Electronically addressable nanomechanical switching of i-motif DNA origami assembled on basal plane HOPG

Here, a pH-induced nanomechanical switching of i-motif structures incorporated into DNA origami bound onto cysteamine-modified basal plane HOPG was electronically addressed, demonstrating for the first time the electrochemical read-out of the nanomechanics of DNA origami.

Trypanosoma cruzi infection in Mepraia gajardoi and Mepraia spinolai: the effect of feeding nymphs from the field

We evaluated Trypanosoma cruzi infection rates by means of minicircle DNA-based polymerase chain reactions (PCRs) in 70 starved Mepraia gajardoi from northern Chile and 65 M. spinolai from central Chile after feeding. Immediately after collection in the field, 20% of M. gajardoi were found infected; after feeding, 67% of the uninfected were infected. One group of M. spinolai seemed to be completely uninfected, but after the first and second feedings, 62% and 59% were positive, respectively.

Aerobic co-treatment of landfill leachate and domestic wastewater - are slowly biodegradable organics removed or simply diluted?

This study investigated the co-treatment of landfill leachate/domestic wastewater in bench-scale activated sludge (AS) reactors to determine whether the slowly biodegradable organic matter (SBOM) was removed rather than diluted. The AS reactors were loaded with mixtures of raw leachate and leachate that was pretreated by air stripping. The tested volumetric ratios were 0%, 0.2%, 2% and 5%. For all of the tested conditions, the reactors performed better when pretreated leachate was used rather than raw leachate, and the best volumetric ratio was 2%. The following removals were obtained: 97% for the biochemical oxygen demand (BOD5,20), 79% for total suspended solids, 77% for dissolved organic carbon and 84% for soluble chemical oxygen demand. Most of the pretreated leachate SBOM (65%) was removed rather than diluted or adsorbed into the sludge, as confirmed by Fourier transform infrared (FTIR) spectroscopy analyses.

Trypanosoma cruzi genotypes in Mepraia gajardoi from wild ecotopes in northern Chile

We evaluated Trypanosoma cruzi infection in 397 wild Mepraia gajardoi specimens from five coastal localities in northern Chile by detection of minicircle DNA by polymerase chain reaction. The wild capture sites were classified into two ecotopes: a fully wild ecotope (ecotope 1) and a wild ecotope near human dwellings (ecotope 2). Infection rates varied between 11% and 27%. Minicircle hybridization assays showed that T. cruzi lineages Tc II and Tc VI were commonly detected in ecotope 1 and ecotope 2, respectively. These results are discussed in the context of insect proximity to human dwellings, the alimentary profile of Mepraia sp., T. cruzi lineages detected in the past in the same disease-endemic area circulating in humans, and Triatoma infestans.

Inflammatory muscle pain is dependent on the activation of kinin B₁ and B₂ receptors and intracellular kinase pathways

BACKGROUND AND PURPOSE

B(1) and B(2) kinin receptors are involved in pain transmission but they may have different roles in the muscle pain induced by intense exercise or inflammation. We investigated the contribution of each of these receptors, and the intracellular pathways involved, in the initial development and maintenance of the muscle pain associated with inflammation-induced tissue damage.

EXPERIMENTAL APPROACH

Mechanical hyperalgesia was measured using the Randall-Selitto apparatus after injecting 5% formalin solution into the gastrocnemius muscle in mice treated with selective antagonists for B(1) or B(2) receptors. The expression of kinin receptors and cytokines and the activation of intracellular kinases were monitored by real-time PCR and immunohistochemistry.

KEY RESULTS

The i.m. injection of formalin induced an overexpression of B(1) and B(2) receptors. This overexpression was associated with the mechanical hyperalgesia induced by formalin because treatment with B(1) receptor antagonists (des-Arg(9) [Leu(8)]-BK, DALBK, and SSR240612) or B(2) receptor antagonists (HOE 140 and FR173657) prevented the hyperalgesia. Formalin increased myeloperoxidase activity, and up-regulated TNF-α, IL-1β and IL-6 in gastrocnemius. Myeloperoxidase activity and TNF-α mRNA expression were inhibited by either DALBK or HOE 140, whereas IL-6 was inhibited only by HOE 140. The hyperalgesia induced by i.m. formalin was dependent on the activation of intracellular MAPKs p38, JNK and PKC.

