Flow injection assays for NADH and ethanol using photosensitized rose bengal and luminol-copper (II) chemiluminescence system

The on-line photoreaction of rose bengal photosensitized luminol-copper (II) chemiluminescence (CL) system was used for the determination of β-nicotinamide adenine dinucleotide (NADH) and ethanol (EtOH) in pharmaceutical formulations combined with flow injection (FI) technique. NADH can significantly enhance the CL emission of the reaction. For EtOH, alcohol dehydrogenase (ADH) in soluble form was utilized in the presence of nicotinamide adenine dinucleotide (NAD⁺ ) resulting in NADH production. The limit of detection (3σ blank, 𝑛 = 3) of 4.0 × 10^-8 and 2.17 × 10^-5 M, and linear range of 1.3 × 10^-7 -2.5 × 10^-5 M (R² = 0.9998, n = 6) and 0.11-2.17 × 10^-3 M (R² = 0.9996, n = 6) were obtained for NADH and EtOH respectively. The injection rate was 100 h^-1 with relative standard deviation (RSD; n = 3) of 1.5%-4.8% in the range studied for both analytes. The procedure was satisfactorily applied to pharmaceutical formulations with recoveries in the range of 91.6 ± 3.0%-110 ± 2.0% for NADH and 88 ± 3.0%-95.4 ± 4.0% for EtOH. The results obtained were very consistent and did not differ considerably from the reported approaches at 95% confidence limit. The possible mechanism of CL reaction is also explained briefly.

Determination of thiram residues in fresh water using flow injection diperiodatonickelate(IV)-quinine chemiluminescence detection

This study developed a simple flow injection (FI) method based on diperiodatonickelate(IV)-sulfuric acid reaction using chemiluminescence (CL) detection for the determination of thiram (THI) fungicide in fresh water using quinine as the sensitizer. The possible mechanism of the CL reaction was described using UV-Vis. absorption and CL spectra. Experimental variables were optimized by applying a univariate approach, and a linear calibration curve was obtained in the range of 1.0 × 10^-3 -2.0 mg L^-1 (R²  = 0.9994, n = 9) with a limit of detection of 5.0 × 10^-4  mg L^-1 (S/N = 3) and an injection throughput of 200 h^-1 . This approach was successfully applied to determine THI in fresh water by using solid-phase extraction and achieved a good recovery rate of 94%-110% with a relative standard deviation of 1.9%-3.7% (n = 4). The results obtained were compared with the reported FI-CL and high-performance liquid chromatography-ultraviolet methods, and the three methods did not differ significantly at the 95% confidence limit.

Distribution of Pesticides in Different Commonly Grown Vegetables of Cameron Highlands, Pahang, Malaysia

Gas chromatography-electron capture detector (GC-ECD) is used to extract and analyse pesticides in vegetable samples collected from Cameron Highlands, Pahang, Malaysia. The limit of detection (LOD) for all pesticides was in the range of 0.03 to 4.5 ng g-1. Recoveries in cabbage, lettuce, and celery ranged from 61.8%-121%, 60-128% and 60%-114%, respectively. The relative standard deviation (RSD) ranged 0.2-15% in cabbage, 0.5-18% in lettuce and 3-19.8% in celery. Organochlorine pesticides (OCPs) concentrations increased down the valley with dichlorodiphenyldichloroethylene (DDE) having the highest concentration at 233 µg kg-1. Organophosphorus pesticides (OPPs) were found to be dispersed throughout the valley, with the highest concentration of parathion ethyl (133 µg kg-1) whereas the pyrethroid pesticides (PYRs) concentrations were comparatively less. The detection frequency in the wet season was highest (5 < - < 100 µg kg-1) for most pesticides. However, in the dry season the pesticides concentrations were higher, at < 5 µg kg-1. PCA analysis indicated that farmers were using a mixture of pesticides.

