Ultrasensitive Detection of Hydrogen Peroxide Using Methylene Blue Grafted on Molecular Wires as Nanozyme with Catalase-like Activity

In this study, we present the development of an electrochemical sensor designed for ultrasensitive detection of endogenous H2O2. This sensor relies on signal amplification achieved through nanozyme activity exhibited by methylene blue (MB) grafted onto a peptide support. The sensor exhibited excellent selectivity and sensitivity, with a limit of detection of 18 nM and a linear detection range of 20-200 nM. Thus, we have validated the concept of the MB-peptide system, serving as both an electroactive label and a catalyst for H2O2 decomposition under electrochemical conditions. The implemented signal amplification system enables the rapid detection of H2O2, with an overall assay time of 1-2 min, a significant improvement compared to amperometric detection using surface-immobilized enzymes.

A New Highly Sensitive Electrochemical Biosensor for Ethanol Detection Based on Gold Nanoparticles/Reduced Graphene Oxide/Polyallylamine Hydrochloride Nanocomposite

A highly sensitive electrochemical biosensor for ethanol based on a screen-printed electrode modified with gold nanoparticles-electrochemically reduced graphene oxide-poly (allylamine hydrochloride) nanocomposite (AuNPs-ERGO-PAH) is reported in this work. Ethanol was oxidized in the presence of the oxidized form of the nicotinamide adenine dinucleotide (NAD+) in a reaction catalyzed by alcohol dehydrogenase (ADH) immobilized in sol-gel. The AuNPs-ERGO-PAH nanocomposite was used as a transducer for the electrocatalytic oxidation of the reduced form the nicotinamide adenine dinucleotide (NADH) produced in the enzyme reaction. Under the optimal conditions, the ethanol biosensor exhibits a wide dynamic range from 0.05 to 5 mM with a low detection limit of 10 µM (S/N = 3) and a high sensitivity of 44.6 ± 0.07 µA/mM·cm2 for the linear range between 0.05 and 0.2 mM. The biosensor response was stable for up to 6 weeks. Furthermore, the developed biosensor has been used to detect ethanol in alcoholic beverages with good results, suggesting its potential application in various fields, including fermentation processes and food quality control.

Strategies for Surface Design in Surface Plasmon Resonance (SPR) Sensing

Surface plasmon resonance (SPR) comprises several surface-sensitive techniques that enable the trace and ultra-trace detection of various analytes through affinity pairing. Although enabling label-free, sensitive detection and real-time monitoring, several issues remain to be addressed, such as poor stability, non-specific adsorption and the loss of operational activity of biomolecules. In this review, the progress over sensor modification, immobilization techniques and novel 2D nanomaterials, gold nanostructures and magnetic nanoparticles for signal amplification is discussed. The advantages and disadvantages of each design strategy will be provided together with some of the recent achievements.

AMINO ACIDS METABOLOMIC SIGNATURE OF BLOOD PRESSURE VARIABILITY In Type 2 Diabetes

Context

Accumulating data supports the key role of disrupted amino acids (AAs) metabolism in diabetes. Conflicting data regarding the relevance of serum AAs in diabetes and hypertension suggest that their relationship needs further investigation.

Objective

To investigate serum AAs as biomarkers of increased BP variability evaluated during 24-hour ambulatory BP monitoring in the presence of type 2 diabetes.

Design

Cross-sectional.

Subjects and Methods

We analyzed serum AAs using targeted metabolomics (ultrahigh-performance liquid chromatography/mass spectrometry) in patients with type 2 diabetes (n=80). BP variability was assessed using 24-hour ambulatory BP monitoring. Participants were divided into two groups based on the 24-hour diastolic BP variability median value.

Results

Aspartic acid, isoleucine, leucine, and phenylalanine were significantly lower, while glutamine was significantly higher in the group with higher diastolic BP variability (p-value <0.05 and variable importance in the projection >1). Corresponding pathways identified as disrupted in patients with diabetes and a higher 24-hour diastolic BP variability were phenylalanine, tyrosine, and tryptophan biosynthesis, phenylalanine metabolism, and alanine, aspartate, and glutamate metabolism (pathway impact value >0).

Conclusions

We identified specific changes in serum AAs and target AAs pathways in relation to increased 24-hour diastolic BP variability in patients with type 2 diabetes.

