Importance of attentional mechanisms in audiovisual links

The effect of auditory cues at different levels of visual processing was examined by using a visual "conjunction of features" discrimination task (experiment 1) and a "feature" discrimination task (experiment 2). In both experiments the visual target, appearing either on the left or the right of Ss' midline, was preceded by a brief tone either spatially proximal or distal to the target. In the "conjunction" task, subjects had to discriminate the orientation of a T flanked with T distractors of different orientations. In this task, assumed to require focused attention, discrimination accuracy was increased when the sound cue occurred at the subsequent visual target location and was decreased when it occurred at its alternative location. In the "feature" experiment, subjects had to discriminate the orientation of a line segment (+/-45 degrees) presented among line segment distractors. Accuracy was not affected, either when the sound was proximal or when it was distal to the location of the visual target. Results suggest that the early processing of sensory information is modality specific and that interference of auditory stimulation with visual stimuli is more pronounced as the processing of visual stimuli requires focused attention.

Low serum interleukin-10 levels in multiple sclerosis: further evidence for decreased systemic immunosuppression?

Serum interleukin 10 (IL10) levels were assessed in patients with multiple sclerosis who were either in a stable or active clinical condition. The levels were compared with values in healthy controls. Lower IL10 levels than in controls were seen in multiple sclerosis patients, regardless of clinical disease activity. Low IL10 levels were also seen in patients with systemic lupus erythematosus. No clear-cut relationships emerged between IL10 levels and those of tumour necrosis factor alpha and transforming growth factor beta, or between IL10 and lymphocyte subsets in peripheral blood.

A motile but non-swarming mutant of Proteus mirabilis lacks FlgN, a facilitator of flagella filament assembly

A TnphoA mutant of Proteus mirabilis was isolated, which had lost the ability to swarm, yet was still motile. The transposon had inserted into flgN, a flagella gene encoding a 147-amino-acid protein of undefined function. Proteus flgN is arranged in an operon with the class III anti-sigma28 gene, flgM, flanked by the class II genes, flgA, flgBCD and flhBA, and a novel putative virulence-related gene. The flgN mutation caused a substantial reduction in cell surface-associated flagellin, particularly during differentiation to the normally hyperflagellated swarm cell. This was not due to an effect on flagella gene expression or a typical defect in the flagella export apparatus as there was no class III gene downregulation by FlgM feedback, or intracellular flagellin accumulation. Loss of FlgN nevertheless caused a severe reduction in the incorporation of pulse-labelled flagellin into the membrane/flagellum fraction of differentiating cells. Substantial amounts of both non-oligomeric flagellin and flagellin degradation products appeared in the extracellular medium, although the few mature filaments made by the mutant were no more sensitive to proteolysis than those of the wild type. FlgN appeared soluble and active in the cytosol. The data suggest that the function of FlgN is to facilitate the initiation of flagella filament assembly, a role that may be especially critical in attaining the much higher concentration of surface flagellin required for swarming. Proteus FlgN has leucine zipper-like motifs arranged on potential amphipathic helices, a feature conserved in cytosolic chaperones for the exported substrates of flagella-related type III virulence systems. While gel filtration of FlgN from the soluble cell fraction did not establish an interaction with flagellin, it indicated that FlgN may associate with an unknown component and/or form an oligomer.

Immunocompetence of human microvascular brain endothelial cells: cytokine regulation of IL-1beta, MCP-1, IL-10, sICAM-1 and sVCAM-1

Endothelia from the brains of four patients undergoing neurosurgery, including one multiple sclerosis (MS) patient, were studied in vitro to determine cytokine and chemokine production; the release of soluble adhesion molecules was also investigated. The same procedure was repeated on human umbilical vein endothelial cells (HUVECs) in order to detect possible district-specific differences. After isolation, the endothelium was cultured and stimulated with gamma-interferon (IFN), tumour necrosis factor alpha (TNF-alpha) and LPS. The results showed that brain endothelium, in our experimental conditions, does not produce interleukin (IL)-10 and produces lower amounts of IL-1beta and soluble intercellular adhesion molecule-(sICAM-1) than HUVECs do; no differences were detected in soluble vascular cell adhesion molecule-(sVCAM-1) production. MCP-1 mRNA was detected both without and after stimulation with TNF-alpha and gamma-IFN in HUVECs and MS human brain endothelial cells (HBECs), while in non-MS-HBECs it was found only after gamma-IFN stimulation.

