Determination of synthetic food colorants in fish products by an HPLC-DAD method.

Reliable methods for quantification of synthetic water-soluble colors in complex food matrices are currently not available. The present work describes the development and validation of an improved protocol for the analysis of synthetic food colorants in complex food matrices presenting high protein and/or fat content. The method developed employs an extraction stage, followed by a subsequent sonification, centrifugation and concentration step. A final clean up via SPE on polyamide cartridges was also employed. The isolated colorants were separated and analyzed by an RP-HPLC/DAD system. High and consistent recoveries (min. 81%) and low RSDs (max. 6%) were achieved for all studied colorants. The issue of high fat content matrices was also addressed showing the need for an additional defatting step in the procedure. Overall, the protocol presented shows high precision and accuracy of detection and can provide the basis for future development of similar methods in other complex food matrices.

Single-shot coherent Rayleigh-Brillouin scattering using a chirped optical lattice.

We present a method for obtaining coherent Rayleigh-Brillouin scattering (CRBS) spectra on timescales of hundreds of nanoseconds using rapidly chirped, pulsed, optical lattices. This enables us to transfer the spectral profile to a temporal profile which can be easily recorded on a single shot of an oscilloscope. These spectra are demonstrated to have sufficient signal-to-noise ratio to study CRBS models over a wide range of gas densities.

Coherent Brillouin scattering.

We measure the spectrum of coherent Brillouin scattering (CBS) in a gas as a function of time and observe for the first time additional spectral sidebands and line shape narrowing of the Brillouin peak. We find that both effects result from the interference of the density modulation induced by the moving dipole force of the pump beams with the acoustic waves induced by their fast thermalization and are predicted by a hydrodynamic-light scattering model. These line shapes differ from both spontaneous and stimulated Brillouin scattering spectra and also from previous coherent Rayleigh-Brillouin measurements.

Correlation of bone mineral density with the histological findings of renal osteodystrophy in patients on hemodialysis.

AIMS: To examine the distribution of bone mineral density (BMD) in different histological groups of renal osteodystrophy. PATIENTS: We prospectively studied 62 patients, 41 men and 21 women, aged 57+/-11.5 years, who had been on hemodialysis for 60+/-55 months. The women had been amenorrheic for 13+/-4 years and 7 patients (11%) had a positive fracture history. METHODS: A bone biopsy was taken after tetracycline labelling and BMD of the lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry (DEXA); serum intact parathyroid hormone (iPTH), bone Gla protein (BGP), phosphorus, calcium and alkaline phosphatase (ALP) were also determined. RESULTS: Histologically, 40 patients showed secondary hyperparathyroidism (sHPT), 6 mixed bone disease, 14 adynamic bone disease (A) and 2 osteomalacia. BMD of the lumbar spine was decreased in 43 patients (69%) and in 9 (14.5%) it was lower than -2 Z score units. BMD of the femoral neck was low in 55 patients (89%) and in 22 (35.5%) it was lower than -2 Z scores. BMD was lower in patients with sHPT than in those with adynamic bone disease (p<0.05) in which it was close to normal. BMD in both these sites correlated inversely with the biochemical markers (serum iPTH, BGP and ALP) and the histomorphometric indices of bone turnover. CONCLUSIONS: Osteopenia is frequent in patients on hemodialysis, especially those with biochemical and histological findings of sHPT.

Kinetic study and analytical applications of micellar catalyzed reactions of 1-fluoro-2,4-dinitrobenzene with inorganic thioanions using a fluoride-selective electrode.

A kinetic study and analytical applications of the CPC micellar catalyzed reactions of 1-fluoro-2,4-dinitrobenzene (FDNB) with inorganic thioanions (sulfide, sulfite and thiosulfafte) using a fluoride-selective electrode is described. Reaction orders (unity for both FDNB and thioanion) and experimental stoichiometric reaction-rate constants were calculated from initial slope measurements (DeltaE/Deltat) at various pH values (4-9). Calibration graphs for quantitative determinations (4.5-45 muM for sulfide, 2.4-75 muM for thiosulfate and 6.6-75 muM for sulfite) are constructed using the initial rate approach. The proposed method has been applied to the determination of sulfide in spiked seawater samples using the multiple standard addition approach with a mean relative error of 5.5%. The application of this micellar catalyzed reaction in the differential kinetic analysis of binary mixtures of sulfide-thiosulfate and sulfite-thiosulfate, using the proportional equations approach at pH 5.5 and 8.0, was unsuccessful due to the interactions of the two analytes, which can be explained using the ion-exchange/pseudophase model of micellar catalysis. However, the use of multiple linear regression approach on a sufficient number of standard binary mixtures can confront this drawback.

