Design of a rapid, multiplex, one-pot miRNA assay optimized by label-free analysis.

MicroRNAs are widely studied as circulating biomarkers for early stage diagnosis of several diseases. Detection and quantification of miRNAs is currently performed through complex and time consuming procedures. Herein we demonstrate a rapid, multiplex, one-pot detection method based on two-step amplification of the signal measured by Reflective Phantom Interface (RPI) label-free optical biosensor. We achieved sub-pM quantification of different miRNAs in about 1.5 h, through specific capture with surface DNA probes combined to a 35-fold mass amplification by an antibody targeting DNA-RNA hybrids and polyclonal secondary antibody, all performed without washing steps. The assay is the result of a modelling and optimization of the multi-step process that has been made possible by the RPI characterization of each individual interaction involved.

Label-free detection of DNA single-base mismatches using a simple reflectance-based optical technique.

Rapid and quantitative detection of the binding of nucleic acids to surface-immobilized probes remains a challenge in many biomedical applications. We investigated the hybridization of a set of fully complementary and defected 12-base long DNA oligomers by using the Reflective Phantom Interface (RPI), a recently developed multiplexed label-free detection technique. Based on the simple measurement of reflected light intensity, this technology enables to quantify the hybridization directly as it occurs on the surface with a sensitivity of 10 pg mm(-2). We found a strong effect of single-base mismatches and of their location on hybridization kinetics and equilibrium binding. In line with previous studies, we found that DNA-DNA binding is weaker on a surface than in the bulk. Our data indicate that this effect is a consequence of weak nonspecific binding of the probes to the surface.

Thermoelectric behavior of Ruddlesden-Popper series iridates.

The goal of this work is to study the evolution of thermoelectric transport across the members of the Ruddlesden-Popper series iridates [Formula: see text], where a metal-insulator transition driven by bandwidth change occurs, from the strongly insulating Sr2IrO4 to the metallic non Fermi liquid behavior of SrIrO3. Sr2IrO4 ([Formula: see text]), Sr3Ir2O7 ([Formula: see text]) and SrIrO3 ([Formula: see text]) polycrystals are synthesized at high pressure and characterized by structural, magnetic, electric and thermoelectric transport analyses. We find a complex thermoelectric phenomenology in the three compounds. Thermal diffusion of charge carriers accounts for the Seebeck behavior of Sr2IrO4, whereas additional drag mechanisms come into play in determining the Seebeck temperature dependence of Sr3Ir2O7 and SrIrO3. These findings reveal a close relationship between magnetic, electronic and thermoelectric properties, strong coupling of charge carriers with phonons and spin fluctuations as well as the relevance of multiband description in these compounds.

Field-induced clearing in sphere-sphere and rod-sphere binary mixtures of charged colloidal particles.

Binary mixtures of larger and smaller colloids having charges of equal sign display unusual response to low-frequency electric fields. We show here that the previously reported negative torque acting on rodlike particles when in presence of a sea of smaller particles is accompanied by a field-induced clearing of the suspension. Measurements of transmitted intensity performed on mixtures of large (dilute) and small (semidilute) spherical particles indicate that such a clearing effect is universal and due to an anisotropic E2 -dependent redistribution of the small spheres around the large ones. We interpret this behavior as resulting from O(E2) electro-osmotic flows whose magnitude is greatly enhanced by the presence of the small particles.

Liquid crystal alignment on a chiral surface: interfacial interaction with sheared DNA films.

We explore the alignment of various achiral liquid crystals on films of aligned double-stranded helical DNA. In all cases and both for the nematic and smectic A phases, we find a distinctly chiral interfacial structure, with the mean orientation of the liquid crystal in contact with the DNA-treated surfaces chirally rotated through a substantial angle with respect to the mean DNA orientation. This rotation originates in the chirality of double-stranded DNA and depends on the liquid crystal molecular structure. We discuss the role of dipolar and hydrophobic coupling in determining the observed orientation.

