A nanocomposite/crude extract enzyme-based xanthine biosensor

A novel amperometric biosensor for xanthine was developed based on covalent immobilization of crude xanthine oxidase (XOD) extracted from bovine milk onto a hybrid nanocomposite film via glutaraldehyde. Toward the preparation of the film, a stable colloids solution of core-shell Fe3O4/polyaniline nanoparticles (PANI/Fe3O4 NPs) was dispersed in solution containing chitosan (CHT) and H2PtCl6 and electrodeposited over the surface of a carbon paste electrode (CPE) in one step. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectrophotometry, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used for characterization of the electrode surface. The developed biosensor (XOD/CHT/Pt NPs/PANI/Fe3O4/CPE) was employed for determination of xanthine based on amperometric detection of hydrogen peroxide (H2O2) reduction at -0.35V (vs. Ag/AgCl). The biosensor exhibited a fast response time to xanthine within 8s and a linear working concentration range from 0.2 to 36.0μM (R(2)=0.997) with a detection limit of 0.1μM (signal/noise [S/N]=3). The sensitivity of the biosensor was 13.58μAμM(-1)cm(-2). The apparent Michaelis-Menten (Km) value for xanthine was found to be 4.7μM. The fabricated biosensor was successfully applied for measurement of fish and chicken meat freshness, which was in agreement with the standard method at the 95% confidence level.

Synchronization of delayed coupled neurons in presence of inhomogeneity

In principle, two directly coupled limit cycle oscillators can overcome mismatch in intrinsic rates and match their frequencies, but zero phase lag synchronization is just achievable in the limit of zero mismatch, i.e., with identical oscillators. Delay in communication, on the other hand, can exert phase shift in the activity of the coupled oscillators. In this study, we address the question of how phase locked, and in particular zero phase lag synchronization, can be achieved for a heterogeneous system of two delayed coupled neurons. We have analytically studied the possibility of inphase synchronization and near inphase synchronization when the neurons are not identical or the connections are not exactly symmetric. We have shown that while any single source of inhomogeneity can violate isochronous synchrony, multiple sources of inhomogeneity can compensate for each other and maintain synchrony. Numeric studies on biologically plausible models also support the analytic results.

Preconcentration and speciation of trace amounts of chromium in saline samples using temperature-controlled microextraction based on ionic liquid as extraction solvent and determination by electrothermal atomic absorption spectrometry

A sensitive and selective method for the preconcentration and speciation of sub ng L(-1) levels of chromium species in aqueous solutions with high salt contents is described. The developed method is based on temperature-controlled microextraction of chromium species using the 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM][PF(6)]) ionic liquid as an extractant followed by electrothermal atomic absorption spectrometry (ETAAS) determination. The extraction of chromium species from aqueous solution into the fine droplets of [HMIM][PF(6)] was performed with ammonium pyrrolidine dithiocarbamate (APDC) as the chelating agent. Some predominant factors affecting the preconcentration and speciation of both Cr(III) and Cr(VI) species were evaluated and optimized. Under the optimum conditions, the calibration graphs were linear over the concentration ranges from 50 to 200 ng L(-1) for Cr(III) and from 25 to 150 ng L(-1) for Cr(VI). The limits of detection (LOD) of the developed method were 5.40 ng L(-1) and 2.45 ng L(-1) for Cr(III) and Cr(VI) ions, respectively. The enrichment factor for chromium species was found to be 42. The relative standard deviations for six replicate determinations of 100 ng L(-1) of either Cr(VI) or Cr(III) were 4.24% and 3.05%, respectively. The developed method was successfully applied to the speciation and determination of chromium species in water and urine samples.

Surface modified magnetic Fe3O4 nanoparticles as a selective sorbent for solid phase extraction of uranyl ions from water samples

In this study, silica-coated magnetic nanoparticles modified with quercetin were synthesized by a sol-gel method. These magnetic nanoparticles were assessed as a new solid phase sorbent for extraction of uranyl ions from aqueous solutions. The crystal and chemical structures and magnetic property of the new sorbent were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectrophotometer (FT-IR), and vibration sample magnetometer (VSM). The experimental parameters affecting the extraction efficiency of uranyl ions from aqueous solutions using the synthesized sorbent were optimized by means of the response surface methodology. The adsorption equilibrium of uranyl ions onto the sorbent was explained by Langmuir isotherm and maximum monolayer adsorption capacity was found 12.33mg/g. The synthesized sorbent was applied to extraction of uranyl ions from different water samples.