Does immunosuppression with prednisolone and azathioprine alter the progression of idiopathic membranous nephropathy?

The role of immunosuppressive drugs in the treatment of idiopathic membranous nephropathy (IMN) remains controversial. The effect of treatment with prednisolone and azathioprine in patients with nephrotic-range proteinuria and biopsy-proven IMN from a single center (Sheffield Kidney Institute, Sheffield, UK) is described. In this retrospective study, 58 patients with IMN and nephrotic-range proteinuria were followed up for 4 years. Thirty-eight patients were treated with prednisolone (1 mg/kg body weight/d) and azathioprine (2 mg/kg body weight/d) orally for a median period of 26 months (range, 6 to 48 months). Twenty patients received no specific treatment for IMN and served as a control group. Clinical, biochemical, and histopathologic features at presentation were similar between the groups. Renal function (RF), measured by serum creatinine (Scr) level, deteriorated in both treated and control groups during the follow-up period. The median initial and final Scr levels (at the end of follow-up) in the treated group were 1.6 and 2. 1 mg/dL, respectively, and in the control group were 1.3 and 1.7 m/dL, respectively (P = not significant). Neither the rate of RF decline (measured by the slope of reciprocal of Scr against time) nor the proportion of patients with deteriorating RF differed significantly between the groups (37%, treated group; 30%, control group). A significant reduction in proteinuria was observed in both groups (P < 0.01, either group). Also, the rate of remission of nephrotic-range proteinuria was not significantly different between groups (55%, treated group; 65%, control group). The only prognostic factor that correlated with RF outcome (expressed by final Scr level) in a given patient was the mean proteinuria during follow-up in either group (r = 0.493; P < 0.01, treated group; r = 0.651; P < 0.01, control group). Adverse effects of immunosuppressive treatment were observed in nine patients (24%). These were serious in four patients (10%) and included squamous cell carcinoma (two patients), bacterial meningitis (one patient), and septicemia (one patient). In conclusion, treatment with prednisolone and azathioprine for patients with IMN did not show significant beneficial effects on the progression of disease. Furthermore, this treatment was associated with frequent and serious adverse effects.

RESEARCH: Evaluating Sustainability of Watershed Resources Management Through Wetland Functional Analysis.

/ Unsustainable agricultural policies and water and soil resource schemes have drained two thirds of Mediterranean wetlands since 1920. An outstanding example is Karla in Greece, a former internationally important wetland that was drained in 1962 causing environmental, social, and water and soil problems. The objective of this study was to assess the functions and values of Karla, at three periods of its history, and to relate them to major events in the management of the water and soil resources of its watershed. Information on wetland and watershed features was collectedfrom historical records and field visits. The results showed that the wetland in its pristine state had performed five functions to a high degree, one (groundwater recharge) to a moderate degree, and one (flood storage) to a low degree. Flood-control works, uncontrolled pumping, etc., in 1936-1961 degraded all functions except microclimate modification while, the bird support function was moderately altered. Drainage works in 1962 left a very small artificially flooded wetland with only four functions performed to an insignificant degree. Value degradation followed function degradation. It was concluded that past resource management has been nonintegrated. No consideration was given to the multiple functions and values of Karla. Previous restoration proposals involved the reinstatement of one or two functions only. The appropriate restoration scheme for Karla must be multiobjective and based on the integrated resource management of its own and the neighboring watersheds.KEY WORDS: Soil and water resources; Sustainability; Watershed management; Wetland functional analysis; Karla wetlandhttp://link.springer-ny.com/link/service/journals/00267/bibs/24n2p193.html

Biochemical markers for non-invasive diagnosis of hyperparathyroid bone disease and adynamic bone in patients on haemodialysis.

UNLABELLED: The diagnostic and predictive value of serum intact parathyroid hormone (iPTH) and osteocalcin (bone Gla protein, BGP), alone or in combination, have been examined in only a small number of haemodialysis patients. METHODS: We studied prospectively 114 patients (46 women, 68 men; mean age 52 +/- 12 years) on regular haemodialysis for a mean of 55 (6-185) months. All patients underwent labelled transiliac bone biopsy, and serum levels of iPTH, BGP and alkaline phosphatase were determined. RESULTS: Seventy-one patients (62%) showed histological findings of hyperparathyroid bone disease, 24 (21%) mixed bone disease, six (5.5%) osteomalacia and 13 (11.5%) adynamic bone. Bone aluminium deposition over more than 25% of the trabecular bone interface was found in 66 patients (58%). Serum iPTH and BGP correlated with the majority of histomorphometric indices of bone formation, mineralization and resorption (r > 0.5, P < 0.01). iPTH levels > or = 200 pg/ml and BGP > or = 50 ng/ml were found to be indicative of hyperparathyroid bone disease, whilst iPTH levels < 65 pg/ml and BGP < 20 ng/ml were indicative of adynamic bone. However, the positive predictive value of these indices was limited (less than 80%), although their negative predictive value, especially when used in combination, was good (more than 90%) and the exclusion of hyperparathyroid bone disease and adynamic bone was possible. The diagnostic and predictive value of these bone markers were improved when patients with bone aluminium deposition were excluded. CONCLUSIONS: Diagnosis of hyperparathyroid bone disease and adynamic bone is difficult on the basis of iPTH and BGP, especially when bone aluminium deposition is prevalent. However, using these bone markers, preferably in combination, the exclusion of these lesions is feasible.