Pilot study of the efficacy and safety of a modified-release magnesium 250 mg tablet (Sincromag) for the treatment of premenstrual syndrome.

BACKGROUND: Magnesium deficiency has been implicated as a possible contributing factor to some symptoms of premenstrual syndrome (PMS) and several studies have reported a lower intracellular magnesium concentration in women with PMS. Thus, it has been suggested that magnesium supplementation may improve certain symptoms in women with PMS. OBJECTIVE: This open-label study assessed the efficacy and safety of a patented modified-release magnesium 250 mg tablet for improving symptoms in women affected by PMS. METHODS: After a 3-month observational period, women aged 18-45 years with a regular menstrual cycle (from 25-35 days) who were affected by PMS (determined by a score of > or =25 points on a PMS questionnaire) [n = 41] were given the modified-release magnesium tablet over three menstrual cycles, beginning 20 days after the start of their last menstrual period and continuing until the start of their next menstrual period. RESULTS: PMS symptoms improved during magnesium treatment. After 3 months, the mean total PMS score (primary endpoint), as assessed by the investigator using Moos' Modified Menstrual Distress Questionnaire, was significantly lower than before therapy (p < 0.0001). During the same period, the mean PMS scores, as recorded in patients' diaries (secondary efficacy variables), also showed significant improvements (p < 0.0001 for all subscales). The relative decreases in total PMS scores, as assessed by investigator and patient, were 35.1% and 33.5%, respectively. The magnesium tablet was well tolerated, with vertigo the only treatment-related adverse event reported (one patient). CONCLUSIONS: We concluded that modified-release magnesium was effective in reducing premenstrual symptoms in women with PMS in this preliminary study.

Memory effects in nematics with quenched disorder.

We present a combined experimental and Monte Carlo study of a nematic phase in the presence of quenched disorder. The turbidity of a nematic liquid crystal embedded in a porous polymer membrane is measured under different applied field conditions for field-cooled and zero-field-cooled samples. We find that a significant permanent alignment of the nematic can be induced by fields as low as 0.1 V/microm applied during the isotropic to nematic transition. An analogous effect and dependence on sample history is found by studying the order parameter of a sprinkled disorder Lebwohl-Lasher spin model, indicating that dilute quenched randomness is sufficient to produce memory effects in nematics. The large memory induced by field cooling appears to be written in the system during the transition as a result of the field action on freely oriented nematic nuclei. At lower temperature the nuclei consolidate into permanent nematic textures developed from the interaction with quenched disorder.

Nematics with quenched disorder: pinning out the origin of memory.

Memory effects and glassy behavior have been repeatedly observed in disordered nematic liquid crystals but the connection between these effects and the system topology remained unrevealed. We present an analysis of the local and global topology of the nematic ordering in the presence of quenched disorder and we show that nematics with quenched disorder can be mapped into a system of pinned defect lines and that the memory of the system stems from the pinning of these strings.

[Growth rate of abdominal aortic aneurysms. Ultrasounds study and clinical outcome]. / Espansione degli aneurismi dell'aorta addominale. Studio ecografico e outcome clinico.

BACKGROUND: The standard treatment for abdominal aortic aneurysms (AAA) >55 mm is actually represented by surgical repair mainly or by endovascular repair, in selected cases; conversely the debate is still open for those ranging 40-55 mm. These last and smaller aneurysms are usually followed-up by ultrasounds (US), in order to detect too fast expansions and to prevent sudden ruptures. Aim of this study is to present the results of the US follow-up of a series of asymptomatic AAAs and the correlation between expansion rate and associated risk factors. METHODS: All patients evaluated for an AAA between March 1991 and December 2000 were included and, according to the maximum diameters of the infrarenal aorta, were divided into 3 groups: A (26-29 mm), B (30-39 mm) and C (>39 mm). Groups A and B underwent US follow up at 6-month intervals, while group C underwent a complete preoperative evaluation. RESULTS: The mean follow up was 36+/-24 months for the entire series (225 AAA); the mean expansion rate was 1 mm/year for group A, <1.5 mm/year for group B for the first 5 years with a sharp increase (5 mm/year) in the following 2 years and 3 mm/year for group C up to 5 years. Among the associated risk factors, hypertension and smoking have confirmed their main role, independent from the initial diameter (p<0.01). Eight ruptures (3.8%) occurred in patients unsuitable for surgery or who refused it and in 7 cases they were lethal. The range between diagnosis and death (19-61 months) and the maximum size (38-93 mm) were absolutely unpredictable. The remaining 40 deaths were related to vascular diseases (MI and stroke 29.8%) or concurrent neoplasms (29.8%) mainly. The surgical treatment was carried out as elective repair on 45 patients (mortality rate 2.2%) and in emergency in 2 cases, both dead, with a mean interval from diagnosis to surgery of 28+/-17 months. CONCLUSIONS: Our results agree with the literature data concerning the dilatative trend and the risk factors and, according to these, elective repair in patients with AAA ranging 45-55 mm should be considered.

