Disposable sensors for rapid screening of mutated genes

A screening method for rapid detection of gene mutations directly in polymerase chain reaction (PCR) of genomic DNA is described. The method involves the development of a disposable screen-printed gold electrode modified with a thiolated capture probe directly obtained from denaturated PCR genomic DNA, which recognizes (by hybridization) its fully complementary sequence (wild type), giving a signal, whereas no signal is obtained for single-mismatched target (mutant). The detection of the hybridization event is achieved by changes in the metal redox center electroactivity of the complex [Ru(NH(3))(5) L](2+), where L is [3-(2-phenanthren-9-yl-vinyl)-pyridine], at -0.200 V. This complex binds to double-stranded DNA in a very selective form. The method allows discrimination between the wild type and the mutant of gene MRP3 directly in large PCR amplicons extracted from blood cells, without the need to use either synthetic probes or labeled targets. The mutation involves the presence of a single-nucleotide polymorphism (SNP) at base 54 of a 145-base-pair sequence from exon 21 of gene MRP3. Since the presence of this SNP might lead to a variety of hereditary liver disorders, its identification in a rapid and easy form may provide novel therapeutic targets for the future. The screening method proposed has excellent signal reproducibility, with a relative standard deviation of 10%. In addition, with the method developed as little as 6.6 ng/muL PCR product can be detected.

Cortical excitability in very mild Alzheimer's disease: a long-term follow-up study

Measurement of motor cortex excitability using paired-pulse transcranial magnetic stimulation (pTMS) has been proposed for the early diagnosis of Alzheimer's disease (AD) and could also be useful for monitoring treatment response and disease progression. However, studies conducted at the pre-dementia stage of AD are scarce, very few long-term data are available, and correlations between cortical excitability and cognitive performance have not been addressed. Eleven patients with mild cognitive impairment (MCI) that converted to AD-related dementia and 12 elderly control subjects were selected for this study. Cognitive assessments and pTMS were conducted at baseline in the two groups and also after 4 and 21 months of treatment with donepezil in the AD group. Non-parametric statistics were used to compare cortical excitability between the two study groups at baseline and to analyse disease course in the AD group. Correlation analysis was performed to investigate associations between cortical excitability and cognitive performance. Short-latency intracortical inhibition (SICI) and intracortical facilitation were reduced in AD patients. However, there was high inter-individual variability, and statistical significance was only attained at a 2-ms interstimulus interval (ISI). A trend towards recovery of 2-ms SICI was observed after treatment with donepezil. Baseline cortical excitability at 300 ms was associated with better cognitive performance in AD patients. Although the present results do not support a role for pTMS in the early diagnosis of late-onset AD, a potential role in prediction of treatment response and understanding of disease mechanisms emerged.

Cefditoren versus ceftazidime in inducer-substrate combinations for the evaluation of AmpC production in a disc approximation test

OBJECTIVE

To evaluate cefditoren in inducer-substrate combinations to screen for AmpC induction.

METHODS

100 clinical isolates (25 P. aeruginosa, 25 E. cloacae, 14 M. morganii, 13 S. marcescens, 12 C. freundii, 7 P. rettgeri, and 4 E. aerogenes) were tested by the Kirby-Bauer disc approximation method using cefditoren and ceftazidime discs as substrates, and cefditoren and imipenem discs as inducers.

RESULTS

None of the strains showed induction of AmpC with cefditoren-ceftazidime as inducer-substrate combination. Imipenem-cefditoren as inducer-substrate combination was not useful for evaluating strains of P. aeruginosa since no inhibition zones surrounding the cefditoren disc were found. Among evaluable enterobacteria (those showing substrate inhibition zone), inducible Amp C was detected in 48 out of 63 (76.2%) with cefditoren, and in 33 out of 68 (48.5%) isolates with ceftazidime as substrate. Significantly (p=0.013) higher number of AmpC producers were detected with cefditoren versus ceftazidime (76.2% vs. 48.5%), due to the differences found for E. cloacae (72.8% vs. 21.7%; p=0.0009) and S. marcescens (100% vs. 54.5%; p=0.03). Higher mean reductions of diameters around substrate discs were found for cefditoren (4.17 mm) vs. ceftazidime (3.79 mm), reaching statistical significance (p<0.05) for indol-positive proteae: M. morganii (5.32 mm vs. 3.92 mm) and P. rettgeri (3.47 mm vs. 2.64 mm).