Effects of beta-IFN-1b treatment in MS patients on adhesion between PBMNCs, HUVECs and MS-HBECs: an in vivo and in vitro study

The in vivo effects on the expression of adhesion molecules and on the adhesion between mononuclear cells and multiple sclerosis human brain endothelial cells (MS-HBECs) were investigated at the beginning of beta-IFN-1b treatment of MS patients. MS-HBECs were isolated from a surgical specimen obtained from an MS patient undergoing brain surgery for vascular aneurysm. 48 h after the first single administration of beta-IFN-1b, PBMNCs of 10 MS patients were analyzed for HLA-DR, CD11a, CD18 and VLA-4 expression and the adhesion between PBMNCs and both stimulated and unstimulated MS-HBECs evaluated. sICAM-1 and sVCAM-1 dosage in the serum of the patients was checked as well. The experiments were repeated using HUVECs in order to detect possible endothelial organ-specific differences. The experiments were also performed after six months of beta-INF-1b treatment on HUVECs. No significant effects on mononuclear cells/endothelium adhesion were detected at 48 h, but adhesion of PBMNCs to HUVECs decreased at six months. An increase in HLA-DR and VLA-4 and a decrease of CD18 was detected in monocytes. The serum level of sVCAM-1 increased at T2 and was still higher than at T0 at six months. The effect of the beta-IFN-1b treatment on both MS-HBECs and HUVECs, was selectively studied in vitro by testing the expression of cytokine-induced adhesion molecules HLA-DR, ICAM-1 and VCAM-1. The in vitro experiments confirmed that beta-IFN-1b is able to antagonize gamma-IFN-induced HLA-DR expression on MS human brain endothelial cells without relevant effects on VCAM-1 and ICAM-1.

The extrinsic/intrinsic classification of two-dimensional motion signals with barber-pole stimuli

The perceived direction of different barber-pole stimuli was assessed by adjusting an arrow on the screen. The terminator ratio (TR: number of terminators moving along the long side divided by the number of terminators moving along the small side) was either one or three. In this latter case, the aperture orientation was either vertical or horizontal. The grating was either in the same plane as the aperture (intrinsic condition) or behind the aperture--the frame containing the aperture had a crossed disparity relative to the grating--(extrinsic condition). A nested design with 120 observers was used for the whole study. Five grating orientations were intermingled within any session. With a terminator ratio of three, the results depend strongly on the aperture's orientation. When the rectangular aperture is horizontal, the perceived direction of an intrinsic grating is horizontal (the typical barber-pole illusion), whereas it is only slightly biased towards orthogonal one-dimensional (1D) motion signals (Vp) in the extrinsic condition. When the aperture is vertical, the perceived direction in the intrinsic condition is largely biased toward Vp, and on average it is close to Vp in the extrinsic condition. In this latter case, however, analysing the distributions of responses shows that many responses do not lie around Vp but are clustered near vertical or horizontal. This motion capture depends on the grating's orientation. With a terminator ratio of one, motion capture is present in both the extrinsic and intrinsic conditions. Moreover, a global bias toward horizontal is observed: this horizontal bias is much larger in the extrinsic condition. Altogether, these results suggest that binocular disparity alone is a weak determinant of the extrinsic/intrinsic classification of two-dimensional (2D) motion signals compared to the occlusion cues provided by unpaired regions in binocular images. Second, truly extrinsic 2D motion signals are not suppressed but rather actively compete against each other to capture the 1D motion signals. This results in a perceptual multistability which is much stronger with extrinsic signals. Finally, given the inherent multistability of barber-pole stimuli, high-level factors can alter the strength of this competition and prime any of the 2D motion signals.

Association of hepatitis B virus infection with other sexually transmitted infections in homosexual men. Omega Study Group

OBJECTIVES

This study determined the prevalence and factors associated with hepatitis B virus (HBV) infection among men who have sex with men.