The Barts Health NHS Trust COVID-19 cohort: characteristics, outcomes and risk scoring of patients in East London

BACKGROUND: Barts Health National Health Service Trust (BHNHST) serves a diverse population of 2.5 million people in London, UK. We undertook a health services assessment of factors used to evaluate the risk of severe acute respiratory coronavirus 2 (SARS-CoV-2) infection.METHODS: Patients with confirmed polymerase chain reaction (PCR) test results admitted between 1 March and 1 August 2020 were included, alongwith clinician-diagnosed suspected cases. Prognostic factors from the 4C Mortality score and 4C Deterioration scores were extracted from electronic health records and logistic regression was used to quantify the strength of association with 28-day mortality and clinical deterioration using national death registry linkage.RESULTS: Of 2783 patients, 1621 had a confirmed diagnosis, of whom 61% were male and 54% were from Black and Minority Ethnic groups; 26% died within 28 days of admission. Mortality was strongly associated with older age. The 4C mortality score had good stratification of risk with a calibration slope of 1.14 (95% CI 1.01-1.27). It may have under-estimated mortality risk in those with a high respiratory rate or requiring oxygen.CONCLUSION: Patients in this diverse patient cohort had similar mortality associated with prognostic factors to the 4C score derivation sample, but survival might be poorer in those with respiratory failure.

Current trends of Hepatitis C virus genotypes and associated risk factors in hemophilia patients in Pakistan

Hemophilia is a rare bleeding disorder that needs plasma or clotting factor concentrate transfusion. Therefore chances of blood-borne pathogens like HCV transmission increase due to high prevalence in healthy donors. This study was aimed to determine the prevalence of HCV genotypes and associated risk factors in hemophilia patients of Khyber Pakhtunkhwa, Pakistan. Blood samples and data were collected from 672 hemophiliacs after proper consent obtained from each patient. Samples were analyzed for anti-HCV, HCV RNA and HCV genotype/s detection. Of the total, 22.32% (150) were anti-HCV positive, of which HCV RNA was detected in 18.45% (124) individuals. HCV genotype 3a was found with significantly higher prevalence (p<0.05) (19.35%) as compared to 2a (16.13%) and 1a (12.90%). HCV-3b and HCV-4 were found each in 3.22% samples. Dual infection of genotypes was found in 22.58% of individuals and 22.58% HCV RNA positive sampels were not typed. A total of 572 (85.12%) subjects had hemophilia A and 100 (14.88%) had hemophilia B. In hemophiliacs A the most dominant genotype was 3a (19.27%) while in hemophilia B, genotype 1a was prevalent (26.67%). Whole blood and plasma transfusion were observed as the main risk factors of HCV. It is concluded that HCV genotype 3a and 2a are prevalent in hemophilia patients of Khyber Pakhtunkhwa Pakistan and the main risk factor observed was an unscreened whole blood transfusion.

Retraction notice to "Synergistic effects of thymoquinone and curcumin on immune response and anti-viral activity against avian influenza virus (H9N2) in turkeys" [Poult. Sci. 95 (2016) 1513-1520]

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The authors retract the above paper due to: 1) conflict of interest among the authors; and 2) addition of coauthor Dr. Muhammad Younus without his knowledge or permission. The authors apologize for these two grave mistakes.

Flow-injection determination of manganese (II) using surfactant enhanced diperiodatonickelate (IV)-rhodamine 6G chemiluminescence

Chemiluminescence (CL) of the rhodamine 6-G-diperiodatonickelate (IV) (Rh6-G-Ni(IV) complex) in the presence of Brij-35 was examined in an alkaline medium and implemented using flow-injection analysis to analyze Mn(II) in natural waters. Brij-35 was identified as the surfactant of choice that enhanced CL intensity by about 62% of the reaction. The calibration curves were linear in the range 1.7 × 10^-3 - 0.2 (0.9990, n = 7) and 8.0 × 10^-4 - 0.1 μg ml^-1 (0.9990, n = 7) with limits of detection (LODs) (S:N = 3) of 5.0 × 10^-4 and 2.4 × 10^-4 μg ml^-1 without and with using an in-line 8-hydroxyquinoline (8-HQ) resin mini-column, respectively. The sample throughput and relative standard deviation were 200 h^-1 and 1.7-2.2% in the range studied respectively. Mn(II) concentrations in certified reference materials and natural water samples was successfully determined. A brief discussion about the possible CL reaction mechanism is also given. In addition, analysis of V(III), Cr(III) and Fe(II) was also performed without and with using an in-line 8-HQ column and selective elution of each metal ion was achieved by adjusting the pH of the sample carrier stream with aqueous HCl solution.

