Electrochemically reduced single-layer MoS₂ nanosheets: characterization, properties, and sensing applications

The electrochemical study of single-layer, 2D MoS₂ nanosheets reveals a reduction peak in the cyclic voltammetry in NaCl aqueous solution. The electrochemically reduced MoS₂ (rMoS₂) shows good conductivity and fast electron transfer rate in the [Fe(CN)₆]³⁻/⁴⁻ and [Ru(NH₃)₆]²⁺/³⁺ redox systems. The obtained rMoS₂ can be used for glucose detection. In addition, it can selectively detect dopamine in the presence of ascorbic acid and uric acid. This novel material, rMoS₂, is believed to be a good electrode material for electrochemical sensing applications.

FT-IR spectral studies on certain human urinary stones in the patients of rural area

Fourier transform infrared spectroscopy (FT-IR) has been carried out to analyze the organic and inorganic constituent of human urinary stones. Patient's hailing from Rajah Muthiah Medical College and Hospital, Annamalai University, Tamil Nadu, India was selected for the study. The FT-IR results indicate that stones have different composition, i.e., namely calcium oxalate, calcium phosphate, carbonate apatite and magnesium ammonium phosphate and uric acid. From the spectral and powder X-ray diffraction pattern, the chemical constituents of urinary stones were identified. The quantitative estimations of calcium oxalate monohydrate (COM) 1,620 cm(-1), calcium phosphate (apatite) 1,037 cm(-1), magnesium ammonium phosphate (struvite) 1,010 cm(-1), calcium carbonate 1,460 cm(-1) and uric acid 1,441 cm(-1) were calculated using particular peaks of FT-IR studies. The study reveals that calcium oxalate monohydrate and calcium phosphate type urinary stones were predominant whereas magnesium ammonium phosphate are in moderate level, and calcium carbonate and uric acid are in low. Calcium phosphate is found in all the stones and calcium oxalate monohydrate is found to be higher. Quantitative analyses of urinary stones show that calcium oxalate monohydrate (40%), apatite (30%), magnesium ammonium phosphate (23%) and uric acid (7%) are present in all the urinary stone samples.

3D graphene foam as a monolithic and macroporous carbon electrode for electrochemical sensing

Graphene, a single-atom-thick monolayer of sp(2) carbon atoms perfectly arranged in a honeycomb lattice, is an emerging sensing material because of its extraordinary properties, such as exceptionally high specific surface area, electrical conductivity, and electrochemical potential window. In this study, we demonstrate that three-dimensional (3D), macroporous, highly conductive, and monolithic graphene foam synthesized by chemical vapor deposition represents a novel architecture for electrochemical electrodes. Being employed as an electrochemical sensor for detection of dopamine, 3D graphene electrode exhibits remarkable sensitivity (619.6 μA mM(-1) cm(-2)) and lower detection limit (25 nM at a signal-to-noise ratio of 5.6), with linear response up to ∼25 μM. And the oxidation peak of dopamine can be easily distinguished from that of uric acid - a common interferent to dopamine detection. We envision that the graphene foam provides a promising platform for the development of electrochemical sensors as well as other applications, such as energy storage and conversion.

[Surface-enhanced Raman spectroscopic analysis of uric acid]

Based on Ag nanoparticles as the surface-enhanced Raman spectroscopy (SERS)-active nanostructure, the SERS of uric acid was presented in the paper. The absorption spectroscopies of uric acid and the mixture of silver colloids and uric acid were measured. The possible enhancing mechanism of the uric acid on silver colloid was speculated. The characteristic SERS bands of uric acid were tentatively assigned. The influence of absorption time and different ion on the SERS of uric acid were also discussed. The SERS spectral intensity changes linearly with the uric acid concentration, which indicated that the SERS might provide a new kind of direct and fast detecting method for the detection of uric acid. The detection limit of uric acid in silver sol is found to be 1 mg/L.

Squeeze-chip: a finger-controlled microfluidic flow network device and its application to biochemical assays

We designed and fabricated a novel microfluidic device that can be operated through simple finger squeezing. On-chip microfluidic flow control is enabled through an optimized network of check-valves and squeeze-pumps. The sophisticated flow system can be easily constructed by combining a few key elements. We implemented this device to perform quantitative biochemical assays with no requirement for precision instruments.

Tellurium-nanowire-coated glassy carbon electrodes for selective and sensitive detection of dopamine

Tellurium-nanowire-coated glassy carbon electrodes (TNGCEs) have been fabricated and employed for selective and sensitive detection of dopamine (DA). TNGCEs were prepared by direct deposition of tellurium nanowires, 600 ± 150 nm in length and 16 ± 3 nm in diameter, onto glassy carbon electrodes, which were further coated with Nafion to improve their selectivity and stability. Compared to the GCE, the TNGCE is more electroactive (by approximately 1.9-fold) for DA, and its selectivity toward DA over ascorbic acid (AA) and uric acid (UA) is also greater. By applying differential pulse voltammetry, at a signal-to-noise ratio of 3, the TNGCE provides a limit of detection of 1 nM for DA in the presence of 0.5mM AA and UA. Linearity (R(2)=0.9955) of the oxidation current at 0.19 V against the concentration of DA is found over the range 5 nM-1 μM. TNGCEs have been applied to determine the concentration of dopamine to be 0.59 ± 0.07 μM in PC12 cells.

[Measurement of purines and uric acid simultaneous in meat with high performance liquid chromatographys]

OBJECTIVE

To determinate adenine, guanine, hypoxanthine, xanthine and uric acid simultaneously in meat, a reversed-phase high performance liquid chromatography (HPLC) was developed.

METHODS

The meat were hydrolyzed with perchloric acid 10% (v/v) in boiling water for 60 mm. After the hydrolysate was adjusted to pH 4, centrifuge , and filtrated with a 0.45 mirom membrane, the supernatants were separated on an Agilent ZORBAX Eclipse XDB-C18 column (250 mm x 4.6 mm i.d., 5 microm) at 25 degrees C with a mobile phase of 7 x 10(-3) mol/L KH2PO4-H3P04(pH 4.0) ,a flow rate of 1.0 ml/ mm, and UV detection at 254 nm.

