Intelligent Design Optimization System for Additively Manufactured Flow Channels Based on Fluid-Structure Interaction

Based on expert system theory and fluid–structure interaction (FSI), this paper suggests an intelligent design optimization system to derive the optimal shape of both the fluid and solid domain of flow channels. A parametric modeling scheme of flow channels is developed by design for additive manufacturing (DfAM). By changing design parameters, a series of flow channel models can be obtained. According to the design characteristics, the system can intelligently allocate suitable computational models to compute the flow field of a specific model. The pressure-based normal stress is abstracted from the results and transmitted to the solid region by the fluid–structure (FS) interface to analyze the strength of the structure. The design space is obtained by investigating the simulation results with the metamodeling method, which is further applied for pursuing design objectives under constraints. Finally, the improved design is derived by gradient-based optimization. This system can improve the accuracy of the FSI simulation and the efficiency of the optimization process. The design optimization of a flow channel in a simplified hydraulic manifold is applied as the case study to validate the feasibility of the proposed system.

Cough aerosol in healthy participants: fundamental knowledge to optimize droplet-spread infectious respiratory disease management

BACKGROUND

The Influenza A H1N1 virus can be transmitted via direct, indirect, and airborne route to non-infected subjects when an infected patient coughs, which expels a number of different sized droplets to the surrounding environment as an aerosol. The objective of the current study was to characterize the human cough aerosol pattern with the aim of developing a standard human cough bioaerosol model for Influenza Pandemic control.

METHOD

45 healthy non-smokers participated in the open bench study by giving their best effort cough. A laser diffraction system was used to obtain accurate, time-dependent, quantitative measurements of the size and number of droplets expelled by the cough aerosol.

RESULTS

Voluntary coughs generated droplets ranging from 0.1 - 900 microns in size. Droplets of less than one-micron size represent 97% of the total number of measured droplets contained in the cough aerosol. Age, sex, weight, height and corporal mass have no statistically significant effect on the aerosol composition in terms of size and number of droplets.

CONCLUSIONS

We have developed a standard human cough aerosol model. We have quantitatively characterized the pattern, size, and number of droplets present in the most important mode of person-to-person transmission of IRD: the cough bioaerosol. Small size droplets (< 1 μm) predominated the total number of droplets expelled when coughing. The cough aerosol is the single source of direct, indirect and/or airborne transmission of respiratory infections like the Influenza A H1N1 virus.

STUDY DESIGN

Open bench, Observational, Cough, Aerosol study.

H2O at the Phoenix landing site

The Phoenix mission investigated patterned ground and weather in the northern arctic region of Mars for 5 months starting 25 May 2008 (solar longitude between 76.5 degrees and 148 degrees ). A shallow ice table was uncovered by the robotic arm in the center and edge of a nearby polygon at depths of 5 to 18 centimeters. In late summer, snowfall and frost blanketed the surface at night; H(2)O ice and vapor constantly interacted with the soil. The soil was alkaline (pH = 7.7) and contained CaCO(3), aqueous minerals, and salts up to several weight percent in the indurated surface soil. Their formation likely required the presence of water.

EstimatingIn VivoAirway Surface Liquid Concentration in Trials of Inhaled Antibiotics

Antibiotic drugs exhibit concentration dependence in their efficacy. Therefore, ensuring appropriate concentration of these drugs in the relevant body fluid is important for obtaining the desired therapeutic and physiological action. Until recently there had been no suitable method available to measure or estimate concentration of drugs in the human airways resulting from inhaled aerosols or to determine the amount of inhaled antibiotics required to ensure minimum inhibitory concentration of a drug in the airway surface liquid (ASL). In this paper a numerical method is used for estimating local concentration of inhaled pharmaceutical aerosols in different generations of the human tracheobronchial airways. The method utilizes a mathematical lung deposition model to estimate amounts of aerosols depositing in different lung generations, and a recent ASL model along with deposition results to assess the concentration of deposited drugs immediately following inhalation. Examples of concentration estimates for two case studies: one for the antibiotic tobramycin against Pseudomonas aeruginosa, and another for taurolidine against Burkholderia cepacia are presented. The aerosol characteristics, breathing pattern and properties of nebulized solutions were adopted from two recent clinical studies on efficacy of these drugs in cystic fibrosis (CF) patients and from other sources in the literature. While the clinically effective tobramycin showed a concentration higher than the required in vivo concentration, that for the ineffective taurolidine was found to be below the speculated required in vivo concentration. Results of this study thus show that the mathematical ASL model combined with the lung deposition model can be an effective tool for helping decide the optimum dosage of inhaled antibiotic drugs delivered during human clinical trials.

Surface tension effects on instability in viscoelastic respiratory fluids

This paper establishes the mathematical formalism for the modeling of the mucus layer in the human trachea as a viscoelastic multiphase fluid system with surface tension with a view toward study of instability properties of the air-mucus system aimed at improving the design of new bioaerosol suppressing medication. The effects of surface tension, previously only conjectured and very poorly understood, are clearly established with quantitative relationships. Several very important physiological conclusions are obtained supporting one method of potential treatment and prevention of disease transmission by alteration of the mucus layer properties over other potential methods.

