Light Conversion by Electrochemiluminescence at Semiconductor Surfaces.

ConspectusElectrochemiluminescence (ECL) is the electrochemical generation of light. It involves an interfacial charge transfer that produces the excited state of a luminophore at the electrode surface. ECL is a powerful readout method that is widely employed for immunoassays and clinical diagnostics and is progressively evolving into a microscopy technique. On the other hand, photoelectrochemistry at illuminated semiconductors is a field of research that deals with the transfer of photogenerated charge carriers at the solid-liquid interface. This concept offers several advantages such as a considerable lowering of the onset potential required for triggering an electrochemical reaction as well as light addressable chemistry, via the spatial confinement of redox reactions at locally illuminated semiconductor electrodes. The combination of ECL with photoelectrochemistry at illuminated semiconductors is termed photoinduced ECL (PECL). It deals with the triggering of an ECL reaction through the transfer of photogenerated minority charge carriers at the illuminated solid/liquid interface. PECL results in the conversion of incident photons (λexc), that are absorbed by the semiconductor photoelectrode to emitted photons (λPECL), produced by the ECL reaction. Although demonstrated in the 1970s by Bard et al. in ultradry organic solvents, PECL remained unexplored until the last five years. Nowadays, as a result of the considerable progress achieved in semiconductor photoelectrodes and ECL systems, a large variety of PECL systems can be designed by combining photoelectrode materials with ECL luminophores, making it a versatile tool for light conversion in aqueous media.In this Account, we introduce the fundamentals of ECL and photoelectrochemistry at illuminated semiconductors and review the recent developments in PECL. We discuss the two main PECL light conversion schemes: downconversion (where λexc < λPECL) and upconversion (where λexc > λPECL). Besides, PECL can be used to simplify considerably the common electrochemical setups employed for ECL. Indeed, by engineering the photoelectrode material and carefully considering the reactivity involved for ECL and its counter-reaction, PECL enables the ultimate concept of all-optical ECL (AO-ECL), i.e., ECL generation at an illuminated monolithic device immersed into the electrolyte solution. As discussed in this Account, AO-ECL is an important breakthrough that allows the simplest ECL experimental configuration ever reported, eliminating constraints such as an electrical power supply, wires, electrodes, connections, and specific electrochemical knowledge. As shown at the end of this Account, due to the robustness of recently manufactured PECL systems, several applications can already be envisioned for microscopy, elucidation of solar conversion mechanisms, near-infrared imaging, and bioanalysis.

Ultrasound-guided transection of the interosseous membrane of the forearm.

We sought to evaluate the feasibility of ultrasound-guided transection of the interosseous membrane of the forearm. The study involved ten forearms from five fresh cadavers. An ultrasound scanner (Toshiba™ Aplio V®, Toshigi, Japan) with a linear probe (Toshiba™ PLT-805AT 8Mhz) and a 25-cm long Kemis® knife (NewClip Technics™, Cholet, France), which was specially created for this study, were used. An approach to the distal and proximal radioulnar joint was made before the transection. The induced muscle hernia sign and the radius joystick test were performed to confirm the effectiveness of the ultrasound-guided transection. Complete dissection of the posterior surface of the forearm was done to check for complications and evaluate the quality of the transection. We registered nine complete transections of the interosseous membrane. The muscular hernia sign was present in all the cases performed. The joystick test was positive in eight cases. One forearm had a vascular complication. This ultrasound-guided interosseous membrane transection technique is feasible and effective with limited vascular and nerve risks. A prospective clinical study is required to validate this anatomical work.

In search of acceptable alternatives to the murine histamine sensitisation test (HIST): what is possible and practical?

The 'International Workshop on Alternatives to the Murine Histamine Sensitization Test for Acellular Pertussis Vaccines: In Search of Acceptable Alternatives to the Murine Histamine Sensitization Test (HIST): What is Possible and Practical?' was held on 4 and 5 March 2015 in London, United Kingdom. Participants discussed the results of the data generated from an international collaborative study (BSP114 Phase 2) sponsored by the European Directorate for the Quality of Medicines & Health Care (EDQM) to determine if a modified Chinese hamster ovary (CHO) cell-based clustering assay is a suitable alternative to replace HIST. Workshop participants agreed that protocol transferability demonstrated in the collaborative study indicates that a standardised CHO cell assay is adequate for measuring pure PTx in reference preparations. However, vaccine manufacturers would still need to demonstrate that the method is valid to detect or measure residual PTx in their specific adjuvanted products. The 2 modified CHO cell protocols included in the study (the Direct and the Indirect Methods) deserve further consideration as alternatives to HIST. Using the CHO cell assay, an in vitro alternative, for acellular pertussis (aP) vaccine batch release testing would reduce the number of animals used for aP vaccine safety testing. A strategic, stepwise adoption plan was proposed, in which the alternative test would be used for release purposes first, and then, once sufficient confidence in its suitable performance has been gained, its use would be extended to stability testing.