RESULTS

Each component in the corresponding concentration range showed a good linear relation with its peak area, correlation coefficient r > 0.9999, recovery was 90.0%-107. 5%, RSD was 1.7%-13.3%. In addition to containing four kinds of purines, there was quite amount of uric acid (about 133.7 -86.2 pug/g) in the mentioned meat. The ratio of uric acid to total purine and uric acid was about 7%. The content of total purine in chicken was (1759.3 +/- 64.6) microg/g higher than in rabbit, mutton, pork and beef (1440-1000 microg/g).

CONCLUSION

The validated method is simple, rapid, accurate and reliable to the determination of purines and uric acid in meat.

Biochemical differences in ethnic groups in Durango, Mexico

OBJECTIVE

The aim of this study was to assess biochemical differences between Tepehuano indigenous people, and Mennonite and Mestizo populations of Durango, Mexico.

METHODS

Our study involved 334 volunteers aged 15 to 80 years; 132 Mennonite and 130 Mestizo individuals from Nuevo Ideal Municipality and 72 Tepehuano indigenous people from Mezquital Durango were evaluated. A clinical history and fast determination of aspartate aminotransferase (AST), alanine aminotransferase (ALT), uric acid, urea and creatinine were performed on each studied case.

RESULTS

Statistically significant differences between the three studied groups were found for age, weight and height (P < .05), with higher values observed in men. The highest plasma urea levels were found in Mennonite compared to Mestizo people, followed by the Tepehuano indigenous. Higher biochemical parameters were found in men (vs women) in the studied groups. The percentage of individuals with abnormal levels for AST, ALT and uric acid were higher in Tepehuano indigenous people than in Mestizo, whereas the urea and creatinine percentages were higher in Mestizo people.

CONCLUSION

The differences found on biochemical tests, could be explained by differences in lifestyle such as diet and sanitary habits.

Brain microdialysis in freely moving animals

Brain microdialysis is an analytical technique used for the dynamic monitoring of brain neurochemistry in awake, freely moving animals. This technique requires the insertion of a small dialysis catheter, called a microdialysis probe, into a specific brain region, and its perfusion with an artificial extracellular fluid. The microdialysate samples, obtained from the probe outlet, can be analysed using high-performance liquid chromatography with electrochemical detection for the quantification of oxidizable molecules recovered from the extracellular space. In this chapter, we describe a protocol for performing a microdialysis setup and experiment in freely moving rats and mice. Furthermore, the high-performance liquid chromatographic determination of ascorbic acid, uric acid, catecholamines, indolamines and derivatives is described in detail.

Mineralogical and morphological investigation of kidney stones of a Mediterranean region (Basilicata, Italy)

Kidney stones are a very frequent finding in southern Italy, but stone analysis is not routinely performed. However, it is an important requirement not only for a successful treatment of this disease, but also for the prophylaxis to prevent any recurrence. We therefore set out to analyze 80 kidney stones collected from Basilicata Region (Southern, Italy). X-ray powder diffraction as well as optical and scanning electron microscopy and petrographic thin section analysis have been applied in order to determine the mineralogical and morphological compositions. The internal structure and the relation between major and minor components have facilitated the classification of the kidney stones according to a detailed scheme. As it is known from other country, calcium oxalate stones were the most frequent (59%) [39% mainly composed of whewellite, CaC₂O₄*H₂O and 29% is mainly made of weddellite, CaC₂O₄*2H₂O]. Uric acid stones were abundant too (18%). Calcium phosphate and cystine stone were less. The results of the observations of kidney stones in thin petrographic sections led to the identification of more cores in the same whewellite kidney stones. In some kidney stones the core is not situated in the central zone, which represents the point of attachment on kidney wall. Basilicata kidney stone prevalence is different from the average prevalence determined in other Mediterranean areas. The comparison showed that calcium oxalate stones seem to be more frequent, and there is a high prevalence of uric acid kidney stones and a lower prevalence of phosphate kidney stones, especially hydroxyapatite. The relative increase frequency of uric acid stones in the northern part of the Region may be due to high-purine diets and softness water consumption.

Electrochemical behavior of gold nanoparticles modified nitrogen incorporated tetrahedral amorphous carbon and its application in glucose sensing

Gold nanoparticles (NPs) with 10-50 nm in diameter were synthesized on nitrogen incorporated tetrahedral amorphous carbon (ta-C:N) thin film electrode by electrodeposition. The deposition and nucleation processes of Au on ta-C:N surface were investigated by cyclic voltammetry and chronoamperometry. The morphology of Au NPs was characterized by scanned electron microscopy. The electrochemical properties of Au NPs modified ta-C:N (ta-C:N/Au) electrode and its ability to sense glucose were investigated by voltammetric and amperometric measurements. The potentiostatic current-time transients showed a progressive nucleation process and diffusion growth of Au on the surface of ta-C:N film according to the Scharifker-Hills model. The Au NPs acted as microelectrodes improved the electron transfer and electrocatalytic oxidation of glucose on ta-C:N electrode. The ta-C:N/Au electrode exhibited fast current response, a linear detection range of glucose from 0.5 to 25 mM and a detection limit of 120 microM, which hinted its potential application as a glucose biosensor.

Comparison of salivary antioxidants in healthy smoking and non-smoking men

BACKGROUND

Tobacco use is known as a serious global public health problem, and is also an important risk factor for oral diseases. Saliva is the first biological medium encountered during inhalation of cigarette smoke. Therefore, the main aim of this study was to compare the levels of salivary antioxidants between healthy smoking and non-smoking men.

METHODS

Unstimulated whole saliva samples were collected from 80 men. Forty subjects were smokers with a daily consumption of 20 cigarettes for at least 10 years and 40 subjects were non-smokers. The salivary levels of uric acid, superoxide dismutase, glutathione peroxidase, and peroxidase were measured and compared between studied groups.

RESULTS

The mean levels of salivary superoxide dismutase, glutathione peroxidase, and peroxidase were significantly lower in smokers than non-smokers. There was no statistically significant difference in the salivary uric acid level between smokers and non-smokers.

