Kenneth M Persson

High Prevalence of Chlamydia pneumoniae DNA in Peripheral Blood Mononuclear Cells in Patients with Cardiovascular Disease and in Middle-Aged Blood Donors

Nested polymerase chain reaction (nPCR) demonstrated the presence of Chlamydia pneumoniae-specific DNA in peripheral blood mononuclear cells (PBMC). PBMC samples were obtained from 103 consecutive patients (62 male, 41 female) aged 22-85 years (mean, 64) admitted for coronary angiography because of suspected coronary heart disease and from 52 blood donors (43 male, 9 female) aged 40-64 years (mean, 49). Of the 101 evaluable patients, 60 (59%) were identified by nPCR assay as C. pneumoniae DNA carriers; C. pneumoniae-specific microimmunofluorescence (MIF) serology confirmed exposure to the bacterium in 57 (95%) of the 60 nPCR-positive patients. Among the 52 blood donors, the nPCR assay identified 24 (46%) C. pneumoniae DNA carriers, all of whom were positive by C. pneumoniae-specific serology. Thirty-two patients (32%) and 23 blood donors (44%) were MIF antibody-positive but repeatedly nPCR-negative; Bartonella henselae- or Bartonella quintana-specific antibodies were not detected among any of these subjects. In this study, C. pneumoniae DNA was common in PBMC of patients with coronary heart disease and in middle-aged blood donors.

Chlamydia trachomatis infection and persistence of human papillomavirus

Human papillomavirus (HPV) persistence is the major cause of cervical cancer, but most HPV infections will not persist and risk factors for HPV persistence are not well known. Chlamydia (C.) trachomatis infection seems to also be associated with cervical cancer. We investigated whether C. trachomatis infection is a risk factor for HPV persistence. In a cohort of 12,527 women participating in a population‐based HPV screening trial in Sweden, 6,418 women completed testing for HPV DNA by general primer PCR and typing by reverse dot blot hybridization. On average 19 months later, 303 women that had been HPV‐positive and had normal cytology at enrollment completed a new HPV test. Environmental exposures were assessed by an 87‐item questionnaire. Previous sexually transmitted infections were also investigated by serology. At follow‐up, 44% of the women were positive for the same type of HPV DNA as at enrollment. Persistence correlated with length of follow‐up (p < 0.01) and condom use seemed to protect against HPV persistence (p < 0.05). The most significant risk factor for persistent presence of HPV DNA was self‐reported history of previous C. trachomatis infection (relative risk in multivariate model = 2.09; 95% confidence interval = 1.05–4.18). We conclude that persistence of oncogenic HPV infections is more likely among women with a previous C. trachomatis infection.

Current Infection With Helicobacter pylori, but Not Seropositivity to Chlamydia pneumoniae or Cytomegalovirus, Is Associated With an Atherogenic, Modified Lipid Profile

Abstract —Infectious agents may be involved in atherothrombogenesis. The potential pathogenic pathway, however, remains unclear. We investigated the association between various infectious agents and lipoproteins known to have an atherogenic effect. We recruited 470 healthy blood donors and 238 patients with angiographically proven coronary heart disease (CHD), aged 40 to 68 years. Seropositivity to Chlamydia pneumoniae (CP), chlamydial lipopolysaccharide, and cytomegalovirus (CMV) was determined; infection with Helicobacter pylori (HP) was assessed by using the [13C]urea breath test. In all subjects, total cholesterol, high density lipoprotein (HDL) cholesterol, lipoprotein(a), and various apolipoproteins (apos) were determined. In unadjusted analysis, mean HDL cholesterol concentration was significantly decreased in HP-positive healthy subjects (1.36 vs 1.44 mmol/L, P =0.006) compared with HP-negative subjects. The HDL cholesterol to total cholesterol ratio was significantly decreased in HP-positive (0.259 vs 0.276, P =0.01) and CP-seropositive (0.266 vs 0.280, P =0.04) healthy subjects compared with (sero)negatives. Mean apoAI levels were significantly lower in HP-positive healthy subjects (1.46 vs 1.51 g/L, P =0.03) and in CMV-positive healthy subjects (1.47 vs 1.52 g/L, P =0.01) compared with (sero)negative subjects. After multivariable adjustment by means of linear regression analysis, only the association between HP infection and decreased HDL cholesterol (P =0.002), decreased HDL cholesterol to total cholesterol ratio (P =0.005), decreased apoAI (P =0.02), and increased apoB (P =0.02) persisted and remained significant. There was no independent association between other lipoproteins and serological markers of CP or CMV infection. Current infection with HP, but not seropositivity to CP or CMV, was associated with an atherogenic, modified lipid profile. These lipid alterations could explain, at least in part, the reported weak association between chronic HP infection and atherosclerotic diseases.