Role of safety-engineered devices in preventing needlestick injuries in 32 French hospitals.

OBJECTIVES: To evaluate safety-engineered devices (SEDs) with respect to their effectiveness in preventing needlestick injuries (NSIs) in healthcare settings and their importance among other preventive measures. DESIGN: Multicenter prospective survey with a 1-year follow-up period during which all incident NSIs and their circumstances were reported. Data were prospectively collected during a 12-month period from April 1999 through March 2000. The procedures for which the risk of NSI was high were also reported 1 week per quarter to estimate procedure-specific NSI rates. Device types were documented. Because SEDs were not in use when a similar survey was conducted in 1990, their impact was also evaluated by comparing findings from the recent and previous surveys. SETTING: A total of 102 medical units from 32 hospitals in France. PARTICIPANTS: A total of 1,506 nurses in medical or intensive care units. RESULTS: A total of 110 NSIs occurring during at-risk procedures performed by nurses were documented. According to data from the 2000 survey, use of SEDs during phlebotomy procedures was associated with a 74% lower risk (P<.01). The mean NSI rate for all relevant nursing procedures was estimated to be 4.72 cases per 100,000 procedures, for a 75% decrease since 1990 (P<.01); however, the decrease in NSI rates varied considerably according to procedure type. Between 1990 and 2000, decreases in the NSI rates for each procedure were strongly correlated with increases in the frequency of SED use (r=0.88; P<.02). CONCLUSION: In this French hospital network, the use of SEDs was associated with a significantly lower NSI rate and was probably the most important preventive factor.

Improved storage of erythrocytes by prior leukodepletion: flow cytometric evaluation of stored erythrocytes.

In vivo phagocytosis of senescent red blood cells (RBCs) by macrophages occurs 120 days after their release into the circulation. It depends on two sequential signals that trigger phagocytosis: (1) desialylation of membrane glycoconjugates with the exposure of the penultimate beta-galactosyl residues and (2) exposure of phosphatidylserine in the membrane outer leaflet. Leukodepleted and nonleukodepleted RBCs were compared using flow cytometric procedures to determine whether the in vitro deterioration of RBCs during storage might be attributable to an identical mechanism of desialylation induced by leukocyte neuraminidases, resulting in exposure of beta-galactosyl and subsequently phosphatidylserine residues - signals of senescent RBCs. Without prior leukodepletion, stored RBCs showed an increased population of senescent RBCs (using light scatter measurements), extensive desialylation with the exposure of beta-galactosyl residues (using specific fluorescein isothiocyanate [FITC]-lectins), significant exposure of phosphatidylserine in the outer leaflet of the RBC membrane (using FITC-annexin V), and extensive in vitro phagocytosis (using PKH-26-labeled RBCs). There were minimal changes observed with the leukodepleted RBCs. These results lead to the conclusion that leukocyte enzymes, including neuraminidases, are definitive contributers to the desialylation of RBCs during storage and to the exposure of phosphatidylserine residues. These deleterious effects resulting from highly active leukocyte enzymes are preventable by prior leukodepletion of the stored RBCs. Previously developed flow cytometric procedures to detect in vivo "RBC senescence" have been applied and proved to be reliable criteria to monitor the viability of stored RBCs.

[Outcome of patients with systemic rheumatic diseases admitted to intensive care units: a retrospective study of 39 cases]. / Pronostic des maladies systémiques admises en réanimation: étude rétrospective de 39 séjours.

PURPOSE: Patients with systemic rheumatic diseases are rarely admitted in intensive care units and very few studies focusing on the prognosis of those patients have been published. METHODS: Retrospective study over seven years in two intensive care units. RESULTS: Among 33 patients with systemic disease diagnosed 90 +/- 133 months before admission in the intensive care unit, who were aged 50 +/- 21 years and represented a total of 39 stays in the intensive care unit, the main cause of admission was acute respiratory failure (33%). Mean simplified acute physiology score (SAPS II) was 47 +/- 22. Two-thirds of the patients were under mechanical ventilation. Infection was diagnosed in 33% of the cases and exacerbation of the systemic rheumatic disease in 26%. Nosocomial infection was found in 19 patients (49%). Ten patients died during their stay in the intensive care unit, six from infection, three from an exacerbation of the systemic rheumatic disease, one from an unidentified cause. CONCLUSION: Even if severity scores of patients suffering from systemic diseases are higher at admission in intensive care units than those of other patients, there is no relevant reason to refuse critical care to these patients.