CONCLUSIONS

Measurement of antioxidant agents in human saliva might be useful for estimating the level of oxidative stress caused by cigarette smoke.

Microwave-assisted synthesis of a core-shell MWCNT/GONR heterostructure for the electrochemical detection of ascorbic acid, dopamine, and uric acid

In this study, graphene oxide nanoribbons (GONRs) were synthesized from the facile unzipping of multiwalled carbon nanotubes (MWCNTs) with the help of microwave energy. A core-shell MWCNT/GONR-modified glassy carbon (MWCNT/GONR/GC) electrode was used to electrochemically detect ascorbic acid (AA), dopamine (DA), and uric acid (UA). In cyclic voltammograms, the MWCNT/GONR/GC electrode was found to outperform the MWCNT- and graphene-modified GC electrodes in terms of peak current. For the simultaneous sensing of three analytes, well-separated voltammetric peaks were obtained using a MWCNT/GONR/GC electrode in differential pulse voltammetry measurements. The corresponding peak separations were 229.9 mV (AA to DA), 126.7 mV (DA to UA), and 356.6 mV (AA to UA). This excellent electrochemical performance can be attributed to the unique electronic structure of MWCNTs/GONRs: a high density of unoccupied electronic states above the Fermi level and enriched oxygen-based functionality at the edge of the graphene-like structures, as revealed by X-ray absorption near-edge structure spectroscopy, obtained using scanning transmission X-ray microscopy.

Printed two-dimensional micro-zone plates for chemical analysis and ELISA

In this study we report a new concept of printing low-cost two-dimensional micro-zone plates for chemical and biochemical assays and ELISA. It is different from the concept of forming multi-zone micro-zones on paper by hydrophobic barriers first reported by Yagoda. Instead, the desired multi-zone micro-zone pattern was first printed using a UV-curable varnish onto a polymer film; then fine powders of cellulose or other materials were applied onto the uncured varnish, allowing the powder to stick to the varnish layer. After UV-curing, the powder particles were fixed by the cured varnish, leading to the formation of porous, water absorbing micro-zones on the polymer film. This type of micro-zone plate has the required liquid handling capacity for a variety of low-volume and portable two-dimensional plates for chemical, biochemical assays and ELISA. By suitably spacing porous micro-zones on a non-porous substrate, this type of plate eliminates inter-zone sample leaking. Rapid colorimetric analysis of the results can be performed using a portable battery-powered colour densitometer or a desktop scanner. By introducing a refractive-index-matching liquid into the micro-zones, the plate can be easily analyzed using transmission instruments. A major advantage of this plate fabrication method is that it enables the printing of different powders or functionalized powders to form micro-zones on a same plate, potentially allowing certain more difficult functionalization of materials to be performed before printing. We demonstrate the assaying performance of the plates using an analytical system that aims to clarify the analytical interference between NO(2)(-) and uric acid (UA) in the analysis of samples where both chemical species are present. We also show that ELISA assays can be performed using this type of plates.

Exogenous corticosterone and nest abandonment: a study in a long-lived bird, the Adélie penguin

Breeding individuals enter an emergency life-history stage when their body reserves reach a minimum threshold. Consequently, they redirect current activity toward survival, leading to egg abandonment in birds. Corticosterone (CORT) is known to promote this stage. How and to what extent CORT triggers egg abandonment when breeding is associated with prolonged fasting, however, requires further investigation. We manipulated free-living male Adélie penguins with CORT-pellets before their laying period. We then examined their behavioral response with respect to nest abandonment in parallel with their prolactin levels (regulating parental care), and the subsequent effects of treatment on breeding success in relieved birds. Exogenous CORT triggered nest abandonment in 60% of the treated penguins ~14 days after treatment and induced a concomitant decline in prolactin levels. Interestingly, prolactin levels in treated penguins that did not abandon their nest were higher at the point of implantation and also after being relieved by females, when compared with abandoning penguins. Among successful birds, the treatment did not affect the number of chicks, nor the brood mass. Our results show the involvement of CORT in the decision-making process regarding egg abandonment in Adélie penguins when incubation is associated with a natural long fast. However, we suggest that CORT alone is not sufficient to trigger nest abandonment but that 1) prolactin levels need to reach a low threshold value, and 2) a rise in proteolysis (i.e. utilization of protein as main energy substrate) seems also to be required.

Carbon-Pt nanoparticles modified TiO2 nanotubes for simultaneous detection of dopamine and uric acid

The present work describes sensing application of modified TiO2 nanotubes having carbon-Pt nanoparticles for simultaneous detection of dopamine and uric acid. The TiO2 nanotubes electrode was prepared using anodizing method, followed by electrodeposition of Pt nanoparticles onto the tubes. Carbon was deposited by decomposition of polyethylene glycol in a tube furnace to improve the conductivity. The C-Pt-TiO2 nanotubes modified electrode was characterized by cyclic voltammetry and differential pulse voltammetry methods. The modified electrode displayed high sensitivity towards the oxidation of dopamine and uric acid in a phosphate buffer solution (pH 7.00). The electro-oxidation currents of dopamine and uric acid were linearly related to the concentration over a wide range of 3.5 x 10(-8) M to 1 x 10(-5) M and 1 x 10(-7) M to 3 x 10(-5) M respectively. The limit of detection was determined as 2 x 10(-10) M for dopamine at signal-to-noise ratio of 3. The interference of uric acid was also investigated. Electro-oxidation currents of dopamine in the presence of fix amount of uric acid represented a linear behaviour towards successive addition of dopamine in range of 1 x 10(-7) M to 1 x 10(-5) M. Furthermore, in a solution containing dopamine, uric acid and ascorbic acid the overlapped oxidation peaks of dopamine and ascorbic acid could be easily separated by using C-Pt-TiO2 nanotubes modified electrode.