METHODS

At the baseline visit of an HIV study among men who have sex with men, we asked about HBV vaccination status and tested for HBV markers.

RESULTS

Of 625 subjects, 48% had received at least 1 dose of HBV vaccine. Of 328 unvaccinated men, 41% had 1 or more HBV markers. HBV prevalence increased markedly with age and was associated with many sexual and drug-related behaviors. In a multivariate model, 7 variables were independently associated with HBV infection: ulcerative sexually transmitted diseases (odds ratio [OR] = 10.1; 95% confidence interval [CI] = 2.6, 54); injection drug use (OR = 5.2; 95% CI = 1.2, 26); gonorrhea or chlamydia (OR = 4.0; 95% CI = 1.9, 8.9); sexual partner with HIV/AIDS (OR = 3.6; 95% CI = 1.8, 7.1); 50 or more casual partners (OR = 3.4; 95% CI = 1.6, 7.1); received money for sex (OR = 3.0; 95% CI = 1.2, 7.8); and 20 or more regular partners (OR = 2.5; 95% CI = 1.1, 6.1).

CONCLUSIONS

In Montreal, men who have sex with men are at risk for HBV infection, but a substantial proportion remain unvaccinated; new strategies are required to improve coverage. Men who have sex with men and who have a sexually transmitted infection, especially a genito-ulcerative infection, appear to be at particularly high risk for HBV infection.

Factors associated with hepatitis B vaccination among men having sexual relations with men in Montreal, Quebec, Canada. Omega Study Group

OBJECTIVE

To determine factors associated with hepatitis B virus (HBV) vaccination status among HIV-uninfected men who have affective and sexual relations with men (MASM) in Montreal, Quebec, Canada.

METHODS

The Omega Cohort is a study of the incidence and psychosocial determinants of HIV infection among MASM in Montreal. Participants complete a questionnaire and are HIV-tested every 6 months. At baseline, we also performed testing for HBV markers and collected data on HBV vaccination history.

RESULTS

Forty-six percent of 653 participants had received at least one dose of HBV vaccination, whereas 28% were completely vaccinated. Lack of vaccination was associated with injection drug use, having > or =20 regular lifetime partners, living outside Montreal, not having sex in bathhouses, and not having consulted a physician aware of the participant's sexual orientation. Among vaccinated MASM, incomplete vaccination was associated with having <20 lifetime casual partners, trading sex for drugs, having given goods for sex, having had unprotected anal sex with regular partners, and having no history of a previous sexually transmitted disease.

CONCLUSION

A significant proportion of Montreal's MASM, some of whom are at risk of contracting HBV through sexual and parenteral transmission, have not been vaccinated for HBV. Men who have affective and sexual relations with men should be educated about the risk of HBV transmission and the seriousness of the disease.

High-dose methylprednisolone reduces cytokine-induced adhesion molecules on human brain endothelium

OBJECTIVE

We investigated the in vitro effects of low- and high-dose methylprednisolone (MP) on the cytokine-induced expression of HLA-DR, ICAM-1 and VCAM-1 on human brain microvessel endothelial cells (HBMECs).

METHODS

Brain endothelium was obtained from microvessels included in the apparently normal white matter of surgical specimens of nine patients. Cells were stained with monoclonal antibodies anti-HLA-DR, anti-ICAM-1 and anti-VCAM-1 and analysed by flow cytometry as fluorescence histograms. The mean fluorescence intensity (MFI) of HBMECs treated with different stimuli was calculated.

RESULTS

gamma-IFN-induced HLA-DR was down-regulated in a dose-dependent manner by MP. High-dose MP reduced the TNF-alpha-induced ICAM-1 and VCAM-1 expression.

CONCLUSIONS

The down-regulation of adhesion molecules on cerebral endothelial cells could decrease mononuclear cell transmigration through the blood brain barrier and consequently the perivascular infiltrates. The results add support to the rationale for high-dose MP treatment in multiple sclerosis relapses.

