Enzyme-linked immunosorbent assay for detection of specific antibodies to Ureaplasma urealyticum serotypes

Optimal conditions of a micro-enzyme-linked immunosorbent assay system for the detection of immunoglobulin G antibodies to Ureaplasma urealyticum were established with rabbit antisera. Initially, the antisera, raised against eight U. urealyticum serotypes grown on medium containing horse serum, displayed nonspecific reactions with our enzyme-linked immunosorbent assay antigens. Substitution of fetal bovine serum in the medium eliminated this nonspecificity. The assay was then serotype-specific for the original eight U. urealyticum serotypes. The prominent homologous reaction was easily differentiated from the heterologous reactions. A one-way cross-reaction was observed with serotype 2 antiserum and serotype 5 antigen. The results were reproducible and could be obtained in 4 h with only 10 microliters of serum for eight serotypes. Optimal antigen concentrations for the U. urealyticum serotypes ranged from 0.40 to 1.60 micrograms/ml. Our results indicated that enzyme-linked immunosorbent assay has the potential for the detection of antibodies to specific serotypes of U. urealyticum.

Rows of dimeric-particles within the axolemma and juxtaposed particles within glia, incorporated into a new model for the paranodal glial-axonal junction at the node of Ranvier

Using freeze-fracture techniques, we have analyzed the glial-axonal junction (GAJ) between Schwann cells and axons in the peripheral nervous system, and between oligodendrocytes and axons in the central nervous system of the rat. We have identified a new set of dimeric-particles arranged in circumferential rows within the protoplasmic fracture faces (P-faces) of the paranodal axolemma in the region of glial-axonal juxtaposition. These particles, 260 A in length, composed of two 115-A subunits, are observed in both aldehyde-fixed and nonfixed preparations. The rows of dimeric-particles within the axonal P-face are associated with complementary rows of pits within the external fracture face (E-face) of the paranodal axolemma. These axonal particles are positioned between rows of 160-A particles that occur in both fracture faces of the glial loops in the same region. We observed, in addition to these previously described 160-A particles, a new set of 75-A glial particles within the glial P-faces of the GAJ. These 75-A particles form rows that are centered between the rows of 160-A particles and are therefore superimposed over the rows of dimeric-particles within the paranodal axolemma. Our new findings are interpreted with respect to methods of specimen preparation as well as to a potential role for the paranodal organ in saltatory conduction. We conclude that this particle-rich junction between axon and glia could potentially provide an intricate mechanism for ion exchange between these two cell types.

Observations on the human corpus luteum: histochemical changes during development and involution

Morphologic studies of the developing, gestational, and involuting corpus luteum show that rapid structural changes occur and that involution is not associated with an appropriate inflammatory response. Histochemical techniques were used to demonstrate several patterns of enzyme activity. The luteunized granulosa cells stained with increasing intensity for lactic dehydrogenase, succinic dehydrogenase, cytochrome oxidase, glucose-6-phosphatase, and 3 beta-hydroxysteroid dehydrogenase, but reactivity for these enzymes dropped markedly with early involution, and staining was never conspicuous in the organizing cavity. Reactions for acid phosphatase, glucosaminidase, galactosidase, glucuronidase, and nonspecific esterase were also present in the developing corpus luteum, but staining decreased more slowly during involution and was prominent in the occasional macrophages in the granulosa and the granulation tissue in the cavity. Staining was moderately intense for all of the enzymes in the corpus luteum of pregnancy. The decrease in activity for these metabolic enzymes confirms the histologic impression of degeneration, but the loss of staining for lysosomal enzymes was more rapid than expected. The latter finding complicates the hypothesis of involution of involution of the corpus luteum as an example of programmed cell death.