CONCLUSION

Cefditoren showed no induction capability, and when used as substrate (with imipenem as inducer) it offered detection rates of AmpC inducible enterobacteria higher than the imipenem-ceftazidime combination, mainly for Enterobacter spp. and Serratia spp., with higher diameter reductions for indol-positive proteae.

In vitro interference of beta-lactams with biofilm development by prevalent community respiratory tract isolates

Interference of cefditoren (CDN) and amoxicillin/clavulanic acid (AMC) with biofilm production was studied using 11 Streptococcus pneumoniae isolates with minimum inhibitory concentrations (MICs) ranging from 0.015microg/mL to 0.5microg/mL for CDN and from 0.06microg/mL to 2microg/mL for AMC (except for one isolate with an AMC MIC of 8microg/mL) and 5 Haemophilus influenzae isolates with MICs of 0.03-0.06microg/mL for CDN and 0.5-16microg/mL for AMC. Slime production was assessed in antibiotic-free medium and with 0.03microg/mL CDN or 1/0.5microg/mL AMC by measuring the optical density at 450nm (OD(450)). Significantly lower mean OD(450) values were obtained for S. pneumoniae with antibiotics compared with controls (CDN, 0.088 vs. 0.118, P=0.003; and AMC, 0.095 vs. 0.112, P=0.003), with significant correlation between both antibiotics (r=0.752; P=0.008). Percent reduction in OD(450) values was higher for CDN compared with AMC (24.02% vs. 15.92%; P=0.008). For H. influenzae, significantly lower mean OD(450) values were obtained with CDN compared with controls (0.083 vs. 0.096; P=0.043) but not with AMC (0.086 vs. 0.095; P=0.08). Comparing percent reductions in S. pneumoniae versus H. influenzae for each antibiotic, no differences were found for AMC (15.92% vs. 9.40%; P=0.36), with a tendency for CDN (24.02% vs. 13.79%; P=0.069). Different beta-lactams may have different capabilities of interfering with S. pneumoniae biofilm development when tested under the same experimental conditions.

Analysis of the impact of a new electro-chemical activation system for potable water disinfection on the Legionella pneumophila isolation rate in a Spanish hospital

In a field study comparing isolation rates pre- and post-installation of an electro-chemical activation system for Legionella pneumophila disinfection of potable hot water in a Spanish hospital, a total of 250 tap samples pre-installation and 113 post-installation were collected. Chlorine levels were higher ( p < 0.001) post-installation (0.55 ± 0.41 vs. 1.19 ± 0.44 ppm). Of 38.0% (138/363) samples positive for L. pneumophila, 111 (80.4%) were serogroups 2—14. Post-installation, the isolation rate was lower (46.8% vs. 18.6%; p < 0.001, odds ratio (OR) 0.26, 95% confidence interval (CI) 0.15—0.44) due to significant ( p < 0.001; OR 0.25, 95% CI 0.14—0.45) reduction in L. pneumophila serogroups 2—14 from 38.4% to 13.3%. Post-installation, isolation rates were lower in spring (44.4% vs. 0.0%; p < 0.001), summer (80.0% vs. 25.0%; p = 0.003) and autumn (72.0% vs. 28.9%; p = 0.018), but not in winter (18.5% vs. 11.8%; p = 0.688). The seasonal wave constructed with pre-installation data significantly decreased post-installation by decreasing isolation rates in summer and autumn to rates similar to those found in winter pre-installation.