Lantibiotic biosynthesis: interactions between prelacticin 481 and its putative modification enzyme, LctM

Class AII and AIII lantibiotics and mersacidin are antibacterial peptides containing unusual residues obtained by posttranslational modifications of prepeptides, presumably catalyzed by LanM. LctM, the LanM for lacticin 481, is essential for the production of this class AII lantibiotic. Using the yeast two-hybrid system, we showed direct contact between the prelacticin 481 and LctM, supporting the proposed LctM function. Sixteen domains are conserved between the 10 known LanM proteins, whereas three additional domains were found only in class AII LanM proteins and in MrsM, the LanM for mersacidin. All the truncated LctM proteins that we tested presented impaired LctA-binding activity.

Plasmid-encoded determinants for bacteriocin production and immunity in a Lactococcus lactis strain and purification of the inhibitory peptide

Lactococcin, a bacteriocin produced by Lactococcus lactis subsp. lactis ADRIA 85LO30, was purified as a 2.3-2.4 kDa peptide. Six non-bacteriocin-producing (Bac-) and non-immune (Imm-) strains were isolated after curing experiments. These strains had in common the loss or modification of two plasmids: pOS4 (32 kb) and pOS5 (70 kb). By comparing pOS5 and several modified plasmids, a DNA region from pOS5 of about 10 kb, which was necessary for wild-type bacteriocin production and immunity, was identified.

IS1675, a novel lactococcal insertion element, forms a transposon-like structure including the lacticin 481 lantibiotic operon

Two copies of IS1675, a novel lactococcal insertion element from the IS4 family, are present on a 70-kb plasmid, where they frame the lantibiotic lacticin 481 operon. The whole structure could be a composite transposon designated Tn5721. This study shows that the lacticin 481 operon does not include any regulatory gene and provides a new example of a transposon-associated bacteriocin determinant. We identified five other IS1675 copies not associated with the lacticin 481 operon. The conservation of IS1675 flanking sequences suggested a 24-bp target site.

Correlates of risky behaviors among young and older men having sexual relations with men in Montréal, Québec, Canada. Omega Study Group

OBJECTIVE

To assess characteristics associated with 1) age and 2) recent unprotected anal sex with casual partners among men having sexual relations with men (MSM) participating in the Omega Cohort, Montréal, Québec, Canada.

METHODS

The Omega Cohort is a study of the incidence and psychosocial determinants of HIV infection among MSM living in Montréal. MSM complete a questionnaire and are tested for HIV every 6 months.

RESULTS

Thirteen percent of young MSM (< 30 years of age, n = 355) and 12% of older MSM (> or = 30 years of age, n = 455) reported recent unprotected anal sex with casual partners. The predictors of this latter behavior were: not living with a male sexual partner, unprotected anal sex with regular partner, > 5 casual partners, alcohol/drug use before anal sex, and having difficulties with procedures needed for safe sex. Among young MSM, additional predictors were: to have been living in Montreal for less than 1 year and to have exchanged money for sex. Among older MSM, additional predictors were: female sexual partners, unprotected anal sex with an HIV-infected partner, and feeling invulnerable to AIDS.

CONCLUSION

Young Omega participants do not have more risky behaviors than older participants. Some predictors of recent risk behaviors with casual partners were different between the two groups. Prevention programs should be adapted consequently.

Spatial auditory compensation in early-blind humans: Involvement of eye movements and/or attention orienting?

Several studies have reported that the early-blind displays higher auditory spatial abilities than the sighted. Although many studies have attempted to delineate the cortical structures that undergo functional reorganization in blind people, few have tried to determine which auditory or non-auditory processes mediate these increased auditory spatial abilities. The aim of this paper is to investigate the role of eye movements and orientation of attention in auditory localization in blind humans. Although we found, in a first experiment, that the influence of eye movements on auditory spatial localization is preserved in spite of congenital visual deprivation, the saccade influence on spatial hearing is not more pronounced in the blind than in the sighted. In a second experiment, early-blind and sighted subjects undertook a task involving discrimination of sound elevation in which auditory targets followed uninformative auditory cues on either side with an intermediate elevation. When sounds were emitted from the frontal hemifield, both groups showed similar auditory localization performance. Although the auditory cue did not affect discrimination accuracy in both groups, early-blind subjects exhibited shorter reaction times than sighted subjects when sound sources were placed at far-lateral locations. Attentional cues, however, had similar effects on both groups of subjects, suggesting that improved auditory spatial abilities are not mediated by attention orienting mechanisms.