CONCLUSIONS AND IMPLICATIONS

Inflammatory muscle pain involves a cascade of events that is dependent on the activation of PKC, p38 and JNK, and the synthesis of IL-1β, TNF-α and IL-6 associated with the up-regulation of both B(1) and B(2) kinin receptors.

First WHO International Reference Panel containing hepatitis B virus genotypes A-G for assays of the viral DNA

BACKGROUND

WHO International Standards (IS) are provided for the calibration and validation of diagnostic and screening assays, e.g. for hepatitis B virus (HBV). HBV forms numerous subgenotypes and the current IS for HBV DNA reflects subgenotype A2.

OBJECTIVE

A reference panel with the most prevalent subgenotypes should facilitate evaluation of genotype-specific detection efficiencies.

STUDY DESIGN

215 HBV positive plasma samples collected worldwide were characterized for HBV markers and sequenced. Fifteen subgenotype A1, A2, B2, B4, C2, D1, D3, E, F2 and G samples were selected for the panel. The lyophilized samples were tested in parallel with the IS in an international collaborative study with 16 laboratories using 13 different nucleic acid amplification techniques (NATs).

RESULTS

Eight of 13 NAT had a HBV DNA detection efficiency which was independent of the genotype and consistent with the IS, while with five assays, certain deviations were noted, particularly with genotype F which was under quantitated or even missed by three assays. The panel was accepted by the WHO as the "1st WHO International Reference Panel for HBV Genotypes for HBV NAT-Based Assays".

CONCLUSIONS

The evaluation of HBV DNA assays should include many different genotypes. The WHO Reference Panel is universally available for manufacturers of HBV DNA assays, diagnostic laboratories and control authorities to facilitate standardized validation of HBV genotype specific detection efficiency of both diagnostic (quantitative and qualitative) and screening NAT assays.

A new laser Doppler flowmeter prototype for depth dependent monitoring of skin microcirculation

Laser Doppler flowmetry (LDF) is now commonly used in clinical research to monitor microvascular blood flow. However, the dependence of the LDF signal on the microvascular architecture is still unknown. That is why we propose a new laser Doppler flowmeter for depth dependent monitoring of skin microvascular perfusion. This new laser Doppler flowmeter combines for the first time, in a device, several wavelengths and different spaced detection optical fibres. The calibration of the new apparatus is herein presented together with in vivo validation. Two in vivo validation tests are performed. In the first test, signals collected in the ventral side of the forearm are analyzed; in the second test, signals collected in the ventral side of the forearm are compared with signals collected in the hand palm. There are good indicators that show that different wavelengths and fibre distances probe different skin perfusion layers. However, multiple scattering may affect the results, namely the ones obtained with the larger fibre distance. To clearly understand the wavelength effect in LDF measurements, other tests have to be performed.

Trypanosoma cruzi genotypes of insect vectors and patients with Chagas of Chile studied by means of cytochrome b gene sequencing, minicircle hybridization, and nuclear gene polymorphisms

Fifty-six Trypanosoma cruzi stocks from Chile and neighboring countries and different hosts, humans, and Triatoma infestans and Mepraia sp., vectors of domiciliary and natural environments were characterized by using three molecular markers. These were cytochrome b (Cyt b) gene sequencing, minicircle DNA blotting, and hybridization with five genotype-specific DNA probes and nuclear analysis of 1f8 and gp72 by polymerase chain reaction-restriction fragment length polymorphism. The results with all three molecular markers are concordant, with minor limitations, grouping T. cruzi stocks into four discrete typing units (DTUs) (TcI, TcII, TcV, and TcVI). TcI and TcII stocks were heterogeneous. TcI and TcII stocks were clustered in two main subgroups determined by Cyt b gene sequencing and minicircle hybridization. However, TcV and TcVI stocks were homogeneous and not differentiated by Cyt b gene sequencing or minicircle DNA hybridization. The discriminatory power and limitations of the molecular markers are discussed, as well as the distribution of the four DTUs in the domiciliary and sylvatic transmission cycles of Chile and the limitations of each marker for molecular epidemiological studies performed with T. cruzi stocks rather than the analysis of direct T. cruzi samples from natural hosts.