Bactericidal activity of daptomycin versus vancomycin in the presence of human albumin against vancomycin-susceptible but tolerant methicillin-resistant Staphylococcus aureus (MRSA) with daptomycin minimum inhibitory concentrations of 1-2microg/mL

This study explored the influence of vancomycin tolerance and protein binding on the bactericidal activity of vancomycin versus daptomycin (protein binding 36.9% vs. 91.7%, respectively) against four vancomycin-tolerant methicillin-resistant Staphylococcus aureus (MRSA) [minimum inhibitory concentration/minimum bactericidal concentration (MIC/MBC)=0.5/16, 1/32, 2/32 and 1/32microg/mL for vancomycin and 1/1, 1/2, 2/2 and 2/4microg/mL for daptomycin]. Killing curves were performed with vancomycin/daptomycin concentrations equal to serum peak concentrations (C(max)) (65.70/98.60microg/mL) and trough concentrations (C(min)) (7.90/9.13microg/mL) in the presence and absence of a physiological human albumin concentration (4g/dL), controlled with curves with the theoretical free drug fraction of vancomycin/daptomycin C(max) (41.45/8.18microg/mL) and C(min) (4.98/0.76microg/mL). Vancomycin C(max) and C(min) concentrations, regardless of the media, showed a bacteriostatic profile not reaching a reduction of 99% or 99.9% of the initial inocula during the 24-h experimental time period. Daptomycin antibacterial profiles significantly differed when testing C(max) and C(min). C(max) was rapidly bactericidal (< or =4h) with >5 log(10) reduction in the initial inocula for all strains, regardless of the presence or not of albumin or the use of concentrations similar to free C(max). C(min) exhibited similar final colony counts at 0h and 24h in curves with albumin, but with >3 log colony-forming units (CFU)/mL reduction at < or =4h for strains with an MIC of 1microg/mL and ca. 2 logCFU/mL reduction at < or =6h for strains with an MIC of 2microg/mL. This activity was significantly higher than the activity of the free C(min) fraction. The results of this study reinforce the idea that pharmacodynamics using concentrations calculated using reported protein binding are unreliable. Daptomycin exhibited rapid antibacterial activity against vancomycin-tolerant MRSA isolates even against those with high daptomycin MICs in the presence of physiological albumin concentrations.

Safety profile of cefditoren. A pooled analysis of data from clinical trials in community-acquired respiratory tract infections

INTRODUCTION

A high number of individuals in the population are exposed to antibiotics for the treatment of respiratory tract infections. It is important to review the adverse events profile related to antibiotic exposure during the clinical development of drugs that are or have been recently included in the therapeutic armamentarium.

MATERIAL AND METHODS

Safety data from all 13 clinical trials of cefditoren on community acquired respiratory infections were reviewed. Safety population was defined as all randomized patients with at least one dose intake. Adverse events considered by investigators as related during antibiotic exposure were considered.

RESULTS

The overall safety population consisted in 4,592 patients for cefditoren and 2,784 for comparators. Overall reported diarrhoea related to cefditoren administration was significantly higher (p < or = 0.001) than comparators (9.9% vs 6.9%) due to the significant difference in the pooled pharyngotonsillitis studies (8.3% vs 3.2%), while no significant differences in others pathologies were found, with 9.4% (with cefditoren) vs 10.3% (with comparators) in the case of community-acquired pneumonia (CAP). Dyspepsia and abdominal pain were reported as adverse events in < 2.7% patients regardless the treated disease. In females population lower related vaginosis rate was found in cefditoren vs comparators, mainly due to differences among patients treated for sinusitis (4.5% vs 8.1%) and CAP (2.3% vs 5.5%) although differences were not significant (p = 0.017 and p = 0.008, respectively).

CONCLUSION

This study analysing reported adverse events from clinical trials showed an adverse events profile of cefditoren similar to those of standard antibiotics used in the treatment of respiratory tract infections.

Inflammation and liver cancer: new molecular links

A connection between inflammation and cancer has been long suspected. Epidemiological studies have established that many tumors occur in association with chronic infectious diseases, and it is also known that persistent inflammation in the absence of infections increases the risk and accelerates the development of cancer. One clear example of inflammation-related cancer is hepatocellular carcinoma (HCC). HCC is a type tumor that slowly unfolds on a background of chronic inflammation mainly triggered by exposure to infectious agents (hepatotropic viruses) or to toxic compounds (ethanol). The molecular links that connect inflammation and cancer are not completely known, but evidences gathered over the past few years are beginning to define the precise mechanisms. In this article we review the most compelling evidences on the role of transcription factors such as NF-kappaB and STAT3, cytokines like IL-6 and IL-1alpha, ligands of the EGF receptor and other inflammatory mediators in cancer development, with special emphasis in HCC. The molecular dissection of the pathways connecting the inflammatory reaction and neoplasia will pave the way for better therapies to treat cancers.