Rapid Diagnosis of Respiratory Chlamydia pneumoniae Infection by Nested Touchdown Polymerase Chain Reaction Compared with Culture and Antigen Detection by EIA

Chlamydia pneumoniae is a common cause of respiratory tract infection and community-acquired pneumonia. During an extensive outbreak of C. pneumoniae in northern Sweden, 319 respiratory samples from 129 persons were collected. Sputum, throat, and nasopharyngeal samples were obtained and analyzed by nested touchdown polymerase chain reaction (PCR), EIA, and culture in Hep-2 and McCoy cells. Serology was performed by complement fixation and microimmunofluorescence tests. By PCR, 30 patients were diagnosed with C. pneumoniae compared with 26 positive by EIA and 23 by culture. The finding of C. pneumoniae in the respiratory samples was accompanied by serology indicating acute infection in 26 (96%) of 27 patients for whom adequate sera were available. Nested PCR was sensitive and reliable for diagnosing acute respiratory C. pneumoniae infection. Sputum samples had the highest diagnostic efficacy, and the nested type of PCR was superior to one-step PCR. EIA and culture were less sensitive than nested PCR.

Endothelial Dysfunction After Repeated Chlamydia pneumoniae Infection in Apolipoprotein E–Knockout Mice

BackgroundArterial relaxation is largely regulated by endothelial nitric oxide (NO). Its diminished activity has been associated with incipient atherosclerosis. We investigated the endothelium-dependent relaxation of aorta in apolipoprotein E–knockout (apoE-KO) mice exposed to single or repeated Chlamydia pneumoniae inoculation. Methods and ResultsForty-eight apoE-KO mice, 8 weeks old, were inoculated intranasally with C pneumoniae (n=24) or saline (n=24) every 2 weeks over a 6-week period. Twenty mice (10 infected and 10 controls) were killed at 2 weeks and 6 weeks, respectively, after the first inoculation. The smooth muscle tone of aortic rings was measured in vitro at both time points. The norepinephrine-precontracted thoracic aortic rings were successively exposed to methacholine in the absence and presence of NG-nitro-l-arginine methyl ester (L-NAME) and diclofenac. The methacholine-induced relaxation was attenuated in the infected mice at 6 weeks in both the absence and presence of L-NAME (P <0.05 and P <0.01, respectively). When administered together with L-NAME, diclofenac enhanced the relaxation of the L-NAME–pretreated aortas in infected mice at 2 weeks (P <0.05) but not in noninfected mice. The relaxation response from infected mice tended to differ in the same manner at 6 weeks (P <0.1). No intimal thickening was detected at either time point. ConclusionsC pneumoniae impairs arterial endothelial function, and the NO pathway is principally involved. Cyclooxygenase-dependent vasoconstricting products may also account for the infection-induced impaired relaxation. These findings further support the role of C pneumoniae infection in atherosclerosis development.

Contact angles of ultrafiltration membranes and their possible correlation to membrane performance

The captive bubble method was used to describe the wetting characteristics of a number of commercial ultrafiltration (UF) membranes. The membranes belonged to one of two homologous (same material, different cut-off) series made by the same manufacturer. One series was made of polysulphone and the other one of cellulose triacetate. The porosimetric characteristics of the membranes have also been measured. The combined data were used to explain the fouling behaviour of the membranes upon ultrafiltration of solutions containing dextran, whey protein concentrate and silicate sols. The cellulose triacetate series is characterized by lower receding contact angle and smaller contact angle hysteresis and shows better flux behaviour (permeate flux during UF and pure water flux recovery at the end of UF) than the polysulphone series. Within the same series the mean permeability pore size shows a better correlation with membrane flux behaviour than with contact angle hysteresis.

Comparison of Five Serologic Tests for Diagnosis of Acute Infections by Chlamydia pneumoniae

ABSTRACT Serology is often used to diagnose acute infections byChlamydia pneumoniae. In this study paired sera from patients with acute respiratory tract infection during an epidemic ofC. pneumoniae infections were examined by five different antibody tests. These tests were the complement fixation (CF) test, the microimmunofluorescence (MIF) test, a recombinant enzyme immunoassay (rEIA) (Medac) based on a recombinant lipopolysaccharide of chlamydia and measuring antibodies to a common chlamydial antigen, and two tests that utilize preparations of C. pneumoniae organisms, the SeroCp-EIA (Savyon) (with preserved lipopolysaccharide) and the LOY-EIA (Labsystems) (without this antigen). Both of the last two tests should measure specific antibodies to C. pneumoniae, although cross-reacting antibodies may also be detected by the SeroCp-EIA. Acute infection of C. pneumoniae was serologically confirmed in 44% of the cases by at least two different tests. Using an expanded “gold standard,” i.e., the presence of significant reactions in at least two tests, the sensitivity of the CF test was 69%, that of the MIF test was 88%, that of the rEIA was 89%, that of the LOY-EIA was 96%, and that of the SeroCp-EIA was 92%. Specificity was high for all methods, but adjustments of diagnostic criteria were made to several of the tests. The basis for these adjustments and supportive data are presented. Infections of C. pneumoniae were detected in patients from 8 to 83 years of age. Two peaks in the incidence of such infections were observed: one among young teenagers and a second in adults 30 to 45 years of age, corresponding to parents of young teen-agers. The tests were equally sensitive in different age groups. Reinfections seemed to be rare.