Improving prediction of aerosol deposition in an idealized mouth using large-Eddy simulation

Monodisperse aerosol deposition in an idealized mouth geometry with a relatively small inlet diameter (D (in) = 3.0 mm) was studied numerically using a standard Large Eddy Simulation (LES). A steady inhalation flow rate of Q = 32.2 L/min was used. Thousands of particles (2.5, 3.7, and 5.0 microm in diameter and rho (f) = 912.0 kg/m(3) density) were released separately in the computational domain and aerosol deposition was determined. The total aerosol deposition results in this idealized mouth were in relatively good agreement when compared with measured data obtained in separate experiments, showing considerable improvement over the standard RANS/EIM (Reynolds Averaged Navier-Stokes/Eddy Interaction Model) approach.

Liquid Atomizing: Nebulizing and Other Methods of Producing Aerosols

Liquid atomization (or nebulization) is the most traditional method of drug delivery to the lung. Although other methods seem to often be preferred for the delivery of new drugs, nebulizers are experiencing a revival, with new devices based on different atomization techniques, and the more traditional jet nebulizers evolving to become "smart nebulizers." These smart devices synchronize delivery with the patient's breath, estimate or measure delivered dose, provide feedback and data storage, and in some cases control breathing maneuvers. Besides adding new features, new nebulizers are also addressing traditional shortcomings, namely, reducing size, bulkiness, and power consumption. But in the longer term, nebulizers are expected to offer even more important features. Following the trend toward individually optimized therapy, nebulizers will be able to estimate deposited dosage and concentrations in the lung. In addition, as progress in nanotechnology allows the development of smart drug carrying particles, advanced liquid nebulization is expected to be the delivery mode of choice for these smart particle aerosols.

Spray-freeze-dried liposomal ciprofloxacin powder for inhaled aerosol drug delivery

Spray-freeze drying was utilized to manufacture a liposomal powder formulation containing ciprofloxacin as a model active component. The powder forms liposomally encapsulated ciprofloxacin when wetted. Aerosol properties of this formulation were assessed using a new passive inhaler, in which the powder was entrained at a flow rate of 60l/min. A mass median aerodynamic diameter (MMAD) of 2.8 microm was achieved for this formulation. Using the experimental dispersion testing data, ciprofloxacin concentration in the airway surface liquid (ASL) was calculated using a Lagrangian deposition model. The reconstitution of the powder in various aqueous media gave drug encapsulation efficiencies as follows: 50% in water, 93.5% in isotonic saline, 80% in bovine mucin, 75% in porcine mucus and 73% in five-fold-diluted ex vivo human cystic fibrosis patient sputum.

Use of an impinging jet for dispersion of dry powder inhalation aerosols

The dispersion of Ventodisk (salbutamol sulphate with lactose) from different drug reservoirs by an air jet at normal impingement is examined experimentally. The effect on dispersion efficiency of jet velocity, nozzle location, reservoir size and shape, and the loaded dose is investigated for possible design of new dosing methods or inhalers. Results show that higher jet velocity (as high as feasible), lower drug loading (2 mg or smaller), a cylindrical hole reservoir (6 mm in diameter and 3 mm in depth) and a medium distance (approximately 5 jet diameters) from the nozzle to the reservoir yield optimum dispersion. The dispersed fine particle dose improves by a factor of 2-3 times between optimized conditions and poor conditions.

Albuterol aerosol delivered via metered-dose inhaler to intubated pediatric models of 3 ages, with 4 spacer designs

OBJECTIVE

To determine the amount of albuterol, in various particle size ranges, delivered from a hydrofluoroalkane-propelled metered-dose inhaler (Airomir) in 3 models of pediatric intubation (ages 8 months, 4 years, and 16 years) using 4 types of aerosol reservoir: 3 spacers (ACE, AeroChamber HC MV, metal NebuChamber without 1-way valve) and 1 holding chamber (metal NebuChamber with 1-way valve).

METHODS

Five reservoirs of each type were tested with albuterol sulfate delivered via metered-dose inhaler that delivers 100 microg of albuterol per actuation. Each reservoir was connected to an endotracheal tube (ETT) that corresponded to the given patient age (8 months = 4 French; 4 years = 5 French; 16 years = 7.5 French) and to a valved system that allowed connection of the ETT to a cascade impactor. Simulated tidal volumes representative of children of the given ages were passed through the reservoir. Both the cascade impactor and the ETT were enclosed within a 100% humidity, 37 degrees C environment.

RESULTS

For the total amount of albuterol inhaled onto the impactor, and both the 1.1-4.7 microm and 1.1-3.3 microm inhaled fine-particle fractions, the NebuChamber-with-valve showed significantly greater drug delivery than the NebuChamber-without-valve, the AeroChamber HC MV, or the ACE (p < 0.001). Among the reservoirs without valves the NebuChamber showed significantly greater delivery than the AeroChamber HC MV or ACE (p < 0.001) for total drug deposition and for both the 1.1-4.7 microm and 1.1-3.3 microm fine-particle fractions. These results were consistent over all age groups. The AeroChamber HC MV had significantly greater delivery (total deposition) than the ACE (p < 0.001), except in the 4-year-old model. There were no significant differences between the AeroChamber HC MV and the ACE for either the 1.1-4.7 microm or the 1.1-3.3 microm fine-particle fraction.