Anterior and non-anterior ruptured aneurysms: Memory and frontal lobe function performance following coiling

Our aim was to compare memory and frontal function performance between two groups of patients treated with Guglielmi detachable coil (GDC) following intracranial ruptured aneurysm. The subgroups drawn following the localization of the aneurysm consisted of 19 patients presenting with anterior communicating artery aneurysms and 16 patients exhibiting middle cerebral artery and posterior communicating artery aneurysms. The 35 patients and 35 normal controls were administered extensive neuropsychological assessment. Additionally, a scale of qualitative changes of mood was presented to the patients and patients' relatives. The patients showed a better general performance on memory compared with the executive function performance, which was similarly impaired in both groups. We suggest that executive functions are more vulnerable to differently located lesions than memory functions.

Modulation of ICAM-1, VCAM-1 and HLA-DR by cytokines and steroids on HUVECs and human brain endothelial cells

The in vitro effects of dexamethasone (Dx) and low and high-dose 6-methylprednisolone (MP) on the expression of adhesion molecules ICAM-1,VCAM-1 and class II antigen HLA-DR on human brain endothelial cells (HBECs) was studied. HBECs were obtained from the surgical specimen of a multiple sclerosis patient undergoing brain surgery for vascular aneurysm. HBECs obtained from apparently normal brain capillaries of surgical specimens of two patients undergoing brain surgery for a meningioma and a low-grade glioma, respectively, were used as controls. The effect of steroids was studied both in the basal condition and after stimulation with proinflammatory cytokines (gamma-IFN and TNF-alpha). In order to detect possible endothelium local tissue specific differences, the experiment was repeated using human umbilical vein endothelial cells (HUVECs). Only high-dose MP was able to down-regulate TNF-alpha-induced VCAM-1 expression on endothelial cells.

Improved auditory spatial sensitivity in near-sighted subjects

There is a great deal of anecdotal and empirical evidence in favor of compensatory plasticity of the sensorial modalities when one of them undergoes a total deficit. Yet, while most research has focused on the development of spatial hearing in totally blind individuals, there are few works dealing with auditory compensation in the case of a partial visual deprivation. In the present study, three experiments show that subjects undergoing a visual deficit like myopia are more accurate at localizing sounds than normal-sighted subjects.

Haemodynamic effects of intravenous cibenzoline in patients with coronary heart disease

The effect of a single dose of cibenzoline ( (diphenyl 2,2 cyclopropyl)--2 imidazoline, Cipralan ), a new compound with antiarrhythmic properties was studied in 14 patients undergoing routine heart catheterization for suspected coronary artery disease. The effect of the drug on dP/dt, Vmax TP, Vce, negative dP/dt, heart rate (HR), left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), cardiac index (CI) and systemic vascular resistance (SVR) was measured before and after drug administration. A significant decrease in left ventricular isometric contraction parameters was manifested immediately after injection, with its maximal effect 2 to 5 min after injection. An increase in HR, a decrease in LVSP, a decrease in CI and an increase in SVR were observed; LVEDP was not significantly altered, nor was negative dP/dt. The effect of the drug on Vmax TP and LVEDP was also examined during two atrial pacing stress tests ( APST ) done before and 10 to 20 min after drug administration. Although the negative inotropic action of the drug was apparent during the second APST , the effect was less pronounced at higher paced heart rates. No difference in the two tests was found between the maximal paced heart rate, nor was there a difference in the angina threshold. Finally the plasma level of the drug and the changes in certain parameters were compared. A positive correlation was found between the plasma level and dP/dt, Vmax TP and cardiac index.

