Direct Observation of Optical Field Phase Carving in the Vicinity of Plasmonic Metasurfaces.

Plasmonic surfaces are mainly used for their optical intensity concentration properties that allow for enhancement of physical interaction like in nonlinear optics, optical sensors, or tweezers. Phase response in plasmonic resonances can also play a major role, especially in a periodic assembly of plasmonic resonators like metasurfaces. Here we show that localized surface plasmons collectively excited by a guided mode in a metallic nanostructure periodic chain present nonmonotonous phase variation along the 1D metasurface, resulting from both selective Bloch mode coupling and dipolar coupling. As shown by near-field measurements, the phase profile of the highly concentrated optical field is carved out in the vicinity of the metallic metasurface, paving the way to unusual local optical functions.

Observation of near-field dipolar interactions involved in a metal nanoparticle chain waveguide.

We present near-field measurements of transverse plasmonic wave propagation in a chain of gold elliptical nanocylinders fed by a silicon refractive waveguide at optical telecommunication wavelengths. Eigenmode amplitude and phase imaging by apertureless scanning near-field optical microscopy allows us to measure the local out-of-plane electric field components and to reveal the exact nature of the excited localized surface plasmon resonances. Furthermore, the coupling mechanism between subsequent metal nanoparticles along the chain is experimentally analyzed by spatial Fourier transformation on the complex near-field cartography, giving a direct experimental proof of plasmonic Bloch mode propagation along array of localized surface plasmons. Our work demonstrates the possibility to characterize multielement plasmonic nanostructures coupled to a photonic waveguide with a spatial resolution of less than 30 nm. This experimental work constitutes a prerequisite for the development of integrated nanophotonic devices.

Sulfide Deposits from the East Pacific Rise Near 21{degrees}N.

Massive sulfide deposits were discovered from the diving saucer Cyana on the accreting plate boundary region of the East Pacific Rise near 21 degrees N. The deposits form conical and tubular structures lying on a basaltic basement. Mineralogical and geochemical analyses showed two main types of intimately associated products: a polymetallic sulfide-rich material composed of pyrite and marcasite in association, zinc-rich phases, and copper-rich compounds, and an iron-rich oxide and hydroxide material (also called gossan) composed largely of goethite and limonite. Silicate phases such as opaline, silica, iron-silicon clay, and trace amounts of mica and zeolite are encountered in both types of material. Possible mechanisms for the formation of the sulfide deposits on the East Pacific Rise are discussed.

East Pacific Rise Near 13{degrees}N: Geology of New Hydrothermal Fields.

Abundant massive sulfide deposits are present at the crest of the East Pacific Rise near 13 degrees North, where the opening rate is about 12 centimeters per year. Large manganese and helium-3 anomalies in seawater samples, evidence of intense present-day activity of hydrothermal springs, indicate that sulfides are still being produced along this segment of the rise. Massive sulfides also occur on adjacent off-axis seamounts.

A novel flow cytometric assay for quantitation and multiparametric characterization of cell-mediated cytotoxicity.

Cell-mediated cytotoxicity is a crucial mechanism involved in several fundamental immunological processes such as protection against intracellular pathogens or termination of an immune response. This phenomenon is classically evaluated by the 51Cr release assay, which requires a radioactive isotope and does not permit the characterization of cells involved in the cytotoxic reaction. We describe a new flow cytometry method, developed in the context of CD95-mediated cell death, which allows the precise quantitation of cell-mediated cytotoxicity and the detection of intracellular events involved in the cytotoxic process. This assay uses a combination of two dyes, i.e. 5- (and 6-) carboxyfluorescein diacetate succinimydyl ester (CFSE) to label effector cells and 7-amino actinomycin D (7-AAD) to stain apoptotic target cells. We show that this assay is more sensitive than the 51Cr release assay and makes it possible to quantitate the percentage of cell lysis and, concomitantly, to immunophenotype target cells. It also facilitates the analysis of some events of the apoptotic pathway such as caspase activation or the expression of mitochondrial molecules. This new assay should contribute to a better understanding of the mechanisms involved in cell-mediated cytotoxicity in normal and pathological situations.

Inhibition of mixed lymphocyte reactions in humans after immunization with tetanus toxoid.

