scholarly journals Characterization of Transmission of Pneumocystis carinii f. sp. muris through Immunocompetent BALB/c Mice

2003 ◽  
Vol 71 (7) ◽  
pp. 3852-3856 ◽  
Author(s):  
F. Gigliotti ◽  
A. G. Harmsen ◽  
T. W. Wright
Keyword(s):  
Pneumocystis Carinii ◽  
Opportunistic Pathogen ◽  
Lung Compliance ◽  
Scid Mice ◽  
Symptomatic Infection ◽  
Normal Host ◽  
Active Replication ◽  
Immunocompetent Mice ◽  
Dynamic Lung Compliance

ABSTRACT By using mouse models, it has been shown that Pneumocystis carinii f. sp. muris can be transmitted to immunocompetent mice that are exposed to immunosuppressed mice with active P. carinii pneumonia. We sought to determine whether P. carinii f. sp. muris could be transmitted between normal mice. The rationale for these experiments was to demonstrate whether the normal host could serve as the reservoir of organisms that produce Pcp when the organism is acquired by the immunosuppressed host. Under the conditions of these experiments, normal mice are able to be infected by brief cohousing with P. carinii-infected SCID mice. There was active replication of organisms in the normal host such that the organism could be transmitted to other normal mice, again with active replication. Mice that had seroconverted after exposure to P. carinii-infected SCID mice were more resistant to infection when reexposed. Infection in normal mice was well tolerated with minimal effects on dynamic lung compliance. We speculate, based on these results, that transmission from normal host to normal host, as an asymptomatic or minimally symptomatic infection, could be a way to maintain this opportunistic pathogen in the environment.

scholarly journals The cloning and characterization of the arom gene of Pneumocystis carinii

1993 ◽  
Vol 139 (12) ◽  
pp. 2901-2914 ◽  
Author(s):  
S. Banerji ◽  
A. E. Wakefield ◽  
A. G. Allen ◽  
D. J. Maskell ◽  
S. E. Peters ◽  
...  
Keyword(s):  
Pneumocystis Carinii

A 55 kDa antigen of Pneumocystis carinii: analysis of the cellular immune response and characterization of the gene

1993 ◽  
Vol 7 (5) ◽  
pp. 745-753 ◽  
Author(s):  
A. G. Smulian ◽  
S. A. Theus ◽  
N. Denko ◽  
P. D. Walzer ◽  
J. R. Stringer
Keyword(s):  
Immune Response ◽  
Cellular Immune Response ◽  
Pneumocystis Carinii ◽  
Cellular Immune

LUNG FUNCTION AND PATHOLOGY IN A PREMATURE INFANT WITH CHRONIC PULMONARY INSUFFICIENCY (WILSON-MIKITY SYNDROME)

PEDIATRICS ◽  
1967 ◽  
Vol 40 (6) ◽  
pp. 962-974
Author(s):  
W. A. Aherne ◽  
K. W. Cross ◽  
E. N. Hey ◽  
Sheila R. Lewis
Keyword(s):  
Lung Function ◽  
Premature Infant ◽  
Lung Biopsy ◽  
Signs And Symptoms ◽  
Lung Compliance ◽  
Alveolar Ventilation ◽  
Pulmonary Insufficiency ◽  
Normal Limits ◽  
Dynamic Lung Compliance ◽  
Symptoms And Signs

Detailed lung function studies at the age of 8 months and 1 year are reported for an infant who weighed 992 gm at birth and who developed chronic progressive pulmonary insufficiency 2 weeks after birth. The symptoms and signs were similar to those described by Wilson and Mikity in 1960. A confirmatory lung biopsy was obtained when the child was 11 months old. Dynamic lung "compliance" was very significantly reduced while a static estimate of lung compliance was within normal limits. These and other lung function findings are interpreted as indicating that uneven alveolar ventilation was the probable functional basis for all the signs and symptoms observed.

