Made available in DSpace on 2014-10-09T12:24:23Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:23Z (GMT). No. of bitstreams: 1 01060.pdf: 2681798 bytes, checksum: 846faeb39305ad029058cc97af9641b7 (MD5) / Tese (Doutoramento) / IEA/T / Faculdade de Medicina, Universidade de Sao Paulo - FM/USP

The osmoregulatory function of the larval recta of two saline-water mosquitoes, Aedes campestris and A. taeniorhynchus, was examined. In hyperosmotic waters the rectum was shown to be the site of formation of a concentrated urine by secretion of a hyperosmotic fluid into the rectal lumen. In similar concentrations of sea water, both species produced a rectal secretion having an osmotic concentration and ionic composition similar to that of sea water, with the exception that potassium levels are elevated 18- to 21-fold in the secretion. Osmoregulatory strategies in both species involve the rapid ingestion of the external medium. In taeniorhynchus this drinking rate, (100 nl mg⁻¹ h⁻¹ ) did not vary significantly in salinities between 10% and 200% sea water. It is suggested that two purposes are served by a rapid rate of drinking; 1) dissolved nutrients can be taken up when particulate food is limited and 2) when the uptake of external medium is large relative to the loss of water by osmosis across the cuticle, the concentration of urine necessary to maintain osmotic homeostasis is close to that of the external medium. Rectal function is A. campestris was examined in three media, all with an osmotic concentration of 700 mOsm but varying in their ionic ratios. These media contained the ionic ratios found in sea water and two types of ponds in which A. campestris naturally occur. The larvae were able to survive in all three media, suggesting that the larvae found in one saline environment are not physiologically limited to those ionic conditions. I demonstrated that changes in the relative transport rates of ions in the rectum are very significant in the acclimation process. The rectum was found to be the major site of Na⁺ , K⁺ , Mg⁺⁺, CI⁻ and probably HCO⁻₃ excretion, while the Malpighian tubules are the source of some of the magnesium and almost all of the sulphate in the urine. The ion ratios, exclusive of K⁺ found in the rectal secretion matched those in the external medium, with the exception that an unidentified anion (probably HC0~) substituted for SO₄̿ in (Na + Mg) SO₄̿ medium. A model is proposed showing the sites of ion secretion and uptake in the Malpighian tubules, rectum and anal papillae in all three media. Rectal function in A. taeniorhynchus larvae was examined in 10%, 100% and 200% sea water. In hyposmotic media the rectum does not secrete a fluid and it is postulated that salt and water resorption occur in the rectum under these conditions as in strictly freshwater species. In hyperosmotic media the concentrations of Na⁺ , K⁺ , Mg++ and Cl⁻ as well as the osmotic concentration of the secreted fluid increase with increasing external salinity. Due to the high rate of K+ secretion by the rectum, potassium uptake by the anal papillae is postulated. Sodium and chloride may be excreted at this site as well. An examination of the effect of varying hemolymph concentrations of sodium and chloride on the rate of secretion of these ions in the rectum, showed an allosteric relationship rather than the Michaelis-Mentin kinetics observed with most transport processes (e.g. the Mal-pighian tubules). An in vitro preparation (lacking tracheal and neural con* nections) of the larval rectum of A. taeniorhynchus was used to examine the function of the anterior and posterior rectal segments. These two regions, which differ morphologically, were shown to have separate functions in. vitro, the posterior segment secreting a hyperosmotic fluid while the fluid in the lumen of the anterior segment decreased in osmotic concentration and showed no change in volume. Electrical potential differences were measured across the basal and apical membranes as well as across the entire rectal wall in vivo. Based on these observations in artificial hemolymphs of various ionic compositions, a model is presented of ion transport processes occuring in the posterior rectal segments during the secretion of a hyperosmotic fluid. The model accounts for the ion concentrations and ionic ratios observed in rectal secretion from larvae reared in different media. / Science, Faculty of / Zoology, Department of / Graduate

