Detection of Mycoplasma pneumoniae in serum specimens from patients with mycoplasma pneumonia by PCR

There are few data on detection of Mycoplasma pneumoniae from blood, serum or plasma, and systematic studies on this diagnostic approach in community-acquired pneumonia (CAP) are scarce. Compared to testing respiratory specimens, this approach has the advantages that it is less dependent on proper specimen collection, serum is easily stored and handled, and the pathogen is detected in a primary sterile site, where colonization can be ruled out. In this study, acute-phase serum specimens from 29 patients of Vienna University Hospital (treated between 11/1994 and 6/2004; female: 14, male: 15; median age: 31 years, range: 15-66 years) with CAP and serologically verified M. pneumoniae infection, who had not received anti-mycoplasma therapy prior to serum collection, were tested for M. pneumoniae by conventional PCR and real-time PCR. Conventional PCR yielded negative results for all specimens, but real-time PCR detected M. pneumoniae in 15/29 patient sera (52%). These findings indicate that M. pneumoniae is present in the bloodstream of a substantial proportion of patients with mycoplasma pneumonia. Despite the possible adherence of M. pneumoniae to human erythrocytes, the pathogen can be detected from serum, if a method with enhanced sensitivity is applied. However, the negative predictive value of PCR from serum with regard to etiological diagnosis is low. With regard to the potential clinical benefit of blood-based PCR diagnosis of mycoplasma pneumonia the diagnostic accuracy of this approach using either serum or whole-blood specimens should be addressed by large-scale studies.     

Regulation of MAC-1 (CD11b/CD18) expression on circulating granulocytes in endurance runners

PURPOSE: We tested the hypothesis that degranulation of granulocytes and upregulation of the granulocyte integrin MA-1 (CD11b/CD18) are related to exercise duration and/or intensity. We also investigated whether or not the expression of MAC-1 would be influenced by body temperature or dehydration. Moreover, we tested the hypothesis that changes in leukocyte counts and changes in MAC1 expression with endurance exercise are independently regulated. METHODS: In eight amateur runners, MAC-1 (CD11b/CD18) surface expression on granulocytes was determined by fluorescent antibody cell sorting, before and after an incremental maximal treadmill test, a moderate 3-h run, and a competitive marathon race. RESULTS: Expression CD11b on granulocytes was increased by 10+/-9.6% (P < 0.05) after the maximal treadmill test and by 84+/-76% (P < 0.01) after the marathon run. There was no change in CD11b expression after the moderate 3-h run. CD18 expression was not significantly changed after any of the exercise protocols. CONCLUSION: Expression of CD11b on granulocytes is increased with intense endurance exercise, either incremental maximal treadmill testing or competitive marathon running, but not in moderate endurance training. Thus, exhaustive exercise may be one mechanism for the upregulation of integrin adhesive receptors on granulocytes. This phenomenon could be in part responsible for increased adhesion of granulocytes to endothelial cells and could facilitate tissue infiltration after endurance exercise.     

Diapedesis of leukocytes: antisense oligonucleotides for rescue

Ischemia-reperfusion injury is an acute inflammatory process during which leukocytes are intimately involved. In this review, we summarize the current data on the leukocyte cell adhesion cascade in ischemia-reperfusion injury, focus upon studies which have demonstrated specific cell adhesion molecule interactions which mediate the leukocyte involvement in ischemia-reperfusion injury, and suggest future avenues of therapeutic interventions. The increased adhesion between activated vascular endothelium and peripheral blood leukocytes is central to the structural and the functional impairment in ischemia-reperfusion injury. Several families of adhesion molecules, namely the selectins, the intercellular adhesion molecules (ICAMs), and the integrins expressed either on the endothelium or on the leukocytes, are involved the cascade of events. Sequential and overlapping cellular interactions between the members of the three gene families of adhesion receptors result in adhesion of the leukocytes to the endothelium and extravasation at the site of ischemia. The functional importance of ICAM-1 and its beta2 integrin ligands in ischemia-reperfusion of the kidney has been demonstrated by monoclonal antibody blockade studies, in knockout mice and by treatment with antisense oligodeoxynulceotides (ODN). We have shown that antisense ODN for ICAM-1 protected the kidney against ischemic renal failure. In addition, in transplanted kidneys, ICAM-1 inhibition by antisense ODN ameliorates ischemia-reperfusion injury and prevents delayed graft function. Recent developments in antisense ODN technology make this a promising therapeutic approach, and antisense ODN treatment of donors or donor organs for ICAM-1 may be useful for the prevention of reperfusion injury in human renal transplantation and could influence acute and chronic graft function.     