CONCLUSION

An aerosol reservoir with 1-way valve positioned between the spacer and the ETT improved the amount of inhaled albuterol 300-900%, compared to the other reservoirs.

The Effect of Breathing Pattern on Nebulizer Drug Delivery

The significance of using breathing patterns with simplified functional shapes in vented jet nebulizer research is examined. This study is comprised of three parts: (1) The measurement and analysis of human breathing patterns, (2) the subsequent in vitro testing of the effects of breathing pattern differences using a consistent bench test method, and (3) a computer modeling of these effects on the estimated regional drug deposition in the human lung. Breathing through a Pari LC-Star nebulizer caused statistically significant changes (p < or = 0.05) in measured human breathing patterns when compared to normal breathing. Observed changes included an increase in the tidal volume (34%) and period (39%). Additionally, the average duty cycle shifted 12% towards a more symmetrical breath due to the unequal increase in the inhalation and exhalation times (55% and 28%, respectively). The position of the point of maximum flow in each breath phase shifted towards the beginning and end of the breath for the inhale and exhale by 28% and 48%, respectively. The bench testing revealed that breathing pattern shape variation caused statistically significant differences in nebulizer output only in two cases. Decreasing duty cycles and shifting the point of maximum flow towards the beginning of the breath both result in a decrease in output efficiency. Square flow patterns produced slight but consistently higher output efficiencies (average 2.1% higher) and a constant output particle size over the course of each breath, different from the other non-square patterns. Numerical simulations revealed no significant dosage differences resulting from breathing pattern shape variations. However, square wave patterns consistently produced slight overpredictions in comparison with real nebulizer patterns. In contrast, sine wave patterns were found to produce essentially the same results as nebulizer patterns in both the bench tests and in the deposition simulations. This suggests that sine wave shapes are preferable for simulating breathing when bench testing drug delivery using vented jet nebulizers.

In vitro effect of a holding chamber on the mouth-throat deposition of QVAR (hydrofluoroalkane-beclomethasone dipropionate)

Experimental work has been conducted on the effect of an add-on holding chamber (Aerochamber) on the characteristics of deposition in a mouth-throat model using 100-microg hydrofluoroalkane-beclomethazone dipropionate (QVAR) metered dose inhalers at inhalation flow rates of 28.3, 60, and 90 L/min. A filter or cascade impactor downstream of the mouth-throat collected aerosol not depositing. The results emphasize the important well documented effect of a valved holding chamber (VHC), in reducing drug deposition in the mouth-throat. This reduction is largest (24% of nominal dose) at the lowest flow rate tested, becoming insignificant at 60 L/min. Total amount of drug delivered distal to the mouth-throat increases with flow rate both with and without a holding chamber, increasing from 42% to 69% of the nominal dose without a VHC as the inspiratory flow rate increases from 28.3 to 90 L/min. The effect of the holding chamber on post mouth-throat delivery was small, reaching significance only at the highest flow rate (90 L/min), where an increase by 8% of the nominal dose was observed. No significant effect on MMAD of beclomethasone-dipropionate occurred when the holding chamber was used. An argument based on the interaction between induced turbulence and particle inertia is used to shed light on the above observations.

In vitro aerosol delivery and regional airway surface liquid concentration of a liposomal cationic peptide

A liposome encapsulation was optimized for the entrapment and aerosol delivery of an alpha-helical cationic peptide, CM3, which had shown good antimicrobial and antiendotoxin activity in vitro. The encapsulation procedure and the phospholipids used were selected to maximize both the encapsulation and nebulization efficiencies, without compromising liposomal integrity during nebulization. The best compromise was found with dimyristoyl phosphatidylcholine and dimyristoyl phosphatidylglycerol (3:1 molar ratio), which allowed for peptide encapsulation levels of 730 microg/mL using 30 mM lipid concentration. The aerosol produced with the selected liposomal formulation was subsequently analyzed for determination of size distribution and nebulizer efficiencies. These quantities were used as input for a mathematical lung deposition model, which predicted local lung depositions of the liposomal peptides for three models of lung geometry and breathing patterns: an adult, an 8-year-old child, and a 4-year-old child. The deposition results were then applied to a novel model of airway surface liquid in the lung to assess the concentration of the deposited peptide. The resulting concentration estimates indicate that the minimum inhibitory levels of CM3 can be reached over most part of the tracheobronchial region in the adult model, and can be exceeded throughout the same region in both pediatric model subjects, using a valved jet nebulizer with a 2.5mL volume fill.

Validating deposition models in disease: what is needed?

