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To explore the expressions of miR-132 in patients with chronic hepatitis B, posthepatitic cirrhosis and hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC), and to investigate its possible mechanism affecting the function of the body.Among 125 patients with HBV, there were 44 cases of chronic hepatitis, 42 cases of liver cirrhosis and 39 cases of liver cancer. Their liver function and HBV-deoxyribonucleic acid (HBV-DNA) viral load as well as the expressions of micro ribonucleic acid-132 (miR-132), phosphoinositide 3-kinase (PI3K), phosphorylated-protein kinase B (p-Akt) and hepatitis B X protein (HBx), were detected.There were significant differences in some liver function indexes and the HBV-DNA level among the three groups of patients (p0.05). The HBV-DNA level was 6.91 Lg copies/mL in the liver cancer group and 5.34 Lg copies/mL in the chronic hepatitis B group. Differences in the expression level of miR-132 among the three groups were notable (p0.05), but this expression level had a negative correlation with the HBV-DNA level. The expressions of PI3K and p-Akt proteins and messenger ribonucleic acids (mRNAs) were markedly different among the three groups (p0.05). HBx was expressed in the three groups of patients, and liver cancer patients with the highest expression degree of HBx accounted for 46%.Differences in the expression of miR-132 among the three groups are evident, which may be associated with differences in liver function, the HBV-DNA level, HBx and the expressions of PI3K and p-Akt proteins to a certain degree.

To ensure product quality, the inspection and analysis were carried out on the ultra high-strength steel welded shell with transverse rupture after qualified hydraulic blasting test. Firstly, we carried out spot investigation of hydraulic blasting test, breakage morphological analysis, investigation on production technology, reexamination of wall-thickness and X-ray film of welding joint; in case of different opinions on fast analysis, then, we carried out contrast detection and analysis on stripe of fracture, metallographic analysis on cross section of welding joint, TEM detection and analysis on fracture, and inspection and analysis on welding size and offset. The analysis results showed that, the transverse rupture of test sample after hydraulic blasting test was caused by the failure of part incomplete joint penetration on welding joint, which was due to welding arc deviation. Therefore, with the improvements of welding equipments, tooling and operation methods to prevent radial and weld offset, the welding quality was assured and improved.

Tungsten oxide (WO3) films have been prepared on ITO glass substrates via sol–gel method using polyethylene glycol (PEG) as organic template. The influence of PEG additive and annealing technique on microtopography and electrochromic properties has been studied. Moreover, the reaction process and electrochromic mechanism were discussed. The results showed that the properties of pure WO3 films were improved by PEG doping, which facilitates ions transport in the films. The films derived from the sol with PEG annealed at 300°C and heating rate of 0·5°C min−1 exhibit superior microtopography and electrochromic property compared to the films obtained from pure WO3 sol. The ion storage capacity of the films obtained with faster heating rate decreased obviously within 140 colour-bleach cycles, accordingly the films with slower heating rate sustains 200 cycles without significant degradation implies the improvement of cycle life.

Power transmission systems are being operated closer to their stability limits compared to twenty years ago. As a result, an increasing risk of blackouts combined with extremely high costs economically and socially is observed. To reduce this risk the personnel in the control rooms of the transmission system operators have to be assisted by a system, which assesses the dynamic state of security online. The system presented in this paper is designed to investigate the security with regards to voltage stability, transient stability and small signal oscillatory stability. New technologies of visualizing the degree of stability to non dynamic stability experts are used as well as integration in existing SCADA/EMS systems are realized. The performance of the system is sufficiently high to be employed in the online environment of the control room.

New strategies and methods for assessing the security of protection systems to reduce the risk of unnecessary disturbances and blackouts are the main topic of the present paper. The system behavior of a protection system and network is analyzed and assessed as a whole. Hence, the established algorithms are capable to handle complex network structures with regard to an intelligent data management as well as data validation. Protection security assessment comprised two different aspects: on the one hand the behavior regarding dependability and security in terms of speed and sensitivity, on the other hand the behavior regarding the response on dynamic network phenomena as voltage stability and transient stability. A new automated method for assessing the dependability and security of protection systems is shown. The short-circuit simulation tool is used to provide a simulation system including network and protection devices as a whole. The handling of the large amount of resulting data is done by an intelligent visualization method like a “fingerprint” analysis. Further on the paper is focused on the protection response on dynamic network phenomena and presents innovative strategies for this investigation aspect. The structure of simulation environment will be described. Results of a case study show the application of this method on a real network. The system tool which is concluding these two aspects of protection assessment is called SIGUARD? PSA.