Early detection of cannabinoids in biological samples based on their affinity interaction with the growth hormone secretagogue receptor

Herein we report on the early detection of cannabinoids in urine samples according to their affinity profiles in competitive assays with labelled ghrelin (GHR). We have demonstrated for the first time that cannabidiol (CBD) and 11-nor-Δ⁹-tetrahydrocannabinol-9-carboxylic acid (carboxy-THC) act as extracellular ligands for the growth hormone secretagogue receptor (GHS-R1a), strongly promoting the binding of ghrelin (GHR), the endogenous ligand of GHS-R1a. The affinity profiles of CBD and carboxy-THC are significantly different from the profiles of synthetic GHR mimetics such as CJC-1295 or [D-Arg¹-D-Phe⁵-D-Trp^7,9-Leu¹¹]-Substance P peptides, which are the most common interferents; the cannabinoids promoted the GHR/GHS-R1a interaction, while the ghrelin mimetics acted rather as competitive inhibitors. The analysis of 1:4 diluted urine samples proved that the proposed method displays good linearity and sensitivity in the range of 5-30 ng/mL for both CBD and carboxy-THC, whereas GHR mimetics display no interference at concentrations up to 100 ng/mL. The results were validated by comparison with the gas chromatography tandem mass spectrometry reference method. CBD may exert the same promoting effect on the interaction of GHS-R1a with other GHR mimetics listed as performance-enhancing substances.

METABOLOMIC ANALYSIS OF NORMAL WEIGHT, HEALTHY AND UNHEALTHY OBESITY: AMINO ACID CHANGE ACROSS THE SPECTRUM OF METABOLIC WELLBEING IN WOMEN

Context

Obesity is a complex and heterogeneous disorder with multiple phenotypes described. Although metabolomic biomarkers of obesity have been extensively studied, biomarkers of obesity phenotypes and differences between these phenotypes and normal-weight (NW) persons have been less investigated.

Objective

The objective of this cross-sectional analysis was to investigate serum amino acids (AA) as markers of metabolic alterations in obesity phenotypes and NW.

Design

Cross-sectional.

Subjects and Methods

By targeted metabolomics we analyzed serum samples of 70 women using ultrahigh-performance liquid chromatography/mass spectrometry. Participants were divided into 3 groups: NW, metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUHO).

Results

Five AAs were significantly different between study groups: cysteine, methionine, asparagine, glutamine, and lysine (p-value <0.05 and variable importance in the projection >1). Cysteine increased linearly with metabolic unwellness from NW to MUHO. Lysine and glutamine were significantly higher, and asparagine was significantly lower in NW and MHO than in MUHO.

Conclusions

By trend and group analysis we identified specific changes in serum AAs along with the progression of metabolically unwellness.

Advances in Electrochemical Impedance Spectroscopy Detection of Endocrine Disruptors

Endocrine disruptors (EDs) are contaminants that may mimic or interfere with the body's hormones, hampering the normal functions of the endocrine system in humans and animals. These substances, either natural or man-made, are involved in development, breeding, and immunity, causing a wide range of diseases and disorders. The traditional detection methods such as enzyme linked immunosorbent assay (ELISA) and chromatography are still the golden techniques for EDs detection due to their high sensitivity, robustness, and accuracy. Nevertheless, they have the disadvantage of being expensive and time-consuming, requiring bulky equipment or skilled personnel. On the other hand, early stage detection of EDs on-the-field requires portable devices fulfilling the Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment free, Deliverable to end users (ASSURED) norms. Electrochemical impedance spectroscopy (EIS)-based sensors can be easily implemented in fully automated, sample-to-answer devices by integrating electrodes in microfluidic chips. The latest achievements on EIS-based sensors are discussed and critically assessed.

Biosensors for Antioxidants Detection: Trends and Perspectives

Herein we review the recent advances in biosensors for antioxidants detection underlying principles particularly emphasizing advantages along with limitations regarding the ability to discriminate between the specific antioxidant or total content. Recent advances in both direct detection of antioxidants, but also on indirect detection, measuring the induced damage on DNA-based biosensors are critically analysed. Additionally, latest developments on (bio)electronic tongues are also presented.

