Direct evidence that twisted flux tube emergence creates solar active regions.

The magnetic nature of the formation of solar active regions lies at the heart of understanding solar activity and, in particular, solar eruptions. A widespread model, used in many theoretical studies, simulations and the interpretation of observations, is that the basic structure of an active region is created by the emergence of a large tube of pre-twisted magnetic field. Despite plausible reasons and the availability of various proxies suggesting the accuracy of this model, there has not yet been a methodology that can clearly and directly identify the emergence of large pre-twisted magnetic flux tubes. Here, we present a clear signature of the emergence of pre-twisted magnetic flux tubes by investigating a robust topological quantity, called magnetic winding, in solar observations. This quantity detects the emerging magnetic topology despite the significant deformation experienced by the emerging magnetic field. Magnetic winding complements existing measures, such as magnetic helicity, by providing distinct information about field line topology, thus allowing for the direct identification of emerging twisted magnetic flux tubes.

Bio-hybrid gold nanoparticles as SERS probe for rapid bacteria cell identification.

This study reports the utilization of engineered molecular networks between bacteriophage (or phage) and gold nanoparticles (AuNPs) prepared ablating a high purity gold target in water by nanosecond laser source. Gold colloids are assembled with P9b phage clone, displaying the specific peptide (QRKLAAKLT), able to bind P. aeruginosa. The single components and assembled systems were characterized by spectroscopic and electronic techniques, such as the conventional optical absorption and micro-Raman spectroscopies as well as the Dynamic Light Scattering (DLS) and Scanning Transmission Electron Microscopy (STEM) techniques. The performance of the AuNPs-phage assembly as substrate for Surface-Enhanced Raman Spectroscopy (SERS) was tested against the detection of the characteristics Raman vibrational features of the Pseudomonas aeruginosa bacteria.

Protein adsorption and fibroblast adhesion on irradiated polysiloxane surfaces.

A very peculiar case of differential cell response towards polysiloxane surfaces of very similar composition is investigated. Poly(hydroxymethylsiloxane) (PHMS) surfaces treated either by O(2)-plasma or 6 keV Ar(+)-beams have been used to test the adhesion, proliferation and spreading of human fibroblasts. The surface chemical structure and nanomorphology were investigated by means of X-ray photoelectron spectroscopy (XPS), surface free energy measurements and atomic force microscopy (AFM). In spite of the close compositional and morphological similarity of the modified surfaces, the viability of the adhered cells, evaluated by means of optical microscopy and epifluorescence microscopy, was found to be very different in the two cases. The study of the features of the adsorbed protein adlayer on the two types of surfaces was performed by XPS and AFM and indicated that the overall cell behavior is connected to a quite different protein aggregation process, occurring respectively on the plasma- and Ar(+)-modified polysiloxane surfaces. It is suggested that the specific biological response of the modified surfaces is determined by the chemical structure at the nanometric level.

Morphologic variations in bacteria under stress conditions: near-field optical studies.

The morphologic and structural variations suffered by cells of a population of Pseudomonas aeruginosa ATCC 27853 under stress conditions were investigated by using scanning near-field optical microscopy. The analysis of the images, supported by microbiological data, showed that the bacteria evolved from the initial distribution of rod-shaped cells of standard size to a population with structural and morphologic modifications. The detection of variations in the optical reflectivity over a subwavelength scale (< or = 100 nm), combined with the concurrently acquired topographical signal, allowed the visualisation of rod-shaped bacteria going towards a lytic process and entire "U"-shaped cells. In the latter cells, which derived from a morphology refolding of rod bacteria, cellular matter seemed to rearrange itself to attain a coccoid stress resistant form, responsible for the residual viability of the population.

Biosynthesis and structural characterization of medium-chain-length poly(3-hydroxyalkanoates) produced by Pseudomonas aeruginosa from fatty acids.

In this study, we investigated the ability of Pseudomonas aeruginosa ATCC 27853 to grow and synthesize poly(3-hydroxyalkanoates) (PHAs) from saturated fatty acids with an even number of carbon atoms, from eight to 22, and from oleic acid. In a non-limiting medium, all carbon sources but docosanoic acid supported cell growth and PHA production, with eicosanoic acid giving the highest yield. In magnesium-limiting conditions, higher yields were obtained from sources with up to 16 carbon atoms. Composition was estimated by gas chromatography of methanolyzed samples and (13)C nuclear magnetic resonance. The 3-hydroxyalkanoate units extended from hexanoate to tetradecanoate or tetradecenoate, with octanoate and decanoate as the predominant components. Weight average molecular weights ranged from 78,000 to 316,000. Fast atom bombardment mass spectrometry of partially pyrolyzed samples, coupled to statistical analysis, showed that these PHAs are random copolymers.

Herpes simplex virus 2 causes apoptotic infection in monocytoid cells.

Increasing evidence indicates that apoptosis can be associated with several viral infections. Here we demonstrate, that infection of monocytoid cells by Herpes simplex virus 2 (HSV-2) resulted, in time- and dose-dependent induction of apoptosis as an exclusive cytopathic effect. The phenomenon was confirmed using four different techniques. Conversely, apoptosis was not observed in the Vero cell line. Virus yield in monocytoid cells was delayed and reduced, although well detectable, in comparison with that observed in Vero cells. Nevertheless, released virions exhibited full infecting capability. Apoptosis induced by HSV-2 was not inhibited by cycloheximide and only partially by an UV-treatment which completely abrogated infectivity. Virus-induced apoptosis was partly inhibited by indomethacin and was associated with a down-regulation of Bcl-2. A similar, but less pronounced, apoptosis-inducing effect in monocytoid cells was also observed with HSV-1 infection. Depending on the target cells, therefore, HSV could complete a cycle of infection which is characterized by apoptosis of infected cells.