Electrophysiologic effects of cibenzoline in humans related to dose and plasma concentration

The electrophysiologic effects of a new antiarrhythmic agent, cibenzoline, were investigated in 25 patients with an average age of 62 years. The compound was administered intravenously, as a bolus given over 2 minutes, then as a slow infusion over 40 minutes. Each subject was randomly allocated to receive one of the following four doses: 1.55 mg/kg (six patients), 1.8 mg/kg (six patients), 2.2 mg/kg (six patients), or 2.6 mg/kg (seven patients). Plasma cibenzoline concentrations at these doses were 378 +/- 80,525 +/- 194, 618 +/- 72, and 731 +/- 196 ng/ml, respectively. Administration of 1.55 mg/kg cibenzoline significantly shortened the sinus cycle (60 msec on average; p less than 0.025) and increased intraatrial (+8 msec; p less than 0.05) and His-Purkinje conduction times (HV interval + 13 msec; p less than 0.001). At 1.80 mg/kg, prolongation occurred in the HV interval (+9 msec; p less than 0.02), the duration of the QRS complex (+20 msec; p greater than 0.05), and the QT interval (+18 msec; p less than 0.025). At the higher doses these changes became more marked (maximum increase: HV = +16 msec, p less than 0.001; QRS + 25 msec; p less than 0.001; QT + 26 msec, p less than 0.05), and additional effects on atrioventricular nodal conduction time (AH interval + 17 msec; p less than 0.05) and atrial (+20 msec; p less than 0.05) and ventricular (+10 msec; p greater than 0.05) effective refractory periods were observed. Prolongation of the QRS duration was the effect that correlated best with plasma cibenzoline levels (r = 0.47; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Auditory compensation in myopic humans: involvement of binaural, monaural, or echo cues?

The purpose of this paper is to investigate the involvement of various auditory localization mechanisms in the improvement of auditory spatial sensitivity in the case of partial visual deprivation. We compared sensitivity to binaural, monaural, and echo cues between normal-sighted and myopic subjects. In an auditory task, which depended solely upon binaural processing, myopic and normal-sighted subjects showed an almost equal localization performance. We also found that myopic subjects were no more disturbed than normal-sighted subjects when spectral shape cues were removed. On the other hand, near-sighted subjects exhibited better echolocation skills and a higher sensitivity to echo cues than normal-sighted subjects. We can therefore conclude that an improved auditory spatial sensitivity in myopic subjects may result from the increased use of echo information.

Immunological fluctuations during intrathecal immunotherapy in three patients affected by CNS tumours disseminating via CSF

The immunological therapy of cancer has been proposed in a number of neoplasms (Borden, Sondel, 1989; Foon, 1989; Rosenberg, 1992) and has recently been adopted in the treatment of Central Nervous System (CNS) tumors in combination with conventional surgical and radiotherapeutical approach. In this context, loco-regional administration of immunomodulating agents (for instance in post-surgical cavity) allows to achieve much higher in situ concentrations than by systemic route. Since these treatments have potential adverse effects, careful assessment of clinical and immunological parameters in phase I trials is needed. CNS tumors disseminating via Cerebrospinal Fluid (CSF) pathways offer a stimulating opportunity for intrathecal immunotherapy. In this context, alpha-IFN and IL2 (alone or in combination with LAK cells) have been employed either loco-regionally or intrathecally (Merchant, Mc Vicar, Merchant & Young, 1992; Schiller, Hank, Storer, Borchert, Moore, Albertini, Bechhofer, Wesley, Brown, Bastin & Sondel, 1993). The rationale for the use of both these substances includes the known anti-tumor action of alpha-IFN (Mahaley, Urso, Whaley, Blue, Williams, Guaspari & Selker, 1985; Nagai, 1988) and the ability of r-IL2 to generate activated cells effective in lysing tumor cell targets (Hayes, Moore, Pierz, Chen, Da Rosso, Nirenberg & Allen, 1993). We treated 3 patients (2 affected by disseminating cerebellar medulloblastoma, 1 by disseminating thalamic glioblastoma) by intrathecal r-IL2 via recervoir. In the first 2 patients, this treatment was preceded by alpha-IFN (also intrathecally). Monitoring of immunological effects of the treatment schedule involved kinetics of CSF and serum TNF-alpha, IL2s and IL2R during the first day of r-IL2 treatment, as well as on day +2 and +4 of both r-IL2 cycles, and assessment of CSF cells, protein and CSF and PB NK cell activity and CD3-CD56+ cells during the course of all treatment cycles. We also assessed clinical and neuroradiological effects of immunotherapy.