Immobilization of uricase enzyme on self-assembled gold nanoparticles for application in uric acid biosensor

An enzyme immobilization matrix is described by preparing a self-assembly of gold nanoparticles (GNPs) over a self-assembled monolayer (SAM) of 3-aminopropyltriethoxysilane (APTES) on an indium-tin-oxide (ITO) coated glass plate. The surface of the GNPs was modified with a mixed (1:9) SAM of 11-mercaptoundecanoic acid (MUA) and 3-mercapto-propionic acid (MPA). The enzyme, uricase was covalently immobilized to the carboxyl groups of the mixed SAM of MUA/MPA through carbodiimide coupling reaction. The whole assembly was constructed on 1 cm2 area of ITO-glass plate and was tested as an amperometric biosensor for the detection of uric acid in aqueous solution. The biosensor assembly was characterized by atomic force microscopy (AFM) and electrochemical techniques. The AFM of the enzyme biosensor assembly reveals an asymmetrical sharp regular island-like structure with an average roughness parameter value of 2.81 nm. Chronoamperometric response was measured as a function of uric acid concentration in aqueous solution (pH 7.4), which exhibits a linear response over a concentration range of 0.07 to 0.63 mM with a sensitivity of 19.27 microAmM(-1) and a response of 25 s with excellent reproducibility. These results are not influenced by the presence of interfering reagents such as ascorbic acid, urea and glucose. GNPs-biomolecule assemblies constructed using this method may facilitate development of new hybrid biosensing materials.

Olea europaea leaf (Ph.Eur.) extract as well as several of its isolated phenolics inhibit the gout-related enzyme xanthine oxidase

In Mediterranean folk medicine Olea europaea L. leaf (Ph.Eur.) preparations are used as a common remedy for gout. In this in vitro study kinetic measurements were performed on both an 80% ethanolic (v/v) Olea europaea leaf dry extract (OLE) as well as on nine of its typical phenolic constituents in order to investigate its possible inhibitory effects on xanthine oxidase (XO), an enzyme well known to contribute significantly to this pathological process. Dixon and Lineweaver-Burk plot analysis were used to determine K(i) values and the inhibition mode for the isolated phenolics, which were analysed by RP-HPLC for standardisation of OLE. The standardised OLE as well as some of the tested phenolics significantly inhibited the activity of XO. Among these, the flavone aglycone apigenin exhibited by far the strongest effect on XO with a K(i) value of 0.52 μM. In comparison, the known synthetic XO inhibitor allopurinol, used as a reference standard, showed a K(i) of 7.3 μM. Although the phenolic secoiridoid oleuropein, the main ingredient of the extract (24.8%), had a considerable higher K(i) value of 53.0 μM, it still displayed a significant inhibition of XO. Furthermore, caffeic acid (K(i) of 11.5 μM; 1.89% of the extract), luteolin-7-O-β-D-glucoside (K(i) of 15.0 μM; 0.86%) and luteolin (K(i) of 2.9 μM; 0.086%) also contributed significantly to the XO inhibiting effect of OLE. For oleuropein, a competitive mode of inhibition was found, while all other active substances displayed a mixed mode of inhibition. Tyrosol, hydroxytyrosol, verbascoside, and apigenin-7-O-β-D-glucoside, which makes up for 0.3% of the extract, were inactive in all tested concentrations. Regarding the pharmacological in vitro effect of apigenin-7-O-β-D-glucoside, it has to be considered that it is transformed into the active apigenin aglycone in the mammalian body, thus also contributing substantially to the anti-gout activity of olive leaves. For the first time, this study provides a rational basis for the traditional use of olive leaves against gout in Mediterranean folk medicine.

Microfluidic paper-based chemiluminescence biosensor for simultaneous determination of glucose and uric acid

In this study, a novel microfluidic paper-based chemiluminescence analytical device (μPCAD) with a simultaneous, rapid, sensitive and quantitative response for glucose and uric acid was designed. This novel lab-on-paper biosensor is based on oxidase enzyme reactions (glucose oxidase and urate oxidase, respectively) and the chemiluminescence reaction between a rhodanine derivative and generated hydrogen peroxide in an acid medium. The possible chemiluminescence assay principle of this μPCAD is explained. We found that the simultaneous determination of glucose and uric acid could be achieved by differing the distances that the glucose and uric acid samples traveled. This lab-on-paper biosensor could provide reproducible results upon storage at 4 °C for at least 10 weeks. The application test of our μPCAD was then successfully performed with the simultaneous determination of glucose and uric acid in artificial urine. This study shows the successful integration of the μPCAD and the chemiluminescence method will be an easy-to-use, inexpensive, and portable alternative for point-of-care monitoring.

Gout and coexisting pseudogout in the knee joint

PURPOSE

We report the unusual case of a 63-year-old man with gout and coexisting pseudogout (calcium pyrophosphate dihydrate crystal deposition disease) affecting the same joint. In this report, we describe the clinical features of the patient in addition to the characteristics of the crystals extracted from his affected joint, examined using compensated polarized microscopy.

METHODS

Synovial fluid and specimens of the lateral meniscus of the patient's knee joint taken during arthroscopy were analyzed using compensated polarized microscopy to evaluate the presence and type of crystals.

RESULTS

Compensated polarized microscopy revealed both monosodium urate (MSU) and calcium pyrophosphate dihydrate (CPPD) crystals extracted from the knee joint.

CONCLUSIONS

Our findings suggest that the coexistence of gout and pseudogout should be considered in the diagnosis of crystal-induced arthritis. Careful crystal evaluation using compensated polarized microscopy may reveal similar cases with MSU and CPPD crystals in the same joint.

[Uric acid nephrolithiasis]

Uric acid nephrolithiasis is frequent accounting for 10% of urinary stones in industrialized countries. Its frequency will increase in the next decades because of the ageing and the increasing prevalence of obesity and type 2 diabetes mellitus. The pathophysiologic defect is an excessively acidic urine pH rather than hyperuricosuria. Undissociated uric acid is poorly soluble in acidic urines (pH < 5.5) but solubility increases when sodium urate forms at higher pH. Insulin resistance may contribute to the development of acidic urine because of higher net acid excretion. Because uric acid kidney stones are radiolucent, diagnosis is based on echography and tomodensitometry. Medical management strategies focus primarily on alkali treatment and/or decreasing hyper-uricosuria.

