Bacterial peptidoglycan induces in vitro rheumatoid factor production by lymphocytes of healthy subjects

The present studies were carried out to further characterize the polyclonal B cell activating properties of bacterial peptidoglycan (PG) and to determine if this ubiquitous agent induces in vitro IgM rheumatoid factor (RF) production by lymphocytes from healthy volunteers. Peripheral blood mononuclear cells (PBMC) were cultured in the presence of peptidoglycan, pokeweed mitogen (PWM), a standard polyclonal B cell activator, or additional culture medium. Supernatants were harvested on days 7-8 for determination of total IgM, total IgG, and IgM RF by an enzyme-linked immunosorbent assay (ELISA). PG and PWM induced comparable amounts of total IgM production but PG was a less potent stimulant of total IgG production. PG induced in vitro IgM-RF production in 9/33 experiments, a frequency of response of less than that observed in corresponding PWM stimulated cultures (22/33 experiments). PG-induced IgM-RF production depended upon active protein synthesis and did not correlate with the magnitude of PG-induced total IgM production. The latter finding suggests that PG-induced IgM-RF may not merely reflect polyclonal B cell activation. These results add to a growing list of PG's functional properties and provide further impetus for considering this ubiquitous agent as a potential stimulant for in vivo RF production.

Bioadhesive polymers as platforms for oral controlled drug delivery II: synthesis and evaluation of some swelling, water-insoluble bioadhesive polymers

A series of cross-linked, swellable polymers was sythesized from monomers such as acrylic acid, methacrylic acid, and others with various cross-linking agents to produce a range of polymers differing in charge densities and hydrophobicity. The densities, rate, and extent of hydration of the polymers were determined. An increase in the number of hydrophobic groups in the polymer structure reduced hydration whereas the density of the polymer was unaffected. A sensitive in vitro method for measuring adhesion of polymer to tissue from the rabbit stomach was developed. Polymers of acrylic acid loosely cross-linked (0.3%, w/w) with three different agents, divinyl glycol, 2,5-dimethyl-1,5-hexadiene, and divinylbenzene, showed the same degree of bioadhesion while poly(methacrylic acid-divinylbenzene) showed reduced bioadhesion. The small percent of cross-linking agent, irrespective of physicochemical properties, did not contribute substantially to bioadhesion, whereas the starting monomer had a large effect. The effect of pH on the bioadhesion of poly(acrylic acid-divinyl glycol) was studied at constant temperature, ionic strength, and osmolality. The polymer showed maximum adhesion at pH 5 and 6 and a minimum at pH 7. Gastrointestinal transit studies of cross-linked polymers in rats were studied. Poly(acrylic acid-divinyl glycol) and poly(methacrylic acid-divinylbenzene) were shown to have substantially longer GI transit times than the control, Amberlite 200 resin beads. The delay in transit time was due to bioadhesion of the polymer to the mucin-epithelial cell surface which was clearly observable on animal autopsy. The acrylic acid polymer showed a longer GI transit time than the methacrylic acid polymer, and this in vivo GI transit result is consistent with in vitro bioadhesion test results.

Antibodies to peptidoglycan in patients with spondylarthritis: a clue to disease aetiology?

Although the aetiology of the spondylarthritic diseases, ankylosing spondylitis and Reiter's syndrome, is obscure, a clue to the pathogenesis might be an animal model, adjuvant arthritis. Rats with this disease develop a spectrum of pathology with marked similarity to the spondylarthritides. Since peptidoglycan, a major cell wall component of most bacteria is causally implicated in adjuvant arthritis, we sought evidence that peptidoglycan exposure accompanies both Reiter's syndrome and ankylosing spondylitis. Antibodies to the D-Ala-D-Ala moiety of peptidoglycan were measured by a sensitive and specific ELISA. Antibodies were elevated significantly in patients with ankylosing spondylitis or Reiter's syndrome, but not in patients with rheumatoid arthritis or degenerative joint disease in comparison with normal controls. The findings should be considered preliminary, since only a minority of patients had increased antibody titres. However, the findings are compatible with the hypothesis that peptidoglycan is causally related to spondylarthritis. Antibodies to other moieties in the peptidoglycan molecule might be a more sensitive test for significant exposure.

Detection of soluble peptidoglycan in urine after penicillin administration

A unique enzyme-linked immunosorbent assay was developed to detect soluble peptidoglycans in biological fluids. It makes use of the similar affinities of vancomycin and purified rabbit antibodies to peptidoglycan precursor sequences found in soluble peptidoglycans. This assay has been used to detect as little as 500 pg of soluble peptidoglycan per ml of serum and 5 pg/ml of urine. Studies of normal individuals and Staphylococcus aureus-infected patients revealed only a few sera with detectable levels of soluble peptidoglycans. Studies of normal volunteers who were given a single oral dose of 250 mg of penicillin VK showed that about half had detectable levels of soluble peptidoglycans in their urine up to 6 h after ingestion. This suggests that soluble peptidoglycans can be released by indigenous bacteria in detectable amounts. In one volunteer, a detectable level of soluble peptidoglycan in the urine at 6 h decreased to an undetectable level at 12 h. Such an ephemeral appearance of soluble peptidoglycan in the urine could account for the small number of human sera that had detectable levels of soluble peptidoglycan.