To develop theoretical deposition models, assumptions are introduced to make the models computationally affordable. For this reason, experimental (in vivo) validation of such models is needed to give confidence to the assumptions being made. However, for an in vivo deposition experiment to be considered useful for validation of a model, a number of parameters must be measured in the experiment for input to the model. Ideally, these parameters would include time-dependent breathing flow rates during aerosol exposure, properties of the inhaled aerosol as a function of time during the breath (including particle size distribution, aerosol mass fraction, as well as hygroscopic properties, inhaled temperature and humidity if hygroscopicity is important), in addition to anatomical regional deposition data and detailed lung geometry measurements. Furthermore, because of the dependence of extrathoracic filtering on the inlet conditions at the mouth and the complexity of modeling deposition in this region, experimental data on the filtering properties of the mouth-throat are needed. Although some of the above parameters are impractical to measure with current experimental techniques, it would greatly aid the development of deposition models if as many of these parameters as possible were measured in future in vivo deposition experiments. Data exemplifying the importance of measuring the above parameters is discussed.

Overcoming the adverse effect of humidity in aerosol delivery via pressurized metered-dose inhalers during mechanical ventilation

The well-known problem of reduced drug delivery that occurs when heated, humid air is used with pressurized metered-dose inhalers (pMDIs) and spacers in intubated settings is carefully studied with Airomir using an in vitro model under controlled conditions of temperature and humidity. A better understanding of the physical processes leading to the aforementioned drop in performance is obtained, and a method is devised to circumvent the problem without having to reduce the temperature or humidity of the ventilator circuit. The present study shows that the mole fraction of water vapor in the ventilation air (and not the temperature) is the major factor behind the sharp drop in the amount of drug delivered to the lung. However, the presence of water vapor does not affect performance because of hygroscopic growth. Instead, it influences the initial atomization process and the early stages of aerosol generation. Removal of these negative effects can be achieved by using a larger spacer that allows longer times for the aerosol to evaporate, as is demonstrated in the present study.

Lung delivery of aerosolized dextran

The ability of nebulizers to deliver dextran (nominal molecular mass, 4,000 g/mol) to the lung as an inhaled aerosol is evaluated by in vitro experimental methods and mathematical models. Dextran in isotonic saline was aerosolized by four nebulizer types (Pari LC STAR, Hudson T-Updraft II, Acorn II, and Sonix 2000) at dextran concentrations </= 400 mg/ml and with 2.5- and 4-ml volume fills. Aerosols inhaled during breath simulation were characterized by in-line phase Doppler anemometry, filter collection, osmometry, and gravimetry. Mathematical models were used to estimate amounts of the characterized aerosols depositing in the different regions of lung models, and mathematical models of mucous thickness were then developed to estimate initial concentrations of the depositing dextran in the mucus of each conducting airway generation. Models of three subjects (4 yr old, 8 yr old, and adult) were used. The high viscosity of the dextran solutions tested (up to seven times that of water) negatively impacts nebulization, and results in poor performance with most delivery systems tested. Our results suggest that airway mucosal dextran concentrations associated with efficacy in previous animal and in vitro models are achievable with reasonable delivery times (</= 12 min) with only one of the delivery systems/formulations tested: the Pari LC STAR nebulizer, using a 2. 5-ml volume fill and a dextran concentration of 200 mg/ml.

Epitope mapping of homologous and cross-reactive antigens by monoclonal antibodies to streptococcal cell membrane (mAb to SCM)

An approach to epitope mapping of a series of anti-streptococcal cell membrane (SCM) mAbs is described. Evaluations by enzyme-linked immunosorbent assay (ELISA) of one control mAb HB-35 and 13 different anti-SCM mAbs were made on homologous SCM antigen and human basement membrane antigens isolated from glomeruli (GBM) and lung (LBM). These anti-SCM mAbs were previously shown to be cross-reactive in a variety of systems with both GBM and LBM. The binding capacities were measured for all 14 mAbs on ELISA plates sensitized with SCM antigen or the cross-reactive GBM or LBM antigens, at 5 micrograms/ml or approximately 20 pM/well. From the 50% binding capacity dilution the pM of mAb bound/pM antigen-well was calculated which translated into an estimate of the ratio-number of epitopes bound. Observations with the homologous and cross-reactive antigens showed multiple reactive epitope ratios to eight mAbs whereas the other five yielded a ratio value of one or two on the tested antigens. Plates blocked with a specific dilution of one mAb evaluated the binding by a second mAb providing both binding and specificity data. One mAb (I-F-3) blocked all the other anti-SCM mAbs on all three antigen plates. An additive effect was noted by three mAbs, I-G-8, II-C-4 and II-D-8 with most of the other mAbs. The order of placement, however, made distinctive differences; II-F-4 showed an additive or enhancement effect on I-B-5 but no reciprocal effect was seen. A similar effect was made with I-G-8 and II-C-4 or I-F-7. Possible interpretations are that each mAb is binding different epitopes each fully exposed, and the order of placement of the mAbs makes no difference. Where an enhanced effect was observed it is suggested that the binding of the first mAb changed the conformation of the antigen, thereby opening and exposing additional epitope(s) to the second antibody. Or, in contrast, where the second mAb was blocked by the first, a fixing of the protein conformation is suggested thereby occluding the other epitope, as seen with I-F-3 and II-C-4. These epitope mapping procedures confirmed that all 13 anti-SCM mAbs were binding at different epitopes. The nature of basement membrane collagens and how this relates to post-streptococcal sequelae will be discussed.