Surfactant enhanced flow injection chemiluminescence method for vitamin D3 determination in pharmaceutical formulations

A flow injection based chemiluminescence process has been reported for vitamin D₃ determination without using especial chemiluminescence reagent. Vitamin D₃ shows enhancement on the CL intensity of diperiodatocuprate(III) with surfactant (Triton X-100) solution. The calibration curve was found to be linear over the concentration range 0.01-40 mg/L (R² = 0.9997, n = 8) tested. A limit of detection (S/N = 3), limit of quantification (S/N = 10) and sample injection throughput of 2.5 × 10^-3, 8.3 × 10^-3 mg/L and 150 h^-1 respectively were obtained. Various experimental variables were tested to get most suitable response, e.g., the concentrations of reagents, and their flow rates, sample injection volume and photomultiplier tube voltage. The effect of potential interferences was also examined. Vitamin D₃ determination was successfully carried out in pharmaceutical formulations. The recoveries from the formulations were obtained in the range of 96 ± 4-108 ± 2%. The reaction mechanism discussion for diperiodatocuprate(III) complex-Triton X-100-vitamin D₃ was also included.

Fate, distribution, and bioconcentration of pesticides impact on the organic farms of Cameron Highlands, Malaysia

Occurrence and distribution of organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), and pyrethroid pesticides (PYRs) residues in the leafy vegetables were analyzed together with the soil samples using gas chromatography-electron capture detector. Edible tissues of vegetables showed detectable residues of these compounds indicating the influence of the conventional farms and nearby organic farms. In the vegetables, the OCPs concentrations were recorded as nd-133.3 ng/g, OPPs as nd-200 ng/g, and PYRs as nd-33.3 ng/g. In the soil, the OCPs concentrations were recorded as nd-30.6 ng/g, OPPs as nd-26.6 ng/g, and for PYRs as nd-6.7 ng/g. Bioconcentration factor (BCF) was higher for the OPPs (0.3) than the OCPs and PYRs (1.1). The OCPs concentration in the vegetables decreased in the following order: spinach > celery > broccoli > cauliflower > cabbage > lettuce > mustard. For OPPs, the concentration decreased in the following order: cauliflower > spinach > celery > cabbage > broccoli > lettuce > mustard and for PYRs as spinach > celery > lettuce > cabbage > broccoli. Principal component analysis indicates that the sources of these pesticides are not the same, and the pesticide application on the vegetables depends on the type of crop. There is a significant positive correlation between OPPs and the soil (r = 0.65) as compared to OCPs and PYRs (r = 0.1) as the vegetables accumulated OPPs more efficiently than OCPs and PYRs.

Flow Injection-Chemiluminescence Method for Determination of Hyoscine Butylbromide Using Silver(III) as Oxidizing Agent

Diperiodatoargentate(III) (DPA)/silver(III) complex, [Ag(HIO₆)₂]^5-, in sulfuric acid medium has been used to determine hyoscine butylbromide (HBB) by flow injection (FI) coupled with chemiluminescence (CL) detector. A linear standard curve between the CL intensity and concentration range from 0.005 to 20 mg L^-1 was obtained. The determination coefficient (R²), limit of detection (3s × blank), relative standard deviation (RSD) for 0.5 mg L^-1 HBB and analytical throughput were 0.9992 (n = 8), 5 × 10^-4 mg L^-1, 1.5% (n = 10) and 160 injections h^-1, respectively. The developed method was applied for the determination of HBB in pharmaceutical formulations with recoveries from 92 ± 4 to 108 ± 3%. For comparison, a spectrophotometric method was used and the results obtained by both methods were in good agreement at a 95% confidence level. The effect of key chemical and physical variables (reagent concentration, flow rate, sample volume, PMT voltage) and interfering species (pharmaceutical excipients and inorganic ions) on the determination of HBB was examined. The possible CL mechanism of HBB on silver(III) complex in sulfuric acid medium was also discussed in brief.