Immunization of humans with tetanus toxoid (TT) results in an inhibition of the reactivity of peripheral lymphocytes to TT as well as to one-way mixed lymphocyte reaction. The strongest inhibition was observed in cells taken 3 or 7 days after immunization. These reactivities reappeared on the 14th day and reached their initial levels by the 21st day after immunization. The role of the various cell types was studied by culturing separately purified T or B lymphocytes taken on day 7 after immunization. B cells alone are not stimulated by TT or allogeneic cells. Purified T cells are stimulated much more than the initial total cell population. When B cells were mixed and cultured along with T cells, a suppressor effect upon stimulation appeared which reduced 3H-thymidine incorporation to the levels of the initial population. Treatment with 5-bromodeoxyuridine followed by exposure to light of cells stimulated with TT abrogated their ability to respond to subsequent stimulation with TT; whereas the responsiveness of treated cells to allogeneic lymphocytes was not significantly affected and vice versa. These results suggest that each stimulator activated a separate population of T cells but that in vivo immunization provoked the development of both a specific and nonspecific suppressor activity. Most probably this suppressor activity was brought about by adherent, surface Ig-bearing (B) cells.

Elderly patients treated with tinzaparin (Innohep) administered once daily (175 anti-Xa IU/kg): anti-Xa and anti-IIa activities over 10 days.

Since low molecular weight heparins (LMWH) are partly eliminated by renal excretion, their pharmacodynamic profile may be modified in very elderly patients with age-related renal impairment. The aim of this prospective study was to determine whether tinzaparin (Innohep) 175 anti-Xa IU/kg administered subcutaneously once daily over 10 days does accumulate in hospital patients greater than 70 years of age. Plasma anti-Xa and anti-IIa amidolytic levels and APTT were determined prior to the first injection (day 0), and then, at peak level i.e. 5 h after the second injection (day 2) and subsequently on days 5, 7 and 10. Thirty consecutive inpatients (6 men, 24 women) requiring LMWHs at a curative dose for acute thromboembolic disease were included. Patients' characteristics (mean +/- SD) were: age 87.0+/-5.9 years (range 71-96), body weight 62.7+/-14.6 kg (range 38-90) and creatinine clearance 40.6+/-15.3 mL/min (range 20-72). The mean actual dose of tinzaparin delivered was 174.8 anti-Xa IU/kg. Since no patient had an anti-Xa activity above 1.5 IU/mL, the dose of tinzaparin remained fixed over 10 days. Anti-Xa and anti-IIa peak levels measured on day 2 were 0.66+/-0.20 IU/mL (range 0.26-1.04) and 0.33+/-0.10 IU/mL (range 0.18-0.55), respectively. Ex vivo anti-Xa/anti-IIa ratios were close to 2.1. APTT ratios (patient/control) were strongly correlated with anti-IIa activity (p <0.01). There was no progressive increase of the anti-Xa and anti-IIa activities after repeated administration of tinzaparin over the 10 day treatment period. No correlation was found between anti-Xa and anti-IIa activities and age, weight, or creatinine clearance. No major bleeding occurred during the study and only one minor haematoma at the injection site was reported. No thrombo-embolic complication or death occurred. Tinzaparin may thus be administered safely at a treatment dose (175 anti-Xa IU/kg) in older patients with age-related renal impairment. Neither dose adjustment, nor serial anti-Xa activity monitoring seems to be required in patients with creatinine clearance above 20 mL/min during the first ten day treatment.

Potential deleterious effect of anti-viral cytotoxic lymphocyte through the CD95 (FAS/APO-1)-mediated pathway during chronic HIV infection.

The potential deleterious effect through a CD95-based pathway of anti-viral cytotoxic lymphocyte (CTL) during HIV-infection was studied. The present paper reports that a Nef specific CTL line derived from an HIV-infected person is able to kill not only Nef-expressing target cells but also CD95+ compliant Jurkat cells. The two mechanisms of cytotoxicity, i.e. perforin-vs-CD95-dependent were differentiated according to their respective Ca(2+)-dependence. The existence of the dual killing machinery in the anti-HIV CTL line was correlated with the coexpression in these cells of perforin and CD95-L molecules. A model of AIDS pathogenesis involving the deleterious effect through the CD95 pathway of the viral specific CTL response is discussed.

Two new human monoclonal antibodies against HIV type 1 glycoprotein 120: characterization and neutralizing activities against HIV type 1 strains.

Two human IgGk monoclonal antibodies (HuMAbs), termed 48-16 and 50-61A, were derived by Epstein-Barr virus transformation of B cells from two HIV-1-infected donors. These HuMAbs recognized discrete, nonoverlapping, and conformational or discontinuous epitopes on the gp120 envelope protein of HIV-1. The binding affinities of 48-16 and 50-61A for recombinant gp120 from HIV-1LAI strain, reflected by their dissociation constants, were estimated to be 2-5 x 10(-9) and 2.4 x 10(-10) M, respectively. 48-16 was shown to react with a conserved determinant present on a variety of divergent laboratory isolates, residing outside the CD4-binding site and the V3 region, which remains to be determined. 48-16 did not display, however, any detectable functional activity. 50-61A exhibited a more restricted recognition pattern, but was able to completely inhibit the 2 HIV-1 laboratory strains LAI and SF2 in a concentration range of 0.5-10 micrograms/ml, as measured by an antigen capture assay. The ability of 50-61A to block the interaction between recombinant gp120LAI and recombinant as well as cellular CD4 indicated that 50-61A epitope was localized near or within the CD4-binding side. We also demonstrated that 50-61A- and 48-16-defined epitopes (or closely related epitopes) were immunogenic in infected humans, since serum samples from 45 seropositive subjects were able to inhibit both gp120LAI-HuMAb recognitions. However, the presence of "50-61A-like" antibodies in these sera could not be associated with their neutralizing activities of HIV-1LAI infection. Interest in producing such antibodies for characterization of the human B cell repertoire to HIV-1 and their potential use in passive immunotherapy or vaccination strategy against AIDS are discussed.