Significant advances in microwave and millimeter wave technology over the past decade have enabled the development of a new generation of imaging diagnostics for current and envisioned magnetic fusion devices. Prominent among these are microwave electron cyclotron emission imaging, microwave phase imaging interferometers, imaging microwave scattering, and microwave imaging reflectometer systems for imaging Te and ne fluctuations (both turbulent and coherent) and profiles (including transport barriers) on toroidal devices such as tokamaks, spherical tori, and stellarators. The diagnostic technology is reviewed, and typical diagnostic systems are analyzed. Representative experimental results obtained with these novel diagnostic systems are also presented.

Resonant frequencies and unloaded Q's of hybrid modes on cylindrical dielectric resonators in conducting enclosures are studied. The formulation uses the mode matching technique, and includes axially symmetric (TE0m and/or TM0m), as well as axially non-symmetric hybrid (HEnm,) modes which could exist in dielectric loaded waveguides. The structures analyzed can simulate resonators on ground plane backed or suspended substrates. Losses in the conducting walls, substrates, and the dielectric material, and stored energy in the general resonator are obtained. Mode amplitudes determined from the solution of the boundary value problem by mode matching are used to rigorously compute the unloaded Q's of the resonators. Numerical results in the millimeter wave range and in C-band are presented. These results include unloaded Q's and mode charts of dielectric resonators on ground plane backed and suspended substrate structures. From these results, methods for improving the unloaded Q's and mode's separation are expl...

Summary form only given. An exciting tool for the study and visualization of plasma turbulence is presently under development for the TEXTOR-94 tokamak. This system combines a high resolution electron cyclotron emission imaging (ECEI) diagnostic with an innovative microwave imaging reflectometer (MIR) diagnostic for the simultaneous localized measurement of electron temperature T. and electron density n/sub e/ fluctuations in the tokamak core. The ECEI diagnostic images second harmonic cyclotron radiation from the optically thick plasma onto a 1-D array, thereby forming an image of the T/sub e/ profile and fluctuations associated with the emission layer. The MIR diagnostic images radiation reflected from the plasma cutoff layer onto a similar 1-D array, thus forming an image of n/sub e/ fluctuations at the reflecting layer. Both diagnostics are capable of forming 2-D images of plasma turbulence by varying the frequency of the probing (for MIR) or received (for ECEI) signals. Adjustment of the reflectometer probing frequency permits the reflecting layer to be positioned coincident with the ECEI emission layer, thereby simultaneously sampling both T/sub e/ and n/sub e/ fluctuations over an extended surface of the TEXTOR-94 plasma. Such data will permit the visualization of complicated 2-D and/or 3-D structures which is essential for definitive comparisons to be made with the predictions of gyrokinetic computer simulations. In addition, the system will also be employed in the study of a number of MM phenomena such as plasma filament formation, magnetic islands and internal transport barriers. An overview of the simultaneous imaging diagnostic concept will be presented along with technical details and characterization measurements of the TEXTOR-94 diagnostic. The system is presently under fabrication, and will begin operation in August, 2002 when TEXTOR-94 resumes operation after the installation of a dynamic ergodic divertor.

Properties of the TE/sub 02/ higher order mode of a sapphire dielectric resonator are investigated. This mode has significantly higher unloaded quality factor Q than that of the TE/sub 01/ mode. A significant reduction of the losses and corresponding increases in the unloaded Q of the resonator can be achieved by using superconductor enclosure covers. Detailed accurate quantitative analysis and results showing the improvements are presented. This resonator can be used in very-low-phase-noise oscillator applications. >

It is shown that with high-quality, large-area YBCO films and simple, styrofoam mounts, unloaded X-band Q values of over 250 thousand are attainable for TE/sub 01/ mode operation of a sapphire dielectric resonator (DR) operated at 77 K and employing high-temperature superconducting (HTS) films installed in the DR enclosure covers. Rigorous analysis for the determination of resonator frequency, modes, and unloaded Q have been carried out using mode matching techniques. The results of both analysis and prototype device evaluation experiments are compared for resonators fabricated using enclosures consisting of conventional metal sidewalls and covers using HTS films as a function of cover conductivity. >

Significant advances in microwave and millimeter wave technology over the past decade have enabled the development of a new generation of imaging diagnostics for current and envisioned magnetic fusion devices. Prominent among these are revolutionary microwave electron cyclotron emission imaging (ECEI), microwave phase imaging interferometers, imaging microwave scattering and microwave imaging reflectometer (MIR) systems for imaging electron temperature and electron density fluctuations (both turbulent and coherent) and profiles (including transport barriers) on toroidal devices such as tokamaks, spherical tori, and stellarators. The diagnostic technology is reviewed, and typical diagnostic systems are analyzed. Representative experimental results obtained with these novel diagnostic systems are also presented.