Estrogen protects the blood-brain barrier from inflammation-induced disruption and increased lymphocyte trafficking

Sex differences have been widely reported in neuroinflammatory disorders, focusing on the contributory role of estrogen. The microvascular endothelium of the brain is a critical component of the blood-brain barrier (BBB) and it is recognized as a major interface for communication between the periphery and the brain. As such, the cerebral capillary endothelium represents an important target for the peripheral estrogen neuroprotective functions, leading us to hypothesize that estrogen can limit BBB breakdown following the onset of peripheral inflammation. Comparison of male and female murine responses to peripheral LPS challenge revealed a short-term inflammation-induced deficit in BBB integrity in males that was not apparent in young females, but was notable in older, reproductively senescent females. Importantly, ovariectomy and hence estrogen loss recapitulated an aged phenotype in young females, which was reversible upon estradiol replacement. Using a well-established model of human cerebrovascular endothelial cells we investigated the effects of estradiol upon key barrier features, namely paracellular permeability, transendothelial electrical resistance, tight junction integrity and lymphocyte transmigration under basal and inflammatory conditions, modeled by treatment with TNFα and IFNγ. In all cases estradiol prevented inflammation-induced defects in barrier function, action mediated in large part through up-regulation of the central coordinator of tight junction integrity, annexin A1. The key role of this protein was then further confirmed in studies of human or murine annexin A1 genetic ablation models. Together, our data provide novel mechanisms for the protective effects of estrogen, and enhance our understanding of the beneficial role it plays in neurovascular/neuroimmune disease.

23-year-old female with dyspnea, hematuria, and seizure progressing to respiratory failure

Takayasu arteritis is a rare chronic inflammatory disease on unknown etiology. We report a 23-year old female who presented with fever, shortness of breath and abdominal pain. Shortly thereafter the patient developed hematuria, hemoptysis and seizure progressing to respiratory failure. She was found to have aortitis and alveolar hemorrhage. We discuss the clinical manifestations and the diagnostic work up of Takayasu arteritis. The patient's response to therapy and a discussion on treatment modalities of the disease are also included in the report.

Determination of nitrate and nitrite in freshwaters using flow-injection with luminol chemiluminescence detection

A simple and sensitive flow-injection (FI) method for the determination of nitrate and nitrite in natural waters, based on luminol chemiluminescence (CL) detection, is reported. Nitrate was reduced online to nitrite via a copperized cadmium (Cu-Cd) column and then reacted with acidic hydrogen peroxide to form peroxynitrous acid. CL emission was observed from the oxidation of luminol in an alkaline medium in the presence of the peroxynitrite anion. The limits of detection (S:N = 3) were 0.02 and 0.01 µg N/L, with sample throughputs of 40 and 90 /h for nitrate and nitrite, respectively. Calibration graphs were linear over the range 0.02-50 and 0.01-50 µg N/L [R2  = 0.9984 (n = 8) and R2  = 0.9965 (n = 7)] for nitrate and nitrite, respectively, with relative standard deviations (RSDs; n = 3) in the range 1.8-4.6%. The key chemical and physical variables (reagent concentrations, buffer pH, flow rates, sample volume, Cu-Cd reductor column length) were optimized and potential interferences investigated. The effect of cations [Ca(II), Mg(II), Co(II), Fe(II) and Cu(II)] was masked online with EDTA. Common anions (PO4(3-) , SO4(2-) and HCO3-) did not interfere at their maximum admissible concentrations in freshwaters. The effect of salinity on the luminol CL reaction with and without nitrate and nitrite (2 and 0.5 µg N/L, respectively) was also investigated. The method was successfully applied to freshwaters and the results obtained were in good agreement with those obtained by an automated segmented flow analyser reference method.

