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Biomedical subjects

J Jahn

Publications and source records attributed to J Jahn.

At least 19 recordsLinked to original sources
PubMed2004

CD14 promoter polymorphism -159C>T is associated with susceptibility to chronic Chlamydia pneumoniae infection in peripheral blood monocytes.

Chlamydia pneumoniae uses peripheral blood monocytes (PBMC) for systemic dissemination and has been linked to atherogenesis by inflammation mediated via TLR2/4 and CD14. We found 12.8% of 610 coronary artery disease (CAD) patients of Central European background to be chronically infected with C. pneumoniae based on the repeated detection of chlamydial DNA in PBMC. Among those the -159C>T CD14 promoter polymorphism was more frequent (OR 1.7, 95% CI 1.08-2.65, P=0.0224) than among C. pneumoniae-negative subjects matched for age and gender. The Arg753Gln TLR2 and Asp299Gly TLR4 polymorphisms were not related to chlamydial infection. Susceptibility for chronic chlamydial infection of PBMC in CAD patients appears associated with the CD14-159C>T promoter polymorphism encoding for enhanced CD14 expression.

Antibodies, Bacterial↗
PubMed2001

Chlamydia pneumoniae infection in circulating human monocytes is refractory to antibiotic treatment.

BACKGROUND: Recovery of the intracellular bacterium Chlamydia pneumoniae from atherosclerotic plaques has initiated large studies on antimicrobial therapy in coronary artery disease. The basic concept that antibiotic therapy may eliminate and prevent vascular infection was evaluated in vitro and in vivo by examining the antibiotic susceptibility of C pneumoniae in circulating human monocytes, which are thought to transport chlamydiae from the respiratory tract to the vascular wall. METHODS AND RESULTS: Blood monocytes (CD14+) from 2 healthy volunteers were obtained before and after oral treatment with azithromycin or rifampin and then inoculated with a vascular C pneumoniae strain and continuously cultured in the presence of the respective antibiotic. Progress of infection and chlamydial viability was assessed by immunogold-labeling and detection of C pneumoniae-specific mRNA transcripts. Circulating monocytes from patients undergoing treatment with experimental azithromycin for coronary artery disease were examined for C pneumoniae infection by cell culture. Antibiotics did not inhibit chlamydial growth within monocytes. Electron microscopy showed development of chlamydial inclusion bodies. Reverse transcription-polymerase chain reaction demonstrated continuous synthesis of chlamydial mRNA for 10 days without lysis of the monocytes. The in vivo presence of viable pathogen not eliminated by azithromycin was shown by cultural recovery of C pneumoniae from the circulating monocytes of 2 patients with coronary artery disease. CONCLUSIONS: C pneumoniae uses monocytes as a transport system for systemic dissemination and enters a persistent state not covered by an otherwise effective antichlamydial treatment. Prevention of vascular infection by antichlamydial treatment may be problematic: circulating monocytes carrying a pathogen with reduced antimicrobial susceptibility might initiate reinfection or promote atherosclerosis by the release of proinflammatory mediators.

Aged↗
PubMed2001

[Infection hypothesis of coronary heart disease].

It is well accepted that coronary artery disease is linked to an inflammatory process. It is unproven however whether either infectious agents may cause or accelerate coronary artery disease or the inflammatory process is due to metabolic or toxic effects. Among the possible infectious agents Chlamydia pneumoniae is the most likely bacterium involved in atherosclerosis. The arguments in favour of Chlamydia pneumoniae originate from seroepidemiologic studies and from detection and isolation of bacteria from vascular lesions. This review summarises the present understanding of the role of bacterial infection for development or progression of coronary artery disease.

Animals↗
PubMed2000

Coronary artery disease: an inflammatory or infectious process.

It is well accepted that coronary artery disease is linked to an inflammatory process. It is unknown which agents may cause or accelerate coronary artery disease. An inflammation of the vessel wall may be caused by a number of mechanisms such as accumulation of glycosylated proteins in diabetic patients, oxidised LDL in patients with hypercholesterolemia or infectious agents. Among the possible infectious agents Chlamydia pneumoniae is the most likely microorganism involved in atherosclerosis. The arguments in favour of Chlamydia pneumoniae result from seroepidemiologic studies and from detection of chlamydial DNA in atherosclerotic plaques by polymerase chain reaction (PCR). In addition this microorganism is the only one that could be isolated from atherosclerotic tissue. This review summarises the present understanding of the role of an inflammatory process in the development or progression of coronary artery disease.