Dynamic lung compliance in newborn and adult cats

1986 ◽  
Vol 60 (3) ◽  
pp. 743-750 ◽  
Author(s):  
K. J. Sullivan ◽  
J. P. Mortola
Keyword(s):  
Stress Relaxation ◽  
Transpulmonary Pressure ◽  
Lung Compliance ◽  
Theoretical Treatment ◽  
The Difference ◽  
Adult Cats ◽  
Isolated Lungs ◽  
Dynamic Lung Compliance ◽  
Volume History ◽  
Lung Stress

Static (Cstat) and dynamic (Cdyn) lung compliance and lung stress relaxation were examined in isolated lungs of newborn kittens and adult cats. Cstat was determined by increasing volume in increments and recording the corresponding change in pressure; Cdyn was calculated as the ratio of the changes in volume to transpulmonary pressure between points of zero flow at ventilation frequencies between 10 and 110 cycles/min. Lung volume history, end-inflation volume, and end-deflation pressure were maintained constant. At the lowest frequency of ventilation, Cdyn was less than Cstat, the difference being greater in newborns. Between 20 and 100 cycles/min, Cdyn of the newborn lung remained constant, whereas Cdyn of the adult lung decreased after 60 cycles/min. At all frequencies, the rate of stress relaxation, measured as the decay in transpulmonary pressure during maintained inflation, was greater in newborns than in adults. The frequency response of Cdyn in kittens, together with the relatively greater rate of stress relaxation, suggests that viscoelasticity contributes more to the dynamic stiffening of the lung in newborns than in adults. A theoretical treatment of the data based on a linear model of viscoelasticity supports this conclusion.

Lung dysfunction after thermal injury in relation to prostanoid and oxygen radical release

1986 ◽  
Vol 61 (1) ◽  
pp. 103-112 ◽  
Author(s):  
L. J. Jin ◽  
C. Lalonde ◽  
R. H. Demling
Keyword(s):  
Lipid Peroxidation ◽  
Lung Tissue ◽  
Lipid Peroxide ◽  
Lung Compliance ◽  
Base Line ◽  
Lung Water ◽  
Control Value ◽  
Lung Dysfunction ◽  
Dynamic Lung Compliance ◽  
Lung Lymph

We studied whether changes in lung function after burns (1- to 12-h period) were due to changes in lung water or airways resistance and the relationship of the changes to prostanoid and O2 radical activity (measured as lipid peroxidation). Twenty-five anesthetized mechanically ventilated adult sheep were given a 40% of body surface scald burn and resuscitated to restore and maintain base-line filling pressures. Dynamic lung compliance (Cdyn) decreased by 40% from 38 +/- 5 to 24 +/- 4 ml/cmH2O at 12 h. Venous thromboxane B2 transiently increased from 210 +/- 40 to 1,100 +/- 210 pg/ml, and the value in lung lymph increased from 180 +/- 80 to 520 +/- 80 pg/ml. Prostacyclin levels in lung lymph and plasma remained at base line. Protein-poor lung lymph flow increased two- to threefold, but postmortem lung analysis revealed no increase in lung water from the control of 3.5 +/- 0.3 g H2O/g dry wt. No increase in protein permeability was seen. However, the lipid peroxidation of lung tissue measured as malondialdehyde was significantly increased from the control value of 56 +/- 4 nmol/g lung to a value of 69 +/- 6. Ibuprofen pretreatment (12.5 mg/kg) markedly attenuated the decrease in Cdyn, with the value at 12 h being 90% of base line. Ibuprofen also decreased the amount of lung lipid peroxidation but did not decrease the lung lymph response. We conclude that the decrease in Cdyn seen early postburn is not due to increased lung water, but, rather, is due to a mediator-induced bronchoconstriction, attenuated by ibuprofen; the mediator being either thromboxane or a byproduct of O2 radicals as evidenced by increased lipid peroxide production in lung tissue.

scholarly journals Identification and Characterization of Quorum-Quenching Activity of N-Acylhomoserine Lactonase from Coagulase-Negative Staphylococci

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 483
Author(s):  
Tomohiro Morohoshi ◽  
Yaoki Kamimura ◽  
Nobutaka Someya
Keyword(s):  
Quorum Sensing ◽  
Opportunistic Pathogen ◽  
Quorum Quenching ◽  
Coagulase Negative Staphylococci ◽  
Sensing Systems ◽  
Genes Encoding ◽  
Acyl Chains ◽  
Gene Homologue ◽  
Identification And Characterization