Physicochemical studies of the cetyltrimethylammonium bromide micellar system using a bromide selective electrode.

The use of the bromide selective electrode in physicochemical studies of the cationic micellar system of cetyltrimethylammonium bromide (CTAB) is described. Potentiometric methods and appropriate equations have been developed and used to determine the critical micellar concentration, the ionization degree, and the apparent ion-exchange constants of various anions (fluoride, chloride, hydroxide, acetate, nitrate, sulfate and borate). The interaction of the cationic micelles of CTAB with various species [the lipophilic reagent 1-fluoro-2,4-dinitrobenzene, the anionic succinate and the cationic tris-(hydroxymethyl)-aminomethane] was monitored through the measurement of the changes in the concentration of the free bromide counterions.

Micellar acid-base potentiometric titrations of weak acidic and/or insoluble drugs.

The effect of various surfactants [the cationics cetyl trimethyl ammonium bromide (CTAB) and cetyl pyridinium chloride (CPC), the anionic sodium dodecyl sulphate (SDS), and the nonionic polysorbate 80 (Tween 80)] on the solubility and ionization constant of some sparingly soluble weak acids of pharmaceutical interest was studied. Benzoic acid (and its 3-methyl-, 3-nitro-, and 4-tert-butyl-derivatives), acetylsalicylic acid, naproxen and iopanoic acid were chosen as model examples. Precise and accurate acid-base titrations in micellar systems were made feasible using a microcomputer-controlled titrator. The response curve, response time and potential drift of the glass electrode in the micellar systems were examined. The cationics CTAB and CPC were found to increase considerably the ionization constant of the weak acids (delta pKa ranged from -0.21 to -3.57), while the anionic SDS showed negligible effect and the nonionic Tween 80 generally decreased the ionization constants. The solubility of the acids in aqueous micellar and acidified micellar solutions was studied spectrophotometrically and it was found increased in all cases. Acetylsalicylic acid, naproxen, benzoic acid and iopanoic acid could be easily determined in raw material and some of them in pharmaceutical preparations by direct titration in CTAB-micellar system instead of using the traditional non-aqueous or back titrimetry. Precisions of 0.3-4.3% RSD and good correlation with the official tedious methods were obtained. The interference study of some excipients showed that a preliminary test should be carried out before the assay of formulations.

Wave of Middle East migration raises questions of policy in many countries.

PIP: Since 1973 the increase in revenues from petroleum has resulted in a substantial migration of workers to the oil exporting countries of the Middle East. Discussion focuses on the policies being used to minimize the costs and maximize the advantages of emigration, including description and evaluation of measures and proposals for further action. No action seems to have been taken to regulate the present wave of Middle Eastern emigration, probably because in its initial stages it proved an unmixed blessing for the labor exporting countries. Steps should have been taken to protect the emigrants. Their living conditions are unsatisfactory in some host countries, and frequently they are exploited by the unscrupulous middlemen who arranged their employment and wages. No effective international agreements, multilateral or bilateral, have been concluded to deal with these problems. A policy response is required as labor shortages emerge in the later phases of emigration, especially as the balance of payments situation improves and reserves rise. An appropriate strategy should combine both supply and demand management measures. It should avoid overambitious antiinflationary objectives. For the majority of the labor exporting countries discussed here, foreign exchange earnings from migrants have reached sizable amounts, exceeding, for example, $1 billion in Egypt, India, Pakistan, and the Yemen Arab Republic. Countries are maximizing those receipts by resorting to compulsion and surrender requirements. Emigrants should be coaxed and not compelled to remit currently a high proportion of savings and to invest a low percentage in the country where they work or in 3rd countries. Remittances by workers during the period of their stay in foreign countries are made for family maintenance and for investment. The most effective way to satisfy emigrants that they will be able to reexport their assets is to remove all restrictions on payments. Going beyond general policies to create a favorable investment climate, almost all labor exporting countries are providing facilities and incentives for specific transactions of interest to emigrants. Policies which create a favorable investment climate and facilitate the construction of housing can be helpful in attracting emigrants back to their country of origin.^ieng