Purification of human ceruloplasmin as a by-product of C1-inhibitor.

Human ceruloplasmin (Cp) has been purified from cryoprecipitate-poor plasma as a by-product of the C1-inhibitor production chain. Highly purified Cp was obtained by subsequent ion-exchange chromatography on sulfate-Fractogel EMD and TMAE-Fractogel EMD. Treatments for viral safety included application of the solvent-detergent method and two nanofiltration steps using 35- and 15-nm pore size filters at the end of the process. Overall antigen yield was 95 (+/-5) %. Purified human ceruloplasmin was studied by electron spin resonance (ESR) to characterize its different types of copper complexes and to check its antioxidant properties. We distinguished three types of complexes: one type-2 Cu(II) with g// = 2.25 and A// = 180 G and two type-I Cu(II) exhibiting different narrow hyperfine splitting (A// = 72 G and A// = 90 G) with close g// (2.20 and 2.21). Purified Cp has a specific activity of 24.5+/-0.2 mU/mg of proteins. This process provides a method for Cp purification that could be easily integrated into modern plasma fractionation.

Release potency tests of hepatitis vaccines.

SmithKline Beecham Biologicals produces two vaccines against hepatitis: hepatitis B (Engerix-B) introduced in 1986 and hepatitis A (Havrix) introduced in 1991. Using these two examples, we demonstrate the long and gradual transition process towards an in vitro release test for potency and a significant decrease in the number of animals needed for vaccine release.

[Therapeutic applications of genetic engineering]. / Applications thérapeutiques du génie génétique.

Technical developments of genetic engineering have been revealed especially interesting in the human therapeutic field. Techniques for gene transfer have been improved to introduce synthetic sequences into the cellular genomes. Candidate cells and culture systems have been screened for their capacity to synthesise the proper recombinant molecules. In the nearest future, high biotechnologies should provide a great quantity of recombinant products, covering a high variety of diseases (clotting factors, cytokines, hormones, monoclonal antibodies, vaccines, thrombolytics). This tendency has been largely initiated, and is accompanied by the quick development of basic sciences such as glycobiology and molecular biology, together with the development of a specific regulatory environment. Besides, genetic engineering offers new therapeutic outlets: transgenic animals, genic therapy, antisense technology.

Iodine-123-labelled serum amyloid P component scintigraphy in amyloidosis.

This study describes the results of scintigraphy with iodine-123-labelled serum amyloid P component (SAP) as a means of establishing the distribution of organ involvement in amyloidosis. The significance of 123I-SAP scans obtained in 15 patients with biopsy-proven AA or AL amyloidosis is discussed. Biopsy-proven amyloidosis was typically confirmed by scintigraphy, though such confirmation was not obtained in the kidneys in six patients with histological proof of extensive renal amyloid deposition. This lack of uptake may have been due to the accumulation of a major part of the 123I-SAP in the spleen and/or liver. Twenty-four hour whole-body retention of 123I-SAP was higher in patients with amyloidosis than in controls. Twenty-four hour tracer accumulation of the radioactivity in the extravascular compartment was notably greater in patients than in controls and appeared to be a good diagnostic criterion. We conclude that 123I-SAP scintigraphy may be helpful for the evaluation of organ involvement not only in patients with biopsy-proven amyloidosis but also when a biopsy cannot be performed or when a strong suspicion of amyloidosis exists in spite of repeated negative biopsies.

[Occupational risk of exposure to blood in nurses. Results of a one-year monitoring of the risk for nurses in 17 hospitals]. / Exposition accidentelle au sang du personnel soignant. Résultats d'un an de surveillance du risque pour les infirmières dans 17 hôpitaux.

