Nanosecond pulse generation from a self-injected laser-pumped dye laser using a novel cavity-flipping technique

The observation of regenerative oscillation in a laser-pumped dye laser is reported. Pulse trains of 1-nsec pulses have been observed from a rhodamine 6G dye laser pumped with a 50-nsec pulse at 5320 A. The regenerative oscillation is produced by using a novel cavity-flipping technique recently developed. The principle of this technique and experimental results in a dye laser are described.

Location and structural significance of the oligosaccharides in human Ig-A1 and IgA2 immunoglobulins

The location, number, and kinds of oligosaccharides in human IgA1 and IgA2 immunoglobulins have been determined by amino acid sequence analysis of the alpha heavy chains. Both A2m allotypes of the alpha2 chain of IgA2 have two GlcN oligosaccharides that are absent in the alpha1 chain, but they lack GalN. The A2m(2) allotype has a fifth GlcN oligosaccharide. The alpha chains of IgA proteins also have subclass-specific and allotype-specific differences in amino acid sequence. Although other classes of human immunoglobulins differ in the number and kind of oligosaccharides, the sites are often homologous and are related to the immunoglobulin domain structure. Evolutionary preservation of the tripeptide acceptor sequence for GlcN probably indicates both a structural and biological role for carbohydrate.

Complete covalent structure of a human IgA1 immunoglobulin

The complete covalent structure has been determined for a human myeloma IgA1 immunoglobulin. This protein has unique features in the amino acid sequence and disulfide bridge structure of the variable (V) and constant (C) regions of both the alpha heavy and the lambda light chains, and in the number and loci of oligosaccharides. Whereas C region domains of heavy chains have evolved independently over eons, recent isotypic variations have occured in lambda light chains and possibly in alpha heavy chains.

Antimicrobial factors and bacterial correlation in chronic otitis media with effusion

Analyses of effusions and sera from patients with otitis media with effusion demonstrated local production in the middle ear of lysozyme, IgA and IgG. The effusion IgM was markedly elevated in some patients, also indicating local production. Complement C3 with rare exception was significantly lower in effusions than sera, suggesting utilization of complement in the middle ear, perhaps in conjunction with antibodies. The presence of high levels of lysozyme and immunoglobulins in effusions correlates with the low isolation rate of microorganisms in culture and may influence survival of organisms in the middle ear.

Microorganisms in chronic otitis media with effusion

A total of 175 effusions obtained from 172 patients suffering from chronic otitis media with effusions was examined for bacterial smear and culture. Eighty percent showed positive bacterial smear, but only 49% yielded positive bacterial culture. The mucoid effusions had positive cultures in only 37%, whereas the bacterial culture rate was higher in serous (59%) and leukocytic (64%) types. The isolation of common pathogens accounted for about 50% of the isolates, and nonpathogens accounted for the remaining 50%. The high incidence of microorganisms in the middle ear effusions in the present series raises the possibility of bacterial contribution in many cases of OME.

Immunoglobulin E in chronic middle ear effusions

A total of 61 middle ear effusions and matched sera obtained from patients suffering from chronic otitis media with effusions (OME) was examined for IgE and other immunoglobulins to see if a reaginic antibody is involved in OME. The IgE levels were determined by the Phadebas IgE radioimmunoassay test. Excluding one patient who had extremely high IgE as a result of parasitosis, there were only three cases which showed marginally increased serum IgE levels. Elevated IgE levels in sera and/or in effusions were unrelated to a history of allergy. The mucoid effusions had significantly higher effusion levels than the levels in corresponding sera (p less than .0005). Fourteen percent of the cases examined showed effusion IgE levels five times or more higher than serum levels. Biopsy specimens of these patients showed numerous degranulating mast cells. Only two specimens showed eosinophilic infiltration. It is suggested that the IgE is produced locally by the mucosa in mucoid-type effusions and may have been involved in mast cell degranulation. However, this study cannot confirm the allergic nature of the OME.

Structure, function, and evolutionary relationships of Fc domains of human immunoglobulins A, G, M, and E

Human immunoglobulins, A, G, M, and E have strong homology in amino acid sequence (about 30 percent) distributed nonuniformly throughout the Fc region. Immunoglobulins M are A are least alike in the first Fc domain and most alike in the second. Individual domains of heavy chains have evolved with different mutation rates but with conservation of essential structural features. No relation of primary structure to complement binding ability is apparent.

Secretory lysozyme of the human middle ear mucosa: immunocytochemical localization

Lysozyme was demonstrated by an immunocytochemical technique in the biopsied mucosa obtained from the promontory of the fifteen patients who had chronic middle ear effusions. Lysozyme was localized in the mucigen granules of the secretory cells, as well as in the specific granules of the polymorphonuclear neutrophilic leukobytes (PMN) and macrophages. The specimens obtained from patients with mucous effusion showed numerous secretory cells that contained lysozyme, in sharp contrast to the serous type in which only a few secretory cells could be found. The present morphological finding was in agreement with the biochemical finding which demonstrated higher lysozyme level in mucous effusions than that of the serous type. It was concluded that human middle ear mucosa provided lysozyme and that its secretion was active in serous otitis media, particularly of mucoid type.

Chronic middle ear effusions. Immunochemical and bacteriological investigations

Middle ear effusions from 100 patients (ages 6 months to 10 years) with serous otitis media were examined. The IgA, IgG, and lysozyme were demonstrated at a higher level in the effusions than the corresponding sera, indicating local production. The mucoid type contained higher level of immunoglobulins and lysozyme compared to serous type effusions. Bacteria were found in 77 percent of the effusions by means of a smear, and 52 percent yielded positive bacterial culture. The incidence of positive culture in effusions of the patients less than 6 years of age was 60 percent, while the group older than 6 years old was 32%, and the group over 8 was only 22 percent. Bacterial recovery rate was inversely related to the dramatic increase with age of IgA and IgG and lysozyme levels in effusions.

Laser isotope separation using two-photon selective excitation; its quantum efficiency and separation factor

Application of two-photon selective excitation to isotope separation with high power, high resolution tunable lasers is discussed. A simple kinetic model is given to determine quantum efficiency and separation factor in terms of laser powers and relaxation constants. A numerical example is used to demonstrate the feasibility of the scheme. Results indicate that a high quantum yield is obtainable with the optical technique.