Early detection of immunization: a study based on an animal model using 1H nuclear magnetic resonance spectroscopy

Vaccines require a period of at least three months for clinical trials, hence a method that can identify elicitation of immune response a few days after the first dose is a necessity. Evolutionary variable selections are modeling approaches for proper manipulation of available data which were used to set up an animal model for classification of time dependent 1HNMR metabolomic profiles and pattern recognition of fluctuations of metabolites in two groups of male rabbits. One group of rabbits was immunized with human red blood cells and the other used as control. Blood was obtained every 48 h from each rabbit for a period of six weeks and the serum monitored for antibodies and metabolites by 1HNMR spectra. Evaluation of data was carried out using orthogonal signal correction followed by principal component analysis and partial least square. A neural network was also set up to predict immunization profiles. A distinct separation in patterns of significant metabolites was obtained between the two groups, just a few days after the first and the second dose. These metabolites were used as targets of neural networks where each sample was used as test, validation and training and their quantitative influence predicted by regression. This model could be used for prediction of immunization in rabbits a few days after the first dose with 96% accuracy. Similar animals and human vaccine trials would assist greatly in reaching early conclusions in advance of the usual two month immunization schedule; resulting in an appreciable saving of cost and time.

Evaluation of serum levels of essential trace elements in patients with pulmonary tuberculosis before and after treatment by age and gender

The purpose of this study was to evaluate the levels of Zinc, Copper, Iron and Copper/Zinc ratio in the serum of adult patients with pulmonary tuberculosis in Iran. Serum levels of Zinc and Copper were determined by flame atomic absorption spectrophotometer and scrum iron concentration was measured by using an Auto Analyzer. The study group consisted of 50 pulmonary tuberculosis patients before treatment and after 6 months of anti-tubercular therapy. Levels of scrum Zn (p < 0.001) and Fe (p < 0.001) in TB patients were significantly increased after 6 months of anti-tubercular therapy. However, serum Cu concentration (p < 0.01) and Cu/Zn ratio (p < 0.05) were decreased after 6 months of anti-tubercular therapy. Some studies indicated a strong association of Zn, Cu, Fe and the Cu/Zn ratio with TB. In this study, we found remarkable change in Cu/Zn ratio. Some researchers mentioned that serum Cu/Zn ratio could be used as an important laboratory marker for diagnosis and treatment of tuberculosis. They also mentioned that trace element levels must be closely monitored during the process of disease.

Cessation of VEGF-targeted therapy in patients with metastatic renal cell carcinoma (mRCC): Feasibility and clinical outcome

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Background: Standard practice in the treatment (tx) of mRCC with VEGF targeted agents is continuous tx until progression of disease (PD) or unacceptable toxicity. Chronic mild to moderate toxicity and risk of long-term toxicity ensue for a subset of pts. It is hypothesized that a subset of pts with an initial response to tx can maintain disease control off all tx for a period of time.

Methods: A retrospective study of mRCC pts who initiated VEGF-targeted tx between January 2004 and November 2009 was conducted. Pts had achieved disease control on tx, then were taken off all tx. Pt, disease and tx characteristics were recorded. Progression free survival (PFS) was measured as the time from discontinuation of tx to RECIST PD.

Results: A total of 30 pts were identified. All pts had prior nephrectomy and had clear cell histology, and 9 patients had prior immunotherapy. At the time tx was stopped 16 pts were receiving sunitinib, 7 pts were receiving sorafenib (2 in combination with AMG 386), and 7 pts were receiving bevacizumab (6 in combination with temsirolimus, 1 with IFN-alpha). Six pts had achieved CR, 19 PR and 5 SD by RECIST. Using Heng's prognostic risk group criteria, 14 pts had favorable, 14 had intermediate, and 2 had poor risk disease prior to initiation of VEGF-targeted tx. Therapy was held for severe adverse events (5pts; 2 MIs, 3 CVAs), toxicity (16 pts; 4 diarrhea, 3 skin, 3 proteinuria, 2 cardiac, 1 fatigue, 1 stomatitis, 1 pneumonitis, 1 nausea), cost (1 pt; high co-pay), pt choice (6 pts) and interventions (2 pts; 1 angioplasty and 1 kidney stone). Median follow up is 29 months (range 11– 82). Median duration of tx prior to discontinuation was 14.6 months (range 3–79). Thirteen pts (43%) had PD off tx (lymph nodes (6), lungs (8; 3 with new lesions), bones (1), brain (2; 1 with new lesions)) with a median PFS of 10 months (range 3–27). After PD, 4 pts were offered sunitinib, 1 pazopanib, 1 everolimus, 1 local RF tx, and 6 continued expectant management. After a median follow-up to date of 7.5 months (2–28), 17 pts (57%) still did not have RECIST PD.