N-Acylhomoserine lactones (AHLs) are used as quorum-sensing signals in Gram-negative bacteria. Many genes encoding AHL-degrading enzymes have been cloned and characterized in various microorganisms. Coagulase-negative staphylococci (CNS) are present on the skin of animals and are considered low-virulent species. The AHL-lactonase gene homologue, ahlS, was present in the genomes of the CNS strains Staphylococcus carnosus, Staphylococcus haemolyticus, Staphylococcus saprophyticus, and Staphylococcus sciuri. We cloned the candidate ahlS homologue from six CNS strains into the pBBR1MCS5 vector. AhlS from the CNS strains showed a higher degrading activity against AHLs with short acyl chains compared to those with long acyl chains. AhlS from S. sciuri was expressed and purified as a maltose-binding protein (MBP) fusion. Pseudomonas aeruginosa is an opportunistic pathogen that regulates several virulence factors such as elastase and pyocyanin by quorum-sensing systems. When MBP-AhlS was added to the culture of P. aeruginosa PAO1, pyocyanin production and elastase activity were substantially reduced compared to those in untreated PAO1. These results demonstrate that the AHL-degrading activity of AhlS from the CNS strains can inhibit quorum sensing in P. aeruginosa PAO1.

scholarly journals Infection of SCID mice with Montana Myotis leukoencephalitis virus as a model for flavivirus encephalitis

2002 ◽  
Vol 83 (8) ◽  
pp. 1887-1896 ◽  
Author(s):  
Nathalie Charlier ◽  
Pieter Leyssen ◽  
Jan Paeshuyse ◽  
Christian Drosten ◽  
Herbert Schmitz ◽  
...  
Keyword(s):  
Yellow Fever Virus ◽  
Antiviral Agents ◽  
Antiviral Drug ◽  
Vero Cells ◽  
Scid Mice ◽  
Fever Virus ◽  
Viral Rna ◽  
Interferon Α ◽  
Immunocompetent Mice ◽  
Antiviral Targets

We have established a convenient animal model for flavivirus encephalitis using Montana Myotis leukoencephalitis virus (MMLV), a bat flavivirus. This virus has the same genomic organization, and contains the same conserved motifs in genes that encode potential antiviral targets, as flaviviruses that cause disease in man (N. Charlier et al., accompanying paper), and has a similar particle size (approximately 40 nm). MMLV replicates well in Vero cells and appears to be equally as sensitive as yellow fever virus and dengue fever virus to a selection of experimental antiviral agents. Cells infected with MMLV show dilation of the endoplasmic reticulum, a characteristic of flavivirus infection. Intraperitoneal, intranasal or direct intracerebral inoculation of SCID mice with MMLV resulted in encephalitis ultimately leading to death, whereas immunocompetent mice were refractory to either intranasal or intraperitoneal infection with MMLV. Viral RNA and/or antigens were detected in the brain and serum of MMLV-infected SCID mice, but not in any other organ examined: MMLV was detected in the olfactory lobes, the cerebral cortex, the limbic structures, the midbrain, cerebellum and medulla oblongata. Infection was confined to neurons. Treatment with the interferon-α/β inducer poly(I)·poly(C) protected SCID mice against MMLV-induced morbidity and mortality, and this protection correlated with a reduction in infectious virus titre and viral RNA load. This validates the MMLV model for use in antiviral drug studies. The MMLV SCID model may, therefore, be attractive for the study of chemoprophylactic or chemotherapeutic strategies against flavivirus infections causing encephalitis.

scholarly journals Acquisition of multidrug resistance transposon Tn6061 and IS6100-mediated large chromosomal inversions in Pseudomonas aeruginosa clinical isolates

Microbiology ◽  
2010 ◽  
Vol 156 (5) ◽  
pp. 1448-1458 ◽  
Author(s):  
Sébastien Coyne ◽  
Patrice Courvalin ◽  
Marc Galimand
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Multidrug Resistance ◽  
Opportunistic Pathogen ◽  
Clinical Isolates ◽  
Chromosomal Inversions ◽  
Gene Acquisition ◽  
Drug Classes ◽  
Horizontal Acquisition

Pseudomonas aeruginosa is a major human opportunistic pathogen, especially for patients in intensive care units or with cystic fibrosis. Multidrug resistance is a common feature of this species. In a previous study we detected the ant(4′)-IIb gene in six multiresistant clinical isolates of P. aeruginosa, and determination of the environment of the gene led to characterization of Tn6061. This 26 586 bp element, a member of the Tn3 family of transposons, carried 10 genes conferring resistance to six drug classes. The ant(4′)-IIb sequence was flanked by directly repeated copies of ISCR6 in all but one of the strains studied, consistent with ISCR6-mediated gene acquisition. Tn6061 was chromosomally located in six strains and plasmid-borne in the remaining isolate, suggesting horizontal acquisition. Duplication-insertion of IS6100, that ended Tn6061, was responsible for large chromosomal inversions. Acquisition of Tn6061 and chromosomal inversions are further examples of intricate mechanisms that contribute to the genome plasticity of P. aeruginosa.

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