Management in the emergency room of patients requiring hospital treatment of community-acquired pneumonia

INTRODUCTION

To identify factors influencing decisions in initial management of community-acquired pneumonia (CAP) admitted to hospital through Emergency departments.

METHODS

Records of CAP adult patients admitted to 24 Spanish hospitals in January-March 2003 were reviewed. Patients sent for ambulatory treatment were excluded.

RESULTS

341 patients (67.0 +/- 24.6 years; 65.3% males) were included; 39% were taking antibiotics at attendance. PSI was (% patients): I-II (19.7%), III (14.7%), and IV-V (65.6%). Comorbidities were: COPD (37.2%), heart disease (24.6%), hypertension (17%), diabetes mellitus (10.8%), and malignancies (10%). Pneumococcal/Legionella urinary antigens were performed in 34.0%/42.2% patients. Fewer (p < or = 0.006) rapid tests were performed in class IV-V (p = 0.001), with higher (p < or = 0.01) pneumococcal positive results in class V. Initial treatment was fluoroquinolone (37.5%), beta-lactam + macrolide (26.4%), beta-lactam (22.9%), macrolide (4.7%), and others (8.5%). Patients referred to Internal Medicine had higher heart disease (p = 0.06) and hypertension (p = 0.001) as comorbidity than those at Short-Stay Units or Pneumology. COPD patients were equally distributed between Internal Medicine and Pneumology, with differences vs. Short-Stay Units.

CONCLUSIONS

Rapid diagnostic tests were underused, maybe due to broad empirical treatments covering drug-resistant pneumococci and L. pneumophila (regardless PSI and comorbidity). Presence of comorbidities or positive results in rapid diagnostic tests seems to influence the medical ward to which the patient is referred to, but not initial treatment.

[Importance of the antimicrobial spectrum and the bacterial resistances in the antibiotic choice for the treatment of pediatric patients with communitary infections]

OBJECTIVE

This study aimed to know the importance of the antimicrobial spectrum and the bacterial resistances for the antibiotic choice in the extrahospitalary pediatric area, at the same time that establish the relationship with others therapeutics parameters.

MATERIAL AND METHODS

Cross-sectional, observational study within the MUSA (Improvement of Use of Antimicrobial Agents in Primary Health Care) Project made by personal interview of 210 pediatrician doctors randomly selected with national representation. This target is included in a bigger universe (855 doctors) representative of the most doctors responsible of the antibiotic prescriptions in the extrahospitalary area (sample error of the 3.3% for a 95% confidence interval and maximum response dispersion: p=q=50). The results of the pediatric study were subjected to a comparative analysis with the results of a similar study made ten years ago and with the global results of the general study. The questionnaire used for the interview had two clearly different parts: in the first part, the questions were open with the objective to get spontaneous answers from the participants; the second part had questions with suggested answers.

RESULTS

Clinical efficacy is the most spontaneously valued issue by the Spanish pediatricians when it comes to choosing an antimicrobial agent; efficacy is followed by tolerance/safety and posology. Antimicrobial spectrum is mentioned by one out of 4-5 pediatricians that have participated in the study (21.9%), while the bacterial resistances are only mentioned by a 3.8%. In a suggested level, clinical efficacy is still the most valued parameter, being identified by 7 out of 10 interviewed with the bacterial eradication. In this case, the antimicrobial spectrum is the following parameter on significance, appearing as a synonym of "activity against specific microorganisms" in 2 out of 3 cases. In relation to his own evaluation, 3 out of 4 pediatricians say they take "a lot" of the bacterial resistances into consideration, who are mostly understood as "global rate" for 5-6 out of 10 interviewed, whether the resistance showed by the pneumococcal is what worried the most to 4 out of 10 of them. This importance given to the bacterial resistances at the second part of the study contrasts with the low consideration showed when it is compared with other parameters and the valoration is treated in a spontaneous way. In relation to a similar study realized on 1997 (Urano Proyect), we observe that clinical efficacy has replaced tolerance/safety as a parameter to bear in mind, probably as a consequence of more experience and confidence with the most important antimicrobial agents in the antibiotic prescriptions in podiatry. On the other hand, the bacterial resistances still being left out on the pediatricians spontaneous consideration, a fact that is shared with the majority of the collectives participating on the general study. The rest of the parameters stay in a similar way.