Simultaneous determination of 3,4-dihydroxyphenylacetic acid, uric acid and ascorbic acid by poly(L-arginine)/multi-walled carbon nanotubes composite film

The poly(L-Arginine)(PArg)-multiwalled carbon nanotubes (MWCNTs) composite film was used to modify glassy carbon electrode (GCE) to fabricate PArg/MWCNTs/GCE through electropolymerization of L-Arginine on MWCNTs/GCE. The PArg/MWCNTs/GCE exhibited high electro-catalytic activities towards the oxidation of 3,4-dihydroxyphenylacetic acid (DOPAC), uric acid (UA), and ascorbic acid (AA), and could be sensitively used for simultaneous determination of DOPAC, AA, and UA in pH 7.4 phosphate-buffered solution (PBS).The linear ranges were 7 microM to 2.7 mM for DOPAC, 3 microM to 1.2 mM for UA, and 70 microM to 1.4 mM for AA. The detection limits were 1.3 microM for DOPAC, 0.7 microM for UA and 20 microM for AA.

Recent improvements in survival in primary systemic amyloidosis and the importance of an early mortality risk score

OBJECTIVE

To examine whether the outcome of patients with primary systemic amyloidosis (AL) has improved over time and to identify predictors of early mortality in patients with AL.

PATIENTS AND METHODS

We studied 2 separate cohorts of patients. The first cohort, consisting of 1998 patients with AL seen at Mayo Clinic between January 1977 and August 2006, was used to examine the trends in overall survival (OS) from diagnosis during this 30-year period. The second cohort, consisting of 313 patients seen between September 2006 and August 2009, was used to validate a model for predicting early mortality.

RESULTS

The 4-year OS from diagnosis improved during each decade of follow-up: 21%, 24%, and 33%, respectively, for the periods 1977-1986, 1987-1996, and 1997-2006 (P<.001). Within the last group (1997-2006), 4-year OS during 1997-1999, 2000-2002, and 2003-2006 was 28%, 30%, and 42%, respectively (P=.02). However, the 1-year mortality remained high during the 30-year period. A risk stratification score using cardiac troponin T, N-terminal probrain natriuretic peptide, and uric acid identified patients at risk of early mortality. The 1-year mortality with 0, 1, 2, or 3 risk factors was 19%, 37%, 61%, and 80%, respectively, in this training cohort of 459 patients. This was confirmed in a validation cohort of 313 patients.

CONCLUSION

Survival in AL has improved over time, with maximum improvement occurring in the past decade. However, early mortality remains high, and prospective identification of patients at risk of early mortality may allow development of risk-adapted strategies.

Clinical significance of uric acid dihydrate in urinary stones

Uric acid crystallizes as an anhydrous compound (UAA), a dihydrate (UAD) or a mixture of both. A monohydrate form is very rare. About 20% of uric acid stones contain a significant amount (≥20%) UAD. It is believed that UAD crystallizes under highly acidic conditions (urine pH ≤ 5.0). Up to now, metabolic data on patients with UAD stones have not been reported in the literature. One hundred and fifty patients with pure uric acid calculi were studied. Stone analysis was performed using X-ray diffraction. According to the stone analysis, they were divided in two groups: 1. UAD (≥20% UAD), 2. UAA (<20% UAD). In all patients the following parameters were examined: age, sex, number of recurrences, body mass index (BMI); blood: creatinine, uric acid, calcium, sodium, and potassium; urine: pH-profiles, volume, calcium, uric acid, citrate, ammonia, and urea. Group 1 (≥20% UAD) consisted of 33 patients and group 2 (<20% UAD) of 117 patients. Between these groups, there was a significant difference concerning the number of recurrences, the urine volume, and the urinary excretion of calcium. Patients with ≥20% dihydrate had a mean BMI of 31.6 ± 7.5, a mean number of recurrences of 0.24 ± 0.44, an urine volume of 2.6 ± 0.8 l/24 h, and a calcium excretion of 4.5 ± 2.2 mmol/24 h, whereas those with <20% dihydrate had BMI of 29.9 ± 5.0, 1.10 ± 1.42 recurrences, urine volume of 2.3 ± 1.2 l/24 h, and calcium excretion of 3.2 ± 2.4 mmol/24 h. All the other parameters tested were not significantly different. For the first time, our study shows metabolic data in uric acid patients with a significant amount of UAD. The comparison between this group and those patients with <20% UAD revealed that the first group is less prone to develop recurrences. This is a relevant difference concerning the necessity of metaphylactic measures. We could not confirm in patients with dihydrate if the urinary pH is more acid than in those with insignificant amounts of dihydrate. The higher 24-h urine volume, the higher excretion of calcium, and the higher BMI in the UAD group may be of pathophysiological relevance and requires further attention.

Insulin resistance profile among siblings of type 2 diabetes mellitus (preliminary study)

AIM

to obtain prevalence of insulin resistance among siblings of subjects with type 2 DM and their metabolic abnormality profiles as measured by their BMI, waist circumference (WC), blood pressure, glucose intolerance, concentration of triglyceride, HDL cholesterol, and uric acid.

METHODS

a preliminary, cross sectional study conducted among 30 siblings from seven type 2 DM subjects under medical treatment in Dr. Cipto Mangunkusumo Hospital and other places where the subjects lived. Those subjects underwent interviews, physical examination including weight, height, abdominal circumference, blood pressure and laboratory examinations including glucose tolerance test, fasting insulin, triglycerides, HDL cholesterol and uric acid level. Data processed to obtain body mass index (BMI), homeostasis model assessment of insulin resistance (HOMA-IR) and HOMA-IR cut-off, which is determined based on 75 percentile. The criteria of hypertension, dyslipidemia, central obesity and hyperglycemia are based on Asian modification NCEP/ATP III criteria for metabolic syndrome. Hyperuricemia is diagnosed based on uric acid level >7mg/dl in men and >6 mg/dl in women.