Detection of immunoglobulin G to a Sindbis-related virus by a membrane antigen enzyme immunoassay.

We determined the seroprevalence of a Sindbis-related virus isolated for the first time in 1975 from ticks in south-east Sicily and typed by Gresikova et al. in 1978. An indirect enzyme immunoassay based on viral membrane antigen for coating microtiter strips was used for the detection of immunoglobulin G to the Sindbis-related virus. The method appeared more sensitive than a similar enzyme immunoassay based on crude lysate antigen. Comparison of the results obtained from sera tested both by membrane antigen enzyme immunoassay and microneutralization test showed 92% agreement, while the agreement between microneutralization test and crude antigen enzyme immunoassay was 76%. An overall elevated seroprevalence (63.66%) was found in a population group living in and around the area of first isolation and seroprevalence in different age groups was also studied.

Anti-HCMV serologic response in patients with acute viral hepatitis.

The authors point out a high serological incidence of HCMV infection in the course of HCV hepatitis compared to a low incidence detected in HBV and HAV hepatitis. Three immunoglobulin classes (IgG, IgM, and IgA) specific to HCMV were investigated. Antibody titers of each immunoglobulin class are reported for all the cases of HCMV infection.

Scrotoscopy: a promising future? Our preliminary experience.

Scrotoscopy is a new endourologic technique for the exploration of the scrotum. After distention of the tunica vaginalis space with saline, a standard arthroscope was employed in 20 cadavers and subsequently in 5 patients before full surgical exploration for hydrocele (1 case), testicular biopsy (3 cases), or orchidectomy (1 case). There was a clear view of the testis and epididymis. The procedure was easy, and there were no major complications. Scrotoscopy could potentially be performed on an outpatient basis. Its indications in infertility appear to be particularly promising.

Serum IgA antibodies in HSV asymptomatic genital infections.

Cervico-vaginal swabs and serum samples from 81 women without herpes-associated clinical symptoms were examined for virus isolation and for the presence of IgA antibodies to herpes simplex virus (HSV) using the indirect fluorescent antibody technique. Nineteen of the 81 women were followed up for 2 years. Blood samples and swabs from cutaneous lesions were obtained from another group of 20 women (medical staff) with herpes labialis. By analysing the specific anti-HSV IgA antibodies, a higher geometric mean titre (GMT) was found in women with positive HSV-2 isolation (GMT = 380.03), as opposed to the GMT observed in women with negative HSV-2 (GMT = 63.43) or positive HSV-1 isolation (GMT = 55.15). Results from the longitudinal study also demonstrated that positive virus isolation always correlated with a marked rise in serum IgA antibody to HSV.

The role of anti-herpes specific serum IgA levels as a marker in cervical oncogenesis.

In the last few years, a great effort has been made with the aim of discovering cervical cancer etiology factor(s). At present, both HSV and HPV have been demonstrated strictly associated with cervical premalignant and malignant lesions. Nevertheless problems do exist in achieving the definitive evidence of a causative role exerted by herpes virus and/or by papilloma virus. Starting from 1984, our group studied the humoral immune response against herpes virus type two, in patients affected with CIN and invasive cervical cancer, as well as with atypical metaplasia and papilloma virus cytopathic effect at pap test, giving in 1985, the first evidence that serum levels of specific anti-herpes IgA strictly correlates both with infections and viral shedding, even when asymptomatic, as with various stages in cervical oncogenesis. This study updates our previous reports showing that IgA serum levels may be a useful marker in herpes related human diseases. Finally, data show the preliminary evidence that IgA, when levels are determined in the male partners of patients, is also useful in the screening and detection of "high risk males". These data, if further confirmed, will be of great advantage in the clinical monitoring of cervical cancer treatments, as well as in management and follow-up of preinvasive epithelial lesions of the cervix.

[Comparative studies of the results of caloric vestibular tests and classical torsion swing tests]. / Etude comparative des résultats des épreuves vestibulaires caloriques et de l'épreuve pendulaire classique.

Vestibular Paresis (PL) and Directional Preponderance (PD) are the measurements found on caloric testing described by Fitzgerald and Hallpike (1942); frequency nystagmogram is the typical result of the torsion swing test of the French school. The differences between the two methods stimulated us to make a comparison of the results. Seventy-eight patients affected by unilateral peripheral vestibulopathy in various degree of compensation were submitted to both tests. Frequency nystagmogram was transformed, for calculation purposes, into normalized percentual difference (SSP). SSP and PD were found highly significantly correlated and were considered as equivalent from the statistical point of view. SSP and PL were completely independent at slow velocity stimulation. Using high velocities of stimulation a correlation was demonstrated between SSP and PL; unfortunately to the elevation of SSP corresponds a so minimal increasing of PL that the correlation is scarcely useful from the clinical point of view.

[The occurrence of nystagmus in sustained sinusoidal stimulation]. / La fréquence nystagmique dans la stimulation sinusoïdale entretenue.

Twenty normal subjects have been submitted to a set of vestibular sinusoidal stimulations, the maximal acceleration per hemiperiod being constant. However the nystagmic response (number of beats per hemiperiod) was not constant, but increased during every single trial. The clinical consequences of this observation are discussed. In particular authors suggest that the classical damped sinusoidal stimulation test should be considered a semi-quantitative test.

H-1 and X14 parvovirus antibodies in women with abortions or still-births.

Antibodies against H-1 and X14 parvoviruses were found 13.71 and 9.14%, respectively, of 350 sera from women affected by repeated abortions or still-births. On the contrary, only 2.66 and 1.66% of 300 control sera were positive to the two viruses. The difference in the incidence of antibodies appears highly significant (p greater than 0.001). Therefore a possible role of the parvoviruses in inducing abortions or still-births in humans is suggested.