Altered capillary permeability in neurogenic pulmonary oedema.

Two cases of fatal neurogenic pulmonary oedema are depicted. The hemodynamic study failed to document any hypertensive crisis or pulmonary hypertension. By contrast, the low values of pulmonary capillary wedge pressures and the high protein concentration in tracheal fluid suggest a pulmonary capillary wall lesion.

Antigen-nonspecific macrophage factors modulating the antibody response in vitro.

Antibody response to an antigen involves the co-operation between three types of cells: macrophages, T cells and B cells. The cognate interactions between these cells play a fundamental role in the expression of a specific antibody response, but the last is modulated by antigen-nonspecific soluble factors produced either by macrophages or by T cells. Macrophages elaborate a spectrum of molecules modulating the function of lymphoid cells; among them are IL1 and prostaglandins of the E series, which are respectively enhancer and inhibitor of the antibody response in vitro. These molecules alter T cell and B cell activities through different mechanisms involving activation or inhibition of IL2 production, or alteration of cells surface antigens. However, the cellular events following the fixation of soluble factor on its receptors are not known.

Oxacillin prophylaxis in cerebrospinal fluid shunt procedures: results of a randomized open study in 60 hydrocephalic patients.

A 27-month open randomized trial (October 1981-January 1984) was carried out to study the prophylactic efficacy of antibiotics in 60 hydrocephalic patients being shunted for the first time. The treatment group received oxacillin at a dosage of 200 mg/kg/day by six bolus intravenous injections, beginning with anesthetic induction and continuing for 24 hours after the operations. The minimum postoperative observation was 6 months. Six patients in the control group developed cerebrospinal fluid infections (20%) as compared with only a single patient in the oxacillin group (3.3%); this difference was statistically significant (p less than 0.05). Time of development of cerebrospinal fluid infection was brief (86% at 6 weeks), and as usual staphylococci were the pathogens most frequently implicated. This study would appear to confirm the choice of oxacillin for prevention of meningitis. Nevertheless, the frequency of methicillin-resistant staphylococci, which account for 20% of nosocomial staphylococcal infections, constitutes a limiting factor for such prevention.

[Monitoring of tinzaparin in a ten day treatment dose in elderly patients]. / Surveillance d'un traitement par la tinzaparine à dose curative pendant dix jours chez le sujet âgé.

PURPOSE: Renal impairment, which is frequently observed in elderly patients, raises the question of low molecular weight heparins treatment dose adjustment in this population. Thus, we conducted a prospective study to determine whether tinzaparin, administered subcutaneously at treatment dose (175 anti-Xa IU/kg) once daily for 10 days, does accumulate in patients older than 70 years of age. METHODS: Accumulation criteria were an increase of plasma anti-Xa and anti-IIa levels determined prior to the first injection and on days 2, 5, 7 and 10. The characteristics of the 30 consecutive included patients receiving tinzaparin at treatment dose (six men, 24 women) were: age 87.0 +/- 5.9 years (range: 71-96 years), body weight: 62.7 +/- 14.6 kg (range: 38-90 kg) and creatinine clearance 40.6 +/- 15.3 mL/min (range: 20-72 mL/min). RESULTS: None of the patients required a dose adjustment of tinzaparin over the 10-day treatment period. Anti-Xa and anti-IIa activity levels on day 2 were 0.66 +/- 0.20 IU/mL (range: 0.26-1.04 IU/mL) and 0.33 +/- 0.10 IU/mL (range: 0.18-0.55 IU/mL), respectively. These levels did not significantly change over the 10 days. These results favor the absence of the accumulation effect of tinzaparin. There was no correlation between anti-Xa and anti-IIa activities and age, weight, or creatinine clearance. Concerning the side-effects, only one minor hematoma at the injection site was reported. CONCLUSION: Tinzaparin may thus be administered in older patients with renal impairment, at a treatment dose (175 anti-Xa IU/kg/d) for a 10-day treatment period, without accumulation effect nor hemorrhagic side-effect in patients with creatinine clearance greater than 20 mL/min.