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Despite the fact that high sodium intake has been linked to high blood pressure and an increased risk for cardiovascular disease (CVD), sufficient and irrevocable evidence to support extremely low dietary sodium intake has been lacking. The best method used for the estimation of daily sodium intake is indirectly by using 24-hour urinary sodium excretion, combined with para-aminobenzoic acid (PABA), which is used for validating completeness of urinary collection. However, the PABA validation method is not favored among researchers and the validity of high-performance liquid chromatography (HPLC) analysis for PABA has not been evaluated in a large-scale study. This study validated an improved PABA HPLC method and applied it in the sub-set of the Prospective Urban Rural Epidemiology (PURE) – 24-hour Urinary Excretion (24USE) Study for the examination of the sodium-blood pressure association. In addition, participants’ self-reported assessment of urinary collection completeness was compared to the PABA method. The HPLC analysis method for measuring PABA levels was downscaled and the reaction time lengthened to achieve higher through-put and reaction yield. By applying the optimized PABA method for evaluating urinary completeness, 612 of 681 participants’ samples contained 70%-110% PABA recovery and were extracted from the PURE24USE Study for further analysis. The average adjusted sodium excretion or intake was 3,673 ± 1,637 mg/day. The participants’ self-reports predict urinary collection completeness as measured by PABA with a sensitivity of 76.9% (95% CI: 74.4%-79.6%) and specificity of 31.7% (95% CI: 27.0%-36.4%). This moderate agreement suggests that PABA still has to be considered the gold standard, until further convincing evidence is available that self-report is more accurate than PABA. / Thesis / Master of Science in Medical Sciences (MSMS)

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yes / The aim of this study was to assess the relationship between pre-prostatectomy urinary Engrailed-2 (EN2), a transcription factor secreted by prostate cancer cells, with tumour volume and pathological characteristics in resected prostate specimens. First pass urine samples (10 ml) without prior prostatic massage were collected and stored at –80°C. EN2 levels were measured using an enzyme-linked immunoabsorbent assay. Tumour volume in the prostatectomy specimens was determined histologically. 57 men undergoing RP in one urological cancer network were evaluated. EN2 was detected in 85% of RP patients. EN2 correlated with tumour volume (but not total prostatic volume) in a linear regression analysis, with increasing pathological T stage and margin positivity. Using three “cutoff levels” of tumour volume (0.5 ml, 1.3 ml and 2.5 ml) to define “significant disease”, men with “significant disease” had markedly higher levels of urinary EN2 (p < 0.001 for each cut off level). Levels of urinary EN2 may be useful in predicting tumour volume in men with prostate cancer by potentially identifying men with small volume “insignificant” disease. This study justifies a larger multicentre evaluation of urinary EN2 levels as a biomarker of PC significance using cancer volume, pathological and PSA criteria.

OBJECTIF: Évaluer l’association entre les niveaux d’arsenic urinaire et la prévalence du diabète de type 2 dans la population canadienne. MÉTHODES : L’étude a concerné 3517 adultes participant à l’Enquête canadienne sur les mesures de santé réalisée de 2007 à 2009. Tous les participants ont eu une prise de sang pour la détermination du glucose et de l’hémoglobine glyquée ainsi qu’une analyse d’urine pour la détermination de l’arsenic total. De plus, ils ont répondu à un questionnaire détaillé sur leurs habitudes de vie et leurs antécédents médicaux. L’analyse statistique a utilisé la régression logistique multivariée. RÉSULTATS : L’As total urinaire est positivement associé au diabète de type 2 et au pré-diabète : Rapport de cotes ajusté de 1,81 (IC à 95%: 1,12 à 2,95) et 2,04 (IC à 95% CI: 1,02 à 4,07) respectivement. L’As total urinaire est aussi associé avec le taux d’hémoglobine glyquée chez les diabétiques non traités. CONCLUSION : L’association entre l’exposition à l’arsenic et la prévalence de diabète et de pré-diabète est observée dans la population canadienne. / OBJECTIVES: This study evaluated the association between As exposure, as measured by total As concentration in urine, and the prevalence of type 2 diabetes. METHODS: The study involved 3517 adults who participated in the Canadian Health Measures Survey (CHMS) carried out from 2007 to 2009. All participants had a blood test for glucose and glycated hemoglobin determination. Urine analysis was also performed for total arsenic determination. In addition, participants answered a detailed questionnaire about their lifestyle and medical history questionnaire. Statistical analysis was performed using multivariate logistic regression to identify significant relationships, while adjusting for potential confounders. RESULTS: Total urinary As is positively associated with type 2 diabetes and pre- diabetes: Adjusted odds ratio of 1.81 (95% CI: 1.12 to 2.95) and 2.04 (95% CI: 1.02 to 4.07), respectively. Total urinary As is also associated with glycated hemoglobin in untreated diabetics. CONCLUSIONS: The association between arsenic exposure and the prevalence of diabetes and pre-diabetes is observed in the Canadian population.

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