Early Detection of Growth Hormone Secretagogue Receptor Antagonists Exploiting Their Atypical Behavior in Competitive Assays

We report the proof-of-concept of a bioaffinity format designed for the early detection of growth hormone secretagogue receptor (GHS-R1a) antagonists in urine samples. We exploit here their atypical behavior in competitive experiments with labeled ghrelin (GHR), namely, the strong promoting effect on the GHR/GHS-R1a interaction at low molar ratios GHR/antagonist. The antagonists potentiate the GHR/GHS-R1a interaction, and they display the same effect on the interaction of GHS-R1a with other agonists listed as doping agents. The developed assay allows the estimation of affinity constants of ligand/receptor and antagonist/receptor binding and is amenable to optical, electrochemical, and mass-sensitive detection. The estimated affinity constants for GHR/GHS-R1a and antagonist/GHS-R1a in the absence of G proteins are in good agreement with recently reported data.

THE ROLE OF ADIPONECTIN AND TOLL-LIKE RECEPTOR 4 GENE POLYMORPHISMS ON NON-PROLIFERATIVE RETINOPATHY IN TYPE 2 DIABETES MELLITUS PATIENTS. A CASE-CONTROL STUDY IN ROMANIAN CAUCASIANS PATIENTS

Context

Persistent inflammation and impaired neovascularization are important contributors to the development of diabetic retinopathy (DR). Gene polymorphisms of adiponectin (APN) were demonstrated to have an important role on the plasma level and activity of adiponectin. APN has anti-inflammatory, anti-diabetic and anti-atherogenic properties. Toll-Like Receptor 4 (TLR4) is a critical mediator of innate immunity. Polymorphisms in TLR-4 gene were shown to be associated with impaired inflammatory response in diabetes.

Objective

The aim of the study was to analyze the association of +276G>T variant of APN gene and Asp299Gly and Thr399Ile of TLR-4 gene variants in relationship with T2DM and DR in an Eastern European population group.

Design

The distribution of the mutant alleles in 198 T2DM patients with DR and 200 non-T2DM controls was examined. Genomic DNA from T2DM patients and healthy controls genotyped through the use of PCR-RFPL assay.

Results

Genotype and allele frequencies of the Asp299Gly and Thr399Ile polymorphisms differed between T2DM patients and non diabetic subjects (P<0.001). Moreover, the presence of the minor alleles of these polymorphisms were significantly identified as protective factors against T2DM, under a dominant model of Fisher's exact test (χ2=4.988, phi=0.745, OR=0.767, 95% CI=0.602-0.867, P<0.001; respectively χ2=5.254, phi=0.820, OR=0.487, 95% CI=0.211-0.648, P<0.001). Genotype analysis for the adiponectin 276G>T gene polymorphism yielded no significant association with T2DM, but revealed a borderline significance for the association with DR (χ2=5.632, phi=0.423, OR =1.101, 95% CI=0.887-1.203, P=0.009).

Conclusions

We found an association between the TLR4 Asp299Gly and Thr399Ile polymorphisms and protection for DR. The APN genetic polymorphism is not associated with T2DM.

DIETARY PATTERNS AND THEIR ASSOCIATION WITH OBESITY: A CROSS-SECTIONAL STUDY

Context

Scarce data on dietary habits in Eastern European countries is available and reports investigated individual food items and not dietary patterns in these populations.

Objective

To identify dietary patterns and to explore their association with obesity in a sample from Romanian population.

Design

Cross-sectional.

Subjects and Methods

This was an analysis of data collected from 1398 adult participants in ORO study. Data on lifestyle, eating habits and food frequency consumption were collected.

Results

By principal component analysis we identified 3 dietary patterns explaining 31.4% of the diet variation: High meat/High fat pattern, Western pattern and Prudent pattern. High meat/High fat pattern was associated with male gender, lower educational level, living in a rural, smoking and a higher probability for the presence of obesity (OR 1.2 [95%CI: 1.1-1.4]). Western pattern was associated with younger age, a higher level of physical activity and smoking. Prudent pattern was associated with older age, female gender, a higher level of physical activity, not smoking status and a lower probability for the presence of obesity (OR 0.8 [95%CI: 0.7-0.9]).

Conclusions

This study provides for the first-time information on the association between dietary patterns in adults from an Eastern European country and the presence of obesity.