Conclusions: Select mRCC pts with disease control on VEGF-targeted tx can be safely observed off all tx. Further prospective investigation is needed to define the risks and benefits of this approach.

[Table: see text]

Early experiences of abuse and current depressive disorders in Iranian women

Early experience of abuse may be viewed as a risk factor for mental disorders in women later in life. This case-control study in Isfahan screened 709 women aged 20-45 years using the Beck Depression Inventory and structured clinical interviews for Diagnostic Statistical Manual-IV criteria. Lifetime history of abuse was determined using a standard questionnaire. Among the women 35.1% had experienced fear of or actual abuse (physical, sexual or both) in childhood or adolescence. The risk of having major depression in adult life was significantly higher in women who experienced abuse in childhood and adolescence (OR 4.3), severe degrees of abuse (OR 3.9) or multiple forms of abuse (OR 3.8).

Chemical composition, in vitro anti-microbial, antifungal and antioxidant activities of the essential oil and methanolic extract of Hymenocrater longiflorus Benth., of Iran

In this study we identified the chemical composition, anti-microbial and antioxidant effects of essential oil and methanolic extract of Hymenocrater longiflorus Benth. Totally 87 volatile compounds from the essential oil in H. longiflorus, were identified by gas chromatography-mass spectrometry (GC-MS). These compounds are mainly monoterpene hydrocarbons, sesquiterpene hydrocarbons, oxygenated monoterpenes and oxygenated sesquiterpenoids compounds. The anti-microbial and antifungal activity of plants extracts against several pathogenic microorganisms was studied by disc diffusion and minimum inhibitory concentration procedures. The results revealed that the essential oil and polar sub-fraction are effective mostly against Staphylococcus aureus, Aspergillus niger and Candida albicans. The antioxidant activity was also determined by 1,1'-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, beta-carotene linoleic acid assay and reducing power. In addition the total phenol of essential oil (54.6+/-1.2), polar sub-fraction (50.0+/-1.4) and non-polar sub-fraction (64.7+/-2.0) were determined.

Gastro-oesophageal reflux symptoms and the risks of oesophageal cancer: are the effects modified by smoking, NSAIDs or acid suppressants?

OBJECTIVE

To measure the extent to which risks of oesophageal cancers associated with gastro-oesophageal reflux (GOR) are modified by common factors including smoking, non-steroidal anti-inflammatory drugs (NSAIDs) and acid suppressant medications.

DESIGN AND SETTING

Population-based case-control study.

PARTICIPANTS

Cases were patients with oesophageal (OAC; n = 365) or gastro-oesophageal junction (GOJAC; n = 426) adenocarcinomas, or squamous cell carcinomas (OSCC; n = 303). Controls were sampled from a population register (n = 1580).

MAIN OUTCOME MEASURE

Odds ratio and 95% confidence interval.

RESULTS

Frequent (at least weekly) symptoms of GOR were associated with significant 6.4-fold, 4.6-fold and 2.2-fold increased risks of OAC, GOJAC and OSCC, respectively. Under models examining effects of combined exposure, patients with frequent GOR symptoms who were also heavy smokers had markedly higher OAC risks (OR = 12.3, 95% CI 6.3 to 24.0) than those with frequent GOR who did not smoke (OR = 6.8, 95% CI 3.6 to 12.9). Similar patterns were observed for GOJAC and OSCC. Among people with frequent GOR symptoms, regular use of aspirin/NSAIDs was associated with almost two-thirds lower OAC risks (OR = 4.8, 95% CI 2.5 to 9.2) than non-users (13.9, 95% CI 6.5 to 30.0). In contrast, among those with frequent GOR symptoms, users of acid suppressants had similar OAC risks (OR 7.8, 95% CI 5.2 to 11.8) to non-users (OR 5.3, 95% CI 3.2 to 9.0).