Immunochemical studies of streptococcal cell membrane antigens immunologically related to glomerular basement membrane

Pursuing an autoimmune model for the etiology of poststreptococcal glomerulonephritis, protein antigens isolated from the cytoplasmic membrane of nephritogenic group A Type 12 Streptococcus pyogenes were immunochemically characterized using antistreptococcal cell membrane (SCM) monoclonal antibody (MAb) cross-reactive with glomerular basement membrane (GBM). Low molecular weight (9.2, 7.0, 4.7, 2.3 kDa) HPLC-purified SCM polypeptide antigens were characterized by competitive inhibition and equilibrium dialysis. Competitive inhibition of the MAb, by different sized SCM polypeptide antigens showed an inverse relationship between the size of these antigens and the molar amount required to obtain 50% inhibition of the MAb, confirming previous observations that suggested that these SCM antigens exhibit increasing epitope concentration with increasing size, that is constant epitope density. The observed changes in epitope concentration correlated with differences in the valence and affinity of the MAb as determined by equilibrium dialysis. The Kds of the MAb for 9.2-, 7.0-, 4.7-, and 2.3-kDa SCM antigens ranged from 7.42 x 10(-7) to 1.15 x 10(-5). The experimentally determined MAb valence for these antigens was 2 for the 9.2-kDa antigen and approached 10 for the smaller antigens. Finally, the similarity of these SCM antigens was reflected in similar amino acid compositions; of note, these data agreed with the compositions previously reported for sized GBM antigens. Concentrations of Asp, Thr, Ser, Glu, Gly, Ala, Val, Ile, and Leu paralleled increasing epitope concentration. Apparent N-terminal blocking prevented sequencing of these peptides, but these immunochemical data suggest that intact SCM antigen recognized by the anti-SCM MAb consists of repeating epitopes, an observation consistent with the cytoplasmic membrane source of the antigen.

Tracking the in vivo localization of streptococcal cell membrane (SCM) monoclonal antibodies: potential model for post-streptococcal sequelae

Placement of ten different anti-streptococcal monoclonal antibody (mAb) secreting hybridoma cells, as well as positive and negative controls into animals and sacrificing on a daily basis showed a difference in the tissue sites of accumulating mAb as noted by fluorescent antibody testing. Initial binding of the mAb was noted by day two on the kidney GBM in all the animals. Striated muscle tissues tested positive starting at day nine with only four of the mAbs, by which time the GBM was strongly positive. Fluorescent antibody testing of heart and skeletal muscle from animals in which one of the polyreactive IgM mAb secreting hybridoma cell lines was placed showed a distinctive staining of the Z-lines. Indirect fluorescent and immunoperoxidase testing as well as competitive blocking experiments confirmed the reactivity of this mAb for the Z-line of heart and skeletal muscle. Immunodots and Western blots along with direct and blocking assays confirmed that the critical cross-reactive Z-line antigen was alpha-actinin, supporting the concept that this anti-SCM mAb was reactive both in vivo and in vitro. These results confirm the cross-reactive nature of anti-SCM antibodies for mammalian tissue and bear important implications on the etiology of post-streptococcal glomerulonephritis and rheumatic heart disease.

Localization of [14C] labeled anti-streptococcal cell membrane monoclonal antibodies (anti-SCM mAb) in mice

Six different hybridomas secreting anti-SCM mAb and one control mAb were placed into adult mice along with [14C] amino acids for biosynthetically labeling. After sacrifice, the 14C mAb ascites along with serum, heart, kidney, lung and skeletal muscle were recovered. Tissue associated specific radio-activity (SpAc) and microscopic structural analyses were performed. Confirmation of mAb specificity was by both immunodot blots as well as Western blot analysis. Peritoneal injection of measured doses of anti-SCM mAb yielded tissue SpAc confirming their in vitro specificities. Two of the mAb showed strong reactivity to both renal (GBM) and lung basement membrane (LBM), two were mainly GBM reactive and two showed polyreactivity with a marked reactivity to a Z-line antigen. Autoradiographic light microscopy confirmed that the anti-SCM mAbs bound to both GBM and LBM and to Z-line antigen. Titrated doses of the mAb yielded autoradiographic confirmation in which the grain number on the GBM and LBM increased with increasing dose of mAb for all mAb except the control. This effect was not seen in the muscle tissues but anatomical localization at the Z-line was consistent. The major significance of these studies is the demonstration that circulating antibodies to SCM can react in vivo with normal mammalian antigens adding confirmation to the in vitro specificity of these cross-reactive anti-SCM mAbs.