RESULTS

the prevalence of insulin resistance among siblings of type 2 DM in this study is 26.67% with the proportion in each family varies from 0% to 75%. The most metabolic component found in this study is central obesity (56.7%), followed by hypertension (46.7%), decreased HDL cholesterol level (26.6%), hyper-triglyceridemia (26.6%) and hyperglycemia (20%). As many as three-quarters of subjects with insulin resistance have BMI >25 kg/m2. Among subjects with insulin resistance, all have central obesity, half of them have hypertension, decreased HDL cholesterol level and hyper-triglyceridemia. While hyperglycemia is found in 37.5% subjects.

CONCLUSION

the prevalence of insulin resistance among siblings of type 2 DM in this study was 26.67% with the proportion in each family varies between 0-75%. Central obesity is the most metabolic component commonly found.

Urinary alkalization for the treatment of uric acid nephrolithiasis

Three major conditions control the potential for uric acid stones: the quantitative excretion of uric acid, the volume of urine as it affects the urinary concentration of uric acid and the urinary pH. However, the most important factor for uric acid stone formation is acid urinary pH that is a prerequisite for uric acidic stone formation. Indeed the goal standard of urinary alkalization is to achieve a pH of 6-6.5. Administration of alkali should be titrated appropriately by pH paper to record urinary pH until a steady state is achieved. Alkali therapy such as sodium bicarbonate and potassium citrate has been advocated on the basis of established clinical experience, although potassium citrate should be preferred because it may avoid the complication of calcium salt precipitation. Recently it has been reported the clinical efficacy of therapy with potassium citrate/potassium bicarbonate for dissolution of radiolucent stones respect to control study period (only water daily intake of 1500 ml). Furthermore, mean urinary pH was significantly continuously higher during the alkali treatment study in comparison to the control study period, even though the mean of urinary volumes were similar in the two periods. In conclusion urinary alkalization with maintaining continuously high urinary pH values, could be the treatment of choice for stone dissolution and prevention of uric acid stones.

Assessment of kidney stone and prevalence of its chemical compositions

Kidney stone analysis is the test done on the stone which cause problems when they block the flow of urine through or out of the kidneys. The stones cause severe pain and are also associated with morbidity and renal damage. There is also no clear understanding on the relative metabolic composition of renal calculi. Hence, the study is aimed to find out the chemical composition of it which can guide treatment and give information that may prevent more stones from forming. The study was carried out on the stones that had been sent to the department of Biochemistry (n = 99; M = 61; F = 38; Mean age: 33.6 +/- 14.4 years) Approximately 98.9% of stones were composed of oxalate, 95.9% of Calcium, 85.8% of phosphate, 62.6% of Urate, 46.4% of Ammonium and very few percentages of Carbonate.

Pilot study of probiotic dietary supplementation for promoting healthy kidney function in patients with chronic kidney disease

INTRODUCTION

Uremic syndrome consists of nitrogenous waste retention, deficiency in kidney-derived hormones, and reduced acid excretion, and, if untreated, may progress to coma and eventual death. Previous experience suggests that oral administration of a probiotic formulation of selected microbial strains may extend renoprotection via intraintestinal extraction of toxic waste solutes in patients with chronic kidney disease (CKD)stages 3 and 4. This report presents preliminary data from a pilot study.

METHODS

This was a 6-month prospective, randomized, double-blind, placebo-controlled crossover trial of a probiotic bacterial formulation conducted in four countries, at five institutions, on 46 outpatients with CKD stages 3 an nd 4: USA (n=10), Canada (n=113), Nigeria (n=115), and Argentina (n=8). Outcomes were compared using biochemical parameters:blood urea nitrogen (BUN), serum creatinine, and uric acid. General well-being was assessed as a secondary parameter by a quality of life (QQOL) questionnaire on a subjective scale of 1-10.

RESULTS

Oral ingestion of probiotics (90 billion colony forming units [CFUs]/day) was well tolerated and safe during the entire trial period at all sites. BUN levels decreased in 29 patients (63%, P<0.05), creatinine levels decreased in 20 patients (43%, no statistical significance), and uric acid levels decreased in 15 patients (33%, no statistical significance). Almost all subjects expressed a perceived substantial overall improvement in QOL (86%, P<0.05).

CONCLUSION

The main outcomes of this preliminary trial include a significant reduction of BUN, enhanced well-being, and absence of serious adverse effects, thus supporting the use of the chosen probiotic formulation for bowel-based toxic solute extraction. QOL and BUN levels showed statistically significant differences in outcome (P<0.05) between placebo and probiotic treatment periods at all four sites (46 patients). A major limitation of this trial is the small sample size nd elated inconsistencies.

The composition and quantitative analysis of urinary calculi in patients with renal calculi

To get complete information about the chemical composition and physicochemical principles underlying the formation of stone there is a need for more precise information. At present there is no single analytical procedure that provides an exact quantitative analysis of urinary calculi. In this present procedure it is assumed that only calcium oxalate monohydrate, hydroxyapatite, or magnesium ammonium phosphate hexahydrate are present in stone, therefore the percent chemical composition of stone is calculated on the basis of molecular weight of an element and related molecular formula of the stone. By analysis of 100 stones the chemical composition observed with Mean +/- SD value for calcium is 25.68 +/- 5.38, for Calcium oxalate hydrate crystal is 32.84 +/- 17.28 which contains oxalic acid 20.35 +/- 10.70, for Apatite crystal is found to be 41.70 +/- 16.56 which contains inorganic phosphate 8.09 +/- 3.08. Total uric acid found in these stones is 27.12 +/- 11.42. Major component are calcium oxalate 32.8% (combined monohydrate and dihydrate), Phosphate 41.7%, Magnesium ammonium phosphate hexahydrate 3.3% and uric acid 27.1%. No pure stone was obtained. Calcium oxalate was present in nearly all stones, and the majority of renal calcium stones contains mixtures of calcium oxalate and calcium phosphates in addition some contains uric acid or magnesium ammonium phosphate. The mixture of calcium oxalate/uric acid/magnesium ammonium phosphate hexa hydrate has never been observed.