Determination of Nitrite and Nitrate in Freshwaters using Flow Injection Luminol Chemiluminescence Detection

A flow injection method for determination of nitrite and nitrate in freshwaters is described based on luminol-hypochlorite chemiluminescence (CL) system. Nitrate is reduced on-line with a cadmium reduction column to nitrite and its inhibition effect on luminol CL emission was measured. The effects of chemical and physical parameters such as buffer pH and concentration, luminol, sodium hypochlorite and sulfuric acid concentrations, flow rate, and sample volume were investigated. The calibration graphs were linear over the range 0.1-50 µM (R2 = 0.9989 and 0.9984) for nitrite and nitrate respectively with a limit of detection (S/N = 3) of 4.0 × 10-8 M and a sample throughput of 120 samples per hour. The effect of foreign ions was studied and the method was successfully applied to the determination of nitrite and nitrate in water samples. The results obtained were in good agreement with those achieved by a spectrophotometric reference method at the 95% confidence level. Standard addition method was also applied to the freshwater samples and the recovery values were found in the range of 92-109% and 94-105% for nitrite and nitrate respectively.

Enzymatic determination of vitamin A in pharmaceutical formulations with spectrophotometric detection

An enzymatic method for the determination vitamin A (retinol) is reported using soluble and immobilized alcohol dehydrogenase, isolated from rabbit liver. The reaction is based on the oxidation of retinol and simultaneous reduction of NAD(+) to NADH followed by spectrophotometric detection at 340 nm. The calibration graph was linear over the range of 2.0-10 microM with correlation coefficients of 0.9967 and 0.9992 (n=5) for soluble and immobilized alcohol dehydrogenase respectively, with relative standard deviations (n=3) in the range of 0.5-1.2%. The limit of detection was lower than 1.0 microM. The proposed method was applied to determine vitamin A in pharmaceuticals, and the results obtained were in reasonable agreement with the amount labeled. The results were compared using spectrophotometric reference method, and no significant difference was found between the results of the both methods.

Flow-injection method for the determination of iodide/iodine using Ru(bpy)(3)(3+)-NADH chemiluminescence detection

A two-channel flow-injection (FI) method is reported for the determination of iodide and iodine by its enhancement effect on the Ru(bpy)(3)(3+)-NADH chemiluminescence (CL) system. The limit of detection (3 s of blank) was 1.0 x 10(-9) mol/L iodide/iodine, with a sample throughput of 60/h. The calibration graphs over the range 1.0-50 x 10(-8) mol/L gave correlation coefficients of 0.9994 and 0.999 (n = 5) with relative standard deviations (RSD; n = 4) of 1.0-2.5%, respectively. The effects of interfering cations, anions and some organic compounds were also studied. The method was applied to iodized salts and pharmaceutical samples and the results obtained were in good agreement with the value quoted. The CL method developed was compared with spectrophotometric method.

Flow-injection determination of cysteine in pharmaceuticals based on luminol-persulphate chemiluminescence detection

A flow injection (FI) method is reported for the determination of l-cysteine, based on its enhancement on chemiluminescence (CL) emission of luminol oxidized by sodium persulphate in alkaline solution. The calibration graph was linear over the range 1.0 x 10(-9)-5.0 x 10(-7) mol/L (r(2) = 0.9992), with relative standard deviations (RSDs) in the range 1.1-2.3% (n = 4). The limit of detection (3 sigma blank) was 5.0 x 10(-10) mol/L with a sample throughput of 120/h. The method was applied to pharmaceuticals and the results obtained were in reasonable agreement with the amount labelled. The proposed method was also applied to cysteine in synthetic amino acid mixtures. Calibration graphs of N-acetylcysteine and glutathione over the range 1.0-50 x 10(-8) and 0.5-7.5 x 10(-7) mol/L were also established (r(2) = 0.998 and 0.9986) with RSDs in the range 1.0-2.0% (n = 4), and the limits of detection (3 sigma blank) were 5.0 x 10(-9) and 1.0 x 10(-8) mol/L, respectively.