Acute-Phase Proteins↗
PubMed2000

Detection of Chlamydia pneumoniae within peripheral blood monocytes of patients with unstable angina or myocardial infarction.

Because individual diagnoses of vascular infection with Chlamydia pneumoniae depend entirely on surgically removed tissues, a better assay to predict vascular infection is needed. Polymerase chain reaction detection of chlamydial DNA was applied to CD14-positive cells collected from 238 patients with angiographically identified unstable angina or acute myocardial infarction. C. pneumoniae was detected in 52 (28%) of 188 persons with unstable angina and in 13 (26%) of 50 persons with myocardial infarction. Differences between groups were not significant. C. pneumoniae is present in monocytes/macrophages of a significant proportion of persons with progressive coronary artery disease. Infarction is not accompanied by a rise in chlamydial detection rates. The potential role of chlamydiae in coronary atherosclerosis may therefore be more related to acceleration of disease or systemic effects by persistent infection than to sudden initiation of infarction by acute infection.

Adult↗
PubMed1999

Filamentous intranuclear inclusion bodies in psittacine birds. A structural and ultrastructural study.

This paper concerns a disease affecting a group of African grey parrots, which involves intranuclear inclusion bodies composed of filamentous material. The disease was characterized by either sudden death or death within 2-3 days from onset of non-specific symptoms. At necropsy, gross lesions included enlarged liver, mild hepatic congestion and focal necrosis. Samples from five birds were fixed in 10% formol and routinely processed for light and electron microscopy. In four birds, numerous hepatocytes displayed an enlarged nucleus, with peripheral margination of chromatin; the nucleus was partially or wholly filled by a basophilic inclusion body. In the remaining bird, inclusion bodies were acidophilic and completely filled the nucleus; nuclear enlargement was less evident than in the other birds. At ultrastructural examination, and in both types of IIB, nuclei contained looped filaments but no evidence of viral structures. However, virion-like structures were observed in the cytoplasm of some hepatocytes.

Animals↗
PubMed1994

Psychometric testing in rats during normal ageing. Procedures and results.

Examples are given for assessing parameters for motor activity learning and memory. By using the method of the open field the authors could verify that motor activity decreases with age and that it underlies obviously endogenous rhythms which undergo age dependent alterations (e.g. diminution of the amplitude). From the results of an investigation on the influence of ageing and stress on learning ability and memory of the rat the authors draw the following conclusions: Learning ability declines with advancing age. The effect of ageing on memory could not be clearly shown. The effect of the stressors used (crowding and noise) seems to depend on the season of the year (circannual biorhythm).

Aging↗
PubMed1993

[The hematologic parameters, concentrations of minerals and metabolic products and activities of enzymes in sheep].

In the period of March 1988-March 1989, in 20 Lower Austrian sheep breeding farms blood samples were taken in two-month intervals from sheep of the following breeds: 130 Tyrolean Mountain sheep, 59 German Improved Land breed, 59 East Friesian and 57 German Blackheaded Mutton breed sheep. The following standards for sheep were evaluated: Erythrocytes 7,2-11,9 T/L, haematocrit 0,25-0,41 1/L, haemoglobin 82-147 g/L, lymphocytes 34-80%, segmented neutrophils 10-53%, band neutrophils 1-3%, eosinophilic granulocytes 0-24%, basophilic granulocytes 0-1%, monocytes 0-1%, calcium 1,8-2,8 mmol/L, phosphorus 1,0-2,6 mmol/L, magnesium 0,6-1,3 mmol/L, total protein 53-81 g/L, albumin 22-41 g/L, aspartate aminotransferase 27-81 U/L, alanine aminotransferase 3-25 U/L, gamma glutamic transaminase 24-59 U/L, alkaline phosphatase 44-355 U/L, creatine kinase 3-130 U/L, glutamic dehydrogenase 2,0-36,5 U/L, total bilirubin 0,7-5,1 mumol/L, cholesterol 1,1-3,2 mmol/l, urea nitrogen 1,3-12,7 mmol/l, creatinine 50-112 mumol/L. Apart from that, additional standards for the mentioned breeds of sheep were evaluated, revealing significant differences. Also the age and the time of the year proved to have an influence upon the ascertained blood values.

Age Factors↗