High follicular fluid adenosine levels may be pivotal in the metabolism and recycling of adenosine nucleotides in the human follicle

This study investigated the biochemical relationship between human follicular/oocyte maturity and the levels of follicular fluid purines. Intrafollicular levels of purine metabolites and creatinine are associated with oocyte presence, and the presence of such high levels of adenosine indicates a privileged site with no adenosine deaminase activity. Subgrouping according to oocyte recovery and fertilization revealed differences in correlation between the purine metabolites: Only where an oocyte was recovered and subsequently fertilized did follicular fluid adenosine, adenine, and hypoxanthine levels correlate with each other. Significantly, purines' correlation with levels of the terminal degradation product, uric acid, could only be seen in failed fertilization samples. Given the established metabolic pathways for adenosine triphosphate/adenosine diphosphate/adenosine monophosphate degradation, the results indicate maximization of 2 purine salvage pathways (from adenine and hypoxanthine) that pivot on the presence of high adenosine levels. Such optimized recovery may be necessary to build a store of salvaged adenosine phosphate for oocyte survival.

Feline urate urolithiasis

This retrospective case control study describes associations between feline urate urolithiasis and breed, age, gender, and urine composition. Data from cases of feline uroliths submitted to the Canadian Veterinary Urolith Centre (CVUC) between February 2, 1998 and July 7, 2007 were reviewed. There were 10 083 feline uroliths examined, including 385 ammonium urate, 13 uric acid, and 21 mixed struvite/urate uroliths. The Egyptian Mau, Birman, and Siamese breeds were significantly predisposed to urate urolithiasis [odds ratio (OR) = 118, 95% confidence interval (CI) = 38.2 to 510, P < 0.001], (OR = 9.1, 95% CI = 2.0 to 32, P < 0.001) and (OR = 3.9, 95% CI = 2.5 to 5.9, P < 0.001), respectively. Urate urolithiasis was more frequent in younger cats (mean age 6.3 versus 7.1 y in cats with other uroliths, P < 0.0001) and in male cats (P = 0.024). The association between Egyptian Maus and urate urolithiasis was remarkable. The association in Siamese cats is consistent with prior reports, and the association with Birman cats requires further study.

An update on inflammatory arthropathies including pharmacologic management and preoperative considerations

This article provides an update and overview to the clinical presentations of inflammatory arthropathies. Subtleties to clinical presentations are discussed. Clues are presented which helps the reader arrive at more precise diagnostic labeling. Additionally, pharmacotherapy will be discussed, including precautions in considering the best therapy for the patient with suspected inflammatory, autoimmune, degenerative or neuropathic pain conditions. Finally, preoperative evaluations, management and risks of this patient population are reviewed. Emphasis will be on whether "cardiac clearance" should be requested based on an easy to use algorithm of cardiac risk factors. Finally recommendations based on recent literature of whether immunosuppressants should be withheld preoperatively.

Twenty four hours urine and serum biochemical parameters in patients with urolithiasis

From the analysis of various urinary constituents and the estimation of serum parameters, it is now possible to identify the risk factors responsible for or contributing for stone formation metabolic factor included calcium, oxalate, uric acid, citrate and pH. Environmental factors where total volume, sodium, phosphate and magnesium. Urinary citrate and magnesium found to be lower in stone formers. The levels of serum parameters like calcium, sodium and intact parathyroid hormone (IPTH) is higher than normal. Where as potassium and magnesium is found to be lower than normal. Higher level of IPTH is associated with primary hyperparathyroidism and is related with stone formation in-patient with urolithiasis. Serum levels of phosphorus, uric acid and Creatinine found to be normal.

Construction of uric acid biosensor based on biomimetic titanate nanotubes

A uric acid biosensor has been fabricated through the immobilization of uricase on glassy carbon electrode modified by biomimetic titanate nanotubes of high specific surface area synthesized by hydrothermal decomposition. The so-constructed biosensor presents a high affinity to uric acid with a small apparent Michaelis-Menten constant of only 0.66 mM. The biosensor exhibits fairly good electrochemical properties such as the high sensitivity of 184.3 microAcm(-2)mM(-1), the fast response of less than 2 s, as well as the wide linear range from 1 microM to 5 mM. These performances indicate that titanate nanotubes could provide a favorable microenvironment for uricase immobilization, stabilize its biological activity, and function as an efficient electron conducting tunnel to facilitate the electron transfer. This suggests an important potential of titanate nanotubes in uric acid biosensors.

Comparison of free fructose and glucose to sucrose in the ability to cause fatty liver

BACKGROUND

There is evidence that disaccharide sucrose produce a greater increase in serum fructose and triglycerides (TGs) than the effect produced by their equivalent monosaccharides, suggesting that long-term exposure to sucrose or fructose + glucose could potentially result in different effects.

AIM OF THE STUDY

We studied the chronic effects of a combination of free fructose and glucose relative to sucrose on rat liver.

METHODS

Rats were fed either a combination of 30% fructose and 30% glucose (FG) or 60% sucrose (S). Control rats were fed normal rat chow (C). All rats were pair fed and were followed for 4 months. After killing, blood chemistries and liver tissue were examined.

RESULTS

Both FG-fed- and S-fed rats developed early features of metabolic syndrome when compared with C. In addition, both diets induced hepatic alterations, including variable increases in hepatic TG accumulation and fatty liver, an increase in uric acid content in the liver, as well as an increase in hepatic levels of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-alpha) measured in liver homogenates.

CONCLUSIONS

Diets containing 30% of fructose either as free fructose and glucose, or as sucrose, induce metabolic syndrome, intrahepatic accumulation of uric acid and TGs, increased MCP-1 and TNF-alpha as well as fatty liver in rats. It will be relevant to determine clinically whether pharmacological reduction in uric acid levels might have a therapeutic advantage in the treatment of non-alcoholic fatty liver disease.

HPLC study of uremic fluids related to optical dialysis adequacy monitoring

PURPOSE

The aim of this study was to investigate uremia-related high-performance liquid chromatography (HPLC) ultraviolet (UV) absorbance profiles of serum and spent dialysate and to study the removal of uremic retention solutes in connection with optical dialysis adequacy monitoring.

METHODS

10 uremic patients were investigated using online spectrophotometry at a wavelength of 280 nm over the course of 30 hemodialysis treatments. The dialysate and blood samples were taken and analyzed simultaneously using standard biochemical methods and reversed-phase HPLC. Filters with cutoff at 3 kDa and 70 kDa were used for the pre-treatment of the serum. The chromatographic peaks were detected by a UV detector at wavelengths of 254 and 280 nm.