Prevalence of beta-thalassaemia and sickle cell traits in premarital screening in Al-Qassim, Saudi Arabia

To study the prevalence of beta-thalassaemia and sickle cell traits in the Al-Qassim region, Saudi Arabia. The Ministry of Health of Saudi Arabia launched a countrywide programme in February 2004 to allow all Saudis planning marriage to screen their carrier status for beta-thalassaemia and sickle cell traits. This population survey of mandatory premarital screening for beta-thalassaemia and sickle cell heterozygotes provided an opportunity to estimate the prevalence of these traits in the Al-Qassim region. From February 2004 to October 2006 all individuals attending for premarital screening in that region were screened. For each subject, venous blood was taken to determine complete blood count, red cell indices and hemoglobin electrophoresis. Subjects were considered to have beta-thalassaemia trait if mean corpuscular volume was <79 fl, mean corpuscular haemoglobin <27 pg and haemoglobin A2 level >3.5%; and sickle cell trait if sickle cell haemoglobin amounted to 35 to 45% and sickling test was positive. Totally 38,153 individuals were screened during the study period. The prevalence rates of beta-thalassaemia and sickle cell traits were 0.165% (63/38,153) and 0.252% (96/38,153) respectively. Compared with results of previous studies carried out in this region on the same issue, the prevalence of sickle cell heterozygotes seems to be the same but the frequency of beta-thalassaemia carriers is substantially higher. Screening for carriers both of beta-thalassaemia and sickle cell traits is important to prevent at risk marriages through genetic counseling.

Flow-injection determination of thyroxine using immobilized enzyme with tris(2,2'-bipyridyl)ruthenium(III) chemiluminescence detection

A flow-injection method is reported for the determination of thyroxine based on its enhancement effect on the tris(2,2'-bipyridyl)ruthenium(III) chemiluminescence reaction in the presence of NADH using immobilized alcohol dehydrogenase purified from baker yeast. The limit of detection (3 sigma blank) was 5.0 x 10(-8) M with a sample throughput of 80 h(-1). The calibration graph was linear over the range 0.5 - 10 x 10(-7) M (r2= 0.9988) with the relative standard deviation in the range 1.4 - 3.5% (n = 4). The effect of common excipients used in pharmaceutical preparations, some organic compounds and metal ions was studied. The method was applied to pharmaceutical thyroxine tablets, and the obtained results were not significantly different from the amount quoted.

Flow-injection determination of carbaryl and carbofuran based on KMnO4–Na2SO3 chemiluminescence detection

A flow-injection method is described for the determination of carbaryl and carbofuran. It was found that a strong chemiluminescence (CL) signal was generated when these pesticides were mixed with Na(2)SO(3) and KMnO(4) in acidic medium. Under the optimum experimental conditions, the enhanced CL intensity was linear, with the concentrations in the range 0.1-2.0 microg/mL (r(2) = 0.9996 and 0.9993, n = 6) with relative standard deviation (n = 4) in the range 1.0-2.3%. The limits of detection (3sigma blank) were 10 and 50 ng/mL, respectively, with a sample throughput of 180/h. The proposed method was applied to determine carbaryl and carbofuran in freshwaters with satisfactory results. Most metal and non-metal ions and some pesticides, such as carbophenothion and aldicarb, do not interfere with the determination. Dinoseb, diazinon and malathion calibration graphs (in the range 0.2-2.0 microg/mL, r(2) = 0.9966-0.9988, n = 6) were also established with relative standard deviations (n = 4) in the range 1.2-2.0% with limits of detection (3sigma blank) in the range 100-300 ng/mL.

Determination of thyroxine in pharmaceuticals using flow injection with luminol chemiluminescence inhibition detection

A simple flow injection method is reported for the determination of thyroxine, based on its inhibition effect on luminol-iron(II) chemiluminescence in alkaline medium in the presence of molecular oxygen. The detection limits (2s) for d- and l-thyroxine are 0.08 and 0.1 mg/L, respectively, with a sample throughput of 100/h. The calibration data for d- and l-thyroxine over the range 0.2-1.0 mg/L gives correlation coefficients (r(2)) of 0.9915 and 0.984 with relative standard deviations (RSD; n = 4) in the range 1.2-2.8%. The effects of some organic compounds was studied on luminol-iron(II) CL system for thyroxine determination. The method was applied to pharmaceutical thyroxine tablets and the results obtained (in the range 50.5 +/- 2.0-51.6 +/- 1.2 microg l-thyroxine/tablet) were in reasonable agreement with the value quoted.