Experimental autoimmune pinealitis in the rat: ultrastructure and quantitative immunocytochemical characterization of mononuclear infiltrate and MHC class II expression

Lewis rats immunized with Peptide M (an oligopeptide epitope of the S-antigen protein) developed experimental autoimmune uveoretinitis (EAU) and experimental autoimmune pinealitis (EAP). Temporal changes in mononuclear infiltrate to the pineal gland were quantitated by computer image analysis of sections immunostained with monoclonal antibodies to specific mononuclear populations. T helper/inducer cells (W3/25+) and monocyte/macrophages (OX-42+) were elevated during the early phases of inflammation (day 15) while cytotoxic/suppressor T cells (OX-8+) were elevated at days 15 and 21. Expression of MHC class II (OX-6) was markedly enhanced on pineal glia, but was not present on vascular endothelia during EAP. Ultrastructurally, many capillaries exhibited thickenings of the endothelia and basal lamina. EAP had little effect on the fine structure of pinealocytes and glia and there was little evidence of cellular destruction by day 21, in contrast to the extensive retinal destruction resulting from EAU. These findings suggest fundamental differences between EAU and EAP related to mechanisms of antigen processing/recognition in autoimmune diseases. Our study further indicates the importance of EAP as a model to investigate neuroendocrine-immune interactions.

Hybridomas to specific streptococcal antigen induce tissue pathology in vivo; autoimmune mechanisms for post-streptococcal sequelae

A gross examination of organs from approximately 100 mice which were producing ascites fluids toward a series of streptococcal reactive monoclonal hybridomas showed, in some animals, what appeared to be autoimmune-like findings. A pattern of major lung pathology was associated with specific clones. These specific hybridomas led to the development of an experimental autoimmune animal model mimicking a Goodpasture's syndrome. Tissue injury was induced in mice, on a dose dependent basis, by the injection of monoclonal antibody generated against streptococcal cell membrane (SCM) antigens. A more severe onset of the pathology, also on a dose dependent bases, was induced by placement of the anti-SCM mAb secreting hybridoma cells into the peritoneal cavity of the host. Severity of observed lesions was dependent upon the number of cells injected (10(5), 5 x 10(5), 10(6) or 10(7], as well as the animals' sex. Severe and total hemorrhagic lungs were seen in animals challenged with 1 x 10(6) hybridomas cells when sacrificed on the tenth day. In all cases the lesions were greater in the female litter mate than the male. Gross and histologic observations were confirmed by lung/body weight ratios. Pulmonary hemorrhage ranged from slight, when mAb was injected at a low dose of 24 micrograms/g, to severe when 96 micrograms/g was injected. Reported findings were based on the review of approximately 300 mice. Immunochemical evaluations and ELISAs confirmed the ability of these anti-SCM mAb to react with glomerular basement membrane (GBM) antigens as well as lung basement membrane (LBM). Mitogenic experiments indicated that the parent immunogen (SCM) used to generate immunocytes was non-stimulatory to lymphocytes.

Isolation and partial characterization of antigens from basement membranes and streptococcal cell membrane (SCM) employing anti-SCM monoclonal antibody

Monoclonal antibodies (mAb) against streptococcal cell membrane (SCM) antigen were used to identify specific cross-reactive peptides prepared by trypsin digestion of purified glomerular basement membrane (GBM) and lung basement membrane (LBM). Anti-SCM mAb-coupled HPLC columns were used to affinity isolate soluble LBM, GBM, and SCM antigens which then were sized by HPLC. Alternatively, SCM, GBM, and LBM digests were subjected to an initial separation by HPLC into component polypeptides, followed by affinity purification and ELISA of these fractions using anti-SCM mAb. Comparison of the antigenic reactivities by ELISA of the sized polypeptides on a nanomolar basis permitted the estimation of their individual relative epitope densities. The results for SCM antigens showed increasing epitope density with increasing molecular size, which suggests that intact SCM consists of repeating epitopes. Low mol. wt GBM polypeptides in nanogram amounts inhibited mAb binding to SCM, indicating that these small GBM polypeptides may similarly contain more than a single cross-reactive epitope. The identification of these cross-reactive epitopes in LBM and GBM has important implications for the etiology of post-streptococcal sequelae.

The isolation of cross-reactive monoclonal antibodies: hybridomas to streptococcal antigens cross-reactive with mammalian basement membrane

Based upon the assumption that post-streptococcal sequelae are the result of cross-reactive antibodies, hybridomas were prepared from the spleens of mice immunized with Group A type 12 streptococcal cell membranes (SCM) specifically to screen for such cross-reactive antibodies. One fusion produced a cell population displaying antibodies reactive to both SCM and glomerular basement membrane (GBM) antigens as demonstrated by ELISA technique. Ascites produced by this cell population also showed reactivity to lung basement membrane (LBM). Limiting dilution procedures have produced 15 monoclonal hybrids with both anti-SCM and anti-GBM activity. Confirmation of the cross-reactive and monoclonal nature of the antibody was accomplished by both direct and indirect competitive ELISA. These observations have established that unique cross-reactive antibody-secreting hybrid cells with reactivity to both SCM and basement membrane (BM) antigens can be isolated by standard cloning procedures.

