. Interruption of the enterosalivary conversion of nitrate to nitrite (facilitated by bacterial anaerobes situated on the surface of the tongue) prevented the rise in plasma nitrite, blocked the decrease in BP, and abolished the inhibitory effects on platelet aggregation, confirming that these vasoprotective effects were attributable to the activity of nitrite converted from the ingested nitrate. These findings suggest that dietary nitrate underlies the beneficial effects of a vegetable-rich diet and highlights the potential of a "natural" low cost approach for the treatment of cardiovascular disease.