CONCLUSIONS

Is necessary to emphasize at the importance of bacterial resistances in the antimicrobials rational use on the pediatric patient. As the antimicrobial tolerance profile has been improving in the last ten years, clinical efficacy, understood as "bacterial eradication" has became the most determining parameter when choosing antimicrobial agents.

Deletion of the E3-6.7K/gp19K region reduces the persistence of wild-type adenovirus in a permissive tumor model in Syrian hamsters

A partial deletion of the adenovirus E3 region, comprising the overlapping 6.7K/gp19K genes, has been described for the incorporation of therapeutic genes in 'armed' oncolytic adenoviruses. This deletion allows the insertion of up to 2.5 kb genetic material into the virus and ensures strong expression of transgenes without reducing the replication and cytolytic potency of viruses in vitro. E3-gp19K and 6.7K proteins are involved in avoiding recognition and elimination of infected cells by the host immune system. Therefore, we have studied the effect of this deletion on the replication and transgene expression of the virus in immunocompetent models based on Syrian hamsters. Tumors were established by intrahepatic injection of pancreatic cancer cells with moderate (HaP-T1, HP-1) or low (H2T) permissivity for adenovirus replication. The wild-type human adenovirus 5 (Ad5) or a modified version containing the luciferase gene in the E3-6.7K/gp19K locus (Ad-WTLuc) were injected intratumorally. We found that elimination of Ad-WTLuc was faster than Ad5 in HaP-T1 and HP-1 tumors. In contrast, no differences were observed when the same tumor was established in severely immunocompromised NOD-scid IL2Rgamma(null) mice. In addition, virus-mediated luciferase expression was more stable in these animals. These results suggest that the lack of E3-6.7K/gp19K genes may accelerate the clearance of oncolytic adenoviruses in some immunocompetent tumor models.

Epidermal growth factor receptor ligands in murine models for erythropoietic protoporphyria: potential novel players in the progression of liver injury

Activation of the epidermal growth factor receptor (EGFR) plays an important role in liver regeneration and resistance to acute injury. However its chronic activation participates in the progression of liver disease, including fibrogenesis and malignant transformation. Hepatobiliary disease represents a constant feature in the clinically relevant Fechm1pas/Fechm1pas genetic model of erythropoietic protoporphyria (EPP). Similarly, chronic administration of griseofulvin to mice induces pathological changes similar to those found in patients with EPP-associated liver injury. We investigated the hepatic expression of the EGFR and its seven most relevant ligands in Fechm1pas/Fechm1pas mice bred in three different backgrounds, and in griseofulvin-induced protoporphyria. We observed that the expression of amphiregulin, betacellulin and epiregulin was significantly increased in young EPP mice when compared to aged-matched controls in all genetic backgrounds. The expression of these ligands was also tested in older (11 months) BALB/cJ EPP mice, and it was found to remain induced, while that of the EGFR was downregulated. Griseofulvin feeding also increased the expression of amphiregulin, betacellulin and epiregulin. Interestingly, protoporphyrin accumulation in cultured hepatic AML-12 cells readily elicited the expression of these three EGFR ligands. Our findings suggest that protoporphyrin could directly induce the hepatic expression of EGFR ligands, and that their chronic upregulation might participate in the pathogenesis of EPP-associated liver disease.

Induction of multiepitopic and long-lasting immune responses against tumour antigens by immunization with peptides, DNA and recombinant adenoviruses expressing minigenes