CONCLUSIONS

People experiencing frequent GOR symptoms have markedly increased risks of OAC and GOJAC, and this effect may be greater amongst smokers. Use of aspirin and NSAIDs, but not acid suppressants, significantly reduced the risks of oesophageal cancers associated with GOR.

Evaluation of serum levels of zinc, copper, iron, and zinc/copper ratio in cutaneous leishmaniasis

BACKGROUND

The purpose of this study was to evaluate the levels of zinc (Zn), copper (Cu), iron (Fe) and zinc/ copper ratio in the serum of patients with cutaneous leishmaniasis in Qom Province, center of Iran.

METHODS

Serum levels of zinc and copper were determined by flame atomic absorption spectrophotometer and serum iron concentration was measured by using an Auto Analyzer. The study group consisted of 60 patients with cutaneous leishmaniasis and the control group of 100 healthy volunteers from the same area who were not exposed to cutaneous leishmaniasis.

RESULT

There were no statistically significant differences in age and body mass index between the two groups. Serum Zn (P< 0.001) and Fe (P< 0.05) levels were lower in patients with cutaneous leishmaniasis than the control group. We also found serum Cu concentration (P< 0.05) in the patient group was significantly higher than that of the control group. However, zinc/ copper ratio (P< 0.001) was lower in patients with cutaneous leishmaniasis than in the control group.

CONCLUSION

Our data indicated that Zn/Cu ratio was significantly lower in patients with CL as compared to the controls. Earlier reports suggest that, this ratio imbalance could be a useful marker for immune dysfunction in leishmaniasis. There was also strong association of Zn, Cu and Fe with CL. It suggests the use of blood zinc, copper, iron concentration and the copper/zinc ratio (Zn/Cu), as a means for estimating the prognosis of CL.

Solid phase extraction using silica gel modified with murexide for preconcentration of uranium (VI) ions from water samples

Murexide was chemically bonded to silica gel surface immobilized 3-aminopropyl trimethoxysilane (APMS) to produce the new sorbent. A solid phase extraction method using the new sorbent has been developed to separate and concentrate trace amount of uranium (VI) from aqueous samples for the measurement by spectrophotometry method using Arsenazo III reagent. The influences of some analytical parameters on the quantitative recoveries of the analyte were investigated both in batch and column methods. Quantitative recovery of U(VI) was achieved by stripping with 0.1 mol L(-1) HCl. The maximum sorption capacity of the modified silica gel was 1.13 mmol g(-1) U(VI). A high preconcentration factor value of 400 with a lower limit of detection of 1 microg L(-1) was obtained for U(VI). The practical applicability of the developed sorbent was examined using synthetic and real samples such as sea/ground water samples.

Combined effects of obesity, acid reflux and smoking on the risk of adenocarcinomas of the oesophagus

OBJECTIVE

To measure the relative risks of adenocarcinomas of the oesophagus and gastro-oesophageal junction associated with measures of obesity, and their interactions with age, sex, gastro-oesophageal reflux symptoms and smoking.

DESIGN AND SETTING

Population-based case-control study in Australia.

PATIENTS

Patients with adenocarcinomas of the oesophagus (n = 367) or gastro-oesophageal junction (n = 426) were compared with control participants (n = 1580) sampled from a population register.

MAIN OUTCOME MEASURE

Relative risk of adenocarcinoma of the oesophagus or gastro-oesophageal junction.

RESULTS

Risks of oesophageal adenocarcinoma increased monotonically with body mass index (BMI) (p(trend) <0.001). Highest risks were seen for BMI >or=40 kg/m2 (odds ratio (OR) = 6.1, 95% CI 2.7 to 13.6) compared with "healthy" BMI (18.5-24.9 kg/m2). Adjustment for gastro-oesophageal reflux and other factors modestly attenuated risks. Risks associated with obesity were substantially higher among men (OR = 2.6, 95% CI 1.8 to 3.9) than women (OR = 1.4, 95% CI 0.5 to 3.5), and among those aged <50 years (OR = 7.5, 95% CI 1.7 to 33.0) than those aged >or=50 years (OR = 2.2, 95% CI 1.5 to 3.1). Obese people with frequent symptoms of gastro-oesophageal reflux had significantly higher risks (OR = 16.5, 95% CI 8.9 to 30.6) than people with obesity but no reflux (OR = 2.2, 95% CI 1.1 to 4.3) or reflux but no obesity (OR = 5.6, 95% 2.8 to 11.3), consistent with a synergistic interaction between these factors. Similar associations, but of smaller magnitude, were seen for gastro-oesophageal junction adenocarcinomas.