RESULTS

This study indicated that the main solute responsible for UV absorbance in the spent dialysate is a low-molecular-weight, water-soluble, non-protein-bound compound uric acid (UA). Three additional uremic retention solutes - creatinine (CR), indoxyl sulphate (IS) and hippuric acid (HA) - were identified from the HPLC profiles. The number of detected HPLC peaks was not significantly different for a serum filtered through the 3 kDa or 70 kDa cutoff filters, and was lower for the spent dialysate, indicating that the molecular weight (MW) of the main UV chromophores in the uremic fluids did not exceed 3 kDa. The reduction ratio (RR) estimated by the total area of HPLC peaks at 254 nm and 280 nm in the serum and by the online UV absorbance at 280 nm was best related to the removal of small water-soluble non-protein bound solutes like urea (UR), CR and UA.

CONCLUSIONS

The present study contributes new information on the removal of uremic retention solutes during hemodialysis and on the origin of the optical dialysis adequacy monitoring signal.

Identification of human calculi with time-of-flight secondary ion mass spectrometry

Time-of-flight secondary ion mass spectrometry was used to study four human calculi and to compare the results with those from twelve commercially available urinary calculi minerals including three organic compounds (L-cystine, uric acid and sodium urate). Phase identification of calcium phosphate compounds was carried out by considering the relative ion abundances of [Ca(2)O](+) and [CaPO(2)](+). Deprotonated [M-H](-) and protonated [M+H](+) uric acid were detected and used for component recognition in pure uric acid and in the mixed samples of struvite, calcium oxalate and uric acid. Iodine related to the medical history of a patient was also detected.

Concentration of uric acid removed during dialysis. Estimated by multi wavelength and processed ultra violet absorbance spectra

The aim of this study was to estimate the concentration of uric acid (UA) optically by using original and processed ultra violet (UV) absorbance spectra's of the spent dialysate. Also the effect of using several wavelengths for estimation was examined.

[Clinical assessment of ammonium acid urate urinary calculi]

We investigated the patients with ammonium acid urate (AAU) calculi in relation to dietary history, habit and lifestyle. From April, 2002 to March, 2009, AAU calculi were found in 9 patients (0.66) out of 1,365 cases of stones. Three cases were pure, and 6 were mixed stones. We examined the risk factor of this stone generation, "continuation of malnutrition and dehydration" were seen in 5, "continuing urinary tract infection" was seen in 4 and "continuation of super-saturation of uric acid in urine" was seen in 3 cases. All the patients with "continuation of malnutrition and dehydration" were women, and 4 patients had a history of severe body weight loss. 2 patients were dieting consciously, and the other 2 were eating a poorly balanced diet unconsciously. One patient had no notable past history, but malnutrition was detected in blood examination. It is suggested that AAU calculi is generated even by dieting at a usual level. Compared with the report in the United States, obesity and inflammatory bowel disease were not major risk factors, and "continuation of malnutrition and dehydration" is the major factor in Japan.

History, epidemiology and regional diversities of urolithiasis

Archeological findings give profound evidence that humans have suffered from kidney and bladder stones for centuries. Bladder stones were more prevalent during older ages, but kidney stones became more prevalent during the past 100 years, at least in the more developed countries. Also, treatment options and conservative measures, as well as 'surgical' interventions have also been known for a long time. Our current preventive measures are definitively comparable to those of our predecessors. Stone removal, first lithotomy for bladder stones, followed by transurethral methods, was definitively painful and had severe side effects. Then, as now, the incidence of urolithiasis in a given population was dependent on the geographic area, racial distribution, socio-economic status and dietary habits. Changes in the latter factors during the past decades have affected the incidence and also the site and chemical composition of calculi, with calcium oxalate stones being now the most prevalent. Major differences in frequency of other constituents, particularly uric acid and struvite, reflect eating habits and infection risk factors specific to certain populations. Extensive epidemiological observations have emphasized the importance of nutritional factors in the pathogenesis of urolithiasis, and specific dietary advice is, nowadays, often the most appropriate for prevention and treatment of urolithiasis.

Incidence of Type 2 diabetes in the elderly German population and the effect of clinical and lifestyle risk factors: KORA S4/F4 cohort study

AIMS

To determine the incidence of Type 2 diabetes in an elderly population in Germany and its association with clinical and lifestyle factors.

METHODS

Oral glucose tolerance tests (OGTT, World Health Organization criteria) were carried out in a random sample of 1353 subjects (age group 55-74 years; 62% response) in Augsburg (Southern Germany) (1999-2001). The cohort was re-investigated in 2006-2008. Of those individuals without diabetes (baseline), 887 (74%) participated in the follow-up.

RESULTS

Ninety-three (10.5%) developed diabetes during the 7-year follow-up period {standardized incidence rates [95% confidence interval (CI)] per 1000 person-years: total 15.5; 12.6, 19.1; men 20.2; 15.6, 26.1; women 11.3; 7.9, 16.1}. In both sexes, those who developed diabetes were slightly older, were more obese, had a more adverse metabolic profile (higher glucose values, HbA(1c), fasting insulin, uric acid, and triglycerides) and were more likely to have hypertension at baseline than were participants remaining free of diabetes (P < 0.05). On stepwise logistic regression, age, parental diabetes, body mass index, uric acid, current smoking, HbA(1c) and fasting and 2-h glucose (OGTT) were strong predictors of diabetes incidence. The risk of diabetes was higher in subjects with isolated impaired glucose tolerance (odds ratio 8.8; 95% CI 5.0, 15.6) than in isolated impaired fasting glucose (4.7; 2.2, 10.0), although the difference did not reach statistical significance.

CONCLUSIONS

For the first time, we have estimated the incidence of Type 2 diabetes in an elderly German cohort and demonstrated that it is among the highest in Europe. The OGTT appears to be useful in identifying individuals with high Type 2 diabetes risk. Our results support a role of smoking in the progression to diabetes.