Mild social stress abolishes the effects of isolation on anxiety and chlordiazepoxide reactivity

  Rationale: Social isolation is anxiogenic and may change the effects of anxiolytic drugs. These effects are generally attributed to ”isolation stress”. However, isolation does not affect basal corticosterone levels; thus, it cannot be considered stressful. On the contrary, isolation deprives animals of mild daily stressors that are inherent to social life. Since mild stressors were shown to be anxiolytic in rats, it was postulated that short-term, repeated stressors may abolish the effects of isolation. Objectives: The aim of the present study was to investigate whether short-term, repeated, mild social stress can abolish the consequences of isolation on anxiety and on the effects of chlordiazepoxide. Methods: Rats were housed in groups or in individual cages for 5 days (isolates). Half of isolates were daily submitted to the attacks of a resident rat for 30 min per day, on 4 consecutive days (stressed isolates). On day 5, rats were treated either with vehicle or with chlordiazepoxide and submitted to the elevated plus-maze test. Endocrinological consequences of experimental manipulations were assessed in a different set of rats. Results: Plasma ACTH and corticosterone levels were similar in the three groups. Weight gain was higher, while plasma growth hormone was lower in stressed isolates, both effects being consistent with a mild stress. Isolation had a clear anxiogenic effect. This effect was completely abolished by the daily experience of social stress. Chlordiazepoxide had a significant anxiolytic effect in all three groups. Its effects on classical plus-maze variables did not differentiate the three groups. However, chlordiazepoxide decreased risk assessment activity only in isolates. Conclusions: The lack of appropriate endocrinological changes challenges the concept of ”isolation stress”. However, isolation was anxiogenic in our study and it also induced subtle changes in the effects of chlordiazepoxide. It appears that mild daily stressors have a protective effect against the effects of isolation. Received: 23 May 1998 / Final version: 3 December 1998     

Characterization of soluble platelet guanylyl cyclase with peptide antibodies

Summary Soluble guanylyl cyclase partially purified from bovine and human platelets was characterized with antibodies raised against synthetic peptides corresponding to different sequences of the ₁- and ₁-subunits of the bovine lung enzyme. On immunoblots, the platelet guanylyl cyclase was recognized by the four antisera used, with the exception of an antiserum against the C-terminus of the ₁-subunit which did not react with the human platelet but with the bovine platelet ₁-subunit. Furthermore the human platelet ₁-subunit exhibited a slightly lower molecular mass than the bovine protein. The C-terminal antibodies precipitated native platelet and lung guanylyl cyclase activity. In contrast an antibody against a peptide out of the putative catalytic domain, which is highly conserved between all guanylyl cyclases sequenced so far, did not precipitate native guanylyl cyclase, although it recognized both subunits on immunoblots, suggesting that the respective amino acid sequence is located in an inner site of the protein.Abbreviations GC_pep2 YGPEVWEDIKKEA (one letter code) - GC_pep3 SRKNTGTEETEQDEN - GC_pep5 VYKVETVGDKYMTVSGLP - GC_pep8 KKDVEEANANFLGKASGID - TBS-T Tris-buffered saline, containing 0.0501o Tween 20 Correspondence to E. Böhme at the above address