Effect of Ocean Acidification on the Speciation of Metals in Seawater

Increasing atmospheric CO2 over the next 200 years will cause the pH of ocean waters to decrease further. Many recent studies have examined the effect of decreasing pH on calcifying organisms in ocean waters and on other biological processes (photosynthesis, nitrogen fixation, elemental ratios, and community structure). In this review, we examine how pH will change the organic and inorganic speciation of metals in surface ocean waters, and the effect that it will have on the interactions of metals with marine organisms. We consider both kinetic and equilibrium processes. The decrease in concentration of OH- and CO32- ions can affect the solubility, adsorption, toxicity, and rates of redox processes of metals in seawater. Future studies are needed to examine how pH affects the interactions of metals complexed to organic ligands and with marine organisms

Effect of Ocean Acidification on the Speciation of Metals in Seawater

Increasing atmospheric CO2 over the next 200 years will cause the pH of ocean waters to decrease further. Many recent studies have examined the effect of decreasing pH on calcifying organisms in ocean waters and on other biological processes (photosynthesis, nitrogen fixation, elemental ratios, and community structure). In this review, we examine how pH will change the organic and inorganic speciation of metals in surface ocean waters, and the effect that it will have on the interactions of metals with marine organisms. We consider both kinetic and equilibrium processes. The decrease in concentration of OH- and CO32- ions can affect the solubility, adsorption, toxicity, and rates of redox processes of metals in seawater. Future studies are needed to examine how pH affects the interactions of metals complexed to organic ligands and with marine organisms

Spectroscopic measurements of the pH in NaCl brines

Spectrophotometric measurements of the pH in natural waters such as seawater have been shown to yield precise results. In this paper, the sulfonephthalein indicator m-cresol purple ( mCP, H 2I) has been used to determine the pH of NaCl brines. The indicator has been calibrated in NaCl solutions from 5 to 45 °C and ionic strengths from 0.03 to 5.5 m. The calibrations were made using TRIS buffers (0.03 m, TRIS/TRIS–HCl) with known dissociation constants pK TRIS in NaCl solutions [Foti C., Rigano C. and Sammartano S. (1999) Analysis of thermodynamic data for complex formation: protonation of THAM and fluoride ion at different temperatures and ionic strength. Ann. Chim. 89, 1–12]. The values of pH were determined from pH = pK m CP + log { ( R - e 1 ) / ( e 2 - Re 3 ) } where R = 578 A/ 434 A, the ratios of the indicator absorbance maximum at 578 and 434 nm, e 1 = 0.00691, e 2 = 2.222 and e 3 = 0.1331 [Clayton T. and Byrne R. H. (1993) Spectrophotometric seawater pH measurements: total hydrogen ion concentration scale calibration of m-cresol purple and at-sea results. Deep-Sea Res. 40, 2115–2129]. Measurements were also made in NaCl solutions with different levels of TRIS (0.01–0.11 m). At low levels of TRIS buffer (<0.03 m), the values of pK m CP increased significantly. This effect can lead to erroneous values of pK m CP at low ionic strengths in estuaries and lakes. The measured values of pK m CP in NaCl as a function of ionic strength ( I/m) and temperature ( T/K) were fitted to the equation ( σ = 0.0072) pK m CP = - 29.095 + 2639.2 / T + 5.0417 ln T - 0.3307 I 0.5 - 186.80 I 0.5 / T - 0.28346 I + 296.44 I / T + 0.12841 I 1.5 - 68.23 I 1.5 / T These results should be useful in determining the pH of NaCl brines in natural waters from 0 to 50 °C

Abstract 4631: Enhancement of prostate cancer diagnosis through distribution analysis of a biomarker for apoptosis within subcellular fractions of prostate biopsy cores