Determination of iodide using flow injection with acidic potassium permanganate chemiluminescence detection

A simple and rapid flow-injection method is described for the determination of iodide, based on potassium permanganate chemiluminescence detection via oxidation of formaldehyde in aqueous hydrochloric acid. The calibration graph was linear over the range 1.0-12 x 10(-6) mol/L (r2 = 0.9955) with relative standard deviations (n = 4) in the range 1.0-3.5%. The detection limit (3sigma) was 1.0 x 10(-7) mol/L, with sample throughput of 120/h. The effect of interfering cations [Ca(II), Mg(II), Ni(II), Fe(II), Fe(III) and Pb(II)] and anions (Cl-, SO4(2-), PO4(3-), NO3-, NO2-, F- and SO3(2-)) were studied. The method was applied to iodized salt samples and the results obtained in the range 0.03 +/- 0.005 - 0.10 +/- 0.006 mg I/g were in reasonable agreement with the amount labelled. The method was statistically compared with the results obtained by titration; no significant disagreement at 95% confidence was observed.

Systematic review on urine albumin testing for early detection of diabetic complications

OBJECTIVES

To determine whether microalbuminuria is an independent prognostic factor for the development of diabetic complications and whether improved glycaemic or blood pressure control has a greater influence on the development of diabetic complications in those with microalbuminuria than in those with normoalbuminuria.

DATA SOURCES

Electronic databases up until January 2002.

REVIEW METHODS

A protocol for peer review by an external expert panel was prepared that included selection criteria for data extraction and required two independent reviewers to undertake article selection and review. Completeness was assessed using hand-searching of major journals. Random effects meta-analysis was used to obtain combined estimates of relative risk (RR). Funnel plots, trim and fill methods and meta-regression were used to assess publication bias and sources of heterogeneity.

RESULTS

In patients with type 1 or type 2 DM and microalbuminuria there is a RR of all-cause mortality of 1.8 [95% confidence interval (CI) 1.5 to 2.1] and 1.9 (95% CI 1.7 to 2.1) respectively. Similar RRs were found for other mortality end-points, with age of cohort being inversely related to the RR in type 2 DM. In patients with type 1 DM, there is evidence that microalbuminuria or raised albumin excretion rate has only weak, if any, independent prognostic significance for the incidence of retinopathy and no evidence that it predicts progression of retinopathy, although strong evidence exists for the independent prognostic significance of microalbuminuria or raised albumin excretion rate for the development of proliferative retinopathy (crude RR of 4.1, 95% CI 1.8 to 9.4). For type 2 DM, there is no evidence of any independent prognostic significance for the incidence of retinopathy and little, if any, prognostic relationship between microalbuminuria and the progression of retinopathy or development of proliferative retinopathy. In patients with type 1 DM and microalbuminuria there is an RR of developing end-stage renal disease (ESRD) of 4.8 (95% CI 3.0 to 7.5) and a higher RR (7.5, 95% CI 5.4 to 10.5) of developing clinical proteinuria, with a significantly greater fall in glomerular filtration rate (GFR) in patients with microalbuminuria. In patients with type 2 DM, similar RRs were observed: 3.6 (95% CI 1.6 to 8.4) for developing ESRD and 7.5 (95% CI 5.2 to 10.9) for developing clinical proteinuria, with a significantly greater decline in GFR in the microalbuminuria group of 1.7 (95% CI 0.1 to 3.2) ml per minute per year compared with those who were normoalbuminuric. In adults with type 1 or type 2 DM and microalbuminuria at baseline, the numbers progressing to clinical proteinuria (19% and 24%, respectively) and those regressing to normoalbuminuria (26% and 18%, respectively) did not differ significantly. In children with type 1 DM, regression (44%) was significantly more frequent than progression (15%). In patients with type 1 or type 2 DM and microalbuminuria, there is scarce evidence as to whether improved glycaemic control has any effect on the incidence of cardiovascular disease (CVD), the incidence or progression of retinopathy, or the development of renal complications. However, among patients not stratified by albuminuria, improved glycaemic control benefits retinal and renal complications and may benefit CVD. In the effects of angiotensin-converting enzyme (ACE) inhibitors on GFR in normotensive microalbuminuric patients with type 1 DM, there was no evidence of a consistent treatment effect. There is strong evidence from 11 trials in normotensive type 1 patients with microalbuminuria of a beneficial effect of ACE inhibitor treatment on the risk of developing clinical proteinuria and on the risk of regression to normoalbuminuria. Patients with type 2 DM and microalbuminuria, whether hypertensive or not, may obtain additional cardiovascular benefit from an ACE inhibitor and there may be a beneficial effect on the development of retinopathy in normotensive patients irrespective of albuminuria. There is limited evidence that treatment of hypertensive microalbuminuric type 2 diabetic patients with blockers of the renin--angiotensin system is associated with preserved GFR, but also evidence of no differences in GFR in comparisons with other antihypertensive agents. The data on GFR in normotensive cohorts are inconclusive. In normotensive type 2 patients with microalbuminuria there is evidence from three trials (all enalapril) of a reduction in risk of developing clinical proteinuria; in hypertensive patients there is evidence from one placebo-controlled trial (irbesartan) of a reduction in this risk. Intensive compared with moderate blood pressure control did not affect the rate of progression of microalbuminuria to clinical proteinuria in the one available study. There is inconclusive evidence from four trials of any difference in the proportions of hypertensive patients progressing from microalbuminuria to clinical proteinuria when ACE inhibitors are compared with other antihypertensive agents, and in one trial regression was two-fold higher with lisinopril than with nifedipine.