Age effects on the reactivity of antistreptococcal cell membrane antisera to murine glomerular basement membrane. In vitro versus in vivo analysis

Antisera to the streptococcal cell membrane (SCM) were evaluated for their reactivity to murine glomerular basement membrane (GBM) in four strains of mice. Animals were studied on a daily basis from birth through 3 months and weekly thereafter through 18 months. Paired animals were compared for in vivo binding of antibody versus an indirect fluorescent antibody technique on fresh kidney sections. The findings demonstrated a granular type GBM staining for all anti-SCM which were positive. Nonspecific background staining accompanied most of the indirect fluorescent antibody sections tested while being totally absent for the direct fluorescent test on tissue from in vivo challenge of the primary antibody. The in vitro testing showed tissue from young mice (0-6 days old) to be most reactive, while the strongest reactivity was seen in the age group of 10-20 days for in vivo testing. These cross-reactive antibodies, i.e., GBM-binding anti-SCM, are best evaluated by in vivo methods where tissue is taken 4 days after antiserum injection. Animals of the age range 6-8 weeks were often negative, indicating that this age range selected for many studies may not be the most favorable one via either in vitro or in vivo studies.

Transfer factor and repeated otitis media

The effect of transfer factor (TF) was investigated in 12 children with repeated otitis media. These patients were immunologically compared to a control group of 23 age-matched healthy children. Levels of immunoglobulins, total and "active" T-cells, and phagocytic activity of granulocytes and monocytes were evaluated in the 12 children prior to, during, and after TF therapy. Percentages of "active" T cells and absolute numbers of "active" T and total T cells, which were initially low in the patient group, increased significantly after TF therapy to statistically match those of the healthy control group. The percentage of phagocytic monocytes in patients after therapy did not differ from healthy children; however, the percentage of phagocytic granulocytes remained depressed significantly. The levels of IgG, IgA, and IgM were unaffected by the therapy although the IgA and IgM were higher in the patient population throughout the study. After therapy, one-half of the patient population remained asymptomatic for a 1-year period and the others had markedly reduced attack rates.

"Nonfibrillar" chitin associated with walls and septa of Trichophyton mentagrophytes arthrospores

Two morphologically distinct forms of chitin were found in the arthrospore walls and septa of Trichophyton mentagrophytes. Two-thirds of the total wall chitin was the microfibrillar and chitinase-sensitive form. The remaining chitin existed in a previously uncharacterized "nonfibrillar" form and was insensitive to the action of Streptomyces chitinase. Exhaustive digestion of the arthrospore walls and septa with beta (1 leads to 3)-glucanase and chitinase followed by extraction with NaOH (1 N, 100 degrees C, 3 h) resulted in a fraction which retained the original wall shape. This fraction consisted of 85% N-acetylglucosamine, 2.0% galactosamine, 2.5% glucose, and 0.4% amino acids, 74% of which were lysine. Both its infrared spectrum and its X-ray diffraction pattern were almost identical to those of authentic chitin. There was no evidence of the presence of muramic acid, hexuronic acid, phosphate, or sulfate in this fraction. Its resistance to chitinase was due neither to the presence of protective wall layers or melanin nor to its close or covalent association with beta-glucan. Aside from its nonfibrillarity, this hexosamine polymer differed from authentic chitin in that it was soluble in 6 N HCl and 7.5 N NaOH. The development of this nonfibrillar chitin layer in the cell wall during arthrosporogenesis of T. mentagrophytes may be related to the arthrospores being resistant to a variety of antifungal agents.

Antistreptococcal cell membrane antisera and the antigenicity of glomerular basement membrane

Antigenic cross-reactivity between mouse or human glomerular basement membrane (GBM) and group A type 12 beta-hemolytic streptococcal cell membranes (SCM) was evaluated by immunofluorescent techniques. Neonatal tissue proved to be more reactive than adult tissue with anti-SCM and anti-GBM antisera whose specificity was toward protein epitopes. Removal of carbohydrate moieties by enzymes (CHOase), converted adult tissue antigenicity to that of the neonate. Partial removal of some CHO, especially sialic acid, gave a partial enhancement of antigenicity. Contrariwise, antisera directed toward CHO epitopes while showing some reactivity in adult tissue gave variable results in the neonatal or young tissue. Anti-CHO sera of SCM were negative while anti-CHO sera of GBM immunogens did react slightly. None of the antisera used in these studies gave positive reactivity to heart, lung or liver tissue from any mice.

The role of glycoprotein carbohydrate in the immunological reactivity of antistreptococcal cell-membrane and antiglomerular basement-membrane antisera

Rabbit antisera to "carbohydrate-rich" antigens prepared from group-A, type-12 streptococcal cell-membrane and human glomerular basement-membrane were found to react by an indirect fluorescent-antibody test with the glomerular basement membrane of adult human kidney. This activity was absent or diminished in neonatal tissue. Removal of the carbohydrate epitopes from the adult tissue by means of carbohydrases removed the immunological activity. Antisera against the "carbohydrate-rich" antigens showed immunological reactivities distinctly different from those against the parent native immunogens--streptococcal cell membrane or glomerular basement membrane--which proved to be directed towards the portein epitopes.