The anomalous transport in magnetized plasmas remains to be an outstanding issue, which in large part due to the difficulty in diagnosing the small amplitude fluctuations in the high temperature plasma core1. Recent progress in fusion studies has motivated the development of advanced microwave imaging diagnostics, both to visualize the elegant three-dimensional (3-D) structures of plasma turbulence revealed by extensive computer simulations2 and to perform high spatial and temporal resolution measurement of turbulent fluctuations in the plasma core, such as Te fluctuation measurements by ECE imaging. A third motivation is the recent discovery of the problem with conventional reflectometry and the need for imaging reflectometry as an essential tool for density fluctuation measurements3. The fourth is the need to measure fine scale structures in profiles of transport significance, such as filamentation and internal transport barriers4. The focus and emphasis of this paper will therefore primarily be on the dramatic breakthroughs occurring in electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR), which will ultimately permit the imaging and visualization of complicated 2-D and 3-D structures of both electron temperature and density.

Ultra-high Q, X-band resonators, used in a frequency discriminator for stabilization of a low-noise signal generator, can provide a means of obtaining significant reduction in phase noise levels. Resonator unloaded Qs on the order of 500 K can be obtained in sapphire dielectric resonator (DR) operating on a low-order (i.e. TE/sub 01/) mode at 77 K and employing high-temperature superconducting (HTS) films installed in the DR enclosure covers. Rigorous analysis for the determination of resonator frequency, modes, and unloaded Q have been carried out using mode matching techniques. Trade-off studies have been performed to select resonator dimensions for the optimum mode yielding highest unloaded Q and widest spurious mode separation. Field distributions within the resonator have been computed to enable practical excitation of the required mode. The results of both analysis and prototype device evaluation experiments are compared for resonators fabricated using enclosures consisting of conventional, metal sidewalls and covers employing HTS films as a function of cover conductivity. >

An n-ZnO/p-ZnO : Sb homojunction light emitting diode was fabricated on c-plane sapphire by metal–organic chemical vapour deposition (MOCVD). The p-type ZnO layer with a hole concentration of 1.27 × 1017 cm−3 was fabricated using trimethylantimony (TMSb) as the Sb doping source. The current–voltage characteristics of the device exhibited a desirable rectifying behaviour with a turn-on voltage of 3.3 V. Distinct electroluminescence with ultraviolet and visible emissions was detected from this device under forward bias at room temperature. Moreover, metal–organic source TMSb is an effective and controllable dopant in the MOCVD technique, which is suitable for further industrialized production.

ZnO homojunction light-emitting diode with n-ZnO∕p-ZnO:As∕GaAs structure is produced by metal organic chemical vapor deposition. The p-type ZnO:As film is obtained out of thermal diffusion of arsenic from GaAs substrate with subsequent thermal annealing at 550°C. The n-type layer is composed of unintentionally doped ZnO film. Desirable rectifying behavior is observed from the current-voltage curve of the ZnO p-n homojunction. Furthermore, two distinct electroluminescence bands centered at 3.2 and 2.5eV are obtained from the junction under forward bias at room temperature.

Cholera toxin (CT), either mixed with or conjugated to unrelated protein Ag, is known to enhance the intestinal IgA response of rodents toward the unrelated Ag. Although relatively low doses of CT exert this gut mucosal adjuvant effect, the inherent toxicity of CT is a hindrance to its use in humans. Our report demonstrates that CT treated with 20 mM glutaraldehyde retains adjuvant properties but exhibits more than 1000-fold lower toxicity than untreated toxin. Glutaraldehyde was also used in a one-stage conjugation procedure to couple CT covalently to Sendai virus. Again, toxicity was reduced more than 1000-fold. This drop in toxicity is consistent with an observed 100-fold loss in binding capacity of the CT B subunit and a 20- to 50-fold reduction in adenylate cyclase activation by the CT A subunit. Oral administration of this virus-toxoid conjugate resulted in increased gut antiviral IgA titers compared with oral administration of either virus alone or of virus mixed with glutaraldehyde-treated toxin. This marked decrease in toxicity may afford a practical approach for the use of CT as a mucosal adjuvant.