CONCLUSIONS

Obesity increases the risk of oesophageal adenocarcinoma independently of other factors, particularly among men. From a clinical perspective, these data suggest that patients with obesity and frequent symptoms of gastro-oesophageal reflux are at especially increased risk of adenocarcinoma.

Copper (II) ion selective liquid membrane electrode based on new Schiff base carrier

Cu2+ selective PVC membrane electrode based on new Schiff base 2, 2'-[1,9 nonanediyl bis (nitriloethylidyne)]-bis-(1-naphthol) as a selective carrier was constructed. The electrode exhibited a linear potential response within the activity range of 1.0 x 10(-6) - 5.0 x 10(-3) moll(-1) with a Nernstian slope of 29 +/- 1 mV decade(-1) of Cu2+ activity and a limit of detection 8.0 x 10(-7) mol l(-1). The response time of the electrode was fast, 10 s, and stable potentials were obtained within the pH range of 3.5- 6.5. The potentiometric selectivity coefficients were evaluated using two solution method and revealed no important interferences except for Ag+ ion. The proposed electrode was applied as an indicator electrode to potentiometric titration of Cu2+ ions and determination of Cu2+ content in real samples such as black tea leaves and multivitamin capsule.

Spectrophotometric Determination of Rifampicin through Chelate Formation and Charge Transfer Complexation in Pharmaceutical Preparation and Biological Fluids

Two simple and accurate spectrophotometric methods for determination of Rifampicin (RIF) are described. The first method is based on charge transfer (CT) complex formation of the drug with three pi-electron acceptors either 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 7,7,7,8-Tetracyanoquinodimethane (TCNQ) or 2,3,5,6-Tetrachloro-1,4-benzoquinone (p-chloranil) in acetonitrile. The method is followed spectrophotometrically by measuring the maximum absorbance at 584 nm, 761 nm (680 nm) or 560 nm for DDQ, TCNQ and p-chloranil, respectively. Under the optimized experimental conditions, the calibration curves showed a linear relationship over the concentration ranges of 5-140 microg/ml, 2-45 microg/ml (5-120 microg/ml) and 15-200 microg/ml, respectively. The second method is based on the reaction of RIF with iron(III) forming a water insoluble violet complex which is extracted into chloroform. The method determines RIF in concentration range of 10-240 microg/ml at 540 nm. The proposed methods applied to determination of RIF in capsule, human serum and urine samples with good accuracy and precision. The results were compared statistically with the official method and showed no significant different between the methods compared in terms of accuracy and precision.

Selective transport of copper(II) ions across a liquid membrane mediated by Piroxicam

Piroxicam was found to be a highly selective carrier for uphill transport of Cu2+ ions through a chloroform liquid membrane. The transport occurs via a counterflow of protons from the receiving phase to the source phase. The effects of several parameters on the transport of Cu2+ ions, such as the carrier concentration, pH of the source phase, composition of the receiving phase, and duration are described. A high transport efficiency (98+/-2%) was provided by the carrier for Cu2+ ions in a receiving phase of 0.01 mol l(-1) sulfuric acid after 4 h. Different metal ion transport experiments showed that Cu2+ ions were selectively transported over other ions, such as Co2+, Ni2+, Cd2+, Pb2+, Zn2+, UO2(2+) and ZrO2(2+) . In the presence of fluoride ions (used as a suitable masking agent in the source phase), the interfering effects of UO2(2+) and ZrO2(2+) ions were eliminated. The applicability of the method was tested on a real sample, and the results obtained show that it is potentially useful for solvent extraction of copper.

Prevention and treatment of postpartum hypertension

BACKGROUND

Postpartum blood pressure (BP) is highest three to six days after birth when most women have been discharged home. A significant rise in BP may be dangerous (e.g., lead to stroke), but there is little information about how to prevent or treat postpartum hypertension.