Nematics with quenched disorder: how long will it take to heal?

Nematics with quenched disorder have been repeatedly predicted to form glass phases. Here we present turbidity experiments and computer simulations aimed at studying glass key features such as dynamics and history dependence in randomly perturbed nematics. Electric field-cooling alignment has been employed to prepare samples in suitably oriented starting states. Remarkable remnant order and slow dynamics are found both by experiment and simulations, indicating that random disorder can, by itself, induce a nematic glass state even without perturber restructuring.

Can Joel-Cohen incision and single layer reconstruction reduce cesarean section morbidity?

OBJECTIVE: To compare an innovative cesarean section based on Joel-Cohen incision with the traditional Pfannenstiel technique in terms of operative data and post-operative recovery. METHOD: Out of 158 randomized patients, 83 patients underwent the innovative cesarean section (Joel-Cohen incision, one-layer locked uterine suture, no peritoneization) and 75 the traditional operative approach (Pfannenstiel incision, double layer closure of the uterus, visceral and parietal peritoneization). Operative data and post-operative morbidity were compared; sample size was calculated to detect a 13% difference in the occurrence of post-operative fever with a statistical power of 80%. RESULT: Post-operative fever was not different in the two groups. Total operating time was shorter with the innovative technique: 31.6 +/-1.38 min vs. 44.4+/-1.44 (P=0.0001) and fewer sutures were used: 3.6+/-0.13 vs. 6+/-0.13 (P=0.001). Patients operated by the new technique began moving sooner and intestinal function restarted earlier. CONCLUSION: The proposed technique made for shorter operating times and faster recovery but no decrease in puerperal morbidity.

Controlled fetal blood-letting of the recipient twin as a new method for the treatment of severe twin-twin transfusion syndrome: preliminary results.

OBJECTIVE: To investigate the feasibility of withdrawal of blood from the recipient twin as a new method for the treatment of severe twin-twin transfusion syndrome. METHODS: Seven consecutive monozygotic monochorionic twin pregnancies affected by severe twin-twin transfusion syndrome were treated. Fetal blood was withdrawn from the recipient twin using cordocentesis. The volume of blood to be removed was determined using the formula for intrauterine blood transfusion of anemic fetuses. Fetal outcome was evaluated in relation to changes in the amniotic fluid and in growth curves (comparing the differences between the centiles of the estimated fetal weight before the procedure and the centiles of weight at birth), fetal mortality, gestational age at delivery, neonatal weight and neurological damage. RESULTS: Overall, seven of the 14 (50%) fetuses survived; at least one fetus survived in five (71%) pregnancies, both fetuses survived in two (29%) pregnancies, while in two (29%) pregnancies there were no survivors. No maternal complications were observed. At follow-up, one (14%) baby had minor neurological damage. CONCLUSIONS: Withdrawal of blood from the recipient twin in the treatment of severe twin-twin transfusion syndrome was associated with survival similar to that of the alternative techniques of serial amniodrainage and fetoscopic laser surgery, with some possible advantages such as reduced neurological damage compared with serial amniodrainage. It is also less invasive compared with fetoscopic laser surgery.