Significance Testing and Multivariate Analysis of Datasets from Surface Plasmon Resonance and Surface Acoustic Wave Biosensors: Prediction and Assay Validation for Surface Binding of Large Analytes

In this study, we performed uni- and multivariate data analysis on the extended binding curves of several affinity pairs: immobilized acetylcholinesterase (AChE)/bioconjugates of aflatoxin B₁(AFB₁) and immobilized anti-AFB₁ monoclonal antibody/AFB₁-protein carriers. The binding curves were recorded on three mass sensitive cells operating in batch configurations: one commercial surface plasmon resonance (SPR) sensor and two custom-made Love wave surface-acoustic wave (LW-SAW) sensors. We obtained 3D plots depicting the time-evolution of the sensor response as a function of analyte concentration using real-time SPR binding sensograms. These "calibration" surfaces exploited the transient periods of the extended kinetic curves, prior to equilibrium, creating a "fingerprint" for each analyte, in considerably shortened time frames compared to the conventional 2D calibration plots. The custom-made SAW sensors operating in different experimental conditions allowed the detection of AFB₁-protein carrier in the nanomolar range. Subsequent statistical significance tests were performed on unpaired data sets to validate the custom-made LW-SAW sensors.

CARDIOVASCULAR RISK ASSESSMENT IN THE ADULT (AGED 40-79 YEARS) ROMANIAN POPULATION

Atherosclerotic Cardiovascular Diseases are the leading cause of death worldwide.

Aim

To estimate the prevalence of cardiovascular risk (CVR) categories in the adult population (aged 40-79 years) of Romania.

Design

The present study was part of the epidemiological, cross-sectional PREDATORR study (PREvalence of DiAbeTes mellitus, prediabetes, overweight, Obesity, dyslipidemia, hyperuricemia and chronic kidney disease in Romania).

Subjects and Methods

Exclusion criteria: age <40/or>79 years old and diagnosis of ischemic vascular disease. The CVR was evaluated using charts developed by the World Health Organization/ International Society of Hypertension (WHO/ISH) available for Europe B (epidemiological sub-region where Romania was included). The CVR was divided into 5 categories: <10%, 10-20%, 20-30%, 30-40%, > 40%.

Results

A total of 1631 subjects (57.0±10.7 years, 45.1% males) were included in the present study.The age and sex-adjusted prevalence of CVR >40% was 2.9% (95%CI 2.8-3.1%), CVR 30-40% was 1.85% (95%CI 1.8-1.9%), CVR 20-30% was 5.8% (95%CI 5.6-6.0%) and 13.0% (95%CI 12.8-13.3%) of the adult Romanian population has a 10-20% CVR, these CVR categories being more frequent in male and older age. Diabetes, overweight/obesity and smoking were associated with high CVR categories.

Conclusion

Romania is one of the countries with high CVR, requiring CVD prevention measures.

Peptide-based biosensors: From self-assembled interfaces to molecular probes in electrochemical assays

Redox-tagged peptides have emerged as functional materials with multiple applications in the area of sensing and biosensing applications due to their high stability, excellent redox properties and versatility of biomolecular interactions. They allow direct observation of molecular interactions in a wide range of affinity and enzymatic assays and act as electron mediators. Short helical peptides possess the ability to self-assemble in specific configurations with the possibility to develop in highly-ordered, stable 1D, 2D and 3D architectures in a hierarchical controlled manner. We provide here a brief overview of the electrochemical techniques available to study the electron transfer in peptide films with particular interest in developing biosensors with immobilized peptide motifs, for biological and clinical applications.

Unprecedented Catalytic Wet Oxidation of Glucose to Succinic Acid Induced by the Addition of n-Butylamine to a Ru(III) Catalyst

A new pathway for the catalytic wet oxidation (CWO) of glucose is described. Employing a cationic Ru@MNP catalyst, succinic acid is obtained in unprecedently high yield (87.5 %) for a >99.9 % conversion of glucose, most probably through a free radical mechanism combined with catalytic didehydroxylation of vicinal diols and hydrogenation of the resulted unsaturated intermediate.