OBJECTIVES

To assess the relative benefits and risks of interventions to: (1) prevent postpartum hypertension, by assessing whether 'routine' postpartum administration of oral antihypertensive therapy is better than placebo/no treatment; and(2) treat postpartum hypertension, by assessing whether (i) oral antihypertensive therapy is better than placebo/no therapy for mild-moderate postpartum hypertension; and (ii) one antihypertensive agent offers advantages over another for mild-moderate or severe postpartum hypertension.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register (March 2004), MEDLINE (1966 to May 2003), EMBASE (1980 to January 2003), bibliographies of retrieved papers and personal files.

SELECTION CRITERIA

For women with antenatal hypertension, trials comparing a medical intervention with placebo/no therapy. For women with postpartum hypertension, trials comparing one antihypertensive with either another or placebo/no therapy.

DATA COLLECTION AND ANALYSIS

We extracted the data independently and were not blinded to trial characteristics or outcomes. We contacted authors for missing data when possible.

MAIN RESULTS

Six trials are included.

PREVENTION

Three trials (315 women; six comparisons) compared furosemide or nifedipine capsules with placebo/no therapy. There are insufficient data for conclusions about possible benefits and risks of these management strategies. Most outcomes included data from only one trial. No trial reported severe maternal hypertension or breastfeeding.

TREATMENT

In two trials (106 women; three comparisons), oral timolol or hydralazine were compared with oral methyldopa for treatment of mild to moderate postpartum hypertension. In one trial (38 women; one comparison), oral hydralazine plus sublingual nifedipine were compared with sublingual nifedipine for treatment of severe postpartum hypertension. The need for additional antihypertensive therapy did not differ between groups (relative risk 4.24, 95% confidence interval 0.96 to 18.84; three trials, N = 144 women), but three antihypertensive drugs were studied. All were well tolerated.

AUTHORS' CONCLUSIONS

There are no reliable data to guide management of women who are hypertensive postpartum or at increased risk of becoming so. If a clinician feels that hypertension is severe enough to treat, the agent used should be based on his/her familiarity with the drug. Future studies of prevention or treatment of postpartum hypertension should include information about use of postpartum analgesics and outcomes of severe maternal hypertension, breastfeeding, hospital length of stay, and maternal satisfaction with care.

Molecularly imprinted solid-phase extraction for the screening of antihyperglycemic biguanides

A new molecularly imprinted polymer (MIP) was specifically synthesized as a smart material for the recognition of metformin hydrochloride in solid-phase extraction. Particles of this MIP were packed into a stainless-steel tubing (50 mm x 0.8 mm i.d.) equipped with an exit frit. This micro-column was employed in the development of a molecularly imprinted solid-phase extraction (MISPE) method for metformin determination. The MISPE instrumentation consisted of a micrometer pump, an injector valve equipped with a 20-microl sample loop, a UV detector, and an integrator. With CH3CN as the mobile phase flowing at 0.5 ml/min, 95 +/- 2% binding could be achieved for 1200 ng of metformin from one injection of a phosphate-buffered sample solution (pH 2.5). Methanol + 3% trifluoroacetic acid was good for quantitative pulsed elution (PE) of the bound metformin. The MISPE-PE method, with UV detection at 240 nm, afforded a detection limit of 16 ng (or 0.8 microg/ml) for metformin. However, the micro-column interacted indiscriminately with phenformin with a 49 +/- 2% binding. A systematic investigation of binding selectivity was conducted with respect to sample composition (including the solvent, matrix, pH, buffer and surfactant effects). An intermediate step of differential pulsed elution used acetonitrile with 5% picric acid to remove phenformin and other structural analogues. A final pulsed elution of metformin for direct UV detection was achieved using 3% trifluoroacetic acid in methanol.

Safety of plasmin in the setting of concomitant aspirin and heparin administration in an animal model of bleeding

Plasmin is a direct thrombolytic which has been shown to have a strikingly favorable benefit to risk profile in comparison with plasminogen activators, notably tissue plasminogen activator (t-PA). As heparin is known to increase the risk of hemorrhage when co-administered with a plasminogen activator, we asked whether adjunct antithrombotic agents such as aspirin and heparin would affect the safety of plasmin. Three groups of rabbits were administered plasmin at a dose (4 mg kg-1) designed to induce significant decreases in antiplasmin, fibrinogen and factor (F)VIII, to about 25, 40 and 40%, respectively, of baseline values, but not cause prolongation of the ear puncture bleeding time. In a blinded and randomized trial, the results show that an intravenous aspirin bolus plus heparin administered as a bolus followed by a maintenance continuous infusion did not significantly prolong the bleeding time during plasmin infusion. These data indicate that in the rabbit, concomitant use of aspirin plus heparin does not affect the safety of a therapeutic dose of plasmin.