Nematics with quenched disorder: what is left when long range order Is disrupted?

It is now generally accepted that even low amounts of quenched disorder disrupt long-range order in anisotropic systems with continuous symmetry. However, very little is known on the key item of the nature of the residual order, if any, and particularly if this has quasi-long-range or truly-short-range character. Here we address this problem both experimentally for the nematic 6CB in dilute aerosils and with computer simulations. We find that the residual order is short ranged and scales with disorder density in agreement with the Imry-Ma argument.

Immunomagnetic isolation of human developing motor neurons.

Human motor neuron (MN) isolation provides a critical tool to study neurophysiological properties and the effects of molecules of clinical relevance on isolated neurons. We developed an immunomagnetic separation technique based on specific MN antigen recognition for nerve growth factor receptor (p75-NGFR). We cultured an average of 250,000 cells from the anterior horns of a single cord (four specimens at postconception Weeks 6.0, 7.2, 8.0, and 8.3). At day 7 in vitro (DIV), choline acetyltransferase (ChAT) and/or p75-NGFR-expressing cells (MNs) represented 72 +/- 2% of the total growing cells. MNs survived for at least 4 weeks in biochemically defined medium. The immunomagnetic separation method has been demonstrated to be effective, reproducible, and quantitative for separation of MNs.

[The evolutionary principles of inguinal hernioplasty through our personal experience]. / Principi evolutivi dell'ernioplastica inguinale attraverso la nostra esperienza personale.

Inguinal hernia is a multi-factorial pathologic condition. A constitutional weakness of transversalis fascia, probably genetically transmitted, represents a fundamental cause. Hernioplasty has evolved year by year from the "Bassini" to the "tension-free" techniques with Marlex or Prolene prosthesis, on the rational base of no tension on constitutionally weak structures. The data reported confirmed the absolute validity of "tension-free" hernioplasty.

[The post-cholecystectomy syndrome. Evaluation of symptomatology using Tc-99m-HIDA sequential hepatic scintigraphy (cholescintigraphy)]. / La sindrome post-colecistectomia. Valutazione della sintomatologia mediante scintigrafia epatica sequenziale (colescintigrafia) HIDA 99mTc.

The authors comment the data from research on 70 patients with post cholecystectomy syndrome, using cholescintigraphy HIDA 99mTc to evaluate the relation ship between symptomatology (see classific.) and duodenogastric reflux entity. Cholescintigraphy seems to be a valid clinical means, especially for a correct indication to endoscopy.

[Seeker, observer and world savant in the 18th century: scientific research in the imagination of Charles Bonnet (1720-1793)]. / Chercheur, observateur et monde savant au XVIIIe siècle: la recherche scientifique dans l'imaginaire de Charles Bonnet (1720-1793).

This article analyses the history of the term "chercheur" from the seventeenth century until the beginning of the twentieth century, focusing, in particular, on the work of the naturalist and philosopher Charles Bonnet (1720-1793) and on research traditions related to the life sciences. Although the term was initially used in a pejorative sense, to describe an English Puritanical sect, it came to assume its modern meaning through a series of transformations.

Prenatal diagnosis of 30 fetuses at risk for fragile X syndrome.

The results of 30 prenatal diagnoses for fragile X syndrome are reported. Amniotic fluid cells were examined in 1 case, fetal blood in 4, and chorionic villi samples in the others. Of the 5 fetuses analyzed by cytogenetic methods, 1 had showed 4% of fraXq27.3 expression sites and the pregnancy was terminated. For 1 diagnosis, linkage analysis was used: the female fetus turned out to be normal. In 24 fetuses, the direct analysis of the mutation by StB12.3 probe was performed: 6 female and 3 male fetuses were found to carry a full mutation and 1 female fetus was found to carry a premutation. In 3 cases, the diagnoses were verified on fetal blood samples. Several tissues of 2 aborted male fetuses were analyzed for the fragile X mutation. The results are reported and discussed.