Prevalence of overweight/obesity, abdominal obesity and metabolic syndrome and atypical cardiometabolic phenotypes in the adult Romanian population: PREDATORR study

PURPOSE

The objectives were to assess the prevalence of overweight/obesity, abdominal obesity and metabolic syndrome (MetS), and to evaluate the characteristics of the metabolically unhealthy lean (MUHL) and metabolically healthy overweight/obese (MHO) phenotypes in a Romanian population-based sample from the PREDATORR study.

METHODS

PREDATORR was an epidemiological study with a stratified, cross-sectional, cluster random sampling design. Participants were classified into four cardiometabolic phenotypes based on the BMI, the cut-off value being 25 kg/m(2), and the presence of MetS (defined according to the Harmonization definition 2009): MUHL, MHO, metabolically healthy lean (MHL) and metabolically unhealthy overweight/obese (MUHO).

RESULTS

Overall, 2681 subjects aged 20-79 years were included in the analysis. The overall age and sex-adjusted prevalence of obesity was 31.90 %, overweight was 34.7 %, abdominal obesity was 73.90 % and MetS was 38.50 %. The age- and sex-adjusted prevalence of MHO phenotype was 31.60 %, while MUHL phenotype prevalence was 3.90 %. MUHL and MHO participants had a cardiometabolic profile, kidney function and CVD risk intermediary between MHL and MUHO. MUHL had higher odds of being associated with CVD risk (OR 5.8; p < 0.001), abdominal obesity, prediabetes, diabetes, hypertriglyceridemia and hypo-HDL cholesterolemia than MHL, while MHO phenotype was associated with hypo-HDL cholesterolemia (OR 3.1; p = 0.002), prediabetes (OR 2.9; p < 0.001) and abdominal obesity.

CONCLUSIONS

PREDATORR study showed a high prevalence of obesity/overweight, abdominal obesity and MetS in the adult Romanian population, and their association with kidney function and several cardiometabolic factors.

UPDATING THE CONCEPT OF METABOLICALLY HEALTHY OBESITY

Obesity is a well-recognized risk factor for type 2 diabetes, cardiovascular disease, and several types of cancer. However, a proportion of the obese individuals display a significantly lower risk for metabolic complications than expected for their degree of body mass index, and this subtype of obesity was described as "metabolically healthy obesity" (MHO). No universally accepted criteria for the diagnosis of MHO exists and the prevalence of this subtype of obesity varies largely according to criteria used. Broadly, MHO is characterized by a lower amount of visceral fat, a more favorable inflammatory profile, and less insulin resistance as compared to the metabolically unhealthy obesity. Currently, controversies exist regarding the risk of cardiovascular events and all-cause mortality associated with MHO as compared to metabolically-healthy non-obese individuals. Further research is needed in order to identify the MHO phenotype and if MHO is truly healthy for a long period of time or if it is a transient state from normal metabolic/normal weight to abnormal metabolic/obese state. This review will discuss the MHO definition criteria; the differences between MHO and metabolically unhealthy obesity; the possible underlying mechanisms and clinical implications of MHO.

EATING PATTERNS, PHYSICAL ACTIVITY AND THEIR ASSOCIATION WITH DEMOGRAPHIC FACTORS IN THE POPULATION INCLUDED IN THE OBESITY STUDY IN ROMANIA (ORO STUDY)

Context

Four major modifiable behavioral risk factors are considered responsible for the current burden of the non-communicable diseases: tobacco use, physical inactivity, unhealthy diet and excessive alcohol consumption. Limited data on the lifestyle habits in Romanian population is currently available.

Objective

To assess the eating patterns and physical activity habits and other lifestyle components in various age groups in the population included in the ORO study.

Design

ORO was a cross-sectional, epidemiologic, multicenter non-interventional study conducted from January 2014 until August 2014 in 8 study centers spread in the main historical regions of Romania.

Results

Eating 3 meals/day every day was more frequently reported in the 60-79 years and ≥ 80 years age groups (53.0% and 51.7%) than in the 18-39 years and 40-59 years age groups (26.8% and 35.8%), p <0.001. The frequency of eating breakfast every day increased with age from 43.5% in the youngest age group to 79.3% in the oldest one (p <0.001). Intense and moderate leisure-time physical activity was more frequent among participants in the 18- 39 years age group. Leisure time physical activities were associated with younger age groups, male sex, rural area, higher educational level and non-smoking status. Regular breakfast and regular consumption of 3 meals/day was associated with older age group, male sex and non-smoking status.