Solid-phase extraction-spectrophotometric determination of uranium(VI) in natural waters

A method for the extraction and determination of uranyl ion in natural waters using octadecyl bonded silica membrane disks modified with piroxicam and spectrophotometry with arsenazo(III) is proposed. The perconcentration step was studied with regard to experimental parameters such as amount of extractant, type and amount of eluent, pH, flow rates and tolerance limit of diverse ions on the recovery of uranyl ion. The limit of detection of the proposed method is 0.4 micro g L(-1) of uranyl. The method was applied to the recovery of uranyl from different water samples.

Treatment of refractory antibody mediated autoimmune disorders with an anti-CD20 monoclonal antibody (rituximab)

BACKGROUND

Rituximab, a chimeric monoclonal anti-CD20 antibody, has recently been used for the treatment of refractory antibody mediated autoimmune diseases such as immune mediated thrombocytopenia and haemolytic anaemia.

PATIENTS

Because of its novel mechanism of action, rituximab was used to treat three patients with refractory systemic antibody mediated autoimmune disorders. The first patient, a 71 year old woman with idiopathic type II mixed essential cryoglobulinaemia, had both dermatological and neurological manifestations with marked renal disease attributed to her cryoglobulinaemia. Patient 2, a 73 year old woman with Goodpasture's syndrome, was refractory to conventional treatment (cyclophosphamide, prednisone, plasmapheresis). She had persistent haemoptysis and haematuria and positive antiglomerular basement membrane antibodies. The third patient, a 75 year old man with primary biliary cirrhosis, myelodysplasia, and systemic immune complex vasculitis, had progressive renal insufficiency, a macular erythematous rash, and severe thrombocytopenia.

RESULTS

Treatment with rituximab resolved all clinical and laboratory manifestations in the three patients.

CONCLUSIONS

Rituximab may be an important therapeutic agent for the treatment of patients refractory or intolerant to corticosteroid or cytotoxic treatment, or both.

Triiodide PVC membrane electrodes based on charge-transfer complexes

Three new electrodes were prepared by incorporating two different charge-transfer complexes and amino crown ether into plasticized PVC membranes. The electrodes showed Nernstian response to triiodide ion over the activity range from 1.0 x 10(-5) to 1.0 x 10(-1) mol x L(-1) with detection limits at approximately 1.0 x 10(-6) mol x L(-1). The resulting electrodes have fast response times (20-30 s) and good stabilities (4 months) and can be used over a wide pH range of 2.5-9.0. The proposed electrodes exhibit anti-Hofmeister behavior with excellent selectivity toward triiodide ion against a wide range of common interferences. Comparative study suggests that amino (aza) crown ether alone or in the form of a charge-transfer complex with iodine, as an ionophore in a PVC liquid membrane, is sensitive to triiodide ion. The electrodes were used as indicator electrodes in potentiometric titration of triiodide ion against thiosulfate ion.

Knee flexors/extensors in gait of elderly and young able-bodied men (II)

In this study the fundamental tasks of muscle activity at the knee during gait in elderly and young able-bodied subjects were identified using principal component analysis (PCA). Role discrepancies between the older and younger subjects for the actions executed by the knee flexors and extensors during the gait cycle were also investigated. The t-test for independent groups was applied to determine significant differences between spatio-temporal and peak muscle moment parameters (P<0.05). PCA as a multivariate classification and curve structure detection method was applied to the sagittal knee muscle moment curves of twenty elderly (72 +/-5.5 years) and twenty young (25 +/- 8.1 years) subjects. The first three principal components (PCs) which accounted for 80% (older) and 93% (younger) of the information were retained for further analysis. Providing stable locomotion was recognised as a major task of the knee in the older subjects, while for the younger subjects the knee contributed to both balance and propulsion. Supporting the body during single limb support should be considered the only common task at the knee level in elderly and young subjects' gait. The lack of muscle power for propulsion might be the reason for not identifying the knee extensor muscle roles in the first three major tasks during elderly gait. Functional asymmetry can be considered the result of a different ordering of the functional roles of the muscles acting at the knee level in elderly and young subjects.