Abstract Introduction: A major problem inherent in prostate cancer (PCa) management is the lack of specificity of the PSA test. Other tests - DRE, PCA-3 plus and standard 12 core ultrasound guided biopsies (TRUS) - also do not always accurately predict a definitive diagnosis. More sensitive and specific tests are needed. Glucose-regulated protein GRP78, an apoptosis marker, is reported to be related to several human cancers. In this study, we evaluated GRP78 as a PCa biomarker using EDGE*TEST™ (E*T), a subcellular fractionation/statistical analysis technology, to determine if it can detect and differentiate PCa from BPH, and if it can predict PCa activity throughout the prostate rather than through individual targeted biopsies. Methods: Twenty four patients with elevated PSA, abnormal DRE and/or elevated PCA-3 plus genetic test had 12 core TRUS biopsies performed by a single urologist. At time of biopsy, additional random two core prostate biopsies (one per lobe) were collected for E*T. The two cores were combined, homogenized and nuclei removed. Post-nuclear supernatants were fractionated, using Edge 200 Separation System, into 4 subcellular fractions, the fractions subjected to western blot analysis using GRP78, and GRP78 distribution ratios analyzed against the number of positive PCa biopsy cores and cores negative for cancer. E*T analyses of patients’ relative distribution profiles were blinded against all clinical and pathology data. Negative Pca biopsy patients were followed up 18 months to compare E*T to traditional screening and biopsy. Preliminary Results: Results of TRUS biopsies showed 8/24 patients had PCa as diagnosed on initial biopsy. Cores per patient ranged from 2-12/12 regions positive for PCa. E*T, with 2 random cores, correlated with 7/8 (87.5%) diagnosed cancers. Of 16 patients initially tested with 0/12 core biopsies positive for PCa, 15/16 (93.8%) were correctly correlated by E*T with non-cancerous disease. Of the initial 15 patients correctly diagnosed by E*T with benign disease and not cancer, only one patient developed cancer on subsequent biopsy. After 18 months follow-up, 7/9 (88.9%) of PCa was detected by E*T based upon initial biopsy. Based on initial biopsy, E*T had a false positive of 1/16 (6.25%) with PCa not detected yet on follow up. E*T had a false negative of 1/16 (6.25%) initially for cancer. Of 16 patients having 0/12 core biopsies PCa positive, 15/16 (93.8%) remained without cancer after 18 months follow-up. E*T was consistent with 14/16 (87.5%) patients, based on initial biopsy, showing high predictive data of benign disease and not cancer. PSA, DRE and PCA-3 were all inconsistent individual or combined indicators. EDGETEST of two random biopsies correlated strongly with PCa activity by evaluating apoptosis and was consistent over 18 month follow up. EDGETEST may be a complementary predictor of PCa over benign disease. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4631.</jats:p

Renal physiology in elderly persons with severe immobility syndrome

The immobility syndrome (IS) is a common condition in the elderly and consists of a reduction in the capacity to perform daily activities because of motor function deterioration. This syndrome leads to characteristic structural and physiological changes in the body, but renal physiology studies have not been conducted on this population. For this reason, we decided to study prospectively changes in renal function in these individuals. We enrolled into this study 17 volunteers over 64 years of age, all of whom lived in the same nursing home. The patients were divided into two groups: nine healthy mobile persons and eight others who suffered from severe IS. Exclusion criteria were the presence of any disease or use of any drug that could induce water and electrolytes alteration. Blood and urine samples were drawn to measure sodium, potassium, creatinine, urea, calcium, phosphorus, magnesium, and uric acid in order to obtain their fractional excretion. Plasma osmolality and vasopressin were also measured. Total body water and lean body mass were obtained by bioelectrical impedance analysis. Statistical analysis was performed applying Student's t-test (P = 0.01) and Pearson's correlation test. A significant difference in body water composition was found between the groups. Thus in the IS group plasma sodium level was slightly lower and total water content was significantly higher than in the mobile subjects: 140 +/- A 5 vs. 143 +/- A 1 mmol/l (P = 0.01); 61 +/- A 8% vs. 50 +/- A 10% (P < 0.001), respectively. Despite these differences, plasma osmolality and vasopressin values were within the normal range in both groups. However, there was a good positive correlation between these two variables in the mobile group only: R 0.9 (mobile) vs. R -0.2 (immobile). We found no significant difference in plasma creatinine or fractional excretion of sodium, potassium, calcium, phosphorus, magnesium, urea, and uric acid between the groups. Total body water content was significantly higher in the elderly who suffered from severe immobility syndrome than in healthy mobile elderly. In contrast with the mobile group, for which there was a good positive correlation between plasma osmolality and plasma vasopressin, for individuals with IS there was no correlation between plasma osmolality and plasma vasopressin