Both nonlabeled and radiolabeled IgA mAb with specificity toward Sendai virus, a respiratory pathogen, were used to investigate the transport of serum polymeric and monomeric IgA into murine upper and lower respiratory secretions as well as into the gut. After purification by affinity chromatography, IgA mAb were fractionated into monomers and polymers by gel filtration and radiolabeled with 125I. Mice were injected i.v. with either 125I-monomer and 131I-albumin or 125I-polymer and 161I-albumin. At various times after injection, serum and gut, nasal and bronchoalveolar lavage samples were collected. The TCA precipitable radioactivities were determined and the selective transport indices calculated. The results indicated selective transport of polymeric IgA but not monomeric IgA from serum into upper respiratory and intestinal secretions. The degree of TCA precipitability in nasal lavage and to a lesser extent gut secretions suggested significant degradation of the antibody during or after transport. To investigate further the integrity of the IgA in mucosal secretions, ELISA viral binding activity of nonradiolabeled IgA was determined for both IgA incubated with nasal secretions in vitro and polymeric IgA recovered by nasal lavage 4 h after i.v. injection. Although reconstitution experiments indicated no significant loss of antibody binding activity after incubation of antibody with lavage fluid in vitro, only negligible ELISA binding activity was detected in nasal washes after i.v. injection of antibody. The data overall suggest that although there is a quantitatively small, but selective transport of polymeric IgA into the upper respiratory tract, this transport results in minimal functional antibody activity. Implications of these and other findings for strategies of oral immunization in prophylaxis against respiratory infections are discussed.

Based on the concept of a common mucosal immune system wherein mucosal associated lymphocytes traffic among the various mucous membranes, the murine gastrointestinal tract was immunized with Sendai virus antigens in order to elicit a virus-specific immune response in the respiratory tract. Multiple intragastric (oral) administration of live or killed Sendai virus induced IgA and IgG antiviral antibodies in both gastrointestinal secretions and serum. When cholera toxin as an adjuvant was included along with virus, gut IgA and IgG as well as serum IgA responses were enhanced. Antiviral antibodies induced in respiratory secretions by oral killed virus plus cholera toxin, however, were variable and protection from virus challenge was not demonstrated. Significantly higher levels of respiratory antiviral antibodies were induced if immunization with oral killed Sendai virus/cholera toxin was combined with intranasal administration of small amounts of killed virus. The combined immunization also resulted in protection of both the upper and lower respiratory tracts from virus infection. Protection of the upper respiratory tract was correlated with the presence of IgA antiviral antibodies in nasal washings. On the other hand, protection of the lower respiratory tract was correlated with IgG antiviral antibodies in bronchoalveolar lavage fluids. Immunization with intranasal killed virus alone conferred partial protection to the lower respiratory tract and no protection to the upper respiratory tract. Thus, oral immunization with killed virus antigen could prime for a protective immune response in the murine respiratory tract and this protective response included IgA antibodies.

Successful oral immunization to prevent infectious diseases in the gastrointestinal tract as well as distant mucosal tissues may depend on the effectiveness of an Ag to induce gut immune responses. We and others have previously reported that cholera toxin possesses strong adjuvant effects on the gut immune response to co-administered Ag. To explore further adjuvant effects of cholera toxin, the holotoxin or its B subunit was chemically cross-linked to Sendai virus. The resulting conjugates, which were not infectious, were evaluated for their capacity to induce gut immune responses against Sendai virus after oral administration to mice. Conjugating cholera toxin to virus significantly enhanced the adjuvant activity of cholera toxin compared to simple mixing. Cholera toxin B subunit, however, did not show an adjuvant effect either by itself or conjugated with the virus. Oral administration of the Sendai virus-cholera toxin conjugate was also able to prime for protective anti-viral responses in the respiratory tract. Mice that were orally immunized with the conjugate and intra-nasally boosted with inactivated virus alone showed virus-specific IgA titers in nasal secretions that correlated with protection against direct nasal challenge with live Sendai virus. For comparison, s.c. immunization was also studied. Systemic immunization with the virus-cholera toxin conjugate induced virus-specific antibody responses in serum as well as in the respiratory tract but failed to protect the upper respiratory tract against virus challenge. Systemic immunization plus an intra-nasal boost did, however, confer a variable degree of protection to the upper respiratory tract, which correlated primarily with bronchoalveolar lavage (lung) antibody titers.