Far-infrared laser scattering studies of density fluctuations in tokamak fusion plasmas

Development of a far-infrared Thomson scattering system for the study of density fluctuations in fusion plasmas is described. New data are presented of naturally occurring low-frequency microturbulence and also of electrostatic modes generated at the ion cyclotron range of frequencies (ICRF). The latter studies are important in understanding ICRF supplementary heating experiments. They have produced the first internal observation of mode-converted ion -Bernstein waves in a tokamak plasma.

A simple washing technique for solid-phase radioimmunoassays and enzyme-linked immunosorbent assays

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High resolution optical ranging system

An optical ranging system which can see through opaque material has been demonstrated. It uses picosecond pulses, generated in a mode-locked dye laser for viewing and, as a very fast gate, a second frequency offset pulse train with a variable delay at the detector. The system could detect a reflection from a mirror inside an opaque mixture with 64-dB round-trip loss and with 1.7-mm range resolution. Transverse resolution of 0.1 mm was also observed. With certain obvious changes in instrumentation this could be converted into a scanning device. The present depth of penetration (round-trip attenuation) would correspond to 0.67 cm in human tissue.

Chromosomal mapping of human creatine kinase (brain type) using human-rodent somatic cell hybrids

Concordant segregation of human brain-type creatine kinase, CK(BB), expression with nucleoside phosphorylase (NP) expression and the presence of chromosome 14 was observed in 53 independently derived cell hybrids between CK(BB)-positive human cells and CK(BB)-negative rodent cells. Further analysis of 26 subclones of two CK(BB)-positive human-mouse cell hybrids confirmed the positive correlation of CK(BB) expression with NP expression. The results suggest that the gene coding for human CK(BB) can be assigned to chromosome 14.

New technique for solid-phase immunoassay: application to hepatitis B surface antigen

I describe a new technique for improving the sensitivity of the solid-phase "sandwich" assay, by using the through-passage receptacle in a novel flow-communication device. The technique allows a large volume of serum to flow through the antibody-coated receptacle repeatedly during the incubation and is thus termed the "flow-through large-volume incubation" method. Binding of 125I-labeled hepatitis B surface antigen to its corresponding antibody on a solid-phase by this method was more rapid and persistent than binding by the conventional method. When the method was applied to the first incubation of the sandwich assay, the test for the antigen was rendered four-, eight-, and 32-fold as sensitive as an accepted third-generation test for the antigen, by incubating 5-mL volumes of serum at (a) room temperature for 18 h, (b) 45 degrees C for 8 h, or (c) room temperature for seven days, respectively.

Thrombotic thrombocytopenic purpura in early pregnancy. Remission after plasma exchange

A 24-year-old Chinese female developed fever, fluctuating neurological and renal manifestations, microangopathic hemolytic anemia, and thrombocytopenia during the 11th week of her first pregnancy. Therapy for thrombotic thrombocytopenic purpura (TTP), initiated during the 15th week of her pregnancy, including corticosteroids, platelet aggregation inhibitors, hysterotomy, and splenectomy was ineffective. However, dramatic improvement and remission occurred after plasma exchange of 3,560 ml was performed with the Haemonetics Model 30 Blood Cell Separator.

New technique for solid-phase immunoassay: application to hepatitis B surface antigen

I describe a new technique for improving the sensitivity of the solid-phase "sandwich" assay, by using the through-passage receptacle in a novel flow-communication device. The technique allows a large volume of serum to flow through the antibody-coated receptacle repeatedly during the incubation and is thus termed the "flow-through large-volume incubation" method. Binding of 125I-labeled hepatitis B surface antigen to its corresponding antibody on a solid-phase by this method was more rapid and persistent than binding by the conventional method. When the method was applied to the first incubation of the sandwich assay, the test for the antigen was rendered four-, eight-, and 32-fold as sensitive as an accepted third-generation test for the antigen, by incubating 5-mL volumes of serum at (a) room temperature for 18 h, (b) 45 degrees C for 8 h, or (c) room temperature for seven days, respectively.

A new plastic receptacle for solid phase immunoassays

A new, simple, inexpensive plastic device for solid phase immunoassay, the through-passage receptacle (TPR), with a large ratio of surface area to volume, is described. It was substantially more efficient in non-specific protein adsorption and specific immunological binding than the conventional wells of microtiter plates. It was also easier to wash since washing was facilitated by a through-passage with a gravity flow. This device, which should be more conducive to automation than currently used receptacles, should increase the sensitivity and decrease the incubation time of the solid phase immunoassay technique.

Studies of the precipitating antibody response in pulmonary aspergillosis

Fractions of <i>Aspergillus fumigatus </i>obtained by DEAE-cellulose chromatography were used for studying the precipitating antibody in sera from four patients with bronchopulmonary aspergillosis (BPA) and in an additional patient with a pulmonary aspergilloma. Three of the 4 BPA sera demonstrated the precipitin reaction with one or more fractions in gel diffusion, but no individual pattern was identical. In order to further evaluate the nature of the precipitating antibody, the mold fractions prior to testing were exposed to either heat, papain, or to reduction and alkylation. The serum from one subject continued to show a precipitin response in gel in spite of antigen treatment, whereas heating and reduction and alkylation abolished a detectable precipitin reaction by the other two sera. Papain had no apparent effect upon any of the antigens tested. In contrast to BPA, the serum from a subject with an aspergilloma contained multiple precipitating antibodies to the mold fractions studied. These antibodies were developed against antigens which showed varying degrees of lability when exposed to either heat or to reduction and alkylation.