Glomerular basement membrane: its antigenicity evaluated by antistreptococcal cell membrane antisera

Rabbit antistreptococcal membrane antisera have been demonstrated to cross-react with both human and mouse glomerular basement membrane (GBM). Though some antisera may display broad antimammalian tissue, specificity select sera were found that were specific for the GBM. The antigenicity of the GBM was also shown to change with age where certain antisera reacted with adult tissue but not with young and vice versa. Two key periods were demonstrated, one starting at about 10 days and another at about 3 months. One in vitro, indirect fluorescent antibody testing the young tissue (10-20 days) was often more reactive than older tissue. By in vivo testing these same antisera showed greater activity in animals older than 3 months. These results establish that these antisera may serve as a vital adjunct to all antisera for recognition of specific GBM antigens.

Behcet syndrome: with immunologic evaluation

A case of Behcet syndrome with immunologic evaluation, including screening of a vulvar ulcer for IgG, IgM, IgA, and fibrinogen by direct fluorescent microscopy is presented. Attempts were made to demonstrate cellular and humoral immune responses to mucosal antigens by lymphoblast transformation in the presence of cadaver esophageal mucosal extracts and indirect immunofluorescence using autologous serum and mucosal tissue. Serial measurements of percentages of total T, active T, and B lymphocyte populations, and lymphocyte response to phytohemagglutinin (PHA) stimulation during the course of Behcet syndrome are also presented. Clinical evaluation, histology of a Behcet vulvar ulcer, and a 2-year followup with good response to chlorambucil are reviewed.

T and B cells in pregnancy

The present study reports on the relative percents and absolute numbers of peripheral blood total T, active T, and B lymphocytes in pregnant women throughout gestation. These data agree with other studies reporting normal T and B cell populations during pregnancy.

Characterization of group A streptococcal M-proteins purified by two methods

Ten different group A streptococcal M-protein preparations purified by trichloroacetic acid precipitation and three M-protein preparations purified by cellulose chromatography were examined by SDS and polyacrylamide gel electrophoresis, and analyzed for amino acid composition and N-terminal amino acids. Fingerprinting (both tryptic and chymotryptic) was performed on the cellulose purified preparations of M1, M12, and M29 proteins which showed these proteins to be structurally related. Trypsin produced mas with 37 to 42 peptides, whereas chymotrypsin digestion resulted in 8 to 12 peptides, depending on the M-type. Sequencing was performed on the M12 protein and tentative identification of nine N-terminal amino acids made. Molecular weights of the cellulose and TCA-purified M-proteins were determined by SDS gel electrophoresis and chromatography on G-200 Sephadex, with comparable results, indicating followed the patterns established for M-proteins, with high concentrations of lysine, aspartic acid, glutamic acid, alanine, and leucine. All 10 proteins had L-alanine as their N-terminal amino acid. Evidence for a one way cross-reaction between type 1 and type 29 streptococci was also found.

Immunologic cross-reactivity between antisera to group A, type 12 streptococcal cell membrane and human glomerular basement membrane. The effect of age and carbohydrate content

Antisera to group A, type 12 streptococcal cell membrane and human glomerular basement membrane was evaluated, by indirect immunofluorescence, on adult and neonatal human kidney sections, before and after carbohydrase treatment. Cleavage of GBM carbohydrate potentiated the reactivity of SCM antisera on adult GBM, but not neonatal GBM which in general showed maximal activity without CHOase treatment. Of 22 sera checked 17 showed positive reactivity versus human GBM. Chemical analyses showed that adult GBM contained more carbohydrate than did neonatal GBM, which may explain the observed masking effect.

Increased immunologic reactivity between human glomerular basement membrane and group A type 12 streptococcal cell membrane after carbohydrase treatment

Anti-streptococcal cell membrane and anti-human glomerular antisera were evaluated on normal human kidney sections by an indirect immunofluorescent test both before and after absorptions with homologous and heterologous membrane preparations. The observed cross-reactions were potentiated by removal of carbohydrate units from both membrane-types by carbohydrase, a mixture of carbohydrate-cleaving enzymes.

Simplified method for the purification of group A streptococcal M-proteins: solution of the multiple banding problem

A simple and rapid procedure for the isolation in high yield (about a 30% recovery based on the total 30 to 60% ammonium sulfate recovery) of homogeneous purified group A streptococcal M-protein is described. M-proteins extracted from whole cells of group A streptococci by treatment with hot HCl were neutralized, fractionated with ammonium sulfate, dialyzed, lyophilized, and then subjected to treatment with hot 60% trichloroacetic acid. This was shown to produce an M-protein preparation, free of group A carbohydrate activity and extraneous antigens, in yields up to 10-fold higher than previous methods in about one-fifth the time. These M-protein preparations were shown to: (i) have similar amino acid compositions to their respective type-specific proteins purified by diethylaminoethyl and O-(carboxymethyl) cellulose chromatography, (ii) react with their respective type-specific antisera in Ouchterlony diffusion, (iii) produce antisera in rabbits capable of promoting streptococcal long-chain formation in vitro, and (iv) give only one major band on polyacrylamide gel disk electrophoresis. The data allow for an explanation of the hitherto described multiple banding M-proteins seen on acrylamide electrophoresis.