The analysis and characterization of corrugated periodic structures in dielectric loaded waveguides are presented. The Floquet theorem and mode-matching techniques are used to perform the analysis. The characteristic equation, which gives the dispersion relation for the periodic structure, is derived. Phase and group velocities of waves on these periodic structures are then obtained from the dispersion curves. These results have potential applications as slow wave structures for traveling-wave tubes and possible filtering structures at millimeter-wave frequencies. >

We have sought to exploit the common mucosal immune system in order to achieve effective respiratory immunity following oral, i.e., gastrointestinal, immunization. The concept of a common mucosal immune system is embodied in the observation that IgA B lymphocytes initially encountering antigen at one mucous membrane can, during their differentiation toward IgA-secreting plasma cells, migrate to other mucous membranes distant from the site of initial antigenic stimulation (Rudzik et al. 1975; Weisz-Carrington et al. 1979). Although antigen is not required for this homing of IgA plasma cell precursors to distant mucous membranes, it has been shown, for example, that antigen applied to the respiratory tract can enhance the number of IgA-bearing, antigen-specific lymphocytes which accumulate in the respiratory tract of orally or enterically primed rodents (Pierce and Cray 1981; Weisz-Carrington et al. 1987). The model system we are using is Sendai virus infection of mice. Sendai virus, a parainfluenza type 1 virus related to human respiratory pathogens, naturally infects mice and can cause a wide spectrum of disease ranging from relatively mild upper respiratory infection to lethal viral pneumonia.

Cholera toxin was investigated as an adjuvant for anti-virus antibody responses in the respiratory mucosa of mice. Two methods of applying cholera toxin were evaluated: oral administration and intranasal administration. Oral immunization with Sendai virus in the presence of cholera toxin effectively primed for respiratory anti-viral antibody responses, whereas oral immunization with Sendai virus alone was ineffective in this respect. In nasal washes, IgA was the predominant anti-viral antibody enhanced by oral cholera toxin; in bronchoalveolar washes, the enhanced anti-viral antibodies included IgG, IgA, and IgM. Effects of direct administration of cholera toxin to the respiratory mucosa on respiratory anti-viral antibody responses depended on the method of anesthesia used during immunization. With inhalation anesthesia (ether), cholera toxin had no adjuvant effect on respiratory antibody responses to coadministered Sendai virus. In contrast, under parenteral anesthesia (i.e., intraperitoneal ketamine), mice which received cholera toxin and Sendai virus via the respiratory tract showed significantly higher anti-viral IgA and IgG antibody titers in nasal washes and IgG antibody in bronchoalveolar washes than mice which received the virus only.

We have shown that in mice cholera toxin can be an effective adjuvant for gastrointestinal immune responses against a virus. The adjuvant properties can be increased and even dissociated from the toxic properties if virus and toxoid are covalently linked. Finally, oral immunization with these preparations of cholera toxin/toxoid and Sendai virus can be used to prime for respiratory immune responses to Sendai virus in which protection from infection correlates with IgA in the upper and with IgG in the lower respiratory tract.

Based on the concept of a common mucosal immune system wherein mucosal associated lymphocytes traffic among the various mucous membranes, the murine gastrointestinal tract was immunized with Sendai virus antigens in order to elicit a virus-specific immune response in the respiratory tract. Multiple intragastric (oral) administration of live or killed Sendai virus induced IgA and IgG antiviral antibodies in both gastrointestinal secretions and serum. When cholera toxin as an adjuvant was included along with virus, gut IgA and IgG as well as serum IgA responses were enhanced. Antiviral antibodies induced in respiratory secretions by oral killed virus plus cholera toxin, however, were variable and protection from virus challenge was not demonstrated. Significantly higher levels of respiratory antiviral antibodies were induced if immunization with oral killed Sendai virus/cholera toxin was combined with intranasal administration of small amounts of killed virus. The combined immunization also resulted in protection of both the upper and lower respiratory tracts from virus infection. Protection of the upper respiratory tract was correlated with the presence of IgA antiviral antibodies in nasal washings. On the other hand, protection of the lower respiratory tract was correlated with IgG antiviral antibodies in bronchoalveolar lavage fluids. Immunization with intranasal killed virus alone conferred partial protection to the lower respiratory tract and no protection to the upper respiratory tract. Thus, oral immunization with killed virus antigen could prime for a protective immune response in the murine respiratory tract and this protective response included IgA antibodies.