[Laparoscopic simple prostatectomy (adenomectomy): experience in 59 consecutive patients]

OBJECTIVE

Laparoscopic adenomectomy 150 is a minimally invasive alternative to open surgery in large prostates. Our aim is to discuss our series of 59 patients treated by means of laparoscopic adenomectomy with precise vascular control.

MATERIALS AND METHODS

Between June 2003 and June 2006, a total of 59 patients with a mean age of 65.5 years (51 to 82), underwent laparoscopic extraperitoneal adenomectomy. All the patients had a history of lower urinary tract symptoms (LUTS) and benign prostatic hyperplasia (BPH). The mean International Prostate Symptom Score (IPSS) was 20 points (16-22). The information was collected prospectively in a database. The analysis was performed subsequently.

RESULTS

All 59 adenomas were completely removed laparoscopically without conversion to open surgery. The mean preoperative prostate volume by ultrasound was 108.5 cc (75-150). The average operating time was 123 minutes (90-180). The mean loss of blood was 415 ml (50-1500) and 4 patients (14.8%) required a blood transfusion. Two (7.4%) of the patients presented perioperative complications. The mean hospital stay and the bladder catheterization time were 3.5 (2-7) and 4.2 (3-7) days respectively.

CONCLUSIONS

Laparoscopic extraperitoneal simple prostatectomy is an effective procedure for the treatment of large prostatic adenomas. There seems to be less perioperative morbidity and, in our experience, this technique seems to be feasible and reproducible; however, its learning curve is a complicated matter to deal with.

[Laparoscopic radical cystectomy with extracorporeal creation of a "Y" shaped orthotopic ileal neobladder using non-reabsorbable mechanical suture (Fontana)]

INTRODUCTION

We describe the technique and present the preliminary results of the laparoscopic radical cystectomy technique with the extracorporeal creation of a "y" shaped ileal orthotopic neobladder using non-absorbable mechanical suture (Fontana).

MATERIALS AND METHOD

We describe the technique step by step and we present a series of 15 patients that underwent this surgery between November 2005 and August 2009, with special emphasis on the duration of the surgery, urinary diversion time, intraoperative and postoperative complications, daytime and night time continence and the frequency of postoperative micturition.

RESULTS

The mean follow-up of the series was 24 months (6-32). The mean duration of surgery was 280 (range 210-345) minutes and the mean urinary diversion time was 54.5 (range 40-75) minutes. There were no intraoperative complications and the average hospitalization time was 7 (range 5-15) days. During the follow-up, there were 5 late postoperative complications, 2 cases of urinary infection with good response to antibiotic treatment and 3 uretero-neovesical anastomosis strictures, which were treated with percutaneous balloon dilation, with a good functional result. No lithiasis was found in the neobladder. Complete daytime continence was obtained in 13/14 patients (92.9%) and complete night time continence in 6/14 (42.9%). One patient (6.7%) required clean intermittent self-catheterization as the patient did not micturate spontaneously.

CONCLUSIONS

The creation of a "Y" shaped ileal orthotopic neobladder using non-absorbable mechanical suture is a feasible, fast and safe technique and it provides promising functional results. Further follow-up is required to determine its long-term results.

Temporal variation of Trypanosoma cruzi infection in native mammals in Chile

In the present study, we compared Trypanosoma cruzi infection in four native mammals from a hyperendemic area of Chagas disease in Chile for two different periods to assess the occurrence of interannual variation (1999-2000 vs. 2005-2006). Parasite detection in mammals is performed by polymerase chain reaction assays and confirmed by Southern blot analysis and hybridization test with a universal probe. Results showed significant differences in the levels of T. cruzi infection between the compared periods. We suggest that the major El Niño event occurred in 1997-1998, a large-scale global climatic fluctuation, could be indirectly explaining the extremely high T. cruzi infection in 1999-2000 by means of a time-lag response of the wild transmission cycle of Chagas disease in semiarid Chile after the irruption of small rodent populations.