The development of immunization strategies to induce strong and multiepitopic T-cell responses against tumour antigens is needed for anti-tumour immunotherapy. However, a common finding after immunization with complex antigens is the preferential induction of immune responses against immunodominant epitopes. In this study, with the aim of inducing multiepitopic responses against several common tumour antigens, we have designed a minigene construct encoding four human leucocyte antigen (HLA)-A2-restricted epitopes belonging to tumour antigens CEA (CEA-691 and CEA-571), MAGE2 (MAGE2-157) and MAGE3 (MAGE3-112), as well as the universal PADRE epitope recognized by T helper lymphocytes. To optimize the activation of immune responses against these epitopes, we have used different antigen formats (short peptides encompassing individual epitopes and DNA plasmids or adenoviral constructs expressing the minigene) in single or combined immunization schedules. A single immunization with either DNA plasmid or recombinant adenovirus induced a monospecific immune response against the immunodominant epitope CEA-571, whereas immunization with the peptide pool induced responses against all epitopes. Combination of peptide priming followed by a boost with the plasmid and the recombinant adenovirus expressing the minigene induced stronger, multi-specific and long-lasting immune responses, overcoming the immunodominance imposed by the main T-cell epitope. Moreover, these combined immunization strategies were able to induce responses that were able to recognize Mel624 HLA-A2+ tumour cells expressing MAGE2. These results suggest that heterologous immunization strategies combining peptides and DNA or recombinant adenoviruses can be useful to broaden the specificity and enhance the efficacy of subunit vaccines.

[A day in Spanish microbiology. Descriptive study of the activity of the clinical microbiology departments]

INTRODUCTION

The laboratory is an essential part of the work in the Clinical Microbiology Department. This study has aimed to measure the activity of these laboratories.

MATERIAL AND METHODS

A survey was self-administered on the activity occurring during one work day by each hospital in October 2007.

RESULTS

Thirty six hospitals reported 14,076 tests. Serology was the most frequently reported test (30.3%) followed by urine culture (27.8 %), blood tests (13.2 %), respiratory tract samples (8%), feces (7.1%), urethral (5.8%), skin (5.3%) and cerebrospinal fluid (2.6%). According to species, 73.2% of the isolates were bacteria (22.9 % were positive), 8.9% were virus (17% positive), fungi 8.1% (25.2% positive), and 5.5% mycobacterias (5.9% were positive) and parasite 4.5% (12.5% positive). Susceptibility test were performed by automatic methods (62.3%) followed by diffusion test (27.1%) and E-test (9.1%). A total of 5.6% of the susceptibility tests showed in vitro resistance to antibiotics. Fungi were identified in 108 isolates. Candida and Aspergillus were the most frequent genus (85.1% and 8.3%, respectively). Origins of the samples were: lower respiratory tract (32.4 %), genital tract (24.1 %), urine (10.2 %), blood (10.2 %) and skin (10.2 %). Twelve identification techniques were used, the most frequent being the morphological test (54.8%) and biochemical test (39.7%). Broken down by departments, 20.4% were sent from the ICU, 16.7% from surgery, 29.6% from medicine and 18.5% from primary care.

DISCUSSION

Although the workload of the laboratories has been measured in this work, aspects such as specimen manipulation, clinical advice and research were not considered.

Monocyte-derived dendritic cells from HCV-infected patients transduced with an adenovirus expressing NS3 are functional when stimulated with the TLR3 ligand poly(I:C)

Dendritic cells (DC) transfected with an adenovirus encoding hepatitis C virus (HCV) NS3 protein (AdNS3) induce potent antiviral immune responses when used to immunize mice. However, in HCV infected patients, controversial results have been reported regarding the functional properties of monocyte-derived DC (MoDC), a cell population commonly used in DC vaccination protocols. Thus, with the aim of future vaccination studies we decided to characterize MoDC from HCV patients transfected with AdNS3 and stimulated with the TLR3 ligand poly(I:C). Phenotypic and functional properties of these cells were compared with those from MoDC obtained from uninfected individuals. PCR analysis showed that HCV RNA was negative in MoDC from patients after the culture period. Also, phenotypic analysis of these cells showed lower expression of CD80, CD86, and CD40, but similar expression of HLA-DR molecules as compared to MoDC from uninfected individuals. Functional assays of MoDC obtained from patients and controls showed a similar ability to activate allogeneic lymphocytes or to produce IL-12 and IL-10, although lower IFN-alpha levels were produced by cells from HCV patients after poly(I:C) stimulation. Moreover, both groups of MoDC induced similar profiles of IFN-gamma and IL-5 after stimulation of allogeneic T-cells. Finally, migration assays did not reveal any difference in their ability to respond to CCL21 chemokine. In conclusion, MoDC from HCV patients are functional after transduction with AdNS3 and stimulation with poly(I:C). These findings suggest that these cells may be useful for therapeutic vaccination in chronic HCV infection.