To evaluate the incidence of risk factors for exposure of health care providers to patients' blood, a prospective multicenter study was carried out in 1990 in 17 hospitals in continental France. 521 nurses from 20 departments of medicine and 9 intensive care nurses participated in the study. Trained investigators documented exposures to blood using a standardized questionnaire and carried out monthly 24 hours cross-sectional surveys to determine the number of high risk procedures performed on a given day. One hundred and eighty-three exposures to blood were documented, for an incidence of 0.35/nurse/year. Needle-stick injuries were the most common events (75%). Exposure to blood occurred during a sampling procedure in 48% of cases, an infusion-related procedure in 20% of cases, and an injection in 17% of cases. Comparisons of rates of procedures associated with needle-stick injuries and of procedures performed during a typical day demonstrated differences in the magnitude of the risk associated with each procedure: infusion-related procedures carried the greatest risk, followed by venous blood sampling procedures. Sixty-four percent of exposures to blood occurred after completion of the procedure. Forty-nine percent of documented exposures to blood would probably not have occurred if universal infection control recommendations (CDC, DGS) had been implemented. Twenty-seven percent of exposures to blood involved HIV-positive patients, who accounted for only 7% of patients managed in the participating centers during the study period.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of an atrophic rhinitis vaccine under controlled conditions.

A vaccine containing inactivated cultures of Bordetella bronchiseptica, toxigenic Pasteurella multocida type D and dermonecrotic P multocida type D toxoid in an oil-in-water adjuvant was given to seven sows, with seven others acting as controls. Half the piglets in each litter were exposed intranasally when four days old to B bronchiseptica and when eight days old to toxigenic P multocida type D. There was considerably less sneezing in the litters of the vaccinated sows and when the piglets were 10 weeks old, only 18 per cent had deformed snouts compared with 74 per cent in the litters of the control sows. The average liveweight gain of the piglets born to vaccinated sows was significantly better (P less than 0.05) between two and 10 weeks of age than that of the piglets born to unvaccinated sows, although there were no significant lower respiratory tract lesions in either group. The conchal atrophy scores were significantly lower (P less than 0.001) in the piglets from the vaccinated sows and were negatively correlated (r = -0.37) with increasing liveweight gain. In the liters of the vaccinated sows, P multocida was not isolated from the nasal passages of the in-contact piglets and from only 7 per cent of those deliberately exposed compared with 65 per cent and 79 per cent, respectively, in the litters of the control sows. P multocida was isolated post mortem from the tonsils of 23 per cent of the piglets of vaccinated sows and from 87 per cent of those from unvaccinated sows.

Quantification of serum amyloid P by enzyme-linked immunosorbent assay.

This enzyme-linked immunosorbent assay procedure for quantifying serum amyloid P (SAP) in human plasma makes use of affinity-purified polyclonal antibodies to SAP in a "sandwich"-type format. The procedure is sensitive, reproducible, simple, and easily automatable. Results correlate well with those by a rocket immunoelectrophoresis method performed with the same antibodies. Sera from apparently normal individuals had a mean SAP content of 44.17 mg/L and increased with age.

Prevalence of Leptospira interrogans serovar hardjo antibodies in milk in Belgian dairy herds.

Pooled milk samples were collected from 2000 Belgian dairy herds in the autumn of 1989. Antibodies against Leptospira interrogans serovar hardjo were detected in 9.2% of the herds, with the incidence being higher in the southern part of the country.

Hemoglobin Calais [beta 76 (E20) Ala----Pro]: a hemoglobin variant with decreased intrinsic oxygen affinity.

Hb Calais [beta 76 (E20) Ala----Pro] is a new human hemoglobin variant displaying a decreased oxygen affinity. The only electrophoretical difference with Hb A was a slightly more acidic isoelectric point. A 2-fold decrease in the oxygen affinity was found by equilibrium measurements performed in a suspension of intact red blood cells and in the lysate. It was confirmed by kinetic studies of the purified abnormal hemoglobin. The rate of methemoglobin formation at 37 degrees C of Hb Calais was also increased relative to Hb A. The mechanism by which the Pro for Ala substitution of an external residue in the beta-chains results in these profound functional abnormalities is unclear. Subtle changes at the heme pocket, at a distance from the mutation, may be a plausible explanation for the effects observed.

Stimulation of peripheral blood lymphocytes of HIV-infected patients by jacalin, a lectin mitogenic for human CD4+ lymphocytes.

The proliferative response of peripheral blood mononuclear cells stimulated by jacalin was investigated in 157 samples from 104 HIV-infected patients at various clinical stages of disease. Jacalin proliferative response correlated with the absolute numbers and percentages of CD4+ lymphocytes and with the percentages of Leu 8 lymphocytes. It correlated negatively with the percentages of CD8+ and CD38+ lymphocytes. It was depressed during acute HIV infection and at advanced stages. The response in Centers for Disease Control groups II and III was heterogeneous and similar; in both, some patients showed a very low response. Further follow-up of the present patients should indicate whether jacalin responsiveness has a prognostic value.