CONCLUSIONS

The most pronounced benefits of glycaemic control identified in this review are on retinal and renal complications in both normoalbuminuric and microalbuminuric patients considered together, with little or no evidence of any greater benefit in those with microalbuminuria. Hence, microalbuminuric status may be a false boundary when considering the benefits of glycaemic control. Classification of a person as normoalbuminuric must not serve to suggest that they will derive less benefit from optimal glycaemic control than a person who is microalbuminuric. All hypertensive patients benefit from blood pressure lowering and there is little evidence of additional benefit in those with microalbuminuria. Antihypertensive therapy with an ACE inhibitor in normotensive patients with microalbuminuria is beneficial. Monitoring microalbuminuria does not have a proven role in modulating antihypertensive therapy while the patient remains hypertensive. Recommendations for microalbuminuria research include: determining rate and predictors of development and factors involved in regression; carrying out economic evaluations of different screening strategies; investigating the effects of screening on patients; standardising screening tests to enable use of common reference ranges; evaluating the effects of lipid-lowering therapy; and using to modulate antihypertensive therapy.

Effect of Model Ligands on Iron Redox Speciation in Natural Waters Using Flow Injection with Luminol Chemiluminescence Detection

The effects of dissolved organic compounds on the determination of nanomolar concentrations of Fe(II) have been compared using two luminol-based flow injection chemiluminescence (FI-CL) methods. One used the direct injection of sample into the luminol reagent stream, and the other incorporated on-line solid-phase extraction of the analyte on an 8-hydroxyquinoline microcolumn. The CL signals from analyses of dissolved iron species (Fe(II) and Fe(III)) with model ligands and organic compounds were examined in high-purity water and seawater. The organic compounds included natural reducing agents (e.g., ascorbic acid), nitrogen sigma-donor/pi-acceptor compounds (e.g., 1,4-dipyridine, protoporphyrin IX), aromatic compounds (e.g., 1,4-dihydroxybenzene), synthetic iron chelators (e.g., EDTA), and natural iron binding compounds (e.g., desferrioxamine B, ferrichrome A). Fe(II) determinations for both luminol FI-CL methods were affected by submicromolar concentrations of redox-active compounds, strong iron binding ligands (i.e., log K(FeL) > 6), and compounds with electron-donating functional groups in both high-purity water and seawater. This was due to reactions between organic molecules and iron species before and during analysis, rather than chemiluminescence caused by the individual organic compounds. In addition, the effects of strong ligands and size speciation on Fe(II) recoveries from seawater following acidification (pH 2) and reduction (100 microM sodium sulfite) were investigated.