[Cerebral abscesses. Therapeutic attitude]. / Abcès cérébraux. Attitude thérapeutique.

The surgical treatment of cerebral abscesses has changed over recent years and consists, in most cases, of aspiration based on the data supplied by computerized tomography. The purpose of aspiration is threefold: to avoid a major surgical operation, to empty the abscess and thereby reduce its size, and to identify the responsible germ(s). A retrospective study of 35 cases shows that abscess of the brain remains a serious disease that jeopardizes the patient's vital and functional prognosis. Despite improvements in sample collection and isolation techniques, no microorganism is found in 30% of the cases. Therapeutic success therefore is dependent upon the effectiveness of emergency chemotherapy using combinations of two or three antibiotics. Monitoring with computerized tomography avoids unnecessarily prolonged treatments.

[Prevention of thromboembolic complications with adapted low-dose of antivitamins K after total hip prosthesis]. / Prophylaxie des complications thrombo-emboliques par antivitamines K à faible dose adaptée après prothèse totale de hanche.

This study reports the efficacy in the prevention of thromboembolic complications of adapted low-dose oral anticoagulants following total hip replacement. 750 patients undergoing total hip replacement received oral anticoagulants as exclusive drug prophylaxis for thromboembolic complications. These patients were considered preoperatively not to present any particular risk for the development of postoperative thrombosis. Anticoagulant therapy was commenced on the evening of the operation. Eleven pulmonary embolisms (1.5 per cent) were observed, but none of them were fatal. The risk of thrombosis was evaluated in 100 of these 750 patients by means of bilateral venography of the lower limbs: 21 patients developed distal thrombosis (sural veins) and 2 patients developed proximal femoral thrombosis. Only one haemorrhagic complication occurred in the 750 patients of this series. The prothrombin profile determined in the patients developing thrombosis or pulmonary embolism was not significantly different from that of the patients free of any thromboembolic complications. Although oral anticoagulants appear to be particularly effective for the prevention of fatal pulmonary embolism, it is not clear that their efficacy is directly related to the prothrombin time.

[Anterior approach to the high thoracic spine by the subscapular route]. / Abord antérieur du rachis dorsal haut par voie sous-scapulaire.

The authors report their experience of the approach of the high thoracic spine (from T1 to T3), with the help of a thoracic flap resected under the location of the scapula. This approach has only given few functional disorders after the operation: besides, it offers the possibility to widen towards the low thoracic spine or the cervical spine.

[Unilateral traumatic temporal lesions and secondary involvement of the 3d cranial nerve. Role of medical treatment]. / Lésions temporales traumatiques unilatérales et souffrance secondaire du III. La place du traitement médical.

Four cases of unilateral traumatic cerebral lesion with secondary third nerve palsy are reported. These four cases were observed over the course of one year and represent 5% of all unilateral traumatic cerebral lesion observed in our department during that period. The clinical situation presumptive of tentorial herniation included: partial (2 patients) or total (2 patients) secondary third nerve palsy, homolateral to the cerebral lesion; noncomatose state with initial Glasgow verbal score of 3 or greater; slight or no contralateral deficit. The anatomic lesions are unilateral and included 2 cases of temporal hematoma, one case of hemispheric swelling with acute subdural hematoma, and one case of general brain edema with temporal hematoma; In all 4 cases the clinical course was favorable with medical treatment alone. Based on the clinical information (non comatose state) and CT-scans (basal cisterns present or slight compressed in 3 of 4 cases), the authors believe that there was no tentorial herniation; third nerve palsy occurred without axial compression. The authors analysed several of the accepted criteria for severe head injuries (GCS, CT-scan, and ICP) and referred to the literature in order to determine optimal patient management in such reversible situations that posed a danger of tentorial herniation. Repeated clinical examination and CT-scan for visualization of basal cisterns appeared to be the best criteria for therapeutic decision.

[Thrombophlebitis of the superior longitudinal sinus in the surgical stage. Apropos of a case. Value of low-molecular weight heparin]. / Thrombophlébite du sinus longitudinal supérieur au stade chirurgical. A propos d'un cas. Intérêt de l'héparine de bas poids moléculaire.

A case of superior sagittal sinus thrombosis is reported. The patient was a 27 years women and thrombosis occurred at 5 weeks pregnancy. This patient had one antithrombin III deficiency. Neurological feature associated hemiplegia and comatose with signs of severe intracranial hypertension (intracranial pressure greater than 50 mmHg). CT scan showed hemorrhagic infarct with man effect (real intracranial hematoma). This case was successful treated by surgical removal and low molecular weight heparin as anticoagulant. The patient recovered rapidly and kept only a slight focal deficit.