Conclusions

Our analysis showed a high frequency of unhealthy lifestyle habits among the younger age groups as compared to the older ones, with the highest frequency of these unhealthy behavior reported in the 18-39 years age group.

Classification of red wines using suitable markers coupled with multivariate statistic analysis

Methodologies for chemometric classification of five authentic red wine varieties from Murfatlar wine center, Romania, young and aged are reported. The discriminant analysis based on several anthocyanins, organic acids, (13)C/(12)C, (18)O/(16)O and D/H isotopic ratios, (1)H and (13)C NMR fingerprints revealed a very satisfactory categorization of the wines, both in terms of variety and vintage, thus illustrating the validity of selected variables for wine authentication purposes. LDA applied to the combined data shows 85.7% classification of wines according to grape variety and 71.1% classification of wines according to vintage year, including a control wine set for each categorization, thus allowing an accurate interpretation of the data. Thereby, anthocyanins, certain anthocyanin ratios, oxalic, shikimic, lactic, citric and succinic acids, sugars like glucose, amino acids like histidine, leucine, isoleucine and alanine, and also 2,3-butanediol, methanol, glycerol and isotopic variables were significant for classification of wines.

A modular electrochemical peptide-based sensor for antibody detection

We report a modular electrochemical peptide-based sensor targeting the anti-deamidated gliadin peptide (DGP) antibody. A recognition peptide, here DGP, is grafted onto a supporting peptide bearing a redox label. The fabricated peptide-based sensor supports the detection of the target antibody (anti-DGP antibody) in the nanomolar range.

Predisposing factors for neuropathic ulcerations in patients with diabetes

OBJECTIVE

To assess the risk factors the precipitates ulcerations.

MATERIAL AND METHODS

In this study a group of 100 patients were selected from November 2007 till October 2008 who were coming for treatment at the Diabetes center of Cluj Napoca, Romania for treatment. 50 cases were patients with ulcerations and 50 without any ulceration.

RESULTS

Most important results were: (Age, sex type, biological parameters like HDL, total cholesterol, creatinine ESR, polyneuropathy, arteriopathy, diabetic foot type, diabetes duration). We obtained these results using different statical methods.

CONCLUSION

Ulcerations in diabetic neuropathy are caused by a whole combination of several factors which should be monitored by a meticulous examination and careful follow up of diabetic patients. This in turn will be beneficiary for patients as well as economically interesting reduce the amount of money which is used to treat ulcerations.

Acetylcholinesterase biosensor for carbamate drugs based on tetrathiafulvalene-tetracyanoquinodimethane/ionic liquid conductive gels

A highly sensitive acetylcholinesterase biosensor was developed for detection of carbamate drugs based on TTF-TCNQ-ionic liquid gel thiocholine sensor. The TTF-TCNQ-ionic/ionic liquid gel was characterized by FT-IR and scanning electron microscopy. The electrocatalytic behavior of TTF-TCNQ-ionic liquid gels toward oxidation of thiocholine was thoroughly investigated. 1-Ethyl-3-methylimidazolium tetracyanoborate gel based sensor allowed amperometric detection of thiocholine at +400 mV vs. Ag/AgCl with a high sensitivity of 55.9±1.2 μA mM(-1)cm(-2) and a low detection limit equal to 7.6 μM. The catalytic rate constant and diffusion constant of thiocholine were estimated from chronoamperometric data. The proposed biosensor based on AChE immobilized in sol-gel matrix was used for the detection of two carbamate therapeutic drugs. Very low detection limits of 26 pM eserine and 0.3 nM neostigmine were achieved. The analysis of spiked tap water proved the biosensor capability to be used as a screening method for detection of carbamate drugs in wastewaters.

Phase II study of erlotinib plus gemcitabine in first-line treatment of poor prognosis, advanced non-small cell lung cancer patients

PURPOSE

The purpose of the present trial was to investigate whether clinical benefit can be obtained by concurrent administration of erlotinib with gemcitabine as first-line treatment in patients with advanced non-small cell lung cancer (NSCLC) and ECOG performance status (PS) 2.