Water permeability in ultrafiltration and microfiltration: Viscous and electroviscous effects

Abstract The applicability of Darcys law for explaining the water permeabilities of polymeric UF membranes and ceramic MF membranes was investigated at various temperatures, viscosities, salt concentrations, and trasmembrane pressures. It was found that Darcys law explains the permeabilities well if the viscosity is corrected for electroviscous effects, temperature, and solute concentration. For polymeric UF membranes the compaction of the membranes needs to be taken into account as well. Ceramic MF membranes do not seem compressible for TMPs up to 80 kPa. Increasing the salt concentration from 30 μM to 0.1 M resulted in increases in water fluxes of 2% to 8% both for MF and UF membranes. This apparent permeability increase was explained by electroviscous effects: increased salt concentrations lead to lower zeta-potentials and thinner double-layers, offering less resistance to water passage. From the apparent permeability change the zeta-potentials of the membranes at pH ≈ 7 were calculated. Realistic zeta-potential values were obtained. Water flux measurements at various salt concentrations are thus a simple method to study zeta-potentials of membranes. The resistance (Rm) of the UF membranes was independent of temperature in the range 4–20°C, but increased with increasing transmembrane pressure (TMP). The increase could be described by a power law ΔRm∼TMP0.8, typical for porous solids. The resistance of the ceramic MF membrane was independent of temperature and independent of TMP.

Seropositivity to chlamydial lipopolysaccharide and chlamydia pneumoniae, systemic inflammation and stable coronary artery disease: Negative results of a case-control study

OBJECTIVES We investigated the association between seropositivity to chlamydial lipopolysaccharide (cLPS) or Chlamydia pneumoniae (CP) and angiographically documented coronary artery disease (CAD), and we examined the relationship between serostatus and markers of systemic inflammation. BACKGROUND The potential contribution of CP to atherogenesis is still a matter of debate, and inflammation has been suggested to represent the link between infection and atherosclerotic disease. METHODS Subjects age 40 to 68 years were recruited for this case-control study between October 1996 and November 1997: 312 patients with at least one coronary stenosis >50% and 479 age- and sex-matched blood donors without manifest CAD or history of angina. Antibodies against cLPS and CP, C-reactive protein (CRP), fibrinogen, plasma viscosity, leukocytes and neutrophils were determined. The study had a power of >80% to detect an odds ratio (OR) of 1.55 or above for the prevalence of immunoglobulin (IgG) antibodies against cLPS at a significance level of alpha = 0.05. RESULTS Prevalence of IgG antibodies against cLPS was not different between cases and controls (61% vs. 62%; p = 0.7). The adjusted OR for the presence of CAD given positive IgG serostatus against cLPS was 0.9 (95% CI; 0.6 to 1.3). Similarly, no difference in the prevalence of IgG antibodies against CP was seen (88% vs. 87%; p = 0.6); the adjusted OR was 1.0 (95% CI; 0.6 to 1.6). Markers of inflammation did not show any statistically significant difference between cLPS seropositives and seronegatives. CONCLUSIONS Our results indicate no strong association between CP and CAD, and increased systemic inflammation in patients with CAD does not seem to be due to seropositivity to cLPS or CP.

A clinical and epidemiological study of "ornithosis" caused by Chlamydia psittaci and Chlamydia pneumoniae (strain TWAR).

Ornithosis is a notifiable disease in Sweden since 1954. In 1981 and 1982 a sharp increase in the number of notifications occurred. Since then the number has declined but is still high. A changed epidemiology characterized by no history of bird contact and no common source, raised the suspicion of a new agent. Serological data now suggest that the epidemic was to a substantial part due to Chlamydia pneumoniae (strain TWAR) (48% of the patients during 1981-1982 compared to 9% during 1984-1987). During recent years TWAR infections have thus become uncommon but reappearance can be expected in the near future. The clinical picture as well as the complications appear to be very similar in infections caused by C. pneumoniae and C. psittaci.