Streptococcal Pyrogenic Exotoxin B Enhances Tissue Damage Initiated by OtherStreptococcus pyogenesProducts

M. Saouda; W. Wu; P. Conran; M. D. P. Boyle

doi:10.1086/323083

Role of Streptococcal Pyrogenic Exotoxin B in the Mouse Model of Group A Streptococcal Infection

Infection and Immunity ◽

10.1128/iai.66.8.3931-3935.1998 ◽

1998 ◽

Vol 66 (8) ◽

pp. 3931-3935 ◽

Cited By ~ 95

Author(s):

Chih-Feng Kuo ◽

Jiunn-Jong Wu ◽

Kuei-Yuan Lin ◽

Pei-Jane Tsai ◽

Shiour-Ching Lee ◽

...

Keyword(s):

Mouse Model ◽

Cysteine Protease ◽

Tissue Damage ◽

Tissue Injury ◽

Lethal Dose ◽

Neutrophil Infiltration ◽

Group A ◽

Streptococcal Pyrogenic Exotoxin B ◽

Spe B

ABSTRACT Streptococcal pyrogenic exotoxin B (SPE B) is a cysteine protease produced by Streptococcus pyogenes. In this study, the differences in virulence between protease-positive clinical isolates and their protease-negative mutants were examined in a mouse model. Isogenic protease-negative mutants were constructed by homologous recombination, using integrational plasmids to disrupt thespeB gene. These mutants caused less mortality and tissue damage than protease-positive strains when inoculated into BALB/c mice via air pouch, suggesting that SPE B cysteine protease plays an important role in the pathogenesis of S. pyogenesinfection. Reconstitution of SPE B in the air pouches increased the mortality of mice receiving the speB mutant strain. Infiltrated cell numbers in the exudates from the air pouches of mice infected with SPE B-producing S. pyogenes were higher than those from mice infected with protease-negative mutants at 12 h. However, despite pretreatment with vinblastine to deplete neutrophils, injection of protease-positive bacteria still resulted in severe tissue injury, indicating that neutrophil infiltration may not be the major factor involved in SPE B-enhanced tissue damage. The role of SPE B was further confirmed by demonstrating that SPE B immunization of mice conferred protection from challenge with a lethal dose of protease-positive bacteria.

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Artifacts caused by dehydration and epoxy embedding in TEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010008599x ◽

1991 ◽

Vol 49 ◽

pp. 338-339

Author(s):

Hilton H. Mollenhauer

Keyword(s):

Electron Microscopy ◽

Electron Beam ◽

Volume Change ◽

Tissue Damage ◽

Beam Specimen ◽

Chemical Fixation ◽

Resin Impregnation ◽

Storage Vesicles ◽

A Cell ◽

Tissue Shrinkage

Various means have been devised to preserve biological specimens for electron microscopy, the most common being chemical fixation followed by dehydration and resin impregnation. It is intuitive, and has been amply demonstrated, that these manipulations lead to aberrations of many tissue elements. This report deals with three parts of this problem: specimen dehydration, epoxy embedding resins, and electron beam-specimen interactions. However, because of limited space, only a few points can be summarized.Dehydration: Tissue damage, or at least some molecular transitions within the tissue, must occur during passage of a cell or tissue to a nonaqueous state. Most obvious, perhaps, is a loss of lipid, both that which is in the form of storage vesicles and that associated with tissue elements, particularly membranes. Loss of water during dehydration may also lead to tissue shrinkage of 5-70% (volume change) depending on the tissue and dehydrating agent.

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Ultrastructure and analytical microprobe analysis of simian lung mite pigments

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143249 ◽

1986 ◽

Vol 44 ◽

pp. 324-325

Author(s):

R. W. Cole ◽

J. C. Kim

Keyword(s):

Biomedical Research ◽

Tissue Damage ◽

Microprobe Analysis ◽

Old World Monkeys ◽

Old World ◽

Experimental Animals ◽

The Past ◽

Lung Mite ◽

Mite Infestations ◽

Cardiopulmonary System

In recent years, non-human primates have become indispensable as experimental animals in many fields of biomedical research. Pharmaceutical and related industries alone use about 2000,000 primates a year. Respiratory mite infestations in lungs of old world monkeys are of particular concern because the resulting tissue damage can directly effect experimental results, especially in those studies involving the cardiopulmonary system. There has been increasing documentation of primate parasitology in the past twenty years.

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