Cholera toxin (CT), either mixed with or conjugated to unrelated protein Ag, is known to enhance the intestinal IgA response of rodents toward the unrelated Ag. Although relatively low doses of CT exert this gut mucosal adjuvant effect, the inherent toxicity of CT is a hindrance to its use in humans. Our report demonstrates that CT treated with 20 mM glutaraldehyde retains adjuvant properties but exhibits more than 1000-fold lower toxicity than untreated toxin. Glutaraldehyde was also used in a one-stage conjugation procedure to couple CT covalently to Sendai virus. Again, toxicity was reduced more than 1000-fold. This drop in toxicity is consistent with an observed 100-fold loss in binding capacity of the CT B subunit and a 20- to 50-fold reduction in adenylate cyclase activation by the CT A subunit. Oral administration of this virus-toxoid conjugate resulted in increased gut antiviral IgA titers compared with oral administration of either virus alone or of virus mixed with glutaraldehyde-treated toxin. This marked decrease in toxicity may afford a practical approach for the use of CT as a mucosal adjuvant.

Successful oral immunization to prevent infectious diseases in the gastrointestinal tract as well as distant mucosal tissues may depend on the effectiveness of an Ag to induce gut immune responses. We and others have previously reported that cholera toxin possesses strong adjuvant effects on the gut immune response to co-administered Ag. To explore further adjuvant effects of cholera toxin, the holotoxin or its B subunit was chemically cross-linked to Sendai virus. The resulting conjugates, which were not infectious, were evaluated for their capacity to induce gut immune responses against Sendai virus after oral administration to mice. Conjugating cholera toxin to virus significantly enhanced the adjuvant activity of cholera toxin compared to simple mixing. Cholera toxin B subunit, however, did not show an adjuvant effect either by itself or conjugated with the virus. Oral administration of the Sendai virus-cholera toxin conjugate was also able to prime for protective anti-viral responses in the respiratory tract. Mice that were orally immunized with the conjugate and intra-nasally boosted with inactivated virus alone showed virus-specific IgA titers in nasal secretions that correlated with protection against direct nasal challenge with live Sendai virus. For comparison, s.c. immunization was also studied. Systemic immunization with the virus-cholera toxin conjugate induced virus-specific antibody responses in serum as well as in the respiratory tract but failed to protect the upper respiratory tract against virus challenge. Systemic immunization plus an intra-nasal boost did, however, confer a variable degree of protection to the upper respiratory tract, which correlated primarily with bronchoalveolar lavage (lung) antibody titers.

Both nonlabeled and radiolabeled IgA mAb with specificity toward Sendai virus, a respiratory pathogen, were used to investigate the transport of serum polymeric and monomeric IgA into murine upper and lower respiratory secretions as well as into the gut. After purification by affinity chromatography, IgA mAb were fractionated into monomers and polymers by gel filtration and radiolabeled with 125I. Mice were injected i.v. with either 125I-monomer and 131I-albumin or 125I-polymer and 161I-albumin. At various times after injection, serum and gut, nasal and bronchoalveolar lavage samples were collected. The TCA precipitable radioactivities were determined and the selective transport indices calculated. The results indicated selective transport of polymeric IgA but not monomeric IgA from serum into upper respiratory and intestinal secretions. The degree of TCA precipitability in nasal lavage and to a lesser extent gut secretions suggested significant degradation of the antibody during or after transport. To investigate further the integrity of the IgA in mucosal secretions, ELISA viral binding activity of nonradiolabeled IgA was determined for both IgA incubated with nasal secretions in vitro and polymeric IgA recovered by nasal lavage 4 h after i.v. injection. Although reconstitution experiments indicated no significant loss of antibody binding activity after incubation of antibody with lavage fluid in vitro, only negligible ELISA binding activity was detected in nasal washes after i.v. injection of antibody. The data overall suggest that although there is a quantitatively small, but selective transport of polymeric IgA into the upper respiratory tract, this transport results in minimal functional antibody activity. Implications of these and other findings for strategies of oral immunization in prophylaxis against respiratory infections are discussed.