METHODS

Included were chemotherapy-naive patients with histologically/cytologically documented unresectable advanced and/or metastatic (stage IIIB/IV) NSCLC and ECOG PS 2. In this phase II, single-arm study, all patients received first-line gemcitabine plus erlotinib for 6 cycles or until disease progression, unacceptable toxicity or patient withdrawal due to any reason. The primary study objectives were the evaluation of disease response and the time to progression. Secondary objectives included evaluation of overall survival and the safety profile of gemcitabine plus erlotinib.

RESULTS

Nineteen eligible patients were studied. The overall response rate (complete response/CR and partial response7sol;PR) was 15.8% and the clinical benefit rate (CR+PR+stable disease sol;SD) 36.84%.The median overall survival for the whole study group was 39 weeks (95% CI 27-51) and the median time to disease progression for 19 evaluable patients was 15 weeks (95% CI 7-36). The safety profile of the combination was acceptable with only 2 serious adverse events.

CONCLUSION

Taking into account similar published clinical studies we conclude that gemcitabine plus erlotinib achieve superior response rate and comparable overall survival with acceptable toxicity compared to monochemotherapy with gemcitabine. This combination represents a treatment option for patients with advanced NSCLC and ECOG PS 2.

Synergistic effect of mediator-carbon nanotube composites for dehydrogenases and peroxidases based biosensors

Very sensitive, low cost and reliable NADH and H(2)O(2) sensors were realised and used for development of enzyme based biosensors. The active surface of the electrodes was modified with a nanocomposite obtained by modification of SWNT with a proper mediator: Meldola Blue (for NADH) and Prussian Blue (for H(2)O(2)). Low applied potential of -50 mV vs. Ag/AgCl reference electrode proved the synergistic effect of nanocomposite materials towards NADH and H(2)O(2) detection. Biosensors for malic acid and alkylphenols have been developed, using mediator-functionalized-SWNT-based electrodes and two different classes of enzymes: NAD(+)-dependent dehydrogenases and peroxidases. Immobilization of the enzymes was realised using a series of different procedures - adsorption, Nafion membrane, sol-gel and glutaraldehyde, in order to find the best configuration for a good operational stability. A higher sensitivity comparing with other reported biosensors of about 12.41 mA/M.cm(2) was obtained for l-malic acid biosensor with enzyme immobilised in Nafion membrane. Phenol, 4-t-octylphenol and 4-n-nonylphenol were used as standard compounds for HRP based biosensor. Fast biosensor response and comparable detection limit with HPLC methods were achieved.

Amperometric Low-Potential Detection of Malic Acid Using Single-Wall Carbon Nanotubes Based Electrodes

The electrocatalytical property of single-wall carbon nanotube (SWNT)modified electrode toward NADH detection was explored by cyclic voltammetry andamperometry techniques. The experimental results show that SWNT decrease theovervoltage required for oxidation of NADH (to 300 mV vs. Ag/AgCl) and this propertymake them suitable for dehydrogenases based biosensors. The behavior of the SWNTmodified biosensor for L-malic acid was studied as an example for dehydrogenasesbiosensor. The amperometric measurements indicate that malate dehydrogenase (MDH)can be strongly adsorbed on the surface of the SWNT-modified electrode to form anapproximate monolayer film. Enzyme immobilization in Nafion membrane can increasethe biosensor stability. A linear calibration curve was obtained for L-malic acidconcentrations between 0.2 and 1mM.

Biosensors based on screen-printing technology, and their applications in environmental and food analysis

This review summarizes scientific research activity on biosensors, especially screen-printed, electrode-based biosensors. The basic configurations of biosensors based on screen-printing technology are discussed and different procedures for immobilization of the biorecognition component are reviewed. Theoretical aspects are exemplified by practical environmental and food-analysis applications of screen-printed, electrode-based biosensors.

On-line assay of the S-enantiomers of enalapril, ramipril and pentopril using a sequential injection analysis/amperometric biosensor system

A sequential injection analysis/amperometric biosensor system is proposed for the enantioselective analysis of the S-enantiomer of enalapril, ramipril and pentopril. The amperometric biosensor used as detector in the sequential injection analysis was designed by immobilization of l-amino acid oxidase in carbon paste. The proposed SIA system can be utilized reliably for the enantioanalysis of the S-enantiomer from the raw materials as well as from their pharmaceutical formulations, with a rate of 75 samples per hour and R.S.D. values better than 0.1% (n = 10).